ML24109A251
| ML24109A251 | |
| Person / Time | |
|---|---|
| Site: | 07201032 |
| Issue date: | 03/01/2024 |
| From: | Holtec |
| To: | Office of Nuclear Material Safety and Safeguards |
| Shared Package | |
| ML24109A249 | List: |
| References | |
| 5018109 | |
| Download: ML24109A251 (1) | |
Text
Attachment 1 to Holtec Letter 5018109 Amendment Request 1032-10
SUMMARY
OF PROPOSED CHANGES All changes to the CoC and FSAR are marked in the subsequent attachments. Changes that have occurred as part of prior applications are not marked as changes.
Proposed Change #1 Introduce the HI-STORM FW Extended Configuration. This version of the HI-STORM FW system is an anchored configuration that allows storage of two MPCs stored vertically within a specially designed system of two storage overpacks.
Reason for Proposed Change #1 For some sites where space for ISFSI pad construction is limited, the Extended Configuration of the HI-STORM FW overpack allows for higher number of fuel assemblies to be stored in a given area. As sites operate longer time periods, the needed ISFSI space increases and this Extended Configuration provides a solution Justification for Proposed Change #1 The Extended Configuration of the HI-STORM FW system has been fully analyzed and demonstrated to meet the requirements of 10CFR72. The FSAR has been updated with supplement II, which provides the full description and analysis of the system. The structural integrity of the system is analyzed for all normal, off-normal, and accident events. The thermal model is based on the previously approved thermal models for the HI-STORM FW and is updated to account for the Extended Configuration. Similarly, the shielding calculations are based on the previously NRC approved models and methodologies and updated as needed for the Extended Configuration. The shielding evaluation demonstrates that the system can meet all of the required dose rates when installed on-site. Criticality is unchanged since the MPCs and baskets are not modified in the new overpack design. No new materials are introduced as part of this new configuration, and the new FSAR supplement describes the requirements for fabrication and operation of the system. The CoC has also been updated as needed to include the required controls and criteria for the new configuration.
Proposed Change #2 Incorporation of a methodology to develop site specific loading patterns in Chapter 4 of the HI-STORM FW FSAR and inclusion of higher maximum per canister and per cell limits for those patterns.
Reason for Proposed Change #2 The need to store fuel with higher per-assembly heat load fuels is projected to grow further as cask designers are challenged by shuttering nuclear plants. It has been determined that individually developed patterns would give more flexibility to loading plans. This loading pattern methodology is similar to the methodology developed in the NRC approved Thermal Topical Report HI-2200343.
Justification for Proposed Change #2 The methodology being used is similar to a methodology previously approved by the NRC. The heat load patterns are required to maintain compliance with the same acceptance criteria previously approved for the storage system. Therefore, the system maintains the same level of safety as the previously certified systems.
to Holtec Letter 5018109 Amendment Request 1032-10
SUMMARY
OF PROPOSED CHANGES Proposed Change #3 Incorporation of the Topical Report on the Radiological Fuel Qualification Methodology for Dry Storage Systems, Holtec Report HI-2210161-A. Related details and requirements are specified in the new Appendix B to Chapter 5 of the FSAR.
Reason for Proposed Change #3 Incorporating this topical report will increase flexibility in developing loading patterns and loading plans.
It will also simplify the analysis, review and approval process for this license amendment, and reduce the need for future license amendments.
Justification for Proposed Change #3 The process outlined in the FSAR is the implementation of the NRC reviewed topical report, which has been approved. Modifying the contents according to this methodology ensures that the shielding performance of the system continues to meet regulatory requirements.
Proposed Change #4 Reduced MPC-44 minimum cooling time from 3 years to 1 year, and MPC-37P minimum cooling time from 1.6 years to 1 year.
Reason for Proposed Change #4 Reducing the cooling times to 1 year will provide increased flexibility of loading MPCs and aligns the cooling time requirements for these baskets with those for all other baskets.
Justification for Proposed Change #4 This amendment introduces the use of the methodology in the Shielding Topical Report HI-2210161, Revision 4, (see Proposed Change #3). Based on that, no additional cooling time restriction is required for any of the baskets. The minimum value of 1 year is consistent with the requirement in 10CFR72, and only specified as a clarification. There is no change to the thermal or shielding performance of the system.
Editorial Changes:
Minor editorial changes were also made to the CoC.
Updated the MPC-89 Maximum Fuel Assembly Length in Table 2.1-1 to 181.5 inches. The maximum fuel length of 181.5 inches has already been included in the FSAR in previous amendments. Table 2.1.1a in Chapter 2 of the FSAR lists a maximum fuel assembly length of 181.5 inches so this change is only correcting information which had not been previously updated in the CoC