ML20054F767
| ML20054F767 | |
| Person / Time | |
|---|---|
| Site: | Midland |
| Issue date: | 06/09/1982 |
| From: | Jackie Cook CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, 17514, 82-02-#3, 82-2-#3, 82-2-3, MCAC-56, MCAR-56, NUDOCS 8206170304 | |
| Download: ML20054F767 (6) | |
Text
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Consumers Power Jernes W Cook 0f Vice President - Projects, Engineering and Construction General Offices: 1945 West Parnell Road. Jackson, MI 49201 * (517) 788 045:'
82-02 #3 June 9, 1982 Mr J G Keppler, Regional Administrator US Nuclear Regulatory Commission Region III 799 Roosevelt Road Glen Ellyn, IL 60137 MIDLAND PROJECT -
DOCKET NOS 50-329 AND 50-330 ROTENT DAMAGE TO ELECTRICAL PENETRATION W131HG AND CABLES FILE:
0.h.9 58 SERIAL: 1751h
References:
J W Cook letters to J G Keppler, Same
Subject:
- 1) Serial 16107, dated February 19, 1982
- 2) Serial 16160, dated April 8, 1982 The referenced letters were interim 50 55(e) reports concerning rodent damage to electrical penetration viring and cables. This letter is the final report on this subject. The attachment to this letter provides a final status of the course and schedule of corrective action to be taken to resolve this issue.
hTB/lr l
Attachment:
MCAR 56, Final Report, " Damage to Electrical Penetration l
Assemblies," dated May 26, 1982 CC:
RJCook, NRC Resident Inspector Midland Nuclear Plant l
Document Control Desk, NRC Washingt on, DC l
l t
M 1 g h-8206170304 820609 PDR ADOCK 05000329 PDR S
. lLlf.
Scrial IT51h 82-02 #3 2
CC:
CBechhoefer, ASLB Panel RSDecker, ASLB Panel FPCowan, ASLB Panel JHarbour, ASLB Panel AS&L Appeal Panel MMCherry, Esq MSinclair BStamiris CRStephens, USNRC WDPaton, Esq, USNRC FJKelley, Esq, Attorney General SHFreeman, Esq, Asst Attorney General WHMarshall GJMerritt, Esq, TNK&J l
t
071357 Attachment to 07I47i seria1 ma 82-02 #3
SUBJECT:
MCAR 56 (Revised)
Damage to Electrical Penetration Assemblies FINAL REPORT DATE:
May 26, 1982 PROJECT:
Consumers Power Company Midland Plant Units 1 and 2 Bechtel J0b 7220
REFERENCES:
A) CPCo letter Serial CSC-5830,12/3/81 B) CPCo NCR M01-9-1-165, 12/28/81 C) SCRE 39, 1/15/82 Introduction This report provides the final status and course of corrective action required pursuant to MCAR 56, revised March 1, 1982. In addition to the deficiency covered by the original issue of this MCAR, several other deficiencies have been noted during the ongoing inspection of the Class 1E assemblies.
Description of Deficiencies 1.
During post-construction surveillance inspection of the Class 1E electrical panetration assemblies (EPAs), assembly 2Z135 revealed rodent damage to the outboard side module wiring. The damage consisted of chewed insulation resulting in exposed and/or severed conductors.
Subsequent inspection of additional Class 1E assem-blies reveab f similar damage.
2.
Conductor insulation cracking at the conductor-module interf ace resulted in some exposure of the module conductors.
3.
Inadequately crimped in-line butt splices occurred, which could result in discontinuity or potential localized overheating in circuits terminated in the EPAs.
4.
A crack in the sealing surface of a module, resulting in a pressure leak which degraded the EPAs ability to provide a constant pressure boundary.
(Note: Leaking modules / header plates are noted during routine inspection and are repaired as required.)
071357 07I47I MCAR 56 Final Report Page 2 Corrective Action A.
Construction has initiated a reemphasis on rodent control including:
1.
Removal of all nesting and debris from the EPA sleeves and surrounding areas 2.
Additional rodent baiting with revised location of the bait 3.
An increase in the frequency of surveillance by the rodent control subcontractor 4.
A program of rodent control consisting of disseminating rodent control information to all craf t onsite through tool box safety meetings, education of personnel on the identification and signi-ficance of the types of bait and traps being used, the importance of not moving or altering them, and the need to report evidence, sightings, or dead animals to the appropriate individuals 5.
Instructing construction to seal all EPAs to prevent the reentry of rodents (Note:
All corrective action in A above have been completed)
B.
Construction has completed its inspection of all EPAs used for Class 1E circuits to determine the extent of rodent damage. With the decision to replace all #2 AWG through #20 AWG modules the need to inspect for other deficiencies is not required.
C.
Engineering has identified a generic deficiency (Deficiency 2) in
- 2 AWG through #20 AWG penetration modules.
i 1.
Engineering has procured qualified replacement modules for all EPAs (#2 AWG through #20 AWG), to correct deficiencies 2 and 3.
2.
Engineering has obtained and accepted repair / replacement proce-dures from the EPA manufacturer (2/0 AWG through 350 MCM and coaxial type modules), for deficiency 1.
3.
Construction is repairing rodent damaged module wires (2/0 AWG through 350 MCM and coaxial type modules) in accordance with the accepted procedures.
4.
The cracked module (Module G of EPA 12110) will be replaced.
5.
Construction is replacing all modules, #2 AWG through #20 AWG, with qualified replacement modules.
,n.
n, - -,
071357 07l47i MCAR 56 Final Report Page 3 D.
Root Causes 1.
The deficiency is a result of rodents entering / nesting in the EPAs and chewing on module wiring. Access into the EPAs' was via the cable feedthrough nipples.
2.
The root cause of the insulation cracking has not been positively identified to date. It is our belief that the cause of the insulation cracking is overaging of the insulation during the module molding process. It is believed that the curing of epoxy molding material resulted in an internal temperature which degraded the insulation and provided the foundation for insulation cracking. The exact materials used in the molding process are considered by the module manufacturer (Bunker Ramo) to be proprietary in nature and therefore the exact effect on the insulation materials cannot be readily deter-mined.
3.
The root cause of the inadequately crimped butt splice has been determined to be a breakdown in the fabrication / design of the module assemblies.
4.
The crack is considered an isolated case; therefore, no evalua-tion for a root cause was performed.
Safety Implications 1.
The rodent damage consisted of chewed insulation resulting in exposed and/or severed conductors. Exposed conductors could result in circuit shorts and severed conductors could result in circuit discontinuities; therefore, equipment necessary to safely operate the plant may have failed.
2.
The cracked insulation resulted in some exposure of the module conductors. Exposed conductors could result in circuit shorts; therefore, equipment necessary to safely operate the plant may have failed.
3.
The inadequately crimped butt splice could result in circuit dis-continuities or potential localized overheating. Therefore, equipment necessary to safely operate the plant may have failed.
4.
There is no generic safety implication associated with the single cracked module.
071357 D
07147/
MCAa 56 Final Report Page 4 Forecast Date for Corrective Action 1.
Construction is proceeding to replace #2 AWG through #20 AWG modules with qualified replacement modules. The modules in the first EPA were replaced on May 11, 1982, with the last EPA scheduled for completion by December 31, 1982.
2.
The cracked module is scheduled to be replaced by August 17, 1982.
3.
All rodent damage is scheduled to be repaired by December 31, 1982.
Submitted by:
J.G. Kovach g
Electrical Group
[
Supervisor Approved by:
M b
.M. Hughes Ann Arbor Project Engineer Concurrence by:
l, u v E.H. Smith Engineering Manager Concurrence by:
M.A. Dietrich Project Quality Assurance Engineer JGK/CS/se(E) 5/13/5