Operators of Diablo Canyon and other U.S. nuclear power plants are not required to prepare for the kind of disaster that recently overwhelmed a nuclear facility in Japan, federal regulators revealed Thursday.
At a hearing in Washington, D.C., a U.S. Nuclear Regulatory Commission task force said it is considering whether new rules are needed to force power plant operators to prepare for multiple simultaneous nuclear reactor failures.
When an earthquake and tsunami struck Japan on March 11, the three reactors that were working at the Fukushima Daiichi nuclear power plant failed, leading to a series of explosions and substantial radioactive releases into the air and ocean.
Diablo Canyon, which operates in San Luis Obispo County within hundreds of feet of a recently discovered and little-studied seismic fault, contains two nuclear reactors.
Current nuclear regulations require power plant operators to be prepared for the failure of one nuclear reactor following an earthquake, flood or other disaster, but the emergency protocols can assume that another working reactor unit will be available to provide backup electricity and cooling water supplies to the stricken reactor.
Reliable supplies of electricity and water are critical for preventing a nuclear meltdown following a disaster such as an earthquake, because they are used to cool plutonium and other fuel. “You can cross-tie different emergency power sources between units,” NRC spokesman Scott Burnell said in an interview. “Each unit will have backup water tanks.”
“One of the insights that we did get as a result of Fukushima was that you have to take a step back and consider what would happen if you had multiple units affected,” task force leader Charles Miller said Thursday in response to a question from a commissioner during the group's first public hearing. “With regards to our insights, I think we’re trying to formulate where we go with that.”
PG&E, which owns Diablo Canyon, insists that the facility is safe.
"Should Diablo Canyon's two reactors face a loss of power from the grid and loss of emergency diesel generators like that faced by the operators at Fukushima Daiichi, our operators are trained to ensure that the plant will achieve and maintain safe shutdown during a station blackout scenario," PG&E Diablo Canyon spokseman Paul Flake said in an email Thursday. "They have operating procedures that guide them on actions to be taken in responding to this scenario."
PG&E and the NRC are moving forward with efforts to extend the power plant’s federal operating permits from 2025 to 2045, even though the company doesn't yet know whether an earthquake along the recently discovered Shoreline Fault would lead to a catastrophic meltdown.
The California Public Utilities Commission postponed an April hearing to consider PG&E's request to extend the plant's life by 20 years--through 2045, until it has learned lessons from Fukushima. The hearing has not been rescheduled.
The NRC's task force was formed in early April to suggest safety improvements for the US nuclear power industry in the wake of the Fukushima disaster.
The task force is comprised of six staff members of the NRC, which receives most of its $1 billion in annual funding from power plant operators through fees. A recent report in the New York Times raised questions about the NRC's ability to provide enough oversight, given its ties to the nuclear industry.
The report points out that since 2000, the agency has not denied any license renewal applications. "Absent dead bodies," former NRC official David Lochbaum told the paper, "nothing seems to deter the NRC from sustaining reactor operation.”
At Thursday's meeting, NRC task force members insisted that the nation’s 104 nuclear power plants are safe and characterized expected safety recommendations resulting from the Fukushima disaster as “enhancements.”
Although the hearing was open to the public, members of the public were not invited to comment and will be excluded from participating in the task force’s work.
“Unfortunately,” NRC Chairman Gregory Jaczko said during the hearing, “because of the time constraints with doing this quick review, we’ve not had the opportunity to have the kind of public participation we normally would have.”
The task force fielded relatively few tough questions at Thursday’s hearing, but another hearing scheduled Friday by a subcommittee of the House Committee on Science, Space and Technology could grow more contentious.
Friday’s oversight hearing will see lawmakers quiz experts, including those from the NRC and the Union of Concerned Scientists, about the safety of nuclear power in the US.
The task force will issue a report in July.