ML20128K771

Safety Evaluation Granting Relief from Certain Inservice Testing Program Requirements for Several Pumps & Valves

ML20128K771
Person / Time
Site:	Brunswick
Issue date:	02/11/1993
From:	Office of Nuclear Reactor Regulation
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ML20128K769	List: ML20128K762 ML20128K771
References
NUDOCS 9302190002
Download: ML20128K771 (13)

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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATIQN RELATED TO THE INSERVICE TESTING PROGRAM REllEF RE0 VEST FOR

[A.R0 LINA POWER & LIGHT COMPANY BRUNSWICK STEAM ELECTPlc PLANT. UNITS 1 AND 2 DOCKET NOS. 50-325 AND 50-324

1.0 INTRODUCTION

By letter dated September 15, 1992, Carolina Power & Light Company submitted several Inservice Testing Program relief requests for Brunswick Steam Electric Plant, Units 1 and 2. Pump-related relief requests are PR-06 and PR-07; and VR-32, VR-33, VR-34, VR-35, VR-36, ano VR-37 are valve-related relief requests, all for the Second Ten-year Interval inservice Yesting Program for the Brunswick Plant which began on July 10, 1986, and ends July 9, 1996. The Inservice Testing Program was based on the requirements of Section XI of the American Society of Mechanical Engineers (ASME) Code,1980 Edition through the Winter 1981 Addenda.

Title 10 of the Code of Federal Regulations, Section 50.55a, requires that inservice testing of certain ASME Code Class 1, 2, and 3 pumps and valves be performed in accordance with Section XI of the ASME Boiler and Pressure Vessel Code and applicable addenda, except where specific written relief has been requested by the licensee and granted by the Commission pursuant to Section (f)(6)(i) of 10 CFR 50.55a or an alternative is authorized by the Commission pursuant to Sections (a)(3)(i) or (a)(3)(ii) of 10 CFR 50.55a. In requesting relief or proposing an alternative, the licensee must demonstrate that (1) conformance with certain requirements of the applicable Code Edition and Addenda is impractical for its facility; (2) the proposed alternative (s) provides an acceptable level of quality and safety; or (3) compliance would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety. Section 50.55a(f)(4)(iv) provides that inservice tests 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 the limitations and modifications listed, and subject to Commission approval. NRC guidance contained in Generic letter 89-04, " Guidance on Developing Acceptable Inservice Testing Programs,"

provided alteinatives to the Code requirements determined to be acceptable by the staff and authorized the use of the alternatives in Positions 1, 2, 6, 7, 9, and 10 provided the licensee follow the guidance delineated in the applicable position. When an alternative is proposed which is in accordance on August 6,1992, The Comission amended its regulation 10 CFR Part 50 (57 FR 34666). The final rule separated the requirements for inservice testing from those for inservice inspection by placing the requirements for inservice testing in a separate paragraph - 10 CFR 50.55a(f). Att subsequent references in this safety Evaluation to any portion of 10 CFR 50.55a(f) were previously 10 CFR 50.55a(g) prior to this final rule change.

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with Generic letter 89-04 guidance and is documented in the Inservice Testing Program, no further evaluation is required; however, implementation of the alternative is subject to NRC inspection.

In evaluating the licensee's requests for relief from the requirements of Section XI, the staff considered (1) the acceptability of proposed alternative testing, (2) whether the hardship of compliance is without a compensating increase in safety, and (3) the impracticality of performing the required testing considering the burden if the requirements were imposed. For the relief-granted per Generic Letter (GL) 89-04, pursuant to 10 CFR 50.55a(f)(6)(i), the staff has determined that granting relief is authorized by 18w and will not endanger life or property, or the common defense and security, and is otherwise in the public interest. The granting of relief or -

authorization of proposed alternatives is based upon the fulfillment of any commitments made by the licensee in its basis for each relief request and the proposed alternate testing.

2.0 EVALVATION 2.1 Relief Request PR-06 Relief Request PR-06 requests relief from the vibration testing requirements of IWP-4500. The licensee proposes to do the vibration testing in accordance with American Society of Mechanical Er.gineers/American National Standards Institute (ASME/ ANSI) Operations and Maintenance Standard Part 6 (OM-6),

" Inservice Testing of Fumps in Light-Water Reactor Power Plants," which the staff has approved, ts opposed to doing it in accordance with tne Code as specified in IWP-4500.

2.1.1 Licensee's basis for relief The licensee states: -

The Brunswick Plant has previously committed to implementing OM-6 for vibration monitoring in pump relief request PR-01, approved by the NRC in Safety Evaluation issued January 4, 1990, for the Second Ten Year Inservice Testing Program. ANSI /ASME Operation and Maintenance standard (OM-6) is now incorporated into the 1989 edition of-ASME Code,Section XI. Relief request PR-01 states the alternate testing, in lieu of bearing temperature, to be vibration testing in accordance with the 1987 Edition of ASME/ ANSI OM, " Operation and Maintenance of Nuclear Power Plants," Part 6, " Inservice Testing of Pumps in Light-water Reactor Power Plants." The vibration testing in accordance-with this standard is more stringent and is technically more accurate than that which is required in IWP-4500.

2.1.2 Alternative test'ng Perform vibration testing in accordance with the 1987 Edition of OM-6.

2.l_.3 Evaluation of Relief Request PR-06 The licensee previously committed (i.e., in relief request PR-01) to perform vibration monitoring as specified in the 1987 version of OM-6 in lieu of

., - -_ j bea' ring temperature monitoring. The NRC reviewed relief request PR-01 and

. approved itt in- an NRC Safety Evaluation dated January 4,-1990 (for the Second Ten-Year Inservice Testing _ Program). The licensee states that this vibration

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testing done in accordance with OM-6 is more stringent, and technically accurate, than that contained in IWP-4500. .

The NRC has approved the use of ASME/ ANSI OMa-;988, _ Part 6 (OM-6), as an alternative rule in lieu of Subsection IWP of Section XI through approval of "

Code Case N-465, " Alternative Rules for Pump Testing,Section XI, Division l.

The NRC's approval was provided in Regulatory Guide (RG) 1.147, " Inservice Inspection Code Case Acceptability ASME Section XI Division 1," Revision 8, November 1990, by footnote 6 of 10 LFR 50.55a. In final rulemaking effective September 8,1992, which was published in the fMani Reaister-(57 FR 34666) on August 6, 1992, the staff approved the 1989 Edition of ASME,Section XI, which references OM-6 as alternative rule for inservice testing of pumps. _ The L.aff imposed no limitations to OM-6 associated with testing. pumps. However, in order to implement OM-6 under RG 1.147, the testing must comply with all of the requirements, or relief is required. -

10 CFR 50.55a(f)(4)(iv) provides that inservice tests'of pumps may' meet the requirements set forth in subsequent Editions and Addenda that are I incorporated by reference in 10 CFR 50.55a(b), subject to the limitations and L modifications listed, and subject to Commission-approval. Portions of editions or addenda may be used provided that all related requiremer.ts of the respective editions or addenda are met.

Provided the licensee meets all portions of-0M-6 related to vibration-test

( requirements, the proposed alternative to use a po'rtion of the latest edition L of the code is approved pursuant to 10 CFR 50.55a(f)(4)(iv)'for implementing the vibration testing requirements of IWP-4500 for pump inservice testing.

2.2 Relief Request PR-07 p Relief Request No. PR-07 requests relief from the upper limits on both the -

, acceptable range (1.02 times the reference differential pressure)_andLthe alert range (1.03 times the reference differential pressure) as'specified in:

Table IWP-3100-2.

2.2.1 Licensee's basis for relief The licensee states:

r High differential' pressure detected.during pump testing is a'p~oor-indicator of pump degradation as pump performance'does not-improve with-time. Adherence.to the Code specified alert and required ~ action ranges-L can result'in' unnecessary pump retesting and/or repair. ANSI /ASMEL L Operation and Maintenance. Standard (OM-6), now incorporated.into_the-

1989 edition of ASME Code,Section XI, has raised the upper required-_

l action-range to 1.1 times the reference differential pressure for all pump' types. This higher limit was based in part'-on the-recognition:that improved vibration monitoring is a better indicator of pump _ degradation.

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g The Brunswick Plant has previously committed to implementing OM-6 for .

vibration monitoring in pump relief request PR-01,' approved by the NRC in_ a Safety Evaluation issued January 4,1990, for the Second Ten-Year Inservice Testing Program.

2.2.2 Alternative testing The upper limit for the acceptable range will be 1.07 times the reference differential pressure. The upper limit for the alert range will be 1.1 times the reference differential pressure.

2.2.3 Evaluation of Relief Request PR-07 The Code requirements for establishing alert and required action ranges are to ensure that increased testing or required corrective actions are taken when pump test results indicate degrading performance. Generally, a pump will not indicate improved performance (increased flow rate results); therefore, the

!- upper limits are established to indicate that a problem in the test method or test instrumentation exists, rather than a degrading condition in the pump itself. A flow rate increase of 2% to 3% may not be indicative of an actual problem. A 10% increase in pump differential pressure would be a reasonable margin for the upper limit requiring corrective action to assess what condition, such as instrument fluctuations, has caused the increase, as supported in a later Code edition which has been approved by NRC.

The requirements of Table IWP-3100-2 were changed in OM-6 based on the general consensus that test failures that resulted from " higher than reference value" hydraulic measurements were caused by instrument fluctuations. The "high" alert values for hydraulic parameters were deleted. The "high". required action values were increased from 1.03 to 1.10 times reference value. The "high" required action values were maintained to assure test repeatability, thereby maintaining the quality of the hydraulic testing of the pumps. The lower limits for pressure (previously,Section XI required differential pressure measurements for positive displacement pumps) were increased for positive displacement pumps. For centrifugal pumps, the differential' pressure alert range was eliminated and the lower required action limit of 0.90 was maintained. These changes were based, in part, on an increased emphasis on improved vibration monitoring for evaluating pump condition and. operability.

The NRC approved the use of OM-6 as an alternative rule for pump testing in Revision 8 (November 1990) of RG 1.147 Code Case N-465, and by incorporation of the 1989 edition of Section XI in 10 CFR 50.55a(b) by rulemaking effective September 8,-1992.

Because the licensee will meet the high differential pressure required action range specified in Section 6.1 of OH-6, pursuant to 10 CFR 50.55a(f)(4)(iv),

the staff approves the proposal for use of a portion of the' latest edition of the Code approved in 10 CFR 50.55a(b).

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1 2.3 kelief Request VR-32  ;

Relief Request No. VR-32 requests relief from the Code requirement to quarterly full stroke to the open position the feedwater containment isolation check valves by passing the maximum required accident flow through the check valves.

2.3.1 Licensee's basis for relief 1

The licensee states:

There is no external / remote means to verify the valve position during- .j system operation, nor is there an external means to manually cycle the valves. NRC Generic letter [GL) 89-04 requires verification of full . l stroke to the open position by passing maximum accident' flow through the check valve. The HPCI [high pressure coolant injection) and RCIC

[ reactor core isolation cooling) Systems inject into the feedwater _ lines up-stream of these valves (HPCI in A loop and RCIC in B loop). The-HPCl_ ,

system accident flow requirement is 4250 gpm [g.allons per minute); the '

RCIC System accident flow requiremert is 400 gpm. During normal plant operation, the feedwater flow is approximately 12,500 gpm per loop.

Since normal plant operation passes 12,500 gpm, which is greater than -,

the maximum accident flow of either the HPCI or RCIC Systems, through these check valves, full stroking of valves to the open position is verified by normal plant operation.

2.3.2 Alternative-testing None. Full-stroke exercising of valves to the open position is inherently verified during normal plant operation.

2.3.3 Evaluation of Relief Request VR-32 As stated in position 1 of GL 89-04, " Guidance on Developing Acceptable-Inservice Testing Programs"':

A check valve's full stroke _to the open position may be verified by-passing the maximum required accident ' condition flow through 'the _ valve.

Since normal plant operation passes approximately.12,500 gpm through these

-check valves, which is greater than the maximum accident flow of either_ the -

HPCI or RCIC systems, full-stroking of these valves to the open position (to verify that they can pass the maximum' accident flow)-is verified by normal' plant operation. This is consistent with the provisions of GL 89-04_and therefore, satisfies the quarterly test requirement--of._Section XI of the ASME..

Code.

As stated in IWV-3414, valves which operate in.the course.of plant operation at a frequency which would satisfy the exercising requirements need not be additionally exercised, provided that the observations otherwise: required for testing are made and analyzed during such opera _ tion and are recorded.in the plant record at intervals no greater than as specified in IWV-3411.

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The testing requirements of the Code are satisfied by normal _ operation; therefore, relief is not required. The licensee should ensure that the requirements of IWV-3414 for observations and recording are met.

2.4 Relief Request VR-33 Relief Request No. VR-33 requests relief from the Code requirement to quarterly full stroke exercise to the open and closed positions the RCIC injection containment isolation check valve.

2.4.1 Licensee's basis for relief The licensee states:

There is no external / remote means to verify valve position. The only.

way to full-stroke test this valve to the open position during plant-operation is to initiate the RCIC system and inject into the reactor vessel. Introducing non-preheated water into the reactor vessel requires the vessel shell temperature to be less than 200*F to limit possibility of thermal shock, which could cause' reactor vessel nozzle cracking. During normal cold shutdown, the reactor vessel shell temperature does not fall below 200*F.

The RWCU [ reactor water cleanup) system, which is normally operating, also injects through this valve. RWCU system design flow is-200 gpm; the RCIC system design flow is 425 gpm. Therefore, partial valve stroke is inherently verified during plant operation.

2.4.2 Alternative testing The valve closed position is verified by leak testing during refueling in accordance with 10 CFR Part 50, Appendix J. The check valve is incorporated into a disassembly program which meets the guidance of GL 89-04. Upon disassembly, the valve will be visually examined and manually cycled.

2.4.3 Evaluation of Relief Request VR-33 The staff agrees that it would be impracticable to full-stroke test this valve to the open position during normal plant operation because it would require initiation of the RCIC system and injection of relatively cold water into the reactor vessel. Introducing non-preheated water into the reactor vessel requires the vessel shell temperature to be less than 200*F to limit possibility of thermal shock, which could cause reactor vessel nozzle cracking. Since the plant is not normally maintained in cold shutdown for- an appreciable period of time, the reactor vessel shell temperature does not normally fall below 200*F. It would, therefore, be impracticable or unnecessarily burdensome to require the testing of this valve during the brief periods that the plant is in_this transition mode. The RWCU-system injects primary water into the line upstream of this check valve. The RWCU' system is generally in service during power operations and during cold ~ shutdowns.

Therefore, E51-V88 is open during these plant conditions to allow RWCU_ flow to -

continue, making it impractical to perform closure verification by a leakage-test during power operations or cold shutdown. However, the RWCU flow is not sufficient to full-stroke the check valve.

B GL 89-04, Position'2, " Alternate-to Full Flow Testing of Check Valves,"

states:

The NRC staff position is that valve disassembly and inspection can be used as a positive means of determining that a valve's disk will full- ,

stroke exercise open or of verifying closure-capability, as permitted by .

IWV-3522. If possible, partial valve stroking quarterly or during cold.

shutdowns, or after reassembly must be performed.

Since this check valve is included in the licensee's disassembly program, which is stated to meet the guidance of GL 89-04, and since this check valve is at least partially-stroked open during normal operation via RWCU System flow and closure is verified via Appendix J leak testing each refueling, the staff concludes that the e dance of Position 2 of GL 89 04 has been met, implementation of the lict..isee's check valve disassembly program and compliance with GL 89-04 are subject to NRC inspection.

By issuing GL 89-04, the staff concluded that if the guidelines of Position 2 are followed, relief would be granted pursuant to 10 CFR 50.55a(f)(6)(i).

As indicated in GL 89-04, relief to use the proposed method, in lieu of-full-stroke exercising the check valve to the.open position with flow, was granted provided the guidance directed in position 2 is followed. No further.

evaluation is required.

2.5 Relief Request VR-34 Relief Request No. VR-34 requests relief from the Code requirement to quarterly full-stroke exercise to the open and closed positions for High Pressure Coolant Injection (HPCI) isolation check valve E41-V159, 2.5.1 Licensee's basis for relief The licensee states:

l The only way to cycle valve during plant operation is to initiate the HPCI System and inject into the reactor vessel. Introducing.non-preheated water into the reactor vessel requires the vessel shell l

temperature-to be less than 200'F to limit possibility of thermal shock, which could cause reactor vessel nozzle cracking. During normal cold shutdown. the reactor vessel shell temperature does not fall below 200*F.

During unit shutdown, tha valve can be manually exercised;'however, the valve is located in the (main steam isolation ~ valve] _MSIV pit. Access requires the_ lifting of the MSIV plug, which is not a normal cold shutdown activity.

2.5.2 Alternative testing Manually full-stroke exercise to the open and closed position at each refueling.

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N 1.5.3 Evaluation of Relief Request-VR-34 The Code,Section XI, ~ IWV-3500,' r_equires that " check valves shall be exercised-at least once every 3 months, except'as provided by IWV-3522." IWV-3522 3

- states: " Valves that cannot be exercised during plant operation shall be specifically identified by the owner and shali be full-stroke exercised during cold shutdowns."

The licensee indicated in the relief request that, although the valve can bel manually-exercised in accordance with the Code, because of the valve's

' t r location, it is impracticable to cycle-the_ valve at the frequency specified by the Code. That is, the valve is located in the MSIV. pit., Access to the MSIV

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pit requires lifting-of the MSIV plug, which is not a normal cold shutdown 5  :

s activity. Therefore, the licensee requests relief from the. test-frequency 1  :

specified by the Code and proposes to test this valve at each' refueling cutage- '

when the MSIV-pit is accessible. l Requiring that the MSIV pit plug be removed, in order to test-the HPCI ..  :

injection isolation check valve, each time'the plant is taken to cold shutdownT  ;

could unnecessarily delay plant startup;and would unnecessarily. expose L maintenance / test _ personnel to ionizing radiation.

In rulemaking to 10 CFR 50.55a effective September 8, 1992'(See'57 FR 34665),-

the 1989 edition of ASME.Section'XI was incorporated in-10 CFR 50.55a(b).~ The- ' ,

g 1989 Edition provides that' the rules for inservice testing of valves = are as l

specified in 0M-10._ The staff imposed no-limitations'to 0M-10 associated with testing valves.during-cold shutdown. 10 CFR-50.55a(f)(4)(iv) provides-that- ' '

inservice tests-of 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 thr limitations'and modifications listed,-and subject to: Commission _-

approval. Portions of editions or addenda may be used-provided that-all related requirements _of the respective editions or addenda are met. - OM-10,' _ .

Paragraphs 4.3.2.2 (e) states: "if_ exercising is not practicable during_ plant

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~ operation or cold shutdown, it may- be limited to full; stroke during. refueling

- outages." As stated above, OM-10 has been approved by the NRC: staff _as-providing an acceptable level of safety.

1 Pursuant'to 10 CFR 50.55a(f)(4)(iv) the staff approves the implementation.of-the requirements of OM-10, Paragraph 4;3.2.2_(e), for inservice testing of-check valve E41-V159. <

2.6 Relief

Request VR-35 -

- Relief Request No..VR-35 requests relief from the.C' ode requirement to quarterly full stroke to-the open position' the service water, system-to well E water : isolation check valves SW-V144- and SW-V148. These valves check reverse; flow' to isolate the service water system from'well-water in'_the event of a -

-well_ water line break. , -

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2.6.1 Licensee's basis for relief i

The licensee states: j 1

There is no external / remote means to ve;ify valve position.during system H operation nor is there an external means to manually cycle the valves.

There are no vent paths upstream of the check valves to perform a reverse flow test. The testing of these valves requires opening of the system upstream of the valves. Downstream of the valves there are no I isolation valves to isolate the Service Water System in case a check valve falls to close.

2.6.2 Alternative testing i

The valves will be incorporated into a disassembly program, which meets the  ;

guidance of GL 89-04. Upon disassembly, the valves will be visually examined and manually cycled.

2.6.3 Evaluation of Relief Request VR-35

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1 The design of the system does not enable testing the closure function of the service water /well water isolation check valves. There are no test taps or

vent valves that would provide r w .as to perform a leakage test, and there l are no pressure indicators upstron.i of the valves which could indicate closure. The licensee indicates that testing these valves requires opening the system upstream of the valves and implies that this could result in reverse flow of service water to the well water system if one or both valves failed to close.

While this test could result in undesirable conditions during power operations and potentially delay startup from a cold shutdown condition, it is not clear.

fron the description in the relief request why this test would be impractical' <

to perform during a refueling outage condition during a period when the ~ '

service. water system is pressurized, creating l sufficient backpressure to close-the valve. The licensee could have taken one of the following actions in-l order to resolve this issue: .-(l) if this type of testing could be performed L during refueling outage conditions, the licensee should implement the testing' .

rather than employing a-disassembly and inspection- program for inservice testing of these valves, or, (2)'if the' licensee determines that-this is impractical, the relief request should be revised to discuss the details in

-the " Basis for Relief" and continue to implement the disassembly and-inspection program in accordance with the guidelines of'GL 89-04, Position 2.

By issuing GL 89-04, the staff concluded that if the guidelines of Position 2 are followed, relief would be granted pursuant' to 10 CFR 50.55a(f)(6)(i)).

In a telephone conversation between the licensee and the NRC staff on October 29, 1992, the current statas of inservice testing for these valves was i discussed. Both of these valves on Unit 2 have been disassembled and

, inspected. 'One of-the two valves on Unit I has been disassembled and inspected within the last two years. The remaining valve on Unit l_is scheduled to be disassembled and inspected during the_next refueling outage, l currently scheduled for the Fall of 1993. All ~ four valves have the same

(= -manufacturer and service conditions. The licensee-stated that the one valve

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- that has not yet been inspected is believed to be operable a.nd capable of performing its safety function based on the fact that", hen.the.other three-valves were inspected there was no binding, the disks swung freely, and th1re were no repairs required. The licensee stated that these valves wil! be incorporated into a disassembly program, consistent with Position 2 of GL 89-04.

As indicated in GL 89-04, relief to use the proposed testing is granted pursuant to 10 CFR 50.05a(f)(6)(i). The licensee could, however, assess if-another test method is practical as discussed in Section 2.6.3 above.

2.7 Relief Request VR-36 Relief Request Na, VR-36 requests relief from the Code requirement to quarterly full stroke exercise to the open position RCIC to RWCU system isolation check valve G31-F039. This valve prevents reverse flow to ensure water is not directed to the RWCU system when RCIC injection is ruquired.

2.7.1 Licensee's basis for relief The licensee states:

This valve has to close upon RCIC System injection to ensure water is not directed into the Reactor Water Cleanup System.

There is no external / remote means to verify the check valve's position-during normal operation, nor is there an external means to cycle the valve while the system is shut down.

Tu verify the valvo's ability to close requires pressurizing downstream of the valve and observing the pressure upstream. There are nu. test connections that will allow this pressurization._ Pressurizing the pipe will require initiating the RCIC System and injecting into the reactor vessel. In order to initiate the RCIC System, the plant is required to-be operating (producing steam). Introducing non-preheated water into the reactor during nperation could reduce power and cause reactor vessel-nozzle cracking due~ to thermal shock. During cold shutdown, the shell temperature does not normally fall below 200*F, which is-the-upper-temperature limit to avoid thermal shock when introducing non-preheated.

water.

2.7.2 Alternative testing The valve will be incorporated into a disassembly program which meets the guidance of GL 89-04. Upon disassembly, the valve will be visually examined and manually cycled.

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2.7.3 Evaluation of Relief Request YR-:i6 ,

The ASME Code, Ser. tion XI, IWV-3500, requires that " check valves shall be exercised at least onc( every 3 months, except as orovided by-IWV-3522."_ IWV-3522 states: " Valves that cannot be exercised during pla.nc operationLshall be - -

specifically identifled by tne Owner and s%11 be full-stroke exercised during cold shutdowns." Position 2 of GL 89 04 states that "iialve disassembly and inspection can be used as a posit 19e means of determining that a valve's disk -

will full-stroke e:rarcise open or of verifying closure capability, as permit;ed by IWV-3522. If possible, partial valve stroking quarterly or during cold shutdowns, or after reassembly must be performed."

for RWCU check valve G31-F039, exercising in accordance with the Code requirements is not practical. There are no test connections insta' lied that' enable leak testing. Duricg pcwer operations and cold. shutdown conditions, the RCIC systee cannot be pressurized to reverse check this valve without injecting into the reactor vessel, which is not practical. Therefore, the only practical method to verify the valve is capable of closing and seating is to disassemble and inspect the Internals.- The licensee should follcw indurtry developments that would enable verification with a non-intrusive method such-as radiography or thermography.

Since this check valve will be included in the licensee's disassembly program (which is stated to meet the guidance of GL '89-04) relief is approved pettG1 89-04, implementation of the licensee's check valve disassembly program and compliance with GL 89-04 are_sunject to NRC inspection. By issuing GL 89-0a, the staff concluded that, if the guidelines of Position 2 are followed, reliv.f-would be granted pursuant to 10 CFR 50.55a(f)(6)(i).

As indicated in GL 89-04, relief to use the proposed testing was granted parsuant to 10'CFR 50.65a(f)(6)(i). '

2.S Relief Request VR-37 Relief Request No. VR-37 requests relief from defining and verifying maximum accident condition flow for all nitrogen and air supply check valves. IWV-3500 requires a quarterly full-stroke exercise. Position 1 of GL 89404 d3 fines full stroke as the valves ability to pass maximum accident flow conditions. The nitrogen and air supply system check valves must-upen to

! allow air or nitrogen flow. There'is no external / remote means to verify valve-position.

K l 2.8.1 Licensee's basis fer relief i

The licensee states: '

l Relief is requested from defining .and verifying maximum accident j condition flow for all nitrogen and air safety check valves.

Defining and verifying full flow through small check valves in air and l _ gas systems is typically impractical.

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I the design function of check valves installed in air and gas systems is.

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to regulate pressure, not flow. These valvas wili enly open e n a differentitu pressure exists across the valve, in which case the valve 6 is only required te open enout]h co re-establish the pressure. The valves are fonctionaily testod during their associated compunent and/or

{i syst9m test, Defining and trying te verify eximta accident flow j through the check valve would not provide add \tional assurance of the essoc*ated components operability.

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d Disassembly of thase check va!vas to verify full stroke is-cot practicai gi due to their size (i.e., primarily 1/4 inch valv9s) and design.

3 2.8.1 Alternative testing ,

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j All safety-related check valves in air and/or gas systems will be tunctionally r , tested during their assocsated component and/or systems test. Opening and/or-  %

= closing of these valves will be verified, as applicable, during these totts. 4 2.8.3 Evaluation of Relief Request VR-37 i -

The Code, Sectica XI, IWV-3500, requires that " check valves shall be exercised [J

,.- at least once every 3 months, except as provided by IWV-3522." IWV-3522 U  ?

_- states: " Valves that cannot be exercised 6uring olant operatic, shall be ,

specifically identified by the Owner and shall be full-stroke exercised during.

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.. cold shutdowns." Position 1 of GL 89-04 defines full-stroke as the valves eF, obility to pass maximum accident flow condicians. The licensee proposes to u c-  : functionally test all safety-related check valves in the air and/or gas ,

[ systems during thcir associated component and/or system test.

Disassembly of these check valver, to verify full stroke is not practical due

to their size (i.e., primarily 1/4 inch valves) and design. In fact, y

disassembly and inspection of these small check valves would prcbably increase the likelihood of their failure and result in a decrease in safety.

Furthermore, defining and trying to verify .naximum accident flow through- the check valve would not be practicable (i.e., would impose an undue hardship on ,'

y the licansee) ard would not' provide additional assurance of the assuciated?

componcrts operability.

Since the design function of the check valves installed in air and gas systems  ?

is to regulate pressure, not flow, these valves will only open when there is a differential pressure across the valve, and then the valve will open as much, . 3 and for as long, as is necessary to reestablish the pressure. Full stroke of these check valves may not be required under accident conditions.

Functionally testing all-safety-related chect valves in the air and/or gat systems during their associated component and/or system test provides reasonable assurance of operational readiness and verifies that these valves stroke to the position required to fulfill their safety function. OM-10, Paragraph 4.3.2.2, requires that check valves be exercised to the closed, full open, or partially open position required to fulfill their safety function.

Therefore, because a partial stroke of these valves meets the requirements, the staff may approve application of this pertion of OM-10.

1 l

Pursuant to 10 CFR 50.55a(f)(4)(iv), the staff approves the implementation of the requirements of OM-10, Paragraph 4.3.2.2, for inservice testing of the nitrogen and air supply system check valves.

3.0 CollCLUSION in evaluating the licensee's requests for relief from the requirements oi-Section XI the staf f considered (1) the acceptability of proposed alternative testing, (2) whether the hardship of compliance is without a compensating increase in safety, and (3) the impracticality of performino the required testing considering the burden if the requirements were impe,ed. For the relief granted under Generic Letter (GL) 89-L1, pursuant to 10 CFR 50.55a(f)(6)(1), the staff has determined that granting relief is authorized -

by law and will not endanger life or property, or the common defense and security, and is otherwise in tne public interest. The granting of relief or authorization of proposed alternatives is based upon the fulfillment of any commitments made by the licensee in its basis for each relief request and the -

proposed alternate testing.

Principal Contributor: D. Fischer Date: February 11, 1993

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