A prototype device for testing of criticality monitors

Full text: Criticality monitor is an essential part of the radiation protection programme in a nuclear facility handling fissile materials. It is also important to evaluate the performance of the criticality monitors periodically. A prototype setup was made to meet the requirement of testing the criticality monitors, especially the response to sudden increase in the radiation field in a short time. A pneumatically operated system was employed to achieve this purpose. 137Cs source of 1.4 Ci strength was used in the experiment. All the monitors that have been tested responded satisfactorily. The details of the setup and the method of operation are discussed. The alarm limits set in the monitor have been discussed in the light of the guidelines specified in the ISO document 'Performance requirements and testing procedures for criticality detection and alarm systems'