Fission power

This reaction offers the advantage of a superior neutron yield of in a thermal reactor system. The abiHty to breed fissile from naturally occurring Th allows the world s thorium reserves to be added to its uranium reserves as a potential source of fission power. However, the Th/ U cycle is unlikely to be developed in the 1990s owing both to the more advanced state of the / Pu cycle and to the avadabiHty of uranium. Thorium is also used in the production of the cx-emitting radiotherapeutic agent, Bi, via the production of Th and subsequent decay through Ac (20). 

Zirconium carbide is a highly refractory compound with excellent properties but, unlike titanium carbide, it has found only limited industrial importance except as coating for atomic-fuel particles (thoria and urania) for nuclear-fission power plants.l " ] This lack of applications may be due to its high price and difficulty in obtaining it free of impurities. 

A few nations rely heavily on nuclear power despite the possibility of accidents. In France and Japan, fission power from nuclear reactors provides two thirds or more of overall energy needs. A French plant appears in Figure 22-14C. 

C22-0068. Describe the features of fusion that have prevented fusion power from being commercialized as fission power has been. 

C22-0130. List the advantages and disadvantages of fission power and fusion power. Based on your list, do you think that the United States should continue to develop fission power plants What about fusion power plants ... 

Nuclear fission power plants were at one time thought to be the answer to diminishing fossil fuels. Although the enriched uranium fuel was also limited, an advanced nuclear reactor called breeders would be able to produce more radioactive fuel, in the form of plutonium, than consumed. This would make plutonium fuel renewable. Although plutonium has been called one of the most toxic elements known, it is similar to other radioactive materials and requires careful handling since it can remain radioactive for thousands of years. 

It is highly improbable that a nuclear fission power plant would ever explode like a nuclear bomb, but a loss of coolant accident could result in a melt down condition. In a melt down, a large amount of radiation can be released at ground-level. A nuclear or conventional chemical or steam explosion could disperse much of the radioactive particles into the atmosphere. This is essentially what happened when the Chernobyl gas explosion occurred in the Soviet Union in 1986. 

Diagram of a nuclear fission power plant. Note that the water in contact with the fuel rods is completely contained and radioactive materials are not involved directly in the generation of electricity. The details of the production of electricity are covered in Chapter 19. 

One of the fascinating features of fission power is the breeding of fission fuel from nonfissionable uranium-238. Breeding occurs when small amounts of fissionable isotopes are mixed with uranium-238 in a reactor. Fission liberates neutrons that convert the relatively abundant nonfissionable uranium-238 to uranium-239, which beta-decays to neptunium-239, which in turn beta-decays to fissionable plutonium-239. So in addition to the abundant energy produced, fission fuel is bred from relatively abundant uranium-238 in the process. 

The benefits of fission power are plentiful electricity, conservation of many billions of tons of fossil fuels annually, and the elimination of the megatons of sulfur oxides and other poisons put into the air each year by the burning of fossil fuels. The drawbacks are the formation of massive quantities of radioactive wastes that require long-term safe storage. 

Is it possible for a nuclear fission power plant to blow up like an atomic bomb ... 

Nearly 443 nuclear fission power plants are in operation around the world, and of these, 103 are located in the United States (Figure 1.10). The American plants were built at a total investment of about 0.5 trillion. Plant construction takes over 10 years, and no new orders have been issued for nuclear power plants for decades. Between 1970 and 1980, some 100 applications were submitted, but all were turned down. During the last 50 years, 253 nuclear... 

All the components of the nuclear-fission power system are fully operational except for ultimate waste disposal. However, spent fuel is not reprocessed in the United States because there is currently an adequate supply of natural uranium and enrichment services availab 1 e domestically and from other countries at a 1 ower cost than that of the recovered fissionable material from spent fuel. Also, the United States unilaterally declared a moratorium on reprocessing in the early 1980s in an attempt to reduce the spread of nuclear weapons. Current economics do not favor a return to reprocessing and fuel recycling in the United States at this time in as much as it does dramatically increase the amount of interim and final waste storage capacity that is required. 

There is a trend in the United States toward using coal-fired power plants to generate electricity rather than building new nuclear fission power plants. Is the use of coal-fired power plants without risk Make a list of the risks to society from the use of each type of power plant. 

As with fission, scientists and nonscientists alike expressed hope that fusion reactions could someday be harnessed as a source of energy for everyday needs. This line of research has been much less successful, however, than research on fission power plants, hi essence, the problem has been to find a way of producing, in a controlled, sustainable fashion, the very high temperatures (millions of degrees Celsius) needed to sustain fusion. Optimistic reports of progress on a fusion power plant appear in the press from time to time, but some authorities now doubt that fusion power will ever be an economic reality. 

Renewable energy sources, (solar, wind etc.) must be harvested but these sources are neither large enough nor reliable enough to serve as base load source. Fission power is too dangerous. Of the current known energy sources, only fusion can supply safe energy for... 

It is highly unlikely that a nuclear fission power plant would ever explode like a nuclear bomb, but a loss of coolant accident could result in a melt down condition. 

No form of energy production is without risk. Make a list of the risks to society involved in fueling and operating a conventional coal-fired electric power plant, and compare them with the risks of fueling and operating a nuclear fission-powered electric plant. 

The parameter fp is the total number of fissions after irradiation time T per initial fissile atom, calculated by techniques described in Chap. 3. Equation (2.94) applies for operating times < 1.2614 X 10 s (4 years), shutdown times <10 s, and <3.0. A more detailed technique for calculating fission-product decay-heat power from an arbitrary time-dependent fission power, including contributions from the fission of U, U, and Pu, is given in the ANS Standard [A2]. 

Waste Products and Recycling Pu and Np are two of the most critical long-term components of nuclear waste from fission power reactors. The former is... 

The collective dose concept allows for extrapolation of the consequences from large scale introduction of nuclear power, which, in turn, establishes the need to ensure that the total annual dose stays within agreed safe limits. If it is assumed that fission power will be used for only about 1(X) y, the dose commitment integral may be limited to 100 y (sometimes called "incomplete collective dose"). 

Currently RTG s are used to produce power for many probes that are transmitting data from across the solar system [Furlong, 1999]. However, RTG s and other systems are limited in power generation because of the limited amount of available Pu, the expense of that isotope, and the fuel needed for a multi-kWe system. The weight per kWe may be unacceptable for some missions. Nuclear fission power systems have the potential to provide more power than RTG s. A drawback of reactor systems is that they are only mass and cost effective for missions requiring more than 10 kWe. Mars and other planets provide another set of potential challenges. The interaction between the outer surfaces of a heated reactor and the atmospheres of these planets is far more complicated than the interaction between the outer surfaces and deep space. 

FRANK VON HIPPEL, "Evolutionary Approach to Fission Power", (International Conference on Evaluation of Emerging Nuclear Fuel Cycle Systems Global-95, September 11-14, Versailles, France),. Vol.l, pp. 380-387... 

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