ML19343C334
| ML19343C334 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 12/02/1977 |
| From: | Switzer D NORTHEAST NUCLEAR ENERGY CO. |
| To: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| IEB-77-06, IEB-77-6, NUDOCS 8103090527 | |
| Download: ML19343C334 (9) | |
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- s A TOl CONNECT CUT C6'M 2MMMM NORTHEAST NUCLEAR ENERGY COMPANY A NORTPiEAST UTIUTIES COMPANY December 2, 1977 Docket Nos. 50-245 50-336 Mr. Boyce H. Grier, Director Office of Inspection and Enforcement Region I U. S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, PA 19406
Reference:
Inspection and Enforcement Bulletin No. 77-06,
" Potential Problems with Containment Electric Penetration Assemblies"
Dear Mr. Grier:
In accordance with the above referenced Inspection and Enforcement Bulletin, Northeast Nuclear Energy Company provides the requested information for Millstone Units 1 and 2 in Attachments #1 and #2 respectively.
Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY D. C. Switzer President DCS:WJD/kwc Attachments
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MILLSTONE UNIT NO. 1 RESPONSES TO NRC IE BULLETIN 77-06
' Question 1.0 Do you have contain=ent 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 insure that the electric and pressure characteristics are maintained so as to insure the functional capability as required by the plant's safety analysis report; namely (1) to insure adequate functioning of electrical safety related equipment and (2) to insure contain-ment leak tightness?
= Answer Containnent electrical penetrations of the G.E. series 100 type are not utilized. The installed penetrations are G.E. types NS02, NS03 and NSO4 which are'similar to the series 100 in that they depend upon an epoxy sealant and a nitrogen pressure to ensure containment leak tightness. These penetrations employ uninsulated transition splices embedded in the epoxy sealant.
Question 1.1 Have you experienced'any electrical' failures with this type of penetration?
- Answer No electrical failures of.the installed penetrations have been experienced.
Question-2.0 For~those penetrations referenced in ItemL1 above, have you maintained the manufacturers prescribed nitrogen pressure at all_ times?-
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Answer Nitrogen pressure has not been maintained at any time.
Question 2.1 If you have operated the penetrations without maintaining a nitrogen pressure, was any degradation of insulation resistance or anomalous component operation detected?
Answer No anomalous component operation has been experienced and therefore the need to check insulation resistance has not been a requirement.
Question 2.2:
If no measurements were taken during periods when nitrogen pressure was not maintained, how were you assured.that the insulation resistance was not
' degrading.or degraded.
Answer Historically,f degradation of. insulation resistance has not been a problem
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and therefore no measures were implemented to check for.such~ degradation.
Quest 1on 2.3 How do you determine that circuit' insulation resistance values are. satis-factorily maintained?
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Answer Duringeachrefuelingshutdown,insulationresistancetoground}checksare-
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made on many of'the circuits which access the' drywell via penetrations.
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i Qu stion 3.0 Is there a need, as determined by either the vendor or yourself, to =aintain penetrations pressurized during a LOCA?
Answer There is no need to maintain the installed penetrations pressurized during a LOCA. The penetration is double ended in that both a seal exists on the internal ~and external ends of the penetration.
Either seal is designed to be capable of withstanding the pressure encountered during a LOCA.
Question 3.1 lihat neasures have you taken to insure that penetrations of this type will
. perform their designed function under LOCA conditions (design reviews, analyses or testa)?
Answer The purchase specification for the installed penetrations required the vendor to perform LOCA environment testing to qualify the penetrations for their designed function. lRecent discussions with the vendor (G.E.) have confir=ed
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.that this testing was perfor=ed. Documentation relating to these tests has lbeen requested from G.E.
Question 3.2 Are the measures'that provide this assuranceLadequate to satisfy the-commissions regulations (GDE 4, Appendix A to Part 50; QA Criteria, Appendix JB to Part 5)?'
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An:wsr It is believed that the =easures taken as outlined in 3.1 above, are adequate to =eet the intent.of the con =ission's regulations.
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- 12/2/77
m IIILLSTONE UNIT No. 2 RESPONSES TO NRC IE BULLETIN 77-06 Question 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 insure that the electric and pressure characteristics are maintained so as to insure the functional capability as required by the plant's safaty analysis report; namely, (1) to insure adequate
- functioning of electrical safety relat2d equipment and (2)'to insure contain-ment leak tightness?
Answer
-Containment electrical penetrations of the G.E. _ series 100 type are installed and utilized.
Question 1.1
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Have you experienced any electrical failures with this type of p'enetration?
Answer Electrical failures. involving conductor to conductor interactions have recently been: experienced.
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- Question-2.0 For those penetrations referenced in Item 1 above, have you maintained the manufacturers prescribed nitorgen pressure at all times?
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Answcr Initially, a nitrogen pressure as recon = ended by the =anuf acturer was maintained until approxi=ately one year ago when, following discussions with the =anufacturer, the nitrogen pressure was allow.d to decay. Nitrogen pressure was reestablished early in October 1977 when the f ailures addressed in 1.1 were experienced.
Question 2.1 If you.have operated the penetrations without maintaining a nitrogen pressure, was any degradation of insulation resistance or anomalous component opera-tion detected?
Answer Early in October 1977, af ter operating for. approxi=ately 10 =enths without nitrogen pressure, ano=alous cocponent operation was experienced and degra-dation. of insulation ~ resistance was detected.
Question 2.2
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If no measurements were taken during periods when nitrogen pressure was not maintained, how were you assured that the insulation ~ resistance was not
-degrading or deg:aded?
Answer' 1 Prior to the detection of anomalous component operation which in turn led to the detection of insulation resistance degradation,-there was no need to Leheck for such degradation.
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Question 2.3 How do you determine that circuit insulation resistance values are satisfacco-rily maintained?
Answer Since early October 1977, periodic checks of insulation resistance involving spare and active conductors has been perfor=ed to deter =ine the acceptability of continued use of the conductors.
Question 3.0 Is there a need, as determined by either the vendor or yourself, to maintain penetratisns pressurized during a LOCA?
Answer There is no need to maintain the installed penetrations pressurized during a LOCA. The penetration seal is designed'and has been tested to withstand the pressure encountered during a LOCA.
Question 3.1 What measures have you taken to insure that penetrations of this type will perform their designed function under LOCA conditions (design reviews, analyses or tests)?-
Answer The purchase specification for the installed penetrations required the vendor to perform LOCA environment testing to-qualify the penetrations for their
=desigt.ed function.
These tests'were performed and the associated documentation
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is.in our possession.
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Question 3.2 Are the measures that provide this assurance adequate to satisfy the cecaissions regulations.(GDC 4, Appendix A to Part 50; QA Criteria, Appendix B to Part 5)?
Answer It is believed that the measures taken as outlined in 3.1 above, are adequate to meet the intent of the comission's regulations.
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NORTHEAST NUCLEAR ENERGY COMPANY 223 * #
A NO~ITNEAST UTILIT;ES COMPANY I
December 2, 1977 Docket Nos. 50-245 50-336 Mr. Boyce H. Grier, Director Office of Inspection and Enforcement Region I U. S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, PA 19406
Reference:
Inspection and Enforcement Bulletin No. 77-06,
" Potential Problems with Containment Electric Penetration Assemblies"
Dear Mr. Grier:
In accordance with the above referenced Inspection and Enforcement Bulletin, Northeast Nuclear Energy Company provides the requested information for Millstone Units 1 and 2 in Attachments #1 and #2 respectively.
Very truly yours, t
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NORTHEAST NUCLEAR ENERGY COMPANY t
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D. C. Switzer '
President DCS:WJD/kwc i
Attachments DUPLICATE DOCUMEl j
Entire document previously entered into system under:
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%/03090S27 ANo No. of pages.:
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