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[en] MAXINE is an EXCEL© spreadsheet, which is used to estimate dose to individuals for routine and accidental atmospheric releases of radioactive materials. MAXINE does not contain an atmospheric dispersion model, but rather doses are estimated using air and ground concentrations as input. Minimal input is required to run the program and site specific parameters are used when possible. Complete code description, verification of models, and user’s manual have been included.
[en] Ensemble modeling (EM), the creation of multiple atmospheric simulations for a given time period, has become an essential tool for characterizing uncertainties in model predictions. We explore two novel ensemble modeling techniques: (1) perturbation of model parameters (Adaptive Programming, AP), and (2) data assimilation (Ensemble Kalman Filter, EnKF). The current research is an extension to work from last year and examines transport on a small spatial scale (<100 km) in complex terrain, for more rigorous testing of the ensemble technique. Two different release cases were studied, a coastal release (SF6) and an inland release (Freon) which consisted of two release times. Observations of tracer concentration and meteorology are used to judge the ensemble results. In addition, adaptive grid techniques have been developed to reduce required computing resources for transport calculations. Using a 20- member ensemble, the standard approach generated downwind transport that was quantitatively good for both releases; however, the EnKF method produced additional improvement for the coastal release where the spatial and temporal differences due to interior valley heating lead to the inland movement of the plume. The AP technique showed improvements for both release cases, with more improvement shown in the inland release. This research demonstrated that transport accuracy can be improved when models are adapted to a particular location/time or when important local data is assimilated into the simulation and enhances SRNL's capability in atmospheric transport modeling in support of its current customer base and local site missions, as well as our ability to attract new customers within the intelligence community.
[en] Radium-226 is one of the main natural radionuclides, which is present in the environmental samples such as soil, water, food, etc. In order to assess the transfers and uptakes of 226Ra, the vegetable-to-soil concentration ratio (CR) has been studied in a highly radioactive region of Ramsar. This area is of special interest in the world, due to the presence of several hot springs with high 226Ra concentrations. Concentrations of 226Ra were measured in different types of vegetables and substrate samples, using gamma spectrometry. The results show that the average vegetable-to-soil CR value in leafy vegetables (1.5 x 10-2) is more than root vegetables (4 x 10-3). In fact, uptake of 226Ra via roots of vegetables is directed toward the leaves. In addition, the CR values measured in edible vegetables in a highly radioactive region of Ramsar are similar to those values in low background radiation areas. (author)
[en] A method for 210Pb determination in water samples is described. The nuclide is pre-concentrated on ion-exchanger and then measured via liquid scintillation spectrometry. The efficiency of preconcentration method and of measurement was assigned. The method was tested on several bottled mineral waters
[en] The uptake of radionuclides by aquatic biota is most generally described by the concentration factor CF, which is the ratio of the activity concentration in the organism to activity concentration in the surrounding water. A database on concentration factors for radionuclides selected for consideration in FASSET project in the freshwater environment was developed. CFs illustrate well differences between organisms, but have also shortcomings. Their application is limited in situations where isotopic equilibrium is strongly distorted. (author)
[en] Full text: Depletion of soil nutrients and its adverse effect on the productivity of crops is a major concern in the world today. Micro-nutrient boron plays an important role in the increase of production of crops as well as amino acids, which control the protein contents of the crops. Optimum concentration of boron in soil is essential for the growth and production of crops such as rice, potato, oat, soya bean, tomato, etc. The analysis of boron in soil is important but the conventional methods are usually lengthy and complex and there is always a chance of losing the trace elements in the process. In the present study proton induced gamma emission (PIGE), a nuclear reaction based analytical technique, has been employed for measuring boron in soil samples. The concentrations of boron in soil samples collected from different parts of Bangladesh have been determined by measuring the gamma ray yield from the PIGE reactions. Forty samples have been analysed and boron has been found in 25 samples with concentrations lying between the range of 19.9-153 mg/kg, having a mean of 52.73 mg/kg. The PIGE sensitivity of boron in soil sample has been found to be 5 mg/kg for 100 μC irradiation. Some of the soil samples that have been analysed using the PIGE methodology have also been analysed for comparison by NRA facilities at the Institute of Geological and Nuclear Sciences Ltd., Lower Hutt, New Zealand. The results of the two measurements agree within ±16%, which indicates that the PIGE technique is a reliable method for analysing boron in soil sample. The simplicity and minimal requirement for the sample preparation and the clear knowledge of interfering nuclear reactions make PIGE technique an attractive method for the analysis of boron in arable soil. (author)
[en] The Old Rifle Site is a former vanadium and uranium ore-processing facility located adjacent to the Colorado River and approximately 0.3 miles east of the city of Rifle, CO. The former processing facilities have been removed and the site uranium mill tailings are interned at a disposal cell north of the city of Rifle. However, some low level remnant uranium contamination still exists at the Old Rifle site. In 2002, the United States Nuclear Regulatory Commission (US NRC) concurred with United States Department of Energy (US DOE) on a groundwater compliance strategy of natural flushing with institutional controls to decrease contaminant concentrations in the aquifer. In addition to active monitoring of contaminant concentrations, the site is also used for DOE Legacy Management (LM) and other DOE-funded small-scale field tests of remediation technologies. The purpose of this laboratory scale study was to evaluate the effectiveness of a hydroxyapatite (Ca10(PO4)6(OH)2) permeable reactive barrier and source area treatment in Old Rifle sediments. Phosphate treatment impact was evaluated by comparing uranium leaching and surface phase changes in untreated to PO4-treated sediments. The impact of the amount of phosphate precipitation in the sediment on uranium mobility was evaluated with three different phosphate loadings. A range of flow velocity and uranium concentration conditions (i.e., uranium flux through the phosphate-treated sediment) was also evaluated to quantify the uranium uptake mass and rate by the phosphate precipitate.
[en] In this project we have researched and evaluated the separation possibility of uranium ore in Palua area. Although scale and expenses of the project are limited, we have carried out this project during a year and had some reliable results. Uranium ore in Palua area which has concentrate of 440 ppm was separated into two main ingredients containing uranium concentrate more than 550 ppm and less than 190 ppm. (author)
[en] The high affinity of forest soil fungi for alkali metals such as potassium, rubidium, caesium as well as radiocaesium is shown and discussed. Good positive correlation was found between K: Rb concentration ratios in soil and in fungi, when correlation between K: Cs concentration ratios was less pronounced. (LN)
[en] Basalin (5-Propyl-B-(2-chloroethyl) 2,6 dinitro-4-trifluoromethyl aniline) is a selective pre-emergence herbicide used for the control of common weeds in cultivated fields in India. The dehydrogenase activity in a red loamy. soil and in cowpea rhizosphere incorporated with various concentrations of Basalin viz., 0 ppm, 2 ppm, 5 ppm and 10 ppm, over a period of 8 weeks incubation was studied following the method of Klein et al. (1971). There was no significant effect of Basalin on the dehydrogenase activity at the recommended level of application, i.e. 2 ppm. However, there was reduction in dehydrogenase activity at the higher levels of Basalin. This decrease in dehydrogenase activity was found to be correlated with a decrease in bacterial actinomycete and fungal plate counts