ML19345G170

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AO 74-04:on 740301,dry Boric Acid Deposits Found on External Surfaces of Containment Air Charcoal Filters.Caused by Charcoal Filter Spray Valve Leakage.Extent of Acid Contamination & Cause of Leakage Under Investigation
ML19345G170
Person / Time
Site: Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png
Issue date: 03/04/1974
From: Hartley F
CONNECTICUT YANKEE ATOMIC POWER CO.
To: James O'Reilly
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
AO-74-04, AO-74-4, CYH-2609, NUDOCS 8103100161
Download: ML19345G170 (2)


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Dear Mr. O'Reilly,

As defined by Technical Specifications, for Connecticut Yankee Atomic Power .tation Section 5.3, the following information involving possible degr.idation of one of four containment air charcoal filters is reported a. Abnormal Occurrence 74-4.

The Connecticut Yankee reactor containment atmospheric control system includi s a filtration system for removing radioactive fission products from the contairment atmosphere following an incident which releases fission products from the core. The filtration system utilizes the air recirculation fans as a driving force. The filters are located in four separ.ite banks connected to the inlet plenums of the four air recirculation fans. The filter banks consist of moisture seoarators,

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absolute type filters and activated charcoal filters; additionally a fire protection spray system is installed within the filter enclosure which is supplied from the Residual Heat Removal System.

During the routine weekly reactor containment inspection conducted on March 1,1974 dry boric acid was observed on the floor adjacent to the #4 air recirculation fan unit.

Further inspection within the filtration unit revealed boric acid deposits on the external surfaces of several of the charcoal filter units.

It appears that borated water from the charcoal filter spray system leaked past the charcoal filter spray valves and deposited on several of the charcoal filter units.

An investigation is currently being conducted to evaluate the extent of boric acid contanination and the need for replacement or testing of individual filter units.

The containment air recirculation / filtration system is designed to perform its function with only three of the four operable. The other three units were inspected and found to be free of boric acid contamination.

A follow-up report will be submitted within ten days.

P90R ORIGINAL Very truly yours, 7103 /00M /

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