FUSION Nature’s Fundamental ✺ Energy Source Edited by: Jim Leuer Written by: Dan Finkenthal Rick Lee Steve Rodecker* John Ray* Dave Schissel Pete Taylor Designed by: Fusion Technical Publications Group General Atomics Fusion Group 3550 General Atomics Court San Diego, CA 92121 For additional information about: • Fusion, please visit us on the World Wide Web at: http://FusionEd.gat.com/; • Tours of the DIII–D research facility please send e-mail to http://fusioned.gat.com/tours.html, or phone 858-455-3492; • Fusion education programs, please email to [email protected], or phone 858-455-3331; • Other General Atomics education programs, please e-mail to [email protected] * Chula Vista High School, Chula Vista, California The development and printing of this workbook was funded by a U.S. Department of Energy (DOE) grant: DE-FG03-95ER54310. We owe a special thanks to Dr. J. Willis and Dr. D. Priester of the DOE for their support of this educational effort. http://FusionEd.gat.com QTYUIOP Table of Contents: Page Preface . 3 Background Information: Fusion – Nature’s Fundamental Energy Source . 4 Station One: Energy . 13 Station Two: Plasma . 17 Station Three: Electromagnetic Spectrum . 21 Station Four: Radiation. 24 Station Five: Data Acquisition and Control . 28 Station Six: Engineering, Analysis, Design & Manufacturing . 31 Fusion Glossary . 34 © General Atomics 1996 http://FusionEd.gat.com QTYUIOP Preface This workbook is part of an educational outreach program sponsored by the General Atomics Fusion Group and the U.S. Department of Energy. The overall program con- sists of a pre-tour video to be shown in the classroom, a half-day educational tour of the DIII–D magnetic fusion research facility located at General Atomics in San Diego, California, and post-tour materials, of which this workbook is a major part. This work- book contains an overview of the fusion process and questions related to the tour’s six educational stations providing work assignments for students after they leave the site. The overall program was developed as a collaborative effort between fusion scien- tists and engineers at Generals Atomics and local San Diego school teachers. In developing this fusion tour package, the fusion educational team identified phe- nomena which are utilized in fusion energy research and which are important to a science curriculum. The tour focuses on connecting science principles taught in the classroom with phenomena used in indus- trial research. Buses can be provided on a limited basis to transport local students for the half-day tour. The tour begins with an initial presentation on the fusion process. Following this presentation, the students are split into small groups and rotate through six educational stations. The themes of the educational stations are: • DIII–D Tokamak & Fusion Power • Plasma: the Fourth State of Matter • Electromagnetic Spectrum • Radiation, Radioactivity & Risk Assessment • Data Acquisition and Control • Engineering Analysis, Design and Manufacturing A scientist or engineer at each station explains the phenomena to the students. Demonstrations and hands on equipment are part of most exhibits. Finally, the students are reassembled for a final question and answer session. An overview of the fusion process is contained in the first section. This is followed by six workbook sections containing questions related to fusion in general and the subjects covered in the DIII–D tour. Finally, a glossary of terms is presented. http://FusionEd.gat.com 3 QTYUIOP Fusion Workbook B a c FUSION k g Nature’s Fundamental Energy Source r o ✺ u Fossil Fuel Reserves n Fusion energy, the power source of the d stars, represents a potentially unlimited source of energy for humanity. For billions I of years nature has used fusion in stars as n f its preferred method to produce energy. o Millions of Hundreds r Years of Years m a 1900 2200 Fig. 2 - Fossil reserves are rapidly being depleted. t Dinosaur painting by John Klausmeyer. Courtesy of i U. of Michigan Museum of Natural History. o n Within a few centuries mankind will have depleted fuels that took millions of years to create (Fig. 2). Scientists are trying to replace this energy source with one Fig. 1 - Fusion destined to outlast our civilization: fusion. Energy In The Sun What Exactly is Fusion? Fusion involves the interaction of matter In a fusion reaction two light atoms and energy, and the scope of fusion combine, or fuse to form a heavier atom ranges from tiny subatomic particles to and release energy (Fig. 3). The fusion red super-giant stars. The last half cen- process accounts for the creation of all tury has seen scientists from all over the world working together Fig. 3 - Two lightweight elements are fused togeth- to harness and control the sun’s er, creating new elements and tremendous energy fusion process here on earth. Humanity owes its existence to the sun’s fusion engine. Fossil fuel deposits, the life blood of our civilization, form when plants cap- ture and store the sun’s energy. http://FusionEd.gat.com 4 QTYUIOP Fusion Workbook B a The Synthesis of Elements by Atomic Number Our tremendous coal deposits will last several more centuries, but c k He burning coal will come at a high H g environmental cost. H r Be He Since 1990, over 1.3 billion metric tons o per year of carbon dioxide have poured u He H into the atmosphere in the United States n d 1H + 1 H= 2 He 2 He + 2 He = 4 Be alone as a result of the combustion of coal and other fossil fuels. I He He n f C O o r m Be C a t i 2 He + 4 Be = 6 C 2 He + 6 C = 8 O o Existing nuclear power stations are Fig. 4 – New elements created during the fusion process. n able to provide about 20% of the U.S. elements heavier than hydrogen in the electricity needs. However, no new nuclear power plants are planned because of the universe (Fig. 4). In addition, during the perceived high plant cost, safety concerns fusion reaction a small amount of matter and waste disposal problems. is “lost,” that is, converted into energy. This energy powers the thermonuclear Alternative sources of electrical engines of the sun and stars, and pro- energy generation such as solar, geo- vides the energy for almost all life on thermal, and wind (renewable resources) earth. How can the energy source of are being developed, but they are still the stars help us on earth? expected to supply less than 15% of the nation’s electricity needs well into the There’s No Energy Crisis Now, But .... next century. Fusion is a strong candi- date to produce the enormous amount With relatively stable gas, oil, and elec- of electricity needed for the future in the tricity prices today, there is no longer world’s developing countries as well as much public concern about an energy cri- the U.S. sis. However, in the early part of the next century at the present rate of consump- Combustion, Fission and Fusion: How do they differ? tion the earth’s oil gauge will start to approach empty. Natural gas reserves While all these reactions produce heat, will hold out for about another century. they differ fundamentally in their atomic http://FusionEd.gat.com 5 QTYUIOP Fusion Workbook B a ingredients. Combustion is a chemical positively charged protons and c reaction and involves the joining or electrically neutral neutrons. During k separating of atoms to form molecules. a nuclear reaction the number of these g particles within the nucleus changes, r Atoms are made up of a heavy, com- sometimes creating different elements o pact, positively charged central core in the process. u called the nucleus and a number of light, n negatively charged particles called elec- d In the fission process, a large atom is trons. The fast moving electrons whirl split into smaller atoms releasing energy I around the nucleus and form a cloud from the nucleus (Fig. 6). Fission occurs n that completely surrounds the nucleus spontaneously in many radioactive mate- f and electrically balances the atom. rials or is induced by chain reactions, like o those occurring in today’s nuclear power r In the combustion process binding m energy is released as atoms are elec- a trically joined through the sharing of their Fig. 6 - Fission Reaction t outer most electrons. The resulting mol- i ecule is at a lower energy state than the o reacting atoms. The nucleus of each n atom is not changed in the reaction. The combustion of coal is a good example of Neutrons the chemical reaction in which carbon (C) and oxygen (O ) combine to form carbon 2 plants. The heavy element uranium (U) dioxide (CO ) and excess energy in the 2 is the primary fuel used in fission reac- form of heat (Fig. 5). tors. High energy neutrons circulating in the reactor core strike the nucleus of Fig. 5 - Combustion process uranium, splitting it apart to form lighter elements and releasing energy and neutrons to maintain the chain reaction. Fusion is the reverse of fission in that two light atoms are joined or fused to form a heavier element (Fig. 7) . Fusion involves the lightest elements in the peri- odic table. Hydrogen (H), the lightest of all elements, is the raw material used in the sun’s fusion engine. Under intense Fission and fusion are nuclear reactions temperature and pressure within our and involve changes in the foundation of stars, hydrogen atoms fuse to form the nucleus. The nucleus is made up of helium (He), the second lightest of all http://FusionEd.gat.com 6 QTYUIOP Fusion Workbook B a c n Deuterium P Like hydrogen, these isotopes have a k n Neutron single proton in their nucleus.