United States Nuclear Regulatory Commission - Protecting People and the Environment

ACCESSION #: 9801020165

                                        Illinois Power Company

                                        Clinton Power Station

                                        P.O. Box 678

                                        Clinton, IL 61727

                                        Tel 217 935-5623

                                        Fax 217 935-4632


     POWER                              John G.  Cook

                                        Senior Vice President

An Illinova Company                     U-602997


                                        December 22, 1997

Docket No.  50-461                      10CFR21.21

Document Control Desk

Nuclear Regulatory Commission

Washington, D. C. 20555

Subject:  10CFR21 interim Report 21-97-051: Improper Cable Resistance

          Values Used in Design of the AC and DC Electrical Distribution


Dear Madam or Sir:

     On October 23,1997, Illinois Power (IP) identified that at least

five electrical voltage calculations for the design for the Alternating

Current (AC) and Direct Current (DC) electrical distribution system used

improper cable resistance data provided by Sargent & Lundy (S&L) in Table

B of S&L Standard ESA-102, "Electrical Engineering Standard for

Electrical and Physical Characteristics of Class B Electrical Cables."

The standard provided the cable resistance used for determining cable

tray loading and voltage drop calculations that established the design

bases of Clinton Power Station (CPS).  Per S&L Power and Control Cable

Specification STD-EA-253, "General Specification for Power and Control

Cable Insulated with Ethylene-Propylene Rubber," CPS cables with voltage

ratings below 5 Kilovolts (KV) have "tin-coated" copper conductors;

however, Table B of Standard ESA-102 provides resistance data for 4C

uncoated" copper conductor cables.  Coated cables have higher resistance

values than uncoated cables.  Higher resistance values yield slightly

lower equipment terminal voltages than presently established in at least

five calculations.  Condition Report 1-97-10-414 was initiated to track

the investigation and resolution of this issue.

     IP determined this issue was potentially reportable under the

provisions of 10CFR21 on October 25,1997.  CPS engineering personnel

identified that the values in S&L standard ESA-102 are lower than actual

cable impedance shown on the cable vendor test reports and cable

manufacturer literature for cable purchased for CPS.


                                                       Page 2

     IP's evaluation of this issue under the provisions of 10CFR21 has

not been completed.  IP does not have a firm date for resolving this

issue, but will provide, as a minimum, an update on the resolution

progress by January 19, 1998.

     Additional information about this issue may be obtained by

contacting A. B Haumann, Engineering Projects, at (217) 935-8881,

extension 4078.

                                        Sincerely yours,

                                        J. G. Cook

                                        Senior Vice President


cc:  NRC Clinton Licensing Project Manager

     NRC Resident Office, V-690

     Regional Administrator, Region III, USNRC

     Branch Chief, Region III, USNRC

     Illinois Department of Nuclear Safety

     INPO Records Center

     Sargent & Lundy

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