Preliminary one-dimensional thermal analysis of waste emplacement in tuffs

Abstract

One-dimensional calculations of neai-field temperatures resulting from waste emplacement in a multiple-layered tuff stratigraphy are presented.Results indicate a marked sensitivity of peak temper atures tu assignment of in-situ fluid pressure, geothermal-heat flux, waste type, and location of waste relative to a specific stratigraphic discontinuity.Under the criterion that allowable initialpower densities are limited by the occurrence of boiling at a distance of 10 m from '.unplaced wsste, allowable power densities are calculated to range up to 150 kW/acre or more, depending upon geotherrnal heat flux and waste type. CONTENTS

Thermal impact of waste emplacement and surface cooling associated with geologic disposal of high-level nuclear waste

“…shale (Thomas and others 1981). tuff (Bulmer and Lappin 1980;see ~lso SNL 1986). and alluvium (Smyth and others 1979).…”

Appraisal of nuclear waste isolation in the vadose zone in arid and semiarid regions (with emphasis on the Nevada Test Site)

“…The unsaturated zones in alluvium and tuff are among the environments being considered for a nuclear waste repository. Within the Great Basin/ including the Nevada Test Site (NTS), valleys with alluvial thicknesses of up to 600 m {Smyth et al«, 1979) and stratified tuff formations at depths greater than 700 m (Bulmer and Lappin, 1980) are being evaluated as repository sites. The suitability of these rock types to dissipate the waste heat is an important consideration in the evaluation.…”

“…The National Waste Terminal Storage Program has considered an 800-m depth for the reference repository in tuff (Raines et al, 1980). The thermal proper ties represent the Bullfrog Member of Crater Flat Tuff below 711 m, which was encountered in the Yucca Mountain exploratory hole UE25A-1 (Bulmer and Lappin, 1980). The Bullfrog tuff is partially welded and is below the water table.…”

Thermal impact of waste emplacement and surface cooling associated with geologic disposal of nuclear waste

“…* media for the storage of spent fuel and reprocessed HLW. These include the engineer ing design studies of a reprocessed HLW repository in domed salt (Stearns-Roger Engineering Co., 1979), a spent fuel repository in bedded salt (Kaiser Engi neers, 1978a,b), and a spent fuel repository in basalt (Kaiser Engineers et al , 1 980), as well as generic and scoping studies for granite (Lindblom et DOE, 1980a,b (Bulmer and Lappin, 1980), and dry alluvium (Smyth et al, 1979). Reference repository conditions for the first five rock types are currently being developed in a DOE/NWTS study.…”

“…Hydrologic data for tuff and alluvium have also been compiled (Smytn et al , 1979;Tyler, 1979;Bulmer and Lappin, 1980). Table 3.10 lists a typical value and the range for both the permeability and the porosity of the repository host interval or layer of the particular rock type.…”