Transcript 16_advanced_fuel_cycles

Nuclear Options for the Future
B. Rouben
McMaster University
EP4P03_6P03
Nuclear Power Plant Operation
2015 January-April
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Table of Contents
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We look at possibilities for the operation
of nuclear plants in the future.
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Current Power Reactors
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Most current reactors are “thermal” reactors, using the
fission of U-235 (U-238 contributes a very small
percentage of the fissions).
Current reserves of uranium can run the current fleet of
reactors for ~500 years*.
The cost of fuel is only a small percentage of the price
of electricity.
Will nuclear power end in a few hundred years?
* D.Lightfoot et al, “Nuclear Fission Energy is Inexhaustible”, Proceedings of the First Climate
Change Technology Conference, Montreal, QC, Engineering Institute of Canada, Ottawa, May
2006
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More Uranium?
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As uranium reserves decrease, the price of uranium
would increase from the current low price (~$100/kg)
This would spark more uranium exploration.
If mined-uranium reserves came to an end, uranium
could be extracted from seawater, enough uranium to
provide all the world’s energy for thousands of years
using thermal reactors.
What do we have, if anything, beyond U-235?
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Fuel Reprocessing
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U-238 gives only a small percentage of the
fissions in thermal reactors, but it contributes
importantly as a “fertile” nuclide by producing Pu.
The fissile fraction (U-235, Pu-239 + Pu-241) in
fuel removed from current reactors is ~50-65% of
the original U-235!
Irradiated fuel can be reprocessed to recover the
fissile fraction, which can be used in new fuel,
e.g., as mixed-oxide (MOX) fuel.
Expensive, but some countries already do this.
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Breeder Reactors
Fast breeder reactors use fast neutrons to
fission U-238 and produce more fuel than
they consume!
 U-238 is no longer just waste. Fast breeders
can multiply the effective uranium resource
by a factor of 50-120!
More thousands of years!
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Thorium
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Th-232 is also a fertile nuclide.
Similarly to U-238 producing Pu-239 by
neutron absorption followed by 2 beta
decays, Th-232 can produce the fissile
nuclide U-233!
Thorium is 3-4 times as abundant as
uranium, further increasing our resources.
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Possibilities for CANDU
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Existing CANDU reactors have been running
on natural-uranium (NU) fuel.
However, the neutron economy afforded by
the heavy-water moderator, and the on-powerrefuelling capability, give CANDU reactors a
great deal of flexibility in running on a variety
of other fuels.
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CANDU Advanced Fuel Cycles
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Slightly Enriched Uranium (SEU) – 0.9% to
1.2% enrichment. With 0.9% U-235, doubles
achievable fuel burnup
Recovered uranium (from irradiated fuel)
Plutonium dispositioning
Mixed-Oxide Fuel (MOX) – UO2 + PuO2
Use of Irradiated Fuel from LWRs, e.g.,
DUPIC cycle (Direct Use of LWR Fuel in
CANDU)
Minor-Actinide
(Np,
Am,
Cm)
burning
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CANDU / PWR Synergism
Double the
energy can
be extracted
from the
spent fuel
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Spent Fuel
Higher
concentration
of fissile U +
Pu
in spent fuel
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CANDU and PWR Fuel
Natural Uranium
Spent NU CANDU Fuel
0.7% U-235
0.23% U-235
0.27% Puf
CANDU
Enriched Uranium
Spent PWR Fuel
3.5% U-235
0.9% U-235
0.6% Puf
PWR
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CANDU / PWR Synergism
Reprocessing Plant
Enriched
Fuel
- MOX
- 0.9% U-235
- Actinides
Spent PWR
Fuel
3.5% U-235
0.9% U-235
0.6% Pu-fissile
PWR
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Dry Process
DUPIC
Fuel CANDU
0.9% U-235
0.6% Pu
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CANDU ADVANCED FUEL CYCLES
Reduce capital
costs
Increase resource
utilization
Contribute to
global peace &
disarmament
Reduce quantity of
mined uranium
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Provide energy for
centuries
Reduce quantity of
spent fuel
Reduce fuelling
costs
Tailor reactivity
coefficients
Synergistic with PWRs
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Future
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What does the future hold for nuclear
power?
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END
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