Power and neutron flux distribution analysis in the RSG-GAS reactor :preliminary study to identify the reactor readiness as Power Ramp Test Facility (PRTF)

Abstract

PRTF RSG-GAS is an irradiation facility that used especially for testing fuel pin element of nuclear power plant reactor. Before, during and after the testing, reactor shall remain in critical and steady state condition. In this research, we determine the PRTF readiness before testing. Pre-experimental analysis was performed using Monte Carlo method by MCNP- 6 software. Keff value of RSG-GAS obtained in this study is 1,10234±0.00011 at power operation (15 MW). The total power was obtained 13.6 MW with difference of 9.3% to the actual operating power at RSG GAS. The maximum power released by one fuel and the average rod power at operating power reach 2.4 × 10−2 MW and 9.5 × 10−3MW. The total neutron flux of PRTF at J7 and K7 grid position respectively are 0.64 × 1014 n.cm−2 s−1(70.80% thermal neutron flux and 29.20% fast neutron flux); and 0.26 × 1014 n.cm−2 s−1(84.89% thermal neutron flux and 15.11% fast neutron flux). Both testing location show that neutron profile dominated by thermal neutron. This condition enables to use irradiated fuel elements. However, if the neutron flux present in PRTF is generate to excessive fission reactions, it will adversely affect to the fuel element which testing and the reactor. Therefore, the existence of thermal neutrons and their changes when the irradiation proccess take place becomes an interesting topic to do.