1 Nuclear Near Misses: A Decade of Accident Precursors at U.S. Nuclear Plants 2 Photo Source: U.S. Nuclear Regulatory Commission, Fukushima and Subsequent Lessons Learned Actions, NRC Commissioner William C. Ostendorff, Pennsylvania Society of Professional Engineers September 19, 2014 http://www.nrc.gov/about-nrc/organization/commission/ comm-william-ostendorff/comm-ostendorff-20140919-slides.pdf Greenpeace US would like to dedicate this report to those individuals at the U.S. Nuclear Regulatory Commission (NRC) who have attempted to regulate reactors and reduce the risks they pose to public health and safety. These individuals have risked their careers by speaking truth to power inside the NRC and informing the public of the risks posed by nuclear power plants. Copyright 2016 by Jim Riccio and Greenpeace Inc. TABLE of CONTENTS: 3 Executive Summary Introduction Nuclear Near Misses Terminology & Methodology Nuclear Power Plant Risk After Fukushima A Decade of Nuclear Near Misses at US Nuclear Plants Important Near Misses at US Nuclear Plants Near Misses at US Nuclear Plants: Flooding Near Misses at US Nuclear Plants: Loss of Offsite Power The U.S. Nuclear Regulatory Commission’s Missing Near Misses Did the NRC Mislead Congress? Conclusion Endnotes Appendix A: Nuclear Near Miss Events 2004 - 2014 Appendix B: Nuclear Near Miss Conditions 2004 - 2014 Appendix C: Nuclear Near Misses Not Modeled in Risk Assessments Appendix D: Oconee Time Line 3 Nuclear Near Misses: A Decade of Accident Precursors at U.S. NuclearPlants Greenpeace 4 Executive Summary Thirty years after Chernobyl and five years after the triple meltdown at Fukushima Daiichi in Japan, U.S. nuclear regulators are claiming that U.S. nuclear power plants are safe and that Fukushima couldn’t happen here. Nothing could be further from the truth. Contrary to these claims, Greenpeace has documented 166 near misses or acci- dent precursors at US nuclear power plants over the past decade that risk analysts have determined are precursors to a meltdown. The U.S. Nuclear Regulatory Com- mission (NRC) documented 61 events and 102 conditions at US nuclear plants that were near misses to a meltdown. Unfortunately, NRC’s Accident Sequence Precursor program missed three of the most risk significant near misses in the past decade; the triple meltdown threat to Duke Energy’s Oconee Nuclear Station in South Carolina. According to NRC’s risk analysts, if Jocassee Dam failed all three of the nuclear reactors at Oconee were certain to meltdown. And contrary to the claims of the Nuclear Regulatory Commis- sion, the threat to the Oconee reactors was hundreds of times more probable than the tsunami that struck Japan in 2011. The NRC considers ten of these near misses to be important precursors to a core melt accident. 5 IMPORTANT NEAR MISSES AT U.S. REACTORS 2004 - 2014 66 The three reactors at Duke Energy’s only served to significantly delay the final Oconee nuclear plant weren’t the only resolution of nuclear near misses that are ones that were at risk from flooding. even more risk significant than those that The NRC has documented over a dozen caused the fiasco at Fukushima Daiichi other nuclear reactors that were threat- in Japan. The NRC’s failure to address ened by flooding over the past decade. long standing safety issues at Oconee Many of these near miss vulnerabilities and other U.S. nuclear plants further dated back decades and were only iden- serves to undermine public confidence in tified after the NRC was forced to take nuclear power and those that regulate it. a closer look at U.S. nuclear plants in the aftermath of Fukushima. In addition Greenpeace US’ report on Nuclear Near to the flooding vulnerabilities, NRC risk Misses finds that despite years of in- analysts identified a statistically signifi- spections, licensing and relicensing, cant trend in Losses of Offsite Power or safety issues continue to be identified at (LOOPs) at US nuclear plants. This trend U.S. reactors; many of which date back is a result of 20 LOOP events in just the decades, some vulnerabilities have ex- last four years. isted since the nuclear plants were first started. These long standing vulnerabil- Equally as disturbing as the 166 accident ities make nuclear power anything but precursors or near misses is the fact that safe. Greenpeace has long called for the NRC staff has had to turn whistleblow- phase out of nuclear power and this re- er on four of the top ten near misses in port further supports that determination. order to get the agency to address the risks in a timely manner. Contrary to the claims of U.S. regulators and the nuclear industry, nuclear pow- er plants can experience catastrophic failures like those we witnessed at Fuk- ushima Daiichi in Japan. This probabil- ity makes nuclear power anything but “safe”. The NRC’s failure to make public the documents that revealed the flood- ing threat to all three reactors at Duke Energy’s Oconee Nuclear Station has 7 Image: Sign in Restaurant in FukushimaSign saying that the milk is not from local cows - due to the high radiation in the area - at a restaurant in Fukushima City. Nuclear Near Misses: A Decade of Accident Precursors at U.S. NuclearPlants Greenpeace 8 Introduction Ten years ago, Greenpeace published Commissioners since the Fukushima our report American Chernobyl: Nuclear fiasco, that “(t)he NRC continues to de- Near Misses at U.S. Reactors Since 1986 termine that US nuclear plants are safe,”3 to remind the public and government Greenpeace’s review of a decade of officials that contrary to the claims made nuclear near misses shows that US reac- by the nuclear industry lobbyists and tors are still vulnerable to both flooding U.S. Nuclear Regulatory Commission and losses of off-site power as well as (NRC) Chairman and Commissioners: other vulnerabilities to a meltdown that make them anything but “safe.” *U.S. reactors can have acci- dents with consequences equal to or NRC risk analysts have documented greater than the Chernobyl disaster; 163 events or conditions at U.S. nucle- ar power plants in the last decade that *U.S. reactors have had and will could have resulted in a meltdown. In continue to experience “near misses” addition to these 163 accident precur- that could result in a meltdown; sors or near misses identified by the NRC, Greenpeace has documented *U.S. reactor containments were three important near misses that NRC not designed to withstand a reactor risk analysts failed to review under the meltdown and the government has lit- NRC’s Accident Sequence Precursor tle confidence that any of them could. Program (ASP). Now, thirty years after Chernobyl and After Fukushima the nuclear industry and five years after the meltdown of three its regulators have been forced to reex- General Electric-designed nuclear reac- amine the holes in the nation’s nuclear tors1 at the Fukushima Daiichi nuclear safety net4. But as former NRC Chair- plant in Japan, U.S. NRC Commission- man Gregory Jaczko noted “unfortunate- ers are again claiming that U.S. reactors ly, all too often, when faced with tough are “safe” and that “Fukushima couldn't policy calls, a majority of this current happen here.”2 commission has taken an approach that is not as protective of public health and Despite blithe assurances from the NRC safety as I believe is necessary.”5 Nuclear Near Misses: A Decade of Accident Precursors at U.S. NuclearPlants Greenpeace Nuclear Near Misses 9 In order to compile the last decade of To analyze initiating events, the NRC cal- nuclear near misses Greenpeace re- culates a conditional core damage prob- viewed the U.S. Nuclear Regulatory ability or CCDP. CCDP represents the Commission’s (NRC) program for track- probability that the nuclear reactor would ing and evaluating near misses or as experience core damage or a meltdown the agency terms them “precursors to of the radioactive fuel rods, given an oc- severe core damage accidents” or “ac- currence of the initiating event and any cident precursors.” Accident precursors subsequent equipment failure or degra- are those actual events or conditions at dation.10 nuclear reactors that if additional failures had occurred, would have resulted in in- To analyze degraded conditions, the adequate cooling of the radioactive fuel NRC calculates the increase in core and caused it to meltdown.6 The NRC damage probability or CDP. CDP repre- analyses inspection reports and licensee sents the increase in the probability that event reports submitted by the nuclear the reactor would damage the core for plant operators to capture those events the period that safety equipment was un- or conditions that could have led to a available or incapable or performing its meltdown. function. 11 For the purpose of analyzing risk, the Once the NRC has assessed an event, NRC divides nuclear reactor risks into they determine the probability that it two categories: initiating events and could have led to a meltdown. The degraded conditions.7 Initiating events NRC’s Accident Sequence Precursor are actual occurrences such as a loss (ASP) program uses CCDP and CDP of offsite power (LOOP) or an automat- interchangeably and uses scientific no- ic or manual shutdown (SCRAM) of the tation to describe the significance. For reactor with complications like any addi- example Three Mile Island, Chernobyl tional equipment failures or degradation and Fukushima the core damage proba- of safety system function.8 Degraded bility was 1 in 1. conditions are those recognized safety system or equipment degradations or unavailability that came to light without an occurrence of an initiating event.9 Nuclear Near Misses: A Decade of Accident Precursors at U.S.