Воробева Нуцлеар Реацтор Тыпес (Леарн то реад бы реадинг) 2010
.pdfNOTE: 1/3 of this comes from plutonium! Plutonium is а great fuel (but does require careful handling under proper conditions).
•World -17 % of world electricity now from nuclear Hence, 6 % of world's electricity comes from Pu;
•Smokeless, odorless — environmentally friendly;
•Waste problem an intrinsic advantage:
•Plutonium has long-term importance.
-It can literally last а millennium.
2)Power production assures stable economy and stable social
structure:
•Energy creates wealth;
•Wealth creates health.
В) Problems (most are emotional failures to accept reality):
1)Short Term:
•International Tensions Over Proliferation: - fundamental anti-nuclear argument.
2)Life Threatening:
•Bombs:
- Of course, Pu or U are good fuels for bombs (even though "reactor grade" fuels for such purposes have been greatly overplayed);
•Toxicity:
- The charge that Pu is the most toxic substance now to man (we'll return to this!);
3)Long Term:
•24,000 year half-life;
•storage Issues:
-it seems to be the long-term implications of radioactivity that form the crux of people's fear.
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С) Some say BAN PLUTONIUM. D) Why not ban?
•Compared to alternate fuel for producing electricity, it is
very clean
•It could be absolutely essential for sustainable life on our
planet
•I know of no other possible long-term fuel (other than possibly thorium or tritium)
IV) PROBLEMS OF SEX AND PLUTONIUM IN PERSPECTIVE
А) Problems of sex are real; not imagined.
В) Problems of Plutonium: (partially real, but more commonly imaginary):
1)Proliferation:
•Despite а11 the rhetoric, there are 36 nations with nuclear energy, but only б confirmed nuclear weapons states.
Very few nations are willing to pay the price as long as they can gain access to the things they really need (like energy).
2)Bombs (how can they be acquired?):
•National — Dedicated effort, requiring а major commitment to expensive facilities and skilled personnel;
•Sub-national (terrorist groups):
-Acquiring а bomb would certainly provide them with enormous political power;
-But how are they going to get it?
•Build (acquire fue1, assemble weapon, deliver it). HUGE PROBLEMS!!!
•Stealing an already built weapon far more in line with inherent strengths of terrorist groups:
-types of bombs actual terrorists employ: а11 were simple chemical bombs.
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3)Toxicity
•"Plutonium is the most toxic substance known to mankind" (!!!) where did this "common knowledge" arise?
•Toxicity only а problem if inhaled:
-even here, 10,000 pounds of Pu released into the atmosphere as aerosol during atmospheric nuclear weapons testing up to middle of 1960's. NO deaths attributable!
•If swallowed:
-Lead arsenate 10 times more toxic than Pu — Botulism 1 million — Anthrax spores 10 million
А) Of course we will never ban sex:
• We could not, should not; it's an inescapable reality; it is needed for survival!
В) Likewise, we can not, should not even consider banning plutonium; it is an inescapable reality - it exists, and for good reason:
1) World needs electricity
To deny plutonium as а possible solution is an ethical matter of immense proportions!
С) World without nuclear power.
VI) CONCLUSION
1)Sex and Pu both exceptional powerful commodities. Both need careful control.
2)Both essential for maintaining and satisfying life on earth.
3)Given appropriate controls, and appropriate understanding, these are two of the most precious, life-enhancing gifts we have ever been given.
4)Our job: Knowledge and control NOT Ignorance and abuse.
IT IS UP ТО US, if we are to survive and thrive in the 21st century!
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READING 12-D
Military Warheads as a Source of Nuclear Fuel
For more than three decades concern has centered on the possibility that uranium intended for commercial nuclear power might be diverted for use in weapons. Today, however, attention is focused on the role of military uranium as a major source of fuel for commercial nuclear power.
Since 1987 the United States and countries of the former USSR have signed a series of disarmament treaties to reduce the nuclear arsenals by about 80 %.
Nuclear materials declared surplus to military requirements by the USA and Russia are now being converted into fuel for commercial nuclear reactors. The main material is highly enriched uranium (HEU), containing at least 20 % uranium-235 (U-235) and usually about 90 % U-235. HEU can be blended down with uranium containing low levels of U-235 to produce low enriched uranium (LEU), typically less than 5 % U-235, fuel for power reactors. It is blended with depleted uranium (mostly U-238), natural uranium (0.7 % U-235), or partially-enriched uranium.
Highly-enriched uranium in US and Russian weapons and other military stockpiles amounts to about 2000 tonnes, equivalent to about twelve times annual world mine production.
World stockpiles of weapons-grade plutonium are reported to be some 260 tonnes, which if used in mixed oxide fuel in conventional reactors would be equivalent to a little over one year's world uranium production. Military plutonium can blended with uranium oxide to form mixed oxide (MOX) fuel.
After LEU or MOX is burned in power reactors, the spent fuel is not suitable for weapons manufacture.
Megatons to Megawatts
Commitments by the US and Russia to convert nuclear weapons into fuel for electricity production is known as the Megatons to Megawatts program.
13 000 nuclear warheads have been claimed to be eliminated.
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READING 12-E
• Scan the text 5 minutes) and tell it in your language.
Novel uses of uranium.
Researchers have designed a molecule that can "eat" and then "trick" uranium into behaving like a lighter atom. The molecule, which is a "Pac-Man lookalike», could open the door for future developments in nuclear waste management or novel uses of uranium.
In solution, uranium forms the notoriously stable and highly watersoluble uranyl ion, in which uranium is bound to two atoms of oxygen. The incredible strength of the uranium-oxygen bonds make it very unreactive, and, coupled with its high solubility in water, makes it very difficult to remove from water in the environment.
Husband-and-wife team Jason Love and Polly Arnold, both scientists at the University of Edinburgh, have developed a macro cycle — imagine a piece of molecular scaffolding — which they say is shaped like Pac-Man videogame character of the 1980s. The macro-cycle grips the uranium and one of the oxygen atoms in its "mouth", leaving the other oxygen atom sticking out. The protruding oxygen atom can then be made to react with organic compounds in unusual new ways.
Although this sort of chemistry is common in enzymes and industrial catalysts using lighter metals, it is the first time it has been done with uranium. "We have found a way to trick uranium into behaving like a lighter metal," said Arnold. The macro-cycle, as it stands, is not sufficiently stable in water for it to be used to remove uranyl from solutions, but the discovery should have long-term benefits for nuclear research. The behavior of the "tricked" uranium might help environmental scientists discover new ways of removing uranium from contaminated water. It can also be used to help predict more accurately the behavior of uranium's more reactive relative plutonium.
Arnold is enthusiastic that the discovery can benefit future research, hoping that it may perhaps spark the imaginations of other scientists and help them to think differently about the chemical behaviour of uranium in the environment. "Anything we can do to challenge preconceptions of how such molecules behave helps in the long run," she told World Nuclear News, adding that the macrocycle-uranyl complex would provide a useful model for intermediates in more complex systems typical of those
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encountered in waste streams from the different stages of the nuclear fuel cycle from uranium mining through to spent fuel processing.
UNIT XIII
OTHER USES
Although this book focuses on the use of nuclear energy to produce electricity, it is important to note that nuclear energy is also used to produce many other useful products and services like fresh water, radioisotopes used in many parts of our modern world, with health services, industry and even domestic safety very dependent on them. Many homes have smoke detectors which depend on a tiny amount of americium, derived from plutonium made in a nuclear reactor. In the developed countries, about one half of all people will depend on nuclear medicine at some stage of their lives.
READING 13-A
Nuclear Desalination
Discuss the following:
•Potable water is in short supply in many parts of the world. Lack of it is set to become a constraint on development in some areas.
•Nuclear energy is already being used for desalination, and has the potential for much greater use.
•Nuclear desalination is generally cost-competitive with using fossil fuels.
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It is estimated that one fifth of the world's population does not have access to safe drinking water, and that this proportion will increase due to population growth relative to water resources. The worst-affected areas are the arid and semiarid regions of Asia and North Africa. Wars over access to water, not simply energy and mineral resources, are conceivable.
Fresh water is a major priority in sustainable development. Where it cannot be obtained from streams and aquifers, desalination of seawater or mineralized groundwater is required.
Desalination
Most desalination today uses fossil fuels, and thus contributes to increased levels of greenhouse gases. Total world capacity is approaching 30 million m³/day of potable water, in some 12 500 plants.
The major technology in use and being built today is reverse osmosis (RO) driven by electric pumps which force water through a membrane against its osmotic pressure. Multi-stage flash (MSF) distillation process using steam was earlier prominent and it is capable of using waste heat from power plants.
Desalination is energy-intensive. Reverse Osmosis needs about 4 — 6 kWh of electricity per cubic meter of water (depending on its salt content). A variety of low-temperature heat sources may be used, including solar energy.
The choice of process generally depends on the relative economic values of fresh water and particular fuels, and whether cogeneration is a possibility.
Some 10 % of Israel's water is desalinated, and one large RO plant provides water at 50 cents per cubic meter. Malta gets two thirds of its potable water from RO. Singapore in 2005 commissioned a large RO plant supplying 136,000 m³/day — 10 % of needs, at 49 cents US per cubic meter.
Small and medium sized nuclear reactors are suitable for desalination, often with cogeneration of electricity using low-pressure steam from the turbine and hot sea water feed from the final cooling system.
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READING 13-B
Desalination: nuclear experience
The feasibility of integrated nuclear desalination plants has been proven with over 150 reactor-years of experience, chiefly in Kazakhstan, India and Japan.
The BN-350 fast reactor at Aktau, in Kazakhstan, successfully produced up to 135 MWe of electricity and 80 000 m³/day of potable water over some 27 years, about 60 % of its power being used for heat and desalination. It is interesting to note that the first Rector of RF Nuclear University in Obninsk well known as IATE was the leader of the project and managed the physical start up of the BN-350.
In Japan, some ten desalination facilities linked to pressurized water reactors operating for electricity production have yielded 1000 — 3000 m³/day each of potable water, and over 100 reactor-years of experience have accrued. The water is used for the reactors' own cooling systems.
India has been engaged in desalination research since the 1970s Much relevant experience comes from nuclear plants in Russia, Eastern Europe and Canada where district heating is a by-product.
READING 13-C
New projects
South Korea has developed a small nuclear reactor design for cogeneration of 90 MWe of electricity and potable water at 40 000 m³/day.
Spain is building 20 RO plants in the southeast to supply over 1 % of the country's water.
In the UK, a 150 000 m³/day RO plant is proposed for the lower Thames estuary, utilizing brackish water.
In India plants delivering 45 000 m³ per day are envisaged, using both MSF and RO desalination technology.
China is looking at the feasibility of a nuclear seawater desalination plant producing 160 000 m³/day by MED process, using a 200 MWt reactor.
Russia has embarked on a nuclear desalination project using dual barge-mounted KLT-40 marine reactors (each 150 MWt) and Canadian RO technology to produce potable water.
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Pakistan is continuing efforts to set up a demonstration desalination plant coupled to its KANUPP reactor (125 MWe PHWR) producing 4500 m³/day.
Tunisia is looking at the feasibility of a cogeneration (electricitydesalination) plant in the southeast of the country, treating slightly saline groundwater.
Morocco has completed a pre-project study with China, using a 10 MWt heating reactor which produces 8000 m³/day of potable water by distillation (MED).
Egypt has launched a feasibility study of a cogeneration plant for electricity and potable water on the Mediterranean coast.
Argentina has also developed a small nuclear reactor design for cogeneration or desalination alone.
Most or all these have requested technical assistance from IAEA under its technical cooperation project on nuclear power and desalination. A coordinated research project initiated in 1998 reviewed reactor designs intended for coupling with desalination systems as well as advanced desalination technologies. Safety and reliability are key requirements. This program is expected to enable further cost reductions of nuclear desalination.
UNIT XIV
OTHER USES (CONTINUED)
Discuss the following:
Nuclear power is relevant to road transport and motor vehicles in three respects:
-Electric vehicles potentially use off-peak power from the grid for recharging.
-Nuclear heat can be used for production of liquid hydrocarbon fuels from coal.
-Hydrogen for oil refining and for fuel cell vehicles may be made electrolytically, and in the future, thermochemically using hightemperature reactors.
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READING 14-A
Other uses: Smoke Detectors
•Most smoke detectors which operate alarms contain an artificially produced radioisotope: americium-241.
•Americium-241 is made in nuclear reactors, and is a decay product of plutonium-241.
Smoke detectors / alarms are important safety devices, because of their obvious potential to save lives and property. There are two types of smoke detector commonly available in many countries.
One type uses the radiation from a small amount of radioactive material to detect the presence of smoke or heat sources. These "ion chamber smoke detectors" are the most popular, because they are inexpensive and are sensitive to a wider range of fire conditions than the other type.
The other type of detector does not contain radioactive material; it uses a photoelectric sensor to detect the change in light level caused by smoke. This type is more expensive to purchase and install, and is less effective.
The vital ingredient of household smoke detectors is a very small quantity (<35 kBq) of americium-241 (Am-241). This element was discovered in 1945 during the Manhattan Project in USA. The first sample of americium was produced by bombarding plutonium with neutrons in a nuclear reactor at the University of Chicago.
Americium is a silvery metal, which tarnishes slowly in air and is soluble in acid. Its atomic number is 95. Its most stable isotope, Am243, has a half-life of over 7500 years, although Am-241, with a halflife of 432 years, was the first isotope to be isolated.
Americium (in combination with beryllium) is also used as a neutron source in non-destructive testing of machinery and equipment, and as a thickness gauge in the glass industry. However, its most common application is as an ionization source in smoke detectors, and most of the several kilograms of americium made each year is used in this way.
Operation of Smoke Detectors
Americium-241 emits alpha particles and low energy gamma rays
(60 keV, giving a dose at 1 metre of 0.0011 mSv/yr). The alpha particles are absorbed within the detector, while most of the gamma rays escape harmlessly. The americium is present in oxide form in the detector.
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