2016 January1 Nuclear Options for the Future B. Rouben McMaster University EP4P03_6P03 Nuclear Power Plant Operation 2016 January-April

Table of Contents We look at possibilities for the operation of nuclear plants in the future January2

Current Power Reactors  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 January3

More Uranium?  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? 2016 January4

Fuel Reprocessing 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 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 January5

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 !  More thousands of years! 2016 January6

Thorium 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 January7

Possibilities for CANDU Existing CANDU reactors have been running on natural-uranium (NU) fuel. However, the neutron economy afforded by the heavy-water moderator, and the on-power- refuelling capability, give CANDU reactors a great deal of flexibility in running on a variety of other fuels January8

CANDU Advanced Fuel Cycles 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) – UO 2 + PuO 2 Use of Irradiated Fuel from LWRs, e.g., DUPIC cycle (Direct Use of LWR Fuel in CANDU) Minor-Actinide (Np, Am, Cm) burning 2016 January9

CANDU / PWR Synergism Spent Fuel Double the energy can be extracted from the spent fuel Higher concentration of fissile U + Pu in spent fuel 2016 January10

CANDU and PWR Fuel Natural Uranium 0.7% U-235 Spent NU CANDU Fuel 0.23% U % Pu f Enriched Uranium 3.5% U-235 Spent PWR Fuel 0.9% U % Pu f PWR CANDU 2016 January11

CANDU / PWR Synergism Spent PWR Fuel 0.9% U % Pu-fissile - MOX - 0.9% U Actinides Enriched Fuel 3.5% U-235 CANDU Dry Process PWR Reprocessing Plant 0.9% U % Pu DUPIC Fuel 2016 January12

CANDU ADVANCED FUEL CYCLES Increase resource utilization Provide energy for centuries Reduce quantity of spent fuel Reduce fuelling costs Reduce quantity of mined uranium Tailor reactivity coefficients Contribute to global peace & disarmament Reduce capital costs Synergistic with PWRs 2016 January13

Future What does the future hold for nuclear power? 2016 January14

2016 January15 END