PEMODELAN TERAS UNTUK ANALISIS PERHITUNGAN KONSTANTA MULTIPLIKASI REAKTOR HTR-PROTEUS

Abstract

PTRKN as a working unit in BATAN whose main duties and functions are related to reactor technology and nuclear safety, consern attention to pebble bed reactor concept. In this paper modeling of HTR-PROTEUS pebble bed reactor was done using Monte Carlo transport code MCNP5. The TRISO coated fuel particle is modeled in detailed and exact manner where random distributions of these particles in fuel pebble is approximated by using regular array of SC lattice with packing fraction of 5.76% without exclusive zone. Pebble bed core modeling was approximated by utilizing regular lattice of balls that are arranged as BCC lattice based on repeated cell generated from a numerous unit cell. The MCNP5 calculation results showed that excellent agreement with the experiment, although the HTRPROTEUS core predicted more reactive than the measurement, especially in cores 4.2 and 4.3. ENDF/B-VI library indicates consistency with the most accurate keff estimation compared to ENDF/B-V library, mainly ENDF/B-VI (66c). The deviation of calculated keff estimation with experiment is attributed to the consequence of specified graphite reflector composition. The comparison conducted shows that MCNP5 produces HTR-PROTEUS core keff is more precise compared to the results of MCNP4B and MCNP-BALL. These results concluded that the success of this modeling methodology justifies MCNP5 application for other pebble bed reactor analysis.