Development of Fugen Gate Monitor

Fuel assemblies in the reactor core of Fugen can not be verified directly due to the unique reactor structure so the IAEA inspection goal had not been attained since reactor began operation. To obtain the inspection goal, Japan and IAEA had established the safeguards approach. The discussion with the IAEA led to a dual C/S (by a surveillance camera) and a radiation monitor. However, for the development of the monitor, many technical problems were identified and a long development time was anticipated. PNC and LANL developed the Fugen Gate Monitor (FUGM) under the PNC/DOE cooperation agreement. FUGM detectors contain ion chambers, He-3 tubes and fission chambers. The FUGM can verify the number of fuel transfers, direction of the transfers and type of fuel assembly. FUGM was installed in November 1995, and it has been used for the routine IAEA inspection since January 1996 so that requirement of the inspection goal attainment can be achieved. (author)