United States Nuclear Regulatory Commission - Protecting People and the Environment

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

*** END OF DOCUMENT ***

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