Inertial Confinement Fusion and Thermonuclear Reactors Milan Kalal

Inertial Confinement Fusion and Thermonuclear Reactors Milan Kalal Faculty of Nuclear Sciences and Physical Engineering Czech Technical University in Prague 115 19 Prague 1, Czech Republic ATHENS, November 20, 2013, Prague, Czech Republic

Background Situation Analysis Under current estimates the oil reserves will run out after 40 years, natural gas after 60 years and coal could last for two more centuries. Although energy provided by various renewable sources, such as water power plants, solar power plants, wind, geothermal energy etc. will undoubtedly play important niche roles at the beginning of this century, they will not be able to sustain the central baseload demands of future society. Presently, there are only two key players which need to be dealt with and relied upon to solve the problem: fission and fusion.

Fission or Fusion ? Both fission and fusion are forms of nuclear energy. However, they can be differentiated by various attributes, including their: • capital costs • safety • environmental impact • proliferation problems • fuel availability

Nuclear Energy Availability

Fission Assessment If the presently known reserves of fission fuels were used to sustain the full electrical energy needs of future populations, these fuels would probably not last for more than about 100 years using conventional thermal reactors with a once-through fuel cycle. However, such reserves could be made to last for thousands of years if they were efficiently used in breeder reactors with a reprocessed-fuel cycle. Uranium could also, in principle, be extracted from sea water, although we do not yet have the technology to achieve this.

Any Need for Fusion Energy? Electrical power generation in the 21 st century will be an industry worth tens of trillions of dollars, and there will be an assured and significant growth in demand from the developing world. The question really is whether we will have a fusion-reactor product that will be sufficiently attractive to compete in this marketplace? If we do, then fusion will be needed. Even more so should we take into account the climate change caused by heating of the planet due to an increase of the CO 2 in the atmosphere from burning fossile fuels.

This challenge must be resolved and solved today… Not 50 years from now

Fusion Assessment The First Generation Fusion Reaction

Lawson Criterion Ti ≈ 2 × 108 K n E ≥ 0. 5 × 10 20 m -3 s Example: - Reactor Chamber diameter 10 m - Typical energy released 340 MJ (equivalent of 75 kg TNT) - This is contained in 1 mg of D-T fuel - Energetic Amplification (gain) Q: For 17. 6 Me. V energy released and 30 ke. V (up to 60 million K) used for heating Q = 580. Notes: 1 e. V = 1. 6022 × 10 -19 joules; Average particle thermal kinetic energy is 1 e. V per 11, 600 K.

Fusion Assessment Lithium - the primary fuel for first-generation deuteriumtritium fusion reactors is significantly more abundant in the Earth's crust than either of the primary fission fuels, uranium or thorium. Lithium is also about 50 times more abundant than uranium in sea water. And deuterium, which is arguably the ultimate fusion fuel for second-generation deuterium-deuterium fusion, comprises 0. 015% of all of the hydrogen on Earth by atomic ratio. Thus, (deuterium) fusion is a fuel reserve that will be available to us for as long as the Earth exists.

Comparison of Safety of Fusion and Fission Power The stored energy in the fuel of a fission core is sufficient for about two years of operation. So although adequately safe fission reactors probably can be designed, this stored energy could, in principle, trigger severe accidents. In contrast, the amount of fuel in the core of a fusion reactor of whatever class that we can conceive of today - is sufficient, at most, for only a few seconds of operation. The fuel would also be continually replenished.

The other disadvantage of fission is that spent fuel rods in a fission core contain giga. Curies of radioactivity in the form of fission products and actinides, some with half-lives of hundreds or even millions of years. Such radionuclides therefore have to be disposed of into securely guarded repositories deep underground. In contrast, the main potential for generating radioactive waste from fusion comes from neutron activation of the structural materials that surround the reactor. A judicious choice of these materials can reduce fusion's potential biological hazard by many orders of magnitude relative to spent fission fuel. Indeed, such materials would not need to be disposed of in a long-term waste repository.

Perhaps most importantly, we must recognize that the exploitation of breeder reactors to extend the fission fuel reserves of uranium and/or thorium beyond this century will result in significant reprocessing traffic of 239 Pu and/or 233 U. Although international safeguards and security could no doubt be implemented, the diversion and exploitation of even a few kilograms of these materials would be a severe test of the public's stamina for this energy source. Therefore: !!! Let’s go Fusion !!!

Fusion process as a source of energy Plasma self-heating Tritium replenishment Li Electricity, Hydrogen

Fusion power plant: Electricity generation Fusion Power Core Tritium fuel Deuterium fuel Conventional Turbine Generator Heat Exchanger Fusion Plasma Tritium Breeding Blanket Electric Power Grid

Which Way to Go? There are two major approaches: 1. Magnetic Fusion Energy (MFE) (Tokamaks, Stellarators etc. ) 2. Inertial Fusion Energy (IFE) (High Power Lasers, Heavy-Ion Accelerators and Z-Pinch Drivers)

MAGNETIC CONFINEMENT

MFE (Tokamak) • • Low density: ~1012 cm– 3 , t >100 s Ultra high vacuum chamber necessary ~ 10 -11 Torr Whole in One System Life time of the whole system ~ 1 year…

International Thermonuclear Experimental Reactor (ITER)

ITER Ports for ECH&CD Central Solenoid Nb 3 Sn, 6 modules Outer Intercoil Structure Toroidal Field Coil Nb 3 Sn, 18, wedged Poloidal Field Coil Nb-Ti, 6 Machine Gravity Supports Blanket Module 421 modules Vacuum Vessel 9 sectors Cryostat, 24 m high x 28 m dia. Port Plug (IC Heating) 6 heating 3 test blankets 2 limiters/RH diagnostics Torus Cryopump 8 Divertor 54 cassettes

However !!! It is not clear that the conventional tokamak approach will lead to a practicable commercial power plant that anyone will be interested in buying. This is a consequence of its projected: • low power density • high capital cost • high complexity • expensive development path

INERTIAL CONFINEMENT

Scheme of the LFE

DIRECT DRIVE

Direct drive target ~1 mm

INDIRECT DRIVE

Indirect drive target Gold hohlraum X-ray laser 5 mm

IFE targets Indirect drive target (Hohlraum ~5 mm size) Cone shell target Au Cone PW laser for heating 1. 053µm Direct drive target ~1 mm size Plastic shell GEKKO XII for implosion 9 beams 0. 53µm 1. 2 k. J / 1 ns

LFE (Laser Fusion Energy) • • • High density: 1024 cm-3 (~100 atm) t >10 -10 s Low vacuum ~10 -5 Torr necessary Modular system; laser and target chamber are SEPARATED Small target size (~4 mm); negligible radioactivity Long lifetime of the target chamber ~ 30 years

Example of the Large Number Laser Beam Irradiating System

FIREX (Fast Ignition Realization Experiment) Purpose: Establishment of fast ignition physics and ignition demonstration Starting Conditions : high denisity compression(already achieved), 　 : heating by PW laser (1 ke. V already achieved） Overview of FIREX-II Heating laser 50 k. J 　Pulse width 10 ps Implosion laser 50 k. J

Palace of Nations at the United Nations Office of Geneva (UNOG)

Example of the IFE Reactor

A 100 ton of coal hopper runs a 1 GW Power Plant for 10 minutes. Same filled with IFE targets runs a 1 GW Power Plant for 7 years.

This is what we would really like…

Outlook into the IFE Future Alternative physics approaches are particularly important if we are ever to exploit the so-called advanced fusion fuels, such as D-D, D-3 He and p-11 B: D + D → T (1 Me. V) + p (3 Me. V) D + 3 He → 4 He + p + 18. 3 Me. V p + 11 B → 3 4 He + 8. 7 Me. V Such fuels suggest several advantages over conventional deuterium-tritium reactions. For example, they produce few or even no neutrons, and they could even directly convert charged fusion products into electricity without the need for a conventional thermal cycle. However, such fuels would require significantly higher plasma densities and temperatures to realize the same fusion power density as deuterium-tritium plasmas.

Challenges to be resolved in IFE development

In order to keep an appropriate IFE power plant going we must shoot about cryogenic targets at a rate of up to 10 Hz (108 each year) in a target chamber operating at 500 - 1500°C, possibly with liquid walls. The only way to do this will be to inject the targets into the target chamber at high speed, track them and hit them on the fly with the driver beams. This must be done with high precision (~± 200 µm [20 µm for direct drive] at 10 m), high reliability of delivery and without damaging the mechanically and thermally fragile targets. This challenge appears to be achievable, but will require a serious - and successful - development program. International cooperation on the largest possible scale would therefore be very desirable.

Steps taken by IAEA Progress can be done by: • Coordinating complementary experts related to IFE power plant design • Avoiding duplication of effort • Speeding progress by sharing knowledge, manpower and costs • Attracting the attention of and inviting experts of other fields who are interested in IFE power plant development

INTERNATIONAL ATOMIC ENERGY AGENCY Division of Physical and Chemical Sciences Physics Section First Research Coordination Meeting of the Coordinated Research Programme on Elements of Power Plant Design for Inertial Fusion Energy 21 -24 May 2001, Vienna, Austria

The Main Goal of CRP • Assess the status of Inertial Fusion Energy • Identify and contribute to the resolution of issues particularly related to the interfaces between the drivers, drivers targets and chambers: chambers 1) 2) 3) • Driver / Target Driver / Chamber / Target Identify and promote areas of possible collaborations between the countries and institutions participating in the CRP

Participants 10 countries including: Czech Republic (1) Hungary (1) India (1) Japan (2) Rep. of Korea (1) Poland (1) Russia (4) Spain (2) USA (2) Uzbekistan (1)

INTERNATIONAL ATOMIC ENERGY AGENCY Division of Physical and Chemical Sciences Physics Section First Research Co-ordination Meeting of the Co-ordinated Research Project on Pathways to energy from inertial fusion (IFE): An integrated approach 6 -10 November 2006 Vienna, Austria

INTERNATIONAL ATOMIC ENERGY AGENCY Division of Physical and Chemical Sciences Physics Section Second Research Co-ordination Meeting of the Co-ordinated Research Project on Pathways to energy from inertial fusion (IFE): An integrated approach 19 -23 May 2008 Prague, Czech Republic

Participants 14 countries including: Czech Republic (1) France (1) Germany (1) Hungary (1) India (1) Japan (2) Rep. of Korea (1) Poland (1) Romania (1) Russia (4) Spain (2) UK (1) USA (2) Uzbekistan (1) China promised during the APLS 2006 to join as well !!!

Current status in the IFE development

Fast Ignition Scheme

Compression and heating can be separated in fast ignition Compression by multiple laser beams Heating by ultra-intense laser pulse Ignition & Burn

Colin DANSON ORION

Mike DUNNE Hi. PER

National Ignition Facility (NIF) – Livermore, US

NIF will execute four major ignition campaigns in the next four years

NIF will help IFE to become MFE big competitor

LIFE: Laser Inertial Fusion-Fission Energy

Pure fusion solutions are technologically and economically challenging

Summary 1) Central Ignition Scheme Gain 10 exp. in 2010 in the U. S. 2) Fast Ignition Scheme Sub-ignition exp. in Japan & U. S. starting soon 3) Beyond Ignition toward Energy Production FIREX II (Single Shot High Gain): Japan Hi. PER (Burst Mode, High Gain): EU LIFE (2000 -4000 MWth): U. S. A. Z pinch reactor: U. S. A.

Summary 4) The world wide, complimentary effort on inertial fusion energy appears coordinated and healthy. 5) Many approaches are to be soon demonstrated or to be tested of ignition, high gain and energy production. 6) The ignition once demonstrated will be a sound mile stone for IFE and can be used as a firm bench mark for coming high gain and energy production. 7) The laser development and target production proceed to be ready for the coming high repetition era.