Study On Model Of VHTR And GFR Cores For Reactor Multiplication Calculation

STUDY ON MODEL OF VHTR AND GFR CORES FOR REACTOR MULTIPLICATION CALCULATION

Maman Mulyaman dan Zuhair
Pusat Teknologi Reaktor dan Keselamatan Nuklir (PTRKN), BATAN
Kawasan Puspiptek, Serpong, Tangerang 15310

ABSTRACT
STUDY ON MODEL OF VHTR AND GFR CORES FOR REACTOR MULTIPLICATION CALCULATION. VHTR and GFR are two candidates of Generation IV reactors which have received a lot of attention specifically to meet world energy needs in the future. These two reactors have different neutron spectrums, but use the same coolant material, namely helium. The outlet core temperatures of VHTR and GFR which are 1000oC and 850oC respectively enable them to produce hydrogen. In this paper, the cores of VHTR and GFR are modeled homogeneously, in which the heterogeneous cells are parsed into isotopic density and new materials consisting of weighted nuclides are formed. The model of cell shape is hexagon with 30 cm distance of flat to flat and 40 cm height. Because of incomplete specific temperature data for materials of nuclear fuel, cladding, and moderator/reflector, the calculation was done in room temperature and outlet core temperature. The calculation results using the Monte Carlo transport code MCNP5 and continuous energy nuclear data library ENDF/B-VI show that the GFR and VHTR have negative temperature effects with coefficient reactivity temperature of -5,1259E-5 Δk/k/oC and -5,5177E-5 Δk/k/oC, respectively. The value of keff VHTR, which is greater than 4.54% compared with those of GFR concludes that the presence of the role of graphite composition which dominates U-235 in VHTR and the effect of neutrons resonance absorption in U-238 which is significant in GFR.

Keywords: VHTR, GFR, reactor multiplication
Published : Proceeding "SEMINAR NASIONAL PENGEMBANGAN ENERGI NUKLIR II 2009", Jakarta, 25 Juni 2009.