United States Nuclear Regulatory Commission - Protecting People and the Environment

Bulletin 82-04: Deficiencies in Primary Containment Electrical Penetration Assemblies

                                                 SSINS No.:  6820          
                                                 OMB No.:  3150-0094       
                                                 Expiration Date: 11/30/85 
                                                 IEB 82-04                 

                                UNITED STATES
                           WASHINGTON, D.C. 20555 
                              December 3, 1982

                         PENETRATION ASSEMBLIES 


All nuclear power reactor facilities holding an operating license (OL) or 
construction permit (CP). 


The purpose of this bulletin is to inform CP holders and licensees about 
findings from a joint Region III, Region IV, and IE study concerning 
electrical penetrations supplied by the Bunker Ramo Company.  It was 
concluded that there are potential generic safety implications at a limited 
number of plants.  Therefore, we ask all recipients of this bulletin to 
review the information herein for applicability to their facilities an (1) 
to take appropriate action with respect to deficiencies found if their 
plants utilize hard epoxy containment electrical penetration assemblies 
manufactured by the Bunker Ramo Company or (2) submit reports stating that 
such assemblies are not used in their facilities. 

Description of Circumstances: 

Several deficiencies in containment electrical penetrations supplied by 
Bunker Ramo, have been identified.  A summary of these deficiencies is 
provided below: 

1.   On January 15, 1979, Consumer Power Company submitted 10 CFR 50.55(e) 
     report No. 78-12 for the Midland nuclear facility identifying 
     deficiencies associated with #10 AWG and smaller wire terminations 
     located in the inboard terminal boxes of Bunker Ramo penetration 
     assemblies.  The deficiencies identified included improper lug crimps, 
     incorrect lug types, and loose connecitons on terminal blocks.  These 
     deficiencies were attributed, in part, to an inexperienced employee at 
     bunker Ramo. 

2.   On March 26, 1980, Union Electric Company submitted 10 CFR 50.55(e) 
     report No. 80-03 for the Callaway nuclear facility identifying 
     deficiencies associate,d with electrical penetration assemblies 
     supplied by Bunker Ramo. The deficiencies included improperly crimped 
     lugs and improperly identified penetration cables. During hand-pull 
     tests, at least 38 wires separated from their lugs. It was reported 
     that this deficiency resulted when  Bunker Ramo overcrimped and 
     undercrimped lugs. 


                                                           IEB 82-04       
                                                           December 3, 1982 
                                                           Page 2 of 6     

3.   On June 12, 1980 the NRC was informed by Standardized Nuclear Unit 
     Power Plant Systems (SNUPPS) that additional inspections at the Wolf 
     Creek nuclear facility identified further concerns regarding the 
     quality and integrity of Bunker Ramo electrical penetration 
     terminations. Deficiencies identified at the Wolf Creek facility 
     included improperly crimped lugs and incorrectly sized lugs. 

4.   On October 2, 1980, Commonwealth Edison submitted 10 CFR 50.55(e) 
     report No. 80-02 for the LaSalle County Station Unit 2 facility 
     identifying cracked or missing insulation (exposing bare copper) on 
     small-diameter conductors as they enter/exit the epoxy module portion 
     of the Bunker Ramo electrical penetrations. The report stated, in part, 
     "The cracking was determined to have resulted from stress points in the 
     insulation created by a mechanical bond between the potting compound 
     (used to form the over-mold portion of the module) and the insulation. 
     Movement of the conductors entering or exiting the modules produced 
     cracks along the stress points." 

5.   On March 31, 1982, the NRC was advised through a 10 CFR 21 report that 
     deficiencies have been identified in Bunker Ramo electrical 
     penetrations installed at the Midland nuclear facility. The 
     deficiencies involve #2, #6, #8, #10, #14, and #16 AWG splices and 
     cracks in the insulation of some conductors as they emerge from certain 
     types of modules. The deficiencies were reported to have occurred when 
     site personnel moved cables to inspect for rodent damage. 

6.   On April 8, 1982, Consumers Power Company submitted 10 CFR 50.55(e) 
     report No. 82-02 for the Midland nuclear facility identifying 
     deficiencies in Bunker Ramo electrical penetrations. The identified 
     deficiencies included cracks in conductor insulation at the 
     conductor-module interface (resulting in some exposure of the module 
     copper conductors) and inadequately crimped butt splices (resulting in 
     several #2 AWG butt splices being pulled apart). These deficiencies 
     were observed in installed electrical penetrations. In addition, 
     similar deficiencies were observed in crated electrical penetrations 
     and spare module assemblies stored in warehouse facilities. The cracked 
     insulation was reported to have probably been caused by a 
     chemical/mechanical reaction between the module materials, mechanical 
     stresses resulting from the module design, and a lack of explicit 
     handling/packing instructions reflecting the fragility of electrical 
     penetrations/modules. The inadequately crimped butt splices were 
     reportedly caused by a breakdown in the fabrication/design of the 
     module assemblies. 

The above deficiencies have all been identified on Bunker Ramo electrical 
penetrations utilizing a hard epoxy module design. In addition to the above 
construction sites, Bunker Ramo has identified the Comanche Peak, Byron and 
Braidwood sites as using this design. These deficiencies could result in 
failures of Class 1E equipment essential to the safe operation and shutdown 
of nuclear facilities. The potential failures which could occur include 
electrical short-circuits, localized circuit overheating, adjacent circuit 
cross-talk, and circuit discontinuities. 

                                                           IEB 82-04       
                                                           December 3, 1982 
                                                           Page 3 of 6     

In addition to the above documented deficiencies associated with nuclear 
facilities under construction, a deficiency in Bunker Ramo electrical 
penetrations utilizing a soft epoxy module design has recently been 
identified at Davis-Besse, an operating nuclear facility. Davis-Besse has 
determined that spurious alarms are caused by intermittent voltage drops 
within the electrical penetration module assemblies. To determine the cause 
of the voltage drops, two module assemblies have been removed during the 
current refueling outage and will be shipped to a laboratory for testing. 
Calvert Cliffs, Trojan, and Arkansas plants also use the soft epoxy module 
design. A supplement to this bulletin will be issued, if deemed necessary, 
when the Davis-Besse laboratory results are available. 

Actions to Be Taken by Holders of Operating Licenses or Construction Permits

1.   Plants Under Construction and in Operation 

     If Bunker Ramo electrical penetrations having module assemblies which 
     utilize the hard epoxy module design are not yet installed in safety-
     related systems at your facility (plants), the following actions are 

     a.   Inspect all supplier-provided electrical penetration terminal 
          boxes and verify that the conductor terminations are satisfactory 
          (correct lug sizes, proper crimps, and no loose connections). 

     b.   Inspect all electrical penetration conductors as they enter and 
          exit penetration modules and verify the integrity of the 
          insulation around the conductors. It may be necessary to remove 
          the penetration modules from the assembly to perform this 
          inspection, and removal will be necessary to conduct the 
          examination discussed in Item c below. 

     c.   Conduct detailed examinations of all supplier-provided in-line 
          butt splices having a wire size of #2 AWG and smaller, and 
          ascertain acceptability of these connections. 

2.   Plants Under Construction 

     If Bunker Ramo electrical penetration assemblies utilizing the hard 
     epoxy module design are installed in safety-related systems at your 
     facility, the following actions are requested: 

     a.   Inspect the accessible* portions of all installed assemblies as 
          described in Items 1a and 1b above. 

*Throughout this bulletin the accessible portions are considered to be all 
 of the supplier-provided electrical terminations (see Item 1a) and those 
 parts of the penetration modules (Item 1b) that can be inspected while the 
 assemblies are in place. 

                                                           IEB 82-04       
                                                           December 3, 1982 
                                                           Page 4 of 6     

     b.   Remove a sample of penetration modules from the assemblies and 
          inspect the sample as described in Item 1b and 1c above.  Minimum 
          sample size considered acceptable shall be the greater of two 
          modules or 10% of the modules for each wire size. 

          If failures are identified in either the non-installed assemblies 
          (Items 1b and 1c) or in the sample from the installed assemblies, 
          the sample size shall be appropriately increased. 

3.   Plants in Operation: 

     If Bunker Ramo electrical penetraion assemplies utilizing the hard 
     epoxy module design are installed in safety-related systems at your 
     facility, you are requested to review past operational and related 
     maintenance records of these electrical penetration units for circuit 
     fuctionability problems similar to those discussed in this bulletin.  
     If such problems have occurred, or if the inspection of spare 
     assemblies in accordance with Item 1 have identified deficiencies, then 
     the following actions are requested: 

     a.   Provide a basis for continued plant operation if problems as 
          discussed in this bulletin are identified. 

     b.   Develop a plan for inspection of the installed assemblies.  This 
          plan should address the types of problems identified by past 
          operational history and/or the inspection of non-installed spares. 
          The plan should identify the wire sizes to be examined. 

          (1)  If problems were only identified in accessible portions of 
               the assembly then the sample may be restricted to that 

          (2)  If problems included inaccessible portions, then the sample 
               shall include inaccessible portions of the assembly.  This 
               will require removal of the module from the assembly. 

4.   Repairs to conductor terminations, module insulation and butt splices 
     identified as unacceptable under provisions of Items 1, 2 or 3 above 
     shall be performed in accordance with appropriate procedures. 

     Initiate replacement or repair of any supplier-porvided conductor 
     termination, module insulation, or in-line butt splice if they are 
     determined to be unacceptable based on the inspections ond examinations
     discussed in Items 1 through 3 above.  If the repairs involve 
     recrimping of connections(s), such actions must be supported by 
     documentation containing the results of the qualification tests 
     conducted to support these corrective actions.  This is to include pull 
     tests on similarly installed sample connections from your facility.  An 
     acceptable alternative would be type 

                                                         IEB 82-04         
                                                         December 3, 1982  
                                                         Page 5 of 6       

     tests of recrimped connections of each wire size, performed by the 
     connector manufacturer. These sample connections must be of similar 
     parameters (i.e., wire size, connector type, qualified crimping tool 
     and crimping procedures, etc.) as those of the connectors in question. 
     Replacement of suspect connections with other types of connectors must 
     also be supported by similar qualification documentation. 

5.   Complete the actions specified by this bulletin and provide a written 
     report within 90 days of the date of this bulletin that either: 

     a.   States that no Bunker Ramo electrical penetration which use the 
          hard epoxy module design are installed or planned to be installed 
          in safety related systems at your facility. (No further action is 
          needed), or 

     b.   (1)  Provides the results of those actions discussed in Items 1a, 
               1b, 1c, and 4 above, as they apply to penetration assemblies 
               identified as either spare units or units not yet installed. 

          (2)  Provides the results of those actions discussed in Items 2 
               and 4 above, as they apply to plants under construction. The 
               report must be submitted prior to issuance of an OL, if such 
               action is contemplated within the 90 day period following the
               date of issuance of this bulletin. 

          (3)  Provides the results of those actions discussed in Items 3a, 
               3b, and 4 above, as they apply to operating plants, including
               your plan and schedule for completing the required 
               inspections, and also provides your basis for continued 

6.   Provide a report describing the results of the inspections discussed in
     Item 3b and addressed by the plan described in the report specified in 
     5b(3) above, within 60 days of completion of the inspections. 

The written reports required by Items 5a, 5b(1), 5b(2), 5b(3), and 6 above 
shall be submitted to the appropriate Regional Administrator under oath or 
affirmation under provisions of Section 182a, Atomic Energy Act of 1954 as 
amended. The original copy of the cover letters and a copy of the reports 
shall be transmitted to the U.S. Nuclear Regulatory Commission, Document 
Control Desk, Washington, D.C. 20555 for reproduction and distribution. 

This request for information was approved by the Office of Management and 
Budget under clearance number 3150-0094 which expires on November 30, 1985. 
Comments on burden and duplication should be direcied to the Office of 
Management and Budget, Reports Management, Room 3208, New Executive Office 
Building, Washington, D.C. 20503. 

                                                          IEB 82-04        
                                                          December 3, 1982 
                                                          Page 6 of 6      

While no specific request or requirement is intended, the following informa-
tion would be helpful to the NRC in evaluating the cost of implementing this

1.   Utility staff time to perform requested inspection. 
2.   Radiation exposure attributed to requested inspections. 
3.   Utility staff time spent to prepare written responses. 

If you have any questions regarding this matter, please contact the Regional
Administrator of the appropriate NRC Regional Office, or the technical con-
tact listed below. 

                                   Richard C. DeYoung, Director 
                                   Office of Inspection and Enforcement 

Technical Contact:  V. D. Thomas 

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