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Nuclear Safety Deferred: U.S. Reactors One Year after Fukushima

Jordan Weaver

Posted March 5, 2012

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Read the nuclear program's take on the NRC-Fukushima response here.


Full Report (PDF)

In the days that followed the 2011 Great Tōhoku Earthquake and Tsunami, news outlets around the globe followed the unfolding catastrophe at the Fukushima Dai-ichi nuclear power plant with what seemed like minute-by-minute coverage. The world witnessed the Japanese rescue workers struggling to keep the plant’s nuclear cores from overheating and melting. We saw graphic images of hydrogen explosions destroy multiple reactor buildings, televised in real-time. Reports came in of large evacuations that seemed to become more urgent and wide-reaching with each passing day. And it didn’t take too long before other countries and their citizens began to question the safety of their own nuclear reactors. Being a nuclear engineering graduate student at the time, I received my fair share of phone calls from family members and friends, all of them wanting to know: What is really going on and could this happen here?

Closing in on the one-year anniversary of the largest nuclear accident since the 1986 Chernobyl disaster, those of us in the United States are still left wondering: Has anything changed? What have we learned from the Japanese accident, and is the U.S. nuclear industry safer than it was a year ago? Should Americans be confident in our nuclear regulators?

In the months that followed the Fukushima disaster, the Nuclear Regulatory Commission (NRC) and the nuclear industry assured us that the accidents in Japan and the ever-compounding complications seen there were extremely unlikely to occur in the United States. Nonetheless, the NRC tasked a team of its own experts to conduct a study and to report back with an assessment of the “domestic nuclear fleet,” highlighting any changes in reactor safety-related systems, emergency equipment, and procedures that would be prudent to implement in light of the events and lessons learned at Fukushima. On July 12, 2011, the agency’s Near-Term Task Force released its findings and the Chairman of the NRC was hopeful that a decision could be made on implementing the report’s recommendations within 90 days. As news came that there might be an effort to stall this safety overhaul, NRDC’s Nuclear Program submitted more than a dozen rulemaking and order petitions related to the report’s recommendations to spur the Commission into action. A little more than a month later, NRC began conducting public meetings to solicit comment from industry and external stakeholders, NRDC among them, on the conclusions reached in the report and what the next steps should be for the Commission.

The Task Force provided over 30 action items to the NRC, including proposals for eleven Commission orders, seven rulemakings, and more than a dozen other key suggestions such as improving our understanding of hydrogen explosions and protecting against earthquake-induced fires and floods. It seemed like a good start. Not surprisingly, the industry groaned, the agency listened, and we ended up with a “prioritization” of the report’s recommendations. They divided up the Task Force’s list into three tiers. The first, Tier 1, was a subset that should be undertaken “without unnecessary delay,” implicitly leaving the rest, Tiers 2 and 3, to be dealt with on a more relaxed timetable, or not at all. As we will see soon, even those recommendations in Tier 1, despite the issuance of draft orders and letters in time for the Fukushima anniversary, are going to experience a rather drawn out implementation. If we are to assume these changes are needed to make our nuclear plants safer, then the plants that agree they are required to conduct these changes will not be safer for years to come.

But here we are, one year following the accident and the NRC states openly that as of December 6, 2011 they had not required any plant modifications or changed any regulatory requirements as a result of the Fukushima disaster. They also acknowledged that they are not aware of any significant plant modifications made by the industry. But here’s what we did get: a bunch of meetings that resulted in the NRC finally asking for information (which in many cases they already have) to inform the Staff’s proposed regulatory actions to improve safety (which the Commission may or may not actually vote to make mandatory). And let’s not forget the soap opera Congressional hearings in December that publicly aired the dysfunctional personal dynamics on the Commission, which could be mostly viewed as a distraction but some experienced observers viewed as payback from the industry and its supporters on the Commission for the Chairman’s aggressive initiatives to make nuclear safety first in the wake of the Fukushima accident.

Setting aside the demotion of numerous Task Force recommendations to uncertain Tier 2 and 3 status, we can look at the Tier 1 items up for vote before the Commission in time for the Fukushima Anniversary.  Among all the recommendations proffered by the Task Force, only seven of these items are in the Tier 1 actions, and even some of these are watered down versions of the originals. There are three orders requiring actions on:

  1. mitigation strategies for beyond-basis-external events, such as severe flooding and earthquakes, that could lead to a total loss of electricity to power critical reactor safety systems;
  2. installation of reliable hardened containment vents, to release the dangerous buildup of pressure and hydrogen that occurs when the reactor core overheats in an accident; and
  3. upgrades to spent fuel pool instrumentation, so that reactor operators are able to monitor the status of these pools under severe accident conditions.

It is important to note that the NRC staff made a key suggestion to issue these orders under the assumption that these actions redefine the level of adequate protection to the public health and safety. In other words, all plants are required to do this. No exceptions. Without this requirement, a plant owner could seek an exemption from the order based mostly on cost-benefit considerations, via the “backfit rule.” The NRC has recently published the Commission voting record for these upcoming actions. While it seems the backfit loophole will not be an option, a majority of the Commissioners did not like the suggestion that all of these orders “redefine” the level of adequate protection. They offered two alternatives. They suggest either administrative exemptions to their own regulations with regard to the backfit rule or changing the wording so that these orders are viewed as “ensuring continued adequate protection.”

Mitigation for Beyond-Design-Basis External Events

NRC recommended mitigation strategies designed to ensure that each nuclear power plant is adequately prepared, in terms of equipment, procedures, and training, to handle events that are greater than what they were designed to withstand (called “beyond-design-basis external events”) at all reactor units on site. This includes events like exceedingly large earthquakes and tornadoes, or flooding that exceeds historic levels. The intention was to provide some intermediate measures for handling severe accidents and “station blackouts” (SBOs) until the completion of an SBO rulemaking, which is part of the Tier 1 actions, but isn’t expected to happen for another 2 – 3 years. The occurrence of station blackout – a complete loss of both offsite and onsite backup power to a nuclear power station – was one of the most detrimental aspects of the Fukushima disaster, from which most other problems originated.

Another hot topic has been the vulnerability of US reactors to seismic and flooding hazards. The NRC is planning to perform hazard re-evaluations and plant “walkdowns” to identify any weak points in a plant’s systems and structures. Yet, the NRC hardly seems eager for answers to these questions because they will remain largely unaddressed for years due to the industry’s cries of “limited resources” to handle the agency’s requests for information. The initial idea was to receive an industry response from each site by 2015, followed by some sort of regulatory action if needed. Now, the NRC is estimating that it could take up to 7 years to receive responses from all plants. Unfortunately, a plant’s seismic and flooding vulnerabilities are not sympathetic to supposed “resource problems” in the industry and NRC bureaucracy  and, therefore, will not take a rain check for the next 10 years while we figure it out.

Venting to Lower Risk of Containment Failure

Of all the Tier 1 actions, the one that seemed the most likely to actually result in plant modifications (albeit after 3 years) was the installation of reliable hardened vents for BWR Mark 1 and 2 containments. This recommendation is meant to address the problems seen at Fukushima following the station blackout in which the containment pressures grossly exceeded their design limits. The workers had difficulties in operating the vents and could not successfully relieve the pressure. Because it is not a currently-required design feature, the Task Force felt this was an appropriate recommendation back in July of last year, but the response from industry was “we do not have enough information to immediately impose this.” Oddly enough, the NRC has recognized this vulnerability since at least 1990, but never formally required the industry to rectify it. And after nearly eight months of discussion, the order that is expected to come from the NRC by March 11, 2012 will likely look exactly as it did at the beginning of this process, and they will have wasted that time arguing the merits of venting when they could have been discussing how to expedite the implementation of this key severe accident mitigation upgrade, or (heaven forbid) actually strengthened  it by also requiring vent filtration systems.

Despite initial estimates of completion by March 2015, the NRC’s revised plan is now to have all actions related to this venting order, as well as the other two orders, completed by no later than the start of 2017. The NRC blames this delay on, among other things, an unresolved “policy issue” of whether containment vents with or without filters should be required to operate under severe conditions. If this sounds counterintuitive, that’s because it should be obvious that a severe accident mitigation technique be capable of operating under severe accident scenarios. But this is “NRC world,” where “safety deferred” does not equate, at least in the minds of regulators and licensees, to “safety denied.”

Spent Fuel Safety

With regard to spent fuel pool safety issues, reports have shown that even though the pools at the Fukushima plant survived relatively unscathed, there was ample confusion over the actual state of the pools, one of which contained freshly offloaded fuel and was at risk of overheating. Critical manpower and cooling water supplies were diverted to ensure that spent fuel pool cooling was maintained, while in hindsight other critical systems suffered. The Task Force felt this was a valuable lesson and recommended that reactor sites should install reliable safety-related instrumentation to monitor key pool parameters such as water level, temperature, and area radiation levels from the control room. Not surprisingly, the industry felt this was asking too much. Instead of “safety-related,” which ensures certain safety-engineering requirements are met, they would rather it just be “reliable.” And instead of having layers of potentially useful information (water level, temperature, radiation levels), they reasoned that knowing only the water level should be sufficient. The NRC staff listened and the order language looks uncomfortably similar to these suggestions. It is not clear if the plans they’ve formulated will prevent them from having to throw an unnecessary “Hail Mary” pass during a severe accident scenario in order to protect the spent fuel from overheating.

Since the accident in Japan, numerous other countries have enacted moratoriums on nuclear power production, slowed progress on construction, or decided to phase out nuclear energy entirely. Amidst all of the complaints of limited resources and urgings to proceed “carefully” (usually meaning slowly), how else have the NRC and the nuclear power industry been using their resources over the past year?

Since the accident in March 2011, the Commission has approved nine license renewals (versus three in the 12 months prior) and accepted an additional 4 applications. Additionally, the NRC approved five power uprates (versus six in 2010) and the industry submitted nine applications for uprates compared to the five in 2010. This is surely an obtuse, ostrich-like response to the undeniable fact that the one of the most technologically developed countries in the world experienced a catastrophic failure of its safety systems, resulting in multiple meltdowns and widespread contamination of the surrounding environment. In addition to lacking caution and sensitivity to heightened public concern over nuclear safety, the actions of the U.S. nuclear industry reflect an effort to sidestep any responsibilities to improve safety, and instead continue business as usual, or apparently, even faster than usual.

The consequences of this disaster are still being tallied but it is clear that there will be long-felt repercussions for the Japanese economy, the physical and emotional health of the affected population, the future environmental quality of the contaminated areas, and more widely the global energy industry. Japan faces large projected financial and technical burdens related to the nuclear accident, with various estimates regarding the overall cost and time required for recovery, all dauntingly large. The task is not simple, with many unknowns that are still being debated. However, the world is beginning to understand the true magnitude of a modern-day nuclear accident.

Unfortunately, there is no discussion in any of the NRC recommendations of what would be considered intolerable or unacceptable consequences if the worst case accident were to occur at a US nuclear plant. What the Commission must now consider is the sum total of economic damage and social disruption that might be inflicted by a Fukushima-scale accident occurring in a much more densely populated area, and what additional safety measures, if any, could reliably mitigate these potentially disastrous consequences. This is a critical near-term question, for example, for communities in the New York City, Philadelphia, and Los Angeles areas (the Indian Point, Limerick, and SONGS reactors, respectively, face license extenstion proceedings).

The Task Force Report did not touch upon or consider recommendations relating to this fundamental issue, and this represents a yawning gap in the Commission’s response to date to the Fukushima disaster. The NRDC Nuclear Program has addressed this issue in detail in the case of Indian Point and, to mark the first anniversary of the Fukushima accident, we are putting up a web feature that shows severe accident radiation contours for all U.S. nuclear power plants, assuming each of these had suffered a similar accident on March 11, 2011. 

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Comments (Add yours)

Hidden problems ?Mar 5 2012 02:16 PM

The amount of nuclear fuel in the collapsing MOX core of reactor 3 is vast compared to the mass required for a critical configuration. In view of the simultaneous loss of control rod geometry, an accidental (prompt ?) criticality in a somewhat undermoderated system inside the RPV of this reactor on March 14, appears not far sought.

After explosion information as to the state of this reactor remains remarkably sparse. Is the RPV intact ? Has the RPV head, containment dome been located ?

May there be unpublished facts further to hydrogen explosions and melt downs that make post Fukushima LWR ruling even tougher ?

FrankTradesMar 8 2012 10:55 AM

The consequences of the Fukushina disaster can be laid on the doorstep of those responsible for the design basis for tsunami protection, nothing more. An 800-year return period protection wall there compares to the designs of US nuclear plants that take 100,000 and 1,000,000-year return period into account for floods, earthquakes, hurricanes, tornadoes, fires and other natural disasters.

Case closed, except for the reviews of US plants that will be done anyway!.

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