In developing a nuclear safeguards system, it is useful to think from a conceptual framework provided by three basic questions: What may be controlled? Who may do the controlling? And what are the means of control? We will discuss the first two questions here. Specific measures to prevent nuclear diversion, to detect completed nuclear thefts, to recover stolen nuclear materials, and to respond to nuclear threats will be explored in Chapter 8.

What May Be Controlled?

Nuclear material flows through and between a variety of facilities, from mines to radioactive waste storage. Special information is necessary in order to build and operate the facilities and produce, process, and use the materials flowing through the nuclear fuel cycles. And of course, nuclear industry would not happen without people. Thus, material, facilities, information, and people may be the subjects of control under a nuclear safeguards system.

Materials. Nuclear safeguards systems are based primarily on controls over materials which flow through the various nuclear fuel cycles. Therefore, detailed discussion of this aspect of safeguards is necessary at this point.

All nuclear material may be subject to safeguards. Control measures may be initially applied to every shovelful of ore containing uranium or thorium that is removed from the ground, or they may even apply to deposits of uranium and thorium ore in the earth's crust. Safeguards may extend to nuclear material as it flows throughout the fuel cycle and continue to apply to material that is recycled after chemical reprocessing. Measures to ensure against theft may apply to the fissionable material that is produced in a nuclear reactor and to each successive generation of fissionable material as it is produced. Safeguards may even extend to radioactive waste material that is stored permanently. Such a comprehensive control scheme is now unrealistic and unworkable. However, the original proposals for nuclear disarmament proposed by the U.S. government at the end of World War II—the so-called Baruch plan—called for just such a comprehensive scheme. At that time, the government believed such a scheme to be necessary as a precondition for the destruction of its own stockpile of nuclear bombs, which was then very small, and as a worldwide regulatory framework for the development of industrial uses of nuclear energy.

Alternatively, a variety of exemptions from a particular safeguards system are possible. Nuclear material may be exempt when it is present only in small quantities or in certain forms. Thus, if the total quantity of plutonium or high-enriched uranium in a country is less than one kilogram, that quantity is exempt from international safeguards under the NPT. Nuclear material may also