On Nrc Proposed Rule " Consideration of Airctaft Impacts for New Nuclear Power Reactor

Using a modern design for a nuclear power plant as a point of departure, this study examines the enhancement of protection which may be achieved by changes to the des ign and the impacts associated with the changes. These changes include concepts such as complete physical separation of redundant trains of safety equipment, hardened enclosures for water storage tanks, and hardened shutdown heat removal systems. The study examines the enhancement (value) in terms such as the potential reduction in the number of vital areas and the increase in probability of adversary sequence interruption. The impacts considered include constraints imposed upon operations and maintenance personnel and increased capital and operating costs. The study results indicate that design changes alone do not provide significant enhancement of protection against sabotage. However, some of the design alternatives can facilitate the implementation of effective physical protection systems for both insider and external threats. Design changes that limit access and reduce outside access are practical only for new plants. A promising alternative considered is a hardened decay heat removal system, which provides primary coolant makeup and feedwater to the steam generators of a pressurized water reactor plant. Such a system has potential fo. incorporation Into now plants.