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Nuclear Regulatory Commission coming west for San Onofre update

Allison MacFarlane is the newly-confirmed chair of the Nuclear Regulatory Commission.
Allison MacFarlane is the newly-confirmed chair of the Nuclear Regulatory Commission.

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The Nuclear Regulatory Commission is coming to Southern California next month for a public meeting about the next steps in de-commissioning the San Onofre nuclear power plant.

Regulating what happens to nuclear fuel at facilities such as San Onofre is part of the NRC's purview, says agency chairwoman Allison Macfarlane, whose appointment to the Nuclear Regulatory Commission was confirmed late last month.

Macfarlane is an expert on that side of the nuclear energy equation. She got her PhD in geology from MIT and has researched environmental policy and security issues related to nuclear energy. She also served on a presidential commission that looked at strategies for dealing with nuclear waste.

Step one, Macfarlane says, is moving spent fuel into a pool. She says it's "like a swimming pool, but 30-40 feet deep." About 200 fuel rods — 12-feet high, each about the diameter of a quarter — are bundled together and held in racks at the bottom of those pools. The water provides both cooling and protection from radioactivity.

Macfarlane says she's stood next to the pools at San Onofre "because my interest, of course, is in the back-end of the fuel cycle." 

MacFarlane says San Onofre's pools are designed to withstand earthquakes. She notes that even the pools at Japan's Fukushima nuclear plant remained intact after the magnitude 9 quake there. The tsunami, however, knocked the plant offline and operators weren't able to keep the water circulating in those pools.

At San Onofre, waste from the long-decommissioned Unit 1 has already been moved from pools to casks. "After the fuel has aged sufficiently so that it's no longer quite so thermally and radioactively hot" — after five years or so — "you can then put the fuel into these concrete and steel structures."

SoCal Edison has moved nuclear fuel out of Unit 3, the reactor with the problems that led to the shutdown at San Onofre. The utility plans to remove the fuel from Unit 2 later this summer.

The spent fuel will be stored on site, as it is at nuclear facilities throughout the U.S. The NRC will continue to monitor San Onofre. Macfarlane says it's the NRC's job "to protect public health and safety."

The NRC will brief the public about the de-commissioning process next month. The date and place are yet to be announced; the agency is having a difficult time finding a venue willing to host what will likely be a large — and noisy — public meeting.