United States Nuclear Regulatory Commission - Protecting People and the Environment

Bulletin 73-04: Defective Bergen-Patterson Hydraulic Shock Absorbers Information

                                                             IEB 73-04

                                 UNITED STATES
                           ATOMIC ENERGY COMMISSION
                             REGION II - SUITE 818
                        230 PEACHTREE STREET, NORTHWEST
                            ATLANTA, GEORGIA 30303

                                        August 17, 1973


The reports of your action in response to Regulatory Operations Bulletin
No. 73-3, dated July 27, 1973, and other information concerning Bergen-
Patterson hydraulic shock absorbers, indicate that additional action is

Enclosed is Regulatory Operations Bulletin No. 73-4 which provides you with
additional information and lists certain actions that appear appropriate on a
timely basis.  The Directorate of Licensing currently is evaluating the need
for a continuing surveillance program for hydraulic shock absorbers.

You are requested to take the action shown under ACTION INDICATED in the
enclosed Regulatory Operations Bulletin No. 73-4, dated August 17, 1973.

Should you have any questions concerning this matter, please contact me.


                                            Norman C. Moseley

Regulatory Operations Bulletin
  No. 73-4, Dated August 17, 1973


                                                 Regulatory Operations
                                                   Bulletin No. 73-4
                                                 Date:  August 17, 1973



Reference is made to Regulatory Operations Bulletin 73-3, dated July 27, 1973,


information on known problems with hydraulic shock absorbers and which 

requested actions, including inspections of installed hydraulic shock 

absorbers, by certain utilities.

The compiled results of these inspections of Bergen-Patterson shock absorbers,

based on telephone reports from affected licensees to the five Regional 

Offices of the Directorate of Regulatory Operations, reveal that a large 

percentage of installed Bergen-Patterson hydraulic shock absorbers were not 

fully operational.  In addition, preliminary information indicates that 

routine repairs, replacing defective seals and filling hydraulic oil 

reservoirs, may not be an adequate long-range solution to this problem.  There

is also some indication that deterioration of the affected hydraulic shock 

absorbers can occur over a relatively short period of time (less than 90 



1.  Schedule and conduct a reinspection of Bergen-Patterson hydraulic shock 

absorbers installed in safety related systems following approximately 45 days 
and no longer than 90 days after the plant has been at operating temperature 

subsequent to the inspection performed as requested in RO Bulletin 73-3.


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2.  The inspection should include:

a.  Determination of condition of seals.

b.  Verification of overall integrity of shock absorber assemblies.

c.  Examination for loss of fluid, fluid leaks, and other signs of distress.

d.  Recording of piston rod extension and fluid level indicator positions.

3.  Inform this office of the planned date for reinspection of the 

Bergen-Patterson hydraulic shock absorbers.

4.  Provide this office with a prompt telephone report of the significant 

findings of this reinspection.  If defective shocks are identified, a written 
report should be submitted to this office within 10 days following completion 
of the inspection; if no defective shock absorbers are identified, the written

report should be submitted within 30 days following the completion of the 


5.  The written report should include:

a.  As appropriate, a description of the mode of failure, corrective action 

and tests performed to determine the adequacy of the repair.

b.  A description of the program for the development and subsequent 

installation of a permanent modification to the hydraulic shock absorber 

installation to assure proper operation.  The description should include the 

technical basis for the conclusion that deficiencies in the Bergen-Patterson 

hydraulic shock absorbers have been resolved.

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