Identification of characteristics which influence repository design: tuff. Final report (Task 1), June 1981-March 1982

The purpose of the complete project is to provide NRC with technical assistance to enable the focused, adequate review by NRC of the aspects related to design and construction of an underground test facility and final geologic repository as presented by the Department of Energy (DOE). The study presented in this report covers the identification of characteristics which influence design and construction of a geologic repository in tuff at the Nevada Test Site (NTS). This report has identified five key issues, i.e., constructibility, thermal response, mechanical response, hydrological response, and geochemical response. This report involves both short-term (up to closure) and long-term (post closure) effects. The characteristics of tuff and its environment are described under the headings of stratigraphic/structual tectonic, mechanical, thermal and hydrologic. Characteristics are separated into parameters (quantified and measured) and factors (qualitative). The characteristics are then subjectively ranked by their influence on the key issues. This ranking took into account availability and suitability of conservative design/construction techniques, uncertainty in model and the model sensitivity to characteristics. 65 references, 39 figures, 13 tables