An overview of the current status of resonance theory in reactor physics application

The key issue of the resonance treatment in reactor applications is directly associated with the use of the microscopic cross sections in the macroscopic reactor cells with a wide range of composition, temperature and geometric configurations which gives rise to the so called self-shielding effect. It can be regarded as the most complicated problem in neutron physics, which requires the dependence of many physical variables. The current papers presents a rather subjective overview on the two important elements of particular interest are discussed from both historical as well as the state-of-art perspectives: 1) a concise description of the resonance cross sections as a function of energy and temperature and 2) accurate estimation of the corresponding neutron flux where appropriate. For the past decades, there have been significant advances in all areas pertinent to this intriguing subjects. These include the improvements on our better understanding of the basic theories, our capabilities of dealing with extremely complex problems and the quality of resonance data. Three general areas are still limited to infinite-repeated reactor lattices based on the 1-dimensional cell configuration at the resonance level. Further exploration into the feasibility of treating the problems in multi-dimensional geometries will undoubtedly be of some practical interest. Secondly, extensive bench-mark studies to verify our ability to predict the self-shielding effect and its associated Doppler-effect are apparently lacking. One idea place to begin is to utilize the existing results of various transmission and self-indication measurements. Thirdly, the statistical theory for treating the unresolved resonances is also worthy of further exploration. 2 figs., 33 refs.(orig.)