ML19317G039

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RO-76-12:on 761007,reactor Taken Less than -1% Delta K/K Actual Shutdown W/Rcs Temp Less than 200 F,Creating Unsafe Condition.Caused by Personnel Error in Interpreting Shutdown Calculation.Calculation to Be Revised
ML19317G039
Person / Time
Site: Rancho Seco
Issue date: 10/18/1976
From: Colombo R
SACRAMENTO MUNICIPAL UTILITY DISTRICT
To:
Shared Package
ML19317F907 List:
References
NUDOCS 8002210741
Download: ML19317G039 (1)


Text

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UCENSEE EVENT REF.

CONTROL BLOCK:l l

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[PLEASE PRINT ALL REGUIRED INFORMATION)

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8 NE WYP V

UCENSE NUM8ER PE a1 lC l A l Rl Sl Sl 1l l0l0l-l0l010l0l0l-l0l0l l4 l1 l 1l ll 11 l0l1l 7 89 14 15 25 26 30 31 32 R1C CoCKET NUMBER EVENT cATE REPORT DATE CATEGORY TYPE O 1 CON'T l P l 0 l W y l0 l 5 l 0 l-l 0 l 3l 1l 2l l1 l0 l0 l 7 l 7l 6l l1 l0 l1 l8 l 7 l 6 l 7 8 57 58 59 60 61 68 69 74 75 80 EVENT DESCRPTION

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HE I On October 7,1976 the reactor was taken less than-1%Ak/k actual shutdown, with RCS l.

7 89 80 y 0

l temoerature less than 200*F.

This situation is outside the assumptions made in the l

7 89 80 3E l safety analysis for the eiected rod accident. At all ticies adecuate shutdown margin l 7 89 80 -

3E l existed, and boron iniection to-1%Ak/k shutdown was initiated immediately.

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7 89 80 EE l (RO-76-12) l -

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m CE CE COMPONENT CODE ACTURER VOLATON h lR lB l d l C l O l Nl R} O l D l lNl l Bl 0l 1l 5l lN l 7 89 10 11 12 17 43 44 47 48

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D CAUSE DESCRIPTION

@ l Technical Specifications do not prohibit this mode, however, it is an unsaf'e condition l,

7 89 80

  • UE l Direction will be given to not go less than 1%Ak/k shutdown unless approaching l

7 89 80 I 10 l criticality. An error in interpreting shutdown calculation led to the incident.

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'sE "c's$cvERY s power otsER status osCOVERY CESCRSTON '

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1 7 8 9

10 12 13 44 45 48 80 ACTMTV CONTENT AMOUNT OF ACTMTV LCCAJ oF RELEASE I

RELEASED OF RELEASE l y

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EE W

7 8 9

10 11 44 45 80-PERSONNEL EXPOSURES NUMBER TYPE CESCRIPTON DIE lel0l01 yl NA l

7 89 11 12 13 80.-

PERSONNEL INJURIES NUM8ER CESCRIPTON 3

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7 89 11 12 80 0FFSITE CONSEQUENCES E l Mfnf-n1 l '

to none.

7 89 80 [

LOSS OR DAMAGE TO FAC:LITY TYPE DESCArPTON f

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Z 7 89 10 80 PUBUClTY BE l Local newspapers notified October 13, 1976.

l 7 09 80

,,I ADDITIONAL FACT 0AS l Actual Shutdown calculation will be revised to better define what parameters mean.

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7 09 80 R. W. Colombo /F. T. Eisenhuth PHONE: (916) 452-3211 NAME:

spo ess.est i

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