UCS Blog - All Things Nuclear (text only)

China Not an Obstacle to US Summit with North Korea

Last fall, as North Korea raced to demonstrate it could strike the United States with a nuclear-armed missile, the Chinese government acceded to strict international economic sanctions it previously resisted. This spring, after North Korea declared it had achieved its goal and would stop further testing, the Chinese government acceded to North Korean requests for greater engagement, including high-profile meetings between Xi Jinping and Kim Jong-un.

President Trump, along with many US officials and observers, praised China’s willingness to sign on to tougher sanctions. But they greeted China’s positive response to North Korea’s testing freeze with a mix of skepticism and suspicion. Trump suggested his Chinese counterpart was playing geopolitical poker with the summit in Singapore. US observers wondered whether China felt threatened by the summit and intentionally undermined it.

That’s unlikely.

Chinese President Xi Jinping (right) and North Korean leader Kim Jong-un walk the beach in Dalian, China during their recent May meeting.

China consistently advances two oft-stated objectives. The first is to prevent a war on the Korean peninsula. The second is to maintain political stability within North Korea. It accepted strict international sanctions in order to decrease the risk of a US military attack. It agreed to greater engagement with North Korea to sure up the government in Pyongyang. The prospective summit meeting advances both Chinese objectives. Should it fail to occur, the risk of a US military attack will increase. And China will face unwanted US pressure for new and potentially destabilizing economic sanctions.

China’s Current Successes

Throughout the fall, as North Korea kept testing and the United States kept piling on sanctions, China pushed for a freeze on North Korea’s nuclear weapons program, a freeze on US military exercises and direct talks between the United States and North Korea.

As US threats to attack North Korea were elevated in the US press, Kim used his 2018 New Year’s address to announce that the goal of developing a nuclear-armed missile that could reach the United States had been accomplished. At the same time, the North Korean leader extended an olive branch to South Korea.

South Korean President Moon Jae-in seized the opening and the two Koreas agreed to cooperate in hosting the Winter Olympic games in PyeongChang, which were held in mid-February and reversed the downward spiral of counterproductive rhetoric and behavior. The United States cooperated by postponing regularly scheduled annual military exercises with South Korea during the games. Kim received a high-level South Korean delegation in early March and agreed to meet with South Korean President Moon Jae-in. The South Korean envoys then told the United States Kim was open to discussing denuclearization.  President Trump quickly agreed to meet with Kim and the US military scaled back the postponed military exercises.

Chinese President Xi Jinping spoke with President Trump by phone the day after he agreed to meet with Kim. The Chinese press reported that Xi praised Trump for his “enthusiastic embrace of a political solution” to the North Korean nuclear problem and encouraged Trump to hold the meeting as soon as possible. Xi also expressed the hope that all concerned parties “could discharge a little more good will” and “avoid doing anything that might interfere with the continuing relaxation of tensions.” China’s president did not sound like he was trying to downplay or undermine bilateral US-North Korean talks the Chinese government had been publicly recommending for decades.

Xi Jinping, unlike his predecessors, did not meet with the North Korean leadership during his first term in office. US and Chinese observers opined about the deterioration of the relationship and a possible shift in Chinese foreign policy. China’s massive state propaganda apparatus put that discussion to bed after Kim traveled to Beijing in late March. Ever since, China’s state media has gone overboard to emphasize the traditional fraternal relationship between the two communist nations.

A week before his late-April summit with South Korean President Moon Jae-in, Kim unilaterally announced a halt to nuclear and missile tests, noting they were no longer needed. Kim also declared the nation was moving into a new stage of history focused on economic development.

It is difficult to know whether Kim’s meeting with Xi was responsible for the late-April announcement, but China appears to have received the North Korean freeze it requested during the height of tensions in the fall. Chinese state media reported that during Xi’s second meeting with Kim in the Chinese city of Dalian in early May, the North Korean leader told Xi that “significant progress in the situation on the Korean peninsula” was the product of their “historic” first meeting. Xi responded by emphasizing the following “four mutually agreed upon principles of a new era in China-North Korean relations.”

  • That the traditional friendship between North Korea and China was a shared precious treasure.
  • That because China and North Korea were both socialist nations their relationship had very important strategic significance requiring strengthened unity, cooperation and exchange.
  • That high-level exchanges had an irreplaceably important influence in building bilateral relations.
  • That consolidating the foundation of popular friendship was an important avenue for advancing the development of China-North Korea relations.

The fourth principle left many Chinese with the impression that a productive summit between North Korea and the United States would precipitate a regional economic boom. Chinese expectations for success were so high that articles on opportunities in the North Korean real estate market circulated in the press.

All of these developments are inconsistent with the suggestion that China is trying to undermine a successful summit between North Korea and the United States.

China’s Hopes for the Future 

Many Chinese look at North Korea through the lens of their own history. Their hope is that North Korea will follow China’s example and gradually reform its economy. As the process of economic reform unfolds, regional anxieties about provocative and violent North Korean behavior should recede, and North Korean concerns about its security should become less pressing.

Most Chinese nuclear arms control experts tell us that as long as those security concerns persist, North Korea is unlikely to agree to denuclearize. But they do believe that now that the North Korean leadership thinks it has demonstrated the potential to retaliate with a nuclear weapon it would be willing to freeze its program in exchange for some loosening of the severe economic sanctions constraining its economy.

The question for the United States, North Korea’s other neighbors and the international community is whether that’s a bargain they are willing to make.

Yesterday, after North Korea responded constructively to President Trump’s suggestion that the time for a summit was not ripe, the Chinese Foreign Ministry told reporters that China was “paying attention to the twists and turns in the preparations for the summit,” suggesting the Chinese leadership was still expecting it would eventually take place. Moreover, ministry spokesperson Lu Kang emphasized, “The Chinese government’s position on the problems on the Korean peninsula is clear and consistent. We feel that as the parties to the peninsula’s nuclear weapons problem, the meeting between the leaders of North Korea and the United States will have a critical impact on the progress of the process towards the denuclearization of the peninsula.”

The Senate Should Oppose the New Low-Yield Trident Warhead

This week, the Senate Armed Services Committee will take its turn to mark up the FY 2019 National Defense Authorization Act (NDAA). This also gives it an opportunity to weigh in on the Trump administration’s proposal for a new, lower-yield warhead for the Trident D5 submarine-launched ballistic missile (SLBM), funding for which is included in the bill.

The new warhead, designated the W76-2, will reportedly have a yield of 6.5 kilotons and would replace some of the W76 warheads currently on the Trident missiles, which have a yield of 100 kilotons.

The NDAA as it is now written would authorize $88 million in spending for the new warhead: $65 million from the Department of Energy’s National Nuclear Security Administration’s budget and $23 million in Department of Defense funds. The House Armed Services Committee earlier this month voted along party lines to reject an amendment that would have eliminated funding for the program from its version of the bill.

Despite the administration’s rhetoric about the need to strengthen deterrence, there is no good reason to develop a new warhead. As the head of the US Strategic Command, General Hyten, said himself in Congressional testimony earlier this year, “I have everything I need today to deter Russia from doing anything against the United States of America.” Worse, as many experts have pointed out, the new warhead could cause confusion for Russia and potentially increase the chances of miscalculation leading to an escalating nuclear exchange. Former Secretary of Defense William Perry has called such low-yield weapons “a gateway to a nuclear catastrophe.”

Opposition to this new program may be stronger in the Senate than in the House. It is certainly ripe for debate, given the dangers it presents and the questionable rationale the administration has put forward for it. To help make the case, more than twenty NGOs sent a letter to Senate Majority Leader Mitch McConnell that lays out the arguments against a new lower-yield Trident warhead.

It is unlikely that the Senate, in its current configuration, will stop the program, but it is important at the very least to ask the relevant questions about why we need such a weapon (we don’t) and how it would really affect US security (by decreasing it).

Closing North Korea’s Nuclear Test Site

Of the surprising announcements North Korea has made in recent weeks, one of the most surprising was its statement that it would not only end nuclear tests but shut down its nuclear test site with international observers watching.

What should we make of this?

Pyongyang said it would allow journalists from the United States, Russia, Britain, and South Korea to watch the destruction of the tunnels at Punggye-ri sometime in the coming week (May 23-25). These tunnels dug into the mountain are where North Korea conducts its nuclear tests. US intelligence says that North Korea is already dismantling the test site, and satellite photos of the site (here and here) confirm that a number of facilities at the site have already been torn down.

Punggye-ri Test Site (Source: Google Earth)

If North Korean leader Kim Jong-un is serious about limiting and perhaps eventually eliminating his nuclear and missile capabilities in return for economic engagement with the outside world, the question is how he demonstrates that seriousness. Publicly shutting down his test site is a meaningful step in the right direction and an interesting way to try to send that message.

It’s true that shutting down the Punggye-ri test site does not prevent North Korea from ever testing again. If negotiations fail or situations change in the future, it could decide to tunnel at a different site and build the required infrastructure needed to test. But it’s a meaningful and pretty dramatic action nonetheless.

For one thing, while part of the current test site is no longer usable because some tunnels collapsed after previous tests, experts agree that a couple tunnels at the site remain usable. They also agree that disabling the facilities would take time to reverse—perhaps months or longer.

This reminds me of North Korea’s decision in 2008 to disable its nuclear reactor at Yongbyon by  blowing up the cooling tower and letting foreign reporters film the event. This was at a time when negotiations with the United States seemed to be moving ahead. A few years later after negotiations had stalled, Pyongyang built a new cooling system and was able to restart the reactor. But disabling the reactor was still a meaningful action, since it kept the reactor from operating for several years.

What’s next?

North Korea’s statements last week raised the possibility that Kim was walking back his various offers. Yet Kim’s criticism was focused on statements by John Bolton and others about the need for the North to denuclearize as an early step of negotiations. This is an approach Pyongyang has consistently rejected, calling instead for a step-by-step process that helps build the trust needed for additional steps.

President Trump’s subsequent statement disavowing this so-called “Libyan model” of disarmament seemed intended to help repair the situation, but his later statement that appeared to threaten destruction of North Korea if talks failed could have exactly the opposite effect and lead Kim to cancel or delay the talks. In the meantime, China has urged Pyongyang to continue with the talks.

So whether or not the summit will proceed as planned remains uncertain. An important indicator will be whether North Korea goes ahead with destroying tunnels at its test site this week.

A Response to Roberts and Payne

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.

High Energy Arc Faults and the Nuclear Plant Fire Protection IOU

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.

Fig. 1 (Source: Nuclear Regulatory Commission)

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.

Fig. 2 (Source: Nuclear Regulatory Commission)

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.

Fig. 5 (Source: Nuclear Regulatory Commission)

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.

Made in Chattanooga

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.

Fig. 4 (Source: Oak Ridge National Laboratory)

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.

NRC Cherry-Picking in the Post-Fukushima Era: A Case Study

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.

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