NONDESTRUCTIVE TESTING IN THE CONTROL OF NUCLEAR MATERIALS

INTRODUCTION In the past few years there has been an. increasing interest in nondestructive testing methods for the measurement of the fuel content of nuclear materials. There are several logical reasons for this trend. During fabrication of fuel elements rigid controls must be kept on the overall fuel inventory, including the amounts placed in each element. The control and operation of nuclear reactors are directly dependent on the amount of fissionable material in the core. There must be enough for criticality but not too much, lest the efficiency suffers. In addition, excessive localized fuel concentration in a fuel element can cause a hot spot with subsequent fuel element failure. All of these factors have contributed to the \"need-to-know\" relative to fuel loading. Destructive analyses of selected elements can provide a degree of assurance that the remaining units are comparable, but this is very expensive and leaves much to be desired. By using nondestructive methods, every element can be evaluated and used if acceptable. Obviously, this provides better inventory control of fissionable material, no loss of acceptable elements during test, and more knowledge of the fuel in the reactor.