The purpose of this calculation report is to document the comparison to measurement of the isotopic concentrations for pressurized water reactor (PWR) spent nuclear fuel determined with the Standardized Computer Analysis for Licensing Evaluation (SCALE) 5.1 (Ref. 1) depletion calculation method. Specifically, the depletion computer code and the cross-section library being evaluated are the two-dimensional (2-D) transport and depletion module, TRITON/NEWT,2, 3 and the 44GROUPNDF5 (Ref. 4) cross-section library, respectively, in the SCALE 5.1 code system.
This calculation report was developed in support of licensing activities for the proposed repository at Yucca Mountain, Nevada, and the development of the report is consistent with Test Plan for: Isotopic Validation for Postclosure Criticality of Commercial Spent Nuclear Fuel.5 The calculation report describes a comprehensive evaluation of radiochemical measurement, assembly design, and irradiation history data for 118 PWR spent fuel samples obtained from low-, moderate-, and high-burnup spent fuel assemblies from nine PWRs: Trino Vercellese, Kernkraftwerk Obrigheim (KWO), Turkey Point Unit 3, H. B. Robinson Unit 2, Calvert Cliffs Unit 1, Three Mile Island (TMI) Unit 1, Takahama Unit 3, Gösgen, and GKN II. The initial fuel enrichments and burnup values for the samples considered vary from 2.453 to 4.657 wt % 235U and from 7.2 to 70.4 GWd/MTU, respectively. The majority of the spent fuel samples were obtained from UO2 rods in assemblies with no exposure to either burnable poison rods or control rods. However, the evaluated spent fuel samples also include samples from UO2 assemblies containing burnable poison rods and samples from gadolinia rods. The report also describes the TRITON/NEWT models developed and provides the values obtained for the ratio of experimental-to-calculated (E/C) isotopic concentrations.