ML20246D564

Forwards Corrective Action Insp Rept 50-353/89-201 During Wk of 890424 Re Independent Design Assessment.Assessment Provided Needed Addl Assurance That Plant Design Met Licensing Commitments

ML20246D564
Person / Time
Site:	Limerick
Issue date:	08/23/1989
From:	Varga S Office of Nuclear Reactor Regulation
To:	Hunger G PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
Shared Package
ML20246D568	List: IR 05000353/1989201 ML20246D564
References
NUDOCS 8908280189
Download: ML20246D564 (6)

See also: IR 05000353/1989201

Text

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. UNITED STATES

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NUCLEAR REGULATORY COMMISSION

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Dbckht Nui 50-353:

I ' Mr.f George' A'.! Hunger, Jr.

Director-Licensing

> ATTN:~ Correspondence Control Desk:

Philadelphia Electric Company

2301 Market Street

' Philadelphia. Pennsylvania 19101'

(Dear Mr. Hunger:

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> SUBJECT:- CORRECTIVE ACTION INSPECTION OF THE INDEPENDENT DESIGN

ASSESSMENT AT t.IMERICK GENERATING STATION UNIT 2 REPORT

50-353/89-201:

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As part of, its plan. to monitor Philadelphia. Electric Company's-(PECO's) " Program

. for the Independent Design and Construction Assessment (IDCA) of. Limerick Unit 2 "

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the hRC staff conducted 6. corrective action inspection of the' independent design

assessment (IDA). . This inspection took place at the offices of the architect-

engineer, Bechtel Power Corporation, located in San Francisco, California, during

the week of April 24, 1989. The exit meeting was held on April 28, 1989..

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The purpose of this inspection was to assess.the validity of the design assessment.

report issued by the independent contractor, Stone and Webster Engineering Company

(SWEC), on April 112,1989. -The inspection team's approach included a ruiew of 64 -

. selected design observation reports .(DORS) to ensure that each issue identified

had received an appropriate response by the architect-engineer and that a proper.

. evaluttion of each response had been performed by the independent contractor. Also,

the inspection team: verified that the corrective actions resulting from the design-

observation. reports had been performed or were scheduled to be completed by PECO.' .j

The inspection team was satisfied with the methods, quality and comprehensive-

ness of the IDA and concluded-that the IDA provided the needed additional'

assurance that the design of Limerick Unit 2 met its licer. sing commitments. i

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This conclusion was based on the NRC's multi-inspection overview of the IDA' 3

l program,- the independent contractor's similar conclusion, and commitments from - l

- PECO which were occumented in letters to the NRC dated M&y 16 and May 25, 1989' i

As a result of the inspection team's review, PECO has connitted to perform the -l

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u, (following. .

l  ;(1) Evaluation of. the effect of- grid voltage swing to ensure that spuricus

separation of. the onsite sufety-related buses from the grid does not

occur for the conditions defined in the inspection report (See DDR 103).

(2) Evaluation of the sizing of the thennal overload relay heaters for

safe-shutdownapplications(Seed 0R039).

(3) Evaluation of.the vital battery end-of-life capacity considering a '

nondetectable high impedance fault on the ac side of the inverter ,

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(See DDR 087). g (

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Mr. George A. Hunger, Jr. -2- AUG 231989

PECO has connitted to complete the aforementioned activities before exceeding

5 percent power for items (1) and (2), and before loading fuel for item (3). For

these three items, PECO is requested to respond in writing within 60 days describing

the details of their evaluation, the conclusions, and the associated corrective

actions, if any.

Additionally, the Hazards Program Evaluation Supplement which was distributed

on May 17, 1989, was reviewed and found acceptable by the staff, and no associated

inspection is planned.

If you have any questions, please contact me or the IDCA coordinator, Gene Imbro,

at (301) 497-0954.

Sincerely.

Oricinal signed by

Steven A. Varga, Director

Division of Reactor Projects I/II

Office of Nuclear Reactor Regulation

Enclosures:

1. Executive Summary

2. Inspection Report 50-353/89-201

cc w/ enclosures:

See next page

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Mr. Geo'rge A. Hunger, Jr. Limerick Generating Station ,

. Philadelphia ' Electric Company Units 1 & 2 i

)

\ cc:

Troy B. Conner, Jr., Esquire Mr. Ted Ullrich '

Conner and Wetterhahn Manager - Unit 2 Startup

1747 Pennsylvania Avenue, N.W. Limerick Generating Station i

Washington, D.C. 20006 P.O. Box A

Sanatoga, Pennsylvania 19464

I Mr, Rod Krich 57-1 Mr. John Doering

J Philadelphia Electric Company Superintendent-0perations I

2301 Market Street Limerick Generating Station

Philadelphia, Pennsylvania 19101- P.O. Box A '

Sanatoga, Pennsylvania 19404

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Mr. David Hcnan N2-1 Thomas Gerusky, Director

Philadelphia Electric Company Bureau of Radiation Protection

2301 Market Street PA Dept. of Environmental Resources

Philadelphia, Pennsylvania 19101 P. O. Box 2063

Harrisburg, Pennsylvania 17120

Mr. Graham M. Leitch, Vice President Single Point of Contact

Limerick Ger erating Station P. O. Box 11880

Post Office Box A Harrisburg, Pennsylvania 17108-1060

Sanatoga, Pennsylvania 19464

Mr. James Linville Mr. Philip J. Duca

U.S. Nuclear Regulatory Commission Superintendent-Technical

Region 1 Limerick Generating Station

475 Allendale Road P. O. Box A

King of Prussia, PA 19406 Sanatoga, Pennsylvania 19464

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Mr. Thomas Kenny

Senior Resident Inspector

U.S. Nuclear Regulatory Commission .

P. O. Box 596 l

Pottstown, Pennsylvania 19464

Mr. Joseph W. Gallagher

Vice President, Nuclear Services ,

Philadelphia Electric Company i

2301 Market Street

Philadelphia, Penrisylvania 19101 i

Mr. John S. Kemper

Senior Vice President-Nucler,r

Philadelphia Electric Compr.ny i

2301 Market Street

Philadelphia, Pennsylvan',a 19101

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, EXECUTIVE SUMMARY

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INSPECTION REPORT 50-353/89-201

LIMERICK GENERATING STATION, UNIT 2

The NRC inspection team has monitored each of thu .iesign and construction

aspects of the Limerick independent design and construction assessment (IDCA)

in three phases: (1) preparation of review plans, (2) implementation of the

review plans and performance of the review, and (3) evaluation of the final

IDCA report, including assessment of the corrective actions. This inspection

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was the third phase of the independent design assessment (IDA) and was con-

ducted at the offices of the architect-engineer, Cechtel Power Corporation,

located in San Francisco, California.

The inspection tean, assessed the validity of the design assessment report by

reviewing 64 of the 118 design observation reports (DORS). The review focused

on the appropriateness of the Bechtel response to Stone and Webster Engineering

Company (SWEC) findings as well as the appropriateness of SWEC's evaluation of

Etetel's response. Additionally, the inspection team reviewed implementation of

'M associated corrective actions.

Of the 118 design observation reports, Bechtel and SWEC could not agree on

resolution of 6 of these items. The inspection team reviewed these items,

which are sucmarized below:

For D0R 015 regarding the generic qualification of a radiation shielding

program, for D0R 043 regarding use of a exponential temperature decay

1or piping thermal analysis, and for DDR 097 regarding heat loads

for control room cooling under emergency conditions, the inspection

team decided that no additional action was necessary to resolve

the iswes identified, and these items are censidered closed.

DOR 039 questioned the validity of not including heater tolerances

and minimum operating voltages in the sizing of motor thermal

overload relay heaters. The inspection team concurred with the

finding and requested PECO to evaluate the sizing of thermal

overload relay heaters, includirg the effects of low voltage, high

ambient temperatures, and negative tolerances for all continuously

running 480-volt motors required for safe shutdown. PEC0's letter of

May 16, 1989, committed to perfonn this evaluation before exceeding

5 percent power.

DDR 103 requested that the grid swing minimum voltages be analyzed to

confirm that spurious separation of the onsite safety-related buses

from the grid would not occur. The inspection team concurred with the

finding and defined the condition to be analyzed as a single source of

offsite power supplying both units, the load tap changer at its most

unfavorable position before the event, a loss-of-coolant-accident (LOCA)

in one unit and safe shutdown in the other unit, and a dip in the grid

voltage as a result of a loss of another offsite unit when the voltage

on the grid was at a normal minimum value. PECO's letter of May 16,

1989 connitted to revise the voltage regulation study for a grid voltage

swing evaluation before exceeding 5 percent power, and the staff expects

the aforementioned scenario to be completely reviewed.

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DdR 113. questioned the design of the diesel generator ground fault

annunciation. The inspection team agreed that the current design does

not violate any licensing commitment or regulatory requirement. However,

the inspection team viewed this as a poor design practice because it was

not consistent with standard industry practice, it increased the risk of

a fire, and the associated annunciator circuit would be unreliable subse-

quent to a LOCA. PECO should re-evaluate the sizing of the associated

diesel generator ground fault resistor, considering the aforementioned

shortcomings of the present design.

In addition to the 6 open items identified by SWEC, the inspection team

reviewed on a sampling basis 58 other DORS and was generally well satisfied

with their resolution. As a result of the inspection team's review, two items

were discussed at the exit meeting which required PECO action and are discussed

below:

D0R 021 identified that no formally issued procedure existed for the

performance of balance-of-plant safety-related instrument setpoint

calculations. As a result of this finding, the inspection team

identified related issues which were adequately addressed in PECO's letter

dated Merch 25, 1989, and resulted in the need for a final safety

analysis report (FSAR) change and revision to instrument setpoint data

sheets for increased process tolerance. Based on PEC0's response, this

item is closed.

DDR 087 verified ti:at the vital battery had sufficient end-of-life

(E0L) margin. However, the inspection team identified that the

effect of a high impedance fault on the discharge of the inverter

was not considered in the EOL margin evaluation. PECO committed

in its letter dated May 16, 1989, to perform the associated calculat on d

before fuel load.

The inspection team concluded that the SWEC IDA review was thorough, and the

results provide additional assurance regarding the adequacy of the Limerick

Unit 2 design process.

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