05000280/LER-1979-030-01, /01T-0:on 791029,radiation Alarm Setpoint Component Cooling Sys Found Greater than Two Times Background.Caused by Improper Setting of Alarm Setpoint.Vent Valve Manually Isolated

/01T-0:on 791029,radiation Alarm Setpoint Component Cooling Sys Found Greater than Two Times Background.Caused by Improper Setting of Alarm Setpoint.Vent Valve Manually Isolated

ML18136A184
Person / Time
Site:	Surry
Issue date:	11/09/1979
From:	Stewart W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML18136A183	List: 05000280/LER-1979-030, Forwards LER 79-030/01T-0 05000280/LER-1979-030-01, /01T-0:on 791029,radiation Alarm Setpoint Component Cooling Sys Found Greater than Two Times Background.Caused by Improper Setting of Alarm Setpoint.Vent Valve Manually Isolated
References
LER-79-030-01T, LER-79-30-1T, NUDOCS 7911140365
Download: ML18136A184 (2)

LER-1979-030, /01T-0:on 791029,radiation Alarm Setpoint Component Cooling Sys Found Greater than Two Times Background.Caused by Improper Setting of Alarm Setpoint.Vent Valve Manually Isolated

Event date:
Report date:
2801979030R01 - NRC Website

text

NRC FORM 366 ii-'17).._

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0'Tith the unit at 100% power the Radiation Alarm Setpoint for the Component Cooling

[£]TI I System was found to be greater than two times background as listed in Technical oo:TI !Specification 3.7, Table 3.7-5.

This event would have caused the surge,tank vent [ill] 1valve of the Component Cooling System not to close automatically at twice the

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!background level.

Since vent valve isolation was not required, the health and

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1safety of the general public were not affected.

[QJ]J !Technical Specification 6.6.2.a.

This event is reportable per 7

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42 43 44 47 [III] I The initial corrective action taken was to isolate the surge tank vent valve [IJJJ I manually and determine a background radiation level.

New alarm and alert setpoints [III] I were then set on both monitors.

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Stewart PHONE:80't 357 3184

e Attachment, Page 1 Surry Power Station, Unit 1 Docket No.: 050-0280 Report No.: LER 79-030/0lT-0 Radiation Monitor (RH-CC-105/ 106) Setpoint Alarm Improperly Set

1.

DESCRIPTION OF EVENT

With the unit at 100% power, the Radiation Alarm Setpoint for the Component Cooling System was found to be greater than twice background as listed in Technical Specification 3.7, Table 3.7-5.

Operating in this condition, the Component Cooling System's surge tank vent valve would not have automatically closed at twice background.

This event is contrary to Technical Specification 3.7 (Table 3.7-5) and reportable per Technical Specification 6.6.2.a.

2.

PROBABLE CONSEQUENCE OF EVENT:

The improper alarm setting of the Radiation Monitor for the Component Cooling System had no effect upon the health and safety of the general public.

The unit had recently obtained full power following an extensive 7 months cold shutdown, placing the relative radio-isotope inventory in the Component Cooling System at a small amount.

Therefore, the protection provided by the required response setting for vent isolation was not necessary.

3.

CAUSE OF EVENT

The improper setting of the alarm setpoint for the radiation monitors was due to a failure to recalibrate from full power background following an extensive period of being at cold shutdown.

4.

IMMEDIATE CORRECTIVE ACTION

The immediate corrective action taken was to manually isolate the Component Cooling System's surge tank vent valve and determine a new background radia-tion level.

New alarm and alert setpoints were then set on both monitors.

5.

SCHEDULED CORRECTIVE ACTION:

Periodic Test 26.1, Radiation Monitoring Equipment Daily Check, will be changed to require a verification of alarm and alert setpoints.

6.

ACTION TAKEN TO PREVENT RECURRENCE:

The same as scheduled corrective actions.

7.

GENERIC IMPLICATIONS:

This event possesses no generic implications.