Design of the advanced accumulator for the pressurized water reactor

With the increased requirement for nuclear power generation as an effective countermeasure against global warming, Mitsubishi has developed the advanced pressurized water reactor (APWR) by adopting a new component of the emergency core cooling system (ECCS), a new instrumentation and control system, and other newfound improvements. The ECCS introduces a new passive component called the advanced accumulator which integrates both functions of the conventional accumulator and the low-pressure pump without any moving parts. The advanced accumulator uses a new fluidics device that automatically regulates flow rates of injected water in case of a loss of coolant accident (LOCA). This fluidics device is referred to as a flow damper. This paper describes the design method of the flow damper and the standpipe.

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► Mitsubishi has developed the APWR by adopting a new component of the ECCS.
► ECCS introduces a new passive component “flow damper” in advanced accumulator.
► ACC automatically changeovers flow rate without any moving parts.
► Standpipe detects water level and a strong vortex in the chamber reduces flow rate.
► This paper describes the design method of the flow damper and the standpipe in ACC.