05000339/LER-1981-042-03, /03L-0:on 810522,boric Acid Storage Tank Concentration Was Below Required Limit.Caused by Blender Valve FCV-2113A Mistakenly Being Operated in Auto Allowing Water to Backflow Into Sys.Tank Concentration Restored

/03L-0:on 810522,boric Acid Storage Tank Concentration Was Below Required Limit.Caused by Blender Valve FCV-2113A Mistakenly Being Operated in Auto Allowing Water to Backflow Into Sys.Tank Concentration Restored

ML19350F063
Person / Time
Site:	North Anna
Issue date:	06/18/1981
From:	Cartwright W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19350F060	List: 05000339/LER-1981-042, Forwards LER 81-042/03L-0 05000339/LER-1981-042-03, /03L-0:on 810522,boric Acid Storage Tank Concentration Was Below Required Limit.Caused by Blender Valve FCV-2113A Mistakenly Being Operated in Auto Allowing Water to Backflow Into Sys.Tank Concentration Restored
References
LER-81-042-03L, LER-81-42-3L, NUDOCS 8106240153
Download: ML19350F063 (2)

LER-1981-042, /03L-0:on 810522,boric Acid Storage Tank Concentration Was Below Required Limit.Caused by Blender Valve FCV-2113A Mistakenly Being Operated in Auto Allowing Water to Backflow Into Sys.Tank Concentration Restored

Event date:
Report date:
3391981042R03 - NRC Website

text

<-

r U.S. KUCLEAR REGULATORY LOMMISSION ggg LICENSEE EVENT REPORT CONTROL BLOCK / / / / / / / (1)

(PLEASE PRINT OR TYPE ALL REQUIRED INFORMATION)

/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

/L/ (6)

/0/5/0/0/0/3/3/9/

(7)

/0/5/2/2/8/1/

(8) /g/c/ 1 g/g/y/ (9)

/

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

/0/2/

/ On May 22, 1981, while operating at 100% power. daily sample analysis of the

/

/0/3/

/ Unit's boric acid storage system ('C" BAST) identified a low boron concentration /

/0/4/

/ of 19,511 ppm.

T.S. 3.1.2.8.a.2 requires a minimum tank concentration of 20,000 /

[0/5/

/ ppm boron in Modes 1 thr, 4.

With the boric acid storage tank chemistry only

/

/0/6/

/ slightly below the limit, the required capability for reactor control was still /

/0/7/

/ available. As a result, the health and safety of the general public were not

/

/0/8/

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

/

SYSTEM

CAUSE

CAUSE COMP.

VALVE CODE CODE SUBCODE COMPONENT CODE SUBCODE SUBCODE

/0/9/

/R/B/ (11) [A[ (12) /A/ (13) /V/A/L/V/E/X/ (14)

/F/ (15)

/G/ (16)

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

CODE TYPE NO.

(17) REPORT NUMBER

/8/1/

/-/ /0/4/2/

/\\/

/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) /N/ (24) /N/ (25) /M/1/2/0/ (26)

CAUSE DESCRIPTION AND CORRECTIVE ACTIONS (27)

/0/

' Blender valve FCV-2113A was temporarily operated in " Auto" due to a misunder-

/

'(*_

standing that the leaking downstream check valve had been replaced during the May/

/1/2/

/ outage (See LER 81-021).

This action allowed PG water to,b_ackflow through the

/

/1/1/

/ check valve into the boric acid system. Tank chemistry was restored by batching /

/1/4/

/ to "C" BAST and a standing order to operate with FCV-2113A closed was issued.

/

FACILITY METHOD OF STATUS

% POWER OTHER STATUS DISCOVERY DISCOVERY DESCRIPTION (32)

/1/5/

LE[ (28)

/1/0/0/ (29) /

NA

/ (30) [BL (31) / ROUTINE SAMPLE ANALYSIS /

ACfIVITY CONTENT RELEASED OF RELEASE AMOUNT OF ACTI<ITY (35)

LOCATION OF RELEASE (36)

/1/6/

/Z/ (33)

/Z/ (34) /

NA

/

/

NA

/

FERSONNEL EXPOSURES SUMBER TYPE DESCRIPTION (39)

/1/7/ /0/0/0/ (37) [?[ (38) /

NA

/

PERSONNEL INJURIES NUMBER DESCRIPTION (41)

/1/8/ /0/0/0/ (40) /

NA

/

LOSS OF OR DAMAGE TO FACILITY ( )

TYPE

DESCRIPTION

f 1/9/

/Z/ (42) /

NA PUBLICITY ISSUED DESCRIPTION (45)

. ti:

^NLY

/2/0/

/N/ (44) /

NA

/////

?!AME OF PREPARER N. 3.

' ~ =. I. "

C

, 594-5151 8loe24.0/53

f Virginia Electric and Power Company North Anna Power Station, Unit 2 Attachment: Page 1 of 1 Docket No. 50-339 Report No. LER 81-042/03L-0

Description of Event

On May 22, 1981, while operating at 100% power, the unit's boric acid storage system ("C" Boric Acid Storage Tank) was sampled and found to contain a boron concentration of 19,511 ppm. This value is contrary to T.S. 3.1.2.8.a.2 which requires the borated water source to contain a minimum of 20,000 ppm boron in Modes 1 thru 4.

Af ter approximately 5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br />, sample analysis indicated an acceptable concentration of boron which cleared the 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> Action Statement.

It now appears that this was an unrepresentative sample since subsequent analysis 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> later showed tank boron concentration to still be low at 19,888 ppm. The applicable Action Statement was once again re-entered for an additional 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> until proper chemistry was restored by batching boric acid to the tank. This event is reportable pursuant to T.S. 6.9.1.9.b.

Probable Consequences of Occurrence Proper boric acid storage system chemistry ensures that suff'.cient negative reactivity control is available during each mode of facility operation. Because the boron concentration of the boric acid storage tank was only slightly below the limit at 19,511 ppm, adequate capability for reactor control still existed. Therefore, the health and safety of the general public were not affected.

Cause of Event

Boric acid blender flow contr21 valve FCV-2113A was temporarily operated in " Auto" (opened) due to a misunderstanding that the leaking downstream check valve (2-CH-155) had been replaced during the past May outage (refer to LER 81-021). This action allowed primary grade water to backflow through the check valve into the boric acid system.

Immediate Corrective Action

Boric acid was batched to "C" Boric Acid Storage Tank until tarr chemistry was restored to within spec.

Scheduled Corrective Action Cher~. valve 2-CH-155 will be replaced following the acquisition of a suitable replacement valve.

Actions Taken to Prevent Reccurrence Standing Order No. 80 has been issued to operate with blender flow contro: valve FCV-2113A in the closed position until a replacement check valve for 2-tn-155 is procured and installed.

Generic Implications There are no generic implications associated with this event.

's