ML22193A087

Letter RAI Set 3 (Final)

ML22193A087
Person / Time
Site:	Saint Lucie
Issue date:	07/11/2022
From:	Harris B NRC/NRR/DNRL/NLRP
To:	Coffey R Florida Power & Light Co
Harris B
Shared Package
ML22193A085	List: ML22193A086 ML22193A087
References
Download: ML22193A087 (7)

Text

ST. LUCIE NUCLEAR PLANT, UNITS 1 AND 2 SUBSEQUENT LICENSE RENEWAL APPLICATION (SLRA)

REQUESTS FOR ADDITIONAL INFORMATION (SET #3)

SAFETY REVIEW RAI 4.2-1 Regulatory Basis 10 CFR § 54.21(c) requires the applicant to evaluate time limited aging analyses (TLAA) and disposition them in accordance with (c)(1)(i), (c)(1)(ii), or (c)(1)(iii). 10 CFR § 54.21(d) requires that the FSAR supplement for the facility must contain a summary description of the programs and activities for managing the effects of aging and evaluation of the TLAA for the period of extended operation determined by 54.21(a) and 54.21(c).

Background

SLRA Tables 4.2.2-1 and 4.2.3-1 provide the unirradiated RTNDT and upper-shelf energy (USE) values, respectively, for the Unit 1 RPV materials at 72 effective full power years (EFPY). The footnotes for SLRA Tables 4.2.2-1 and 4.2.3-1 indicate that Westinghouse report WCAP-18609-NP, Revision 2 (herein after referred to as WCAP-18609-NP), is the source document for these unirradiated values.

Table 3-1 of WCAP-18609-NP indicates the following for the Upper to Intermediate Shell Girth Weld Seam 8-203 (Heat Number 21935):

• Footnote (g) - USE for Heat # 21935 is from Diablo Canyon 1 (WCAP-17315-NP, Intermediate to Lower Shell Weld Seam 9-442. Both materials were made with Heat

1. 21935 and Linde 1092 flux).

Table 3-1 of WCAP-18609-NP indicates the following for the Upper Shell Axial Weld Seams 1-203 A, B, and C (Heat Number 21935/12008):

• Footnote (h) - RTNDT(U) for Heat # 21935/12008, Linde 1092, Lot 3869 is from identical material at Diablo Canyon 2 (WCAP-17315-NP).

• Footnote (i) - USE for Heat # 21935/12008, Linde 1092, Lot 3869 is from identical material at Diablo Canyon 2 (WCAP-17315-NP), specifically Intermediate Shell Axial Welds 2-201 A/B/C.

Issue The staff noted the following was not provided in Section 4.2 of the SLRA:

• The applicant did not provide an adequate justification demonstrating that the unirradiated USE value from Diablo Canyon, Unit 1 (as referenced in footnote (g) of Table 3-1 of WCAP-18609-NP) is conservative, representative, or applicable for use as

the unirradiated USE value for the upper to intermediate shell girth weld seam 8-203 at St. Lucie, Unit 1.

• The applicant did not provide an adequate justification demonstrating that the unirradiated USE value from Diablo Canyon, Unit 2 (as referenced in footnote (i) of Table 3-1 of WCAP-18609-NP) is conservative, representative, or applicable for use as the unirradiated USE value for the upper shell axial weld seams 1-203 A, B, and C in St.

Lucie, Unit 1.

• The applicant did not provide an adequate justification demonstrating that the unirradiated RTNDT value from Diablo Canyon, Unit 2 (as referenced in footnote (h) of Table 3-1 of WCAP-18609-NP) is conservative, representative, or applicable for use as the unirradiated RTNDT value for the upper shell axial weld seams 1-203 A, B, and C in St. Lucie, Unit 1.

The staff noted that inherent characteristics of manufacturing the RPV such as, but not limited to, welding processes, procedures and qualifications, post weld heat treatment activities, manufacturer/fabricator, and time of fabrication, have the potential to impact the unirradiated values for USE and RTNDT for RPV materials from plant to plant.

Additionally, the applicant did not describe how Diablo Canyon determined these initial values of USE and RTNDT, and whether this information supports the applicants determination that these initial values are conservative, appropriate, or applicable for use at St Lucie, Unit 1.

Request

1. Describe and justify the process the applicant went through for assessing how Diablo Canyon obtained the above referenced values.

2. Taking into consideration the inherent characteristics that could affect the unirradiated USE and RTNDT values, as described above, justify how the methods, processes, or analysis used by Diablo Canyon to obtain or develop these values are conservative, representative, or applicable to use for St. Lucie, Unit 1 RPV materials.

RAI 3.3.2.2.9-1 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 in regard to the matters described below.

Background

As amended by letter dated April 7, 2022 (ML22097A202), the Subsequent License Renewal Application (SLRA) cites no aging effects requiring management for the following auxiliary system steel components exposed to an external environment of concrete: (a) piping and ducting in the ventilation system; and (b) the Unit 2 diesel oil storage tanks (DOSTs). These components cite Standard Review Plan for Subsequent License Renewal (SRP-SLR) item 3.3.1-112, which is associated with the further evaluation in SRP-SLR Section 3.3.2.2.9.

SRP-SLR Section 3.3.2.2.9 states the following:

If the following conditions are met, loss of material is not considered to be an applicable aging effect for steel [exposed to concrete]: (a) attributes of the concrete are consistent with American Concrete Institute (ACI) 318 or ACI 349 (low water-to-cement ratio, low permeability, and adequate air entrainment) as cited in NUREG-1557; (b) plant-specific OE [operating experience] indicates no degradation of the concrete that could lead to penetration of water to the metal surface; and (c) the piping is not potentially exposed to groundwater.

SLRA Section 3.3.2.2.9 states [a] review of OE for PSL indicates there are occurrences of concrete degradation, in some systems, that could lead to the penetration of water to the metal surface; therefore, a loss of material due to general, pitting, and crevice corrosion of steel piping and tanks exposed to concrete is an aging effect that requires management. In addition, SLRA Section 3.3.2.2.9 does not state whether attributes of the concrete for piping and ducting in the ventilation system are consistent with ACI 318 or ACI 349.

By letter dated April 7, 2022, the applicant stated the following:

unlike the Unit 1 DOSTs, the Unit 2 DOSTs 2A and 2B are excluded from the scope of the Outdoor and Large Atmospheric Metallic Storage Tanks AMP for SLR, since the Unit 2 DOSTs are indoors (within the Unit 2 DOST building) with a capacity of less than 100,000 gallons and no history of moisture at the inaccessible exterior bottom surface

[emphasis added by staff].

During its audit, the staff reviewed plant-specific operating experience where visual inspections of the external surfaces of the Unit 2 DOSTs revealed minor surface corrosion. In addition, during a walkdown of the 2A DOST, the staff noted that caulking at the interface of the tank bottom and concrete was damaged.

Issue For piping and ducting in the ventilation system, the staff seeks clarification with respect to how SRP-SLR Section 3.3.2.2.9 criteria are met, given that there have been occurrences of concrete degradation that could lead to the penetration of water to the metal surface. In addition, SLRA Section 3.3.2.2.9 does not address whether attributes of the concrete are consistent with ACI 318 or ACI 349 (associated with SRP-SLR Section 3.3.2.2.9 criterion (a)).

For the Unit 2 DOSTs, the staff seeks clarification with respect to citing no aging effects for the tank-to-concrete interface. The April 7, 2022, submittal states there is no history of moisture at the inaccessible exterior bottom surface. However, it is unclear to the staff how moisture can be readily identified at an inaccessible location. In addition, the staff notes there is plant-specific operating experience involving (a) minor corrosion on accessible external surfaces of these tanks; and (b) damaged caulking at the tank-to-concrete interface. Based on these

observations, it is unclear to the staff why corrosion could also not occur at the tank-to-concrete interface.

Request Provide additional clarification with respect to citing no aging effects for the following auxiliary system steel components exposed to an external environment of concrete: (a) piping and ducting in the ventilation system; and (b) the Unit 2 DOSTs.

RAI 3.4.2.2.8-1 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 in regard to the matters described below.

Background

The subsequent License Renewal Application (SLRA) cites no aging effects requiring management for the Unit 2 steel condensate storage tank (CST) exposed to an external environment of concrete. This component cites Standard SRP-SLR item 3.4.1-51, which is associated with the further evaluation in SRP-SLR Section 3.4.2.2.8.

SRP-SLR Section 3.4.2.2.8 states the following:

If the following conditions are met, loss of material is not considered to be an applicable aging effect for steel [exposed to concrete]: (a) attributes of the concrete are consistent with American Concrete Institute (ACI) 318 or ACI 349 (low water-to-cement ratio, low permeability, and adequate air entrainment) as cited in NUREG-1557; (b) plant-specific OE indicates no degradation of the concrete that could lead to penetration of water to the metal surface; and (c) the piping is not potentially exposed to groundwater.

SLRA Section 3.4.2.2.8 states the following in part:

• [t]he carbon steel condensate storage tank bottoms sit on a concrete pad. There is no OE indicating degradation of the concrete that could lead to penetration of water to the metal surface, and the tanks are not exposed to groundwater.

• [t]he Unit 2 CST and associated piping and components are located in a separate CST building, a structural missile barrier, which provides protection from weather. Therefore, loss of material of steel exposed to concrete for the Unit 2 CST is not an applicable aging effect but is an applicable aging effect for the Unit 1 CST.

Issue The staff seeks clarification with respect to citing no aging effects for the Unit 2 CST surfaces exposed to an external environment of concrete. Although the structural missile barrier can protect the Unit 2 CST from weather, it is unclear how this can prevent moisture accumulation at the tank-to-concrete interface.

Request:

Provide additional clarification with respect to citing no aging effects for the Unit 2 CST surfaces exposed to an external environment of concrete.

RAI 3.6.1.1-1 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 in regard to the matters described below.

Background

Subsequent License Renewal Application (SLRA), Supplement 1, Section 2.5.1.3, Elimination of Electrical and I&C Commodity Groups Not Applicable to St. Lucie, and Section 3.6.1.1, Electrical Commodity Groups Not Requiring Aging Management, addressed the aging management review (AMR) of new fuse holders (not part of active equipment) for aging effects consistent with the screening guidance in NUREG-2191 (GALL- SLR Report),Section XI.E5.

The applicant states:

This fuse box is located in a controlled (benign) environment, the fuses are not manipulated, and the fuses are not subject to electrical stress (high cycling or high heating). There are no relevant aging mechanisms or aging effects for these fuse holders, relative to the insulating material, the metallic clamps, or the fuse box itself (i.e.,

there are no stressors to cause corrosion or age-related degradation). These fuse holders are within the scope of SLR, but because they do not have relevant aging mechanisms and are not manipulated and are not subject to aging effects, they do not require aging management, consistent with the guidance of NUREG-2191,Section XI.E5.

The subject fuse holders are located in a junction box in a benign environment, are not exposed to environmental stressors (thermal or radiation or moisture), and do not experience electrical stress (high voltage or high cycling). The fuse holders therefore do not warrant aging management, and do not require an aging management program at PSL.

SLRA, Revision 1, Supplement 1, Table 3.6.2-1, Electrical and Instrumentation & Control Commodities - Summary of Aging Management Evaluation, and SLRA, Revision 1, Table 3.6-

1, Summary of Aging Management Evaluation for Electrical and Instrumentation & Control Commodities, provided the aging management evaluations for the in-scope fuse holders in accordance with the aging effects/mechanisms listed in NUREG-2191, Chapter VI, Table A, Equipment Not Subject to 10 CFR 50.49, Environmental Qualification Requirements, for AMP XI.E5.

Issue NUREG-2191, Chapter VI, Electrical Components, Table A, Equipment Not Subject to 10 CFR 50.49 Environmental Qualification Requirements, AMP XI.E5, identifies the following aging effects/mechanisms that can affect fuse holders (not part of active equipment):

• The metallic clamps of fuse holders can be subject to increased electrical resistance of connection due to chemical contamination, corrosion, and oxidation or fatigue caused by ohmic heating, thermal cycling, electrical transients, frequent removal /manipulation or vibration.

• The electrical insulation materials of fuse holders can be subject to reduced insulation resistance due to thermal/thermoxidative degradation of organics, radiolysis and photolysis (UV sensitive materials only) of organics, radiation-induced oxidation, and moisture intrusion.

NUREG-2192 Table 3.6-1, Summary of Aging Management Programs for the Electrical Components Evaluated in Chapter VI of the GALL-SLR Report, stated that no AMP is required for the fuse holders if the applicant can demonstrate that these fuse holders are not subject to the aging effects/mechanisms identified in the Table 3.6-1 and in NUREG-2191, Table A, AMP XI.E5.

The staff notes that the applicant did not demonstrate how they came to the conclusion that the fuse holders are not subject to the stressors that cause the aging effects/mechanisms provided in the NUREG-2191, Table A, AMP XI.E5, as recommended in NUREG-2192.

Request Provide a summary of the evaluation used to demonstrate how the applicant determined that the fuse holders electrical metallic clamps and insulation materials are not subject to the above-mentioned stressors (i.e., thermal, radiation, moisture, ohmic heating, thermal cycling, electrical transients, vibration, frequent removal/manipulation, chemical contaminants, thermal/

thermoxidative degradation of organics, radiolysis and photolysis of organics, etc.) as they relate to the above-mentioned aging effects/mechanisms listed in NUREG-2191, Table A, AMP XI.E5, found to be acceptable for adequately managing the effects of aging during the period of extended operation.

RAI 19.2.2.17-2 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 in regard to the matters described below.

Background

10 CFR 54.21(d) requires each license renewal application to include a final safety analysis report (FSAR) supplement, containing a summary description of the programs and activities for managing the effects of aging. In its discussions about FSAR supplements, the Standard Review Plan for Subsequent License Renewal (NUREG-2192) notes that the description should be sufficiently comprehensive such that later changes to the program can be controlled by 10 CFR 50.59. NUREG-2192 also notes that the Generic Aging Lessons Learned for Subsequent License Renewal (GALL-SLR) Report (NUREG-2191), Table XI-01 provides examples of the type of information to be included. GALL-SLR Report Table XI-01, FSAR Supplement Summaries for GALL-SLR Report Chapter XI Aging Management Programs [AMP], provides a description of the Outdoor and Large Atmospheric Metallic Storage Tanks program (AMP XI.M29), stating that loss of material is managed by conducting periodic internal and external visual examinations.

Issue The Updated Final Safety Analysis Report (UFSAR) supplement for the Outdoor and Large Atmospheric Metallic Storage Tanks program appears to lack sufficient details for inspecting the Unit 1 Refueling Water Tank (U1 RWT). The staff questions whether the inspection frequency and technique will be based on the NRC approved ASME Section XI Inservice Inspection relief request.

Request Regarding SLRA Section 19.2.2.17, either: a) provide additional information that explains how the current description of the program and aging management activities in the UFSAR supplement meets the intent of 10 CFR 54.21(d) and NUREG-2192, which states that the description should be sufficiently comprehensive such that later changes to the program can be controlled by 10 CFR 50.59 or b) modify the UFSAR supplement to include information related to the U1 RWT and ASME Section XI Inservice Inspection relief request.