Page 29 - Nuclear Plant Journal - March April 2013
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Nuclear Plant Journal, March-April 2013
29
8.
What post-Fukushima upgrades
have been made to the AP1000 plant in
response to U.S. NRC’s Near Term Task
Force Recommendations?
So far the NRC has formally
processed only a few of the near-term task
force recommendations, and has issued
orders to plants to enhance areas such
as spent fuel pool level monitoring. The
existing AP1000 plant’s design already
included all of the required features of the
upgrades and no incremental changes to
AP1000 plant were required.
Westinghouse
performed
an
assessment of the AP1000 plant’s design
for the Fukushima event and found that
the AP1000 plant would have had no core
damage and no radioactivity releases to
the environment.
It is possible that as the NRC
completes its assessment of the remaining
task force recommendations, some minor
design changes might be required. The
AP1000 plant’s Passive Safety Features
and the design that does not rely on ac
power will minimize any need for future
changes to the design.
9.
What fuel design, fuel monitoring,
and fuel storage enhancements have been
made in the AP1000 plant’s design?
The AP1000 plant’s design uses
standard Westinghouse 17X17 Robust
Fuel Assembly (RFA) fuel which is 14
feet long. It is very similar to the fuel
that Westinghouse is currently providing
to our fuel customers, with the exception
that most of the currently supplied fuel is
12 feet long.
There are advancements in the area
of tungsten gray rods and enhancements
in the capability to load follow without
changing the boron concentration in the
coolant.
10.
How have the penetrations to the
reactor pressure vessel been modified to
make them withstand higher temperature,
pressure, and harsh environmental
conditions, in case of a beyond design
basis accident?
The AP1000 plant uses in-vessel
retention (IVR), which includes flooding
the exterior of the reactor vessel to retain
a damaged core in the reactor vessel;
therefore, no modifications are required.
11.
What provisions have been made in
theAP1000 plant to exclude the possibility
of hydrogen explosions similar to 3 Mile
Island and Fukushima Daiichi?
The AP1000 plant uses two passive
autocatalytic
recombiners
(PARs)
and 62 battery powered igniters that
burn hydrogen mixtures prior to the
concentration of hydrogen reaching
the explosive range. These devices are
intended to eliminate the possibility of a
hydrogen explosion in the containment
during severe accidents.
AP1000 is a trademark or registered
trademark of Westinghouse Electric
Company LLC, its affiliates and/or its
subsidiaries in the United States of
America and may be registered in other
countries throughout the world. All
rights reserved. Unauthorized use is
strictly prohibited. Other names may be
trademarks of their respective owners.
Contact: Ed Cummins, Westinghouse
Electric Company, 1000 Westinghouse
Drive,CranberryTownship,Pennsylvania;
telephone: (412) 374-6211, email:
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