What Will the N.R.C. Learn From Fukushima?

The New York Times: Environment: What Will the N.R.C. Learn From Fukushima?
The trait that doomed the Fukushima reactors might not be so obvious, the chairman of the Nuclear Regulatory Commission told a mostly skeptical audience at a forum organized by an anti-nuclear group on Monday.

Since an earthquake and tsunami set off the disaster in Japan on March 11, many people have focused on inadequate earthquake preparedness and the design of the reactors’ containment structures as likely factors that undid the plant.

But the chairman of the regulatory commission, Gregory B. Jaczko, said at a lunch-hour meeting arranged by Public Citizen that “right now, I would say we’re not primarily focused on seismic events.” Vulnerability to flooding might be the more appropriate lesson, he said, but it will take time to figure out even that.

He said that Japan’s situation would be “an interesting challenge for us for many years.” The commission’s response will be “systematic and methodical’’ rather than immediate because the first task is to figure out what equipment or procedures in American reactors should be changed, he added.

Responding to a question about what should be done about 23 reactors in the United States that have the same containment design as the Fukushima models, built by General Electric, Mr. Jaczko said that the type of containment might not in fact be the biggest factor.

Both General Electric and American companies that operate G.E. reactors have tried intermittently to make the same point as Mr. Jaczko.

The Tennessee Valley Authority took reporters on a tour of its Browns Ferry reactors near Athens, Ala., soon after the Fukushima accident and guided them up three flights of stairs to reach the switchgear that controls the operation of pumps and valves around the plant. Although both Fukushima and Browns Ferry have G.E. Mark I containments, Fukushima’s switchgear was on the ground floor and was destroyed.

That’s one reason why the reactors’ main cooling systems still could not be operated even after workers completed a new connection to the electric grid at the plant.

The Nuclear Regulatory Commission examines plants for both the prospect of internal flooding – produced by a pipe break or a leak – and external flooding, Mr. Jaczko said. Last year the commission issued a report on the Fort Calhoun reactor on the Missouri River in Omaha that said it was not adequately prepared for an external flood. A follow-up inspection is scheduled for later this year.

The Fukushima accident is likely to “affect all of the plants, regardless of their age or their pedigree,’’ and that includes plants that have not yet been built, he said.

Others have said that a likely follow-up to Fukushima would be to move some spent fuel out of the fuel pools at American reactors, which are loaded far more heavily than the pools at Fukushima were.

An obvious alternative is loading fuel into steel capsules and then filling the capsules with inert gas, sealing them and lowering them into small concrete silos, the so-called arrangement called dry cask solution. The casks have no moving parts; air circulating around the outside of the capsule carries off the heat.

But Mr. Jaczko would not go so far as to commit himself to that approach. “No matter how you store spent fuel, each approach to dealing with it is going to have different strengths and weaknesses,’’ he said.

The commission staff is about 20 days into a 90-day study, but that is not the end point; the staff will soon commence a six-month study in greater depth, he said.

In testimony on Capitol Hill and other public statements, Mr. Jaczko has avoided criticizing his Japanese counterparts. But on Monday he said that “if we had a similar type of event in the U.S., we certainly would like to be providing a lot more information to the public.’’