Introductory Neutronics/Introduction

The subject of nuclear engineering is studied primarily by two groups of professionals; those concerned with medical applications of nuclear physics, and those concerned with reactor physics. The medical application of nuclear physics is broadly termed "Radiation Health Physics" and analyzes the effects of radiation on biological systems and the use of radiation for the study of biological systems. Reactor physics covers the interaction of radioactive and non-radioactive inorganic substances and is primarily focused on the inducing and sustaining of nuclear chain reactions, this field of study is generally known as neutronics and is the subject of this text; reactor physics also covers the transfer of heat and fluid in reactor systems, which is critical for maintaining both safety and the physical viability of a nuclear chain reaction, this field of study is generally known as thermo- or fluid-dynamics and is covered by several other texts on wikibooks.

The primary purpose of neutronics, is the study and description of the characteristics and distribution of the neutron population within a given volume or system. Because the neutron population is so large, and because calculations and measurements are so crude, this group of particles is generally described in terms of a continuous vector field. This means that calculations in nuclear engineering give values in terms of the average number of neutrons.