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An Extension of the Validation of SCALE (SAS2H) Isotopic Predictions of PWR Spent Fuel
An Extension of the Validation of SCALE (SAS2H) Isotopic Predictions of PWR Spent Fuel
Isotopic characterization of spent fuel via depletion and decay calculations is necessary for
determination of source terms for subsequent system analyses involving heat transfer, radiation
shielding, isotopic migration, etc. Unlike fresh fuel assumptions typically employed in the criticality
safety analysis of spent fuel configurations, burnup credit applications also rely on depletion and
decay calculations to predict the isotopic composition of spent fuel. These isotopics are used in
Translation of Technical Development on Burn-Up Credit for Spent LWR Fuels
Translation of Technical Development on Burn-Up Credit for Spent LWR Fuels
Technical development on burn-up credit for spent LWR fuels had been performed at JAERI since
1990 under the contract with Science and Technology Agency of Japan entitled ‘Technical Development on
Criticality Safety Management for Spent LWR Fuels.’ Main purposes of this work are to obtain the
experimental data on criticality properties and isotopic compositions of spent LWR fuels and to verify burnup
and criticality calculation codes. In this work three major experiments of exponential experiments for
Confidence in the Long-term Safety of Deep Geological Repositories
Confidence in the Long-term Safety of Deep Geological Repositories
Confidence in the long-term safety of deep geological disposal, and the ways in which this
confidence can be obtained and communicated, are topics of great importance to the radioactive waste
management community.1
The technical aspects of confidence have been the subject of considerable debate, especially
the concept of model validation. It has, for example, been pointed out that it is impossible to describe
fully the evolution of an open system, such as a repository and its environment, that cannot be
A Stochastic Method for Estimating the Effect of Isotopic Uncertainties in Spent Nuclear Fuel
A Stochastic Method for Estimating the Effect of Isotopic Uncertainties in Spent Nuclear Fuel
This report describes a novel approach developed at the Oak Ridge National Laboratory
(ORNL) for the estimation of the uncertainty in the prediction of the neutron multiplication factor
for spent nuclear fuel. This technique focuses on burnup credit, where credit is taken in criticality
safety analysis for the reduced reactivity of fuel irradiated in and discharged from a reactor.
Validation methods for burnup credit have attempted to separate the uncertainty associated with
Standards & Regulations for the Geologic Disposal of Spent Nuclear Fuel and High-Level Waste
Standards & Regulations for the Geologic Disposal of Spent Nuclear Fuel and High-Level Waste
This paper draws on my experience as a reviewer of the scientific programs and performance assessments of the geological repository for transuranic waste at the Waste Isolation Pilot Plant in New Mexico and the proposed repository for spent nuclear fuel and high-level waste at Yucca Mountain in Nevada. In addition, I have served on numerous committees of the National Research Council that have addressed many aspects of nuclear waste management.
Prediction of the Isotopic Composition of UO2 Fuel from a BWR: Analysis of the DU1 Sample from the Dodewaard Reactor
Prediction of the Isotopic Composition of UO2 Fuel from a BWR: Analysis of the DU1 Sample from the Dodewaard Reactor
As part of a larger program to study mixed-oxide fuel subject to high burnup, some UO2 samples were exposed and analyzed. This report discusses results from the analysis of a UO sample that was burned in a boiling-water reactor (BWR) to approximately 57 GWd/t. The sample
Nuclear Waste Facility Siting and Local Opposition
Nuclear Waste Facility Siting and Local Opposition
On the historic evidence, but also for the distinctive qualities of the challenge, nuclear waste siting conflicts are assuredly among the most refractory in the large variety of NIMBY (Not In My Back Yard) facility siting disputes. Since the president brought the Yucca Mountain process to a halt in 2010 (or, more accurately, issued its death certificate), the search for a permanent waste fuel repository is at the starting line again.
U.S. Regulatory Recommendations for Actinide-Only Burnup Credit in Transport and Storage Casks
U.S. Regulatory Recommendations for Actinide-Only Burnup Credit in Transport and Storage Casks
In July 1999, the U.S. Nuclear Regulatory Commission (NRC) Spent Fuel Project Office
(SFPO) issued Interim Staff Guidance 8 Revision 1 (ISG8R1) to provide recommendations for the use
of burnup credit in storage and transport of pressurized-water reactor (PWR) spent fuel. Subsequent to
the issuance of ISG8R1, the NRC Office of Regulatory Research (RES) has directed an effort to
investigate the technical basis for extending the criteria and recommendations of ISG8R1 to allow
Management of Commercially Generated Radioactive Waste
Management of Commercially Generated Radioactive Waste
In the course of producing electrical power in light water.reactors (LWRs), the uranium
fuel accumulates fission products until the fission process is no longer efficient for power
production. At that point the fuel is removed from the reactor and stored in water basins
to allow radioactivity to partially decay before further disposition. This fuel is referred
to as "spent fuel." Although spent fuel as At is discharged from a reactor is intensely
radioactive, it has been stored safely in moderate quantities for decades. Spent fuel could
Parametric Analysis of PWR Spent Fuel Depletion Parameters for Long-Term Disposal Criticality Safety
Parametric Analysis of PWR Spent Fuel Depletion Parameters for Long-Term Disposal Criticality Safety
Utilization of burnup credit in criticality safety analysis for long-term disposal of spent
nuclear fuel allows improved design efficiency and reduced cost due to the large mass of fissile
material that will be present in the repository. Burnup-credit calculations are based on depletion
calculations that provide a conservative estimate of spent fuel contents (in terms of criticality
potential), followed by criticality calculations to assess the value of the effective neutron
Disposal Criticality Analysis Methodology Topical Report Revision 2
Disposal Criticality Analysis Methodology Topical Report Revision 2
This topical report describes the approach to the risk-informed, performance-based methodology to be used for performing postclosure criticality analyses for waste forms in the Monitored Geologic Repository at Yucca Mountain, Nevada. The risk-informed, performance-based methodology will be used during the licensing process to demonstrate how the potential for postclosure criticality will be limited and to demonstrate that public health and safety are protected against postclosure criticality.
Assessment of Reactivity Margins and Loading Curves for PWR Burnup-Credit Cask Designs
Assessment of Reactivity Margins and Loading Curves for PWR Burnup-Credit Cask Designs
This report presents studies to assess reactivity margins and loading curves for pressurized water reactor
(PWR) burnup-credit criticality safety evaluations. The studies are based on a generic high-density 32-
assembly cask and systematically vary individual calculational (depletion and criticality) assumptions to
demonstrate the impact on the predicted effective neutron multiplication factor, keff, and burnup-credit
loading curves. The purpose of this report is to provide a greater understanding of the importance of
Assessment of Fission Product Cross-Section Data for Burnup Credit Applications
Assessment of Fission Product Cross-Section Data for Burnup Credit Applications
Past efforts by the Department of Energy (DOE), the Electric Power Research Institute (EPRI), the Nuclear Regulatory Commission (NRC), and others have provided sufficient technical information to enable the NRC to issue regulatory guidance for implementation of pressurized-water reactor (PWR) burnup credit; however, consideration of only the reactivity change due to the major actinides is recommended in the guidance.
Range of Applicability and Bias Determination for Postclosure Criticality of Commercial Spent Nuclear Fuel
Range of Applicability and Bias Determination for Postclosure Criticality of Commercial Spent Nuclear Fuel
The purpose of this calculation report, Range of Applicability and Bias Determination for Postclosure
Criticality of Commercial Spent Nuclear Fuel, is to validate the computational method used to perform
postclosure criticality calculations. The validation process applies the criticality analysis methodology
approach documented in Section 3.5 of the Disposal Criticality Analysis Methodology Topical Report.1
The application systems for this validation consist of waste packages containing transport, aging, and
Identification, Description, and Characterization of Existing and Alternative Nuclear Energy Systems
Identification, Description, and Characterization of Existing and Alternative Nuclear Energy Systems
Fundamentally, a nuclear energy system uses nuclear fission to create heat, which is then available for generating electricity or other applications, including seawater desalination, heating, and production of other fuels. The nuclear energy system as currently deployed in the United States, Figure 1, consists of a number of integrated components, beginning with the natural resources required for nuclear fuel, followed by fissioning of the fuel in reactors connected to electricity generation facilities, and ending with the disposition of all wastes, including used nuclear fuel (UNF).
Proposed Alternative Strategy for the Department of Energy's Civilian Radioactive Waste Management Program: A Task Force Report
Proposed Alternative Strategy for the Department of Energy's Civilian Radioactive Waste Management Program: A Task Force Report
Over the decade since NWPA, the disposal
program's strategy, based on its interpretation of the
legislative mandate and regulatory requirements, has
sought:
• in a single large step and under a tight
schedule, to achieve the first-of-a-kind licensing
of a first-of-a-kind repository for isolating
wastes from the human environment for many
thousands of years.
• in a single large step and as rapidly as possible,
to build a full-scale repository and begin
disposing of the bulk of the nation's inventory
Civilian Nuclear Spent Fuel Temporary Storage Options
Civilian Nuclear Spent Fuel Temporary Storage Options
The Department of Energy (DOE) is studying a site at Yucca Mountain, Nevada, for a
permanent underground repository for highly radioactive spent fuel from nuclear reactors,
but delays have pushed back the facility’s opening date to 2010 at the earliest. In the
meantime, spent fuel is accumulating at U.S. nuclear plant sites at the rate of about 2,000
metric tons per year. Major options for managing those growing quantities of nuclear spent
fuel include continued storage at reactors, construction of a DOE interim storage site near
STARBUCS: A Prototypic SCALE Control Module for Automated Criticality Safety Analyses Using Burnup Credit
STARBUCS: A Prototypic SCALE Control Module for Automated Criticality Safety Analyses Using Burnup Credit
STARBUCS is a new prototypic analysis sequence for performing automated criticality safety analyses of spent fuel systems employing burnup credit. A depletion analysis calculation for each of the burnup-dependent regions of a spent fuel assembly, or other system containing spent fuel, is performed using the ORIGEN-ARP sequence of SCALE. The spent fuel compositions are then used to generate resonance self-shielded cross sections for each region of the problem, which are applied in a three-dimensional criticality safety calculation using the KENO V.a code.
Parametric Study of the Effect of Control Rods for PWR Burnup Credit
Parametric Study of the Effect of Control Rods for PWR Burnup Credit
The Interim Staff Guidance on burnup credit for pressurized water reactor (PWR) spent nuclear fuel (SNF), issued by the United States Nuclear Regulatory Commission's (U.S. NRC) Spent Fuel Project Office, recommends the use of analyses that provide an "adequate representation of the physics" and notes particular concern with the "need to consider the more reactive actinide compositions of fuels burned with fixed absorbers or with control rods fully or partly inserted." In the absence of readily available information on the extent of control rod (CR) usage in U.S.
Report to Congress on Reassessment of the Civilian Radioactive Waste Management Program
Report to Congress on Reassessment of the Civilian Radioactive Waste Management Program
The success of the Civilian Radioactive Waste Management Program of the U.S.
Department of Energy (DOE) is critical to U.S. ability to manage and dispose of
nuclear waste safely--and to the reestablishment of confidence in the nuclear energy
option in the United States. The program must conform with all applicable standards
and, in fact, set the example for a national policy on the safe disposal of radioactive
waste.
The Secretary of Energy has recently completed an extensive review of the
Sensitivity and Uncertainty Analysis of Commercial Reactor Criticals for Burnup Credit
Sensitivity and Uncertainty Analysis of Commercial Reactor Criticals for Burnup Credit
The purpose of this study is to provide insights into the neutronic similarities that may exist between a
generic cask containing typical spent nuclear fuel assemblies and commercial reactor critical (CRC) state-
points. Forty CRC state-points from five pressurized-water reactors were selected for the study and the
type of CRC state-points that may be applicable for validation of burnup credit criticality safety
calculations for spent fuel transport/storage/disposal systems are identified. The study employed cross-
End Effect keff Cias Curve for Actinide-Only Burnup Credit Casks
End Effect keff Cias Curve for Actinide-Only Burnup Credit Casks
A conservative end effect keff bias curve for actinide-only burnup credit casks is presented
in this paper. Rather than performing axially burnup-dependent analysis, cask designers can, if
they choose to, analyze casks with a uniform axial burnup (at assembly average burnup value) and
add the keff bias values to conservatively bound the actinide-only end effect. Earlier studies
suggested 1-3% increase in keff to account for the end effect, but they included fission products
as well as actinides for their analyses.
Transportation and Storage Subcommittee Report to the Full Commission DRAFT
Transportation and Storage Subcommittee Report to the Full Commission DRAFT
The main question before the Transportation and Storage Subcommittee was whether the United States
should change its approach to storing and transporting spent nuclear fuel (SNF) and high-level
radioactive waste (HLW) while one or more permanent disposal facilities are established.
To answer this question and to develop specific recommendations and options for consideration by the
full Commission, the Subcommittee held multiple meetings and deliberative sessions, visited several
Review of Information for Spent Nuclear Fuel Burnup Confirmation
Review of Information for Spent Nuclear Fuel Burnup Confirmation
The Interim Staff Guidance on burnup credit (ISG-8, revision 2) for pressurized-water-reactor spent
nuclear fuel in storage and transport casks, issued in 2002 by the U.S. Nuclear Regulatory Commission’s
Spent Fuel Project Office, recommends an out-of-core burnup measurement to confirm the reactor record
and compliance with the assembly burnup value used for cask loading acceptance. This recommendation
is intended to prevent unauthorized loading (i.e., misloading) of assemblies due to inaccuracies in reactor