A Low Carbon Future The Nuclear Option Gregg Butler, Director IDM and Professor of Science in Sustainable Development, University of Manchester
Nuclear The Potential
Technologies Present and Future NOW Thermal Reactors mainly Light Water Reactors PWR/BWR Uranium fuel in (heat/electricity) and spent fuel out Other types Magnox, AGR, PHWR etc are similar.......
Technologies Present and Future Thermal reactors essentially burn the 0.7% U235 isotope in the natural uranium PWRs actually burn about 0.6% of U as mined the rest is left as tails from enrichment or remains as uranium and plutonium in the spent fuel PWRs use around 200teU as mined per Gw(e) year generated Current (+ presumed) world uranium resources can give 27,000 (65,000)GWy = 15 (37)% of current world electricity consumption for 100 years
UF6 Tails Storage UF6 UO2 Once-through cycle UF6 Tails Enrichment LEU UF6 UO2 Fuel Fab n Purification Natural U Mining & Milling UO3 UF6 0.6% PWRs Spent Fuel Storage 99.4% Transport ILW Disposal LLW Disposal Spent Fuel Disposal
Technologies Present and Future Future fast reactors and thorium-burners Essentially burn U238 and/or thorium can burn virtually all uranium (or thorium) as mined Use around 2-4teU as mined per Gwy (~x50 compared to thermal) Current (+ presumed) world uranium resources can give (at 4teU per Gwy) 1.35M (3.25M)GWy = 100% of current world electricity consumption for 750 (1850) years plus potentially more than this from thorium BUT requires reprocessing and recycling of 4/5/05 plutonium (or U233 for thorium burning)
UF6 Tails Storage Fast Reactor UF6 UO2 Fast Reactor cycle UF6 Tails Enrichment LEU UF6 UO2 Fuel Fab n Purification Natural U Mining & Milling PuO2 Secure Storage Pu Fuel Fabrication UO3 UF6 Rep-UO3 ILW ILW Disposal Reprocessing HLW Vitrification LLW LLW Disposal PWRs Spent Fuel Storage Transport Spent Fuel Disposal
UK reactor experience is NOT typical!
Reactors in the UK Experience to date Generation I Magnox: 10 stations 9 different designs (plus another two exported!) Comment: Gas cooled, graphite moderated, low power density therefore big and high capital costs used the technology we had, not the technology that would be most economic No standardisation, limited learning curves a boffin s charter
Reactors in the UK Experience to date Generation 2a AGR: 7 stations 4 designs, 3 design and construction consortia Comment: 18 reactors, 14 designs Only the near-identical Heysham 2 and Torness stations were built in parallel, and this proved very beneficial in minimising delays and improving construction efficiency Optimised on thermal efficiency and low enrichment needs (technologies we had... ) still big, expensive, near-prototypes. The wonder is not that they ve had problems but that they are still operating!
Reactors in the UK Experience to date Generation 2b PWR: 1 station, derived from US design but extensively modified ends as very much a one of a kind Comment: Take someone else s optimised technology, and have the regulators redesign it But at least it started out as what the rest of the world was using!!
Reactors in the UK Experience to date Obvious that another Sizewell B would mean no new reactors in the UK, ever BUT since 2007 the Generic Design Assessment (NII + EA + DfT + OCNS) have concentrated on assessing rather than redesigning, and appear to be successfully addressing real safety issues This improvement should be locked in by combining nuclear regulation under a new Office of Nuclear Regulation Proposals for >10GWe from 3 consortia Effects of new Government?? Nuclear but no subsidy and no loan to Sheffield Forgemasters UK business? Timescales?
Nuclear Pros and Cons
Nuclear Pros and Cons PRO it s low carbon Median estimates of 7-22 gco2/kwh lower as enrichment technology evolves but higher as ore grade reduces c/f 385 g/kwh for gas and 755 g/kwh for coal e.g. Sizewell B saves a minimum of 3.275 million tonnes of CO2 per annum But: there has been one study giving much higher numbers (90-140 g/kwh) and this mainstream + outlier is a recurring theme in nuclear assessments.
Nuclear Pros and Cons PRO environmental and health detriments are low Total fuel cycle world 500-year collective dose of ~235 man Sv per GWy with health detriment valuations in the 300-400K range breaks even at around 0.12/teCO2 But: there is no universally accepted valuation methodology with cases to be made for the detriment being near zero, but with the Low Level Radiation Campaign suggesting x300 on radiation risk and infinite time integration giving ~x8
Nuclear Pros and Cons PRO provides secure and reliable baseload power at reasonable cost Overall world LWR experience is improving and >85% load factor now commonplace Power cost little dependent on fuel cost x2 on U price gives x1.022 on electricity can afford to stockpile fuel Evidence that capital costs have risen hopes that series production will give reductions But: UK s experience is NOT typical and an object lesson in how NOT to do things
Nuclear Pros and Cons Con spend on nuclear will discourage spend on better low carbon options Hard facts/models difficult to come by, and not helped by uncertain relationship between Government policy and market responses Complicated by grid/demand relationship nuclear baseload, intermittent renewables But: do we have the choice? Are we really likely to meet an 80% CO2 reduction target even if every possible method is used let alone if we start being picky?
Nuclear Pros and Cons Proliferation concerns Spread of nuclear power increases likelihood of theft and proliferation? BUT method of choice is centrifuge enrichment under the hill Iran, Pakistan, etc no-one has proliferated from LWRs and fast reactor Pu would be a real challenge for bomb-making Proliferation-resistant fuel cycles could be designed BUT could easily be too technologically challenging and expensive to be practical
In conclusion..... I ve been in this industry since the dawn of time and I ve been busily looking in cupboards and turning over stones for well over a decade I ve seen nothing in the cupboards or under the stones that says nuclear can t make a safe, worthwhile contribution to security of supply and carbon reduction provided only that regulation is proportionate and the UK strikes reasonable commercial deals with those that now own us!
In conclusion..... If Global Warming is a serious as we think it is, Homo Sapiens seems to be facing a very big problem akin to baling out the Titanic with baked beans tins If this is the real situation, then we shouldn t be over-focussed on the label on the beans tin! Nuclear cannot decarbonise the world on its own we need and, and, and not or, or, or
In conclusion..... We ve got a real challenge on our hands find every baked beans tin you can and bail like hell!! And DON T ask me if I m optimistic about the result!!