Japan Moves Forward after Fukushima’s Accident
Sendai Nuclear Station Okayed to Operate – Others May Be Decommissioned
Nearly three and a half years after the Fukushima Daiichi’s nuclear accident, Japan’s Nuclear Regulation Authority has certified its first nuclear station at Sendai to go back on line while recommending that plants older than 40 years be considered for decommissioning. Critics say the decision is driven by government desire to reduce expensive fuel imports that compensate for Japanese electricity production formerly supplied by nuclear power. Is public safety being sacrificed for economic growth? Or is the government acting with long-term energy needs in mind?
The U.S. nuclear industry found itself in a similar situation after the Three Mile Island Unit 2 (TMI-2) accident in 1979. As a result of TMI-2, new plant severe accident management guidelines and severe accident computational methods and tools were developed. Control room operators and shift technical advisors in U.S. commercial nuclear facilities were required to pass comprehensive severe accident training requirements and annually qualify to manage severe nuclear accidents that exceed the design basis accidents typically analyzed in power plant final safety analysis reports. Moreover, nuclear power plants (NPPs) probabilistic risk assessment studies expanded their scopes beyond quantifying plant risk due to internal events to include vulnerability to external events (such as tornadoes, high winds, external fires and external floods, seismic events, etc.).
The post TMI-2 measures have apparently worked. Nothing similar to Three Mile Island accident has re-occurred in the United States since 1979, even as nuclear power has grown to supply half the power demands of many states including New Jersey, Connecticut, South Carolina and Illinois. A 2013 study in Environmental Science and Technology demonstrates that air quality gains attributable to utilization of nuclear power versus fossil fuel have prevented an estimated 1,000,000 deaths worldwide. Moreover, the US Nuclear Regulatory Commission has approved extending NPPs life from the original 40 years’ operating license to 60 years. Many of the US commercial nuclear fleet went ahead with submittals for plant life extension.
Until the earthquake and tsunami struck Fukushima 3 ½ years ago, Japan had 48 operating commercial nuclear reactors that the World Nuclear Association reported as providing about 30% of Japan’s electricity. The nation planned to expand its reliance on nuclear to at least 40% by 2017. With the technology to enrich nuclear fuel and reprocess spent high-level waste, Japan was poised to build the next generation of advanced light water reactors that include passive safety systems.
Japan’s strategy to gradually restart its commercial nuclear fleet is a step in the right direction now that regulators and nuclear utilities have incorporated lessons learned from the Fukushima Daiichi accident into revised and improved power plant safety standards and emergency operating procedures. While Japan NPPs certainly need to strengthen their plant-specific probabilistic risk assessment studies to address the seismic vulnerabilities revealed by the Fukushima Daiichi’ accident, the world needs to take note of how they do it as well as the innovations they develop with future designs that may follow. The latest Intergovernmental Panel on Climate Change report gives the world a 15-year window to seriously address the issue of greenhouse gas emissions. With so little time we’re going to need Japan and the new improved technologies they can produce to get us there.
 Pushker A. Kharecha and James E. Hansen. NASA Goddard Institute for Space Studies and Columbia University Earth Institute, 2880 Broadway, New York, New York 10025, United States. Environ. Sci. Technol., 2013, 47 (9), pp 4889–4895