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Presentation on energy iter2017 january

Feb 07, 2017

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When we look up at night and view the stars, everything we see is shinning because of distant nuclear fusion -Carl SaganAmerican astronomer cosmologist and astrophysicist(1934-1996)

NUCLEAR FUSIONInternational Thermonuclear Experimental Reactor (ITER)DEPARTMENT OF MATERIAL SCIENCE AND ENGINEERINGAFRICAN UNIVERSITY OF SCIENCE AND TECHNOLOGY, ABUJA Cooper Kollie LACKAY 40447

Lecturer: Prof. Esidor NTSOENZOK JANUARY 26, 2017

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TABLE OF CONTENTSINTRODUCTION

FUNDAMENTALS OF THE PRODUCTION OF ENERGY BY FUSION

DESCRIPTION OF ITER

State of art of ITER The Tokamak

CHALLENGES AND SOLUTIONS Material Issues Proposed SolutionsFUTURE OF ITER

RECOMMENDATIONS

CONCLUSION

REFERENCES

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INTRODUCTION

The first fusion experiments in the 1930s, fusion physics laboratories were established in nearly every industrialized nation. By the mid-1950s "fusion machines" were operating in the Soviet Union, the United Kingdom, the United States, France, Germany and Japan. A major breakthrough occurred in 1968 in the Soviet Union.

The Soviet machine was a doughnut-shaped magnetic confinement device called a tokamak. The world's first tokamak device: the Russian T1 Tokamak at the Kurchatov Institute in Moscow. It was the first device to use a stainless steel liner within a copper vacuum chamber(Ostwald, 1993)4

INTRODUCTION

ITER (International Thermonuclear Experimental Reactor) is the world's largest experimental nuclear fusion reactor which aim is to deliver nuclear fusion on a commercial scale, offering safe, limitless and environmentally responsible energy.

The particular magnetic configuration chosen for ITER is the Tokamak.

This choice was driven by the vast, successful experience with tokamak experiments around the world over the last forty years.

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FUNDAMENTALS OF THE PRODUCTION OF ENERGY BY FUSIONFusion is the process that powers the sun and the stars.

Deuterium is plentifully available in ordinary water.

Tritium can be produced by combining the fusion neutron with the abundant light metal lithium.

Fig:1. NUCLEAR-FUSION REACTION (Ostwald, 1993) 6

FUNDAMENTALS OF THE PRODUCTION OF ENERGY BY FUSION

First two hydrogen nuclei1H+(protons) fuse into a deuterium nucleus2H+, releasing a positron e+and an electron neutrino eas one proton changes into a neutron:

The resulting deuterium nucleus reacts with another proton, resulting in the light helium isotope3He2+and a gamma ray photon :

In the reaction of theppIbranch helium-4 comes from fusing two of the helium-3 nuclei produced:

The fusion of a deuterium and a tritium nucleus creates an alpha particle, a neutron and 17.6 MeV energy.

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DESCRIPTION OF ITER MAIN PARAMETERS

Plasma Major Radius6.2mToroidal Field on Axis5.3TPlasma Minor Radius2.0mFusion Power500MWPlasma Volume840m3Burn Flat Top>400sPlasma Current15.0MAPower Amplification>10x

Fig: 2.Schematic diagram of the components of the ITER tokamak ITER Organization

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DESCRIPTION OF ITER STATE OF ART OF ITER

Fig 3:ITER VIEW 9

DESCRIPTION OF ITER STATE OF ART OF ITER Fig 4: The decision to site the ITER Project in southern France was made by the ITER Members in June 2005.

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The Tokamak

DESCRIPTION OF ITERTokamak is a toroidal apparatus for producing controlled fusion reactions in hot plasma.The tokamak is a nearly axisymmetric torusThe principal non-symmetric aspect is the set of discrete magnetic field coils which generate the dominant toroidal magnetic field

Fig 5: Tokamak

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CHALLENGES AND SOLUTIONSCHALLENGESIMPURITY DESORPTIONLight impurities like C, N, H2O, and O are frequently adsorbed on chamber walls. Surface impurities come from residual gases present in the chamber, redeposition of sputtered atoms, and segregation of the surface of impurities present in the wall material.

BLISTERINGBlistering can be a source of plasma contamination when the heat flux is high, shortening the lifetime of plasma facing components. Blistering can occur when the critical helium concentration occurs inside the metal before it occurs at the surface. Blistering and flaking may be a problem in cases where sputtering rates are low, most of the alphas are at 3.5MeV, and the alpha flux is high.

AUSTENITEAustenitic stainless steel currently used.

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CHALLENGES AND SOLUTIONSOLUTIONSThe position solution to impurity desorption is to bake out the vacuum chamber which will helps to clean most of the adsorbed mono-layers of light impurities. Plasma discharges are often repeated for days on large experiments to clean the chamber walls. Plasma particles and photons striking the walls may stimulate desorption to remove impurities.

BLISTERING: If the alpha flux is low, if the alphas are more uniformly distributed in energy, or if sputtering rates are high, then, blistering is not likely to be a serious problem.

For austenitic stainless steel, the inner surface should be replace every few years

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FUTURE OF ITER EXPERIMENTThe ITER experiments baseline mode of operation targets of the thermonuclear gain parameter Q (Pfus/Pin)= 10 with Pfus= 500 MW and a pulse length of about 400 s .

An extended mode of operation at Q = 5 (Pfus = 300 MW) with a pulse length of 1000s is also planned.

ITERs principal parameters are largely determined by these objectives and a handful of relations derived from engineering requirements and the tokamak database. Those parameters are R = 6.2m, a = 2.0m, Ip = 15MA, and BT (magneticfluxdensity)= 5.3T. The total plasma volume is about 850 m3; the energy in the toroidal field magnets at full strength is about 41 GJ.

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FUTURE OF ITERThe experimental fusion reactor, known as ITER, will bring us closer to: Harnessing the power of a clean, safe and inexhaustible source of energyNo greenhouse gasesSuitable for large scale power productionRelatively small amounts of radioactive waste on Relatively short time scales (