Proven
Technology
SMR
By Jeff Benjamin, Westinghouse Electric
Company.
Jeff Benjamin
Jeff Benjamin brings more than 25
years of management experience in
the nuclear industry
to his position
as senior vice
president, Nuclear
Power Plants. In
this position, he
leads Westinghouse
efforts to meet
existing new-plant
customer needs and
to develop new-plant
opportunities.
Mr. Benjamin
played a key role
in the formation of
Exelon Corporation,
where he served
as vice president
of Licensing &
Regulatory Affairs from 2000 to 2007.
Mr. Benjamin earned a bachelor’s
degree and completed coursework for
a master’s degree (thesis pending) in
Nuclear Engineering from Oregon
State University. He also completed
the Advanced Management Program at
Harvard Business School in 2001.
Responses to questions by Newal
Agnihotri, Editor of Nuclear Plant
Journal.
1. What improvements have been made
to the instruments within the Reactor
Pressure Vessel (RPV) as compared to
generation III+ reactors for measuring
pressure, temperature and other
parameters?
The chosen Westinghouse SMR
instrument technology is similar to
Generation III+ technology.
2. What prototype testing has been
done to validate the design to protect
against problems during construction
and operation of the Westinghouse SMR
reactors?
To date, prototype testing has been
accomplished on qualification of the
CRDM latch magnets and on the Rod Po-
sition Indicators. A
long-term hydraulic
test has been con-
ducted on the SMR
fuel assemblies to
investigate the grid-
to-rod fretting of the
preliminary design.
Two full-scale test
SMR fuel assem-
blies were fabri-
cated and tested in
the Vibration Inves-
tigation & Pressure
drop Experimental
Research (VIPER)
test loop at the
Westinghouse Fuel
Plant in Columbia,
South Carolina. The results from this
testing show that the preliminary fuel
assembly design has very good fretting
wear performance.
As with all of our products,
Westinghouse will thoroughly test the
design and functionality of the SMR prior
to construction and operation.
3. Who will be responsible for refueling
the reactor? Will it be the nuclear power
utility or the manufacturer?
The utility is responsible for
refueling.Westinghouse is able to perform
this activity as a service for the utility if
requested. Westinghouse is providing
the refueling design and providing the
refueling equipment.
4. What are the plans to repair possible
problems within the pressurizer, and
other equipment and instruments within
the RPV?
The pressurizer is removed from the
containment with the steam generator
when refueling. If necessary, it can be
separated from the SG and maintained
separately in the Maintenance Hall. If
necessary, the pressurizer, due to its
small size, could be replaced as a single
unit if desired by the plant utility owner.
Maintenance on pressurizer heaters is
easier than current plants due primarily
to size and access affordability offered
when the pressurizer and steam generator
are removed during refueling. Pressure
and differential pressure transmitters are
located outside containment, affording
a much more suitable environment and
providing direct access for maintenance
and testing.
5. How long can the reactor keep
operating without:
Off-site power supply?
Loss of offsite power results in a
100% to 10% load rejection. The turbine
generator continues to provide power to
plant AC systems, including the reactor
coolant pumps. The reactor will remain
operating indefinitely.
Cooling water supply?
The loss of cooling water results in
the loss of the condenser vacuum and a
turbine trip. Power to the plant electrical
busses is provided by offsite power. This
is a 100% to 0% load rejection. The
reactor does not trip and can continue
to operate indefinitely below the power
range, if desired.
6. Are there provisions to bring external
portable connections for ensuring water
supply and electric connection for
cooling in case of a Beyond Design Basis
Event?
The plant coping period for Station
Blackout or Loss of Cooling Water is
at least seven days. There is sufficient
water inventory available to remove
residual heat for a minimum of seven
days without the need for AC or DC
power sources. Multiple connections are
available to add inventory to indefinitely
cool the plant. By design, a minimal
flow rate is required to make up for the
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NuclearPlantJournal.com Nuclear Plant Journal, March-April 2014
