On the theory of power reactor noise—I

Abstract

An operating reactor has intrinsically fluctuating components in its state variables such as the thermal power, the outlet coolant temperature, the occupied region of control rods, etc. The fluctuations are generically called the reactor noise, the analysis of which, from both the theoretical and the experimental approach, is one of the problems of major concern in the field of nuclear science and engineering. The ultimate goal of the analysis lies in presenting the systematized methodology of diagnosis upon abnormality and malfunction of reactor components. The theoretical analysis of reactor noise has the most characteristic feature of integrity just as the nuclear industry has in industry. Its physical-mathematical analysis can be naturally regarded as a branch of statistical physics when one recalls the circumstances which the state of the art of the present statistical physics occupies in science. The integral nature of the reactor noise can be only clarified upon the standpoint that the theory of our reactor noise stands as a field of non-equilibrium classical statistical physics. The major effort of the present paper will be devoted to make as clear as possible the underlying physical-mathematical concepts which have been and will be used in the due course of development of the operating reactor noise theory. It is tried to make the above presentation as tasteful as possible by supplementing it with practical physical facts. Technical terms which are commonly used in modern statistical physics are explained so as to be accessible to reactor physicists and engineers.