05000366/LER-1980-091-03, /03L-0:on 800605,while Pulling Rods to Increase Power,Level Core Max Fraction of Limiting Power Density Found Higher than Tech Spec Allowed.Caused by Combination of Low Feedwater & Low Xenon.Nrc Reviewed Problem

/03L-0:on 800605,while Pulling Rods to Increase Power,Level Core Max Fraction of Limiting Power Density Found Higher than Tech Spec Allowed.Caused by Combination of Low Feedwater & Low Xenon.Nrc Reviewed Problem

ML19329F984
Person / Time
Site:	Hatch
Issue date:	06/30/1980
From:	Coggin C GEORGIA POWER CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19329F977	List: 05000366/LER-1980-091, Forwards LER 80-091/03L-0 05000366/LER-1980-091-03, /03L-0:on 800605,while Pulling Rods to Increase Power,Level Core Max Fraction of Limiting Power Density Found Higher than Tech Spec Allowed.Caused by Combination of Low Feedwater & Low Xenon.Nrc Reviewed Problem
References
LER-80-091-03L, LER-80-91-3L, NUDOCS 8007110437
Download: ML19329F984 (2)

LER-1980-091, /03L-0:on 800605,while Pulling Rods to Increase Power,Level Core Max Fraction of Limiting Power Density Found Higher than Tech Spec Allowed.Caused by Combination of Low Feedwater & Low Xenon.Nrc Reviewed Problem

Event date:
Report date:
3661980091R03 - NRC Website

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EVENT DESCnlPTION AND PROBA C SE NCES E 10n 6-5-80, while pulling rods to increase power it was determined that l

l E lthe CFMLPD was.625 while reactor power was 51%.

Corrective action was l E ltaken within 15 minutes, but et the end of 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> the peaking was stilll E Itoo high to allow adjustment of the APRMs.

This is a repetitive occur-l E Irence.

See LER #50-366/1980-075.

There were no effects upon public'

._J E lhealth and safety due to this event.

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47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h E IThe unusually high peaking was caused by a combination of low feedwater l E l temp and low xenon.

As normal corrective action did not reduce it with-i i

to 25%

i g l n the 2-hour limit, power was reduced to less than or equal E lwithin 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />.

Appropriate members of the reactor engineering staff l

E 1 ave reviewed the event for familiarity.

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50-366/1980-091 Licensee:

Georgia Power Company Facilit.y Name:

Edwin I.

Hatch Docket #:

50-366

Narrative

Report for-LER 50-366/1980-091 On 6-5-80',

while pulling ro'ds to increase power a it a power level' of 51%

t.h e '. p ro c e s s computer core performance program (P1) ' ind ica t.ed t.h a t.

the core maximum fraction of limiting power ~ d e n s i t.y wa s - 0. 6 2 5.

Per. Tech Specs 3.2.2 t. h e required ac t. ion - wa s '. taken _ t. o c i t.h e r reduce t.h e CMFLPD or adjust the APRMs.

- The unusually : high peaking being experienced resulted from a combinat. ion of_ low feedwater t. cmp e r a t u r e ( t.h e heaters were out for maintenance) and the low xenon concentration.

Normal corrective actions taken were - uns ucces s f ul, and a'

the end of t.h e.t.wo-hour ' limit the CMFLPD was still too high to allow ad j u s tmen t. 'o f t. h e APRMs and still maintain an adequate margin to the neutron' monitoring system trip.

A t.

f. h e - e n d of t. h e - t.w o -h o u r lim i t.

a deviation was w r i t t. e n, and p r e p a r a t. i o n s -

t. o have t. h e un i t.

a t.

less than or equal to 25%

power w i t.h i n t.h e n e x t.~

four hours were begun.

By the end of the four-hour. limit.

reactor power had ~been reduced by flow reduction and-rod insertion to less-than 25%.

Altpr reviewing the problems t.h a t Nad been experienced with the - rod p a t. t. c r n,

mo d i f i c a t. i o n s were made to the withdrawal sequence which would - suppres s -the peaking areas.

Subsequent to pulling t.o this new. p a t. t. c r n calculations showed-t.h a t t. h e.

peaking problem had been reduced and normal s t. a r t u p c o n t. i n u e d.

Appropriate members of_ the r e a c t.o r engineering staff have-rev iewed - t.he incident' and plan _to use modified rod p a t. t. c r n s if starting up in similar c o n d i t. i o n s in the future.

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