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Home NRC Library Document Collections Events, Reports Associated with Part 21 Reports 1996

Part 21 Report - 1996-580

 
 
ACCESSION #:  9610010294

Rosemount Nuclear Instruments      Rosemount Nuclear Instruments, Inc.
                                   12001 Technology Drive
                                   Eden Prairie, MN 55344 USA
                                   Tel 1 (612) 828-8252
September 20, 1996                 Fax 1 (612) 828-8280

Re:  Notification under 10 CFR Part 21 for Model 353C and 353C1 Conduit
     Seals

Pursuant to 10CFR Part 21 Paragraph 21.21 (b), Rosemount Nuclear
Instruments, Inc. (RNII) is writing to inform you of a potential
nonconformance related to certain model 353C and 353C1 nuclear qualified
conduit seals.  (Model 353C and 353C1 are identical in construction
except for the leadwire length).  The nonconformance was the failure of
RNII standard manufacturing acceptance tests to identify production units
containing a short condition.

Model 353C Conduit Seals are designed to supply an absolute barrier
between the electrical connections of a pressure transmitter and the
external environment typical of nuclear power plants.  Model 353C and
353C1 Conduit Seals incorporate a glass-to-metal feed through header
assembly used to separate the transmitter and the external environment.
Two 22 gage insulated shielded leadwires are used and terminate at both
sides of the header assembly.  A conduit case is used to hold the header
and is filled with epoxy to maintain the separation of the leadwires.

RNII has become aware of two model 353C conduit seals received by a user
in an output short condition.  The units were not installed in a plant
process but exhibited the short condition during functional tests at the
users location prior to installation.  The two units were returned to
RNII for root cause failure analysis.  The failure analysis confirmed the
short condition and determined the short was caused by contact between
the outlet end leadwires internal to the conduit case.  Because the
outlet end leadwires are encased in epoxy we concluded that contact
between the leadwires occurred during manufacturing processes.

RNII completes two standard functional tests on 100% of model 353C and
353C1 production units.  The tests measure continuity of the leadwires,
and insulation resistance between each leadwire and between each leadwire
to the conduit case.  Any unit exhibiting a short condition would be
identified by these tests.

RNII concludes that the continuity test and the insulation resistance
test were either completed incorrectly or not completed for these two
units.

RNII is notifying users of 353C and 353C1 conduit seals of a potential
nonconformance in the acceptance testing completed on 100% of production
units.  If the conduit seal has successfully completed a functional test,
this notification is not applicable.

FISHER-ROSEMOUNT

10CFR21 Notification
20-Sept-96
Page 2 of 4

1.0  Name and address of the individual providing the information:

     Mr.  Mark Van Sloun
     Vice President & General Manager
     Rosemount Nuclear Instruments, Inc.
     12001 Technology Drive
     Eden Prairie, MN 55344

2.0  Identification of items supplied:

     Model 353C and 353C1 Conduit Seals

3.0  Identification of firm supplying the item:

     Rosemount Nuclear Instruments, Inc.
     12001 Technology Drive
     Eden Prairie, MN 55344

4.0  Nature of the failure and potential safety hazard:

     This notification relates to Model 353C and 353C1 conduit seals
     which exhibit a short condition.  Any model 353C and 353C1 conduit
     seal which does not indicate a short condition is deemed acceptable
     and this notification is not applicable to such units.  Also this
     notification is not applicable to units which have successfully
     completed a functional test.

     RNII does not have sufficient information to determine the safety
     impact related to plant applications.  Licensees must determine the
     impact on plant operations and plant safety and take action as
     deemed necessary.

10CFR21 Notification
20-Sept-96
Page 3 of 4

5.0  The corrective action which is taken, the name of the individual or
     organization responsible for that action and the length of time
     taken to complete that action:

     RNII has identified that the nonconformance was due to failure of
     manufacturing functional tests to identify model 353C and 353C1
     conduit seals in a short condition prior to shipment.

     RNII recommends that all users of 353C and 353C1 conduit seals
     complete an Insulation Resistance (IR) Test, or other equivalent
     test which will identify a short output condition, on all conduit
     seals which are not currently operational (e.g.  maintained in
     stores or as spare/replacements).  If an IR test will be used, the
     test should be completed between the two leadwires and from each
     leadwire to the conduit case.  Acceptance criteria is a minimum IR
     of 100 megohms at 100 V dc.

     If you locate a conduit seal in a short condition, please contact
     Tim Layer at (612) 828-8240.  The unit will be replaced at no
     charge.

     RNII internal corrective actions are summarized as follows:

     1.   Review Continuity Test and IR Test procedures for clarity.
          Complete refresher operator training.
     2.   Add an independent Quality Assurance Inspection step in the
          manufacturing process to re-test the IR of 100% of production
          units prior to release.

     The above actions will be completed within 60 days of this
     notification.

     No further action related to this issue is expected.  Mr.  Van Sloun
     is responsible should any further action related to this issue be
     necessary.

6.0  Any advice related to the potential failure of the item:

     This notification applies to 353C and 353C1 conduit seals which have
     not completed an acceptance test by the user.  Standard plant
     procedures for acceptance testing and installing RNII transmitter -
     conduit seals should be sufficient to identify this potential defect
     and no further action is recommended.

     The end user must determine the full scope of this nonconformance as
     it relates to plant operations and plant safety and take action as
     deemed necessary.

10CFR21 Notification
20-Sep-96
Page 4 of 4

Rosemount Nuclear Instruments, Inc.  has a strong commitment to the
nuclear industry and assures you that we are dedicated to the supply of
high quality products and services to our customers.  We are sorry for
any inconvenience.  If there are any questions, or you require additional
information related to this issue, please contact Tim Layer (612) 828-
8240, Jane Sandstrom or Ian Baldry (612) 828-8250.

Sincerely,

ROSEMOUNT NUCLEAR INSTRUMENTS, INC.

M.  L.  Van Sloun
Vice President & General Manager

MVS:TJL

*** END OF DOCUMENT ***

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