Three-dimensional (X,Y,Z) deterministic analysis of the PCA-Replica neutron shielding benchmark experiment using the TORT-3.2 code and group cross section libraries for LWR shielding and pressure vessel dosimetry

The PCA-Replica 12/13 (H₂O/Fe) neutron shielding benchmark experiment was analysed using the ORNL TORT-3.2 3D SN code. PCA-Replica, specifically conceived to test the accuracy of nuclear data and transport codes employed in LWR shielding and radiation damage calculations, reproduces a PWR ex-core radial geometry with alternate layers of water and steel including a PWR pressure vessel simulator. Three broad-group coupled neutron/photon working cross section libraries in FIDO-ANISN format with the same energy group structure (47 n + 20 γ) and based on different nuclear data were alternatively used: the ENEA BUGJEFF311.BOLIB (JEFF-3.1.1) and BUGENDF70.BOLIB (ENDF/B-VII.0) libraries and the ORNL BUGLE-96 (ENDF/BVI.3) library. Dosimeter cross sections derived from the IAEA IRDF-2002 dosimetry file were employed. The calculated reaction rates for the Rh¹⁰³(n,n')Rh^{103 m}, In¹¹⁵(n,n')In^115m and S³²(n,p)P³² threshold activation dosimeters and the calculated neutron spectra are compared with the corresponding experimental results. The deviations of the dosimetric results from the corresponding experimental ones are within the desired ±10-15% target accuracy. Given that the total experimental uncertainty ranges up to approximately 5%, then the computational results presented in this paper exhibit very good statistical consistency with the corresponding measurements