ML20137F872

Insp Rept 50-245/85-20 on 850708-12.No Violation Identified. Major Areas Inspected:Inservice Insp Program,Diesel Generator Interpolar Connecting Straps & Licensee Actions Taken in Response to GE Svc Info Ltr 402

ML20137F872
Person / Time
Site:	Millstone
Issue date:	08/14/1985
From:	Gray E, Wiggins J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
To:
Shared Package
ML20137F842	List: ML20137F837 ML20137F872
References
50-245-85-20, NUDOCS 8508270112
Download: ML20137F872 (6)

See also: IR 05000245/1985020

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U.S. NUCLEAR REGULATORY COMMISSION

REGION I

Report No. 50-245/85-20

Docket No. 50-245

License No. DPR-21

Priority

Category

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Licensee:

Northeast Nuclear Energy Company

P.O. Box 270

Hartford, Connecticut 06141-0270

Facility Name: Millstone Nuclear Power Station, Unit 1

Inspection At: Waterford, Connecticut

Inspection Conducted: July 8-12, 1985

Inspector :

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E.'H. Gray, Lead Reactor Eng(fi@r

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Approved by:

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J. T. Wiggins, Chief

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Materials and Processes Section, DRS

Inspection Summary:

Inspection During July 8-12, 1985, (Report No. 50-245/85-12)

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Areas Inspected:

Routine unannounced inspection by one region based inspector.

The inspection included areas of the ISI Program, diesel generator interpolar

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connecting straps, and licensee actions taken in response to GE SIL No. 402

ccncerning the potential for cracking of steel components (Torus Vent Header)

by Liquid Nitrogen. The inspection included 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> on site and three hours

of follow-up at the region office.

Results: No violations were identified.

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DETAILS

1.0 Persons Contacted

Northeast Nuclear Energy Company (NNECo)

D. Bergstrom, Senior Control Room Operator

G. Closius, QC/QA Manager-MS#1/2

E. Hernandez, Maintenance Department Planner

• J. Leason, MS #1, ISI Coordinator

G. Mathers, ISI Technician

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• R. Palmieri, OPS Supervisor

• W. Romberg, Station Superintendent

J. Summa, Assistant Engineering Supervisor (Electrical)

J. Quinn, Assistant Supervisory Engineer

• W. Varney, Maintenance Department Superintendent

Northeast 'y 111 ties Service Company (NUSCo)

P. Higgins, Engineer (Inerting System)

• R, West, ISI Coordinator

• Indicates presence at Exit Meeting of July 12, 1985.

2.0 Inservice Inspection (ISI) Program Activities

The present 10 year ISI program started on December 28, 1980.

It is in

accordance with the ASME Code Section XI, 1980 Edition through the winter

1980 addenda, except that the summer 1975 addenda is applicable to

categories BJ, BD,BF,B-G-1 and B-G-2 as stated in the ISI program,

Revision 1, dated August 31, 1984. The licensee's Nuclear Engineering and

Operations (NEO) procedure NEO 2.07 delineates responsibilities for

fulfilling the ISI requirements and is supplemented by procedure QRE 1.10-1.

This procedure prescribes the NUSCO ISI Coordinator responsibilities

including involvement in planning on-site ISI activities.

The present

NDE contractor is EBASCo, who works to the Northeast Utilities NDF.

procedures.

The inspector reviewed the aspects of the ISI program which include

tracking of required examinations, availability of records from the 1984

ISI outage, planning for the present 40 month period, preparation for the

ISI portion of the fall 1985 outage, status reporting format and process-

ing of Non Destructive Examination (NDE) findings as required by procedure

EN 1060G. The overall controls of the ISI program must meet plant

technical specification commitment to ASME Code Section XI and augmented

examination requirements including NUREG 1061. Millstone Unit.1 is in the

first part of the second forty month period of the second 10 year ISI

interval. This forty month period includes two planned refuel outages,

one in the fall of 1985 and the following in 1987. NUREG-1061, Volume 1

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outlines NDE requirements intended to determine the progress of Inter-

granular Stress Corrosion Cracking (IGSCC) in BWR piping with the NDE

scope being dependent on countermeasures taken to prevent or reduce the

IGSCC rate of attack. The outage plan for ISI during 1985 was presented

to the NRC by the licensee in the IGSCC augmented ISI plan memo dated

June 24, 1985.

This outage plan included identification of welds to be

examined to NUREG 1061 and those examinations applicable to meeting the

ASME Code Section XI requirements.

Dbservations were made of archived shop and field radiographs, the storage

area, ultrasonic test blocks, portions of the' ISI data base and of

previous ISI records and documentation.

The steps of review for approval

of NDE procedures and personnel certifications were also reviewed.

The inspector concluded that the administration of the ISI program is

under adequate control to provide for NDE cf the ASME Code Section XI and

the augmented ISI program requirements.

No violations were identified.

3.0 Independent Measurement - Diesel Generator Interpolar Connecting Straps

As a result of the diesel generator (Fairbanks Morse) defects that caused

interpolar connecting strap failure during overspeed at the Calvert Cliffs

Nuclear Plant on May 14, 1985, damage to the stator winding of one diesel

resulted. On May 29 and June 3, 1985, the diesel generator manufacturer

reported under 10 CFR Part 21 the defects of the specific model and

informed licensee's at other nuclear plants supplied the same model.

The

Millstone Unit #1 diesel generator was not identified as the affected

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Fairbanks Morse model.

However, the inspector performed independent

observations to verify that the diesel generator at Millstone Unit No. I

was indeed a different model.

Millstone Unit I has one diesel generator, Fairbanks Morse type TGZDJ,

FR-V-34 which has a gas turbine unit as a backup. Millstone Unit 2 has

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two diesel generators, Fairbanks Morse type TGZDK. The unit 2 diesels

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were observed to not have interpolar connecting straps but does have

damper bars and shorting straps.

The unit I diesel was observed to not

have a visible damper bar circuit but does have a bolted design

interpolar connecting strap.

The interpolar connecting strap is

perpendicular to the generator centerline and is not subject to fatigue

loading similar to that of the Calvert Cliffs TGZDJ generator.

No evidence of degradation was visible on either the Millstone Unit #1 or

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1. 2 diesel generator interpolar connector areas as visible through the

generator screens.

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4.0 TI 2500/12 Actions Taken By The Licensee To Prevent Damage To Plant

Components By Liquid Nitrogen. - Response To GE SIL No. 402.

The boiling water reactor (BWR) Mark I and II containments operate with a

nitrogen drywell atmosphere of less than 4% oxygen.

The nitrogen is

generally provided by vaporizing liquid nitrogen (LN2) from a storage tank

located outside the reactor building. One of the important aspects of

operation of the nitrogen inerting system is to have adequate vaporization

and heating of the LN2 to prevent cooling of carbon steel components

including piping and drywell or Torus components to a temperature below

that where the material will not behave in a ductile manner. The General

Electric Service Information letter (SIL) No. 402 dated February 14, 1984,

outlines this problem and provides the recommendations listed below as

actions to prevent material damage by the nitrogen inerting system.

1.

Evaluate inerting system design

2.

Evaluate inerting system operation

3.

Test for Drywell/Wetwell bypass leakage

4.

Inspect nitrogen injection line

5.

Inspect containment

The region based inspector reviewed NRC inspection reports (50-254/84-02

and 50-254/84-11) which discuss previous activity by the licensee in

meeting the SIL 402 recommendations.

It was noted that the licensee

originally modified the nitrogen supply system in 1973 to prevent damage

by liquid nittogen. The inspector reviewed the drawings (25202-29134-7

and 26009), operations procedure (0P) #311 and engineering correspondence

(GMB-85-R-066 and 059) as applicable to the Nitrogen System. The

inspector also observed the LN2 system including temperature / pressure

interlocks, the steam vaporizer and walked down the nitrogen lines to the

points of entry into the drywell and torus.

The memo GMB-85-R-066

documents licensee review of the nitrogen inerting system design,

potential for injecting low temperature nitrogen into the containment,

orientation of the nitrogen discharge port, operating experience of the

N2 inert.ing system, plant calibration and maintenance schedules, plant

operating procedure, by pass leakage test and visual inspection of the

vent header and downcommer.

Safety features preventing discharge of LN2

into the carbon steel piping include (1) a pressure switch on the steam

vaporizer that prevents LN2 flow if low steam pressure, (2)

temperature

switches preventing LN2 flow if N2 as vaporized is not above approximately

50*F, (3) a flow switch preventing gaseous N2 flow if its temperature is

below 50*F.

On the basis of documents reviewed, discussions with operat-

ing and engineering personnel and observations of the N2 supply system the

inspector concluded that the recommendations of GESIL 402 had been

addressed such that the licensee response to the is considered to be

complete.

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System improvement is planned by providing recycling of a portion of the

N2 gas, reducing the amount needed to be vaporized and thereby further

reducing the risk of having LN2 exposed to those carbon steel components

susceptible to damage.

No violations were identified during evaluation of the licensee actions

pertaining to GESIL 402.

5.0 QA/QC Interactions in Areas Inspected

During inspection of the LN2 vaporizing systeh a tag (trouble report

number 29MI145946, dated 6/29/85) was noted on 7/9/85 identifying a crack

in a copper flange to a 2 inch diameter LN2 supply tube.

To evaluate

control of the identified problems and QA/QC involvement in the mainte-

nance process, the inspector reviewed the trouble report (TR) and the

administrative ccitrol procedure ACP-QA-2.02 C Revision 4.

The procedure

was found to provide for the designation of a lead department, in this

case QC, responsible for activities preceding actual work; however, the

procedure and personnel assignments do not provide for advising the lead

department of the TR.

In this case, the maintenance department PMMS

Planner was aware of the TR and had planned to initiate a work order. The

priority level required that work of the assigned priority generally be

initiated within one week of the date of the TR.

The NRC inspector observed that the procedure (ACP-QA-202-C) permitted a

condition where a designated lead department would not be aware of the

writing of a TR and would not meet the responsibilities of a lead depart-

ment as defined in paragraph 5.0 of the procedure. While a regulatory

violation was not identified in this area, the licensee agreed to review

ACP-QA-2.02C to determine if a revision is required to prevent unnecessary

delay between TR writing and initiation of a work order where a designated

lead department does not monitor TRs.

This item is unresolved

(245/85-20-01).

In the area of ISI, the site QA is involved by audit on a preoutage basis,

review and signoff of the ISI work order, presence during contractor

review by the ISI coordinator and review of NDE procedures and personnel

certifications.

No violation was identified.

6.0 Unresolved Itesm

Unresolved Items are matters about which more information is required

in order to ascertain if they are violations or deviation. An unresolved

item is discussed in paragraph 5.0.

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7.0 Exit Interview

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The inspector met with licensee representatives (denoted in paragraph 1)

at the conclusion of the inspection on July 12, 1985. The purpose,

scope and findings of the inspection were summarized and discussed. At

no time during this inspection was written material provided to the

licensee by the inspector.

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