ML19254E733
| ML19254E733 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 10/15/1979 |
| From: | Wang A Office of Nuclear Reactor Regulation |
| To: | Cheng C Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 7911020261 | |
| Download: ML19254E733 (10) | |
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o UNITED STATES NUC1. EAR REGULATORY COMMISSION
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OCT 151979 5....
MEMORANDUM FOR:
C. Y. Cheng, Task Coordinator Engineering Branch Division of Operating Reactors FROM:
A. Wang Plant Systems Branch Division of Operating Reactors
SUBJECT:
NORTHEAST NUCLEAR ENET,GY COMPANY - INSERVICE VALVE TESTING PROGRAM AND RELIEF REQUEST (TAC 11210)
Plant Name: Millstone Nuclear Power Station, Unit i Occket Number: 50-245 Responsible Branch and Project Manager: ORB #2, J. Shea Review Branch: Reactor Safety Review Status: Complete The Plant Systems Branch has completed its review of th'e proposed inservice testing (IST) program for the non-ECC systems and the requests for relief submitted by Northeast Nuclear Energy Comoany for the Millstone Nuclear Power Station, Unit 1.
Our review included the evaluation of the licensees submittals of Feiaruary 28, 1977 and Feoruary 28, 1979, for compliance with the requirerents set fprth in Section XI of the 1974 ASME Boiler and Pressure Vessel Code and Su r:er of 1975 Addenda. We conci;de that the proposed IST program for tillistone Unit 1 i., acceptable. Our evaluation of the requests for relief from tne testing requirements is included in the enclosure.
'O u ar A. Wang Plant Systems Branch Division of Operating Reactors
Enclosure:
As stated cc:
D. Eisenhut E. Adensam B. Grimes G. Lainas P. Check G. Johnson D. Ziemann A. Wang J.SNa V. Nerses 1249 035 7911020 d b /
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. III. VALVE TESTING PROGRAM I'
A. General 1.
INTRODUCTION By letters dated February 28, 1977 and February 28, 1979, Northeast Nuclear Energy Company (NNECO) submitted propoced changes to the Millstone Unit 1 Technical Specifications to incorporate the provisions of 10 CFR 50.55(a) as revised on February 12,1979 (41 FR 6256). The Plant Systems Branch has reviewed the non-ECC Systems of the proposec test program.
Throughout our review, staff a,uestions regarding the adequacy of the program were directed toward the licensee.
Formal responses to these questions, together with corritments to modifications to the proposed test program were documented by the licensee in a revision to the plan.
To conduct our review we were provided boundary diagrars by the licensee.
3.
Subsection IWV 3410(a) of the Section XI Code (which discusses full stroke and partial stroke requirements) requires that Code Category A and B valves be exercised once every three months, with excections as defined in IWV-3410(b)(1), (e) cr.d (f).
Tii 3520(a) (which discusses full stroke and partial stroke reoui ements) requires that Code Category C valves be exercised once every tnree months, with excections as defined in IWV-3520(b).
In the above cases of excections, tra Coce permits the valves to be tested at cold shutdowm where:
(a)
It is not practical to exercise the valves to the position required to fulfill their function or to the partial position during cower coeratio~n.
(b)
It is not practical to observe the coeration of the valves (with fail-safe actuators) uoan loss " actuator pcwer.
TL staff stated its position to the licensee that check valves, wh0se safety function is to coen, are exoected to be full-stroked.
If only limited operation is possible (and it has been demonstrated by the licensee and agreed to by the staf#), the check vr.ive : hall be partial stroked. Since disk position is not always caservable, the NRC staff stated that verification of the plant's safety analysis design flow rate through the check valve would 'e an adequate D
de onstration of the full-stroke requiremer.t. Any flow rate less than design will be considered part-stroke exercising unless it can be shown that the check alve's disk position at the lower flow rate would be equivalent to or greater than that of the design flow rate through the valve. The licensee agreed to conduct his flow tests to satisfy the above position.
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- 2 5.J TP licensee has stated that none of the Category A or B power operated valves listed below can be part-stroked because of the design logic of the operating circuits.
These circuits are such that when an open or closed signal is received the valve must complete a full-stroke before the relay is released to allow the valve to stroke in the other direction. We find that the licensee relief request from part-stroking is warranted and should be granted because the required function of the valve involves only full open or full closed positions.
8.
The Appendix J review for this plant is a completely separate review from the IST program review. Howe ve r,
the determinations made by that review are directly applicable to the IST program. Our review has determined that the current IST program as submitted by the licensee correctly reflects our interpretstion of Section XI vis-a-vis Appendix J.
The licensee has agreed that, should the Appendix J program be amended, they will amend their IST program accordingly.
B.
Gene ral 1.
Relief Recuested The Category A valves will meet Appendix J leak testing requirements in lieu of Section XI requirements.
Code Recuirement t
Category A valves shall t'e leak tested to IWV-3420.
Basis for Recuesting Relief This aoplies to valves whose only safety function is containment isciation.
Present Tecn Specs require both an individual and an integrated leakage rate test for containment isolation valves and penetrations.
Tech Specs also require repair and retest of any valve exceeding the leakage criteria. NNECO feels that these tes" insure the leak-tightness of all containment isolation valves, in that they cre tested.. der the ccm:itions for which they are designed.
Operability testing of these valves during normal plant operation could cause a loss of containment integrity and/or system function if a valve failed in a nonconservative position.
NNECO also requests relief from paragrapn IWV-3420(f)
" Analysis of Leakage Rates" in that present rules for local leak rate testing of containment isolation i
valves provide analytical data for determining acceptance criteria, based on combined leakage of several valves.
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Based on seat leakage data rc.:or%. ta v 'e, in connection with the containment leak rate A_t progr.:, N.ECO request
.elief from paragraph IV"-3420(a)(2)
? that no meaningful trends tiave been established Evaluation The Category A valve leak rate test requirements of IWV-3420(a-e) have been superceded by Appendix J requirements for containment iLiation valves (CIV).
The NRC staff has concluded that the applicable leak test procedures and requirements for CIV's are detemined by 10 CFR 50 Appendix J.
Relief from paragraph IWV-3420(a-e) for CIV's presei. s no safety problem since the intent of IWV-3420(a-e) is met by the Appei. dix J requirements.
We agree with the licensee's basis that paragraphs f and g of IWV-3420 provide no additional infomation essential for plant operation or safety, or valve operability for Millstone 1 and the relief should be granted.
It should be noted this relief request applies only where a type C Appendix J 1eak test is performed.
Based on the consideration discussed above the staff concludes that the alternate testing proposed above will give the reasonable assurance of valve operability intended by the Code and that the relief thus granted
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will not endanger life or property or the common defense and security of the public.
C.
Condensate System 1.
Catecory C 1.1 Relief Recuested The licensee has proposed to exercise the following valves at pump rotations such that all valvos will be exercised at least once every six nonths:
a.
Condensate Pump 1A Discharge Valve I.CN-2A b.
Condensate Pucp 1B Discharge Valve 1-CN-25 c.
Condensate Pump 1C Discharge Valve 1-CN-2C d.
Condensate Booster Pump 1A 1-CN-30A Discharge Valve e.
Condensate Booster Pu p 1B i-CN-305 Discharge Valve f.
Conder. sate Booster Pume 1C 1-CN-30C Discharge Valve 1249 038
. Code Requirement Refer to caragraph III.A.3 Basis for Reauesting Relief These valves are in nomal service and are exercised as punos are routinely rotated.
Each individual valve will not t exercised every three months. Collectively, all valves will be exerciscd within a six month period.
Evaluation The valves listed in the above relief request are either passive and/or redundant valves. The optinum test interval for operability testing passive and/or redundant valves was d >',emined by the staff, using actual failure rate data and .,andard probabilistic techniques, to be in the range of three m ths to 27 months. The interval, which has been proposed as the exercise interval for the abcve valves, occur every six months which is within the optirum range for operability testing of these valves.
Furthemore, the ASME Cede, which requires testing be done quarterly and which has been adopted in 10 CFR 550.55a, also allows testing at cold shutdowns if quarterly testing
- is imoractical. Cold shutdowns can occur at intervals ups to refueling outages. Therefore, changing the test intervals' from quarterly to once every six months shall not differ significantly from the Code permitted change from quarterly to cold shutdown testing. -
Based on the considerations discussed above, the staff concludes that the alternate testing frequencies proposed above will give the reasonable assurance of valve coerability intended by the Code and that the relief thus granted will not endanger life or property or the corron defense and security of the public.
D.
Control Rod Hydraulic (CE) Systen 1.
Categorv B Valves 1.1 Relief Recuest The licensee has proposed to exercise the following valves at refueling outages:
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a.
Air valves from Reactor Protection 302-19A b.
Air valves from Reactor Protection 302-193 c.
Air valves from Reactor Protection 302-20A d.
Air valves from Reactor Protection 302-20B Code Requirement Refer to paragraph III.A.3 Bas 1s for Recuesting Relief These valves are solenoid operated and thus cannot be part-stroked. Full stroking could cause an unscheduled reactor trip. These valves are operated 145 times each refueling as part of control rod testing.
Evaluation We agree with the !icensee basis for not stroking these valves during power operation or during col'd shutdowns.
We find that the proposed request to exercise at refueling outaces only is warranted and should be granted.
1.2 Relief Reouest The licensee has proposed to exercise the following valves at refueling outages:
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'a.
CRH Scram Outlet 305-114 (Category C) b.
CRH Scram Inlet 305-1}5 (Category C) d.
CRH Scram Inlet 305-126 Code Recuire ent Refer to caragraoh III. A.3 Basis for Recuesting Relief These valves cannot be part-stroked because of their construction. They cannot be exercised at cold shutdowns because of system interlocks. The cold shutdown mode switch prohibits the withdrawal of control rods.
Evaluation We agree with the licensee basis for not stroking these valves during power operation or during cold shutdowns.
We find that the proposed request to exe*cise at re'ueling outages only is warranted and should be granted.
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'l. 3 Conclusion for Valves in D.1 The valves listed in relief request 0.1 are either passive and/or redundant valves. The optimum test interval for oper:bility testing passive and/or redundant valves was citemined by the staff, using actur.1 valve failure data an: standard probabilistic techniques, to be in the range of three months to 27 months. Refueling intervals, which have been proposed as the exercise interval for the valves in D.1 occur every 12 to 18 months which is within the optimum range for operability teaing of these valves.
Passive, as used in the above parag'raph, means any component whogeunavailabilityupondemandislessthanorequalto their unavailability has been found to be 10 gssive since 10-
/ demand. Check valves are considered p
/ demand.
Redundant, as used above, means the existence of more than one valve for oerfoming a given function.
Furthermort, the AS"E Code, which requires testing be done quarterly and which has been adopted in 10 CFR 550.55a, also allows testing at cold shutdowns if quarterly testing is impractical. Cold shutdowns can occur at intervals uo to refueling outages. Therefore, changing the test intervals from quarterly to refueling shall not differ significantly from the Code permitted change from quarterly to cold shutdown testing.
Based on the considerations discussed above, the staff concludes that the alternate testing frequencies proposed above will give the reasonable assurance of valve coerabi-lity intended by the Code and that the relief thus granted will not endanger life or property or the comon defense and security of the public.
E.
Feedwater Coolant Injection 1.
Category C. Valves 1.1 Relief Recuests The licensee has prooosed to verify that these valves are closed once every refueling:
a.
Outside Containment Check Valve 1-FW-9A b.
Outside Containaent Check Valve 1-FW-93 c.
Inside Containment Check Valve 1-FW-lCA d.
Inside Containment Check Valve 1-FK-10E 1249 041
. Code Recuirement Refer to paragraph III. A.3 Basis for Recuestinc Relief Cessation of flow would cause the loss of feedwater.
But even with the cessation of flow the position of the valve cannot be verified except with a leak test.
Evaluation We agree with the licensee's basis that stroking these valves is impractical during power operation or cold shutdowns. We find that the proposed request to exerci:e at refueling outages only is warranted and should be granted.
The valves listed in the above relief requests are either passive and/or redundant valves.
The optimum test interval for operability testing passive and/or redundant valves was determined by the staff, using actual valve failure rate data and standard probabilistic techniques, to be in the range of three months to 27 months.
Refueling intervals, which have been proposed as the exercise interval to the above salves occur every 12 to 12 months which is within the optimum range for operability testing of these valves.
passive, as used in the above paragraph, means any component
,whose unavailability upcn demand is less than or equal to 10-4/denand.
Check valves are 'onsidered pas}ive since the'r unavailability has been f;und to be 10 '/ demand.
Redundant, as used above, ceans the existence of more than one valve for performing a given function.
Furthemore, the.ASME Code, which requires testing be done quarterly and which has been adopted in 10 CFR 550.55a, also allows testing at cold shutdowns if quarterly testing is impractical. Cold shutdowns can occur at intervals up to refueling outages. Therefore, changing the test interval from quarterly to refueling shall not differ significantly from the Code permitted change fron quarterly to cold shutdown testing.
Based on the considerations discussed above, the staff concludes that the alternate testing frequencies propcsed above will give the reasonable assurance of valve operabi-lity intended by the Code and that the relief thus granted will not endanger life or property or the comen defense and security c. the public.
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042
_ F.
Isolation Condenser l
Nj@aVjfiI 1.
Category C Valves 1.1 Relief Requests The licensee has proposed to exercise the following valve at refueling outages:
a.
Make-up Check Valve 1-1C-11 gsis for Recuesting Relief Exercising this valve requires flow into the isolation condenser. Operating water level must be lowered to allow for additional water to be pumped to the shell. Lowering the water level reduces the safety margin of this component.
Evaluation We agree with the licensee's basis that. stroking this valve is impractical during power operation or cold shutdowns. We find that tne proposed request to exercise at refueling outages is warranted and should be graated.
The valve listed in the above relief request is either a passive valve.
The optimum test interval for operability testing passive and/or redundant valves was.detemined by the staff, using actual valve failure rate data and standard probabilistic techniques, to be in the range of three months to 27 months.
Refueling intervals, which have been proposed as the exercise interval for the above valve occur 4very 12 to 18 months which is within the optimum range for operability testing of these valves.
Passive, as used in the above paragraph, means any component e unavailability upon demand is less than or equal to whoj/ demand.
10-Check valves are considered passive since their unavailability has been found to be 10-4/derand.
Redundant, as used above, means the existence of more than one valve for perfoming a given function.
Furthemore, the ASME Code, which requires testing be done quarterly and which has been adopted in 10 CFR 550.55a, also allows testing at cold shutdowns if quarterly testing is imoractical. Cold shutdowns can occur at intervals up to refueling outages. Therefore, changing the test interval from quarterly to refueling shall not differ significantly from the Code pemitted change fron quarterly to cold shutdown testing.
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Based on the considerations discussed above, the staff concludes that the alternate testing frequencies proposed above will give the reasonable assurance of valve opera-bility intended by the Code and that the relief thus granted will not endanger life or property or the comon defense and security of the public.
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