ML18018B159

LER 77-015-00 for Nine Mile Point Unit 1 Regarding Lowering of Reactor Water Level Below Authorized Elevation

ML18018B159
Person / Time
Site:	Nine Mile Point
Issue date:	04/13/1977
From:	Bartlett J Niagara Mohawk Power Corp
To:	O'Reilly J NRC Region 1
References
LER 77-015-00
Download: ML18018B159 (8)

Text

NRC FORM I 2. 78 I 1QG "0 U.S, NUCLEAR REGULATORY CC"'SSION NRC DISTRIBUTION FDR PART 50 DOCKET MATERIAL DOCKET NUMBER 50-220 FILE NUMBER INCIDENT REPORT TO: J.P .O'REILLY FROM:NIAGARA MOHAWK POWER CORP. DATE OF DOCUMENT SYRACUSE, N.Y. 4/13/77 J . BARTLETT DATE RECEIVED 4/20 77 OLETTER ONOTORI2ED PROP INPUT FORM NUMBER OF COPIES RECEIVED

@ORIGINAL Z3UNCLASSIFIED QCOPY 1 SIGNED DES C RIP T I 0 N ENCLOSURE LTR. TRANS THE FOLLOWING...... LICENSEE EVENT REPORT if 77-15, ON 4/4/77 I CONCERNING SHUTDOWN COOLING RiiMP TRIPPING....

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'PLANT NAME! NINE MILE PT. // 1.

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~0~0'mOVg NOTE! PERSONNEL EXPOSURE IS INVOLVED SEND DIRECTLY TO KREGER/Jo COLLINS FOR ACTION/INFORMATION BRANCH CHIEF!

W 3 CYS FOR ACTION LIC, ASST,:

W CYS ACRS CYS HOLDING S NT INTERNAL D ISTRI BUTION REG PILE NR~DR I &-E (2 MIPC SCHROEDER/IPPOLITO HOUSTON NOVAK/CHECK GRIMES CASE BUTLER HANAUER TEDESCO/MACCARY EISENHUT BAER SHAO VOLLMER/BUNCH KREGER/J COLLINS EXTERNAL DISTRIBUTION CONTROL NUMBER LPDR!

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NMP-0010 NIAGARA MOHAWK POWER CORPORATION iIIIIIk NIAGARA I 'r MOHAWK 300 ERIK BOUI KVARD WEST SYR*CuSK, N,V. ISZOR Ap~ 13, 1977 QEt'E ( v[0 MII.. James P. O'ReiLLy PMmtoh.

U~ed S~u NucLexn. ReguLato~ ConnLeaion APR30>sv INMcIl Region I U ~ S. IIIICLEAkRNUlXARC COMM 691 PaIck Avenue, King o$ P~aia, PA. 19406

SUBJECT:

Lowing o$ Reavow @atm LeveL BeLouI ALthomzed ELevation - Nine h4Le Point NucL~ S~on <1 Sock& No. 50-220 Licence, 8PR-63 Licensee Event oM 77-15 "SI'entLemen:

Re LER The. (oLLoccing event oe~ed at Che Nine NLe Point NueL~ S~n <1 at appcoximateLy 0455 on Ap~ 4, 1977. IC uIM eepoMed by CeLephone and eonPfuned by (amimiLe ~mmQaaon on Che same day.

NhLLe an op~os ups Lolerung tcea~c NateIc LeveL $ oa Che pIdcpoae o$

pen,$ o~g majoa maintenance in Che aea~e vuaeL, a ahutdouIn cooing pump

~pped oft eaubLng mpLd deeIceue in eateA LeveL )room aboLt 294'9" Xo 299'6".

TeehnieaL Speci,geatione p~ Lou1efung Che LeveL Co 299'9". Pump ALON and uIcctm LeveL uIeIce immediateLy aeeCoaed, however, reactor eatetc LeveL momenkuciLy JeLL apptoximateLy XMee inch'eLouI Chat pe)un~ed by TeehnieaL Spew.gcatiom. TRQ eve'u been aevieved by We Skye Op~ore Review Committee and aepoMed Co Che Safety Revive and Auckt Boa/cd.

CIRCUMSTANCES o$ a, Reactor uIateIc LeveL had been Lowered in She aea&oc Co ahieLd and uIorck pLat'Joan on Che Cop o$ We cease shroud @ange. A(Net p~ ~&Lotion pLaeement o$ We ahieLd pLatfoen, an operator um (uIcthm LouIeIIing aea~c Natm LeveL in accordance ~h approved pjcoeeduItm by deaiMng (corn a ahLtdoln eooLing Loop. At Xhe same ~Ie, a second operator un'oehto~g uIaten, LeveL above, We eoae. ALL prumatcy agt~ and moLatcon vaLvm which might affect veIIaeL Nates LeveL uIeIce eLoaed oft except We Shutdown Cooking System and Che manuaLLy eoetfcoLLed chain. LeveL uIae deeceuing very aLouILy.

A hose connection (jcom Che condensate ~ne(m system i+to Che jceamoe annulus gaea ups provided ae a means o$ tvatw adckkion boa adjM~g aeactoc uIatn LeveL. Mateo. can aQo be, suppLied ming &e Liquid Peon System and We Coee Sptcay System.

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Page. 2 CIRCUMSTANCES (coetinued) e Co~uous op~on o( Xhe, shutdown cooling agfem was 'eeq~e'd Xo I

main~n a desired Low rceaMoa wats Xeyp~~e. The eh&down cooling ayaZem, by connections Co Che cease tce~culation piping, Wkes du~on (corn Xhe >reactor annu6u >scca, and ~chuiges into She aeaMoi. inlet plennum.

0/atm passages

~culates u~ plat(own in Xhe aEield Chrcough She (ueL assemblies, on Cop o$ She s/aloud (Lou@ Xhrcough She andi +to Che annulus QJLea.

Probable cause, o$ She shutdown cooling pump prces6me due Co excessive Lowering o$ wats< Level

~pin was Low pump au~on Che aeaMox annulus gaea wMLe She op~e was Dain.ing wats )morn Che shutdown cooling ayaCem. Nhen We pump ~pped, Xhe wats above, 4he aeactoe coee &mined into She (mt'he atm zeached Che Level o$ Xhe ceaMoe aMoud, 3" above. She annulus'en.

(Lang e elevation.

As soon as Che operator monit'o~ng aeuMorc, water. Level noticed Che in-cepWon o$ Che mpid Mop in LeveL, Chuuning was 6Copped, She shutdown cooling pump was <et~ed, and wats addition 4&ough Xhe hose )corn the condensate

~$ m ag4em was in~ated. Since, Chese a~o>u immediately eesCoaed eeaMo<

wats Level Xo weLL above. Xhe minimum speci.P.ed, Chere was no need Co initiate Die a~dby wat~ ad~on pmvmions available Chtcough use o$ She Liquid Pomon System oa Che Coee Spumy System.

ANALYSIS Jusk pru'.oa Xo Xhe evert, watson, Level above. She aeactoa cue was l'6" above We 6/vcoud +ange. At She one o$ She pump l/lb" in

~p, Che coze was covmed by She 3'3 l o$ wats di()nence elevation between She Cop o$ She cone and Che Lip o$ She a&oud. Thee m Che Lowest elevation Xo wEich She wats above She cone could have, damned hect e Che coae" and ann~ arcea ace separated by She ahtcoud below CELe eLev~on, aLL. cenrcculation pumps mekeolated, and checlz valves Ae shutdown cooling agCem ptcevent back (Lowing (corn Xhe coae gaea Xo Che annulus mez. Hence,, )ox CEis op~on, Loca o$ shutdown cooling ayaCem gow wouLd not cause unwat~g o$ Che aeaMoa coze even She annulus afcea.

i( She LeveLLe dewan down CORRECTIVE ACTION To preclude $

co<re due Co dtuueing

~e mpid inmemenNL changes in wats LeveL over, Xhe aeuMoa wats Level down in Xhe annulus urea, an ad~onal monLto~g water. column has been aManged ao Chat opetcatom may exercise continuous amveiLLance o( eeaMoe annulus eaten. LeveL as weLL as wats Level above. Che coee. Prcocedmes have been amended Co include peovkeions foe use o$ She cease annulus wats Level monition,. Expel.ence subsequent to Whee event has shown Mat opercatom may easily maintain au(scient shutdown cooling gow foe She ceq~ed cooling whLLe holding wats Level in Che ann~ gaea above Xhe Cop o( She eeactoa aMoud. 0/eLL tcegulated adjusWe~ in ceaMoe wats LeveL luive also been success)uLLy completed using aeons (corn Che condensate Mans(m o< bleed (corn Che ah&down cooling.

Vefcy ~y you/a, J. B~ett Exec~ve Vice President MAS/mtm ATTACNfENT

I J

~LICENSEE EVENT'EPORT CONTROL 8LOCK: /PLEASE PR)IYIT ALL REQLIIREO ll9FOR?RATIDFII)

'6 LICENSEE LICENSE EVENT NAME LICENSE NUMBER TYPE TYPE

[on~] N Y N N P I Iio 4 1 1 1 1 ~01

~

7 89 14 V I I 25 26 30 31 32 15'EPORT aI REPORT CATEGORY TYPE SOURCE DOCKET NUMBER EVENT DATE RcPtRT )ATE

[oa~j coii'Y ~T ~L' 0 5 0 0 2 2 0 0 4 0 4 7 7 0 4 8 57 58 59 60 I 68 69 74 75 80 I

EVENT DESCRIPTION

~02 While o erator was lowerin reactor water level'o clear temporary shield work platform,'

8 9 '80 a shutdown cool in um tri ed causing rapid decrease in water level to approximately 7 89 80

~0 4 3" lower than ermitted b Technical S ecifications. Pump flow andiwater level were .

7 8 9 80 Minimum de th of water over the top of the reactor was 3'3 11/16" 7 8 9 80 toom LER'7-15.

7 8 9 PRME 80 SYSTEM CAUSE COMPONENT COMPONENT CODE CODE COMPONENT CODE SUPPLivR MANUFACIU>cR 1'8LATIDiN

~or ~CF 0 P' Z Z ~Z 7 89, 10,'1 12 N P 17 43 44 Z 9 9 47 CAUSE DESCRIPTION 0 8 CD Probable cause of um tri was excessive lowering of water in the reactor annulus area 80 IOOI 'hich su lies the um suction. Additional moni'torin of water level in the annulus 7 8 9 80 have been chan ed to reflect this moni'toring.

7 89 FACII.ITY METROO O" 80 STATUS N POWER OTHVR STATUS DISCOVERY DISCOVERY OESCRI TION Q7< G ~00 0 NA 44 8 9 1O l2 I3 45 46 80 FORM OF ACTIVITY COPITENT RVLEASEO OF RELEASE AMOUNT 0 ACTNITY LOCATION OF'ELEASE 7

HI8 9 Z Z 10 11 NA 44 . 45 PERSONNEL EXPOSURES NUMSER TYPE DESCRIPTION

)@~00 0 Z . NA 7 89 11 12 13 . 80 PERS'ONNIEL INJURIES 7 89 11 12 80

~j(glXK coNsEQUENGEs PROBABLE Q~g NA 7 8 9 80 LOSS OR DAMAGE TO FACILITY TYPE OESCRIPTIOiN Z NA 7 89 10 PUBLICITY NA 7 8 9 ADDiTIONAL FACTORS EH3 Additional anal sis and details are rovided in a su lemental letter report.

80 Qg

RECElVEO 00CU%t/T PBOCESSiNG UHlT 20 PM t 51 STl APR