Fusion for Neutrons: Fusion Neutron Sources for the development of Fusion Energy

Transcription

1 Fusion for Neutrons: Fusion Neutron Sources for the development of Fusion Energy M. P. Gryaznevich Culham Science Centre, Abingdon, UK - 1 -

2 Fusion Reactor as an Advanced Neutron Source: F4N Concept High-output neutron sources (NS) are required in fundamental science and in many modern special and innovative technologies, - and by nuclear industry to support energy production by cleaning waste and breeding fuel, or as a core of a new generation reactors In near term, DT fusion may become the most powerful NS. To date, tokamaks have already demonstrated MeV in DT reaction and MeV in DD reaction. Super Compact Spherical Tokamak Fusion Neutron Source can become a most intense Neutron Source today - 2 -

3 World Energy Crisis

4 Fossil Energy Most of the world energy production is based on fossil carbon fuels: oil, gas, coal Growing demand - India, China, newly developing world Oil Peak has happened, gas underpriced Climate change demands carbon-free energy Environmental Pollution Politics

5 Existing Alternatives Renewable energy (wind, wave, solar, hydro, biofuels) is an attractive option at present and offer long term, clean energy reserves. However : Low energy density and still expensive Fluctuates in time requiring storage systems Can not satisfy large fraction of energy demand (solar 6GW in 2008) In some cases, bad environmental impact, at expense of food production (biofuels)

6 Nuclear Energy (fission) Existing 442 Nuclear Power Stations: - produce ~20% of world electricity - in > 30 countries - up to 80% in some countries (France) About 45 reactors are under construction, hundreds of new plants planned Safe, clean, relatively inexpensive, but 3 problems: 1. Long lived radioactive waste products (many thousands of years) that require transportation, storage and re-processing, must be taken care of 2. Emerging uranium fuel shortage 3. Public concerns on safety and proliferation

7 We hope, no!

8 What is the Solution for Safe, Clean and Unlimited Energy Source?

9 IAEA...occurs when two light nuclei are forced together, producing a larger nucleus The combined mass of the two small nuclei is greater than the mass of the nucleus they produce M Gryaznevich, Fusion Overview, Assessment of Nuclear Fusion Programme on Thailand, Pathum Thani, Thailand, 18-19/08/2008 The extra mass is changed into energy We can calculate the energy released using Einstein s famous equation: E = mc 2 1kg of fuel would supply the same amount of energy as 1,000,000 kg of coal! 10 g of Deuterium (from 500 litres of water) and 15g of Tritium produces enough fuel for the lifetime electricity needs of an average person in an industrialised country!! - 9 -

10 Nuclear Fusion Dream Sun on Earth: Controlled Nuclear Fusion Virtually unlimited fuel supply Deuterium from water + Tritium from Lithium No long lived radioactive waste 50 years of R&D, tremendous progress in the last decade Controlled Fusion reaction demonstrated on JET (UK) and TFTR (US)

11 16 MW Fusion Power produced more than 10 years ago! so it works Fusion power in JET (1991, 1997) and in TFTR (1994)

12 The Beginning of Fusion The 1946 Thompson, Blackman patent for a Fusion Reactor..a powerful neutron source. Also a powerful source of heat Based on a toroidal Pinch Parameters were modest: R / a = 1.3m / 0.3m, I p = 0.5MA classical confinement was assumed : t = 65s T = 500keV Hence D-D fusion would be achievable ZETA at Harwell, : R/a=1.5m / 0.48m, I p = MA Confinement was highly anomalous: t ~ 1ms T~ 0.16keV - Beginning of a long path to Fusion Energy!

13 What is Fusion Power Plant? - Bass Pease, 1956 inside: Deuterium Helium Tritium neutron Tokamak

14 What is the TOKAMAK? Tokamak, from the Russian words: toroidalnaya kamera and magnitnaya katushka meaning toroidal chamber and magnetic coil Tokamak is a toroidal plasma confinement device with: Toroidal Field coils to provide a toroidal magnetic field Transformer with a primary winding to produce a toroidal current in the plasma The current generates a poloidal magnetic field and therefore twisted field lines which creates a perfect trap Other coils shape the plasma September

15 World Fusion Activities: 59 tokamaks are operational (plus stellarators, pinches, spheromaks) Asia: 26 (14 in Japan, 5 in China) Europe: 15 (6 in Russia, 2 in UK, 2 in Germany) America: 12 (7 in USA, 3 in Brazil) Africa: 1 10 under construction International magnetic fusion research budget is 1-2 BEuro/year ITER funded by International co-operation (10 BUSD)

16 Magnetic fusion experiments around the world Experiments all over the world progress the understanding of plasma physics and improve plasma performance and confinement.

17 When? Fusion Power Pulse duration Q = P out /P in MW ~1 sec < <30 mi n >10 700MW ~2050 (?) ~150- ~1 day ~ MW Steady progress, but long way

18 New approach: At the IAEA Fusion Energy Conference at Geneva in 2008, Russia, China and US announced that Fusion science and technology are developed enough for construction of fusion-fission reactors that are able to clean (transmutate) nuclear waste and produce (breed) nuclear fuel from the spent one. This is much faster way to commercial fusion compared with the traditional pure fusion approach for electricity production.

19 Fusion Role in Nuclear Energy Production Nuclear fusion reaction produces high-energy neutrons, which can be used to: - Recycle high level nuclear waste from conventional nuclear fission reactors into new fissile fuel or low-radioactive waste - Produce enough fuel to top-up fission reactor - Produce energy and tritium for self sufficiency Combination of fission + fusion reactors becomes selfsufficient and environmentally clean, which dramatically improves both the safety and economics of nuclear energy production Fusion with 60 years of R&D is now ready to help in resolving main problems of Nuclear Power production: fuel, waste, proliferation

20 Fusion for Energy: 3 options Pure Fusion: ITER DEMO Power Plant Fusion core for hybrid reactor, i.e. Fusion driven Subcritical Nuclear Reactor Fusion as a Neutron Source, or F4N

21 Challenges for Fusion Energy production: commercialisation: -- Pure Fusion (ITER line): year target -- Hybrid for energy production: same or less (?) -- Fusion for closing waste transmutation: nuclear fuel cycle: today 3 stages of Fusion Hybrid Power Fusion Development: Power Development: -- compact Compact neutron source for for fusion-driven systems -- Multi Functional Tokamak Reactor Prototype -- commercial Commercial Fusion Compact or Fusion-Fission Reactor Tokamak produces a lot of neutrons construction of reliable neutron source (F4N) in the nearest task for Fusion development

22 Neutron Sources

23 Thermal neutron flux available at various neutron sources as a function of time since Chadwick s discovery of the neutron IAEA-TECDOC-1439 Spherical Tokamak SCFNS Since 1970 reactor sources are close to saturation of the flux reached Spallation sources have overcome reactors in 90s, but flux growth is rather slow Tokamak FNS reaching n/s may become the leader

24 Most powerful neutron sources in the world (* - projects) NS Type relative price of neutrons (from UT report) Facility (location), used nuclides Deposited Power, MW S/S (Peak) Rate, n/s S/S (Peak) Neutron Power Output, MW S/S (Peak) Max. Neutron Flux Density, n/cm 2 s 1. Fission reactors ILL (Grenoble, France), U Accelerators Tokamaks 1 PIK (Gatchina, Russia), U IBR-2 (Dubna, Russia), Pu239 2 (1500) 0.6 (500) 0.03 (25) SNS (ORNL), p, Hg 1 (30000) 1 (30000) 0.3 (10000) LANSCE (LLNL), p, W, Pb, Bi 0.1 (10000) 0.1 (10000) 0.03 (3000) *IFMIF (being negotiated), D, Li JET (Abingdon, UK), D, T 0 (16) 0 (60) 0 (13) *JT-60SA (Naka, Japan), D 0.01 (0.5) 0.01 (2) 0 (0.4) *ITER (Cadarache, France), D, T *SCFNS, D, T > Inertial fusion *LIFE (LLNL), D, T 1000 (2100)

25 Fusion Reactions Fusion requires high plasma temperature, density & confinement D - D fusion D + D n (2.45 MeV) + 3 He (0.82 MeV) D-T fusion D + T n (14.06 MeV) + 4 He(3.52 MeV) Other reactions possible, but have not been demonstrated in fusion devices at commercially required level Fusion produces 14 MeV or 2.45 MeV neutrons. Variable energy output is also possible

26 Challenges for Fusion for Neutrons to be competitive with other neutron sources: Free neutrons thermal Transmutation Fuel breeding n-flux > n/cm 2 s n-source rate > n/s n-source rate > n/s - and many applications require much less neutrons (<10 14 n/cm 2 s), i.e. diagnostics, isotopes, research etc. Compact tokamaks with a few MW fusion power may compete with contemporary neutron sources (fission reactors and spallation neutron sources)

27 Fission & Fusion Neutron Sources Most powerful neutron source based on nuclear reactor gives the same useful neutron production rate as a 3 MW fusion neutron source

28 What else Neutron Sources can do? Neutron Source is a nice device to show where the atoms are and also a nice device to show where you can get a Nobel Prize!

29 Fusion Neutron Sources

30 Options for Fusion Neutron Source Auxiliary heating, T consumption and magnetic systems set the cost of a demonstration experiment Classical tokamaks R/a > 2.5: - superconducting coils are possible for providing high TF ~6 T, but leads to high T consumption (big device size) Spherical tokamaks R/a < 2.0: - copper coils with water cooling are possible, only power dissipation (running costs) constrains TF in ST FNS - stress limit (TF) favours the lowest aspect ratio - high beta in ST ensures no physics limitations - neutron balance of ST is optimal at R/a ~ 1.6 Running costs > $500 M/year-100% Capital cost as low as $50M Running cost < $50 M/year-100%

31 Fusion Reactor as an Advanced Neutron Source Many proposals of FNS have been considered: - conventional tokamaks: FDF (Stambaugh); ITERtype (SABR Stacey, Rebut); FDS-1 (Wu); FEB (Feng) - mainly considered as prototypes of fusion-fission hybrids - superconductive (big, expensive to build) or Cu (pulsed, high operating costs) - need to breed tritium - high divertor and wall load, high NB power - rely on ITER technologies FEB-E FDF FDS SABR

32 Can we improve the tokamak?

33 25 Years of ST Research Prototypes of a Compact Fusion Neutron Source MAST, START and about 20 other STs around the World In operation,

34 Spherical tokamak as an Advanced Neutron Source Texas CFNS, US Intensive studies during last 15 years R/a, m I p /B t, ka/t k P in /P fus MW VNS UK 0.8/ / /32 CFT UK 0.85/55 6.5/ /35 CTF US 1.2/0.8 12/ /150 CFNS US 1.35/ / /100 STEP UK 1.2/0.75 5/ /30 JUST RF 2/1 5.3/ /62 FDF China 1.4/ / /100 STPP US 0.7/0.5 11/3 3 30/300 CVNS UK 0.57/ / /16 TIN RF 0.47/0.28 3/ /2 CSTPP US 0.47/0/28 14/ /310 SCFNS UK 0.5/ / /2 FDS-ST, China US CTF, Peng JUST, RF UKAEA CTF

35 Super Compact Fusion Neutron Source

36 Mission of Super Compact FNS To show feasibility and advantages of the ST concept as a powerful neutron source To demonstrate and use steady-state fully non-inductive regime To operate with tritium, contributing with this to the mainstream Fusion research in many areas (T handling, material/component testing, diagnostics, safety, remote handling etc.) To be the first demonstration of possibility for commercial application of Fusion today

37 Strategy for Design Work Diagram of Design Options Research: Small ST, no neutrons, HTS option Medical isotopes, diagnostics, research: 5-50 kw SCFNS, DD, s/s or pulsed less Power Core Design: R=0.5 m, 2-5 MW steady state DT SCFNS more Power MA burner: MW, long pulse SCFNS breeder, transmutator etc: >100 MW high-q CFNS, s/s or pulsed

38 Simplest SCFNS Main SCFNS parameters, mainly interpolation: R/a = 0.5m/0.3m, k = 2.75, I pl =1.5MA, B t =1.5T, P NBI ~5-10MW, E NBI ~ keV - Size: between START and MAST. Same as QUEST, Pegasus - Elongation: NSTX/MAST-U - Plasma current: NSTX/MAST-U level. Three times higher toroidal field - NSTX/MAST-U heating power, but up to two times higher beam energy Useful test area ~ 10 m 2 ; fusion rate n/s thermal rate 5x10 14 n/cm 2 s (up to10 15 n/cm 2 s) Cu/Be Be, 208 Pb, 238 U D 2 O, C Be shielding Inner vessel TF coils Outer vessel Divertor coils NBI ports PF coils

39 Other Super Compact designs Analysis of two ST FNS designs closest in size (R < 0.6 m) confirm feasibility of SCFNS UKAEA VNS, T C Hender et al, FED 45 (1999) R = 0.57 m, B t = 1.5 T, I p = 6.8 MA, k = 2.3, P NB = 25 MW GA ST Pilot Plant, R Stambaugh et al, FT 33 (1998) R = 0.47 m, B t = 9.6 T, I p = 14 MA, k = 3.0, P NB = 50 MW

40 General Atomics ST Pilot Plant Motivation for compact GA ST confirms feasibility of ST path to commercial application as an FNS: - ST approach can progress from Pilot Plant to Power Plant just by doubling or tripling the linear dimensions of the device with no changes in technology - ST approach has the two key features of an executable commercialization strategy: - a low-cost pilot plant that can attract commercial cost sharing at an affordable level and with minimal financial risks; - and a strong economy of scale leading to compact Power Plants - The fact that a viable concept for a Pilot Plant exists is the principal attraction to government of the compact ST approach to commercial transition

41 Advantages of High Magnetic Field in FNS Fusion power from DT thermal reaction P FUS ~ b 2 B 4 MAST results confirm good prospects for beamplasma DD reaction Plasma energy confinement in ST ~ B 1-1.4, so better prospect for heating and current drive Stability improves at high field Better prospects for RF heating and current drive Overall: higher field cheaper neutrons (also better prospects for energy production) Recent development of a new generation of High Temperature Superconductors (2G HTS) opens promising opportunities for high field magnets in STs

42 New ideas High Temperature Superconductors (HTS) The recent development of High Temperature superconductors could have far-reaching application. They give similar performance to LTS but at around 77K (liquid nitrogen) rather than 4K (liquid helium) temperatures.

43 First Result of HTS Coil Tests on Tokamak GOLEM Prague, August October 2011 (in a scope of IEAE Coordinated Research Project F Utilisation of a Network of Small Magnetic Confinement Fusion Devices for Mainstream Fusion Research ) Tokamak Solutions UK In collaboration with: Oxford Instruments, Technical University of Prague, IPP Prague, Forma Machinery LV Cryostat installed on Golem tokamak Nitrogen coming out through ventilation holes during plasma pulse 43

44 First Tokamak with HTS Coils New HTS coils LN HTS 6 turns 0.1x12mm tape Kapton isolation ~1x12mm coil Small tokamak GOLEM at Technical University of Prague 44

45 First Tokamak with HTS Coils Upper PF coil cryostat winding the coil filling with liquid nitrogen Power Supply LN Supply 45

46 resistivity First Operations of a Tokamak with HTS Coils time Superconductivity achieved! Plasma pulse with 0.3kA in HTS coils First tests on 29/08/2011 First tests with plasma 28/09/2011 Maximum current of 1kA achieved on 29/09/

47 Super Compact Fusion Neutron Source (F4N) Concept is based on the latest developments in Fusion and Nuclear Physics & Technologies

48 How will we build the SCFNS? The engineering is now standard practice in fusion laboratories and with their component suppliers, but now needs to be brought to commercial levels of reliability, safety, cost and volume. 20 prototypes of the CFR, which is based on the novel spherical tokamak design, are currently operational. The construction venture will work with the current best suppliers and industries from several countries, including Hitachi, Toshiba, Mitsubishi, Fuji (Japan), Northern Plant, Efremov (Russia), Princeton (US), Culham (UK)

49 How will we build the SCFNS? 20 Spherical Tokamaks built in last 15 years by leading Nuclear and Fusion Industries CPD, TOSHIBA, Japan, 2005 Globus-M, North Plant, Russia, 2000 UTST, Fuji, Japan, 2008 PF coils EF coils TF coils EF coi PF coi ST plasm QUEST, TOSHIBA, Japan, 2008 KTM, Efremov Institute, Russia,

50 How will we build the SCFNS? Both VV and TFC are changed after reaching the fluence limit or in a case of accident Changing the vacuum vessel and TF coils

51 CONCLUSIONS High-output Neutron Sources are required in fundamental science and commercial applications, including isotope production and nuclear industry In near term, DT fusion may become the most powerful NS FNS with Mega-Watt rates ( n/s) will have strong influence on the global energy production strategy as well as on the development of fusion & nuclear science and technologies Compact ST may become the most efficient and feasible Fusion Neutron Source and an optimal core for a fission-fusion hybrid

52 CONCLUSIONS Development of a steady-state reliable Neutron Source in the nearest task for Fusion The ST path to commercial application of Fusion can start from a Compact ST with R as low as 0.5 m and NBP 5-10 MW It seems important to have an achievable goal in the not too distant future in order to encourage the large goal, in this case pure fusion H Bethe, Physics Today