ML17158B119
| ML17158B119 | |
| Person / Time | |
|---|---|
| Site: | Susquehanna  |
| Issue date: | 02/23/1996 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML17158B118 | List: |
| References | |
| NUDOCS 9602270368 | |
| Download: ML17158B119 (7) | |
Text
I ~RECc tl UNITED STATES I
o NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 2055&0001 Cy SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO INSERVICE TESTING PROGRA RE UESTS FOR RELIEF PENNSYLVANIA POW R AND LIGHT COMPANY SUS UEHANNA STEAM ELECTR C STATION UNITS 1
AND 2 DOCKET NUMBER 50-387 AND 50-388
- 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 American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME 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(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.
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 (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 specified in Positions 1, 2, 6, 7, 9, and 10 provided the licensee follows 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.
By letter dated May 30,
- 1995, Pennsylvania Power and Light Company (PP&L), the
'licensee for the Susquehanna Steam Electric Station Units 1 and 2, submitted a
revision to the Inservice Inspection Program for Pump and Valve Operational Testing.
The revision added three Fuel Pool Cooling manual valves to the licensee's IST program in accordance with the ASME Code.
In Refueling Outage Test Justification No.
21 (ROJ-21),
the licensee proposed exercising each of these valves at least once during each refueling period.
The revision also 9602270368 960223 PDR ADOCK 05000387 8
made an administrative change to the licensee's basis for relief for Relief Request No. 15.
The latter change is editorial in nature and does not impact the staff's previous authorization of alternative testing.
By letter dated August 4, 1995, the licensee submitted a revision to ROJ-20 eliminating those valves which are practical to test during power operation.
The licensee submitted Relief Request No.
23 in order to defer the testing of those valves removed from ROJ-20 to an 18-month frequency.
The current 10-year interval for the Susquehanna Steam Electric Station Units 1
and 2 began June 1,
1994.
The current IST program is based on the requirements of the 1989 Edition of the ASIDE Section XI Boiler and Pressure Vessel Code (the Code) in accordance with 10 CFR 50.55a.
Section 50.55a authorizes the Commission to grant relief from ASNE 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).
2.0 REFUELING OUTAGE TEST JUSTIFICATION NO.
2 ROJ-21 Three Fuel Pool Cooling manual valves for each unit were added to this refueling outage justification to allow testing of the manual valves in the Fuel Pool Cooling System flow path every refueling outage instead of every 92 days.
The specific valves being added to ROJ-21 are:
Unit 1
- 153001, 153018A, and 153018B Unit 2
- 253001, 253018A, and 253018B
- 2. 1 Evaluation
- 2. 1, 1
Background
In a letter dated August 8, 1994, the licensee committed to include the Residual Heat Removal (RHR) Fuel Pool Cooling manual valves in its IST program.
This commitment
- stemmed, in part, from concerns documented in NRC Inspection Report No. 94-12 involving the lack of testing of certain Fuel Pool Cooling manual valves.
The Inspection Report discussed the need for a testing program that assures the operational readiness of safety-related manual valves, particularly those valves that must change position to perform their safety function.
The original version of ROJ-21 was submitted by letter dated December 29, 1994, in response to that commitment.
Because the NRC is not required to approve refueling outage justifications, the staff did not formally review ROJ-21 at that time.
- 2. 1.2 Code Requirements The licensee's current 10-year interval is based on the 1989 Edition of the ASIDE Code (i.e.,
OM-10 for valves) which allows the licensee to defer testing beyond quarterly intervals if such testing is impractical.
The requirements of OM-10 have been accepted by the staff, provided all related requirements set forth in OH-10 are met and the licensee provides adequate justification that the testing of a particular valve is impractical at any time other than during the refueling outage.
NUREG-1482, "Guidelines for Inservice Testing at Nuclear Power Plants,"
provides guidance regarding the determination and acceptability of impracticality as a basis for deferring valve testing to refueling outages.
Section 2.4.5 of NUREG-1482 states:
Impractical conditions justifying test deferrals are those that could result in an unnecessary plant shutdown, cause unnecessary challenges to safety systems, place undue stress on components, cause unnecessary cycling of equipment, or unnecessarily reduce the life expectancy of the plant systems and components.
The licensee states that the present requirement of exercising these valves once each 92 days will result in hardship without a compensating increase in the level of quality and safety.
The hardships associated with testing these manual valves every 92 days include system depressurization, unnecessary system filling and venti.ng, and system operation in restricted flow configurations which apparently could cause excessive wear or damage to equipment.
Hardships, such as these, help provide the staff with a basis for approving an alternate to the Code testing requirements (i.e., pursuant to 10 CFR 50.55a(a)(3)(ii)).
- 2. 1.3 Discussion By letter dated Hay 30,
- 1995, the licensee added several manual valves to ROJ-21.
It appears that it may be impractical to stroke some of the valves discussed in ROJ-21 (i.e., either quarterly or during cold shutdown)
- and, therefore, a
ROJ is appropriate.
However, exercising some of these valves quarterly or during cold shutdown might not involve conditions that meet the guidance for determining impracticality set forth in NUREG-1482, which are discussed above.
Accordingly, it may be practical to exercise (i.e., either quarterly or during cold shutdown conditions) these valves within the scope of ROJ-21.
The licensee must obtain authorization from the NRC pursuant to 10 CFR 50.55a(a)(3)(ii) to defer testing for those valves that can be exercised quarterly or during cold shutdown conditions.
The basis for the test deferral, while described briefly in the
- ROJ, needs to be more fully developed, The hardships of testing needs to be discussed as well as the basis for the licensee's assertion that there would be no compensating increase in the level of quality and safety by imposing quarterly testing as specified in the Code.
2.2 Conclusion The licensee should review and revise ROJ-21 to ensure that it contains only manual valves that are impractical to test in accordance with the ASHE Code.
Other manual valves should be tested in accordance with the Code or the licensee should request that an alternative to the Code testing requirements be authorized by the NRC.
In this instance, the licensee may wish to document the hardship associated with testing these valves quarterly and during cold shutdown conditions and explain why testing these valves once each refueling outage does not adversely impact the level of quality and safety.
The licensee is also encouraged to work with the ASIDE to define appropriate testing requirements for manual valves.
3.0 RELIEF RE UEST NO.
23 RR-23 By letter dated April 26,
- 1995, the staff identified the need for additional information regarding the ROJ-20 for the excess flow check valves (EFCVs) in PP&L's IST program.
This request for additional information (RAI) was prompted by an EFCV test conducted at power on Unit 1.
The licensee revised ROJ-20 to clarify the impracticality of performing quarterly full-stroke testing for the EFCVs and submitted RR-23 in order to obtain authorization for; f
q f
h EFCV h t at power.
- 3. 1 Licensee's Basis for Requesting Relief The licensee states the following in support of RR-23:
Excess flow check valves are installed on instrument lines penetrating containment in accordance with Regulatory Guide
- 1. 11.
As such, the lines are sized and/or orificed such that off-site doses will be substantially below 10 CFR Part 100 limits in the event of a rupture.
Therefore, individual leak rate testing of these valves is not required for conformance with 10 CFR Part 50, Appendix J requirements.
Functional testing of valves to verify closure can be accomplished by the process of venting the instrument side of the valve while the process side is under pressure.
Such testing is required by Technical Specification 4.6.3.4 at least once per 18 months.
Testing on a more frequent basis is im ractical for several reasons.
The testing described above requires the removal of the associated instrument or instruments from service.
"Since these instruments are in use during plant operation, removal of any of these instruments from service may cause a spurious signal which could result in a plant trip or an unnecessary challenge to safety systems.
Testing on a quarterly basis is deemed impractical since the risk of performing the test quarterly outweighs the benefit achieved with a quarterly test since the quarterly testing would reduce the plant's margin of safety.
3.2 Alternative Testing The licensee proposes:
Functional testing with verification that flow is checked will be performed at least once per. 18 months per Technical Specification 4.6.3.4.
3.3 Evaluation 3.3.1
Background
The staff documented its original review of ROJ-20 in a Safety Evaluation (SE) dated February 23, 1995.
This SE addressed the licensee's second 10-year inservice testing interval.
ROJ-20 was acceptable based on the licensee's determination that it was impractical to test the EFCVs during power operation.
On March 24,
- 1995, the NRC was notified of an event at Susquehanna which placed the plant in a 72-hour technical specification action statement to shutdown due to the inoperability of a jet pump EFCV.
This event prompted an RAI from the staff regarding why EFCVs were being tested during power operations.
The licensee's response to that RAI was to submit a revision to the current IST program deleting those valves for which it is ractical to test at power from ROJ-20.
The current submittal also includes RR-23 that proposes to defer the testing of certain EFCVs to an 18-month frequency.
3.3.2 Discussion The Code requires that check valves be exercised to the position required to fulfilltheir safety function every 3 months.
These valves have a safety function in the closed direction to isolate the associated instrument line in the event of a line failure outside of. containment.
The licensee indicated that functional testing of valves to verify closure can be accomplished by venting the instrument side of the valve while the process side is under pressure.
Such testing is required by Technical Specification 4.6.3.4 at least once per 18 months.
According to the licensee:
Testing on a more frequent basis is impractical for several reasons.
The testing described above requires the removal of the associated instrument or instruments from service.
Since the instruments are in use during plant operation, removal of any of these instruments from service may ca'use a spurious signal which could result in a plant trip or an unnecessary challenge to safety systems.
This rationale (i.e., impracticality) provides an adequate basis on which to defer Code-required testing from quarterly to a refueling outage frequency (i.e., during a refueling outage).
However, it does not provide, in and of
I' T
- itself, an adequate basis to conduct Code-required testing at power (i.e immediately before refueling outages) and does not address how testing these valves then provides an acceptable level of quality and safety.
The licensee merely states:
Testing on a quarterly basis is deemed impractical since the risk of performing the test quarterly outweighs the benefit achieved with a quarterly test since the quarterly testing would reduce the plant's margin of safety.
3.4 Conclusion The proposed alternative to the Code testing frequency is denied, in part because the licensee has not adequately justified why these valves should be tested at power immediately before refueling outages.
However, pursuant to 10 CFR 50.55a(f)(6)(i), the licensee is granted relief from the quarterly Code testing requirements for the subject EFCVs provided the licensee tests these valves during refueling outages
~
The staff concludes that testing the EFCVs during refueling outages 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. If the licensee seeks to test these EFCVs at power immediately before each refueling outage then a more detailed basis (e.g
~, maintenance history, risk analysis) for the proposed test interval should be provided (i.e., to demonstrate that the alternate provides an acceptable level of quality and safety)
~
4.0 CONCLUSION
S The staff has reviewed relief ROJ-21 submitted by PP&L and has determined that the licensee needs to revise this request to ensure that it contains only manual valves that are impractical to test in accordance with the ASNE Code Accordingly, this relief was not granted'n addition, relief RR-23 was also
- reviewed, and the staff determined that the proposed alternative to the Code testing frequency was not justified and that relief was denied, in part However, the staff granted relief from the quarterly Code testing requirements for the subject EFCVs provided the licensee tests these valves during refueling outages.
The staff concludes that testing the EFCVs during refueling outages 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 quarterly testing requirements were imposed on the facility Principal Contributors:
L. Dudes/D.
Fischer Date:
February 23, 1996