Keywords: International Reactor Innovative and Secure, IRIS light water reactors, safety-by-design, emergency planning, emergency planning zones, EPZ, licensing, advanced reactors, integral reactors, LOCAs, core damage frequency, CDF, defence in-depth, PRA, nuclear power plants, nuclear energy, risk management, emergency management, nuclear accidents, risk assessment
IRIS safety-by-design? and its implication to lessen emergency planning requirements
International Reactor Innovative and Secure (IRIS) is an integral configuration pressurised light water reactor that has been in development since late 1999 by an international consortium. Its design and safety characteristics have been amply reported. In this paper the safety-by-design? IRIS philosophy is reviewed to show how the projected safety performance (most accidents either eliminated or inherently mitigated, Core Damage Frequency (CDF) due to internal events of the order of 10−8 events/year) exceeds the current norm of nuclear reactors. The IRIS project plans to use this enhanced safety response to explore the possibility of lessening, or even eliminating, the off-site emergency planning requirement. A review is given of previous attempts to attain this relaxation of licensing regulations and of current goals for advanced reactors. Finally, the proposed methodology is outlined. It consists of a combined deterministic and probabilistic approach, including a review of the defence in-depth, and a risk informed analysis of a wide spectrum of accidents, rather than an evaluation limited to a few design-based accidents.