ML20064H229

/03L-1 on 780626:during Increase of Reactor Pwr, Noted That Critical Pwr Ratio in 4 Symmetrically Located Fuel Bundles Was Below Tech Spec Values.Caused by Pwr Increasing Xenon Transient

ML20064H229
Person / Time
Site:	Vermont Yankee
Issue date:	08/10/1978
From:	Conway W VERMONT YANKEE NUCLEAR POWER CORP.
To:
Shared Package
ML20064H227	List: ML20064H226 ML20064H229
References
LER-78-017-03L, LER-78-17-3L, NUDOCS 7812180241
Download: ML20064H229 (2)

Text

~

n.iti "Updaceaefect-ereviousdepor: caCe //z:4/ic~

- LICENSEE EVENT REPORT CCNTACLBLCCK: l i

l l l l 1 lQ 6 (PLEASE PRINT QR TYPE ALL REcutRED INFORMATICN) l l  !

10 1:a 1

> e 17 IuCENsas T I V C:oE lY l s l i l@l0 10 l- 10 10 i4 ts 10 lo I- 10 10 10 a@l4111il111l@lsi uCaNsE NwMesa Is uCa.ssa rv s ao ar sa @

C

" 7 lT1 il ,c ,,"c 1@l015 1010 10 1217 11 @l0 16 12 16 17 18 @la0 l 8ma*CRT l 1101713 l@

i e so si coCxaT NvMsEa 64 sa sv ENT Cars 14 ears so EVENT CESCRIPTION AND PACSASLE CONSECUENCES 1o !2 6 l l 1oi2l I See aCtached sheet I

~

10 ! A l l l t o 6 51 I -

l lof6l 1 l lo ir! I I f

', , Q l I 7 s9 50 SYSTE M CAUSE CALSE COMP. VALVE COCE CCCE $b8COCE COMPCNENT CCCE SUSCOCE SUSCOCE loi3l l R I C l@ [I_j@ [z l@ l ? l UI E l L l Il Il@ l z l@ [z j @

7 8 9 to 11 12 13 18 19 23_

SECUENTf AL CCOUR RE N 01 RE*CRT REVtSICN t,g g .pc EV ENT VE A R REPCRTNO. COCE TYPE NC.

@ Ny,$ l 718l

_ 21 22 l_l 23 l 0l 11 7l 24 24 lA 27 l0l3l IS 3 lL l 2o g

31 l1l 22 ACTICN 8UTVAE EPSEOT $HUTOCWN ATTACHMENT NPACJ # RIME COMP, CO'**CN EN T

(

ACTICN CN #t. ANT METwCO WCURS SU$MeTTE0 8CRu wS. $UP'U E R MANu 8 ACTU R E R TAKENlx I@lz 23 24 l zl@

as l@ Iz l@ 28 l01010 01 27 40 LIJ@

el INi@ Izi@

42 43 Izi91919I@

44 47 CAUSE CESCRIPTICN ANO CCARECTIVE ACTICNS h IiioiI I Wl See attached sheet I

'.3 ] I I l ' i 31 I I lii4 11 I 1 a a so

! $A %PCWER OTHER $7ATLS CIS C RY CISCOVERY OESCmPT'CN l lt Isl W @ l0 I7 l8 l @ l NA l l A l@.l Operator Observation i A TivtTY C TEast i agt,gasE AucyNT op Activity LCCAffCN C8 RELEASE i

i i,

7 m tm @C as aELEAsgtz_f@l 8 9 10 ft NA 44 I L

• s NA 80 I

i j #Eascumgt Exposungs NuveER C EsCpieT1CN Tvrt

• NA l li 7 I' l 'o I o I o l@[1J@l

' 2

J

.Eas:NN " wu'p.Es '

Nuvata :EsCRirTrCN@

NA li i 4 4I 110 t 010 !@l12 i 11 I

50 u;35 08 Os CAMACE TO 8ACILITY Q

, f T'*E C E ~C Rs 0TtCN y NA l

i IL 1. l,ij@l 7 is i

,,,m E T'igc....,0N @ NaC UsE CNu .

l m H8 3LL61 7

i 10 NA I  !i'i'Ii 54 69 33 ;

NAuE CP PaEsaREn 'J . F. Convav ,,cy g; 302-257-7711  ;

l 781218029(

VTVY S1 05000271 LER 78-17/3L, Rev. 1 EVENT DESCRI? TION AND PROBA3LE CONSECUENCES Reactor power was being increased within PCICMR constraints following a scheduled power reduction. Nuclear ~ calculations at 1100 revealed that the critical power ratio was within the requirements of Technical Speci-fication Section 3.11.C. Updated calculaticas perforned at 1614 indicated that the critical power ratio (CPR) in four synmetrically located fuel bundles was 0.02 below the Technical Specification value of 1.31. Reactor power was then reduced by inserting control rods and calculations demon-strated that the actual CPR was restored to within the Technical Specif1-cation limit as a result of that action. There were no previously re-ported similar occurrences.

CAUSE DESCRIPTION AND CCRRECTIVE ACTION The cause of the occurrence is attributed to a power increasing xenon

- transient. There were no control rods *.rithdrawn or recirculation flev increases during the interval of the two critical power ratio calculations.

C t

C

.. .. . . _ .-