ML20236F536
| ML20236F536 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 10/22/1987 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20236F523 | List: |
| References | |
| NUDOCS 8711020194 | |
| Download: ML20236F536 (4) | |
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NUCLEAR REGULATORY COMMISSION.
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I SAFETYEVALUATI'ONBY'THE0FFICEOFlSPECIdLPROJECTS' W
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SUPPORTING)AMENDMENTNO.61i:TO'FACILITYDOPERATINGLLICENSENO.DPR-77!
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<W AND AMENDMENT NO.L5'3H TO FACILITYt0PERATING LICENSE NO.?DPR279) c
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- SE0VOYAH' NUCLEAR PLANT UNITS 1 AND '2j W'
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DOCKET N05.:50-327 AND 50-328.
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1.0 INTRODUCTION
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Thissafetyeval'ationaddressesproposedlchangeTVASON-TS-87-29ntobequoyshf['r.
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u Technical Specifications, Units 111 and 2.SSection 3.8.3.2;OThe:changefinvolves:
' deleting. and ' adding ;specificf motor-o'perated Jvalves f(MOV)(TOL)!from(those. re periodic surveillance testing!of their thermal overload l protective.
Tennesseef Valley Authorityf(TVA)pplemented by?atsubmittali.~ da devices.
In~a: submittal dated May115,11987, su June.16,1987, proposed: deletion?ofEthree c
categories of MOV and the: addition of one categ'ory toltable' 3;8-2 LofJthel !
Sequoyah Technica1 Specifications; 1Section 3.8.3;2 of the' Technical:Speci-j
>4 fications require that TOL'! devices for the;valv_es1specified in?theltable' bei l
operable, that the operability of thejT0LtdevicelbeMemonstratediperiodically L,
and :that the assocSted valve be declared 11noperable:when the?TOL of the! motor?
operator is~ found !to se inoperable.. The individu'altcategoriesi of MOVtaffected t by the proposed Techiiical. Specification change'are?as;follows::
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(1)
L M0V's'whose TOL device isLto/be permanently bypassed:andithsreforeTto!bei deleted from the table (Attachment 1;to 6/16/87l submittal).. ' '
-(2) M0V's no longer required.to be activ'e '(to change state.in normalloperationf or during accidents) as a result of changes'in proceduresf orfsystem,~..
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configurations ~ arising out of compliance with Appendix;R 'and< therefore' to,
q be'deletedifrom, the table' (Attachment 2 to 6/16/87; submittal) "
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,.i (3) Valves not required to. change 4 tate to prevent or mitigate an accident;;
J consequently.not required toLb$ tested under ASMELCode Part'1116Section 111
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.andthereforedeletedfromthe. table,(Attachment 3toL6/16/87Jsubmittal)'3 0
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'Valvss with TOL.devi'ces. required!to be operable andl inadvertently omittedl '[.
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f rom the techni cal : s peci fi ca tions [( Attachment l 4 ito 6/16/87; submi ttal ). ~
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q 2.0 " EVALUATION x
12.1.'M0V's with Bypcssed Overload Devices ~
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DuringanongoingreviewofelectricaUcalcu1'ations.TVALdiscoveredthatltheJ original voltage drop calculations for Sequoyah's' electrical system-did not'
' take into; account the voltage drop at motoreoperators caused by the. TOLo..
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-device in series with the. individual motor.'.When:this?effectlwas:consideredh 4
'the recalculated motor terminal voltage was. unacceptably low during.certain-transient loading conditions following;an1 accident? To: correct the situation,-
O TVA proposes to bypa'ss. permanently the TOL devices :for the;affected valvesi
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TVA. notes:as' justification, NRC's Pegulatory Guide 1.106 which'in paraphrase 1 during testing.or b). devices should be'either a) continuously bypa states that (1) TOL to IEEE-279.or (2) TOL devices be set.with 'all uncertainties: resolved in the?
direction of ccmpleting the safety? action', 'i' e., set high',L an'd periodica11yi H
tested. TVA further. states that, given;the high set point on1the1TOL devices' t
being bypassed, i.e., locked rotor current, there"isilittle ~ benefit to rein-1, serting the TOL. devices during valveToperation fo'r testing 7or; maintenance.s j
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The TOL' device provides two functions:.
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I (1) It pr'otects the motor in a lock $d rotor condition.
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It may detect by tripping during test progressiveldeterioratio:f of ?
1 the valve.or operator.
TVA has reanalyzed the circuit breakers associated'with the: motors t'o" assure; they will: provide locked rotor. protection 'andlwhere necessary hastreplaced'..
breakers; thus TVA' addressed the first function'.',TVA:has7 institu o
utility industry with NRC input to detect deterioration.r [Further, at the next :
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refueling outage TVA will: implement a= periodic main.tenance' procedure that :
will' measure alltphase currents'of the MOV's during testing.-1This' procedure 1 provides a"second means.'to~ detect defects intmotor operatorior yalve. 'The, i'
combinationoftheseclattertwo; programs; addresses 7the~secondfunction.
A review by the NRC staff and its t.onsultant of these programs supportslTVA's'.
j conclusions that the M0V's are adequately protected again.st electrical: fault a
orLlocked rotor without the'TOL:deviceland that: bypassing of the TottdeviceL will not' degrade system,or plant; safety. Fu rthe r,1the MOVATS ' program' wil la provide an' equivalent:and ~withithe'additionLof. periodic phase. current measure-ment ;-ia. superior means of detectingLmechanical'or electrical Degradation 3off the motorf operatori or valve.; ;ThereforeW the MOVATF program' provides f aireason-J able justification'for; not removinghthe bypass feature during' periodicLtestingh
<The possibility lthat the TOL: devices woulidete:tlelectrical' damage during:
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. testing:or2 maintenance,Cduringitheidevelopnent~ period:of;thel phase current % _
. monitoring /resulting in faultKcurrents thatLwould.notttrip;theffeederzbreaker, M.7 p'g 4
m Lis[ considered too remote to:.requireiremovaliof!the; bypass?
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~2.2' M0V's Deleted to Comply with 10 CFR Part 50', Appendix ~R d
2 A total of 10 valves are-deenergized at the' switchboard to conform to: Appendix R;,
'j requirements. The only. time they will normally?be1energizedlis: momentarily l
an hourk a fire watch will. be stationed. :Therefore, TVA" proposes deleting the '.
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TOL. devices for these; valve operators from theioperabi_lity ~ test;requi.rement.; lThe
' mj NRC staff and its consultant concur.
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2.3' Valves not Required to! Operate to Mitigate Accident's t
L Section XI of the ASME Code,.Part III requires: operability testingiof. valves l-required to change position'to mitigate an accident. This. operability testin.g4' requirement includes testing'of the TOL'. cA review by.TVA has ide'ntified116 '
H valves previously included in'this' category that:are actually 'not required l l
to change position. Eight are safety injection: accumulator valvesLwhich are i
l required by procedure to be deenergized'at the switchboard!in'anfopen position:
during operation.; Eight more arelvalves in the Essential, Raw' Cooling Water and Component Cooling sptems which do not enange position 1during"thenaccident;.
and'are used to provide flexibility in operation:or maintenance. 'The staff and.
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its consultant agree that these valves,.not being: required:to: change position 1 in an accident, need not have-an operability test requirement)for. theirc. TOLD devices.;
2.4 ' dditional Valves V
d TVA has identified 20 additional valves whic.h,'since they'are: required toi
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. operate for. accident prevention or'mitigatioce need'to have their'TOL' devices 4'
added to the list in the Technical Specificati ws. lThis'is acceptable to NRC staff.
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3.0 ENVIRONMENTAL CONSIDERATION
Theamendmentsinvolvechangestorequirementswithrespecttoithe[ installation
-or use of.a facility component-located within'the restricted area a'sLdefined in 10 CFR Part 20 and changes to surveillance l requirements. The-staff has deter '
mined that the amendments involve:no significant increaselin the-amounts, and no significant change in2the types.cof any effluents that may.be: released-j
.offsite, and that there is.no significant increase:in individual:or cumulative occupational radiation exposure.gThe Commission has'previouslyl issued'a pro c ji
< posed finding that the' amendments' involve no significant hazards consideration
.and there has been no:public" comment on such finding. :Accordingly, the: amend '
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'ments meet the eligibility criteria for categorical exclusion set forthlint10; CFR 51.22(c)(9). ePursuant!to~10 CFR 51.22(b). no" environmental' impact;statei E
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ment not environmental. assessment need be' preparedtinfconnection'with!thc; issuance of'the. amendments.-
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- 4.0' CONCLUSION-l
- Based on reviews by the staff. and its consultants, the. staff'concurslin ' he1 t
deletions and additions to1 Table 3.8-2 of the-Technical Specifications, Thel NRC staff notes TVA's commitment toLimplement a M0 VATS program priorJto restart of unit 2 and implement phase current monitoring of:all MOV's:(both those covered by the EQ program-and those not covered) during the next :
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refueling outage of Unit 2 and. prior to' restart ofsunit 1.-
-.1 JWe have concluded, based on the' considerations discussed.above, that: L(1).there l
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is' reasonable assurance that the health and safety of"the:public will.not be i
endangered by operation in the proposed manner, and-(2) such" activities lwill.
1 be conducted in. compliance'with the Commission's regulations..and theLissuance H
of the amendments will not be inimical to the 'conson' defense and security nor to
'j the health and safety of the public.'
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l Principal Contributor: Edward-F. Goodwin, Thomas'SE Rotella j
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Dated: 0ctober 22,'1987 q
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