United States Nuclear Regulatory Commission - Protecting People and the Environment

Morning Report for June 14, 2005

Headquarters Daily Report

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REGION III

Part 21 2005-0022 - A Potential for Premature Failure of Control Rod Instrumentation Power Supply

Licensee/Facility:

AMETEK SOLID STATE CONTROLS
AMETEK SOLID STATE CONTROLS
COLUMBUS, Ohio
Dockets:

License No:
Notification:

MR Number: H-2005-0015
Date: 06/10/2005


Reviewer: TABATABAI, OMID

Discussion:

Part 21 2005-0022 - A Potential for Premature Failure of Control Rod Instrumentation Power Supply

Ametek Solid State Controls produces AC-DC power supplies that are used at several nuclear power plants. Ametek states that its Series AC-DC power supplies may have a problem with premature failure. The specific Model Numbers affected are as follows:

85-RP1510-00
85-RP4804-00
85-RP4808-00
85-RP DUAL-4807\1

Ametek states that an intermittent loss of continuity in a magnet wire connector may cause overheating in a lug and transformer which could eventually result in a premature failure of the power supply (within approximately two years of initial service). The problem was discovered during testing of power supplies by Ametek. No nuclear power plants have reported any problems with the power supplies.

Ametek states that its records indicate that these power supplies were supplied to Braidwood, Byron, and DC Cook.

Ametek believes that the power supplies are used for control rod instrumentation. A total of 33 power supplies have been sold but Ametek believes that most of these are not in service. Ametek recommends that these power supplies either be returned to Ametek for rework or that the affected sites request service by an Ametek representative onsite.

Contacts:

Name Office Abbrev Phone No E-Mail
TABATABAI, OMID NRR (301) 415-6616 OTY@nrc.gov


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REGION IV

Part 21 2005-0015 - Thermo Electron Data Acquisition Recorders

Licensee/Facility:

THERMO ELECTRON CORPORATION
THERMO ELECTRON CORPORATION
HOUSTON, Texas
Dockets:

License No:
Notification:

MR Number: H-2005-0016
Date: 04/14/2005


Source Document: Call / Fax from Licensee

Reviewer: RINI, BRETT A

Discussion:

Part 21 2005-0015 - Thermo Electron Data Acquisition Recorders

This Morning Report is being issued due to a safety concern related to Thermo Electron data acquisition recorders. On April 7, 2005, Thermo Electron engineers determined that the nuclear safety-related series of paperless data acquisition recorders may exhibit failure to start up due to a deficiency in a power supply module (See EN 41599). The potentially affected recorders are SV10C, SV18C and SV28C series recorders.

Thermo Electron has determined that the cause of the anomaly is the rise time variation of the installed commercial power supply module. The module is a generic switching power supply used in a multitude of commercial applications. This module is mounted on a power supply carrier printed circuit assembly (PCA). According to Thermo Electron, this anomaly only occurs when a recorder has been turned off and then restarted. Should the recorder fail to boot up, the anomaly can be corrected by cycling power to the recorder until the recorder re-boots. Thermo Electron stated that this startup failure may occur on recorder units where the power supply carrier PCA contains a power supply module that does not have a "Made in USA" mark.

According to Thermo Electron, there have been no failures reported in any nuclear safety-related applications of SV10C, SV18C or SV28C recorders. Should the failure occur, it is detectable and will not cause the recorder to present or record any erroneous data. As a precaution, Thermo Electron is recommending the replacement of any affected PCA with a redesigned PCA for recorders which are used as the primary instrument for recording or reporting critical data and/or functions; are not backed up by an uninterruptible power supply (UPS) system; and contain the affected PCA. Affected PCA part numbers are CB100492, CB100505, CB100511 and CB100531. Thermo Electron engineers have redesigned the power supply carrier PCA to accommodate a wider variation in rise times.

Nuclear utilities that have purchased nuclear safety-related SV10C, SV18C or SV28C recorders that are potentially affected by this notification are: Watts Bar, Beaver Valley, McGuire, Browns Ferry, River Bend, and Brunswick.

During a telephone conversation with NRC staff on June 6, 2005, the vendor stated that no new issues have been discovered with these recorders since their report was submitted. The vendor also indicated that this issue mostly affected simulators since recorders may be rebooted between simulator training events. The vendor now has replacement power supplies available and is receiving replacement orders from utilities.

Thermo Electron issued ENs 40011 and 40609, and the NRC issued Morning Reports H-2003-0035 and H-2004-0010 regarding previous issues with Thermo Electron recorders. Information for these issues as well as other Part 21s is available at the NRC's Operating Experience web page at:
http://www.nrc.gov/reading-rm/doc-collections/event-status/part21/.

Accession Numbers:

Accession No Accession Date
ML051080315 04/14/2005

Contacts:

Name Office Abbrev Phone No E-Mail
RINI, BRETT A NRR (301) 415-3931 BAR3@nrc.gov
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