ML19224B858
| ML19224B858 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear, Cook, Crane  |
| Issue date: | 05/17/1979 |
| From: | Chilk S NRC OFFICE OF THE SECRETARY (SECY) |
| To: | |
| References | |
| FRN-790517-1, NUDOCS 7906270093 | |
| Download: ML19224B858 (7) | |
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UNITO STATES OF AVJ:RICA NUCLElv3 REGU*.XIORY CO'X,.5 SIC'i In the F4tter of
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ARKMAS P'htR & LIGHT COtPANY )
Docket No. 50-313 7s
.s AR.ANSAS h"r. LEAR CNE, UMIT 1
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L, The Adansas Power & Light Cer'.pany (the licensee er AML) is t I ncide of Facility Operatirq Licea.se No. DPR-51 which authorizes the operation of the nuclear p0wer reacter kncm as the Arkinsas Nuclear Ca.e, Unit 1 (the f Oility or ANO-1), at steady State power levels not in excess cf 2563 cegawatts ther:.al (rated oewer).
Ce facility is u Eabec:k &
Wilcox (B&W', Casigned pressurized water reactor (?n?) Iccated at t.e licensse 's site in Pope Cctmty, Arkansas.
II.
In the course of its evaluation to date of the a00ident at the ':hree F.ile Island Unit No. 2 facility, which utill:es a B&W designed MG, the Nuclear regulat ry C :mtission staff has ascertaine-d t..at EJ,W designed racetors app 2ar to te unusually ae.ritive te cercnn :!f-n:m.1 trarsi:m:
ce"ditions origiF.* ting in thO C-2 ^0 7.d I_ "f Eyst'.
'.7. 0 fi.:!u.ir af t',2 ru dt:!c;n th:t c:n:ribut to this atasitivit'; cre
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cte.:n emrsters ta en:r:tc. ith ral..t: valv 2..2:' ' cdi v:i=:n in :.5n a
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the lack of direct initiation of reactor trip up:n secor,dary sidei (2) the eccurrence of off-nen.al conditions in t'a fe:6.'.ter systt:n; (3) re-r liance on an integrated control system (ICS) te aut:.Tatically regulate feedwater flow; (4) acttatica before reactor trip of a pilot -optrated relitf Vflve en the pric'.ry syster prascurizer (kSiche if i 3 Valvc sticrf, open, can aggravate the event); anf (5) a lov ster. cenerator elevation (relative to the reactor vessel) stich provides a s aller driving head for natural circulation.
Se:ause of the m features, P4W designed reactors place more reliary:e on the reliability and perfor:ance c'*1aracteristics of the atrxiliary feed-water syste::, the integrated control system, and the c.s2rgerc/ core coel-ing rystem (fC.'S) porformance to recover frcr.; frequent a.n;icipctef transients, se:h as loss of offsite power and less of rorre1 feefa?.ter, tMn do other.% designs.
This, in turn, places a large burden en the plant op,trators in the c-rent of off-nornal systec behavior durirq suti anticipated transients.
As a result of a prelimirary review of the 'Ihree Mile Is,10.M Unit 16. 2 accident chrcnolcgy, the 160 staff initially identified sencral hunun errors tbit occurred during the c00ident and centrib ted sig..ifier.t.ly to its severitv. All h ! dor; cf opcritin? lic<r2.as v.nra d sag;'.r..ly in:trurtef to tr. ':2 a nuchar cf n:~.edir.te acticr.s to tr rid espriti:.
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7500-01 3-Offict of Inspe: tion and Enforcemnt (IE).
In addition, the NAC staff bege.n an i:r.,.ediate reevaluation of the design features of Br.41 ree.ctors to deternine Wether additional safety corrections or ir: prover.ent.s were necessary with re_w to these reactors.
'Ihis evalusit. ion involved numrous :tectings vid Eth' and aertsin of the affected license 2G.
'Ibe evaltation identified design
- tures as discussed above which indi-cated that E&N designed reactors are unusually sensitive to certain eff-ner:n1 transient conditions originatiryg ir. the secondary systen. As a result, an additicnal bulletin was issued by IE which instru::cd holdors of op2rcting if 0 cams for Bid designed ret.ctors to tah:2 furt.her a.ctiens, incitzdirrg if:r-4 dicto cht.nNs to decrease the reacter higi2 pressure trip print and increase the pressuri::er pilot-o:>2 rated relief valve settirr;.
Also, as a result of this evaluation, the IGC ctaff identified certain other safety concerns th;1t wurrented additioral short-term design a.d procedural changes at operating facilities h'.ving BaW designed reactors.
Wess were identified as items (a) throu:5 (e) on pt.se 1-7 of the office of exlear Reactor Pegulation Status Report to the cccmission of April 25, 1979.
IItcr a 5: ries cf dir:x.ciens betwaen the U.0 s ta'f t.r.3 the 11 cense 2 en t.=,ing ;; sible dairn,rsiificaricu arc c: r.; m-b c;;.ztig pra-
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i (a)
Upgrade of the ti:reliner.s and reliability of the E::2rce:cf Ecdwater (EW) systeo by performing tha ite.e:s specified in Enclosurs 1 of the licensee's May 11, 1979, letter. Changes in design vill be m%!:ted to 6e NT<C staff for reviw.O (b)
Develop afd 141(cent operatirr; procedures for initiating a.x! centrolling EN irdepchdent of Integrated Control System (ICS) centrol.
i (c)
In:plement a Intd-vired control grade reacter trip ' hat wculd be acteated en loss of main feedwater and/or on errbiro trip.
(d) Ceeplete anilyses for potential =.all breaks and develop a-j 1::plet,ent cporatirg instructions to define operator action..
(c)
At least one Lice ced Oparator who his Md '".ircc Mile Isla._d E.it !:o. 2 (T;tI-2) trainirg en the BM1 sinulater vill bc asignM to the centrol roon (one each shift).
i Ir. its letter the licensee also stated that MD-l was currently chut dca and would re.r.ain shut down until (a) through (e) abovv are cc:gleted.
In addition to these modifications to be i=plemnted prucptly, the licensee h:s also proposed to car f out certain additicral lo.q-ter:n endifications to further et.ance the cc;abiliry and relidility of the rc 0 tor tn regmd te variocz transient events. Ther-e are:
1)
The items in Snel03ure 2 of the liceraee's letter of Mcy 11, 1979, will b2 ir;olenented during the nec ou: age (fnllowirs cc.::pleti0n of the design cbarrge e gineerirq) t cald shutdown conditions dich is of ::.:fficient length t.o accoredate the change, but no later than the next refueling outage.
Further, the lictmee
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will provide a schedule for imple:ent'ng any other modificaticns idmtified as necessary as a result of the licensee's reviews s.%c en Enclceuze 1 of the licensee's letter.
The cesign charrges will be suh itted to the tGC staff for review.
2)
Tha failure mode.: a:d effects E.nalysis (WSA) of the ICS is t.:nderway with high priority by En'.1 and will be s:M tted as soe,
as p--~ M le.
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The licersse will centinue operator traird.rq and drilling of resperse procedures as a pan of ar, ow;oirq pr: gram to e.ssure the high state of readiness and safe operatien at P.W1.
"he Coccission has concluded that the prompt z.cticrs set forth as (a) tnrc'xn (e) above are necessary to provide added reliability to the rea: cr systcc to respond safely to feednter transients and thould be car.firred t y a Ccanissica order.
Che C0=issien finds 9.at Op: ration of CC-1 should not be resmM until the actions described in paragrapts (a) through (e) abova have been satisfactorily cec.pleted.
F0r the foregoirq rescens, the Cor.ission has founf that the Sub11 health, safety and interest req.: ire that this Order be ef'ec+._-ive irr e-diately.
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Copies of th'3 followirrg documents ara railable for ir w :icn at the Cecr-ission's Public %c.: ment Mem at l'117 M Strsot, N. W., Wamin-ton,
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2')S55, and are being placed in the C0:r.ission's loc:d pcbli-doc =unt rocza at Arksrsas Polyter.imic College,. Tcasellville, Arkansas:
(1)
Office of Nuclear Reactor Regulatien Statu.3 Papert on Feedwater Transients in EsW Flants, Arril 25, 1979.
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Letter frcx:2 William Cavarnugh III (AP&L) to b rold Danten (wJt) dated.%ay 11, 1979.
IV.
Accerdirgly, purs:. ant to the Atomic Energy Act of 1954, as tranded, and the ce sico's Rules and R.~.gulatiens in 10 CFR P:rts 2 and 50, s
H IS ar.cISY ORCGID ' ?.AT:
(1)
':n2 licensee snall take the follow'~ q articr.s ' ~i.h res;>S:t t0 /C:0-1:
(a)
Upgrade of the timeliness and reliability of the Fri systtra by perfor:nirs the ite.s specified in En lesure 1 of the licensee's letter of May 11, 1979.
Provide ci,arges in design for NRC review.
(b)
D2velop and i.:rplement operacirq procedt.res for initiating and controlling Ph' indeperdent of Integrated Centrol Systez. control.
(c)
- . :plement a hard--wired control-grade reactor trip that ww.id be actuated cn loss of : Min feedrzter and/or en turbibt trip.
(d)
Cer:alote a.nlyses for potential s=all brens and develop and implem+nt cperating ir.;tnr:Oicr.s to defire cporator action.
(e)
Assign at least one Licensed Opentor who has had 'IMI-2 training en the E4W si=tilator to 'de Ocntrol m (one each shift).
(2)
'Iha licensee shall caint. tin ANO-1 in a shutdce. coM.itien t.ntil ite.G (a) through (e) in paragrach (1) ab2ve are satisfactorily co qleted. Satisfactory ~c0c.pletion Will recuire confir,ation by 'tc Direc~or, Offic0 Of Nuclear Fge-tor F.2c a ~"c.q,
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. (3) Tne liccase.: thall ac pecep_ly as practicable also amlich the 1:r,;-te:u =:difiestions se: fcrth in Sc : :n !! of $10 C; der.
V.
W!:hin Wr.nty (23) d:ys of the date of this ordar,.he 11cer.cee er ar.y p:rstr whose interest nr.y be affected by this Order r ry rege,:: c hearing dth reUFee; to th!C C'-
ar.
Any such regle st 0.v.ll ret any the irnediate effectiveness of this Order.
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'S-cretary yf the C:ctia3 ion Osted A,(:.:nnin;uca, D. C.
this / g' t-day of Fay 1979.
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