United States Nuclear Regulatory Commission - Protecting People and the Environment

ACCESSION #: 9603210271

                                             Illinois Power Company
                                             Clinton Power Station
                                             P. O. Box 678
                                             Clinton, IL 61727
                                             Tel 217-935-5623
                                             Fax 217-935-4632

                                             Wilfred Connell
ILLINOIS                                     Vice President

                                             March 13, 1996

Docket No.  50-461                            10CFR21.21

Document Control Desk
Nuclear Regulatory Commission
Washington, D.C.  20555

Subject:  10CFR21 Interim Report 21-96-001: Ideal Generators
          Installed with Emergency Diesel Generators Have
          Generator Rotor Mass Greater Than Originally Calculated

Dear Sir:

     On January 15, 1996, Illinois Power (IP) identified a condition
involving the Divisions 1 and 2 Emergency Diesel Generators (EDGs) as
potentially reportable under the provisions of 10CFR21.  Specifically,
Condition Report (CR) 1-96-01-029 was initiated to identify that Ideal
Electric, the manufacturer of the generator portion of the EDGs, had
discovered that the mass of the generator rotors had been incorrectly
calculated.  The revised calculation shows a larger rotor mass and
rotational inertia.

     IP has completed an evaluation of the impact of this condition on
the seismic qualification of the diesel generator units and has concluded
that the increase in mass has no adverse impact on the units.  However,
IP has not completed an evaluation of the impact on the frequency and
torsional analysis of the units.  IP purchased the EDG units from Stewart
& Stevenson.  The generators are Ideal model numbers SA6-50 and SA6-44,
and Ideal drawings B-MED-221 and B-MED-217.

     The evaluation for reportability under the provisions of 10CFR21 is
currently scheduled to be completed by July 12, 1996.  Following
completion of the evaluation, IP will report the results to the NRC in a
final report.  Additional information regarding this issue may be
obtained by contacting M. M.  Gandhi, Engineering Projects, at (217) 935-
8881, extension 4082.

                                   Sincerely yours,

                                   Wilfred Connell
                                   Vice President


                                                       Page 2

cc:  NRC Clinton Licensing Project Manager
     NRC Resident Office, V-690
     Regional Administrator, Region III, USNRC
     Illinois Department of Nuclear Safety
     INPO Records Center
     Ideal Electric
     Steward & Stevenson


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