ML19347F840

Updated LER 81-021/03X-1:on 810217,boron Injection Tank Was Found to Contain Boron Concentration Below Tech Spec Limit. Caused by Leak Past Check Valve 2-CH-155,located in Boric Acid Supply Line.Check Valve Will Be Replaced

ML19347F840
Person / Time
Site:	North Anna
Issue date:	05/20/1981
From:	Cartwright W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19347F838	List: ML19347F837 ML19347F840
References
LER-81-021-03X, LER-81-21-3X, NUDOCS 8105260443
Download: ML19347F840 (2)

Text

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{ UPDATE REPORT - PREVIOUS REP R DA G TORY COMMISSION LICENEEE EVENT REPORT CONTROL BLOCK / / / / / / / (1) (PLEASE PRINT Oh TYPE ALL REQUIRED INFORMAT7JN)

/0/1/ /V/A/N/A/S/2/ (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

/0/1/ /0/5/0/0/0/3/3/9/ (7) /0/2/1/7/8/1/

0 E LL/ (6) 9 (8) _ /0 /5 /2 /0 /8 /1/ (9)

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

/0/2/ / On February 17, 1981, while operating at 100% power, the Boron Injection Tank / .

/0/3/ / (BIT) was sampled and found to contain a boron concentration below-the /

/0/4/ / Technical Specification limit of 20,000 ppm. With the BIT only slightly below /

/0/5/ / the limit at 19,499 ppm boron it would still have performed its intended /

/0/6/ /- function, as a result the health and safety of the general public were not /

/0/7/ / affected. This event is reportable pursuant to T.S. 6.9.1.9.b. /

/0/8/ / /

SYSTEM 0 WSE CAUSE COMP. VALVE CODE f0DE SUBCODE COMPONENT CODE SUBCODE. SUBCODE

/0/9/ /S/F/ (11) /E/ (12) /B/ (13) /V/A/L/V/E/X/ (14) /C/_(15) g/ (16)

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

(17) REPORT NUMBER /8/1/ /-/ /0/2/1/ /\/ /0/3/ LX/

/-/ /1/

ACTION FUTURE EFFECT SHUTDOWN ATTACHMENT NPRD-4 PRIME COMP. COMPONENT TAKEN ACTION ON PLANT METHOD HOURS SUBMITTED FORM SUB. SUPPLIER MANUFACTURER g/ (18) /_C/ (19) g/ (20) LZ/ (21) /0/0/0/0/ (22) LY/ (23) LN/ (24) /N/ (25) /E/0/9/5/ (26)

CAUSE DESCRIPTION AND CORRECTIVE ACTIONS (27)

/1/0/ / Leakage past check valve 2-CH-155, located in the boric acid supply line to the/

/1/1/ / blender, allowed PG water to backflow and dilute the BIT via the recirc line. /

/1/2/ / Tank chemistry was restored by batching boric acid to "C" BAST.2-CH-155 will be/

/1/3/ / replaced following procurement of a suitable ' replacement valve, in the interim,/

/1/4/ / the backflow is being isolated by closing the upstream flow control valve. /

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

/1/5/ /JE/ (28) /1/0/0/ (29) / NA / ( 0) DISCOVERY LB/ (31) / Routine Sample Analysis /

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

/1/6/ [Z/ (33) [Z/ (34) / NA / / NA /

PERSONNEL EXPOSURES NUMBER TYPE DESCRIPTION (39)

/1/7/ /0/0/0/ (37) /ZL (38) / NA /

PERSONNEL INJURIES NUMBER DESCRIPTION (41)

/1/8/ /0/0/0/ (40) L 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 W. R. CARTWRIGHT PHONE _f703) 894-5151 81052604.43

-Virginia Electric and Power Company North Anna Power Station, Unit #2

Attachment:

Page 1 of 1 Dorkst No. 50-339 Report No.;LEP 81-021/03X-l' Description of Event On February 17, 1981, while operating at 100% power, the Boron Injection Tank (BIT) was sampled and found to contain less than the Technical Specifi-cation requirement of 20,000 ppa boron. Since the BIT is continuously recir-culated with the boric acid storage tanks,-the "C" storage tank was also out.

of spec. low on boron concentration. This event is contrary to T.S. 3.5.4.1.b and 3.1.2.8.a and reportable pursuant to T.S. 6.9.1.9.b.

Probable Consequences of Occurrence Tne boron injection tank contains a nominal 12-weight percent of concentrated boric acid solution (21,000 ppm boron) and is connected to the discharge of the centrifugal charging pumps. Upon actuation of a safety injection signal, the charging pumps -provide ~the pressure and flow capacity necessary to inject the boric acid solution into the Reactor Coolant System (RCS) when the BIT isolation valves open. To prevent cold spots and stratification of boric acid within the tank during normal operation, the contents of the boron _ injection tank are continuously recirculated with the-boric acid storage tanks via a boric acid transfer pump.

Cause of Event A leaking check valve in the boric acid supply line to the blender (2-CH-155) allowed blender primary grade (PG) water to backflow via the recirc line into the Boron Injection Tank diluting its contents.

Immedio e Corrective Action Boron Injection Tank chemistry was restored to within spec by-batching boric acid to its assigned Boric Acid Storage Tank ("C" BAST).

Scheduled Corrective Action A maintenance report has been submitted to replace check valve 2-CH-155 during a Mode 5 outage following the acquisition of an equivalent replacement valve. In the mean time, backflow of PG water into the BIT is being isolated by closing the boric acid flow control valve (FCV-2113A) directly upstream of the leaking check valve.

Actions Taken to Prevent Recurrence No further actions required.

Generic Implications There are no generic implicat.'.ons associated with this event.

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