Evaluation of RSG-GAS reactor in operation cycle No. 90

The operation of RSG-GAS reactor cycle 90, has conducted from December 26^th, 2015 to April 15^th, 2016. Based on this operation, data will be evaluated and used for the next reactor operation. The evaluation result will be improve for the core configuration, reactor operation, reactor utilization and experiences. Before the reactor is operated high power, control rod calibration should be performed to achieved the reactivity. The excess reactivity is 7.30 % and stuck rod reactivity is 4.11 % so as to ensure safe operation of the reactor. The reactor operation cycle No. 90 has achieved the power of 640, 0609 MWD is used for 114 sample irradiation and neutron beam services to PSTBM. Scram occurred 9 times due to failure of neutron detector JKT02 and JKT03 and problem of the reactor auxiliary systems are 36 times due to the failure of electrical systems, mechanical and instrumentation eg cooling tower fans PA02 AH001, AH003 and control rods, but the problem could be handled in the normal condition. The conclusion that the reactor operation cycle 90 was operation good condition, with the power of 15 MW and achieve a total energy of 640 MWD. (author)