fIMSWS
TMI: New generator a delicate process
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the reactor building and placed
in the used fuel pool. The outside
air will be pulled into the reactor
building so that the air inside does
not go out. Once the generators
are replaced, the opening in the
reactor building will be restored
to its original design configuration
and the reactor building will be
pressure tested prior to start-up
of the plant,” according to the
Fall 2009 community update.
The installation of the steam
generators was contracted to The
Steam Generator Team, LLC,
which has successfully completed
14 similar steam generator
replacement projects. To install
the steam generators, an opening
will be created in the containment
building wall to remove the old
steam generators and install the
new steam generators, according
to the Three Mile Island Steam
Generator Replacementfact sheet.
”1 don’t worry about the
installation,” said Richard
Ciocci, Associate Professor
of Mechanical Engineering at
Penn State Harrisburg, “I would
say the steam generator portion
worries me less than other parts
of the process.”
Within the next five years,
the license for Unit 1 on TMI
will expire on April 19, 2014
according to the Applicant’s
Environmental Report License
Renewal Operating Stage, part of
the license renewal process.
The replacement of the steam
generators ensures another 20
years of service. According to
Noll in the Fall 2009 community
update, “In January 2008 we
submitted an application to
the U.S. Nuclear Regulatory
Commission (NRC) to extend
our operating license for 20
years. We are nearing the end of
that process and if the application
is approved TMI will be able to
operate until 2034,” he said.
“Three Mile Island (TMI)
Unit 1 located in Londonderry
Township, Dauphin County, in
Pennsylvania, generates 852
megawatts of clean, safe and
reliable electricity for more than
800,000 homes,” according to
TMl’s Web Site.
For more information about
Three mile Island and the steam
generator replacement visit:
http://www.threemileislandinfo.
com/
What is a Steam Generator?
Steam generators are heat
exchangers used in Pressurized Water
Reactors (PWR) like Three Mile Island
Unit 1.
Steam generators act like giant dou
) ble bailers. Pressurized hot water from
I the reactor enters the steam generator,
1 passing through thousands of small
1 tubes, similar to hot water passing
| through a car radiator. The heat from
i inside of the tubes is transferred to a
j second supply of water outside the
s
5
tubes, which
flashes into steam.
The steam is then
sent through large
pipes to spin the
turbines and gen
erator. The two
supplies of water
inside and outside
of the steam gen
erator tubes never
mix.
Three Mile Island