05000368/LER-1980-067-03, /03L-0:on 800823,during Mode 1 Operation I-131 Dose Equivalent Value of 3.6 Uci Was Observed.Caused by Crud Burst.Rcs Letdown Flow Was Increased & I-131 Decreased to 0.26 Uci

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/03L-0:on 800823,during Mode 1 Operation I-131 Dose Equivalent Value of 3.6 Uci Was Observed.Caused by Crud Burst.Rcs Letdown Flow Was Increased & I-131 Decreased to 0.26 Uci
ML19338D786
Person / Time
Site: Arkansas Nuclear Entergy icon.png
Issue date: 09/16/1980
From: Penderqraft R
ARKANSAS POWER & LIGHT CO.
To:
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML19338D783 List:
References
LER-80-067-03L, LER-80-67-3L, NUDOCS 8009230748
Download: ML19338D786 (5)
v • d • e


LER-1980-067, /03L-0:on 800823,during Mode 1 Operation I-131 Dose Equivalent Value of 3.6 Uci Was Observed.Caused by Crud Burst.Rcs Letdown Flow Was Increased & I-131 Decreased to 0.26 Uci
Event date:
Report date:
3681980067R03 - NRC Website
v • d • e

text

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O NRC FORM 366 U. S. NUCLE AR REGULATORY COMMISSION 1.lCENSEE EVENT REPORT EXHIBIT A CONTROL 8 LOCK: l l l 1 I l.lh (PLE ASE PRINT OR TYPE ALL REQUIRED INFORMAf TON) 8 I A]R l Al N;0l p [gl 0 j0 l -l0 l 0 [ 0l 0l 0 l-l 0 l0 lgt l1 l 1l1 l 1lgl l lg 3

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EVENT DESCRIPitON AND PROS AOLE CONSEQUENCES h F6TD I During mode one coeration. with nower escalatinn in nrogrpss. an Indinn-1 BTil I 131 dnco onnivalent valvo of 16 micrncnrips nor nram wac nheervod; I

f 6Til l ovcondinn the limite nf Toch _ 9nne. 14_A_a Thic necurronce le IoisiIsimilar to LER 50-368/80-009 Renortablo Por Toch. Spoc. 6.9.1.9 h.

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)b 36 33 go el og 43 gg 43 CAUSE DESCRePTION AND CORRECHVE ACTIONS h ISee attachment labled "LER 50-368/80-067 Summary".

Per the requirement i

i o rrrr1 lof T.S.3.4.8.d., information regarding history of (1) reactor power.

I 1/2) fuel burneo. (3) cleanuo flow. (4) degassing ooeration. and (5) time i i.

E Iduration is also att@d.

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LER 50-368/80-067 CUMMARY The Unit had just reached 100% full power following a reactor trip (Iodine - 131 activity following the trip was 0.688 micro-curie per gra;n).

RCS letdown flow was increased and a four hour RCS Iodine sample frequency was initiated following the high RCS Iodine activity discovery. The first sample (four hour sample) reve-led a remarkable decrease in Iodine - 131 activity from 3.6 microcurie per gram to 0.26 microcurie per gram. All power changes made during the power escalation were within the operating guidelines, however power escalation was greater than 20% per hour which is faster than previous startups.

This sharp decrease in Iodine activity coupled with the high gross RCS activity discovered during the initial RCS sample, indicates a " CRUD" burst took place rather than fuel failurer.

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Attachment to LER 50-368/80-067 i

Items 1 & 3 Reactor Power and Cleanup Flow History starting 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> prior to sample.

DATE TIME Rx POWER (%)

CHRG FLOW (GPM)

LD FLOW (GPM) 8/21/80 1000 99.58 46 36 1100 100.02 46 39 1200 99.63 46 43 1300 100.02, 46 41 1400 100.08 46 39 t

1500 99.20 46-39 1600 63.19 46 36 s

1700 60.37 89 56

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1800 i [ ' '\\

61.04 89 55 64.80 s

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,3 2000' N

68.39 'i 89 98 2100 5

90.58 89 98 s

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2200 /

90.39 89 99

2300, 0.00 131 34 it '

8/22/80

.Q00dl' O.00 87 101

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0100 0.00 87 91 0200 0.00 87 86

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0300 0.00 87 78 s

1 0400

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0.00 87 80 0500' O.00 87 80 0600-0.00 87 69 s-0700 0.00 87 78

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Attachmmnt.to LER 50-368/80-067 DATE TIME Rx POWER (%)

CHRG FLOW (GPM)

LD FLOW (GPM) 8/22/80 1100

'O.00 45 38 1200 0.00 45 37 1300 0.00 106 38 1400 0.00 45 35 1500 0.00 45 0

1600 0.00 45 0

1700

- 0.00 45 0

1800 0.00 45 0

1900 0.00 45 0

2000 0.00 45 0

2100 0.00 45 0

2200 0.00 45 0

2300 0.00 45 0

8/23/80 0000-0.00 86 0

0100 18.88 84 0

0200 36.55 82 0

0300 61.19 82 0

0400 76.16 82 0

0500 77.18 82 0

0600-

'84.95-82 0'

0700 91.29 82 0

0800 91.20 46 0

0900:

93.98 46 0

1000 98.26

- 46 0

s..

1100 100.01 46 0

  • NOTE: No ;1og/ Record / Indication of any bypass to Vac Degas System a

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Attechment to

.x 50-368/80-067 Item 2: Regional Burnup Total Burnable Burnable of Poison Poison Average Fuel Type of F.A.'s Enrichment Shims B10"!

3959.9 MWD /MTU A

61 1.93 0

B+

60 2.27 12 3.62 5424.2 MWD /MTU C

8 2.94 12 1.18 6241.9 MWD /MTU y

C 16 2.94 12 1.96 7283.9 MWD /MTU 2

C 12 2.94 2

3.62 7802.0 MWD /MTU 3

C 16 2.94 3

3.62 7531.3 MWD /MTU 4

C 4

2.94 12 1.96(9) 4067.9 MWD /MTU 5

3.62(3)

Item 4: No degassing was done within 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> prior to the sample exceeding the limit nor afterward until returning within allowable limits.

Item 5: The duration with activity > 1.0 pCi/gm was apparently less than 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />.

A sample of reactor coolant was taken during power ascension at 1050 hours0.0122 days <br />0.292 hours <br />0.00174 weeks <br />3.99525e-4 months <br /> on 8/23/80 which showed *he I131 dose equivalent activity to be at 3.6 pCi/cc. A 131 dose second sample was taken at 1400 hours0.0162 days <br />0.389 hours <br />0.00231 weeks <br />5.327e-4 months <br /> on 8/23/80 which showed that the I equivalent had dropped to 0.26 pCi/cc. Due to the nature of the sample results (that is short duration spike and high gross activity occurring concurrently),

we conclude that this event was a crud burst and not a fuel failure.

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