05000339/LER-1980-037-31, /03L-0:on 800807,during Mode 3 Operation,Sample Analysis Indicated High Boron Concentration in SI Accumulators a & C.Caused by Stratification of Boric Acid in Makeup Source or Accumulators

/03L-0:on 800807,during Mode 3 Operation,Sample Analysis Indicated High Boron Concentration in SI Accumulators a & C.Caused by Stratification of Boric Acid in Makeup Source or Accumulators

ML19337A349
Person / Time
Site:	North Anna
Issue date:	09/05/1980
From:	Cartwroght W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19337A331	List: 05000339/LER-1980-037, Forwards LER 80-037/03L-0 05000339/LER-1980-037-31, /03L-0:on 800807,during Mode 3 Operation,Sample Analysis Indicated High Boron Concentration in SI Accumulators a & C.Caused by Stratification of Boric Acid in Makeup Source or Accumulators
References
LER-80-037-031-01, LER-80-37-31-1, N-80-090, N-80-90, NUDOCS 8009090584
Download: ML19337A349 (2)

LER-1980-037, /03L-0:on 800807,during Mode 3 Operation,Sample Analysis Indicated High Boron Concentration in SI Accumulators a & C.Caused by Stratification of Boric Acid in Makeup Source or Accumulators

Event date:
Report date:
3391980037R31 - NRC Website

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-.J hl U.S. NUCLEAR REGULATORY CCMMISSION LICENSEE EVENT REPORT f

i CCHTROL BLOCK / / / / / / / (1)

(PLEASE PRINT OR TYPE ALL REQUIRED INFORMATION)

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/V/A/N/A/S/2/ (2)

/0/0/-/0/0/0/0/0/-/0/0/ (3)

/4/1/1/1/1 (4)

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LICENSEE CODE LICENSE NUMBER LICENSE TYPE CAT

/L/ (6)

/0/5/0/C/0/3/3/9/ (7)

/0/8/0/7/8/0/ (8) / 0/ 9/ 0/ 5/ 8/ 0/ (9)

URCE DOCKET NUMBER EVENT DATE REPORT DATE EVEh7 DESCRIPTION AND PROBABLE CONSEQUENCES (10)

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On August 7,1980, during Mode 3 operation, sample analysis indicated a high

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boron concentration in both "A" and "C" SI accumulators. Both samples contained /

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2154 ppm boron which exceeds the 2100 ppm limit. Within 7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br />, the unit was /

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placed in a mode where the accumulators were not required, consequently the

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health and safety of the general public were not affected. This occurrence is /

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reportable pursuant to T.S. 6.9.1.9.b.

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SYSTEM

CAUSE

CAUSE COMP.

VALVE CODE CODE SUBCODE COMPONENT CODE SUBCODE SLTCODE

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/S/F/ (11) [X[ (12) LZL (13) /A/C/C/U/M/U/ (14) g/ (15) g/ (16)

SEQUENTIAL OCCURRENCE REPORT REVISION q

LER/R0 EVENT YEAR REPORT NO.

CODE TYPE NO.

(17) REPORT NUMBER

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ACTION FLTURE EFFECT SHUTDCWN ATTACHMENT NPRD-4 PRIME COMP. COMP 0 KENT 3

TAKEN ACTION ON PLANT METHOD HOURS SUBMITIED FORM SUB. SUPPLIER MANUFACTURER

/Y/ (18) [ZL(19) [CL(20) /Z/ (21) /0/0/0/0/ (22) [Y/ (23) /N/ (24) [JN (25) /D/1/0/0/ (26).

CAUSE DESCRIPTICN AND CORRECTIVE ACTIONS (27)

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The high sample concentrations are believed to have been caused by strati-

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fication of boric acid in either the makeup source (RWST) or the accumulators /

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themselves. The u:it was brought to a cold shutdown condition during which

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time attempts were rade to restore proper boron concentration by draining the /

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SI tanks and refilling from the RWST.

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FACILITY METHOD OF STATUS

% POWER OTHER STX"US

/ (3 ) DISCOVERY DISCOVERY DESCRIPTION (32)

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[B[ (23)

/0/0/0/ (29) /

NA [B[ (31)

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PERICDIC SAMPLING

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J ACTIVITY CONTENT RELEASED OF RELF.ASE AMOUNT OF ACTIVITY (35)

LOCATION OF RELEASE (36)

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G L (33)

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PERS0hNEL EXP"SURES NUMBER TYPE DESCRIPTION (39)

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PERSONNEL INJL' TIES NUMBER DESCRIPTION (41)

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LOSS OF CR DAMAGE TO FACILITY b3)

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DESCRIPTION

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PUBLICITY ISSUED DESCRIPTION (45)

NRC USE ONLY

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NAME OF PREPARER W. R. CART 4RIGHT PHONE (703) 394-5151 U"9090$&

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Virginia Electric and Power Company

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North Anna Power Station, Unit 92 Attachment: Page 1 of 1 Docket No. 50-339 Report No. LER 80-037/02L-0 1

Description of Event

12 On August 7,1980, with the unit in Mode 3, sample analysis of "A" acd "C" SI accumulators indicated a boron concentration in excess of the 2100 ppe Technical Specification ihait. Both accumulator samples contained 2154 ppa boron. This occurrence is reportable pursuant to T.S. 6.9.1.9.b.

Probable Consequecces of Event The operability of each RCS accumulator ensures that a sufficient volume of borated water will be immediately forced into the reactor core '

through each of the cold legs in the event the RCS pressure falls below' the pressure of the accumulators. This initial surge of water into the core provides the initial cooling mechanism during large RCS pipe ruptures.

The cencentration of boric acid in the RCS accuculators is maintained within an operating band of 1500 o 2100 ppe boron. 3ecause within 7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br /> the unit was placed in a mode of operation where the accumulators were not required, the health and safety of the general public were not affected.

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Cause of Event

The high boron coper;'. ration in the "A" and "C" accumalator samples is believed to have caen caused by stratification of boric acid in either the water aa'seup source (RWST) or the accumulators themselves.

Immediate Correestve Action The unit was brought to a cold shutdown condition.

Scheduled Corrective Action The chemistry of the SI accumulators was restored to within speci-fications prior to reentry into Mode 4.

Actions Taken to Prevent Recurrence An evaluation to prevent recurrance is underway.

Generic Implications e

This problem is generic in nature in that borated water tanks are always susceptable to stratification when not adequately recirculated on a continuous basis.

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