05000339/LER-1981-040-03, /03L-0:on 810508,axial Flux Difference Deviated Greater than 5% from Target for 28 Penalty Minutes During Rampdown from Full Power for Scheduled Outage.Caused by Control Rods Being High in Core.Rods Inserted

/03L-0:on 810508,axial Flux Difference Deviated Greater than 5% from Target for 28 Penalty Minutes During Rampdown from Full Power for Scheduled Outage.Caused by Control Rods Being High in Core.Rods Inserted

ML20004D619
Person / Time
Site:	North Anna
Issue date:	06/04/1981
From:	Cartwright W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20004D610	List: 05000339/LER-1981-040, Forwards LER 81-040/03L-0 05000339/LER-1981-040-03, /03L-0:on 810508,axial Flux Difference Deviated Greater than 5% from Target for 28 Penalty Minutes During Rampdown from Full Power for Scheduled Outage.Caused by Control Rods Being High in Core.Rods Inserted
References
LER-81-040-03L-01, LER-81-40-3L-1, NUDOCS 8106090588
Download: ML20004D619 (2)

LER-1981-040, /03L-0:on 810508,axial Flux Difference Deviated Greater than 5% from Target for 28 Penalty Minutes During Rampdown from Full Power for Scheduled Outage.Caused by Control Rods Being High in Core.Rods Inserted

Event date:
Report date:
3391981040R03 - NRC Website

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U.S. NUCLEAR REGULATORY COMMISSION LICENSEE EVENT REPORT g

CONTROL BLOCK / / / / / / / (1)

(PLEASE PRINT OR TYPE ALL REQUIRED INFORMATION)

/0/1/

/V/A/N/A/S/2/ (2)

/0/0/-/0/0/0/0/0/-/0/0/ (3)

/4/1/1/1/1/ (4)

/ / / (5)

LICENSEE CODE LICENSE NUMBER LICENSE TYPE CAT

/0/1/

g/ (6)

/0/5/0/0/0/3/3/9/

(7)

/0/5/0/8/8/1/ (8) /0 /6 S /4 /8 /1/ (9)

DOCKET NUMBER EVENT DATE REPORT PATE EVENT DESCRIPTION AND PROBABLE CONSEQUENCES (10)

/0/2/

/

On May 8, 1981, during a rampdown-from-full power for a scheduled outage, boron /

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/

was injected into the core to maintain rod height. At 79% power and decreasing /

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/

the Axial Flux Difference deviated greater than 5% from the target for a total /

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/

of 28 penalty minutes. Because the indicated Axial Flux Pi.fference was within /

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/

the limits shown on Fig. 3.2-1 of T.S. 3.2.1, the public h,alth and safety were/

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/

not affected. This event is reportable pursuant to T.S. 6.i.1.9.b.

/

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/

/

SYSTEM

CAUSE

CAUSE COMP.

VALVE CODE CODE SUBCODE COMPONENT CODE SUBCODE SUBCODE

/0/9/

/R/C/ (11) M/ (12) M/ (13) /Z/Z/Z/Z/Z/Z/ (14) g/ (15) g/ (16)

SEQUENTIAL OCCURRENCE REPORT REVISION LER/R0 EVENT YEAR REPORT NO.

CODE TYPE NO.

(17) REPORT NUMBER

/8/1/

/-/ /0/4/0/

/\\/

/0/3/

g/

/-/

M/

ACTION FUTURE EFFECT SHUTDOWN ATTACHMENT NPRD-4 PRIME COMP.

COMPONENT TAKEN ACTION ON PLANT METHOD HOURS SUBMITTED FORM SUB. SUPPLIER MANUFACTURER

/_X/ (18) /11/ (19) g/ (20) /Z/ (21) /0/0/0/0/ (22) /Y/ (23) M/ (24) g/ (25) /Z/9/9/9/ (26)

CAUSE DESCRIPTION AND CORRECTIVE ACTIONS (27)

/1/0/

/

The power distribution deviated from the target delta flux band during power

/

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reduction due to the control rods being high in the core.

Delta flux was

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returned within the target band by inserting rods as the power reduction

/

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continued.

/

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/

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FACILITY METHOD OF DISCOVERY DESCRIPTION (32)

/ (30) DISCOVERY STATUS

% POWER OTHER STATUS

/A/ (31)

/

OPERATOR OBSERVATION

/

/1/5/

/D/ (28)

/0/7/9/ (29) /

NA ACTIVITY CONTENT RELEASED OF RELEASE AMOUNT OF ACTIVITY (35)

LOCATION OF RELEASE (36)

/1/6/

/Z/ (33)

/Z/ (34) /

NA

/

/

NA

/

PERSONNEL EXPOSURES NUMBER TYPE DESCRIPTION (39)

/1/7/ /0/0/0/ (37) /Z[ (38) /

NA

/

PERSONNEL INJURIES NUMBER DESCRIPTION (41)

/1/8/ /0/0/0/ (40) /

NA

/

LOSS OF OR DAMAGE TO FACILITY TYPE

DESCRIPTION

/1/9/

/Z[ (42) /

NA

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PUBLICITY ISSUED DESCRIPTION (45)

NRC USE ONLY

/2/0/

/Nf[ (44) /

NA

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W. R. CAR M HT PHONE (703) 894-5151

%106090 gFPREPARER

I e,

- o Virginia Electric and Power Company North Anna Power Station, Unit #2 Attachment: Page 1 of I Docket No. 50-339 Report No. LER 81-040/03L-0

Description of Event

On May 8,1981, while ramping down from 100% power for a scheduled outage, the core was borated to maintain rods high in the core. At 79%

power and decreasing, the Axial Flux Difference deviated greater than 5%

from the target band. A 28 minute penalty deviation was accumulated.

This event is contrary to T.S. 3.2.1 and reportable pursuant to T.S.

6.9.1.9.b.

Probable Consequences of Occurrence b.dce the indicated Axial Flux Difference remained within the limits shown on Figure 3.2-1, the health and safety of the general public were not affected.

Cause of Event

The Axial Flux Difference deviation was caused by the control rods

~ _ _ _ being~high in the core during the power reduction.

Immediate Corrective Action

Delta flux was returned within the target band by inserting the rods as the power reduction continued.

Scheduled Corrective Action There are no scheduled corrective actions required.

Actions Taken to Prevent Recurrence Importance of maintaining the Axial Flux Difference within the target band at all times will be re-emphasized during operator retraining.

Generic Implications There are no generic implications associated with this event.