Online monitoring of specific radionuclides in gaseous effluents

A feasibility study of automatic online monitoring of specific radionuclides in nuclear plant gaseous effluents is being conducted at the Georgia Tech Research Reactor (GTRR). An inpile loop experiment has been designed, built, and operated in the GTRR to simulate gaseous effluent mixtures anticipated for a variety of reactor situations. The gaseous fission product mixture may be altered by varying the flow rate of the helium sweep gas over the uranium-235 loaded microporous target, the neutron flux and temperature at the target, and the configuration of the cryogenic trapping system external to the reactor. The loop is used for experiments in remote monitoring of specific radionuclides to be experienced for normal, minor malfunction, and accident conditions at a nuclear plant. As a means of evaluating the practical aspects of automatic online monitoring, a remote monitoring system has been designed and built to measure nuclear and meteorological data at the GTRR, and to transmit the data to a central computer on either a routine "record keeping" or on an emergency-interrupt basis. The measurement system can be adjusted from the remote location to allow live time probing of conditions at the monitored location.