Page 228 - Dynamics and Control of Nuclear Reactors

16.4 BWR instrumentation 227

FIG. 16.15
In-core instrumentation in a typical PWR.
Courtesy of Westinghouse Electric Company ([6]).

The following are the important measurements in a typical BWR system:

• Local power range monitor (LPRM) detector signals (each LPRM string or tube
has 4 fission chambers).
• Average power range monitor (APRM) signals. An APRM signal is measured by
averaging about 20 LPRM detector signals from across the core.
• Reactor coolant flow rate. This is measured by venturi meters at the recirculation
pump discharge locations.
• Downcomer water level.
• Steam flow rate.
• Reactor pressure (steam pressure).
• Feed water flow rate.
• Feed water temperature.

A typical BWR has about 45 strings of in-core detectors (fission chambers).
Fig. 16.17 shows a BWR core map indicating detector locations. The in-core