No abstract available

[en] Chromium gettering has been proven to be a trouble-free and efficient method of surface pumping in tokamaks. The impurity control capabilities are excellent and comparable to that of titanium. The hydrogen uptake is reduced to monolayer quantities on the surface. The expansion of the operating space is similar to that seen with titanium without the disadvantage of strongly increased hydrogen fluxes. Possible applications of chromium gettering are: impurity control in contemporary tokamaks; surface pumping in short pulse DT-burning devices to minimize tritium inventory, and wall-conditioning of future large machines prior to operation. (orig.)

[en] Design and fabrication techniques are described for the manufacture of large-capacity chromium getter sources, analogous to the commercially available titanium getter source known as Ti-Ball, manufactured by Varian Associates

[en] A nuclear fuel element for use in the core of a nuclear reactor is disclosed and has disposed therein an improved getter capable of gettering reactive gases including a source of hydrogen. The getter comprises a composite with a substrate having thereon a coating capable of gettering reactive gases. The substrate has a greater coefficient of thermal expansion than does the coating, and over a period of time at reactor operating temperatures any protective film on the coating is fractured at various places and fresh portions of the coating are exposed to getter reactive gases. With further passage of time at reactor operating temperatures a fracture of the protective film on the coating will grow into a crack in the coating exposing further portions of the coating capable of gettering reactive gases

[en] The interaction of carbon dioxide and erbium thin films is characterized for temperatures in the region of 300 to 900⁰C and partial pressure of carbon dioxide near 5 x 10^-7 Torr. Dynamic film pumping speeds were measured against a mercury diffusion pump of known pumping speed and conductance. A quadrupole mass spectrometer was used to monitor the carbon dioxide flow which originated from a calibrated leak in the 10^-6 standard cm³/s range. Data reduction was via a dedicated minicomputer with associated printer/plotter. Temperature ramp experiments with thin erbium films indicated a significant reaction above 300⁰C. The reaction was preceded by the desorption of water vapor, hydrogen and nitrogen and/or carbon monoxide from the film surface

[en] In connection with the setting up of an installation for the containment and handling of 10 g tritium, pressure resistant tritium storage vessels which could be heated to 550⁰C, and which had a nominal capacity of 1,9 g and a maximum capacity of 5,7 g tritium, were developed. The report gives, in addition to estimations and calculations, the results of measurements on individual components of the storage vessel and its accessories, together with those on a prototype storage vessel. The measurements carried out with hydrogen showed that under suitably chosen operating conditions, a storage vessel can be loaded in 15 minutes and discharged in 2 1/2 hours (limited by thermal capacity), without any carryover of uranium being observed. Most of the measurements were carried out on the thermal behaviour and flow resistance of the vessel, as well as hydrogenation, dehydrogenation, hydrogen adsorption from helium and isotopic mixture effects. The sensitivity of a calorimetric tritium determination of this prototype storage vessel was determined. (orig./HP)

[en] UHV pumps based on non-evaporable getter coated strips find widespread use in particle accelerators, synchrotron radiation machines and nuclear fusion experimental devices. Depending on the geometric constraints, pressure operation conditions and the foreseen gas loads, optimized getter structures, such as modules and cartridges, can be designed and assembled into a high-efficiency pump. In the present paper, the design and performance of a newly conceived High Capacity Getter Pump (HCGP) based on sintered getter bodies, in the shape of blades instead of strips, is illustrated. The porosity and the specific surface area of the blades and their arrangement in the cartridge have been optimized to significantly increase sorption capacity at a given speed. These pumps are well suited for those applications where a very high gas load is expected during the machine operation. The sintered getter bodies increase surface area and capacity, requiring less frequent reactivation and facilitating greater overall life of the pump. A discussion of the experimental results in terms of sorption speed and capacity for various gases is presented

[en] Research on the acetylene compound 1,4-diphenylbutadiyne is an effort to develop a tritium gas getter that will operate in the presence of air and minimize the formation of water. T₂ adds to the acetylene bond of the getter in the presence of a metal catalyst. The catalyst stimulates the T₂-O₂ reaction as well. The butadiyne compound has shown good reaction efficiency for 300 ppM T₂ in static dry air at room temperature and one atmosphere pressure. Metalacetylene complexes are being synthesized, positioning the metal catalyst atom as close to the triple bond as possible to maximize the organic reaction. Organometallics such as triphenyl phosphine iridium are being investigated as possible regenerative getters for T₂ in air. Gas mixtures as low as 1 ppM T₂ in air will be tested under flow conditions in future work

[en] A uranium gettering bed was cycled between room temperature/zero pressure and 600C/275 psi (D₂) for 210 cycles over a period of 8 months. Metallographic examination of the hardware revealed an acceptable amount of reaction between the uranium and the stainless steel container. This exposure is estimated to represent about ten years of normal use

[en] Preliminary results have shown that hydrogen pumping by chromium is a surface effect. Unlike with titanium, the getter material used in many present day tokamaks, there is no significant diffusion into the bulk. This feature, which would minimize the tritium inventory, makes chromium a viable alternate to titanium gettering for future tokamaks. Additional experiments have been carried out to measure the basic characteristics of chromium films for gases of interest in tokamak research. These gases include deuterium, oxygen and nitrogen. A vacuum system is described which allowed precise control of the test gas, a constant wall temperature and determination of the projected getter surface area. A quadrupole mass spectrometer, rather than simply a total pressure gauge, was utilized to measure the partial pressure of the test gas as well as the residual gas composition in the system. A quartz crystal monitor was used to measure film thickness. Pumping speeds and sticking coefficients are given as a function of surface coverage for each test gas. A comparison will be made with titanium films deposited in the same vacuum system and under similar conditions. (orig.)