Nuclear storageNRC: storing spent nuclear fuel in cooling pools is safe

Most of the members of the Nuclear Regulatory Commission (NRC) last week said they considered it safe to continue storing most spent nuclear fuel in cooling pools, although there is a concern about potential accidents and terrorist attacks.

The New York Times reports that four of the five commission members indicated at a hearing that storage in the pools was safe enough relative to moving some of the spent fuel into giant steel and concrete casks, where it can be stored dry, with no reliance on water, pumps, or filters to keep them cool (not everybody agrees. See “Science group: storing spent nuclear fuel in dry casks significantly safer then wet pools storage,” HSNW, 30 July 2012).

Following the March 2011 Fukushima disaster, worries about the safety of soring spent fuel in cooling pools grew. Damage to a pool at the facility caused radiation risks in areas fifty miles from the plant. The Times notes that even before Fukushima, the National Academy of Sciences, in a study requested by Congress in the wake of 9/11, found that a successful terrorist attack on a spent fuel pool was plausible. The study called on regulators to consider reducing the loading in spent fuel pools, which hold far more radioactive materials than nuclear reactors do.

“It’s legitimate to describe spent fuel pools at reactors in the United States as pre-emplaced radiological weapons,” Gordon Thompson, the executive director of the Institute for Resource and Security Studies in Cambridge, Massachusetts, and a research professor at Clark University in Worcester, Massachusetts, told the commissioners. The spent fuel pools are a magnet for terrorists, he said.

David Heacock, the chief nuclear officer of Dominion Nuclear, which operates several reactors in, said that the probability of an event that would damage a spent fuel pool was “effectively zero” and that the steps needed to mitigate such an accident were simple, with preparations already made.

“This is not a complicated mitigation, nor is it difficult,” he said. “It’s basically, just add water.”

Nuclear fuel is only  minimally radioactive when it is placed in a reactor, but when uranium is split, the fragments, materials like strontium and cesium, are unstable and seek to return to stability by giving off energy, or subatomic particles, for as long as centuries. The particles continue to produce heat so they must be stored under water for a few years.

Scientists say that the nuclear reactors now in service in the United States were built with the assumption that the spent fuel would be removed from nuclear the facilities after a few years, but because the government has failed to provide a centralized place to store the spent fuel, utility companies have had to store an ever-growing quantity of it in spent fuel pools on the grounds of nuclear facilities.

Thompson told the commission that if water was drained from a spent fuel pool, the radiation field would be so intense that it would deliver a fatal dose to a worker within minutes, making “mitigating action” impossible. The nuclear industry disagrees.

The Times reports that NRC chairwoman Allison Macfarlane was the only commissioner of the five whose questions indicated she might be open to moving more fuel to dry casks, which are already in use. Before she was appointed to head the NRC, Macfarlane spoke favorably of that idea, as did her predecessor, Gregory Jaczko, before he was named chairman. Both Macfarlane and Jaczko, though, did not use their position as NRC heads to advance the idea.