Fusion Science and Technology / Volume 60 / Number 1T / July 2011 / Pages 69-74
The Korean fusion technology roadmap specifies the construction of a fusion power plant at demonstrative scale by 2030. Obviously, the safety requirements for demonstration fusion reactors will be quite different and more stringent than that of experimental reactors. Nevertheless, the regulatory framework for such reactors was not fully matured due to the limited resources and the lack of technical feasibility in Korea. Sharing with the motivation, this research investigated and compared the safety characteristics of fission and fusion power plants to facilitate designing of engineered safety features. Korea has gained a vast experience over the last 30 years, regarding design, construction and operation of both pressurized light and heavy water reactors, which is useful to address the attributes for fission power plants. In case of fusion reactor technology, the operational experiences with ITER and K-STAR can be referred, considering their demonstration scale. Comparative study was performed in top-down manner. We compared the top requirements such as safety principles and defense-in-depth for fusion and fission power plants. The inherent safety parameters such as the reactivity feedback coefficients of fission power plants were investigated how these parameters would be represented in fusion power plants. The limits for operating conditions for a fusion reactor were investigated to recognize important parameters which would contribute to nuclear safety or, more specifically accident prevention. For the accidents beyond the operation limits, the need of engineering safety features was found indispensable for accident mitigation. However, it is anticipated that the engineering safety features for fusion reactors will be reduced in number, size, type, and safety-margin because the total amount of hazardous material is much lower as compared to fission reactors. Finally we proposed the table of contents of safety analysis report for fusion power plants borrowing the basic structure from the safety reports on fission reactors. The outcome of this study helps to prioritize research projects to be devoted for analyzing the safety of demonstration fusion plant, and to develop design and regulatory framework in South Korea.