ML20059B277

Safety Evaluation Accepting IST Program Relief Requests

ML20059B277
Person / Time
Site:	River Bend
Issue date:	10/22/1993
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20059B263	List: ML20059B261 ML20059B277
References
NUDOCS 9310280115
Download: ML20059B277 (11)

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[ WASHINGTON, D.C. 2055MX)01 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION BELATED TO THE INSERVICE TESTING PROGRAM RELIEF RE0 VESTS GULF STATES UTILITIES COMPANY RIVER BEND STATION DOCKET NO. 50-458

1.0 INTRODUCTION

By letter dated February 1,1993, Gulf States Utilities Company (GSU) submitted Revision 6 to the River Bend Station Inservice Testing (IST) program. By letter dated January 2,1991, the staff issued a Safety Evaluation (SE) with a technical evaluation report (TER) which covered the first ten-year IST interval. The licensee was requested to address 26 action items from that TER. The licensee responded to those action items in a letter dated July 26, 1991. By letter dated February 11, 1992, the licensee requested an extension of interim relief for relief requests VRR-2, VRR-24, and VRR-29, revised relief requests PRR-2, PRR-3, PRR-4, and VRR-63 for clarity, and included one new relief request, VRR-64. The staff responded to the July 26, 1991 and February 11, 1992, letters in a SE dated July 16, 1992.

The licensee revised their IST program and submitted Revision 6, which contained two new relief requests, VRR-65 and VRR-I-01. Evaluations of relief requests PRR-4 and VRR-24, which were revised in Revision 6, and relief requests VRR-65, and VRR-I-01, are included below.

2.0 BACKGROUND

The Code of Federal Regulations,10 CFR 50.55a, requires that inservice testing (IST) 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 relief has been requested and granted or proposed alternatives have been authorized by the Commission pursuant to 10 CFR 50.55a(a)(3)(i), (a)(3)(ii), or (f)(6)(1). In order to obtain authorization or relief, the licensee must demonstrate that: (1) conformance is impractical for its facility; (2) the proposed alternative provides an acceptable level of quality and safety; or (3) compliance would result in a 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 i 10 CFR 50.55a(b), subject to the limitations and modifications listed, and subject to Commission approval. NRC guidance contained in Generic Leter (GL) 89-04, " Guidance on Developing Acceptable Inservice Testing Programs,"

provided alternatives to the Code requirements determined to be acceptable to the staff and authorized the use of the alternatives in Positions 1, 2, 6, 7, 9, and 10 provided the licensee follows the guidance delineated in the 9310280115 931022 0 PDR ADOCK05000458y p PDR d

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applicable position. When an alternative is proposed which is in accordance with GL 89-04 guidance and is documented in the IST program, no further evaluation is required; however, implementation of the alternative is subject to NRC inspection.

Section 50.55a authorizes the Commission to grant relief from ASME Code requirements or to approve proposed alternatives upon making the necessary '

findings. The NRC staff's findings with respect to granting or not granting the relief requested or authorizing the proposed alternative as part of the licensee's IST program are contained in this Safety Evaluation (SE).

In rulemaking to 10 CFR 50.55a effective September 8,1992, (see 57 FR 34666),

the 1989 Edition of ASME Section XI was incorporated in 10 CFR 50.55a(b). The 1989 Edition provides that the rules for inservice testing of pumps and valves shall meet the requirements set forth in ASME Operations and Mair.tenance Standards Part 6 (OM-6), " Inservice Testing of Pumps in Light-Water Reactor Power Plants," and Part 10 (OM-10), " Inservice Testing of Valves in Light-Water Reactor Power Plants." Pursuant to 10 CFR 50.55a(f)(4)(iv), portions of editions or addenda may be used provided that all related requirements of the respective editions or addenda are met, and subject to Commission approval.

Relief is not required for those inservice tests that are conducted in accordance with OH-6 and OH-10, or portions thereof, provided all related requirements are met. Whether all related requiremer.).s are met is subject to NRC inspection.

i 3.0 REVISED RELIEF REQUESTS 3.1 Relief Recuest PRR-4 The licensee has requested relief from the Code full-scale range requirements of ASME Section XI, Paragraph IWP-4120, for pumps in the following systems:

diesel generator and auxiliary emergency; low pressure core spray, normal service water; reactor core isolation cooling; residual heat removal; standby liquid control, and standby service water. The Code requires that the full-scale range of each instrument shall be three times the reference value or less. The licensee has proposed to use one gauge to read both idle and running suction pressures rather than two gauges which are necessary to meet the range requirements of IWP-4120.

3.1.1 Licensee's Basis for Reauestina Relief -

The licensee stated "For pumps in the IST program, when trying to obtain idle and running suction pressures, the following problems are encountered:

In these tests, the procedures require the use of temporarily installed M&TE instead of the plant installed instruments. The M&TE at River Bend Station comes in standard full-scale ranges (e.g.: 0-15, 0-30, 0-60, 0-100, 0-150, etc).

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1. Certain pumps have very low idle and running suction pressures (1.5 to 4.21 psig) which causes a problem obtaining the requirement of IWP-4120. i The lowest pressure gauges available are 0-15 psig. ,

2. The second problem occurs when obtaining the idli and running suction  :

pressure due to the disparity in the pressures. The idle pressure for i example is 22.5 psig and the running pressure is 100.6 psig. In order to  !

be in compliance with IWP-4120 it makes it necessary to use two gauges to  ;

accomplish this. In certain cases the pumps are located in contaminated i areas or the fluid in the piping syste.a can not be spilled on the floors I which causes great hardships for testing personnel and additional load on '

radwaste processing. Therefore, the use of one gauge, which would be practical, would not be allowed by IWP-4120.

3.1.2 Alternative Testino {

The licensee proposed to use p_01 gauge for pressure readings in lieu of attaching, using, and removing two separate gauges. In addition, the licensee  ;

requested a 10 percent deviation in the full-scale range requirements of  ;

IWP-4120.

1 3.1.3 Evaluation In the staff's SE dated January 2,1991, interim relief was granted to PRR-4 $

in order to allow the licensee additional time to provide more specific  :

information to enable the staff to complete the evaluation. The licensee  !

t revised and resubmitted this relief request with the responses to the TER anomalies in a letter dated July 26, 1992. The revised relief request again did not list the specific gauges that did not meet the Code requirements. l Therefore, the relief request was denied. Revision 6 of the IST Program Plan  :

for River Bend Station contained another revision to PRR-4. Once again, the '

revised relief request did not specifically identify the gauges for which the licensee was requesting relief from the Code requirements. ,

In NRC Inspection Report 50-458/93-05, dated April 30, 1993, the Resident j Inspector conducted a review of Revision 6 of the licensee's IST program. In r response to questions about relief request PRR-4, the licensee stated that the ,

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Code requirements could probably be met and that the 10 percent deviation tolerance from the requirements of IWP-4120 was an arbitrary number and a i study had not been conducted to determine how many gauges would be affected by the tolerance. These statements by the licensee are inconsistent with the  ;

basis for relief included in Relief Request PRR-4. .

t In rulemaking to 10 CFR 50.55a effective September 8, 1992, (57 FR 34666), the i 1989 Edition of ASME Section XI was incorporated in (b) of 550.55a. The 1989 a Edition provides that the rules for inservice testing of pumps may meet the  ;

requirements set forth in OM-6. Pursuant to 10 CFR 50.55a(f)(4)(iv), portions  !

of editions or addenda may be used provided that all related requirements of the respective editions or addenda are met, and subject to Commission >t l

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o-4 approval, and therefore, relief is not required for those inservice tests that :

are conducted in accordance with OH-6 or portions thereof. The suction pressure measurement requirement was originally established in ASME Section XI, Subsection IWP, to aid the licensee in establishing adequate ,

suction pressure conditions to perform IST. OH-6 does not require suction pressure measurement because, as stated in NUREG/CP-0111, " Proceedings of the Symposium on Inservice Testing of Pumps and Valves," page 36, the Code Committee recognized that the owner is responsible to address testing limitations and that those limitations should be written into the test procedures. Therefore, suction pressure measurement is no longer required to satisfy inservice testing requirements.

The staff had a teleconference with the licensee on August 6,1993, in which the licensee stated that they intended to adopt the OM-6 requirements related to inlet pressure measurement. The licensee stated that, since OH-6 does not require a static pump suction pressure, the Code requirements could be met for all pump pressure gauges in the licensee's IST program. The staff informed the licensee that if they determine that static suction pressure will no longer be measured, the reasons should be documented in the licensee's IST program. However, if suction pressure is used to calculate the pump differential pressure, the suction pressure gauge must meet the instrument requirements specified in the Code, including the appropriate range for the  !

reference value.

3.1.4 Conclusion Based on the deletion of inlet pressure measurement in OM-6, the licensee may request to follow OH-6 and no longer measure inlet pressure. Deletion of inlet pressure measurement is approved pursuant to 10 CFR 50.55a(f)(4)(iv) ,

except where the licensee uses inlet pressure to calculate differential pressure. The licensee stated in the August 6, 1993, teleconference that the pressure gauges for all pumps in their IST program meet the Code requirements for measuring the running suction (inlet) pressure which is used to calculate differential pressure. Therefore, this relief request pertaining to instances in which inlet pressure is used to calculate differential pressure should be deleted and the use of the requirements of OH-6 which allow deletion of the measurement should be included in the IST program document.

3.2 Relief Reouest VRR-24 ,

The licensee has requested relief from the Code exercise frequency ,

requirements of Section XI, Paragraph IWV-3521, for the check valves listed below. These check valves are contained within the following systems: closed cooling water (CCW), floor and equipment drains (FED), residual heat removal -

low pressure coolant injection (RHR-LPCI), reactor core isolation cooling (RCIC), HVAC chilled water (HVAC-CW), main steam isolation and penetration valve leakage control (MSIV and PVLC), main steam (MS), and reactor plant sampling (RPS). The Code requires these check valves to be exercised at least once every 3 months. The licensee has proposed categorizing identical valves into groups and disassembling and inspecting specific check valves in each l

group during refueling outages on a rotational basis.

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M Check Valve System Safety inspection Refueling Valve Size / Position Group Outage Number Type 0-open Number Inspection C-closed Schedule ICCP*V337 2"/1 CCW C 1 6,8 2"/l 1CCP*V338 CCW C 1 5,7 10FR*V78 4"/2 FED C 2 5,8 IDFR*V79 4"/2 FED C 2 6 IDFR*V87 4"/2 FED C 2 7 1DFR*V88 4"/2 FED C 2 5,8 10FR*V97 4"/2 FED C 2 6 1DFR*V98 4"/2 FED C 2 7 IDFR*V107 4"/2 FED C 2 5,8 IDFR*V108 4"/2 FED C 2 6 IDFR*Vll7 4"/2 FED C 2 7 1DFR*Vil8 4"/2 FED C 2 5,8 IDFR*V127 4"/2 FED C 2 6 1DFR*V128 4"/2 FED C 2 7 1E12*VF084A,8,C + 1.5"/l RHR-LPCI C/0 3 5,7 lE1?*VF085A,8,0 + 1.5"/1 RHR-LPCI C/0 3 6,8 IE51*VF030 6"/3 RCIC C/0 6 5,6,7,8 1HVK*V48 2"/l HVAC-CW 0 1 7 IHVK*V97 2"/l Ht'AC-CW 0 1 5,8 ILSV*V12 1"/l MSIV & PVLC 0&C 4 7 ILSV*V35 1"/1 MSIV & PLVC C 4 5,8 ILSV*V36 1"/4 MSIV & PLVC C 9 6,8 ILSV*V42 1"/l MSIV & PLVC C 4 6 ILSV*V46 1"/l MSIV & PLVC C 4 5,8 ILSV*V72 1"/4 MSIV & PLVC C 9 6,8 ILSV*V76 1"/4 MSIV & PLVC C 9 5,7 5,7 ILSV*V90 1"/4 MSiv & PLVC C 9 ~

ILSV*V114 1"/l MSIV & PLVC C 4 i6 ILSV*V120 1"/1 MSIV & PLVC C 4 7 ISVV*V122 1.5"/l MS C 5- 5,6,7 ISVV*V123 1.5"/l MS C S 5,6,7 ISSV*V129 1.5"/l MS C 5 5,6,7 ISSV*V130 1.5"/l MS C 5 '5,6,7 ISSR*V705 1.5"/l RP[S 0 7 5,6,7,8 Key to valve types 1 - 600 lb class piston type 2 - 150 lb class spring loaded piston type 3 - 150 lb class swing type 4 - 1500 lb class spring loaded piston type

+ The licensee states: "For these check valves between the line-fill pumps and the process lines, only one of the pairs of valves (i.e. VF084A and VF085A) is required to be disassembled. However, if the valve tested fails, then both of the valves in the pair need to be disassembled, tested, and reworked if necessary."

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3.2.1 Licensee's Basis for Reo'Lestina Relief The licensee stated "For valves that cannot be exercised during plant operation as specifically identified in the relief request, the required full-stroke exercise testing of the valves during normal operation would require the systems to be made inoperable. The design of the associated system in each case is such that normal test methods are inadequate to confirm the test results. The valves are either back-to-back with no test connection between them or the pipe segment cannot be isolated. Therefore, these valves cannot be individually tested and verified operable by normal test methods.

An internal visual inspection and manual exercise of the disk will verify operability. This disassembly requires a refueling outage in order to provide adequate time for planning and implementation without impacting plant startup. l Note: ASME OM Code-1990, Section ISTC 4.5.4(c) allows disassembly every refueling outage as an alternative to quarterly testing using normal test methods.

In NRC Generic Letter (GL) 89-04, dated April 3, 1989, Position 2,

' Alternative to Full Flow Testing of Check Valves,' the NRC Staff position is that valve disassembly and inspection can be used as a positive means of determining that the valve's disk will full stroke exercise open or of verifying closure capability, as permitted by IWV-3522."

3.2.2 Alternative Testina The liceasee proposed "An internal visual inspection and manual exercise of the check valve disk in accordance with the ASME OM Code 1990, ISTC-4.5.4(c) and Generic Letter No. 89-04, Position 2, to the following schedule:

First refueling - all check valves listed Second and subsequent refuelings - a sampling of the list of check valves consisting of at least one third [of the] valves from each group designated.

These valves are grouped together by similar design (manufacturer, size, model, number, and material used in construction) and similar service condition.

A different valve of each group is required to be disassembled, inspected, and manually full-stroked at each refueling, until the entire g'roup has been tested. If it is found that the disassembled valve's full-stroke capability is in question, the remainder of the valves in that group shall be disassembled, inspected, and manually full-stroked at the same outage.

Note: River Bend Station [RBS) has a non-intrusive diagnostic check valve program in place. If a valve exhibits problems or failures more than once in a 10 year period, it will be placed into this performance monitoring program (PEP-0054, RBS Check Valve Program)."

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3.2.3 Evaluation The check valves listed in Section 2.2 of this SE are all piston type check valves with the exception of RCIC valve IE51*VF030 which is a swing type check valve. According to the licensee's IST program, most of the check valves have safety functions in the closed position. The licensee has indicated that all ,

these valves cannot be tested individually to determine valve degradation by '

normal test methods such as a local leak rate test.

The licensee has proposed to test these valves on a refueling outage frequency in accordance with the OM Code-1990, Section ISTC, Paragraph 4.5.4(c), and GL 89-04. Paragraph 4.5.4(c) is essentially the same as OH-10, Paragraph 4.3.2.4(c). OM-10 has been approved for use by the NRC in rulemaking that adopted the 1989 edition of ASME Section XI. However, OH-10, as well as ISTC, does not allow grouping similar check valves and inspecting one check valve from each group in order to satisfy the Code requirements.

GL 89-04, Position 2, " Alternative to Full Flow Testing of Check Valves,"

states 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 verify closure capability, as permitted by IWV-3522. In addition, GL 89-04 states that where the licensee determines that it is burdensome to disassemble and inspect all applicable valves each refueling outage, a sample disassembly and inspection plan for groups of identical valves in similar applications may be -

employed. Valves placed in one group should have the same design, service conditions, and orientation.

The licensee's disassembly and inspection program for check valves listed in the table is in accordance with the guidance of GL 89-04, Position 2, for inspection frequency. Even though group 2 contains 12 valves and group 4 contains 6 valves, the valves from these groups are inspected at least every '

fourth refueling outage. However, group 1 valves are not in the same system and therefore may not see the same service conditions. The licensee should ensure that all the valve groupings in this relief request conform to the guidance provided in GL 89-04, Position 2, or request specific relief to use a different criteria for grouping.

3.2.4 Conclusion Relief is granted to disassemble and inspect the check valves listed in this relief request pursuant to GL 89-04 and 10 CFR 50.55a(f)(6)(1) based on the impracticality of performing testing in accordance with the Code requirements, and in consideration of the burden on the licensee if the Code requirements were imposed on the facility. The relief is granted with the provision that the disassembly and inspection of the check valves listed in this relief request conform to the guidance provided in GL 89-04, Position 2. The implementation of this relief request is subject to NRC inspection. The licensee should update their IST valve table to reference all the valves that are covered under this relief request.

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4.0 NEW RELIEF RE00EST 4.1 Relief Recuest VRR-65 -

The licensee has requested relief from the Code test frequency requirements of ASME Section XI, Paragraph IW-3521, for the containment atmospheric sample return check valve ISSR*V706. The Code requires that the check valves be

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exercised at least once every three months. The licensee has proposed to i perform closure testing every refueling outage in conjunction with local leak rate testing.

4.1.1 Licensee's Basis for Reauestino Relief The licensee stated "This valve cannot be exercised in the reverse closure direction during normal plant operation which would require isolating this portion for an extended (beyond the LCO [ limiting condition for operation])

period."

4.1.2 Alternative Testina The licensee proposed "An exercise test to verify the valve opens is performed quarterly. The reverse closure will be verified during performance of a local leak rate test (LLRT) performed every refueling outage."

4.1.3 Evaluation The containment atmosphere sample return check valve is in the CMS sample return line from the sample station. This line connects the reactor plant sampling system to the containment atmosphere and leakage monitoring system.

The Code requires that these valves be tested to their safety position quarterly. The valve appears to have a safety function to close to prevent diversion of flow from the containment atmosphere and leakage monitoring system. The licensee currently conducts testing on this valve in the open direction quarterly. The licensee stated that closure testing cannot be conducted quarterly because the time required to test this valve in the closed direction would exceed the LCO specified in the licensee's Technical Specifications (TS). However, the licensee did not state the applicable LCO and the time required to conduct closure testing on this check valve. In addition, the basis for relief does not address the impracticality of conducting closure testing during cold shutdowns. Finally, the 11censee's IST program does not indicate that the closed position is a safety function which requires IST.

In a teleconference with the licensee on August 6, 1993, the licensee stated that there was no applicable LCO to this valve. Further study revealed that this valve could be tested to its safety function at the Code required '

frequency and relief was not required. The licensee committed in the teleconfernce to withdraw this relief request.

4.1.4 Conclusion According to the licensee, relief is not required to test this valve at the Code required frequency. In a letter dated September 14, 1993, the licensee withdrew Relief Request VRR-65.

5.0 INTERIM RELIEF RE0 VEST 5.1 Relief Reauest VRR-I-01 The licensee has requested relief from the Code test frequency and method requirements of ASME Section XI, Paragraphs IWV-3521 and IWV-3522, for the recirculation pump mechanical seal sealing water supply drywell isolation check valves IB33*VF013A, 1833*VF013B, IB33*VF017A, and IB33*VF178. The Code requires these valves to be exercised at least once every 3 months. These valves have a safety function to close to prevent drywell bypass leakage. The licensee has proposed to verify that these check valves close by non- ,

destructive means every refueling outage until vent lines can be installed to facilitate closure testing.

5.1.1 Licensee's Basis for Reauestino Relief The licensee stated "The system was not designed for exercise testing of these type of check valves. The safety function for these valves is to prevent drywell bypass leakage. These valves are located inside the drywell which is inaccessible during operation. The testing of these valves during normal operation would shut off essential cooling flow to the recirculation pump sealing water. These valves cannot be tested under present methods."

5.1.2 Alternative Testino The licensee proposed "Because the valves cannot be exercised or leak rate tested in the present system configuration, as an interim, the check valves will require non-destructive examination to be performed to verify position.

This type of examination was performed acceptably during RF-4. In addition, a modification request has been generated to add three vent valves to aid in the performance of leak rate testing to verify closure. This modification, when approved, should be installed during RF-5. The interim relief request will ,

then be rescinded upon completion of the modification." .

5.1.3 Evaluation The recirculation pump seals receive cooling water supply from the control rod drive hydraulic system. Two lines provide seal flow to the mechanical seals of the recirculation pumps which are located inside the drywell. The check valves listed in this relief request are the inner and outer drywell isolation check valves on each line. The Code requires that these valves be tested to their safety position every three months to verify the functioning of the valve. Testing these valves for closure during power operations would interrupt the flow of seal water to the recirculation pump mechanical seals

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which could potentially damage the pump and therefore is impractical. Testing these valves at cold shutdowns would also be impractical if the recirculation pumps were in operation. Immediate imposition of the Code requirements would ,

be a burden on the licensee.

A review of Figure 5.4-2a in the River Bend USAR shows that these check valves cannot be tested individually for closure verification because there are no test taps between each pair of valves. The licensee has proposed to modify the seal water piping in order to conduct leak rate testing on the drywell isolation check valves by adding three vent valves to the system during the RF-5 refueling outage (the RF-4 refueling outage ended in June 1993). The licensee has also proposed to conduct radiography on each of the check valves to verify closure on a refueling outage frequency until the modification has been completed. According to the licensee, closure verification using radiography was conducted successfully on each of the four check valves during the RF-4 refueling outage.

The modification to the seal water piping proposed by the licensee should allow for individual leakage testing of the check valves to verify closure and therefore conform to the Code exercise procedure requirements. In the interim period, the licensee's proposal to use non-destructive testing techniques to verify closure of the check valves is recognized by the staff as an acceptable alternative to the Code requirements because it provides direct indication of check valve disk position and therefore provides a reasonable assurance of operational readiness.

The licensee stated in a teleconference on August 6, 1993, that after the modification to the recirculation pump seal water piping has been completed, testing should be possible at a quarterly frequency. However, if the licensee determines testing can only be conducted at refueling outages, a relief request should be submitted before the RF-5 refueling outage to allow the staff ample time to review the request. If testing can only be performed at a i cold shutdown frequency, a cold shutdown justification should be added to the licensee's IST program prior to the start of the RF-5 refueling outage.

5.1.4 Conclusion Interim relief is granted pursuant to 10 CFR 50.55a(a)(3)(1) based on the l licensee's proposed alternate method of testing in the interim period which will provide an acceptable level of quality and safety. Interimr'elief is granted until the modifications to the recirculation pump seal water supply lines can be completed in the RF-5 refueling outage which will enable testing )

in accordance with the Code requirements. j l

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6.0 CONCLUSION

4 The staff has determined that the alternative testing provisions provide an acceptable level of quality and safety pursuant to 10 CFR 50.55a(a)(3)(1).

The staff has also determined that the relief granted, pursuant to 10 CFR 50.55a(f)(6)(1) is authorized by law and will not endanger life or property or the common defense and security and is otherwise in the public -

interest giving due consideration to the burden upon the licensee that could  ;

result if the requirements were imposed on the facility.  ;

Principle Contributor: Joseph Colaccino e October 22, 1993 r

Date:

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