Part 21 Report - 1997-141
ACCESSION #: 9703060182
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
POWER U-602704
4F.140
WC-123-97
February 27, 1997
Docket No. 50-461 10CFR21.21
Document Control Desk
Nuclear Regulatory Commission
Washington, D. C. 20555
Subject: 10CFR21 Final Report 21-97-004: Phoenix Power Systems Regulated
Power Transformer Supplied and Qualified by United Controls
International is Not Capable of Operating Over the Required
Output Range
Dear Madam or Sir:
On January 7, 1997, Illinois Power (IP) initiated Condition Report
1-97-01-062 due to regulated power transformer 1AP75ERT tripping several
times for no known reason. The transformer was installed under Plant
Modification AP-028 to resolve a degraded voltage relay setting
condition. The first trip occurred after the modification was released
for operations. An investigation of the cause of the trips determined
that the transformer tripped off with the addition of step load from a
low or no load condition. IP has been advised by the manufacturer that
the transformer units require a minimum load of 2 amps per phase to
remain stable, contrary to the purchase specification which requires
voltage control from the no load condition to unit rating. The safety-
related 120-volt distribution panel fed by the transformer de-energizes
when the transformer trips. This issue was identified as potentially
reportable under the provisions of 10CFR, Part 21.
The regulated power transformer is model number P3C015C6/EAN
Guardian Power Conditioner manufactured by Phoenix Power Systems. The
transformer was qualified Class 1E and supplied to Clinton Power Station
by United Controls International.
On the basis that the transformer does not meet the requirements of
the procurement document, and the failure of the transformer to perform
its function could result in the loss of power to safety-related
equipment loads, IP has concluded that this issue is reportable under the
provisions of 10CFR, Part 21.
U-602704
Page 2
IP is providing the following information in accordance with
10CFR21.21(c)(4). Initial notification of this matter will be provided
by facsimile of this letter to the NRC Operations Center in accordance
with 10CFR21.21 (c)(3) within two days of the date the responsible
officer signs this letter.
(i) Wilfred Connell, Vice President of IP, Clinton Power Station,
Post Office Box 678, Clinton, Illinois, 61727, is the
responsible officer notifying the Nuclear Regulatory Commission
of a condition reportable under the provisions of 10CFR, Part
21.
(ii) The basic component involved in this condition is a dry type
regulated power transformer, Phoenix Power Systems model number
P3C015C6/EAN Guardian Power Conditioner.
(iii) The regulated power transformer was manufactured by Phoenix
Power Systems, San Diego, California. The unit was qualified
Class 1E and supplied to Clinton Power Station by United
Controls International, Stone Mountain, Georgia.
(iv) The purchase specification requires voltage control from the no
load condition to unit rating. Contrary to this requirement,
IP has found that the transformer is not stable in the no load
condition and trips when lightly loaded under various plant
conditions. A trip of the transformer upon addition of a
safety load could cause the loss of power to all the loads fed
by that transformer and result in the failure of safety related
equipment to perform intended safety functions.
(v) The repeated tripping of the regulated power transformer was
identified and determined potentially reportable under the
provisions of 10CFR21 on January 7, 1997.
(vi) Clinton Power Station (CPS) has 4 of the potentially affected
transformers installed in the Division 2 electrical system
under Plant Modification AP-028. Only one of the four units
has experienced tripping problems.
(vii) IP is disconnecting the four potentially affected transformers
from the Division 2 electrical system to remove them from
service in accordance with Plant Modification AP-032. IP and
representatives of United Controls are working on a network of
filters/surge suppressors and minimum load resistors to
eliminate the tripping problem.
(viii) IP has no advice about this issue for other purchasers or
licensees.
U-602704
Page 3
Additional information about this issue may be obtained by
contacting A. B. Haumann, Engineering Projects, at (217) 935-8881,
extension 4078.
Sincerely yours,
Wilfred Connell
Vice President
RSF/krk
cc: NRC Clinton Licensing Project
Manager NRC Resident Office, V-690
Regional Administrator, Region III, USNRC
Illinois Department of Nuclear Safety
INPO Records Center
United Controls International
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