As the nuclear power industry amps up attention to safety, operators at the Kewaunee Power Station last week moved uranium rods once used in the reactor into a hardened concrete cask outside the reactor building.
Each cask contains more than 5,000 rods that have spent years in a spent fuel cooling pool inside the reactor, located along Lake Michigan east of Green Bay.
The move wasn't linked to the Japanese nuclear disaster at the Fukushima Dai-ichi power plant this spring, but it is a step that Dominion Resources Inc. took to ensure the safety of the plant and its ability to keep operating for decades to come.
The Kewaunee plant's spent fuel pool was filling up and would not have been able to accommodate any more of the nuclear waste by 2013 if Dominion had not started moving the rods, said plant spokesman Mark Kanz.
"We're trying to create additional space in our spent fuel pool, which was getting near capacity," he said.
Opening up space now enables Dominion to move all of the fuel rods from inside the reactor core to the pool during refueling, Kanz said. "One of our main concerns was that we would have enough space in the spent fuel pool to be able to do a full core offload, if necessary, and this will give us more than enough to do that," he said.
The transfer of radioactive waste from one of Wisconsin's three operating nuclear reactors comes at a time when nuclear plants are under increased scrutiny in the aftermath of the Japanese disaster, the worst nuclear accident since Chernobyl.
The Nuclear Regulatory Commission this month released a report assessing the ability of U.S. reactors to respond to extreme emergencies such as flooding, fires and earthquakes.
Coming under scrutiny in the report are reactors' spent fuel pools as well as their preparedness for responding to power loss, fires, floods and earthquakes.
Radiation can be released from spent fuel pools if water levels are not kept above the assemblies that contain the used nuclear fuel.
Because the government has abandoned plans to build a nuclear waste storage site in Nevada, spent fuel will stay on site – whether in spent fuel pools or in hardened casks outside the reactors.
The NRC is recommending that power plant operators take extra precautions to ensure that water remains in the pool in the event of an emergency.
Nuclear safety watchdogs at the Union of Concerned Scientists want the nuclear industry to go further by removing all fuel from pools if it has been there at least five years. The organization recommends that as much spent fuel as possible be moved from pools to casks, which are better able to contain the radiation safely.
Because they are so hot when they first leave the reactor, the spent fuel assemblies need to stay in the pool for five years, said David Lochbaum, director of the group's Nuclear Safety Project.
"The known hazard of irradiated fuel stored in wet pools is going to be around for a while," Lochbaum said. "So we need to take steps to better manage that risk, rather than wait for some disaster to then compel us into taking the steps that we should have been taking."
In addition, U.S. reactors' spent fuel pools are much fuller than those at the Fukushima reactor. The reactors in Japan had hundreds of assemblies; the average U.S. spent fuel pool is three-fourths full, with about 3,000 assemblies, according to the NRC.
Lochbaum says the United States also should consider expanding the 10-mile emergency evacuation zones – to be used in the case of a severe accident – around U.S. plants. During the Japanese crisis, the U.S. government recommended that Americans in the area move at least 50 miles from Fukushima, leading to questions about whether wider emergency planning zones around U.S. reactors are needed.
The NRC's Fukushima review did not recommend any such change.
Japan led to changes
While most U.S. reactors aren't in seismically active areas such as the Pacific Ocean's "Ring of Fire," the NRC report nonetheless wants all U.S. nuclear reactor operators to review their vulnerability to earthquakes and flooding every 10 years.
Representatives of the companies operating Wisconsin's reactors, which are among the oldest in the country, said they plan to review the report for possible changes but stressed they have already made several enhancements since the disaster in Japan.
Dominion, which operates Kewaunee, and NextEra Energy Resources, which operates the two-reactor Point Beach plant, both conducted safety reviews immediately after the Japan disaster.
"In the past 90 days, we have re-verified all of our severe accident strategies and equipment to ensure they meet or exceed industry and federal safety requirements," NextEra said in a statement. "This review reconfirmed that Point Beach can be maintained in a safe condition even during a total loss of electric power, flooding, fire, explosions and other natural or man-made occurrences."
NRC recommendations
NRC inspectors reviewed the plants' preparedness and identified a number of specific items that need to be addressed at Kewaunee and Point Beach, including better coordination between the plants if both are experiencing extreme emergencies.
Plant-specific findings included a need for Point Beach to test and charge batteries for portable equipment, to procure spare hoses to keep water flowing into the spent fuel pool, and to re-evaluate procedures for transporting water to the pool.
Kewaunee operators were asked to consider replacing a fire door that may not be fireproof and to address the fact that its hydrogen recombiners – equipment used to minimize the risk of a reactor explosion – were stored off-site and would require some lead time to be delivered to the plant.
The NRC said it would release more findings related to its plant-specific reviews as part of its next quarterly inspection reports.
It's unclear how quickly changes will need to be made as a result of the review conducted by the NRC. In a speech last week, NRC Chairman Gregory Jaczko said he would like to see all 104 U.S. reactors meet a deadline of having all upgrades linked to the Japan catastrophe in place within five years.
Lochbaum said it will be important for the NRC to hold nuclear plants to a deadline, noting that plants including those in Wisconsin are not meeting fire protection standards developed in 2004. In addition, not all of the recommendations to shore up nuclear plants after the Sept. 11, 2001, attacks have been put in place, Lochbaum said.
The NRC review had special recommendations for boiling water reactors that share the same design as the Fukushima Dai-ichi reactors. But the Wisconsin reactors are pressurized water reactors and were built using a different design.
