ML20009D559

LER 81-008/01T-0:on 810611,shaft Vibration on Reactor Coolant Pump 21 & Seal 1 Leakoff Flow Increased Beyond Normal Range.Pump Disassembled.On 810706,circumferential Crack Discovered.Cause Not Determined

ML20009D559
Person / Time
Site:	Prairie Island
Issue date:	07/17/1981
From:	Hunstad A NORTHERN STATES POWER CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML20009D556	List: ML20009D555 ML20009D559
References
LER-81-008-01T-01, LER-81-8-1T-1, NUDOCS 8107240172
Download: ML20009D559 (1)

Text

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LICENSEE EVENT REPORT CONTROL BLOCK: l i

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(PLEASE PRINT OR T *! ALL REQUIRED INFORMATIONI lo l1l lM j N l P lI lN l 2 l@l 0 l 0 l - l 0 l 0 l 0 l 0 l 0l -l 0 l 0 l@l 4 l 1 l 1 l1l1l@l57 l CAT Wl@

7 8 9 LICENSEE CODE 14 15 LICENSE NUM6hR 25 26 LICENSE TD PE JC CON'T 10111 3$n"CE l L j@l0 l 5 l0 l 0 l013 l 016 l@l0171016 l 811 l@l017 l117 l 8 l180l@

7 8 60 61 DOCKET NUMBER 68 to EVENT DATE 74 75 REPORT DATE

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EVENT DESCRIPTION AND PROB ABLE CONSEQUENCES h l o l 2 l l On June 11, 1981 shaft vibration on No. 21 RCP increased from its ununi rango nf 6-7 1

[o ;3 ;- l mils to a range of.20-25 mils within eight hours. No. 1 seal leakoff flow also beganj

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g o [ .i ; l increasing. The unit was shut down and cooled down. Early pump ins,ection efforts I lol_sI L ndicated i the pump should be completely disassembled. Pump internals were removed, -l

[ o 16 l l decontaminated and inspected. On July 6th, a ciret:mferential crack throu;;h ~ 3/4 l lo;7l l of the shaft diameter was discovered. I l

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7 9 10 li 12 13 18 19 20 SEQUENTI AL OCCURRENCE REPORT REVISION

_EVENTYE#3 .. REPC 9T NO. CODE TYPE NO

@ =LER/Ro  ; .l 8 l 11 l-l l 01018l l/l l0l1i 2d LT_1 30 l-l Lo_1

_ 28 22 2J 24 26 27 29 31 31 K A ON ONP NT METH HOUHS SB IT FOI t hub. SU PLIE MAN F ACTL,R E R lJJAlgl34Xl@ l35A l@ l36Al@ l 0l 9l 3l 6l 3/ 40 b@

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43 lW-l1 44 l 21 Ol@ 47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h 11 l o l l Cause unknown at this time. The shaft was shipped offsite for detailed examination. 1

[i j i l l A replacement rotating assembly was procured and reassembly is in procress. A i

i;7g l ?allowup report will be issued. l 11 13!'l l I

12 1411 go 7- 8'9 STA S '6 POWER oTHER$TATUS b S OV F D!SCOVEllV DESCniPTION

'l 1 15 I [gj@ l Ol 0l 0l@l NA l [_CJ@l Physical.0bservation l A IVITY CO TEW RELEASE AMOUNT OF ACTIVITY loc ATION OF RE LE ASE l 1 l 6 l [Zj @D OF RELEASE NA l Zl@l l l NA l

,eRSOwEtE,0sSts NuesER TYPE oESCRiPTiON @ ion to be supplied in the followup report l l 7 l l 0 l 0 l 0 l@l Z l@l Informat "

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L imuns N UP.4B E R CESCRIPTION li la i lo l o lo l@l NA l

toss OF on oOa4cE TO FACILITY - 8 07240172 810717 TYPE cEsCRiPT.o. PDR ADOCK 05000306 l t l 9 l [Zj@l NA S PDR l p-7 ts 9 10

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ISSUED DE SCniPT60N y [][j@l Plant Status Reports on 7/11/81 and 7/19/81 l l l l l l l ,1. l J l l _LJ .

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