L-2015-224, Fifth Ten-Year Interval Inservice Testing (IST) Program, Relief Request No. PR-02
| ML15299A350 | |
| Person / Time | |
|---|---|
| Site: | Turkey Point  |
| Issue date: | 09/25/2015 |
| From: | Summers T Florida Power & Light Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| L-2015-224 | |
| Download: ML15299A350 (6) | |
Text
0SEP 2 52015 F=PLo L-2015-224 10 CFR 50.55a U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555 RE:
Florida Power and Light Company Turkey Point Units 3 and 4 Docket Nos. 50-250 and 50-251 Fifth Ten-Year Interval Inservice Testing (IST) Program Relief Request No. PR-02 Pursuant to 10 CFR 50.55a (f)(5)(iii), Florida Power & Light (FPL) hereby requests approval of the attached Relief Request No. PR-02, for the Fifth Ten-Year Interval Inservice Testing Program.
This letter supersedes the previous submittal of this relief request, which was provided in FPL letter L-2015-099 dated June 10, 2015 (ADAMS accession number ML15188A030).
FPL requests relief from the instrument range requirements of the American Society of Mechanical Engineers (ASME) Code for Operation and Maintenance of Nuclear Power Plants (OM Code),
Section ISTB-35 10(b)(1), which require that the full scale range of each analog instrument do not exceed three times the reference value. Relief is requested for the Turkey Point Units 3 and 4 suction and discharge pressure instruments for the Residual Heat Removal (RHR) pumps during the quarterly testing. This relief is requested on the basis that compliance with the specified Code requirement is impractical. Specifically, compliance with the requirements of ISTB-3 510O(b)( 1) is impractical because it would require system modifications and installation of new instrumentation to meet the allowed range of three times the reference value.
If you have any questions or require additional information, please contact Mr. Mitch Guth, Licensing Manager, at (305) 246-6698.
Sincerely, thomas Summers Site Vice President Turkey Point Nuclear Plant Attachment cc:
Regional Administrator, Region II, USNRC Senior Resident Inspector, USNRC, Turkey Point Plant Florida Power
- Light Company 9760 S.W. 344u Street Homeste-ad, FL 33035
L-20 15-224 Attachment Page 1 of 5 Inservice Testing Program Relief Request No. PR-02 Turkey Point Units 3 and 4 Residual Heat Removal Pump Suction and Discharge Pressure Gauges In Accordance with 10 CFR 50.55a (f)(5)(iii)
Inservice Testing Impracticality
- 1. ASME Code Components Affected 3P2 10A 3A Residual Heat Removal Pump 3P2 10B 3B Residual Heat Removal Pump 4P2 10A 4A Residual Heat Removal Pump 4P2 10B 4B Residual Heat Removal Pump
- 2.
Applicable Code and Addenda The Fifth Ten-Year Interval commenced on February 22, 2015, and on Aprit 15, 2015 for Turkey Point Units 3 and Unit 4, respectively.
The Code of Record for the Turkey Point Units 3 and 4, Fifth Ten-Year Interval Inservice Testing (1ST) Program is the 2004 Edition with the 2005 and 2006 Addenda of the American Society of Mechanical Engineers (ASME) Code for Operation and Maintenance of Nuclear Power Plants (OM Code).
- 3.
Applicable Code Requirement
ASMIE OM Code ISTB-3510(b)(1), 2004 Edition with the 2005 and 2006 Addenda - The full-scale range of each analog instrument shall not be greater than three times the reference value.
- 4.
Impracticality of Compliance For Group A and Group B tests, the Code requires instrument accuracy to be within 2% of full-scale and the full scale range of each instrument to be no greater than three times the reference value.
At Turkey Point the Residual Heat Removal Pumps (RHIR) 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 0 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.
L-20 15-224 Attachment Page 2 of 5 Florida Power & Light Company (FPL) requests relief from the instrument range requirements of ISTB-3 510O(b)( 1), which requires that the full scale range of each analog instrument to exceed three times the reference value.
Relief is requested for the suction and discharge pressure instruments for the RHIR pumps during the quarterly testing.
Relief is requested since compliance with the code requirements would require system modifications and installation of new instrumentation to meet the allowed range of three times the reference value would therefore, be considered impractical.
- 5.
Burden Caused by Compliance Compliance with the requirements of ISTB-3 510O(b)( 1) is impractical because it would require system modifications and installation of new instrumentation to meet the allowed range of three times the reference value.
- 6.
Proposed Alternative and Basis for Use As an alternative, FPL is proposing to use the existing Turkey Point RHR Pump instrumentation, without meeting the requirements of ISTB-35 10(b)(1), but which exceed the Code required accuracies that will be applied to Group A quarterly tests of the RHIR pumps. This relief request does not apply to the comprehensive RHIR pump testing.
Table 1 presents a comparison between the permanently installed pressure gauges on the RHIR pumps along with the Code required ranges and accuracies for both Group A quarterly tests.
Figure 1 presents the existing RIHR Suction and Discharge Pressure Gauge to be used. These 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 Residual Heat Removal operations (Shutdown Cooling and Emergency Core Cooling). The instrument range on the first revolution is 0 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 or no 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 RHIR 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 0 to 54 p sig. The Code accuracy requirement of 2% would cause a maximum inaccuracy of 2.0% x 60 psig, or 1.1 psig, as presented in Table 1.
L-20 15-224 Attachment Page 3 of 5 Discharge Pressure Discharge pressure measurements are also recorded and used to derive the pump differential pressure through calculation. When determining pump differential pressure (DP), typically the RHIR pump DP is approximately 142 psig (discharge pressure approximately 160 psig while suction pressure is approximately 18 psig).
The maximum effect of the discharge pressure inaccuracies is 0.25% x 600 psig, or 1.5 psig. The Code required gauge range for this discharge pressure reference value (160 psig) would be 0 to 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 1.
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.
Based on the overall instrument inaccuracies, the proposed alternative to use the permanently installed pressure instrumentation provides reasonable assurance that the residual heat removal pumps are operationally ready.
- 7.
Duration of Proposed Alternative This proposed alternative will be utilized for the duration of the Fifth Ten Year Inservice Testing Interval for Turkey Point Units 3 and 4. The Fifth Ten-Year Interval start dates are February 22, 2015 for Unit 3 and April 15, 2015.
- 8.
Precedents A similar relief request was previously approved for the Fourth Ten Year Inservice Testing Interval at Turkey Point (ML042820470).
L-20 15-224 Attachment Page 4 of 5 Turkey Point Units 3 and 4 Inservice Testing Proaram Relief Request No. PR-02 Table 1 Comparison of Pressure Instrument (Gauge) Ranges and Accuracy Suction Pressure Gauge Range 0 -600 psig 0 - 54psig Accuracy 0.25 %
2.0 %
Suction Pressure Inaccuracy 1.5 psig 1.1 psig Turkey Point Group A Discharge Pressure Gauge Range 0 -600 psig 0 -480 psig Accuracy 0.25 %
2.0 %
Discharge Pressure Inaccuracy 1.5 psig 9.6 psig Turkey Point Group A Combination - Differential Pressure Suction Suction Gauge Pressure Range Accuracy Turkey Point 0 - 600 psig 0.25 % (1.5 psig)
Group A 0 -54 psig 2.0 % (1.1 psig)
Discharge Gauge Range 0 - 600 psig 0- 480 psig Discharge Pressure Accuracy 0.25 % (1.5 psig) 2.0 % (9.6 psig)
Total Inaccuracy 3.0 psig 10.7 psig
it L-201 5-224 Attachment Page 5 of 5 Turkey Point Units 3 and 4 lnservice Testini8 Proszram Relief Request No. PR-02 Figure 1 RHR Suction and Discharge Pressure Gauge