ML20198K855

SER Granting Relief Request PRR-5 for Third 10-year Inservice Testing for Beaver Valley Power Station,Unit 1

ML20198K855
Person / Time
Site:	Beaver Valley
Issue date:	12/21/1998
From:	NRC (Affiliation Not Assigned)
To:
Shared Package
ML20198K830	List: ML20198K825 ML20198K855
References
GL-89-04, GL-89-4, NUDOCS 9812310175
Download: ML20198K855 (6)

Text

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O ter p- 4 UNITED STATES 4

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't NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001

. . . . . ,o SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO THE INSERVICE TESTING PROGRAM DUQUESNE L CHT COMPANY OHIO EDISON COMPANY PENNSYLVANLg POWER COMPANY BEAVER VALLEY POVJR STATION. UNIT NO.1 DOCKET NO. 50-334

1.0 INTRODUCTION

The Code of Federal Regulations,10 CFR 50.55a, requires that inservice testing (IST) of certain American Society of Mechanical Engineers (ASME) Code Class 1,2, and 3 pumps and valves be performed in accordance with Section XI of the ASME BoilerandPressure VesselCode (the Code) l and applicable addenda, except where attematives have been authorized, or relief has been requested by the licensee and granted by the Commission, pursuant to Sections (a)(3)(i), (a)(3)(ii),

or (f)(6)(i) of 10 CFR 50.55a. In proposing attematives or requesting relief, the licensee must 3

demonstrate that: (1) the proposed attematives 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 Director of the Office of Nuclear Reactor Regulation to approve altematives and to grant relief from ASME Code requirements upon making the necessary findings. Guidance related to the development and implementation of inservice testing (IST) programs is given in Generic Letter (GL) 89-04, " Guidance on Developing Acceptable inservice Testing Programs," issued April 3,1989, and its Supplement 1 issued April 4,1995. Additional guidance can be found in NUREG-1482,

" Guidelines for Inservice Testing at Nuclear Power Plants," NUREG/CR-6396," Examples, Clarifications, and Guidance on Preparing Requests for Relief from Pump and Valve inservice i

Testing Requirements," and " Summary of Public Workshops Held in NRC Regions on Inspection Procedure 73756,' Inservice Testing of Pumps and Valves,' and Answers to Panel Questions on inservice Testing issues."

j The 1989 Edition of the ASME Code is the lates' mn incorporated by reference in paragraph (b) of Section 50.55a. Subsection lWP or the 1989 Edition, which gives the requirements  ;

for IST of pumps, references Part 6 of the American National Standards institute /ASME Operations  !

and Maintenance Standards (OM-6) as the rules for IST of pumps. OM-6 replaces specific requirements in previous ed:tions of Section XI, Subsection lWP of the ASME Code.

2.0 BACKGROUND

By letter dated June 11,1998, Duquesne Light Company (DLC), the licensee, submitted a new pump relief request PRR-5 for the third 10-year interval for the Beaver Valley Power Station, Unit No.1 (BVPS-1) IST Program. PRR-5 requested relief to use expanded acceptance ranges for flow and discharge pressure for the emergency diesel generator (EDG) fuel oil transfer pumps at BVPS-1.

The NRC staff issued a request for additionalinformation (RAI) related to pump relief request PRR-5 on August 11,1998. DLC responded to the RAl in a letter dated October 15,1998. DLC's response concluded that "the fuel oil transfer pumps should remain in the BVPS-1 IST Program and continue to be tested in accordance with OM-6 and the approved relief requests. Proposed pump relief request PRR-5 is still considered necessary due to the design and application of the pumps.'

3gO O 34 ENCLOSURE p PDR

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The BVPS-1 IST program for the third 10-year interval began on September 20,1997, and is scheduled to expire on September 20,2007. The BVPS-1 IST program was developed to the 1989 Edition of the ASME Boiler and Pressure Vessel Code,Section XI. The 1989 Edition of the Code specifies that the rules for the inservice testing of pumps and valves are stated in the ASME/ ANSI Operations and Maintenance (OM) Standards, Part 6, " Inservice Testing of Pumps in Light-Water Reactor Power Plants," Part 10, " Inservice Testing of Valves in Light-Water Reactor Power Plants," and OMa-1988 Addenda to the OM 1987 Edition. (Reference DLC third 10-year IST program submittal for BVPS-1 dated April 30,1997; NRC SE dated September 4, 1997; and Revision 1 to the third 10-year IST program for BVPS-1 dated June 2,1998.)

3.0 EDG FUEL OIL TRANSFER PUMP RELIEF REQUEST PRR-5 PRR 5 pertains to the four EDG fuel oil transfer pumps for BVPS-1 (1EE-P 1 A,1EE-P-1B,1EE-P-1C, and 1EE-P-1D). These ASME Code Class 3 screw-type positive displacement pumps transfer fuel oil from the underground EDG fuel oil storage tank to the auxiliary fuel oil day tank in order to provide continuous operation of the diesel at rated load for up to 7 days during an emergency. (The auxiliary fuel oil day tank and engine mounted tank together contain approximately 900 gallons of fuel oil which is only sufficient to supply EDG operation for approximately 4-5 hours at rated load.)

DLC requested relief from Section 5.2(d) of OM-6 for the four EDG fuel oil transfer pumps. This section of the ASME Code requires that " Pressure, flow rate, and vibration (displacement or velocity) shall be determined and compared with corresponding reference values. All deviations from the reference values shall be compared with the limits given in Table 3 and corrective action taken as specified in para. 6.1."

3.1 DLC's Basis for Reauest DLC provided the following basis for the relief request:

In accordance with 10CFR50.55a (f)(5)(iii), relief is requested on the basis that compliance with the code requirement is impractical for BVPS-1.

The limits given in Table 3 for positive displacement pumps for discharge pressure are 0.93 to 1.10P, for the Acceptable Range and 0.90 to <0.93P, for the Alert Range Low, and for flow 0.95 to 1.10Q, for the Acceptable Range and 0.93 to <0.95Q, for the Alert Range Low. These limits are too restrictive for the Fuel Oil Transfer Pumps at BVPS-1. The baseline discharge pressures for these four pumps range between 7 psig and 11 psig. Applying the OM-6 limits for these values, the average allowable degradation from the reference value is only 0.8 psig. The discharge pressure indicators have graduations every 0.2 psig, however, a review of the previous data for discharge pressure since 1985 reveals that the discharge pressure has historically varied as much as 1 psig from one test to the next and between 1-3 psig over the course of a year. In addition, the allowable inaccuracy of the discharge p. essure gauges would allow variations of l

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0.48 psig, equal to more than half of the Acceptable Ranges. The baseline flows for these four pumps range from 9 to 12 gpm. The average allowable degradation for flow is therefore only 0.7 gpm. The flow values also vary from test to test and between 1-3 gpm over the course of the year.

The OM-6 limits are, therefore, too restrictive. Normal historic variation in discharge pressure and flow would require the pumps to enter the Alert or Required Action Ranges. Trends would not be observed because the pumps would have to be declared inoperable before enough data could be obtained to determine if the data obtained is a true indication of a degrading condition or data scatter, in addition, the ASME trending would also pick-up variations caused by fouling of the suction strainer or discharge filter or by chattering of the relief valve.

An allowable variation larger than 0.8 psig or 0.7 gpm, therefore, is needed to trend pump performance.

NUREG 1482, Paragraph 5.6 " Operability Limits of Pumps," states that it expanded renges are needed, relief must be obtained. "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."

Therefore, BVPS-1 requests relief to use expanded ranges for discharge pressure and flow for the Fuel Oil Transfer Pumps. The ranges proposed for discharge pressure would be 0.80 to 1.20P, for the acceptable range and 0.70 to <0.80P, for the Alert Range. The function of these pumps is to be able to deliver fuel to the day tank to supply the Diesel Generator under fullload. The amount of fuel that is required to be delivered is 3.6 gpm, significantly lower than the reference values for all of the pumps, in addition, due to the nature of positive displacement pumps, flow should be the more consistent parameter. Therefore, the proposed range for flow is 0.90 to 1.150, for the Acceptable Range and 0.80 to <0.900,, for the Alert Range. The proposed range for the flow value is more restrictive because the flow rate is the more critical parameter for the system. The high flow limit is based on approximately half of the allowable variation expected in pumps with this rated flow rate, from the Hydraulic Institute Test Standard for Rotary Pumps,14th edition.

These ranges would only result in an average allowed variation of-2.5 psig and

+1.7 psig for pressure and -2.1 gpm and +1.5 gpm for flow. In addition, during discussions with Ingersoll-Dresser Pumps, the pump manufacturer, when questioned about a limiting value for pump performance, the pump manufacturer has stated that as the pump wears and the clearances open, the performance will gradually change. No limiting value for either flow or discharge pressure was provided and sudden performance degradation is not expected. The proposed expanded ranges will allow degrading conditions to be identified and provide assurance that the Fuel Oil Transfer Pumps will be capable of fulfilling their safety function.

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2 3.2 Proposed Altemate Testina The licensee proposed the following:

. i Test per 10ST-36.1 and 2, " Diesel Generator Monthly Tests" using expanded  ;

ranges for flow and discharge pressure. '

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3.3 Evaluation The NRC staff issued a request for additional information (RAl) related to pump relief request i PRR-5 on August 11,1998, that suggested that the BVPS-1 fuel oil transfer pumps need not be  !

included within the scope of the licensee's IST program. DLC's October 15,1998, response stated that " these pumps are considered class 3 components that are supplied with emergency  ;

power, that perform a function in shutting down a reactor to cold shutdown and mitigate the j consequences of an accident, and in accordance with 10 CFR 50.55a, should remain in the BV-1 -

lST Program." In addition, the licensee stated that "in order to ensure these pumps are capable of performing their safety function, they should continue to be tested as separate components,  !

not as subassembly components of the Diesel Generator."

DLC requested relief from the Code specified acceptance criteria for pressure and flow rate on the basis that conformance with these requirements is impractical for BVPS-1. The licensee proposed to test the D/G fuel oil transfer pumps (i.e., per 10ST-36.1 and 10ST-36.2, " Diesel

, Generator Monthly Tests") using expanded ranges for flow and discharge pressure as summarized in the following table.

[('Qyliggy] Acceptable Range Alert Range Required Action

, .u e J d V: 1'%

Range OM-6, Table 3b 0.93 to 1.10 P, 0.90 to <0.93 P, <0.90 P, >1.10 P ,

0.95 to 1.10 Q, 0.93 to <0.95 Q, <0.93 Q , > 1.10 Q ,

Proposed in PRR-05 0.80 to 1.20 P, 0.70 to <0.80 P, <0.70 P, >1.20 P, for the four Fuel Oil 0.90 to 1.15 Q, 0.80 to <0.90 Q, <0.80 Q , >1.15 Q ,

Transfer Pumps DLC stated that the discharge pressure range for these pumps is 7 to 11 psig and that discharge pressure varies as much as 1 psig from one test to the next and as much as 1-3 psig over the course of a year. Flow rate for these pumps range between 9 gpm and 12 gpm and varies as much as 1-3 gpm over the course of a year. DLC suggested that in situations where pump discharge pressure and flow rate vary significantly (e.g., approximately 10 to 40% of the reference pressure and flow rate), as they apparently do with the BVPS-1 fuel oil transfer pumps, it is impractical to meet the restrictive hydraulic acceptance criteria as specified by the Code.

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.S-l During the second ten-year interval, expanded ranges were used for these pumps, as permitted by Section IWP-3210 of the 1983 edition of the ASME Section XI Code which stated:

The allowable ranges of inservice test quantities in relation to the reference values are tabulated in Table IWP-3100-2. If these ranges cannot be met, the Owner shall )

I specify in the record of tests (IWP-6000) the reduced range limits to allow the pump  !

to fulfill its function, and those limits shall be used in lieu of the ranges given in Table IWP-3100-2.

i For this third ten-year interval (which began on 9/20/97), the 1989 edition of the Code is used, which references OM-6. OM-6 does not contain a paragraph similar to IWP-3210 which would allow the use of expanded ranges. Section 5.6,' Operability Limits for Pumps," of NUREG-1482 states that I the OM-6 Working Group could not endorse the IWP philosophy of letting the owner specify any acceptance criteria deemed appropriate when the limits of the applicable table could not be met.

' Because OM-6 is incorporated by reference in Paragraph (b) of 10 CFR 50.55a, licensees that use OM-6 must obtain relief if expanded ranges are needed. l The licensee stated that without expanded acceptance ranges, normal historic variation in discharge pressure and flow rate would require the pumps to enter the alert or required action ranges. Trends would not be observed because tha pumps would have to be declared inoperable before enough data could be obtained to determine if the data obtained is a true indication of a degrading condition or data scatter. DLC has investigated possible causes for the variations in pump discharge pressure and flow rate (e.g., fouling of the suction s' vainer or discharge filter or possible chattering of the downstream relief valve) and has been unable to either correlate the variation to an adverse pump (or system) condition or to limit the magnitude of the variation such that the OM-6 acceptance criteria could reasonably be used. During a telephone conference callwith DLC on November 12,1998, DLC representatives stated that pump discharge pressure and flow rate variations could not be reduced without expending significant additional time and resources (e.g., on pump replacement and/or system redesign). Based on this information, the staff concludes that compliance with the Code is impractical because of design limitations. Imposition of the Code requirements would require significant system redesign and modification.

1 Ingersoll-Dresser Pumps, the fuel oil transfer pump manufacturer, stated that as the pump wears and the clearances open, the pump's performance will gradually change. No sudden pump performance degradation is expected.

i While quarterly testing of the fuel oil transfer pumps is required to satisfy inservice test l

requirements, DLC representatives indicated that these pumps will be tested monthly in '

conjunction with the EDG technical specifications surveillance requirement. While some of the j

monthly tests may not meet all of the IST requirements, they will provide added confidence in  ;

the operational readir,ess of these pumps. During a telephone conference call with DLC ,

representatives on November 12,1998, DLC representatives stated that it would take corrective l actions if any IST parameters on a fuel oil transfer pump falls outside the acceptance criteria I

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1 during any of the monthly tests. The NRC staff considered imposing monthly inservice testing of the 1 fuel oil transfer pumps on DLC (with the expanded acceptance criteria for discharge pressure and l

flow rate) but decided not to reauire the monthly tasting because monthly EDG testing may not consume sufficient fuel oil to support inservice testing of both associated fuel oil transfer pumps (i.e., I without having to possibly drain fuel oil from the auxiliary day tank to a 55 gallon drum).

DLC's proposed expanded ranges for discharge pressure and flow are consistent with the licensing l

basis assumptions in the plant's safety analysis. The reference flow rate for gagh pump is '

significantly higher than the 3.6 gpm required, even at the lower required action flow rate proposed i by DLC. These proposed ranges will allow pump degradation to be identified in a timely manner.

On this basis, the DLC's proposal to use altamate, less-restrictive acceptance criteria for fuel oil l

transfer pump discharge pressure and flow rate is acceptable to the NRC staff. Testing as proposed  ;

by DLC will provide reasonable assurance that the fuel oil transfer pumps will be capable of fulfilling l their safety function.

3.4 Conclusion Relief is granted and the attemative imposed pursuant to 10 CFR 50.55a(f)(6)(i) based on the impracticality of testing the fuel oil transfer pumps in accordance with the Code-specified acceptance criteria. The relief granted is authorized by law and will not endanger the common defense and security and is otherwise in the public interest, giving due consideration to the burden upon the licensee if the Code requirement were imposed on the facility.

Principal Contributor: D. Fischer Date: December 21, 1998