ML20207J272
| ML20207J272 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 06/30/1986 |
| From: | Foster D GEORGIA POWER CO. |
| To: | Grace J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| REF-PT21-86, REF-PT21-86-284-000 GN-971, PT21-86-284, PT21-86-284-000, NUDOCS 8607280201 | |
| Download: ML20207J272 (3) | |
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l Georgia Fdwer Company Fast Office Box 282 Waynesboro, Georgia 30830 Telephone 404 554 9961. Ext. 3360 404 724-8114, Ext. 3360 m
Georgia Power D. O. Foster c
es ent the Soutt e n e trc system p
June 30, 1986
[
o United States Nuclear Regulatory Commission C
Region II File: X78G01-M100 Suite 2900 Log:
GN-971rc 101 Marietta Street, Northwest Atlanta, Georgia 30323 14 Vogtle Electric Generating Plant-Units 1 and 2;50-42d 50-425;
Reference:
Spliced Instrument Cables; Letter GN-888 dated May 1, 1986 Attention: Mr. J. Nelson Grace In previous correspondence on this subject, Georgia Power Company described a potentially reportable concern whereby remov:1 of sections of the protective jacket from certain instrument cables during termination operations may have an adverse impact on the environ:nental qualifications of the cable conductors. Georgia Power Company has completed its evalua-tion and concluded that a reportable condition as defined by the reporting criteria of Parts 10 CFR 50.55(e) and Part 10 CFR 21 does exist.
Based upon NRC guidance in NUREG-0302 Revision 1 and other correspondence concerning duplicate reporting, Georgia Power Company is reporting this condition pursuant to Part 10 CFR 50.55(e).
A summary of the evaluation is attached.
This response contains no proprietary information and may be placed in the NRC Public Document Room.
8607280201 860630 Yours truly, /
j r
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PDR ADOCK 05000424 oster REF/D0F/tdm Attachment xc:
U. S. Nuclear Regulatory Commission Document Control Desk Washington, D. C.
20555 J. H. Miller R. A. Thomas L. T. Gucwa J. P. O'Reilly D. R. Altman C. W. Hayes G. F. Head P. R. Bemis G. A. McCarley R. E. Conway J. A. Bailey D. S. Read J. T. Beckham
- 0. Batum-Sr. Resident (NRC)
R. H. Pinson G. Bockhold C. S. McCall (OPC)
P. D. Rice C. E. Belflower J. E. Joiner (TSLA)
B. M. Guthrie J. F. D'Amico D. C. Teper (GANE)
D. E. Dutton E. D. Groover NORMS 1
EVALUATION OF A P0TENTIAL REPORTABLE CONDITION SPLICED INSTRUMENT CABLES Initial Report: On April 2, 1986, Mr. R. E. Folker, Vogtle Quality Assurance Engineer, informed Mr. M. V. Sinkule of the USNRC-Region II of a potentially reportable condition concerning the splicing of instrument cables inside containment.
Sections of the protective jacket were removed from instrument cables which were qualified with their insulated conductors enclosed within a cable jacket.
This condition could potentially affect the environmental qualification of the instrument cables.
In subsequent correspondence, Genrgia Power Company indicated the NRC would be informed of the results of the evaluation of this condition by June 30, 1986.
Background Information: This condition concerning the protection of instrument cables inside areas subject to a harsh environment was identified in deviation report ED-11309.
The deviation report indicated that cables were spliced and that no design detail existed for cases where the outer jacket of the cable had been removed.
A broadness review indicated that this condition could exist inside contaiment and in main steam isolation valve (MSIV) areas of the plant.
This review identified approximately 120 instrument cables for the Vogtle Electric Generating Plant - Unit 1 which are located in the accident environment that required either one end or both ends of the cable
)
to be sealed.
This is documented on a construction specification change notice (CSCN) no. 476 to specification X3AR01.
The function of this instrument cable inside the containment areas and in the MSIV areas is to transmit instrument signals.
The signal is received by current-to-voltage converters, controllers, and bi-stables which are located outside the containment and MSIV areas.
Instrument cables must be installed in the same manner and configurations for which they were qualified in order to meet the total instrument loop accuracy requirements.
A deviation during cable installation from the qualified configuration may result in an erroneous instrument reading which could mislead an operator.
Engineering Evaluation: The instrument cables were qualified for safety-related Class 1E applications including conditions during a loss-of-coolant accident (LOCA), with the jacket intact, that is, no insulated conductors exposed to moisture, chemicals, etc.
During termination of these cables, the cable jackets were stripped back to a distance which, after termination, left the insulated conductors exposed to the environment.
The exposure of the insulated conductor to an accident environment could theoretically degrade the conductor insulator to a point which will allow insulation leakage current between the conductors or between the conductor and ground.
This could cause a degradation of the transmitted instrumentation signal.
The contribution of cable leakage current and its effect on overall instrument accuracy for the subject cable terminations is unknown because test results are not available for the stripped cable jacket configuration.
The cable qualification program was conducted with the cable jacket intact; so insulated conductors were not exposed to moisture, chemicals, etc.
The effect on the instrument loop accuracy cannot be estimated without test results.
This condition represents a communication or information transmittal concern.
At the time this cable was installed, the construction specification did not contain information that the outer jacket had to remain intact (for environmental protection) up to the termination point.
Thus, no instructions prevented construction personnel from removing the outer jacket.
Also, no instructions were provided to indicate that, after removal of the cable jacket, Raychem heat shrinkable tubing splice kits should have been utilized for jacket repair.
Review for a Quality Assurance Program Breakdown: A review indicated that this condition represented a transmittal of information concern and did not constitute a significant breakdown of the quality assurance program of Georgia Power Company or that of Bechtel Power Corporation.
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Conclusion:==
Georgia Power Company has reviewed this condition and determined that a reportable condition as defined by the reporting criteria of Part 10CFR50.55(e) and Part 10CFR21 does exist.
The construction and design documents did not contain information that the outer jackets had to remain intact to ensure the environmental qualification of the component.
Bechtel Power Corporation should have included this information in the appropriate documents.
Corrective Action:
1.
In order to rebuild the stripped portion of the cable jacket, and to i
maintain the cable qualification, construction specification X3AR01 was revised via CSCN no. 476 delineating the requirement of installing and retrofitting the Raychem heat shrinkable tubing splice kits for jacket replacement and/or repair.
2.
The requirement is applicable to those instrument cables identified by deviation report ED-1.2247 to have been improperly spliced and are required to remain functional during the first three hours of a LOCA.
The requirement will also cover any fixes to similar installation problems that will occur in the future.
The retrofitting work is in progress and the closing of deviation report ED-12247 will signify the completion of work.
i 3.
A construction specification revision or construction specification change notice will be prepared for the Vogtle Electric Generating Plant - Unit 2.
This will ensure the Unit 2 instrument cables are properly protected.
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