ML20064H434

/03L-0 on 781114:4 of 6 High Pwr Rod W/Drawal Prohibit Trip Points Were Set Too High.Accepted Test Procedure Voltage Range Permitted RWP to Be Set Higher than Tech Specs Allow

ML20064H434
Person / Time
Site:	Fort Saint Vrain
Issue date:	12/14/1978
From:	Gahm J PUBLIC SERVICE CO. OF COLORADO
To:
Shared Package
ML20064H431	List: ML20064H430 ML20064H434
References
LER-78-035-03L, LER-78-35-3L, NUDOCS 7812200210
Download: ML20064H434 (4)

Text

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EVENT DATE 74 75 REPORT DATE 80 EVENT DESCRIPTION AND PRG8ABLE CONSEQUENCES h I o l a j l Af ter performance of a surveillance test. four of six high power Rod Withdrawal Pro- I l o l a I l hibit (RWP) trip points were left at a setting slightly greater than 30%. Table I l o I .31 14.4-4 of LCO 4.4.1 specifies a setting of less than or equal to 30%. Therefore, this l,-

I o i s l I condition is reportable per Fort St. Vrain Technical Specification AC 7.5.2(b)1. l.

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I i i O I IProcedure was defective because che accenenkle vntenta vnn te ni l mtra d in Pha li ii l l procedure permitted RWP to be set too high. Surveillance test was revised and I

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. REPORT DATE: December 14. 1978 REPORTABLE OCCURRENCE 78.-35 ISSUE O OCCURRENCE DATE: Novemb er 14, 1978 Page 1 of 3 4

FORT ST. VRAIN NUCLEAR GENERATING STATION PUBLIC SERVICE COMPANY OF COLORADO P. O. BCi 361 PLATTEVILLE, COLORADO 80651 REPORT No. 50-267/ 78-35/03-t-0 Final '

IDENTIFICATION OF OCCURRENCE:

Af ter performance of a routine surveillance test, four of six Linear Channel-High Power Rod Withdrawal Prohibit (RWP) trip points were left at a setting I

greater than 30%. Table 4.4-4 of LCO 4.4.1 specifies an RWP trip point setting of less than or equal to 30%. Therefore, this condition is reportable per Fort St. Vrain Technical Specification AC 7.5.2(b)l.

EVENT DESCRIPTION:

On July 20, 1978, a routine surveillance test of the Linear Power Range Chan-nel Calibration was performed. This surveillance test specified a high power RWP trip point voltage of 2.0 volts with a voltage tolerance of 0.05 volts.

The 2.0 volt trip point corresponds to a reactor power of 30%. Therefore, when the + 0.05 volt tolerance was utilized, a trip point in excess of 30%

reactor power was possible.

l The "as left" conditions for,the surveillance test were as follows:

Channel ,

" As Le f t" Volts Equivalent Power

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3 2.01 30.2%

i 4 2.02 30.3%

l l 5 2.02 30.3%

6 2.02 30.3%

7 1.99 29.8%

8 2.00 30.0%

i The settings of Channels 3, 4, 5, and 6 were less conservative than those i

established by the Technical Specifications, but did not prevent the fulfill-ment of their functional requirements.

The discrepancy between the surveillance test and the Technical Specification setpoints was discovered during a routine audit performed by plant Quality

Assurance personnel.

1

REPORTABLE OCCURRENCE 78-35 ISSUE O Page 2 of 3 CAUSE l DESCRIPTION:

The procedure was defective because the acceptance voltage range stated in the surveillance test allowed four RWP trip points to be left at a setting greater than 30%. The voltage tolerance of 10.05 volts was specified because it is within the_a_ccura.:y capability of the test instrumentation.

CORRECTIVE ._.

ACTION:

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~~~~ The is~uMiilance test setpoints have been revised to a voltage range of 1.93

__1_0.06 volts,_which corresponds to a reactor power of 29 i 1%. The nuclear instrumentation has been readjusted using this revised criteria.

(m. No further corrective action is anticipated or required.

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• . REPORTABLE OCCURRENCE 78-35 ISSUE O Page 3 of 3 Prepared by: ( 0 ./4 /

Charles H. Fuller Technical Services Technician '

Reviewed by: /[ /

. W Mm echnical Services Supervisor O

Reviewed by.

Frank M. Mathie Operations Manager Approved by: ,

Mtv.d u Don Warembourg f[

Manager, Nuclear Proddttion O