United States Nuclear Regulatory Commission - Protecting People and the Environment

ACCESSION #: 9502160190

                                              Nutherm
                                              INTERNATIONAL, INC.

          501 SOUTH ELEVENTH STREET/MT. VERNON, ILLINOIS 62864/
                    (618) 244-6000/FAX (618) 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 intrim 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-1-95-1003
  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
9901 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
capacitors in the 5KVA inverters purchased under your P.D. 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 an 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).

                               Page 1 of 2

                              ATTACHMENT 2                  QA-1-95-1003
                               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 the
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-1-95-1003
                               Page 3 of 3


                                              Nutherm
                                              INTERNATIONAL, INC.

          501 SOUTH ELEVENTH STREET/MT. VERNON, ILLINOIS 62864/
                    (618) 244-6000/FAX (618) 244-6641

                      PART 21 INITIAL NOTIFICATION          QA-1-95-1003

                            January 20, 1995

                               Page 1 of 2


I.    Fran Starr, Manager - Quality Assurance
      Nutherm International, Inc.
      501 South 11th. Street
      Mt. Vernon, IL 62864

II.   3300 MFD capacitors, P.N. 0133235, contained in 3KVA and 5KVA HDR
      Inverters supplied to Tennessee Valley Authority (TVA) Browns Ferry
      Nuclear Plant and Northeast Utilities Connecticut Yankee Power
      Station via Bechtel Power Corporation.  Installation/system
      locations are unknown.

III.  The 3300 MFD capacitors, P.N. 0133235, were manufactured by
      Mepco/Centralab and are contained in the HDR Inverters.  The
      Inverters were qualified and supplied by Nutherm International,
      Inc., 501 South 11th. Street, Mt. Vernon, IL

IV.   The defective capacitors, which were manufactured 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.

V.    Nutherm was notified by TVA on 10/21/94 and copy of HDR Service
      Bulletin, Rev. 1.1, dated 2/19/92 was faxed by TVA to Nutherm on
      10/21/94 (Attachment 1).

VI.   The HDR Inverters that may contain the defective capacitors were
      supplied by Nutherm to Tennessee Valley Authority (TVA) and Bechtel
      Power Corporation as follows:

      (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-554, Item 2.1, Quantity
           two (2), 5KVA Inverters, Nutherm Reference No: BPC-2552


                      PART 21 INITIAL NOTIFICATION          QA-1-95-1003

                            January 20, 1995

                               Page 2 of 2

VII.  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).

VIII. Nutherm recommended that TVA and Northeast Utilities inspect the
      installed capacitors and if the inspection disclosed the installed
      capacitors to be suspect, replace the suspect capacitors in order
      to assure that they do not affect the operation of the facility to
      which they were supplied.


                               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 grey 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-1-95-1003
                     Page 1 of 1


*** END OF DOCUMENT ***

Page Last Reviewed/Updated Thursday, March 29, 2012