Canister material

Initially, Oz diffuses through the bentonite and granitic domains, controlling the redox state of the system. Once 02 is exhausted, granitic groundwater controls the redox state of the system. The results of these calculations performed with the PHREEQC geochemical code (Parkhust Appelo 1999) clearly indicate that there is a substantial variability in pH/pe space along the temporal and spatial evolution of the near field of a repositoiy. This has clear consequences for the subsequent interactions with the Fe canister material and finally with the spent fuel matrix. 

The fluids that have evolved as a result of the bentonite-groundwater interactions will contact the canister on their travel towards the spent fuel matrix. Most of the proposed canister materials in different countries have in common the presence of Fe in the system, either as cast iron (Sweden, Finland) or as stainless steel (France, Spain). While the bentonite-groundwater processes have... 

Judging from this, the concept of deep geological storage of spent nuclear fuel in copper coated steel canisters would appear to be an inherently safe solution where the canister material as well as the spent nuclear fuel itself provide conditions for self-healing upon canister failure. 

Thermal expansion has to be looked on under one more aspect. Different expansion coefflcients of glass and canister material may cause stress in the canister wall. It has been observed that this may signiflcantly promote corrosion of the canister. 

It should be noted that the canister may add considerably to the durability of a high-level radioactive waste package. Often it may be easier to achieve a higji degree of sophistication with a nonradioactive canister material than with a highly radioactive solidification product. 

The durability of the canister material also poses a problem. At present, the favoured material is stainless steel. The conditions that the canister must tolerate include temperatures of up to 200 C, water vapour, water, and corrosion products from the immobilising solid. The time-scale of thousands of years increases the durability problem enormously. Additionally, the presence of other metallic elements, both inside and outside of the container, can lead to electrochemical corrosion. 

The canister materials and welds are performed under an NRC approved quality assurance program. 

States made it desirable to find better canister materials. The first attack on the problem was on the absorbents, and NDRC contracts were set up for fundamental studies at the University of Illinois, at Johns Hopkins University, and at Northwestern University. ... 

Most of the above apphcations are in clarification duties. The use of HGMS to dewater relatively concentrated, paramagnetic mineral slurries has been demonstrated on 2 to 12 wt % feed concentration of synthetic malachite (7) concentrated to 40%. The magnetic collection was optimized at flow velocities of 1 mm/s, and product concentrations greater than 40% were not possible unless the collected material could be removed from the matrix with less than the equivalent of one canister of washwater. 

The vapor vent valves are connected to the tank vapor control valve, and ultimately to the carbon canister by tubing that is resistant to swelling in the presence of fuel vapors. The tubing material must also have a low HC permeation rate, so that the evaporative emissions are not increased due to release of HC molecules. The tank vapor control valve connects the carbon canister to two fuel tank vapor sources the vapor vent valve lines and a refueling vent tube. 

A major challenge in providing electrical power for implantable devices is the isolation of toxic or bio-incompatible materials. As the size of the device decreases to a centimeter or millimeter scale, the parts responsible for isolation, such as canisters and seals, begin to determine the size of the device. An alternative is to design an electrochemical system that is compatible with the physiological environment and can take advantage of chemical species available in that environment, specifically the... 

The 239j240pu can (je accounted for as being from nuclear weapons-produced fallout over the past 30 years, and not from the waste disposal canisters. The mechanism must be by transport and redistribution of the fine floculent sediment at the sediment-water interface. Because of the significant amount of sediment which is being transported down-canyon, any leakage from the canisters would probably be scavenged locally by the environmental sediment material. 

Materials safety glasses, Alka-Seltzer tablets, 35 mm film canisters (the white Fuji brand ones work better than the black ones), aluminum pie pan, water... 

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