ML19352A076
| ML19352A076 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 12/02/1977 |
| From: | Ross D JERSEY CENTRAL POWER & LIGHT CO. |
| To: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| IEB-77-06, IEB-77-6, NUDOCS 8103020796 | |
| Download: ML19352A076 (4) | |
Text
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Jersey Central Power & Light Company, Yi C
MACISON AVENUE AT PUNCH BOWL ROAD
- MORRISTOWN.N.J.07960
- 201-539-6111
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General g/
, Pucaic utihties Corporation erire.
December 2, 1977 a
Mr. Boyce H. Grier, Director Office cf Inspection and Enforcement United States Nuclear Regulatory Commission Region !
631 Park Avenue King of Prussia, Pennsylvania 19406
Dear Mr. Grier:
Subject:
Oyster Creek Nuclear Generating Station Dod et No. 50-219 IE Bulletin No. 77-06 The purpose of this letter is to respond to the directives set forth in IE Bulletin No. 77-06 which is concerned with potential problems with containment electrical penetration assemblies.
Item 1.0 Do you have containment electrical penetrations that are of the G. E. Series 100, or are otherwise similar in that they depend upon an epoxy sealant and a dry nitrogen pressure environment to ensure that the electrical and pressure charac eristics are maintained so as to ensure the functional capability as l
required by the plant's safety analysis report; namely, (1) to ensure adequate functioning of electrical safety-related equipment and (2) to ensure contain-ment leak tightness?
i
Response
l The Oyster Creek Nuclear Generating Station containnent does not utilize the G. E. Series 100 electrical penetrations.
The installed penetrations are of the following type:
i G. E. Type NSO2 G. E. Type NS03 G. E. Type NSO4 l
l A total of forty (40) of these penetrations exist in the containment.
The above penetrations utilize an epoxy sealant and a dry nitrogen environment.
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t IE Bullet'in No. 77-06 December 2, 1977
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Item 1.1 t, -
Have you experienced any electrical failures with this type of penetration?
Response
No electrical failures have been experienced with this type of penetration, nor has any degradation of penetration integrity been experienced (i.e., as i
related to maintaining the integrity of the reactor containment structure).
Local leak rate testing of the penetrations completed during the spring 1977 refueling outage demonstrated acceptable local leakage rates.
1 Item 2.0 i
For those penetrations referenced in item I above, have you maintained the manufacturer's prescribed nitrogen pressure at all times?
Resconse The manufacturers of these penetrations did not prescribe that a nitrogen pressure be maintained at all times, but rather that at the completion of installation testing, the penetration contain 15 psig of dry nitrogen. The Oyster Creek penetrations have been pressurized to 35 psis for local leak rate testing during each refueling outage.
Each penetration was then isolated with dry nitrogen at 35 psig minimum and no surveillance to main-tain this pressure was accomplished until the next local leak rate testing period.
It is, therefore, not known what the exact minimum dry nitrogen pressure was, except that the penetration did contain dry nitrogen.
Presently, six (6) of the forty (40) penetrat ions contain less than 5 psig dry nitrogen.
These penetrations contain coaxial and triaxial cables which were insulation resistance tested and were found to be satisfactory during the last refueling outage.
Item 2.1 If you have operated the penetrations without maintaining a nitrogen pressure, was any degradation of insulation resistance or anomalous component operation detected?
Response
The Oyster Creek Station has not detected any degradation of insulation resistance or anomalous component operation.
Item 2.2 If no measurements were taken during periods when nitrogen pressure was not c
maintained, how were you assured that the insulation resistance was not degrading or degraded?
IE Bulletin No. 77-06 December 2, 1977 Resconse The Oyster Creek Station was assured that the insulation resistance was not degraded by (1) the continued satisfactory operation of the plant without anomalous component operation and (2) the surveillance test program of the nuclear safety equipment which required that on frequencies varying from daily, weekly, monthly, quarterly, semiannually, up through periods of the operating cycle, that various functional tests and instrumentation tests be conducted.
Also, during insulation resistance testing accomplished in the past after plant modifications and during surveys, the total system insulation resistances (above 100 megehm) were satisfactory. This testing has not been previously documented.
item 2.3 How do you determine that circuit insulation resistances values are satisfactorily maintained?
Response
The circuit insulation resistance values and proper component operation are determined to be properly maintained by both the survelliance test program, and the various insulation resistance testing as noted in response 2.2.
Item 3.0 is there a need, as determined by either the vendor or yourself, to maintain penetrations pressurized during a LOCA7 Resconse There is not a need to maintain penetrations pressurl:ed during a LOCA.
The penetration is double ended in that a seal exists on both the Internal and external ends of the penetration.
Either seal is designed to be capable l
of withstanding the pressure encountered during a loss of coolant accident.
l l
Item 3.1 What measures have you taken to ensure that penetrations of this type will perform their design function under LOCA conditions?
(design reviews, analyses or tests)
Resconse The Burns & Roe, Inc. Purchase Specification S-2299-52 (Reference; FDSAR Amendment 15, Section ill, Paragraph 4.2, and Section VI, Paragraph 2.2) j required extensive qualification testing both for the electrical properties l
of the penetration and the epoxy potting compound and for the properties j
of the penetration to withstand the environment during a LOCA.
1 w
o IE Bulletin No. 77-06 December 2,1977 Item 3.2 Are the measures that provide this assurance adequate to satisfy the Commis-ston's regulations (GDC 4, Appendix A to Part 50; QA Criteria, Appendix B to Part 50)?
Response
The Oyster Creek Station's containment electrical penetrations were tested prior to the Commission's requirements for compliance to either the GDC 4, Appendix A to Part 50 or the QA Criteria, Appendix B to Part 50.
- However, it is our opinion that the testing does meet the requirements of GDC 4 and certain portions of the QA Criteria.
The exact portions of the QA Criteria met will be determined within ten days.
yours very truly, 0) 7&f Y!Gjfnu
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Donald A. Ross, Manager Generating Stations-Nuclear es
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