ML18139A038
| ML18139A038 | |
| Person / Time | |
|---|---|
| Site: | Surry, North Anna  |
| Issue date: | 03/07/1980 |
| From: | Stallings C VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| IEB-79-27, NUDOCS 8003110560 | |
| Download: ML18139A038 (4) | |
Text
'
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VIROINIA. EL_ECTRIC A.ND POWER COMPANY RICHMOND, VIROINI.A. 23261
- ~larclt 7,. l~~O.
Nr. James P.
- c.'Reili'y,: Director. - _.
Office of Inspectfon and -Enfqrcement -*
ti. s*~ Nuclear Regulatory.. Comni.:issiciil -
S~r{~l No. 185.
PQ/RGS: snw. -
Docket Nos; -, -50~280 so...:231 50-338 50::-339 Region II 101 liar1etta Stieet; *Suit*e 3100 Atlcnt2; Georgia: 30303.*- *
- License N~s:, DPR-32 DPR-37
- NFF-4 CPPR..:.78 :: -
Dear:
Jfr. ':o'.Re,Hly: _-
..:.-\\... '
____, _ *-rE: *iui1:t!t;r-,19~27 lfORTE.ANNA _POWER STATIO!T UNITS l AND_ 2 -_ : -
-<. SURRY:. POUER STATiot:(UNITS 1 'AND 2
\\
_1
_ This :is\\iri,. respd1~;e -to,.:i:E nui le t:"::tn i9-::-i7; )~-Lo~i 'of.,1-fo~-..:.r.i-~ss IE Ins trumen:t~ tioµ
...,-_ an~-fc?~trol jiower sy*s-tilliE~s Di:iring*cfperati_on".., --. * -: * *. _--,
Ve_ have interini
- date*.-_
not. C:omp~,e~~d'._ou~ irevie~~ :of: the subjecJ:_- bulleti~; ;: but'.the foli'oki.ng
- i:'Csp:onse._ to IE* Bull_etin 79-.:.27 provides, the -'status - of*- our revief1 to
- . *, ' ' -~
rmc
- Reauest.. _
_ ' :r.1c1)*: I{eviet1-'.'the class* IE' and non-.class IE b~ses ~~pplying power. to.
'safety *and "non.:..*safety-related -fostrument~:tion: and cqntrol sys-'._
tems wh:i.cll '~ould affec.t 'the' ability. to' achie~;e :a: cold: sl~titdo~.;n - '
ci::mditfon - u:~irig. exist:Lrig procedjJres:. pr' procedm.~es - developed
-Under--ite1rr,2 beloY~. F~r each btis:' ' _-
_* a) :rd~ntify and re;i~w* the alarm and/or indication. prcivi'rJed in the _control *room-_ to -aiert.*_the. operator to the loss of po..rer 'to the bus. - '.
b) c)
-- I~~~tify th~ inst~u~erit and control- ~ys-tem io~<l~ connected*
- to the -bus and *_ evaluate th-effects o,f ioss
- of - pol.ler, *to
_these loads including the ability* to a~hievc a cold shut-
-<l,;nm *c_oriditibn.
riescr'ibe -any proposed* design modification;: re*s_iilt'ing from *
.these reviel,S and evaluationG, and your proposed_ sche~ule rr' for :ir.lplementing those modifications.
11 o..P~ \\.
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~l O O 3 i:1* O ~(?
(j)
- ,. ~
Nr. James 1). O'Reilly, Director Respon*se.*.*
NRG Request*
l ~a* The results of our review indicates that,the operator has
. available in the control room alarm and/or,direct indica-tion for the loss of power to the vital and D.C. distribu-
- tion sy'sterils for the.Horth Anna and Surry stations.
Tbe~e
.ar,e no alam..s *and/or direct indications for the loss of.
. semi-vital buses in the* control room.
Eowever, the opera-
- . tor crin b~ alerted by a combination of alarms and/ or indication from individual instruments or equipment and
'determ:i,ne that a loss of power has occurred.
1 ~ b All it1stru~ent* and control system l_oads connected to* the vital,.. semi-vital and D.C. buses have been identified for.
- *1iorth Anna Units i & 2. ~nd Surry Unit 1.
The rev*iew of each bus for
- Surry Unit 2 i,rill be completed in the near
'future. It. is a:nticipatcd that the evaluation of the;
.cf,focts *or loss of. power to these. loads, includ:I.ng the
- ability to. achieve hot' and cold shutdm-m' conditions wil-1' be canplet~d by Jun~:1, 1980~.
1.c If any*,.design.i:r.odificat16ns resulting from our revtmj and evaluation.. are required, we will provide a' schedule' for the iraplenie'ntatfon 'of,thc.)se' mcidificationE;J.
11(2).
- Prepare emergency* procedures Qr review existinB ones that will*.
be used* by :control room operators, includ:lng*procedures re'quired
- . to achiev~ i1 cold shutdown condition, upon loss* of power to each
- class *rW and non-class IE* pus supply in~ pom~r.* to safety and 11011-safety...-rclatcd instrument and'.c6t1trol systems~
The e'n1er8ency procedureG should include:
a)
The di~gnostics/alarms/indicators/symptoms resulting 'from the* review and evaluation. conqucted per item 1 ab.ove.
b)
The use of alternate i~dicaticm and/.or control.circuits which. may be powered from other ~on-cla~s IE or. class IE
'instru~entation and control bµses.
c)
I-iethods for restoring power to the bus.
Describe any proposed.design modification of administrative con-trols to be implemented... resul ti.rig from..these procedures, and your proposed schedule for implementi.ng the changes."
f~esponsc
- 1.
In an ation it ii, effort to proyide the comprehensive rev.iew nnd evalu-
- 1' of t.he *energency pr,oced_ures. that.):la:s been r.equE1s_tcd.
our intent 'to '*:complete.the review and.evaluation of
.1
I*
I*
I m:.c Request e
e Mr. James P. O'Reilly, Director i tern 1 prior to addressing all the concerns set. forth in i tern 2.
We are continuing our review of existing proce-
- dures, but based on the above approach* we intend to respond with the results of our review and actions to be taken on or before June* 1, 1980.
n(3)
Re-review IE Circular No. 79-02, Failure of. 120 volt Vital AC Power. Supplies, dated January 11, 1979, to include both class IE and non:-cla*ss IE. safety-related power supply inverters.
Based OD a,revie~ of operating experience and your re-review of IE Circular r{o. 79-02, describe any proposed* design rnodifica-
- tions' or adr~inistrat ive controls. to be. implc~ented as a result of the re-review."
Response
- 3.
\\:e hav*e rercviewed II: Circular 79-02 to include non-class IE power supply inverters.
The fol louing describes the results of our review for both cla~s IE.and non-class IE inverters.
a)
For North Anna Units land 2 class IE inverters, there is no p.1:ie delay. circuitry or direct al tern.ate 120VAC current' input.
The alternate DC power supply is* fro1;1 batteries.
rhere is an alternate 120VAC power source
,.,.hich.is ir.anu.11ly actuated through an external trans-fer. s;_1itch.
This is used only. as a tmintenancc by-pass device~
Based on this arrangement~ items 1, 2 and 3 to the referenced Circular are not
- uppl icable *.
tlith regard to item 4, maintenance. procedures i.nclude reset of the manual transfer switch after naintenance
- is *complete* and ensures operability* ot the safety system*.
For North Anna Units 1 and 2 non-class IE inverters, there are two inverters which supply. po~ier to each of the two units cor::iputers *. Unlike vital bus inverters, each* computer inverter has a static *transfer switch which switches automatically to an alternate AC.source upon losG of inverter output.
'I'his transfer* also may be done manually.
There is no time delay between loss, of inverter output and*automatic transfer, therefore, item 1 of the Circul.nr does not apply.
There is no AC input to the computer inverter. therefore. item 2 does not apply.
The station ope.rating history indi-cates the mnxirmm availability of the computer inverter to continuously supply the load and requ.ires no modi-fication of the transfer circuitry or setpoints per item 3.
Administrative controls, item* 4*,* exist to ensure operabilitY"
- of safety. i=;ystews. after subco1:1-ponents have been subjected to maintenance or testing.
b) c)
"1:'(!s'/s='lr* c1~*r,
'*'-:.* *,u ** :J.Q.
- e Mr. James p*;. *ff'Rei'lly", D*irector :-
The rer,ev;ieH oi 'iE' Cii,cµl?r 79-0.'.2', for Surr.y'*'.tJnits 1 and 2.has not been comp)e.:ted~
.. Ue expect 1;o have. this review complete by April 15,. 1980..
In general, the.?dminlstrative controls. employed at North.Anna and Surry ensures the operability of safe.ty systems aftci: i:raintenance by the performance
- of
- asso-
- ci~ted periodic tests* which directly check tl1e in-strumentation and control logic without the initiation o'f the safety. function.
Very truly yours,
. z;_7/J1. ~~Jic:zJ!,t~~1,:J>..
- C. Mi Stailinis Vice President.- Power. Supply
- and Production* Opera'tion(:3 * *
' ~:,..
cc:** Hr *. Victor* Stello, Dir.ector
. Office :o*f irwpection and 'Enforcement*