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Loss-of-Cooling Accidents:
Published in Geoffrey F. Hewitt, John G. Collier, Introduction to Nuclear Power, 2018
Geoffrey F. Hewitt, John G. Collier
The very high levels of radioactivity in the containment building after the accident were mainly due to the presence of radioactive krypton and xenon. Apart from krypton-85 (which has a 10-year half-life), most of the radioactive isotopes of krypton and xenon are short-lived. With the exception of approximately 10,000 curies of krypton-85, which were vented from the containment about 1 year after the accident, all the radioactive gases escaped in the first few days after the accident, and this led to a measurable increase in activity above the normal background level in the area surrounding the plant. However, very little (only 16 curies) of the iodine released from the fuel escaped from the containment. Evacuation of the area immediately surrounding the site 2 days after the accident involved about 50,000 households. However, exposure of the public to radioactivity was very small indeed, and the consequences in terms of additional cancer deaths are calculated to be undetectable in the surrounding population. Using the estimated total collective dose of 33 man-Sv, it is calculated that there will be less than 1 additional cancer death due to the accident in a total of 325,000 such deaths in the surrounding population over the next 30 years.
Soil-Water Budget
Published in Daniel B. Stephens, Andrea J. Kron, Andrea Kron, Vadose Zone Hydrology, 2018
Daniel B. Stephens, Andrea J. Kron, Andrea Kron
Krypton-85, a radioactive noble gas with a half-life of 10.76 years, is produced in the atmosphere by the interaction of cosmic rays with krypton-84. By far the greater source, however, is from nuclear weapons testing and reprocessing nuclear fuel rods (Ekwurzel et al., 1994). The atmospheric production of krypton-85 has increased steadily since about 1950. After precipitation infiltrates and no longer contacts the atmosphere, the krypton undergoes decay, but, owing to its inert characteristics, it does not interact chemically with the aquifer materials. Figure 6C illustrates the krypton activity in the northern atmosphere, and Figure 6D shows how to graphically determine the age of the water sample based on the sample collection date and the measured activity in groundwater.
The back-end of the nuclear fuel cycle: storing and transporting radioactive waste
Published in Peter R. Mounfield, World Nuclear Power, 2017
In managing the radioactive gaseous wastes the requirement is an effective means of capturing those that are particularly toxic or long lived so that they can go into long-term repositories, combined with controlled release of the others to the atmosphere in highly diluted form (Table 12.6). Capture is possible with carbon-14 but not yet with Tritium. Iodine-129 has a half-life of 16 million years and the best that can be done is to control the time, place and manner of dispersion into the biosphere (Figure 12.12). Krypton, which is a noble gas, is being released to the atmosphere in small amounts, but as reprocessing capacities grow the releases from individual plants might have to be restricted, not only to keep the radiation exposure down as far as reasonably retrievable in the local environment but also to avoid an increased accumulation of krypton-85 in the global atmosphere. Techniques to capture krypton are under development at Mol, Belgium, but the task is not easy and in 1988 they were only in the experimental stage.
Evaluation of filter media covered with spun fibres and containing thyme essential oil with antimicrobial properties
Published in Environmental Technology, 2022
Ana Isabela Pianowski Salussoglia, Clovis Wesley Oliveira de Souza, Eduardo Hiromitsu Tanabe, Mônica Lopes Aguiar
The nanoparticle collection efficiencies, permeabilities, and pressure drops of the filter media were measured using the filtration apparatus shown in Figure 2. The equipment consisted of an aerosol generator (Model 3079, TSI), a filtered air supply (Model 3074B, TSI), a diffusion dryer (Model 3062, TSI), a krypton-85 charge neutralizer (Model 3054, TSI), filter media apparatus, an americium-241 charge neutralizer, a flowmeter (Gilmont), and a scanning mobility particle sizer (SMPS) composed of an electrostatic classifier (Model 3080, TSI), a differential mobility analyzer, and a particle counter (Model 3776, TSI). The microparticle collection efficiency was measured using the filtration apparatus shown in Figure 3, consisting of a particle feeder (Model 3433, TSI), a diluter (Model 3302A, TSI), an aerodynamic particle sizer (APS) spectrometer (Model 3320, TSI), a flowmeter (Gilmont), and a pump.
Measuring aerosol size distributions with the aerodynamic aerosol classifier
Published in Aerosol Science and Technology, 2018
Tyler J. Johnson, Martin Irwin, Jonathan P. R. Symonds, Jason S. Olfert, Adam M. Boies
A TSI SMPS, consisting of Krypton-85 radioactive source, 3080 DMA (with 3081 long column), and 3775 CPC in series, measured the aerosol’s mobility size distribution. The SMPS was operated with an aerosol and sheath flow of 0.3 and 3 L/min, respectively, corresponding to a 14.6–661 nm mobility scan range or 13.4–629 nm aerodynamic scan range for a particle density of 914 kg/m3. Similar to the AAC-CPC system, the DMA setpoint was changed and the corresponding classified particle number concentration (N) was measured and recorded as a function of its mobility diameter setpoint. However, the DMA voltage was scanned exponentially to reduce the overall measurement time to 3 min, compared to an AAC-CPC measurement time of 10–15 min. To avoid introducing disagreement between different CPCs, the same 3775 CPC was switched between downstream of the AAC and DMA. The AAC or DMA was also bypassed to allow the CPC to directly measure the total particle number concentration () of the polydispersed aerosol.
Performance of two shrouded probes for the collection of liquid aerosols in a wind tunnel optimized for high air speeds
Published in Aerosol Science and Technology, 2020
Andrew Fearing, Ahmad Kalbasi-Ashtari, Alexander Zuniga, Hyoungmook Pak, John Haglund, Ho Young Kim, Maria King
Uranine (Fluorescein disodium salt C20H10Na2O5, TCI Inc. New Brunswick, NJ 08901-3605) and oleic acid (Octadecenoic acid, C18H34O2, Spectrum Chemical Manufacturing Corp., Gardena, CA, USA) at a mass (uranine) to volume (oleic acid) ratio of 8.93 were used for making the solutions for 10 µm liquid particles (Faulkner, Smith, and Haglund 2014). An HPLC pump (High Performance Liquid Chromatography, Series 1500, ChromTech, Inc., Apple Valley, MN, USA) was used to transfer the uranine solution to the nozzle of a vibrating orifice aerosol generator (VOAG; model 3450, TSI, Inc., Shoreview, MN, USA) at a constant flow rate (0.225 mL/min). The supplied pressurized air was passed through an air de-humidifier (Model 3Z528, Dayton Electric Mfg. Co., Chicago, IL, USA) and an air dryer to remove moisture. The compressed dry air was mixed with the fine and attached droplets of uranine to separate and disperse the generated liquid particles. The streamline from the nozzle of VOAG was directed to a Krypton-85 Aerosol Neutralizer (Model 54-0024, TSI Inc.) to reduce electrostatic charges between aerosols. The generated aerosols, prior to introduction into the wind tunnel, were analyzed by the aerodynamic particle sizer (APS, Model 3321, TSI, Inc.) to verify the sizes of generated particles. The dried air dispersion and air dilution of the VOAG system was adjusted to generate mainly monodispersed particles. Monodispersed uranine aerosol with an average particle diameter of 10 µm ± 1.16 GSD (geometric standard deviation) was generated in the VOAG and analyzed by the APS system.