Environment  
comments_image Comments

How the Government Is Pinching Pennies and Cutting Corners When it Comes to Nuclear Safety

It appears the lessons from Fukushima have not been learned.
 
 
Share

Photo Credit: AFP

 
 
 
 

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:

  1. "Power supply vehicles" capable of providing additional emergency power for seven days in the event of a loss of outside electric power,
  2. Filters on emergency vents capable of reducing the radiation emitted in the event of an accident and,
  3. 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.)

 
See more stories tagged with: