ML20325A257

Amendment No. 3 to Certificate of Compliance No. 1040 for the HI-STORM 100 Umax Canister Storage System - Request for Additional Information

ML20325A257
Person / Time
Site:	HI-STORM 100
Issue date:	11/20/2020
From:	Yen-Ju Chen Storage and Transportation Licensing Branch
To:	Manzione K Holtec
YJChen - NMSS/DFM/STLB - 301.415.1018
References
CAC 001028, EPID L-2017-LLA-0033
Download: ML20325A257 (6)

Text

November 20, 2020 Ms. Kimberly Manzione Licensing Manager Holtec International Krishna P. Singh Technology Campus One Holtec Boulevard Camden, NJ 08104

SUBJECT:

AMENDMENT NO. 3 TO CERTIFICATE OF COMPLIANCE NO. 1040 FOR THE HI-STORM 100 UMAX CANISTER STORAGE SYSTEM - REQUEST FOR ADDITIONAL INFORMATION

Dear Ms. Manzione:

By letter dated August 30, 2016 1, and supplemented by letters dated September 9, 2016 2, November 4, 2016 3, March 3, 2017 4, August 4, 2017 5, February 1, 2018 6, May 23, 2018 7, October 16, 2018 8, December 15, 2019 9, and March 31, 2020 10, Holtec International submitted an amendment request to the U.S. Nuclear Regulatory Commission for the HI-STORM UMAX Canister Storage System, Certificate of Compliance (CoC) No. 1040.

The NRC staff issued a request for additional information (RAI) on September 30, 2019.

Subsequently, the staff learned that the criticality RAIs were based on Holtecs earlier submitted information and some of the criticality RAIs are not applicable anymore. The enclosed criticality RAIs replace RAIs 21 through 23 in the September 30, 2019, RAI, and the staff withdraws RAIs 24 and 25. Per your request on the response due date, we ask that you provide the response to the RAI within 60 days from the date of this letter. If you are unable to meet this deadline, please notify us in writing, within two weeks of receipt of this letter, of your new submittal date and the reasons for the delay.

The NRC staff continues evaluating Holtecs response to RAIs. We have revised the schedule based on the current progress. We anticipate resolving all issues in April 2021 and issue the preliminary safety evaluation report in July 2021.

1 Agencywide Document Access and Management System (ADAMS) Accession No. ML16250A404.

2 ADAMS Accession No. ML16258A213.

3 ADAMS Accession No. ML16313A170.

4 ADAMS Accession No. ML17067A058.

5 ADAMS Accession No. ML17229B194.

6 ADAMS Accession No. ML18036A222.

7 ADAMS Accession No. ML18150A340.

8 ADAMS Accession No. ML18304A159.

9 ADAMS Accession No. ML20002A299.

10 ADAMS Accession No. ML20104C047.

K. Manzione 2 Please reference Docket No. 72-1040, CAC No. 001028 and EPID No. L-2017-LLA-0033 in future correspondence related to this licensing action. If you have any questions, please contact me at 301-415-1018.

Sincerely, Digitally signed by Yen-Ju Yen-Ju Chen Date: 2020.11.20 Chen 14:17:21 -05'00' Yen-Ju Chen, Sr. Project Manager Storage and Transportation Licensing Branch Division of Fuel Management Office of Nuclear Material Safety and Safeguards Docket No.: 72-1040 CAC No.: 001028 EPID No.: L-2017-LLA-0033

Enclosure:

Request for Additional Information

K. Manzione 3

SUBJECT:

AMENDMENT NO. 3 TO CERTIFICATE OF COMPLIANCE NO. 1040 FOR THE HI-STORM 100 UMAX CANISTER STORAGE SYSTEM - REQUEST FOR ADDITIONAL INFORMATION DATE: November 20, 2020 DISTRIBUTION:

DFM r/f ADAMS Accession Number: ML20325A257 *via email OFFICE NMSS/DFM NMSS/DFM NMSS/DFM NMSS/DFM NMSS/DFM NAME YChen WWheatley* JSmith* RChang* JMcKirgan DATE 11/19/2020 9/10/2020 11/6/2020 11/6/2020 11/13/2020 OFFICIAL RECORD COPY

Request for Additional Information Docket No. 72-1040 Holtec International HI-STORM UMAX Canister Storage System Certificate of Compliance No. 1040 Amendment No. 3 The U.S. Nuclear Regulatory Commission staff issued a request for additional information (RAI) on September 30, 2019. The enclosed criticality RAIs replace RAIs 21 through 23 in the September 30, 2019, RAI. Each question describes information needed by the staff to complete its review of the application and to determine whether the applicant has demonstrated compliance with regulatory requirements in 10 CFR Part 72.

Criticality Evaluation RAI-21 Provide additional justification or analyses to support how the 24PT1-DSC meets the criteria of double contingency within the proposed HI-STORM UMAX amendment.

The proposed HI-STORM UMAX amendment has no discussion or analysis that addresses double contingency (e.g., water intrusion) into the 24PT1-DSC. The safety basis submitted by the applicant, and stated throughout Supplement I.6 of the FSAR, is that the 24PT1-DSC is only analyzed for dry conditions, which the applicant believes leads to a sufficient margin of safety to address uncertainties in its approach. This approach does not adequately address the double contingency principle due to the unanalyzed condition of the 24PT1-DSC stored in an underground vertical configuration and does not provide for defense in depth.

The requirement in 10 CFR 72.124(a) states "Spent fuel handling, packaging, transfer, and storage systems must be designed to be maintained subcritical and to ensure that, before a nuclear criticality accident is possible, at least two unlikely, independent, and concurrent or sequential changes have occurred in the conditions essential to nuclear criticality safety. This criterion is also stated in the American National Standards Institute (ANSI)/American Nuclear Society (ANS) 8.1, Nuclear Criticality Safety in Operations with Fissionable Materials Outside Reactors. Two unlikely events need to be identified and the system has to be designed in order to be subcritical given one unlikely event occurs (e.g., water intrusion into canister). This is important for evaluating criticality safety since the applicants analysis relies on only one parameter (i.e., maintaining a dry internal configuration), and does not address any failure mechanisms that may challenge this configuration. This is especially important due to the now underground placement of the canister in the UMAX system, which differs from the original 24PT1-DSC analyses completed by TransNuclear for the NUHOMS system. The applicant has not provided a separate analysis related to double contingency for this proposed amendment.

Further, the review for the MPC stored in the UMAX, Amendment 0 system for double contingency took into account the known engineering features that contributed to the overall safety of the system, including the materials, initial conditions (manufacturing, closing), the physical protection of the MPC, as well as the potential for stress corrosion cracking of the MPC and the effects of mechanical impacts compromising the containment boundary to justify the unlikelihood of water entering into the Enclosure

2 cannister. These same engineering features are not specified in the analysis provided by the applicant for the 24PT1-DSC.

This information is needed to evaluate compliance with 10 CFR 72.124(a).

RAI-22 Provide information on how loading and unloading conditions will be handled for the 24PT1-DSC when stored in the HI-STORM UMAX. In addition, provide information as to how fuel contained in the 24PT1-DSC would be transportable.

The application does not contain any postulated accident condition analysis associated with loading and unloading conditions with respect to their submitted criticality safety analysis. Fuels may experience any number of perturbations (e.g. fuel reconfigurations, damage to the cannister, etc.) that may challenge the criticality safety of the canister during onsite movement of the 24PT1-DSC. This information is necessary to ensure that any stored fuel can be removed at a later date.

This information is needed to evaluate the compliance with 10 CFR 72.236(b), as well as 72.236(m).

RAI-23 Justify the modeling of accident conditions used in Supplement I.6 of the FSAR to evaluate the reactivity of the 24PT1-DSC.

The applicant modeled one configuration of fuel assemblies, neglecting all internal components, and does not include any internal structural design information for the 24PT1-DSC in Supplement I.6 as required by 10 CFR 72.236(b). It is unclear to NRC staff whether this is a bounding configuration for criticality.

In addition, the applicant does not evaluate perturbations to the system with regard to accident conditions, including shifting of contents and damaged fuel assemblies as described in Section I.6.4.3 of the FSAR commensurate with the modeling methodology used for other approved canisters in the UMAX system. This deviation from the methodology currently used for other canisters authorized for use in the UMAX system should be adequately justified and provide enough information to determine the safety of the 24PT1-DSC during possible fuel reconfiguration due to postulated accident events (e.g., tolerances, fuel shifting, bounding configurations, etc.) as well as any potential fuel damage that may occur.

In addition, the applicant claims that the safety margin is substantial and is sufficient to address any uncertainties not explicitly considered within the FSAR. Staff is unable to make this same determination based on the information provided by the applicant. Without additional analyses by the applicant that demonstrate that this is the most reactive configuration of the fuel, the staff is unable to determine the 24PT1-DSC is subcritical in the HI-STORM UMAX. The applicants approach does not provide information on known uncertainties in canister construction and tolerances, nor a bounding analysis, that can be used for the staff to consider the safety margins of the actual nuclear criticality parameters in its assessment of keff for the proposed storage system. While NRC staff has analyzed the safety of the 24PT1-DSC in a TN NUHOMS system, the analyses have not been independently provided by the applicant for NRC staff to make similar findings for the 24PT1-DSC in the proposed UMAX amendment.

3 This information is needed by the staff to determine compliance with 10 CFR 72.236(a), 72.236(b), 72.236(c), and 10 CFR 72.124(a).