ML20058K648

Responds to IE Bulletin 77-06.Facility Does Not Utilize GE Series 100 Penetrations.Penetrations Have Always Had Positive Nitrogen Pressure Since Initial Const Phase of Facility

ML20058K648
Person / Time
Site:	Monticello
Issue date:	12/05/1977
From:	Wachter L NORTHERN STATES POWER CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
IEB-77-06, IEB-77-6, NUDOCS 9102130412
Download: ML20058K648 (3)

Text

t NSD NORTHERN STATES POWER COMPANY Y-muun

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December 5,1977 O

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_v Mr. James C. Keppler

\\I J Director - Region III Office of Inspection and Enforcement United States Nuclear Regulatory Consaission 799 Roosevelt Road Clen Ellyn, Illinoir 60137

Dear Mr. Keppler:

MOI"IICELLO KUCLEAR GENERATING PLANT Docket No. 50-263 License No. DPR-22 The following is subnitted in reply to IE Bulletin 77-06:

Question 1.0 Do you have contain:x,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 environrent to ensure that the electrical and pressure characteriscies are r.aintained so as to ensure the functional capability as required by the plant's safety analysis report; namely, (1) to ensure adequate functioning of electrical safety-related equipment and (2) to ensure containxnent lesh tightness?

Answer:

The Monticello Nuclear Generating Plant containcent does not utilize the G. E. Series 100 penetration. General Electric has inforned us that the installed penetrations are of the following type:

GE Type KS O2 GE Type ES 03 GE Type KS 04 A total of 14 of these penetrations are presently utilized.

The penetrations utilize an epoxy saalant and a dry nitrogen pressure environment.

Question 1.1 11 ave you experienced any electrical failures with this type of penetration?

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l hr. James G. Keppler

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i Decereber 5,1977 Tage 2-l' Answer:

No electrical failures have been experienced with the above penetrations nor has any degradation of penetration integrity

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been experienced as related to maintaining the integrity of l

the reactor containment structure. Local leak rate testing of these penetrations completed recently demonstrated that little or no leakage existed.

Question 2.0' For those penetrations referenced in Item 1 above, have you maintained the manufacturer's prescribed nitrogen pressure

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at all tir.cs?

l Ansver:

Uc believe that positive nitrogen pressure hac bece f

naintained at all times since initici construction.

It is j

definitely known thrt positive pressure has been caintcineJ i

since the initial refueling outage in 1973.

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Question 2.1 If you have operated the penetrations without maintaining a nitrofen pressure was any degradation of insulation resistance or anomalous component operation detected?

l Ansver:

To the best of knowledge of the plant staff, the penetrationt f

have always had a positive nitrogen pressure since the initial construction phaec of the plant.

In addition, no derradation i

of insulation resistance has been ncted by anomalour corpenent operation.

t Oucrtion 2.2 If no nensuret.cnts were taken during periode when nitrof en j

pressure was not caintained, how vere you assured that the i

insulation resistance vac not degrading or derradeJ7 i

i Ansver:

Not applicabic since a positive nitrogen pressure has been i

caintained.

Question 2.3 How do you determine that circuit insulation resistances values are satisfactorily maintained?

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I Answer:

Circuit insulation resistance values and proper component operation are determined to be properly maintained by the l

Surveillance Test Program. The Surveillance Test Profran i

requires that, on frequenciec varying from daily, weekly, j

nonthly, quarterly, seni-annually up through periods of I

the operating cycle, various functional teste and f

instrunentatien terts be conducted.

Qacrtice 3.0 le there e ne ed, ac deterrined by cither the vcn'or or l

yourself, to t sittain penetrations pressurized during a LOCf.?

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1*J. Janes G. Ecppler Decerher 5, 1977 Pete 3 5

There is not a need to maintain penetrations pressurized Answer:

during a LOCA. The penetrations are double anded in that a seal exists on both the internal and external ends of l

the penetration. Either seal is designed to be capable of withstanding the pressure encountered during a loss of l

r coolant accident.

I Question 3.1 What measures have you taken to ensure that penetrations of this type vill perfore their design function under LOCA conditiono?

(design revienc, analyser or testr) l General Electric Company perforned cnteneive qualification Ansver:

testing both for the electrical properties of the penetration and of the epoxy pottint. corpound and for the properties of the penetration to withstand the environrent j

of the LOCA.

Questien 3.2 Are the ressures that provide this assurance adequate to i

Fatisfy the ConniSSion's refu}ationS7 (CDC 4, AppCndiX A f

l to Part 50; QA Criteria, Appendix E to Part 50)

An.c ve r -

It is our opinion ttiat the ceasures taten for the design i

testing of the electrical penetration assentlies provide f

adequete assurance to satisfy the Cornission's rerulatione.

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Yourc very truly, i

j L.

. Wachter Vice President - Power Production and System Operation cc: -Mr. Victor Stello l

Mr. G. Charnoff f

tiinnesota Pollution Control Agency I

Attention: !!r. J. U. Terman KEC Office of Inspection and Inforcenent Vashington, D.C.

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