Nuclear Power Plant Lecture Notes PDF

Lecture Class EEGC-16 Nuclear Power Plant Sr.No. Contents 1. Introduction of the topic: Nuclear Power Plant 2. Definition & Basic Principal 3. Selection of site for the nuclear power plant...

Lecture Class EEGC-16 Nuclear Power Plant Sr.No. Contents 1. Introduction of the topic: Nuclear Power Plant 2. Definition & Basic Principal 3. Selection of site for the nuclear power plant 4. A Brief Review of Atomic Physics 5. Nuclear fuels 6. Schematic Arrangement of Nuclear Power Plant 7. Main parts of reactors and their Function 8. Main Parts & Its Explanation of Nuclear Reactor 9. Types of Nuclear Reactor 10. Control of Nuclear Reactor 11. Nuclear Waste Management 12. Advantages & Disadvantages of Nuclear Power Plant Department of Electrical and Electronics Engineering, B.I.T Deoghar campus, SK Mahto  Introduction of the topic: Nuclear Power Plant:- 1. Why? Nuclear Power Plant: In previous two chapters, we studied how electricity produced with the help of water & coal (known as Hydro & Thermal Power Plant). But, now a day’s our population as well as industrial sector increases, it means that demand of electrical power increases day by day. To fulfill this demand water & coal is of limited edition, so we required searching newly source of energy for production & fulfillment of electrical demand. Due to the high demand of electric power in all the fields, like industries, commercial, institutional and housings, etc. the shortage of electric power is becoming a big problem in day-to-day. It may be due to the technological development or need of the changing life styles of the human. In most of the summers all the cities and rural areas also facing the problem of power cuts, this is due to over burden of the power or usage of power is increasing day-by-day. Electric power has become an important and essential resources, it is used for all the purposes. Without electric power, a single day cannot move further. Keeping in mind the above problem, the R & D of government departments are establishing different modes of power generation plants. Nuclear power plant is one of the modes of the power generation. In this unit, we study about the nuclear power plant. To overcome the above mentioned problem, nuclear energy is a best solution to produce 92 90 94 huge amount of electrical energy. With the fission process of U , 232 235 Th, 239 Pu we have to produce this energy. This topic is similar to thermal power plant, in thermal power, coal is used to produce heat energy on the other hand in nuclear heat energy is produced with fission process of uranium, thorium & plutonium. 2. Definition of Nuclear Power Plant: The Power Plant which uses nuclear energy of radioactive material (Uranium or Thorium) converted into Electrical Energy is known as Nuclear Power Plant. Department of Electrical and Electronics Engineering, B.I.T Deoghar campus, SK Mahto 3. Basic Principal of Nuclear Power Plant: Every power plant has its own basic principal, on the basis of this the plant works. The Basic Principal of Nuclear Power Plant is given below: CE↔HE ↔KE ↔ME ↔EE As we know that, the freely moving neutrons bombarded with radioactive material (U235 or Th232) the heat energy produced, with the help of this heat energy & water a steam produced at high pressure & temperature. High pressure steam passes towards turbine where KE is converted to ME. We know that, turbine & generator are mechanically coupled through this combination an Electrical Energy is produced in Nuclear Power Plant. 4. NUCLEAR BINDING ENERGY: Nuclei are made up of protons and neutron, but the mass of a nucleus is always less than the sum of the individual masses of the protons and neutrons which constitute it. The difference is a measure of the nuclear binding energy which holds the nucleus together. The enormity of the nuclear binding energy can perhaps be better appreciated by comparing it to the binding energy of an electron in an atom. The comparison of the alpha particle binding energy with the binding energy of the electron in a hydrogen atom is shown below. The nuclear binding energies are on the order of a million times greater than the electron binding energies of atoms. Department of Electrical and Electronics Engineering, B.I.T Deoghar campus, SK Mahto  The binding energy curve is obtained by dividing the total nuclear binding energy by the number of nucleons. The fact that there is a peak in the binding energy curve in the region of stability near iron means that either the breakup of heavier nuclei (fission) or the combining of lighter nuclei (fusion) will yield nuclei which are more tightly bound (less mass per nucleon). The binding energies of nucleons are in the range of millions of electron volts compared to tens of eV for atomic electrons. Whereas an atomic transition might emit a photon in the range of a few electron volts, perhaps in the visible light region, nuclear transitions can emit gamma-rays with quantum energies in the MeV range. 5. MASS DEFECT: The distance between theoretical calculated mass and experimentally measured mass of nucleus is called mass defect. It is denoted by  m. Mass defect = (Theoretical calculated mass) - (measured mass of nucleus). i.e. (Sum of masses of protons and neutrons) – (measured mass of nucleus). In nuclear reactions, the energy that must be radiated or otherwise removed as binding energy may be in the form of electromagnetic waves, such as gamma radiation, or as heat. Again, however, no mass deficit can in theory appear until this radiation has been emitted and is no longer part of the system. The energy given off during either nuclear fusion or nuclear fission is the difference between the binding energies of the fuel and the fusion or fission products. In practice, Department of Electrical and Electronics Engineering, B.I.T Deoghar campus, SK Mahto  this energy may also be calculated from the substantial mass differences between the fuel and products. When the nucleons are grouped together to form a nucleus, they lose a small amount of mass, i.e. there is mass defect. This mass defect is released as (often radiant) energy according to the relation E = mc2; thus, binding energy = mass defect * c2. This energy holds the nucleons together and is known as binding energy. In fact, mass defect is a measure of the binding energy of the nucleus. The greater the mass defect, the greater is the binding energy of the nucleus. 6. NUCLEAR FISSION: When unstable heavy nuclei are bombarded with high energy neutrons, it splits into several smaller fragments. These fragments, or fission products, are about equal to half the original mass. This process is called Nuclear Fission. Two or three neutrons are also emitted. The sum of the masses of these fragments is less than the original mass. This “missing” mass (about 0.1 percent of the original mass) has been converted into energy. Fission can occur when a nucleus of a heavy atom captures a neutron, or it can happen spontaneously. 6.1 Controlled Nuclear Fission: To maintain a sustained controlled nuclear reaction, for every 2 or 3 neutrons released, only one must be allowed to strike another (uranium) nucleus. If this ratio is less than one then the reaction will die out; if it is greater than one it will grow uncontrolled (an atomic explosion). A neutron absorbing element must be present to control the amount Department of Electrical and Electronics Engineering, B.I.T Deoghar campus, SK Mahto  of free neutrons in the reaction space. Most reactors are controlled by means of control rods that are made of a strongly neutron-absorbent material such as boron or cadmium. In addition to the need to capture neutrons, the neutrons often have too much kinetic energy. These fast neutrons are slowed through the use of a moderator such as heavy water and ordinary water. Some reactors use graphite as a moderator, but this design has several problems. Once the fast neutrons have been slowed, they are more likely to produce further nuclear fissions or be absorbed by the control rod. 6.2 Spontaneous Nuclear Fission: The spontaneous nuclear fission rate is the probability per second that a given atom will fission spontaneously that is, without any external intervention. If a spontaneous fission occurs before the bomb is fully ready, it could fizzle. Plutonium 239 has a very high spontaneous fission rate compared to the spontaneous fission rate of uranium 235. Consideration of the spontaneous fission rate of each material is required when designing nuclear weapons. Department of Electrical and Electronics Engineering, B.I.T Deoghar campus, SK Mahto 7. NUCLEAR FUSION: In nuclear physics and nuclear chemistry, nuclear fusion is the process by which multiple like-charged atomic nuclei join together to form a heavier nucleus. It is accompanied by the release or absorption of energy, which allows matter to enter a plasma state. The fusion of two nuclei with lower mass than iron (which, along with nickel, has the largest binding energy per nucleon) generally releases energy while the fusion of nuclei heavier than iron absorbs energy; vice-versa for the reverse process, nuclear fission. Nuclear energy can also be released by fusion of two light elements (elements with low atomic numbers). The power that fuels the sun and the stars is nuclear fusion. In a hydrogen bomb, two isotopes of hydrogen, deuterium and tritium are fused to form a nucleus of helium and a neutron. This fusion releases 17.6 MeV of energy. Unlike nuclear fission, there is no limit on the amount of the fusion that can occur. Department of Electrical and Electronics Engineering, B.I.T Deoghar campus, SK Mahto 8. Comparison of Fusion and Fission Processes: Sl. No. Fusion Fission 1. Light elements fuse together with Energy is released by the release of energy bombardment of heavy nuclear with neutrons. The nucleus splits into fragments of equal mass 2. Heavy mass will be converted in to Light mass will be converted into energy energy 3. Amount of radioactive material In fission process it is very high consumed in a fusion process is very low 4. Health hazard is very less Health hazard is high due to higher radioactive materials 5. Construction of controlled fusion It is possible to construct self- reactors is very difficult sustained fission reactors and have positive energy release 6. Very very high temperature are Manageable temperatures are required for fusion process (≥ 30 obtained million degrees) Department of Electrical and Electronics Engineering, B.I.T Deoghar campus, SK Mahto 9. Site Selection of Nuclear Power Station: (1) Availability of water: Sufficient supply of neutral water is obvious for generating steam & cooling purposes in nuclear power station. (2) Disposal of Waste: The wastes of nuclear power station are radioactive and may cause severe health hazards. Because of this, special care to be taken during disposal of wastes of nuclear power plant. The wastes must be buried in sufficient deep from earth level or these must be disposed off in sea quite away from the sea share. (3) Distance from Populated Area: As there is always a probability of radioactivity, it is always preferable to locate a nuclear station sufficiently away from populated area. (4) Transportation Facilities: During commissioning period, heavy equipments to be erected, which to be transported from manufacturer site. So good railways and road ways availabilities are required. (5) Skilled Person Requirement: For availability of skilled manpower to run & handle the plant also good public transport should also be present at the site. (6) Near to Load Centre: As we know that generating stations are far away from thickly populated area, so to reduce the transmission & distribution losses the plant should located near to load centre. (7) Storage of Nuclear Material: the nuclear materials are radioactive, which are dangerous to health to overcome this drawback a separate arrangement provided for storage of material. (8) Geographical Condition: the radioactive material are very dangerous to human health & all living organisms, if due to earthquake chances occurs to blast the reactors to avoided this the area should be free from earthquake. Department of Electrical and Electronics Engineering, B.I.T Deoghar campus, SK Mahto