Validation of a subgroup method for pressurized water reactor fuel assembly models

A. Canbakan (1) , A. Hebert (1) , J.-F. Vidal (2)

1 EPM - École Polytechnique de Montréal
2 CEA-DES (ex-DEN) - CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire)

We are investigating the accuracy of a self-shielding model based on a subgroup method for pressurized water reactor (PWR) fuel assembly models. Until now, APOLLO2 lattice code was using the Sanchez-Coste method based on an $equivalence\ in\ dilution$ with a 281-group Santamarina-Hfaiedh energy mesh (SHEM). Here, we validate a subgroup approach with an improved 361-energy group SHEMat burnup 0 and with isotopic depletion. The aim is to show this new self-shielding technique is more precise than the current one and leads to simpler production computational schemes by avoiding complicated correction algorithms for the mutual resonant self-shielding effects. Compared to a Monte Carlo reference case, the new approach leads to encouraging results in almost every cases. This subgroup technique is proposed as a short-term replacement for the Sanchez-Coste method used in production computational schemes dedicated to the production of multi-parameter cross-section reactor databases.

Keywords: Reactor physics; Self-shielding; Lattice scheme; APOLLO2

Domains: Nuclear Experiment [nucl-ex]; Nuclear Theory [nucl-th]

A. Canbakan, A. Hebert, J.-F. Vidal. Validation of a subgroup method for pressurized water reactor fuel assembly models. ANS MC2015 - Joint International Conference on Mathematics and Computation (M&C), Supercomputing in Nuclear Applications (SNA) and the Monte Carlo Method, Apr 2015, Nashville, United States. ⟨cea-02489479⟩