L-2024-066, Sixth 10-Year Inservice Testing Interval Relief Request No. PR-02
| ML24108A091 | |
| Person / Time | |
|---|---|
| Site: | Turkey Point  |
| Issue date: | 04/17/2024 |
| From: | Rasmus P Florida Power & Light Co |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| L-2024-066 | |
| Download: ML24108A091 (1) | |
Text
F=PL.
U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington D C 20555-0001 RE:
Turkey Point Nuclear Plant, Unit 3 and 4 Docket Nos. 50-250 and 50-251 Subsequent Renewed Facility Operating Licenses DPR-31 and DPR-41 Sixth 10-Year lnservice Testing Interval Relief Request No. PR-02 April 17, 2024 L-2024-066 10 CFR 50.55a Pursuant to 10 CFR 50.55a(z)(1 ), Florida Power & Light Company (FPL) requests approval of an alternative to the requirements of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code, Operation and Maintenance of Nuclear Power Plants, 2020 Edition (ASME OM Code) for the Turkey Point Unit 3 and Unit 4 (Turkey Point) Sixth 10-Year lnservice Testing (1ST) Interval.
Specifically, FPL requests for Residual Heat Removal (RHR) pump inservice testing conducted at Turkey Point, relief from the instrument range requirements of ASME OM Code, Section ISTB-351 O(b)(1 ), on the basis that the proposed alternative would provide an acceptable level of quality and safety.
The enclosure to this letter provides FPL's evaluation of the proposed alternative. Timely approval is requested to support the start of the Turkey Point Sixth 10-Year 1ST Interval, which begins February 22, 2025 for Unit 3 and April 15, 2025 for Unit 4. A similar request for the RHR pump inservice testing was previously approved for Turkey Point's Fifth 10-Year 1ST Interval (ADAMS Accession No. ML16011A205).
This letter contains no new or modified regulatory commitments.
Should you have any questions regarding this submission, please contact Mr. Kenneth Mack, Fleet Licensing Manager, at 561-904-3635.
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Paul Rasmus General Manager, Regulatory Affairs Florida Power & Light Company cc:
USNRC Regional Administrator, Region II USNRC Project Manager, Turkey Point Nuclear Generating Station USN RC Senior* Resident Inspector, Turkey Point Nuclear Generating Station Mr. Clark Eldredge, Florida Department of Health
Enclosure:
Florida Power & Light Company 9760 SW 344th Street, Homestead, FL 33035
Turkey Point Nuclear Plant Docket Nos. 50-250 and 50-251 L-2024-066 Enclosure Page 1 of 3
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Turkey Point Units 3 and 4 Sixth 10-Year lnservice Testing Interval Relief Request Number PR-02 American Society of Mechanical Engineers (ASME) Code Components Affected Pump Description Code OM Code Number Class Category 3P210A 3A Residual Heat Removal Pump 2
Group A 3P2108 38 Residual Heat Removal Pump 2
Group A 4P210A 4A Residual Heat Removal Pump 2
Group A 4P2108 48 Residual Heat Removal Pump 2
Group A
Applicable Code Edition and Addenda
ASME OM Code, Operation and Maintenance of Nuclear Power Plants, 2020 Edition, no Addenda
Applicable Code Requirement
IST8-3510, General, paragraph (b) Range, subparagraph (1) states The full-scale range of each analog instrument shall be not greater than three times the reference value."
Reason for Request
Pursuant to 1 O CFR 50.55a, "Codes and standards," paragraph (z)(1 ), an alternative is proposed to the instrumentation requirements of the ASME OM Code. The basis of the request is that the proposed alternative would provide an acceptable level of quality and safety. Specifically, this alternative is requested for Group A testing for the Residual Heat Removal (RHR) pumps.
At Turkey Point the RHR pumps are considered Group A pumps. The installed suction and discharge pressure gauges are sized to accommodate pressures up to 600 psig expected under standby, cold shutdown, and emergency operation modes. The instrument range is O to 600 psig.
During the quarterly testing the typical RHR pump differential pressure (delta-P) is approximately 142 psig (discharge pressure approximately 160 psig and suction pressure approximately 18 psig) and as a result the installed suction and discharge pressure instrument ranges exceed the maximum Code allowed range of three times the reference value for the quarterly surveillances.
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Proposed Alternative and Basis for Use As an alternative, Florida Power & Light Company (FPL) proposes to use the existing permanently installed Turkey Point RHR Pump instrumentation.
This currently installed instrumentation, while not meeting the range requirements of IST8-351 O(b)(1 ), exceeds the OM Code required accuracy of 2% required for the Group A quarterly tests of the RHR pumps. This request does not apply to the RHR comprehensive pump testing.
Table 1, "Comparison of Pressure Instrument Ranges and Accuracies," presents a comparison between the permanently installed pressure gauges on the suction and discharge piping of the RHR pumps along with the Code required ranges and accuracies for the Group A quarterly tests.
The existing RHR suction and discharge pressure instruments are calibrated to an accuracy of
+/- 0.25 % and are of the "twice around" type such that they may accurately indicate pressure over all modes of RHR operations (Shutdown Cooling and Emergency Core Cooling). The
Turkey Point Nuclear Plant Docket Nos. 50-250 and 50-251 L-2024-066 Enclosure Page 2 of 3 instrument range on the first revolution is O to 300 psig and 300 to 600 psig on the second revolution.
Suction Pressure Suction pressure measurements are recorded and used to derive the pump differential pressure through calculation. The accuracy of the suction pressure measurement normally has little effect on the results of this calculation since, generally, the pump discharge pressure exceeds the suction pressure by 6 to 7 times the reference value.
When determining pump differential pressure (DP), the RHR pump DP is approximately 142 psi (discharge pressure approximately 160 psig, while suction pressure is approximately 18 psig). The maximum effect of suction pressure inaccuracies is 0.25% x 600 psig, or 1.5 psig. The Code required gauge range for this suction pressure reference value (18 psig) would be O to 54 psig. The Code accuracy requirement of 2% would cause a maximum inaccuracy of 2.0% x 54 psig, or 1.1 psig, as presented in Table 1.
Discharge Pressure Discharge pressure measurements are also recorded and used to derive the pump differential pressure through calculation. The maximum effect of the discharge pressure inaccuracies is 0.25% x 600 psig, or 1.5 psig. The Code required gauge range for the nominal discharge pressure reference value (160 psig) would be Oto 480 psig. The Code accuracy requirement of 2% would cause a maximum inaccuracy of 2.0% x 480 psig, or 9.6 psig, as presented in Table
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Combination Based on the inaccuracies of the suction and discharge pressure gauges (+/- 1.5 psig), the largest possible error in the differential pressure calculation is+/- 3 psig. Use of gauges with Code required ranges, and applying the Code accuracy requirements, the largest possible inaccuracies would be 1.1 psig + 9.6 psig, or 10. 7 psig, as presented in Table 1.
Therefore, the use of permanently installed pressure instruments would reduce the overall instrument inaccuracies with respect to the differential pressure for the quarterly test from 10.7 psig to 3.0 psig.
Using the provisions of this request (to use the permanently installed pressure instrumentation) as an alternative to the specific requirements of ISTB-351 O(b)(1) identified above for the RHR Group A quarterly tests will provide adequate indication of pump performance and continue to provide an acceptable level of quality and safety.
Table 1, Comparison of Pressure Instrument Ranges and Accuracies Suction Pressure Gauge Range Accuracy Suction Pressure Inaccuracy Turkey Point 0 - 600 psig 0.25%
1.5 psig Group A 0- 54* psig 2.0%
1.1 psig
- Suction Pressure Reference= 18 psig. ISTB-3510(b)(1) maximum Range= 3x Reference= 54 psig
Turkey Point Nuclear Plant Docket Nos. 50-250 and 50-251 L-2024-066 Enclosure Page 3 of 3 Table 1, Comparison of Pressure Instrument Ranges and Accuracies, cont.
Discharge Pressure Gauge Range Accuracy Discharge Pressure Inaccuracy Turkey Point 0 - 600 psig 0.25%
1.5 psig Group A 0 - 480** psig 2.0%
9.6 psig
- Discharge Pressure Reference= 160 psig. ISTB-3510(b)(1) maximum Range= 3x's Reference
= 480 psig Combination - Differential Pressure Suction Suction Pressure Discharge Discharge Total Pressure Gauge Range Accuracy Gauge Range Accuracy Inaccuracy Turkey Point 0 - 600 psig 0.25% (1.5 psig) 0 - 600 psig 0.25% (1.5 psig) 3.0 psig
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Group A 0 - 54 psig 2.0% (1.1 psig)
O - 480 psig 2.0% (9.6 psig) 10.7 psig Duration of Proposed Alternative The proposed alternative will be utilized for the entire Sixth 120-month 1ST Program Interval for Turkey Point Units 3 and 4. The Sixth 10-Year Interval start dates are February 22, 2025 for Unit 3 and April 15, 2025 for Unit 4.
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Precedents
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Nuclear Regulatory Commission (NRC) letter to NextEra Energy Nuclear Division, "Turkey Point Nuclear Generating Unit Nos. 3 and 4 - Safety Evaluation for Relief Request No. PR-02, for the Fifth 10-Year lnservice Testing Interval Regarding Requirements for the Quarterly Testing of the Residual Heat Removal Pumps (CAC NOS. MF6388 AND MF6389)," January 22, 2016 (ADAMS Accession No. ML16011A205).
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NRC letter to NextEra Energy Nuclear Division, "Turkey Point Nuclear Generating Unit Nos. 3 and 4 - Safety Evaluation for Relief Request No. PR-01, for the Fifth 10-Year lnservice Testing Interval Regarding Requirements for the Quarterly Testing of the Boric Acid Transfer Pumps (CAC NOS. MF6252 AND MF6253)," December 9, 2015 (ADAMS Accession No. ML042820470).
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NRC letter to First Energy Nuclear Operating Company, "Beaver Valley Power Station, Unit No.
1 - Requests for Alternatives and Requests for Relief Re: Fifth 10-Year lnservice Testing Program Interval (CAC Nos. MF8332, MF8334, MF8336, MF8337, MF8340, MF8342, MF8344, MF8346, MF8348, MF8350, MF8351, MF8353, MF8354, MF8355, and MF8357)," June 26, 2017 (ADAMS Accession No. ML17159A442).