- Joined
- Jul 26, 2003
The US Nuclear Regulatory Commission has produced a set of answers to frequently asked questions about Japan's earthquake, tsunami and nuclear disaster:
http://www.nrc.gov/japan/faqs-related-to-japan.pdf
Answers are very complete, but in short:
1. The only part of the US where this combination of earthquake and tsunami could occur is in northern California, Washington and Oregon, which are near the Cascadia subduction zone. The only nuclear plant in this part of the country is Columbia, and it is 225 miles from the ocean, and 300 miles from the subduction zone. In other parts of the country, the maximum earthquake would be 8 . (I am thinking the writer of this piece forgot about Alaska and Hawaii...Alaska had a combo of earthquake and tsunami during the Great Alaska Earthquake, which was actually bigger than the Japanese Quake. OTOH, there are no reactors there.
The US says the tsunami in the ocean off Daini was 7 meters (22.97 feet) and off Daiichi was 8 meters (26.25 feet). They don't have the official Japanese data.
The article describes in detail earthquake, tsunami and other disaster planning that is done for nuclear sites and prospective nuclear sites in the US.
This was interesting to me:
And as to how prepared US plants are for disasters:
Does anyone know what the relevant Canadian websites and agencies are? Have they issued any updates, explanations, or so forth?
http://www.nrc.gov/japan/faqs-related-to-japan.pdf
Answers are very complete, but in short:
1. The only part of the US where this combination of earthquake and tsunami could occur is in northern California, Washington and Oregon, which are near the Cascadia subduction zone. The only nuclear plant in this part of the country is Columbia, and it is 225 miles from the ocean, and 300 miles from the subduction zone. In other parts of the country, the maximum earthquake would be 8 . (I am thinking the writer of this piece forgot about Alaska and Hawaii...Alaska had a combo of earthquake and tsunami during the Great Alaska Earthquake, which was actually bigger than the Japanese Quake. OTOH, there are no reactors there.
The US says the tsunami in the ocean off Daini was 7 meters (22.97 feet) and off Daiichi was 8 meters (26.25 feet). They don't have the official Japanese data.
The article describes in detail earthquake, tsunami and other disaster planning that is done for nuclear sites and prospective nuclear sites in the US.
This was interesting to me:
The Japanese facilities are similar in design to some US facilities. However, the NRC has required modifications to the plants since they were built, including design changes to control hydrogen and pressure in the containment. The NRC has also required plants to have additional equipment and measures to mitigate damage stemming from large fires and explosions from a beyond-design-basis event. The measures include providing core and spent fuel pool cooling and an additional means to power other equipment on site.
And as to how prepared US plants are for disasters:
22) Could an accident sequence like the one at Japan’s Fukushima Daiichi nuclear plants happen in the US?
It is difficult to answer this question until we have a better understanding of the precise problems and conditions that faced the operators at Fukushima Daiichi. We do know, however, that Fukushima Daiichi Units 1-3 lost all offsite power and emergency diesel generators. This situation is called “station blackout.” US nuclear power plants are designed to cope with a station blackout event that involves a loss of offsite power and onsite emergency power. The Nuclear Regulatory Commission’s detailed regulations address this scenario. US nuclear plants are required to conduct a “coping” assessment and develop a strategy to demonstrate to the NRC that they could maintain the plant in a safe condition during a station blackout scenario. These assessments, proposed modifications to the plant, and operating procedures were reviewed and approved by the NRC. Several plants added additional AC power sources to comply with this regulation.
In addition, US nuclear plant designs and operating practices since the terrorist events of September 11, 2001, are designed to mitigate severe accident scenarios such as aircraft impact, which include the complete loss of offsite power and all on-site emergency power sources.
US nuclear plant designs include consideration of seismic events and tsunamis’. It is important not to extrapolate earthquake and tsunami data from one location of the world to another when evaluating these natural hazards. These catastrophic natural events are very region- and location-specific, based on tectonic and geological fault line locations.
Does anyone know what the relevant Canadian websites and agencies are? Have they issued any updates, explanations, or so forth?

