L-12-138, CFR 50.55a Requests RP-2 and RP-4 Regarding Inservice Pump Testing
| ML121000277 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 04/09/2012 |
| From: | Allen B FirstEnergy Nuclear Operating Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| L-12-138 | |
| Download: ML121000277 (7) | |
Text
FENOC 5501 North State Route 2 FirstEnergy Nuclear Operating Company Oak Harbor, Ohio 43449 Barry S. Allen 419-321-7676 Vice President - Nuclear Fax: 419-321-7582 April 9,2012 L-12-138 10 CFR 50.55a ATTN: Document Control Desk US Nuclear Regulatory Commission Washington, D.C. 20555-0001
Subject:
Davis-Besse Nuclear Power Station, Unit No.1 Docket No. 50-346, License No. NPF-3 10 CFR 50.55a Requests RP-2 and RP-4 Regarding Inservice Pump Testing Pursuant to 10 CFR 50.55a, FirstEnergy Nuclear Operating Company (FENOC) hereby requests Nuclear Regulatory Commission (NRC) approval of 10 CFR 50.55a requests RP-2 and RP-4 for the Davis-Besse Nuclear Power Station, Unit No.1, fourth ten-year inservice testing program for pumps and valves. Requests RP-2 and RP-4 are for the component cooling water pumps and service water pumps, respectively, and propose the use of pump reference curves to compare flow rate with developed head in lieu of performing each test at the same flow rate. The requests are provided with this letter as enclosures.
FENOC requests approval of RP-2 and RP-4 by September 12,2012. Expedited review and approval is needed because testing could be required at the beginning of the inservice test interval (due to changes in the quarterly pump test schedule), and the design of systems associated with the affected pumps does not allow for pump testing at a single reference point.
There are no regulatory commitments contained in this letter. If there are any questions or if additional information is required, please contact Mr. Phil H. Lashley, Supervisor - Fleet Licensing, at (330) 315-6808.
Sincerely,
~ar Barry S. Allen
Davis-Besse Nuclear Power Station L-12-138 Page 2 of 2
Enclosures:
A. 10 CFR 50.55a Request Number: RP-2 B. 10 CFR 50.55a Request Number: RP-4 cc: NRC Region III Administrator NRC Project Manager NRC Resident Inspector Executive Director, Ohio Emergency Management Agency, State of Ohio (NRC Liaison)
Utility Radiological Safety Board
10 CFR 50.55a Request Number: RP-2 Proposed Alternative in Accordance with 10 CFR 50.55a(a)(3)(i)
Page 1 of 3
--Alternative Provides Acceptable Level of Quality and Safety--
- 1. ASME Code Components Affected P43-1, Component Cooling Water Pump, Class 3, Group A P43-2, Component Cooling Water Pump, Class 3, Group A P43-3, Component Cooling Water Pump, Class 3, Group A
2. Applicable Code Edition and Addenda
American Society of Mechanical Engineers Code for Operation and Maintenance of Nuclear Power Plants (ASME OM Code), 2004 Edition through 2006 Addenda.
- 3. Applicable Code Requirements Subparagraph IST8-5121 (b), of the ASME OM Code states in part that:
The resistance of the system shall be varied until the flow rate equals the reference point. The differential pressure shall then be determined and compared to the reference value.
Subparagraph IST8-5121 (d), of the ASME OM Code states in part that:
Vibration (displacement or velocity) shall be determined and compared with the reference value.
4. Reason for Request
The component cooling water system was not designed with installed pump test lines.
To achieve the same operating point for each test, manual butterfly valves, which are not designed to throttle flow, would be used. Repeatability of test results when using these valves to throttle flow is poor. Depending on plant operating and climatic conditions, the cooling requirements range from minimum cooling loads (approximately 3000 gallons per minute [gpmD to 100 percent (approximately 8000 gpm). System operating conditions do not allow adjusting system resistance without significant impact on the plant's thermal stability.
A fixed flow rate through the pump aligned to the essential and non-essential loads cannot be accomplished because system resistances are continuously varying and flows to parallel loads are dependent on each other. Spent fuel cooling and boric acid evaporators have temperature control valves, which vary demand on the component cooling water system according to heat load. Component cooling water flow to the reactor coolant pump seal coolers varies dependent on the throttle valve positions on the supply lines for the four pumps. Component cooling water flow to the control rod drive stators passes through filters whose flow will change dependent on filter loading.
- 5. Proposed Alternative and 8asis for Use Pump reference curves, developed per the guidelines in NUREG-1482, Revision 1, Section 5.2, "Use of Variable Reference Values for Flow Rate and Differential Pressure
Davis Besse Nuclear Power Station 10 CFR 50.55a Request RP-2 Page 2 of 3 During Pump Testing," will be used to compare flow rate with developed pump head at the flow conditions dictated by Component Cooling Water System loads each quarter.
Baseline vibration data obtained at various flow points on the pump curve will be used to develop a vibration versus flow curve.
In lieu of using ASME OM Code Case OMN-9, "Use of Pump Curves for Testing" as referenced in Section 5.2 of NUREG-1482, ASME OM Code Case OMN-16, "Use of Pump Curve for Testing" shall be used.
Deviations from the reference curves shall be compared with the ranges of ASME OM Code Table ISTB-5121-1.
Paragraph ISTB-3320, "Establishment of Additional Set of Reference Values," of the ASME OM Code provides for an additional set of reference values. When it is not feasible to test a pump at a reference value of flow and differential pressure, testing in the "as found" condition and comparing values to an established reference curve should be considered an acceptable alternative. Pump curves represent an infinite set of reference points for flow rate and differential pressure. The proposed alternative establishes a reference pump curve when the pump is known to be operating acceptably. Acceptance criteria based on this reference pump curve, permit evaluation of the pump condition and detection of degradation.
Code Case OMN-16 is included in the 2006 Addenda, but has not been included in Regulatory Guide 1.192, "Operation and Maintenance Code Case Acceptability, ASME OM Code," for generic industry use. However, Code Case OMN-9 was conditionally accepted in Regulatory Guide 1.192. The conditions imposed on Code Case OMN-9 as stated in Regulatory Guide 1.192 have been incorporated into Code Case OMN-16. In addition, code applicability for the use of OMN-16 includes ASME OM Code 2004 Edition through 2006 Addenda, which is the fourth 1O-year inservice test interval code of record for Davis-Besse Nuclear Power Station.
Using the provisions of this relief request as an alternative to the requirements of ASME OM Code subparagraphs ISTB-5121 (b) and ISTB-5121 (d) provides a reasonable alternative to the Code requirements for detecting pump degradation. The proposed alternative method for monitoring the component cooling water pumps for degradation provides an acceptable level of quality and safety, and assurance that the pumps are operationally ready and capable of performing their safety function.
- 6. Duration of Proposed Alternative The duration of the proposed alternative is the fourth 10-year Inservice Test Interval (September 21, 2012 to September 20, 2022).
- 7. Precedent The NRC staff found that ASME OM Code Case OMN-16 is an acceptable replacement for ASME OM Code Case OMN-9 in an evaluation of request P-4 involving component cooling water pumps at North Anna Power Station. The component cooling water system at North Anna Power Station, Unit Nos. 1 and 2, is similar to the component cooling water system at Davis-Besse Nuclear Power Station in that the component cooling water pumps are Group A, Class 3, centrifugal pumps, and reproducing one
Davis Besse Nuclear Power Station 10 CFR 50.55a Request RP-2 Page 3 of 3 specific flow reference point is difficult with the installed butterfly valves and varying plant conditions.
Reference:
Nuclear Regulatory Commission (NRC) Safety Evaluation for North Anna Power Station, Unit Nos. 1 and 2, Fourth 10-Year Inservice Testing Interval Program, Pumps and Valves Relief Request, date September 30, 2010 (Accession Number ML102460223).
A similar pump relief request RP-2 was authorized by the NRC staff for use during the third 10-Year Inservice Test Interval for Davis Besse Nuclear Power Station. The alternative followed the NRC guidelines specified in NUREG-1482, Section 5.2, to develop pump reference curves to compare flow with developed pump head (differential pressure) at the flow conditions dictated by Component Cooling Water System loads each quarter for Group A tests. The letter authorizing the request is cited below.
Nuclear Regulatory Commission Staff Evaluation of Davis-Besse Nuclear Power Station, Unit 1 - Requests For Relief From The Third 10-Year Pump And Valve Inservice Testing (1ST) Program (TAC No. MB3909), dated March 28, 2003, (Accession No. ML030790183).
10 CFR 50.55a Request Number: RP-4 Proposed Alternative in Accordance with 10 CFR 50.55a(a)(3)(i)
Page 1 of 2
--Alternative Provides Acceptable Level of Quality and Safety--
- 1. ASME Code Components Affected P3-1, Service Water Pump, Class 3, Group A P3-2, Service Water Pump, Class 3, Group A P3-3, Service Water Pump, Class 3, Group A
2. Applicable Code Edition and Addenda
American Society of Mechanical Engineers Code for Operation and Maintenance of Nuclear Power Plants (ASME OM Code), 2004 Edition through 2006 Addenda.
The resistance of the system shall be varied until the flow rate equals the reference point. The differential pressure shall then be determined and compared to the reference value.
Subparagraph ISTB-5221 (d) of the ASME OM Code states in part that:
Vibration (displacement or velocity) shall be determined and compared with the reference value.
4. Reason for Request
The service water system is in continuous operation during all modes of plant operation and system flow varies with the temperature requirement of the various safety and non-safety related loads. The system was not designed with installed pump test lines.
System operating conditions do not allow adjusting system resistance without significant impact on the plant's thermal stability. Depending on plant operating and climatic conditions, the cooling requirements range from minimum cooling loads (approximately 6000 gallons per minute [gpmD to 100 percent (approximately 10000 gpm). Many of the system loads are automatically placed in operation in response to local temperature requirements. Operating experience has shown that plant conditions preclude setting the service water pumps to the exact flow rate for a specific reference value, due to heat loads that require cooling by the service water system.
- 5. Proposed Alternative and Basis for Use Pump reference curves (developed per the guidelines in NUREG-1482, Revision 1, Section 5.2, "Use of Variable Reference Values for Flow Rate and Differential Pressure During Pump Testing") will be used to compare flow rate with developed pump head at the flow conditions dictated by service water system loads each quarter. Baseline vibration data obtained at various flow points on the pump curve will be used to develop a vibration versus flow curve.
Davis Besse Nuclear Power Station 10 CFR 50.55a Request RP-4 Page 2 of 2 In lieu of using ASME OM Code Case OMN-9, "Use of Pump Curves for Testing" as referenced in Section 5.2 of NUREG-1482, ASME OM Code Case OMN-16, "Use of Pump Curve for Testing" shall be used.
Deviations from the reference curves shall be compared with the ranges of ASME OM Code Table ISTB-5221-1.
Paragraph ISTB-3320, "Establishment of Additional Set of Reference Values," of the ASME OM Code provides for an additional set of reference values. When it is not feasible to test a pump at a reference value of flow and differential pressure, testing in the "as found" condition and comparing values to an established reference curve should be considered an acceptable alternative. Pump curves represent a set of infinite reference points of flow rate and differential pressure. The proposed alternative establishes a reference pump curve when the pump is known to be operating acceptably. Acceptance criteria based on this reference pump curve, permit evaluation of the pump condition and detection of degradation.
Code Case OMN-16 is included in the 2006 Addenda, but has not been included in Regulatory Guide 1.192, "Operation and Maintenance Code Case Acceptability, ASME OM Code," for generic industry use. However, Code Case OMN-9 was conditionally accepted in Regulatory Guide 1.192. The conditions imposed on Code Case OMN-9 as stated in Regulatory Guide 1.192 have been incorporated into Code Case OMN-16. In addition, Code applicability for the use of OMN-16 includes ASME OM Code 2004 Edition through 2006 Addenda, which is the fourth 1O-year inservice test interval code of record for Davis-Besse Nuclear Power Station.
Using the provisions of this relief request as an alternative to the requirements of ASME OM Code subparagraphs ISTB-5221 (b) and ISTB-5221 (d) provides a reasonable alternative to the Code requirements. The proposed alternative method of monitoring the service water pumps for degradation provides an acceptable level of quality and safety, and assurance that the pumps are operationally ready and capable of performing their safety functions.
- 6. Duration of Proposed Alternative The duration of the proposed alternative is the fourth 10-year Inservice Test Interval (September 21,2012 to September 20,2022).
- 7. Precedent A similar pump relief request RP-4 was authorized by the Nuclear Regulatory Commission (NRC) staff for use during the third 10-Year Inservice Test Interval for Davis Besse Nuclear Power Station. The alternative followed the NRC guidelines specified in NUREG-1482, Section 5.2, to develop pump reference curves to compare flow with developed pump head at the flow conditions dictated by service water system loads each quarter for Group A tests. The letter authorizing the request is cited below.
Nuclear Regulatory Commission Staff Evaluation of Davis-Besse Nuclear Power Station, Unit 1 - Requests For Relief From The Third 10-Year Pump And Valve Inservice Testing (1ST) Program (TAC No. MB3909), dated March 28, 2003, (Accession No. ML030790183).