Слике страница
PDF
ePub

under government control. It has been proved possible for an independent inspectorate to review the accounting procedures used by the management, check the weighing and assaying equipment, make independent observations, etc., without seriously hampering the management. Experience of this kind has beer. particularly in the field of precious minerals where very small diversions are important; inspection to detect large-scale diversions should be even less of an interference.

5. The inspectorate must have unrestricted access to all equipment and all phases of the operations and have facilities for independent weighing, assay, and analysis.

It is clear that its complete independence of the local management must be unquestionable.

6. The number of guards and inspectors required for uranium mines and mills would not be great as compared with the operating staff.

The duties of the inspectors would require varying degrees of technical skill and could not be regarded as purely police functions. Persons could be regarded as qualified to serve as the head of a mine or mill inspectorate if, in addition to professional training and experience as engineers, they were given a short course of special instruction.

7. The comparison of weights and assays of the shipped material at the exit from the mill and on arrival at destination would provide a necessary check on possible diversion in transit.

Such checks are normally carried out in mining and refining and would be all the more important in the case of uranium concentrates.

Summary

Adequate safeguards against diversion from declared mines and mills are possible by a system of inspection, including guards, similar to normal managerial operating controls, provided that the inspectorate has unrestricted access to all equipment and operations and has facilities for independent weighing, assay, and analysis.

Findings for Mining and Milling of Thorium

1. The danger inherent in the diversion of thorium is less immediate than in the case of uranium.

Thorium cannot be used by itself for the production of atomic energy; it requires reactors which also use natural uranium or nuclear fuel.

2. The control of thorium would be in some respects more difficult than in the case of uranium.

The most common occurrence of thorium is in monazite sands; and the great extent of some deposits, which may be scattered over hundreds of miles, together with the relatively simple equipment required, makes illicit removals relatively easy. In view of the generally low content of thorium in the sands, however, only a large quantity of material would be significant, and frequent or large-scale illicit operations would probably be readily discovered.

3. Controls for thorium could still be of the same type as those for uranium.

The problems involved in the control of diversion from declared thorium deposits are fundamentally the same as those met in the control of uranium. A system of inspection applied to operations for extracting monazite from sands could follow the same general pattern of material accounting by technical methods together with guards to check shipments and prevent unauthorized removal.

The guarding and patrolling at monazite sand deposits would be relatively more important than in the case of most uranium

Occurrences.

Summary

Effective control of the raw material and concentrates of thorium is possible through a system of inspection similar to that found adequate for uranium.

Chapter 3: Safeguards Necessary To Detect and Prevent the Diversion of Uranium and Thorium From Declared Refineries and Chemical and Metallurgical Plants

Introduction

In connection with the problem of safeguards at refineries and chemical and metallurgical plants, the report of the Scientific and Technical Committee states:

"Only the application of very close and careful safeguards would provide an adequate assurance against the diversion from those plants of purified chemical compounds of natural uranium or thorium for the surreptitious production of explosive material for atomic weapons."

Findings

1. Total diversion to be dangerous would still be measured in terms of tons, but, because of the greater purity of the materials involved, the quantities concerned would be smaller than in the mining and milling stages.

2. An adequate system of inspection of uranium refineries and chemical and metallurgical plants could follow the normal patterns ordinarily used in the control of similar industrial operations.

As in the case of mines, a system of guards should be provided to control egress from the plant and to check the content and destination of shipments.

Methods of assay and measurement as a basis of accounting have been so developed that at some refineries and chemical and metallurgical plants the uncertainty (technically, the "probable error") on the balance sheet assessed over a period of about a year can be kept by good management to about one percent of the material entering the plant. It is possible in such plants to make a material balance with this accuracy at any time by a clean-up of the material undergoing processing. This naturally interrupts operations, but could reasonably be required at regular intervals and in addition whenever the suspicion of diversion arises. Without a clean-up the uncertainty in the balance over periods of about a month may be several times as great and may vary widely.

Facilities for independent assay and analysis would be part of any inspection system. These might take the form of a central laboratory serving a large number of different plants.

3. An adequate system of inspection could be so organized as not to interfere seriously with normal refining and chemical and metallurgical operations.

As in the case of mines, this kind of inspection is not a new problem but one that has been met and solved in commercial practice.

It is a matter of common practice for the management to shut the plant down at intervals and clean the material out of the various stages of the process. This enables a more accurate accounting to be made of the flow of material through the plant.

An additional safeguard, applicable only to refineries treating the ore concentrates, is a cross-check by comparison of the uranium balance with the balance of radium.

4. The inspectorate must have unrestricted access to all equipment and all phases of the operations and have facilities for independent weighing, assay, and analysis. It must also have the right to require the plant to be shut down for purposes of clean-up and accounting at appropriate times, and also to require efficient operating procedure, assuming to this extent a supervisory character.

5. The number of guards and inspectors required would not be great as compared with the operating staff.

The duties of the inspectors would require varying degrees of technical skill and could not be regarded as purely police functions.

A person could be regarded as qualified to serve as the head of the inspectorate of a refinery, chemical or metallurgical plant if, in addition to having a suitable professional degree and experience, he were given a few months of special instruction.

6. The comparison of weights and analysis of the shipped material when leaving refineries or chemical and metallurgical plants and on arrival at destination would provide a necessary check on possible diversion in transit.

Such checks are normally carried out in dealing with chemicals and would be all the more important in the case of pure uranium metal or compounds.

Summary

Adequate safeguards against diversion from declared refineries and chemical and metallurgical plants are possible by a system of inspection, including guards, similar to normal managerial operating controls, provided that the inspectorate has unrestricted access to all equipment and operations and has facilities for independent weighing, assay, and analysis and provided that it has the right to require the plant to be shut down for purposes of clean-up and accounting at appropriate times and to require efficient operating procedure.

At these stages, there is no fundamental difference between the processes for thorium and for uranium.

Chapter 4: Safeguards Necessary To Detect and Prevent the Diversion of Uranium From Declared Isotope Separation Plants

Introduction

The separation of U-235 from natural uranium and the enrichment of the U-235 content of natural uranium may play an important part in the peaceful use of atomic energy.

Although it is possible that many different processes may be devised for the separation of the isotope U-235 from naturally occurring uranium, existing plants fall into two main groups:

(a) Electromagnetic separation plants

(b) Plants based on diffusion processes

Isotope separation plants may increase the concentration of U-235 in uranium in varying degrees including that necessary for direct use in an atomic weapon. The necessity for adequate safeguards against diversion presents itself therefore, in these plants, in an acute form.

In this connection, the report of the Scientific and Technical Committee states:

"Production of nuclear fuels is the crucial stage in the operaSeparation plants for the production of uranium deliver nuclear fuel which, under

tions.

enriched in U-235 proper conditions, may be used directly for the manufacture of

[ocr errors]
[ocr errors]

atomic weapons. If, therefore, the strictest safeguards are not taken to prevent the material in the installations producing nuclear fuel from being diverted, the danger is extremely serious."

« ПретходнаНастави »