The opinion reportedly voiced by NRC Chairman Greg Jaczko yesterday about spent fuel safety is not only a flip-flop from his position as of a few years ago, but indicates why the oversight process for nuclear power in the US badly needs to be overhauled.
A March 31 press story (subscription) reports:
The top U.S. nuclear regulator said today there’s no meaningful difference in safety between submerging spent nuclear fuel in water and encasing it in concrete casks.
“We don’t have technical information that says it is safer to be in one or the other,” Nuclear Regulatory Commission Chairman Gregory Jaczko told a House Appropriations subcommittee. “The likelihood of anything happening is so small, it’s hard to say that one is safer than the other. It’s like [the odds of] winning the Powerball versus winning another lottery.”
There are several problems with this statement.
First, just because two problems are both unlikely to occur does not mean their probability is the same. You still have to look at the relative probability of the two occurrences.
Second, it’s not just a question of how likely it is that a crisis will occur, but how big the potential impact of that crisis would be.
Third, there IS technical information on this issue.
Analysis that we and others (including the National Academy of Science—see below) have done shows that moving older spent fuel from pools to dry casks reduces both the likelihood and potential impact of an incident affecting spent fuel.
Moreover, in 2008 Chairman Jaczko agreed with that assessment, stating:
The most clear-cut example of an area where additional safety margins can be gained involves additional efforts to move spent nuclear fuel from pools to dry cask storage.
If there’s new information that has changed Chairman Jaczko’s mind since 2008, he should say what it is. The most recent evidence we’ve seen—the current crisis in Japan—has instead strengthened our sense that no matter how unlikely you might believe nuclear crises to be, they can and do still happen, and the NRC must take what steps it can to protect the public from such a crisis.
There will always be unforeseeable events that are hard to plan for and prevent. But there’s no excuse for not acting on those that are foreseeable and for not taking steps that have already been identified—by the Chairman himself—to make nuclear power safer.
Excerpts from US National Academy of Sciences report “Safety and Security of Commercial Spent Nuclear Fuel Storage” (2006), pp. 68-70:
Less spent fuel is at risk in an accident or attack on a dry storage cask than on a spent fuel pool. An accident or attack on a dry cask storage facility would likely affect at most a few casks and put a few tens of metric tons of spent fuel at risk. An accident or attack on a spent fuel pool puts the entire inventory of the pool, potentially hundreds of metric tons of spent fuel, at risk.
The potential consequences of an accident or terrorist attack on a dry cask storage facility are lower than those for a spent fuel pool.
The recovery from an attack on a dry cask would be much easier than the recovery from an attack on a spent fuel pool.
Dry cask storage for older, cooler spent fuel has two inherent advantages over pool storage: (1) It is a passive system that relies on natural air circulation for cooling; and (2) it divides the inventory of that spent fuel among a large number of discrete, robust containers. These factors make it more difficult to attack a large amount of spent fuel at one time and also reduce the consequences of such attacks.