ML20003C722

AO 50-219/74/18:on 740308,w/plant Shutdown,Insp of Drywell Snubbers Located Three Inoperable & Four Leaking.Caused by Loss of Hydraulic Fluid.Units Replaced W/Identical Snubbers Rebuilt W/Ethylene Propylene Seals

ML20003C722
Person / Time
Site:	Oyster Creek
Issue date:	03/18/1974
From:	JERSEY CENTRAL POWER & LIGHT CO.
To:	US ATOMIC ENERGY COMMISSION (AEC)
References
AO-50-219-74-18, NUDOCS 8103160345
Download: ML20003C722 (2)

Text

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OYSTER CREEK NUCLEAR GENERATING STATION FORKED RIVER, NEW JERSEY 08731 Abnormal Occurrence Report No. 50-219/74/18  ; .

Report Date [e y"I -

h ^1 March 18, 1974 (:]' y~;.:' ' ~}, ~l '

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Occurrence Date

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March 8,1974 '

Identification of Occurrence Inoperability of one (1) Bergen-Paterson hydraulic shock and sway arrestor located on the "A" isolation condenser in the drywell. This event is con-sidered to be an abnormal occurrence as defined in the Technical Specifications, paragraph 1.15D.

Conditions Prior to Occurrence The plant was shut down with reactor coolant at <212*F.

Description of Occurrence An inspection of the drywell snubbers, Bergen-Paterson type HSSA-10, located three inoperable units and four which were leaking. 'Ihey are as follows:

Unit System Condition Elev.

F93501 #2 A Isolation Condenser Inoperable 75' 487574 B Isolation Condenser Leaking 95' 487502 B Isolation Condenser Leaking 95' l 487495 Cleanup System Leaking 55' 487573 Shutdown Cooling Inoperable 51'

487489 North Electromatic Relief Leaking 51' 487446 South Electromatic Relief Inoperable 51' l All of the above HSSA units were rebuilt in January 1974 with ethylene propylene seals, except Unit #487489. This unit was rebuilt primarily with molded poly-urethane seals in September 1973.

Of the three inoperable units, only one (F93501 #2) is associated with an engineered safeguard system ("A" Isolation Condenser). It is not believed that temperatures above the normal ambient conditions for the drywell during operation existed in the vicinity of any of the three inoperable units.

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Abnormal Occurrence No. 50-219/74/18 Page 2 Apparent Cause of Occurrence The cause of snubber inoperability was a loss of the hydraulic fluid. An investigation is being initiated to determine why the fluid was expelled.

Analysis of Occurrence The safety significance of this occurrence was a partial loss of the seismic restraining ability for the affected systems. Had the plant suffered a design basis earthquake, the probability that these systems would have suffered

, structural damage was increased.

Corrective Action The seven units were replaced with identical snubbers which were rebuilt with ethylene propylene seals. In addition, pressure tests will be run on the defective units in an attempt to determine the cause of their inoperability and then each of the units will be dismantled to visually determine seal status.

The results of this program will provide additional information toward a res-olution of this problem.

Failure Data Manufacturer: Bergen-Paterson

. Type: ilSSA-10

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