Pressurized water reactor (PWR) burnup credit validation is
demonstrated using the benchmarks for quantifying fuel reactivity
decrements, published as Benchmarks for Quantifying Fuel Reactivity
Depletion Uncertainty, Electric Power Research Institute (EPRI)
report 1022909. This demonstration uses the depletion module
TRITON (Transport Rigor Implemented with Time-Dependent
Operation for Neutronic Depletion) available in the SCALE 6.1
(Standardized Computer Analyses for Licensing Evaluations) code

From 1998 to 2004, a series of critical experiments referred to as the fission product (FP) experimental program was performed at the Commissariat à l'Energie Atomique Valduc research facility. The experiments were designed by Institut de Radioprotection et de Sûreté Nucléaire (IRSN) and funded by AREVA NC and IRSN within the French program supporting development of a technical basis for burnup credit validation.

Analytical methods, described in this report, are used to
systematically determine experimental fuel sub-batch
reactivities as a function of burnup. Fuel sub-batch reactivities
are inferred using more than 600 in-core pressurized water
reactor (PWR) flux maps taken during 44 cycles of operation
at the Catawba and McGuire nuclear power plants. The
analytical methods systematically search for fuel sub-batch
reactivities that minimize differences between measured and
computed reaction rates, using Studsvik Scandpower’s

Progress toward developing a technical basis for a cost-effective burnup credit methodology for
spent nuclear fuel with initial U-235 enrichment up to 5% is presented. Present regulatory
practices provide as much burnup credit flexibility as can be currently expected. Further progress
is achievable by incorporating the negative reactivity effects of a subset of neutron-absorbing
fission product isotopes. Progress also depends on optimizing the procedure for establishing the

This report proposes and documents a computational benchmark for the estimation of the
additional reactivity margin available in spent nuclear fuel (SNF) from fission products and minor
actinides in a burnup-credit storage/transport environment, relative to SNF compositions
containing only the major actinides. The benchmark problem/configuration is a generic burnupcredit
cask designed to hold 68 boiling water reactor (BWR) spent nuclear fuel assemblies. The
purpose of this computational benchmark is to provide a reference configuration for the