ML20206G524

SER Supporting Employee Concern Element Rept OP 30111, Valve Closure

ML20206G524
Person / Time
Site:	Sequoyah
Issue date:	11/04/1988
From:	NRC OFFICE OF SPECIAL PROJECTS
To:
Shared Package
ML20206G037	List: ML20206G034 ML20206G298 ML20206G302 ML20206G306 ML20206G315 ML20206G319 ML20206G325 ML20206G330 ML20206G337 ML20206G344 ML20206G348 ML20206G352 ML20206G358 ML20206G363 ML20206G366 ML20206G370 ML20206G374 ML20206G380 ML20206G385 ML20206G392 ML20206G396 ML20206G404 ML20206G408 ML20206G410 ML20206G416 ML20206G419 ML20206G426 ML20206G429 ML20206G435 ML20206G438 ML20206G447 ML20206G453 ML20206G457 ML20206G459 ML20206G462 ML20206G466 ML20206G472 ML20206G480 ML20206G486 ML20206G497 ML20206G502 ML20206G509 ML20206G519 ML20206G524 ML20206G529 ML20206G534 ML20206G539 ML20206G543 ML20206G550 ML20206G559 ... further results
References
NUDOCS 8811220304
Download: ML20206G524 (2)

Text

.-

o

'

• i 4 .. " c yI l y 4'e, UNITED ' *.i ES

!j,

-/\ "f.

() E NUCLE AR REGULATORY COMMISSION W/,$HINGTON D. C. 00555 WeV./

s....+.

SAFETY EVALUAT:CN REPORT BY THE OFFICE OF SPECIAL PROJECTS ,

Ef';LOYEE C0fiCERN ELEl4ENT REPORT OP Mill. "VALVE CLOSURE TENNESSEE VALLEY AUTHORITY SECUOYAH NUCLEAR POWER PLANT UNITS 1 & 2 P

4 COCKET fl05. 50-327 Af4D 50-328 P

k I. 5.bfe:t Cate;;ry: C:e atiens (30000)

Sv:: ate;: y: ve:aanical E:ui:-ent Reliability /Cesign (30100)

Ele er.t: Vahe C1:svre Erc lem (30111)

E pleyee Concerr.: Ih-55-400-01 r Tne tap s fer E!e e t Re:rt CP 30111, cated October 30, 1936, is the

fcile sag e eleyce v

e.n:

Cer:e-n IN-s!.-4C0'01: Ceneric Cen:orn - Flow C:r.tiel Valves and '

I est: ati: esen/close valves in Units 1 and 2 '

(RhR. 515. CVC5. and RCE) do not completely close '

to prevert ficw of water, Average closure wt.s expressed as 96'i. C1 is concerned that tnis i

could be detrimntal to plant operation and

cesonnel safety, particularly after nuclear ,

ocerations begin, for exatole: instances where i ray routine /e+ergency maintenance activities i require t:tal or partial system isolation. t C:ncern is generic in nature, with no furtnea 4

specifics aveilable. l l

3 II. Su- ary of Issue i This is a geferic c rcern fr** 'n'atts $3r with C0ssible aaplicabi'ity at f  !

i $e*uayaF. Alt"Ou*h t*e 00*:e'n "eations :o'.h fl:W Control valves a*0 Aut *a*1: C e"./cl se (is0iatic*,) valves, chly 'ne isolati0n valves are Cesiga4: t: ;"eveat fl0d of water, i.e.. routine :P e-ergency Eaint.enan:e l ,

l a:ttvitie. at re:uire t:tal er cartial system isolatten.

6

Evaluat4:n e'e:t s:a1'y :-

.c.t> ':4-t e +: :, t e C: ::,': te eit e

+ .:45

4. 4:':4' ,  ::e ate:. 5 :e tne .a',es a e ces'; e: a-: f4:* : ate: -

a::: :3 :e t- ,'.5 : 5;6 5, vis-53-66, ae: ASvi Ser.tien II-;if5 e:4ti: , ,

l  ::ssitte :s car gn.

'esta

e is -t M :e: t: tre ente 0811220304 8911d4 PDR ADOCK 05000327 P PDC

. r ,

e The Se:voyah plant has an extensive valve leakage testing program in a::ordance with both ASME Section IX IWV and 10 CFR 50 Appendix J, which a;; ears to be reasonably effective.

ine ex:-essed c:n:ern of 95'. closure leads one to believe that the CI was tr :atly referrirg to tre 93'. limit switch setting on POVs. For slow a:tua i ; C.'s the pc-er ef f limit switch is typically set at 9E-99', to prevert the r: e n t e. of tre valve operator from damaging ths valve internals, for fast a:tuating MOVs, this power of f 's i mi t switch is typically set at 90-95*. for the same reason. Althougn the limit switch is used to ceecergize the valve ector on the opening stroke, the torque s ,. i t c h is used to deenergi:e the valve on the closing stroke.

The S e:;ucya h raintena. ace training for both electrical and mechanical raintea.ance workers covers not only the setting of limit switches in a::crda ce witn Secuoyah raintenance instructions (MI 11.2A, B, C, and 0),

but also Oc.ers the theory on why the limit switches are set at 98-99'. for s10 a:tuating MOVs and 90-95'. for f ast actuatirg MOVs.

IV. C:*:lusien THe ' 0. 0 staff telieves tnat the TVA investigation of this concern was 1:e;us.e an: treir resolution cf the con:ern as describcd in Ele ent

^

,e::rt C? 30;;l is acceptsb'e #0- restart, t

,