[en] This invention concerns the plant and chemical processes and in particular a plant and processes where the atmosphere is contained and continually placed in close circuit flow. Such a plant can be used for processes where the atmosphere of the plant must be prevented from going outside, such as in the case of a plant processing nuclear fuel, like a plant in which irradiated nuclear fuels are reprocessed or in which fuels containing plutonium are made

[en] Several types of clean rooms are commonly in use. They include the conventional clean room, the horizontal laminar flow clean room, the vertical laminar flow clean room and a fourth type that incorporates ideas from the previous types and is known as a clean air bench or hood. These clean rooms are briefly described. The origin of contamination and methods for controlling the contamination are discussed

[en] This paper describes the process of defining technical requirements for a major Department of Energy Research and Development Facility and subsequent development of construction specifications for the clean spaces in that facility. The organizational interactions between technical client, Engineering and Construction elements are described. The importance of an interdisciplinary team approach is stressed. A brief description of the SHIVA Laser and NOVA Laser Clean Spaces is included to indicate the scope of the facility undertaking. A number of potential pitfalls are discussed that may be helpful to designers of new facilities

[en] The specification relates to the general design and installation of electrical services required in unshielded glove boxes in which atmospheres of air, argon or nitrogen etc. may exist either temporarily or permanently. The specification does not apply to electrical services for glove boxes with flammable explosive atmospheres. (author)

[en] In the gas main are placed 2 series of specific gas purifiers in parallel. Pressure is controlled with a buffer tank two three way solenoid value upstream and down stream a compressor and a supercharger. A checking board allows continuous monitoring of circuit tightness

[en] Highlights: • Flexible, experimentally validated scale formation model for two different steels. • Scale formation kinetics for air-fuel, oxygen enriched and oxy-fuel combustion. • Prediction of local and temporal scale formation rates during steel reheating. • Local oxidizing species at steel surface determine the scale formation kinetics. • Oxy-fuel combustion decreased reheating time and lowered scale losses. This work presents a geometry-flexible, spatially resolved scale formation model for a mild and a tempering steel in high temperature reheating furnaces. Corresponding oxidation kinetics in air-fuel, oxygen enriched and oxy-fuel combustion atmospheres were developed to predict scale layer formation rates with high resolution in time and space. The results demonstrate the influence of different combustion atmospheres on the scale formation behaviour and highlight the local effects of oxidizing species. Finally, it was shown that oxygen enhanced and oxy-fuel combustion can be effectively used in reheating furnaces to minimize material losses, increase both productivity and efficiency and simultaneously reduce costs.

[en] The process described is for the hot assembly of similar or dissimilar metallic, non-metallic or partially metallic components, without direct contact with a cleaning flux by means of a weld metal or alloy having a melting point lower than that of the most easily melted component. The components to be assembled as well as the weld metal or alloy are brought to a temperature equal at least to that causing the weld metal or alloy to melt, in an enclosure substantially empty of air and containing one or several free or combined halogens of which at least a proportion is in a gaseous state, or passes into it, during at least part of the heating time

[en] The invention concerns the flushing gas supply equipment for a nuclear reactor, particularly the incoming pipework in the containment lid of the reactor vessel. Pipework connections across the plane of separation of the supporting ring construction and beyond the rotating sealing plates are avoided by using the plane of separation as connections. All constructional details are described extensively. (UWI)

[en] Uraninite is the most common uranium mineral, which, because of chemical and structural similarities to synthetic UO₂, is a useful natural analogue for UO₂ in spent fuel. Uraninite, however, contains 'impurities' such as Pb, Ca, Si, U⁶⁺, Th, Zr, and lanthanides. These affect the thermodynamic properties of uraninite, the rate of uraninite alteration, and the composition of the corrosion products. Uraninite can contain a significant amount of radiogenic Pb, and the Pb-uranyl oxide hydrates (Pb-UOH) are the most common corrosion products formed by the oxidative alteration of Pb-bearing uraninites. Incongruent alteration of the Pb-UOHs in natural waters produces increasingly Pb-enriched uranyl phases, effectively reducing the amount of U lost from the corrosion rind. This is not true of other uranyl oxide hydrates, such as schoepite, UO₃ x 2H₂O, or becquerelite, CaU₆O₁₉ x 11H₂O, which can dissolve completely under similar geochemical conditions. The most common end product of Pb-UOH alteration is curite. Curite may provide surface nucleation sites for certain uranyl phosphates, thereby enhancing their formation. Uranyl phosphates are generally less soluble than other uranyl phases. In the absence of Pb, schoepite and becquerelite are the common initial corrosion products. The reaction path for the alteration of Pb-free uraninite results in the formation of uranyl silicates, which are generally more soluble than the uranyl phosphates. Thus, the long-term oxidation behavior for ancient, Pb-bearing uraninite is different from young, Pb-free uraninite. (orig./MM)

No abstract available