Figure 2.8.5 An example of the basic configuration of the RCIC turbine

2. Pumps

The RCIC pumps are horizontal multistage pumps and sometimes double casing pumps are also used. Figure 2.8.6 shows a double casing pump configuration. The pump capacity is designed so that the reactor water level does not reach the ECCS actuation level when the reactor is isolated.

Specifically, this capacity can remove more heat than the decay heat at 15 minutes after shutdown.

2. Reactor Water Cleanup (cuw) System

1. System functions and configuration

The main objective of the CUW is to maintain reactor water qualities. Its functions are:

1. To remove corrosion products, fission products and soluble inorganic materials, etc. during plant normal operations and in reactor shutdown; and

2. To control the reactor water level while the feed water control system is not functioning

during reactor startup.

The system flow rate is about 1 to 7 % of the main feed water flow rate and, in most 1,100 MWe standard plants, it is about 2%. This flow rate is selected, taking into account such factors as keeping reactor water qualities, reducing radiation exposure and lowering costs.

Figure2.8.7 outlines the CUW system. The CUW system cools reactor water from the recirculation system suction line down to a temperature (49 °C) suitable for the filter demineralizer by using the regenerative and the non-regenerative heat exchangers located in the circulation pump suction line. The water is then pressurized by recirculation pumps. In the ABWR, reactor water is taken from the RHR suction lines for the shutdown cooling mode. After removing soluble and insoluble

Figure 2.8.6 Basic configuration of double casing RCIC pump

NSRA, Japan

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