ML20267A345

Request for Clarification of Response to RAI for HI-STAR 100 CoC Renewal Application

ML20267A345
Person / Time
Site:	07201008
Issue date:	09/30/2020
From:	Kristina Banovac Storage and Transportation Licensing Branch
To:	Manzione K Holtec
KLBanovac NMSS/DFM/STL 301.415.7116
References
CAC 001028, EPID L-2018-RNW-0030
Download: ML20267A345 (7)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 September 30, 2020 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.

1008 FOR THE HI-STAR 100 STORAGE CASK SYSTEM (CAC/EPID NOS.

001028/L-2018-RNW-0030)

Dear Ms. Manzione:

By letter dated December 7, 2018, as supplemented on June 28, 2019, and October 10, 2019, Holtec International (Holtec) applied for renewal of the Certificate of Compliance (CoC) No.

1008 for the HI-STAR 100 Storage Cask System (Agencywide Documents Access and Management System (ADAMS) Accession Nos. ML18345A178, ML19184A232, and ML19288A089). The U.S. Nuclear Regulatory Commission (NRC) staff sent a request for additional information (RAI) related to the technical review of the renewal application on April 10, 2020 (ADAMS Accession No. ML20104A040), to which you responded on June 1, 2020 (ADAMS Accession No. ML20153A768). 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.

In addition, during the staffs review of the renewal application, Holtec submitted Revision 4 of the HI-STAR 100 Final Safety Analysis Report (FSAR), by letter dated March 11, 2020 (ADAMS Accession No. ML20071D992). This FSAR, Revision 4 includes the changes made in Amendment No. 3 to the CoC. The NRC staff considered these additional FSAR revisions in its review of the renewal application and has some questions regarding the revisions, which are included in the enclosed request for clarification.

Discussion of this request for clarification occurred on September 28, 2020. We request that you provide this information within 45 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. 72-1008 and CAC/EPID Nos. 001028/L-2018-RNW-0030 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: 2020.09.30 08:47:12 -04'00' Kristina L. Banovac, Project Manager Storage and Transportation Licensing Branch Division of Fuel Management Office of Nuclear Material Safety and Safeguards Docket No.: 72-1008 CAC/EPID Nos.: 001028/L-2018-RNW-0030

Enclosure:

Request for Clarification

ML20267A345 OFFICE NMSS/DFM/STL NMSS/DFM/MSB NMSS/DFM/STL NMSS/DFM/MSB NAME KBanovac JWise WWheatley TBoyce DATE 9/16/2020 9/17/2020 9/17/2020 9/22/2020 OFFICE NMSS/DFM/STL NAME BWhite for JMcKirgan DATE 9/23/2020 Request for Clarification Holtec International Docket No. 72-1008 Certificate of Compliance Renewal By letter dated December 7, 2018, as supplemented on June 28, 2019, and October 10, 2019, Holtec International (Holtec) applied for renewal of the Certificate of Compliance (CoC) No.

1008 for the HI-STAR 100 Storage Cask System (Agencywide Documents Access and Management System (ADAMS) Accession Nos. ML18345A178, ML19184A232, and ML19288A089). The U.S. Nuclear Regulatory Commission (NRC) staff sent a request for additional information (RAI) related to the technical review of the renewal application on April 10, 2020 (ADAMS Accession No. ML20104A040), to which you responded on June 1, 2020 (ADAMS Accession No. ML20153A768).

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.

Chapter 2: Scoping Evaluation RAI 2-3 and RAI 2-4 Follow-up Revise the scoping and aging management review (AMR) tables in the renewal application to clarify the responses to an NRC Observation and RAIs with respect to the subcomponents that were determined to be within scope of renewal.

The responses to NRC Observation 3 (Holtec, 2019) and RAIs 2-3 and 2-4 (Holtec, 2020) were provided to clarify which subcomponents were concluded to be within the scope of the renewal review and subject to an AMR. This clarity was sought to allow the staff to complete its review of the application and to ensure that the scoping and AMR tables (which are referenced in the aging management programs and in the proposed changes to the HI-STAR 100 Final Safety Analysis Report (FSAR) in Appendix D of the renewal application) provided an accurate description of the aging management activities in the period of extended operation.

The staff identified apparent discrepancies in the response to the Observation, responses to RAIs, and the scoping and AMR tables in the renewal application. As a result, revise the renewal application to clarify the following:

1. Revise Table 2.1-3 of the renewal application, MPC Basket Subcomponents, to provide a conclusion as to whether the Optional Heat Conduction Elements are within scope of the renewal. If these elements are concluded to not be within the scope (as stated in the response to RAI 2-3), remove them from Table 3.3-2, Aging Management Review of MPC Basket Subcomponents.

2. As appropriate, revise the scoping and AMR tables to ensure they accurately state the scoping conclusions of the following items for which the responses to Observation 3 and RAI 2-4 appear to differ:

Enclosure

• MPC Plugs for Drilled Holes

• MPC Upper Fuel Spacer Bolt

• MPC Basket Shim

• MPC Basket Support (Flat Plate)

• Overpack Thermal Expansion Foam This information is needed to confirm compliance with 10 CFR 72.240(c).

References Holtec, 2019. Attachment 1 to Holtec Letter 5014876, Submittal of Responses to NRCs RSIs on the Renewal of the HI-STAR 100 Storage CoC, Holtec International, ADAMS Accession No. ML19184A232. June 28, 2019.

Holtec, 2020. Attachment 1 to Holtec Letter 5014898, Submittal of Responses to NRCs RIs on the Renewal of the HI-STAR 100 Storage CoC, Holtec International, ADAMS Accession No. ML20153A768. June 1, 2020.

RAI 2-5 Revise the renewal application to include the changes to the design bases in the HI-STAR 100 FSAR, Revision 4, which is associated with Amendment No. 3 to the HI-STAR 100 CoC.

By letter dated March 11, 2020, the applicant submitted Revision 4 of the FSAR that includes the changes made in CoC Amendment No. 3 (ADAMS Accession No. ML20071D992).

However, some changes were not addressed in the renewal application. Revise the renewal application to:

1. Include the evaluation of subcomponents added in Amendment 3 of the HI-STAR 100 Storage System CoC, updating the scoping and AMR tables accordingly. These SSCs include, but may not necessarily be limited to:

• MPC Vent and Drain Tube, Optional

• MPC Threaded Disc, Plug Adjustment

• MPC Vent and Drain Plug

• MPC Thread Shield Cap

• MPC Retaining Ring

2. Update Table 1.3-1 of the renewal application to reference the revision of HI-2012610, the HI-STAR 100 FSAR, that defines the design bases for CoC Amendment No. 3.

Table 1.3-1 of the renewal application lists the FSAR revisions that apply to each amendment of the CoC. However, that table does not include a reference to the FSAR revision that serves as the design-basis FSAR for CoC Amendment No. 3.

This information is needed to confirm compliance with 10 CFR 72.240(c).

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Chapter 3: Aging Management Review RAI 3-3 If the thermal expansion foam is in the scope of renewal (based on the response to RAI 2-3 and RAI 2-4 Follow-up), provide the technical basis that supports the conclusion that the foam does not have any credible aging effects due to radiation exposure that could challenge an important-to-safety function in the period of extended operation.

The silicone thermal expansion foam in the HI-STAR 100 Overpack is identified as a not-important-to-safety (NITS) item in the renewal application scoping tables. However, the foam was included in the scope of the aging management review in Chapter 3 of the renewal application, although the application did not identify the basis for including it within scope.

Further, the application concluded that the foam does not have any aging effects requiring management. If the thermal expansion foam is considered to be in the scope of renewal (based on the response to RAI 2-4a), clarify the bases for the results of the scoping and aging management review, as follows:

1. Clarify how an important-to-safety function is affected by potential degradation of the thermal expansion foam. HI-STAR 100 FSAR Section 1.2.1.2 states that the foam may be required to alleviate thermal stresses from differential thermal expansion. It is not clear to the staff how a change in the foam properties may prevent it from fulfilling that role (i.e., how an important-to-safety function is (or is not) impacted if the thermal stresses are not alleviated).

2. Provide the technical basis for the conclusion that the gamma and neutron exposure throughout the period of extended operation will not challenge the structural integrity function of the foam. As described in NUREG-2214 Section 3.3.1.3, radiation can embrittle polymeric materials, and studies on the effects of gamma and neutron radiation on silicone foams have observed a loss of ductility (Liu, 2017). HI-STAR 100 FSAR Appendix 1.C states that silicone is highly resistant to the radiation exposure levels present in the storage system; however, no support for that statement was provided.

This information is needed to confirm compliance with 10 CFR 72.240(c).

Reference B. Lie, et al., Effects of Combined Neutron and Gamma Irradiation Upon Silicone Foam, Radiation Physics and Chemistry, Vol. 133, pp. 31-36, 2017.

Appendix D: Aging Management FSAR Changes RAI D-1 Follow-up Provide the updated proposed changes to the HI-STAR 100 FSAR in Appendix D of the renewal application (FSAR supplement), including any referenced tables, as revised through the response to this request for clarification, and to incorporate the following clarifications.

Update the FSAR supplement to clarify the following renewal application references:

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• Table 9.2.3 of the FSAR supplement (Independent Spent Fuel Storage Installation (ISFSI) Pad AMP) references Table 3.3.5, which is likely a reference to Table 3.3-5 (with hyphen) of the renewal application that contains the AMR table for the ISFSI pad.

• When incorporating by reference the renewal application Tables 3.3-3 and 3.3-5 in the proposed FSAR Tables 9.2.2 and 9.2.3, respectively, provide a clear reference to the specific revision of the renewal application (e.g., Table 3.3-3 of Revision 1C of the HI-STAR 100 CoC Renewal Application).

Clarify these references or fully incorporate the final AMR tables into the FSAR supplement to ensure that the aging management activities are appropriately included in the FSARs for each renewed CoC amendment.

In addition, in Table 3.3-3 of the renewal application, which is referenced in the FSAR supplement, the staff noted an editorial error where the Embedded (in concrete) environment for the overpack bottom plate was placed under the Aging Effects Requiring Management column. Revise the table to clarify the aging effects being managed by the Overpack AMP for this line item.

Appendix D of the renewal application provides the proposed FSAR supplement to document the aging management information associated with the CoC renewal, per 10 CFR 72.240(c).

The CoC renewal will include a condition for the CoC holder to update the FSAR to reflect the changes and commitments resulting from the review and approval of the CoC renewal. The FSAR must clearly reflect the approved design bases, including aging management information in the period of extended operation if the renewal is approved. Therefore, the FSAR supplement in Appendix D of the renewal application must include all FSAR changes related to the renewal of the CoC.

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

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