A New Instrument for the Confirmation of Declared Power Histories of Central Station Nuclear Power Plants

An operationally simple, portable, microprocessorbased, unattended reactor power monitor was developed for International Atomic Energy Agency inspector use in confirming operator records of the power history of nuclear power plants. The monitor is based on the principle that the leakage neutron flux outside the biological shield is proportional to the thermal power level. The leakage flux is detected and compared with the leakage flux from the same reactor for a confirmed calibration period. Several output options are available, and a record of more than three months of hourly measurements of the thermal power of the plant can be obtained. The monitor has battery backup power for interruptions of host power of duration up to 18 hours.