Optical gamma thermometer

摘要

An optical gamma thermometer (30) includes a metal mass (34) having a temperature proportional to a gamma flux within a core (15) of a nuclear reactor, and an optical fiber cable (32) for measuring the temperature of the heated metal mass. The temperature of the heated mass (34) may be measured by using one or more fiber grating structures (42) and/or by using scattering techniques, such as Raman, Brillouin, and the like. The optical gamma thermometer (30) may be used in conjunction with a conventional reactor heat balance to calibrate the local power range monitors (M) over their useful in-service life. The optical gamma thermometer (30) occupies much less space within the in-core instrument tube (24) and costs much less than the conventional gamma thermometer (T).