DOCSLIB.ORG

Nuclear Power

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Nuclear Power MORE CHAPTER 11, #6 Nuclear Power Nuclear Fission Reactors The discovery that several neutrons are emitted in the fission process led to specula- tion concerning the possibility of using these neutrons to initiate other fissions, thereby producing a chain reaction. On December 2, 1942, less than four years after Hahn and Strassmann’s discovery of fission, a group led by Enrico Fermi produced the first self-sustaining chain reaction in a nuclear reactor that they had constructed at the University of Chicago.24 To sustain a chain reaction in a fission reactor, one of the neutrons (on the average) emitted in the fission of 235U must be captured by another 235U nucleus and cause it to fission. The reproduction factor k of a reactor is defined as the average number of neutrons from each fission that cause a subsequent fission. In the case of 235U the maximum possible value of k is about 2.4, but it is normally less than this for two important reasons: (1) some of the neutrons may escape from the region contain- ing fissionable nuclei, and (2) some of the neutrons may be captured by nonfissioning nuclei in the reactor. If k is exactly 1, the reaction will be self-sustaining. If it is less than 1, the reaction will die out. If k is significantly greater than 1, the reaction rate will increase rapidly and “run away.” In the design of nuclear bombs, such a runaway reaction is necessary. In power reactors, the value of k must be kept very nearly equal to 1 (see Figure 11-50). If k is exactly equal to 1, the reactor is said to be critical; for k Ͻ 1, it is described as being subcritical and for k Ͼ 1 as supercritical. Since the neutrons emitted in fission mostly have energies of the order of 1 MeV or higher (see Figure 11-51), whereas the cross section for neutron capture leading to fission in 235U is largest at small energies as illustrated in Figure 11-52, the chain reaction can be sustained only if the neutrons are slowed down before they escape from the reactor. At high energies (1 to 2 MeV), neutrons lose energy rapidly by inelastic scattering from 238U, the principal constituent of natural uranium. (Natural uranium contains 99.28 percent 238U and only 0.72 percent fissile 235U.) Once the neu- tron energy is below the excitation energies of the nuclei in the reactor (about 1 MeV), the main process of energy loss is by elastic scattering, in which a neutron collides with a nucleus at rest and, by conservation of momentum, transfers some of its kinetic energy to the nucleus. Such energy transfers are efficient only if the masses of the two bodies are comparable. A neutron will not transfer much energy in an elastic collision with a heavy 238U nucleus. Such a collision is analogous to one between a marble and a billiard ball. The marble will be deflected by the much more massive billiard ball with essentially no change in its kinetic energy. Therefore, a moderator consisting of 75 76 More Chapter 11 FIGURE 11-50 Schematic representation of a fission chain reaction in 235U. The fission fragments are shown only for the first three fissions. The average number of neutrons produced is 2.4 per fission. In this example k ϭ 1.6. Notice that, while there are 42 neutrons in the diagram, the judicious placement of absorbers to absorb as few as two of those causing fission would be sufficient to make k ϭ 1 and control the reaction. 235U nucleus Fission fragments Neutron FIGURE 11-51 The energy spectrum of 1000 the neutrons emitted in the thermal- 235 neutron-induced fission of U. [Data Cloud chamber from R. B. Leachman, Proceedings of the Time of flight International Conference on the Peaceful 100 Emulsions Uses of Atomic Energy, vol. 2, United Nations, New York, 1956.] 10 Neutron abundance (relative) Neutron abundance 1 08110112 3 456 7 912 Neutron energy, MeV material such as water or graphite that contains light nuclei is placed around the fissile material in the core of the reactor to slow down the neutrons with relatively few colli- sions so as to minimize the number lost from the reactor. The neutrons are slowed down by elastic collisions with the nuclei of the moderator until they are in thermal equilibrium with the moderator, at which time they have approximately a Maxwell- Boltzmann energy distribution with average energy of 13>22kT. Table 11-5 lists the approximate number of collisions needed to reduce 1 MeV neutrons to thermal energy for a few nuclei. Reactors using ordinary water as a moderator cannot easily achieve k ϭ 1 using natural uranium as a fuel for a combination of reasons. First, although the average number of neutrons emitted per fission is 2.4 (equal to the maximum value of k), we have noted that some of these are lost by escaping from the reactor or being absorbed in nonfission reactions. Recalling from Section 11-7 that the total cross section is the More Chapter 11 77 4 10 FIGURE 11-52 Neutron-induced fission cross 235 238 103 sections for U and U. The region below 0.01 eV for 235U shows the 1>v dependence, as 2 584 b 10 does the cross section for the (n, ␥) reaction and 101 for the same reason. The radiative absorption 235U reaction competes with fission and has a cross 10 0 section of 97 b at 0.025 eV. The numerous –1 resonances between 1 eV and 100 eV are 10 236 238U associated with excited states of the U* Fission cross section, b 10 –2 nucleus. 0.025 eV 10 –3 10–3 10–2 10–1 10 0 101 10 2 103 10 4 10 5 106 10 7 Neutron energy, eV Table 11-5 Properties of selected nuclei as moderators Number of collisions Nucleus ␴(n, ␥) barns to thermalize 1H 0.333 18 2H 0.51 ϫ 10Ϫ3 25 4He 0 43 12C 3.5 ϫ 10Ϫ3 110 238U 2.75 2200 sum of the partial cross sections and recognizing that the ratio of the cross section for a particular reaction (Equation 11-62) and the total cross section is the relative proba- bility of that reaction occurring, we see that then the relative probability that a thermal ␴ >1␴ + ␴ 2 ␴ neutron will cause a fission reaction is given by f f a , where f is the partial ␴ cross section for fission and a is the partial cross section for all other kinds of absorp- tion of thermal neutrons. The latter are mainly (n, ␥) reactions. Thus, we can write k as ␴ = f k 2.4 ␴ + ␴ 11-68 f a ␴ ␴ The values of f and a for natural uranium are computed from the isotopic abun- dances above and the cross sections for each isotope. The fission cross section for 235U is 584 b for thermal neutrons, while that for 238U is zero. The cross sections for the (n, ␥) reactions are 97 b for 235U and 2.75 b for 238U (see Table 11-5 and Figure 11-52). ␴ ␴ The values of f and a are then given by 0.72 98.28 ␴ = ␴ 1235 2 + ␴ 1238 2 = + = U U 4.20 0 4.20 b f 100 f 100 f and 0.72 98.28 ␴ = ␴ 1235 2 + ␴ 1238 2 = + = U U 0.70 2.73 3.43 b a 100 a 100 a 78 More Chapter 11 FIGURE 11-53 Schematic diagram of the nuclear fuel cycle for uranium-fueled light-water reactors. The UF6 Fuel fabrication conversion plant converts Nuclear power plant solid U3O8, called yellowcake because of its color, into Plutonium Storage gaseous UF6 for the 235 enrichment facility. UF6 is Gaseous-diffusion Uranium 238 separated from UF6 based enrichment plant on the fact that both Reprocessing molecules have the same UF6 conversion and conversion average kinetic energy, > (3 2)kT, and hence different Mining diffusion rates due to their and High-level milling Low-level slightly different masses. The waste waste complete cycle includes the repository reprocessing facility and the repository for highly Trench burial radioactive fission products. Therefore, the largest possible value of k that we Table 11-6 Thermal-neutron fission cross can expect from natural uranium used as a reactor sections for selected nuclei fuel is, from Equation 11-68, Cross section Critical energy ␴ = f = 4.20 = Nuclide (barns) for A ϩ 1 (MeV) k 2.4 ␴ + ␴ 2.4 + 1.32 f a 4.20 3.43 229Th 30 8.3 This value is already quite close to 1.0, so if loss of neutrons by leakage from the reactor or by 230Th Ͻ10Ϫ3 8.3 absorption in the moderator is significant, the 230Pa 1500 7.6 value of k may be easily less than 1.0. Because of Ϫ the relatively large neutron capture cross section 233Pa Ͻ10 1 7.1 for the hydrogen nucleus (see Table 11-5), reactors 233U 531 6.5 using ordinary water as a moderator and natural Ϫ uranium as a fuel have difficulty reaching k ϭ 1. 234U Ͻ5 ϫ 10 3 6.5 By enriching the uranium fuel in 235U, that is, by 235U 584 6.2 increasing the 235U content from 0.7 percent to, Ϫ for example, 3 percent, the value of k computed 238U 2.7 ϫ 10 6 5.9 from Equation 11-68 becomes 1.82, sufficient to 236Np 3000 5.9 make k ϭ 1 attainable in operation. (Figure 11-53 238Np 17 6.0 shows where the enrichment process fits into the uranium fuel cycle.) Natural uranium can be used 239 Pu 742 6.0 if heavy water (D2O) is used instead of ordinary 240Pu Ͻ8 ϫ10Ϫ2 6.3 (light) water (H2O) as the moderator.
Load more

Recommended publications
  • 1 Phys:1200 Lecture 36 — Atomic and Nuclear Physics
    1 PHYS:1200 LECTURE 36 — ATOMIC AND NUCLEAR PHYSICS (4) This last lecture of the course will focus on nuclear energy. There is an enormous reservoir of energy in the nucleus and it can be released either in a controlled manner in a nuclear reactor, or in an uncontrolled manner in a nuclear bomb. The energy released in a nuclear reactor can be used to produce electricity. The two processes in which nuclear energy is released – nuclear fission and nuclear fusion, will be discussed in this lecture. The biological effects of nuclear radiation will also be discussed. 36‐1. Biological Effects of Nuclear Radiation.—Radioactive nuclei emit alpha, beta, and gamma radiation. These radiations are harmful to humans because they are ionizing radiation that have the ability to remove electrons from atoms and molecules in human cells. This can lead to the death or alterations of cells. Alteration of the cell can transform a healthy cell into a cancer cell. The hazards of radiation can be minimized by limiting ones overall exposure to radiation. However, there is still some uncertainty in the medical community about the possibility the effect of a single radioactive particle on the bottom. In other words, are the effects cumulative, or can a single exposure lead to cancer in the body. Exposure to radiation can produce either short term effects appearing within minutes of exposure, or long term effects that may appear in years or decades or even in future generations due to changes in DNA. The effects of absorbing ionizing radiation is measured in a unit called the rem.
    [Show full text]
  • Enrico Fermi
    Fermi, Enrico Inventors and Inventions Enrico Fermi Italian American physicist Fermi helped develop Fermi-Dirac statistics, which liceo (secondary school) and, on the advice of Amidei, elucidate the group behavior of elementary particles. joined the Scuola Normale Superiore at Pisa. This elite He also developed the theory of beta decay and college, attached to the University of Pisa, admitted only discovered neutron-induced artificial radioactivity. forty of Italy’s top students, who were given free board Finally, he succeeded in producing the first sustained and lodging. Fermi performed exceedingly well in the nuclear chain reaction, which led to the discovery highly competitive entrance exam. He completed his of nuclear energy and the development of the university education after only four years of research and atomic bomb. studies, receiving his Ph.D. in physics from the Univer- sity of Pisa and his undergraduate diploma from the Born: September 29, 1901; Rome, Italy Scuola Normale Superiore in July, 1922. He became Died: November 28, 1954; Chicago, Illinois an expert theoretical physicist and a talented exper- Primary field: Physics imentalist. This rare combination provided a solid foun- Primary inventions: Controlled nuclear chain dation for all his subsequent inventions. reaction; Fermi-Dirac statistics; theory of beta decay Life’s Work After postdoctoral work at the University of Göttingen, Early Life in Germany (1922-1923), and the University of Leiden, Enrico Fermi (ehn-REE-koh FUR-mee) was the third in the Netherlands (fall, 1924), Fermi took an interim po- child of Alberto Fermi and Ida de Gattis. Enrico was very sition at the University of Florence in December, 1924.
    [Show full text]
  • Nuclear Weapons Technology 101 for Policy Wonks Bruce T
    NUCLEAR WEAPONS TECHNOLOGY FOR POLICY WONKS NUCLEAR WEAPONS TECHNOLOGY 101 FOR POLICY WONKS BRUCE T. GOODWIN BRUCE T. GOODWIN BRUCE T. Center for Global Security Research Lawrence Livermore National Laboratory August 2021 NUCLEAR WEAPONS TECHNOLOGY 101 FOR POLICY WONKS BRUCE T. GOODWIN Center for Global Security Research Lawrence Livermore National Laboratory August 2021 NUCLEAR WEAPONS TECHNOLOGY 101 FOR POLICY WONKS | 1 This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory in part under Contract W-7405-Eng-48 and in part under Contract DE-AC52-07NA27344. The views and opinions of the author expressed herein do not necessarily state or reflect those of the United States government or Lawrence Livermore National Security, LLC. ISBN-978-1-952565-11-3 LCCN-2021907474 LLNL-MI-823628 TID-61681 2 | BRUCE T. GOODWIN Table of Contents About the Author. 2 Introduction . .3 The Revolution in Physics That Led to the Bomb . 4 The Nuclear Arms Race Begins. 6 Fission and Fusion are "Natural" Processes . 7 The Basics of the Operation of Nuclear Explosives. 8 The Atom . .9 Isotopes . .9 Half-life . 10 Fission . 10 Chain Reaction . 11 Critical Mass . 11 Fusion . 14 Types of Nuclear Weapons . 16 Finally, How Nuclear Weapons Work . 19 Fission Explosives . 19 Fusion Explosives . 22 Staged Thermonuclear Explosives: the H-bomb . 23 The Modern, Miniature Hydrogen Bomb . 25 Intrinsically Safe Nuclear Weapons . 32 Underground Testing . 35 The End of Nuclear Testing and the Advent of Science-Based Stockpile Stewardship . 39 Stockpile Stewardship Today . 41 Appendix 1: The Nuclear Weapons Complex .
    [Show full text]
  • 22.05 Reactor Physics – Part One Course Introduction
    22.05 Reactor Physics – Part One Course Introduction 1. Instructor: John A. Bernard 2. Organization: Homework (20%) Four Exams (20% each; lowest grade is dropped) Final Exam (3.0 hours) (20%) 3. Text: The text book for this course is: Introduction to Nuclear Engineering, 3rd Edition, by John Lamarsh. This covers basic reactor physics as part of a complete survey of nuclear engineering. Readings may also be assigned from certain of the books listed below: Nuclear Reactor Analysis by A. F. Henry Introduction to Nuclear Power by G. Hewitt and J. Collier Fundamentals of Nuclear Science and Engineering by J. Shultis and R. Faw Atoms, Radiation, and Radiation Protection by J. Turner Nuclear Criticality Safety by R. Kneif Radiation Detection and Measurement by G. Knoll 4. Course Objective: To quote the late Professor Allan Henry: “The central problem of reactor physics can be stated quite simply. It is to compute, for any time t, the characteristics of the free-neutron population throughout an extended region of space containing an arbitrary, but known, mixture of materials. Specifically we wish to know the number of neutrons in any infinitesimal volume dV that have kinetic energies between E and E + ∆E and are traveling in directions within an infinitesimal angle of a fixed direction specified by the unit vector Ω. If this number is known, we can use the basic data obtained experimentally and theoretically from low-energy neutron physics to predict the rates at which all possible nuclear reactions, including fission, will take place throughout the region. Thus we can 1 predict how much nuclear power will be generated at any given time at any location in the region.” There are several reasons for needing this information: Physical understanding of reactor safety so that both design and operation is done intelligently.
    [Show full text]
  • Memorandum to Participants JASON 1994 Summer Study
    Hydronnclear Testing and the Comprehensive Test Ban: Memorandum to Participants JASON 1994 Summer Study Natural Resources Defense Council, Inc. 1350 New York Avenue, NW, Suite 300 Washington, D.C. 20005 Tel (main): (202) 783-7800 Cochran (direct dial): (202) 624-9329 Paine (direct dial): (202) 624-9350 Fax: (202) 783-5917 INTERNET: [email protected] Although no commonly accepted defInition exists, a "hydronuclear test" may be generally described as a nuclear weapons test, or high-explosive driven criticality experiment, characterized by a nuclear energy release that is insuffIcient to heat the core material to the plasma temperatures that would cause it to explode "like a bomb." In such a test, the TNT equivalent energy release from fission would therefore not exceed the amount released by the chemical high explosive used to compress the fIssile material, and could be considerably ,less. Nuclear-weapon states, and possibly other states, also perform high-explosive driven implosion experiments using fusjon material, although" these' are not nonnally characterized as "hydronuclear tests". Hydronuclear tests can serve a useful role in the development of the full spectrum of unboosted fIssion weapons, including'first generation nuclear weapons of the implosion type with yields in the 5 to 30 kiloton range, more sophisticated designs with yields up to about a megaton, and advanced micro-nuclear weapons with yields of 5 to 500 tons. For pure fIssion weapons hydronuclear tests can be used to:' * optimize the timing of initiation of the
    [Show full text]
  • Cm Element of the Day Curium (Kewreeәm) Is a Transuranic Radioactive Chemical Element with the Symbol Cm and Atomic Number 96
    Cm Element of the Day Curium (kewreeәm) is a transuranic radioactive chemical element with the symbol Cm and atomic number 96. This element of the actinide series was named after Marie Curie and her husband Pierre Curie both were known for their research on radioactivity. Most curium is produced by bombarding uranium or plutonium with neutrons in nuclear reactors – one ton of spent nuclear fuel contains about 20 grams of curium. Curium is a hard, dense, silvery metal with a relatively high melting point and boiling point for an actinide. Curium readily oxidizes, and its oxides are a dominant form of this element. When introduced into the human body, curium accumulates in the bones, lungs and liver, where it promotes cancer. All known isotopes of curium are radioactive and have a small critical mass for a sustained nuclear chain reaction. Curium is used in production of heavier actinides and of the 238­Pu radionuclide for power sources in artificial pacemakers. It served as the α source in the alpha particle X­ray spectrometers used to analyze rock composition. Curium's outer electrons have a principal quantum level of four. How many electrons may fit into this orbital? 1 Chemistry 1. Warm­Up ­5 2. Review Book Homework ­10 3. Notes­ 20 4. Complete POGIL Activity ­30 5. Test Review ­20 Announcements Due Today: Mole Airlines Extra Credit Due Today: Read pages 317 to 331 and answer questions 1 ­ 9 odd, 15, 17, 19 and 25. Begin work on Study Guide! ­ Will be available after school today. Semester Review Session Thursday at 3:00 pm 2 Homework Review 3 POGIL Activity with Modeling Kits! ­ Turn in 4 Review/Notes 5 Quantum Numbers ­ Review Questions 1.
    [Show full text]
  • Highly Enriched Uranium: Striking a Balance
    OFFICIAL USE ONLY - DRAFT GLOSSARY OF TERMS APPENDIX F GLOSSARY OF TERMS Accountability: That part of the safeguards and security program that encompasses the measurement and inventory verification systems, records, and reports to account for nuclear materials. Assay: Measurement that establishes the total quantity of the isotope of an element and the total quantity of that element. Atom: The basic component of all matter. Atoms are the smallest part of an element that have all of the chemical properties of that element. Atoms consist of a nucleus of protons and neutrons surrounded by electrons. Atomic energy: All forms of energy released in the course of nuclear fission or nuclear transformation. Atomic weapon: Any device utilizing atomic energy, exclusive of the means for transportation or propelling the device (where such means is a separable and divisible part of the device), the principal purpose of which is for use as, or for development of, a weapon, a weapon prototype, or a weapon test device. Blending: The intentional mixing of two different assays of the same material in order to achieve a desired third assay. Book inventory: The quantity of nuclear material present at a given time as reflected by accounting records. Burnup: A measure of consumption of fissionable material in reactor fuel. Burnup can be expressed as (a) the percentage of fissionable atoms that have undergone fission or capture, or (b) the amount of energy produced per unit weight of fuel in the reactor. Chain reaction: A self-sustaining series of nuclear fission reactions. Neutrons produced by fission cause more fission. Chain reactions are essential to the functioning of nuclear reactors and weapons.
    [Show full text]
  • Hydronuclear Testing Or a Comprehensive Test Ban?
    Hydronuclear Testing or a Comprehensive Test Ban? Natural Resources Defense Council, Inc. 1350 New York Avenue, NW, Suite 300 Washington, D.C. 20005 Tele: (202) 783-7800 Fax: (202) 783-5917 Hydronuclear tests--tests of nuclear weapons at yields less than about two kilograms of TNT equivalent--are useful for the assessment of new designs and the safety of existing designs. Hydronuclear tests can serve a useful role in the development of the full spectrum of unboosted fission weapons, including first generation nuclear weapons of the implosion type with yields in the 10 to 30 kiloton range, more sophisticated designs with yields up to about a megaton, and advanced micro-nuclear weapons with yields of 5 to 500 tons. Since hydronuclear tests do not generate sufficient yield to create the conditions for fusion of deuterium and tritium in the core, such tests do not provide a reliable means if extrapolating the performance of new "boosted" fission weapons and thermonuclear primaries, or advanced thermonuclear secondaries. In negotiating the Comprehensive Test Ban Treaty (CTBT) the current strategy of the U.S. Government is not to define in the treaty what constitutes a nuclear test. If this strategy is successful and the treaty is ratified, the U.S. Government will interpret the CTBT to permit hydronuclear testing if such a test is conducted by any other country. A program of hydronuclear testing by any of the weapon states will encourage the others to conduct similar tests, with the results of undermining the purpose of the treaty. If hydronuclear tests are permitted under a CTB, the nuclear test sites of declared nuclear powers may be maintained, in part, to facilitate the conduct of hydronuclear tests.
    [Show full text]
  • 10.1 Nuclear Energy Nuclear Fission Nuclear Fusion
    Final Exam • Wed Dec. 9 from11:30am-2:29pm York 2722 • Will cover all the course material including the last week • 25 questions –multiple choice. • You are allowed to bring 1sheet of paper with equations on both sides, scratch paper for calculation, calculator • You must bring a scantron form and a picture id. 10.1 Nuclear energy Nuclear Fission Nuclear Fusion Curve of the Binding Energy/nucleon Natural radioactivity fission Many elements found in nature are unstable and decay emitting radioactivity. fusion These include Uranium, 238U , Radon 224Ra and Potassium 40K. Carbon 14C, The half lives of natural radio-isotopes are long. Not useful as sources for power. Low Power output. Energy can be released by nuclear reactions of Fusion and Fission Nuclear Power Induced Nuclear reactions Can result in short half lives- fast reactions-high energy density • Nuclear power requires induced nuclear Combining nuclei (Fusion) fission. 22DD+ ⎯⎯→+ 31 TH+ Energy • Nuclear fission can be induced by 11 11 neutrons in a chain reaction. • Nuclear fusion can be induced by Neutron reactions (Fission) collisions at high temperature. 1 235 141 92 1 09256360nU+⎯⎯→++ BaKr3n+ Energy 1 Fission of Uranium Fission of Uranium Strassman and Hahn (1939) Fermi (1936) Irradiated Uranium with neutrons Bombard uranium with Fast Slow Detected Barium neutrons neutrons neutrons Conclude Uranium nuclei splits into smaller fragments Found induced radioactivity 1n+⎯⎯ 235 U→+ 141 Ba other _products Neutron parafilm uranium “Transuranium elements” 09256 Source (radon+Be) Liquid
    [Show full text]
  • Those Early Days As We Remember Them - Part VII | Met Lab and Early Argonne History | Argonne National Laboratory
    Those early days as we remember them - Part VII | Met Lab and Early Argonne History | Argonne National Laboratory Those early days as we remember them Part VlI Norman Hilberry, director of Argonne National Laboratory (seated) and Dean E. Dalquest (standing), superintendent of the laboratory's Graphic Arts division. They are examining an historic galvanometer recording of the fluctuation in a neutron density in Chicago Pile No. 1. The document, restored and framed in 1958, could be called a birth certificate of the atomic age. Image Credit: University of Chicago Photographic Archive, [apf1-02809], Special Collections Research Center, University of Chicago Library. By Norman Hilberry Argonne Director, 1956-1961 Associate, then Deputy Director, 1946-1956 My association with the nuclear energy business began with the kind of startling abruptness that was to become characteristic of the way in which so many of the Metallurgical Project staff joined — or, as some of them felt, were shanghied. Returning home late on the evening of Saturday, December 20, 1941, from a New York University Faculty Club Christmas party, I found a telegram waiting for me. It said, “Need you for important war job. Please arrange immediate leave of absence and report to my office at earliest possible time.” It was signed “Arthur C.” I rousted Martin D. Whitaker, my department chairman, out of bed early Sunday morning, read him the telegram, arranged the leave of absence, caught the Century at midmorning, and was in Compton’s office at The University of Chicago on Monday morning, December 22, 1941, almost as soon as he was.
    [Show full text]
  • Gate Frame Question
    UNIT TEN INTRODUCTION TO NUCLEAR REACTORS The licensees of nuclear facilities have primary responsibility for planning and implementing emergency measures within their site boundaries. These emergency measures include corrective actions at the site and protective measures and aid for persons onsite. Since facility licensees cannot do this alone, it is a necessary part of the facility’s emergency planning to make advance arrangements with State and local organizations for special emergency assistance such as ambulance, medical, hospital, fire and police services. State and local governments have responsibility for planning and implementing protective actions outside the site boundaries. Radiological response team members from State and local emergency services will be better prepared to carry out these responsibilities with some knowledge of nuclear power plant structure, operations and emergency response procedures. The teaching points included in this unit should be recognized as a review by those who have completed the FEMA radiological series prerequisites or who have experience in the nuclear power industry. You are notified of a site area emergency at a nuclear power GATE FRAME plant located nine miles from your town. The meteorologist QUESTION has confirmed that if a release occurs, the town will be directly in the path of the plume. Part of the town is in the plume exposure pathway and the rest is within the ingestion pathway. How do you interpret this information? ________________________________________________ ________________________________________________ ________________________________________________ 1-1 Unit Ten Introduction to Nuclear Reactors ANSWER A site area emergency means that events are in process or have occurred that involve actual major failures of plant functions needed for protection of the public.
    [Show full text]
  • An Atomic History Chapter 2
    An Atomic History 0-3 8/11/02 7:31 AM Page 18 Chapter Two 19 THE FERMI-SZILARD PILE AND URANIUM RESEARCH The first government funding for nuclear research was allocated to purchase graphite and uranium oxide for the chain reaction experiments being organized by Fermi and World War II and the Manhattan Project Szilard at Columbia University in February 1940.2 This work, which began in New York 2 City, soon spread to Princeton, the University of Chicago, and research institutions in California.3 Even at this stage, the scientists knew that a chain reaction would need three major components in the right combination: fuel, moderator, and coolant. The fuel would contain the fissile material needed to support the fission process. The neutrons generated by the fission process had to be slowed by the moderator so that they could initiate addi- tional fission reactions. The heat that resulted from this process had to be removed by the coolant. Fermi’s initial research explored the possibility of a chain reaction with natural urani- The 1930s were a time of rapid progress in the development of nuclear physics. um. It was quickly determined that high-purity graphite served as the best neutron moder- Research accelerated in the early years of the Second World War, when new developments ator out of the materials then available.4 After extensive tests throughout 1940 and early were conceived and implemented in the midst of increasing wartime urgency. American 1941, Fermi and Szilard set up the first blocks of graphite at Columbia University in government interest in these developments was limited at first, but increased as the war September 1941.
    [Show full text]