ML23283A124

Enclosure 1 (Public) - HI-STORM 100 Amd 18 - 2nd RAI Round

ML23283A124
Person / Time
Site:	Holtec
Issue date:	11/02/2023
From:	Storage and Transportation Licensing Branch
To:	Holtec
Shared Package
ML23283A123	List: ML23283A124 ML23283A126
References
EPID L-2022-LLA-0002, CAC 001028
Download: ML23283A124 (2)

Text

OFFICIAL USE ONLY PROPRIETARY INFORMATION Second Request for Additional Information for the HI-STORM 100 Amendment No. 18 Docket No. 72-1014 By letter dated December 15, 2021 (Agencywide Documents Access and Management System Accession No. ML21349B418), as supplemented September 2, 2022 (ML22245A103), Holtec International (Holtec) submitted an application to the U.S. Nuclear Regulatory Commission (NRC) for Certificate of Compliance No. 1014, Amendment No. 18, to the HI-STORM 100 System, pursuant to the requirements of Part 72 of Title 10 of the Code of Federal Regulations (10 CFR Part 72). On October 13, 2022, the application was accepted for a detailed technical review (ML22273A141).

On May 26, 2023, Holtec submitted its responses (ML23146A138) to the NRC staffs request for additional information (RAI) letter dated March 6, 2023 (ML23058A126).

On September 8, 2023 (ML23251A250), Holtec provided supplemental responses to the staffs first RAI pursuant to a clarification call held between Holtec and NRC staff on August 2, 2023 (ML23215A059).

This second RAI identifies information needed by the staff in connection with its review of the HI-STORM 100 Amendment No. 18.

Request for Additional Information (non-proprietary)

RAI 4-1 (Round 2): Clarify the following in section 1.0.3.1 of the updated final safety analysis report (UFSAR):

a. In the first bullet of step 2b, similar to the language that is used in the first bullet of step 2, clarify that all topical report acceptance criteria (including all temperatures and pressures from tables 2.1 and 2.2 of [1.0.7]) are met when using the Holtec Report No.

HI-2200343-A Topical Report (TR) Agencywide Documents Access and Management System Accession No. ML21302A147 (to be updated when TR is updated based on RAI 8-1 (Round 2). This evaluation should then be documented in step 3, similar to the documentation performed within step 3 for the evaluation performed in step 2c.

b. Describe what is meant by, as appropriate; in step 3 of section 1.0.3.1 of the UFSAR, or alternatively remove the phrase.

Although proposed steps 2a plus 2b, and separately step 2c of section 1.0.3.1 of the UFSAR come from two different prior NRC approvals (10 CFR 72.48 and the TR, respectively),

proposed steps 2a plus 2b are within the proposed change control process in section 1.0.3.1 of the UFSAR to allow for more flexibility in the use of the TR.

Proposed step 2b of section 1.0.3.1 of the UFSAR will demonstrate that the peak cladding temperature (PCT) is bounding in the thermal, invariant model, however, it is not clear in the application how it will be demonstrated that other component temperatures in the thermal, invariant model, are necessarily bounding. Regarding item a. above, the thermal, 72.48 model, is based on the thermal, invariant model, which is initially evaluated in proposed step 2 and later evaluated in step 2c in section 1.0.3.1 of the UFSAR. In addition, in proposed step 2b, the thermal, 72.48 model, with the candidate heat load pattern should be evaluated using the TR to ensure that the TR acceptance criteria are met for the, 72.48 model. This is because Enclosure 1 OFFICIAL USE ONLY PROPRIETARY INFORMATION

OFFICIAL USE ONLY PROPRIETARY INFORMATION the, 72.48 model, is the model that is proposed to be fabricated and used by the general licensee. This evaluation of the 72.48 model, should then be documented in step 3 to demonstrate that the TR acceptance criteria are met.

This information is needed to determine compliance with 10 CFR 72.236(f).

RAI 4-2 (Round 2): See proprietary enclosure RAI 8-1 (Round 2): Provide a revision to Holtec Topical Report HI-2200343-A, Table 2.1, SSC Temperature Limits for Evaluation of Candidate Heat Load Patterns, with corrected notes for the temperature limits for the multipurpose canister (MPC) shell, lid, closure ring, and baseplate temperature limits that addresses the normal, off-normal, and accident temperature limits if duplex stainless steels are used for the fabrication of these confinement boundary components.

The use of duplex stainless steels meeting the requirements of American Society of Mechanical Engineers (ASME) Code Case N-635-1 for unified numbering system (UNS) S31803 was approved in HI-STORM 100 Amendment No. 12 (ML18355A383). To support the amendment request, Holtec submitted HI-STORM 100 final safety analysis report (FSAR) Revision 14C (ML17333A686; Package ML17326A174). HI-STORM 100 FSAR revision 14C, table 2.2.3, Design Temperatures, included a note stating that, for MPC confinement barrier components manufactured using duplex stainless steel, the normal, off-normal and accident temperature limits (short-term events) were governed by the temperature limits in FSAR table 1.A.6, Duplex Stainless Steel Temperature Limits.

In response to RAI 8-1 (ML23058A126), Holtec submitted a revision to Holtec Topical Report HI-2200343-A on September 8, 2023. Table 2.1 included a note stating that, for MPC confinement barrier components manufactured using duplex stainless steel, the long term normal condition and short-term event temperature limits were governed by the temperature limits in FSAR table 1.A.6.

However, the revised table 2.1 did not contain a note referencing the temperature limits in FSAR table 1.A.6. for the off-normal and accident temperature limits. Therefore, the revision to table 2.1 is not consistent with the licensing basis duplex stainless steel temperature limits for the MPC shell, lid, closure ring, and baseplate (confinement boundary components) approved in HI-STORM 100, Amendment No. 12.

This information is needed to determine compliance with 10 CFR 72.236(b).

2 OFFICIAL USE ONLY PROPRIETARY INFORMATION