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[en] The purpose of this paper is to determine the behavior of two fuel experimental elements (EC1 and EC2), by destructive post-irradiation examination. The fuel elements were mounted inside a pattern port, one in extension of the other and irradiated in power ramp conditions in order to check their behavior. Fuel element 1 (EC1) contains (UTh)O''2 pellet, and other one (EC2) UO''2 pellet. The results of destructive post-irradiation examination are evidenced by metallographic and ceramographic analyses. The data obtained from the post-irradiation examinations are used, first to confirm the security, reliability and nuclear fuel performance, and second, for the development of CANDU fuel. The results obtained by destructive examinations regarding the integrity, sheath hydrating and oxidation as well as the structural modifications are typical for fuel elements tested in power ramp conditions. (authors)
[en] EUROFER is a 9Cr-1W-0.2V-0.1Ta reduced activation ferritic/martensitic (RAFM) steel, presently considered within the European Union as the primary candidate structural material in a fusion power plant. Its mechanical strength properties currently prevent its use at temperatures higher than 500-550 degrees Celsius. In an effort to extend the range of operating temperatures to 600-650 degrees Celsius and therefore enhance the efficiency of the machine, a different production route, Oxide Dispersion Strengthening (ODS), is being investigated. The characteristics of different versions of EUROFER ODS have been assessed in recent years, leading to the improvement of the material by a combination of optimized production process and post-thermal treatment. Until recently, the mechanical properties of EUROFER ODS had only been investigated in the unirradiated condition, and no information was available for the irradiation response of the material. However, mechanical samples have been irradiated during 2004-2005 at 300 degrees Celsius in the Belgian Reactor 2 (BR2) in Mol to an accumulated dose of 1.73 dpa; tensile, Charpy impact and fracture toughness tests have been performed in the hot cell laboratories of the Belgian Nuclear Centre (SCK-CEN). Metallographic and microstructural investigations were also performed on the investigated material in both the unirradiated and irradiated condition.
[en] The Post-Irradiation Examination Laboratory activities include the decontamination of expensive equipment of different sizes and weight, involving the complexity and extension of the necessary decontamination. A decontamination section has been designed for that purpose. (author)
[en] Calculations of fuel swelling of U3SiAl-Al and U3Si2 were performed for various dispersion fuel element designs. Breakaway swelling criteria in the form of critical fuel volume fractions were derived with data obtained from U3SiAl-Al plate irradiations. The results of the analysis show that rod-type elements remain well below the pillowing threshold. However, tubular fuel elements, which behave essentially like plates, will likely develop pillows or blisters at around 90% 235U burnup. The U3Si2-Al compounds demonstrate stable swelling behavior throughout the entire burnup range for all fuel element designs
[en] The Nuclear Science User Facilities (NSUF) are part of a growing number of Department of Energy user facilities in the U.S., and is the only national designated nuclear energy user facility. Through a peer-reviewed proposal process, NSUF provides external research teams cost-free access to reactor, post-irradiation examination (PIE) and beamline capabilities at Idaho National Laboratory (INL) and a diverse mix of affiliated partner institutions at universities, national laboratories and industry facilities located across the country.
[en] Computed tomography (CT) has been recognised by the medical profession for 20 years as a powerful non-destructive, non-invasive technique for producing detailed cross-sectional images. It is only in the last decade, however, that it has been acknowledged for industrial applications. The work of a small research team at Harwell is described which aims to identify applications within the nuclear industry. (author)
[en] This paper describes the first major contract awarded to private industry to carry out decommissioning of a facility with significant radiation levels. The work required operatives to work in pressurised suits, entry times were significantly affected by sources of radiation in the Caves, being as low as thirty minutes per day initially. The Caves at Berkeley Nuclear Laboratories carry out post irradiation examination of fuel elements support units and reactor core components from CEGB power stations. The decommissioning work is part of an overall refurbishment of the facility to allow the receipt of AGR Fuel Stringer Component direct from power stations. The paper describes the decommissioning and decontamination of the facility from the remote removal and clean up work carried out by the client to the hands-on work. It includes reference to entry times, work patterns, interfaces with the client and the operations of the laboratory. Details of a specially adapted size reduction method are given. (Author)
[en] This longitudinal clinical investigation was undertaken to find out the effect of denture wearing habit (day versus day and night), denture hygiene and cigarette smoking habit on the frequency of denture induced stomatitis. Comparisons were made between 240 complete denture wearers, half of whom were asked to wear their dentures at the daytime only and the other half to wear the denture day and night. All these participants were male patients with a mean age of 57.6 years who had received maxillary complete acrylic dentures for the first time. Fifty percent of the samples were smokers. A standard method for examination of the mouth and denture construction, insertion and follow up were employed. Putative risk factors (denture wearing habits, denture hygiene and smoking) were investigated. Subjects were recalled 12 months after insertion to examine the quality of the denture and the condition of the maxillary mucosa. No significant correlation was found between deterioration of stability or occlusion and type of habitual use of the dentures (P > 0.05). Fourteen percent of the cases reported with inflamed maxillary mucosa. Deterioration of retention or occlusion separately showed no correlation with the condition of the mucosa. However, associated deterioration of both stability and occlusion proved to be significantly correlated with the occurrence of denture stomatitis (P < 0.05). Denture stomatitis was significantly more frequently with subjects wearing their dentures overnight compared with those who removed them (P < 0.05). A significant correlation was also found between cigarette smoking, poor oral hygiene and the presence of denture induced stomatitis (P < 0.05). Nocturnal denture wearing habit, deficient oral and denture hygiene, and cigarette smoking are all important predisposing factors to denture-induced stomatitis, however, none of these factors was the sole cause of mucosal inflammation. (author)
[en] The problems studying complex material testing of experimental fuel elements are considered. Parameter pre-reactor classification is shown to be the necessary part of such studies, because only in comparative analysis of the information received in the course of pre-reactor control and post-reactor investigations, it is possible to increase the estimation accuracy of fuel element ''viability'' limits. Problems connected with reception, storage and processing of the proper information are discussed. Recommendations on methodologic and metrologic supply of studies are given