SEABROOK — The Nuclear Regulatory Commission has issued the first set of orders meant to prevent the kind of disaster that engulfed Japan's Fukushima Daiichi nuclear power plant last year, and Seabrook Station nuclear plant will be required to make changes in its safety systems.
According to Neil Sheehan, spokesman for the NRC's Region 1, the first two orders were issued to all power reactor licensees in the nation. The third order is for plants that use a system called boiling water reactors, which was the type of reactor used at Fukushima. The Seabrook nuclear power plant uses a different technology, called a pressurized water reactor.
The NRC's first order requires all power plants to develop strategies to mitigate the effects of "beyond-design-basis natural phenomena," such as earthquakes, tornados, flooding, hurricanes, etc., to address multi-unit events and reasonable protection of equipment needed to implement strategies. This particular order deals with external events resulting in loss of power and loss of normal access to the plants' "ultimate heat sinks," which is the body of water from which it draws water for cooling purposes and where it subsequently discharges that water at a slightly higher temperature, Sheehan said.
For Seabrook, the ultimate heat sink would be the Atlantic Ocean. Seabrook has long pipes that draw water from about a mile offshore.
Plants are being ordered to provide capabilities to supplement those already permanently existing in the facilities, should those already installed become unavailable due to natural phenomena.
"The strategies will add multiple ways to maintain or restore core cooling, containment and spent fuel pool cooling capabilities in order to improve the defense in depth of licensed nuclear power reactors," Sheehan wrote in his summary of the orders. "(It) also requires that the equipment needed to implement the strategies be reasonably protected."
The order relates directly to the problems that affected the Fukushima Daiichi plant, which caused the meltdown of the cores of three of its seven reactors. When the 9-magnitude earthquake shook the ground under the Fukushima nuclear complex, it cut its power. The subsequent tsunamis flooded the complex's backup generators, which were closer to the water and at a lower elevation than the reactors.
The extended power outage and the inability of the plant to produce its own power to run its safety and cooling systems failed to keep the nuclear cores cool, causing the meltdowns.
At Seabrook, there are currently layers of power backup systems that can each run the plant's safety and cooling systems. They include three independent diesel generators, an additional reactor cooling system powered by steam generated by the plant itself, backup on-site batteries for critical safety systems, external cooling options pre-staged on-site, the ability to use nearby ocean water for cooling, and a power supply that allows cooling systems to be powered for seven days without requiring any off-site power or additional fuel.
In its second order to all nuclear power plants, the NRC mandates that nuclear plant licensees install enhanced Spent Fuel Pool (SFP) instrumentation that will allow operators to know if the pools are having problems maintaining cooling.
This order also relates to the events at Fukushima Daiichi. Those responding to the problems there didn't have reliable instrumentation to determine the water level in the SFP, Sheehan said.
"This caused concerns that the pool may have boiled dry, resulting in fuel damage, but in fact the spent fuel had remained covered at all times," Sheehan wrote. "Fukushima demonstrated that confusion and misapplication of resources may result from beyond-design-basis external events when adequate instrumentation is not available."
Seabrook Station has both a spent fuel pool and dry storage of spent nuclear rods.
The new NRC requirements will enhance instrumentation installed at U.S. nuclear power plants, Sheehan said.
According to the NRC, the likelihood of a catastrophic event affecting U.S. nuclear power plants and their spent fuel pools remains very low, but external events could challenge the ability of existing pools' instrumentation to provide emergency responders with reliable information, which is "essential to ensure that plant personnel can effectively prioritize emergency actions."
On March 12, the NRC also requested four written reports from all power plants on the re-evaluation of seismic and flooding hazards at each site using the most current data, the performance of seismic and flooding walk downs to address plant-specific risks, the assessment of communication systems and equipment under damaged and prolonged power outage situations, and the performance of staffing studies to determine the number and qualifications of staff needed to fill all necessary positions when responding to a multi-unit event.
The NRC hopes to implement the technical requirements for the orders by August. Licensees must submit plans on how they will comply with the orders by Feb. 28, 2013. After review of the plans, the NRC will issue facility-specific orders, as necessary, imposing license conditions that address the requirements of the orders. Each licensee must then comply within two refueling outages or Dec. 31, 2016.
NextEra Energy Seabrook's spokesman Alan Griffith said that while the plant is pleased that the NRC confirms America's nuclear plants pose no imminent hazard to public safety, since the Fukushima disaster, the owners of the plant in Seabrook have taken steps to improve the plant's seismic safety.
"Since the events in Japan, Seabrook Station has reverified our severe accident strategies and equipment to ensure they meet or exceed industry and federal safety requirements," Griffith said. "Seabrook has already taken proactive steps to begin addressing the enhancements issued by the NRC (in its recent orders). In fact, we have already invested nearly $1 million to add additional layers of safety equipment and incorporated lessons learned from the Fukushima event in our plant operator and emergency responder training programs."
Compliance with the post-Fukushima order and requests for information will not, however, be a factor in license renewal decisions, Sheehan said. NextEra Energy Seabrook currently has an application before the NRC to have its license to operate extended from 2030 to 2050.
"The commission has already made clear in rulings on several post-Fukushima contentions that it believes the plants can continue to operate safely as the changes required by the agency in the aftermath of Fukushima are implemented," Sheehan said.