Authors:Christopher Ryan, Craig Marianno, William Charlton, and William James
The dissolution of the Soviet Union coupled with the growing sophistication of international terror organizations has brought
about a desire to ensure that a sound infrastructure exists to interdict smuggled nuclear material prior to leaving its country
of origin. To combat the threat of nuclear trafficking, radiation portal monitors (RPMs) are deployed around the world to
intercept illicit material while in transit by passively detecting gamma and neutron radiation. Portal monitors in some locations
have reported abnormally high background counts. The higher background data has been attributed, in part, to the naturally
occurring radioactive materials (NORM) in the concrete surrounding the portal monitors. Higher background increases the minimum
detectable activity (MDA) and can ultimately lead to more material passing through the RPMs undetected. This work employed
two different neutron activation analysis (NAA) methods for the purpose of developing a process to characterize the concrete
surrounding the RPMs. Thermal neutron instrumental NAA (INAA) and fast NAA (FNAA) were conducted on six samples from three
different composition concrete slabs. Comparator standards and quality control materials were used to help ensure that the
methods were both precise and accurate. The combination of INAA and FNAA accounted for 84–100% of the total elemental composition
of the samples. Knowing the composition of the concrete will allow RPM customers to choose suitable materials prior to installation,
thereby increasing the ability of the monitors to detect radiological and nuclear materials.
Authors:B Finnin, M O'Neill, S Gaisford, A Beezer, J Hadgraft, and P Sears
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
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.
Authors:A. Sanchez, D. Singleton, B. Walters, and J. Cobb
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.
Authors:W. Knaepen, W. Bergwerf, P. Lancée, W. Van Dijk, J. Jansen, R. Janssen, W. Kiezenberg, R. Van Sluijs, M. Tijsmans, K. Volkers, and P. Voors
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.
Bastianini, F. – Rizzo, A. – Galati, N. – Deza, U. – Nanni, A.: Discontinuous Brillouin strain monitoring of small concrete bridges: Comparison between near-to-surface and „smart” FRP fiber installation techniques. Proceedings of SPIE – The International
Geothermal energy is the most economical of the green energy resources such as solar or wind. It is a ‘base-load’ type of power, which is constantly available, not just when the sun shines or the wind blows. In Hungary, geothermal energy has proven to be an economical source of energy for direct use. A significant amount of geothermal energy is located throughout Hungary and thermal water (> 30 °C) can be found over 70% of the area of the country. This is supplied mainly from two principal aquifer systems of regional extent. One of them is the clastic Upper Pannonian Quaternary fill of the Pannonian basin, and the other one is the fractured and/or karstified Mesozoic basement. The geothermal situation in Hungary offers two directions for the utilization of geothermal energy. Using the heat from shallow geological sections for heating and cooling buildings; and using thermal sources of low enthalpy thermal waters in several ways (heating and sanitary waters in buildings, greenhouses and aquaculture installations). The potential of geothermal resources and their immediate development should focus on cascade and integrated utilization of geothermal energy. Cascade schemes should be used to fulfil the thermal energy demand for the selected area in order to get the maximum benefit from geothermal energy with the minimum energy demand from heat pumps. The integrated scheme has environmental benefits by using renewable energies (geothermal energy and solar energy), new technologies (heat pumps) and energy savings (cascade scheme). In the long-run, the economic benefits of geothermal power may even exceed those of the fossil fuels. It would likely prove to be a sustainable low-cost source of power. Exploitation of geothermal energy will have a direct impact on the development of the regions, by increasing per capita income and at the same time raising the inhabitants’ standard of living.
A kutatás alapja az a feltételezés, hogy a paneles lakótelepek komplex megújítása városépítészeti léptéket követel, melyben az épületek földszintjei, a külső és belső térkapcsolatok újraértelmezése kiemelt fontosságú. A problémakör feltárása a hazai nagypaneles épületek földszintjeinek építészeti kialakítására épül. A cikk a rendelkezésre álló katalógusok alapján egyrészt a talajközeli térhatár (zárt, áttetsző vagy árkádos), másrészt a nyílások (bejárati ajtó, lakásablak, erkély, kapu, kirakat, közös tér ablaka, gépészeti nyílás, átjáró) tipológiáját állítja fel. Ezt a lakó és látogató számára fontos alsó szintet — a tömegterméket, a paneleket tartó, viszonylag sokféle, az adott helyhez is alkalmazkodó fundamentumot — nemcsak a panelházak építési korában, de az elmúlt évtizedek felújításai során is elhanyagolták. A műszaki vagy látványmegoldások alig érintik, így az épített környezetből a használatot terhelő problémák, mint például a rossz szubjektív biztonságérzet, a találkozások tereinek kerülése, az alulhasznosítottság stb. megmaradnak. Az írás a panelföldszintek építészeti megoldásainak összefoglalását adja, rávilágít az ezekből adódó használati problémákra, felhívja a figyelmet a témakör kiemelt kezelésének fontosságára.
Authors:D. Das, Sumit Kumar, P. Pathak, B. Tomar, and V. Manchanda
Release of long-lived radioactivity to the aquatic bodies from various nuclear fuel cycle related operations is of great environmental
concern in view of their possible migration into biosphere. This migration is significantly influenced by various factors
such as pH, complexing ions present in aquatic environment and sorption of species involving radionuclides on the sediments
around the water bodies. 241/243Am are two major radionuclides which can contribute a great deal to radioactivity for several thousand years. In the present
study, 241Am sorption on natural sediment collected from site near a nuclear installation in India, has been investigated under the
varying conditions of pH (3–10) and ionic strength [I = 0.01–1 M (NaClO4)]. The sorption of Am increased with pH of the aqueous medium [10% (pH 2) to ~100% (pH 10)], which was explained in terms
of the increased negative surface charge on the sediment particles. There was marginal variation in Am(III) sorption with
increased ionic strength (within error limits) of the aqueous medium suggesting inner-sphere complexation/sorption process.
Sediment was characterized for its elemental composition and structural phases using Energy Dispersive X-Ray (SEM-EDX) and
X-Ray Diffraction (XRD) techniques. Zeta-potential measurement at I = 0.1 M (NaClO4) suggested that Point of Zero Charge (pHPZC) was ~2, indicating the presence of silica as major component in the sediment. Kurabtov plot using sorption data as a function
of pH at fixed I = 0.1 M (NaClO4) indicated the presence of multiple Am(III) species present on the surface. Potentiometric titration of the suspension indicated
the presence of mineral oxide like behavior and assuming a generic nature (≡XOH) for all types of surface sites, protonation–deprotonation
constants and total number of sites have been obtained. The sorption data has been modeled using 2-pK Diffuse Double Layer
Surface Complexation Model (DDL-SCM). ≡XOAm2+ has been identified as the main species responsible for the sorption profile.