[tinwhiskers] Whisker Incidents in the Nuclear Power Industry
- From: "Bob Landman" <rlandman@xxxxxxxxxxxxxxxxx>
- To: "tinwhiskers@xxxxxxxxxxxxx" <tinwhiskers@xxxxxxxxxxxxx>
- Date: Thu, 13 Mar 2008 21:53:23 -0400
Whisker Incidents in the Nuclear Power Industry
===================================
I asked Jay Brusse at NASA GSFC about his references for the 5 or more
whisker-related events that have impacted the nuclear power industry beyond the
notable Dominion Millstone plant trip in Connecticut back in 2005 (tin whiskers
on diode leads).
He shared his references below, but he told me he wanted to make a few points
first:
1) I have no way of knowing how comprehensive this listing is.
There could be other events unknown to me. For sure ZINC AND CADMIUM WHISKERS
are a threat that is worthy of consideration. There are apt to be multiple and
extensive uses of these materials in and around electronics.
2) The 2006 EU RoHS and subsequent RoHS-like legislations in no way played a
direct role in the events described herein. The manufacturers of these
sometimes 20+ year old systems made use of high purity tin coated items long
before RoHS was even a pipe dream in a legislator's eye. If one's objective is
to show politicians how metal whisker problems were experienced BECAUSE OF RoHS
COMPLIANCE GOALS, then a case such as the SWATCH [watch] Group from 2006 is a
better example. Their switch to Sn99.5Cu0.5 coatings on the package that houses
the crystals used in time pieces caused them much grief from tin whiskers. They
claim 5% of product failed from electrical shorts attributed to tin whiskers
from the SnCu material. They further claimed 30% of the product had evidence of
whiskers though not yet failing.
3) Nuclear power industry is by no means the only industry that has been
affected by metal whisker induced harm. As you know, many others including the
DoD, aerospace, automotive, medical, et al have been affected by metal
whiskers. When trying to convince customers, management, et al that metal
whiskers can produce harm, I often hear of organizations leveraging off of the
"failures/anecdotes" listed on the NASA whisker www site RATHER THAN using
THEIR OWN FIELD FAILURE EXPERIENCES. Sometimes this is because the experiences
were old and the people new. Other times it's because of fear of retribution
from exposing skeletons. Good luck trying to convince them to outline their own
experiences for public scrutiny.
And now, if you've made it this far in reading my note, you are to be rewarded
with my list of whisker references affecting the electric power industry.
In 2007, the NRC published the following white paper in which they cite 6
separate plant trips attributed to metal whiskers
http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr0933/sec3/2
<http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr0933/sec3/200.html
Summarizing those events, we see the following:
Date Nuclear Facility Location Event
=============================================
1987 Dresden Nuclear IL, USA Trip of "B" Channel of RPS
1990 Duane Arnold IA, USA Reactor Scram
1995 Duane Arnold IA, USA Reactor Scram signals produced during a controlled
shutdown
1997 Dresden Nuclear IL, USA Reactor Scram
1999 South Texas Project TX, USA Reactor Pre-Trip Alarm
2005 Dominion Millstone CT, USA Reactor Trip
I can add a few more to the above list which were not specifically covered in
the above NRC reference. Some of these are events affecting non-US based
facilities which do not fall under the purview of NRC
Date Location Source Event
=============================================
1995 Unknown Anonymous Tin Whiskers in Electromagnetic Relays
1999 Foreign Power Plant Foxboro Three (3) False Alarms --> Plant Shutdown
*
http://nepp.nasa.gov/whisker/reference/tech_papers/stevens2001-relay-failures-induced-by-tin-whiskers.pdf
*
http://www.nrc.gov/reading-rm/doc-collections/event-status/part21/1999/1
<http://www.nrc.gov/reading-rm/doc-collections/event-status/part21/1999/1999352.html
2000 Unknown GE Power Mgmt Unknown
- May not be directly used in power plants?
* http://www.geindustrial.com/pm/support/dls/dlssb01.pdf
2001 Foreign Nuclear Plant Anecdote Reactor Trip
* http://nepp.nasa.gov/whisker/anecdote/20year
<http://nepp.nasa.gov/whisker/anecdote/20year>
2002 Unknown Westinghouse Power Supply
Failures
*
<http://nepp.nasa.gov/whisker/reference/tech_papers/2002-westinghouse-tb02005.pdf
2006 Unknown Anonymous Zinc whiskers in Electromagnetic Relays
2006 Unknown Anonymous Tin Whiskers in Electromagnetic Relays
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