Continuous measurement of iodine concentration in the primary coolant of a nuclear power plant

The conventional method for monitoring the iodine level in the reactor coolant has been to manually take grab samples of the coolant several times a week. If the iodine levels are elevated or increasing, more frequent sampling is usually conducted. There has been a great demand for a reliable on-line automated iodine concentration monitoring system. Until recently, however, some technical difficulties associated with a conventional automated Ge detector and signal processing circuit have limited the application of such a system to the monitoring of high iodine concentrations. The conventional on-line monitoring system cannot reliably detect lower concentrations. Recently technical advances in these areas have made it possible to overcome these limitations.