POWER-PLANT MONITORING
Through keeping track of the radiation level at various points in the reactor system, any abnormalities in operation can be quickly detected and corrected.
A leak in the heat exchangers, for example, would show up on a radiation monitor located in the blowdown line from each of the heat exchangers.
The intermediate cooling system, which includes cooling water from the primary pumps, shield water cooler, containment air cooler, and other components not directly in the primary loop, is monitored at five locations. Leakage of primary loop water into the secondary water is possible only from the pumps and letdown coolers, because of differences in pressure. Consequently, radiation monitors are located downstream from the letdown coolers and in each of the return lines from the pump cooling coils.
The demineralizers are also monitored. When the resin bed is functioning, the flow downstream (effluent) will have negligible radioactivity. Consequently, a monitor signal at this point will indicate when to switch to a new demineralizer. The monitor in the influent (water entering the demineralizer) measures the activity level in the primary loop.
The fission product monitor keeps track of fission product activity in the primary (reactor) system. The monitor consists of a cation and anion column, an amplifier, and an indicating system. This monitor is located in the primary coolant flow system.