ML20087L018

RO 76-5:on 750311,pressure Switch Setting for Recirculation Actuation Signal Had Drifted Upward in Excess of Tech Spec Limit.Design Change Request Initiated on 750313 to Develop Mod to Existing Design to Ensure Conformance

ML20087L018
Person / Time
Site:	Fort Calhoun
Issue date:	07/16/1976
From:	Short T OMAHA PUBLIC POWER DISTRICT
To:	Howard E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML20087K990	List: 05000285/LER-1976-005, Suppl 1 to LER 76-05/03L:on 770210,recirculation Actuation Pressure Switches Found Out of Tolerance.Cause Not Stated. Switch Will Be Calibr Monthly Until New Switches Installed ML20087L018
References
RO-76-5, NUDOCS 8403260403
Download: ML20087L018 (2)

Text

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1923 HARNEY a OMANA. NESRASMA 68102 e TELEPHONE S30 4000 AREA CODE 402 July 16, 1976 FC-22h-76 9_ ,[*It 7 l &l Mr. E. Morris Howard U. S. Nuclear Regulatory Commission A g [V #876 [

Region IV 611 Ryan Plaza Drive e

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Dear Mr. Howard:

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Subject:

Recirculation Actuation Signal Setpoint Drift

References:

(1) Abnormal Occurrence Report 50-285/75-5 dated March 14, 1975 (2) Licensee Event Report 50-28p/76-5 dated March 19, 1976 This letter is intended to provide your office with the current status of our progress in resolving the Recirculation Actuation Signal Setpoint Drift as previously reported in References (1) and (2).

During the calibration of the Safety Injection and Refueling Water Tank level channels on March 11, 1975, it was observed that the pressure switch settings for the Recirculation Actuation Signal had drifted upward in excess of the allowed Technical Specification limit as specified in Table 2-1, Item .

5 The allovable Technical Specification limit is 16(+0, -2) inches of water.

These limits ensure that 283,000 gallons of water at the refueling boron con-centration are available for the accident as well as preventing the loss of suction to the safety injection pumps.

The installed Barkendale D2tM-80P2 pressure switches have a range of 0-18 psig, with a setpoint repeatability of 114 (14 98 inches of water). A design change request vac initiated on March 13, 1975, in order to develop a modification to the existing design which would ensure conformance with the Technical Specification limits.

The P.Lant Review Committee recommended that the pressure switch setpoint for the Recirculation Actuation Signal be changed to 1914 98. inches and that the Safety Injection and Refueling Water Tank high and low level alarm set- ,

points be increased to ensure that a minimtun of 283,000 gallons of water at the refueling boron concentration would be available. The Technical Services' section concurred with this recommendation.

7362

-m cofr? smr REGION 8403260403 771031 PDR ADOCK 05000285 q S PDR

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j I4't . E. Morrio llovard O .

July 16,1976 Page Two Continued netpoint drift problems have necessitated that the Barkes-dale precoure nvitches be removed and replaced with preccure switchen which vill provide the required accuracy. The calibration frequency of the Barken-dale pressure switchec han been increased to a monthly calibration in order to minimize drift effects. These monthly calibrations have determined that the cetpoint had drifted but the present setpoint plus drift experience has ensured that more than 283,000 gallons of water are available. The design change request in undergoing final design. New pressure switches will be (

installed as soon an the design is completed and the parts are available. i Sincerely, (7 1 r

'T T.[, E.' uShort c(

Division Manager Production Operations TES/WDD/SCS:amh

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