Preclosure analysis of conceptual waste package designs for a nuclear waste repository in tuff

Abstract

DISCLAIMERThie report wee prepared u an account of work tponeond by an agency of the UsJted SUM Government Netthw the Uaited Sutaa Oonmment swr any aneocy thereof, nor any of their iwHcyin, makae any warranty, txpreM or implied, or ajramei any legal liability or tatsontieiifcy for the aonracy, completeneM, or HHMMI of any infornation, appantw, product, or prooe* djedoeed, or reprmati that iti ma would not infringe privately owned rithu. Refer ence herein to any apeeiffc commercial product, proowi, or aervice by trade name, trademark, BtaMfactarer, or otherwiee doei not aeceewrily eonttitute or imply itt endonement, recommendatioe, or favoriat by the United Sutaa Oovernmaat or any agency thereof. Vx> viewi awl opinion* of authon eupmeed herein do not neceeserily Mate or reflect tboee of the United Statu Gwei-int or any anency thereof. LAWRENCE LIVERMORE NATIONAL LABORATORY Executive tUnder the direction of the Office of Civilian Radioactive Waste Management, the Department of Energy's (DOE) Nevada Nuclear Waste Storage Investigations (NNWSI) project is evaluating a candidate repository site at Yucca Mountain, Ne vada, for permanent disposal of high level nuclear waste. The Lawrence Livermore National Labora tory (LLNL), a participant in the NNWSI project, is developing waste package designs to meet NRC requirements. Included are designs for the refer ence waste form configurations of: (1) spent fuel (SF), which consists of both consolidated and un consolidated spent fuel rods from pressurizedwater-reactor (PWR) and boiling-water-reactor (BWR) assemblies, (2) commercial high level waste (CHLW), as a borosilicate glass containing commercial spent fuel reprocessing wastes, and (3) West Valley/defense high level waste (WV/ DHIW) immobilized in borosilicate glass. Refer ence and alternative package designs have been developed for each waste form for both vertical and horizontal emplacement configurations. All designs are for emplacement in a tuff repository located above the water table (in the vadose zone).Conceptual designs and analyses for waste packages in tuff below the water table were devel oped for the Office of Nuclear Waste Isolation Summary (ONWI) by Westinghouse Electric Corporation in 1981 -82 (Westinghouse, 1983. The candidate hori zon was changed by NNWSI to the vadose zone in late 1982 (Vieth, 1982;Dudley and Erdal, 1982). LLNL has made changes in and additions to the conceptual designs to reflect this change in the re pository location. Analyses have been performed to determine conformance of the selected design ensemble to NRC design requirements in the cur rently understood repository environment. Fig ure 1 shows the reference conceptual designs. The selected designs (Gregg and O'Neal, 1983) include reference and alternative designs that vary in com plexity, performance, and cost.From this ensemble, one set of designs (for SF, CHLW, and WV/DHIW) will be chosen which is expected to meet Nuclear Regulatory Commission (NRC)/Environmental Protection Agency (EPA) requirements when analyzed with accura...

Volume II: near-field and altered-zone environment report

“…Emplacement of the waste containers will cause an immediate and rapid increase in temperature in the walls of the excavations. The maximum temperature reached will depend on the nature of the waste emplaced and the repository design, but temperatures as high as 230 'C are predicted (ONeal et al, 1984). The thermal loading will affect the stress, strength, and other properties of the rock near the excavations.…”

Corrosion of Copper-Based Materials in Irradiated Moist air Systems

“…Based on thermal calculations published by the YMP [7], relative humidities will not exceed 20!! during the time that gamma radiation levels outside the container are significant (first 300 y).…”

Container Materials for High-Level Nuclear Waste at the Proposed Yucca Mountain Site

“…For instance the bottom of the container and the lid may be thicker than the cylindrical body of the container. Loads imparted during the handling operations are probably the highest that the container will encounter, and the resulting stress will be concentrated in the "neck" of the container [2]. The contoured container shape and thicker section in this area will help to distribute the stress.…”

“…Thus, for mechanical and chemical considerations, thin-walled containers fabricated fror" corrosion-resistant materials have been emphasized in the development of waste package designs for the Yucca Mountain repository. Background on container design can be found in the 1984 Conceptual Design report [2].…”