Hammam Oktajianto
Physics Department, Faculty of Sciences and Mathematics, Diponegoro University
Articles
2
Documents
Modelling of HTR (High Temperature Reactor) Pebble-Bed 10 MW to Determine Criticality as A Variations of Enrichment and Radius of the Fuel (Kernel) With the Monte Carlo Code MCNP4C

International Journal of Science and Engineering Vol 8, No 1 (2015)
Publisher : Chemical Engineering Diponegoro University

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Abstract

Gas-cooled nuclear reactor is a Generation IV reactor which has been receiving significant attention due to many desired characteristics such as inherent safety, modularity, relatively low cost, short construction period, and easy financing. High temperature reactor (HTR) pebble-bed as one of type of gas-cooled reactor concept is getting attention. In HTR pebble-bed design, radius and enrichment of the fuel kernel are the key parameter that can be chosen freely to determine the desired value of criticality. This paper models HTR pebble-bed 10 MW and determines an effective of enrichment and radius of the fuel (Kernel) to get criticality value of reactor. The TRISO particle coated fuel particle which was modelled explicitly and distributed in the fuelled region of the fuel pebbles using a Simple-Cubic (SC) lattice. The pebble-bed balls and moderator balls distributed in the core zone using a Body-Centred Cubic lattice with assumption of a fresh fuel by the fuel enrichment was 7-17% at 1% range and the size of the fuel radius was 175-300 µm at 25 µm ranges. The geometrical model of the full reactor is obtained by using lattice and universe facilities provided by MCNP4C. The details of model are discussed with necessary simplifications. Criticality calculations were conducted by Monte Carlo transport code MCNP4C and continuous energy nuclear data library ENDF/B-VI. From calculation results can be concluded that an effective of enrichment and radius of fuel (Kernel) to achieve a critical condition was the enrichment of 15-17% at a radius of 200 µm, the enrichment of 13-17% at a radius of 225 µm, the enrichments of 12-15% at radius of 250 µm, the enrichments of 11-14% at a radius of 275 µm and the enrichment of 10-13% at a radius of 300 µm, so that the effective of enrichments and radii of fuel (Kernel) can be considered in the HTR 10 MW. Keywords—MCNP4C, HTR, enrichment, radius, criticality 

Gamma Spectroscopy Response Analysis of Bismuth Germanium Oxide (BGO) and NaI (Tl) Detector to Determine the Detector Efficiency using the Monte Carlo MCNPX Method

JURNAL SAINS DAN MATEMATIKA Volume 23 Issue 2 Year 2015
Publisher : JURNAL SAINS DAN MATEMATIKA

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Abstract

Simulation of Gamma spectroscopy with Bismuth Germinate Oxide (BGO) and NaI(Tl) detectors has been done using Monte Carlo method in MCNPX computer program. Simulation was conducted by modelling detector scintillator geometry, model of radiation source which was Cobalt-60 and pulse count model. BGO and NaI(Tl) had a diameter of 3 inch and thickness of 3 inch and closed by Aluminium with 0.05 cm thickness. Extended radiation source of Cobalt-60 was in radius of 0.15 cm which was put in front of detector surface with distance of 0.001 cm, 2 cm, 4 cm, and 12 cm. The simulation results showed that the less radiation count with increasing distance of the radiation source which was put in front of detector. Reduce of the radiation count lead to decrease efficiency in each increase of radiation source distance. The detector efficiency to count gamma ray radiation of BGO detectors was better than NaI(Tl) detector. The maximum efficiency of both detectors was occurred at distance of 0.001 cm in front of detector. These results also showed that MCNPX was able to agreeably simulate detector process to determine spectroscopy Gamma response.