Westinghouse AP1000 Passive Safety

The Westinghouse AP1000TM pressurized water reactor (PWR) is a Generation III+ two-loop 1134 MWe simplified plant design. It uses passive safety systems to provide significant and measurable improvements in plant simplification, safety reliability, investment protection, and plant costs. The AP1000 uses proven technology which build on 40 years of operating PWR experience. The AP1000 received Final Design Approval from the United States Nuclear Regulatory Commission (U. S. NRC) in 2004, and received Design Certification in 2005. The AP1000 and its predecessor, the AP600, are the only nuclear reactor designs using passive safety technology licensed anywhere in the world. The safety performance of the AP1000 has been verified by extensive testing, safety analysis, and probabilistic safety assessment. The AP1000 safety margins are large, and the potential for accident scenarios that could jeopardize public safety is extremely low. Simplicity, a key technical concept behind the AP1000, makes it easier and less expensive to build, operate, and maintain. Simplification also provides a hedge against regulatory-driven operations and maintenance costs by eliminating equipment subject to regulation. The greatly simplified design of the AP1000 complies with U. S. NRC regulatory and safety requirements and the Electric Power Research Institute (EPRI) Advanced Light Water Reactor (ALWR) United Kingdom and the Republic of South Africa. The purpose of this paper is to introduce the passive safety features unique to the AP1000 and describe their function in mitigating design basis accident sequences and severe accidents