ML17263A453
| ML17263A453 | |
| Person / Time | |
|---|---|
| Site: | Ginna  |
| Issue date: | 11/04/1993 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML17263A452 | List: |
| References | |
| NUDOCS 9311120060 | |
| Download: ML17263A453 (8) | |
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001
'nclosure SAFETY EVALUATION BY THE OFFICE OF NUCL AR REACTOR REGULATION RELATED TO THE INSERVICE TESTING PROGRAM RELIEF RE UESTS ROCHESTER GAS AND ELECTRIC CORPORATION R.E.
GINNA NUCLEAR POWER PLANT
- 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 requested by the licensee and alternatives authorized or relief 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,"
provided alternatives to the Code requirements determined acceptable to the staff.
Section 50.55a authorizes the Commission to grant relief from ASME Code requirements upon making the necessary findings.
The NRC staff's findings with respect to granting or not granting the relief requested as part of the licensee's IST program are contained in this Safety Evaluation (SE).
2.0 BACKGROUND
In Rochester Gas and Electric Corporation's April 23, 1992, submittal, nineteen anomalies identified in NRC s April 15,
- 1991, SE were addressed.
In a letter dated September 23, 1992, relief requests (RR)
PR-7 and VR-17 were withdrawn and a new RR PR-12, submitted for the service water pump flow measurement instrumentation.
The licensee's letter dated April 26, 1993, contained:
(1) new relief request VR-30, (2) a revision to PR-12, and (3) the proposed resolution to three remaining anomalies from the NRC's October 20,
- 1992, SE.
Evaluations of the new and revised RR are provided below.
The Ginna IST program addressed in this evaluation covers the third ten-year interval from January 1,
- 1990, through December 31,
- 1999, and was developed in accordance with the 1986 Edition of ASME Section XI, which was incorporated by reference in 10 CFR 50.55a(b)
(see 53 Federa1
~Re ister 16051, dated Ray 5, 1988).
9311120060 931104 PDR ADOCK 05000244 P
- 3. 0 EVALUATION The April 23, 1993 submittal contained one new relief request to perform stroke-time testing of auxiliary feedwater flow control valves during refueling shutdowns:
Additionally, RR PR-12 was revised to reflect the proper requirements for the containment recirculation fan cooler inlet and outlet valves.
These RR are evaluated below.
3.1 Relief Re uest VR-30 Relief from the requirements to quarterly stroke-time power operated valves
- 4297, 4298,
- 4480, and 4481 per IWV-3413 and evaluate the stroke-times per IWV-3417 is requested.
Valves 4297 and 4298 control auxiliary feedwater flow from the turbine-driven auxiliary feedwater pump to the steam generators.
These valves perform a safety function to open, and they are normally open during power operation.
Valves 4480 and 4481 are bypass flow control valves from the motor-driven auxiliary feedwater pumps which are used during startup to provide better flow control to the steam generators.
Their safety function is to remain closed upon receipt of a safety injection signal.
3.1.1 Licensee's Basis For Relief The licensee states:
"These valves are hand control valves which operate using a vari able set air signal.
They do not have a typical control switch.
Position indication is not directly indicated, only the control air signal is indicated.
Manual activation of these valves is not possible in the present configuration.
Lifting of leads or jumpers for the valve controls would be necessary.
Stroke timing during power operation would require rendering these valves inoperable and entering a Limited Condition for Operation (LCO).
Valves 4297 and 4298 perform their safety function by opening, are normally open and fail open.
Valves 4480 and 4481 perform their safety function by
- closing, are normally closed and fail closed."
- 3. 1.2 Alternative Testin The licensee proposes:
"Measurement and evaluation of stroke times shall be performed during refueling shutdowns.
These valves will be exercised and fail-safe tested quarterly."
3.1.3 Evaluation Paragraph IWV-3413(b) of ASME Code Section XI requires that "the stroke ti'me of all power-operated valves shall be measured... whenever such a valve is full stroke tested."
Control valves are not typically designed to have position indication and performing stroke time measurement by the conventional method using position indication lights is often impractical, such as for the subject valves.
Control valves
- 4297, 4298,
- 4480, and 4481 have a fail-safe function and do not have a typical control switch that allows an operator to directly stroke the valves.
No position indicating lights are provided that would allow stroke-time measurement.
Testing during power operation is impractical because it would require lifting of leads or jumpers for the valve controls in order to measure stroke time "from the initiation of the actuation signal to the end of the actuation cycle,"
as required by IWV-3413.
This action would render the valves inoperable and place the licensee in an LCO per their Technical Specifications, which could create a safety concern if these valves were required to perform their safety function, based on the time for restoration of the control leads.
Therefore, testing these valves during power operation is not practical.
However, in order to defer stroke-time testing to refueling
- outages, the testing must also be impractical during cold shutdowns (s/d).
This issue is not addressed in the RR.
Based on a phone conversation with the licensee on June 22, 1993, stroke-time testing can be performed during cold s/d because these valves are not required to be operable with the plant at cold s/d conditions.
Therefore, this RR should be changed to a cold s/d justification.
IWV-3412 allows that valves that cannot be tested during plant operation may be tested during cold shutdowns.
These valves should continue to be exercised and fail-safe tested on a
quarterly basis to verify operational readiness and stroke-timed during cold s/d conditions.
- 3. 1.4 Conclusion This RR is denied based on the fact that testing can be performed during cold shutdowns.
The licensee should delete RR VR-30 and write a cold shutdown justification for the stroke-time testing of these valves.
Deferring testing to cold s/d does not require approval by the NRC as it is in accordance with the Code.
The basis for deferring testing is subject to'NRC inspection (reference guestion 102 of the "Minutes of the Publi,c Meetings on Generic Letter 89-04" dated October 25, 1989).
3.2 Relief Re uest PR-12 Relief Request PR-12 was submitted by the licensee by letter dated September 23,
- 1992, and was approved by the staff in an SE issued on October 20, 1992.
This RR stated that twelve manual butterfly valves serving the inlets and outlets to the four containment recirculation fan coolers (valves
- 4627, 4628,
- 4629, 4630,
- 4635, 4636,
- 4641, 4642,
- 4643, 4644,
- 4757, and 4758) would be reclassified from Category A-Active to Category A-Passive.
The licensee is revising the classification of these valves as follows:
"Cooler Outlets (4629,
- 4630, 4636,
- 4643, 4644, and 4758) are Category A-Passive and require a valve leak rate test in accordance with ASNE, E
Section XI, IWV-3420 each refueling shutdown.
No position indication test is required since these valves do not have remote position indication."
- and, "Cooler Inlets (4627,
- 4628, 4635, 4641,4642, and 4757) are no longer required to be in the IST Program.
These valves presently have a requirement for quarterly stroke testing.
- However, since these valve's only safety function is to remain open, RG&E has imposed administrative limits to maintain these valves locked-open.
Hased on this change, there are no IST requirements for the valves."
These changes essentially reduce the scope of the RR by eliminating IST
'equirements for the cooler inlet valves and, therefore, do not change the basis for RR PR-12.
Therefore, PR-12 does not need to be re-evaluated and remains acceptable as previously approved.
- 4. 0 RESOLUTION OF ANOMALIES The licensee submitted proposed resolutions to anomalies identified concerning RR PR-10, VR-7, and VR-18.
Each of these is discussed below.
- 4. 1 Relief Re uest PR-10 Relief Request PR-10, which requested an alternative to allow measurement of discharge pressure of the diesel generator fuel oil transfer pumps rather than inlet and differential pressure, was authorized in the October 20,
- 1992, SE.
- However, a note in the evaluation stated the following: "Though the relief request is written as if the licensee intends to continue to measure differential pressure, the cover letter for the relief request indicated that they did intend to measure discharge pressure in lieu of differential pressure."
Cl The licensee has submitted a revised RR to reflect that differential pressure will not be measured.
The licensee has addressed the concerns of the anomaly.
No further action is required.
4.2 Relief Re uest VR-7 In Relief Request VR-7, the licensee requested relief from the remote position indication verification requirements of Section XI for the pressurizer relief
- valves, and proposed to verify valve remote position indication during reactor refueling outages by simulating valve actuation by moving the valve's coil.
Relief was granted provided the valve position indication is verified to accurately reflect obturator position.
In the October 20,
- 1992, SE, the staff identified a concern related to ensuring that the interface between the position indication and the pressurizer safety valves is verified; that is, verification of the position of the valve stem/disk is represented by the position indication at the valve.
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The licensee stated that following completion of the calibration of the position indication, the position indicators are mounted on the safety valves and "the proper clearance is obtained to ensure obturator motion will be accurately represented.
This is a mechanical interface and the fitup tolerances are monitored to ensure proper operation."
These procedural controls employed for the verification of the position indication are adequate to provide sufficient assurance that the indication accurately reflects obturator position.
The licensee has addressed the concerns of the anomaly.
No further action is required.
4.3 Relief Re uest VR-18 The licensee has requested relief from the stroke-time measurement requirements of Section XI, IWV-3413 and IWV-3417, for valves
- 5907, 5907A,
- 5908, and 5908A, the solenoid control valves that direct diesel fuel oil flow either to the day tanks or back to the diesel oil storage tanks.
The licensee proposed to verify proper valve operability by observing their operation during quarterly diesel testing, but stroke times will not be measured.
4.3. 1 Licensee's Basis For Relief These are rapid-acting solenoid valves whose design prohibits visual observation of stroking as there are no external indicators on these valves.
These valves are automatically actuated as necessary based upon diesel oil day tank levels.
These valves do not have control switches.
Diesel generators are tested monthly (per Technical Specifications),
during which these valves actuate for filling the day tanks and for diesel oil recirculation.
No history of diesel generator testing failure has been attributed to performance of these valves.
4.3.2 Alternative Testin Heasurement and evaluation of stroke time shall not be performed.
These valves shall be exercised and fail-safe tested at least quarterly during diesel generator testing.
Valve stroking parameters will be considered acceptable based upon satisfactory actuation as demonstrated by adequate fuel flow during testing.
4.3.3 Evaluation Relief Request VR-18 requested relief from the stroke-time measurement requirements of Section XI, IWV-3413 and -3417, for valves
- 5907, 5907A,
- 5908, and 5908A, the solenoid operated valves (SOVs) that direct diesel fuel oil flow either to the day tanks or back to the diesel oil storage tanks.
Relief was requested from stroke-time measurement since these valves are totally enclosed and have no visible indication of valve position.
The licensee proposed that the monthly diesel generator operational tests and quarterly fail-safe test of the valves ensure that these valves are operating properly.
In the October 20,
- 1992, SE, the staff stated that while the monthly testing verifies that these valves operate, the testing provides no information relative to degrading conditions of the valves'he staff also recommended that if the licensee could not determine an acceptable test to verify degradation, an enhanced preventive maintenance schedule could be an acceptable alternative.
The licensee evaluated the feasibility of performing enhanced preventive maintenance by evaluating the failure history of these valves and similar model SOVs within the industry.
There was no history of failures at Ginna and only four failures documented over a 20-year period in the licensee's Nuclear Plant Reliability Data System.
The licensee determined as a result of this search that these valves do not justify performance of enhanced preventative maintenance based on the service conditions and failure history There are two alternatives available for the licensee to obtain meaningful stroke times for these valves:
(1) replace these valves with valves having position indication, or (2) develop some other means of determining valve
- position, such as non-intrusive diagnostic test methods'ither of these alternatives would be burdensome to the licensee based on the limited number of valves, the number of past failures, and the amount of equipment necessary to perform this testing.
In addition, an analysis was performed by the licensee demonstrating that alarms exist that would provide operators adequate time (in excess of 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />) to mitigate any adverse effects in the event of SOV failure.
Each of the options mentioned would result in hardship or unusual difficulty for the licensee, and since the effects of a failure can be mitigated successfully, these options are not justified 4.3.4 Conclusion The proposed alternative to the Code requirements is authorized pursuant to 10 CFR 50.55a(a)(3)(ii) based on the determination that compliance with the specified requirements results in hardship or unusual difficulty without a
compensating increase in the level of quality and safety Principal Contributors:
CD Orsini DE Fischer PE Campbell Dated:
November 4,
1993
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