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
NUCLEAR REGULATORY COMMISSION
OFFICE OF INSPECTION AND ENFORCEMENT
WASHINGTON, D.C. 20555
December 3, 1982
IE BULLETIN NO. 82-04: DEFICIENCIES IN PRIMARY CONTAINMENT ELECTRICAL
PENETRATION ASSEMBLIES
Addressees:
All nuclear power reactor facilities holding an operating license (OL) or
construction permit (CP).
Purpose:
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.
8208190259
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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.
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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
requested:
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.
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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
portion.
(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
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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
operation.
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.
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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
bulletin:
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
301-492-4755
Attachment:
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