All Things NuclearAll Things Nuclear https://allthingsnuclear.org Insights on Science and Security Fri, 18 May 2018 21:52:25 +0000 en-US hourly 1 https://allthingsnuclear.org/wp-content/uploads/2016/01/cropped-favicon-32x32.png All Things Nuclear https://allthingsnuclear.org 32 32 A Response to Roberts and Payne https://allthingsnuclear.org/gkulacki/a-response-to-roberts-and-payne https://allthingsnuclear.org/gkulacki/a-response-to-roberts-and-payne#respond Fri, 18 May 2018 21:52:25 +0000 https://allthingsnuclear.org/?p=15658 A recent letter by Bradley Roberts and Keith Payne responds to a Japanese press account of a blog post that discussed Japanese Vice Foreign Minister Takeo Akiba’s 25 February 2009 presentation to a US congressional commission on US nuclear weapons policy. Read More

]]>
A recent letter by Bradley Roberts and Keith Payne responds to a Japanese press account of a blog post that discussed Japanese Vice Foreign Minister Takeo Akiba’s 25 February 2009 presentation to a US congressional commission on US nuclear weapons policy. Reports of Mr. Akiba’s presentation created some controversy in the Japanese Diet, since he may have made statements that contradict the spirit, if not the letter, of a long-standing Diet resolution. That resolution, adopted decades ago and reaffirmed many times since, prohibits any transportation of US nuclear weapons into Japanese territory.

The 1969 US-Japan agreement granting the United States “standby retention and activation” of nuclear weapons storage sites on US military bases in Okinawa.

Roberts and Payne mistakenly claim the document on which the post was based does not exist, despite the fact that it was published on the website of a non-governmental Japanese arms control expert more than a month before their letter appeared in the Japan Times.

The document exists.

Roberts and Payne also claimed that because the Japanese participants were “off-the-record” no records were kept. This too is incorrect. There may be no transcript of Mr. Akiba’s presentation, but an April 10 reply by the cabinet to questions from Rep. Seiji Osaka confirmed that the Foreign Ministry kept records on the proceedings of the US commission where representatives of the ministry were present. The same reply was repeated in a document issued on April 13 by the Security Treaty Division of the North American Bureau of the Ministry of Foreign Affairs. The United States Institute of Peace (USIP) also archived documents that describe the discussions between the commissioners and the Japanese officials.

Records were kept.

Meetings are often held “off the record” to allow public officials to express their personal opinions. Rep. Osaka asked the Abe government whether the Foreign Ministry officials who participated in the proceedings of the US commission were acting in a personal or an official capacity. The April 10 reply by the cabinet confirmed that all of the Japanese officials who participated in the proceedings were acting in an official capacity under the direction of Foreign Minister Nakasone.

The three-page document Akiba presented to the US commission is therefore an official record of the Japanese government’s views on the role of US nuclear weapons in the defense of Japan. So are any oral statements Akiba and the other Japanese officials gave to the commission.

Some of those oral statements were recorded in hand-written notes on the margins of the document. Those notes contain an abbreviated rendition of a conversation between Akiba and James Schlesinger in which the Japanese minister gives a favorable response to Schlesinger’s question about building nuclear weapons storage facilities in Okinawa. Roberts and Payne recall the conversation. They note that Akiba “clearly set out the three non-nuclear principles,” which the Japanese official does in the hand-written notes on his conversation with Schlesinger. Yet Roberts and Payne neglected to mention Mr. Akiba also said that “some quarters talk about revising the third principle,” which would be necessary if the United States were to bring nuclear weapons into Japan or prepare to store them in Okinawa.

The language in the hand-written notes makes it difficult to assess whether Mr. Akiba is among those who want to revise the third principle. But his favorable response to Schlesinger’s proposal to construct nuclear weapons storage sites in Okinawa deserves more careful scrutiny.

Notes are often incomplete and sometimes inaccurate. Memories, especially of a conversation that took place nine years ago, can be faulty. One way to help clarify this matter is for the United States Institute of Peace (USIP) to release the Foreign Ministry from its promise of confidentiality and encourage the ministry to respond to Diet requests for access to its records. USIP should also grant the Diet access to all materials on the proceedings of the commission it may hold in its archives. Greater transparency, from both sides, is the best way to set the record straight.

]]>
https://allthingsnuclear.org/gkulacki/a-response-to-roberts-and-payne/feed 0
High Energy Arc Faults and the Nuclear Plant Fire Protection IOU https://allthingsnuclear.org/dlochbaum/high-energy-arc-faults https://allthingsnuclear.org/dlochbaum/high-energy-arc-faults#respond Thu, 17 May 2018 18:01:06 +0000 https://allthingsnuclear.org/?p=15685 Last year, we posted a commentary and an update about a high energy arc fault (HEAF) event that occurred at the Turkey Point nuclear plant in Florida. The update included color photographs obtained from the Nuclear Regulatory Commission (NRC) via a Freedom of Information Act request showing the damage wrought by the explosion and ensuing fire. Read More

]]>
Last year, we posted a commentary and an update about a high energy arc fault (HEAF) event that occurred at the Turkey Point nuclear plant in Florida. The update included color photographs obtained from the Nuclear Regulatory Commission (NRC) via a Freedom of Information Act request showing the damage wrought by the explosion and ensuing fire. Neither the HEAF event or its extensive damage surprised the NRC—they had been researching this fire hazard for several years. While the NRC has long known about this fire hazard, its resolution remains unknown. Meanwhile, Americans are protected from this hazard by an IOU. The sooner this IOU is closed out, the better that Americans in jeopardy will be really and truly protected.

What is a HEAF?

The Nuclear Energy Agency (NEA), which has coordinated international HEAF research efforts for several years, defines HEAF this way: “An arc is a very intense abnormal discharge of electrons between two electrodes that are carrying an electrical current. Since arcing is not usually a desirable occurrence, it is described as an arcing fault.”

Nuclear power plants generate electricity and use electricity to power in-plant equipment. The electricity flows through cables or metal bars, called buses. An arc occurs when electricity jumps off the intended pathway to a nearby metal cabinet or tray.

Electricity is provided at different voltages or energy levels for different needs. Home and office receptacles provide 120-volt current. Nuclear power plants commonly have higher voltage electrical circuits carrying 480-volt, 4,160-volt, and 6,900-volt current for motors of different sizes. And while main generators at nuclear plants typically produced electricity at 22,000 volts, onsite transformers step up the voltage to 345,000 volts or higher for more efficient flow along the transmission lines of the offsite power grid.

How is the Risk from HEAF Events Managed?

Consistent with the overall defense-in-depth approach to nuclear safety, HEAF events are managed by measures intended to prevent their occurrence backed by additional measures intended to minimize consequences should they occur.

Preventative measures include restrictions on handling of electrical cables during installation. Limits on how much cables can be bent and twisted, and on forces applied when cables are pulled through wall penetrations seek to keep cable insulation intact as a barrier against arcs. Other preventative measures seek to limit the duration of the arc through detection of the fault and automatic opening of a breaker to stop the flow of electrical current through the cables (essentially turning the arc off).

Mitigative measures include establishing zones of influence (ZOI) around energized equipment that controls the amount of damage resulting from a HEAF event. Figure 1 illustrates this concept using an electrical cabinet as the example Electrical cabinets are metal boxes containing breakers, relays, and other electrical control devices. Current fire protection regulatory requirements impose a 3-foot ZOI around electrical cabinets and an 18-inch ZOI above them. Anything within the cabinet and associated ZOI is assumed to be damaged by the energy released during a HEAF event. Sufficient equipment must be located outside the affected cabinet and its ZOI to survive the event and adequately cool the reactor core to prevent meltdown.

Even with these preventative and mitigative measures, NEA recognized the hazard that HEAF events poses when it wrote in a May 2017 report: “The electrical disturbance initiating the HEAF often causes loss of essential electrical power and the physical damage and products of combustion provide significant challenges to the operators and fire brigade members handling the emergency. It is clear that HEAFs present one of the most risk significant and challenging fire scenarios that a [nuclear power plant] will face.”

What is the Problem with HEAF Risk Management?

Actual HEAF events have shown that the preventative and mitigative measures intended to manage the hazard have shortcomings and weaknesses. For example, arcs have sometimes remained energized far longer than assumed, enabling the errant electricity to wreak more havoc.

Additionally, HEAF events have damaged components far outside the assumed zones of influence, such as in the Turkey Point event from March 2017. In other words, the HEAF hazard is larger than its defenses.

How is the HEAF Risk Management Problem Being Resolved?

On March 11, 2011, an earthquake offshore of Japan and the tsunami it spawned led to the meltdown of three reactors at the Fukushima Daiichi nuclear plant. That earthquake also caused a HEAF event at the Onagawa nuclear plant in Japan. The ground motion from the earthquake prevented an electrical circuit breaker from opening to limit the duration of the arc. The HEAF event damaged equipment and started a fire (Fig. 2). Because the fire brigade could not enter the room due to heat and smoke, the fire blazed for seven hours until it had consumed all available fuel. As an NRC fire protection engineer commented in April 2018, “If Fukushima wasn’t occurring, this is probably what would have been in the news headlines.” Onogawa was bad. Fukushima was just worse.

Research initiated in Japan following the Onagawa HEAF event sought to define the factors affecting the severity of the events. Because the problem was not confined to nuclear power plants in Japan, other countries collaborated with the Japanese researchers in pursuit of a better understanding of, and better protection for, HEAF events.

The NRC participated in a series of 26 tests conducted between 2014 and 2016 using different types of electrical panels, bus bar materials, arc durations, electrical current voltages, and other factors. The results from the tests enabled the NRC to take two steps.

First, the NRC entered HEAF events into the agency’s generic issues program in August 2017. In a related second step, the NRC formally made the owners of all operating US nuclear power plants aware of this testing program and its results via an information notice also issued in August 2017. The NRC has additionally shared its HEAF information with plant owners during the past three Regulatory Information Conferences and several other public meetings and workshops.

The NRC plans a second series of tests to more fully define the conditions that contribute to the severity of HEAF events.

How Are HEAF Events Tested?

Test 23 during the Phase I program subjected a 480-volt electrical cabinet with aluminum bus material to an arc lasting 7.196 seconds. Figure 3 shows the electrical cabinet with its panel doors opened prior to the test. A pointer on the left side of the picture shows the location where the arc was intentionally caused.

Fig. 3 (Source: Nuclear Energy Agency)

To induce an arc for the test, a wire was wrapped around all three phases of the 480-volt alternating current connectors within one of the cabinet’s panels as shown in Figure 4. On the right edge of the picture is a handswitch used to connect or disconnect electrical power flowing into the cabinet via these buses to in-plant electrical loads.

Fig. 4 (Source: Nuclear Energy Agency)

Instrumentation racks and cameras were positioned around the cabinet being tested. The racks included instruments measuring the temperature and pressure radiating from the cabinet during the HEAF event. High-speed, high definition cameras recorded the progression of the event while infrared cameras captured its thermal signature. A ventilation hood positioned over the cabinet connected to a duct with an exhaust fan conducted smoke away from the area to help the cameras see what was happening. More importantly, the ventilation duct contained instruments measuring the heat energy and byproducts released during the event.

What Are the HEAF Test Results?

For a DVD containing reports on the HEAF testing conducted between 2014 and 2016 as well as videos from the 26 tests conducted during that period, send an email with your name and address to RES_DRA_FRBQnrc.gov. Much of the information in this commentary comes from materials on the DVD the NRC mailed me in response to my request.

Test 4 in the Phase I Program subjected a 480-volt electrical cabinet with aluminum bus material to an arc lasting only 0.009 seconds (i.e., 9 milliseconds). The short duration arc had minimal consequences, entirely missed if one blinks at the wrong time while watching the video. This HEAF event did not damage components within the electrical cabinet, yet alone any components outside the 3-foot zone of influence around it.

Test 3 in the Phase I Program subjected a 480-volt electrical cabinet with copper bus material to an arc lasting 8.138 seconds. The longer duration arc produced greater consequences than in Test 4. But the video shows that the consequences are largely confined to the cabinet and zone of influence.

Test 23 in the Phase I Program subjected a 480-volt electrical cabinet with aluminum bus material to an arc lasting 7.196 seconds. The voltage level and arc duration for Test 23 were essentially identical to that for Test 3, but the consequences were significantly different. Aluminum behaved differently than copper during the HEAF event, essentially fueling the explosion and ensuing fire. As a result, the damage within the cabinet, zone of influence, and even beyond the 3-foot zone of influence was much greater. For example, some of the instruments on the rack positioned just outside the 3-foot zone of influence were vaporized.

Until debris from the event obscured the lens of a camera positioned many feet outside the 3-foot zone of influence, a side view of the Test 23 HEAF event showed it was a bigger and badder event than the HEAF event in Test 3 and the HEAF event in Test 4.

Figure 6 shows the electrical cabinet with its panel doors open after Test 23. The cabinet clearly looks different from its pre-test appearance (see Figure 4). But this view does not tell the entire story.

Fig. 6 (Source: Nuclear Energy Agency)

Figure 7 shows the left side of the electrical cabinet after Test 23. The rear upper left corner of the cabinet is missing. It was burned and/or blown away by the HEAF event. The cabinet is made of metal, not wood, plastic, or ice. The missing cabinet corner is compelling testimony to the energy released during HEAF events.

Fig. 7 (Source: Nuclear Energy Agency

Tests 3, 4 and 23 all featured electrical cabinets supplied with 480-volt power.

Tests 4 and 23 each featured aluminum bus material. Test 4 had negligible consequences while Test 23 had significant consequences, attesting to the role played by arc duration. The arc lasted 0.009 seconds in Test 4 while it lasted 7.196 seconds in Test 23.

Tests 3 and 23 featured arcs lasting approximately 8 seconds. Test 23 caused substantially greater damage within the electrical cabinet and beyond the 3-foot zone of influence due to the presence of aluminum rather than copper materials.

How Vulnerable Are US Nuclear Plants to HEAF Events?

The Phase I series of tests revealed that HEAF events depend on the voltage level, the conducting material (i.e., copper, iron, or aluminum), and the arc duration. The higher the voltage, the greater the amount of aluminum, and the longer the arc duration, the greater the consequences from HEAF events.

The NRC received results in 2017 from an industry survey of US nuclear plants. The survey showed that the plants have electrical circuits with voltage levels of 480, 4160, 6900, and 22000 volts. The survey also showed that while some plants did not have electrical circuits with components plated with aluminum, many did.

As to arc durations, actual HEAF events at US plants have involved arc durations longer than the 8 seconds used in Tests 3 and 23. The May 2000 event at Diablo Canyon lasted 11 seconds. The March 2010 event at HB Robinson last 8 to 12 seconds. And the June 2011 event at Fort Calhoun last 42 seconds and likely would have lasted even longer had operators not intervened by manually opening an electrical breaker to end the event.

So, many US nuclear plants have all the ingredients necessary for really nasty HEAF events.

What Might the Fixes Entail?

The testing program results to date suggest a tiered approach to the HEAF event solution. Once the key factors (i.e., combinations of voltage levels, materials, and arc durations) are definitively established, they can be used to screen out configurations within the plant where a HEAF event cannot compromise safety margins. For example, a high voltage electrical cabinet with aluminum bus material and suspect arc duration limiters might need no remedies if it is located sufficiently far away from safety components that its HEAF vaporization carries only economic rather than safety implications. Similarly, configurations with voltage levels and materials that remain bound by the current assumptions like the 3-foot zone of influence would require no remedies.

When a configuration cannot be screened out, the remedy might vary. In some cases, it might involve providing more reliable, quick-acting fault detection and isolation systems that limit the duration of the arc. In other cases, replacing aluminum buses with copper or iron buses might be a suitable remedy. And the fix might be simply installing a protective wall between an electrical cabinet and safety equipment.

Further HEAF testing will expand knowledge of the problem, thus more fully informing the decisions about effective solutions.

UCS Perspective

It has been known for many years now that HEAF events could cause wider damage than currently assumed in designing and applying fire protection measures. As a result, a fire could damage primary safety systems and their backups—the very outcome the fire protection regulatory requirements are intended to prevent.

This is normally the time and spot where I chastise the NRC for dragging its feet in resolving this known safety hazard. But while years have passed since the HEAF hazard flag was first raised, the NRC’s feet have been busy. For while it was known that HEAF events could cause greater damage than previously realized, it was not known what factors played what roles in determining the severity of HEAF events and the damage they inflict. The NRC joined regulatory counterparts worldwide in efforts designed to fill in these information gaps. That knowledge was vitally needed to ensure that a real fix, rather than an ineffective band-aid fix, was applied.

That research took time to plan and conduct. And further research is needed to fully define the problem to find its proper solution. In the meantime, the NRC has been very forthcoming with plant owners and the public about its concerns and associated learnings to date.

While the NRC’s efforts to better understand HEAF events may be justified, it’s worth remembering that the agency’s intentions and plans are little more than IOUs to the millions of Americans living close to vulnerable nuclear plants. IOUs provide zero protection. The NRC needs to wrap up its studies ASAP and turn the IOUs into genuine protection.

]]>
https://allthingsnuclear.org/dlochbaum/high-energy-arc-faults/feed 0
Made in Chattanooga https://allthingsnuclear.org/dlochbaum/made-in-chattanooga https://allthingsnuclear.org/dlochbaum/made-in-chattanooga#comments Thu, 10 May 2018 19:42:23 +0000 https://allthingsnuclear.org/?p=15676 What do the Arkansas Nuclear One Unit 2, Beaver Valley Unit 1, Beaver Valley Unit 2, Big Rock Point, Callaway, Calvert Cliffs Unit 1, Calvert Cliffs Unit 2, Catawba Unit 2, Comanche Peak Unit 1, Comanche Peak Unit 2, Connecticut Yankee, Cooper, Diablo Canyon Unit 1, Diablo Canyon Unit 2, Donald C. Read More

]]>
What do the Arkansas Nuclear One Unit 2, Beaver Valley Unit 1, Beaver Valley Unit 2, Big Rock Point, Callaway, Calvert Cliffs Unit 1, Calvert Cliffs Unit 2, Catawba Unit 2, Comanche Peak Unit 1, Comanche Peak Unit 2, Connecticut Yankee, Cooper, Diablo Canyon Unit 1, Diablo Canyon Unit 2, Donald C. Cook Unit 1, Edwin I. Hatch Unit 1, Edwin I. Hatch Unit 2, Fort Calhoun, HB Robinson, Indian Point Unit 1, Indian Point Unit 2, Indian Point Unit 3, James A. FitzPatrick, Joseph M. Farley Unit 1, Joseph M. Farley Unit 2, Fermi Unit 2, Kewaunee, LaSalle Unit 1, Maine Yankee, Marble Hill, McGuire Unit 1, Millstone Unit 1, Millstone Unit 2, Millstone Unit 3, Nine Mile Point Unit 1, Oyster Creek, Palisades, Palo Verde Unit 1, Palo Verde Unit 2, Palo Verde Unit 3, Pilgrim, Point Beach Unit 2, Salem Unit 1, Salem Unit 2, San Onofre Unit 1, San Onofre Unit 2, San Onofre Unit 3, Seabrook, South Texas Project Unit 1, South Texas Project Unit 2, St. Lucie Unit 1, St. Lucie Unit 2, Vogtle Unit 1, Vogtle Unit 2, Waterford, and Wolf Creek nuclear power reactors have in common?

True, they are all mentioned in this same question. But the subject commonality has a broader dimension.

Also true, they are all located on planet earth. But the subject commonality has a narrower dimension.

Hint: Check out the title of this commentary.

Yes, the reactor vessels for all these nuclear plants, and many others worldwide, were manufactured by Combustion Engineering at their factory in Chattanooga, Tennessee.

Indeed, the Chattanooga factory made the vessels for boiling water reactors like FitzPatrick and Pilgrim, for Westinghouse pressurized water reactors like Diablo Canyon and Indian Point and for Combustion Engineering pressurized water reactors like Palo Verde and Waterford.

In the days before FedEx, how did reactor vessels made in the hills of east Tennessee get to so many locations coast to coast? The Tennessee River winds through Chattanooga and empties into the Mississippi River. Whenever possible, the reactor vessels were lifted onto barges in Chattanooga and floated to the plant sites. For example, the Unit 1 reactor vessel for the Nine Mile Point nuclear plant in Oswego, New York took the scenic route down the Tennessee River, up the Mississippi River, up the Illinois River, across four of the five Great Lakes.

Fig. 1 (Source: Daily Standard (October 7, 1966))

It took 29 days for Pilgrim’s reactor vessel to make the 3,587-mile journey down the Tennessee and Mississippi Rivers, across the Gulf of Mexico and along the Atlantic coast to Plymouth, Massachusetts. (The plant is scheduled to permanently shut down by June 2019. On behalf of my fellow citizens of Chattanooga, the current owner should check out the “No Return” provision in the contract.)

Fig. 2 (Source: UPI Telephoto published in News Journal (March 4, 1970))

The Unit 1 reactor vessel for the San Onofre Nuclear Generating Station in southern California began its 2,000-mile journey on a barge, was transferred onto a freighter for passage through the Panama Canal, was transferred back onto a barge, and then loaded onto a train car for delivery to the site.

Fig. 3 (Source: Daily Republican (April 23, 1965))

Not all the journeys were event-free. The Unit 3 reactor vessel for the Indian Point nuclear plant in Buchanan, New York was dropped on January 12, 1971, as it was being unloaded at the plant. Well, it was not actually dropped. It underwent an “unscheduled descent during its installation” at the plant. An overhead crane rated for 175-tons was being used to lift the 456-ton package of reactor vessel and shipping rig. Somehow, the motor for the 175-ton rated crane became overheated as it was lifting the 456-ton load. The 456-ton load had been raised from its original horizontal configuration to nearly the vertical (i.e., 90°) position when the lift was halted to let the overheated crane motor cool down. The 175-ton crane’s hoist failed, dropping the load—or letting the load make its unscheduled descent back to the horizontal position.

Scientists from Oak Ridge, representatives of Combustion Engineering in Chattanooga, and workers from Westinghouse huddled to determine whether the unscheduled descent of the reactor vessel resulted in its unscheduled dis-use. They reviewed results from magnetic particle and ultrasonic examinations and concluded the vessel could be used.

Scientists from the Oak Ridge National Laboratory traveled to Buchanan to view the Unit 3 reactor vessel. They heard contradictory accounts as to the position of the reactor vessel when it began its unscheduled descent. Some eyewitnesses said the vessel and rig were about three feet off the ground. Others insisted it was not off the ground at all. Similarly, the scientists received varying accounts of how long it took the vessel to complete its unscheduled decent. Some eyewitnesses reported the descent took 15 seconds. Others claimed the descent went on for nearly 60 seconds. The discrepancies might be attributed to the eyewitnesses making unscheduled departures from the vicinity.

UCS Perspective

UCS has staffed a remote office in Chattanooga for the past eight years. At the time, we knew the city was the location for the International Towing Museum, but did not realize that the city played such a prominent role in the development of nuclear power reactors in the United States. And as if making tow trucks and reactor vessels was not enough, but Moon Pies were invented in Chattanooga in 1917.

Chattanooga also has the offices for the Nuclear Division of the Tennessee Valley Authority (TVA), with TVA’s Sequoyah Nuclear Plant within sight of downtown. Chattanooga also has the Nuclear Regulatory Commission’s Technical Training Center as well as a Westinghouse training facility.

But Chattanooga no longer makes reactor vessels. Combustion Engineering scaled back manufacturing at the factory as demand for nuclear components dwindled in the U.S. and abroad. In 2007, the nearly idled manufacturing plant was acquired by French-based Alstom with intentions to make components to support the nuclear renaissance. The factory did not need a first shift, yet alone a second or third shift, to handle all the non-orders for reactor vessels and other nuclear plant parts. The factory closed shop in 2016.

But don’t despair. Chattanooga still makes Moon Pies and tow trucks.

]]>
https://allthingsnuclear.org/dlochbaum/made-in-chattanooga/feed 2
NRC Cherry-Picking in the Post-Fukushima Era: A Case Study https://allthingsnuclear.org/guest-commentary/nrc-post-fukushima https://allthingsnuclear.org/guest-commentary/nrc-post-fukushima#comments Mon, 07 May 2018 13:31:14 +0000 https://allthingsnuclear.org/?p=15662 In the late 1960s, the Atomic Energy Commission (AEC), the forerunner of the NRC, paid the very companies that designed nuclear reactors—Westinghouse and General Electric (GE)—to test the efficacy of their own emergency cooling systems.

In the event of an accident in which a reactor loses water, uncovering the fuel rods—called a “loss-of-coolant accident”—these systems inject water back into the reactor in an attempt to prevent a meltdown. Read More

]]>
In the late 1960s, the Atomic Energy Commission (AEC), the forerunner of the NRC, paid the very companies that designed nuclear reactors—Westinghouse and General Electric (GE)—to test the efficacy of their own emergency cooling systems.

In the event of an accident in which a reactor loses water, uncovering the fuel rods—called a “loss-of-coolant accident”—these systems inject water back into the reactor in an attempt to prevent a meltdown. The tests that Westinghouse and GE performed were named the Full Length Emergency Cooling Heat Transfer (FLECHT) tests. The FLECHT tests simulated fuel rods undergoing a loss-of-coolant accident. The tests were intended to be as realistic as possible: bundles of 12-foot-tall rods, simulating fuel rods, were electrically heated up to reactor-accident temperatures and then inundated with cooling water.

Several of the tests were geared toward assessing how well the outer casing of fuel rods, called “cladding,” would endure in accident conditions. The cladding of fuel rods is primarily zirconium, a silver-colored metal. After the injection of water in an accident, hot-zirconium cladding is intended to endure the thermal shock of swift re-submergence and cooling. The cladding must not be stressed to its failure point. It is crucial that the fuel cladding perform well in an accident because it is a barrier preventing the release of highly radioactive materials into the exterior environment.

Figure 1. Source: Westinghouse)

Robert Leyse, my father, a nuclear engineer employed by Westinghouse, conducted a number of the FLECHT tests. On December 11, 1970, one of those tests, designated as Run 9573, had unexpected results. In Run 9573, a section of the test bundle’s zirconium cladding essentially caught on fire. The cladding burned in steam—then, when cooled, shattered like overheated glass doused with cold water.

Mr. Leyse instructed a lab assistant to take photographs of the destroyed test bundle, one of which is displayed as Figure 1. In a report on the FLECHT tests that Mr. Leyse coauthored, Westinghouse referred to the severely burnt, shattered section as the “severe damage zone” and noted that “the remainder of the [test] bundle was in excellent condition.”

Westinghouse’s FLECHT data is nearly 50 years old yet it is still highly regarded. The AEC used some of the FLECHT data to establish regulations that remain in place to this day. Westinghouse’s report on the FLECHT tests states that data from the first 18 seconds of Run 9573—before the cladding caught fire—is valid.

Concern over the extent zirconium burns in reactor accidents

In 2009, I submitted a rulemaking petition (PRM-50-93), requesting new regulations intended to improve public and plant worker safety. PRM-50-93 contends industry and NRC computer safety models under-predict the extent zirconium fuel cladding burns in steam. In more technical terms, the petition alleges models under-predict the rates at which zirconium chemically reacts with steam in a reactor accident. I buttressed my claims by citing data from FLECHT Run 9573 and other experiments conducted with bundles of zirconium cladding.

The zirconium-steam reaction produces zirconium dioxide, hydrogen, and heat. In a serious accident, the rate of the zirconium-steam reaction increases as local cladding temperatures increase within the reactor core. As the reaction speeds up, more and more heat is generated; in turn, the additional heat increases the rate of the reaction, potentially leading to thermal runaway and a meltdown.

It is problematic that the zirconium-steam reaction generates hundreds of kilograms of explosive hydrogen gas in a meltdown. In the Fukushima Daiichi accident—in which three reactors melted down—hydrogen leaked out of reactors’ containments and detonated, blowing apart reactor buildings. The release of radioactive material prompted the evacuation of tens of thousands of people and rendered a large area of land uninhabitable.

A “high priority”

In 2010, the NRC said its technical analysis of my 2009 rulemaking petition (PRM-50-93) was a “high priority.” Then, in 2011, the agency issued a press release announcing it intended to “increase transparency” in its petition review process by releasing preliminary evaluations of PRM-50-93. The announcement said the final decision on the petition would “not be issued until after the NRC Commissioners…considered all staff recommendations and evaluations.”

As part of the preliminary technical analysis of PRM-50-93, the NRC staff conducted computer simulations of FLECHT Run 9573. They compared the results of their simulations to data Westinghouse reported. However, there is a major problem with the staff’s simulations. They did not simulate the section of the test bundle that ignited. (Or if they did simulate that section, they decided not to release their findings.)

By way of an analogy: what the NRC staff did would be like simulating a forest fire and omitting trees reduced to ash and only simulating those that had been singed. After doing such a bogus simulation one might try to argue that trees actually do not burn down in forest fires. The staff basically did just that. They used the results of their simulations to argue that models of the zirconium-steam reaction are not flawed—that reaction rates are not under-predicted.

On January 31, 2013, I gave a presentation to the five commissioners who were heading the NRC at the time. They invited me to present my views in a meeting addressing public participation in the NRC’s rulemaking process. They apparently wanted my insights, because, in 2007, I raised a safety issue in a rulemaking petition (PRM-50-84) that they decided to incorporate into one of their regulations. I had pointed out that computer safety models neglected to simulate a phenomenon affecting the performance of fuel rods in a loss-of-coolant accident.

In my presentation, I criticized the staff’s computer simulations of FLECHT Run 9573. I said: “You cannot do legitimate computer simulations of an experiment that [caught on fire] by not actually modeling the section of the test bundle that [caught on fire].” In the Q and A session, Commissioner William Magwood assured me that he and the other commissioners would instruct the staff “to follow up on” my comments, including my criticism of the staff’s simulations of Run 9573. Then, five weeks after the meeting, Annette Vietti-Cook, Secretary of the Commission, instructed the staff to “consider and respond” to my comments on its review of PRM-50-93.

I hoped the staff would promptly conduct and report on legitimate computer simulations of FLECHT Run 9573. Instead, in March 2013, the staff restated that their prior, incomplete simulations of Run 9573 over-predicted the extent that zirconium burns in steam, indicating computer safety models are beyond adequate.

In November 2015, after I made a series of additional complaints, with help from Dave Lochbaum of the Union of Concerned Scientists, Aby Mohseni, Deputy Director of the NRC’s Division of Policy and Rulemaking, disclosed results of computer simulations of FLECHT Run 9573 including the section of the test bundle that ignited. The simulations drastically under-predict temperatures Westinghouse reported for that section.

The NRC’s severe-damage-zone computer simulations of Run 9573

The NRC’s severe-damage-zone computer simulations predicted cladding and steam temperatures for the FLECHT Run 9573 test bundle, at the 7-foot elevation, at 18 seconds into the experiment. (The severe damage zone was approximately 16 inches long, centered at the 7-foot elevation of the 12-foot-tall test bundle.)

The highest cladding temperature the severe-damage-zone simulations of Run 9573 predicted is 2,350°F, at the 7-foot elevation, at 18 seconds. Westinghouse reported that at 18.2 seconds into Run 9573, cladding temperatures by the 7-foot elevation exceeded 2,500°F. Cladding temperatures by the 7-foot elevation were not directly measured by thermocouples (temperature-measuring devices); however, Westinghouse reported that electrical heaters installed in the cladding began to fail at 18.2 seconds, by the 7-foot elevation, after local cladding temperatures reached higher than 2,500°F. Hence, even considering the time difference of a 0.2 second, one can infer that the severe-damage-zone simulations of Run 9573 under-predicted the cladding temperature by a margin of more than 100°F (at the section of the test bundle that ignited).

(Note that there is a time difference of a 0.2 second between the time the NRC picked for its simulations of Run 9573 and the time that the electrical heaters began to fail in the experiment. In the staff’s incomplete simulations of Run 9573—reported in the staff’s preliminary evaluations of PRM-50-93—the highest predicted cladding temperature is 2,417.5°F, at the 6-foot elevation, at 18 seconds. And the highest predicted cladding temperature increase rate is 29°F per second, at the 6-foot elevation, at 18 seconds. From these predictions we can infer that—although the value has not been reported—the highest predicted cladding temperature increase rate would be approximately 29°F per second or less, at the 7-foot elevation, at 18 seconds.)

In Run 9573, at the 7-foot elevation, the heat generated by the zirconium-steam reaction radiated to the local environment, heating the steam in proximity. The highest steam temperature the NRC’s severe-damage-zone simulations of Run 9573 predicted is 2,055°F, at the 7-foot elevation, at 18 seconds. Westinghouse reported that at 16 seconds into Run 9573, a steam-probe thermocouple mounted at the 7-foot elevation directly recorded steam temperatures that exceeded 2,500°F. And a Westinghouse memorandum (included as Appendix I of PRM-50-93) stated that after 12 seconds, the steam-probe thermocouple recorded “an extremely rapid rate of temperature rise (over 300°F/sec).” (Who knows how high the local steam temperatures actually were at 18 seconds; they were likely hundreds of degrees Fahrenheit higher than 2,500°F.) Hence, the severe-damage-zone simulations of Run 9573 under-predicted the steam temperature by a margin of more than 400°F (by the section of the test bundle that ignited).

The fact the NRC’s severe-damage-zone simulations under-predict cladding and steam temperatures that occurred in Run 9573 is powerful evidence indicating models under-predict the zirconium-steam reaction rates that occur in reactor accidents.

Qualifying power level increases for reactors

Since the 1970s, the NRC has approved more than 150 power level increases (termed “power uprates”) for reactors in the US fleet, enabling them to generate more and more electricity. An important part of qualifying a power uprate is to provide assurance with computer simulations that emergency systems would be able to prevent a meltdown if there were a loss-of-coolant accident at the proposed, higher power level.

A computer simulation is supposed to over-predict the severity of a potential nuclear accident. A margin of safety is established when a reactor’s power level is qualified by a “conservative” simulation—one that overcompensates. Meltdowns are less likely to occur if the reactor operates at a safe power level, providing a sufficient safety margin.

The extent zirconium burns at high temperatures has a major impact on the progression and outcome of a reactor accident. If zirconium-steam reaction rates are under-predicted by computer safety models, they will also under-predict the severity of potential reactor accidents. And, if power uprates have been qualified by models under-predicting the severity of potential accidents, it is likely power levels of reactors have been set too high and emergency cooling systems might not be able to prevent a meltdown in the event of a loss-of-coolant accident.

A petition review process of beyond eight years (with cherry-picking)

The NRC staff’s technical analysis of my 2009 rulemaking petition (PRM-50-93) was completed on March 18, 2016, but was not made publicly available until March 5, 2018, nearly two years later. The technical analysis signals an intention to deny PRM-50-93. It concludes with the statement: “Each of the petition’s key presumptions was investigated in detail. … The petition fails to provide any new information that supports a rule change. The NRC staff does not agree with the petition’s assertions, and concludes that revisions to [NRC regulations] or other related guidance are not necessary.”

Interestingly, a NRC staff e-mail, released in response to a Freedom of Information Act request, reveals that in August 2015—seven months before their technical analysis was completed—the staff already planned to deny PRM-50-93. At that time, the staff intended to announce their denial in August 2016.

The 2016 technical analysis of PRM-50-93 fails to discuss or even mention the results of the computer simulation of FLECHT Run 9573 that Mr. Mohseni disclosed in November 2015. Certain staff members appear intent on denying PRM-50-93 to the extent that they’re willing to make false statements and omit evidence lending support to the petition’s allegations. They appear determined to bury the fact their own computer simulation underpredicts, by a large margin, temperatures Westinghouse reported for the section of the Run 9573 test bundle that ignited.

The staff members who conducted the 2016 technical analysis of PRM-50-93 did not comply with the commissioners who directed them, in January 2013, to “consider and respond” to my criticisms of their simulation of Run 9573. The 2016 technical analysis has a section titled “Issues Raised at the Public Commission Meeting in January 2013;” however, that section fails to discuss the simulation results Mr. Mohseni disclosed in November 2015.

In April 2014, I submitted over 50 pages of comments alleging the staff’s preliminary evaluations of PRM-50-93 have numerous errors as well as misrepresentations of material I discussed to support my arguments. In my opinion, the 2016 technical analysis has the same shortcomings. I suspect that portions of the technical analysis have been conducted in bad faith. Perhaps certain staff members fear enacting the regulations I requested would force utilities to lower the power levels of reactors.

As a member of the public, who spent months writing PRM-50-93, I personally resent the way certain staff members disrespect science and efforts of the public to participate in the NRC’s rulemaking process. (The NRC gives lip service to encouraging public participation. Its website boasts that the agency is “committed to providing opportunities for the public to participate meaningfully in the NRC’s decision-making process.”) Even worse, much worse, their cynical actions undermine public safety.

In a written decision, D.C. Circuit appeals court judges said it was “nothing less than egregious” when a federal agency took longer than six years to review a rulemaking petition. The NRC has been reviewing PRM-50-93 for longer than eight years—procrastinating as well as cherry-picking.

UCS perspective

[What follows was written by Dave Lochbaum, Director of the Nuclear Safety Project at the Union of Concerned Scientists]

I (Dave Lochbaum) invited Mark Leyse to prepare this commentary. I more than monitored Mark’s efforts—I had several phone conversations with him about his research and its implications. I also reviewed and commented on several of his draft petitions and submissions.

Mark unselfishly devoted untold hours researching this safety issue and painstakingly crafting his petition. He did not express vague safety concerns in his petition. On the contrary, his concerns were described in excruciating detail with dozens of citations to source documents. (Reflective of that focused effort, Mark’s draft of this commentary contained 33 footnotes citing sources and page numbers, supporting his 2,300-plus words of text. I converted the footnotes to embedded links, losing chapter and verse in the process. Anyone wanting the specific page numbers can email me for them.)

Toward the end of his commentary, Mark expresses his personal resentment over the way the NRC handled his concerns. It is not my petition, but I also resent how the NRC handled, or mis-handled, Mark’s sincere safety concerns. He made very specific points that are solidly documented. The NRC refuted his concerns with vague, ill-supported claims. If Mark’s safety concerns are unfounded, the NRC must find a way to conclusively prove it. “Nuh-uh” is an unacceptable way to dismiss a nuclear safety concern.

In addition to handling Mark’s safety concerns shoddily from a technical standpoint, the NRC mistreated his concerns process-wise. Among other things, Mark asked the NRC staff to explain why it had not conducted a complete computer simulation of Westinghouse’s experiment, FLECHT Run 9573. The NRC refused to answer his questions, contending that its process did not allow it to release interim information to him. I protested to the NRC on Mark’s behalf, pointing out case after case where the NRC had routinely provided interim information about rulemaking petitions to plant owners. I asked why the NRC’s process treated members of the public one way and plant owners a completely different way. Their subterfuge exposed, the NRC “suddenly” found itself able to provide Mark with interim information, or at least selective portions of that information.

The NRC completed its technical analysis of Mark’s petition in March 2016 but withheld that information from him and the public for two years. The NRC would not withhold similar information from plant owners for two years. The NRC must play fair and stop being so cozy with the industry it sometimes regulates.

If how the NRC handled Mark’s petition is the agency at its best, we need a new agency. These antics are simply unacceptable.

]]>
https://allthingsnuclear.org/guest-commentary/nrc-post-fukushima/feed 1
What Does North Korea Want—and What is the US Prepared to Give? https://allthingsnuclear.org/dwright/what-does-nk-want https://allthingsnuclear.org/dwright/what-does-nk-want#respond Thu, 26 Apr 2018 16:46:44 +0000 https://allthingsnuclear.org/?p=15646 North Korea is not likely to negotiate in earnest unless it is convinced the United States is committed to the process. It is important that the administration put together a package of what it is willing to put on the table in response to Pyongyang’s steps. Read More

]]>
North Korea is not likely to negotiate in earnest unless it is convinced the United States is committed to the process. It is important that the administration put together a package of what it is willing to put on the table in response to Pyongyang’s steps.

Kim has talked about the dual goals of security and improving the economy. A key goal of early talks should be for the United States to understand what North Korea wants and what it is willing to do to get those things.

(Source: KCNA)

Kim’s first interest is likely setting up conditions that assure the survival of his regime without needing nuclear weapons. Recent press reports indicated what steps North Korea sees as important to increase its security, including:

  • stopping the inclusion of “nuclear and strategic assets” during US joint military exercises with South Korea,
  • guaranteeing that the United States will not attack North Korea with either conventional or nuclear weapons,
  • converting the armistice agreement from the Korean War into a peace treaty, and
  • normalizing diplomatic relations with the United States.

As part of normalizing relations, the United States should discuss opening a liaison office in Pyongyang, and to have North Korea do so in the United States. This step was discussed in the 1990s and was expected to occur by the end of 1998, but never happened.

As noted in Part 1 of this post, North Korea stated in 2016 that denuclearization “includes the dismantlement of nukes in South Korea and its vicinity.” The United States will need to understand what it means by “its vicinity,” and whether Pyongyang sees that as including the US air base on Guam, where nuclear-capable bombers are based, or Okinawa, where nuclear storage sites may be built as part of a new US military base there.

Non-military issues

In addition to security measures, North Korea is also looking for economic and development assistance. As in past negotiations this assistance would not all come from the United States.

One step would clearly be relaxing sanctions. A second would be to remove North Korea from the list of state sponsors of terrorism. President Bush had removed it from the list in 2008, but President Trump relisted it last November. This creates a barrier, for example, to economic assistance and getting loans from the World Bank and other international institutions.

In the past there were discussions of helping North Korea grow more of its own food through assistance with fertilizer, measures to repair and improve irrigation systems, etc. Such assistance would still be important.

In past negotiations there has also been a focus on energy assistance. Frequently that took the form of shipments of heavy fuel oil, which was chosen because it could be used to produce energy but was not highly refined enough to be useful to fuel military vehicles, etc. However, its interest is certainly broader than that. In the 1990s, North Korea was interested in assistance in developing energy technologies, including sending scientists to the National Renewable Energy Laboratory. The North could also benefit from assistance in modernizing its power grid.

In the past, North Korea has also declared the right to develop nuclear energy for peaceful uses, and is currently building a reactor that it says is intended for producing power and would not be used for military purposes. In principle, this could be done once it has rejoined the NPT and allowed the IAEA to safeguard its nuclear facilities, but given North Korea’s past action in expelling inspectors and pulling out of the NPT this is certain to be controversial.

North Korea has also been interested in assistance to improve its mining sector. Such a step could be very important since minerals are one of the main resources North Korea has to earn foreign exchange. A recent article notes that

North Korea has sizeable deposits of more than 200 different minerals, including coal, iron ore, magnesite, gold ore, zinc ore, copper ore, limestone, molybdenite, graphite and tungsten. All have the potential for the development of large-scale mines.

The United States could help establish a fund to assist North Korea in developing its mining technology and infrastructure, and could encourage private capital to help develop the mining sector. In 1993, Israel was negotiating with North Korea to stop missile sales to the Middle East, and assistance for its mining industry was an important part of the deal. Ultimately, Israel backed away from this agreement under US pressure since the United States was negotiating with North Korea over its nuclear program at the time.

Former Senators Nunn and Lugar have also proposed developing a program that would help employ and retrain scientists and engineers from North Korea’s military sector, and to provide technical and financial assistance for destroying and disposing of nuclear, chemical, and biological weapons and their delivery systems. This is similar to what was done under the successful Cooperative Threat Reduction program Nunn and Lugar developed after the breakup of the Soviet Union.

Finally, North Korea has stated that it wants to be able to use space in the ways other countries do—for communications, earth monitoring, resource exploration, weather forecasts, etc.—and has developed an incipient satellite launch capability. An indigenous satellite launch program could be acceptable sometime in the future when the international community has developed more trust in the North Korean regime, but not in the near term.

There are several approaches to negotiating an end to this program. One approach is for the international community to provide North Korea access to various kinds of satellite services and help with developing the expertise needed to use it, eliminating the need for it to own and operate its own satellites.

A second approach would be to set up a consortium that could help North Korea develop technical satellite expertise and design and build a satellite. The international community would then fund or heavily subsidize foreign launch services to compensate for North Korea’s lack of domestic launch capability. And in either case it could be useful to integrate North Korea into various international and regional space and satellite forums.

(Part 1 of this post)

]]>
https://allthingsnuclear.org/dwright/what-does-nk-want/feed 0
What Does the US Want from North Korea? https://allthingsnuclear.org/dwright/what-does-the-us-want-from-nk https://allthingsnuclear.org/dwright/what-does-the-us-want-from-nk#comments Thu, 26 Apr 2018 16:45:26 +0000 https://allthingsnuclear.org/?p=15637 President Trump is planning to meet with North Korean leader Kim Jong-Un in May or June. In preparing for the summit, the administration must be clear about what it wants from the process—both near-term and long-term. And it needs to figure out what it is willing to put on the table to get those things. Read More

]]>
President Trump is planning to meet with North Korean leader Kim Jong-Un in May or June. In preparing for the summit, the administration must be clear about what it wants from the process—both near-term and long-term. And it needs to figure out what it is willing to put on the table to get those things.

(Source: KCNA)

Beginning talks

The current situation seems to offer about as good a stage as one can imagine for talks that could lead to meaningful changes in North Korea’s nuclear and missile programs.

In particular, North Korea has said it is willing to talk about denuclearization, which is a long-standing US pre-condition for talking. Press reports in early April reported that Pyongyang had repeated its willingness to discuss denuclearization and indicated the key things it wanted in return, which are steps to increase the security of the regime that appear similar to steps the United States agreed to under the Bush administration. And it has said it would not require US forces to leave South Korea as part of such a deal.

Moreover, North Korea has said it is ending nuclear and missile tests. It has not conducted a missile test in more than four months—which is especially noteworthy after testing at a rate of nearly twice a month in 2017. A lack of testing is meaningful since it places significant limits on North Korea’s development of nuclear weapons and long-range missiles, and it can be readily verified by US satellites and seismic sensors in the region.

There is a debate about whether “denuclearization” is a realistic long-term goal of negotiations, what that term means to North Korea, and what it would take to get North Korea to give up its weapons. It seems significant, however, that in July 2016 Pyongyang stated that denuclearization means “denuclearization of the whole Korean peninsula and this includes the dismantlement of nukes in South Korea and its vicinity” but did not say it would only give up its weapons when the United States and other countries disarm, which is the position it had taken previously.

Whether or not full denuclearization of the peninsula is possible, there is a lot to be done in the near-term that would greatly benefit US and regional security and set the conditions for denuclearization.

And the administration should remember that the alternatives to diplomacy are not good: The best is a stalemate in which the United States uses the threat of retaliation to deter a North Korean strike, just as it does with Russia and China. A military strike and response by North Korea would be a disaster for the region.

Confrontation vs. Diplomacy

The first thing the administration must decide is whether it will pursue confrontation or diplomacy in this meeting.

There is a strong feeling among some in Washington that the North Korean regime is evil and that any effort to negotiate simply helps the regime—and that the United States should not be doing that. Instead these people believe the only solution is regime change in Pyongyang. They see a face-to-face meeting at best as an opportunity to confront North Korea rather than seriously negotiate.

This issue will certainly become a prominent point debated in Washington if negotiations go forward. If President Trump wants an agreement he will have to ignore these arguments, which torpedoed negotiations under the Bush administration.

Even among those in the administration who want to engage North Korea, the prevailing idea seems to be that the United States should demand that North Korea give the United States what it wants up front before Washington will reciprocate.

For example, in his recent confirmation hearing for secretary of state, Mike Pompeo said the administration would not give North Korea “rewards” until it had denuclearized “permanently, irreversibly.” Similarly, an unnamed administration official said “the US will not be making substantial concessions, such as lifting sanctions, until North Korea has substantially dismantled its nuclear programs.”

Because of the long-standing lack of trust between the two countries, North Korea has instead called for a “phased, synchronized” implementation of any deal. This is the approach adopted at the Six Party talks in 2005, when the parties agreed to move forward “commitment for commitment, action for action.” Kim presumably wants a step-by-step process that convinces him that he will not become the next Gadhafi.

These US statements may still allow Washington to offer things early on other than sanctions relief, such as taking steps to normalize relations and remove North Korea from the list of state sponsors of terrorism. If instead the administration expects North Korea to give the United States what it wants up front—and lose its negotiating leverage before the United States addresses the issues Pyongyang brings to the table—that approach will fail.

One concern is that the United States may overestimate the leverage it has, overplay its hand at the table, and lead to a failed summit. If other countries see an intransigent US approach as preventing progress on engaging North Korea and reducing the risk it poses, that could begin to create cracks in the sanctions regime, which would reduce US leverage for substantial changes.

It’s worth remembering that in the early 2000s the George W Bush administration’s confrontation policy derailed negotiations that appeared close to ending Pyongyang’s plutonium production and missile development at a time North Korea had no nuclear weapons or long-range missiles. Following that, North Korea continued these programs and today it has both.

What is North Korea up to?

Why the new tone from Pyongyang and the limits it has announced on its nuclear and missile programs?

Some suggest this is just a ploy by North Korea to buy time to produce more fissile material and missile parts, and to try to create splits between the countries currently supporting sanctions against it with the hope of getting sanctions relief without really limiting its military capabilities in a serious way.

On the other hand, it may be that Kim understands his military buildup is unsustainable and that to stay in power he needs to turn to improving the economy, as he promised when he took power. Nicholas Kristof wrote recently that “Kim has made rising living standards a hallmark of his leadership, and sanctions have threatened that pillar of his legitimacy.” Now that he appears to feel secure with his position within the ruling elite he may need to think about the middle class that appears to be emerging in North Korea.

He may have decided, as his father appeared to in the late 1990s, that opening to the world is his only chance for real economic growth. Not only are his nuclear and missile programs barriers to that opening, they are also two of the few things of significant value he has to take to the negotiating table.

That doesn’t mean he has decided to get rid of them any time soon. But if this is his thinking, then significantly limiting—and possibly eventually eliminating—these programs makes sense if he can get security assurances that convince him he doesn’t need these weapons.

To understand what it is dealing with, the United States will have to take steps that test to what extent the North is willing to accept meaningful limitations—such as accepting international inspectors to confirm that plutonium production and uranium enrichment facilities are shut down and beginning to be dismantled. This has happened before with North Korea’s nuclear facilities at Yongbyon, so there is a precedent. These steps are important both for understanding Pyongyang’s intent and for halting its nuclear program on the way to denuclearization.

Near-term goals

The best outcome for a meeting between the two leaders is that it will set broad goals for an agreement that addresses both countries’ security concerns and establishes a path to denuclearization. But as we’ve seen in the past, working out the details—especially on issues like inspections and verification—will be tricky and take time. So one goal of the first meeting should be to agree to a schedule of ongoing talks to give both countries an expectation of a continuing process, and a list of what issues will be on the table at future meetings.

Here are three things that should be near-term goals of the negotiations:

  1. Locking in a permanent ban on nuclear and missile tests, and satellite launches.

(Source: KCNA)

North Korea has announced that it is ending nuclear and missile tests and shutting down its nuclear test site. The United States should clarify the details and get it written down as a formal commitment.

While North Korea put this on the table even before negotiations began, people should not overlook its potential importance.

North Korea has now done a single test of a missile that in principle can reach all of US territory, several underground tests of an atomic bomb, and a single underground test of what was likely a hydrogen bomb. Given those tests, North Korea can say it has—in principle at least—the ability to hit the United States with a nuclear missile and therefore has a deterrent to a US military attack.

Indeed, in his New Years’ message this year, Kim said, “we achieved the goal of completing our state nuclear force in 2017,” adding that “the entire area of the US mainland is within our nuclear strike range, and the US can never start a war against me and our country.”

But North Korea does not yet have a fully tested capability to attack the United States with a long-range missile, and this matters. With only a single test of its Hwasong-15 missile on a lofted trajectory and no known successful test of a reentry vehicle on a long-range missile, additional tests are necessary to gain that practical capability. Similarly, after only a single test of a hydrogen bomb, it is very unlikely North Korea has a design that is small and light enough to launch on a missile, and it has little information about the reliability of the design.

This means that stopping additional nuclear and missile tests is important and meaningful. And since the United States can verify that no tests are occurring, it will know if North Korea is abiding by the agreement.

There are reasons why Kim may be happy to stop testing long-range missiles at this point. For one thing, while his single test of the Hwasong-15 missile was successful, there is no guarantee that a second test would be. A failure would undercut Kim’s claim of having a missile capability against the United States.

Moreover, gaining confidence in the missile performance would require a series of successful flight tests. The rapid increase in the range of the tested missiles during 2017 may have been possible because key components were acquired from Russia. If so, the North may be limited in how many missiles it can actually build—either to test or put in an arsenal.

While I have argued that developing a working reentry vehicle is not likely to be a technical barrier for North Korea, it has not yet demonstrated that it has one in hand for a long-range missile. Stopping further missile tests would keep it that way.

The two countries should clarify what missiles the flight ban applies to. The United States should press for it to include all missiles—ballistic and cruise—that would have a range over 300 km with a 500 kg payload, which is the MTCR limit. It would therefore apply to missiles that could reach Japan. South Korea has developed ballistic missiles with ranges up to 800 km and cruise missiles with ranges up to 1,500 km, and this flight ban would apply to the South as well. That would require South Korea’s agreement to this limit.

The United States should make clear that the ban also applies to satellite launchers. Because the technologies for satellite launchers can be used to develop long-range missiles, stopping this development is an important part of ending its missile program. Getting the North to agree to give up that program, given the civil benefits of a satellite program, is likely to require the US to arrange for the international community to provide access to space launch or satellite services in place of a domestic space launch program.

A longer term step would be eliminating all missiles on the peninsula that fall under the flight ban. Verifying elimination would be more difficult than verifying a flight ban, but was discussed in the negotiations with North Korea under both Clinton and Bush, and verification was put in place as part of the Intermediate Nuclear Forces (INF) Treaty, which eliminated all US and Russia ground-based missiles with ranges between 500 and 5,500 km.

Following that, the next step could be to eliminate all missiles, as well as the artillery North Korea has aimed at Seoul, as part of a broader agreement limiting conventional forces.

  1. A freeze on the production of separated plutonium and highly enriched uranium, leading to a ban

Yongbyon reactor (Source: US Senate)

A second near-term goal of negotiations should be an agreement to shut down North Korea’s nuclear reactors, which are the source of its plutonium, and have inspectors on the ground to ensure it does not extract plutonium from fuel rods that have been removed from the reactors. North Korea agreed to both steps in the 1994 Agreed Framework and verifiably did so until the Framework collapsed in 2002.

The agreement should also put international inspectors at North Korea’s known enrichment facility to verify that it is not being operated, and allow challenge inspections of other sites that it might suspect are being used for enrichment.

Getting these agreements would not be unprecedented. During the 2005 negotiations, Pyongyang agreed to “abandoning all nuclear weapons and existing nuclear programs and returning, at an early date, to the Treaty on the Nonproliferation of Nuclear Weapons and to IAEA safeguards.” Those negotiations eventually stalled over disagreements on verification measures and inspections, which were unresolved when the Bush administration left office.

The agreement should also require Pyongyang to preserve information that in the future would allow the IAEA to construct a history of its past nuclear activities. This would allow the IAEA to determine how much fissile material North Korea had produced—and whether it was all accounted for.

As part of the Six Party talks under George W. Bush in 2008, North Korea shut down its reactor at Yongbyon and provided 18,000 documents about its plutonium production, so there is a precedent for this as well.

  1. A ban on the sale or transfer of missile or nuclear technology, or technical assistance

As part of a deal, North Korea should agree to a ban on the sale or transfer of missile or nuclear technology to other countries or groups, and a ban on providing technical assistance on these systems. Such a ban would require agreement on transparency measures to help provide confidence that such activities were not taking place. In a recent speech, Kim stated:

… the DPRK will never use nuclear weapons nor transfer nuclear weapons or nuclear technology under any circumstances unless there are nuclear threats and nuclear provocations against the DPRK.

So this could be a starting point for a discussion of these issues.

In the longer term, in addition to talking about denuclearization, the United States should focus on getting rid of North Korea’s chemical and biological weapons programs, and put restrictions on its conventional weapons. The latter would have to include restrictions on South Korean conventional weapons as well.

(The second part of this post will discuss what North Korea is likely to want from the talks.)

]]>
https://allthingsnuclear.org/dwright/what-does-the-us-want-from-nk/feed 3
The “Race” to Resolve the Boiling Water Reactor Safety Limit Problem https://allthingsnuclear.org/dlochbaum/the-race-to-resolve-the-boiling-water-reactor-safety-limit-problem https://allthingsnuclear.org/dlochbaum/the-race-to-resolve-the-boiling-water-reactor-safety-limit-problem#respond Tue, 24 Apr 2018 10:00:58 +0000 https://allthingsnuclear.org/?p=15622 General Electric (GE) informed the Nuclear Regulatory Commission (NRC) in March 2005 that its computer analyses of a depressurization event for boiling water reactors (BWRs) non-conservatively assumed the transient would be terminated by the automatic trips of the main turbine and reactor on high water level in the reactor vessel. Read More

]]>
General Electric (GE) informed the Nuclear Regulatory Commission (NRC) in March 2005 that its computer analyses of a depressurization event for boiling water reactors (BWRs) non-conservatively assumed the transient would be terminated by the automatic trips of the main turbine and reactor on high water level in the reactor vessel. GE’s updated computer studies revealed that one of four BWR safety limits could be violated before another automatic response terminated the event.

Over the ensuring decade-plus, owners of 28 of the 34 BWRs operating in the US applied for and received the NRC’s permission to fix the problem. But it’s not clear why the NRC allowed this known safety problem, which could allow nuclear fuel to become damaged, to linger for so long or why the other six BWRs have yet to resolve the problem. UCS has asked the NRC’s Inspector General to look into why and how the NRC tolerated this safety problem affecting so many reactors for so long.

BWR Transient Analyses

The depressurization transient in question is the “pressure regulator fails open” (PRFO) event. For BWRs, the pressure regulator positions the bypass valves (BPV in Figure 1) and control valves (CV) for the main turbine as necessary to maintain a constant pressure at the turbine inlet.

When the reactor is shut down or operating at low power, the control valves are fully closed and the bypass valves are partially opened as necessary to maintain the specified pressure. When the turbine/generator is placed online, the bypass valves are closed and the control valves are partially opened to maintain the specified inlet pressure. As the operators increase the power level of the reactor and send more steam towards the turbine, the pressure regulator senses this change and opens the control valves wider to accept the higher steam flow and maintain the constant inlet pressure.

Fig. 1 (Source: Nuclear Regulatory Commission, annotated by UCS)

If the sensor monitoring turbine inlet pressure provides a false high value to the pressure regulator or an electronic circuit card within the regulator fails, the pressure regulator can send signals that fully open the bypass valves and the control valves. This is called a “pressure regulator fails open” (PRFO) event. The pressure inside the reactor vessel rapidly decreases as the opened bypass and control valves accept more steam flow. Similar to how the fluid inside a shaken bottle of soda rises to and out the top when the cap is removed (but for different physical reasons), the water level inside the BWR vessel rises as the pressure decreases.

The water level is normally about 10 feet above the top of the reactor core. When the water level rises about 2 feet above normal, sensors will automatically trip the main turbine. When the reactor power level is above about 30 percent of full power, the turbine trip will trigger the automatic shut down of the reactor. The control rods will fully insert into the reactor core within a handful of seconds to stop the nuclear chain reaction and terminate the PRFO event.

The Race to Automatic Reactor Shut Down

The reactor depressurization during a PRFO event above 30 percent power actually starts two races to automatically shut down the reactor. One race ends when high vessel level trips the turbine which in turn trips the reactor. The second race is when low pressure in the reactor vessel triggers the automatic closure of the main steam isolation valves (MSIV in Figure 1). As soon as sensors detect the MSIVs closing, the reactor is automatically shut down.

BWRs do not actually stage PRFO events to see what parameter wins the reactor shut down race. Instead, computer analyses are performed of postulated PRFO events. The computer codes initially used by GE had the turbine trip on high water level winning the race. GE’s latest code shows MSIV closure on low reactor vessel pressure winning the race.

The New Race Winner and the Old Race Loser

The computer analyses are performed for reasons other than picking the winner of the reactor shut down race. The analyses are performed to verify that regulatory requirements will be met. When the winner of the PRFO event reactor shut down race was correctly determined, the computer analyses showed that one of four BWR safety limits could be violated.

Figure 2 shows the four safety limits for typical BWRs. The safety limits are contained within the technical specifications issued by the NRC as appendices to reactor operating licenses. GE’s latest computer analyses of the PRFO event revealed that the reactor pressure could decrease below 785 pounds per square inch gauge (psig) before the reactor power level dropped below 25 percent—thus violating Safety Limit 2.1.1.1. The earlier computer analyses non-conservatively assumed that reactor shut down would be triggered by high water level, reducing reactor power level below 25 percent before the reactor pressure decreased below 785 psig.

Fig. 2 (Source: Nuclear Regulatory Commission)

Safety Limit 2.1.1.1 supports Safety Limit 2.1.1.2. Safety Limit 2.1.1.2 requires the Minimum Critical Power Ratio (MCPR) limit to be met whenever reactor pressure is above 785 psig and the flow rate trough the reactor core is above 10 percent of rated flow. The MCPR limit protects the fuel from being damaged by insufficient cooling during transients, including PRFO events. The MCPR limit keeps the power output from individual fuel bundles from exceeding the amount that can be carried away during transients.

As in picking reactor shut down race winners, BWRs do not slowly increase fuel bundle powers until damage begins, then back it down a smidgen or two. Computer analyses of transients also model fuel performance. The results from the computer analyses establish MCPR limits that guard against fuel damage during transients.

The computer analyses examine transients from a wide, but not infinite, range of operating conditions. Safety Limit 2.1.1.1 defines the boundaries for some of the transient analyses. Because Safety Limit 2.1.1.1 does not permit the reactor power level to exceed 25 percent when the reactor vessel pressure is less than 785 psig, the computer analyses performed to establish the MCPR limit in Safety Limit 2.1.1.2 do not include an analysis of a PRFO event for high power/low pressure conditions.

Thus, the problem reported by GE in March 2005 was not that a PRFO event could violate Safety Limit 2.1.1.1 and result in damaged fuel. Rather, the problem was that if Safety Limit 2.1.1.1 was violated, the MCPR limit established in Safety Limit 2.1.1.2 to protect against fuel damage could no longer be relied upon. Fuel damage may, or may not occur, as a result of a PRFO event. Maybe, maybe not is not prudent risk management.

The Race to Resolve the BWR Safety Limit Problem

The technical specifications allow up to two hours to remedy a MCPR limit violation; otherwise the reactor power level must be reduced to less than 25 percent within the next four hours. This short time frame implies that the race to resolve the BWR Safety Limit problem would be a dash rather than a marathon.

The nuclear industry submitted a request to the NRC on July 18, 2006, asking that the agency merely revise the bases for the BWR technical specifications to allow safety limits to be momentarily violated. The NRC denied this request on August 27, 2007, on grounds that it was essentially illegal and unsafe:

Standard Technical Specifications, Section 5.5.14(b)(1), “Technical Specifications (TS) Bases Control Program,” states that licensees may make changes to Bases without prior NRC approval, provided the changes do not involve a change in the TS incorporated in the license. The proposed change to the TS Bases has the effect of relaxing, and hence, changing, the TS Safety Limit. An exception to a stated TS safety limit must be made in the TS and not in the TS Bases. In addition,  a potential exists that the requested change in the TS Bases could have an adverse effect on maintaining the reactor core safety limits specified in the Technical Specifications, and thus, may result in violation of the stated requirements. Therefore, from a regulatory standpoint, the proposed change to the TS Bases is not acceptable. [emphasis added]

and

… the staff is concerned that in some depressurization events which occur at or near full power, there may be enough bundle stored energy to cause some fuel damage. If a reactor scram does not occur automatically, the operator may have insufficient time to recognize the condition and to take the appropriate actions to bring the reactor to a safe configuration. [emphasis added]

In April 2012, the nuclear industry abandoned efforts to convince the NRC to hand wave away the BWR safety limit problem and recommended that owners submit license amendment requests to the NRC to really and truly resolve the problem.

Forget the Tortoise and the Hare—the Snail “Wins” the Race

On December 31, 2012, nearly ten years after GE reported the problem, the owner of two BWRs submitted a license amendment request to the NRC seeking to resolve the problem. The NRC issued the amendment on December 8, 2014. Table 1 shows the “race” to fix this problem at the 34 BWRs operating in the US.

Table 1: License Amendments to Resolve BWR Safety Limit Problem
Reactor License Amendment Request License Amendment Original Reactor  Pressure Revised Reactor  Pressure
Susquehanna Units 1 and 2 12/31/2012 12/08/2014 785 psig 557 psig
Monticello 03/11/2013 11/25/2014 785 psig 686 psig
Pilgrim 04/05/2013 03/12/2015 785 psig 685 psig
River Bend 05/28/2013 12/11/2014 785 psig 685 psig
FitzPatrick 10/08/2013 02/09/2015 785 psig 685 psig
Hatch Units 1 and 2 03/24/2014 10/20/2014 785 psig 685 psig
Browns Ferry Units 1, 2, and 3 12/11/2014 12/16/2015 785 psig 585 psig
Duane Arnold 08/06/2015 08/18/2016 785 psig 686 psig
Clinton 08/18/2015 05/11/2016 785 psig 700 psia
Dresden Units 2 and 3 08/18/2015 05/11/2016 785 psig 685 psig
Quad Cities Units 1 and 2 08/18/2015 05/11/2016 785 psig 685 psig
LaSalle Units 1 and 2 11/19/2015 08/23/2016 785 psig 700 psia
Peach Bottom Units 2 and 3 12/15/2015 04/27/2016 785 psig 700 psia
Limerick Units 1 and 2 01/15/2016 11/21/2016 785 psig 700 psia
Columbia Generating Station 07/12/2016 06/27/2017 785 psig 686 psig
Nine Mile Point Unit 1 08/01/2016 11/29/2016 785 psig 700 psia
Oyster Creek 08/01/2016 11/29/2016 785 psig 700 psia
Perry 11/01/2016 06/19/2017 785 psig 686 psig
Nine Mile Point Unit 2 12/13/2016 10/31/2017 785 psig 700 psia
Brunswick Units 1 and 2 None found None found 785 psig Not revised
Cooper None found None found 785 psig Not revised
Fermi Unit 2 None found None found 785 psig Not revised
Grand Gulf None found None found 785 psig Not revised
Hope Creek None found None found 785 psig Not revised

 

UCS Perspective

BWR Safety Limits 2.1.1.1 and 2.1.1.2 provide reasonable assurance that nuclear fuel will not be damaged during design bases transients. In March 2005, GE notified the NRC that a computer analysis glitch undermined that assurance.

The technical specifications issued by the NRC allow BWRs to operate above 25 percent power for up to six hours when the MCPR limit is violated. GE’s report did not reveal the MCPR limit to be violated at any BWR; but it stated that the computer methods used to establish the MCPR limits were flawed.

There are only four BWR safety limits. After learning that one of the few BWR safety limits could be violated and determining that fuel could be damaged as a result, the NRC monitored the glacial pace of the resolution of this safety problem. And six of the nation’s BWRs have not yet taken the cure. Two of those BWRs (Brunswick Units 1 and 2) do not have GE fuel and thus may not be susceptible to this problem. But Cooper, Fermi Unit 2, and Hope Creek have GE fuel. It is not clear why their owners have not yet implemented the solution.

The NRC is currently examining how to implement transformational changes to become able to fast track safety innovations. I hope those efforts enable the NRC to resolve safety problems in less than a decade; way, way less than a decade. Races to resolve reactor safety problems must become sprints and no longer leisurely paced strolls. Americans deserve better.

UCS asked the NRC’s Inspector General to look into how the NRC mis-handled the resolution of the BWR safety limit problem. The agency can, and must, do better and the Inspector General can help the agency improve.

]]>
https://allthingsnuclear.org/dlochbaum/the-race-to-resolve-the-boiling-water-reactor-safety-limit-problem/feed 0
Japan’s Nuclear Hawks Could Block US-North Korean Agreement on Denuclearization https://allthingsnuclear.org/gkulacki/japans-nuclear-hawks-could-block-us-north-korean-agreement-on-denuclearization https://allthingsnuclear.org/gkulacki/japans-nuclear-hawks-could-block-us-north-korean-agreement-on-denuclearization#comments Sun, 22 Apr 2018 12:46:13 +0000 https://allthingsnuclear.org/?p=15595 Momentum has been building for a productive meeting between President Trump and Kim Jung-un that could lead to an agreement on North Korean denuclearization. But after speaking with Japanese Prime Minister Shinzo Abe, Trump warned the world that he might cancel or walk out of the meeting if “it is not going to be fruitful.”

US President Donald Trump and Japanese Prime Minister Shinzo Abe shake hands at a press conference concluding two days of talks.

Read More
]]>
Momentum has been building for a productive meeting between President Trump and Kim Jung-un that could lead to an agreement on North Korean denuclearization. But after speaking with Japanese Prime Minister Shinzo Abe, Trump warned the world that he might cancel or walk out of the meeting if “it is not going to be fruitful.”

US President Donald Trump and Japanese Prime Minister Shinzo Abe shake hands at a press conference concluding two days of talks.

What did Mr. Abe tell Mr. Trump that precipitated the warning?  The prime minister may have reminded the president that his Nuclear Posture Review, which the Japanese Foreign Ministry strongly endorsed, included US promises to increase the role of US nuclear weapons in Asia. The ministry could be trying to prevent any weakening of those promises from becoming part of an agreement with North Korea on denuclearization.

Defining Denuclearization

US and foreign observers have disagreed about the meaning of the term. But North Korea has made it clear that it considers denuclearization a mutual responsibility. The United States has acknowledged reciprocal denuclearization obligations in the past, but they were limited to the Korean land mass.

US negotiators should be aware that North Korean conditions for a credible security guarantee may include a slightly broader definition of US denuclearization obligations and some additional US relaxation of its nuclear posture in Asia. In July 2016 Pyongyang stated that denuclearization means “denuclearization of the whole Korean peninsula and this includes the dismantlement of nukes in South Korea and its vicinity.”

This would not be an unreasonable request. Nuclear-capable US aircraft and submarines patrolling in the region are just as threatening to North Korea as US nuclear weapons stationed on the peninsula itself. The United States has used displays of regional nuclear capabilities, such as nuclear-capable bombers deployed to Guam, to threaten North Korea in the past. North Korean threats to attack Guam with medium range missiles were a response to those displays, and a prominent part of the tense fall run-up to this spring’s negotiations.

If North Korea were to ask for a broadening of reciprocal US obligations to denuclearize the region as a condition for relinquishing its nuclear capabilities, the United States may have to walk back some aspects of the extended nuclear deterrence commitments it made to Japan during the Obama administration and cancel plans to further enhance those commitments—plans included in the Trump administration’s Nuclear Posture Review.

Japanese Nuclear Preferences

On 25 February 2009 Minister Takeo Akiba, who headed the political section of Japan’s embassy in Washington, presented a document to a US congressional commission stating President Obama assured Prime Minister Aso, at a meeting in Washington the day before, that the United States would honor the Japanese Foreign Ministry’s request to make nuclear deterrence “the core of Japan–US security arrangements.” The document contained a list of US nuclear weapons capabilities the ministry believed were needed to make that assurance credible.

The list included US nuclear weapons that could be deployed in the region, including nuclear-capable cruise missiles on US attack submarines that patrol in Asia and nuclear-capable aircraft on the island of Guam. A conversation about the list between Mr. Akiba and commission co-chair James Schlesinger included consideration of deploying US nuclear weapons on US military bases on the Japanese island of Okinawa. Mr. Akiba, who is now Japan’s Vice Minister of Foreign Affairs, explained that domestic political conditions in Japan made deployment in Okinawa problematic. But he also noted that there is a constituency within Japan’s Foreign Ministry that supports deployment and he appeared to agree to construct storage facilities for US nuclear weapons in Okinawa in anticipation of eventual deployment when political conditions in Japan change.

The Obama administration permanently retired the nuclear-capable cruise missile the United States once deployed on US attack submarines patrolling in Asia. US President George H.W. Bush removed them from service in 1992. But Obama reportedly agreed to compensate for the loss of this capability by making US nuclear weapons available for deployment in Asia aboard dual-capable aircraft. The Trump administration, noting the importance of the capability to deploy US nuclear weapons in Asia, plans to build a new submarine-launched nuclear-capable cruise missile to replace the one his predecessors removed from service and retired.

Reciprocal Verification

The United States expects North Korea to agree to verifiable measures to halt the development of new nuclear weapons, eliminate its existing nuclear weapons and dismantle its ability to reconstitute its nuclear weapons program in the future. It is only reasonable to expect that North Korea would require credible assurances that the United States will not introduce or threaten to introduce US nuclear weapons into the region in the future.

The United States could agree to such a request without diminishing its ability to provide extended nuclear deterrence to its Asian allies with its strategic nuclear forces, which do not need to enter the region to be effective. But it would have to forgo whatever psychological advantages it presumes to obtain by maintaining the ability and expressing the will to deploy US tactical nuclear weapons in Asia if deemed necessary.

South Korea seems to be prepared to make this concession in the interest of avoiding a war with the North. But Trump’s unexpected threat to cancel or walk out of a summit meeting with Kim Jung-un, announced while standing next to Japan’s prime minister after two days of meetings, suggests Abe may have told the US president that exchanging the option to deploy US tactical nuclear weapons in Asia for a deal on denuclearization with North Korea would not be “fruitful.”

]]>
https://allthingsnuclear.org/gkulacki/japans-nuclear-hawks-could-block-us-north-korean-agreement-on-denuclearization/feed 1
Commendable Nuclear Safety Catch at the Susquehanna Nuclear Plant https://allthingsnuclear.org/dlochbaum/safety-catch-at-susquehanna https://allthingsnuclear.org/dlochbaum/safety-catch-at-susquehanna#comments Mon, 16 Apr 2018 14:42:27 +0000 https://allthingsnuclear.org/?p=15589 The owner of the two boiling water reactors (BWRs) at the Susquehanna Steam Electric Station in northeastern Pennsylvania notified the Nuclear Regulatory Commission (NRC) on April 2, 2018, that workers’ mistakes rendered an emergency core cooling system on Unit 1 vulnerable to being disabled by an earthquake at the same time that another emergency core cooling system was out of service for work on its power supply system. Read More

]]>
The owner of the two boiling water reactors (BWRs) at the Susquehanna Steam Electric Station in northeastern Pennsylvania notified the Nuclear Regulatory Commission (NRC) on April 2, 2018, that workers’ mistakes rendered an emergency core cooling system on Unit 1 vulnerable to being disabled by an earthquake at the same time that another emergency core cooling system was out of service for work on its power supply system. This is good news—not in having two safety systems impaired while the reactor operated, but in how quickly the problem was detected and corrected.

The Emergency Core Cooling Systems

Susquehanna Unit 1 is a model BWR/4 reactor with a Mark II containment design that was placed into commercial operation in June 1983. In case of an accident that drains cooling water from the reactor vessel, Unit 1 is equipped with an array of emergency core cooling system (ECCS) pumps that will automatically start and provide makeup water. The ECCS include one steam-driven high pressure coolant injection (HPCI) pump, four motor-driven low pressure coolant injection (LPCI) pumps, and more motor-driven core spray (CS) pumps. The LPCI and CS pumps are split into two divisions of two LPCI pumps and two CS pumps each. Each division is powered from separate electrical buses, backed by separate emergency diesel generators, to increase the chances that enough pumps survive whatever challenge is experienced to provide adequate makeup cooling water flow for the reactor core.

The Situation

During the early afternoon of December 1, 2017, workers moved pipe sections into the room housing the Division II core spray pumps and staged this material on the floor as close as six inches from one of the two air conditioning units for the room.

At 7:48 am on December 2, the power supply to the Division II low pressure coolant injection pumps was removed from service to enable its voltage regulator to be replaced.

The Problem

At 10:30 am on December 3, an operator noticed that the materials staged in the core spray pump room were not seismically restrained and were close to one of the room’s air conditioning unit. The Operations department conservatively assumed that an earthquake could case the pipe sections to move into and damage the air conditioning unit. If that occurred, the heat from the running core spray pump motors could warm the room above the temperature that electrical equipment was qualified to endure. The Operations department declared the Division II core spray pumps inoperable due to their potential loss in event of an earthquake.

The Unit 1 operation license allowed the Division II low pressure coolant injection pumps to be out of service for up to 7 days while the reactor continued operating. This allowed outage time relied on other ECCS pumps being available in case an accident happened. The discovery that the Division II core spray pumps were also inoperable undermined that reliance. The operating license for Unit 1 required the reactor to be shut down within 7 hours with both the Division II low pressure coolant injection and core spray pumps inoperable.

The Solution

At 1:35 pm on December 3, the Division II low pressure coolant injection pumps were restored to operable following replacement of the voltage regulator on their power supply. Their restoration ended the need for the reactor to be shut down and returned the unit to the need to restore the Division II core spray pumps to service within 5 days (the 7-day clock started on December 1).

Around 4:00 pm on December 3, workers completed the removal of the pipe sections from the Division II core spray pump room. Doing so ended the need to shut down the reactor as all ECCS pumps were restored to service.

The Armchair Viewpoint

The Engineering department analyzed the temperature in the Division II core spray pump room with both motor-driven core spray pumps running and only one of two air conditioning units in the room operating. The second air conditioning unit was assumed not to be running due to damage from the pipe sections hitting it during an earthquake. The engineering analysis concluded that the room temperature would have remained below the temperatures used to qualify safety components in the room and that the core spray pumps would have performed their safety function successfully.

UCS Perspective

The staging of the replacement pipe sections without seismic restraints in the Division II core spray pump rooms near its air conditioning unit could have resulted in an air conditioning unit becoming damaged during an earthquake. That potential vulnerability was not recognized the next day when the Division II low pressure coolant injection pumps were taken out of service for maintenance to their power supply. The defense-in-depth approach to nuclear safety gets undermined when multiple layers are missing and/or impaired concurrently.

It would have been better had the pipe sections not been staged improperly or had that mistake been identified before it was compounded by the intentional disabling of additional ECCS pumps the next day. But dozens of activities are ongoing each and every day at a nuclear power plant. And materials temporary stored in the core spray pump room—a confined area infrequently accessed by workers on a daily basis—made detection of their improper configuration less than readily evident.

The mistake was identified by the Operations department less than two days after it was made and a day after it was compounded by taking other ECCS pumps out of service. It would have been easy not to have discovered the subtle mistake, but it was found. Once found, it would have been easy to presume that the core spray pumps would have functioned despite the potential loss of one of two air conditioning units in the room. But the Operations department lacked an analysis to support that presumption and declared the pumps inoperable. That conservative call accelerated the solution to the problem. Within about 185 minutes, the low pressure coolant injection pumps were restored to service. And within 330 minutes, the pipe sections were removed to eliminate the potential hazard to the air conditioning unit in the core spray pump room. The Operations department handled this matter very well. The Operations department handled this matter very well.

Defense-in-depth is frequently discussed in terms of equipment—two redundant pumps provided when only one needs to run for the necessary safety function to be fulfilled. This case illustrates how defense-in-depth also has an important role to play in human performance reliability. The Maintenance department placed the pipe sections in the core spray pump room. They should have stored the material properly, but failed to do so. The Operations department caught the mistake and caused it to be promptly remedied. And the Engineering department reviewed the mistake to determine its safety significance.

This event also reveals an unintended consequence from defense-in-depth applied to human performance reliability—when the first defense-in-depth layer succeeds, backup layers are not tested. Here, the first layer failed but the second and third layers came through. The next best thing to perfection is having a highly reliable first layer backed by a highly reliable second layer backed by a highly reliable third layer and so on.

]]>
https://allthingsnuclear.org/dlochbaum/safety-catch-at-susquehanna/feed 1
Nuclear Regulatory Commission SAGging? https://allthingsnuclear.org/dlochbaum/nrc-sagging https://allthingsnuclear.org/dlochbaum/nrc-sagging#respond Thu, 12 Apr 2018 17:21:02 +0000 https://allthingsnuclear.org/?p=15582 The Screen Actors Guild (SAG) is part of a labor union that represents nearly 160,000 actors and others in America. I don’t know how many NRC senior managers are SAG members, but with more and more individuals acting as senior managers for longer and longer periods, SAG may need to open an office in Rockville, Maryland where NRC is headquartered. Read More

]]>
The Screen Actors Guild (SAG) is part of a labor union that represents nearly 160,000 actors and others in America. I don’t know how many NRC senior managers are SAG members, but with more and more individuals acting as senior managers for longer and longer periods, SAG may need to open an office in Rockville, Maryland where NRC is headquartered.

Figure 1 shows the NRC’s organization chart as of March 1, 2018. At the top are the five Commissioners, or rather the three Commissioners because two Commission positions have been vacant for over a year. Below the Commissioners are the 29 senior NRC managers. Of those 29 senior managers, the seven managers circled in red are only acting in those roles. Some have been acting at it for a long time. Fred Brown has been acting as the Director of the Office of New Reactors for over a year while Brian Holian has been acting as the Director of the Office of Nuclear Reactor Regulation since July 1, 2017. And Victor McCree, the NRC’s Executive Director for Operations (EDO), announced he will be retiring on June 30, 2018. The casting calls for an EDO actor have not yet been announced.

Fig. 1  Red boxes indicate acting or missing managers. (Source: NRC annotated by UCS)

Why Does it Matter?

Who commands more respect:

  • A full-time teacher or a substitute?
  • A real doctor or someone who stayed at Holiday Inn Express last night?
  • A parent or a babysitter?
  • A sheriff or a mall cop (Paul Blart excepted)?
  • A bona fide manager or an acting manager?

An acting manager can tackle the job as if it is a permanent one. But will she or he truly expend as much effort on long term tasks as someone who will be in that same job when those tasks are conducted?

Even if the acting manager performs the job as fully and capably as someone in the position for real, will her or his subordinates really raise longer term matters or will they simply wait until the real boss takes over?

A non-acting manager “owns” the job and can devote all her or his skills and attention to every aspect of that job. And staff can follow non-acting leaders without being distracted by the temptation to tolerate supervision until the real boss reports for duty.

What Does It Take to Stop the Acting?

The President nominates and the Senate confirms NRC Commissioners. So, the two empty Commissioner seats are up to the President and Senate to fill—you know, the folks unable to pass real budgets and who rely instead on serial “acting” budgetary measures. The other 29 positions on Figure 1 can be filled by the NRC itself without Presidential or Congressional involvement.

The Commission, or a majority thereof, fill the positions explicitly defined in the Atomic Energy Act. These positions include the EDO and the Directors of the Office of New Reactors and Nuclear Reactor Regulation. The EDO fills the remaining positions. For example, the NRC announced on January 2, 2018, that K. Steven West had been appointed Regional Administrator for Region III, replacing Cynthia D. Pederson who retired on December 30, 2017 (three days earlier).

Mr. West had been the Acting Director of the Office of Nuclear Security and Incident Response since July 2017 when Brian Holian became the Acting Director of the Office of Nuclear Reactor Regulation. After Mr. West got his permanent assignment, Brian McDermott was named to become the new Acting Director of NSIR. Since Mr. McDermott filled in for Acting Director West who was filling in for real Director Holian, perhaps Mr. McDermott is Acting Acting Director of NSIR.

UCS Perspective

Despite how many NRC senior managers have been acting at their positions for so long, they should probably not become SAG members. SAG represents actors and others in the entertainment industry. The NRC’s musical chairs is neither entertaining to play nor to watch.

The NRC filled Ms. Pederson’s position as Regional Administrator within three days of her retirement with a permanent, not Acting, Regional Administrator. So, the NRC can fill senior management positions expeditiously without needing actors. Despite this proven ability, 24 percent of the NRC’s top 29 management positions are filled by actors. So, the NRC can do better but has chosen—for reasons unknown—not to do so.

The NRC needs to stop acting so much, Otherwise, will the last non-actor please turn out the lights on the way out the door.

]]>
https://allthingsnuclear.org/dlochbaum/nrc-sagging/feed 0