By John Kotek
Former Acting Assistant Secretary for the Office of Nuclear Energy
On March 11, 2011, a magnitude 9.0 earthquake struck Japan. It was one of the most powerful earthquakes on record, unleashing a tsunami that ravaged 430 miles of coastline, destroying communities, and killing nearly 16,000 people. The combined effects of the earthquake and tsunami overwhelmed on and offsite power systems at the Fukushima Daiichi nuclear power plant, leading to the meltdown of three reactors and the release of radioactive contaminants into the surrounding environment. Five years on, the decommissioning and clean-up at Fukushima remains in the early stages and will likely take decades to be completed. In the aftermath of this multi-unit accident, the global nuclear community has been reassessing certain safety assumptions about nuclear reactor plant design, operations and emergency actions, particularly with respect to extreme events that might occur.
On the fifth anniversary of that devastating natural disaster and nuclear accident, we must be sure to remember the lives that were lost as well as those that are still displaced from their homes. I would also like to highlight the important work that the Department of Energy’s Office of Nuclear Energy is doing to respond to our industry’s worst accident since Chernobyl in 1986.
Due to its significant domestic investment in nuclear reactor technology, the United States has been a major leader in these activities, and NE has played a key role in the U.S. response to Fukushima. Initially, we worked with the Japanese and the international community to help develop a more complete understanding of the accident progression and its consequences, and to respond to various safety concerns emerging from uncertainties about the nature of, and the effects, from the accident. The U.S. nuclear industry is voluntarily pursuing a number of additional safety initiatives. The Nuclear Regulatory Commission continues to evaluate and, where deemed appropriate, establish new requirements at licensed nuclear facilities for ensuring adequate protection of public health and safety in the occurrence of low-probability occurrences such as extreme seismic or flooding events.
In response to the Fukushima accident, NE is conducting R&D activities focused on providing scientific and technical insights, data, and analyses methods that ultimately support industry efforts to enhance safety. These activities are expected to further enhance the safety performance of currently operating plants as well as better characterize the safety performance of future U.S. nuclear power plants. In pursuing this area of R&D, we recognize that the commercial nuclear industry is ultimately responsible for the safe operation of licensed nuclear facilities. As such, industry is considered the primary “end user” of the results from this DOE-sponsored work.
NE’s Fukushima-related research is focused on reducing uncertainty in our understanding of severe accident progression, phenomenology, and outcomes using existing analytical codes and information gleaned from severe accidents, in particular the accident in Japan. This information will be used to aid in developing strategies and improving accident management guidelines for the current light water reactor fleet. Our work currently is organized into three main areas:
- Accident Tolerant Components: This R&D is focused on analysis or experimental efforts for hardware-related issues, including systems, structures and components with the potential to prevent core degradation or mitigate the effects of beyond-design basis events.
- Severe Accident Analyses: This R&D is focused on analyses using existing computer models and their ability to provide information and insights into severe accident progression that aid in the development of severe accident management guidelines and/or training operators on these guidelines; an auxiliary benefit can be informing improvements in these models.
- Fukushima Forensics and Examination Plans: This R&D is focused on providing insights into the actual severe accident progression at Fukushima through visual examination and data collection of in-situ conditions of the damaged units as well as collection and analysis of samples within the reactor systems and structural components from the damaged reactors. This effort could provide substantial lessons-learned on severe accident progression, similar to those from Three Mile Island accident examinations.
The March 11, 2011 earthquake and tsunami that caused the Fukushima accident was terrible and tragic, but I am immensely proud of the role that the Office of Nuclear Energy is playing to prevent another one like it.