ML20128C631

Confirms Telcon Re Critical Rod Position Anomalies Discussed in Ltrs of 920203 & 920229

ML20128C631
Person / Time
Site:	Monticello
Issue date:	03/15/1972
From:	Richings H US ATOMIC ENERGY COMMISSION (AEC)
To:	US ATOMIC ENERGY COMMISSION (AEC)
References
NUDOCS 9212040492
Download: ML20128C631 (1)

Text

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i March 15, 1972 j it non TO rrhrs TE12 PHONE CAIL FRCH G.E. RE MONTICIILO - REACTIVITY ANOMALY J

As a result of a conversation between D. Knuth and Ivan 8tuart of 4 0.E. at the last ACRS meeting, a call was received by D. Knuth on March 9 frce W. Gilbert of 0 E. on the subject of critical rod position anomalies discucced in the letters of February 3 and February 29 from Monticello. I was a party to the telephone con-

! versation. The primary question which had been raised by (but not i discussedin)theseletterswaswhetherthehigherthananticipated

!' flux peaking in the water channelc, which was indicated as being the cause of the more rapid burnout of the poison curtains, also implied l greater power peaking in the edge fuel pins. 0E.'s(Oilbert's) answer to this was no. They said the flux peaking vac not a surprise.

They had known about it at the design stage and had used empirical i

corrections for the fuel power peaking, but not having empirical factors for the poison curtains they %d increased the hurtain boron loading, resulting in increased shutdown margin. Furthermore, they said the never calculational models correctly accounted for gap peak-ing and that experimental gamma scans had confinned the correctness of the calculations.

The subject of reactivity coefficients was not discussed during the

phone cal.1 but subsequent to the call I read the Compliance February monthly report (and since determined that a more detailed individual

l. Monticello report is not in as yet) and it indicates a much larger

reacitvity anomaly than had been implied by the Monticello letters.

l This would seem to indicate that the error in the reactivity coeffi-cient was more important than had been implied by the letters. ,

Assuming 0.E.'s answers are correct and they can calculate correctly now, at best all this once again demonstrate 0.E.'s failure to communi.

cate in timely fashion with us (or in this case apparently with Monti-cello) and points out the need for much more coorplete and detailed and up to date SARs.

Distribution: Howard J. Richings Supp14 (g Electrical, Instrumentation, and Control DR Reading Systems Branch EICSB Reading Division of Reactor Standards er. n rou n ; nam S DRS:EICSF 1 omcc > .g/....E6'MsW'W' Moore, Dh - ' ' ' ~ ~ ~ ~ ~ - ' ' ~ ~ - -

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Foren AEC-lit (Rev.9 53) AECM O& p, s. oovannutxt n:wToea orries : 1.to o . ens.s s 9212040492 720315 PDR ADOCK 05000263 P PDR

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