ML20215F763

Responds to NRC Re Violations Noted in App R Insp on 870302-06.Corrective Actions:Installation of All Redundant Fusing Circuitry Under Mod 86L927 Completed & Addl Emergency Lighting Procured

ML20215F763
Person / Time
Site:	Prairie Island
Issue date:	05/15/1987
From:	Larson C NORTHERN STATES POWER CO.
To:	Harrison J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
NUDOCS 8706220515
Download: ML20215F763 (5)

Text

y Northern States Power Company 414 Nicollet Mall Minneapolis, Minnesota 55401 Telephone (612) 330-5500 May 15, 1987 1

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l J J Harrison, Chief j

Engineering Branch, Region III

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U S Nuclear Regulatory Commission 799 Roosevelt Road i

Glen Ellyn, IL 60137

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'l PRAIRIE ISLAND NUCLEAR GENERATING PLANT Docket Nos. 50-282 License Nos. DPR-42

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50-306 DPR-60 j

a Response Pursuant to Your Letter Dated April 17, 1987 Regarding Items from the 1

Appendix R Special Inspection of March 2-6, 1987

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This is in response to the violations identified in the Notice of Violation f

Appendix to the subject letter and to the six open and unresolved items

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specifically identified in the letter.

This response discusses action taken j

or planned relative to resolving these items.

j Violations 1.

Sections III.G.2 and III.L.7 of Appendix R, associated circuit common bus areas:

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a.

Fire areas 31, 32, 58, 59, 60, 73, 74 and 75 lacked circuit j

breaker coordination.

Response: A roving fire watch was instituted in these areas on March 5, 1987.

Subsequently, during the current Unit I refueling a

outage, the breaker settings or breaker models have been j

changed for all Unit 1 safe shutdown circuits and associated j

circuits that lacked coordination. Similar changes are planned for Unit 2 during the next scheduled refueling outage i

in January and February, 1988, at which time full comp 1 lance will be achieved.

i For the Unit 1 fire areas of concern -(32, 58, and 60).where compliance has been achieved for all items of concern the fire watch has been discontinued. The fire watch will be continued in the remaining areas until completion of the Unit 2 changes, except during any period when Unit 2 is at cold shutdown.

8706220515 870515 ADOCKOSOOg2 DR 5E01

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'- J J Harrison May 15, 1987 Northern States Power Company Page 2 b.

The D1 Diesel Generator and Hot Shutdown Panels A and B isolation switches do not provide redundant fusing of the 125 VDC control power.

Response: Installation of all redundant fusing circuitry under Modification 86L927 was completed on May 1, 1987. Full compliance has been achieved.

2.

Section III.J of Appendix R, emergency. lighting:

Eight hour emergency lighting was not provided for access and

-egress routes to the Diesel Generator Room No. 1 and inside the Turbine Building operators shack.

Response: Additional emergency. lighting units have been procured for installation in the Turbine Building operators shack.

Installation will be completed prior to July I,1987, at which time full compliance will be achieved. For the diesel I

generator 1 room access route,'the procedure will be revised to identify paths that are presently covered by emergency lighting, by July 1, 1987.

Open ann Unresolved Items (Identified by inspection report item number)

Item 6 - Administrative Controls for Fuse Replacement Response: Fuse data is being entered into the: panel lead' list on the plant informaticn system, which is available to all plant personnel.

Individual panel lists from this load list'are included'at each panel. Administrative instructions'are being. written directing operating and maintenance personnel to install fuses as specified on-this list whenever fuses are removed. The list and instructions-will be complete by June 30, 1987.

Item 7 - High Impedance Faults Response: Modification 87L980 has been initiated and.' design has started for relocating the diesel generator D2 relay panel power source.

Installation is planned for completion by. August' 30, 1987.

Item 8 - High/ Low. Pressure Interfaces Response: Revision 4 to procedure-F5 Appendix ~B, issued May 1, 1987, includes steps to deenergize the' Pressurizer PORV's from' outside the control room.'This action. assures closure..of the FORV's'and prevents' spurious operation.

j J'J Harrison May 15, 1987 l

Page 3 Northem States Power Company i

Also, this revision includes steps to bleed down the

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instrument air header.

Calculations and data from earlier tests demonstrate that the letdown and excess letdown valves will be failed to their closed position in less than eight minutes.

Item 9 - Current Transformer Open Circuit Secondaries Response: This response per the inspection report, was committed to be provided by April 30, 1987.

Per discussions with you, approval was granted to extend the date of response to this item to coincide with this overall response to the i

inspection report.

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1 Following discussions with the Kewaunee Nuclear Generating i

Plant who recently responded to the NRC Staff on the same

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item the following course of action was undertaken. We j

have drafted a report which tabulates which Current

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Transformer (CT) circuits might impact the safe shutdown function. The basis for determining the CT circuits of-concern were:

1.

If a CT circuit enters a safe shutdown related fire j

area had it previously been identified as a safe I

shutdown required circuit and protected as outlined in the Safe Shutdown Analysis?

2.

Is the CT circuit totally contained in a single fire area and therefore cannot affect another fire area?

The report then further addresses those CT circuits in safe l

shutdown related fire areas which did not fall under one of the above categories. These remaining CT circuits will be i

dispositioned on the following basis:

j 1.

The high voltage and associated temperatures that could be generated under CT secondary open circuit conditions.

will cause localized failure due to insulation breakdown, arcing across the windings or arcing across the CT terminals, 2.

The impedance of the CT will limit the voltage such that it will not produce secondary circuit voltages which could cause cable' insulation breakdown, or 3.

An open CT secondary circuit will cause relay operations deenergizing the CT primary.

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.g J J Harrison ~-

=-May 15, 1987

-Fage 4 Northern States Power Company For all circuits to which basis 1 Lor 2~ apply we either have obtained documentation.from, or have been in~ contact with'the manufacturer.

For one manufacturer, the documentation of CT failure does-not explicitly cover all models in' service. This' manufacturer

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has been. contacted regarding applicability of present-i documentation to all models and has verbally confirmed this.

-i For another manufacturer discussions indicate.that' secondary voltage will be limited to signific'antly less'than the withstand

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-voltage capabilities of the. field cables. ~We avait documentation from this manufacturer.

'We will place a final. report, with' supporting manufacturer documentation,_in our Fire Hazards Analysis file as soon.

as the anticipated remaining documentation _is received.-:

1 Our schedule for this'is dependent on the manufacturers.

1 Our conclusion is that the report and documentation will 1

support the present direction and that CT secondary _

circuits will not be an associated circuit / common bus

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concern.

1 Item 11 - Communications Resp

.: Training was conducted on six separate dates commencing on March 9,1987 in conjunction with' the annual-Fire Brigade.

training program.

j The items covered in these training sessions were:

1.

Communication problems that were-observed during the audit walkthroughs.

2.

General hand held radio princip1 w of operation.

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3.

Hand held. radio protocol and procedures.

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4..

Site specific hardware capabilit'ies and. limitations.

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Hardware changes.

The following hardware changes were implemented to correc't-radio communication problems encountered ~during the' 1

Appendix R audit:

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'J Jl Harrison:

May 15,11987 Northem States Power Company Page'5

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The Plant-Repe'ater was_ moved intolthel Auxiliary Building. 'This resulted in better radio signal-penetration and enabled portable-toLportable communica-tions from within the Aux Building to the rest of the.

plant site.

'2.-

The Old Aux Building Transmitter'was installed in the-microwave building. where it will serve as a back-up should.the Plant Repeater become disabled.--

The changes madeLto the plant rad'io communication system hardware were incorporated into the lesson plan ~on May 4, 1987 and all operations personnel were sent a brief overview of.the hardware changesfand' changes.to the hand held radio procedures.

This training'.should provide. adequate information which-will ensure proper hand. held radio communications. The.

hardware changes minimize the number of channels that need to be used, reducing confusion and the potential for crosstalk and interference.

Item 13 - Inadequat "mergency Lighting in. Unit 1 DG RoomL(Fire Area 25, elevatic 95').

Response: Additional emergency lighting units will'be installed in.

this room by July 1, 1987.

C E Larson Vice President Nuclear Generation CEL/ TAP /jlk c: Regional Administrator-III, NRC NRR Project Manager, NRC Resident Inspector, NRC G Charnoff i

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