ML20086L820

Requests Temporary Waiver of Compliance from TS 3.8.1.1 (AC Sources - Operating) Action a to Allow Plant to Remain in Mode 3 for Up to Seven Days While Troubleshooting Efforts Continue on EDG 1-2

ML20086L820
Person / Time
Site:	Davis Besse
Issue date:	12/06/1991
From:	Shelton D CENTERIOR ENERGY
To:	Davis A NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML20086L802	List: ML20086L820
References
1-967, NUDOCS 9112170092
Download: ML20086L820 (10)

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Docket Number 30-346 t

License Number NPF-3

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Serial Number 1-967 December 6, 1991 L

f Mr. A. D. Davic l4 Ryional At-ini

.trntor i

U.ito: %-t<m !:a :.1 a: h gulr. tory Co-rir. ion Eegion III

]j 79? IWosevelt Road Glen Ellyn, IL 60137

' S, bject:

P,equest For Tuporcry Vaiver of Complience Trom echnicc1

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j Spe.cificetion 3.8.1.1 (AC Sources Opereting) - tion a, Dest Mr. Davitt f-h e purpose of this letter is to request a temporary vaiwr from e t, crpliante with Technical Specifiet. tion (iS) 3.9.1.1 (AC :cutces -

d 9pern t ln;:) Act kn n., to asold putting the Davis.Besse t4utlear Pover Statica (DBNTS) through a thermal transi+ n due to chutk.n tp tequirements (i.e., a cooldovn of the pr ary system fror approxinately 530 degreed T to less then 200 degreen F).

Davis-Besse thelear Power

[p 5tation entered this 72-hour Allovable Outage Time (AGT) 5.ction at 0500 hours0.00579 days <br />0.139 hours <br />8.267196e-4 weeks <br />1.9025e-4 months <br /> on December 3,1991, to perform planned reutine maintenance en

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E-ergeticy Diosal Generator (EDG) 1-2.

The EDG could not be k

succe:ssfully returntd to operabilit/ in the allotted ACT folloving

'l ccr.pletion of naintenance activities. Therefore, as required by

'.h e 1

Action statement, a shutdovn cemenced, and Mode 3 van reached at 1055 i j h ors on December 6.

A temporary valver from compliance with TS 31.1.1 Action a. is requested to allow the plant to remain in Mode 3

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for up to seven days vhile troubleshooting ef for ts continue on EDG 1-2.

}a If EDG 1-2 cAnnot be returned to operable status by the end of seven days fro: the Mode 3 entry, the cooldown to Mode 5 veuld immediately

,}j c monec, vith Mede 5 required to be reachad within tha following 30

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hours.

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Eoquipements For Vhich W -

3jgquested

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Technical Specification 3.9.1.1 (AC Sources - Operating) ACTION a.

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states:

,t Vith either an offsite circuit or diesel generater of the above requirad AC electrical pover sources

,n (including two sv.parate and independent diesel

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generator *) inoperable, desens trate the OPC?J.BILITY of the remaining AC soveces by performing Survaille.nce o112170 % : 3Lt:10 fDH

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.Requiroment 4.8.1.1.1. c wi thin oN hour and at leM t l

once per eignt (R) hours thereafter and by performing

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Survcillance Requirement 4.8.1.1.2.s.4 within 24-hours.

Restore at least two offsite circuits and tvo diesel c

generatots to 0 FEM.BLE status within 72-hours or be in at least MOT STid:DBY vithin the next six (6) hours and f

in COLD SHUTD0N vithin the f olloving 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.

6 The DBNFS vas operating in Hode 1 at full pover on N e w h c 3.

190'., vhen this Action State,ent van entered at 0500 j

i 3 md routine nsints.nte un EM 1-2.

As 1

nrus;.: :, perinr:

described in further dete11 belte. iE 1-2 could not be rete ned to

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eparable ctates vithin 'ha 72-hou: A07.

shutdown connened and hade 3 (Hot Stendby) vas entered at 1054 heurs on Decent >er 2.

In

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accordante with :he Acticn stateu nt, Mcde 5 (Cold shutdovn) entry 1

is pre:ently :equired by l'ik hours on D cerber 7.

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2.

Discussion of Circumstances Surrounding situation f

s:

P On October 21. 1991, EDG l-2 vas started as part cf the SFAS t=

Integrated Response Tine Test.

It failed to develop an output i

veltare.

Subsequent troubleshooting deterrined that a problec existed in the field fle.sh circu!try end var. believed to be I

associated vitt the speed svitch.

The svi ch was replaced and the

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unit was started successfully fcur tices vi th no abnormali ties associated with the speed svitch or field flash ctreuitry.

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On Noveaber 6,1991, during the normally scheduled nur <eiUcace f

test, EOG 1-2 vas obserw!.o take 30 40 seconds to develop rated the nachine voltain. The field ficsh circuitry vas instrumented, shut down and then fast started approximately ten minutes later, The cachine reached rated need and voltage in 7.? seconds (neetins f-k the requirement of less th e 10 sc onds) vith no tbnormalities, k

the field f' lash relay was teated to determine i

On November 19, 1991, The j

if a time related degradation vns affecting its perfornance.

a relay vas observed te u ke e.pproximately one second to pickup, The co pared to approxima m y 20 milliseccnds for a nev relay.

f field finsh relay vts replaced and surveillance testing of E0G i-2 4

vas completed on November 20, 19914 The relay pickup time vas in g

the range of 16-24 milliseconds.

At' 2100 on Decener 3,1991, f olloving planned toutine maintenance 1

idle started vhich began et 0500 on December 3,1991, Ett 1-2 vas but was shut dovn approximately five seconds later due to f ailure I

of 'the air start motors. to atrac t.

Subsequent attenpted starts for troubleshooting purposes vere also unsuccenful.

The symptoc

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of failure was a defective speed svitch.

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sluilu t tica betvoen the syuptoms of the f allute on December i

3 and the ryr.ptoms of pravious failures, an extensive i

troubleshooting campaign van conducted by the Maintennnce, F,ngineering, and Operations organizntions.

In addition, the j

indopendent Safety Engineering (ISE) organfration conducted e i

toparate anc indep*ident investigation in parallel.

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The speed s. itches froe thu October 2) and December 3 failuren vere

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hind-delivered to the ennufacturer and undertent testing en

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5.

The need rv!tch from tha October 21 fr.ilure m p

'im -t re: ; b fe.i?ud due to nm u

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N spee. : i tch f re-d i

te De an h. 3 failure v n dnNrnined to have h.11cd due tr n

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W d, !c t ve

e. culd toldu joirt. In the spe s.'itot

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' n leving intte.11ction and trlibrntion of a spare speed svitch, cnd j

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'as te.lle.t ien of addi tional field ins t rumenta len to monitor

.f qu i pr.ent,rarformance, ECG l-2.ns succenf ully idle str.rted late I

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ca Deenbn; At 0100 hcurs, cr. December 5, E!* ' l-2 vas

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'st tco s s full;. f as t started and paralleled

.o the grid for

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spproxint.tely 1% heurs, then unloaded and ahutdown.

The test

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equip".pt vas removed, then EDC 1-2 var ognir idle started i

tuc ces s f u' 1..

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Sased en s revity of dnte frer the instrumented starts, review of

~f f ailum mechanism data p:ovided by the vendor, and successful teating f ollo.ing repeirs, EN 14 var declartd operabic and the TS

!.C0 vat ext:nd e.t 1421 hours0.0164 days <br />0.395 hours <br />0.00235 weeks <br />5.406905e-4 months <br /> on December 5, At 2340 hows on Dc:' ember 5, the ".ontrol rocia began receiving g

alna Lindi:ating trouble with EDG 12, incl.iding a diesel gl generator 1rekciu c.

The Syster F.ngineer r.rrived at 0100 hos s on L

Decerbor 0 and nbserved variour anoa.ulics involving the epcod f

svitch. A reviev of dcta c.ollected for the tiee period up to 0130

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hours on De:eabor 6 revealed voltage spiking on the DC power

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1.j The decister. vn :rnde to declaro EDG 14 inoperable end re-enter i) -

the T51.00 vith the s.are titulock as before, i.e., 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> ACT h.

beginning a: 03") hcurs on D20eP.bar. 3 cnd-expi:ing at 0500 hours0.00579 days <br />0.139 hours <br />8.267196e-4 weeks <br />1.9025e-4 months <br /> on

t Decceter 6.

N' 3

I th EDG M a.ill inoperable, in accordance vith TS 3.6.1.1, a

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. plant shutd:vn to Hodo 3 Tes emr.zenced at 0804 hours0.00931 days <br />0.223 hours <br />0.00133 weeks <br />3.05922e-4 months <br /> on December 6, and Nde 3 was entered at 10M. hours on December 6,

J '.f' TS 3.6.1.1 requires a continued cooldovn to Mode 5 vithin 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br /> q

of-reaching Mode 3.

In order to avoid a thermal traasient on the

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plant, a ter.porary valver of compliance f rom T5 3.B. I.1 Action a.

is requesici to allov the plant to rernain in Mode 3 f or up to seven

. f; days while :roub bshooting continues on EDG 1-2.

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' ) 'The cbracteristic symptoms of the EDG 1-2 f*ilures have not been - ' j@ _ i, observed on EDO _1 il. EDG l-I hea started and loaded vithout f ailure over the pas *. year. Tha failure is not 4-W lieved to be ir.minent un Y.0G 1,"!cce, a similar x f 1. Compensal g *i g x.h should this ts. se fer a temporn y u!ver fro: : 2mp'. ; ance be 'E grantsd, the follovh:g tocpenantory u ions veu)J be taken-durbr p: pm:f ormance ci the above descr; bed Mvi 1-2 natntenance act ivitin : ,;f i i '4-a) Other than feruired Technical Spr-!! ire.tlot' su:veillence kg test reautremente, edditional ces:ing or orovert iva l I g incintenance settvitf eu vill not be perfom >d on the EDG J4 1-1 or on T.cin 1 equipmen:. . : f.1. 7-b) Electrical Cistributicn equipment, eithr ncr::al, str.ndby

. k or tenerve, vill not be taken out of serviee.

In - Li[ addition hourly !.nspections of the-3451v switchyard.;1.1 s M' be perforited. Od _IN c) The Anr.d dispatcher vill be notified delly not to take F out of service any incoming tranamission lines to the ,f.._} f-DENPS, vxcept for emergency requirements. I its d) To preclude unnecessar-/ challenges being made to safety 4[j systeus, other safa :y ralated equipment vill not be taken ' l {i-out of'sevice. I'd iji e) The tiational Venther Service forecasts vill be monitored V L.I - by the DBNFS cieteorologist and the shif t supervisor updated periodically of-the vonther condition. The 9 current' forecast over the next week does not ' include any T severe weather conditions. Tempe a ures are expected to ' o (t : be slightly above normal with lovs in the range of 30-40 R degrees Fahrenheit.- If ice storms or other severe veather conditions *re observed, plant management vill , ); take appropriate actions. l n/ -. . _ Planned vork activities vill be prestaged to tae extent-L 1 _f). F F practical.and performed under an approved action plan. .r ' (hi g) CC1471,-CCV supply to EDG i-1 Jncket Vater 3 at '1p Exchanger, vill be left in the open position until 3 'EDG 1-2.is declared opere.ble. Thia valve autoctatically l opens when the EDG speed reaches 40 RPM to provide h. cooling vater flov to the EDG_ jacket veter heat

g exr.hange r.

I< >1- ![f$ $ I 7 ,..L t A__,

,..s Uconb W '4 uw ! c l V u:..W, .0 V W3 e '>. bb() h) EN 1.l vill be re-tentod in w:e duc<. d tn M {e 7 4.G.1.1.2.n.4, within ?4 hours of entry into Mode T. and at least every 72 houra thoronfter entil ED3 1-2 is [3, restored to opsrable s.tatus or the plant is placed in { J cold shutdown. Should EDG 1-1 become inoperable, the plant vill be pieced in cold 9hutdown within the d folloving 30 hours, j

1) Operating per sonnel vill be notified by Standing 0.1er to j

ensure these e.ctions are reintsinnd. ,u 4 h eliminarv ih alw ien M P fett 5 '. c rd M : anc e ni Po t en t h.1 f)- Consequences of the ProponeT6thsty a WW I; y The DMPS electrical system io designed in c nighly relisble ring h bus configutation. Tigure 1 it a n '.u n e. t ' disgre of n.e of f site i s, pover supplies, the non-mfety,;c1,.ted 13a kv busses (A and B) the J non-safety-relsted 4160V busser (c2 and D2), and the essential 4160V busses (rl end D1). It also shows the various bus interconnection pths. l' lh The initial 3 0 hv cvitchy rd design is a ring bus schene with k ultinate tre.nsition to a breaker-ud-a-half schwo. The 345 kv !( station svitchysed includes one line to Eay Shore Substation, one i line to Lemoyne subs tation, and ont-line to the Ohio Edison system. Three overhead 345 kv lina are provided from the svitchyard to the onsite station distribution syster.:, onu line to each of the tvo h. startup transformers and a third line to the main transforner. N One or both of the tvo 345 kv overhead lines to the startup transformers vill be available to supply all essential loads. The third overhead line to the main and riuxiliary transforners can be made available to supply all essential loads following a loss of all onsite alternating current pover supplies by reooving the generator main disconnect links. Y The safety function of the Emergency Diesel Generators (EDGs) is to a provide highly reliable, independent sources of power to the various components necessary for tne Engineered Safety Features (ESP) systems to function as assumed in the Safety Analysis Report ( S/tR). The ED0n are only required to function if the station's a main generator trips and the offsite pove'r supply to an essential bus fails. Bus load shedding and isolation, bus transfer to the EDG, and pickup of critical loads is automatic. During the period that the EDG l-2 is unavailable, all the other normal power supplies vill be available. The EDG 1-1 has been tested to verify it is functioning properly and is operable. Consee-,tly, vithout the EDG l.2 available to energize an . essential bus, there is sufficient flexibility and control vithin the electrical distribution system for plant operators to align one of the other power sources to the affected bus. I i k i \\ u 1

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.hI - The evitch N r associated.ith the system has been designed to 3 .~H ensure that no part of the system can be overloaded vithout "h actuation of automatic protective devices to ensure the continuity ff, of the pover supply. This unsures that faults are removed with ] minimal effect on the rest of the electrical system. f {} The safety function of the ESF systens is to protect the fuel y cladding, ensure the Containment Vessel integrity, and reduce the driving f or n fer matt irzcnt leakage in the event of a serMus iocL-cf-ccM snt n eidc t. The cyste c ,re de signed.::h lui. j;' redundancy so the no single failure.11 pt e.ent com ple t i er: of the ? h; safety fak tions, Ira addition, the system.; are periodically tested fp"- to ensure the.t the systens are capable of functioning as en used in the 531 au a? }). ESF components are dependent upon relisble elect rical power f.? supplies. _ lioveve r, it has been rccognized that the various aver Q supplies may, at timos, become unavailabic. The DBtPS Opera ting 8;;!i License, Appendix A, Technical Specification 3.8.1 1 provides a Liniting Condition for Operation in the event en EN cannot g con;)lete its rafety function, spec'fice.lly, pode 1 operatic: : ay Q continue for up to 72 hours, as long es the other 3.6..1 Action sp- -(e) requirements'are met. The Basis for Technical Specification N 3.6.1.1. states that the Action requirement provina restriction p! AJ upon continued facility operation commensurate vith the level of f degradation. It is considered that the probability of needing the p ESF functions durin:: a 72 hour period is sufficiently small so that the consequences of an event need not be of concern. h' The impact of extending the-allovsbie cooldovn tiec tc allev an y3 additional seven dras af ter entering Mode 3 has been evaluated by b comparing the core oelt frequencies associated vith less-of-cffsite f) {j power initiating event sequence. A loss-of-offsite power transient initiating event sequence vas chosen because it vould place the y greatest demand on the EDGs. w s ? A simplified-plant model vas constr ad and quantifie; for this sequence. This sequence evaluated tne resultant core elt frequency for the loss-of-of fsite power follovt:d by the loss of main feedvater, auxiliary feedvater (including the motor-driven -feedvater pump), and feed and bleed cooling. Two cases vore evaluated. For the_first, core melt frequency over a period of 31 dtys vas calculated assuming a 72 ' hour EN allov+d outage tina followed by a cooldown in the tineframe specified by ins Action statement. The second case also calculated a core melt frequency f over a period of 31 days, but vith an additional seven days in Mode 4 3. I1-A

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\\ hti Nu B n 1-Wi P- .7 t : Feults for Core na t f rego-ncy vith a sinpli fied rn ovety 'l approach for rescining offsite power vere as follovst i i - t, 4.76 x 10 9.15 x 10'6 per 31-dny interval Case 1 per 31-dny interval j Case 2 Il As shown by this evaluation, extending the allevable cooldovn time i by an additional seven days vill not have any significant adverse inpact on coro melt frequency. 1 )1 The ennacqucnces of an accident, given the electrical di:tribution conii;;u r t t i ca, vill no-ba signifitontly dif tet ent foi a seven day period in F. ode 3. Tnemfmc thsre is no significant increm 1: L the consequence, ef eny ;sreviously analy:cd accident. 5. Justificetion of Tenonrnry Vaiver of Compliance Duration

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Due to the need to perfora cdditional troubleshooting and the need to perform appropriate tests to demonstrate operability of the EDG 1-2, Toledo Edison (TE) is requesting up to an additional seven days after entering Mede 3, prior to tuntinuing the cooldovn. This extension has been shova in the above Section 4 not to have an i cdverse impact on refety. Accordingly, TE believer that extension of the allovable cooldovn time is justified due to the nature of the problem, and the extent cf the troubleshooting and testing activitics to be conpleted prior to declaring EDG l-2 cperable. 6. Basis for conclusion of No Significant Hazards Consideration The URC has provided standards in 10 CFR 50.92(c) for determining whether a significant hazard exists. A proposed 'emporary valver of conpliance involves no significent haze.rds consideration if operrtion of the facility in accordance with the proposed changes vouldi (1) Not involve a significant increase in the probability or consequences of an accident previourly evaluated; (2) Not create the possibility of a new or different kind of accident from any accident previously. evaluated; or (3) Not involve a significant reduction in a nstgin of safety. TE had reviewed the proposed valver and determined that a significant hazards consideration does not exist because operation of the Davis-Besse Nuclear rover Station Unit 1 ir accordu.ce with these changts vould: la. Not involve a significant increase in the probability of an cecident previously evaluated based on the above discussion.

a * : u n e r YJ - s !icem: Nx:bc r i.. -3 ' S N i r '<, Nurbe r 1-?f.7 Ace Ib. Not involve a significant increase in the cons 2quences of an occident previously eyelunted based en the above discussion. 2a. Not create the possibility of a nev kind of accident from an accident previously evaluated since there vill no change in ?.he plant's configuration except that the allovable cooldovn time is being extended. 2b. Not crene the possibility of e different kind of c.:cident from any accident previoual;, evaluated since there vill be no difference in the plant configuration a cept the allosable cooldovn time is being extended.

3. Not involve a significant reduction in a margin of safety as defined in the basis for any Tuchnical Specification.

As discussed above, there is no aignificant increase in the probability of experiencing a design basis accident and the same margins to safety which exist during the present TS l Action str.tement allovable cooldovn time vill still exist vith the extended allovable cooWvn time. 7. Essis for Conclusion of No Irreversible Environmental Consequences Inis request does not invclve a change in the installation or use f of the facilities or components located within the restricted arens as defined in 10 CFR 20. TE has determined that this temporary i vaiver of conpliance involves no significant increase in the amounts, and no significant change in the types, of any ef flut :s that may be released of fsite and that there is no significant increase in individual or cumulative radiation expoaure. Accordingly, the temporary vaiver of compliance meets the eligibility criteria for categorical exclusion set forth in 10 CyR Section 51.22(c)(9). Pursuant to 10 CFR 51.22(b) no environmental impact statement or environmental assessment need be prepsred in i connection vith the granting of the temporary vaiver of compliance. 8, C nclusion Ine DSNPS is currently in a TS Action Statenent on EDG l-2 due to activities associated vith troubleshooting the cause of tne failure to start following routine maintenance. A temporary valver of compliance is requested to extend the allovable cooldovn time by up to seven days. This extension vill be used to complete the troubleshooting and testing activities required.n EDG 1-2 and restore l' to operable status. It is proposed that this valver be approve immediately with the following conditions

Decket4 Nurubar 50.346 L4e.tase Nuraber NPP-3 Seria1-thtraber 1-967 Page 9

1) Tha valver vill become retroactively etfective at 1054 hours on December 6,1991 (t.irce of Hede-3 entry).

2) The valver vill expire ut 1054 hours on December 13, j

1991, or upon declaring EDG 1-2 operable, whichever is-earlier.- 3) If EDG 1-2 is.not restored to operabic status by 1054 hours on December 13, l'391, the coaldo., to Hode 5 vill cocmanca end Mode 3 vill be <,n a:ed by 1654 hours on Daconber 14, 1991. This request for temporary valver of co. plia:.ce has been reviewed and m approved by the DUNPS station Reviev Beard. Ifyouhaveanyquestions,p5ensecontactMr.E.V. Schrauder, Manager - Nuclear Licensing, at (419) 249-2360 Sincerely, 1 / i t [ -t ~ L'\\.A. ( le HKL/ dim cci J.-B. Hopkins, NRC Senior Project Manager - V. -Levis, DB-1 NRC Senior Resident Inspector J. R. Villiams, Chief of Staf f, Ohio Err.ergency Management Agency, State of Ohio (NRC Liaison) Utility Radiological Safety Board i

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