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Topical Report on Actinide-Only Burnup Credit for PWR Spent Nuclear Fuel Packages
Topical Report on Actinide-Only Burnup Credit for PWR Spent Nuclear Fuel Packages
A methodology for performing and applying nuclear criticality safety calculations, for PWR spent nuclear fuel (SNF) packages with actinide-only burnup credit, is described. The changes in the U-234, U-235, U-236, U-238, Pu-238, Pu-239, Pu-240, Pu-241, Pu-242, and Am-241 concentration with burnup are used in burnup credit criticality analyses. No credit for fission product neutron absorbers is taken. The methodology consists of five major steps. (1) Validate a computer code system to calculate isotopic concentrations of SNF created during burnup in the reactor core and subsequent decay.
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
Modeling BWR Spent-Fuel Isotopics with SAS2H and CASMO-3
Modeling BWR Spent-Fuel Isotopics with SAS2H and CASMO-3
Effects of Integral Burnable Absorbers on PWR Spent Nuclear Fuel
Effects of Integral Burnable Absorbers on PWR Spent Nuclear Fuel
OECD/NEA Burnup Credit Criticality Benchmarks Phase IIIA: Criticality Calculations of BWR Spent Fuel Assemblies in Storage and Transport
OECD/NEA Burnup Credit Criticality Benchmarks Phase IIIA: Criticality Calculations of BWR Spent Fuel Assemblies in Storage and Transport
Standard Review Plan for Transportation Packages for MOX Spent Nuclear Fuel
Standard Review Plan for Transportation Packages for MOX Spent Nuclear Fuel
The NRC contracted with LLNL to compile this supplement to NUREG-1617 to incorporate additional
information specific to mixed uranium-plutonium oxide (MOX) fuel. This supplement provides details
on package review guidance resulting from significant differences between spent nuclear fuel from
irradiated LEU fuel and that from irradiated MOX fuel. The information presented is not to be
construed as having the force and effect of NRC regulations (except where regulations are cited), or as
Spent Fuel Burnup Credit in Casks: An NRC Perspective
Spent Fuel Burnup Credit in Casks: An NRC Perspective
Until now, the Nuclear Regulatory Commission's (NRC) approval of criticality safety evaluations for spent fuel in transport and storage casks has been based on analyzing the fuel as though it were fresh and without burnable poisons. The well-known nuclide composition of fresh fuel has provided a straightforward and bounding approach for showing that spent fuel systems will remain subcritical under normal and accident conditions. Burnup credit refers to the approval of criticality safety evaluations that consider the decrease in fuel reactivity caused by. irradiation in the reactor.
Selection of Reactor Criticals as Benchmarks for Spent Nuclear Fuels
Selection of Reactor Criticals as Benchmarks for Spent Nuclear Fuels
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
Nondestructive Assay of Nuclear Low-Enriched Uranium Spent Fuels for Burnup Credit Application
Nondestructive Assay of Nuclear Low-Enriched Uranium Spent Fuels for Burnup Credit Application
Criticality safety analysis devoted to spent-fuel storage and transportation has to be conservative in order to be sure no accident will ever happen. In the spent-fuel storage field, the assumption of freshness has been used to achieve the conservative aspect of criticality safety procedures. Nevertheless, after being irradiated in a reactor core, the fuel elements have obviously lost part of their original reactivity. The concept of taking into account this reactivity loss in criticality safety analysis is known as burnup credit.
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.
Key Issues Associated with Interim Storage of Used Nuclear Fuel
Key Issues Associated with Interim Storage of Used Nuclear Fuel
The issue of interim storage of used (spent)1 fuel is dependent on a number of key factors, some
of which are not known at this time but are the subject of this study. The first is whether or not
the Yucca Mountain Project continues or is cancelled such that it may be able to receive spent
fuel from existing and decommissioned nuclear power stations. The second is whether the United
States will pursue a policy of reprocessing and recycling nuclear fuel. The reprocessing and
Used Fuel Management System Interface Analyses
Used Fuel Management System Interface Analyses
Preliminary system-level analyses of the interfaces between at-reactor used fuel management, consolidated storage facilities, and disposal facilities, along with the development of supporting logistics simulation tools, have been initiated to provide the U.S. Department of Energy (DOE) and other stakeholders with information regarding the various alternatives for managing used nuclear fuel (UNF) generated by the current fleet of light water reactors operating in the United States.
Categorization of Used Nuclear Fuel Inventory in Support of a Comprehensive National Nuclear Fuel Cycle Strategy
Categorization of Used Nuclear Fuel Inventory in Support of a Comprehensive National Nuclear Fuel Cycle Strategy
A technical assessment of the current inventory [~70,150 metric tons of heavy metal (MTHM) as of
2011] of U.S.-discharged used nuclear fuel (UNF) has been performed to support decisions regarding fuel
cycle strategies and research, development and demonstration (RD&D) needs. The assessment considered
discharged UNF from commercial nuclear electricity generation and defense and research programs and
determined that the current UNF inventory can be divided into the following three categories:
Evaluation of a Spent Fuel Repository at Yucca Mountain, Nevada
Evaluation of a Spent Fuel Repository at Yucca Mountain, Nevada
In June 2008, the U.S. Department of Energy (DOE) submitted a license application to the U.S. Nuclear Regulatory Commission (NRC) for the construction of a geologic repository at Yucca Mountain, Nevada, for the disposal of spent nuclear fuel and high-level radioactive waste. The license application was accepted for formal NRC review in September 2008. Throughout the more than 20-year history of the Yucca Mountain project, EPRI has performed independent assessments of key technical and scientific issues to facilitate an understanding of overall repository performance.
Transportation of Commercial Spent Nuclear Fuel Regulatory Issues Resolution
Transportation of Commercial Spent Nuclear Fuel Regulatory Issues Resolution
The U.S. industry’s limited efforts at licensing transportation packages characterized as “highcapacity,”
or containing “high-burnup” (>45 GWd/MTU) commercial spent nuclear fuel
(CSNF), or both, have not been successful considering existing spent-fuel inventories that will
have to be eventually transported. A holistic framework is proposed for resolving several CSNF
transportation issues. The framework considers transportation risks, spent-fuel and cask-design
Industry Spent Fuel Storage Handbook
Industry Spent Fuel Storage Handbook
The Industry Spent Fuel Storage Handbook (“the Handbook”) addresses the relevant aspects of at-reactor spent (or used) nuclear fuel (SNF) storage in the United States. With the prospect of SNF being stored at reactor sites for the foreseeable future, it is expected that all U.S. nuclear power plants will have to implement at-reactor dry storage by 2025 or shortly thereafter. The Handbook provides a broad overview of recent developments for storing SNF at U.S. reactor sites, focusing primarily on at-reactor dry storage of SNF.
Cost Estimate for an Away-From-Reactor Generic Interim Storage Facility (GISF) for Spent Nuclear Fuel
Cost Estimate for an Away-From-Reactor Generic Interim Storage Facility (GISF) for Spent Nuclear Fuel
As nuclear power plants began to run out of storage capacity in spent nuclear fuel (SNF) storage pools, many nuclear operating companies added higher density pool storage racks to increase pool capacity. Most nuclear power plant storage pools have been re-racked one or more times. As many spent fuel storage pools were re-racked to the maximum extent possible, nuclear operating companies began to employ interim dry storage technologies to store SNF in certified casks and canister-based systems outside of the storage pool in independent spent fuel storage installations (ISFSIs).
EPRI Review of Geologic Disposal for Used Fuel and High-Level Radioactive Waste: Volume III --Review of National Repository Programs
EPRI Review of Geologic Disposal for Used Fuel and High-Level Radioactive Waste: Volume III --Review of National Repository Programs
The effective termination of the Yucca Mountain program by the U.S. Administration in 2009
has left the U.S. program for management of used fuel and high level radioactive waste (HLW)
in a state of uncertainty. In concert with this major policy reset and in response to the resulting
policy vacuum, the President directed the Energy Secretary to establish the Blue Ribbon
Commission on America’s Nuclear Future (BRC) “…to conduct a comprehensive review of
policies for managing the back end of the nuclear fuel cycle and to provide recommendations for