ML20084E195

AO 50-244/74-10:on 740613,valve 991,outlet from Primary Sys Flow Indicator FI-903 to Channel Drain Tank Reported Open. Caused by Improperly Verified Valve Alignment.Valve 991 Locked Closed

ML20084E195
Person / Time
Site:	Ginna
Issue date:	06/21/1974
From:	Amish K ROCHESTER GAS & ELECTRIC CORP.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20084E197	List: ML20084E195 ML20084E199
References
AO-50-244-74-10, NUDOCS 8304140423
Download: ML20084E195 (3)

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ROCHESTER GAS AND ELECTRIC CORI'ORATIOH e 89 EAST AVENUE, ROCHESTER, N.Y.14649

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Mr. James P. O'Reilly, Director Directorate of Regulatory Operations

"y, ,c O Region I $*4'q' U. S. Atomic Energy Commission 631 Park Avenue King of Prussia, Pennsylvania 19406

Subject:

Abnormal Occurrence 74-10: An unplanned releaee of a2dioncriva maranal fm- te rite beundarf R. E. Ginna Nuclear Power Plant, Unit No.1 Docket No. 50-244

Dear Mr. O'Reilly:

In accordance with Technical Specifications, Article 6.6.2a, the attached report of Abnormal Occurrence 74-10 is hereby submitted.

Very truly yours ,

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9 Keith W. Amish Attachment f

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1. Report Number: 50-244/74-10 2a. Report Date: June 21,1974 2b. Occurrence Date: June 13,1974

3. Facility:

R. E. Ginna Nuclear Power Plant, Unit No.1

4. Identification of Occurrence: '

This abnormal occurrence is defined by Technical Specifications 1.9c:

An unplanned release of radioactive gas from the site boundary.

5. Conditions Prior to Occurrence:

The plant was operating at a steady-state power level of 70%. Primary sample system flow indicator FI-903 maintenance had been performed.

6. Description of Occurrence:

At 1535 hours0.0178 days <br />0.426 hours <br />0.00254 weeks <br />5.840675e-4 months <br /> on June 13, 1974, after completion of the above mainten-ance, the flow indicator was restored to service. Shortly after this, the sample system was restored to service to allow continuous flow to a Westinghouse experimental on-line reactor coolant activity monitor.

At 1715 hours0.0198 days <br />0.476 hours <br />0.00284 weeks <br />6.525575e-4 months <br />, when an automatic makeup to the primary system occurred, it was noted that an increase in the leak rate was indicated and an invectigenen was started luimediately. At 1717 nmrc. a ecmputer 01:rm from the Auxiliary Building ventilation gas monitor sounded. This alarm indicated an increase from about 120 counts per minute to 200 counts per minute, equivalent to 0.3% of the Technical Specifications limit.

At approximately 1750 hours0.0203 days <br />0.486 hours <br />0.00289 weeks <br />6.65875e-4 months <br />, the primary auxiliary operator reported the '

chemical drain tank level was indicating at or about 100%. Simultaneously, the Health Physics Technican reported that valve 991, an alternate outlet from FI-903 to the chemical drain tank, was open. This is a normally 4

' closed valve. The valve, No. 991, was immediately closed and the i

chemical drain tank level was restored to a normal level.

i 4 By approximately 1900 hours0.022 days <br />0.528 hours <br />0.00314 weeks <br />7.2295e-4 months <br />, the Auxillary Building ventilation gas monitor i

reading had returned to the level observed prior to the incident.

i 7. Designation of Aeparent Cause of Occurrence:

i Reactor coolant was allowed to flow to the chemical drain tank. Associated dissolved radiogases were released and drawn through the tank vent into the Auxiliary Building ventilation system.

When the flow indicator FI-903 and the sample system were restored to j service, the valve alignment was not properly verified as described in Sample System Procedure S-5. ,

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Furthermore, during the operator's investigation, it was noted that the high level alarm for the chemical drain tank was not operating properly.

Subsequent investigation by instrument and control personnel revealed that the alarm card was improperly inserted.

8. Analysis of Occurrence:

The release did not cause any hazard to plant personnel or the public. '

The exhaust of the Auxiliary Building ventilation system includes charcoal filters and HEPA filters which remove lodine and particulate activity before the air is released through the plant vent to the atmosphere.

The plant vent is continuously monitored for radioactive gases, particulate and lodine.

There was no increase in iodine or long-lived particulate activity measured by the plant vent monitors. Prior to the incident, the Auxiliary Building gas monitor was indicating a release rate of approximately 0.08% of the Technical Specifications limit. During the two hours of the incident 0.9 curies of noble gases were released from the Auxiliary Building exhaust, amounting to 0.3% of the Technical Specifications limit.

9. Corrective Action:

Valve 991, which is normally closed, will be locked closed. In the future, all maintenance on the primary sample system is to be guided by an approved procedure.

The alarm card for the chemical drain tank was properly installed during the investigation by instrument and control personnel. In addition to this, a system was commenced to ensure that the alarms are tested each day for proper operation.

10. Failure Data:

Not applicable. -

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