ML20085M746
| ML20085M746 | |
| Person / Time | |
|---|---|
| Site: | Fort Saint Vrain  |
| Issue date: | 06/17/1975 |
| From: | Brey H, Swart F PUBLIC SERVICE CO. OF COLORADO |
| To: | Howard E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| References | |
| RO-50-267-75-2A, NUDOCS 8311090194 | |
| Download: ML20085M746 (6) | |
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P. O. Tox 361, Platteville, Colorado 80651 A','1 \\ ! i 'W?
, Q-l_\\ - ,\\ I j,].~,:' ' V,. J, June 37, 1975/.O L_] 'r* . j*/ p. ~ - ",,. <.~j. c. ~ h) lir. E. Morris novard, Director ./f ?:ucicar Eerulatory Comiguion '\\r 9%/(l]h. A FI! AL IIH" :'1 FICATIC; Or l'6$.. dim:. F hoih recondary coolant loons appmred t o It isninted ninul tmiecunly by PPS act ion. i m ation 7.6. Thin is identi t ivit es au ruu,ocil rvcnt, per po r,rrnph C 3 imd non-rout t oe report s. l l l Ci.11TIONS PR10R I;outine ShutJain l Tu OCCURRET:CF. _ _ Steady State Po'.ter Itoutine 1.oad Changa 110t Sliu dovn j Other (spec.i fy) X Cold Shutdown Kefuc33ng Shutdown l Routine Start up 5 9 e
l' age 2 The i cij or plant. par.- tbrs at. t he t ira: of t.1m event were as follw : l'e.te r PTlt, g _ _ _ 1 L't h F.I.rCT, 0 f;L'e Secor.:!arj Coolant Prc: sure 1500 p t. f.c Ternper.1 t u re 200 F fl o.e 150,010 t/hr. Prl:.iry Co:.lant P. car.u re ~ 150 psit Temperatu.. M5 'F Core la!.ct 100 ' F Co re-Co t.. e t l Fl e' _ 0_ _. h/ht. 0 g a b 'l l l I m,..,
Pane 3 ) D!: Sci: 1Pf f G : Dr O ct.C : 1: uere operat int; at scif-turbining I and Loop 2 lielina Circulat ort, The f eeduater f lo.e t o f.he 1.oop 2 st cari ; enerators was isolated. "the L c; condition. The Joe;- 1 ute.au nenerator had 150,000 t/hr. of fjo.. t.he beartu;; cat er a: ctre.ulator for 1.oop 2 should be It van de t et uiund that. lucrea :J n; :he llel.inu Ci rculat or tested f or acce..t ahic cyrat ion prior to .instruc.ntation had becn set up t o mon ! Lor t.he Speedr. After the recordby. perf emunco of thin t.est.both bearin;; vater pumps vero tripped for one I!elium Circulot.or auxillaty loop and t he tuo inch;eca coanted 'down and vere aut o-- The Loop 2 shutdeun isolate.1 f ree the ato:t] inries, per nore".1 Pps act inn. sinnt.1 uns received and the proper alar' <, and act ions occurred. problems rete Short.. y (5 ninutos)follu...in:; t he Loop 2 accumulator test,eac cubsequently l .This probict er.}crienced with the buffer hellun syst m.v t ern ined to be due t o valve ponit J 11ecct or Opervt or shut do"n the Loop,1 11oliu.n ci rc ulat ors and ret urr. valves. Tho Thit uns done and all PPS actions and indicatione in an ordarly r:aar.er. appeare: normal. ntor not be;; ai the process of returnin;; the Loop 2 Helin', The Ib actor 0; When t he buf fe: helium trips self turbJning conditicn. Circulators to the cleared on one helier circulator the Loop 2 and berrin; water trips ven This is non.:a1 bec. ur e shutde:. cicared and initiated Loop 1 shutdu..n alar. the J f ret an t 1.th Jodout r;tc (Jn the PPS) was clonrod of a Loo ~ 2 trip cud tho Lecp 1 trip was not now leched out. (uith circulatorri belo;; stcrted nou cxpr.rienced proh]ct The l oop 2 re. lie-L' hen th.f r. eceu! : d the bvf G.r helien system) and uc're r:? nun 11y shut. doen. the PPr initiated a Leop 2 shut-dot n r i m Th b shenld no'; have harpe.Td, because the l oop 1 secondary coo 3 ant loop.use already chut d e.tn. Actual Jeap isolation did not occur but appeared t o havu happcaed as indicated by the annonicator synten. 6 L 9 9 J i t LJ ~$
Pap 4 7 s, (N a (0) \\v Ununual m rvice Coud. AIt.*r rf C.'.!'SE ..__.. lie n ! r,n +- ]nclud.i nr, 1;nvi ro n. X .o r..... ._T_ _G. __:. ( ;:( l'. _!;anufacture __, Component railure inntiilatien/ Count. _0ther (rpecify) Operator Procedure cre prevent ed fm, cir ultan( ously icolating, in" sign 91s, by a "first Uoth r,eccadary ec.olant loopr te shutde, .i np u t Icolat fon of both eeen thee:;b both have Jegi tir i c syst era epo r. '.ed pmr"rly t o prevent.loors as describ This 1ct sy.<.: er. of the. isolated r.J arm action to occur ir; roperly s hc n rentart seccudar coolant but allo wd the locp v., attuptol. existence event 'as caused by Lt.e inventigntion revealed tbnt t.hs (T1UI.) " Loop shutrio.:a" ci rc u i t s. Subserpmnt PP S I' irs t-i n-Ei t h--1.e cheu t "remorn!" of an inhibit .;!"a11 in th of a "rac.t" thc This " race" hns been resolved by delpyi'. "[d3!ioD of a CJIMOilCI MCI'D S I' b ? C011 UI OI c" -. of 11"' l' A l b i t lon!. entw h to [Or 3 fiill(MecGr.d.I.y the correct 1y lwfoie the buf f er t v:mcintors chich delay thet o "ve r " t be "l'i rat - In-ui t h-l.oct cut cc: input. allov ihe proper nirnal.;ignal vooid be paored t o the corgierentary t he coatradict or, e 4 4
) 1 a / f ) ( ) i i \\/ ut L Pane 5 i t A':?,1.Ym i. OF ocrt':.': GCI'.: t o recreat e t bc event. A r,crien of operat ione. were p"rf ori'ed t o at t ep.pt Tin evcnt. could im recreated at vi!), a n.1 neveral di f ferent (but sir ! h int o the t o y,in ndd Irional. Int:it i 1 ir e t brotuth of event r uvi e pe r fm, ? the ni !,nal t ranr1 t sequeues, Ulriedcly it van concluded that c i.on y.h i s tiren'" vent the prebler. circuitry differed by junt the Id;,h cpeed logit preveu: the "/i" lo",1c frem r.uton!!v exelocive "tC" n, orork required to (a 100,3 1 trip in tis "A" lenic contreiicting,the cenple#cntary "U" Jor,ic inhibita a loop 2 trip in the "n" Jopic and v:ce versa). Ihe enllect n; Joad of thn output buffcr tr.w i< crs Cal ac ! t ort, vere cdded acror: long enough to alle; t he prn, - which delayed the renoval of an inhibir jmt 6 1'csed to cc Wi ory rd r,aal Ut'"l', rir
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'ificaiion, ti,e regner the co 1b cutav, inpat. AfI :-r th i r V:rie. an.I no conflict J r. ne'ic:. or c1:v. u cor rc. a r.e ' o of
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'nnt -1 irdfcatIoos. <:eque ees vete g rfarrod, uit on1x enifcra(d I ml ~ n f t< recor,niae ihet tiic p'robler 11 % inport. nt t-the onlii.tly reqrcnce of: loop (circuletorn and reedwat c) 1. Shutt. Inn doun t!:e let. e, u n' ba <,ut d xn) 2. Shutt in: doun the 2nd loe,. (cire"12 terr pr? roeA re r 3. 11ectarting, t he J r.t. loop (c ire t I nt or.s). occur, " rc< it ro<1ui ren t 1:.- r.:13 ret Th.- requonce ven!d norm 3.13 r.cve, Um ert bol, n, the cJrcu't down at one point in ti Iout conf 'at inc circul a1 orr be rhut ic.11flent loa alloc der,cribed :,er,r<ence i o occ ur el! indicalions. C013'.ECTIVE ACTIOS: Sec " analysis of occurrences" TAILURT. DATA /S1IllUd REP 0;1TfD OCCunnrNCr.S: None PROGR_idO_IATIC IMPACT: j None CODE 1MPACT: None / 0 D-i M^ Approved:, _(([tg.d M'^ p
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F. U. Swart, Recor.uended : Muc1 car Production H. Larry U'ey Supt. Superj ut endent-Operation s Public Service Company . Fort St. Vrain Uuelcar of Colorado Generat lun St at lon .....}}