ML19261D685
| ML19261D685 | |
| Person / Time | |
|---|---|
| Site: | Crystal River  |
| Issue date: | 05/16/1979 |
| From: | Chilk S NRC OFFICE OF THE SECRETARY (SECY) |
| To: | |
| References | |
| FOIA-79-98 NUDOCS 7906260056 | |
| Download: ML19261D685 (8) | |
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~ : 90-01 tri1TED S~ATES 0? AMCA NUCTSM RFm'I.MC'tY CCroilSSICN h'
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F'cRIDA PCEER CCnPORATIW, LT AL )
Docket No. 50-302
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Crystal River Unit No. 3
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Nuclear Generating Plant
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ORD R I.
Florida Pos 2r Corpore. tion (FPC or 'te license?). nd 616*/in Oth3r CO-cMCrs are the holders "of Facility Cp3 rating License No. DR-72 'atich auth0riZcs t".c operation of the nuclear power rec: tor kno'an as Crystal River Unit No. 3 Nucle:r Generating Plant (the facility or Crystal River Unit 3), at steady state power levels not in excess of 2452 inegaatts therr.al (rated ;xw.cr).
The facility is a Babcock & Wilcox (B&W) designed pres:surized water reactor (PAR) located at the licensees' site in Citrus Cou.ty, Florida.
II.
In the course of its evaluation to date of the accident at the Taree Mile Islard Unit No. 2 facility, which utilizes a E4W desicned P.G, the Nuclear Regulatcry Con:nission staff has ascertained that B&W designed reactors appear to be unusaally sensitive to certain off-normal transient conditiens originating in the se ndary system. The featureu of the P4W desian that centribute to this sensitivity are:
(1) design of the steam generators to cperate with relatively c:all li lid voltres in the se:ondary side; (2) the lack of direct initiation of reactor trip up:n the 2312 266 y%
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._ occurrence of off-normal conditions in the feedster systc=; (3) relicnce on an integrated control system (ICS) to automatically regulate feedrater flow; (4) actuation before reactor trip of a pilot-operated relief valve on the prir.:ry system pressurizer (stich, if the valve sticks open, can aggravate the event); and (5) a low steam generster elevation (relative to the reactor vecsel) which provider a naaller driving head for ratural circu-latien.
Because of these features, E4W designed reacters place acre reliance on the reliability and performance characteristics of the auxiliary fem.ater syste=,
the integrated control systen, and the emergency core cooliry system (ECC3) performance to recover frce frequent anticipated transients, such as loss cf offsite pomr and loss cf no=al feedwater, than do other RG designs.
'This,
in turn, places a large burden on the plant operators in t'h3 event cf off-nor:nal ry,te- %havior durirg such anticipated tra,sients.
As a result of a prelic.inary review of the Three Mile Island Unit 14o, 2 accident chronology, the NRC staff initially identified several hwan errors that o: curred ducire the accident and contributed significantly to its severity. All holders of operating licenses were subsequently instructed to take a nm.ber of iWiate actiens to avoid rep:tition of these errors, in accordance with bulletins issued by the Conraission's of fice of Inspection and Enforce 22nt (IE).
In additic:
the IEC staff began an innadiate reevaluation of the desica features of El
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~~ reactors to determine whether additienal safety corrections or ir: prove.mants were necessary with respect to these reactors. 21s evaluation involved n'z rarous meatings with BrtW and certain of the affected licensees.
'"he evaltation identified design features as discussed alrve which indicated that MW designed reactors are unusually sensitive to certain off-nor.:1 trar.0ient eenditiens origirating in tha sacendcr/ syste.:.
.b c result, cn additienal 5211etin was issued by IE which instracted holders of operatir,g licenses for B&W designed reacters to take further actions, incitx31rq 1.nediate changes to decrease the reactor high pressure trip peint and increase the pressuricer pilot-operated relief valve setting. Also, as a result of this evaluatien, the EC staff identified certain other safety concerns that warranted cdditional short-term desicn and procedural changes at cperatirq facilities having sow designed reactors. Tnose were idantified as itc=c (a) through (e) en page 1-7 of the Office cf Nuclear Reactor Regulation Status Reprt to the Cocmission of April 25, 1979.
After a series of discussions bet een the 20 staff and the licenseo concerning possible design rodifications and changes in operatire procedures, the licensee
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agreed in a letter dated May 1,1979, to perfo:n promptly the following acticns:
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7590-01 (a) Upgrada the timeliness and reliability of delivery from the Emergency Feedvater System by carryirq cut actions as identified in Enclosure 1 of the licensee's letter of Ray 1,1979.
(b) Devel:p and imple:~ ant opr:ratirq procedures f : initiating c-d centrollirq e: argency feet. cater indep2ndent of Inte-grated Centrol Systec control.
(c) 2plemnt a hardwired control-grade reactor trip that would 6: acttnted en less of train feedwater and/or turbine trip.
(d)
Complete analyses for potential s:all breaks and develep and icplemnt operatire instructicas to define operator action.
(e) All licensed reactor operators and senior reactor operators vill have cc: pleted the tree Mile Island Unit No. 2 ('mI-2) sinulator training at B&W.
Ir) its letter the licensee also stated that the facility is shut dc%n and would re::.ain shut down until (a) through (e) above are co:npleted.
In addition to these modificaticns to be implemented promptly, the licensee has als: proposed to carry out certain additional long-term rr.:dificctions to furth:r critnce the caprtility and reliebility of the reaccor to re.sp:nd to ctrious trc.rir.: e-ints.
Tnts: are:
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75 M-01 - The licensee will make codifications to provide verification in the control room of eiergency foedwater flow to each stem.:n generator.
ne licensee will subnit a failure node and effects analysis of the Integrated Control S ste:n to the KRO staf f as socn as prac-i ticable. S e licensee s ated that this en:1ysis 10 rwi underway with high priority by B&W.
- Tne reactor trip following loss of main feedvater and/or trip of the turbine to be installed procctly pursuant to this Order will thereafter be upgraded so that the com;cnents are safety grade.
Se licensee will subrait this design to the NRC staff for review.
- The lice.see vill continue reacter operator training and drilling of response procedures to assure a high state of prep:r'edn:cs.
The Cornission has concluded that the pter.pt actions set forth as (a) through (e) above are necessary to provide added reliability to the reactor system to respond safely to feedwater transients and should be confirmad by a Conraission onder.
Tne Co:rnissien finds that operation of the facility sheuld not be rentned until the acticas described in paragraphs (a) though (e) above have been satisfactorily c =;1ctcd.
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7550-01 m-For the foregoirs reascas, the Cecrnission lus found that the phlic heald, safety and interect require that this Order be effective i=rediately.
III.
Cepies :f de followiry docarnt: are available for inspection at the J:missi:. 's Public dec.ent R o-at 1717 H Street, N.d., Wechirr;;:n,
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2:5d, c.nd are being plcc+d in the Cc:niscion's local phlic d:>:'mt roce in the Crystal River Phlic Library, Crystal River, Florida, 3232.3:
(1)
Cffice of Nuclear Reactor Regulation Status R2porc on Feeduter Transients in BAW Plants, April 25, 1979.
',Attor frca S. L. Griffin (FIC) to Harold Danten (NRR) dated Vay 1, (2'
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Ac ::dingly, pursuant to the Atomic Energy Act of 1954, as amahd, arx1 the Cea-ission's Rules a xi Regulations in 10 CFR Parts 2 ard 50, IT IS HF_RESY CR E D m AT:
(1) Tae J icensee shall tihe the folle.dag acticas with respect to Crystal
~ P.iv.tr Unit 3:
(a:
'Jp rcie de ti.-aliness cnd ralithility cf delivery fror, tho
- -:rgacy had..--' c r Syste.: L,.' carryin Ou: 2:tiens as idcatified
- .. 2.: lost:2 1 on the licr.cc.2 's letter of Kr/ 1,1579.
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Develop and 1. plenent cperatiry procedures for initiating ard controlling emergency feed-ster independent of Inte-grated Centrol Systen control.
(c)
Ieplement a hard-wired control-grade reactor trip that would be act>nted on loss of.ain feedwater and/cr turbine trip.
"d plete analyses for ptential s:rall breaks anf develop ard (d) i.~01ement operating instructions to define opsrator action.
(e)
All licensed reactor cprators and senicr reac or eparators will have completed the mI-2 simulator trainirrg at m'.
(2)
Tr.e licenses e.all tuintain Crystal River Unit 3 in a snutd%n c:nditicn (the facility was shut down en April 23, 1979) until ite.:s (e) throuch (e) in paragraph (1) abcve are satisfzetorily completed.
Satisfactory co=pletion will require confir:.stien by the Director, Office of tbclear Reactor Regulation, that the actions specified have been taken, the @ecified aralyses are acceptable, and the specified
,1=ple enting procedures are appropriate.
(3)
The licenrea chall as prompl:ly as practicable also. accomplish tha long-tem redifications set forth in Section II of this Order.
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7590-O'. V.
Wit'.1. rsanty (20) d.3y: of the date of this Order, tha licer. sees or ary parson whose interect :.:y be affected by thic Order may recuest a heari.m with res:>:ct to this order.
Any such request shs11 rot s* y a
the 1.~..Mia:e effectivenem cf thf s Order.
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Cated at Washin: ten, D.C.
this f /l. day of'P.2y 1979.
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