[en] The United States Department of Energy (DOE) currently manages the UF, Cylinder Project. The project was formed to maintain and safely manage depleted uranium hexafluoride (UF₆) stored in approximately 50,000 carbon steel cylinders. The cylinders located at three DOE sites: the K-25 site at Oak Ridge, Tennessee (K-25); the Paducah Gaseous Diffusion Plant in Paducah, Kentucky (PGDP), and the Portsmouth Gaseous Diffusion Plant (PORTS) in Portsmouth, Ohio. The System Requirements Document (SRD) (LMES 1997a) delineates the requirements of the project. The appropriate actions needed to fulfill these requirements are then specified within the System Engineering Management Plan (SEMP) (LMES 1997b). The report presented herein documents activities that in whole or in part satisfy specific requirements and actions stated in the UF₆ Cylinder Project SRD and SEMP with respect to forecasting cylinder conditions. The wall thickness projections made in this report are based on the assumption that the corrosion trends noted will continue. Some activities planned may substantially reduce the rate of corrosion, in which case the results presented here are conservative. The results presented here are intended to supercede and enlarge the scope of those presented previously (Lyon 1995,1996, 1997). In particular, projections are made for thin-walled cylinders (nominal initial thickness 312.5 mils) and thick-walled cylinders (nominal initial thickness 625 mils). In addition, a preliminary analysis is conducted for the minimum thickness at the head/skirt interface for skirted cylinders

[en] The optimum choice of all the internal characteristics of a gaseous diffusion plant for minimizing the enrichment cost, is a large scale problem. The mathematical analysis of the model simulating such a plant has led to the observation of a hierarchical structure, introducing a method of decomposition. The multi-level approach focuses successively on three levels: the stage, the cascade, the plant. Then each level can be solved specifically, using an algorithm properly suited to its characteristics. The problem is to coordinate properly the sub-optimizations by using coordination variables. This method has effectively been used for years as a tool for the decision-makers, in association with the experimental and development work, and the industrial analysis, furnishing the current technical and economical data at the moment of the decision: plant capacity, component performances, economical prices and trends

[en] To estimate the economic characteristics of an uranium enrichment plant by gaseous diffusion is to determine the prospective price of the separative work unit to which leads the concerned technology, and to collect the data allowing to ascertain that this price remains in the area of development of the prices forecasted by the other projects. The prospective price estimated by the promoter is the synthesis of the components of the go decision and which are a potential market and a comprehensive industrially proven plant design, including the basic economic and technical data of the project. Procedures for estimating these components and their synthesis, exclusive of financing problems are reviewed

[en] The procedure and organization of a gaseous diffusion plant is reviewed. A general description of the control method used with success for some years is given. It is found that owing the duration of start up operations, the length of transients and the precautions to be taken in the event of stopping, a plant of this kind should be run continuously. However during a period of operation the production can be varied owing to the flexibility of the assembly. The quality of production under permanent running conditions is maintained by the supervision of many parameters and by certain corrective operations and the structure of the assembly must be constant. Random deteriorations of equipment create perturbations of a more or less serious nature, the effects of which must be corrected. For the control, a centralization of the material facilities employed has been adopted

[en] The invention relates to an improvement in a conventional double-disc gate valve having a vertically movable gate assembly including a wedge, spreaders slidably engaged therewith, a valve disc carried by the spreaders. When the gate assembly is lowered to a selected point in the valve casing, the valve discs are moved transversely outward to close inlet and outlet ports in the casing. The valve includes hold-down means for guiding the disc-and-spreader assemblies as they are moved transversely outward and inward. If such valves are operated at relatively high differential pressures, they sometimes jam during opening. Such jamming has been a problem for many years in gate valves used in gaseous diffusion plants for the separation of uranium isotopes. The invention is based on the finding that the above-mentioned jamming results when the outlet disc tilts about its horizontal axis in a certain way during opening of the valve. In accordance with the invention, tilting of the outlet disc is maintained at a tolerable value by providing the disc with a rigid downwardly extending member and by providing the casing with a stop for limiting inward arcuate movement of the member to a preselected value during opening of the valve

[en] Starting and achievment of Eurodif. Situation in 1980

[en] The gaseous diffusion plants are now undergoing a CIP-CUP program with concomitant increased separative work capacity. Welding operations involved in the program are described

[en] This invention relates to sealing devices between a motor component and a receiving component, particularly between a driving device and the rotor of a revolving machine, joined by disconnectable couplings. These devices apply to closing devices that may be used anywhere a leak proof situation must be assured for certain. This is the case of the closures used in uranium enrichment units where, for the purpose of servicing, the power drive and the bearings must be disconnected with causing the compartment containing the compressor and noxious gas to empty

[en] Starting and achievment of Eurodif. Situation in 1980

[en] General methods of judging the endurance properties of materials are presented. The endurance of a material is characterized here by a mathematical concept known as the survival function, determined by the introduction of a model and the definition of certain notions such as the age and death of the material. A point estimate is reached, corresponding to the most probable survival function, and an estimate by confidence limits which assembles the most probable survival functions to a threshold corresponding to the confidence level required. An application at the Pierrelatte plant is described