Nuclear Fusion Reaction

Types Of nuclear reactions. Nuclear Fission Reaction. Nuclear Fusion Reaction. Difference between nuclear fusion and nuclear fusion. Light Element Fission. Light Element Fusion. Nuclear Fusion on Sun. Beta Decay process happening in sun. A short explanation of D–D reaction, D–He(3) reaction, D–T reaction. the outstanding problem is the tritium supply. Binding energy curve.Energy partition in process of fusion reactions. How then can light element fusion reactions be initiated? A major explanation for all these above steps. A complete explanation by Syed Hammad Ali Gillani.

1. NUCLEAR FUSION REACTION Semester Fall 2020 Date ( Dec-1 st -2020) Submitted by : Syed Hammad Ali ( 19012510-085) Program : MSc-III / D Course Title : Plasma Physics Course Code : PHY-451 Department of Physics University of Gujrat

2. NUCLEAR REACTION: There are two types of reactions: Nuclear Fission and Nuclear Fusion. 2. Nuclear reaction: Hard to produce Powerful Use neutrons

3. Nuclear Fission process H eavy nucleus is bombarded with slow moving neutrons and two nuclei produced with more neutrons and high amount of energy is released. C onsidering U-235 as a heavy element. A slow moving neutron is set to strike on it and resulting two lighter nuclei(Ba-144 and Kr-89) produced along with 3 moving neutrons and high amount of energy which can be denoted as Q.

4. Nuclear F usion Nuclear fusion is when two small, light nuclei join together to make one heavy nucleus. Fusion reactions occur in stars where two hydrogen nuclei fuse together under high temperatures and pressure to form a nucleus of a helium isotope. There are a number of different nuclear fusion reactions happening in the Sun.

5. Light Nuclei In Nuclear Reaction: L ight element Fission: Bombardment of a deuterium nucleus with a neutron. The relevant reaction can be written as: R eaction leads to the desired neutron multiplication. T he energy released as calculated from the nuclear data show that E = -2.23 MeV . N egative sign indicates that energy is not actually released but must be supplied as an input to make the reaction take place. Clearly this would be unacceptable as a power source.   Light element Fusion: Hypothetical example again assume that a neutron collides with a deuterium nucleus. The resulting nuclear fusion reaction can be written as: In this case the nuclear data show that E = +6.27 MeV. The fusion reaction is energetically favorable for power production.  

6. Fusion Is Un-Acceptable For Power Source: The reaction consumes neutrons. Since there are no readily available sources of neutrons, this reaction is not self-sustainable. Therefore , it too is unacceptable as a practical power source. How then can light element fusion reactions be initiated? R eplace the neutron with another light element; that is, generate a nuclear reaction by having two light elements bombard each other, for instance two colliding deuterium nuclei. The advantage of this idea is that the lack of a chain reaction is easily overcome by simply providing a continuous supply of deuterium, which, unlike a neutron supply, is readily and inexpensively available.

7. Disadvantage Is That For Two D euterium Atoms: Deuterium is an isotope of Hydrogen atom which is proton. Proton and proton always repels. To undergo a nuclear reaction, their nuclei must be in very close proximity to each other, typically within a nuclear diameter. At these close distances, the inter-particle Coulomb potential produces a strong repulsive force between the two positively charged nuclei, which diverts the particle orbits and greatly reduces the likelihood of a nuclear reaction.

8. If Neglecting Issues: If these issues are not considered and attention is focused solely on the nuclear energy production of various fusion reactions without regard for how easy or difficult it may be to produce these reactions. Studies of the nuclear properties of light element fusion indicate that three such reactions may be advantageous for the production of nuclear energy. These involve deuterium, tritium, and helium-3, an isotope of helium.

9. Fusion In Sun: Inside the core of sun there is a small nuclei. Electrostatic force rip apart the nucleus because of repulsion of proton and proton. The strong nuclear force holds the nucleus.

10. The sun is much dense part so protons in it so protons collide in it. But somehow two protons collide and due to beta decay one proton converts into neutron. The Hydrogen-2 forms and cause explosion with release of energy. Hydrogen-2 continuously move and came near to another proton and become Helium-3 with release of tons of energy. The process continues and inside more helium-3 produces.

11. When two helium-3 nuclei came close to each other they came into a better combination and results in formation of one single helium-4 and results in release of energy. The 1 st step is slowest because we have to wait for occurrence of beta decay. The 3 rd step, when two helium-3 collides a helioum-4 nuclei occurs with release of two protons.

12. The D–D reaction : Nuclear interaction of two deuterium nuclei. This is the most desirable reaction in the sense of a virtually unlimited supply of inexpensive fuel, easily extracted from the ocean . The D–D reaction actually has two branches, each occurring with an approximately equal likelihood. The relevant reactions are as follows:

13. In terms of energy content the two reactions produce 0.82 and 1.01 MeV per nucleon respectively . Macroscopically this is equivalent to 78 × and 96 × MJ/kg of deuterium, typical of nuclear energy yields .  

14. The D– reaction :   It requires helium-3 as a component of the fuel and there are no natural supplies of this isotope on earth. The reaction is also difficult to achieve, but less so than for D–D. The reaction is worth discussing since the end products are all charged particles. The reaction is: The energy released per reaction is impressive, even by nuclear standards. The 18.3 MeV corresponds to 3.66 MeV per nucleon, which is macroscopically equivalent to 351 × MJ/kg of the combined D–He3 fuel.  

15. The D–T reaction : It can be written as: D–T reactions produce large numbers of neutrons and require a supply of tritium in order to be capable of continuous operation, but there is no natural tritium on earth. T he tritium is radioactive with a half-life of 12.26 years. This corresponds to 3.52 MeV per nucleon and is macroscopically equivalent to 338 × MJ/kg .  

16. The one outstanding problem is the tritium supply: The solution is to breed tritium in the blanket surrounding the region of D–T fusion reactions. The chemical element that is most favorable for breeding tritium is lithium. The nuclear reactions of primary interest are:

17. Both reactions produce tritium although the first reaction generates energy while the second one consumes energy . Also natural lithium comprises 7.4% and 92.6 % . Even though there is a much larger fraction of , nuclear data show that the reaction is much easier to initiate and as a result it is this reaction that dominates in the breeding of tritium. For present purposes one should assume that the issues have been satisfactorily resolved. Consequently, breeding T from solves the problem of sustaining the tritium supply, assuming adequate supplies of lithium are available.  

18. Energy partition in fusion reactions: The end products which forms after fusion reaction explicit large amount of energy appear in the form of kinetic energy. More importantly for the D–T reaction where one end product is electrically charged and the other is not. The distribution can be easily determined by making use of the well-satisfied assumption that the energy and momentum of each end product far surpasses that of the initial fusing nuclei. Suppose we have two sub-scripts of end products namely,1 and 2. The initially fusing particles are at rest. The conservation of energy and momentum relations before and after the fusion reaction involve only the end products and thus have the forms .

19. The end products have the form given below, = 0 After solving for and we got below equations, =   Energy partition in fusion reactions:

20. Energy partition in fusion reactions: As we see from above equations the kinetic energies are apportioned inversely with the mass, either we can say lighter particle carries most of the energy. For example the end produc t for D-T reaction where E = 17.6 MeV consist of alpha particle and neutron / = 4. Thus the kinetic energy of the alpha particle is equal to (1/5) E = 3.5 MeV, while that of the neutron is equal to (4/5)E = 14.1 MeV. The neutron energy is four times larger than that of the alpha particle. Rewrite the D–T fusion reaction in the slightly more convenient form D + T → α(3.5 MeV) + n(14.1 MeV). This reaction that dominates the world’s fusion research program.  

21. The binding energy curve and why it has the shape it does: The nuclear reactions are initiated for Heavy metals called fission reaction. Light element called fusion reaction. The nuclear reaction does not start for intermediate elements. This explanation is resulted from two observations. From binding energy vs atomic mass graph. The shape of binding energy curve.

22. The binding energy curve and why it has the shape it does: Graph explains binding forces of nuclei of heavy and light elements are weaker than intermediate elements. Shape arises due to geometric competition between strong nuclear forces which are short range and long range but weak coulombic forces.