Comparative review of design and improved safety features of new LWR plants

This study will address the improved safety features of Advanced Light Water Reactor (ALWR) systems that are under consideration for near term deployment in the Unites States and abroad. The safety features of ALWR systems can be divided into two major categories based on their reliance on passive or active design for the emergency core cooling system. The ALWR systems evaluated in this study are actively safe ABWR, EPR and APWR, and passively safe AP 1000 and ESBWR. Each of the passive or active ALWR systems includes sign improved safety features and larger operational margins, in each of the BWR and PWR categories, actively cooled ABWR and EPR feature the lowest average LHGR. The AP 1000 and the ESBWR feature passive safety systems that use gravity-driven flow for emergency core cooling with no need for secondary power sources such as Emergency Diesel Generators (EDGs) in case of loss of o power The ABWR and the EPR both use the proven technology and use safety grade EDGs. They must be maintained and have surveillances performed like existing diesels at current nuclear reactor sites. There is also a finite probability of EDGs failing to start or to run for a variety of causes including problems associated with cooling, engine, fuel oil, generator instrumentation and control, breaker; and starting air Though the lack of safety grade EDGs in passive systems is a clear advantage, the ABWR and EPR by employing multiple and redundant EDGs and the APWR by utilizing the GTG provide for an order of magnitude safety improvement over the current generation of operating LWR reactors in US. (authors)