ML19282A868

RO NP-09-79-04:on 790126,station Vent Monitor Re 2024 Generated Excessive Noise;Later Pump for Station Vent Monitor Re 2025 Seized.Caused by Normal Vane Wear & Low Flow During Testing.Pumps for Both Monitors Replaced

ML19282A868
Person / Time
Site:	Davis Besse
Issue date:	02/21/1979
From:	TOLEDO EDISON CO.
To:
Shared Package
ML19282A867	List: ML19282A866 ML19282A868
References
NUDOCS 7903070226
Download: ML19282A868 (2)

Text

TOLEDO EDISON COMPANY DAVIS-BESSE NUCLEAR POWER STATION UNIT ONE REPORTABLE OCCURRENCE NP-09-79-04 DATE OF EVENT: January 26, 1979 FACILITY: Davis-Besse Unit 1 IDENTIFICATION OF OCCURRENCE: Station Vent Monitors RE 2024 and RE 2025 declared inoperable.

Conditions Prior to Occurrence: The unit was in Mode 4, with Power (MWT) = 0, and Load (Gross MWE) = 0.

Description of Occurrence: On January 22, 1979, station vent monitor RE 2024 was observed to be generating excessive noise. The monitor was secured and declared inoperable. On January 26, 1979, during the performance of Surveillance Test ST 5032.01, "Manthly Functional Test of the Radiation Monitor System", the pump for the station vent monitor RE 2025 seized. At 1440 hours0.0167 days <br />0.4 hours <br />0.00238 weeks <br />5.4792e-4 months <br />, RE 2025 was declared inoperable.

This was not in accordance with Environmental Technical Specification 2.4.4, which requires a minimum of one monitor to continuously monitor the station vent. Devia-tion from this requirement requires daily grab samples until the monitors are returned to service, up to seven days,at which time all releases must terminate.

Station vent monitor RE 2024 was repaired and operationally tested. On January 26, 1979 at 1720 hours0.0199 days <br />0.478 hours <br />0.00284 weeks <br />6.5446e-4 months <br />, RE 2024 was declared operational. Due to the short duration that there was no continuous sampling (less than three hours), no grab samples were taken.

Designation of Apparent Cause of Occurrence: The failure of RE 2024 was attributed to normal vane wear. The subsequent failure of RE 2025 is believed to be a result of excessively low flow conditions during testing.

Analysis of Occurrence: There was no danger to the health and safety of the public or to unit personnel. No gaseous releases were made during the time that the sta-tion vent monitors were not available.

Corrective Action: Under Maintenance Work Order 79-1323, the excessive noise of RE 2024 was investigated. On January 26, 1979, the failing pump was replaced and operationally tested. The seized pump of RE 2025 was replaced under Maintenance Work Order 79-1389. The pump was replaced and operationally tested. On January 28, 1979, at 0730 hours0.00845 days <br />0.203 hours <br />0.00121 weeks <br />2.77765e-4 months <br />, RE 2025 was declared operational. Normal wear life has been established and the preventative maintenance program has been adjusted accordingly.

7008070 A2[o ,

TOLEDO EDISON COMPANY DAVIS-BESSE NUCLEAR POWER STATION UNIT ONE REPORTABLE OCCURRENCE NP-09-79-04 PAGE 2 Failure Data: Similar occurrences of radiation monitor failures were previously reported in Licensee Event Reports ':?-33-78-30, NP-33-78-143 and NP-33-78-77.

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