Plutonium-power reactors discussion

Np. The isotope Np is formed in considerable quantities in reactors, by the nuclide chains initiated by (n, y) reactions in and by ( , 2n) reactions in Neutron capture by Np leads through Np to Pu, which is the principal alpha-emitting constituent of plutonium in power reactors. To produce Pu for use as a heat source for thermoelectric devices, neptunium has been recovered from irradiated uranium to form target elements for further irradiation in reactors. Commercial processes designed for this recovery are discussed in Chap. 10. 

As discussed in 19.10, Pu has been formed in natural uranium reactors at a later stage of the earth s evolution. Many thousands of tons of plutonium has been synthesized in commercial and military reactors the annual global production rate in nuclear power reactors in the year 2000 was 1000 tons/y, contained in the spent fuel elements. The nuclear reactions and chemical separation processes are presented in Chapters 19 and 21. The build-up of heavier elements and isotopes by n-irradiation of Pu in nuclear reactors is illustrated in Figures 16.2 and 16.3. The accumulated amount of higher actinides within the European commimity is many tons for Np, Pu and Am, and himdreds of kg of Cm the amounts in the United States and Russia are of the same magnitude. 

Because the plutonium-burning reactor proposed in this report is assumed to use a metal or oxide fuel, (such as Pu-Al, Pu-Zr02, or Pu-ZrH).6) the potential for an energetic steam explosion is of some concern, provided an accident sequence can be identified that leads to large quantities of molten fuel and cladding. The purpose of this section is to discuss some of the steam explosion concerns involving aluminum-water and zirconium-water in relation to the proposed low power density, low flow plutonium-burning reactor. 

Basic components. Before discussing the Los Alamos Molten Plutonium Reactor (LAMPRE) proposal in detail, the following resume will treat some of the possibilities for the three basic components of a power reactor the fuel, the container, and the coolant. 

Uranium is used as the primai-y source of nuclear energy in a nuclear reactor, although one-third to one-half of the power will be produced from plutonium before the power plant is refueled. Plutonium is created during the uranium fission cycle, and after being created will also fission, contributing heat to make steam in the nuclear power plant. These two nuclear fuels are discussed separately in order to explore their similarities and differences. Mixed oxide fuel, a combination of uranium and recovered plutonium, also has limited application in nuclear fuel, and will be briefly discussed. 

Since plutonium is the actinide generating most concern at the moment this review will be concerned primarily with this element. However, in the event of the fast breeder reactors being introduced the behaviour of americium and curium will be emphasised. As neptunium is of no major concern in comparison to plutonium there has been little research conducted on its behaviour in the biosphere. This review will not discuss the behaviour of berkelium, californium, einsteinium, fermium, mendelevium, nobelium and lawrencium which are of no concern in the nuclear power programme although some of these actinides may be used in nuclear powered pacemakers. Occasionally other actinides, and some lanthanides, are referred to but merely to illustrate a particular fact of the actinides with greater clarity. 

A series of fast reactor critical experiments at the zero-power plutonium reactor (ZPPK) is providing benchmark physics data for both conventional and heterogeneous LMi BKs in tlie 600- to 700-MW(e) size class, this data base is similar to one established by an earlier series related to fast reactors of 3S0-MW(e) size. This paper discusses the scope of the program, outlines the measurements being emphasized, and presents some results from the conventional core experiments. 

The effects of the production of Pu and the higher isotopes of plutonium in a high-power thermal reactor will be discussed in detail in Chapter 4. For the present, we will note the importance of the conversion ratio, which is defined as... 

Because all reactors without fertile material at the same power level and capacity factor bum plutonium at the same rate, nearly any concept could accomplish this mission. There was no time to investigate several different concepts without fertile materials. Other concepts also have desirable features and may be better overall choices than the one that has been selected. Some of these concepts are listed below, along with ideas and features that have been discussed. This list is certainly not complete. 

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