This article was published in partnership with GlobalPossibilities.org.
On March 11, 2011, a 9.0 earthquake and 45-foot-high tsunami overwhelmed the emergency cooling systems at the Fukushima Dai-ichi nuclear complex on Japan's eastern coast. Meltdowns occurred in units 1, 2 and 3. In addition, the unit 4 containment building was severely damaged, leaving 460 tons of spent fuel stored atop the building at risk of collapse. One-third of Fukushima Prefecture (eight percent of Japan's total land mass) and 1.5 million people were affected by fallout. The region's $3.2 billion agricultural sector was wiped out.
In the months following the multiple meltdowns, the Nuclear Regulatory Commission (NRC) formed a Near-Term Task Force (NTTF) to recommend protective countermeasures. The explosive demise of Fukushima's reactors had drawn special attention in the US owning to a singular, alarming fact: The reactors that failed in Japan were built by General Electric and 23 similar Mark I reactors were still operating at 16 sites in 12 US states. In addition, another eight Mark 2 reactors with similar design problems are located at five sites in four states.
On July 12, 2011, the NTTF issued a 96-page report containing 12 "overarching recommendations." Most were vague calls to "evaluate potential enhancements," "strengthen mitigation capabilities," and "identify insights." There was, however, one concrete recommendation. It called for "requiring reliable hardened vent designs [on all] Mark I and Mark II containments."
In internal memos, NRC staff warned that safety improvements were essential for "Mark I or Mark II containments to address specific design concerns (e.g., high conditional containment failure probability given a core melt)" that could result in "releases of radioactive materials, hydrogen, and steam into the reactor building." The addition of Hardened Containment Vents (HCVs) would allow reactor operators to release high-temperature and high-pressure gasses to the atmosphere, which could prevent reactor core damage that could generate dangerous accumulations of explosive hydrogen gas.
On the first anniversary of the Fukushima quake, the NRC issued a report that contained a surprising conclusion. The NRC ruled that a "sequence of events such as the Fukushima Dai-ichi accident is unlikely to occur in the US. Therefore, continued licensing activities [of US reactors] do not pose an imminent threat to public health and safety."
The NRC investigation clearly identified the failure of pressure vents on Japan's reactors as a major contributing cause of the meltdowns and explosions. Although the NRC acknowledged that the importance of HCV systems was "well established," the NRC noted that HCVs currently were "not required" on Fukushima-style rectors in the US. Moreover, at those US sites where HCVs had been voluntarily installed, "a wide variance exists with regard to reliability."
To address this critical safety lapse, the NRC has proposed that Mark I and Mark II reactors be equipped with "reliable hardened venting systems to ensure adequate protection of public health and safety." US operators were given until February 28, 2013 to submit plans on how they intend to implement safety upgrades.
In January 2013, Japan's Nuclear Regulatory Authority announced the imposition of three new safety measures for all of the country's existing reactors. These included:
- "Power supply vehicles" capable of providing additional emergency power for seven days in the event of a loss of outside electric power,
- Filters on emergency vents capable of reducing the radiation emitted in the event of an accident and,
- Creation of "secondary control rooms" built at a safe distance from operating reactors. In the event of an accident, these fallback control rooms would allow operators to safely attempt to cool reactor cores and, if needed, vent steam and radioactive gases into the atmosphere. (Germany and Switzerland already have such systems; the US does not.)
Japan's latest post-Fukushima guidelines also call for expanding evacuation zones surrounding damaged reactors from 5 to 30 kilometers (3-18 miles). (The NRC's mandatory evacuation zone inside the US is limited to 10 miles. During the Fukushima meltdowns, however, the State Department urged US citizens living in Japan to relocate at least 50 miles from the damaged reactors.)
To date, the NRC's Lessons Learned Task Force has only proposed adopting one of Japan's post-Fukushima safeguards -- the installation of HCVs with radiation filters -- but even this decision has come under fire. In January 2013, a phalanx of 21 pro-nuclear Republicans who serve on the House Energy and Commerce Committee signed a letter calling on the NRC to quash the radiation-filtering recommendation as too burdensome for the beleaguered nuclear industry. The industry fears the cost of installing external radiation filters could lead to the shutdown of many older US plants. (Three of the Congressional letter-signers come from states where a total of five Fukushima-style GE reactors were recently found to be at increased risk of damage due to earthquakes.)
While Japan has called for swift action to address these three critical protective measures, the NRC has indicated that the deadline for action on its single safety improvement, the installation of HCVs (currently set to be accomplished by December 31, 2016), may be pushed back to December 31, 2017.
In an Order to Modify Licenses alert sent to US reactor operators on March 12, 2012, the NRC expressed concern that the Fukushima disaster had shown how "extreme natural phenomena could challenge prevention, mitigation and emergency preparedness." In response, the NRC ordered the operators of 20 US reactors to "implement requirements for reliable hardened containment vents at their facilities." (The NRC actually ordered such improvements in 1989 but it turned out the vents needed electrical power and air pressure to operate and, in the event of an accident, electricity and air pressure could be lost. )
In its NUREG-1150 report on Severe Accident Risks, the NRC concluded that "the Mark I and Mark II containments do not have the same margins of safety that other containments have during accidents." This report went on to state: "The NRC and nuclear industry have recognized the potential need to vent Mark I and Mark II containment designs to cope with severe accident conditions since at least the early 1980s."
So why didn't the NRC act sooner? It was a cost-benefit decision. The Commission ruled that the expense of the making the upgrades was not warranted due to the "low probability" of a nuclear accident. In a report dated November 26, 2012, NRC staff noted that "legislators and regulators in other countries did impose requirements in the aftermath of the accidents at Three Mile Island and Chernobyl" clearly choosing "the defense-in-depth argument with less or no consideration of cost/benefit analyses." Still, the NRC was not swayed.
In their November 26, 2012 report, the NRC staff offered four options to the commissioners:
- Continue with planned addition of "reliable hardened vents,"
- Upgrade safety with "severe accident capable vents,"
- Design and install "engineered filtered containment venting" to block the release of radioactive clouds following an accident and,
- Consider additional strategies to handle "severe accident confinement."
The staff concluded both options 2 and 3 were "cost-justified in light of the substantial increase in the overall protection of the public health and safety" and recommended option 3. Neither of the two improvements will come cheap. The cost for installing Severe Accident Capable Venting Systems was estimated at $3,027,000 per reactor while the estimated unit cost to install Engineered Filtered Venting Systems totaled $16,127,000.
The Nuclear Energy Institute (NEI) and plant operators countered that expensive filters are "unnecessary" and that merely "hardening" the venting systems should suffice. The Electric Power Research Institute's (EPRI) argument against installing radiation filters was particularly wishful. "The best way to avoid radiological release and potential land contamination," EPRI argued, was to "prevent an accident from occurring." The NRC's Advisory Committee on Reactor Safeguards initially sided with industry's call for "performance-based standards" but NRC staff argued this approach would delay action by several years, thereby violating the commission's commitment to address the filtering issue "without delay."
Noting that filtering technologies already exist and "have been demonstrated through significant testing and application at nuclear power plants worldwide," the staff identified evaluation of filter vents as a "Tier 1 issue" -- i.e., an action "to be initiated without unnecessary delay."
The NRC's Tier 1 actions include: "evaluations" of flood and earthquake hazards; improved station blackout (SBO) regulations; strategies for addressing "beyond-design-basis events" (i.e., unplanned-for disasters); hardened vents for Mark I and Mark II containments; and installing instruments to monitor the stability of spent fuel storage pools.
The NRC's Tier 2 concerns (i.e. those requiring "further technical assessment and alignment") include: spent-fuel pool safety and evaluating the danger from hurricanes, floods and other extreme weather events.
The Tier 3 recommendations ("actions that require further staff study to support a regulatory action") include: "enhancements" to protect reactors from fires and floods triggered by earthquakes; requiring HCVs for other at-risk reactor designs; developing strategies to prevent or "mitigate" buildups of explosive hydrogen inside containment structures; improvements in handling a "prolonged station blackout and multiunit events," and providing staff training on how to deal with "severe accidents."
Citizens groups and nuclear watchdogs recently have urged the NRC to implement additional post-Fukushima safety measures but the commission seems determined to move slowly on a small number of focused changes.
On January 31, 2013, the Nuclear Information Resource Service (NIRS) and other organizations submitted a citizens' petition demanding that the NRC and the Federal Emergency Management Agency (FEMA) address a number of additional changes. These include:
- Expanding the 10-mile "emergency planning zone" to include a 25-mile "plume emergency zone," a 50-mile Emergency Response Zone, and a 100-mile "ingestion pathway zone."
- Update emergency response and evacuation plans to incorporate the increased dangers posed by climate change ‹ i.e., droughts, hurricanes, tornadoes, and flooding.
- Base emergency planning on real-life experiences (i.e., TMI, Chernobyl, Fukushima) and not simply on computer simulations.
- Acknowledge the National Academy of Science finding that "there is no safe dose of radiation" and increase protection levels for people threatened by long-term and sustained exposures. (Because women and children are most at risk, federal radiation guidelines should no longer be based on the anticipated risk to "the average man." The preferred guidelines should, instead, be based on the risks posed to a young girl.)
- Emergency supplies of potassium iodine tablets should be made widely available to protect populations against the risk of thyroid cancer, disease and mental retardation that can result from breathing and ingesting fallout byproducts.
- Establish "best practices" to determine whether "shelter-in-place" or "evacuation" poses the best response to a nuclear power plant accident.
It is now up to the NRC's five commissioners to decide whether to order operators to install safety improvements that could cost tens of millions of dollars-per-reactor. The Commissioners could insist or swift implementation or they could simply ask for "further study."
Unfortunately, as Beyond Nuclear notes, "the controversial and expensive 'fix' for the unreliable, aging and failing GE designs has clearly politicized the Commissioner's' upcoming vote."