NRC SFST ISG-5: Confinement Evaluation

Several changes have occurred since the issuance of NUREG-1536, “Standard Review Plan (SRP) for Dry Cask Storage Systems,” that affect the staff’s approach to confinement evaluation. The attachment to this ISG integrates the current staff approach into a revision of ISG-5. The highlights of the changes include: • Reflects October 1998 revisions to 10 CFR 72.104 and 10 CFR 72.106. • Expands and clarifies acceptance criteria associated with confinement analysis and acceptance of “leak tight” testing instead of detailed confinement analysis.

NRC SFST ISG-6: Establishing minimum initial enrichment for the bounding design basis fuel assembly(s)

The Standard Review Plan, NUREG-1536, Chapter 5, Section V, 2 recommends that “the applicant calculate the source term on the basis of the fuel that will actually provide the bounding source term,” and states that the applicant should, “either specify the minimum initial enrichment or establish the specific source terms as operating controls and limits for cask use.” A specified source term is difficult for most cask users to determine and for inspectors to verify.

NRC SFST ISG-7: Potential Generic Issue Concerning Cask Heat Transfer in a Transportation Accident

Staff raised two major issues concerning the adverse effects of fission gases to the gas-mixture thermal conductivity in a spent fuel canister in a post accident environment. The two major concerns were: (1) the reduction of the thermal conductivity of the canister gas by the mixing of fission gases expelled from failed fuel pins and (2) the resultant temperature and pressure rise within the canister. Since the fission gas is typically of a lower conductivity than the cover gas,

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

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

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

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-12: Buckling of Irradiated Fuel Under Bottom End Drop Conditions

Fuel rod buckling analyses under bottom end drop conditions have traditionally been performed to demonstrate integrity of the fuel following a cask drop accident. The methodology described by Lawrence Livermore National Laboratory (LLNL) to analyze the buckling of irradiated spent fuel assembly under a bottom end drop in their report UCID-21246 is a simplified approach. It assumed that buckling occurred when the fuel rod segment between the bottom two spacer grids reached the Euler buckling limit. The weight of fuel pellets was neglected in the analysis;

NRC SFST ISG-13: Real Individual

The purpose of this guidance is to, (1) clarify the meaning of a real individual as used in 10 CFR 72.104, (2) specify how the applicant may perform dose evaluations beyond the controlled area for site-specific and general Independent Spent Fuel Storage Installation (ISFSI) licenses, and (3) clarify standard review plan (SRP) text regarding dose calculations outside the controlled area.

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-15: MATERIALS EVALUATION

Due, in part, to a number of material-related issues identified during dry cask storage system (DCSS) and transportation package application reviews and field implementation, the staff has recognized the need for specific guidance for the review of materials selected by the applicant for its DCSS or transportation package.

NRC SFST ISG-16: Emergency Planning

Issuance of specific guidance for review of Emergency Plans for facilities licensed pursuant to 10 CFR Part 72 and removal of the reference to Regulatory Guide 3.67, "Standard Format and Content for Emergency Plans for Fuel Cycle and Materials Facilities," as included in NUREG- 1567, Standard Review Plan for Spent Fuel Dry Storage Facilities (March 2000).

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

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).

NRC SFST ISG-19: Moderator Exclusion under Hypothetical Accident Conditions and Demonstrating Subcriticality of Spent Fuel under the Requirements of 10 CFR 71.55(e)

This Interim Staff Guidance (ISG) provides review guidance for meeting the fissile material package standards in 10 CFR 71.55(e). The provisions of 71.55(e) require that a fissile material package be subcritical under hypothetical accident conditions assuming that the fissile material is in the most reactive credible configuration consistent with the damaged condition of the package and the chemical and physical form of the contents, and water moderation occurs to the most reactive credible extent consistent with the damaged condition of the package and

NRC SFST ISG-23: Application of ASTM Standard Practice C1671-07 when performing technical reviews of spent fuel storage and transportation packaging licensing actions

The standard review plans for storage of spent nuclear fuel and transportation of fissile materials do not address, in detail, the technical considerations for crediting the neutron absorber content of metal matrix composites used for preventing nuclear criticality. The Division of Spent Fuel Storage and Transportation (SFST) considers the application of acceptance criteria and methodology described in the recently developed American Standard for Testing and Materials (ASTM) standard practice C1671-07, “Standard Practice for Qualification and

NRC SFST ISG-20: Transportation Package Design Changes Authorized Under 10 CFR Part 71 Without Prior NRC Approval

Authority for licensees to transport radioactive material comes from 10 CFR Part 71. Licensees are authorized to transport Type B quantities and fissile materials in NRC-certified packages under the general license in 71.17. Unlike 10 CFR Part 72, Part 71 does not include change authority, that is, there is no specific Part 71 regulation that allows licensees to make changes in the design or operation of an NRC-certified package without prior NRC approval. However,

NRC SFST ISG-21: USE OF COMPUTATIONAL MODELING SOFTWARE

Given the growing industry need to store spent reactor fuel of increasingly higher burnups and heat loads in dry storage casks, and eventually to transport that same spent fuel in transportation packages, analyzing the performance of casks and other radioactive material packages has become a greater challenge. Finite Element, Finite Difference, and Finite Volume analysis computer codes, defined here as Computational Modeling Software (CMS), are tools used by many licensees to analyze cask and package performance in the structural

NRC SFST ISG-22: POTENTIAL ROD SPLITTING DUE TO EXPOSURE TO AN OXIDIZING ATMOSPHERE DURING SHORT-TERM CASK LOADING OPERATIONS IN LWR OR OTHER URANIUM OXIDE BASED FUEL

Under the current guidance in ISG-1, Revision 1, “Damaged Fuel,” the definition of intact fuel includes fuel rods containing no cladding defects greater than pinhole leaks or hairline cracks. During the cask water removal process parts of, or all of, the fuel rods will be exposed to a gaseous atmosphere. If the gaseous atmosphere is oxidizing, oxidation of fuel pellets or fuel fragments can occur if a cladding breach exists (such as a pinhole). Oxidation may occur

NRC SFST ISG-25: Pressure and Helium Leakage Testing of the Confinement Boundary of Spent Fuel Dry Storage Systems

The purpose of this interim staff guidance (ISG) is to supplement standard review plan guidance for evaluating the helium leakage testing and ASME Code1 required pressure (hydrostatic/pneumatic) testing that is specified for the dry storage system (DSS) confinement boundary. These acceptance tests are necessary to clearly demonstrate that the DSS confinement boundary has been fabricated in accordance with the design criteria, and that its operation complies with the intended safety bases of the confinement system and regulatory

Spent Fuel Transportation Applications— Assessment of Cladding Performance

This report summarizes the results of EPRI’s multi-year research effort to assess cladding performance under normal and hypothetical accident conditions of spent nuclear fuel transportation.

Fission Product Benchmarking for Burnup Credit Applications

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

Proposed Alternative Strategy for the Department of Energy's Civilian Radioactive Waste Management Program--A Task Force Report

In his January 12, 1993 letter to Senator Johnston, Secretary Watkins promised to develop a conceptual revised program strategy for public review. The enclosed document represents the final report of the Task Force on an Alternative Program Strategy that was established to fulfill that commitment. The report incorporates refinements to the preliminary draft you received on March 8, based on discussions with key people in the program. In developing this alternative strategy, the Task Force has drawn on the extensive analyses of

Managing Nuclear Waste-A Better Idea, A Report to the U.S. Secretary of Energy

When Congress passed the Nuclear Waste Policy Act of 1982, it created the Office of Civilian Radioactive Waste Management within the Department of Energy to spearhead the implementation of this landmark legislation. In Section 303 of the Act, however, Congress directed the Secretary of Energy to study alternative approaches to managing the radioactive waste program, as follows: ALTERNATIVE MEANS OF FINANCING SEC. 303. The Secretary shall undertake a study with respect to

Final Environmental Impact Statement, Management of Commercially Generated Radioactive Waste, Vol. 1