05000260/LER-1983-018-03, /03L-0:on 830413,core Max Fraction of Critical Power Determined That Min Critical Power Ratio Exceeded. Caused by Withdrawal of Deep Control Rods.Control Rods Inserted to Reduce Core Max Fraction of Critical Power

/03L-0:on 830413,core Max Fraction of Critical Power Determined That Min Critical Power Ratio Exceeded. Caused by Withdrawal of Deep Control Rods.Control Rods Inserted to Reduce Core Max Fraction of Critical Power

ML20023D373
Person / Time
Site:	Browns Ferry
Issue date:	05/11/1983
From:	Stiles H TENNESSEE VALLEY AUTHORITY
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20023D368	List: 05000260/LER-1983-018, Forwards LER 83-018/03L-0 05000260/LER-1983-018-03, /03L-0:on 830413,core Max Fraction of Critical Power Determined That Min Critical Power Ratio Exceeded. Caused by Withdrawal of Deep Control Rods.Control Rods Inserted to Reduce Core Max Fraction of Critical Power
References
LER-83-018-03L-03, LER-83-18-3L-3, NUDOCS 8305200426
Download: ML20023D373 (2)

LER-1983-018, /03L-0:on 830413,core Max Fraction of Critical Power Determined That Min Critical Power Ratio Exceeded. Caused by Withdrawal of Deep Control Rods.Control Rods Inserted to Reduce Core Max Fraction of Critical Power

Event date:
Report date:
2601983018R03 - NRC Website

text

-.

4, N7t FCKM 366 U,$. NUCLE AR RESUL ATORY COMMIERISN APPROVED BY OM B Vo'c',4so LICENSEE EVENT REPORT 3880 00H CONTROL BLOCK: l l

l l

l l

l@

(PLEASE PRINT OR TYPE ALL REQUIRED INFORMATIONI l oli l l A I L I B I R I Fl ?lhl O I O I l OlO I O I O l nl 10 I n Ihl a 11 11 l1 1 1..lhl I

I.. h L,u..E E. O.E L,o..E.UM.E.

L. E,.. E T, P E

...AT CON'T l o l1 l

":30 [Lj@l015 l 0 l O l Ol 216 l 0j@I Ol 41 1l 3 l 8 l 3 l@l0 l 5 l 11 11 81 3I@

DOCRET MUMSER 6.

EVENT D ATE REPORT D ATE EVENT DESCRIPTION AND PROBABLE CONSEQUENCES h o2 l At 1723. while unit 2 was at 72.9-nercent nower returnine to rated power I

l o 13 l l followine a load dron for rod nattern adiustment. the Minimum cririen1 l

l o l4 l 1 Power Ratio (MCPR)% (Technical Specification 3.5.K) was exceeded as detertained I o s l by a Core Maximum Fraction of Critical Power (CMFCP) of 1.006.

There was no l

lol6ll effect on the hon 1th or nnferv of the nuhlic.

Thorn vern no nignifienne l

l o l 7 I I consequences.

l T

IoIell l

'ua"

.c:n:E

.::.":.E

.un:E

..M..~E

,...E loisi Iz I zl @ 1,,x.J @ W @ Iz 1z 1717121 zl @ W G l_2.J O c"n;;""

"n "'

E,E,,,EA.

@ Edi?. I 81 31 L..l 10 l i I a l I/I I Of,1 L..t.J I-I W

^n':"

',u"":

@ ^:M;"T,n'

'".'":P:,;"'

M ::" :",i"'E.8

..U..

l.x. J@l.2.J GL..zJO L.2J @ l ni nl ni d L..yJ @

L.J. O I vi@

l v io lo l a,I CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h lilo ll In nn neromne en 'lann rhn frnetinn nf vntnd n nun -- a k -.f n i-h n rNFTim deep I

liIill control rods were withdrawn.

Durine the nnsuing procnndi ci nning rnmp; Ynnnn I

I changes and low core flow resulted in hi local nowers. Rod movement reduced I

i 2 l i l 3 l l CMFCP to 0.970 by 1730. This is considered an isolated event and no further l

l i I 4 [ l recurrence control is required.

l 1

=

STAT s

% PO w E N OTHEN ST ATUS DISCOV E R Y OISCO V E R Y DE SCRIPT.ON l t l s l l F l @ l Ol 713 l@l NA l b @l Encineer Observarinn I

l NELE SED RELE E AMOUNT OF A.TIVITY LOC ATION OF RELE ASE I i f s I L.zJ @ L,.z.J@l ni i

I I

ni NUMBER TYPE D E S C R IPT,0 N I il 711010 i O l@U, @l na I

NUMBER E S C R IPT IO N 1i18ll nlnin l@l l

m

'%':"*"".*E." ^ t".' *O;" * "@

I i19 l W@l l

ni issuKo"[ 's'[niPT.On h NRC USE ONLY 12 l o l L.tJ@l v4 I IIlllilillllI (205) 729-0845 NAME OF PREPARER Harold Stiles psoye.

8305200426 830511 PDR ADOCK 05000260 s

PDR

Tennessee alley Authority Form BF 17 Browns Ferry Nuclear Plant BF 15.2 2/12/82 LER SUPPLEMENTAL INFORMATION BFRO 260/

83018 Technical. Specification Involved 3.5.K Reported Under Technical Specification 6.7.2.b(2)

• Date Duc NRC 5/13/83 Event Narrative:

Unit 1 was operating at 80.4-percent power and unit 3 was operating at 99.7-percent power.

Both units were unaffected by this event. At 1723, while unit 2 was at 72.9-percent power returning to rated power following a load drop for rod pattern adjustment, the nuclear engineer observed during normal monitoring that the Minimum Critical Power Ratio of T.S. 3 5.K was exceeded as j

determined by a Core Maximum Fraction of Critical Power of 1 006. The health and safety of the publio were not affected since the safety limit was not exceeded.

r In an attempt to keep the fraction of rated power greater than the Core Maximum Fraction of Limiting Power Density, power was increased by withdrawing deep control rods. During the preconditioning ramp, Xenon changes and low core flow combined to cause the MCPR to be exceeded.

Immediately upon determining the violation, control rods were inserted to reduce the CHFCP to 0.970 by 1730.

This is considered an isolated event and no further recurrence control is warranted.

• Previous Similar Events:

None 9

Retention :

?criod - Lifetime; Responsibility - Document Control Supervisor

((

• Revision:

l l

l