ML23256A150
| ML23256A150 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 09/11/2023 |
| From: | Mark Yoo NRC/NRR/DNRL/NLRP |
| To: | Peters K Comanche Peak Nuclear Power Co |
| References | |
| Download: ML23256A150 (1) | |
Text
REQUEST FOR ADDITIONAL INFORMATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION COMANCHE PEAK UNITS 1 & 2 LICENSE RENEWAL APPLICATION REVIEW VISTRA OPERATIONS COMPANY LLC COMANCHE PEAK, UNITS 1, 2 DOCKET NO. 05000445, 05000446 ISSUE DATE: 9/11/2023
Set 4
RAI B.2.3.16-4a
Regulatory Basis:
Section 54.21(a)(3) of Title 10 of the Code of Federal Regulations (10 CFR) requires an applicant to demonstrate that the effects of aging for structures and components will be adequately managed so that the intended function(s) will be maintained consistent with the current licensing basis for the period of extended operation. One of the findings that the U.S.
Nuclear Regulatory Commission (NRC) staff must make to issue a renewed license (10 CFR 54.29(a)) is that actions have been identified and have been or will be taken with respect to managing the effects of aging during the period of extended operation on the functionality of structures and components that have been identified to require review under 10 CFR 54.21, such that there is reasonable assurance that the activities authorized by the renewed license will continue to be conducted in accordance with the current licensing basis. In order to complete its review and enable making a finding under 10 CFR 54.29(a), the staff requires additional information as described in the requests for additional information.
Background:
By letter dated July 27, 2023, in response (Agencywide Documents Access and Management System (ADAMS) Accession No. ML23208A193) to Request for Additional Information (RAI)
B.2.3.16-4, the applicant revised the table entitled Fire Water System Inspections and Tests in Section B.2.3.16 of Appendix B in the License Renewal Application (LRA) that provides additional detail on the required enhancements based on Table 4a, Fire Water System Inspection and Testing Recommendations, in Appendix L, Revised GALL Report AMP XI.M27 Fire Water System, of License Renewal Interim Staff Guidance, LR-ISG-2012- 02, Aging Management of Internal Surfaces, Fire Water Systems, Atmospheric Storage Tanks, and Corrosion Under Insulation (ML13227A361). Specifically, the table in Section B.2.3.16 of LRA Appendix B that provides additional detail on the required enhancements based on Table 4a in Appendix L of LR-ISG-2012- 02 (Operational Tests, NFPA 25 Section 10.3.4.3) was revised to clarify which deluge system operational tests are performed with water, to clarify which deluge systems are tested with air instead of water, and to add an enhancement related to monitoring and trending the results of the deluge system operational tests performed with water (i.e., pump performance, run and discharge time, pressure, deposits or sediment).
Section B.2.3.16 in LRA Appendix B includes a table that provides additional detail on the required enhancements based on Table 4a in Appendix L of LR-ISG-2012-02. However, the associated enhancement to the Detection of Aging Effects, Monitoring and Trending, and Acceptance Criteria program elements in Table A-3, List of LR Commitments and Implementation Schedule, in LRA Appendix A (No. 18) does not refer to the table for additional detail on the required enhancements.
1 It is unclear why some enhancements are identified as an enhancement to a particular program element in Table A-3 in LRA Appendix A and Section B.2.3.16 in LRA Appendix B while other required enhancements are identified in the table that provides additional detail on the required enhancements based on Table 4a in Appendix L of LR-ISG-2012- 02 in Section B.2.3.16 in LRA Appendix B.
Issue:
Because the table in Section B.2.3.16 of LRA Appendix B that provides additional detail on the required enhancements based on Table 4a in Appendix L of LR-ISG-2012-02 is not referenced in the associated enhancement to the Detection of Aging Effects, Monitoring and Trending, and Acceptance Criteria program elements in Table A-3 in LRA Appendix A, it may be hard to verify implementation of all of the required enhancements.
Request:
Please discuss why some enhancements are identified as an enhancement to a particular program element in Table A-3 in LRA Appendix A and Section B.2.3.16 in LRA Appendix B while other required enhancements are identified in the table that provides additional detail on the required enhancements based on Table 4a in Appendix L of LR-ISG-2012-02 in Section B.2.3.16 in LRA Appendix B. Alternatively, revise the associated enhancement to the Detection of Aging Effects, Monitoring and Trending, and Acceptance Criteria program elements in Table A-3 in LRA Appendix A to clearly reference the table that provides additional detail on the required enhancements.
RAI B.2.3.15-3
Regulatory Basis:
Section 54.21(a)(3) of Title 10 of the Code of Federal Regulations (10 CFR) requires an applicant to demonstrate that the effects of aging for structures and components will be adequately managed so that the intended function(s) will be maintained consistent with the current licensing basis for the period of extended operation. One of the findings that the U.S.
Nuclear Regulatory Commission (NRC) staff must make to issue a renewed license (10 CFR 54.29(a)) is that actions have been identified and have been or will be taken with respect to managing the effects of aging during the period of extended operation on the functionality of structures and components that have been identified to require review under 10 CFR 54.21, such that there is reasonable assurance that the activities authorized by the renewed license will continue to be conducted in accordance with the current licensing basis. In order to complete its review and enable making a finding under 10 CFR 54.29(a), the staff requires additional information as described in the requests for additional information.
Background:
As amended by letter dated April 24, 2023 (ML23114A377), License Renewal Application (LRA)
Table 3.5.2-15 states that loss of material of ceramic fiber/blanket insulation and wrap exposed to indoor uncontrolled air and cracking, loss of bond, and loss of material of gypsum walls, floors, and ceilings exposed to indoor uncontrolled air are managed by the Fire Protection program. The items cite plant-specific notes 2 and 4, which state, This material is not addressed for fire barriers in NUREG-1801. Consistent with the OE [operating experience]
reflected in SLR-ISG-2021- 02-MECHANICAL (items VII.G.A-805 to VII.G.A-807; SRP items 3.3-1, 267 to 3.3-1, 269), aging of the component materials is managed by the Fire Protection (B.2.3.15) AMP, and Gypsum drywall is utilized throughout the plant to provide a fire barrier which is lightweight and where unit masonry or concrete is not feasible. This lightweight fire
2 barrier material is not addressed in NUREG-1801; however, aging is managed by the Fire Protection (B.2.3.15) AMP, respectively.
Subsequent License Renewal (SLR) Interim Staff Guidance (ISG), SLR-ISG-2021 Mechanical, Updated Aging Management Criteria for Mechanical Portions of Subsequent License Renewal Guidance (ML20181A434), added Aging Management Review Items VII.G.A-805, VII.G.A-806, and VII.G.A-807 to Table VII.G in Volume 1 of NUREG-2191, Generic Aging Lessons Learned for Subsequent License Renewal (GALL-SLR) Report (ML17187A031), and Table 3.3-1 in NUREG-2192, Standard Review Plan [SRP] for Review of Subsequent License Renewal Applications for Nuclear Power Plants (ML17188A158). The aging effects for cementitious coatings, silicates, and subliming compounds used as fireproofing/fire barriers exposed to air are loss of material, change in material properties, cracking, delamination, and separation. These aging effects are consistent with Section 6, Fire Barriers, of EPRI 3002013084, Long-Term Operations: Subsequent License Renewal Aging Affects for Structures and Structural Components (Structural Tools), November 2018.
Issue:
While LRA Table 3.5.2-15 states that ceramic fiber/blanket insulation and wrap is consistent with the OE in SLR-ISG-2021 MECHANICAL (items VII.G.A-805 to VII.G.A-807; SRP items 3.3-1, 267 to 3.3-1, 269), it does not cite change in material properties, cracking, delamination, and separation as applicable aging effects. It is unclear why these aging effects were not cited as applicable for ceramic fiber/blanket insulation and wrap since LRA Table 3.5.2015 states it is consistent with the OE in SLR-ISG-2021 MECHANICAL and given that these materials are similar to silicate fireproofing/fire barriers.
LRA Table 3.5.2-15 does not cite change in material properties, delamination, and separation as applicable aging effects for gypsum walls, floors, and ceilings; and does cite loss of bond as an applicable aging effect. It is unclear why change in material properties, delamination, and separation were not cited as applicable aging effects for gypsum walls, floors, and ceilings given that gypsum is similar to silicate fireproofing/fire barriers.
Request:
- 1. Please discuss why change in material properties, cracking, delamination, and separation were not cited as applicable aging effects for the ceramic fiber/blanket insulation and wrap.
Alternatively, revise LRA Table 3.5.2-15 to cite these aging effects for the ceramic fiber/blanket insulation and wrap. If change in material properties, cracking, delamination, and separation are added as applicable aging effects for the ceramic fiber/blanket insulation and wrap, please discuss whether plant-specific procedures require updating to address these aging effects.
- 2. Please discuss why change in material properties, delamination, and separation were not cited as applicable aging effects for the gypsum walls, floors, and ceilings. Alternatively, revise LRA Table 3.5.2-15 to cite these aging effects for the gypsum walls, floors, and ceilings. If change in material properties, delamination, and separation are added as applicable aging effects for the gypsum walls, floors, and ceilings, please discuss whether plant-specific procedures require updating to address these aging effects. The staff notes, that if LRA Table 3.5.2-15 is revised to cite these aging effects, then plant-specific note 2 may be applicable to the gypsum walls, floors, and ceilings.
3 RAI 3.2.2.2.3.2-1a
Regulatory
Background:
10 CFR 54.21(a)(3) requires an applicant to demonstrate that the effects of aging for structures and components will be adequately managed so that the intended function(s) will be maintained consistent with the current licensing basis for the period of extended operation. One of the findings that the staff must make to issue a renewed license (10 CFR 54.29(a)) is that actions have been identified and have been or will be taken with respect to managing the effects of aging during the period of extended operation on the functionality of structures and components that have been identified to require review under 10 CFR 54.21, such that there is reasonable assurance that the activities authorized by the renewed license will continue to be conducted in accordance with the current licensing basis. In order to complete its review and enable making a finding under 10 CFR 54.29(a), the staff requires additional information about the matter described in the Request for Additional Information.
Background:
By letter dated July 27, 2023 (ML23208A193), Attachment E, in response to Request for Additional Information 3.2.2.2.3.2-1, the applicant clarified its aging management approach and revised the License Renewal Application (LRA) regarding loss of material (LOM) and stress corrosion cracking (SCC) of stainless steel components exposed to outdoor air in the Engineered Safety Features, Auxiliary, and Steam and Power Conversion systems. The associated LRA sections are 3.2.2.2.3.2, 3.2.2.2.6, 3.3.2.2.3, 3.3.2.2.5, 3.4.2.2.2, and 3.4.2.2.3.
Issue:
The RAI response provided a discussion of managing LOM (due to pitting or crevice corrosion) and SCC of stainless steel in outdoor air considering differences between the guidance for initial license renewal (Reference 1) and subsequent license renewal (Reference 2). As part of the response, the applicant revised LRA Tables 3.3.2-4, 3.4-1, and 3.4.2-1. The response also discussed the basis for not identifying SCC as an applicable aging effect for stainless steel exposed to outdoor air. It is not clear to the staff why some of the LRA revisions are for carbon steel components. In addition, the criteria applied to stainless steel components and the revisions to the LRA for stainless steel components are unclear to the staff. Finally, the staff determined that the basis for not identifying SCC as an applicable aging effect may not take into account the operating experience used to develop SLR guidance and requires additional technical justification.
Request:
- 1. Changes to the LRA in the RAI response include the deletion of carbon steel components from Tables 3.3.2-4 (Demineralized and Reactor Makeup Water System) and 3.4.2-1 (Auxiliary Feedwater System). Please provide the basis for deleting these items from the tables.
- 2. The first paragraph of the response to Question 1 states that components located within piping tunnels were removed from consideration for pitting and crevice corrosion. Please clarify the aging management treatment for the components in piping tunnels. The staff notes that the GALL-SLR Report (Reference 3),Section XI.M36 states that for underground piping below grade but within a tunnel, aging effects can be managed by the External Surfaces Monitoring of Mechanical Components AMP or the Buried and Underground Piping and Tanks AMP, depending on accessibility.
- 3. If stainless steel components shown deleted from Tables 3.3.2-4 and 3.4.2-1 were deleted for reasons other than being located in piping tunnels, please provide the justification.
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- 4. Part a of the response to Question 1 notes that aging effects are not considered for stainless steel flow elements and orifices exposed to outdoor air in the Fire Protection System. These components are associated with Note I and Footnote 5 in Table 3.3.2-7.
The footnote refers to LRA Section 3.3.2.2.6 for the justification. However, the staff did not find a justification for this topic in Section 3.3.2.2.6, Quality Assurance for Aging Management of Nonsafety-Related Components, or in Sections 3.3.2.2.3 or 3.3.2.2.5 related to LOM and SCC for stainless steel. If another section was intended, please identify the section and provide the justification.
- 5. The response to Question 2 provides a basis for not considering SCC, including cases where LOM due to pitting or crevice corrosion is considered. The response cites a lack of ambient environmental halides, lack of OE identifying past instances of LOM or SCC for stainless steel in outdoor air at CPNPP, and absence of elevated temperature for the subject components. However, operating experience includes examples of chloride-induced SCC of austenitic stainless steel occurring at about 100 degrees Fahrenheit or less (References 4 and 5). In addition, in the SLR guidance, the ambient contaminant level and lack of operating experience are no longer considered sufficient for determining the susceptibility because of the potential for unexpected sources of contaminants and concentrating effects. Elevated temperature is not used as a criterion in NUREG-1800 Sections 3.2.2.2.6, 3.3.2.2.3, 3.4.2.2.2 (Referen ce 1), or corresponding SRP-SLR Sections 3.2.2.2.4, 3.3.2.2.3, 3.4.2.2.2 (Reference 2).
Please clarify whether and how the operating experience in References 4 and 5 was considered. Specifically, the staff requests additional justification for not applying aging management for SCC comparable to that for LOM due to pitting or crevice corrosion (i.e.,
External Surfaces Monitoring of Mechanical Components AMP).
- 6. Please clarify part f of the response to Question 1, which states that the recommended one-time inspection in SLR guidance was found to be not applicable for initial license renewal. The staff requests clarification because part a of the response identifies specific components for which LOM was not identified as an applicable aging effect, and part b of the response describes components that are addressed with the External Surfaces Monitoring of Mechanical Components AMP. Please clarify whether part f of the response refers to stainless steel components other than those noted in part a for which LOM due to pitting or crevice corrosion was not identified as an applicable aging effect.
References:
- 1. NUREG-1800, Revision 2, Standard Review Plan for Review of License Renewal Applications for Nuclear Power Plants, December 2010, ML103490036.
- 2. NUREG-2192, Standard Review Plan for Review of Subsequent License Renewal Applications for Nuclear Power Plants, July 2017, ML17188A158
- 3. NUREG-2191, Vol. 2, Generic Aging Lessons Learned for subsequent License Renewal (GALL-SLR) Report, July 2017, ML17187A294
- 4. Information Notice 2012-20, Potential Chloride-Induced Stress Corrosion Cracking of Austenitic Stainless Steel and Maintenance of Dry Cask Storage System Canisters, 11/14/2012, ML12319A440.
- 5. Licensee Event Report 254-2006- 004, Through -wall Leak in Standby Liquid Control Tank Due to the Original Construction Use of Grout with Leachable Halogens, 12/11/2006, ML063530355.
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