The Nuclear Regulatory Commission approved a rule to certify GE-Hitachi Nuclear Energy’s Economic Simplified Boiling-Water Reactor (ESBWR) design for use to generate electric power in the United States.

The NRC supplemented its draft certification rule in May 2014 to account for changes in analysis of the nuclear power plant design’s steam dryer, which prevents excess moisture from damaging a nuclear power plant’s electricity-generating turbine. NRC reviewers asked for additional steam dryer information from GE-Hitachi between 2011 and 2013. The staff’s review of that information led to the supplement, which also incorporated several dozen reference documents as requirements in the draft certification rule.

GE-Hitachi Nuclear Energy submitted its application for ESBWR certification on Aug. 24, 2005. The ESBWR is a 1,594 MW (electric), natural circulation reactor. The design includes passive safety features that would cool the reactor after an accident without the need for human intervention. These passive features include enhanced natural circulation via a taller reactor vessel, a shorter core and improved water flow through the vessel; an isolation condenser system to control water levels and remove decay heat while the reactor is pressurized, and; a gravity-driven cooling system to maintain water levels when the reactor pressure has dropped.

The NRC has certified four other standard reactor designs: the Advanced Boiling Water Reactor, System 80+, AP600 and AP1000.