ML20023E072

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LER 83-029/03L-0:on 830509,following Rapid Rampdown from 100% to 4% power,I-131 Dose Equivalent Exceeded 1.0 Uci/G. Caused by Unidentified Fuel Element Defect Worsened by post-rampdown Conditions.Sampling increased.W/830526 Ltr
ML20023E072
Person / Time
Site: North Anna Dominion icon.png
Issue date: 05/26/1983
From: Harrell E
VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To: James O'Reilly
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
LER-83-029-03L-01, LER-83-29-3L-1, N-83-067, N-83-67, NUDOCS 8306070173
Download: ML20023E072 (4)
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, U.S. NUCLEAR REGULATORY COMMISSION LICENSEE EVENT REPORT CONTROL BLOCK / / / / / / / (1) (PLEASE PRINT OR TYPE ALL REQUIRED INFORMATION)

/0/1/ /V/A/N/A/S/1/ (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 OUR n / (6) /0/5/0/0/0/3/3/8/ (7) /0/5/0/9/8/3/ (8) / 0/ S/ 2/ 6/ 8/ 3/ (9)

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

/0/2/ / On May 9, 1983, following a rapid rampdown from 100% to 4% power, the I-131 Dose /

/0/3/ / Equivalent exceeded 1.0 micro Ci/ gram. The first sample to exceed the limit was /

/0/4/ / taken 1 1/2 hours after the rampdown. Samples were taken at least every four /

/0/5/ / hours in accordance with Item 4a of Technical Specification Table 4.4-4. The /

/0/6/ / level returned to less than the limit within 19 hours2.199074e-4 days <br />0.00528 hours <br />3.141534e-5 weeks <br />7.2295e-6 months <br />; therefore, the public /

/0/7/ / health and safety were not affected. This event is reportable pursuant to T.S. /

/0/8/ / 6.9.1.9.d and T.S. 6.9.2. /

SYSTEM CAUSE CAUSE COMP. VALVE CODE CODE SUBCODE COMPONENT CODE SUBCODE SUBCODE

/0/9/ /R/C/ (11) /X/ (12) /Z/ (13) /Z/Z/Z/Z/Z/Z/ (14) /Z/ (15) /Z/ (16)

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

(17) REPORT NLHBER /8/3/ /-/ /0/2/9/ /N / /0/3/ /L/ /-/ /0/

ACTION FUTURE EFFECT SHUTDOWN ATTACHMENT NPRD-4 PRIME COMP COMPONENT TAKEN ACTION ON PLANT METHOD HOURS SUBMITTED FORM SUB. SUPPLIER MANUFACTURER

/X/ (18) /Z/ (19) /Z/ (20) /Z/ (21) /0/0/0/0/ (22) /Y/ (23) /Y/ (24) /N/ (25) /W/1/2/0/ (26)

CAUSE DESCRIPTION AND CORRECTIVE ACTIONS (27)

/1/0/ / This event was caused by a fuel element defect, though not specifically identi- /

/1/1/ / fled, in the reactor core. Post rampdown conditions in the core enhanced the /

/1/2/ / release of fission fragments to the Reactor Coolant System which caused the /

/1/3/ / iodine spike. The accelerated sampling frequency of T.S. 3.4.8 was implemented /

/1/4/ / until RCS specific activity returned to less than the limit of T.S. 3.4.8.a. /

FACILITY METHOD OF STATUS  % POWER DISCOVERY DISCOVERY DESCRIPTION (32)

/1/5/ /X/ (28) /0/0/4/ (29) / OTHER NA STATUS (

/ /C/ (31) / Chemistry Sample /

ACTIVITY CONTENT l RELEASED OF RELEASE AMOUNT OF ACTIVITY (35) LOCATION OF RELEASE (36) l

/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 /

PUBLICITY ISSUED DESCRIPTION (45) NRC USE ONLY

/2/0/ /N/ (44) / NA /////////////

NAME OF PREPARER E. Wayne Harrell PHONE (703) 894-5151 8306070173 830526 gDRADOCK05000g 7gg

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4 Yb vlRGINI A ELECTRIC AND POWER COMP ANY /

NORTH ANN A POWER ST ATION P.O. BOX 402 / de MINER AL, VIRGINI A 23117 v

@0 May 26, 1983 Mr. James P. O'Reilly, Regional Administrator Serial No. N-83-067 U. S. Nuclear Regulatory Commission N0/WFS: 11 Region II Docket No. 50-338 101 Marietta Street, Suite 2900 Atlanta, Georgia 30303 License No. NPF-4

Dear Mr. O'Reilly:

Pursuant to North Anna Power Station Technical Specifications, the Virginia Electric and Power Company hereby submits the following License Event Report applicable to North Anna Unit No. 1.

Report No. Applicable Technical Specifications LER 83-029/03L-0 T.S. 6.9.1.9.d, 6.9.2 This report has been review 9.d by the Station Nuclear Safety and Operating Committee and will be forwarded to Safety Evaluation and Control for their review.

Very Truly Yours, f A E. Wayne Harrell

% Station Manager Enclosures (3 copies) cc: Document Control Desk (1 copy) 016 Phillips Bldg.

U.S. Nuclear Regulatory Commission Washington, D. C. 20555 w.e %?

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i Virginia Electric and Power Company North Anna Power Station, Unit-No,'l

Attachment:

Page 1 of 2 Docket No. 50-338 .

Report No. LER 83-029/03L-0 4 N, Description of Even't- '~

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On May 9,1983, following rapid .rampdown,' form 100% to 4% power, the c , >

specific activity ofsthe reactor. coolant ~ exceeded 1.0; micro Ci/ gram.

The first primary coolant sample to ' excee'd the limit was taken ,-

approximately 1 1/t houri af ter the rampdown and indicated a level of' 4

1.92 micro Ci/ gram. -Subsequent samples , vere taken at least every four s qs

+ -hours!in accordance'with Item 4a of T.S. Table 4.4-4., '

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Probable Consequences of Occurrence s

., Since the Dose Equivalent.1-1M limit was exceeded for a short s period of time, <19 hours, gud the I-131 Iceel was monitored by sampling

-  ;' a t least every A ehours"until the I-131 level returned to less than the s

3T.S.3.4.8limitMie{fEbQchealthandsafetywerenotaffected.

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,,]ftuseofEvent

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$ The . iodine spike' wg cau' sed by increised fuel ourgassing- from a 4

, fuel, defect, though,not spo,cifically identified, after a rapid rampdown 3 from 100% to 4% power. c  %'

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,. 1mmediate Corrective Action .

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The primary coolant was sampled ' and analyze at the ' frequency $

s required by item 4a of Technical Specifications Table 4.4-4. The 1 specific activity was verified to be less than 1.0 minro C1/gt m within' s i 19 hours2.199074e-4 days <br />0.00528 hours <br />3.141534e-5 weeks <br />7.2295e-6 months <br />. '

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Scheduled Corrective Action -

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No further action is required.

Actions Taken to Prevent Recurrence No further action is required.

Generic implications There are no generic act' ions associated with this event.

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Attachment:

Page 2 of 2 Sypplemeht_al-Information x , u x ..

This event is reportable as a " Thirty-Day Written Report" pursuant 4

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to T.S. 6.9.1.9.d. In addition the supplemental information required by 4" a w T.S. 6.'9.'2 "Special Report" and by T.S. 3.4.8 is included as follows:

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1. , " Reactor Power History 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> prior to the first sample in

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(L \ which the limit was exceeded, s

May 9, 1983 - 15 hours1.736111e-4 days <br />0.00417 hours <br />2.480159e-5 weeks <br />5.7075e-6 months <br /> at 100% RTP

\}' May 8, 1983 - 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> at 100% RTP L

May 7, 1983 - 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> at 100% RTP c h

2. Fuel Burnup by Core Region - As of May 9, 1983:

. Fuel Batch 4 - 27,417 MWD /MTU 5 - 16,957 MWD /MTU 6- 2,260 MWD /MTU Cycle 4 Burnup - 2,077 MWD /MTU

3. Normal mixed bed demineralization operation 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> prior to and after the event. Average flowrate of 120gpm.
4. No de-gassing operations were performed.
5. Duration of I-131 spike DATE TIME DOSE EQUIVALENT I-131 (Micro Ci/gr)

May 9, 1983 1800 1.92 bby 9, 1983 2057 2.25 bby 9, 1983 2200 1.89 May 10, 1983 0000 1.69 May 10, 1983 0203 1.66 May 10, 1983 0400 1.07 May 10, 1983 0730 1.69 May 10, 1983 0945 1.24 May 10, 1983 1300 .89

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