ML21029A107

HI-STORM 100 CoC Renewal Clarification RAIs

ML21029A107
Person / Time
Site:	Holtec
Issue date:	02/18/2021
From:	Kristina Banovac Storage and Transportation Licensing Branch
To:	Manzione K Holtec
KLBanovac - NMSS/DFM/STL - 301.415.7116
References
CAC 001028, EPID L-2020-RNW-0007
Download: ML21029A107 (9)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 February 18, 2021 Ms. Kimberly Manzione Licensing Manager Holtec International Holtec Technology Campus One Holtec Boulevard Camden, NJ 08104

SUBJECT:

REQUEST FOR CLARIFICATION OF RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION FOR THE TECHNICAL REVIEW OF THE APPLICATION FOR RENEWAL OF THE CERTIFICATE OF COMPLIANCE NO.

1014 FOR THE HI-STORM 100 STORAGE CASK SYSTEM (CAC/EPID NOS.

001028/L-2020-RNW-0007)

Dear Ms. Manzione:

By letter dated January 31, 2020, Holtec International (Holtec) submitted to the U.S. Nuclear Regulatory Commission (NRC) an application for renewal of the Certificate of Compliance (CoC) No. 1014 for the HI-STORM 100 Storage Cask System (Agencywide Documents Access and Management System (ADAMS) Accession No. ML20049A081). The NRC staff sent a request for additional information (RAI) related to the technical review of the renewal application on August 17, 2020 (ADAMS Accession No. ML20231A290), to which you responded on October 16, and October 29, 2020 (ADAMS Accession Nos. ML20290A819 and ML20303A254). The NRC staff reviewed Holtecs RAI responses and determined that the enclosed clarifications to the RAI responses are needed for the NRC staff to complete its technical review.

Discussion of this request for clarification occurred on February 5 and 17, 2021. We request that you provide this information within 60 days from the date of this letter. Inform us at your earliest convenience, but no later than 2 weeks before the response date, if you are not able to provide the information by that date. To assist us in rescheduling your review, you should include a new proposed submittal date and the reasons for the delay.

K. Manzione 2 Please reference Docket No. 72-1014 and CAC/EPID Nos. 001028/L-2020-RNW-0007 in future correspondence related to this request. The NRC staff is available to clarify these questions, and if necessary, to meet and discuss your proposed responses. If you have any questions regarding this matter, please contact me at 301-415-7116 or Kristina.Banovac@nrc.gov.

Sincerely, Kristina L. Digitally signed by Kristina L.

Banovac Banovac Date: 2021.02.18 14:01:18

-05'00' Kristina L. Banovac, Project Manager Storage and Transportation Licensing Branch Division of Fuel Management Office of Nuclear Material Safety and Safeguards Docket No.: 72-1014 CAC/EPID Nos.: 001028/L-2020-RNW-0007

Enclosure:

Request for Clarification cc: Brian Seawright, Holtec

K. Manzione 3

SUBJECT:

REQUEST FOR CLARIFICATION OF RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION FOR THE TECHNICAL REVIEW OF THE APPLICATION FOR RENEWAL OF THE CERTIFICATE OF COMPLIANCE NO.

1014 FOR THE HI-STORM 100 STORAGE CASK SYSTEM (CAC/EPID NOS.

001028/L-2020-RNW-0007)

DOCUMENT DATE: February 18, 2021 DISTRIBUTION:

NMSS/DFM r/f CMarkley, NMSS CJacobs, NMSS JWise, NMSS ZLi, NMSS G:\SFST\HI-STORM 100\CoC Renewal\RAI\HI-STORM 100 CoC renewal clarification RAI.docx ADAMS Accession Number: ML21029A107 *concurrence via email OFFICE NMSS/DFM/STL NRR/DNRL/NVIB NMSS/DFM/NARAB NMSS/DFM/IOB NAME KBanovac* OYee* EGoldfeiz* MDavis*

DATE 1/28/2021 1/28/2021 1/28/2021 1/28/2021 OFFICE NMSS/DFM/STL NMSS/DFM/MSB NMSS/DFM/NARAB NMSS/DFM/IOB NAME WWheatley* TBoyce* RChang* LCuadrado*

DATE 1/28/2021 1/29/2021 2/3/2021 2/5/2021 OFFICE NMSS/DFM/STL NAME JMcKirgan*

DATE 2/18/2021 OFFICIAL RECORD COPY

Request for Clarification Holtec International Docket No. 72-1014 Certificate of Compliance Renewal By letter dated January 31, 2020, Holtec International (Holtec) submitted to the U.S. Nuclear Regulatory Commission (NRC) an application for renewal of the Certificate of Compliance (CoC) No. 1014 for the HI-STORM 100 Storage Cask System (Agencywide Documents Access and Management System (ADAMS) Accession No. ML20049A081). The NRC staff sent a request for additional information (RAI) related to the technical review of the renewal application on August 17, 2020 (ADAMS Accession No. ML20231A290), to which Holtec responded on October 16, and October 29, 2020 (ADAMS Accession Nos. ML20290A819 and ML20303A254).

This request for clarification of RAI responses identifies information needed by the NRC staff to complete its technical review of the renewal application and to determine whether the applicant has demonstrated compliance with the regulatory requirements. The requested information is listed by RAI response number.

RAI 2-6 Follow-up Provide a justification for the acceptance criteria in the 100U Concrete aging management program (AMP) for radiation surveys for detecting degradation of subgrade shielding material (i.e., soil).

In response to RAI 2-6, the applicant updated the 100U Concrete AMP to include dose rate measurements for monitoring the degradation of the subgrade shielding material. The subgrade is credited in the shielding analyses of the HI-STORM 100 Final Safety Analysis Report (FSAR).

The applicant stated in the AMP that the acceptance criteria for radiation surveys are dose rates that are less than a 10% increase from the previously measured dose rates.

The staff needs to understand the basis for this acceptance criteria. Based on the comparison of the ranking of the dominating isotopes as cooling time increases, as presented in Table 11 of NUREG/CR-6700, Nuclide Importance to Criticality Safety, Decay Heating, and Source Terms Related to Transport and Interim Storage of High-Burnup LWR Fuel (ADAMS Accession No. ML010330186), the staff expects to see that dose rates decrease with time, if soil integrity is maintained. Additionally, it is unclear to NRC staff as to whether the 10% increase from previously measured dose rates will be compared to a baseline measurement, or will be compared to the last survey. If the 10% increase acceptance value is based on the last survey rather than a baseline measurement, provide justification that this would provide adequate management of potential degradation to the subgrade shielding material over the period of extended operation.

The staff needs this information to determine if the HI-STORM 100U meets the regulatory requirements of 10 CFR 72.240(c).

RAI 3-5 Follow-up Clarify the discrepancy between the renewal application and FSAR for the fabrication material for the Overpack Lid Stud.

Enclosure

The applicant responded to RAI 3-5 and indicated that the material for the Lid Stud in Table 3.3-2 has been changed to SA 193B7/ SA 564630 to match the material specification from FSAR Table 2.2.6 and licensing drawing BM1575.

The staff reviewed the Lid Stud component in Table 3.32 of the revised renewal application (i.e., HI-2188877, Rev. 0A) and noted the material is listed as SA 564630/SA 193B8, which is inconsistent with the applicants response to RAI 3-5 and FSAR Table 2.2.6. SA-193 grades B7 and B8 are chromium-molybdenum and austenitic stainless steels, respectively, and thus they may be susceptible to different aging mechanisms.

This information is required to demonstrate compliance with 10 CFR 72.240(c).

RAI 3-6 Follow-up Provide additional justification to demonstrate that the HoltiteA qualification tests support the conclusion that cracking due to radiation embrittlement, loss of fracture toughness and loss of ductility due to thermal aging, and loss of shielding due to boron depletion are not credible aging effects for the HoltiteA components in the HI-STORM 100 system during the period of extended operation.

The applicant responded to RAI 3-6 by revising its renewal application (i.e., HI-2188877, Rev. 0A) to include reference to Holtec Report HI-2002396, Holtite-A: Development History and Thermal Performance Data, Revision 5, as a form of supporting analysis to address potential aging mechanisms for Holtite-A. The applicant indicated in its response that this report demonstrates bounding conditions for HoltiteA qualification tests in terms of radiation flux and temperature and concluded that HoltiteA is thermally stable for use in the HISTORM 100 cask and is suitable for the radiation exposure expected throughout the period of extended operation.

However, the applicant did not adequately address the staffs request in RAI 3-6. Specifically, the applicant did not provide adequate information to demonstrate that the conclusions from the HoltiteA qualification tests discussed in Holtec Report HI-2002396 are applicable or bounding when compared to the cumulative radiation and thermal exposures that will be experienced by the Holtite-A components in the HI-STORM 100 system during the period of extended operation.

For example, information regarding the cumulative radiation and thermal exposures of the HI-STORM 100 system through the period of extended operation are not available to the staff for comparison with the qualification tests. Provide this comparison and supporting justification, so the staff is able to assess the applicants basis that cracking due to radiation embrittlement, loss of fracture toughness and loss of ductility due to thermal aging, and loss of shielding due to boron depletion are not credible aging effects for the HoltiteA components in the HI-STORM 100 system during the period of extended operation.

This information is required to demonstrate compliance with 10 CFR 72.240(c).

RAI 3-12 Follow-up Provide a justification for why thermal aging of the Basket Shims and Solid Shims is not a credible aging effect that could challenge the shims structural function during off-normal and accident conditions.

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The applicant provided its response to RAI 3-12 related to the Basket Shims and Solid Shims for the multi-purpose canister (MPC)68M/32M. The applicant indicated that the aluminum alloy basket shims and solid shims used in the MPC do not bear any load under normal conditions of storage [emphasis added] except for any shortterm operations when the cask is transferred horizontally, and the shims are subjected to lateral acceleration from the fuel basket and contained fuel. Thus, the applicant determined that, since the basket shims and solid shims do not bear any load during the period of extended operation, thermal aging is not considered credible and revised the renewal application accordingly.

However, the staff noted that the applicant did not address the intended functions of the Basket Shims and Solid Shims for the MPC68M/32M during off-normal and accident conditions

[emphasis added] during the period of extended operation. For example, FSAR Section 3.1.2.1.2 and Table 3.1.3 describes accident condition loading scenarios for the fuel basket, and it is unclear to the staff whether a change in aluminum properties due to thermal aging would affect the basket performance in these events.

This information is required to demonstrate compliance with 10 CFR 72.240(c).

MPC AMP RAI #2 Follow-up Revise the renewal application to clearly specify that the visual examinations performed as part of the MPC AMP will be in accordance with ASME Code Section XI, Article IWA-2200, VT-1 and VT-3. Otherwise, revise the renewal application to indicate a site-specific non-Code procedure that will be used along with a description of the inspection controls (e.g., lighting, distance, resolution) that are required to ensure that the aging effects can be detected.

In response to MPC AMP RAI #2, the applicant revised its MPC AMP in the revised renewal application (i.e., HI-2188877, Rev. 0A). Specifically, Program Element 4 - Detection of Aging Effects of the MPC AMP in the revised renewal application states Visual examination procedures should [emphasis added] follow ASME Code Section XI, Article IWA-2200 for VT-1 and VT-3 examinations.

The staff noted that use of visual examination procedures consistent with ASME Code Section XI, Article IWA-2200 for VT-1 and VT-3 examinations for the MPC AMP appears to be left to the discretion of the CoC holder or a general licensee implementing the AMP. The staff requires clarity on whether the AMP includes ASME Code inspections. If the intent is to provide an option in the AMP to follow a site-specific non-Code procedure, then revise the AMP to describe the inspections controls (e.g., lighting, distance, resolution) that are required to ensure that the aging effects can be detected.

This information is required to demonstrate compliance with 10 CFR 72.240(c).

100U Concrete AMP RAI #1 Follow-up (1) Provide a justification that groundwater chemistry monitoring of the 100U Concrete AMP can directly manage concrete degradation. Otherwise, revise the renewal application and clarify the purpose of the groundwater chemistry monitoring of the 100U Concrete AMP. (2) Revise the renewal application to clarify the discrepancy for the frequency of visual inspections conducted by the 100U Concrete AMP.

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In response to 100U Concrete AMP RAI #1 the applicant revised its 100U Concrete AMP and provided it in its revised renewal application (i.e., HI-2188877, Rev. 0A). The revised renewal application indicates that groundwater chemistry monitoring of the 100U Concrete AMP can directly manage concrete degradation. However, the staff noted that the purpose of the groundwater chemistry monitoring is to identify conditions (i.e., aggressive environment) that is conducive to belowgrade (underground) aging mechanisms. Thus, it is not clear how the groundwater chemistry monitoring of the 100U Concrete AMP directly manages concrete degradation. Specifically, the following is stated in the revised renewal application:

• Program Element 3 - Parameters Monitored/Inspected o For inaccessible areas, groundwater monitoring is performed every 5 years to determine if any degradation from the inaccessible portions is occurring.

• Program Element 4 - Detection of Aging Effects o Groundwater chemistry monitoring shall be performed every 5 years to determine if any degradation of the system from inaccessible areas is occurring.

• Program Element 6 - Acceptance Criteria o Any groundwater indications of concrete degradation will be entered into the corrective action program.

The staff notes that ACI 349.3R-02 (the standard cited by the AMP) includes groundwater chemistry monitoring to identify aggressive environments that may warrant increased concrete inspection frequency - not as a means to identify evidence of degradation.

Additionally, based on revisions to the 100U Concrete AMP, the staff noted a discrepancy in the frequency of inspections. Specifically, in Program Element 4 - Detection of Aging Effects, the 100U Concrete AMP indicates that the visual inspections will be conducted every 5 years and conducted annually.

This information is required to demonstrate compliance with 10 CFR 72.240(c).

RAI D-1 Follow-up Update the proposed FSAR supplement in Appendix D of the renewal application to include the following information:

a. In response to RAI D-1, Part 2, the applicant added references to the renewal application in the proposed FSAR supplement. In the FSAR supplement, the applicant includes reference 9.A.1 to the renewal application (HI-2188877, HI-STORM 100 License Renewal Application, Latest Revision) [emphasis added]. In a January 12, 2021, call (ADAMS Accession No. ML21025A332), the applicant noted that, per its quality assurance program, it would develop a final revision to HI-2188877 for its records after the CoC renewal becomes effective.

The NRC staff reviews the renewal application submitted on the docket, which forms the basis of NRCs decision on the renewal. In the safety evaluation report (SER) supporting the renewal decision, the NRC staff will reference the versions of the renewal application that it reviewed and based its renewal decision on (i.e., Rev. 0A of HI-2188877, or a future Rev. 0B if Holtec makes any changes in response to these clarification RAIs). Also, in NRCs oversight role, NRC inspectors would typically verify that the CoC holder implemented the conditions of the renewed CoC (e.g., that the CoC holder updated the FSAR with the proposed FSAR supplement provided in the renewal application that NRC 4

staff reviewed). Therefore, referencing the latest revision of the renewal application in the FSAR could result in inconsistencies with the version of the application that NRC staff reviewed, based its renewal decision on, and referenced in the SER. This could also create uncertainty for general licensees in their implementation of the renewed CoC, and for NRCs inspection of the CoC holders and general licensees implementation of the renewed CoC.

Revise the proposed FSAR supplement to incorporate by reference the specific version of the latest renewal application submitted on the docket or, alternatively, copy the referenced information into the FSAR.

b. In the proposed FSAR supplement, Table 9.A.1-1 MPC AMP, Element 10, there are 2 references to the renewal application that are not included in the proposed FSAR supplement (i.e., references C.1.1 and C.1.2 in the renewal application). Revise the proposed FSAR supplement to include those references.

This information is required to demonstrate compliance with 10 CFR 72.240(c).

RAI E-1 Follow-up:

Revise the proposed TS 5.8/5.4 and the proposed CoC condition #14 in Appendix E of the renewal application to include a clear timeframe for implementation by the CoC holder and general licensees.

a. Regarding the timing for development of procedures, the applicant provided revised language in the TS 5.8/5.4:

The general licensee shall establish and implement these written procedures within 365 days after the effective date of the renewal of the CoC or 365 days of the 20th anniversary of the loading of the first dry storage system at its site, whichever is later.

The applicant responded to RAI E-1, noting, The requirement in TS 5.4/5.8 was intended to cover the actual development of procedures and evaluations of the aging management program, which need to be implemented before the site enters the period of extended storage [emphasis added], but not necessarily at the same time that the renewed license is issued.

The NRC staff agrees that procedures should be implemented before the site enters the period of extended operation (PEO), which is consistent with the guidance in NUREG-1927, Section 3.6.3. However, the proposed TS language (i.e., 365 days of the 20th anniversary of the loading of the first dry storage system) may be overly prescriptive, in that it may not allow development of procedures earlier than 365 days before the PEO begins. In addition, it is not clear why performing this task 365 days after the PEO begins is a necessary option in the TS, given the clause already included in the proposed TS within 365 days after the effective date of the renewal of the CoC whichever is later addresses the scenario of a site that is already in the PEO (or is soon approaching it) when the renewed CoC is issued. It is also unclear why a site with potentially several years available to prepare their procedures would need the option to do so 365 days after the 20th anniversary of loading. Therefore, language similar to prior to entering the period of extended operation or no later than one year after the 5

effective date of the CoC renewal, whichever is later may be clearer for general licensees implementation of the renewed CoC.

b. Regarding the timing for update of the 10 CFR 72.212(b)(5) evaluation, the applicant noted that:

The Condition 14 requirements are for simple compliance with the renewed CoC.

When the NRC issues the renewed CoC, all users will have to update the 72.212 report to ensure they are referencing the renewed CoC, which supersedes the existing approved CoC, regardless of when that system was loaded. If this step is not performed, the site may be out of compliance with 72.214.

The NRC staff notes that the current proposed condition does not include a clear timeframe for when general licensees would update the 72.212 report. In a January 12, 2021, call (ADAMS Accession No. ML21025A332), the applicant clarified that it proposes that general licensees do this within 1 year after the effective date of the renewal.

The NRC staff notes that requiring all general licensees (including those not close to entering the PEO) to update the 72.212 report within 1 year after the effective date of renewal is inconsistent with NRCs guidance in NUREG-1927, Appendix E.2, which states:

The general licensee should update the 10 CFR 72.212(b)(5) evaluation before entering the period of extended operation [emphasis added]. Considering timely renewal provisions (See Section 1.4.5), update of the 10 CFR 72.212(b)(5) evaluation before the loaded systems enter the period of extended operation may not be possible. In such cases, the reviewer should ensure that timing for update of the 10 CFR 72.212(b)(5) evaluation is addressed in the application in a clear manner.

Therefore, language similar to, The general licensee shall complete this condition prior to entering the period of extended operation or no later than one year after the effective date of the CoC renewal, whichever is later may be clearer for general licensees implementation of the renewed CoC.

This information is required to demonstrate compliance with 10 CFR 72.240(c).

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