Studies on calculation models of ASTRA critical facility benchmark using OpenMC

Abstract In this paper we report validation studies of the Monte Carlo code OpenMC by the ASTRA critical facility benchmark. A high-fidelity reactor model is built using the regular lattice coated fuel particle and the body centered cube pebble spheres representations. Two nuclear data libraries, ENDFB-7.0 and ENDFB-7.1 are considered to investigate the validity of nuclear cross section libraries. In addition, three homogenization models namely the core-hom model, the ref-hom model and the CR-hom model are built to provide references for analyzing the spatial approximations employed in deterministic codes. The core-hom model equivalents the octahedral core by a cylindrical zone, the ref-hom model homogenizes the side reflector into a cylindrical region, and the CR-hom model approximates the tube-cluster-shaped control rods (CR) into a concentric annulus. Results demonstrate that ENDFB-7.1 library outperforms ENDFB-7.0 by predicting criticality more accurately. The difference between the two libraries is 1224 pcm for the criticality calculation at the experimental pebble bed height (268.9 cm). With ENDFB-7.1 the high-fidelity model well-predicts the experimental data by 620 pcm error in keff and less than 6.5% difference in CR worth. The homogenization of the reflector brings about a pronounced error of 1143 pcm. In contrast, the core-hom model causes a comparably minor discrepancy of 241 pcm to the keff, while its influence on the CR worth appears most significant for CRs located close to the core zone. The CR-hom model yields a −2.1% maximum accuracy loss in CR worth from the high-fidelity model. After all, both the high-fidelity model and the core-hom model succeed in capturing the CR interference effect and in predicting the trend of CR differential worth. This work is not only meaningful for demonstrating the validity of OpenMC, but also useful to investigate the numerical accuracy of codes used in emerging work related to PBHTGR.

[1]  Zukile Zibi,et al.  Benchmarking of MCNP modelling of HTR cores against experimental data from the astra critical facility , 2010 .

[2]  David W. Nigg,et al.  CYNOD: A Neutronics Code for Pebble Bed Modular Reactor Coupled Transient Analysis , 2008 .

[3]  Yishu Qiu,et al.  RMC – A Monte Carlo code for reactor core analysis , 2015 .

[4]  Guoming Liu,et al.  A comprehensive evaluation of the RPT method on FCM fuel in light water reactor , 2020 .

[5]  Julian Robert Lebenhaft.  MCNP4B Modeling of Pebble-Bed Reactors , 2001 .

[6]  Richard Sanchez,et al.  Renormalized treatment of the double heterogeneity with the method of characteristics , 2004 .

[7]  Benoit Forget,et al.  The OpenMC Monte Carlo particle transport code , 2012 .

[8]  Kan Wang,et al.  Improved adaptive variance reduction algorithm based on RMC code for deep penetration problems , 2020 .

[9]  G. C. Pomraning,et al.  A statistical analysis of the double heterogeneity problem , 1991 .

[10]  Üner Çolak,et al.  Monte Carlo Criticality Calculations for a Pebble Bed Reactor with MCNP , 2005 .

[11]  Danas Ridikas,et al.  Modelling of HTRs with Monte Carlo: from a homogeneous to an exact heterogeneous core with microparticles , 2003 .

[13]  Ding She,et al.  XPZ: Development of a lattice code for HTR , 2016 .

[14]  Felix C. Difilippo.  Monte Carlo Calculations of Pebble Bed Benchmark Configurations of the PROTEUS Facility , 2003 .

[15]  Deokjung Lee,et al.  MCS – A Monte Carlo particle transport code for large-scale power reactor analysis , 2020 .

[16]  Very Richardina,et al.  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 , 2015 .

[17]  Forrest B. Brown,et al.  Stochastic geometry capability in MCNP5 for the analysis of particle fuel , 2004 .

[18]  Shi Dunfu,et al.  JMCT Monte Carlo analysis of BEAVRS benchmark: hot zero power results , 2016 .

[19]  Amin Abedi,et al.  Neutronic simulation of a pebble bed reactor considering its double heterogeneous nature , 2012 .

[21]  Lei Shi,et al.  PANGU code for pebble-bed HTGR reactor physics and fuel cycle simulations , 2019, Annals of Nuclear Energy.

[22]  Huaqing Zheng,et al.  CAD-based Monte Carlo Program for Integrated Simulation of Nuclear System SuperMC , 2014, ICS 2014.

[23]  Paul K. Romano,et al.  OpenMC: A State-of-the-Art Monte Carlo Code for Research and Development , 2014, ICS 2014.

[24]  Jan Leen Kloosterman,et al.  Analytical Calculation of the Average Dancoff Factor for a Fuel Kernel in a Pebble Bed High-Temperature Reactor , 1999 .