ML20037B543
| ML20037B543 | |
| Person / Time | |
|---|---|
| Site: | Dresden, Quad Cities  |
| Issue date: | 04/24/1975 |
| From: | Ziemann D Office of Nuclear Reactor Regulation |
| To: | Abel J COMMONWEALTH EDISON CO. |
| References | |
| TASK-07-02, TASK-7-2, TASK-RR NUDOCS 8010170704 | |
| Download: ML20037B543 (4) | |
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APR 241975 NRC PDR TBAbernathy 0:
0-10,)50-237, f
Local PDR SVarga t.r Locket tro.
50-249 un
(-254 Docket ACRS (14)
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ORB #2 Reading TJCarter iir
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Cor=onwedth Edison Company OELD 1
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Mr. J. S. Abel OIGE (3) 1:uelear Licensing Administa.
- DLZiemann I
Ioilin.c Water Eesctor:
PW0'Connor P. O. Eox 767 RDSilver Chicago, Illinois 60690 RWReid RMDIggs Centlemen:
JRBuchanan "L.
Our review of recent subrittels regarding the reevaluction of eterSency core cooling systen (ECCS) perforcance in accordance with 10 CFis 50.46
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indicates that certain additional information was required in order for
}!:j us to conplete our evaluation.
This letter is to inforra you of one part jjji of the evaluations that have been submitted that has recuired additional informstien.
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In perforning the evaluation of single failures of LLCS ecuipcent required by Appendix K to 10 CFR 50.Section I.D.I.,
the ef fects of a single f ailure or operator error thet causes cny manually-controlled, electricsily-operated rigi; valve to cove to a position that could cdversely af fect the ECCS must be considered.
Therefore, please review your submit tals regarding ECCS; and if this consideration has not been specifically reported in the past, your bpcor:ing submittal rust address this consideration.
Include any proposed,
plant codifications and changes to the Technical Specifications that mirbt he reouired to protect acainst. any lose of safety function caused by this
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type of f ailure.
A copy of Eranch Technical Fosition EICSB 18 fro::: the af U.S. Fuclear Fepulatory Conmission's Standard Eeview plan is attached
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to provide you with guidance.
This recuest for generic inforr.ation was approved by GAC under a blanket clearance number E-180225 (R0072); this clearance expires July 31, 1977.
Sincerely, Original signed by Denals 1. Ziemann Pennis L.
ierann, Chief A
Operatinp, Deactore Eranch 47 I;ivision et Feactor Licensing (CCS l,E rnelosure:
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!!r. Charles Whitmore President and Chairman Iowa-Illinois Gas and 15EU5j Electric Company
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206 East Second Avenue
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Davenport, Iowa 52801 John W. Rowe, Esquire Isham, Lincoln & Beale Counselors at Law F ~ ~~" :-
One First National Plaza Z-Chicago, Illinois 60670 g...._..
Anthony Z. Roisman, Esquire EE"l$
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Berlin, Roisman and Kessler 1712 N Street, N. W.
Washington, D. C.
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Moline Public Library
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=ia Morris Public Library 604 Liberty Street Morris, Illinois 60451 g.
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BRANCH TECH *i! CAL POSITION EICSS 18 h: :..i=>
4EZQ APPLICATI,0N OF THE SINGLE FAILURE CRITERICH TO PANUALLY-CONTROLLED ELECTRICALLY-CPEPAIED VALVES
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BACKGROUND r=x=
Where a singl"e failure in an electrical System can result in loss of capability to perform
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a safety function, the effect on plant safety must be evaluated. This is necessary regard-
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11 css of whether the loss of safety function is caused by a cocpenent failing to perform a '
[5 3:24 requisite mechanical cotion, or by a component performing an undesirable mechanical motion.
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[f5 T This position e'stablish'es the acceptability of disconnecting power to electrical components
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of' a fluid system as one means of designing against a. single failure that might cause an on-
" f5E desirable component action. These provisions are based on the assumption that the component
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is then equivalent to a sithilar component that is not designed for electrical operation.
E" e.g., a valve that can be opened or closed only by direct canual operation of the valve.
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They are also based on the assuc.ption that no single failure can both restore power to the electrical system and cause occha.tcal cotton of the components served by the electrical
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- system. The validity of these assun.ptions si.ould be verified when applying this position.
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BRANCHTECid!CALPOSlTM j.
1.
Failurcs in both the " fail to function" sense and the " undesirable function" sense of 9
co:rponents in electrical systecs of valves and other fluid systen components should be considered in designing against a singic failure, even though the valve or other fluid system component may not be calied upon to function in a given safety operattonal
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sequence.
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2.
Where it is determined that failure of an electrical system component can cause
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undesired r'echanical motion of a valve or other fluid system co:ponent and this motion results in loss of the system safety function, it is acceptabic, in lieu of
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design changes that also may be acceptabic, to disconnect pcwer to the electric systems of the valve or other fluid system co: ponent. The plant technical specifications should include a list of all electrically-operated valves, and the required pcsitions of these valves, to which the r'equirement for removal of electric ' power is applied in order to satisfy the single failure criterion.
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3.
Electrically operated valves that are classified as " active" valves, i.e., are required
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te e.atn nr close in varie,vt safety system orantional saquences, but are ranually-
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._ T included among those valves from which powcr is removed in order to ocet the single failure criterion unless: (s) electrical power can be restored to the valve; from the
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E main control room,(b) valve operation'is not necessary for at least tm mi..utes following occurrence of the event requiring such operation, andh) it is demonstrated 7A-27
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that thera is reasonable assurance that all necessary operatcr actions all) be pir-j fonned within the.tlee shown to 1,e edequate by the analysis. The plant technical jij j,_
specifications should include a list of the required positions of r.anually controlled, g:
electrically-operated valves and should identify those valves to which tht: require-I ment for removals f electric power is applied in, order to satisfy the single failure
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criterion.
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, k en the single failure criterion is satisfied by removal of electrical power from
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'talves described in(2) and (3), above, these valves should have redundant positten gv[5fi.^
indication in the main control rood and the position indication 5,ystem should.itself, meet the singic failure criterion.
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The'pnrase " electrically-operated valves" incit. des both valves operated directly by an E
electrical device (e.g., a motor.cserated valve or a solenoid-operated valve) and those
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va1ses ccerated indirectly by an electrical device (e.g., an air-operated valve whose air supply'is controlled by an electrical solenoid valve).
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RfrERft:CES 1.
P.ctr.orandum to R. C. DeYoung ar.d V. A. P.oore from V. Stello, October 1,1973.
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