As this photograph shows, the spent fuel pools at Units 3 and 4 at the crippled Fukushima Dai-ichi nuclear complex are exposed to the open sky and might be draining. The radioactive dose rates coming off the pools appear to be life-threatening. Lead-shielded helicopters trying to dump water over the pools/reactors could not get close enough to make much difference because of the dangerous levels of radiation.
If the spent fuel is exposed, the zirconium cladding encasing the spent fuel can catch fire — releasing potentially catastrophic amounts of radiation, particularly cesium-137. Here's an article I wrote in January 2002 in the Bulletin of Atomic Scientists about spent fuel pool dangers.
In October 2002, Washington Gov. Christine Gregoire — serving at that time as her state's attorney general—organized a group letter to Congress signed by her and 26 of her counterparts across the nation. In it, they requested greater safeguards for reactor spent-fuel pools. The letter urged "enhanced protections for one of the most vulnerable components of a nuclear power plant — its spent fuel pools." It was met with silence.
In January 2003, my colleagues and I warned that a drained spent fuel pool in the U.S. could lead to a catastrophic fire that would result in long-term land contamination substantially worse than what the Chernobyl accident unleashed. An area around the Chernobyl site roughly half the size of New Jersey continues to be considered uninhabitable.
The Nuclear Regulatory Commission (NRC) and the nuclear energy industry strongly disagreed. Congress then asked the National Academy of Sciences (NAS) to referee this dispute.
In 2004, after the NRC tried unsuccessfully to suppress its report, the NAS panel agreed with our findings. The Academy panel stated that a “partially or completely drained pool could lead to a propagating zirconium cladding fire and release large quantities of radioactive materials to the environment."
U.S. reactors are each holding at least four times as much spent fuel as the individual pools at the wrecked Daiichi nuclear complex in Fukushima. According to the Energy Department, about 63,000 metric tons of spent fuel has been generated as of this year, containing approximately 12.4 billion curies. These pools contain some of the largest concentrations of radioactivity on the planet. Merely 14 percent of U.S. spent fuel is in dry storage.
At this stage it's critical that:
- The NRC hold off on renewing operating licenses for nuclear reactors, given our newfound certainty that many sites in earthquake zones could experience greater destruction than previously assumed.
- The NRC promptly require reactor owners to end the dense compaction of spent fuel, and ensure that at least 75 percent of the spent fuel in pools operating above their capacity be removed and placed into dry, hardened storage containers on site, which are more likely to withstand earthquakes.
In our 2003 study, we estimated that it would take about 10 years to do this with existing technology, at an expense of $3.5 to $7 billion.