A generation III reactor is a development of any of the generation II nuclear reactor designs incorporating evolutionary improvements in design developed during the lifetime of the generation II reactor designs. These include improved fuel technology, superior thermal efficiency, passive safety systems and standardized design for reduced maintenance and capital costs.
Improvements in reactor technology result in a longer operational life (60 years of operation, extendable to 120+ years of operation prior to complete overhaul and reactor pressure vessel replacement) compared with currently used generation II reactors (designed for 40 years of operation, extendable to 80+ years of operation prior to complete overhaul and RPV replacement). Furthermore, core damage frequencies for these reactors are lower than for Generation II reactors — 60 core damage events per 1000 million reactor–year for the EPR; 3 core damage events per 1000 million reactor–year for the ESBWR[1] significantly lower than the 10,000 core damage events per 1000 million reactor–year for BWR/4 generation II reactors.[1]
Proponents of the Gen III designs claim they are much safer than existing reactors in the US, but other engineers are more conservative. Edwin Lyman, a senior staff scientist at the Union of Concerned Scientists, has challenged specific cost-saving design choices made for both the AP1000 and ESBWR. Lyman is concerned about the strength of the steel containment vessel and the concrete shield building around the AP1000. The AP1000 containment vessel does not have sufficient safety margins, says Lyman.[2]
The first generation III reactors were built in Japan, while several others have been approved for construction in Europe. A Westinghouse AP1000 reactor is scheduled to become operational in Sanmen, China in 2013.[3]
Contents |
Generation III+ designs offer significant improvements in safety and economics over Generation III advanced reactor designs certified by the NRC in the 1990s.[6]