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PCA Benchmark Analysis with ADVANTG3.0.1. and MCNP6.1.1b Codes

Mario Matijević, orcid.org/0000-0001-9775-5773 ; University of Zagreb, Faculty of Electrical Engineering and Computing Unska 3, 10000 Zagreb, Croatia
Dubravko Pevec, ; University of Zagreb, Faculty of Electrical Engineering and Computing Unska 3, 10000 Zagreb, Croatia
Krešimir Trontl ; University of Zagreb, Faculty of Electrical Engineering and Computing Unska 3, 10000 Zagreb, Croatia
Bojan Petrović orcid.org/0000-0001-9217-7863 ; Georgia Institute of Technology, Nuclear and Radiological Engineering 770 State St., Atlanta, GA 30332-0745, USA

Sažetak

The Pool Critical Assembly Pressure Vessel (PCA) benchmark is a well known benchmark in
the reactor shielding community which is described in the Shielding Integral Benchmark Archive
and Database (SINBAD). It is based on the experiments performed at the PCA facility in the Oak
Ridge National Laboratory (ORNL) and it can be used for the qualification of the pressure vessel
fluence calculational methodology. The measured quantities to be compared against the calculated
values are the equivalent fission fluxes at several experimental access tubes (A1 to A8) in front,
behind, and inside the pressure-vessel wall simulator. This benchmark is particularly suitable to test
the capabilities of the shielding calculational methodology and cross-section libraries to predict invessel
flux gradients because only a few approximations are necessary in the overall analysis. This
benchmark was analyzed using a modern hybrid stochastic-deterministic shielding methodology
with ADVANTG3.0.1 and MCNP6.1.1b codes. ADVANTG3.0.1 is an automated tool for
generating variance reduction (VR) parameters for Monte Carlo (MC) calculations with
MCNP5v1.60 code (and higher versions). It is based on the multigroup, discrete ordinates solver
Denovo, used for approximating the forward-adjoint transport fluxes to construct VR parameters for
the final MC simulation. The VR parameters in form of the weight windows and the source biasing
cards can be directly used with unmodified MCNP input. The underlining CADIS methodology in
Denovo code was initially developed for biasing local MC results, such as point detector or a
limited region detector. The FW-CADIS extension was developed for biasing MC results globally
over a mesh tallies or multiple point/region detectors. Both CADIS and FW-CADIS are based on
the concept of the neutron importance function, which is a solution of the adjoint Boltzmann
transport equation. The equivalent fission fluxes calculated with MCNP are based on several highenergy
threshold reactions from international dosimetry libraries IRDF-2002 and IRDFF-2014,
distributed by the IAEA Nuclear Data Section. The obtained results show a good agreement with
referenced PCA measurements. Visualization of the deterministic solution in 3D was done using the
VisIt code from the Lawrence Livermore National Laboratory (LLNL).

Ključne riječi

PCA benchmark, shielding, pressure vessel, Monte Carlo, variance reduction

Hrčak ID:

247099

URI

https://hrcak.srce.hr/247099

Datum izdavanja:

28.10.2019.

Posjeta: 772 *