[ RadSafe ] Re-starting San Onofre

Victor Anderson victor.anderson at frontier.com
Tue Mar 19 19:10:35 CDT 2013


Most interesting reading.  I read the Mitsubishi Heavy Industries Report.
Most interesting.  First, it is a good example of a root cause analysis
report(RCA).  My first comment is that at power there was whole lot of
rocken and roll' going on in those steam generators.  More than normal.
Some engineers have a whole lot of interesting work to do.  IMHO, the
engineering problem is how to keep those steam generator tubes from
excessively vibrating.  As I recall, U-tube steam generators have primary
coolant flowing in several thousand tubes in a U shape.  The top of the
tubes where the U-bend lies is the region where secondary steam exists.  Now
at full power, these tubes are carrying thermally hot water under pressure
with a heat energy of about 2,000 MW.  These tubes are subject to all kinds
of mechanical forces.  So, as a result, the engineering challenge is to keep
these tubes from wearing out due to vibration.  Knowing that the SOGS steam
generator design was not adequate ahead of time was not that easy.  After
reading the report, I think this was just a gotcha.  The real question is
how will the utility and MHI fix the problem.


-----Original Message-----
From: radsafe-bounces at health.phys.iit.edu
[mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of Sewell, Linda
Sent: Tuesday, March 19, 2013 4:08 PM
To: 'The International Radiation Protection (Health Physics) Mailing List'
Subject: Re: [ RadSafe ] Re-starting San Onofre

Hi All,

There is a great explanation (from the industries perspective) of the Steam
Generator issues on NEIs blog located here:

I think it does a really good job of explaining the issue.

Linda Sewell

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