The Nuclear Regulatory Commission's reviews of U.S. reactor safety are likely to include an examination of each plant's emergency preparations, its vulnerabilities to the loss of outside power and policies governing spent fuel pools, NRC Executive Director of Operations Bill Borchardt said yesterday.

"There is a wide range of topics. Almost nothing is off the plate," he told reporters following a hearing of the Senate Energy and Natural Resources Committee.

Borchardt reiterated the NRC's position that all 104 U.S. operating nuclear reactors are designed and equipped to operate safely if hit with predicted earthquake shocks. On-site storage of spent fuel in pools and dry cask containers also meets safety standards, he said.

Workers re-entered the abandoned control room of plant No. 2 at the Fukushima Daiichi nuclear power complex last weekend. Photo courtesy of Tokyo Electric Power Co.

But some of the existing assumptions about safety margins for plants facing sudden and extreme emergencies will be reviewed by the NRC post-Japan task force, he said.

The NRC has ordered a three-month inspection of nuclear plants to verify that additional safety measures called for after the Sept. 11, 2001, terrorist attacks and following the 1979 Three Mile Island accident are in place and effective, with properly trained operators on duty. The task force will make an initial report within a month of beginning the review, the NRC said. The NRC will also conduct a deeper, six-month investigation of safety measures and preparations.

Industry officials said they understood that Charles Miller, director of the NRC office overseeing environmental management programs, will head the task force. The report was not confirmed by the NRC yesterday.

The NRC review will include whether current battery backup capabilities are adequate to keep power supplied to emergency cooling systems for reactors and spent fuel storage, Borchardt said.

Trying to impart lessons learned at Fukushima

The ongoing crisis at the Fukushima Daiichi nuclear complex resulted from a loss of outside electric power and backup diesel generation following the tsunami, and then the exhaustion of backup batteries. Essential cooling systems were inoperable, leaving Tokyo Electric Power Co. (TEPCO) defenseless as the tops of fuel rods in three reactor cores overheated and failed. The power loss also led to fires and radioactivity releases from four spent fuel pools.

The NRC issued a "station blackout" requirement in 1988 that directed nuclear plant operators to assure their ability to safely shut down reactors in the event of a complete and sustained loss of outside electric power. Backup diesel generators had to be protected against earthquakes, flooding, or major fires and explosions, the NRC said.

But the backup battery protection lasts for only four to eight hours, depending on the plant. The assumption was that in that time, diesels could be put into operation or power from the outside grid could be restored. Those scenarios will be re-examined, Borchardt said.

The blackout "rule" required plant operators to assess their vulnerability to a loss of outside power and prepare a response. "It doesn't impose regulatory requirements on an ongoing basis," Borchardt said.

"We think the U.S. reactors comply with the station blackout rule. They've done the evaluations. ... They have batteries that are tested. We know they are capable. The question of how long they need to be operable is a very good question. That's clearly one of the things we're going to be looking at," Borchardt said. "We ought to take a close look and make a determination as to what the minimum time period they need to stay operable is."

Representatives of the Nuclear Energy Institute, the nuclear power industry's primary trade group, and the Union of Concerned Scientists, an industry watchdog group, agreed that an inquiry on this front was called for.

"The station blackout rule, to the NRC and the industry's credit, did significantly ... improve safety," David Lochbaum, director of the UCS's nuclear safety project, told the Senate committee. "What Japan shows is that when the event lasts longer than our assumptions, either four or eight hours, we shouldn't leave the operators with no choices" other than hoping for a miracle. "Miracles are great, but you can't rely on them," he said.

Anthony Pietrangelo, the NEI's chief nuclear officer, said the blackout rule was "one of the obvious places we'll have to look." He said the massive failure of all the Fukushima plant's backup diesels due to the tsunami is "hard to postulate" happening in the United States. "It's very, very unlikely to occur" at the same time that the electrical grid and other infrastructure around a plant are destroyed, leaving the plan cut off from emergency power, he said.

But the current four- to eight-hour backup battery capability should be reconsidered, he said. "To get to 48 hours, or 72 hours -- pick a number; we're going to take a hard look at that and see what resources would be necessary to extend the capability that long."

Concerns about spent fuel pools

At yesterday's hearing, Lochbaum renewed UCS's call for NRC regulation requiring nuclear plant operators to move spent fuel out of water pools after an initial five-year cool-down, transferring the fuel assemblies to dry cask storage in concrete containers. Thinning out the spent fuel pools lessens the risks of radioactivity releases if the pool cooling systems fail or are disabled, he said.

Borchardt said, "the NRC staff has done a thorough review of storage in the spent fuel pools and storage in dry casks. We've concluded that they're both safe. So I think from a technical safety regulation [standpoint], we wouldn't weigh in." But the NRC may consider whether accelerated transfers of spent fuel to dry cask storage add a significant safety margin, he indicated. "I think [that's] a policy question that will obviously be raised over the next months and year," he said.

Maria Korsnick, chief nuclear officer of Baltimore-based Constellation Energy Nuclear Group, said the Japan crisis has prompted a review by her company of the emergency response measures undertaken since the 9/11 attacks.

Following 9/11, Constellation and other U.S. companies added equipment to strengthen their nuclear plants' ability to withstand large fires and explosions that could follow an aircraft crash, she said in an interview. The steps included new portable generators and hose units to move water to spent fuel pools or damaged reactors in emergencies. Now, she said, "Maybe I want more portable equipment. Maybe I want to store it in more places.

"We're going to take a look at our severe accident guidelines."

The nuclear industry has endorsed the NRC's task force inquiry as a way to extract lessons from the Japan's crisis. But it also insists its plants are safe today.

In testimony prepared for a Senate Appropriations subcommittee hearing, industry executive William Levis, president and chief operating officer of PSEG Power LLC, based in New Jersey, described the nuclear industry's confidential program of safety inspections by industry officials of each others' plants and practices.

U.S. industry's private safety inspectors

The industry created the Institute of Nuclear Power Operations (INPO) following the Three Mile Island reactor accident in 1979. Based in Atlanta, INPO has a staff of 350 people monitoring nuclear plant operations daily. It works through peer pressure, Levis said in the prepared testimony that was available yesterday on NEI's website. INPO's findings are not made public.

"INPO is empowered to establish performance objectives and criteria, and nuclear operating companies are obligated to implement improvements in response to INPO findings and recommendations," Levis said. "INPO evaluates every U.S. nuclear plant every two years, and deploys training teams to provide assistance to companies in specific areas identified as needing improvement during an evaluation."

INPO requires companies to report equipment problems into an INPO database called EPIX, which reactor operators draw on to assess the probability of equipment failures, so that preventive steps can be taken, he said. The NRC has also used the database in its analysis.

"INPO also maintains a system called Nuclear Network that allows companies to report and share information about operating events, to ensure that an unexpected event at one reactor is telegraphed to all, to ensure that an event at one plant is not repeated elsewhere, to ensure high levels of vigilance and readiness," Levis said in his prepared testimony.

Korsnick said the privacy of the INPO process is the reason for its effectiveness.

Her company came under criticism this month by the Union of Concerned Scientists for an unplanned shutdown of both reactor units at its Calvert Cliffs plant in Maryland a year ago, documented by NRC inspectors and made public by the NRC. Constellation also owns nuclear plants on Lake Ontario in New York state.

Leaky roof causes 2 Md. reactor shutdowns

The incident involved rainwater leaking through a roof at an auxiliary building, which caused an electrical short shutting down one of four pumps that circulate water the reactor core of Unit 1. That caused an immediate shutdown of the reactor. The electrical failure led to an over-current in the second reactor unit, and it, too, shut down automatically. Emergency diesel generators came on, UCS said, but the Unit 2 diesel shut down after only 15 seconds. A signal indicated low lubricating oil pressure.

The problem spread to reactor pressurizers that play a key role in removing heat from the reactor, UCS said, requiring operators to use other emergency equipment, including a steam turbine-driven pump unit to control heat from the shut-down Unit 2 reactor.

The NRC singled out Constellation for failing to fix the long-standing roof leak and not adequately dealing with the replacement of aging electrical equipment involved in the Feb. 18, 2010, incident. Korsnick said those criticisms have been addressed.

"There are alternative actions the operators can take" when the incident occurred, she said. Operators "followed their training. They did what they were supposed to do. The reactors remained stable." But the incident and the NRC inspection served their purpose, she added. "We've learned a lot. ... We have to be more aggressive [on potential safety issues]. It was an opportunity for us to do that."

The INPO oversight serves a different, complementary purpose to the NRC inspections, she said.

"The peer evaluations and judgments that are made, I think, it's appropriate [to keep] within the industry. It can be very candidly written," she said. If the inspections and plant evaluations by INPO were to become public, "it changes the conversation you create." INPO's aim is creating peer pressure within the industry to achieve best practices and excellence, which can be different from meeting regulatory standards, she said. "It brings a different perspective."