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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.
Computational Benchmark of SAS2D Against Spent Fuel Samples from the Takahama-3 Reactor
Computational Benchmark of SAS2D Against Spent Fuel Samples from the Takahama-3 Reactor
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:
Dry Transfer System for Spent Fuel: Project Report: A System Designed to Achieve the Dry Transfer of Bare Spent Fuel Between Two Casks
Dry Transfer System for Spent Fuel: Project Report: A System Designed to Achieve the Dry Transfer of Bare Spent Fuel Between Two Casks
Use of an on-site dry transfer system (DTS) allows utilities with limited crane capacities or other plant restrictions to take advantage of large efficient storage systems. By using this system, utilities can also transfer fuel from loaded storage casks to transport casks without returning to their fuel storage pool.
Failure Modes and Effects Analysis (FMEA) of Welded Stainless Steel Canisters for Dry Cask Storage Systems
Failure Modes and Effects Analysis (FMEA) of Welded Stainless Steel Canisters for Dry Cask Storage Systems
Due to the delayed opening of a final geological repository for spent nuclear fuel, the lifespan of dry cask storage systems may be increased to 120 years or longer. To ensure safety over this extended period of interim storage, degradation mechanisms that have the potential to cause penetration of the canister confinement boundary must be evaluated and understood.
NRC SFST ISG-2: Fuel Retrievability
NRC SFST ISG-2: Fuel Retrievability
This Interim Staff Guidance (ISG) provides guidance to the staff for determining if
storage systems to be licensed under 10 CFR Part 72 allow ready retrieval of spent fuel.
This guidance is not a regulation or a requirement.
NRC SFST ISG-8: Burnup Credit in the Criticality Safety Analyses of PWR Spent Fuel in Transportation and Storage Casks
NRC SFST ISG-8: Burnup Credit in the Criticality Safety Analyses of PWR Spent Fuel in Transportation and Storage Casks
Title 10 of the Code of Federal Regulations (10 CFR) Part 71, Packaging and Transportation of
Radioactive Material, and 10 CFR Part 72, Licensing Requirements for the Independent
Storage of Spent Nuclear Fuel, High-Level Radioactive Waste, and Reactor-Related Greater
Than Class C Waste, require that spent nuclear fuel (SNF) remain subcritical in transportation
and storage, respectively. Unirradiated reactor fuel has a well-specified nuclide composition
that provides a straightforward and bounding approach to the criticality safety analysis of
NRC SFST ISG-9: Storage of Components Associated with Fuel Assemblies
NRC SFST ISG-9: Storage of Components Associated with Fuel Assemblies
The purpose of this ISG is to clarify the technical criteria for types of materials that will be |
considered associated with the storage of spent fuel assemblies. While control rods are |
mentioned in the Standard Review Plan as possible contents, specific information and guidance
is lacking.
Revision 1
NRC SFST ISG-10: Alternatives to the ASME Code
NRC SFST ISG-10: Alternatives to the ASME Code
There is no existing American Society of Mechanical Engineers (ASME) Code for the design
and fabrication of spent fuel dry storage casks. Therefore, ASME Code Section III, is
referenced by NUREG-1536, “Standard Review Plan for Dry Cask Storage Systems,” as an
acceptable standard for the design and fabrication of dry storage casks. However, since dry
storage casks are not pressure vessels, ASME Code Section III, cannot be implemented
without allowing some alternatives to its requirements.
Revision 1
NRC SFST ISG-11: Cladding Considerations for the Transportation and Storage of Spent Fuel
NRC SFST ISG-11: Cladding Considerations for the Transportation and Storage of Spent Fuel
The staff has broadened the technical basis for the storage of spent fuel including assemblies
with average burnups exceeding 45 GWd/MTU. This revision to Interim Staff Guidance No. 11
(ISG-11) addresses the technical review aspects of and specifies the acceptance criteria for
limiting spent fuel reconfiguration in storage casks. It modifies the previous revision of the ISG
in three ways: (1) by clarifying the meaning of some of the acceptance criteria contained in
NRC SFST ISG-14: Supplemental Shielding
NRC SFST ISG-14: Supplemental Shielding
Guidance regarding supplemental shielding that may be installed at an independent
spent fuel storage installation (ISFSI) to meet the requirements of 10 CFR 72.104(a).
NRC SFST ISG-17: Interim Storage of Greater Than Class C Waste
NRC SFST ISG-17: Interim Storage of Greater Than Class C Waste
Guidance is necessary on the interim storage of greater than Class C (GTCC) waste due to the
revision of Title 10 of the Code of Federal Regulations (10 CFR) Part 72. The revision to 10
CFR Part 72 is documented in final rule, ìInterim Storage for GTCC Waste,î and permits the
storage of GTCC wastes at independent spent fuel storage installations (ISFSI) or monitored
retrievable storage (MRS) facilities. The GTCC wastes, if stored at an ISFSI, must be in solid
form, and stored in a separate container (i.e., GTCC waste may not be stored in a cask that
NRC SFST ISG-18: The Design and Testing of Lid Welds on Austenitic Stainless Steel Canisters as the Confinement Boundary for Spent Fuel Storage
NRC SFST ISG-18: The Design and Testing of Lid Welds on Austenitic Stainless Steel Canisters as the Confinement Boundary for Spent Fuel Storage
The purpose of this ISG is to address the design and testing of the various closure welds (“lid
welds”) associated with the redundant closure of all-welded austenitic stainless steel canisters:
As an acceptable confinement boundary under 10 CFR Part 72.236(e) (Ref. 1) for
purposes of demonstrating no credible leakage of radioactive material during storage
and satisfying the dose limits under normal and off-normal conditions in 10 CFR Parts
72.104(a) and 72.106(b).
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