Underground Corrosion of Activated Metals in an Arid Vadose Zone Environment

The subsurface radioactive disposal site located at the Idaho National Engineering and Environmental Laboratory contains neutron-activated metals from nonfuel nuclear-reactor- core components. A long-term corrosion test is being conducted to obtain site-specific corrosion rates to support efforts to more accurately estimate the transfer of activated elements in an arid vadose zone environment. The tests use nonradioactive metal coupons representing the prominent neutron-activated material buried at the disposal location, namely, Type 304L stainless steel, Type 315L stainless steel, nickel-chromium alloy (UNS NO7718), beryllium, aluminum 6061-T6, and a zirconium alloy, (UNS R60804). In addition, carbon steel (the material presently used in the cask disposal liners and other disposal containers) and a duplex stainless steel (UNS S32550) (the proposed material for the high- integrity disposal containers) are also included in the test program. This paper briefly describes the test program and presents the early corrosion rate results after 1 year and 3 years of underground exposure

Extended Storage for Research and Test Reactor Spent Fuel for 2006 and Beyond

This paper will examine issues associated with extended storage of a variety of spent nuclear fuels. Recent experiences at the Idaho National Engineering and Environmental Laboratory and Hanford sites will be described. Particular attention will be given to storage of damaged or degraded fuel. The first section will address a survey of corrosion experience regarding wet storage of spent nuclear fuel. The second section will examine issues associated with movement from wet to dry storage. This paper also examines technology development needs to support storage and ultimate disposition

Development of Neutron Absorbers to Support Disposal of DOE SNF

The National Spent Nuclear Fuel Program, located at the Idaho National Engineering and Environmental Laboratory, coordinates and integrates national efforts in management and disposal of U.S. Department of Energy (DOE)- owned . These management functions include using the DOE standardized canister for packaging, storage, treatment, transport, and long-term disposal. Nuclear criticality control measures are needed in these canisters because of the enrichment and total quantity of fissile material in some types of the DOE spent nuclear fuel. This paper will report the test results of one alloy heat from a metallurgical development program that is developing nickelchromium- molybdenum-gadolinium alloys for nuclear criticality control in the DOE standardized canister. Gadolinium has been chosen as the neutron absorption alloying element due to its high thermal neutron absorption cross section. The microstructure, mechanical properties, and corrosion resistance of various alloys will be presented. These corrosion resistant, structural alloys can be used to fabricate components of spent nuclear fuel storage racks, storage canisters and internal structural baskets, and transportation cask internals. The focus of this work is to qualify these materials for American Society of Mechanical Engineers code qualification and acceptance in the Yucca Mountain Repository