Nuclear power plants have been inundated by flood waters and Tsunamis, pummeled by tornadoes, and rattled by earthquakes. Since the early 1970s, the IAEA has been developing Safety Standards for nuclear power plant siting that include the risks external events pose to the plant's safe operation under all conditions. During the past two decades, over 100 IAEA expert missions have investigated and reviewed nuclear installations' ability to withstand strong earthquakes.
When a massive Tsunami hammered India's east coast in December 2004, its waves submerged some of the sea water pumps at the Madras Atomic Power Station Nuclear Power Plant. In July 2007, the Niigate Chuetsu-Oki earthquake hit the world's largest nuclear power plant, Kashiwazaki-Kariwa, which was damaged by the tremors. These two events fused international action to intensively monitor and research these extreme events.
By 2008, the IAEA established the International Seismic Safety Centre (ISSC). The Centre's expertise lies in supporting Member States in their assessment of external hazards when selecting nuclear power plants sites, to evaluate existing plants' robustness against such hazards and to develop more robust plant designs.
"The ISSC plays a leading role in supporting nuclear safety globally," said Denis Flory, the IAEA's Deputy Director General for Nuclear Safety and Security, speaking at a recent ISSC meeting. "The ISSC's work and research on external events such as earthquakes, Tsunamis, tornadoes, and flooding offers the sound, scientifically-proven basis for the effective implementation of best practices in seismic safety."
Great East Japan Earthquake
On 11 March 2011, Flory recalled, "the ISSC's External Event Notification System alerted the IAEA's Incident and Emergency Centre (IEC) within 56 minutes of the Great East Japan Earthquake's first tremor. That warning enabled the IEC to immediately initiate an international emergency response."
Less than an hour later, the earthquake-driven Tsunami devastated the eastern Japanese coast, cutting power, control and cooling at the Fukushima-Daiichi Nuclear Power Station, triggering the severe nuclear accident. During the IAEA's emergency response, the ISSC's experts helped plan and conduct the IAEA's first fact-finding mission to the accident site. With those findings in hand, the ISSC supported the development of an IAEA methodology to assess specific nuclear power plants' resilience against extreme natural hazards. The Centre's experts returned to Japan early in 2012 to use this methodology to assess whether the nuclear power plants shut down after the March 2011 earthquake and Tsunami could be safely re-started.
As the IAEA coordinated the emergency response, the Agency's experts also worked intensively on a Nuclear Safety Action Plan that all of the IAEA's Member States adopted the in September 2011. Comprising 12 key actions to strengthen safety at nuclear power plants around the world, the Nuclear Safety Action Plan, Flory emphasized, is supported substantially by the ISSC, which is undertaking "exactly the kind of work that is needed by the Action Plan: the ISSC supports Member States in promptly initiating the national assessment of site-specific external natural hazards, reviewing and revising Safety Standards on nuclear power plant site selection and the assessment of external natural hazards, strengthening the emergency notification systems and reporting, disseminating the lessons learned from the Fukushima accident and strengthening Member States' capacity."
Funded solely by voluntary contributions, the ISSC depends upon the support of IAEA Member States to act as a global focal point in strengthening safety against external hazards for nuclear installations world-wide. Flory underscored the Nuclear Safety Action Plan's "pivotal role in prioritizing the Agency's work and that of the ISSC, which is funded as an extra-budgetary project."
For a week from 6 to 10 February 2011, the Centre's donors meet in Vienna to discuss the range of research, review services and training the Centre is delivering.
For a donor nation, such as the Republic of Korea, addressing the hazards posed by external events is vitally important, said Chang-Hun Hyun, the Principal Research Engineer of the Korea Institute of Nuclear Safety, since "the ISSC's objectives are important for all countries that are now using nuclear power." Hyun emphasized that Korea values, the ISSC's work, because "we directly utilize the safety reports and the technical documentation, in strengthening seismic safety."
Intensively involved in establishing the ISSC as part of Japan's contribution to ensure the highest levels of seismic safety, Katsumi Ebisawa, Associate Vice-President of the Japan Nuclear Energy Safety Organization, sees the ISSC as "the global watchdog for ensuring the safety of nuclear power against external events." Since the ISSC is part of the IAEA, an independent, international organization, Ebisawa noted that the ISSC is "best suited to assess seismic safety for embarking countries that wish to introduce nuclear power for the first time."
It is the ISSC's capacity to bring together a broad range of stakeholders that Philippe Renault, Swissnuclear's Head of Earthquake Safety and Probabilistics, values as "a platform to exchange lessons learned between regulators, industry and operators regardless of their origin." External hazards represent one of the first challenges a Member State has to consider before embarking on a nuclear power programme. Switzerland, Renault explained, "has done a great deal in this area and we wish to share that knowledge, especially with nuclear newcomers." The ISSC organizes this information centrally so that Member States can easily access it, Renault noted, "to be able to compare the ISSC's technical reports with national regulation and then extract the benefits from lessons learned by other countries."
Nuclear safety's continual improvement is the fundamental priority driving the Centre's work, said Pierre Labbe of Électricité de France, since "otherwise nuclear safety will regress." While the IAEA develops and issues Safety Standards, it is the ISSC's detailed documentation that provides "exactly the kind of guidance that nuclear reactor operators need to be able to effectively implement the seismic Safety Standards," Labbe explained.
The ISSC also develops IAEA Safety Standards and supports their use in selecting sites for nuclear power plants, evaluating existing sites to determine hazards caused by natural events, seismic design, and through expert safety review services tailored for Member States' individual requirements. The ISSC's Siting and External Events Design review (SEED) is designed to determine whether a Member State's site selection and plant safety design is consistent with international practices and to confirm that conclusion through an international peer review.
Several countries are embarking on programmes to introduce nuclear power. For these nations, the IAEA's safety guide on the types of seismic hazards to consider when planning the site of a future nuclear power plant offers vitally important guidelines. The ISSC is now translating that guidance into a detailed guide on the advice's practical implementation, such as predicting site response and ground motion, producing a database of the environmental effects of earthquakes, and analyzing the ancient, or "paleoseismological" record of seismic events.
For the nuclear power plants now in operation, the ISSC is developing detailed, updated guidance for regulators' and operators' use in evaluating existing nuclear power plants' seismic safety. That advice includes a database of experience with seismic activity, a benchmark study of the Kashiwazaki-Kariwa Nuclear Power Plant's response to the 2007 earthquake, as well as a real-time safety assessment system to evaluate a nuclear power plant's response when subjected to seismic and other external events.
Flooding can threaten a nuclear power plant's safe operation. The ISSC is reviewing the safety guidance on assessing flooding hazards, coordinating global and regional cooperation in tsunami hazard assessment and is encouraging the installation of the Tsunami Warning System at all nuclear power plants.
Volcanoes present another relatively common external hazard, since about a quarter of the IAEA's Member States have active volcanoes within their borders. Volcanic activity can have regional and international impact, which the IAEA's safety guide on assessing volcanic hazards when siting a nuclear power plant will address. The guide is due to be issued in 2012, and will be supplemented with training courses and a workshop.
Although not a natural event, sabotage could threaten plant safety, and could cause effects similar to those produced by a natural event. An ISSC working group is now producing a detailed manual to help Member States implement security guidance to prevent sabotage.
Predicting Tsunami Impacts
In partnership with the United States' National Oceanographic and Atmospheric Administration, the ISSC is also developing a real-time Tsunami forecasting system. If an earthquake is registered that could lead to a Tsunami, the ISSC's forecasting system would utilize state-of-the-art modeling software to predict wave height and the speed with which the waves are moving across the ocean. When these predictions are matched with the locations of the nuclear facilities in the region, for instance, the waves' arrival time and height could be sent as an alert message to potentially affected facilities. An advance warning of this nature could significantly increase the facilities' ability to prepare for the ocean's onslaught.
When reviewing the past year, Sujit Samaddar, the ISSC's Head, said the International Seismic Centre "has grown into a centre of excellence on external events," including volcanic activity and tsunamis. While the ISSC provides site safety reviews for many countries now considering starting a nuclear power programme, Samaddar underscored that "the Centre's limited resources do not allow it currently to provide the level of support that is needed in Member States that are keen in progressing rapidly with their energy program." He is optimistic that a new extrabudgetary programme will be funded to channel support to "the embarking countries to assure us that all possible means national and international has been taken when siting and building new plants in countries different from countries where they were manufactured."