Nuclear Power Industry
Nuclear Power Industry
a branch of the energy industry that uses nuclear energy (atomic energy) to produce electric power and heat and that is engaged in the development and practical use of methods and means of converting nuclear energy to heat and electricity. The basis of the nuclear power industry is the nuclear power plant, whose energy source is the nuclear reactor, in which the nuclei of heavy elements, chiefly 235U and 239Pu, undergo a controlled nuclear fission chain reaction. Upon the fission of uranium and plutonium nuclei, thermal energy is released, which is then converted to electric energy in the same way as in thermal steam-turbine power plants.
As man exhausts the reserves of fossil fuel—coal, petroleum, gas, and peat—the use of nuclear fuel, thus far, seems to be the only realistic alternative for providing the energy man needs. Because of the growing consumption and production of electric energy, some countries have already begun to experience shortages of fossil fuel, and increasingly developed countries are becoming dependent on imported energy resources. The depletion or shortage of fuel resources and the rising costs of extracting and transporting them were partially responsible for the energy crisis of the 1970’s. Therefore, intensive research is under way in some countries to develop new, highly efficient methods of producing electricity using other sources, first and foremost, nuclear energy.
No other branch of technology has developed as rapidly as the nuclear power industry, the world’s first nuclear power plant went into operation in 1954 in the city of Obninsk (USSR), and by 1978 there were more than 200 nuclear power plants, with a total installed capacity exceeding 100 gigawatts (GW), producing electricity in the USSR, the United States, Great Britain, France, Canada, Italy, the Federal Republic of Germany, Japan, Sweden, the German Democratic Republic, Czechoslovakia, Bulgaria, Switzerland, Spain, India, Pakistan, Argentina, and other countries. The proportion of nuclear power in the overall production of electricity is continuously growing, and, according to some predictions, by the year 2000 at least 40 percent of all electricity will be generated by nuclear power plants. The Soviet energy industry also calls for the intensive development of nuclear power, especially in the European part of the USSR.
All nuclear power plants make use of one of two types of reactors: thermal reactors or fast reactors. Thermal reactors are the simpler type and have been used extensively throughout the world, including the USSR. By the time the first nuclear power plant was developed in the USSR, the physical principles of the fission chain reaction of uranium nuclei in thermal reactors had already been worked out. The reactor selected was a heterogeneous uranium-fueled, graphite-moderated channel-type reactor with ordinary water as the coolant (seeREACTOR COOLANT). Such a reactor is reliable and provides a high degree of safety, particularly through the compartmentalization of the circulation coolant loop, and it can be refueled while it is in operation. The thermal power of the reactor in the first nuclear power plant was 30 megawatts (MW), and the rated electric power, 5 MW. The start-up of the Obninsk plant proved the feasibility of utilizing the new energy source, and the experience gained in constructing and operating the plant has been applied in the construction of other nuclear plants in the USSR.
The I. V. Kurchatov Beloiarsk Atomic Power Plant went online within the Sverdlovsk power system in 1964. Its thermal reactor, with an electrical output of 10 MW, differed considerably from its predecessor: it had higher thermal characteristics as a result of the superheating of steam in the reactor core (core superheating). A second unit of improved design and higher power output (200 MW) was started up at the Beloiarsk Atomic Power Plant in 1967; the reactor has a single-loop cooling system. The principal disadvantage of core superheating is the increased temperature in the reactor core, which necessitates the use of heat-resistant materials, like stainless steel, for the fuel cladding; in most cases, this results in decreased overall efficiency of utilization of nuclear fuel (seeFUEL ELEMENT).
The uranium-fueled, graphite-moderated channel-type reactors used in the early power plants are not encased within a heavy, awkward steel vessel. The construction of nuclear power plants with such reactors is rather enticing, since it frees heavy-machine-building plants from the production of huge steel vessels, weighing 200–500 tons (the vessel of a water-moderated water-cooled reactor is shaped like a cylinder, measuring 3–5 m in diameter and 11–13 m in height and having a wall thickness of 100–250 mm). Operating experience with early uranium-graphite reactors, with a single-loop system using boiling water as the coolant, led to the development of the RBMK reactor in the USSR, a single-loop high-power uranium-fueled, graphite-moderated boiling-water reactor (seeBOILING-WATER REACTOR). The first such reactor, with an electrical output of 1,000 MW (the RBMK-1000), was installed in September 1973 at the Lenin Nuclear Power Plant in Leningrad, and in December 1973 the plant’s first unit began supplying electricity to the Lenenergo power system. A second unit, also with an electrical output of 1,000 MW, was started up in late 1975. In 1977 the Lenin Nuclear Power Plant produced 12.5 billion kilowatt-hours (kW-hr) of electricity. Construction of the Lenin Plant is continuing, and it will eventually consist of four units, with a total electrical output of 4,000 MW. The thermal power of each unit is 3,200 MW; 70 gigacalories per hour (Gcal/hr), or 335 gigajoules per hour (GJ/hr), of heat will be used for central heating purposes. The Lenin Nuclear Power Plant is the principal nuclear plant in the European part of the USSR.
The first unit of the Kursk Nuclear Power Plant, with an RBMK reactor with an electrical output of 1,000 MW, went into operation in 1976, and the Chernobyl’ Nuclear Power Plant was started up in 1977. Construction is nearing completion on the Smolensk Nuclear Power Plant and other plants, also with several RBMK-1000 reactors. In 1975 construction was begun in the Lithuanian SSR on the Ignalina Nuclear Power Plant, with four uranium-fueled, graphite-moderated channel-type reactors, each with an electrical output of 1,500 MW. A power increase to 1,500 MW has actually been achieved in the RBMK-1000 reactor at the Ignalina Plant by means of various design improvements, mainly the design of the fuel elements. The power boost of the RBMK-1000 has reduced specific capital investments in the construction of the nuclear power plant and has raised its average specific power. Work is under way (1978) to develop RBMK-type reactors with electrical outputs of 2,000 and 2,400 MW.
A nuclear district heat and power plant has been operating successfully since 1974 in the USSR near the city of Bilibino, Magadan Oblast. The electrical output of the Bilibino Plant is 48 MW, and 100 Gcal/hr of heat is generated for district heat supply and centralized hot-water supply.
Shell-type water-moderated water-cooled reactors (designated VVER in the USSR) are the most extensively used thermal reactors in the USSR (seeWATER-MODERATED WATER-COOLED REACTOR). In 1964 the Novovoronezhskii Atomic Power Plant went into operation, with a water-moderated water-cooled reactor having an electrical output of 210 MW and in which ordinary water serves as both the moderator and the coolant. The thermal power of the reactor is 760 MW. The reactor is one of the best reactors with respect to specific energy-release rate and economy of fuel utilization. In December 1969 the second unit was started up, with a water-moderated water-cooled reactor having an electrical output of 365 MW. In 1971–72 the third and fourth units were started up, each with an electrical output of 440 MW using VVER-440 reactors. In 1977 the Novovoronezhskii Atomic Power Plant produced more than 10 billion kW-hr of electricity. With the completion of the fifth unit in 1978, with an electrical output of 1,000 MW, the capacity of the Novovoronezhskii Plant rose to 2,500 MW. It is precisely this fifth unit, with the VVER-1000, that has become the prototype of nuclear power plants now under construction with high-power water-moderated water-cooled reactors.
The gradual increase in the unit power of the energy-generation equipment at the Novovoronezhskii Nuclear Plant (210,365, 440, and 1,000 MW) is typical not only of water-moderated water-cooled reactors. The development of the energy industry, including the nuclear power industry, throughout the world has been accompanied by a rise in the unit power of energy-generation facilities. The increase of equipment size brings about some reduction in the construction costs of nuclear power plants; however, each succeeding stage of enlargement is accompanied by less savings. Two units of a nuclear power plant, each with a VVER-440 reactor, were put into operation on the Kola Peninsula in 1973–74. The start-up of the Kola Nuclear Power Plant is important, since the Kola Peninsula is poor in hydroelectric resources and it is not economically feasible to bring in fuel from elsewhere.
In the Armenian SSR, the first unit of a nuclear power plant with a VVER-440 reactor was started up in December 1976. The plant, the first nuclear power plant in Armenia and Transcaucasia, is situated in the mountains at an elevation of 1,100 m above sea level in an earthquake region. This siting of the Armenian Nuclear Power Plant implies a solution for the problem of ensuring reliable and safe operation of nuclear power plants under difficult seismic conditions. According to calculations, the plant should be able to withstand underground shocks of 8–9 points (in the autumn of 1976 it withstood a shock of 4–5 points during an earthquake in Turkey.)
The USSR is providing technical assistance to a number of socialist countries in the construction of nuclear power plants with water-moderated water-cooled reactors. For example, a nuclear power plant was constructed in 1966 in the city of Rheinberg in the German Democratic Republic, with a 70-MW water-moderated water-cooled reactor. Three units, with VVER-440 reactors, were put into operation in the period 1973–77 at the Bruno Leuschner Nuclear Power Plant on the Baltic, and the construction of three more units is successfully continuing. Two units, with VVER-440 reactors, have been in operation at the Kozlodui Nuclear Power Plant in Bulgaria since 1976, and construction is nearly complete on two more units with the same power rating. The A-l Nuclear Power Plant is Czechoslovakia has been in operation since 1972, with a reactor moderated by heavy water and cooled by CO2 and having an electrical output of 140 MW. The reactor was developed by the joint efforts of Soviet and Czech specialists. A large industrial nuclear power plant, with a VVER-440 reactor, has been recently completed in Czechoslovakia; the first unit went into operation in 1978, and the second in 1979. Nuclear power plants with VVER-440 reactors are being built in Rumania, Hungary and Poland. Construction of a nuclear power plant with a VVER-440 reactor was completed with Soviet technical assistance in Finland in 1976. Experience gained in building and operating water-moderated water-cooled reactors in the USSR and elsewhere has led to the development of a four-loop VVER-1000 reactor, in which each loop, with a thermal power of 750 MW, contains a steam generator, a main circulating pump, two shutoff valves, and other equipment.
In addition to pressurized-water reactors, a boiling-water reactor has been developed in the USSR with a single-loop arrangement for the direct production of steam within the reactor itself. An experimental nuclear power plant with a VK-50 boiling-water reactor (50 MW) was constructed in Dimitrovgrad, Ul’ianovsk Oblast, and started up in 1965. The single-loop arrangement considerably simplifies the heat-generation equipment and simplifies the connection of the nuclear reactor to the turbogenerator. The plant with the VK-50 reactor has proved reliable and very safe to operate.
Many different types of thermal reactors using various moderators and coolants have been built throughout the world. Among these are pressurized-water reactors; boiling-water reactors; uranium-fueled, graphite-moderated, water-cooled reactors; uranium-fueled, graphite-moderated reactors with core superheating; organic-cooled reactors with organic moderator and coolant; high-temperature gas-cooled reactors with carbon dioxide as the coolant and graphite as the moderator; heavy-water-moderated reactors with ordinary water as the coolant; heavy-water reactors with heavy water as both the moderator and coolant; and helium-cooled reactors.
It has been established that nuclear power plants with thermal reactors can compete successfully with conventional fossil-fuel-fired power plants; however, such nuclear plants are not being developed in great number owing to the low efficiency with which thermal reactors utilize natural uranium. There is a better outlook for fast reactors, which make use of fast neutrons and thus can make the best possible use of the fissioning of the nuclei of heavy elements and simultaneously produce a new artificial nuclear fuel, 239Pu. When fast neutrons enter the 238U nucleus, there are several conversion reactions and some transuranium elements are produced, resulting in the formation of 239Pu. When 239Pu nuclei fission, more neutrons are liberated than during the fission of 235U. If nuclear power is considered from the standpoint of the efficient use of nuclear fuel, then the main task of the nuclear power industry is to choose methods for the optimum use of neutrons and to reduce wasteful losses of neutrons produced upon the fission of uranium and plutonium nuclei. The breeding, or conversion, ratio in fast reactors may reach 1.4 and even 1.7; that is, in “burning” 1 kg of plutonium, a fast reactor not only recovers it but, by incorporating nonfissile isotopes of 238U in the fuel cycle, gains an additional 0.4–0.7 kg of plutonium that can serve as new nuclear fuel.
Construction was completed in 1968 in the city of Dimi-trovgrad of a large 12-MW research nuclear power plant with a BOR-60 fast reactor. The reactor enabled Soviet scientists to work on improving the performance and design of individual elements of the sodium-cooled fast reactor and confirmed the correctness of the path taken by Soviet scientists to develop fast power reactors. A large experimental nuclear power plant with a BN-350 sodium-cooled fast reactor was built in late 1972 on the Mangyshlak Peninsula; it is a dual-purpose facility that will both produce electric energy (installed capacity of 150 MW) and generate steam for desalinization units, which will produce 120,000 tons of fresh water from seawater per day. The Shevchenko Nuclear Power Plant, the largest experimental-industrial power facility with fast reactors in the world (as of 1978), is helping scientists solve a number of problems in the production of nuclear power. The third unit now under construction at the Beloiarsk Atomic Power Plant is equipped with a fast reactor with an electrical output of 600 MW (BN-600). The construction and start-up of a nuclear power plant with a BN-600 reactor constitute the next stage in the development of the Soviet nuclear power industry. The BN-600 uses the integral configuration of the in-pile loop, a new design that operates more economically than the BN-350. In this arrangement, the reactor core, pumps, and intermediate heat exchangers are all housed within a single vessel. A comparison of the operation of the BN-350 and the BN-600 will eventually show which design and engineering solutions are superior.
One of the main goals of fast-reactor research is to achieve the rapid breeding of nuclear fuel, which is impossible in other types of reactors. Scientific research and experiments are continuing to develop liquid-metal-cooled fast reactors with greater power output, ranging from 800 to 1,600 MW. The United States, Great Britain, France, and other countries are also working on sodium-cooled fast reactors. However, sodium is not the only coolant that can be used in fast reactors. Gas, particularly helium, can also be used, and research on the use of N2O4 gas as a coolant is being conducted at the Institute of Nuclear Power Engineering of the Academy of Sciences of the Byelorussian SSR.
In the early stages of the development of the nuclear power industry, scientists in many countries worked on a number of different reactors with the goal of selecting the optimum one from the standpoint of engineering and economics. In the 1970’s most countries decided to concentrate the efforts of their national reactor programs toward developing a limited number of reactor types. For example, the major emphasis is on pressurized-water and boiling-water reactors in the United States, the heavy-water-moderated reactor using natural uranium in Canada, and pressurized-water and uranium-fueled, graphite-moderated channel-type reactors in the USSR.
In view of the substantial increases in the cost of coal and especially petroleum and the ever-growing-difficulties of recovering these resources, the rapid development of the nuclear power industry is coming to be completely justified from the economic standpoint. According to present estimates, the cost of producing electric energy in a nuclear power plant is 1.5–2 times less than in conventional fossil-fuel-fired plants. According to forecasts by non-Soviet specialists, about 250 reactors with a total power of 200 gigawatts (GW) were to be in operation worldwide by 1980. Although economic crises in capitalist countries and other attending circumstances may alter this forecast and the figures may prove to be lower, the general tendency toward growth of the nuclear power industry is obvious. The use of nuclear energy to generate electricity, produce heat, desalinate water, produce reducing agents for the metallurgical industry, and synthesize new types of chemical goods are all tasks of an enormous scale that not only impart new qualities to the nuclear power industry but also reveal new possibilities for the use of nuclear energy. Another advantage of nuclear energy is that nuclear power plants do not pollute the air with oxides of sulfur and nitrogen, which adversely affect the environment. A great deal of attention is being given in the USSR and other industrially developed countries to the problem of protecting the population from radiation hazards and the environment from radioactive contamination.
In addition to large industrial facilities, the USSR is currently developing and building special-purpose nuclear power plants of small and very small power capacity. The TES-3 mobile nuclear power plant, with a water-moderated water-cooled reactor and an electrical output of 1,500 kW, was put into operation in 1961. All its equipment is accommodated on four self-propelled caterpillar truck platforms with wagon-type bodies.
The 500-W Romashka installation, with a fast reactor and semiconductor thermoelectric converters, was put into operation in 1964. It worked for more than 15,000 hours in bench-scale testing instead of the anticipated 1,000 hours. The Romashka is the prototype of a nuclear facility providing for the direct conversion of nuclear energy to electricity.
The Topaz-1 and Topaz-2 thermionic converter (or regenerative) reactors, with electrical outputs of 5 and 10 kW, respectively, were built and tested in 1970–71. The principle of the direct conversion of thermal energy to electricity consists in heating the cathode to a high temperature in a vacuum while keeping the anode relatively cool, in the course of which electrons are “evaporated” (emitted) from the cathode surface and, after crossing the interelectrode space, “condense” on the anode, producing an electric current in a closed external circuit. The principal advantage of such a facility over generator dynamos is the absence of moving parts. Power plants based on the use of nuclear energy are also finding application as propulsion units. Such units are particularly widely used on submarines, as well as on nonmilitary transport vessels, including atomic icebreakers.
During the operation of a nuclear power plant, considerable amounts of liquid and solid radioactive wastes are formed. The liquid wastes at a nuclear power plant include the discarded coolant of the in-pile loop (in the event it is changed), any leakage of coolant when the integrity of equipment fails, the water in reservoirs where spent fuel elements are stored, decontamination solutions, solutions from the reprocessing of ion-exchange filters, laundry water from protective clothing, and water from decontamination stations for equipment and special transportation. Practice has shown that 0.5 to 1.5 cu m of moderately radioactive liquid waste are formed per 1 MW of electrical output produced by a reactor in a year of nuclear plant operation. Liquid wastes with a moderate radioactive level contain about 99 percent of waste radionuclides.
In the USSR all liquid radioactive wastes are processed directly at nuclear power plants using methods of evaporation and ion exchange. The waste concentrates (vat residues after evaporation), ion-exchange resins, slurries, and used primary coolant are collected and sent through sealed ducts to special storage tanks for intermediate-level wastes.
The solid radioactive wastes at a nuclear power plant are mainly individual components or subassemblies of reactor equipment, tools, protective clothing, personnel shielding devices, rags, and filters from gas purification systems. In addition to liquid and solid radioactive wastes, volatile compounds of radioactive isotopes may be emitted and radioactive aerosols may be formed. Certain amounts of radioactive gases and aerosols are released into the atmosphere after special purification, and liquid and solid wastes contaminated with radioactive materials are deposited in special burial grounds.
However, the major problem of the nuclear power industry is the development of economic, reliable methods of disposing of large amounts of high-level wastes. Research and development is under way in this area in many countries, especially in developing effective methods for the vitrification of radioactive wastes. In the 1970’s, the processing of spent fuel elements was still not extensively developed, but with the increased construction of nuclear power plants and especially of fast reactors, where a large amount of secondary nuclear fuel is needed, the burial of high-level wastes may become of primary importance.
The United Nations International Atomic Energy Agency (IAEA) has recommended that low-level and intermediate-level radioactive wastes be discharged into the northeastern part of the Atlantic. Containers capable of holding nearly 40,000 tons of wastes with about 240,000 curies of beta and gamma radioactivity were discharged into the ocean in 1976. However, this method for the disposal of radioactive wastes in the depths of the seas and oceans has evoked protests from scientists in a number of countries.
One of the most important problems of the nuclear power industry is the problem of generating energy by controlled nuclear fusion. With the development of a nuclear fusion power reactor, all the problems of the nuclear power industry will be solved with respect to the collection and disposal of high-level radioactive wastes. By 1977, several fusion facilities had produced neutrons of thermonuclear origin. At the present time, the most advanced system is the Tokamak, developed in the 1950’s at the I. V. Kurchatov Institute of Atomic Energy in Moscow. The Tokamak-10, the largest thermonuclear facility in the world, was started up at the institute in 1977. The Tokamak system has received recognition in a number of leading countries. For example, the Princeton Large Tokamak (PLT) has been set up at Princeton University in the United States, and the Tokamak Fontenay Rose (TFR) has been built at the Nuclear Research Center in Fontenay-aux-Roses, France. The attainment of controlled thermonuclear fusion, which would provide a virtually inexhaustible supply of energy in thermonuclear power plants, is the most important problem of nuclear physics, a task of enormous scale being worked on today by scientists in various fields in many countries.
REFERENCESAleksandrov, A. P. “Atomnaia energetika i nauchno-tekhnicheskii progress.” In the collection Atomnoi energetike XX let. Moscow, 1974.
Margulova, T. Kh. Atomnye elektricheskie stantsii, 2nd ed. Moscow, 1974.
Petros’iants, A. M. Sovremennye problemy atomnoi nauki i tekhniki v SSSR, 3rd ed. Moscow, 1976.
A. M. PETROSIANTS