Suzette Payne is a seismologist at the Idaho National Laboratory, east of Arco.
By SUZETTE PAYNE
The recent earthquake in northern Japan and the impact to a commercial nuclear power plant there have been followed with interest by Idaho National Laboratory officials. We know there have been earthquakes in the region around the INL, so we believe it is appropriate to discuss the safety of the INL site.
In the past, incorrect inferences have been made relative to the assumptions used in analyzing the Advanced Test Reactor's response to a seismic event. These inferences served to confuse and alarm some who do not understand the enormous rigor applied in the design of nuclear facilities. We are confident based on many reviews by internationally recognized technical experts that the Advanced Test Reactor is safe.
The Snake River Plain has been extensively studied for more than 40 years by our experts and by other government agencies, universities and industry. Our staff of seismologists and geologists continually collect information through our extensive INL Seismic Network. Their findings are reviewed and validated by independent, professional peers.
From these studies, we know that the Snake River Plain is much less seismically active than the surrounding mountains. A review of historical earthquake activity on and around the Snake River Plain provides a good indication of the relatively low rate of earthquakes in the Snake River Plain compared to the surrounding mountains.
During the 1959 Hebgen Lake, Mont., earthquake, which measured a magnitude of 7.5, there was no damage to INL facilities, though it was felt on site. And the 1983 Borah Peak, Idaho, earthquake, which measured 7.3, was also felt on the INL. But, again, there was no damage to our facilities, including the Advanced Test Reactor.
The Advanced Test Reactor was built to conservative seismic standards current at the time of its construction. As seismic analysis techniques have improved and as lessons are learned from events such as the recent earthquake in Japan, the Advanced Test Reactor, as well as other key laboratory facilities, are reevaluated against the new information. In the past there have been modifications to the facility to comply with evolving safety standards. INL is currently conducting a comprehensive structural evaluation of the reactor and considering the potential for and severity of an earthquake at the reactor site using the most current seismic and geologic information. What we've found so far is that the Advanced Test Reactor is well built as designed and maintained, and upgrades completed to meet the newest safety margins have been relatively minor.
The Advanced Test Reactor's structural design is governed by the U.S. Department of Energy's Natural Phenomena Hazards Standards. For facilities such as nuclear facilities, these standards are more rigorous than the standards for other facilities. The standards are comparable in terms of analytical rigor to Nuclear Regulatory Commission requirements for commercial nuclear power plants.
Anyone wishing to learn more about INL and the Advanced Test Reactor is welcome to visit and ask our engineers and scientists hard questions about the laboratory and the reactor. You can schedule a tour through our Web site at www.inl.gov.
