nuclear power stations

TERM PAPER
DONE BY: SUMEET SONI
LECTURER: JAMES MUNYITHYA
I.D NO: 637294
COURSE: NSC2215

TABLE OF CONTENTS
TOPIC PAGE
INTRODUCTION…………………………………………………………………………2
NUCLEAR REACTIONS……………………………………………………………….3
HOW IT WORKS…………………………………………………………………………5
BENEFITS OF NUCLEAR POWER STATIONS…………………………………9
DRAWBACKS OF NUCLEAR POWER STATIONS…………………………….10
CASE STUDY……………………………………………………………………………11
CONCLUSION…………………………………………………………………………..13
REFERENCES………………………………………………………………………….14

NUCLEAR POWER STATIONS

INTRODUCTION “Nuclear power”,” nuclear energy” when these terms come to mind, most people usually start thinking of bombs, destruction, terrorism and deformed humans which in fact are the four least occurring things in the nuclear power field. A nuclear power station is simply a thermal power station whereby it uses a nuclear reactor as the heat source. The nuclear power plants produce this electricity though a heat generating process known as fission which will be discussed further in this research paper. Nuclear power plants are usually considered to be base load stations, since fuel is a small part of the cost of production. So, most of all the nuclear energy comes in the form of production of electricity. Nuclear power stations take up of up to 16% of the worlds electricity production which may not seem a lot but when you think of the amount of electricity we use every single day, it may bring out a vivid understanding as to how vital nuclear power is to us all. Nuclear power stations are a growing trend these days mainly because it is much more environmentally friendly than other forms of energy production which clearly does not affect the global warming trend. On the other had if uncontrolled, it can be really fatal which is why it is not a regulated energy source but then again, where would we be without it?

NUCLEAR REACTIONS
A nuclear reaction occurs when a single nucleus breaks into two parts, or in other words two nuclei come close together, exert forces on one another hence undergo a change.
Conditions for a nuclear reaction to occur
At least one of the nuclei must be “naked”, that is having all its electrons removed. This can be done by raising the temperatures to very high values such as 100,000 degrees. If the nuclei are surrounded by electrons as they are under the normal conditions on earth, it is not possible for a nuclear reaction to occur because the electron clouds of the two nuclei will repel each other since they are like charges(negative) and will most likely “bounce off” hence not completing the nuclear reaction.
Extremely high energy is needed for the nuclear reaction to occur. This is because both the nuclei are positively charged and so a lot of energy is needed to break the electrical repulsion. This can be in the following 2 ways:
1. It can be done in an accelerator laboratory whereby a dynamitron is used to accelerate the nuclei to very high speeds using strong electric and magnetic forces. The accelerator then produces a narrow beam of nuclei which are travelling in a straight line.
2. It can also be done at very high temperatures where the atoms do not exist, they are only separated by the nuclei and electrons. Here the particles are moving really fast and in all random directions.
Here are some examples of nuclear reactions:
Suppose the beam consists of the rare oxygen isotope,178O. The following is called a transfer reaction:

One of the 9 neutrons on the oxygen has transferred to the carbon. Another example: suppose you had a beam of heavy hydrogen, 21H, and a target of neon, the common isotope, 20Ne. The transfer reaction,

might occur. Again a neutron is transferred.
Other examples include:

HOW IT WORKS
Inside the nuclear power plant
In simple terms, In order to turn nuclear fission into electrical energy, nuclear power plant operators have to control the energy given off by the enriched uranium and allow it to heat water into steam.
Enriched uranium typically is formed into inch-long (2.5-centimeter-long) pellets, each with approximately the same diameter as a dime. Next, the pellets are arranged into long rods, and the rods are collected together into bundles. The bundles are submerged in water inside a pressure vessel. The water acts as a coolant. Left to its own devices, the uranium would eventually overheat and melt.

Then to prevent overheating, control rods are used, which are made of a specific material which is designed to absorb neutrons. These rods are inserted into the uranium bundle when the rate of heat in the nuclear reactor is getting out of control. They are also removed from the uranium so that more heat is produced. The control rods can also be dipped in the uranium to completely stop the reaction incase of an accident.
The uranium is simply used as a very powerful heat source. It is used to heat the water in order to form steam. The steam therefore is used to spin the turbines which again spin the generators to produce electricity.
In some nuclear power plants, the steam from the reactor goes through a secondary, intermediate heat exchanger to convert another loop of water to steam, which drives the turbine. The advantage to this design is that the radioactive water/steam never contacts the turbine. Also, in some reactors, the coolant fluid in contact with the reactor core is gas (carbon dioxide) or liquid metal (sodium, potassium); these types of reactors allow the core to be operated at higher temperatures.
Given all the radioactive elements inside a nuclear power plant, it shouldn 't come as a surprise that there 's a little more to a plant 's outside than you 'd find at a coal power plant. In the next section, we 'll explore the various protective barriers between you and the atomic heart of the plant.

Nuclear Fission: The Heart of the Reactor
Despite all the cosmic energy that the word "nuclear" invokes, power plants that depend on atomic energy don 't operate that differently from a typical coal-burning power plant. Both heat water into pressurized steam, which drives a turbine generator. The key difference between the two plants is the method of heating the water.
While older plants burn fossil fuels, nuclear plants depend on the heat that occurs during nuclear fission, when one atom splits into two and releases energy. Nuclear fission happens naturally every day. Uranium, for example, constantly undergoes spontaneous fission at a very slow rate. This is why the element emits radiation, and why it 's a natural choice for the induced fission that nuclear power plants require.
Uranium is a common element on Earth and has existed since the planet formed. While there are several varieties of uranium, uranium-235 (U-235) is the one most important to the production of both nuclear power and nuclear bombs.
U-235 decays naturally by alpha radiation: It throws off an alpha particle, or two neutrons and two protons bound together. It 's also one of the few elements that can undergo induced fission. Fire a free neutron into a U-235 nucleus and the nucleus will absorb the neutron, become unstable and split immediately.

Outside The Nuclear Power Plant
Once you get past the reactor itself, there 's very little difference between a nuclear power plant and a coal-fired or oil-fired power plant, except for the source of th­e heat used to create steam. But as that source can emit harmful levels of radiation, extra precautions are required.
A concrete liner typically houses the reactor 's pressure vessel and acts as a radiation shield. That liner, in turn, is housed within a much larger steel containment vessel. This vessel contains the reactor core, as well as the equipment plant workers use to refuel and maintain the reactor. The steel containment vessel serves as a barrier to prevent leakage of any radioactive gases or fluids from the plant.
An outer concrete building serves as the final layer, protecting the steel containment vessel. This concrete structure is designed to be strong enough to survive the kind of massive damage that might result from earthquakes or a crashing jet airliner. These secondary containment structures are necessary to prevent the escape of radiation/radioactive steam in the event of an accident. The absence of secondary containment structures in Russian nuclear power plants allowed radioactive material to escape in Chernobyl.
Workers in the control room at the nuclear power plant can monitor the nuclear reactor and take action if something goes wrong. Nuclear facilities also typically feature security perimeters and added personnel to help protect sensitive materials.
As you probably know, nuclear power has its share of critics, as well as its supporters. On the next page, we 'll take a quick look at some of the pros and cons of splitting an ­atom to keep everyone 's TVs and toasters running.

BENEFITS OF NUCLEAR POWER STATIONS
Nuclear plants help regions meet air pollution standards. Air pollution compliance regulations are actually being enforced against the total supply of electricity, not just facilities that emit pollutants. A state or region can more easily remain within its emission limitations and still meet its energy needs when emission-free sources are used to satisfy a portion of demand.

Nuclear power also provides water quality and aquatic life conservation. Water discharged from a nuclear power plant contains no harmful pollutants and meets regulatory standards for temperature designed to protect aquatic life. This water, used for cooling, never comes in contact with radioactive materials. If the water from the plant is so warm that it may harm marine life, it is cooled before it is discharged to its source river, lake, or bay as it is either mixed with water in a cooling pond or pumped through a cooling tower.

Nuclear power plants provide low-cost, predictable power at stable prices and are essential in maintaining the reliability of the U.S. electric power system. Nuclear power is a major national energy source. Nuclear energy is our nation 's largest source of emission-free electricity and our second largest source of power. The 103 U.S. nuclear units supply about 20 percent of the electricity produced in the United States. The only fuel source that produced more electricity was coal.

The initial cost of a nuclear plant is very high, but within the lifetime the costs saved by the use of nuclear power rather than say oil or coal will have paid itself off. Also, speaking of coal and oil, the amount of harmful emissions released into our atmosphere is very large compared to the amount released by a nuclear power plant.

DRAWBACKS OF NUCLEAR POWER STATIONS
The waste produced by nuclear reactors needs to be disposed off at a safe place since they are extremely hazardous and can leak radiations if not stored properly. Such kind of waste emits radiations from tens to hundreds of years. The storage of radioactive waste has been major bottleneck for the expansion of nuclear programs. The nuclear wastes contain radio isotopes with long half-lives. This means that the radio isotopes stay in the atmosphere in some form or the other. These reactive radicals make the sand or the water contaminated.

While so many new technologies have been put in place to make sure that such disaster don’t happen again like the ones Chernobyl or more recently Fukushima but the risk associated with them are relatively high. Even small radiation leaks can cause devastating effects. Some of the symptoms include nausea, vomiting, diarrhea and fatigue. People who work at nuclear power plants and live near those areas are at high risk of facing nuclear radiations, if it happens.

There are power reactors called breeders. They produce plutonium. It is an element which is not found in the nature however it is a fissionable element. It is a by-product of the chain reaction and is very harmful if introduced in the nature. It is primarily used to produce nuclear weapons. Most likely, it is named as dirty bomb.

Another practical disadvantage of using nuclear energy is that it needs a lot of investment to set up a nuclear power station. It is not always possible by the developing countries to afford such a costly source of alternative energy. Nuclear power plants normally take 5-10 years to construct as there are several legal formalities to be completed and mostly it is opposed by the people who live nearby.

A CASE STUDY ON THE KOODANKULAM NUCLEAR POWER PLANT
Introduction
India has developed an installed capacity of 5,340 MW from wind power just over the last decade compared to 3580 MW from nuclear power developed over the last five decades. Nuclear power is expensive and dangerous. Its raw material is in short supply, as a result of which India is forced to sign a deal with the US, and scientists have no idea how to dispose off its radioactive waste. Wind power is dependent on naturally flowing wind which is in abundant supply available for free and doesn’t generate any regular waste. That is probably why the Koodankulam nuclear power plant has installed eight wind mills inside its premises. The deal, which does not have approval of the Indian parliament is not in the interest of people of this country and must be rejected. India must implement strict international safeguards in handling nuclear technology and materials and must develop an environment friendly power programme based on renewable resources. India has enough potential in solar and wind energy.

History of Koodankulam Nuclear Power Plant In 1988, during Rajiv Gandhi period a MOU (Memorandum of Understanding) for construction of nuclear power plant in India was signed between two countries India and Soviet (Russia). But due to several factors from political and economic crisis the project has been put on hold since there was a breakup in soviet and moreover with the objection from US stating that the agreement signed didn 't meet up with the current Terms and Conditions from the group of nuclear suppliers. Previously before 2004 the water reactor equipment was brought through roads as their mode of transport from Tuticorin port and due to various difficulties of damages incurred during its transportation it decided to select a Naval point base and come up with an idea to develop a small port near the tip of the country and they felt the best place would be Koodankulam in southern part of Tamil Nadu and then a small port become operational on January 14, 2004 and the main purpose of its construction is to receive baggage 's carrying oversized light water reactor from ships anchored at a few distance of half a km from its port. In 2007 a MOU was signed between India and Russia and when Russian president Vladimir Putin visited India he had discussion with Manmohan Singh and both countries have planned to promote the use of nuclear energy to certain heights.

Reasons behind the need for Koodankulam Nuclear Power Project
1. More than 1 million people live within the 30 km radius of the KNPP which far exceeds the AERB (Atomic Energy Regulatory Board) stipulations. It is quite impossible to evacuate this many people quickly and efficiently in case of a nuclear disaster at Koodankulam.

2. The quality of construction and the pipe work and the overall integrity of the
KNPP structures have been called into question by the very workers and contractors who work there in Koodankulam. There have been international concerns about the design, structure and workings of the untested Russian-made
VVER-1000 reactors.

3. The then Minister of State in the Ministry of Environment and Forest Mr.Jairam
Ramesh announced a few months ago that the central government had decided not to give permission to KNPP 3-6 as they were violating the Coastal Regulation
Zone stipulations. It is pertinent to ask if KNPP 1 and 2 are not violating the CRZ terms. 4. Many political leaders and bureaucrats try to reassure us that there would be no natural disasters in the Koodankulam area. How can they know? How can anyone ever know? The 2004 December tsunami did flood the KNPP installations. There was a mild tremor in the surrounding villages of Koodankulam on March 19,
2006. On August 12, 2011, there were tremors in 7 districts of Tamil Nadu.

CONCLUSION

Today Nuclear power effects, in one way or another, a small majority of us all. Through the process of nuclear fission we have electricity, smoke detectors, nuclear submarines, nuclear bombs, and much more. Plus with the production costs of nuclear energy being so much more reasonable it makes everything just that much easier for us all. Certainly nuclear power is not something to just mess around with because it can and will turn on you in an instant, but with evolving technology and understanding we will someday be able to tame to great power of nuclear fission to the point where we may be able to use it in everyday life.

REFERENCES

1. Petrucci, Ralph H., et al. “Nuclear Reactors.” General Chemistry: Principles & Modern Applications. New Jersey: Pearson Education, Inc, 2007. 1057-1058.
2. Bloomfield, Louis A. How Things Work: The Physics of Everyday Life, Second Edition. New York: John Wiley&Sons Inc, 2001. 445.
3. AJ Software & Multimedia. Nuclear Fission: Basics. 1998-2008. . United States Nuclear Regulatory Commission. Backgrounder on the Three Mile Island Accident. 11 August 2009. 29 November 2009 .
4. World Nuclear Association. Chernobyl Accident. November 2009. 2009 November 2009 .
5. International Thermonuclear Experimental Reactor (ITER). "What is Fusion?" November 22 2010. Web. 26 May 2011.
6. Nuclear Power Education. "Everything You Want to Know about Nuclear Power." September 3 2010. Web. 26 May 2011.

References: 1. Petrucci, Ralph H., et al. “Nuclear Reactors.” General Chemistry: Principles & Modern Applications. New Jersey: Pearson Education, Inc, 2007. 1057-1058. 2. Bloomfield, Louis A. How Things Work: The Physics of Everyday Life, Second Edition. New York: John Wiley&Sons Inc, 2001. 445. 3. AJ Software & Multimedia. Nuclear Fission: Basics. 1998-2008. . United States Nuclear Regulatory Commission. Backgrounder on the Three Mile Island Accident. 11 August 2009. 29 November 2009 . 4. World Nuclear Association. Chernobyl Accident. November 2009. 2009 November 2009 . 5. International Thermonuclear Experimental Reactor (ITER). "What is Fusion?" November 22 2010. Web. 26 May 2011. 6. Nuclear Power Education. "Everything You Want to Know about Nuclear Power." September 3 2010. Web. 26 May 2011.