Dosimetry method for light water reactors

In multiple foil dosimetry a combination of fission and non-fission monitors is used for materials irradiation in reactors. Each monitor is sensitive to different neutron energy ranges, and increased accuracy in the resultant flux density spectrum is achieved by the use of monitors that collectively embrace the entire significant energy range. This report describes a neutron dosimetry method for light water reactor irradiation experiments. Included in this description are the methods, procedures, and special handling designs which have been developed at G.E.-Vallecitos to assist the experimenter in the planning and design of the dosimeter portion of his experiment for characterizing the neutron environment. Pre-irradiation planning and procedures are described along with monitor selection, preparation, and an encapsulation method using quartz seeds. Cadmium oxide-copper tubes have been fabricated to successfully serve as thermal neutron shields. In some cases, miniaturization of dosimetry materials is necessary to cope with space limitations and to avoid flux gradients. Post-irradiation procedures for handling and analysis of the dosimeters are described. Radioanalysis of all dosimeters is performed by direct counting obviating chemical procedures. Cross-section problems, including integral comparison, are discussed