ML111751776
| ML111751776 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 06/30/2011 |
| From: | Nancy Salgado Plant Licensing Branch 1 |
| To: | Harden P FirstEnergy Nuclear Operating Co |
| Morgan N, NRR/DORL, 415-1016 | |
| References | |
| TAC ME4385, TAC ME4393 | |
| Download: ML111751776 (16) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 June 30, 2011 Mr. Paul A. Harden Site Vice President FirstEnergy Nuclear Operating Company Beaver Valley Power Station Mail Stop A-BV-SEB 1 P.O. Box 4, Route 168 Shippingport, PA 15077 SUB..IECT: BEAVER VALLEY POWER STATION, UNIT NO.2 - PUMP RELIEF REQUESTS 4 AND 10 REGARDING THE SERVICE WATER PUMP TESTING RELIEF REQUESTS PRR4 AND PRR10 (TAC NOS. ME4385 AND ME4393)
Dear Mr. Harden:
By letter dated July 22, 2010, as supplemented by letter dated December 22, 2010, FirstEnergy Nuclear Operating Company (the licensee) requested authorization of proposed alternatives to certain requirements associated with the inservice testing (1ST) program at Beaver Valley Power Station, Unit No.2 (BVPS-2) for the remainder of the third 10-year 1ST program interval, which began on November 18, 2007 and ends on November 17, 2017. Specifically, the licensee requested relief from the American Society of Mechanical Engineers (ASME) Code for Operation and Maintenance of Nuclear Power Plants (OM Code) requirements of ISTB-5221, ISTB-5221(b), ISTB-5223 , and ISTB-5223(b) for service water (SW) pumps 2SWS*P21A, 2SWS*P21B, and 2SWS*P21C in Pump Relief Request 4 (PRR4). In PPR10, the licensee requested relieffrom the ASME OM Code requirements of ISTB-5221 (e), and ISTB-5223(e) for SW pumps 2SWS*P21A, 2SWS*P21B, and 2SWS*P21C.
The Nuclear Regulatory Commission (NRC) staff has concluded that it is impractical for the licensee to comply with certain requirements of the ASME OM Code for SW pumps 2SWS*P21A, 2SWS*P21B, and 2SWS*P21C testing. The proposed testing methods and acceptance criteria specified in PRR4 and PRR10 provide reasonable assurance that the SW pumps will remain operationally ready. Therefore, pursuant to Section 50.55a(f)(6)(i) of Part 50 of Title 10 of the Code of Federal Regulations, granting relief for PRR4 and PRR10 is authorized by law and will not endanger life or property or the common defense and security, and is otherwise in the public interest, giving due consideration to the burden upon the licensee that could result if the ASME OM Code requirements were imposed on the facility. The NRC staff grants relief for the remainder of the BVPS-2 third 10-year 1ST program interval, which began on November 18,2007 and ends on November 17,2017.
All other ASME OM Code requirements for which relief was not specifically requested and approved in the subject request for relief remain applicable.
P. Harden If you have any questions, please contact the Beaver Valley Project Manager, Nadiyah Morgan, at (301) 415-1016.
Sincerely, 7f~£7/ ~~
Nancy L. Salgado, Chief Plant Licensing Branch 1-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-412
Enclosure:
As stated cc w/encl: Distribution via Listserv
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION REGARDING ALTERNATIVE TO THE INSERVICE TESTING PROGRAM FIRSTENERGY NUCLEAR OPERATING COMPANY FIRSTENERGY NUCLEAR GENERATION CORP.
OHIO EDISON COMPANY THE TOLEDO EDISON COMPANY BEAVER VALLEY POWER STATION, UNIT NO.2 DOCKET NO. 50-412
1.0 INTRODUCTION
By letter dated July 22,2010 (Agencywide Document Access and Management System (ADAMS) Accession No. ML102090021), as supplemented by letter dated December 22,2010 (ADAMS Accession No. ML103620451), FirstEnergy Nuclear Operating Company (the licensee) requested authorization of proposed alternatives to certain requirements associated with the inservice testing (1ST) program at Beaver Valley Power Station, Unit No.2 (BVPS-2) for the remainder of the third 10-year 1ST program interval, which began on November 18, 2007 and ends on November 17, 2017. Specifically, the licensee requested relief from the American Society of Mechanical Engineers (ASME) Code for Operation and Maintenance of Nuclear Power Plants (OM Code) requirements of ISTB-5221, ISTB-5221(b), ISTB-5223, and ISTB 5223(b) for service water (SW) pumps 2SWS*P21A, 2SWS*P21 B, and 2SWS*P21 C in Pump Relief Request 4 (PRR4). In PPR1 0, the licensee requested relief from the ASME OM Code requirements of ISTB-5221 (e), and ISTB-5223(e) for SW pumps 2SWS*P21A, 2SWS*P21 B, and 2SWS*P21C.
2.0 REGULATORY EVALUATION
Section 50.55a(f) of Part 50 of Title 10 of the Code of Federal Regulations (10 CFR), "Inservice Testing Requirements," requires, in part, that 1ST of certain ASME Class 1,2, and 3 pumps and valves are performed in accordance with the specified ASME Code and applicable addenda incorporated by reference in the regulations. Exceptions are allowed where alternatives have been authorized or relief has been requested by the licensee and granted by the NRC pursuant to paragraphs (a)(3)(O, (a)(3}(ii), or (f)(6)(i) of 10 CFR 50.55a. In proposing alternatives or requesting relief, the licensee must demonstrate that: (1) the proposed alternatives provide an acceptable level of quality and safety (10 CFR 50.55a(a)(3)(i>>; (2) compliance would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety Enclosure
- 2 (10 CFR 50.55a(a)(3)(ii)); or (3) conformance is impractical for the facility (10 CFR 50.55a(f)(6)(i)). Section 50.55a allows the NRC to authorize alternatives and to grant relief from ASME OM Code requirements upon making necessary findings. In accordance with 10 CFR 50.55a(f)(4)(ii), licensees are required to comply with the requirements of the latest edition and addenda of the ASME Code incorporated by reference in the regulations 12 months prior to the start of each 120-month 1ST program interval. In accordance with 10 CFR 50.55a(f)(4)(iv), 1ST of pumps and valves may meet the requirements set forth in subsequent editions and addenda that are incorporated by reference in 10 CFR 50.55a(b), subject to NRC approval. Portions of editions or addenda may be used provided that all related requirements of the respective editions and addenda are met. NRC guidance contained in Generic Letter (GL) 89-04, "Guidance on Developing Acceptable Inservice Testing Programs," provides alternatives to ASME Code requirements which are acceptable. Further guidance is given in GL 89-04, Supplement 1, and NUREG-1482 Revision 1, "Guidelines for Inservice Testing at Nuclear Power Plants." ASME OM code cases that are approved for use by the NRC are listed in Regulatory Guide (RG) 1.192, "Operation and Maintenance Code Case Acceptability, ASME OM Code" dated June 2003 (10 CFR 50.55a(b)(6)).
3.0 TECHNICAL EVALUATION
3.1 PRR4 3.1.1 System/Component Affected 2SWS*P21A - SW pump 2SWS*P21 B - SW pump 2SWS*P21C - SW pump 3.1.2 Applicable Code Requirements The Code of record for the BVPS-2 third 1O-year 1ST program interval is ASME OM Code, 2001 Edition, with Addenda through OMb-2003, as required by 10 CFR 50.55a(f)(4)(ii).
ISTB-3320, "Establishment of Additional Set of Reference Values," states, in part, that "If it is necessary or desirable, for some reason other than stated in ISTB-3310, to establish an additional set of reference values, a Group A or comprehensive test shall be run at the conditions of an existing set of reference values and analyzed."
ISTB-5221, "Group A Test Procedure," states, in part, that "Group A tests shall be conducted with the pump operating at a specified reference point."
ISTB-5221 (b) states that, "The resistance of the system shall be varied until the flow rate equals the reference point. The differential pressure (liP) shall then be determined and compared to its reference value. Alternatively, the flow rate shall be varied until the liP equals the reference point and the flow rate determined and compared to the reference flow rate value."
ISTB-5223, "Comprehensive Test Procedure," states, in part, that, "Comprehensive tests shall be conducted with the pump operating at a specified reference point."
~ 3~
ISTB~5223(b) states that, "The resistance of the system shall be varied until the flow rate equals the reference point. The LlP shall then be determined and compared to its reference value.
Alternatively, the flow rate shall be varied until the LlP equals the reference point and the flow rate determined and compared to the reference flow rate value."
ASME OM Code Case OMN-9, "Use of a Pump Curve for Testing," states, in part, that "If it is necessary or desirable, for some reason other than stated in section 4 above, to establish an additional set of reference values or reference curves, an inservice test shall be run at the conditions of an existing set of reference values, or within the range of existing reference curves, and the results analyzed."
3.1.3 Licensee's Proposed Alternative and Basis for Use The licensee requested relief from the requirements of ISTB-5221, ISTB-5221 (b), ISTB~5223, and ISTB~5223(b) for SW pumps 2SWS*P21A, 2SWS*P21 B, and 2SWS*P21 C. In lieu of these requirements, the licensee proposes to develop and use a pump curve in accordance with the guidelines of Code Case OMN-9 for testing of these SW pumps. In PRR4, the licensee stated:
Operating experience has shown that plant conditions due to head loads requiring cooling by the [SW] system may preclude returning the [SW] pumps to the exact flow rate or [LlP] during pump surveillance testing. The [SW] system is dependent on seasonal Ohio River water temperatures and flow may vary from approximately 6,000 gallons per minute (gpm) in the cool winter months to approximately 14,000 gpm in the warm summer months.
In order to increase flow to a reference value during the cold winter months, idle heat exchangers would need to be placed into service or additional flow would be needed through heat exchangers already in service. Increased cooling flow through primary and secondary component cooling and chiller unit heat exchangers already in service could result in a thermal transient and a potential plant trip. Clean heat exchangers may require placement into service prematurely if additional flow is required to return to a reference value. Idle heat exchangers are normally held in reserve following cleaning to improve plant reliability and safety until one of the inservice heat exchangers becomes fouled.
In order to throttle flow to a reference value during warm summer months, any inservice primary and secondary component cooling and chiller unit heat exchangers would need [their] flow reduced or isolated, which could interrupt flow of cooling water to Train A or Train B cooling loads resulting in a thermal transient and potential plant trip. In addition, the added thermal cycling due to placement or removal of heat eXChangers from service for pump testing could prematurely degrade the heat exchangers.
The thermal transients created by increa3ing or throttling [SW] system flow to the turbine plant cooling loads could result in stability problems. Changes in oil temperature from the turbine generator lube oil system could create vibration problems. Changes in the hydrogen gas cooler temperatures could imply problems or mask real problems with the generator. Chiller unit heat exchanger
-4 flow disturbances could result in a trip of the chiller unit that may cause reactor containment temperature to exceed the technical specification limit.
The licensee proposed to develop a pump curve in accordance ASME OM Code Case OMN-9.
This pump curve will be used to compare the flow rate with the developed pump head at the flow conditions dictated by plant seasonal heat load requirements in accordance with the SW pump testing procedures during each quarterly Group A test and biennial Comprehensive test.
The licensee stated, "Since normal flow varies, the most limiting vibration acceptance criteria will be used over this range of flows based on baseline vibration data obtained at various flow points on the pump curve."
ISTB-3320 provides for multiple sets of reference values. The licensee stated, "A pump curve is consistent with this Code section, since it is merely is a graphical representation of the fixed response of the pump to an infinite number of flow conditions that are based on a finite number of reference values verified by measurement. Flow will be permitted to vary as system conditions require. Differential pressure will be calculated and converted to a developed head for the ranges included in Table ISTB-S200-1."
3.1.4 NRC Staff's Evaluation The licensee requested relief from ASME OM Code Paragraphs ISTB-S221, ISTB-S221 (b),
ISTB-S223, and ISTB-S223(b) for SW pumps 2SWS*P21A, 2SWS*P21B, and 2SWS*P21C.
These paragraphs state that the Group A and Comprehensive tests shall be conducted with the pump operating at a specified reference pOint. The resistance of the system shall be varied until the flow rate equals the reference pOint. The ~P shall then be determined and compared to its reference value. Alternatively, the flow rate shall be varied until the ~P equals the reference point and the flow rate determined and compared to the reference flow rate value.
The licensee proposed to use ASME OM Code Case OMN-9 for these pumps for the remainder of its third 10-year 1ST program interval. Code Case OMN-9 allows the use of pump curve(s) for 1ST of pumps. Code Case OMN-9 applies to the ASME OM Code 1990 Edition through the 1992 Addenda. The licensee's 1ST program is based on the 2001 Edition through the 2003 addenda of the OM Code.
Application of Code Case OMN-9 is addressed in 10 CFR SO.SSa(b)(6) and reference in RG 1.192, which lists acceptable and conditionally acceptable code cases for implementation in 1ST programs. RG 1.192, Table 2, approves with caveats, the use of Code Case OMN-9. The caveats are as follows; (1) When a reference curve may have been affected by repair, replacement, or routine servicing of a pump, a new reference curve must be determined, or an existing reference curve must be reconfirmed, in accordance with Section 3 of this Code Case.
(2) If it is necessary or desirable, for some reclson other than that stated in Section 4 of this Code Case, to establish an additional reference curve or set of curves, these new curves must be determined in accordance with Section 3.
-5 In July 2006, the ASME OM Committee approved the elimination of all code case expiration dates. They stated that any published code case that has not been annulled, and that has an expiration date that is after July 2006 is not expired and may continue to be used. There is no technical reason for prohibiting the use of Code Case OMN-9 with the 200'1 Edition through 2003 Addenda of the OM Code. Therefore, use of Code Case OMN-9, including the caveats listed in Table 2 of RG 1.192, is consistent with RG 1.192 and the ASME OM Code, and provides an acceptable level of quality and safety for pump testing.
In the case of SW pumps 2SWS*P21A, 2SWS*P21 B, and 2SWS*P21 C, it would be impractical to throttle the system in order to achieve a fixed reference value as resistance is varied in response to the heat loads of the plant, which are seasonally dependent and can vary significantly. Varying the flow rates presents the potential for loss of adequate or excessive flow and cooling to the heat exchangers. Therefore, the NRC staff has determined that trying to meet the ASME OM code fixed reference values represents an impractical condition.
3.2 PRR10 3.2.1 System/Component Affected 2SWS*P21A - SW pump 2SWS*P21 B - SW pump 2SWS*P21 C - SW pump 3.2.2 Applicable Code Requirements The Code of record for the BVPS-2 third 1O-year 1ST program interval is ASME OM Code, 2001 Edition, with Addenda through OMb-2003, as required by 10 CFR 50.55a(f)(4)(ii).
ISTB-5221 (e), "Group A Test Procedure," states, in part, that "All deviations from the reference values shall be compared with the ranges of Table ISTB-5200-1."
ISTB-5223(e), "Comprehensive Test Procedure," states, in part, that "All deviations from the reference values shall be compared with the ranges of Table ISTB-5200-1."
3.2.3 Licensee's Proposed Alternative and Basis for Use The licensee requested relief from the requirements of ISTB-5221 (e), and ISTB-5223(e) for SW pumps 2SWS*P21A, 2SWS*P21 B, and 2SWS*P21 C. In lieu of these requirements, the licensee proposed to use expanded test acceptance criteria ranges from what is in Table ISTB-5200-1, "Vertical Line Shaft and Centrifugal Pumps Test Acceptance Criteria," when the river water temperature is above 60 degrees Fahrenheit CF).
In PRR10, the licensee stated:
The [SW] system operation is dependent on seasonal Ohio River water temperatures with pump flow rates varying between approximately 6,000 [gpm] in the cool winter months to approximately 14,000 gpm in the warm summer months. Due to variations in pump flow rate and [~P] (pump head), and as
-6 months. Due to variations in pump flow rate and [8P] (pump head), and as requested in PRR4, a pump curve will be used to compare flow rate with developed pump head at the flow conditions dictated by plant seasonal heat load requirements. The Group A and Comprehensive pump test acceptance criteria for [8P] are provided in Table ISTB-5200-1 for vertical line shaft pumps. The developed head of a pump is calculated by multiplying the [8P] by 2.31 feet/pounds per square inch.
The Table ISTB-5200-1 8P acceptance criteria are as follows:
For Group A Tests, the Acceptable Range is 0.95 to 1.108Pr , the Alert Range is 0.93 to
<0.958P r, and the Required Action Range is <0.93llPr and >1.10llP r.
For Comprehensive Tests. the Acceptable Range is 0.95 to 1.038Pr
- the Alert Range is 0.93 to
<0.958Pr , and the required Action Range is <0.938Pr and >1.038P r .
The subscript r denotes "reference value."
The [SW] pumps are typically overhauled in the colder winter months when the demand on the [SW] system for cooling is less. The reference pump curve is developed during this time period. The [SW] pump shaft is made from stainless steel and the pump columns are made from carbon steel. As river water temperature increases, the stainless steel shaft expands at a different rate than the carbon steel columns [5.9 x 10-6 inch/inchrF versus 6.4 x 10-6 inch/inchfOF]
resulting in a net change in the clearance at the impeller. Because the carbon steel columns grow slightly more than the stainless steel shaft. a wider gap between the impeller and bowl is created, which causes an increase in pump lift.
This results in lower hydraulic performance from the reference pump curve. As river water temperature rises above 60 [OF], pump hydraulic performance decreases, sometimes into the alert range of 0.93 to <0.95llPr* As river water temperature begins to cool again, pump hydraulic performance tends to return to the original cold weather reference value. [This can be seen on the trend plots in the attachment to the SE that were developed for the three SW pumps. The trend plots use head ratio, which is calculated by dividing the developed head of the pump obtained during testing by the head from the pump curve at the tested flow value.] This results in a ratio that would be above or below the pump curve at the tested value.
A pump curve could not be developed [in the summer to accommodate river water temperatures above 60°F due to limits on pump flows during the summer months.] In 2008, [the licensee] attempted to obtain a summer pump curve for
[SW] pump [2SWS*P21 C]. However, the range of flows was limited between approximately 11,700 to 13,300 [gpm] to avoid low [SW system] header pressure at high flow rates (two [SW pumps] running at high flow rates with the system cross-connected downstream can lower [SW system] header pressure significantly), and limited SW system cooling to the primary and secondary component cooling water [CCW] heat exchangers. The primary and secondary
[CCW] cools the reactor coolant pumps and main generator auxiliaries, among
-7 summer increases the potential of overheating plant components, which increases the risk of a plant trip.
Therefore, the ASME OM Code limits of Table ISTB-5200-1 can be too restrictive for the [SW] pumps when the river water temperature is above 60°F. Historical variations in pump head have caused the pumps to enter the alert range and require double frequency testing of the pumps when real degradation has not occurred. An allowable variation larger than these ranges is needed for both the Group A and Comprehensive pump tests, as applicable, in order to trend pump performance. NUREG-1482, "Guidelines for Inservice Testing at Nuclear Power Plants," Revision 1, Section 5.6, "Operability Limits of Pumps," states that if expanded ranges are needed, relief must be obtained. Furthermore, the request for relief must include the licensee's basis for the expanded ranges and the basis for finding that the pump performance does not demonstrate degrading conditions. The basis for acceptable pump performance pertains to the pump and not the system, though pump performance must meet system requirements to remain in an analyzed condition.
The licensee proposed to use expanded ranges for the SW pumps during the Group A and Comprehensive tests when the river water temperature is above 60°F in lieu of the acceptance criteria specified in Table ISTB-5200-1.
The proposed expanded ranges to be used during both the Group A and Comprehensive tests, as modified for Hr, are as follows:
For the Group A tests, the Acceptable Range will be 0.93 to 1.1 OH r, the Alert Range will be 0.90 to <0.93Hr, and the Required Action Range will be <0.90Hr and >1.1 OH r.
For the Comprehensive Tests, the Acceptable Range will be 0.93 to 1.03H r, the Alert Range will be 0.90 to <0.93Hr, and the Required Action Range will be <0.90Hr and >1.03H r.
The subscript r denotes "reference value."
Group A and Comprehensive pump testing will be performed in accordance with the [SW] pump test procedures using the expanded ranges when river water temperature is above 60°F. These expanded ranges will still allow degrading conditions to be identified without needlessly placing the [SW] pump on double frequency testing and will provide assurance that the [SW] pumps will be capable of fulfilling their safety functions.
Decreasing the lower limit of the Acceptable Range to 0.9~1, the Alert Range to 0.90, [and the lower side of the Required Action Range to <0.90] is consistent with lower range limits required by the [1983 Edition ofthej ASME Boiler and Pressure Vessel Code,Section XI, Table IWP-31 00-2, [whlch were once used for the lower limits for these pumps year round.] Currently, there are several feet of margin below the proposed lower Required A;~tion Range Umit of 0.90 to the minimum operating point (MOP) curve for each pump. [SW] Pump, 2SWS*P21A, has 16.1 feet (6.74%) of margin to the MOP curve. [SWJ Pump, 2SWS*P21 B,
-8 has 21.5 feet (8.78%) of margin to the MOP curve. [SW] Pump, 2SWS*P21C, has 11.3 feet (4.85%) of margin to the MOP curve. If pump performance were to degrade in the summer months while river water temperature is above 60°F, enough margin exists above the respective pump's MOP curve to take action before challenging the design basis limits. In addition, once river water temperature decreases below 60°F, the more restrictive ASME OM Code limits from Table ISTB-5200-1 would resume, providing additional margin above the MOP curves.
Other activities are in place that enhance the ability to detect pump degradation.
In addition to measuring vibrations on the upper motor bearing housing as required by the ASME OM Code, vibrations are also measured on the lower motor bearing housing each quarter. Spectral analysis of the vibrations, [which]
is a good practice that can be used to determine the mechanical condition of a pump, [is performed by the licensee on these SW pumps.] Spectral data can provide information to determine if misalignment, unbalance, resonance, looseness, or a bearing problem is present. The trending of the spectral data could also determine a change in condition of the pump. Included in the BVSP-2 preventive maintenance program is a motor lube oil analysis that is performed every 24 weeks, and a complete overhaul of pump and motor that is performed every 516 weeks. The overhaul frequency is based on the expected condition of the pumps as a result of historical overhauls and was established to allow overhaul prior to the point of degradation resulting in questionable operational readiness.
3.2.4 NRC Staff Evaluation The licensee requested relieffor SW pumps 2SWS*P21A, 2SWS*P21B, and 2SWS*P21C from the Code-specified test acceptance criteria for ilP for Group A and Comprehensive tests on the basis that conformance with these tests is impractical. The licensee proposed to test the pumps using expanded ranges for ilP, only when the river water temperature is >60°F.
The Table ISTB-5200-1, ilP acceptance criteria, are as follows:
For Group A Tests, the Acceptable Range is 0.95 to 1.10ilPr , the Alert Range is 0.93 to
<0.95ilP r , and the Required Action Range is <0.93ilP r and >1.1 OilP r .
For Comprehensive Tests, the Acceptable Range is 0.95 to 1.03ilPr , the Alert Range is'0.93 to
<0.95ilP r , and the required Action Range is <0.93ilPr and >1.03ilP r .
The SW system operation is dependent on the seasonal Ohio River water temperatures. The SW pump flow rates vary between approximately 6,000 gpm in the winter months and 14,000 gpm in the summer months. The SW pumps are typically overhauled in the winter months when the demand on the SW system is less. This is time when the SW pump curve is developed. The SW pump shaft and pump columns are made of different materials (stainless steel and carbon steel, respectively). As the river water temperalture increases, the two materials expand at different rates. This results in a net change in the clearance at the impeller.
A wider gap between the impeller and bowl is created, and this causes an increase in pump lift.
- 9 The result is a lower hydraulic performance from the reference pump curve as the river water temperature rises above 60°F. This has resulted in the pumps sometimes entering the alert range during their surveillance test, when the pumps are not actu~ally degrading.
The licensee attempted to develop a second pump reference curve during the summer when the river water temperature was above 60°F, but was unsuccessful because the range of flows was limited to approximately 11,700 to 13,300 gpm in order to avoid low SW system header pressure at high flow rates and limited cooling to the primary and secondary CCW heat exchangers. This reduced cooling increased the risk of a plant trip.
The licensee proposed to use the following expanded ranges for Ule SW pumps when the river water temperature is above 60°F:
For the Group A Tests, the Acceptable Range will be 0.93 to 1.10Hr, the Alert Range will be 0.90 to <0.93Hr. and the Required Action Range will be <0.90Hr and >1.10H r.
For the Comprehensive Tests, the Acceptable Range will be 0.93 to 1.03Hr, the Alert Range will be 0.90 to <0.93Hr, and the Required Action Range will be <0.90Hr and >1.03H r.
These expanded ranges will allow the licensee to identify degrading conditions for the SW pumps without having them enter the Alert Range, resulting in increased frequency pump testing (Le. doubling). The pumps will have from 4.85% to 8.78% margin between the lower Required Action range of 0.90Hr and the MOP on the respective pump curve. Since pump degradation does not normally occur rapidly, this margin would allow the licensee to take action for a degrading pump before challenging the design basis limits.
The licensee also performs other activities to enhance the ability to detect pump degradation.
Vibration measurements are taken on the lower pump motor bearing housing, in addition to the Code-required measurements taking on the upper motor bearing housing, and the licensee performs spectral analysis of the vibration data. Per the BVPS-2 preventive maintenance program, a motor lube oil analysis is performed every 24 weeks, and a complete overhaul of the pump and motor is performed every 516 weeks. The overhaul frequency is based on the expected condition of the pumps as a result of historical overhauls and was established to allow overhaul prior to the point of degradation resulting in questionable operational maintenance.
Licensees must obtain relief if expanded ranges are needed outside of ISTB acceptance criteria, sections. tables, and figures. The relief request must include the licensee's basis for the expanded ranges, as well as the basis for finding that the expanded ranges will identify degraded conditions. Based on this evaluation, the NRC staff has determined that the licensee has included this information in the relief request.
4.0 CONCLUSION
Based on the above evaluation, the NRC staff has concluded that it is impractical for the licensee to comply with certain requirements of the ASME OM Code for SW pumps 2SWS*P21A, 2SWS*P21B, and 2SWS*P21C testing. The proposed testing methods and acceptance criteria specified in PRR4 and PRR10 provide reasonable assurance that the SW pumps will remain operationally ready. Therefore, pursuant to 10 CFR 50.55a(f)(6)(i), granting
- 10 pumps will remain operationally ready. Therefore, pursuant to 10 CFR SO.SSa(f)(6)(i), granting relief for PRR4 and PRR 10 is authorized by law and will not endanger life or property or the common defense and security, and is otherwise in the public interest, giving due consideration to the burden upon the licensee that could result if the ASME OM Code requirements were im posed on the facility. The NRC staff grants relief for the remainder of the BVPS-2 third 10 year 1ST program interval, which began on November 18, 2007 and ends on November 17, 2017.
All other ASME OM Code requirements for which relief was not specifically requested and approved in the subject request for relief remain applicable.
Principal Contributor: R. Wolfgang Date: June 30,2011
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P. Harden -2 If you have any questions, please contact the Beaver Valley Project Manager, Nadiyah Morgan, at (301) 415-1016.
Sincerely, Ira!
Nancy L. Salgado, Chief Plant Licensing Branch 1-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-412
Enclosure:
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- see memo daet d AIpn'1 4, 2011 OFFICE LPL 1-1/PM LPL 1-1/LA DCI/CPTB/BC LPL 1-1/BC NAME NMorgan SUttle AMcMurtray* NSalgado DATE 6/29/11 6/29/11 4/4/2011 6/30/11 OFFICIAL RECORD COpy