ML20042G582

Insp Rept 50-461/90-09 on 900412-27.Violations Noted.Major Areas Inspected:Circumstances Surrounding Improper Withdrawal of Control Rods on 900411 W/Main Turbine Bypass Valves Not Fully Closed

ML20042G582
Person / Time
Site:	Clinton
Issue date:	05/09/1990
From:	Lanksbury R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
To:
Shared Package
ML20042G579	List: ML20042G578 ML20042G582
References
50-461-90-09, 50-461-90-9, NUDOCS 9005150105
Download: ML20042G582 (18)

See also: IR 05000461/1990009

Text

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. . .: U.S. NUCLEAR REGULATORY COMMISSION REGION III Report No. 50-461/90009(DRP) , . Docket No. 50-461 License No..NPF-62 Licensee: Illinois Power Company 500 South 27th Street . Decatur, IL 62525 Facility Name: Clinton Power Station. Inspection At: Clinton Site, Clinton, Illinois Inspection Conducted: April 12-27, 1990 Inspectors: P. G. Brochman R. D. Lanksbury- S. P. Ray . - F. L. Brush J. B. Hic j O m . Approved By: D. L sbury, Chief CIl40 Reactor Projects Section 3B Date * , . Inspection Summary Inspection from April 12-27, 1990 (Report No. 50-461/90009(DRP)) i ,J Areas Inspected: - Special safety. team inspection by the resident, . Region III, and NRR inspectors to review the circumstances surrounding the improper .i . withdrawal of control rods on April 11, 1990, with main turbine bypass valves Lnot fully closed. . ' ,Pesults: The safety significance of this event is derived from the lack of-attention to plant indications during important evolutions by licensed personnel, not believing plant indications, not informing supervisors of unexpected plant response, and the scheduling and controlling of complex and safety significant evolutions during shift turnovers. The actual physical- safety significance of this event on the reactor core was minor because all of the control rod withdrawals made during this event were in accordance with the rod pattern and were at a rate which was more conservative than the rod pattern control system limits. Two apparent violations were identified (failure to follow Technical Specifications 3.1.4.1 and 4.1.4.1 - Paragraph 8; failure to follow procedures or develop adequate procedures - Paragraph 8). , , 900515o105 900510 gDR ADOCK0500gg/g1 , - e . . , , + , - _ . _ _ _

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l DETAILS . . . , . . ' J , ff' " %; . * * * ' _ , 1. persons Contacted- , ,, .c . . ' . O \\ i k. [', Illinois ~ Power' Company'(IP)' " ,; y , . , , ,. , ,, , , ,. '

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• J. Perry, Vice Pre'sident >

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l*9 7%x% j . J. Cook,~ Manager, Clinton Power. Station.. b[ .

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3; R.4Wyatt, Manager, Quality Assurance , .,- % , .J

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, ,' " '*J. Miller, Manager, Nuclear: Station Engineering d 1 ,J '1:e "j ' ' s .

• Fl Spangenberg, III, Manager; Licensing and Safety-

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• R. Morgenstern, Manager,eScheduling and Outag'e" Management a=

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• J. Palmer, Manager, Nuclear Training

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• J. Palchak, Manager =,, Nuclear Planning and: Support 3 . +

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• D.< Morris,aDirector,L. Plant Operations

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• S.' Rasor, Director, Plant Maintenance

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• D; Miller, Director, Plant Radiation Protection - ~T

1 'a . - < < ..> . *J. Hansker, Director, Planning and Programming. ' [ I,, , . < '<

• R. Phares, Director, Licensing'

' ' * - C, m. _ - y' '

• S

Hall,; Director, Nuclear Program. Assessment

1 . i

• K. Baker, Supervisor; I&E Interface-

> ' s Soyland Power ' -

• J., Greenwood, Manager, Power Supply

" .The inspector also contacted and interviewed other licensee personnel ' + , during the course of this inspection. .

• Denotes those present durin'g the exit interview on' April 27, 1990.

. e 2, Purpose (41701,~71715, & 93702) The purpose of this 'special team inspection was to. review the' circumstances surrounding the events. on' April .11,' 1990,- when several control' rods were !

withdrawn'during a reactor ~startup while the main turbine bypass valves

' werelnot fully closed.

O The inspectors interviewed the shif t crews, training department personnel and managers involved.in this' event. The inspectors developed a chronology . - of events and analyzed 'this event for its safety implications. The ' inspectors'provided augmented monitoring of control room activities , during the restart:of the reactor. ', ' , 3. ! Description of the Event' , , , , , '

The following description of the event and the chronology were developed

, . 'upon~ review of. operating logstand strip charts, and interviews conducted. t ~ during the inspection. Some of the times listed are approximate and,are. ' f based upon a consensus of individual memories of the event. All of the . < y times listed are CDT.

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3 - - ; , 3, , , ' ' < ' ' r,s - ,. . - . . - . - . , p i - ' 1 p, , 4,y# .On April 10, 1990, at approximately 11.00 p.n., the midnight shift . f c ' "A'! reactor operator (RO) (the R0 assigned to the control room panels . . controlling reactor power.and monitoring equipment, turbine / generator. ,, ' controls, feedwater controls, etc.) assumed the watch. The "A" R0 had

noted during the shift turnover that generator load was at 105-110 MWe,

. , ~ reactor power was at 18-19%, and the electrohydraulic control (EHC)

i

system, generator load set was at 300 MWe, .He also reviewed the plant . ' ' procedures,-inplaceatthattime,inpreparationforcontinuingR0 the % 4 power ascension. After completing the procedure review,' the "A . !* ' noted that reactor power had dei:reased to approximately 16% due to xenon; ~ ' . i l' ' building in (increasing). He then commenced' withdrawing control rods *

with.thecline assistant shift supervisor:(LASS) acting as th'e independent a

i verifier. ,During the interviews, the inspectors uniformly were told thatt i 'p, F the" purpose of,the independent verifier was to ensure.that the correct - L ' control rod was selected from the rod withdrawal sequence and moved to

, , ' < the correct location.; .> On' April 11, 1990; at'approximately 1:30 a.m., the "A" R0 stopped ' "i * - , gT withdrawing control' rods with reactor power.~at 23-24%. During this time- " - ' period he did not make any adjustments to generator load set. At"this- 7 - Ffo point the low power set point (LPSP) (approximately.22%)'of the rod '. 'i, e< u pattern control system (RPCS) had 'just been reached'and there were a, - e

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number of surveillances that needed to be completed, before the. power > ascension could be continued. A repair to a. feedwater pump. mechanical- . J overspeed relay also needed to be completed and tested prior'to increasing' , 3 . L ' power. - r

s y , 'Atapproximately6[30a.m.,'the?"A"R0completedtestingofthefeedwater ~^ ' c 7, l pump mechanical overspeed relay. Fifteen minutes later, at 6:45 a.m., e ' t v wW 'the shift supervisor.(SS) instructed the LASS to recommence the power 7" ascension with the goal-of reaching.35% power, prior to the end of the > ' , shiftL .TherLASS in turn instructed the "A" R0 to commence withdrawing g control.' rods, in order.to bring'the reactor up to approximately W 3 power. The "A" R0 complied and commenced. control rod withdrawal with a

'

, V, day shift staff assistant shift supervisor (SASS), who had come in early, 4 " .: acting as the independent verifier. - At this same time, day shift operators were arriving an'd began the ' 4 in , process of shift turnover (which included' panel walkdowns, a shift ' P ' briefing,- log re~ views, etc. ). Due to this,ithe normal senior operator ' J oversight of this evolution did not occur. In addition, there were - i ' 1 also more people in the control room;than normal. At around 7:20 a.m., ' ,,

the normal day shift-SASS needed to get.his turnover from'the SASS who ' ~ i

~ was acting as the independent verifier. The LASS had the' day' shift shift , , . , technical adv.isor (STA) relieve the SASS as the independent (verifier. :At i4- P about 7:25 a.m., the "A" R0'noted that generator load was about 200 MWe. ' - He has'also cognizant that generator. load set was stilb at 300 MWe, At 4 B this same time'the' LASS shift turnover had just been completed and the . ' ' y i midnight shif t.' LASS left.. Prior to leaving, the midnight shift LASS } reminded the day shift' LASS about surveillances that were due at 25% pooer and also informed him that they had received permission to continue- l thi oower' ascension =to 35% power., lhe day shift LASS started reviewing + - , , 5, I 5 g 3 . %' ' < . a

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, , . , Nf;b , .A ' < r , , , & y; , 3 s y, y gM % _. . , . , l ' ' , < , ys 1 the" power ascension ' procedure;being~ used from the point where they. p " were at:to seeLwhat needed to be; completed next. He did'not go backc t _ " " '* ' 4 .

-andfraview the

portion that"had already,beenidone. -The LASS was engiged

1 . Q~ E'.- inimaking^planseforithe work to be accomplished on dayshift. 1Because of E ~ - R M( - this he' did not adequatelyLmonitor;overall unit. operation by observing plant indic3 tors;inLorder to detect:any unusual;or- abnormal trends.; ' ~

s , At hroximately '7:28 a.m. c the, reactor reahhed 25% power.' ;Since. '. ~ " pg - > 7 permission;had'already been given toJcontinue"the p wer ascension ~ i, . V to 35% powerhthe '!A"-RO continued withdrawing control rods. Ati > '"m ' about 7:30:a.m'.;, the day shift SS relieved,the midnight shift SS.; _ / ' - + Eight minutes:latersat'7:38-a.m.', generator.eload reached the load set'and c c ^ ' M - the fii'st' main turbine'bypasstvalve began tolopen. This went unnoticed

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' i , . O' ' by"anyone,(includingcthe LASS who was respons~ible for monitoring overall- " ' plant responsef to_ the 'ongoi_ngievolution; and the "A'F R0 continued to; ..h ,. 4 " ' o4 5 withdraw' control:rodsa At about 7:40 a.m. the STA noted that generator- ', 4' , load had not been;; increasing even though control rods vre being withdrawn - . andLreactor power was increasing.X He' questioned the "A"- RO ^about'this and M,' ,. ' ' twasitold it was due to'the computer display 1 control system (DCS) not, l @' 7 updating properly. Even though the'STA was_not' satisfied with-this answer, - ~ he did not pursue it,any further. At 7:44 a.m. , the first bypass valve, - - . , ' reached he full'open position and the second bypass valve began'to open $ . , as control: rods continued to be withdrawn. ~Three minutes later at e

reaching.ap,thenlast control rod withdrawal was made with reactor power % 7: 4Ea.m., m

" % c . ^ proximately 35%. The STA again questioned the "A" R0.about? b x 3; p the fact that generator load had not increased. TheD"A" .R0 attributed ,* W the: problem to lockup of the DCS-and/or xeno6 buildup. During' control ' .- ._ j rod withdrawals earlier'inithedshift? the "A" R0 hadLnoted that generator ' , T ' load increases were not as;1argesas expected. 1This1 fact'was attributed M--Ql^~ to the fact that the'conttbl rods;being withdrawn were peripheral l control, - ' - o rods with little rod worth;and"due to xenon building in. During the(time T, , ,. that the bypass valves were open a' total of.14-17 single notch, gang mode, <c . % control; rod withdrawals;were made.' ;With, control' rod withdrawals stopped, P t/ the STA left the contro1 area. The'"A" R0 obtained a' process computer' - - printout. (00-3) to verify: reactor power level. The 0D-3 printout

indicated that reactor! power was approximately 34". 1The "A"< RO: waited - ,3

approximately three minutes and then/obtained a second

00-3 printouty

Thisiprintout indicated that reactor power?was approximately 38%. lThe s ' , % C "A" R0 did.not check what generator , load'was ande had not looked at that , '; .

j

e ' f i . parameter ~since 7:25 a.m. 4 " a , .' , E At 7:51 a.m., the midnight shift "A" R0 commenced'tupnover t'o:the" day shif t " A R0. As part!of the turnover, the "A":R0s walked down all ' ' - , the -panels in thetcontrol room. This included the. panels containing , the indications that two1 bypass valvec Jere open: They, stopped at those: F, ", p'anels and discussed , items of interest'but.neither noted that the bypass- ' .~ valves'were:open. The "A" R0s continued tee turnover process 'until" ~ ' , . 8:30 c.m. when the midnight shift "A" R0 was of ficially relieved by ' ' %' the day shi_ft "A!' R0. - , < ,f^ ' At about' 8:00 a.m. , the day shift' LASS assigned the extra day shif t ' % (RO (referred to as "B prine"':R0),the task of performing the portions ~ ' y , of.the powe ascension procedureLnecessary to lineup balance-of plant a 's ge i 3

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' -R. v + m x' ' - Ki . .- , gy):lf ji) ~3- , ' ' W ' y, < , , , 4 .- 1 {; b ' (80Pyequipment. :The "B" and "B prime"l R0s, are f assigned!to the' contr'o1 ~ f , * . room # nels controlling; balance-of? plant systems. Sometime between i + s ., p 8:00 a.m.> and 8i30- a.m. ,: the "B prime" 'R0 did ' note: that 'there were bypass 3 sI wa s h 'QL ~+ . valves open,'but apparently did not' recognize?the significance of this h>; 9 >: fact.9 At approximately; 8:33 a.m. ,ithe open bypass valves were discovered ,

by the two "B" R0s while performing-panel' walkdowns as.part of1their shift-

~ " N . s turnover. ~ TheyLimmediately brou0htcit; to the attention of the midnightJ 4 , , . y yqM shift "A" R0 who,was;still in:thelarea. The operators recognized that .

1

~ ' ' en the' generator load; set was 'too low.1 Af ter a brief discussion !as'to whether-

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any control rod withdrawals .had .been;m6de sithithe- bypass valves 0 pen (the

' 0 " / v' midnight shif t. "A". .R0_.did not remembergmaking any), the midnight'shif t "A'.h cn - . RO increased ' generator' load set, in order to close the- bypass valves. .At ys o, . E _. -_8:35 a:mi, the generator load set was increased to tapproxiraately 520 MWe. v4 t ?O 'By1 8:36La' m. ,. the bypass valves were fully closed andf generatorjload T ' . % %, increased to:approximatelys 300 MWe.- ~

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, S , ThezSS ' directed that the; high speed l computer monitoring sysdem' GETARS l " ' . . 7 ;* . be checkedito determine if any control rod withdrawals ha

f, r with the a _ , g^ y < i;f _

and' they indicated that 2.4-17 controlsrod withdrawalst had occurref j Fw with bypa_ss valves;open., The exact nu:nber of rod withdrawals could hot;be- t, j .40. determined;because the ffirst. bypass. valve; started tr apen sometime^ during- pi fa series of three rod pulls.' The Operations depart e mana Of f * ' senior plant

1 '

' s ' notif,ications~of. the initial facts to the NRC resi. dents and' gement made t . ? , p1 ~ ,i i 9A man'agement.. f 0perations4 department conducted a critique at 4:00 p.m. Ythat " .j Q -days to-review the evept? "Senionflicensee management was informed of the

Q. . gl% IA initial facts of the event; however, the results of the cHtique and the

' . r ? Isignificance of theLissuesLinv'o'lved in this event (reactivity control. - q$ . " [ performance of licentled operators, and conduct.of' control room evolutions) ' x were not communicated to senior management until they were expressed by ~ on- i, pp NRC' Region III'managemint at a previouslyyscheduled meeting Ahe next day ~ y .] r ' - ( ) y with licensee corporate management. 1 After reviewing 1thisj nformation,'. (. j f 4 , "D licensee. management decided to shutdown'the ' unit and -implement the . ' k "m

4 y o L i, corrective ~ actions ~ discussed in(Paragraph 6. ,The shutdown was commenced ,a , ?O u' at 7: 34 'p.m.' gn April 3h 1990,^ byl inserting. control' rods; Theigenerator j

, !* ~ was:of f-line at ,9:42 p.rn. .that dayc The unit-was subcritical2at.6:407a.m. f? "

on April'141 and. reachedccold shutdown'by Ej45 a.m. on Apri1F15',1990. ~, - u . , . 1t ' <y ? ~ y . r - \\ ' ' ,l .N,) 13 n ' Sequence'of EUents. !" , i J Y l4. ' nR ' ~ , , M

The1fohowing 'is a brief sequence o'f events: . c "" d ', . 't e t wo is - , , , _ April-10f]990 cg' D . . . . , ,4 u ' , , - _ e , s. y <% , s. % . ' % ~U 11: 00 p.mc "A"Dreactor operator (LO).took'the shift with the.generatorj r

. - , , 'N H at 105-110 MWe, reactor; power at 18-19% power,cand load set' 4 4' , , .E _at.300 MWe. , Commenced withdrawing control rods. ;Line: , ' . assistant shift supervisor (LASS) acting'as independent '. A ' + ". , &, . verifier, - m r - >i , w ,. , q f - 4 /' ,

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, .m , .. ' . $,b 7 '%", " a s - , , , i , k[ S7T - l April 11. 1990[" ' ! ' ' ' gp .e j ; . . ' . , . k' [ g 4 ~ ; s . '1:30 alm.g. ' "A" R0 sto'pped; withdrawing control rods with reactor? ' T , LV- power at 23-24% and..just above the low power set point . , , (LPSP) (approximately 22% thermal power)tto perform y 'r- ,

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. surveillances. Generator load was.125 MWe. 7~ p z , 'D 6:30 ai "A'.! R0 completed testing'off a:feedwate'r pump q , , Wm, , . " ' ', mechanical overspeed relay /.that:had been repaired. m . s . , , .b E ,.

• /Shiftsupervisor(SS)1directedth'e'LASSwhoinstructed'

- 3 6: 45Da.~ ne " &' - the "A" R0uto commence' withdrawal of control rods to . ' 3

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t iincrease po'wer, with the goal of reaching'35% power prior-

. ' fo the end of the' shift. Control room turnovers (had be -) '.. . " . f or some positions. ' Staff assistant shift supervis"oF ' gun - ~ >< u '1 ' "

" ' f(SASS)lacting as independent' verifier. 4 l

, 4g - - ,#, _ , - 1m 7:20 a.m.- 1

Day' shift shiftltechnical advisor (STA) relieved, SASS's'

~ s% e- t ~ o y b m e, . as tiie independent verifier, - ' . , n o - L. a ' > - + .c.. . . . , n.. 1 . . - ' ' -a w "7:25 a.m. "A" ROTnotedithat generator: load wasL200 MWe. A"A" R0 v ~" .t y. 2,.- $? 57 h) .ah o wcs cognizant that' load set"was-at,300 M9e'. ! Midnight i TdQ A LAS$'offic[ ally relieved. 4 .p . %; ' .. , , ,.

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+ - ' c'.7:2S a.m.T lAchieved25%powerc Continuedsithdrawing contro1 * N m i[ ' ' w . gg rodsito 35% power. 'i ' ' ~

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n .v , . . 5 > p, f_, 9.7;30 a.m; . Midnight shift SS relieved by flay shift'SS.( ' % 1" u . , ' , c e I ' Y . 4 Y - .' ). . . , '17f38 4 "' 'Firstmain'turbinebypass.vafvebegan'toopen. ' P f ' s t

y~ c ul- 'T i~ This fact was not' observed by the'"A".R0 or?the STA. ' t . g (>4, . Controlirod.Withdrawa?'sicontinued.,j " "s EP . , - QaYfM m

g, + ,, _ 41, . _ . i 7:40 a.m3 , STA" questioned YA",R03about-generator' load not ' f;[N % A !increasingJ ~ "A" R0' attributed this' to= displa9 control b - ' '0- ' ' ' system locking uf(not responding). ] pc , ' o

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,A 7: 44 a.,In. First bypass valve was fully open.' _ ' 4 c s. ' , , y.- . s1 ? . , Control rod withdrawals ended. 1 t 7:47 a.m ' Power"reachedi35%. . y STA again questioned "A" R0:on why< generator load has

& not increased, c"A".R0 again attributed this: to display ' , Y' left theicontrol area. '."A" RO roccgnized generator load . . controlo systCocking up- or a xenon building in. STA @ at 200 HWe '"A" RO obtained a computer printout of-

4 . therma : power level l(00-3) which indicated it-to be l

ds

34L

t h" ~ 7:50 a.m. "A"'R0'obtained a second.0D-3 which indicated-reactor. 4 ' .pewer to be 38%. ' j ' - - - < y, ,g . 3 q , ,

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y_ , , [ Q i ' x e ,, 14 ,' e 4 5 w A" RO commencediturnover to day shif t A" R0, ')

7':51 a.m.

' (" including panel walkdowns. , -m t ' - , '

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00 ' a. m.'

Extra day shift "B prime" R0 assigned to perform. required 3 .- balance-of plant' equipment' lineups by LASS.. , -7:51 to' Both "A" R0s stopped in front of panel?with bypass valve-

• ,

8:30 a.m. . position indication and looked at and' discussed' items- t.1 " .of^ interest. Bypass valves-were not; recognized as'being d ' . ' w + , - " open. < e p. .; - -8:00;to 'B-prime" R0 noted bypass valves open butidid not recogniz'e i ! ' ' " - L . 1 ' 8:30:a.m. significance of this fact. ' , ,, ' "

4 a- , . .. . . r . . i W 8i30 a.m. 1 Midnight: shift "A" R0 relieved by day shift "A"_R0.;, d , m'% '

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. ,' Bypass valves are recognized es being open ,tsy7, .B"JR0s ~ J ' ' h ,.9. , 4 '8:33 a.m. ~ .j . ; ., r' . , J, , a1 ' performing panel.walkdowns as part of theirtshifth 'p ,i , " o c? , , .;, ; turnover.'

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> b .u g. ' ' , . i 8:35 a.m. ' Generator load-set 'is' raised to 520 MWe by, midnight ? ' r ~ "' -6 v.

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. shift "A" R0. 7 .- Ec? s + ' ' " 3 4 ve e <p .; , i 8:36 a.m. Bypass valves all fully closed. Generator. load hab, u d $.]p; 4: ' L. increased to 300 MWe. SS directed that DETARS! records be ', . ' . N 5 <e checked to determine if. control rods were) withdrawn while% / ,stt the bypass valves were open. , y ,e _ % ' ' s. o4 , .s, < Cx ".

10:00 a.m.

GETARS records-indicated that control ro%s w*efe , NJ ^ ,M y , withdrawn with bypass-valves open. Initial, notification.

, % of event was made by operations' department to station: ! ' m '; management and.NRC. 9 i 3 . 4:00 p.m. Critique conductedLon the' event by operations , department management. - ., April 12, 1990' 1:00 to Licensee station and corporate management' met with- 4:00 p.m. NRC Region III managers for a routine meeting, at. a

which the NRC exp.ressed concern over the event on ~ ' 1 April.11. . , ,

April 13, 1990 4i -7:34 p;m. Licensee management directed that the unit be taken to cold shutdown (Operational Condition 4). , ' .9:42 p.m. Generator was taken off-line. . April'14, 1990' ~ ' 6:40'a.m. Reactor-was taken subcritical, , w< , v I i y s " '4 . ) , _ _ [ <

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, s,' 5:45 a.m.: ? Unit reached cold shutdown. M> " , , ~ , lM'% g' . .L.>,

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q, ,Q ', 5. ', Evalirdtion and" Analysis " o 41

+n m 0perhtions'ProcedureCP$lNob3004'01,"$rbineStartUpand' Generator, ~3 bp - x %; n

r ' m , , MV 2 T9 ' . Y LSynchronization," was an integrated operating'procedur'e1which 'pfovided

1 > ti', .j r Joverallidirection to<take the unit (from.8% power with' the. turbine ~ ~ ~ gs 1 'W,V .. shutdown and steam flowing 3hr6bgh'the bypass, valves'toL35% power # " - 7' M t , ' withitho generator sy@onized~andLthe bypas' valve (closed.1Thist s ,u. . rA , procedure was being,tailized by the operatorsLatithe time of the^ event. Paragraph 6.8,L Limitations, stated, "In accordanc'e swith TechiSpec 4.1.,4~1, 0 ( l 3- . when 'above 20% thermal power (Low? Power Setpoint of the2RPCS)l,' and when; , J ' ' ~j w the main turbine bypass valves are nottfully closed, control ~ rod; i ( withdrawal shall be preventsd.' This. requirement shall be verifisd by , - V i a sec6nd licensed operator c'r other technically qualified member of. the' d 1 unit technicalistaff and documented by.shif t supervisor log entry." ' - , ' . ' Paragraph <8.2.5' dealt with Generator Synchronization.? Paragraph 8.2.L.5 . g' y' synchronized the generator and Paragraph?8.2.5.6 directed that generator

r ~ load be increased by selecting 4IL' CREASE on the M ed Selector until the 1 _' . bypass ~ valves'are shut,and LoadJSelector is app m .mately 150'MWe above d

' generator: load.' Immediately'before Paragraph 8.2.5.7 was a: caution which! '

stated, " NOTE, Load ^ Selector should be maintained approximately 200.MWe - '

'y- >= 'above generato'r load'for further load increases." - ' o g (

' The "A" R0fwas withdrawing control rods and failed to raie th, load -selec, tor as required by Procedure 3004.01;J c6nsequently,,as n..; tor power .. Os andreactorpressureincreased,themainfturbinebypassValvesbeganto j . Thi.s fact was not noted by either the'"A" R0:or the STA who was 1 open. , D . , performingithe independent verific'ation' oficontrol rod movements. J , , y . There were! multiple ihdications,;within easy view of the "A" R0 and ,'y y - the ~ STA~,L which indicated that the) bypass ' valves were beginning to open.. . - 0

However,

there were,noiannunciators,which alarm when the bypass valves'y

' < were open. With'the' bypa'ss valves opening,- generator load did not j , , s %, . increase. * The STA did observe that generator loar' * <not' increasing. > 4 , . f cTwicelhe > questioned the "A" R0_ about' this . problem 'e "A" R0'did not1 , , 1believe t1s indications an~d attributed this to tha pa ibility that:the,

1 , ,' ' . , . display controlfsystem (DCS)-hadnocked up)(was r.. ,.cating) o.rlthat " ' ,, fm because xenon Was > building'in '(increasing) the " relative worth .of-' control rods /was' reduced; consequently, generator load might not increase. The N - , i "A" R0 continued.to withdraw control rods, i n ' w s > 4 -- - ~ j. e

. . , ,

Administrativ'e Procedurd CPS No.#1001.051, " Authorities and fesponsibilities ' , . of' Reactor Operators for Safe Operation and Shutdown,". Paragraph 8.1.3.1, ' J. v < 7 ,' states "The line Assistant Shift Supervisor: assigned to the Main .- , V.3 Control Room Area shall perform the following ~duti' .s:. a.)~ Monitor f f l ' e Nb ,' , , 'overall Unit operations for adherence to CPS TechnicalcSpecifications. ~ 1 O . . . f.) Monitor CRTs; indicators, annunciators,- and recorders in order

^ . . o ff ' to detect unusual or abnormal trends and' initiate mppro'priate,: timely . ! i" action to' correct or mitigate'the situation.7 The. LASS failed to 1 " . . ,. y ' . / c 3 ., 'y -i p\\ , / ' ' . , O i 4 y + n < ,

8

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h [ 'h, " k,'Y % @- ,4 ' ' ' ' , 77 Jf f ['N f N ^ y f

1. '

' " , - + a : . .. . . . . fgg V 3 f ^ y ;c t -adequately follow;the oversight 1 requirements' of this: proc 5dtNe b x ~ , 0yh , ' , a

4

'he was planningLthe work for the dayshift. Indications of reactor power, - , g. d r . generator lo'ad and bypass' valve. position;were readily,availableLto.him and* . #'.< ' g ^i ~ located only a~few' feet in9 front of his ' desk. - ' e ,- ' ' ' ' - 7. . ,1 i Administrative ProcedurelPS No.1401.01,1 " Conduct of" Operations," . ' " r 'M;>m : Paragraph 8.5,4.2 stateds '! Indications aresprovided 't' monitor plant g ' parameters and.shall be believed,- unless verified faulty'by two-alternate -,'s > o , i%p ,, indegendentmeanstwhenpossible,orthroughmaintenancetroubleshooting."' ' ~ W LThe .A" R0 failed,to.followithisiprocedure,and didLnot believe hi's' ( ' ' .Qw A indications. .The STA still' had concerns with the fact'that generator, . . J " < , , 7g a load:was not going up; however, he'did notiraise these concerns >with thel , , ', , 31- LASS (control room"tupervisor (SRO)).r NorsdidLthe "A" R0 inform'the LASS -. % oftheabnormal;plantresponse6 ,

' , . d , As a result of these actions',It approximatelh 7:38 a.m.f bypass valves. ' ^ s , , 'g began -to open; : During,the next 9 minutes 14-17 c,ontrol rod withdrawals

were perforned. Several differentl control rods were withdrawn, in the; , , , 4- gang mode,:using single notch withdrawal, ,By 7:47 a.m., reactor power ' . had reached.135% and control ' rod withdrawals were stopped, pending startup; ', ,x . s of balance-of plant equipment. Bypass valves! remained open for an , g' additional 49 minutes-(total of 58 minutes opan). c t . . y

,

The main turbine" control valves opened in' response.to increased. reactor % ' ,; ~ w pressure, as reactor power was-increased; this permitted the control ~ ~ ' l '. valves: to" pass more steam and ' increase generator load. 'If' reactor' ' pressure was increased and generator: load was limited, then the reactor- _ ' pressure controller would cause the main turbine bypass valves to:open. j c ' . .c' 1There;are.six hydraulically operated bypass valves. Each has a capacity , Lj' equi. valent' to 6% of ' rated; steam, flow. When the control rod withdrawals ~ wereistopped, reactor power was;approximately 35%. - Nominallyp 26% of :the '1 . - steam flow (reactor power) was going to' th~e main turbine; the other.9% , , was going.through~the turbine bypass?valvest The reactor did not.' sense ,1 - 'y ^ _anything dif;ferent than if all 35% of the steam flow had been going to

' c g the turbine. However, thisycondition was significant because the! rod 4 > ' - ,s . pattern control systemj(RPCS)' utilized main' turbine first stage? impulse

< pressure as an inputMFirst stage? impulse pre'ssure was-utilized asta . ., linea'r. method of measuring equivalent reactor ., Consequent.ly,'with # s'meLof the ste'am flow diverted from the' main, power. turbine,s the first stage. 7 7

'

' w o - . impulse pressure sindicated a lower -than actual reactor power. The RPCS f , ' - ~ t , -usedgthis edui/alent reactor power to limit' the number of potches a' i, ~ e ". ' - - control rod could be withdrawn continuously. J 4 , p ~

[ Technical Specificationf3.1.4.1 required that control rods shall'notfb'e. 4 J

withdrawn in OPERATIONAL' CONDITIONS 1 and 2,4when the main turbine bypass

. ~ ' ' h ?e 'v'alves were. not' fully closed and' THERMAL POWER was' greater than'the lo t R "i_r . power setpo. int of.the RPCS. With any control' rod withdrawal when the

main turbine bypass ~ valves weresnot fully closed and THERMAL POWER was- , greater.than the low power setpoint of the' RPCS -IMMEDIATELY (emphasis >T L '

f added) return the control rod (s) to the position p~rior to controit rod i ,L L, Swithdrawal. Technical.. Specification Surveillance 41.9.1. required that ' Ucontrol rod' withdrawal shall.be prevented when the main turbine bypass - n[ ^ fvalves were.not fully closed and THERMAL POWER was greater lthan.the. low + ^ p"y (> } . . . 'N I ' I '5 d

' ' 7 z, . - 1 ,, J - i 4 ' ' A .a - .l ' F + -

'k(QQQl pg o L ' ; } t g;y c-g j f Q L ?-Y f ," w pgh g v3 % ' Q$.Nf% V gn : ~ A ;% 4, y . W d 'a % , ~- ,' %) ' , M %; % M ' , 3 y, .. _ , ' 3,f,J,. ,,_ . + , q'* h , y,p y,yp> r , , ' 4 g ;gML ~ vn ? / - - g;%jN{M ,' ' power setpoinEofithe' RPCS, b - a second.lic'ensed operator or other. ~;

!j C

technically qualified member of the. unit technicals staff.. ' , , , .. y4 > w4 .a

. ~ 4"Q [)TheJbasidforl Technical" Specifications 3.1.'4.1:aad 4.1.4f1 stated t ' '

3 the' rod withdrawal, limiter system input power signal. originated from.the mairi turbine first stager impulse pressure. When operated with'the: steam j - . PWM bypass jalves open; thisfsignal' indicated a core power level lwhich was 4 %i>- . less;than_the true core power.. Consequently,;near..the , low powerisetpoint- A @ 4:and high'-power setpoint ofctheirod pattern control; system, the potential d H , . ' ' 9 existed for nonconservative control . rod withdrawals. ' Therefore, when , ' k*k . operating 'at a .sufficiently high power level, there was'a 'small probability' Ol ~ [ .

of' violating fuel Safet) Limits 'during a licensing' basis. rod withdrawal

l 1, error transient. To' ensure'that iuel Safety; Limits were'not violated, ' ' - b% , m . . this. specification' prohibited control rod withdrawal when 'a biased power > b X/;

signal existed and core power exceeded:the specified level. - m. uwu I ' / !Theactual_safetycconse'quencestofthereactorcoreNeremitigatedbythe ' , < , ,y fact that all of ithe. control rod wit _hdrawals' made'by th'e ;"A" R0 during ' gh i -this; event werelin the propertsequence'and were< single notch withdrawals; ) 'vice,'the fourinotch withdrawal limit which the RPCSLwould' impose from ' <

4 25-35L power.;sConsequently, a'second' independent error, plus a much: . i $: H " ' higher reactor power level would have'been necessary to challenge the' , ? 1

C

jfuel safety limits; 1 ' h, . . f .At~approximately 8:20 a.m., the midnight shift "A" R0 and the day shift ' 't ' ' > , ' l'A'h R0 ; began theiroturnover. Both.R0s stated that they had stopped at y% 'the panels which contained at least- six separate indicat_ ions that; bypass- t s Gb' , . valves' were open snd discussed _ the st' tus of- the equipment * contsined on ' a %s those panels without' recognizing that the bypass valvesi 4re open.. The' ' 6_ ~4 < ~"A"iR0s; completed their turnover, at 8:25 a.mi, The :"B" ws were , j -

' - C y *_ performing their turnover and'at-8:35fa.m. the day shift "B" R0:disco q %

the bypass;valvesio' pen, After a<brief discussion sthe^ midnight shi.ft " "A".R0 then'reised the load set, which caused the_ime'did'the4operatorsgenerato '~ - d j yW i p ,4cM increase:and the bypass valves'toiclose. At no-t D r , V.e 'e 7efer 't"o the the Technical Specifications to verify that allireq!uired " actions 7had been' taken. N/R 4: < ,. , , n .my 4 w< ' ,The action statemerit' hf Technical SpecificatioM3:1.4i.ljrequired that s D, [2, - , - .

/

with-any; control rod-withdrawal, above the applicable power levels;and " - 3 pf any bypass valves open,'IMMEDIATELY-.(emphasissadded) return the' control n" s

Technical Specificv ion _ action statement or change plant conditions; such,-

jl rod (s) -to: their priorsposition. Typically, licensees may complyrwith a- e

+-

1. .

n- . , ttnat the Techeical Specification is no longer-applicable._. When the R0sL +1 ' , .. %g' 'discoveret the bypass valves open,'they raised 10ad-setcrather than? q~ ; inserting' control rods. ?During the interviews #sthe3 g;' ' _ 3 . . fl , the; operators stated that? % a+.' when;they discovered!the bypass valves open they did.not believe that r - ' , E controp rod withdrawals 1had causedxthe bypass valves'to come'open, but ' b - , that'some unrelated problem with the bypass valves -had occurred. :The 7 operat' ors remembered the procedure requirement to keep ~1oad set 200 MWe ~ , E which' generator load and with--no-nexus to the control rod withdrawals above A ..

haa bopermd i - ar, they raised tFe load set. However, ' o &: t Ethat-is not <at t' >$ ification action statement required. ' 'O' l , , . 5 t: f, , i. - - < 7,b 10 . , m ,

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& . , , . , 5 . ._ . ,A . . , I ' * ,^ 1 During the interviews, allithe _ control room personnel stat'ed they were 7$ g >> , , f amiliar with.the prohibi. tion against withdrawing; control l rods,twith ' " ' . , r ' [ jthe' bypass _valvesopen;'however,theywerenotfamiliar.withithe. . ' '; N , requirements of_the immediatelyJeffective action statement to insert' s-

" . o control rodsr They.did state . . and saw a bypass. valve come;oplthat if they,were withdrawing contro14 rods g~ m en that they wquid immediately insert-the '4

+

@

i control ro' ds.; C " , The inspectors discussed the intent of the action statement with thd,NRR * .s.

...

i ,m

. . . . . " f ' M, 3 ; staff, fin this' event, raising the load ~ set (so that the-RPCS-would'more- t , i / Laccurately knowsthe' reactor power) was not technica11piincorrect or' o a , u 'i' v - unsafe. Nevertheless, the action statement was based' upon the' supposition 1 i poj that a rod withdraw'ai error had occurred and:that fuel: safety limits had + R .'been, or would; shortly- be, challenged; consequently, 'to~ minimize any fuel ^ 7 , g damage the controlerods should be inserted to, reduce the power density * ! ' , , [ dnd=enthalpy of'the fuel as soon as possible. ' a: t - n . , - y fP Procedure 1401.01, Paragraph:8,5.4.4"sta'ted, "Other permanently installed

p indicators (gages, meters,srecorders, etc.) that are" removed from service + a ' '. or . operating in a. degraded or out of< calibration status,'should be. N . < 1 'ident.ified withia yellow caution tag." There were no caution tags.

A#c . s f on' the load , set- meter or. load selector. pushbuttons.

• i

'j ' T , Y6 Durihg!the int'erviews with the contirol room crews a d~ the' trainin~g . . 'I n - " ' . department, several related facts emerged. The modeling of the simulator J- '@ with regard to'the difference between the load set and generator load.was aj not . identical /to'the actu'al plant. 'As-originally designed the. difference ! 3 B' ' between the load and load set was,less'than-501MWe; however, the meters a < ' _'p in thefplant did not respond that"way, cPer Procedure" CPS No. 1401'.01,.. y- , ' Paragraph.8.5.4.4, a' caution tag was previously placed on the metersjing ,; the control room to indicate that bypass valves would.open if load settwas

1. ,

- ed

not more than 150.MWe above generator load.

A modification was proposed ' > Enot~ approve thel problem; however,':the modification review committee did-

to correct'this.

3 ! o U* change as being cost effective and.a decision was made 4 . '. ' to chang ~e the' procedure .to reflect the greater difference 'between load ' t , ~ , "y . and load set by incorporating'a cautionary note; which then allowed the- ' caution 1 tag to;be removed. The training department.was not informed of' l ' K -the decision of the' modification review commit'ee and consequently did 4 s , not realize that'the' simulator did not accurately ^model the plant. '

> [m. '

Statsments were madeit'o the insp dtors;that someicontrol room personnel

m ' e i had.. felt they'were under; pressure to.get to 35% power and that.they did

' -not want to continue'with the rod withdrawals during the turnover process; N ; 6 mE howeverf when directed ~to proceed they'did so. .The oncoming'SS(was - 4S' Leoncerned with the' continuing rod withdrawals and discussed-this concern c' s 'V with the' LASS.) Before.a decision to stop the rod withdrawals was made, w 4 35% power was reached. , j "

, , ,

w W^ Y , .V review of integrated operating procedure 3005.01, " Unit Power Changes," ~ ' l which was used to take' the unit from'.35% to 100% power, indicated that Of ' ( ,

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' ' ' a 4( v % ['the procedure;did not~contain any references to raising;the load s'et, d ,. o. n y; - E u n ctor-power was increased.- in - ,

q

~.

y + < . .. Y 16b zi.icense'e's Corrective Actions * . ' , .. , , 'l ~ ^ ' , , . ~ ;; . < - . ' .

T ?

In? response to the event, the'-licensee , implemented,the following"

, ,E ' Tib m - corre:tive actions: ~ '

, , , ya . . >

. , ,- . ' FV. 'a.: Each shift crew was briefed on the event anduits causes before ?' "- > . f ' "' , they came on shift.' 6'

~ ' t , , &. .- . . i " ? b .- ' Each shift crew received retraining on reactivity management >- v' proceduresi thelimportancesof procedure compliance, and the ,. ' . , importance ~ of -close monitoring of equipment configuration and

, .f'" thorough equipment'. status. checks during.shifteturnovers; The ' M, crews were also ~ required to perfonn exercises on~the plant simulator.

to assure that they fully understood the! proper checks:and procedures. , . . 'to follow duping' reactivity changes and-plant:startup; Each crew ' swas required.to> complete.a written; examination covering these

5

. topics. t , > s - , , ThePlapt' Manager'andVicejPresident-metper'sonallywitheachshiEt' c. crew'to discuss the causes of the event and to reinforce the lessons ! ' 1, prbsented in'the training described above. - . Ld. TheLVicePresidentmet'wIththeClintonPowerStation(CPS) -i ~ . ma'nagers and-directors to discuss with them the;importance of pro _mpt , , . ' ~ recognition.and response to potential problems, Land prompt reporting / ' ,. - of.these problems,up the chain of: command. ' . n- Je. An experienced senior-level incividual,ireporting directly to: ., the Vice-President was-a: signed to monitor Operations department performance to provide additional 2 assurance.that significant- , problems;would be.pfomptly. recognized and responded.to. > ,, f. - Eight director-level individuals were assigned to monitor power ascension. These individuals. monitored each shift's performance. ~ until the, plant attained full po'er during the startup' subsequent w ' ~ to the event. ' g. Experienced' personnel, reporting'directly to the Vice President,' ' ' from outside'lllinois Power (IP)=(one from Stone and Webster and' ' > % two from Toledo Edison), were retainedtto independently review- the cause of the event and the licensee's corrective actions' . ~) 0

~ . ,, . L 2 h.- The licensee changed its: policy so that'no significant evol_utio_ns would occur during shift turnover. If necessary, the shift turnov'er i . j would be delayed *to. allow continuation.of a critical evolution;that- 1 ' '

' > M - , .could not be stopped at that. time. 'The' plant would be placed in'a . R stable condition prior to turnover. a '

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' ' ~ .' iE t (%it 'The, power ascension'procidure i. . , .. , u 3004.017wasJchanged.t5requirethe.,,o y ., N t. g g v ,- .. b op'erator tocincrease; generator load set to a pre determined level p ' r h .l - ' in a plateau method'.asireactor-power is increased. The' pre determined 1' ' i ~ ' , - 5 q 4" w +, levelLwas_specified!atlappropri_atelparts of4the' procedure., And at!' & < 1 v1 ,wasiraised to its' maximum value at.the end,ofa3004.01. ~J ' s 's. o , ,s h~? .11 ") l, ,s .r

$. . , , . .; . . . <$ ^ ' @M4 ,-j.i . Aolabel;was added /by?the' generiator loadEset meter on. the standbn ' .* - ' ,* . information~ panel and by the generator ^1oad' set increase'and decrease ': ?# [

f100 MWe high..Je v i # o b ' generator l load < set-meter: read" * push buttons to annotate that3the: ~ > , " 7 y n 5 .s , ., mp 9m + - i o ' <

. ' _ . .. . & kJ The-generat'oriload set meter iincthe simulator was adjust 5d .to) ' J

, 5 m > - $ 4,. Ereflect the actual control. roonFcondition of reading,100 MWe high.. , m ' % s 1

. . ~

o a s. .. ., , . f " il,, The-trainingdepartmentc'ompletediabeview~ofdisapproved_. [," , %

modifications, to ensure that they did'not result in; procedure -

o' 44

changes which would affect:the' simulator modeling(

• m

1 . ~ y , , m.- Integrated operating proceduresfwere. changed to prohibitfthe LASS ora e y . + d4 the STA ,fromifunctioning astindependent verifier. This' allowed them

^ , Ig g to step back~and_ view the whole plant. - ' - fe 3 ~ 7. .0bservationJof Restart , c L" '

.

m p " , , 'At the direction of Region III management, inspectors were; assigned to; a - augmented coverage of~prestartup,1startup, and power' ascension activities, to;approximatelys35% power. Areas that were observed were as follows:

5 ' ' c . m a..SRequiredsystemswereoperable, ' ' ,. -

' _ v - .. 3 '~ . b. Plant > operating staff was. ready,. y s' '# ' , . . .. L ,g A f Minimum. number ~of problems / alarms;in the-control' room, ,

< r- cc , < , < m , . , q, . - a s , . J d; Control room' procedures were current, ' ,s .. , . , . . , . , f' 1 e. Adequate preshift' briefings; occurred," [ > s , , - ( s 4 4 f.

Inter

and intra shif t communications were adeq'uate,

, , , , .L .. , . - " . . .' . , '

h3 g. L0perator responsiveness to alarms and cont.rol room . a ,

n 49 ' indications were correct, and . f F> <'

. ,- . y> s / %' he Lo'g keeping practices were acceptable. 1 g N a. s . " W e inspectors; observed control room actikities from April 22-26,D1990. -

The overall perception.wassthat allioperating personnel performed in an; [* ' , fs < extremely t.onservative and safe manner. Ongoing gevolutions~ were stopped . ' - , W ,well1before shiftiturnover would b' gin.HThe preshift brief.ings were e

l} h':e _>,. thorough and' detailed. During thelstartup.some of the' operators

• Aw

thorough,and detailed. The turnovers.anJ>walkdowns were also very ' ' "s p, were observed to be very nervous l but'they becamefmore confident- 9 a s y , i '

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as the startup progressed.p,Ther'e.waslno sense of* urgency to ac'complish

' m 7 - c c @ y < Operator performance,of-gontrol . rod;wi.thdrawals~ andcm6nitobing of the ' Ml c 3m n too many' tasks",.butia recogniti6n of the need;for controlled progress. C' > > ' - . , . u. ,,lant! s- responsd'wereio' arv'ed to be :very good.- Control of personnel and [ c4 & restriction of work activities.during the:startup were good. 'A sign was 'l

' < - 'n,M . . t f p'ostedilimiting controloroom access 'during thelstartup. .. Control rod < - . A , movements were' monitored'forrcompliance withTechnicalnSpecifi ; ons ' Qt 'and the planneri rod pull sheets. "There were rio discrepancies . .his ^ .- area. The inspectors ;did note that'some of: the LASSs would focus too; ' , hk , closely on th'e,680 ('re' actor control) panel activities- and not step back . ' S ' ' d' and'look a't the whole plant',1 ut this was' isolated to one or 'two . b . ] Eindividuals;and they were improving as the startup progressed.

, i- . 8r _ , n > o g

. ' - Q, %_ Q ^ ! Conclusions > a R 1 ' 3 >; r; , , . W "The inspec'brs have;idsntified-the following root causes for this eventi

G r . . - v , The"A"R0_fWeb(tOfol'lowproceduret'o,raiseload'setashewas!

ft 6

4 ~ %' as - increasing" power,;by; withdrawing control rods. , . , ," '._ N.. w , ' -b;' The "A":R0!and the STA did not monitor bypas's valve' position - af_ter the withdrawal ofscontrol rods. ' '

' ! &

. . . The 'A'I R0 did not belih his indic$tions when told twice l y? ye, ' i ~ ~ by the STA:that-genera' a load;was not. increasing. i ' , , ( ,?dalTheSTA;andthe-"A"R0didnotidentify:theprNblemwithgenerator' , load ~.to the LASS.- > x > , ,g n . ~. '. p* - -

1. .

. , , n ie.> TheSTAfdidnotpursuehisEuoncernswiththeLASS:aftertheanswer- 1 ^ %~ ~ he was given.by!the "A"'R0 did not seem right.- i ' _ 3.- ' q. _ m' . 1; v .. . ~ . '- - . ., ' . i fi The' LASS [ failed to adequately monitor overall unit operations by; ' 4 i observ;ing plant indicators.' ~ h , n. - +, . j "4 ' 7TheLinspectors:have identified the following contributing causes ' ' - ,s -forlthis' event: f'

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< g .- - < ,, , , ',A poob human 1 factors approach in the integratedioperating procedure, ' regardinMraisingdthe load set continuously, as directed by, a.riote',_ 4 W a versuscdiscrete' procedural steps and rai_ sing load set to discrete j nW plateaus. '+ e', '3 ~ 1 p, ,; ,! f= , , , FW 3 h., ' Pressure on~th'e' midnight shift personnel ~to get to 35% power. {E t

m Q. . NG" ' Performing complex evolutions during,turnoveri jg ,Z ' , , , N'... i; TheE"A'l R0 had only done this7 portion of a(stMtup once;before; and p $ ,. w

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, . J A ,m Thad-only done a total of ta xe startups 1This type of" activity was'

, , WM typically not practiced ont he simulator.i. Hoyeve'r,' this operating:

t r?' crew'had,been given practice on the simulator,.within a month of - x ., ' \\ u < ~ ', *y l h- 4 .; , , , 7i ~ i 4 r , , en\\ 'V

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b,i this eventF on reactor. s.tartups;' but due to time' constraints, certaini O;% ' ~ m portions' of the;startup., process were ski' pedi. ' ' ? ' ~ p ' ' . > a , ! ' ,. W Jll W - - c g . . . , 'j1 Nolannunc~iatorialarni for open 6ypass ' valves existedi S x- + . s - , . g' ,/ *.,' ky /The wording of Technical > Specification 3.i 4.1 and , , o . . . . . . . . . , ' ' ' f Surveillance 4.1.4.1 was cumbersome and~ awkward. 0The~ wording was' 6 ' ~ - 7n,, - j%/ copiedsintorthe operating procedures. ' q W . ,

+ c 4 .. L .> . 3' ' , D, 2 cThe simblator did- not niodel plant performan'ce on the' response Aj , P' 'of load set versus generator 1oad.. accurately., Training was nit #' '9 e >s, informed of rejection-of a~ modification and the decision to' sM W G N , ? " utilizea procedure change to correct.a problemc . Consequently:, ',;g d ' fg !the>simulato" was not updated'from the originil; design' basis. , -

a ,- - < e- w , , P m. The lack of understanding'by the,STA and the "A"'R0 that'a xenon , transient would not have a significant affect on reactor power over - ] a'10. minute period. ' y)9 + ~ , .. . . . ..

• .

The actual physical: safety significance of'this event on the reactor d ~ r/ . core was minor,because all of the control rod withdrawals made during 1 ~ m ' this event were 'in :accordance with'the rod pattern' and were Lat a rhte - c ? ' t - m (single notch; withdrawal vs. four notch continuous' withdrawal)~which. d > 4 was more c'onservative than the. rod pattern controlEsystem limits. .A.,

j

4 , . ~ . , . . . , ' . p5' The safety significance of :this event is derived-fromMe lack of ' . attention-to plantiindications during important' evolutions by 1.icensed? 1 s , personnel, not b~elieving plant' indication's, not' informing supervisors of. , . unexp:: ted plant response,1 and the scheduling. and controlling of . complex d, - , i f .;'and safety significant~evolutionsiduring shift turnovers." fj ^ r

.. s ., 4 .., ' 'This event and-two other recedt' events involving (operation'sSdepartment ' w l , ' personnel (the cracking of condenser. water boxes..and the4de; energization' ,; " ^ , Gof the Division II NSPS bus);taken together,were not;icomme v . . 4 ~ indicative of i + 'W, M adequate performance fAllrthree'of these' events had i ' t- e' , g ~ s$# involv,ing:- adherence to procedures, commuhication Detween c.g .

crew members, turnoverJof information between operating crews, -d. 6 A, e , management oversig't and direction:of. operating crews. . '

1 " n . , ' Technical . Specification' 3.1;4'1 required that control' rods shall not f, d ' L ' >be; withdrawn in OPERATIONAL CONDITIONS 1 and 2, when the~ mairioturbine ? , . ' bypass valses.are not fully closed and: THERMAL-POWER is: greater than .

' ,the low power setpoint of the-rod' pattern. control' system'(RPCS). The . N action statement required ~thatSwith any control rod withdrawah when the' , . main turbine bypassJvalves are not/ fully closed and THERMAL POWER is i ! P" % @ greater than theflow power setpoint of'the RPCS,eimmediately return,the. 76'1 ~ ~ . ' . control rod (s) to the position p'rior to control; rod withdrawal. , y . , , , d TeEnnical Specification Survejilance.4.1.4.1 required that control'. rod ? twithdrawal'shall'be prevented when the main turbine bypass valves are not l y , d fully closed and THERMAL POWER..is greater than the low power setpoint of iv.

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- ' - w . . g j' % j y - , , y; s . o , > _e s -W -r* g_ .}Y, g#y y ' , ' M [[4 $y' y < , , 1 . l; theiRPCS,fby a,second< licensed operator or oth @ technically quklified g meinber oflthe unit technical" staff. f' ' , ,3 MWith the reactorlin OPERATIONAL ChNDITION'1 at asthe mal po er $bove n

' A ' - StMthellow power setpointiof the RPCS,14-17 control rod withdrawals 1 1 ' were. performed by a reactor operator,3with' main; turbine-bypacs; valves not y) 1 ' , %j', ' fully closed. Upon discovery.Lofsthe open main turbine bypass; valves,tthe- 4 / 4

' @_

, . load; selector ,was raised 1to c'Me the main t'urbine Ebypass ' valves;l vice; ~ s ,_ insert!ng contr::1. rods. Mhe withdrawal of contro]frods-with the. bypass, A / v' . AWN valves Jopen is an: example of an apparentViolation .of! Technical: ~ ri "' S '@ . Specification 3.1.4.1 (461/90009-01a(DRP))~. !The failure of a'second- 3 ,,M i L - " technically qualified member of the1 unit technical. staff to~ prevent- ,J ,; 1 , N control rod withdrawals, withl main turbine bypassivalves not fui > closed,c M " > -1s an example of fan apparent violation: of Technical Specificat' ion 4;1:4.1 'M , , $p , , ,461/90009-01b(ORP)). - g ( ,

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/10 CFR.Part 50[ Appendix:B, Criterion Vk required _that'act'ivities'af fecting- / , 4 qualityshallbe=prescribedbydocumented: instructions-oriprocedureslofia .- j

• ype; appropriate to'.the' circumstances and shall,be. accomplished in

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y . , f:' accordance with'those2 instructions.:

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' 3; , . , , " " 1 Clinton; Power Station Operations Procedure CPS No. 3004;01, " Turbine ?Startup,and Generator S.ynchronization," Revision 12, Paragraph 6,8, ' '$ . " Limitations," stated, "In accordance with Tech Spec 4 1.4.1,lwhencabove' , 20% thermal power (Low Power Setpoint o? the RPPS),:and when the, main ' - turbine bypass. valves are not. fully closed, control: rod withdrawal shall 4

q' , " ~ be prevented; This requirement ~shall-be verified by'aisecond licensed y '. 4 - operator or. other technically cualified member of the unit technical: staf f and' documented.by shift 3upervisor log entry." Paragraph 8.2.5.6 containe'd a note whichitated, " NOTE, Load Selector. should be maintained ' v'. , approximately 200 MWe above' generator 1oad for further load. Increases." y _~ t . . . . . 1 , Clinton Power Station Administrative Procedure CPS No.1401.01',;" Conduct;

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H.of Operations,":Rev'ision'2,' Paragraph 8.5.4.2 stated, " Indications are provided to monitor. plant' parameters and shallibe believed! unless ," verified faulty by two alternate' independent means when possible, or' > < ag' . - through. maintenance trouble shooting." ' Paragraph 8.5.4.4' stated, "Other ' ' permanently installed-indicators (gages, meters, recorders,-etc.) that

are removed from service or operating in a degraded or,out of calibratioln

J , . , status, should be identified with' a ye!10w caution; tas" -4 ^ , e~ 4 Clinton Power Station Operations Procedure CPS N$,^3005.01, " Unit Power R Changes,'? Revision 12, provided detailed instructions for performing: i , c tho operations required to effect unit power changes between 35% and i .100% power. i Clinton Power Station Administrative Procedure CPS No. 1001.05, Y " Authorities and Responsibilities 07 Reactor Operators forfSafe Operation and Shutdown," Revision 6, Paragraph 8.1.3.1, states "The line Assistant 3; " < s '

Shift Supervisor assigned to the' Main Control Room'Are shall' perform the

' -following duties: a)' Monitor overall Unit operations 1 adherence to 4 ,' CPS fechnical Sped fications. . . f) Monitor CRT's, indicators, . , , ' , 1 d- 16 < < ' .. , ' c g

7 y + - w. , , _ , , 9 ' ~~ o ., , . . . , , , , ( A fg' j n=g , w

- &b: Q ' ' + . 7 - . + ' ' " ff (" 9 * . . . . . , . g ' ' , . annunciators',?and recorders,-in order to ' detect unusua1 Tor abnormal M trends', and initiate appropriate, timely ~ action to correct or mitigate ' , the situation." ' s ' x , - , ' , - The following are'all examples of an' apparent' violation of 10 CFR ' ' Part 50,7 Appendix B, Criterion V- 1 . , ' The "A" R0' failed to raise the l'oad set whilefiricreasing reactori . .I e a. 4 power to keep the, load set 200.MWe:above' generator. load,'as' requfre'd O O i{ i ,J %f .g 'by Procedure'3004.01 (461/90009-02a(DRP)). ?i " ,' - , .. _ ( b. 7 The "A"' R0 did. not prevent the, witt.drawalfof: control- rods with: the .- . - s j , ' main turbine bypass-valves not fully closed and reactor power. above t.d - v , the LPSP;as' required oy Procedure 3004.01-(461/90009-02b(DRP)). d' ! > psx . , Is - I ?/* $p. l 4 ,,~c. JThe STA did not verif'y that-control rod withdrawals wereJnot 1 1+1 <7 ,g.- , 4~ . .. . , . j - (l ~j s g ' ~ % Y_ [ permitted.withithe main turbine bypass valves not fully: closed;' 'h. i andreactor. power.abovetheLPSP,esrequiredby" Procedure >3004.01], t %' M Vi4gw c j , ,$. (461/90009-02c(DRP)). W g(1 l . j o d. . m ., , , f * *O N a! ~ s 1R. ; ' v+ % > t , M, Thei"A" R0 did!not' believe hisr indic'ations when he .

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df ' that generator load (MWe) was not increasing. He did not verify - M h.A 'through other'available indications that generat'or load was. . ' ' y 9,'4 ja <

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, , respor. ding correctly, as required by Procedure' 1401.01 ' " W f' -c(461/90009-02d(ORP)).- , , ' g(.) sc,, 1 y '5 . r o- s. . Nocautiontagwasplacedonthegeneratorloadisetmdter;

' 3 ' _ e. e 'm. "9- located on the standby inf ormation panel, to indicate'that'; . . . - . s %' o it was,in a degraded condition, as required by Procedure 1401.01 f t , ' W' -(461/90009-02e(DRP)). ' m o O f. ' Procedure 3005.01 did nottcontain any instructions for raising the: S load selector, cven though:this= action was required to raise unit . Jpower from 35%'to 100% (461/90009-02f(DRP)). , ,- ', J J ' g. !The LASS ' failed to adequately monitorf overall _ unit operation by not' i observing . plant indicators and therefore did n'ot" detect that control' 3 rods were being withdrawn with the bypass' valves;open,?that. n generator load set was not being increased,~and'that reactor power ~ 1 was increasing-without a corresponding increase in generator lo&d. a" Twogpparent violations neve identified.

s. g .u v . , ' ' 9. , Recommendations < l x a [The'inspectorshavemadethefollowingrecommendationsforthelicensee's ' A U - '[ Land the NRC, management's review:

q

' , !ar The licensee should evaluate the installation of an am1unciator for - ' i open bypass valves e en reactor power is above the RPOS low pmer. T < [ - setpoint. i

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q .,1_ . , ,q . { ' T' . * '~ 1 v . , . 3 j. u , @J NRR.and theilicensee or~the;BWR-6:ownersigroup:should reviewi T _g l E .n -b. . g the wrding. of? Technical Specification's; 3' L4.1 and 4.1.4l-1, / P " Qg b ^ and determine ,1fj more-: easili Wnderstood + cding >is"possible, '

' g y 3 pg# y - ff this lis"possible 'the inspettors"recomond that the fe~chnical i 7A m f hk "

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^ SpecificationsLfor all BWR-6 reactors be<am,endede - ' .$ 't n -

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. . . s Licensee manag'ement needs t3 continiie einforhing;its philosch.gy of; M- - , c. . _ . g j# t, 4 -

operatio,o,n an id the need for communice' ona,6dpro'ceduralfcomplian'ceu,

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Exit-Interview +(36703)6'? fig ",c ., ce g .,,q- .- . ,, m .. ..,m. s. r- , s . gt, , , o , . .. , , .W

f n ' 4 W .. ~ n,,. .. . . . vg , 1 . +, , ,. , v -j, JM 'keinspectorsFmet5,withthe',licenseerepresentativesdenotedinPiJ ,. ,, t ) - ,4% at the conclusion of;the" inspection on ~ April 27,1990; ectors' P; k;y i ? summarizedLtheDpu'rpose and scope of the inspection and the-findings. . ,u a " $ . @:S *4 , The inspectors 1also discussed the;likely infomtional content of the < ' , ' 's.44 ,oU" theinsp{onieport',iithregardito' documents"or' processes (reviewedby ^ Inrpect C ~l , ectorsiduring' theminspection., The tlicensee Kid not identify - f -) t;p s '

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