## 213 Effects of Distance and Shielding

For protection, advantage can be taken of the fact that radiation intensities decrease with distance from the source, varying as the inverse square of the distance. Let us illustrate by an idealized case of a small source, regarded as a mathematical point, emitting S particles per second, the source strength. As in Fig. 21.1, let the rate of flow through each unit of area of a sphere of radius R about the point be labeled f (cm-2 - s-1). The flow through the whole sphere surface of area 4pR2 is...

## 124 Waste Heat Rejection

The generation of electric power by consumption of any fuel is accompanied by the release of large amounts of waste heat. For any conversion process the thermal efficiency, e, the ratio of work done to thermal energy supplied, is limited by the temperatures at which the system operates. According to the second law of thermodynamics, an ideal cycle has the highest efficiency value, where 71 and T2 are the lowest and highest absolute temperatures (Kelvin, C+273 Rankine, F+460). For example, if...

## 163 Basis for Limits of Exposure

A typical bottle of aspirin will specify that no more than two tablets every four hours should be administered, implying that a larger or more frequent dose would be harmful. Such a limit is based on experience accumulated over the years with many patients. Although radiation has medical benefit only in certain treatment, the idea of the need for a limit is similar. As we seek to clean up the environment by controlling emissions of waste products from industrial plants, cities, and farms, it is...

## 32 The Decay

The rate at which a radioactive substance disintegrates (and thus the rate of release of particles) depends on the isotopic species, but there is a definite decay law that governs the process. In a given time period, say one second, each nucleus of a given isotopic species has the same chance of decay. If we were able to watch one nucleus, it might decay in the next instant, or a few days later, or even hundreds of years later. Such statistical behavior is described by a constant property of...

## 2212 References for Chapter

Cochran and Nicholas Tsoulfanidis, The Nuclear Fuel Cycle Analysis and Management, 2nd Ed., American Nuclear Society, La Grange Park, IL, 1999. The Nuclear Waste Primer, by The League of Women Voters Education Fund, Lyons & Burford, New York, 1993. Brief and elementary information. Raymond L. Murray, Radioactive Waste Storage and Disposal, Proceedings of the IEEE, Vol. 74, No. 4, April 1986, p. 552. A survey article that covers all aspects. Raymond L. Murray, Understanding...

## 1712 References for Chapter

Harvard University Department of Molecular and Cellular Biology. DOE Information Bridge http www.osti.gov bridge Search on A Vital Legacy for atoms in biology. 4807K pdf file. S. James Adelstein and Frederick J. Manning, Eds., Isotopes for Medicine and the Life Sciences, National Academy Press, Washington, 1995. Describes sources of stable and radioactive isotopes and recommends a national dedicated accelerator. Medical Isotopes Production http www.sandia.gov Search on molybdenum-99 DOE Isotope...

## 46 Neutron Migration

When fast neutrons, those of energy of the order of 2 MeV, are introduced into a medium, they make inelastic or elastic collisions with nuclei. Upon each elastic collision neutrons are deflected in direction, they lose energy, and they tend to migrate away from their origin. Each neutron has a unique history, and it is impractical to keep track of all of them. Instead, we seek to deduce average behavior. First, we note that the elastic scattering of a neutron with an initially stationary...

## 133 The Fast Breeder Reactor

Liquid metal fast breeder reactors (LMFBR) have been operated successfully throughout the world. In the United States the Experimental Breeder Reactor I at Idaho Falls was the first power reactor to generate electricity, in 1951. Its successor, EBR II, was used from 1963 to 1994 to test equipment and materials (see References). The Fermi I reactor built near Detroit was the first intended for commercial application. It was started in i963 but was damaged by blockage of coolant flow passages and...

## 2310 References for Chapter

Federal Government Agencies Directory A comprehensive set of links maintained by Louisiana State University Libraries. History of Energy 1800-1994 Chronology of events in U.S. and Canada. Environmental Protection Agency http www.epa.gov Select About EPA EPA's Budget or Policy Statements and Strategy Documents Strategic Plan George T. Mazuzan and J. Samuel Walker, Controlling the Atom The Beginnings of Nuclear Regulation 1946-1962, California University Press, Berkeley and Los Angeles,...

## 207 References for Chapter

Hewlett and Francis Duncan, Nuclear Navy 1946-1962, University of Chicago Press, Chicago, IL, 1974. Commander William R. Anderson, U.S.N., and Clay Blair, Jr., Nautilus-90-North, World Publishing Co., Cleveland, OH, 1959. An account by the chief officer of the nuclear submarine Nautilus of the trip to the North Pole. Herbert J. Gimpel, The United States Nuclear Navy, Franklin Watts, Inc., New York, 1965. History of the Polaris submarine, with many photographs. Nautilus Museum http...

## 1910 References for Chapter

Ronald Allen Knief, Nuclear Criticality Safety Theory and Practice, American Nuclear Society, La Grange Park, IL, 1985. Methods of protection against inadvertent criticality, with an appendix on the Three Mile Island recovery program. Brian L. Koponen, Ed., Nuclear Criticality Safety Experiments, Calculations, and Analyses-1958 to 1998 Compilation of Papers from the Transactions of the American Nuclear Society, Golden Valley Publications, Livermore, CA, 1999. Atomic Energy Commission, 1943-1970...

## 122Heat Generation and Removal

The transfer of heat by conduction in a flat plate (insulated on its edges) is reviewed. If the plate has a thickness x and cross-sectional area 4, and the temperature difference between its faces is DT, the rate of heat flow through the plate, Q, is given by the relation where k is the conductivity, with typical units J s- C-cm. For the plate, the slope of the temperature is the same everywhere. In a more general case, the slope may vary with position, and the rate of heat flow per unit area Q...

## 167 References for Chapter

Genentech's Access Excellence Classical Collection. Explains the role of radioactive labeling and displays the structure of DNA. Bruce Alberts, Dennis Bray, Alexander Johnson, Julian Lewis, Martin Raff, Keith Roberts, and Peter Walter, Essential Cell Biology An Introduction to the Molecular Biology of the Cell, Garland Publishing, New York, 1997. Highly recommended. Stunning diagrams and readable text. Jacob Shapiro, Radiation Protection, 3rd edition, Harvard University Press, Cambridge MA,...

## 134 Breeding and Uranium Resources

From the standpoint of efficient use of uranium to produce power, it is clearly preferable to employ a breeder reactor instead of a converter reactor. The breeder has the ability to use nearly all of the uranium rather than a few percent. Its impact can be viewed in two different ways. First, the demand for natural uranium would be reduced by a factor of about 30, cutting down on fuel costs while reducing the environmental effect of uranium mining. Second, the supply of fuel would last longer...

(c) 2.56 x 10-13 m, (d) 3.58 x 10-13 19.1. 0.0157, 2.40 7.7 x 10-4 s 63.8 s. 19.3. (a) and (b) 1.16 x 10-5 s. 19.6. 0.0068, 0.0046, 0.0034, 0.0021. 19.9. 117, 138, 150, 152, 153 yes. 19.14. B(3) (3 2)Bi, B(4) (8 5)Bi. 20.2. 7.81 km s 22,300 mi, 35,900 km. 21.1. 1558 mrems y, 371 mrems y. 21.7. (in ilCi ml) 3.14 x 10-7, 2.98 x 10-7, 3.34 x 10-7. 21.8. 7.60 days, 94.6 days, 69.6 days. 21.9. (in mrem) I 0.002, C 0.044, T 0.046, A 0.044. Teenager (liver). Yes. 22.1. 25,400 (49 ) 95,900 (85 ). 22.3....

## 98 References for Chapter

Smyth Report on Separation of Uranium Isotopes (1945) http www.fas.org nuke hew Smyth Reproduction of Chapters IX-XI by Federation of American Scientists Stelio Villani, Isotope Separation, American Nuclear Society, La Grange Park, IL, 1976. A monograph that describes most of the techniques for separating isotopes, including theory, equipment, and data. Uranium Enrichment http www.uic.com.au nip33.htm Facts and figures in a briefing paper by Uranium Information Centre (Australia) Calutrons at...

## Computer Exercises

A simplified version of the analysis of neutron population growth is called the one-delayed-group model. The six emitters listed in Ex. 19.12 are replaced by a single emitter with mean life t 12.7 s, effective neutron lifetime 1 0.083 s, decay constant 1 0.0785 s-1, total fraction b 0.0065. Differential equations for the neutron population n and the delayed emitter concentration c are written To solve, finite difference methods are used in the Lotus 1-2-3 program OGRE (One Group Reactor...

## 29Exercises

Find the number of carbon 162C atoms in 1 cm3 of graphite, density 1.65 g cm3. 2.2. Estimate the radius and volume of the gold atom, using the metal density of 19.3 g cm3 and atomic weight close to 197. Assume that atoms are located at corners of cubes and that the atomic radius is that of a sphere with volume equal to that of a cube. 2.3. Calculate the most probable speed of a neutron gas at temperature 20 C 293K , noting that the mass of a neutron is 1.67 x 10-27 kg. 2.4. Prove that the...

## 2110 References for Chapter

By Bruce Busby, Idaho State University. Bernard Schleien, Lester A. Slayback, Jr., and Brian Kent Birky, Editors, Handbook of Health Physics and Radiological Health, 3rd Ed., Williams amp Wilkins, Baltimore, 1998. A greatly expanded version of a classical document of 1970. Herman Cember and Herbert Cember, Introduction to Health Physics, 3rd Ed., McGraw-Hill, New York, 1996. A thorough and easily understood textbook. Herman Cember and Thomas E. Johnson, The Health...

## 48Exercises

The energy of formation of water from its constituent gases is quoted to be 54,500 cal mole. Verify that this corresponds to 2.4 eV per molecule of H2O. 4.2. Complete the following nuclear reaction equations 0n N 1H, 2H 9Be 0n. 4.3. Using the accurate atomic masses listed below, find the minimum amount of energy an a particle must have to cause the transmutation of nitrogen to oxygen. 174N 14.003074, 4 He 4.002603, O 16.999132, JH 1.007825. 4.4. Find the energy release in the reaction 63Li...