ML20127D136
| ML20127D136 | |
| Person / Time | |
|---|---|
| Site: | Waterford  |
| Issue date: | 01/11/1993 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20127D103 | List: |
| References | |
| NUDOCS 9301150106 | |
| Download: ML20127D136 (4) | |
Text
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UNITED STATES
.f g r NUCLEAR REGULATORY COMMISSION
- $g-W ASHING TON. D. C. 20555
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y, SAFETY EVAlVXION BY THE OFFICE OF NUCLEAR REACTOR REGULATION Rf1ATED TO THE 1PSIRY_lCE TESTING PROGRAM RE0 VEST FOR RELIEF ENTERGY OPERATIONS. INC.
FATERFORD 3JTEAM AND_LLICTRIC STATION DOCKET N0m 50-382
1.0 INTRODUCTION
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 granted or proposed alternatives have been authorized by the Commission pursuant to 10 CFR 50.55a(f)(6)(i), (a)(3)(i), or (a)(3)(ii).
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.
10 CFR 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 paragraph (b) of Section 50.55a, subject to the limitations and modifications listed, and subject to Commission approval.
NRC guidance contained in Generic Letter (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 follew the guidance delineated in the 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. Additionally, Paragraph (f)(4)(iv) of Section 50.55a allows the staff to approve the use of later editions and addenda, or portions thereof if all related requirements are met.
Approval under Paragraph (f)(4)(iv) does not require granting relief from Code requirements, as the requirements of the later edition are imposed.
The findings of the staff are contained in this safety evaluation (SE).
This SE concerns a relief request and supporting information that was submitted by Entergy Operations, Inc. (Entergy) in a letter dated November 17, 1992, for the Waterford 3 IST Program.
The results of this review are provided below.
The Waterford 3 IST Program was developed to be consistent 9301150106 930111 PDR ADOCK 05000382 P
f t with the ASHE Boiler and Pressure Vessel Code Section XI, 1980 Edition, Winter 1981 Addenda.
2.0 REllEF RE0 VEST The licensee has requested relief from the requirement of IWV-3521 that check valves, specifically the high pressure safety injection (HPSI) pump discharge check valves (SI-207A, S1-2078, and SI-207AB), be exercised at least once every 3 months, except as provided by IWV-3522.
IWV 3522(a) requires that
" Valves... whose function is to prevent reverse flow shall be tested in a manner that proves that the disk travels to the seat promptly on cessation or reversal of flow."
2,1 Licensee's Basis for Relief The licensee states:
These valves perform a safety function in both the open and closed positions.
As previously discussed in the Basis for Relief for Relief Request 3.1.14, the operability testing (full-stroke) of these check valves' open safety function can only be accomplished by directing full HPSI pump flow into the RCS [ reactor coolant system). No other flow path exists which could achieve the required HPSI pump flow rate. These valves cannot be full-stroke exercised during power operation because the HPSI pumps cannot overcome RCS pressure to provide flow into the RCS.
Partial stroke exercising at power is possible through a flow path to the RWSP [ refueling water storage pool] through a drain valve.
However, the capacity of this flow path is insufficient to full stroke the subject check valves.
During cold shutdown, the RCS is on shutdown cooling (SDC).
Pressurizing the SDC system with full HPSI flow increases the possibility of low temperature overpressure concerns.
Therefore, the required flow can only be achieved during refueling outages, when the Reactor Vessel head is removed.
Since these valves can only be exercised to the full open position during each refueling outage, the requirement to verify that the disk travel to the seat from the open position can only be performed during each refueling outage.
2.2 Alternative Testina The licensee proposes:
These valves will be part-stroke exercised open and then verified to close quarterly.
These valves will be full-stroke exercised and t'<
verified to close during each refueling outage.
1 i
e
2.3 Evaluation This evaluation is divided into two parts in order to discuss the opening capability of the valves and the closure capability separately.
2.3.1 Reouirement to full-stroke exercJse open the valves cuarteriv:
In rulemaki.ng to 10 CFR 50.55a effective September 8, 1992 (See 57 Federal Reaister 34666), the 1989 Edition of ASME Section XI was incorporated in paragraph (b) of Section 50.55a.
The 1989 Edition provides that the rules for inservice testing of valves are as s)ecified in OM-10.
The staff imposed a modification to OM-10 associated wit 1 containment isolation valves leakage testing as discussed in 10 CFR 50.55a(b)(2)(iv).
10 CFR 50.55a(f)(4)(iv) provides that inservice tests of valves may meet the requiremants set forth in subsequent editions and addenda that are incorporated by reference in paragraph (b) of Section 50.55a, subject to the 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, Paragraph 4.3.2.2 (b) states the following:
If full-stroke exercising during plant operation is not practical it may.
be limited to part-stroke during plant operation and full-stroke during cold shutdowns.
OM-10, Paragraph 4.3.2.2 (e) states the following:
If exercising is not practicable during plant operation or cold shutdowns, it may be limited to full-stroke during refueling outages.
The licensee has described in the relief request that full-stroke exercising these check valves to the open position can only be accomplished by directing full HPSI pump flow into the RCS (and that no other flow path exists which could achieve the required flow rate through the check valves).
These valves cannot be full-stroke exercised open during power operation because the HPSI pumps cannot overcome RCS pressure to provide flow into the RCS.
Furthermore, pressurizing the shutdown cooling (SDC) system with HPSI flow during cold shutdown is prohibited since this would increase the possibility of overpressurizing the RCS at low temperatures and should not be done.
Alternatively, the licensee proposes to part-stroke exercised open and then verify that these valves close quarterly. The proposed alternative testing is in accordance with OM-10 requirements for deferring testing from quarterly, or cold shutdowns, to refueling outages.
l Accordingly, the relief requested by the licensee, related to the frequency of full-stroke exercising of the high pressure safety injection pump discharge check valves to the open position, is covered by the rulemaking effective September 8, 1992.
The staff approves the use of this portion of OM-10, and, l
therefore, pursuant to 10 CFR 50.55a(f)(4)(iv), the impicmentation of the
F
.- proposed alternative is acceptable, and no further action is required, provided the licensee implement all related requirements such as OM-10, Paragraph 4.3.2.2 (h), which indicates that "all valve testing required to be performed during a refueling outage shall be completed prior to returning the plant to power."
Implementation is subject to NRC inspection.
2.3 2 Rtquirement (p_ exercise the valves to the closed _ position ouarterly:
It is generally not feasible or practical to verify that a check valve disk travels promptly to the seat.
Therefore, the staff has found reverse flow closure testing to be acceptable if it verifies the disk is in the closed position, irrespective of the valve closure timing.
That is, closure verification can be performed following either a part-stroke or a full-stroke exercise.
This position is further discussed in Question 24 of the meeting minutes for Generic Letter 89-04, Guidance on Developing Acceptable Inservice Testing Programs, Attachment 1, Position 3 (reference NRC letter to all 1icensees dated ocLober 25, 1989, Minutes of the Public Meetings on Generic Letter 89-04.
lWV-3522 requires that check valves be exercised [every 3 months] to the position required to fulfill their function, in this case the closed position, unless such operation is not practical during plant operation.
IWV-3522 paragraph states, in part:
Valves that are normally open during plant operation and whose function is to prevent reversed flow shall be tested in a manner that proves that the disk travels to the seat promptly on cessation or reversal of flow.
The licensee has indicated that the valve will be part-stroke exercised and then verified to close quarterly, and is verified to close following full-stroke exercising during refueling outages.
Therefore, the test frequency (quarterly) for closure verification is in accordance with Section XI and relief is not required.
3.0 CONCLUSION
in evaluating the licensee's request for relief from the requirements of Section XI, the staff has determined that the licensee's proposal complies with the requirements of a later edition of the Code, specifically the 1989 Edition of Section XI, which has been incorporated in 10 CFR 50.55a(b).
Further, the staff has determined that approval to use the applicable portion of the later edition is acceptable, and this SE provides the approval pursuant to 10 CFR 50.55a(f)(4)(iv).
Principal Contributor:
David C. Fischer Date: Janauary 11, 1993
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