Part 21 Report - 1995-045
ACCESSION #: 9501310429
Nutherm
INTERNATIONAL,INC.
501 SOUTH ELEVENTH STREET/MT. VERNON, ILLINOIS 62864/(618) 244-6000/FAX
(618) 244-6641
January 23, 1995 QA-1-95-1006
US Regulatory Commission
Washington, DC
20555
Attention: Document Control Desk
Subject: 10 CFR Part 21 Report On Potential Defective Capacitors
Installed in Safety Grade Electrical Inverters
The following information is provided pursuant to the requirements of
10 CFR Part 21 to report a potential safety concern as communicated by
Fran Starr of Nutherm International, Inc. to Mr. Bill Huffman, of the
Nuclear Regulatory Commission by telephone on 1/20/95. This issue
concerns the potential for the failure of 3300 MFD) capacitors (P.N.
0133235) installed in HDR Power Systems Inverters.
Nutherm was notified by Tennessee Valley Authority (TVA) on 10/21/94 and
a copy of HDR Service Bulletin, Rev. 1.1, dated 2/19/92 (Attachment 1)
was faxed by TVA to Nutherm on 10/21/94. The defective capacitors, which
were manufactured by Mepco/Centralab) between the 30th week of 1986 and
the 50th week of 1988, exhibit low or no capacitance when failed. The
most common failure caused by one of these capacitors being faulty is
blowing one of the DC input fuses (FU1, FU2); thereby, rendering the HDR
Inverter from performing its design function.
The HDR Inverters that may contain the defective capacitors were
qualified and supplied by Nutherm to TVA and Bechtel Power Corporation as
follows, however, the installation/system location is unknown.
(1) TVA - Browns Ferry Nuclear Plant, Purchase Order No: 87NLF839263,
Item No: 1, Quantity two (2), 3KVA Inverters, Nutherm Reference No:
TVA-2649
(2) Bechtel Power - Northeast Utilities Connecticut Yankee Power
Station, Purchase Order No: 18691-E-954, Item 2.1, Quantity two (2),
5KVA Inverters, Nutherm Reference No: BPC-2552
Nutherm's corrective action included a request to TVA and Bechtel/
Northeast Utilities to perform a visual inspection and contact. Nutherm
with the results in order to determine if defective capacitors were
installed in the HDR Inverters (Attachment 2).
US NRC QA-1-95-1006
Attn Document Control Desk
1/23//95
Page 2 of 2
Nutherm recommended that TVA and Northeast Utilities inspect the
installed capacitors and if the inspection disclosed the capacitors to be
suspect, replace the suspect capacitors in order to assure that they do
not affect the facility to which they were supplied.
Should you have any questions regarding this matter, please contact me at
(618) 244-6000.
Sincerely,
NUTHERM INTERNATIONAL, INC.
Fran Starr
Manager
Quality Assurance
Attachments: Attachment 1
Attachment 2
cc: TVA Nuclear Power
Nuclear Licensing & Regulatory Affairs
Attn: Mgr. Technical Licensing Services
LP 5N 156B
1101 Market Street
Chattanooga, TN 37402-2801
Northeast Utilities
Connecticut Yankee Power Station
Attn: Licensing Dept.
362 Injun Hollow Road
East Hampton, CT 06424-3093
TVA - Browns Ferry Nuclear Station
Attn: C. Dyar, Procurement Dept.
P.O. Box 2000
Decatur, AL 35602-2000
Bechtel Power Corp.
Attn: V. R. Marathe, Elec. Eng. Chief
9801 Washingtonian
Gaithersburg, MD 20878-5356
W. Eckert
L. Hinson
HDR Uninterruptible
Power Systems
BULLETIN # 009
REVISION # 1.1
PAGE # 1
REV. DATE: 2/19/92
SERVICE BULLETIN
DATE: JANUARY 11, 1991 GENERATED BY: FIELD SERVICE APPROVED BY: DON
IMLAY
SUBJECT: DC CAPACITOR BANK
MODELS AFFECTED: ALL HIGH DC UNITS (MFR'D BETWEEN JUNE 1986 AND JUNE
1989)
IMPLEMENTATION DATE: DECEMBER 27, 1990
IMPLEMENTATION LEVEL: AS NECESSARY
DC capacitors manufactured by Mepco/Centralab (3300 MFD 350V, P.N.
0133235) between the 30th week of 1986, and the 50th week of 1988, have
been showing a defect that results in low or no capacitance when failed.
They may or may not leak.
These gray jacketed caps display the date code on the last line of
markings on the cap. (Ex: 8646 - 46th week of 1986). To check for low
capacitance, note the time it takes for the bleeder resistors to
discharge the cap bank after the precharge button is released.
Contact the factory for assistance if the DC cap bank contains the above
mentioned capacitors. HDR's phone number is: 614-771-5500 or fax number:
614-771-7219.
DISTRIBUTION: MANUFACTURING, FINAL TEST FIELD SERVICE. 3RD PARTY
SERVICE CO.
ATTACHMENT 1 QA-1-95-1006
Page 1 of 1
Nutherm
INTERNATIONAL. INC
501 SOUTH ELEVENTH STREET/MT VERNON, ILLINOIS 62864/(618) 244-6000/FAX
(616) 244-6641
November 7, 1994
Tennessee Valley Authority
Browns Ferry Nuclear Station
P.O. Box 2000
Decatur, AL 35602-2000
Attention: Ms. Claudia Dyar
Subject: Capacitors Installed in HDR Converters
Dear Ms Dyar:
Nutherm is in the process of investigating the aforemention subject. In
the interim the following is in regard to the question about the
capacitors in the 3KVA inverters purchased under your P.O. No.
87NLF839263. HDR's service Bulletin No. 009 addresses 3300 MFD capacitors
(P. N. 0133235) which are present in your units (circuit designation C1,
C5).
A visual inspection needs to be made to determine if the units contain
these capacitors with date codes between 8630 and 8850. The date codes
are located on the last line of markings on the capacitors. Other signs
to look for are bulging sides on the caps or leakage from the weep holes.
If the capacitors are suspect, a test can be performed to check for low
capacitance. Depress and release the precharge button and note the time
it takes for the bleeder resistors to discharge the cap bank after the
button is released. The voltage should bleed off slowly. If a rapid
decrease in voltage is noted the capacitors should be replaced.
The most common failure caused by one of these capacitors being faulty is
blowing one of the DC input fuses (FU1, FU2).
After your completion of the inspection please contact Nutherm with the
results. If you have any further questions please do not hesitate to call
me at (618) 244-6000.
Sincerely,
NUTHERM INTERNATIONAL, INC.
Lawrence Patterson
Director of Compliance
LP/kh
FL:C:\TVA
ATTACHMENT 2 QA-1-95-1006
Page 1 of 3
NUTHERM
INTERNATIONAL, INC.
501 SOUTH ELEVENTH STREET/MT. VERNON,ILLINOIS 62864/(618) 244-
6000/FAX(618) 244-6641
November 10, 1994 QA-11-94-985
Bechtel Power Corporation
9801 Washingtonian Boulevard
Gaithersburg, MD 20878-5356
Attention: V. R. Marathe, Electrical Control System Engineering
Chief
Subject: Capacitors Installed In HDR Converters
Dear Mr. Marathe:
Nutherm is in the process of investigating the aforementioned subject.
In the interim the following is in regard to the question about the
the capacitors in the 5KVA inverters purchased under your P. O. No.
18691-E-554. HDR's Service Bulletin No. 009, Rev. 1.1, dated 2/19/92
addresses 3300 MFD capacitors; (P.N. 0133235) which may be present in
your units.
A visual inspection needs to be made to determine if the units contain
these capacitors with date codes between 8630 and 8850. The date codes
are located on the last line of markings on the capacitors. Other signs
to look for are bulging sides on the caps of leakage from the weep holes.
If the capacitors are suspect, a test can be performed to check for low
capacitance. Depress and release the precharge button and note the time
it takes for the bleeder resistors to discharge the cap bank after the
button is released. The voltage is noted, the capacitors should be
replaced.
The most common failure caused by one of these capacitors being faulty is
blowing one of the DC input fuses (FU1, FU2).
Page 1 of 2
ATTACHMENT 2
Page 2 of 3
Bechtel Power Corporation
Attn: V. R. Marathe
QA-11-94-985
Page 2 of 2
After your completion of the inspection, please contact Nutherm with
results. if you have any further questions please contact, me at (618)
244-6000.
Sincerely,
NUTHERM INTERNATIONAL, INC.
Fran Starr
Manager
Quality Assurance
cc: Connecticut Yankee Power Station
Northeast Utilities
Attn: QA Mgr.
362 Injun Hollow Road
East Hampton, CT 06424-3093
BPC-2552 QA File
BPC-2552 Job File
FS: fs
ATTACHMENT 2 QA-1-95-1006
Page 3 of 3
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