Information Notice 1979-01, Bergen-Paterson Hydraulic Shock & Sway Arrestors (Hssa)

Bergen-Paterson Hydraulic Shock & Sway Arrestors (Hssa)

ML031180105
Person / Time
Site:	Browns Ferry, 05000000
Issue date:	02/02/1979
From:	NRC/IE
To:
References
IN-79-001, NUDOCS 7902120059
Download: ML031180105 (3)

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF INSPECTION AND ENFORCEMENT

WASHINGTON, D. C. 20555 February 2, 1979 IE Information Notice No. 79-01 BERGEN-PATERSON HYDRAULIC SHOCK AND SWAY ARRESTORS

(HSSA)

On December 4, 1978, Rancho Seco Nuclear Generating

the failure of seven Bergen-Paterson HSSA (Snubber) Station reported

the compression direction and the failure of one units to lockup in

additional unit to

lockup in the extension direction. These failures

during surveillance testing and the affected models were identified

HSSA-10-6 and HSSA-20-6. When the units were included HSSA- 3-6 observed damage to the poppet valve and seat on disassembled, the licensee

the compression side

of the valve blocks of the seven units that failed

direction. It was also observed that five of in the compression

the seven units had the

poppet spring entrapped between the poppet and

attributed the seven failures in the compressionthe seat. The licensee

direction to abusive

handling during compression of the units for installation

testing at the previous refueling outage. The following

failure in the extension direction has not been cause of the single

determined. In addition

to exercising greater care in reinstallation, functionally test all Bergen-Paterson snubbers the licensee committed to

subjected to transient

conditions which cause either physical damage to

of piping. This testing will include verificationor significant movement

lockup and bleed. The Bergen-Paterson Technical of piston movement, recommends that additional inspections should Maintenance Manual

be

may have participated in an unusual shock occurrencemade on units which

to piping or equipment. involving known damage

On January 3, 1979, the licensee reported that

the decay heat removal

system had been subjected to a transient condition

"water hammer." This transient, caused pipe movement in the form of a

damage two rigid pipe support wall attachments. great enough to

The

testing of the affected Bergen-Paterson units revealed subsequent functional

units failed the lockup test. This unit (Model that one of seven

disassembled and damage to the poppet valve and No. HSSA-3-6) was

seat was observed.

The damage to the poppet valves is presently being

the licensee and Bergen-Paterson. At this time, reviewed by both

not been completely defined nor has appropriate the cause of damage has

determined. Other licensees have reported instancescorrective action been

damage; however, the cause and extent of damage of poppet valve

are not known at

this time.

7 904Zffi#

IE Information Notice No. 79-01 February 2, 1979 This information is provided as an early notification of a possibly

significant matter. It is expected that recipients will review the

information for possible applicability to their facilities. No specific

action or response is requested at this time. If further NRC evaluations

so indicate, an IE Circular or Bulletin-will be issued to recommend or

request specific licensee actions. If you have questions regarding

this matter, please contact the Director of the appropriate NRC Regional

Office. II

IE Information Notice No. 79-01 February 2, 1979 LISTING OF IE INFORMATION NOTICES

ISSUED IN 1979 Information Subject Date Issued To

Notice No. Issued

An Information Notice is a new method of communicating items of

potential interest to licensees. This item, Information Notice

No. 79-01, is the first of this new form of communication.