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Actinide-Only Burnup Credit for Pressurized Water Reactor Spent Nuclear Fuel - I: Methodology Overview
Actinide-Only Burnup Credit for Pressurized Water Reactor Spent Nuclear Fuel - I: Methodology Overview
A conservative methodology is presented that would allow taking credit for burnup in the criticality safety analysis of spent nuclear fuel (SNF) packages. The method is based on the assumption that the isotopic concentration in the SNF and cross sections of each isotope for which credit is taken must be supported by validation experiments. The method allows credit for the changes in the 234U, 235U, 236U, 238U, 238Pu, 239Pu, 240Pu, 241Pu, 242Pu, and 241Am concentration with burnup. No credit for fission product neutron absorbers is taken. The methodology consists of five major steps:
Actinide-Only Burnup Credit for Pressurized Water Reactor Spent Nuclear Fuel - III: Bounding Treatment of Spatial Burnup Distributions
Actinide-Only Burnup Credit for Pressurized Water Reactor Spent Nuclear Fuel - III: Bounding Treatment of Spatial Burnup Distributions
A flat, uniform axial burnup assumption, preferred for its computational simplicity, does not always conservatively estimate the pressurized water reactor spent-fuel-cask multiplication factors. Rather, the reactivity effect of the significantly underburned fuel ends, usually referred to as the "end effect," can be properly treated by explicit modeling of the axial burnup distribution based on limiting axial burnup profiles.
Actinide-Only Burnup Credit for Pressurized Water Reactor Spent Nuclear Fuel - II: Validation
Actinide-Only Burnup Credit for Pressurized Water Reactor Spent Nuclear Fuel - II: Validation
The calculation of isotopic concentrations in spent nuclear fuel (SNF) assemblies and the subcritical multiplication factor of SNF packages are two of the essential requirements of the actinide-only burnup credit methodology. To justify the accuracy of the computed values, the code systems used to perform the calculations must be validated. Here, the techniques used for actinide-only burnup credit isotopic and criticality validation are presented and demonstrated.
A Critical Review of the Practice of Equating the Reactivity of Spent Fuel to Fresh Fuel in Burnup Credit Criticality Safety Analyses for PWR Spent Fuel Pool Storage
A Critical Review of the Practice of Equating the Reactivity of Spent Fuel to Fresh Fuel in Burnup Credit Criticality Safety Analyses for PWR Spent Fuel Pool Storage
This research examines the practice of equating the reactivity of spent fuel to that of fresh fuel for the purpose of performing burnup credit criticality safety analyses for PWR spent fuel pool (SFP) storage conditions. The investigation consists of comparing kf estimates based on reactivity "equivalent" fresh fuel enrichment (REFFE) to kl estimates using the actual spent fuel isotopics.
Use of Reactor-Follow Data to Determine Biases and Uncertainties for PWR spent Nuclear Fuel
Use of Reactor-Follow Data to Determine Biases and Uncertainties for PWR spent Nuclear Fuel
Effects of Integral Burnable Absorbers on PWR Spent Nuclear Fuel
Effects of Integral Burnable Absorbers on PWR Spent Nuclear Fuel
An Empirical Approach to Bounding the Axial Reactivity Effects of PWR Spent Nuclear Fuel
An Empirical Approach to Bounding the Axial Reactivity Effects of PWR Spent Nuclear Fuel
One of the significant issues yet to be resolved for using
burnup credit ~BUC! for spent nuclear fuel ~SNF! is establishing
a set of depletion parameters that produce an adequately conservative
representation of the fuel’s isotopic inventory. Depletion
parameters ~such as local power, fuel temperature, moderator temperature,
burnable poison rod history, and soluble boron concentration!
affect the isotopic inventory of fuel that is depleted in a
pressurized water reactor ~PWR!. However, obtaining the detailed
Investigation of the Effect of Fixed Absorbers on the Reactivity of PWR Spent Nuclear Fuel for Burnup Credit
Investigation of the Effect of Fixed Absorbers on the Reactivity of PWR Spent Nuclear Fuel for Burnup Credit
The effect of fixed absorbers on the reactivity of pressurized water reactor (PWR) spent nuclear fuel (SNF) in support of burnup-credit criticality safety analyses is examined. A fuel assembly burned in conjunction with fixed absorbers may have a higher reactivity for a given burnup than an assembly that has not used fixed absorbers. As a result, guidance on burnup credit, issued by the U.S. Nuclear Regulatory Commission's Spent Fuel Project Office, recommends restricting the use of burnup credit to assemblies that have not used burnable absorbers.
Phenomena and Parameters Important to Burnup Credit
Phenomena and Parameters Important to Burnup Credit
Since the mid-1980s, a significant number of studies have been directed at understanding the phenomena and
parameters important to implementation of burnup credit in out-of-reactor applications involving pressurizedwater-
reactor (PWR) spent fuel. The efforts directed at burnup credit involving boiling-water-reactor (BWR)
spent fuel have been more limited. This paper reviews the knowledge and experience gained from work
performed in the United States and other countries in the study of burnup credit. Relevant physics and analysis
Axial Burnup Profile Database for Pressurized Water Reactors
Axial Burnup Profile Database for Pressurized Water Reactors
The data were obtained directly from utilities whose reactors represent the range of commercial PWR fuel lattices. The work was performed by Yankee Atomic Electric for Sandia National Laboratory. All axial burnup profiles were calculated from 3-D depletion analyses of the core configuration. The organizations and utilities providing axial burnup profiles for the database used different model codes for the 3D-depletion calculations. The model codes used were: SIMULATE-3, NEMO, ANC, and PRESTO-II. Cross-section inputs describing the assemblies are derived from assembly lattice calculations.
SCALE-4 Analysis of Pressurized Water REactor Critical Configurations: Volume 5 - North Anna Unit 1 Cycle 5
SCALE-4 Analysis of Pressurized Water REactor Critical Configurations: Volume 5 - North Anna Unit 1 Cycle 5
The requirements of ANSI/ANS 8.1 specify that calculational methods for away-from-reactor
(AFR) criticality safety analyses be validated against experimental measurements. If credit for the
negative reactivity of the depleted (or spent) fuel isotopics is desired, it is necessary to benchmark
computational methods against spent fuel critical configurations. This report summarizes a portion
of the ongoing effort to benchmark AFR criticality analysis methods using selected critical
configurations from commercial pressurized-water reactors (PWR).
Range of Neutronic Parameters Calculation File
Range of Neutronic Parameters Calculation File
The purpose of this engineering calculation is to document the benchmark range, over a variety of parameters, for the validation of the criticality calculations supporting the Monitored Geologic Repository (MGR). This engineering calculation accomplishes this by characterizing the Laboratory Critical Experiments (LCE) and the Pressurized Water Reactor (PWR) Commercial Reactor Criticals (CRC), and summarizing the significant parameters. This engineering calculation supports the Disposal Criticality Analysis Methodology program.
Burn-up Credit Criticality Safety Benchmark - Phase VII, UO2 Fuel: Study of Spent Fuel Compositions for Long-term Disposal
Burn-up Credit Criticality Safety Benchmark - Phase VII, UO2 Fuel: Study of Spent Fuel Compositions for Long-term Disposal
Radiation Effects of Isotopic Uncertainty for Burnup Credit Validation
Radiation Effects of Isotopic Uncertainty for Burnup Credit Validation
The objective of this calculation is to provide the uncertainty term for fission product and minor actinides which contributes to the determination of the critical limit for burnup credit calculations. The scope of this calculation covers PWR and BWR spent nuclear fuel. This activity supports the Criticality Department's validation of burnup credit. The intended use of these results is in future Criticality Department calculations and analyses.