ML17158A307

Safety Evaluation Accepting Deferral of Valve Exercising from Quarterly,Or During Cold Shutdowns,To Refueling Outages

ML17158A307
Person / Time
Site:	Susquehanna
Issue date:	05/23/1994
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML17158A306	List: ML17158A305 ML17158A307
References
GL-89-04, GL-89-4, IEB-93-003, IEB-93-3, NUDOCS 9406030057
Download: ML17158A307 (4)

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UNITED STATES NUCLEAR REGULATORY COMMISSION ENCLOSURE WASHINGTON, D.C. 2055&0001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO THE INSERVICE TESTING PROGRAM RE UESTS FOR RELIEF PENNSYLVANIA POWER

& LIGHT COMPANY SUS UEHANNA STEAM ELECTRIC STATION UNITS 1

AND 2 DOCKET NUMBERS 50-387 50-388

1.0 INTRODUCTION

The Code of Federal Regulations, 10 CFR 50.55a, requires that inservice testing (IST) of certain ASHE Code Class 1, 2; and 3 pumps and valves be performed in accordance with Section XI of the ASHE Boiler and Pressure Vessel 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)(i), (a)(3)(ii), or (f)(6)(i) of 10 CFR 50.55a.

In proposing alternatives or requesting relief, the licensee must demonstrate that:

(1) the proposed alternatives provide an acceptable level of quality and safety; (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.

NRC guidance contained in Generic Letter (GL) 89-04, "Guidance on Developing Acceptable Inservice Testing Programs,"

provides alternatives to the Code requirements determined acceptable to the staff without further NRC review.

Implementation of the GL 89-04 positions is subject to inspection.

Section 50.55a of 10 CFR Part. 50 authorizes the Commission to approve alternatives and to grant relief from ASHE Code requirements upon making the necessary findings.

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).

Furthermore, in rulemaking to 10 CFR 50.55a effective September 8,

1992, (see 57 Federal Re ister 34666),

the 1989 edition of ASHE Section XI was incorporated in 10 CFR 50.55a(b).

The 1989 edition provides that the rules for IST of pumps and valves shall meet the requirements set forth in ASHE Operations and Maintenance Standards Part 6 (OH-6),

" Inservice Testing of Pumps in Light-Water Reactor Power Plants,"

and Part 10 (OM-10), "Inservice Testing of Valves in Light-Mater 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.

Because the alternatives meet later editions of the Code, 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 requirements are met is subject to NRC inspection.

In their letter dated October 12,

1993, Pennsylvania Power

& Light Company submitted Revision 9 (Unit 1) and Revision 6 (Unit 2) of the Susquehanna Steam 940sosoo57 9oosR PDR ADDCK 05000387 P

PDR

Electric Station Inservice Testing Program Plans for Pumps and Valve Operational Testing.

These revisions corrected the numbering of valves in the control rod drive system and added the valves associated with the reactor water level backfill modifications to address NRC Bulletin 93-03, "Resolution of Issues Related to Reactor Vessel Mater Level Instrumentation in BWRs."

Relief Request 69 (each unit) for extension of the testing frequency for these valves was included and is evaluated below.

2.0 EVALUATION OF RELIEF RE VEST 69 EACH UNIT NRC Bulletin 93-03 required boiling-water reactor licensees, with the exception of Millstone, Unit 1, and Big Rock Point, to make hardware modifications to ensure the reactor vessel level instrumentation system design is of high functional reliability for long-term operation.

To address the bulletin, Pennsylvania Power

& Light (PP&L) Company added the following valves to the nuclear boiler vessel instrumentation system to the Susquehanna Steam Electric Station, Units 1 and 2, inservice testing program.

Unit 1:

142032, 142044,

142059, 142071,

142033, 142045,

142060, 142072 Unit 2:

242032, 242044,

242059, 242071,

242033, 242045,

242060, 242072 The safety function of these valves is to prevent reverse flow out through the backfill lines of the vessel level instrumentation from the control rod drive hydraulic system.

The valves have been categorized as "Category A,"

indicating that they have a seat leakage criteria.

The valve table indicates that the applicable tests are "CV" and "LT" for check valve closure verification and leak-tightness.

The Code class is designated as "Non-Code Safety Function," indicating that these valves are outside the scope of 10 CFR 50.55a, but are included in the inservice testing program as supplemental, or augmented, components.

PP&L has requested relief from the requirements of ASME Code,Section XI, IWV-3521, for exercising the valves to their closed positions once per 92 days.

2. 1 PP&L's Basis for Relief The licensee states:

These check valves, located in backfill lines for the reactor water level instrumentation, provide Control Rod Drive Hydraulic System water flow into their respective instrument line reference legs, while preventing flow of instrument line water inventory in the reverse direction.

To support the continued integrity of the reactor water level instrumentation during accident conditions, these check valves have been assigned a very small reverse flow leakage limit (0.5 ibm/hr) by PP&L.

These check valves have been designed for 'periodic removal from their system and bench testing of their reverse flow leakage, to facilitate the demonstration that they meet their unusually small leakage limit.

Removal of these check valves from the system for exercise testing and leakage testing on a test bench is not practical

during periods of plant operation nor during periods of plant cold shutdown because their isolation for removal and testing causes loss of some reactor water level indication in the control room and creates the potential for actuation of Engineered Safety Features (ESFs) associated with each of the instrument lines being isolated.

Loss of control room indication of reactor water level on some instruments is acceptable and prevention of unplanned ESF actuation is possible only during refueling outages.

Further, removal, testing, and reinstallation of the check valves produces a risk of introducing air into the reference leg piping.

As the purpose of this equipment is prevention of gas entrainment in the reference leg piping, removal, testing, and reinstallation of the check valves may be attempted only during refueling outages.

2.2 Pro osed Alternative Testin PP&L proposes:

Demonstrate closure of each check valve in the reactor water level instrumentation backfill lines and demonstrate reverse flow leakage of each check valve less than its limit once per refueling outage.

2.3 Evaluation The regulations do not require that the staff approve relief requests for augmented testing of non-Code components included in the inservice testing program.

Generic Letter 89-04, Position 11, alerted licensees that there were components outside the scope of 10 CFR 50.55a which are safety-related and require testing at some frequency to meet requirements specified in 10 CFR 50, Appendix A and Appendix B.

Position 11 further indicated that it was acceptable to the staff for licensees to include such components in the inservice testing program.

However, even if the subject valves were Code class components, the extension of the test interval from quarterly to each refueling outage would be acceptable in accordance with the latest approved rules for inservice testing.

In rulemaking to 10 CFR 50.55a effective September 8,

1992, (See 57 Federal

~Re ister 34666),

the 1989 edition of ASNE Section XI was incorporated in Paragraph (b) of 10 CFR 50.55a.

The 1989 edition provides that the rules for IST of valves shall meet the requirements set forth in ON-10.

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.

Therefore, relief is not required for those inservice tests that are conducted in accordance with ON-10, or portions

thereof, Whether all related requirements are met is subject to NRC inspection.

Paragraph 4.3,

" Inservice Tests for Category C Valves," of ON-10, gives the rules for inservice testing of check valves in accordance with the 1989 Edition of ASNE Section XI.

In the exercising requirements of this paragraph it states that check valves shall be exercised or examined in a manner which

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verified obturator travel to the position required to fulfill its function quarterly, but provides for conditions where quarterly exercising is impractical.

It also provides that valves which cannot be exercised during cold shutdowns may be full-stroke exercised during refueling outages.

PPEL has described the conditions which make exercising quarterly during power operations or during cold shutdown conditions impractical and has proposed to exercise the valves during refueling outages, consistent with the requirements of OM-10.

All the requirements of OM-10, Paragraph 4.3.2.2, must be met including subparagraph (h) which requires that all valve testing required to be performed during a refueling outage shall be completed prior to returning the plant to operation.

The requirements of Paragraph 6.2, "Test Plans," of OH-10, to maintain a record of the justification for deferral of stroke testing in accordance with Paragraph 4.2.3.3 are met by documenting the deferred testing in Relief Request 69.

The staff finds the deferral of valve exercising from quarterly, or during cold shutdowns, to refueling outages, acceptable because the proposed test frequency is in accordance with the requirements of OH-10, as discussed above.

3. 0 CONCLUSION The staff concludes that the alternate testing described will provide reasonable assurance of the operational readiness of the subject valves to perform their safety-related function.

The staff has determined that approving the alternative, pursuant to 10 CFR 50.55a(a)(3) is not required because the-check valves are not ASME Code Class 1, 2, or 3, notwithstanding that the testing is considered augmented to the scope of 10 CFR 50.55a.

Principal Contributor:

P.

Campbell Date:

May 23, 1994