L-2023-094, Response to Requests for Additional Information Regarding License Amendment Request No. 276, Revise Fire Protection Program in Support of Reactor Coolant Pump Seal Replacement Project

Response to Requests for Additional Information Regarding License Amendment Request No. 276, Revise Fire Protection Program in Support of Reactor Coolant Pump Seal Replacement Project

ML23208A191
Person / Time
Site:	Turkey Point
Issue date:	07/27/2023
From:	Strand D Florida Power & Light Co
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
L-2023-094
Download: ML23208A191 (1)

Text

U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington DC 20555-0001 RE:

Turkey Point Nuclear Generating Station, Units 3 and 4 Docket Nos. 50-250 and 50-251 Subsequent Renewed Facility Operating Licenses DPR-31 and DPR-41 July 27, 2023 L-2023-094 10 CFR 50.90 Response to Requests for Additional Information Regarding License Amendment Request No. 276, Revise Fire Protection Program in Support of Reactor Coolant Pump Seal Replacement Project

References:

1. License Amendment Request No. 276, Revise Fire Protection Program in Support of Reactor Coolant Pump Seal Replacement Project, dated August 26, 2022 (ADAMS Accession No. ML22243A161)

2. NRC electronic memorandum dated May 5, 2023, RAls - Turkey Point RCP Seal LAR (ADAMS Accession No. ML23129A832)

3. Response to Requests for Add itional Information Regarding License Amendment Request No.

276, Revise Fire Protection Program in Support of Reactor Coolant Pump Seal Replacement Project, dated May 31, 2023 (ADAMS Accession No. ML23151A607)

In Reference 1 Florida Power & Light Company (FPL) submitted license amendment request 276 for Turkey Point Nuclear Generating Station, Units 3 and 4 (Turkey Point). The proposed license amendment is requested in accordance with the Turkey Point Units 3 and 4 Subsequent Renewed Facility Operating Licenses (SRFOL) Paragraph 3.D, Fire Protection, for fire protection program changes that may be made without prior NRC approval. One of the criteria for such a change is that the risk increase resulting from the change is less than 1x10-7/year (yr) for Core Damage Frequency (CDF) and less than 1 x 10-8/yr for Large Early Release Frequency (LERF). The plant change to be evaluated is the replacement of the currently installed reactor coolant pump (RCP) seals with the Framatome RCP hydrostatic seal package equipped with the Passive Shutdown Seal (PSDS). FPL's evaluation of the proposed RCP seal replacement against the criteria of SRFOL Paragraph 3.D, concluded that the threshold for self-approval is exceeded and therefore, prior NRC approval is sought.

In Reference 2 the NRC requested additional information deemed necessary to complete its review.

Reference 3 provided responses to some of the requested information. provides FPL's response to the remaining requests for additional information (RAI) from Reference 2.

The information included in this RAI response provides additional information that clarifies the application, does not expand the scope of the application as originally noticed, and should not change the NRC staff's originally proposed no significant hazards consideration determination as published in the Federal Register.

This letter contains no new regulatory commitments.

Florida Power & Light Company 6501 S. Ocean Drive, Jensen Beach, FL 34957

Turkey Point Nuclear Plant Docket Nos. 50-250 and 50-251 L-2023-094 Page 2 of 2 Should you have any questions regarding this submittal, please contact Mr. Kenneth Mack, Fleet Licensing Manager at 561-904-3635.

I declare under penalty of perjury that the foregoing is true and correct.

Executed on the 27th day of July 2023.

Dianne S and General anager, Regulatory Affairs Florida Power & Light Enclosure cc:

USNRC Regional Administrator, Region II USNRC Project Manager, Turkey Point Nuclear Generating Station USNRC Senior Resident Inspector, Turkey Point Nuclear Generating Station Mr. Clark Eldredge, Florida Department of Health

Turkey Point Nuclear Plant Docket Nos. 50-250 and 50-251 ENCLOSURE Response to Request for Additional Information (RAI)

Turkey Point Nuclear Plant Unit 3 and Unit 4 L-2023-094 License Amendment Request, Revise Fire Protection Program in Support of Reactor Coolant Pump Seal Replacement Project

Turkey Point Nuclear Plant Docket Nos. 50-250 and 50-251 Response to Request for Additional Information (RAI)

Turkey Point Nuclear Plant Unit 3 and Unit 4 L-2023-094 Enclosure Page 1 of 6 License Amendment Request, Revise Fire Protection Program in Support of Reactor Coolant Pump Seal Replacement Project NRC Staff Requests for Additional Information (RAls)

1.

RAI 1 response provided in Reference 1.

2.

Section 3.3 (Risk Analysis Results) of the LAR reports the total core damage frequency (CDF) for full power internal events, internal flood, and fire probabilistic risk assessment (PRA) for U3 and U4 as 8.01 E-5 and 7.82E-5, respectively. However, there is no estimate for seismic and other external hazards. Provide seismic and other external hazard contributions to CDF/LERF, or alternately provide a justification for why the Regulatory Guide 1.17 4, "An Approach For Using Probabilistic Risk Assessment In Risk-Informed Decisions On Plant-Specific Changes To The Licensing Basis," Revision 3, guidelines are met without quantitative contributions from those hazards. Provide a discussion for how, after taking uncertainty into account for the addition of seismic and other external hazards, the total CDF and LERF will not exceed the RG 1.17 4 acceptance guidelines.

FPL Response - RAI 2 Due to the plant being located in a region of very low seismicity, a seismic PRA was not developed for Turkey Point; however, a bounding estimate of the seismic CDF was calculated by integrating the latest seismic hazard curves for Turkey Point with a plant-level fragility curve. The plant-level fragility represents the plant as a whole rather than the component-level fragilities used in a full seismic PRA The plant-level fragility does not take credit for any of the components that are designed to withstand earthquakes whose severity is greater than the High-Confidence-of-Low-Probability-of-Failure (HCLPF) of 0.15g. Therefore, the seismic CDF calculated in this manner is conservative.

The seismic CDF obtained by integrating the Turkey Point-specific seismic hazard curve from the recent EPRI study (Reference 2) and the plant-level seismic fragility curve from the Gl-199 (Reference 3) calculations resulted in a seismic CDF estimate of 6.98E-07 per year. The seismic LERF contribution is estimated at one-tenth of the seismic CDF, resulting in a Large Early Release Frequency (LERF) contribution of 6.98E-08 per year. These values are applicable to Turkey Point Unit 3 and Unit 4.

This approach, and the above risk values, were used in the Risk Informed Completion Time (RICT}

license amendment request (LAR) (Reference 4). Enclosure 4 of that request evaluates the contribution of other external events and concludes that the seismic contribution is the only external event with a quantifiable value that was used in support of that application.

The updated total (Fire, Full Power Internal Events (FPIE), Internal Flooding (IF)) risk reported in the response to RAI 5 is updated in the table below to incorporate the above risk values. The reactor coolant pump (RCP) seal replacement does not contain components or configurations that are sensitive to a seismic event or that would be impacted by other external events in a manner different than that evaluated in the RICT LAR, therefore, the risk specified above is considered an appropriate bounding value for the current plant, as well as the post RCP seal modification configuration. Therefore, the total CDF and LERF does not exceed the RG 1.17 4 acceptance guidelines.

The risk values reported below reflect the current analysis results, incorporating changes resulting from other RAls and associated internal reviews.

Turkey Point Nuclear Plant Docket Nos. 50-250 and 50-251 Response to Request for Additional Information (RAI)

Turkey Point Nuclear Plant Unit 3 and Unit 4 L-2023-094 Enclosure Page 2 of 6 License Amendment Request, Revise Fire Protection Program in Support of Reactor Coolant Pump Seal Replacement Project Total Fire, FPIE and IF and Seismic Risk RGP Seal Mod Results Post Mod/Pre-Mod and Delta Risk (w/%

incr.)

Unit GDF post mod GDF pre mod, with refinements

./JGDF lncreas e

LERF post mod LERF pre mod, with refinements

./JLERF lncreas e

Unit 3 7.05E-05 6.62E-05 4.30E-06 6%

1.59E-06 1.56E-06 3.00E-08 Unit 4 7.58E-05 7.12E-05 4.61 E-06 6%

1.61 E-06 1.57E-06 4.00E-08

3.

Appendix A of Attachment 1 of the LAR uses the fire CDF and LERF to determine the internal events/flooding delta CDF and LERF. The LAR indicates that fire induced failures of systems to prevent the loss of the RCP seals are larger than random failures; thus, extrapolating internal events/flooding delta CDF and LERF from fire is conservative.

However, the NRC staff notes that other fire damage in general plays a role in these scenarios, and thus, comparing the fire induced failure of systems relevant to loss of the RCP seals is only one factor, and perhaps not the dominant factor. Therefore, the NRC staff does not have sufficient information to determine whether the delta risk from internal events/flooding being derived from fires only would be an acceptable approach. As a result, provide a calculation of internal events/flooding delta CDF/LERF which relies only on the internal events/flooding PRA model, and is not extrapolated from the fire PRA model.

FPL Response - RAI 3 See response to RAI 5 for the results of the updated internal events/flooding PRA model.

4.

RAI 4 response provided in Reference 1.

5.

Indicate whether the IE/flooding model of record identified in Appendix A of Attachment 1 to the LAR is the latest version of this PRA and includes the proposed RCP seal change described in the LAR. If not, indicate why the CDF and LERF of these hazards is acceptable, or otherwise provide quantitative risk values which incorporates the proposed seal changes.

2%

3%

Turkey Point Nuclear Plant Docket Nos. 50-250 and 50-251 Response to Request for Additional Information (RAI)

Turkey Point Nuclear Plant Unit 3 and Unit 4 L-2023-094 Enclosure Page 3 of 6 License Amendment Request, Revise Fire Protection Program in Support of Reactor Coolant Pump Seal Replacement Project FPL Response - RAI 5 The results identified in Attachment 1, Appendix A, of RCP seal replacement LAR (Reference 5) reflect the sum of the FPIE and IF risk for the current plant configuration with a bounding calculation, based on the risk increase associated with the seal replacement quantification in the Fire PRA. The FPIE/IF risk analyses have been updated to reflect incorporation of the RCP seal replacement modifications.

These risk results are provided in the following Tables. The updated fire risk results are also provided below to reflect the update associated with generation of a one-top model addressing all three hazards.

Table 1 - Updated Fire Risk Results (includes post RCP seal mod, pre-RCP seal mod and delta risk)

Table 2 - Full Power Internal Events Risk Results (includes post RCP seal mod, pre-RCP seal mod and delta risk)

Table 3 - Internal Flooding Risk Results (includes post RCP seal mod, pre-RCP seal mod and delta risk)

Table 4 - Total Fire, FPIE, IF and Seismic Risk Results (includes post RCP seal mod, pre-RCP seal mod and delta risk)

See the RAI 2 response for a discussion and a tabulation of the impact of other external risk hazard contributors, including seismic risk.

The risk values reported below reflect the current analysis results, incorporating changes resulting from other RAls and associated internal reviews.

Turkey Point Nuclear Plant Docket Nos. 50-250 and 50-251 Response to Request for Additional Information (RAI)

Turkey Point Nuclear Plant Unit 3 and Unit 4 L-2023-094 Enclosure Page 4 of 6 License Amendment Request, Revise Fire Protection Program in Support of Reactor Coolant Pump Seal Replacement Project Table 1: Updated Fire Risk Results GDF post GDF pre mod, with LERF post LERF pre mod, with Unit mod refinements

.liGDF

% Increase mod refinements liLERF Unit 3 6.96E-05 6.53E-05 4.30E-06 7%

1.51 E-06 1.48E-06 3.00E-08

% Increase 2%

Unit4 7.49E-05 7.03E-05 4.60E-06 7%

1.53E-06 1.49E-06 4.00E-08 3%

Table 2: Full Power Internal Events(FPIE) Risk Results GDF post GDF pre mod, with LERF post LERF pre mod, Unit mod refinements

.liGDF

% Increase mod with refinements liLERF

% Increase Unit 3 2.07E-07 2.04E-07 3.00E-09 1%

8.63E-09 8.61 E-09 2.00E-11 0.2%

Unit4 2.18E-07 2.12E-07 6.00E-09 3%

8.50E-09 8.48E-09 2.00E-11 0.2%

Turkey Point Nuclear Plant Docket Nos. 50-250 and 50-251 Response to Request for Additional Information (RAI)

Turkey Point Nuclear Plant Unit 3 and Unit 4 L-2023-094 Enclosure Page 5 of 6 License Amendment Request, Revise Fire Protection Program in Support of Reactor Coolant Pump Seal Replacement Project Table 3: Internal Flooding (IF) Risk Results CDF post COF pre mod, with LERF post LERF pre mod, Unit mod refinements

/J.COF

% Increase mod with refinements

/J.LERF Unit 3 2.11 E-08 2.09E-08 2.00E-10 1%

1.63E-10 1.60E-10 3.00E-12

% Increase 2%

Unit4 7.86E-10 7.57E-10 2.90E-11 4%

1.02E-11 9.48E-12 7.20E-13 8%

Table 4: Total Fire, FPIE, IF and Seismic Risk Results COF post CDF pre mod, with LERF post LERF pre mod, Unit mod refinements

/J.CDF

% Increase mod with refinements

/J.LERF

% Increase Unit 3 7.05E-05 6.62E-05 4.30E-06 6%

1.59E-06 1.56E-06 3.00E-08 2%

Unit4 7.58E-05 7.12E-05 4.61 E-06 6%

1.61 E-06 1.57E-06 4.00E-08 3%

Turkey Point Nuclear Plant Docket Nos. 50-250 and 50-251 Response to Request for Additional Information (RAI)

Turkey Point Nuclear Plant Unit 3 and Unit 4 L-2023-094 Enclosure Page 6 of 6 License Amendment Request, Revise Fire Protection Program in Support of Reactor Coolant Pump Seal Replacement Project

6.

RAI 6 response provided in Reference 1.

7.

RAI 7 response provided in Reference 1.

8.

RAI 8 response provided in Reference 1.

9.

RAI 9 response provided in Reference 1.

10. RAI 10 Response provided in Reference 1.

References

1.

Response to Requests for Additional Information Regarding License Amendment Request No.

276, Revise Fire Protection Program in Support of Reactor Coolant Pump Seal Replacement Project, dated May 31, 2023 (ADAMS Accession No. ML23151A607)

2.

Lettis Consultants International (LCI) Project Report, Turkey Point Seismic Hazard and Screening Report, Calculation of Seismic Hazards for CEUS Sites, Project No. 1041, Nicholas Graehl, dated February 14, 2014.

3.

Results of Safety/Risk Assessment of Generic Issue 199, "Implications of Updated Probabilistic Seismic Hazard Estimates in Eastern United States on Existing Plants, Appendix C, Plant-Level Fragility Data," August 2010 (ADAMS Accession No. ML100270731)

4.

License Amendment Request No. 236, Revision to the Technical Specifications to Adopt Risk Informed Completion Times, TSTF-505, Revision 1, "Provide Risk Informed Extended Completion Times-RITSTF Initiative 4B," dated December 23, 2014 (ADAMS Accession No. ML15029A297)

5.

License Amendment Request No. 276, Revise Fire Protection Program in Support of Reactor Coolant Pump Seal Replacement Project, dated August 26, 2022 (ADAMS Accession No. ML22243A161)