Mission
My research is inspired by the facts that the world population and the corresponding energy
consumption steadily increase. All these people striving for a better quality of life, will
double the energy consumption rate in only several decades from now.
Although science and technology have made it possible to extract energy from ever dense power
sources, from wood to coal to oil to gas to nuclear, we need to fully exploit all the energy
sources available to meet future energy demands. Therefore, the mission of my research and
that of the PNR research group
is to contribute to the development of safe and sustainable nuclear energy.
My research focuses on the following reactor types:
Very High Temperature Reactor (VHTR)
This reactor uses so-called TRISO particles that contain the fuel nuclides and fission products.
These particles can resist very high temperatures, up to 1600 oC.
For a well-designed reactor, and that's our job, there is no scenario in which the temperature
of the TRISO particles will exceed this limit.
If the temperature would increase too much, the fission chain reaction will stop and the remaining
decay heat of the radioactive fission products will safely be transfered to the environment.
Two reactor designs exist: one with a pebble-bed core and one with a prismatic core.
No big difference for a reactor physicist like me, but for the engineer each core design has
its own pros and cons. Simply said: the pebble-bed reactor can be fueled on-line, which is an
advantage for some applications, while the prismatic core can operate a long time without refuelling,
which is advantageous for other applications.
For both reactor designs, a test reactor is in operation either in China (pebble-bed) or Japan
(prismatic core). Both of them are cooled with helium.
My research focuses on methods to safely increase the outlet temperature of the helium coolant.
This may give to a better efficiency of the electricity generation process, and lead to possibly
new applications like nuclear hydrogen production via thermo-chemical water-splitting processes.
Furthermore, the High Temperature Reactor may be fueled with Thorium, which is abundantly present in the earth's crust
and which produces less hazardous long-lived nuclear waste.
Molten Salt Reactor (MSR)
In this reactor, the fuel is mixed with a molten lithium-berylium-fluroide salt.
Only when this salt enters the graphite core, the neutrons released in a fission event can moderate
to thermal energies and initiate new fission. Because the molten salt is used to remove the heat
from the core and to circulate the fuel, a fraction of it can be diverged to extract the
fission products and to add fresh fuel. Because of this on-line refuelling capability and the high
neutron efficiency, the MSR is the only reactor with a thermal neutron spectrum in which breeding
of new nuclear fuel can be achieved. Simply add thorium to the salt and you will get fissile uranium
for free.
My research focuses on Molten Salt Reactors to exploit the enormous
thorium resources available. If we succeed, we will have energy sufficient for tens of thousands of years!
Fast Reactors (GFR)
To extend the sustainability of nuclear energy, the introduction and exploitation of breeder reactors
seem inevitable. Breeding new fuel from abundantly available uranium and thorium reserves can extend the
nuclear energy option by tens of thousands of years. Although the Molten Salt Reactor mentioned above can be
used to breed new fuel from Th-232, the main focus in this area is on the use of fast reactors operating
with uranium and plutonium as a fuel.
My research focuses on the Gas-cooled Fast Reactor (GFR), which uses helium as a coolant and a ceramic
composition made of transuranics as a fuel. This reactor can be operated in self-breeding mode, which means
that it produces just enough fuel to sustain the fission chain reaction; in burner mode, which means it can
transmute the hazardous actinides from other reactors to relatively short-lived nuclides; or in breeding mode,
which means it can actually breed new fuel (produce more fuel than consumed). Current research focuses on the
neutronics analysis of GFR and sensitivity analysis to determine the uncertainties and parameters contributing
to these uncertainties in the GFR reactor core design.
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