ML18157A260

Supplemental Information to Support Application to Adopt 10 CFR 50.69, Risk-Informed Categorization and Treatment of Structures, Systems, and Components for Nuclear Power Plants.

ML18157A260
Person / Time
Site:	Peach Bottom
Issue date:	06/06/2018
From:	Jim Barstow Exelon Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
Download: ML18157A260 (16)

Text

Exelon Generation ~ 200 Exelon Way Kennett Square. PA 19348 www.exeloncorp.com 10 CFR 50.90 June 6, 2018 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Peach Bottom Atomic Power Station, Units 2 and 3 Renewed Facility Operating License Nos. DPR-44 and DPR-56 NRC Docket Nos. 50-277 and 50-278

Subject:

Supplemental Information to Support Application to Adopt 10 CFR 50.69, "Risk-informed categorization and treatment of structures, systems, and components for nuclear power plants"

References:

1. Letter from James Barstow (Exelon Generation Company, LLC) to U.S. Nuclear Regulatory Commission - "Application to Adopt 10 CFR 50.69, 'Risk-informed categorization and treatment of structures, systems, and components for nuclear power plants,"' dated August 30, 2017 (ML17243A014)

2. Letter from Richard B. Ennis (U.S. Nuclear Regulatory Commission) to Bryan C.

Hanson, Exelon Generation Company, LLC- "Supplemental Information Needed for Acceptance of Requested Licensing Action Re: Adoption of title 1O of the Code of Federal Regulations Section 50.69," dated October 10, 2017 (ML17272B016)

3. Letter from James Barstow (Exelon Generation Company, LLC) to U.S. Nuclear Regulatory Commission - "Supplement to Application to Adopt 10 CFR 50.69, Risk-Informed Categorization and Treatment of Structures, Systems, and Components for Nuclear Power Reactors," dated October 24, 2017(ML17297B521)

4. Electronic mail message from Jennifer Tobin (U.S. Nuclear Regulatory Commission) to David Helker, Exelon Generation Company, LLC - "Draft 50.69 Request for Additional Information (RAls) - Peach Bottom," dated March 21, 2018

5. Electronic mail message from Jennifer Tobin (U.S. Nuclear Regulatory Commission) to David Helker, Exelon Generation Company, LLC - "Peach Bottom Units 2 and 3 -

Request for Additional Information - Adopt 50.69 License Amendment," dated April 6, 2018

6. Letter from James Barstow (Exelon Generation Company, LLC) to U.S. Nuclear Regulatory Commission - "Response to Request for Additional Information Application to Adopt 10 CFR 50.69, "Risk-informed categorization and treatment of structures, systems, and components for nuclear power plants," dated May 7, 2018 (ML18128A009)

U.S. Nuclear Regulatory Commission Supplemental Response Application to Adopt 10 CFR 50.69 Docket Nos. 50-277 and 50-278 June 6, 2018 Page 2 By letter dated August 30, 2017 (Reference 1), Exelon Generation Company, LLC (Exelon) requested an amendment to the Renewed Facility Operating License (RFOL) Nos. DPR-44 and DPR-56 for Peach Bottom Atomic Power Station (PBAPS), Units 2 and 3, respectively.

The proposed amendment would modify the licensing basis by the addition of a license condition to allow for the implementation of the provisions of Title 1O of the Code of Federal Regulations (10 CFR), Part 50.69, "Risk-informed categorization and treatment of structures, systems, and components for nuclear power reactors." In a letter dated October 10, 2017 (Reference 2}, the U.S. Nuclear Regulatory Commission (NRC) requested that Exelon provide supplemental information in support of the application. By letter dated October 24, 2017 (Reference 3), Exelon responded to the NRC's request for supplemental information.

The NRC reviewed the information provided in the Reference 1 and 3 submittals and indicated the need for additional information in order to complete their review and evaluation of the amendment request. In an electronic mail message dated March 21, 2018 (Reference 4), the NRC issued a draft Request for Additional Information (RAI). This draft RAl was the subject of further discussions during a teleconference on April 6, 2018, between Exelon and NRC representatives, and additional clarification was provided. The NRC then issued the formal RAI (Reference 5) in which they requested a response by May 7, 2018. With the exception of Question 1O.c, Exelon responded to all other questions in the RAI by letter dated May 7, 2018 (Reference 6).

The request to defer submitting specific information in response to Question 1O.c was discussed with the NRC Project Manager for PBAPS, and a due date of June 6, 2018, was agreed upon for the response to Question 10.c. As indicated in the Reference 6 letter, Exelon noted that additional time was needed in order to fully respond to NRC RAI Question 1O.c in support of the station's continuing efforts to assess tornado missile protection hazards in response to RlS 2015-06, "Tornado Missile Protection," (ML15020A419).

Accordingly, Attachment 1 to this letter provides Exelon's response to NRC RAI Question 1O.c. Attachment 2 of this letter contains an updated table listing the 10 CFR 50.69 Probabilistic Risk Assessment (PRA) implementation items, which supersedes the previous list contained in Attachment 2 in the Reference 5 submittal. Attachment 3 contains updated proposed mark-up pages for the PBAPS, Units 2 and 3, Renewed Facility Operating Licenses.

Exelon has reviewed the information supporting a finding of no significant hazards consideration, and the environmental consideration, that were previously provided to the NRC in Attachment 1 of the Reference 1 letter. Exelon has concluded that the information provided in this response does not affect the bases for concluding that the proposed license amendment does not involve a significant hazards consideration under the standards set forth in 10 CFR 50.92. In addition, Exelon has concluded that the information in this response does not affect the bases for concluding that neither an environmental impact statement nor an environmental assessment needs to be prepared in connection with the proposed amendment.

U.S. Nuclear Regulatory Commission Supplemental Response Application to Adopt 10 CFR 50.69 Docket Nos. 50-277 and 50-278 June 6, 2018 Page 3 There are no regulatory commitments in this submittal.

In accordance with 10 CFR 50.91, "Notice for public comment; State consultation,"

paragraph (b), Exelon is notifying the Commonwealth of Pennsylvania of this supplemental response by transmitting a copy of this letter and its attachments to the designated State Official.

If you have any questions or require additional information, please contact Richard Gropp at 610-765-5557.

I declare under penalty of perjury that the foregoing is true and correct. Executed on the 61h day of June 2018.

Respe~~ ~

James Barstow Director, Licensing and Regulatory Affairs Exelon Generation Company, LLC Attachments:

1. Supplemental Information to Support Application to Adopt 10 CFR 50.69, "Risk-informed categorization and treatment of structures, systems, and components for nuclear power plants"

2. Updated Peach Bottom 10 CFR 50.69 PRA Implementation Items

3. Updated Mark-up of Proposed Renewed Facility Operating License (RFOL) Pages cc: w/ Attachments Regional Administrator - NRC Region I NRC Senior Resident Inspector - Peach Bottom Atomic Power Station NRC Project Manager, NRR - Peach Bottom Atomic Power Station Director, Bureau of Radiation Protection - Pennsylvania Department of Environmental Protection R.R. Janati, Pennsylvania Bureau of Radiation Protection S.T. Gray, State of Maryland

ATTACHMENT 1 License Amendment Request Peach Bottom Atomic Power Station, Units 2 and 3 Docket Nos. 50-277 and 50-278 Supplemental Information to Support Application to Adopt 10 CFR 50.69, 11 Risk-informed categorization and treatment of structures, systems, and components for nuclear power plants 11

Response to Request for Additional Information Attachment 1 Application to Adopt 1o CFR 50.69 Page 1 of 4 Docket Nos. 50-277 and 50-278 Attachment 1 Supplemental Information to Support Application to Adopt 10 CFR 50.69, "Risk-informed categorization and treatment of structures. systems, and components for nuclear power plants" By letter dated August 30, 2017 (Reference 1), Exelon Generation Company, LLC (Exelon) requested an amendment to the Renewed Facility Operating License (RFOL) Nos. DPR-44 and DPR-56 for Peach Bottom Atomic Power Station (PBAPS), Units 2 and 3, respectively. The proposed amendment would modify the licensing basis by the addition of a license condition to allow for the implementation of the provisions of Title 1O of the Code of Federal Regulations (1 O CFR), Part 50.69, "Risk-informed categorization and treatment of structures, systems, and components for nuclear power reactors." In a letter dated October 10, 2017 (Reference 2), the U.S. Nuclear Regulatory Commission (NRC) requested that Exelon provide supplemental information in support of the application. By letter dated October 24, 2017 (Reference 3),

Exelon responded to the NRC's request for supplemental information.

The NRC reviewed the information provided in the Reference 1 and 3 submittals and indicated the need for additional information in order to complete their review and evaluation of the amendment request. In an electronic mail message dated March 21, 2018 (Reference 4), the NRC issued a draft Request for Additional Information (RAI). This draft RAI was the subject of further discussions during a teleconference on April 6, 2018, between Exelon and NRC representatives, and additional clarification was provided. The NRC then issued the formal RAI (Reference 5) in which they requested a response by May 7, 2018. With the exception of Question 10.c, Exelon responded to all other questions in the RAI by letter dated May 7, 2018 (Reference 6).

The request to defer submitting specific information in response to Question 1O.c was discussed with the NRC Project Manager for PBAPS, and a due date of June 6, 2018, was agreed upon for the response to Question 10.c. As indicated in the Reference 6 letter, Exelon noted that additional time was needed in order to fully respond to NRC RAI Question 1O.c in support of the station's continuing efforts to assess tornado missile protection hazards in response to RIS 2015-06, "Tornado Missile Protection," (ML15020A419).

Accordingly, this attachment provides Exelon's response to NRC RAI Question 1O.c. The NRC's question is restated below followed by Exelon's response.

RAI 1O - SSCs Categorization based on External Hazards c) High Winds Figure 5-6 of NE/ 00-04 shows that if a component is included in a screened scenario, then in order for that component to be considered a candidate LSS, the licensee has to show that if the component was removed, the screened scenario would not become unscreened. Attachment 4 of the LAR states that the licensee screens out the extreme wind or tornado hazard on the basis that the frequency of damage to the exposed components is estimated to be less than 1E-6/year. However, the licensee does not provide any information describing the SSCs, if any, that are included in the screening.

Response to Request for Additional Information Attachment 1 Application to Adopt 1o CFR 50.69 Page 2 of 4 Docket Nos. 50-277 and 50-278 Provide the following:

i. A discussion identifying the SSCs, if any, that are credited in the screening of extreme wind and tornados, including passive and/or active components.

Response

At the time of the LAR submittal (Reference 1) there were no Structures, Systems, and Components (SSCs) credited in the screening of extreme winds and tornados, including passive and/or active components, other than Seismic Category I structures.

Such structures are designed to withstand the most severe tornado wind pressure loading, including wind-borne missiles.

The response to item 1O.c.iii below provides an updated discussion of screening of extreme wind and tornados that is included as part of the PBAPS assessment in response to Regulatory Issue Summary (RIS) 2015-06.

ii. A discussion explaining how the licensee will apply the guidance in Figure 5-6 of NE/ 00-04 to any SSCs that are credited for screening of extreme wind and tornados.

Response

PBAPS follows the safety significance process guidance described in Section 5.4 and Figure 5-6 of NEI 00-04, Revision 0, "10 CFR 50.69 SSC Categorization Guideline," as endorsed by Regulatory Guide (RG) 1.201, "Guidelines for Categorizing Structures, Systems, and Components in Nuclear Power Plants According to their Safety Significance." Per the process, all SSCs credited for screening of extreme wind and tornados will be High Safety Significant (HSS). In addition, the attributes which yielded that conclusion will be identified.

iii. Explain how the discussion in items (i) and (ii) above would be impacted by the current effort to assess tornado missile protection hazard in response to RIS 2015-06 'Tornado Missile Protection," (ADAMS Accession No. ML15020A419).

Response

As noted in the RAI response dated May 7, 2018 (Reference 6), Exelon continues its efforts to assess tornado missile protection in response to RIS 2015-06 at PBAPS.

This was also documented in Attachment 4 of the August 30, 2017 (Reference 1) submittal, which indicated the following:

"... The site is currently assessing tornado missile protection (TMP) in response to RIS 2015-06. If additional TMP vulnerabilities are discovered as part of this assessment, PBAPS will update this screening analysis."

Response to Request for Additional Information Attachment 1 Application to Adopt 10 CFR 50.69 Page 3 of 4 Docket Nos. 50-277 and 50-278 TMP issues are being evaluated to determine if they impact the External Hazards screening analysis associated with extreme winds and tornados in support of this License Amendment Request (LAA).

As described in the Reference 1 submittal and in response to item 1O.c.ii above, Exelon will implement the risk categorization process in accordance with the Nuclear Energy Institute (NEI) guidance specified in NEI 00-04, Revision 0, as endorsed by the NRC in RG 1.201. Therefore, per the process, all SSCs credited for screening of extreme wind and tornados will be High Safety Significant (HSS).

To ensure that any potentially risk significant tornado missile hazards and required protection identified in the station's ongoing efforts in response to RIS 2015-06 are appropriately reflected in the 10 CFR 50.69 categorization process, Exelon proposes to include the following item in the "Peach Bottom 50.69 PAA Implementation Items" table that will be referenced as a license condition in the RFOLs for PBAPS, Units 2 and 3, to facilitate implementation 10 CFR 50.69 once approved:

"Exelon shall complete any necessary actions (e.g., analyses, modifications, etc.)

to screen tornado missile hazards in accordance with the original license amendment request submittal dated August 30, 2017. This hazard screening will be completed prior to implementation of License Amendment XXX involving adoption of 1o CFR 50. 69."

Attachment 2 of this letter contains the updated list of 50.69 Probabilistic Risk Assessment (PAA) implementation items, including the action cited above (refer to Item #12 in the table). This updated table supersedes the previous Attachment 2 table listing provided in Reference 5. Attachment 3 contains the proposed markups of the PBAPS, Units 2 and 3, Renewed Facility Operating Licenses.

References:

1. Letter from James Barstow (Exelon Generation Company, LLC) to U.S. Nuclear Regulatory Commission - "Application to Adopt 10 CFR 50.69, 'Risk-informed categorization and treatment of structures, systems, and components for nuclear power plants,"' dated August 30, 2017(ML17243A014)

2. Letter from Richard B. Ennis (U.S. Nuclear Regulatory Commission) to Bryan C. Hanson, Exelon Generation Company, LLC- "Supplemental Information Needed for Acceptance of Requested Licensing Action Re: Adoption of title 1O of the Code of Federal Regulations Section 50.69," dated October 10, 2017 (ML17272B016)

3. Letter from James Barstow (Exelon Generation Company, LLC) to U.S. Nuclear Regulatory Commission - "Supplement to Application to Adopt 10 CFR 50.69, Risk-Informed Categorization and Treatment of Structures, Systems, and Components for Nuclear Power Reactors," dated October 24, 2017 (ML17297B521)

4. Electronic mail message from Jennifer Tobin (U.S. Nuclear Regulatory Commission) to David Helker, Exelon Generation Company, LLC- "Draft 50.69 Request for Additional Information (RAls)- Peach Bottom," dated March 21, 2018

Response to Request for Additional Information Attachment 1 Application to Adopt 10 CFR 50.69 Page 4 of 4 Docket Nos. 50-277 and 50-278

5. Electronic mail message from Jennifer Tobin (U.S. Nuclear Regulatory Commission) to David Helker, Exelon Generation Company, LLC - "Peach Bottom Units 2 and 3 - Request for Additional Information -Adopt 50.69 License Amendment," dated April 6, 2018

6. Letter from James Barstow (Exelon Generation Company, LLC) to U.S. Nuclear Regulatory Commission - "Response to Request for Additional Information Application to Adopt 10 CFR 50.69, "Risk-informed categorization and treatment of structures, systems, and components for nuclear power plants," dated May 7, 2018(ML18128A009)

Supplemental Information Attachment 2 Application to Adopt 1o CFR 50.69 Page 1 of 3 Docket Nos. 50-277 and 50-278 ATTACHMENT 2 License Amendment Request Peach Bottom Atomic Power Station, Units 2 and 3 Docket Nos. 50-277 and 50-278 Supplemental Information to Support Application to Adopt 10 CFR 50.69, 11 Risk-informed categorization and treatment of structures, systems, and components for nuclear power plants 11 Updated Peach Bottom 50.69 PRA Implementation Items The items identified in the table below are required to be completed prior to implementation of the 10 CFR 50.69 risk categorization process. All issues identified below will be addressed and any associated changes will be made, focused-scope peer reviews will be performed on changes that are Probabilistic Risk Assessment (PRA) upgrades as defined in the PRA Standard ASME/ANS RA-Sa-2009, as endorsed by Regulatory Guide (RG) 1.200, Revision 2, "An Approach for Determining the Technical Adequacy of Probabilistic Risk Assessment Results for Risk-Informed Activities," and any findings will be resolved and reflected in the PRA of record prior to implementation of the 10 CFR 50.69 categorization process.

Peach Bottom 50.69 PRA Implementation Items Item# Description 1 The HRA pre-initiators in the internal events PRA model will be updated to meet Capability Category II of the ASME/ANS RA-Sa-2009 as endorsed by RG 1.200, Revision 2. A focused-scope peer review will be conducted of the pre-initiator analysis, and any resulting F&Os will be resolved, as indicated in response to RAI 03.a contained in Exelon letter dated May 7, 2018.

2 The transient floor area ratios (FARs) in the fire PRA will be adjusted to consider the treatment of obstructed floor space to provide a more accurate distribution of transient ignition frequency, as indicated in response to RAI 03.b contained in Exelon letter dated May 7, 2018.

3 Risk significant fire PRA scenarios for ignition sources capable of being modeled with a two-point fire modeling approach will be updated to include the two-point fire modeling approach, as indicated in response to RAI 03.c contained in Exelon letter dated May 7, 2018.

4 A review will be conducted of potentially vulnerable fire wrap configurations to identify which are subject to mechanical damage. The fire PRA will be updated to ensure that fire wrap configurations are not credited in fire scenarios that could subject it to mechanical damage, as indicated in response to RAI 03.d contained in Exelon letter dated May 7, 2018.

Supplemental Information Attachment 2 Application to Adopt 10 CFR 50.69 Page 2 of 3 Docket Nos. 50-277 and 50-278 Peach Bottom 50.69 PRA Implementation Items Item# Description 5 The categorization process includes the fire PRA sensitivity studies from NEI 00-04 Table 5-3 which includes the sensitivity study to remove all credit for manual suppression. Another fire PRA sensitivity study will be performed as part of the categorization process that assumes credit for immediate manual suppression, as indicated in response to RAI 04.a contained in Exelon letter dated Mav 7, 2018.

6 Sources of uncertainty associated with implementation of FLASHCAT in the fire PRA introduced through use of generic parameters from NUREG-7010 Vol. 1 and weighted averages of parameters for cables located within the physical analysis units in which the scenarios implementing the FLASHCAT model were located will be removed by basing values for these parameters (mass per unit length and plastic mass fraction) on the scenario specific set of cables that are located within the cable trays analyzed using the FLASHCAT model, as indicated in response to RAI 04.a and RAI 04.d contained in Exelon letter dated May 7, 2018.

7 The NUREG-1921 methodology will be applied in identifying undesired operator actions and will be used to incorporate any identified actions into the fire PRA. A focused-scope peer review of the application of this methodology will be performed, and any new F&Os resulting from the focused scope review will be resolved, as indicated in response to RAI 05.a contained in Exelon letter dated May 7, 2018.

8 The fire PRA model will be updated to address breaker coordination in non-safety related power supplies credited in the model by assuming failure of the power supply, including accounting for opening of the power supply upstream breaker that may occur due to the potential lack of coordination between it and the downstream breaker associated with the damaged power cable, when the power cable within the circuits of concern are identified to be damaged by fire scenarios, or additional analysis will be performed to determine that circuits are coordinated, as indicated in response to RAI 05.b contained in Exelon letter dated May 7, 2018.

9 The PRA model will be updated to account for the requirement for two EOG cooling fans during periods when the outdoor temperatures at Peach Bottom are above the design temperature of 80° F, as indicated in response to RAI 08.a contained in Exelon letter dated May 7, 2018.

10 The pipe rupture frequencies will be updated in the internal flooding PRA to the most recent EPRI pipe rupture frequencies, as indicated in Exelon's letter dated August 30, 2017.

11 Credit for core melt arrest in-vessel at high reactor pressure vessel (RPV) pressure conditions will be removed from the internal events PRA model, as indicated in Exelon's letter dated August 30, 2017.

12 Exelon shall complete any necessary actions (e.g., analyses, modifications, etc.) to screen tornado missile hazards in accordance with the original license amendment request submittal dated August 30, 2017. This hazard screening will be completed prior to implementation of License Amendment XXX involving adoption of 10 CFR 50.69.

Supplemental Information Attachment 2 Application to Adopt 10 CFR 50.69 Page 3 of 3 Docket Nos. 50-277 and 50-278 Peach Bottom 50.69 PRA Implementation Items Item# Description 13 All ASME Code Class 1 SSCs with a pressure retaining function, as well as supports, will be designated high safety-significant (HSS) for passive categorization which will result in HSS for its risk-informed safety classification, and cannot be chanoed bv the IDP (RAI 15).

ATTACHMENT 3 License Amendment Request Peach Bottom Atomic Power Station, Units 2 and 3 Docket Nos. 50-277 and 50-278 Response to Request for Additional Information Application to Adopt 10 CFR 50.69, "Risk-informed categorization and treatment of structures, systems, and components for nuclear power plants" Updated Mark-up of Proposed Renewed Facility Operating License (RFOL) Pages Unit 2 RFOL Pages 7g Unit 3 RFOL Pages 7g

2. Level 1 performance criteria.

3. The methodology for establishing the RSD strain limits used for the Level 1 and Level 2 performance.

(e) The results of the power ascension testing to verify the continued structural integrity of the steam dryer shall be submitted to the NRC staff in a report in accordance with 10 CFR 50.4. The report shall include a final load definition and stress report of the steam dryer, including the results of a complete re-analysis using the end-to-end B/Us determined at EPU conditions and a comparison of predicted and measured pressures and strains (RMS levels and spectra) on the RSD. The report shall be submitted within 90 days of the completion of EPU power ascension testing for Peach Bottom Unit 2.

(f) During the first two scheduled refueling outages after reaching EPU conditions, a visual inspection shall be conducted of the steam dryer as described in the inspection guidelines contained in WCAP-17635-P.

(g) The results of the visual inspections of the steam dryer shall be submitted to the NRC staff in a report in accordance with 10 CFR 50.4. The report shall be submitted within 90 days following startup from each of the first two respective refueling outages.

(h) Within 6 months following completion of the second refueling outage, after the implementation of the EPU, the licensee shall submit a long-term steam dryer inspection plan based on industry operating experience along with the baseline inspection results.

The license condition described above shall expire: (1) upon satisfaction of the requirements in paragraphs (f) and (g), provided that a visual inspection of the steam dryer does not reveal any new unacceptable flaw(s) or unacceptable flaw growth that is due to fatigue, and; (2) upon satisfaction of the requirements specified in paragraph (h).

(16) Maximum Extended Load Line Limit Analysis Plus (MELLLA+) Special Consideration The licensee shall not operate the facility within the MELLLA+ operating domain with a feedwater heater out of service resulting in more than a 10°F reduction in feedwater temperature below the design feedwater temperature.

Renewed License No. DPR-44 Amendment No. 305 7g

(e) The results of the power ascension testing to verify the continued structural integrity of the steam dryer shall be submitted to the NRC staff in a report in accordance with 10 CFR 50.4. The report shall include a final load definition and stress report of the steam dryer, including the results of a complete re-analysis using the end-to-end B/Us from Peach Bottom Unit 2 benchmarking at EPU conditions. The report shall be submitted within 90 days of the completion of EPU power ascension testing for Peach Bottom Unit 3.

(f) During the first two scheduled refueling outages after reaching EPU conditions, a visual inspection shall be conducted of the steam dryer as described in the inspection guidelines contained in WCAP-17635-P .

(g) The results of the visual inspections of the steam dryer shall be submitted to the NRC staff in a report in accordance with 10 CFR 50.4. The report shall be submitted within 90 days following startup from each of the first two respective refueling outages.

(h) Within 6 months following completion of the second refueling outage, after the implementation of the EPU, the licensee shall submit a long-term steam dryer inspection plan based on industry operating experience along with the baseline inspection results.

The license condition described above shall expire: (1) upon satisfaction of the requirements in paragraphs (f) and (g), provided that a visual inspection of the steam dryer does not reveal any new unacceptable flaw(s) or unacceptable flaw growth that is due to fatigue, and; (2) upon satisfaction of the requirements specified in paragraph (h).

(16) Maximum Extended Load Line Limit Analysis Plus (MELLLA+) Special Consideration The licensee shall not operate the facility within the MELLLA+ operating domain with a feedwater heater out of service resulting in more than a INSERT 1 10°F reduction in feedwater temperature below the design feedwater temperature.

3. This renewed license is subject to the following conditions for the protection of the environment:

A. To the extent matters related to thermal discharges are treated therein, operation of Peach Bottom Atomic Power Station, Unit No. 3, will be governed by NPDES Permit No. PA 0009733, as now in effect and as hereafter amended. Questions pertaining to conformance thereto shall be referred to and shall be determined by the NPDES Permit issuing or enforcement authority, as appropriate.

B. In the event of any modification of the NP DES Permit related to thermal discharges or the establishment (or amendment) of alternative effluent limitations established pursuant to Section 316 of the Federal Water Pollution Control Act, the Exelon Generation Company shall inform the NRC and analyze any associated changes in or to the Station, its components, its operation or in the discharge of effluents therefrom . If such change would entail any modification to Renewed License No. DPR-56 Amendment No. 309 Page 7g

License Amendment Request Peach Bottom Atomic Power Station Units 2 and 3 Adoption of 10 CFR 50.69 License Condition Mark-ups for Renewed Facility Operating Licenses (RFOL)

Unit 2 - Insert 1 (17) Adoption of 10 CFR 50.69, "Risk-informed categorization and treatment of structures. systems. and components for nuclear power plants" In support of implementing License Amendment No. XXX permitting the adoption of the provisions of 10 CFR 50.69 for Renewed Facility Operating License No.

DPR-44 for Peach Bottom Unit 2, the license is amended to add the following license condition:

Prior to the implementation of the provisions of 10 CFR 50.69, the conditions specified below shall be completed:

a) Exelon is approved to implement 10 CFR 50.69 using the processes for categorization of Ris_k-lnformed Safety Class (RISC)-1, RISC-2, RISC-3, and RISC-4 structures, systems, and components (SSCs) specified in the license amendment dated [DATE] subject to the following condition:

Exelon will complete the implementation items listed in Attachment 2 of Exelon's letter to the NRC dated June 6, 2018, prior to implementation of 10 CFR 50.69. All issues identified in the attachment will be addressed and any associated changes will be made, focused-scope peer reviews will be performed on changes that are PAA upgrades as defined in the PAA standard (ASME/ANS RA-Sa-2009, as endorsed by RG 1.200, Revision 2), and any findings will be resolved and reflected in the PAA of record prior to implementation of the 10 CFR 50.69 categorization process.

Prior NRC approval, under 10 CFR 50.90, is required for a change to the categorization process specified above (e.g., change from a seismic margins approach to a seismic probabilistic risk assessment approach).

Unit 3 - Insert 1 (17) Adoption of 10 CFR 50.69, "Risk-informed categorization and treatment of structures, systems, and components for nuclear power plants" In support of implementing License Amendment No. XXX permitting the adoption of the provisions of 10 CFR 50.69 for Renewed Facility Operating License No.

DPR-56 for Peach Bottom Unit 3, the license is amended to add the following license condition:

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Prior to the implementation of the provisions of 10 CFR 50.69 the conditions specified below shall be completed:

a) Exelon is approved to implement 10 CFR 50.69 using the processes for categorization of Risk-Informed Safety Class (RISC)-1, RISC-2, RISC-3, and RISC-4 structures, systems, and components (SSCs) specified in the license amendment dated [DATE] subject to the following condition:

Exelon will complete the implementation items listed in Attachment 2 of Exelon's letter to the NRC dated June 6, 2018, prior to implementation of 10 CFR 50.69. All issues identified in the attachment will be addressed and any associated changes will be made, focused-scope peer reviews will be performed on changes that are PAA upgrades as defined in the PAA standard (ASME/ANS RA-Sa-2009, as endorsed by RG 1.200, Revision 2), and any findings will be resolved and reflected in the PAA of record prior to implementation of the 10 CFR 50.69 categorization process.

Prior NRC approval, under 10 CFR 50.90, is required for a change to the categorization process specified above (e.g., change from a seismic margins approach to a seismic probabilistic risk assessment approach).

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