HTGR
Reactor
By Lewis Lommers and Farshid
Shahrokhi, AREVA Inc.; Chris Hamilton
and Matt Richards, Ultra Safe Nuclear;
Scott Penfold, Technology Insights;
John Mahoney, High Expectations
International, LLC.
Lewis Lommers
Lewis Lommers leads High Temperature
Gas-Cooled Reactor engineering at
AREVA Inc.
He has over 25 years of experience
working on
HTGRs in various
areas including
system design,
transient analysis,
performance
optimization, and
overall concept
development. His
experience covers
several High
Temperature Gas-
Cooled Reactor
(HTGR) concepts
including the
Modular High
Temperature Gas-
cooled Reactor
(MHTGR), Gas Turbine Modular
Helium Reactor (GT-MHR), ANTARES
(an indirect cycle HTGR concept that
AREVA developed internally from about
2002 to 2007), and Next Generation
Nuclear Plant (NGNP).
He has a Bachelors degree in
Mechanical Engineering from the
University of Washington and a Masters
degree in Nuclear Engineering from
Purdue University.
Responses to questions by Newal
Agnihotri, Editor of Nuclear Plant
Journal. The responses are for the
HTGR concepts being promoted by the
NGNP Industry Alliance Limited and
its members. They are not necessarily
reflective of the opinions or positions of
the US Government’s NGNP Program.
1.
What is the cost in mills (1/10
of the US cent) per kilowatt hour for
producing electricity with a NGNP’s
HTGR reactor? Provide the following
breakdown: maintenance cost, operation
cost, and fuel costs.
Fixed O&M (w/o Fuel) –14 mill/
kWhr
Variable (Inc. Fuel) – 11 mill/kWhr
Total – 25 mill/kWhr
Note:
This does not include capital or
other project costs.
Costs are for an electric only plant.
For cogeneration applications, costs
will vary depending on specifics of the
application.
This is not an all-in production cost
or a means to compare technologies on
cost since capital in-
vestment and invest-
ment return has not
been described in
the responses.
The Alliance
has done extensive
economic analysis
to characterize the
arket and associ-
economics.
e have developed
n commercializa-
tion strategy and an
enterprise architec-
ture that identifies
capability and costs
associated with: a de-
velopment venture; a deployment project;
infrastructure framework; technology ex-
pansion that includes lesson learned, op-
erational experience (OE) and advanced
materials research and development; and
activities for program direction anticipat-
ed to support maturing technology appli-
cation, on-going economic analysis and
providing insight into additional markets
and opportunities. Estimated costs to
complete each of the Enterprise activities
are listed in the updated business plan.
2.
What improvements have been made
to the instruments within the Reactor
Pressure Vessel (RPV) as compared to
current reactor technology for measuring
pressure, temperature and other
parameters?
Significant improvements in instru-
mentation technology are not required
for the Steam Cycle High Temperature
Gas-cooled Reactor (SC-HTGR) design.
We have eliminated the requirements for
extensive incore instrumentation. The
primary thermal measurements are limit-
ed to inlet and outlet coolant temperature
and the coolant flow rate. Neutron de-
tectors for the reactor protection system
are located outside the reactor pressure
vessel (RPV). A traversing flux monitor
is used periodically to measure the axial
power profile.
3.
What diagnostic mechanisms have
been built in to monitor the degradation
of material, cables, equipment and
instruments within the RPV?
The SC-HTGR has ceramic core.
There are no cables in the core. The
metallic components in the reactor
pressure vessel are located in areas that
are only exposed to the cool core inlet
temperature and are designed to retain
their mechanical properties for the life of
the component.
4.
What prototype testing has been done
to validate the design to protect problems
during construction and operation of the
NGNP’s HTGR reactors?
All key equipment, including the
reactor core, the helium circulators,
the steam generators, and the vessels
are based on technology which has
been proven either in previous HTGR
projects or other industrial applications.
During final design and pre-fabrication
development, mockups will be used as
appropriate to confirm configuration
and fabrication approach. Confirmation
testing of components or component
modules will be performed as necessary
prior to installation.
5.
Who will be responsible for refueling
the reactor? Will it be the nuclear power
utility or the manufacturer?
Refueling will be performed by the
utility personnel. SC-HTGR refueling
is accomplished with remote mechanical
refueling machines based on the concept
proven successful at Fort St. Vrain.
Specific fuel movements are controlled
by the automated system according to a
preplanned sequence developed prior to
each refueling campaign. All movements
ar
the refueling control
st
vements are recorded
a
nfirm the accuracy of
the refueling operation.
28
NuclearPlantJournal.com Nuclear Plant Journal, May-June 2014
