Response to the Fukushima Nuclear Accident
ORNL helps collect, analyze and interpret available data
On March 11, 2011, a massive earthquake and tsunami struck Japan. The tsunami knocked out critical power and cooling systems at the Fukushima Daiichi and Daini nuclear power plants, leading to significant damage to three operating nuclear reactors and one that was shut down for maintenance. Damage included melted fuel, hydrogen explosions and leakage of highly contaminated water into support buildings and the surrounding environment.
Responding to the Fukushima Nuclear Accident.
In the days after these events, the Department of Energy closely monitored the situation. DOE staff and experts from ORNL and other national laboratories helped collect, analyze and interpret the available data. These preliminary assessments were compared with similar analyses performed by the nuclear industry and the Nuclear Regulatory Commission for consistency. DOE provided this information to Japan through the U.S. embassy. More recently, DOE has provided additional assessments at the request of the Japanese government.
ORNL continues to play a key role in developing these assessments. Hundreds of laboratory staff members from a variety of disciplines have applied their expertise and analytical skills to the task of supporting the international response to the events at Fukushima.
Key areas of support have included the following:
- Severe accident management assessment, simulations, and mitigation strategies, including insights from U.S. operating experience
- Assessment of support structures and other infrastructure concerns beyond the reactor buildings
- Data collection of key plant parameters, particularly tracking water injection and water levels
- Translation of key plans and documents from Japanese
- Causal analysis of the explosion in the spentfuel pool in Fukushima Daiichi unit 4
- Extensive simulation of the conditions in spent-fuel pool in Fukushima Daiichi unit 4
- Expert advice on robotic tools used for remote surveillance and monitoring
- Chemistry expertise on seawater composition and effects
- Impacts of seawater on corrosion of key reactor components and systems
- Analysis of the reactor pressure vessel integrity
- Analysis of radioactive releases and input on atmospheric monitoring data
- Input and analysis of alternative cooling strategies for long-term stability at the Fukushima Daiichi units
As of early June, the situation at the Fukushima Daiichi nuclear plant had stabilized significantly. However, the Japanese government still faces challenges related to shutting down the reactors and cleaning up the site. DOE will continue to provide analyses and assessments of these events. ORNL's diverse expertise and professional approach to the situation have been critical to DOE's response to the Fukushima nuclear accident to date and will continue to play an important role in the department's future efforts.—Jeremy Busby