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Abstract  

At the end of the 1991 Gulf War the U.N. Security Council Resolution called upon IAEA, assisted by the U.N. Special Commission, to carry out inspections of all Iraqi nuclear installations. The IAEA Action Team succeeded in implementing, on very short notice, a comprehensive system of inspection activities, including sampling and analysis at the Agency's Laboratories and other laboratories in Member States. The Agency's Laboratories developed and implemented an analytical strategy with the aim to rapidly and accurately obtain the information necessary for verifying the Iraqi declarations. The analyses ranged from screening for - and /-emitters to accurate determinations of the amounts and isotopic composition of the radionuclides and associated trace elements and compounds. The arsenal of methods included ultra-sensitive radiometric methods, mass spectrometry, neutron activation, X-ray fluorescence and inductively coupled plasma emission spectrometry. Selected results include the detection of uranium chloride compounds, special composition steels, and quantitative accounting of uranium and plutonium production. The selectivity, sensitivity and reliability of the applied analytical techniques in conjunction with validated sampling procedures are essential components of an analytical measurements system that can provide credible results.

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Abstract  

Using gamma-spectrometry systems on mobile units with accurate position information is a convenient means for surveying large areas for radioactive fallout or finding hot spots due to misplaced sources or releases from nuclear installations. Traditionally, large (tens of litres) high efficiency NaI(T1) detectors have been used for the purpose. HPGe detectors, however, offer certain advantages which can often compensate for their lower efficiency. This kind of remote sensing, regardless of detector type, requires specialized software. In order to provide accurate position information, the integration times must be kept as short as possible. This is especially true for fast air-borne measurements where counting periods below one second are desirable. We have constructed a special version of SAMPO software which controls data acquisition and runs real-time gamma-spectrum analysis including peak determination, nuclide identification, activity calculations, and reporting. The measurement/analysis cycle can be reduced down to 0.5 seconds on a standard Pentium-based PC. The analysis results are combined with accurate co-ordinates from a differential GPS system on a color coded map. The system is also able to give alarms based on different criteria. We have already measured and analyzed more than 500 000 spectra in field applications using jets, helicopters, cars, and also on-foot.

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Abstract  

South Africa signed and ratified the Comprehensive Nuclear Test-Ban-Treaty (CTBT) and accordingly made commitments to the Organization (CTBTO). Of the obligations are the establishment of a Radionuclide Laboratory, the design, installation and operation and maintenance of a radionuclide particulate and noble-gas monitoring station and the nomination of one radionuclide specialist South African to serve on an international team for On-Site Inspection (OSI). The last to provide expertise when the worldwide monitoring network provides strong indications that an illegal nuclear test has been performed at the territory of a State Party. The inspection team will be equipped with amongst others radiation monitors and nuclide specific measuring equipment limited to report on specific radionuclides agreed upon by all State Parties. In real-time operational circumstances one may assume that all members of the team will not be registered radiation workers and accordingly be regarded as members of the public when radiation hazard is to be evaluated. In this paper we try to categorize the radionuclides of interest and evaluate the radiological risk to the OSI-team due to inhalation of airborne radioactive particulate matter during the survey at the site of an anticipated nuclear test. From this study recommendations will be made to the CTBTO for possible implementation of portable sampling and analysis equipment to allow on-site evaluation of the potential internal exposure of OSI-team members.

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In conjunction with its 30th anniversary in 2009 the Sóstó Museum Village examined the question of how to move forward. The best solution appears to be to take two directions: on the one hand, strengthening of the professional standard can bring renewal by transferring to the museum types of buildings or installations that have a curiosity value arousing the public’s interest (brandy distillery, soda-water plant, photographic studio, etc.), and on the other hand, strengthening our educational efforts, providing attractions for the public. We had thought that with the implementation of our building transfer plan the construction of the museum village could be regarded as completed, but we found that this was a mistake: there is no such thing as a completed museum, we are constantly faced with new challenges and we can only meet the expectations of the public by strengthening education and entertainment, expanding themes and complex services, and it is only in this way that we can provide a greater feeling of comfort for visitors. But in achieving this we must take care to avoid the danger of commercialisation and the “Disneyland“ effect. The article is about the attainment of this goal.

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Abstract  

Materials of significant inhomogeneity require big samples to be analyzed. With the exception of very few installations worldwide the near-core neutron irradiation positions are not spacious enough to fulfil this condition. The use of beam geometry activation analysis (BEAMGAA) has actually turned out to be an alternative as the activities obtained are proportional to the product of flux and sample mass. In the case of hard photon radiation delivered by the 30 MeV-Linac of BAM, equipped with a programmable scanner of the electron beam for dose equalization, a nearly uniform distribution could be obtained in a volume of 7 cm×7 cm×2 cm. It is shown that big sample volumes up to 7 cm×7 cm×10 cm can be treated and non-linearities of irradiation can be perfectly taken into account by the self-adjusting method of consecutive correction factors (COCOFA). Nevertheless, the concept of “sliced samples” has to be considered when maximum correctness of the analytical results has to be guaranteed. With the measures described in photon activation analysis a quality level was realized which was not reached hitherto.

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Abstract  

The British Nuclear Fuels Limited (BNFL) complex (Sellafield) in Cumbria discharges into the atmosphere, under authorization by the Environment Agency (and previously, the Ministry of Agriculture, Fisheries and Food (MAFF), radioactive waste consisting of gases, mists and dusts. As part of MAFF's radiological surveillance programme, the intake of radionuclides via food ingestion by members of the public living near this nuclear installation is routinely assessed from measurements made on local food and environmental samples and by using computer models simulating the dispersion and incorporation of radioactivity into foodstuffs. In this study, the individual diets of adults and children living near the Sellafield complex and those from a control group were assessed for their radionuclide content. The participants were selected via a food survey questionnaire which was aimed at identifying those who consume home grown fruits and vegetables or derive these from local sources. The diets were collected over a one-week period in August 1995 and following radiochemical analyses of the diets for239+240Pu,137Cs,90Sr,14C, and129I, the doses received by the participants from these nuclides were extrapolated over a one-year period and compared to doses calculated from food surveillance data and to doses predicted using the MAFF food-chain computer model.

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Abstract  

Gas and oil companies frequently encounter build up of Naturally Occurring Radioactive Material (NORM) in their production and processing facilities. In the Netherlands NORM is subject to strict national regulations and, consequently, installations have to be screened on a regular basis. The availability of accurate and reliable NORM sampling and analysis techniques is therefore essential. A number of years ago, the Nederlandse Aardolie Maatschappij B.V. (NAM) actively initiated an investigation on analysis techniques for NORM samples from gas and oil companies. Within this framework, Shell Research Amsterdam organized a four-stage interlaboratory test programme in which representative samples of increasing complexity were analyzed by a number of Dutch institutes. Whereas a large spread in results was observed in the first stage, results in the last stage deviated less than ±10% from the values certified by an independent referee institute, even for comple, sludge samples. It was found that in particular the use of different values for the -yields and branching ratios amongst the institutes was responsible for the initial spread.

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Abstract  

Colloids play a major role in the transport of trace metals as well as radionuclides in natural waters. These species are of importance for passive take in biota.Radionuclides may form colloids and pseudocolloids during hydrolysis or through interaction with other components present in the water phase, such as clay minerals or humic substances. Furthermore, aggregation and dispersion and other transformation processes, will influence the colloidal fraction, for instance during storage of samples. Fractionation of radionuclides associated with colloids in natural waters should, therefore, take place in situ or shortly after sampling.Different analytical techniques are useful for the fractionation of colloids, pseudocolloids, and particles. In the present paper, the application of hollow fiber ultrafiltration and dialysis is demonstrated for radionuclides in waste waters from the Oscarshamn nuclear installation in Sweden.The results illustrate that hollow fiber ultrafiltration is a more powerful technique than dialysis. The fractionation is rapid, sorption is of minor significance, the pore size distribution is rather narrow, and the filtering capacity is high.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: H. Biggin, N. Chen, K. Ettinger, J. Fremlin, W. Morgan, R. Nowotny, M. Chamberlain, and T. Harvey

Résumé  

On peut déterminer la présence de cadmium chez l'homme à l'aide de technique de l'analyse par activation neutronique in vivo. La capture des neutrons thermiques par113Cd conduit à une émission γ prompt qui peut être détectée au moyen d'un semi-conducteur convenable. On a réalisé une installation à l'Université de Birmingham pour produire au moyen d'un cyclotron un faisceau de neutrons pulsés. Une série d'expérience a été faites sur des cadavres; ces expériences ont prouvé qu'il est possible de détecter le cadmium à une concentration de 2,0 ppm dans le volume d'un foie humain pour une dose de 1 rem. On discute des résultats et des applications possibles de cette étude.

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Performance validation of step-isothermal calorimeters

Application of a test and reference reaction

Journal of Thermal Analysis and Calorimetry
Authors: B Finnin, M O'Neill, S Gaisford, A Beezer, J Hadgraft, and P Sears

Abstract  

Isothermal calorimetry is becoming indispensable as a tool for the study of a wide variety of systems. As with all scientific instruments it is essential that robust calibration routines be developed in order to validate the data obtained. Chemical test reactions offer many advantages over (the traditionally used) joule effect heating methods, not least because they have the potential to validate instrument performance (i.e. they can be used to assess all aspects of calorimeter operation). In this work the results of a validation exercise, conducted by Thermal Hazard Technology as part of an installation routine, using the base catalysed hydrolysis of methyl paraben are discussed. In the case described, a systematic misreporting of the reported temperature of a calorimeter was identified, caused by an upgrade to the calorimeter's firmware, a discrepancy which may not have been noted using traditional electrical calibration methods and one which highlights the importance of both manufacturers and end-users adopting chemical test reactions into their test and validation routines.

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