05000281/LER-1978-038-03, /03X-1 on 781030:boric Acid Flow from Boric Acid Tank to Blender Was Interrupted.Caused by Blockage of Crystallized Boron at Elbow in Line 1-CH-356-152

/03X-1 on 781030:boric Acid Flow from Boric Acid Tank to Blender Was Interrupted.Caused by Blockage of Crystallized Boron at Elbow in Line 1-CH-356-152

ML18113A869
Person / Time
Site:	Surry
Issue date:	02/20/1979
From:	Baucom T VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML18113A867	List: 05000281/LER-1978-033-03, /03X-1 on 780926:circulating Water Outlet Valve MOV-CW-200D Failed to Close When Operated Electrically. Caused When Actuator Cam for Shut Torque Switch Became Wedged Against Torque Switch Hold Down Screw 05000281/LER-1978-038-03, /03X-1 on 781030:boric Acid Flow from Boric Acid Tank to Blender Was Interrupted.Caused by Blockage of Crystallized Boron at Elbow in Line 1-CH-356-152 ML18113A866
References
LER-78-038-03X-01, LER-78-38-3X-1, NUDOCS 7902260476
Download: ML18113A869 (2)

LER-1978-038, /03X-1 on 781030:boric Acid Flow from Boric Acid Tank to Blender Was Interrupted.Caused by Blockage of Crystallized Boron at Elbow in Line 1-CH-356-152

Event date:
Report date:
2811978038R03 - NRC Website

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LICENSEE EVENT REPORT CONTROL BLOCK: 1

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I During normal operation with the unff at 100% power, it was discovered that the I boric acid flow from the boric acid tanks to the blender was interrupted.

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The health and safety of the public were not affected*.

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~Jrry Power Station, Unite Docket No: 50-281 Report No: 78-038/X-l Event Date:

10-30-78 Boric Acid F~ow Path Blockage

1.

Description of Event

While atte~pting normal blending action, the control room meter, monitored by the operator, indicated a no flow condition existed in a line leading to the blender.

This situation is contrary to Technical Specification 3.2.c.4 which requires two (2) flow paths to the core when the unit is critical.

The* event is reportable in accordance with Technical Specification 6.602.b.(2).

2.

Probable Consequences/Status of Redundant Systems During this period, a redundant flow path to the core from the refueling water storage tanks was available, therefore the health and safety of the public were not affected.

3.

Cause

Upon investigation, it was discovered that the line had become plugged with a crystallized mass of boron which had apparently built up over a period of time at an elbow in the line.

4.

Immediate Corrective Action

A Maintenance Report was initiated to rectify the flow loss, and the obstruction was dislodged, allowing flow to return to normal.

While the problem was being rectified, rampdown of the reactor was commenced and continued until flow was again established, at which time power was escalated, It was determined that the heat tracing had been functioning within the lirr.its required both prio~ to removal of the blockage and once the problem was resolvedo

5.

Scheduled Corrective Action:

None

6.

Action Taken to Prevent Recurrence:

Administrative controls have been established requiring blending action periodically, to assure flow in the system.

7.

Generic Implications:

Historically, similar flow restrictions have been ra~1domly e...-...::perienced on both units.