ML19308A988

Abnormal Occurrence AO-269/74-07:on 740425,required Sampling of Condensate Test Tank Not Performed Prior to Release. Caused by Operator Error.Tank Valves More Clearly Identified & Procedure for Liquid Waste Release Modified

ML19308A988
Person / Time
Site:	Oconee
Issue date:	05/06/1974
From:	DUKE POWER CO.
To:
Shared Package
ML19308A984	List: ML19308A983 ML19308A988
References
NUDOCS 7912120749
Download: ML19308A988 (2)

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DUKE POWER COMPANY OCONEE NUCLEAR STATION Report No.: AO-269/74-7 Report Date: May 6, 1974 Occurrence Date: April 25, 1974 Facility: Oconee Unit 1, Seneca, South Carolina Identification of Occurrence: Required sampling of condensate test tank was not performed prior to release Conditions Prior to Occurrence: Oconee Unit 1 was operating at 75 percent full power; Oconee Unit 2 was in cold shutdown Description of Occurrence:

On April 24, 1974, preparations were made to release from A condensate test l

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tank. The tank was sampled as required by Section 3.9.8 and Table 4.1-3 of the Oconee. Technical Specifications; it was determined that the contents i of the tank were well within release limits and that a release rate of 50 gpm was permissible.

1 At 1715, release from the B condensate test tank commenced.

At 1738, a low level alarm from the B condensate test tank was received and the release was stopped.

At 1820, B condensate test tank was sampled. The activity in this tank was well within release limits.

Designation of Apparent Cause of Occurrence:

The apparent cause of this occurrence was operator error in opening the incorrect tank isolation valve. The isolation valves for the two condensate test tanks are in close proximity and identified only by valve numbers.

Analysis of Occurrence:

Liquid releases passed through two radiation monitors, RIA-33 and RIA-34. The dynamic range of these monitors is-designed to cover normal and abnormal:

. releases; one is.used to annunciate a high radiation level, and the other automatically terminates the release. During release from the B condensate test tank, these monitors did not show an increase in count ~ rate, verifying the safe activity level of the water being released. If the effluent had had a high radiation level, the alarm would have alerted the operator to stop:

the release or would have terminated the release automatically.'

9 5912120 l f

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A sample taken from the B condensate test tank indicated that no release limits had been exceeded and the allowable release rate was 50 gpm by the most restrictive factors. Sample results were as follows:

-0 Dissolved Gas 1.56 x 10 pCi/ml

-2 Tritium 3.59 x 10 Ci/ml

-6 Corrosion & Fission Products 3.29 x 10 pCi/ml Gross y 1.16 x 10" pCi/ml Gross 6 1.26 x 10 pCi/ml The occurrence caused no significant impact on the environment and did not affect the health and safety of the public.

Corrective Action:

To prevent recurrence of this or similar incidents, the following corrective action will be taken:

1. The condensate test tank isolation valves will be more cleerly identified to distinguish the A tank from the B tank.

2. The procedure for releasing liquid waste will be modified to require

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verification by the operator making the release that all procedural steps prior to the release have been completed. This verification will be documented on the Liquid Waste Release Form which must be completed prior to any liquid waste release. The shift supervisor will also document that he has reviewed the Liquid Waste Release Form and is satisfied that the release can be properly made.