Reactor Design and Decommissioning - An Overview of International Activities in Post Fukushima Era 1 -12396

Accidents at the Fukushima Dai-ichi reactors as a result of the devastating earthquake and tsunami of March 11, 2011 have not only dampened the nuclear renaissance but have also initiated a re-examination of the design and safety features for the existing and planned nuclear reactors. Even though failures of some of the key site features at Fukushima can be attributed to events that in the past would have been considered as beyond the design basis, the industry as well as the regulatory authorities are analyzing what features, especially passive features, should be designed into the new reactor designs to minimize the potential for catastrophic failures. It is also recognized that since the design of the Fukushima BWR reactors which were commissioned in 1971, many advanced safety features are now a part of the newer reactor designs. As the recovery efforts at the Fukushima site are still underway, decisions with respect to the dismantlement and decommissioning of the damaged reactors and structures have not yet been finalized. As it was with Three Mile Island, it could take several decades for dismantlement, decommissioning and clean up, and the project poses especially tough challenges. Near-term assessments have been issued by several organizations, including the IAEA, the USNRC and others. Results of such investigations will lead to additional improvements in system and site design measures including strengthening of the antitsunami defenses, more defense-in-depth features in reactor design, and better response planning and preparation involving reactor sites. The question also arises what would the effect be on the decommissioning scene worldwide, and what would the effect be on the new reactors when they are eventually retired and dismantled. This paper provides an overview of the US and international activities related to recovery and decommissioning including the decommissioning features in the reactor design process and examines these from a new perspective in the post Fukushima -accident era. FUKUSHIMA DAI-ICHI: NEAR-TERM IMPACT ON NUCLEAR RENAISSANCE Fukushima area in the eastern coast of Japan experienced a magnitude 9 earthquake and large tsunami waves on March 11, 2011 that caused widespread devastation with more than 20,000 lives lost, and caused the nuclear accident at Fukushima Dai-ichi reactor complex. The loss to Japan's economy (including from the nuclear accident) is estimated in excess of $100 billion. The Fukushima nuclear accident has been categorized at the highest rating on the International Nuclear Event Scale, similar to the Chernobyl rating. The accident severely damaged the reactor complex.