ML20202B857
| ML20202B857 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 11/18/1997 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20202B849 | List: |
| References | |
| GL-89-04, GL-89-4, NUDOCS 9712030200 | |
| Download: ML20202B857 (19) | |
Text
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,, **:u y- lt UNITED STATES 3 o NUCLEAR REGULATORY COMMISSION
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, WASHINGTON, D.C. 3066Ho01 s.,*see*)
SAFETY EVALUAi'ON BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED T0 it? E ND 10-YEAR INSERVICE TESTING PROGRAM DUOVESNE LIGHT COMPANY BEAVER VALLEY POWER STATION. UNIT NO. 2 DOCKET NO.30-412
1.0 INTRODUCTION
The Code of federal Regulatfons,10 CFR 50.55a, requires that inservice testing (IST) of certain American Society of Mechanical Engineers Class 1, 2, and 3 pumps and valves be performed in accordanceSection with(ASME)
XI Code of the ASME Boller and Pressure Vessel Code (the Code) and applicable addenda, except where alternatives have been authorized or relief has been requested by the licensee and granted by the Commission pursuant to Sections (a)(3)(1),
(a)(3)(ii), or (f)(6)(1) of 10 CFR 50.55a. In pro)osing alternatives or requesting relief, the licensee must demonstrate t1at: (1) the proposed alternatives provide an acceptable level of quality and safety; (2) compliance would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety; or (3) conformance is impractical for its facility. Section 50.55a authorizes the Commission to approve alternatives and to grant relief from ASME Code requirements upon making the necessary findings. Guidance related to the development and implementation of IST programs is given in Generic Letter (G!.) 89-04, " Guidance on Developing Acceptable Inservice Testing Programs," issued April 3,1989, and its Supplement 1 issued April 4, 1995. Also see NUREG-1482, " Guidelines for Inservice Testing at Nuclear Power Plants," and NUREG/CR-6396, " Examples, Clarifications, and Guidance on Preparing Requests for Relief from Pump and Valve Inservice Testing Requirements."
l The 1989 Edition of the ASME Code is the latest edition incorporated by reference in Paragraph (b) of Section 50.55a. Subsection IWV of the 1989 Edition, which gives the requirements for IST of valves, references Part 10 of
, the American National Standards Institute /ASME Operatfons and #afntenance l Standants (OM-10) as the rules for IST of valves. OH-10 replaces specific requirements in previous editions of Section XI, Subsection IWV, of the ASME Code. Subsection IWP of the 1989 Edition, which gives the requirements for IST of pumps, references Part 6 of the American National Standards Institute /ASME Operatfons and #aintenance Standards (OM-6) as the rules for IST of pumps. OH-6 replaces specific requiren,ents in previous editions of Section XI, Subsection IWP, of the ASME Code.
Enclosure 9712030200 DR 971118 p ADOCK 05000412 PDR _
l By letter dated May 30, 1997, Duquesne Light Company (DLC), the licensee for Beaver Valley Power Station, Unit No. 2 (DVPS-2), submitted the second 10-year interval IST Program for Pumps and Valves. Included in this suosittal were eight relief requests, Pump Relief Requests 1-6 and Valve Relief Requests 1-2.
The NRC staff's findings with respect to authorizing alternatives and granting '
or not granting the relief requested as part of the licensee's IST program are contained in this safety evaluation (SE).
2.0 EQEE The BVPS-2 IST Program was developed to the 1989 Edition of ASME Section XI for the second 10-year interval that will begin on November 18, 1997. The IST program and deferred test justifications were developed to coniply with the provisto.is of 10 CFR 50.55a and are based on OM-6 and OH-10. Additionally, GL 89-04 and its Supplement 1 (NUREG-1482) were followed in the program development. The program includes only those sumps that are provided with an emergency power source. The licentes states 11at pumps and valves included in the program are ASME Code Class 1, 2, and 3 requird to perform a specific function in shutting down a reactor to the cold shutdown condition, in maintaining the cold shutdown condition, or in mitigating the consequences of an accident.
2.1 Anomalies The following anomalies were noted during the course of the IST program scope review:
The scope of the IST Program for valves described on page 84 of 279 of Enclosure 2 to DLC's May 30, 1997, submittal appears to be incomplete.
The statement, " pressure relief devices covered are those for protecting systems or portions of systems which )erform a required function in shutting down a reactor to the cold stutdown condition, in maintaining the cold shutdown condition, or in mitigating the consequences of an accident," should be included in the IST program scope as called for in Section 1.1 of OH-10.
Relief valves RV-101 and -102 apaear to be Code Class 2 and to have a safety function for protecting ti1e Fuel Pool Cooling & Purification System. These valves should be included in the IST program, as necessary, in accordance with Section 1.1 of OH-10.
DLC should review these items and make changes to their IST program, testing procedures, or other plant documentation as necessary. The scope of the IST program, cold shutdown justifications, refueling cutage justifications, and IST program commitments are subject to NRC inspection.
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3.0 PUMP RELIEF REQUEST 1 {
f Relief is requested from OM-6, Paragraph 6, with regard to doubliss the frequency of testing for pumps when deviations fall within the alert range for ,
vibration measurements. This relief request pertains to all pumps in the IST t program. 1 3.1 Licensee's Basis for Reauant The licensee provided the following basis for the relief request:
The ASME OMc Code-1994, Subsection IST8, Paragraph 4.6, "New Reference j Values," states in cases where a puse i test parameters are within the ;
alert or required action ranges and tw pump's continued use at the !
changed values is supported by an analysis, a new set of reference values may be established. Pargraph 4.G goes on to say that this :
analysis shall include verification of the pump's operational readiness.
The analysis shall also include both a pump levei and system level evaluation of operational readiness, the cause of the change in pump performance, and an evaluation of all trends indicated by available data. The results of this analysis shall be documented in the record of :
tests.
Spectral analysis may be used to determine the mechanical condition of a ,
pump. The reason for testing a pump on double frequency is to obtain additional information so that the condition of the pump may be determined. Spectral data can provide information to determine if misalignment, unbalance, resonance, looseness or a bearing problem is present. Through a review of the spectral data over a period of time, any change in condition of the pump may also be determined.
3.2 Pronosed Alternate Testina ,
The licensee proposed the following:
BVPS-2 proposes to implement ASME OMc Code-1994, Subsection ISTB, Paragraph 4.6 for vibration measurements for all the pumps in the IST Program. Spectral vibration data is currently being obtained for each vibration measurement on all of the pumps. Each time a pump snters the alert range for vibration, an analysis _of the spectral vibration data *
-will be performed to determine the cause of the higher vibrations. If the analysis supports continued operation, the pump will be removed from double frequency testing and a new set of reference valves may be obtained. However, to avoid stair-stepping to failure, a new set of .
reference values may only be obtained once prior to performing ,
corrective maintenance.- If the cause of the higher vibrations cannot be determined, or if the data shows a continuing trend such that the condition of the pump may continue to degrade until it can no longer ;
fulfill its function, the pump will remain on double frequency testing until the condition is corrected.
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3.3 Evaluation OH-6, Paragraph 6.1, " Acceptance Criteria," specifies actions required to be taken if any of the measured pump parameters fall within the alert or required action ranges. For the alert range, the test frequency is required to be doubled until the cause of the deviation is determined and the condition is corrected. Instead of doubling the test frequency, the licensee proposes, for pump vibration that falls into the alert range, an alternative to perform an analysis that demonstrates that the current mechanical and hydraulic performance levels of the pump do not impair the pump oprabilit/ and that the pump would still perform its safety function. To provide reasonable assurance of a pump's operational readiness, the staff believes this analysis should include a comparison of the current vibration spectrum with the baseline vibration spectrum, an evaluation of the trend of available overall vibration amplite 9s and spectra, and the determination of the need for corrective action. At appears that the licensee has included these elements in its proposed alternative described in Section 3.2, above. Also, OH-6, Paragraph 4.5, allows the licensee to establish new reference values after such an analysis is performed.
The 1994 Edition of the ASME OM Code, Subsection ISTB 4.6, "New Reference Values," which is not currently referenced in 10 CFR 50.55a, allows that "[i]n cases where the pump's test parameters a n either within the alert or the required action ranges of ISTB 5.2.1.1. Table ISTB 5.2.1-2 Table ISTB 5.2.2-1, or Table ISTB 5.2.3-1, and the pump's continued use at the changed values is supported by an analysis, a new set of reference value may be established."
This paragraph also states that the analysis shall include both a pump level and a system level verification of pump operational readiness, the cause of the change in pump performance, and an evaluation of all trends indicated by available data. BVPS-2 proposes to implement ASME ONc Code-1994, Subsection ISTB, Paragrcph 4.6 for vibration measurements.
The licensee's proposed alternative does not conflict with the NRC's interpretation of OH-6, Paragraphs 6 and 4.5. The proposal provides an acceptable level of quality and safety since (1) the licensee's proposed analysis provides reasonable assurance of the operational readiness of the pugs and (2) establishing new reference values are allowed by Paragraph 4.5 of OH-6 after an analysis is performed. The analysis is subject to NRC ins >e: tion and must provide reasonable assurance that the degradation recianism will not cause further degradation such that, before the next pump test or before repairs can be performed, the pump would fail.
3.4 Summary The licensee's proposed alternative is authorized pursuant to 10 CFR 50.55a(a)(3)(1) based on the acceptable level of quality and safety t. 3 .till be provided by the alternative.
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> 4.0 PUMP RELIEF RE0 VEST 2 a), which states that the Relief full-scale is requested from range of each OH-6,instrument analog Paragraph shall 4.6.1.2(be nct greater than three times the reference value. Th u request pertains to pumps identified in the attached table. The licensee has proposed to follow an alternative specified in NUREG-1482, Section 5.5.1, which states that the staff will grant relief when the combination of the range and accuracy yields a reading at least equivalent to the reading achieved from instruments that meet the Code requirements (i.e., up to i 6 percent).
4.1 Licensee's Basis,_,~sr Reauest The licensee provided the following basis for the t elief request:
The pumps listed on the attached table use instruments which do not meet '
the requirements of OM-6, Paragraph 4.6.1.2(a), however, the accuracy of the instruments used is more conservative than the requirements of OH-6, Paragraph 4.6.1.1, " Quality," and Table 1, " Acceptable Instrument Accuracy." Per the attached table, the combination of higher range and better accucacy for each instrument yields a reading at least equivalent to the reading achieved from instruments that meet OM-6, Paragraph 4.6.1.1 and Table 1 requirements. Therefore, relief is requested in accardance with NUREG-1482, Section 5.S.1, " Range and Accuracy of Analog Instruments."
4.2 Prooosed Alternate Testina The licensee proposed the following:
Use the [ installed] instruments listed on the attached table at long as the combination of the higher range and better accuracy for each instrument yields a reading at least equivalent to the reading achieved from instruments that meet OH-6 requirements.
4.3 Evaludd.Qn The licensen has proposed to use permanently installed analog pump precsure instruments identified in the attached tabl6 that do not meet the range requirements of the Code. The instrument accuracy and range requirements of OH-6, Paragraph 4.6, are to ensure that test measurements are sufficiently sensitive to changes in pump condition to allow detection of degradation.
OH-6, Paragraph 4.6, states that (1) accuracy for instruments used in thu measurement of pressure shall be 12 percent and (2) foll-scale range of analog instruments shall be three times the reference value or less. A range of greater than three times the reference value can be acceptable if the instrumera is proportionately more accurate than required. As indicated in Section 5.5.1 of NUREG-1482, an alternative can be approved if the combination of range and accuracy yields a reading that meets i 6 percent of reference value.
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i The licensee has proposed to follow the guidelines in NUREG-1482, Section 5.5.1, which states that the staff will grant relief when the combination of the range and accuracy yields a reading at least equivalent to the reading achieved from instruments that meet the Code requirements. For each of the instruments identified in the table, the combination of rage and accuracy yields a reading that meets i 6 percent of reference value. The licensee's proposed alterative therefore provides an acceptable level of quality and safety for testing. b 4.4 Sumary The proposed alternative is authorized pursuant to 10 CFR 50.55a(a)(3)(1) based on a determination that the proposal provides an acceptable level of quality and safety.
5.0 EUfLD_ BELIEF RE0 VEST 3 Relief is requested from the requirement of OH-6, Paragraph 5.2(b), which states as follows:
The resistance of the system shall be varied until the flow rate equals the reference v.lue. The pressure shall then be determined and compared to its reference value. Alternatively, the flow rate can be varied until the pressure equals the reference value and the flow rate shall be determined and compared to the reference flow rate value.
This relief request pertains to the Primary Component Cooling Water Pumps 2CCP*P21A, B, and C.
5.1 Licensee's Basis for Reauest The licensee provided the following aasis for the relief request:
[These pumps function t]o circulate cooling water through various reactor plant components during normal operation, and through the Residual Heat Remaval Heat Exchangers following an accident in order to achieve and maintain the plant in a cold shutdown condition.
The amount of Primary Component Cooling Water (CCP) System flew is dependent on the Service Water System and on seasonal Ohio River water temperatures due to the design of the CCP temperature control system.
During Primary Component Cooling Pump testing, additional flow is obtained by placing the Residual Heat Removal (RHR) System Heat Exchangers into service. The overall amount of flow may vary by several hundred gallons per rinute between cool winter months and warm summer months.
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In order to increase flow to a reference value during cold winter months, the manual valves at the discharge of the RHR Heat Excha.ngers would require throttling in the open direction. These valves hre located in the reactor containment building which is maintained subatmospheric as required by technical specifications. The subatmospheric condition present,s a hazardous working environment for station personnel (i.e., requires self-contained breathing apparatus and entry via an airlock into an atmosphere of approximately 9 psia) and is considered inaccessible for surveillance testing. Surveillance testing that nquires reactor containment entry is performed at cold shutdown and refueling.
In order to throttle flow to a reference value during warm summer months, a manual valve at the discharge of the pumps heeds to be used since the RHR Heat Exchanger throttle valves are located inside
- containment. Operating experience has shown that any throttling of the pump discharge valves results in a large reduction in cooling water flow to the Reactor Coolant Pump thermal barrier heal exchangers, bearing lube oil coolers and motor stator air coolers resulting in low flow alarms, this could result in heatup of the Reactor Coolant Pumps to near required manual pump trip setpoints which could ultimately result in a plant trip. In addition, the added thermal cycling of these coolers for pump testing could prematurely degrade these heat exchangces.
03 6 Paragraph 4.5, "To Establish an Additional Set of Reference Values," provides for multiple sets of reference values. A pump curve is merely a graphical representation of the fixed response of the pump to an infinite number of flow conditions which are based on some finite number of referena values verified by measurement. Relief is, therefore, requested to use a pump curve, which should provide an equivalent level of quality and safety in trending pump ,ncrformance and degradation. Flow will be permitted to vary as system conditions require. Delta-P will be calculated and converted to a developed head for which OH-6 ranges will be applied.
5.2 Proposed Alternate Testina The licensee proposed the following:
A pump curve (developed per the guidelines in NUREG-1482, Section 5.2, "Use of Variable Reference Values for Flow Rate and Differential Pressure During Pump Testing") will be used to compare flowrate with developed pump head at the flow conditions dictated by seasonal temperatures each quarter per 20ST-13.1, 20ST-15.2, and 20ST-15.3 (Component Cooling Water Pump Tests). Since normal flow varies based on Component Cooling Water System requirements due to Service Water System and seasonal Ohio River water temperatures, 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.
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5.3 Evaluation OH-6 requires that pump flow rate and differential pressure be evaluated against reference values to monitor pump condition and to allow detection of hydraulic degradation. The Primary Component Cooling Water Pumps 2CCP*P21A, B, and C cperate under varying flow and differential pressure conditions, depending on the load requirements. It would not be practical to establish a fixed reference point for testing the component cooling pumps because of system constraints that could result in plant trip and damage to equipment.
When it is impractical to test a pump at a reference value of flow and differential preasure, testing in the "as-found" condition and comparing values to an established refetence curve may be an acceptable alternative.
Pump curves represent a set of infinite reference points of flow rate and differential pressure. Establishing a reference curve for the pump when it is known to be operating acceptably, and basing the acceptance criteria on this curve, can permit evaluation of pump conditien and detection of degradation.
The licenset proposes to follow the NRC guidelines specified in NUEG-1482, Sect. ton 5.2, hir the use of pump curve. The proposal in Pump Relief Request 3, therafore, provides a reasonable alternative to the Code requitecents.
5.4 Sunry Based on the determination that compliance with the Code requirements is impractical, and considering the burden on the licensee if the Code requirements are imposed, relief is granted from the Code requirements pursuant to 10 CFR 50.55a(f)(6)(1).
6.0 PUMP RELIEF RE0 VEST 4 Relief is requested from the requirement of OH-6, Paragraph 5.2(b), which states as follows:
The resistance of the system shall be varied until the flow rate equals the reference value. The pressure shall then be determined and compared to its reference value. Alternatively, the flow rate can be varied until the pressure equals the reference value and the flow rate shall be determined and compared to the reference flow rate value.
This relief request pertains to the Service Water Pumps 25WS*P21A, B, and C.
6.1 Licensee's Basis for Reauest The licensee provided the following basis for the relief request:
[These pumps function t]o provide cooling water to various reactor plant components under normal and emergency conditions, and through the Recirculation Spray Heat Exchangers following a DBA [ design basis accident].
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Operating experience has shoun that plant conditions due to heat loads requiring cooling by the Service Water System may preclude retu ning the Service Water Pumps to the exact flowrate or differential prestro during pump surveillance testing. The Service Water System is d?nedent on seasonal Ohio River water temperatures and flow may vary from approximately 6,000 gpm in the cool winter months to approximately 14,000 gpm in the warm sumner months.
In order to increase flow to a reference value during 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 'lollowing cleaning tn 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 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 and/or removal of heat exchangers from ser ice for pump testing could prematurely degrade the heat exchangers.
The thermal transients created by increasing or throttling Service Water System flow to the turbine plant cooling loads raises operational concerns of stability problems. Changes in oil temperature from the turbine generator lube oil system create vibration problems. Changes in the Hydrogen gas cooler temperatures could imply problems or mask real problems with the generater. Chiller unit heat exchanger flow disturbances often result in a trip of the chiller unit causing reactor containment temperature risks of exceeding the technical specification limit.
OH-6, Paragraph 4.5, "To Establish an Additional Set of Reference Values," provides for multiple sets of reference values. A pump curve is merely a graphical representation of the fixed response of the pump to an infinite number of flow conditions which are based on some finite number of reference values verified by measurement. Relief is, therefore, requested to use a pump curve, which should provide an equivalent level of quality and safety in trending pump performance and degradation. Flow will be permitted to vary as system conditions require. Delta-P will be calculated and converted to a developed head for which OH-6 ranges will be applied.
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- 10 6.2 Pronosed Alternate Testina The licensee proposed the following:
A pump curve (developed per the guidelines in NUREG-1482, Section 5.2, "Use of Variable Reference Values for Flow Rate and Differential Pressure During Pump Testing") will be used to compare flowrate with developed pump head at the flow conditions dictated by Service Water System loads each quarter per 20ST-30.2, 20ST-30.3, and 20ST-30.6 (Service Water Pump Tests). Since normal flow varies based on Service Water System requirements due to seasonal Ohio River water temperatures, 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.
6.3 Evaluation OM-6 requires that pump flow rate and differential pressure be evaluated against reference values to monitor pump condition and to allow detection of hydraulic degradation. The Service Water Pumps 2SWS*P21A, B, and C operats under varying flow and differential pressure conditions, depending on the load requirements. It would not be practical to establish a fixed reference point for testing the component cooling pumps because of system constraints that could result in plant trip and damage to equipment.
When it is impractical to test a pump at a reft rence value of flow and differential pressure, testing in the "as-found" condition and comparing values to an established reference curve may be an acceptable alternative.
Pump curves represent a set of infinite reference points of flow rate and differential pressure. Es: >11shing a reference curve for the pump when it is known to be operating acceptably, and basing the acceptance criteria on this curve, can permit evaluation of pump condition and detection of degradation.
The licensee proposes to follow the NRC guidelines specified in NUREG-1482, Section 5.2, for the use of pump curve. The proposal in Pump Relief Request 4, therefore, provides a reasonable alternative to the Code requirements.
6.4 Summarv .
Based on the determination that compliance with the Code requirements is impractical, and considering the burden on the licensee if the Code requirements are imposed, relief is granted from the Code requirements pursuant to 10 CFR 50.55a(f)(6)(i).
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- 11 7.0 12 1 RELIEF RE0 VEST 5 Relief is requested from OH-6, Paragraph 4.6.4(b), which states that, on vertical line shaft pumps, vibration measurements shall be taken on the upper motor bearing housing in three orthogonal directions, one of which is the axia1 direction. This request pertains to Service Water Pumps 2SWS*P21A, B, and C.
7.1 Licensee's Basis for Reauest The licensee provided the following basis for the relief request:
[These pumps function t]o provide cooling water to various reactor plant components uder normal and emergency conditions, and through the Recirculation Spray Heat Exchangers following a DBA.
Access to the upper motor beartrg housing on the vertical line shaft Service Water Pumps for the pu pose of measuring vibrations in the axial direction, cannot be obtained due to the presence of a permanently installed non-rigid metal top hat covering the entire top of the motor housing. However, vibration measurements in the axial direction are accessible at the lower motor bearing housing of each pump which will provide additional information for trending of pump / motor performance.
In addition, the vibration measurements in the orthogonal directions typically provide a better predictor of vibration problems for vertical line shaft pumps.
7.2 Proposed Alternate Testina The licensee proposed the following:
Heasure vibrations on the upper motor bearing housing in two orthogonal directions (excluding the axial direction), and measure vibrations on the lower motor bearing housing in ti..ee orthogonal directions (including the axial direction) each quarter per 20ST-30.2, 20ST-30.3 and 20ST-30.6 (Service Water Pump Tests).
7.3 Evaluation The Codo requires that vibration measurements for vertical line shaft pumps be taken on the upper motor bearing housing in three orthogonal directions, one of which is axial. The licensee has requested relief for the axial vibration measurements because the upper motor bearing housing in the axial direction for the pumps in question is impeded by a permanently installed non-rigid top hat.
It would be a hardship without a compensating increase in safety for the licensee to modify these pump to measure axial vibration from the upper motor bearing housing given that the licensee will be taking vibration measurements in (1) three orthogonal directions at the lower motor bearing housing, and (2)
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- , two orthogonal directions, which are non-axial, at the upper motor bearing housing. The licensee's proposed locations for taking vibration measurement should not be subject to dampening effects of non-rigid structural contact that could mask potential degradation. Further, in recognition of inherent deficiencies in the vibration testing for vertical line shaft pumps, hydraulic performance requirements are more stringent for vertical lino shaft pumps than for centrifugal pumps. Therefore, the licensee's proposed alternative locations for tacing vibration measurements would not compromise a reasonable asserance of operational readiness.
7.4 Summary The proposed alternative to the Code vibration measurement requirements is authorized pursuant to 10 CFR 50.55a(a)(3)(ii) based on the determination that compliance with the specified requirements results in a hardship without a compensating increase in the level of quality and safety.
8.0 PUMP REllEF RE0 VEST 6 Relief from the requirements of OH-6, Paragraph 4.6.5, on the measurement of flow using a rate or quantity meter installed in the pump test circuit, is requested for the Emergency Diesel Generator (EDG) Fuel Oil Transfer Pumps 2EGF* P21A, B, C, and D.
8.1 Licensee's Basis for Reauest The licensee provided the following basis for the relief request:
[These pumps function t]o transfer fuel oil from the underground Emergency Diesel Generator Fuel Oil Storage Tank to the Day Tank in order to provide continuous operation of the Diesel at rated load for up to seven days during an emergency.
There is no installed instrumentation provided to measure flow rates for these Emergency Diesel Generator Fuel Oil Transfer Pumps. Hcwever, a level sight glass does exist on the side of the Diesel Generator Fuel 011 Day Tank which can be used to measure a change in level over time as the pumps transfer fuel oil from the underground Storage Tank to the Day Tank. The reading scale for measuring the level change over time, and the calculational method yield an accuracy within i 2% as required by OH-6, Paragraph 4.6.1.1, " Quality," and Table 1, " Acceptable Instrument Accuracy."
8.2 Proposed Alternate Testina The licensee proposed the following:
Flow rate will be calculated by measuring the level change over time in the Diesel Generator Fuel 011 Day Tank and converting this data into Fuel Oil Transfer Pump flow rates at least quarterly per 20ST-36.1 and 20ST-36.2 (Emergency Diesel Generator and Fuel Oil Transfer Pump Tests).
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- 13 8.3 Evaluation OH-6, Paragraph 4.6.5, " Flow Rate Measurement," states the following:
When measuring flow rates, use a rate or a quantity meter installed in the pump test circuit. If a meter does not indicate the flow rate directly, the record shall include the method used to reduce the data.
If the licensee determines that the measurement of tank level over the period of test performance meets the requirements for "a rate or quantity meter installed in the pump test circuit," and the test procedure includes the method used to reduce the data for calculation of flowrate, relief is not required. If these requirements cannot be met, the staff has determined that the use of a tank level to calculate flowrate is an acceptable alternative to the Code, provided the calculated results meet the accuracy requirements of OM-6, ensuring an acceptable level of quality and safety.
8.4 Summary The proposed alternative to the Code requirements is authorized pursuant to 10 CFR 50.55a(a)(3)(1) based on the alternative providing an accepta' ale level of quality and safety. If the licensee determines that the alternative meets the requirements of OH-6, Paragraph 4.6.5, this relief request may be deleted, provided the method of reducing the data obtained from the level instrument (s) is included in the test procedure.
9.0 VALVE RELIEF RE0 VEST 1 Relief is requested from OM-10, Paragraphs 4.3.2.1 and 4.3.2.4(a), for check valves 2 SIS *141,142,145,147,148, and 151 in the Safety Injection System.
Paragt aph 4.3.2.1 requires chock valves to be individually exercised nominally every 3 months, except as provided by Paragraphs 4.3.2.2, 4.3.2.3, 4.3.2.4, and 4.3.2.5. Paragraph 4.3.2.4(a) states that the necessary valve obturator movement shall be demonstrated by exercising the valve and observing that the obturator moves to the open and/or closed position (s) required to fulfill its function.
9.1 Licensee's Basis for Reauest The licensee provided the following basis for the relief request:
These Safety Injection (SI) Accumulator series discharge check valves must open upon a depressurization of the RCS during a loss of coolant accident (LOCA) to provide a flowpath from the SI Accumulators to the reactor coolant system (RCS) cold legs. [2 SIS *141 and 145] must also open to provide a flowpath for the residual heat removal (RHR) system when it is placed into service for cooldown of the plant to cold shutdown conditions.
These check valves are normally closed as )ressure isolation valves (PIVs) during plant operation to isolate t1e lower pressure SI Accumulators from the high pressure RCS. Their safety position is open for passive low pressure injection of the SI Accumulators into the RCS cold legs during a LOCA. An additional safety position for [2 SIS *141 and 145] is open to support RHR system operation during cooldown of the plant to cold shutdown conditions. Full- or part-stroke exercising in the open direction cannot be performed during plant operation because the RCS is at a higher pressure than the SI Accumulators. During cold shutdowns, [2 SIS *141 and 145) are capable of being part-stroke exercised in the open direction during RHR system operation. However, full-stroke oxercising of all six check valves in the open direction by initiating the maximum required accident condition flowrate in accordance with Generic Letter No. 89-04, Position 1, in addition to part-stroke exercising the remaining four check valves in the olen direction, cannot be performed during cold shutdowns because of a lacc of installed instrumentation. A proposed alternate method which me3sures a flow coefficient value (Cv) during a blowdown at reduced accumulator pressure (see next paragraph), also cannot be performed during cold shutdowns because of a lack of installed instrumentation and an uncontrolled test volume change if the SI Accumulator discharge MOV isolation valves are opened at low RCS pressure. In addition, the reduced pressure which is required to perform this alternate test method may not always be obtainable during each cold shutdown. Therefore, stroke testing, if attempted at cold shutdowns, could extend the length of a plant shutdown due to the extensive preparatory work in establishing the proper RCS and SI Accumulator conditions necessary to perform the test, due to delays involved with installation and removal of test equipment inside containment, and for delays while the SI Accumulators are refilled and pressurized. For [2 SIS *141 and 145L, OH-10, Paragraph 4.3.2.2(d) states, "if exercising is not pract' cable during plant operation and full-stroke during cold s!.atdowns is also not practicable, it may be limited to part-stroke during cold shutdown, and full-stroke during refueling outages." For the remaining check valves, OH-10, Paragraph 4.3.2.2(e) states, "If exercising is not practicable during plant operation or during cold shutdowns, it may be limited to full-stroke during refueling outages."
Relief is requested to full-stroke exercise the SI Accumulator series discharge check valves in the open direction during each refueling outage using a method similar to the test used at the Fort Calhoun Nuclear Station (
Reference:
NUREG-1482, Section 4.1.2, " Exercising Check Valves with Flow and Nonintrusive Techniques," Issue 1). The test method will measure a flow coefficient value (Cv) during a blowdown at reduced accumulator pressure. The SER for the Fort Calhoun test method will be followed and the recommendations incorporated.
.. 9.2 Prenosed Alternate Testino The licensee proposed the following:
[2 SIS *141 shutdowns!and 145) will per 20ST-10.1 andbe part-stroke 20ST-10.2 (RHRexercised open during Pump Perforrance Tests). cold The remaining check valves will be full-stroke exercised open during refueling outeges per 2BYT 1.11.3 (SI Accumulator. Discharge Check Valves s Full Stroke Test). As a special test after maintenance, 20ST-ll.15 may be performed to part-stroke exercise applicable check valve (s) in the open direction.
9.3 Evnluation Full-stroke exercising these valves during power operation is not practicable because the RCS is at a higher pressure than the Accumulator. During cold shutdowns, the RCS lacks adequate expansion volume to accommodate the required flow and a low temperature overpressure condition could result. These valves could only be full-stroked exercised quarterly or during cold shutdowns if extensive system modifications were performed, such as installing full-flow test loops. Making such modifications would be burdensome to the licensee.
The licensee proposed to full-stroke open these valves during refueling outages and partial-stroke open valves 2 SIS *141 and 145 during cold shutdowns as part of the RHR system operation. The alternative testing frequencies are consistent with the requirements of OM-10, Paragraph 4.3.2.2, which allows deferral of stroke testing to every refueling outage if testing quarterly or during cold shutdowns is not practicable.
The licensee's method of exercising these valves open, by measuring a flow coefficient value (Cv) during a blowdown at reduced accumulator pressure, had previously been approved for Fort Calhoun with the provision that the recommendations specified in the ORNL report, ORNL/NRC/LTR-93-16, be followed.
This method of exercising these valves is consistent with the OH-10, Paragraph 4.3.2.2 requirements; relief is therefore not required. The licensee states that the Fort Calhoun test method will be followed for BVPS-2 and the recommendation incorporated.
9.4 Summary Based on the determination that the alternative testing is consistent with OH-10, Paragraph 4.3.2.2 requirements, no relief is required. The implementation of IST program commitments is subject to NRC inspection.
10.0 VALVE RELIEF RE0 VEST 2 Relief is requested from OH-10, Paragraph 4.2.1.4(b), which states that the stroke time of all power-operated valves shall be measured to at least the nearest second. This request pertains to diesel generator air start solenoid
7 operated valves 2EGA*SOV202-1, 2EGA*S0V202-2, 2EGA*S0V203-1, and 2EGA*S0V203-
- 2. The licensee proposes to verify the operational readiness of these solenoid valves by confirmation of proper diesel start times during the EDG testing.
10.1 Licensee's Basis for Reauest The licensee provided the following basis for the relief request:
These valves are quick acting and do not have position indication.
Therefore, in accordance with NUREG-1482, Section 4.2.8, " Solenoid-
' Operated Valves," operition of these valves will be monitored by timing the starting time to rated speed of each Emergency Diesel Generator-(EDG). Individual valves will be tested by isolating one bank of air prior to starting the EDG on an alternating frequency. This will ensure each bank is capable of starting-the EDGs in the required time and that the air start solenoids are not degrading. Per NUREG-1482, Section 3.4,
" Skid-Mounted Com>onents and Component Subassemblies," the staff has determined thtt tie testing of the major component is an acceptable means for verifying the operational readiness of the skid-mounted ans' component subassemblies if the licensee documents this approach in the IST Program.
10.2 Proposed Alternate Testina The licensee proposed the following:
- [These valves will be s]troked and indirectly timed on an alternating frequency in conjunction with 20ST-36.1 and 20ST-36.2 (Emergency Diesel Generator Monthly Tests). [The licensee will a]ssign a limiting stroke L time based on the EDG start 1ng requirements for ESF response time (EDG
. ready to accept the lead in $10 seconds).
10.3 Evaluation .
The Code requires that the diesel air start solenoid valves be stroke timed every three months. These valves have a safety function to open ins conjunction with the operation of their associated diesel generators. The air start solenoid valves are small, rapid acting valves that are completely enclosed. They operate from an engine start control signal rather than a control switch and do not have remote position indication or.any external means to determine valve position. Therefore, it is impractical to stroke time test these valves as required by the Code. Failurn or significant degradation of these valves would be evidenced by failure to meet the diesci start time limit specified in the Technical Specifications. It would be an undue burden for the licensee to meet the Code requirements because components associated with EDG would have to be either modified or replaced. The
--licensee proposes to verify quarterly the operational readiness of these
- valves by confirmation of proper diesel start times. This proposed i
alternative is consistent with the NRC guidelines in Section 3.4 of NUREG-1482 and provides a reasonable alternative to the Code requirements. .
.. 10.4 Summary Based on the determination that compliance with the Code requirements is ,
impractical and the licensee's proposal provides a reasonable alternative to the Code requirements, relief as requested is granted pursuant to 10 CFR 50.55a(f)(6)(1).
11.0 CONCLUSION
The proposed alternatives in Pump Relief Requests 1, 2, and 6 are authorized pursuant to 10 CFR 50.55a(a)(3)(1). The proposed alternative in Pump Relief Request 5 is authorized pursuant to 10 CFR 50.55a(a)(3)(ii). Valve Relief Recuest 1 is not required. Valve Relief Request 2 and Pump Relief Requests 3 anc 4 are granted pursuant to 10 CFR 50.V3(f)(6)(1). The staff has determined that approval of relief reques.. pursuant to 10 CFR 50.55a(a)(3)(1), (a)(3)(ii), or (f)(6)(1) is authorized by law and will not endanger life or property, or the common defense and security ano is otherwise i in the public interest. The licensee should respond to the NRC within one year of the date of this SE describing actions taken, actions in progress, or actions to be taken, to address each of the anomalies in Section 2.1 of this SE. The :cu p of the IST program, cold shutdown justifications, refueling outage jur liications, and IST program commitments are subject to NRC inspection.
The staff concludes that the relief requests as evaluated and modified by this SE will provide reasonable assurance of the operational readiness of the pumps and valves to perform their safety-related functions. The staff has determined that granting relief pursuant to 10 CFR 50.55a (f)(6)(1) and authorizing alternatives pursuant to 10 CFR 50.55a (a)(3)(1) or (a)(3)(ii) are authorized by law and will not endanger life or property, or the common defense and security and are otherwise in the public interest. In making this determination, the staff has considered the impracticality of performing the required testing and the burden on the licensee if the requirements were imposed.
Principal Contributor: K. Dempsey Date: Fr ember 18, 1997
t ,
PUMP RELIEF REQUEST 2: IST PUMP INSTRUMENTATION Condition Requiring Relief Basis for RelieFAlternateTest PumpID# Instrument ID#
The range of the gauges is These gauges are the suchon p==c gauges for the Charging Pwnps. They are sized 2CIIS*P21A 2CHS-Pil51A greater than three times the for all modes of pump operabon mcludmg accident condinons (i.e., can take suchon 2CHS*P2iB 2CHS-Pil52A referencerusures during from the Reenculation Spray Pumps) with a range of 0-160 psig. Durmg recirculation 2CHS*P21C 2CIIS-PIl53A quarterly recirculation flow flow testing, the suebon pressures are approx. 25% of the range. Dunng full flow testing and during full flow testing, the suctenr-- w are approx. 10% of the range. Their calibrabon '
testing at refueling accuracy is 0.5%, winch would yield a readmg more accurate than OM-6 sqaw:s.
The range of the gaugesis These gauges are the sucuan rm c gauges for the Borie Acid Transfer Pumps.
2CHS*P22A 2CHS-Pil23A greater than three times the They are sized for all modes of pump operation and Boric Acid Storage Tank levels 2CHS*P22B 2CHS-Pil23B reference pressures during with a range of 0-30 psig. Duing quarterly testing, the suwonrm-s are approx.
quarterly testing. 10-15% of the range. Their calibrabon eu.ui.cy is 0.5%, which .vould yield a readmg more accurate than OM-6 rqammu.
The range of the gauges is These gauges are the suction pressure gauges for the Iow Head Safety Inkchi 2 SIS *P21A 2 SIS-PI938 greater than three times the Pumps. They are sized for recirculation and full flow testing with a range of 0-160 2 SIS *P21B 2 SIS-P1939 reference pressures during psig. During recueulation flow testing, the suchonrmms are approx. 20% of the quarterly recirculation flow range. Durmg full flow testing, the suchon r w s are approx.10% ofthe range testing and during full flow Their calibration accuracy is 0.5%, wiuch would ,ield a readmg more accurate than testing at refueling. OM-6 requirements.
Test Gauges The range of the gauges may be A test gauge is installed on the suchon line of each Recirculation Spray Pump during 2RSS*P21 A greater than three times the testing at refueling A test dam is erected and filled with water to prende NPSH. The 2RSS*P21B (Suchon Pressure) referencerm-s during gauges are sized for varying levels of water in the test dsn with sucuon pressura 2RSS*P2iC festing at refueling. varying typically between 5-30 IWC. The gauges ofvarying ranges and accuracies 2RSS*P21D may be used; however, the combinaten of range and w.cy wouki yield ar m-e reading within 10.3 IWC. Therefore, their better calibrabon with a larger range would a
yield a readmg more accurate than OM-6 rw m..c..:5.
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PUMP RELIEF REQUEST 2: IST PUMP INSTRUMEhTATION Condition Requiring Relief Basis for RelicFAkermateTest TumpID# Instrument ID#
'Ihe range of the gauges is 'Ihese are the suction presan gauges for the Coup Cooling Water Pumps.
2CCP*P21A 2CCP-Pil50A 2CCP-Pil50B greater than three times the They are sized for all modes of pump operation with a range of 040 psig. A pump 2CCP*P21B referenceemed during curve is used during quarterly testmg as approved by Pump Relief Request No. 3.
2CCP'P21C 2CCP-Pil50C quarterly testing. The suction p w m vary between 24-37% of the range. Their calibration w=.cy is 0.5%, which would yield a readmg more accurate than OM4 imm 3 I
2FWE-FIl00A The range of the gauges is These flow meters are located in three lines to the Steam Generators from the 2FWE*P23A 2FWE-F1100B greater than three times the Auxiliary Feedwata (AFW) Pumps 'Ihey are ach sized with a range of 0 400 gpm 2FWE*P23B reference flows during full flow to measure accident flows from the Turbme-Dnven AFW Pump [2FWE*P22J. 'lhey 2FWE-Fil00C testing at cold shutdowns and are also used to mese2re accident flows from the Motor-Drive AFW Pumps refueling. [2FWE*P23A and B], but at a lesser flow rate of approx. 30% of the range. Their calibration accuracy is 1.5%, wluch would yield a readmg more act.arate than OM4 requuements.
'Ihe range of the gaugesis These are the discharge pressure gauges for the E..~ su.cy Du:sel Generator Fuel Oil 2EGF aIA 2EGF-PI201A 2EGF-P1201B greater than three times the Transfe- Pumps. 'Ihey are sized for all modes ofpump operation with a range of 0-30 2EGF'P21B 2EGF-PI201C referencer w-s during psig. Durmg bimocihly testing, discharge r se are between 8.5 and 10.5 psig, 2EGF'P21C 2EGF-P1201D bimonthly testing. slightly below 1/3 of the range. Their calibration accuracy is 1.0%, winch would yield 2EGF'P21D a readmg more accurate than OM4 re c ..aas.
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