Concrete Pad Research Articles

Vertodrom covering calculation and designing technology

The article is devoted to the analysis of existing methods of calculation of rigid heliport coverings, both domestic and foreign. Considerable attention is paid to the geometric dimensions in the plan and layout; location and orientation of heliports. Types of helipads are considered; materials used in the construction of heliports; type of structures (panels), designed for the construction of helicopter pads at the surface level (on any dense surface or ordinary soil), that successfully replace concrete, as well as for the reconstruction of worn and damaged concrete helicopter pads on rooftops and other heliport modifications; possible locations of helicopter pads, which may be different in size and configuration: mobile, off-road, ground, on the roofs of buildings and structures, on pontoons, on sea or river vessels and yachts, on offshore drilling platforms, by individual projects. Approaches to the improvement of the existing method of calculation and design of rigid helipads are analyzed.A comparative analysis of ICAO, FAA, SNiP 2.05.08-85 regulatory documentation and recommendations, which do not provide a clear idea of ​​the method of calculating the thickness of rigid heliports, do not separate the calculation of heliports from the calculation of aerodrome pavements, do not consider any critical cross sections in calculating the load from helicopters and the main differences in designing coverings for helicopters from those for aircraft maintenance, connected with the dynamics of the takeoff and landing operations.As the weight of modern helicopters varies widely, it has been established that different types of coverings must be used for different weight categories (from structures raised above the ground level for light and medium-weight helicopters to cement concrete coverings for heavy helicopters).

The suitability of smartphone camera sensors for detecting radiation

The advanced image sensors installed on now-ubiquitous smartphones can be used to detect ionising radiation in addition to visible light. Radiation incidents on a smartphone camera’s Complementary Metal Oxide Semiconductor (CMOS) sensor creates a signal which can be isolated from a visible light signal to turn the smartphone into a radiation detector. This work aims to report a detailed investigation of a well-reviewed smartphone application for radiation dosimetry that is available for popular smartphone devices under a calibration protocol that is typically used for the commercial calibration of radiation detectors. The iPhone 6s smartphone, which has a CMOS camera sensor, was used in this study. Black tape was utilized to block visible light. The Radioactivity counter app developed by Rolf-Dieter Klein and available on Apple’s App Store was installed on the device and tested using a calibrated radioactive source, calibration concrete pads with a range of known concentrations of radioactive elements, and in direct sunlight. The smartphone CMOS sensor is sensitive to radiation doses as low as 10 µGy/h, with a linear dose response and an angular dependence. The RadioactivityCounter app is limited in that it requires 4–10 min to offer a stable measurement. The precision of the measurement is also affected by heat and a smartphone’s battery level. Although the smartphone is not as accurate as a conventional detector, it is useful enough to detect radiation before the radiation reaches hazardous levels. It can also be used for personal dose assessments and as an alarm for the presence of high radiation levels.

Effects of bale feeder design on hay waste, intake, and apparent diet digestibility in gestating beef cows.

Two experiments were conducted to determine the effects of feeder design on hay intake, apparent diet digestibility, and hay waste in gestating beef cows. Native tallgrass prairie hay and a protein supplement was fed throughout both experiments. In Exp. 1, 56 crossbred cows were used in a Latin square arrangement. Feeder design treatments included a conventional open bottom steel ring (OBSR), an open bottom polyethylene pipe ring (POLY); a sheeted bottom steel ring (RING), and a sheeted bottom steel ring with a basket (BASK). Cows were weighed and allotted based on BW to one of four previously grazed 2.0 ha paddocks equipped with a concrete feeding pad. Fourteen cows were assigned to each paddock and three round bales were fed consecutively within each treatment period. The cows acclimated to the feeders while the first bale was being consumed. Subsequently, hay waste data were collected while the second and third bale within each period were being consumed. Waste was measured for each bale at 24, 48, 72, and 96 h after each bale was introduced into the pen. Hay waste was significantly affected by hay feeder design with 19.7, 21.1, 12.4, and 5.5% of original bale weight wasted for OBSR, POLY, RING, and BASK, respectively (P < 0.01). There was a feeder design × day interaction (P < 0.01) with greater waste when the bale was first introduced into the pen in OBSR, POLY, and RING feeders and gradually declining thereafter, while waste from the BASK feeder was consistently low. There was a tendency (P = 0.06) for cows eating from OBSR feeders to consume less hay than cows eating from RING feeders. Feeder design did not influence apparent diet digestibility (P = 0.46). In Exp. 2, 64 crossbred cows (body weight = 590 ± 59 kg) were used to determine waste, forage intake, and apparent diet digestibility when hay was fed from a sheeted bottom steel ring (RING) or a RING feeder with a cone insert (CONE). More hay was wasted when cows were fed from RING feeders compared to CONE feeders (11.9% vs. 4.8%, P < 0.01). Feeder design had no effect on DMI or apparent digestibility (P > 0.45). Hay savings from adopting a more conservative feeder design can have a dramatic influence on hay utilization by beef cows and thus on cost of production.

88 Exploring equine mortality composting

Composting is an environmentally friendly, economical, and bio secure method for livestock mortality disposal. Recent changes in availability of rendering for chemically-euthanized animals has created a need to explore composting. The objectives of this study were to demonstrate successful equine mortality composting in the winter and document sodium pentobarbital concentrations throughout the process. The authors hypothesized composting would degrade carcasses and reduce pentobarbital concentrations. On 26 September 2019, 4 horses (451 ± 36 kg) were euthanized for terminal medical reasons by intravenous administration of sodium pentobarbital (88 ± 2 mg/kg; Fatal-Plus, Vortech Pharmaceuticals, LTD, Dearborn, MI). Carcasses were transported immediately to a private composting site. Four separate compost piles were constructed on a 6.1- by 27.4-m concrete pad. Each pile consisted of 46 cm of playground woodchips, 8 cm of dry pine shavings, a horse carcass, and 61 cm of a 2:1 mixture of horse stall waste and cattle feedlot waste. Data loggers were placed at 46- and 91-cm depths to record pile temperatures every 8 h. Compost piles were topped with manure mixture at d 9 to cover cracks, turned at d 50 when pile temperatures were ≤54.4°C, and concluded on d 216 following approximately 5 mo. of curing (≤43.3°C). On d 50 and 216 piles were cut into 3 mirrored cross sections and subsampled (n = 36) to form one composite sample per cross section. Samples were analyzed for sodium pentobarbital (on an “as is” basis) and nutrient content. Carcass degradation was scored on a subjective scale (1 = discernable carcass, 5 = few large brittle bones). Pentobarbital concentrations were compared using a 2-way ANOVA with cross section and day as fixed effects. P-values < 0.05 were considered significant. Three piles received a carcass degradation score of 2 at d 50 with soft tissue, hair, and hide present. By d 216, all piles received scores of 3 (n = 2) or 4 (n = 2) with some hide and large bones remaining. Pentobarbital concentrations declined between d 50 and d 216; however, remained detectable at d 216. On average, pentobarbital concentrations tended to be higher (9.05 mg/kg) at the center of the compost pile on d 50 (P < 0.05); however, on d 216 concentrations were similar (0.432 to 0.735 mg/kg; P > 0.05) among cross sections. While pentobarbital concentrations at d 216 were minimal, further research is needed to determine environmental implications of composting chemically-euthanized equines. These findings suggest mortality composting is an effective method for disposing of equine carcasses.

Experimental study on cyclic behavior of post-tensioned segmental retaining walls (PSRWs)

This paper reports on an experimental study on nine Post-tensioned Segmental Retaining Walls (PSRWs). All the walls were post-tensioned and tested under incrementally increasing cyclic loading. Each test wall was constructed using four T-shaped precast concrete blocks, assembled on top of each other with dry joints. The integrity of the system was maintained using post-tensioning (PT). Different levels of PT forces were applied to investigate the effect of it. Different wall-footing interface materials were used including steel plate, concrete and neoprene pad. Conventional concrete and crumb rubberized concrete was used to investigate the effect of concrete properties on the structural behavior of retaining walls. Three walls with confinement (confined with either Carbon Fiber Reinforced Polymer (CFRP), steel reinforcement or steel face plate) were tested. The force–displacement responses, energy dissipation, post-tensioning stresses, gap rotation, lateral stiffness, and normal strains were observed and compared. The results from this study showed that the level of axial stress ratio, eccentricity of pre-stressing as well as the properties of the wall-footing interface material is critical to provide enough lateral strength and stiffness for engineering design of the PSRW. The wall with steel plate on compression face had the largest ultimate strength. The specimen having largest PT force generated largest initial and secant stiffness. Additional reinforcement of the bottom most segment is also required to avoid sudden failure and increase ductility in T-shaped blocks. Lateral stiffness increases in conventional concrete was much higher than rubberized concrete when PT force was increased. None of concrete confinement methods applied (CFRP confinement, steel reinforcement and steel face plate) affected energy dissipation characteristics of the tested walls. Using neoprene as the interface material for wall-footing significantly increased energy dissipation and concrete wall-footing interface showed more energy dissipation in comparison to steel interface material. Stiffness degradation of all walls had similar rate against wall lateral displacement. This paper concluded that the proposed segmental retaining wall system is potentially a practical alternative to accelerate the construction of retaining walls using precast concrete blocks.

Axial compressive capacity of RC square columns strengthened by prestressed CFRP with RPC pads

In this paper, a new technique to strengthen RC square columns using prestressed CFRP patched by ractive powder concrete (RPC) pad is developed. Fifteen RC square columns strengthened using this new technique were tested under axial compression loads. The influence of the level of prestress force, the number of wrapping layers and the strengthening process on the strengthening effect of this new technique was investigated. The improvement of axial compressive capacities and failure modes of the columns were studied. The results show that: this new technique provides better strengthening to the concrete columns with a fast strengthening process. The axial compression capacity of RC columns increases up to 80%. It is also found that, increasing the prestress can also improve the performance of the columns under normal working condition. A formula to predict the axial compression capacity of the columns is developed in this paper, which can accurately predict the axial compressive strength of the concrete columns strengthened by this new technique.

Three-dimensional analysis of anchored wall with concrete bearing pads

PurposeAnchorage with concrete bearing pad is commonly used in Iran for stabilization of excavations because of the ease of construction, less costs and less time consumption than the soldier pile method. In this method, a wall facing which includes the concrete bearing pads at the location of the anchors and a shotcrete layer between the bearing pads is constructed parallel to the excavation operation similar to the nailing method.Design/methodology/approachIn this paper, using the finite element software Abaqus, a three-dimensional model of the above-mentioned type of wall is constructed, and the effect of spacing and size of bearing pads on the wall behavior is discussed.FindingsAccording to the obtained results, the size of the concrete bearing pads has little effect on wall deformations, but the internal forces and bending moments developed in the shotcrete layer between the bearing pads are greatly influenced by the bearing pads dimensions and spacing.Originality/valueOwing to the discrete elements of the wall facing, the behavior of this system is completely three-dimensional.

Comparative Study of Anchored Wall Performance with Two Facing Designs

The present study compared the performance of soldier pile and concrete bearing pad anchored wall facings. Using Abaqus finite element software, two case studies have been precisely represented for the facing designs and effects of the parameters of soil type, spacing of anchors and facings, surcharge and facing sizes were investigated. The analysis results indicate that the soldier pile method can efficiently reduce anchored wall deformation, especially at the wall crest. The horizontal deformation at the top of the anchored soldier pile wall was about half of the wall anchored with concrete bearing pads. Soil arching between the anchors in the horizontal direction was more effective in the soldier pile wall and the bending moment of the laggings in the soldier pile wall was considerably less than that of the anchorage with bearing pads.

Assessing Seasonal Changes in Microgravity at Yellowstone Caldera

AbstractMicrogravity time series at active volcanoes can provide an indication of mass change related to subsurface magmatic processes, but uncertainty is often introduced by hydrologic variations and other noise sources that cannot easily be isolated. We empirically assessed seasonality and noise by conducting four surveys over the course of May–October 2017 at Yellowstone caldera, Wyoming. Yellowstone experiences frequent changes in the rates and styles of seismicity and surface deformation, but the mechanisms of these changes are poorly understood. Past gravity data from the caldera have yielded ambiguous results, possibly due to hydrologic noise. Given the strong visually observable changes in surface water and snow conditions over the course of our surveys, we expected to see significant variations in gravity. The net change in gravity, however, was less than 20 μGal at most sites, and there was no strong correlation with river and lake levels or snow conditions. Seasonal changes in gravity are therefore small compared to those that would be expected from magmatic activity, although they may be on the same order as those associated with Yellowstone's hydrothermal system. We did find that noise levels in gravity data were highly dependent on site characteristics, with bedrock sites away from trees yielding the lowest levels of noise, and thin concrete pads in forested areas the highest. These results can be used to plan future surveys at Yellowstone and to reinterpret past data, and they provide guidance in terms of best practices for repeat gravity work on volcanoes worldwide.

Transient large-scale chlorine releases in the Jack Rabbit II field tests: Rainout source data analysis from video records

Sponsored by the U.S. Department of Homeland Security Science & Technology (DHS S&T) Chemical Security Analysis Center (CSAC), the U.S. Department of Defense (DoD) Defense Threat Reduction Agency (DTRA), Transport Canada, and Defence Research and Development Canada (DRDC), the Jack Rabbit II tests were designed to release liquid chlorine at ambient temperature in quantities of 5–20 T for the purpose of quantifying the behavior and hazards of catastrophic chlorine releases at scales represented by rail and truck transport vessels. In 2015, five successful field trials were conducted in which chlorine was released in quantities of 5–10 tons through a 6-inch circular breach in the tank and directed vertically downward at 1 m elevation over a concrete pad. In 2016, three additional trials were conducted with releases of 10 tons also through 6-inch circular breaches at different release orientations. A final 20 ton test was conducted in 2016. Data from the test program is available. This paper summarizes an analysis of the available data from the concrete pad including analysis of the temperature measurements above and below grade in the concrete pad. Assessment of the chlorine rainout is estimated based on temperature measurements and available video data analysis.

Construction and Characterization of Transportable Calibration Pads for Calibration of Portable and Airborne Gamma Ray Spectrometers in India

Ground and airborne gamma ray spectrometers are routinely used in uranium exploration for search of deposits and lithological mapping. These systems are calibrated using standard concrete calibration pads which are constructed with known concentrations of K, U and Th and simulate the infinite source geometry for gamma ray survey instruments. In India Atomic Minerals Directorate for Exploration and Research, a constituent of Department of Atomic Energy created such calibration facility at Nagpur civil Airport in 1984 and maintained it till date. The cost of maintaining these old pads is very high, therefore we have constructed new transportable calibration pads which are much smaller in size (1m x 1m x 30cm) and also transportable to field areas. Five pads namely Background pad, potassium pad, uranium pad, thorium pad and composite pad have been constructed. These are made of concrete spiked with pre determined concentrations of radio-elements uranium, thorium and potassium. These transportable calibration pads are 750kg in weight and are mounted on a trolley. This has eliminated the need for large standard calibration pads, which needed an airport with very high land leasing costs and thereby reducing the maintenance cost significantly. A very distinctive feature of designed transportable pads as compared to pads worldwide, is the achievement of high density and high compressive strength. This high density has resulted in higher sensitivity thereby improving the statistical accuracy of calibration. This has also resulted in reducing the fluctuations in calibration due to moisture in field condition. Another distinctive feature is the achievement of higher potassium concentration > 8.0% in potassium pad. Creation of this new calibration facility has resulted in substantial savings to government exchequer by eliminating the need of the airport. This has enabled calibration in the field areas with easy transportability and thereby reducing the downtime of the survey operations in uranium exploration. This paper describes the design and fabrication of transportable calibration pads in India.

Feasibility Analysis of Surface Rail in The Revitalization of The Railway Road

The railway lines are an integral construction made of steel, concrete or other construction are located on the surface, below and above ground or dangling along with devices that direct the course of the train. Reflecting on the success of the revitalization of the railway line Padang-Pariaman, PT. Railway DIVRE II West Sumatra recently returned to the revitalization of the railway line Lubuk Alung–Kayu Tanam. In this final project feasibility analysis back to the road construction railroad Lubuk Alung-Kayu Tanam considering this path has not been used and an increase in the construction of the railroad on the route. The methodology used is the collection of data from related parties subsequently perform the calculation and analysis of railroad construction that has been revitalized. Data obtained from the calculation of the voltage rails on existing condition of 1380.34 kg/cm2 and the voltage rails after revitalized by 840.601 kg/cm2 while rail voltage maximum allowed is 1325 kg/cm2, the rail existing deserves to be revitalized. Iron bearing on the condition of the existing able to withstand a load of 6761.69 kg, while the load caused by railbus is 8568.986 kg so that the iron bearing existing not worth traversed railbus axle 18 ton and made improvement to the concrete pads. After upgrading, held their concrete pads capable of 23241.678 kg load and expenses incurred as a result of railbus axle 18 tons of concrete pads amounted to 6986.276. Concrete pads so deserve to be passed railbus axle 18 tons. The results of this thesis states that the construction of a rail road Lubuk Alung-Kayu Tanam deserves to be revitalized because of the condition of the existing construction rails and bearings are not able to withstand the stresses and loads that occur due railbus 18 tons passing through.

Distribution of phthalate esters in underground water from power transmission sites in Warri Metropolis, Delta State, Nigeria

This study investigates the distribution of phthalateacid esters (PAEs) in groundwater from some power stations in Delta State. Groundwater samples were collected from eight power transmission and distribution stations. Concentrations (μg/L) of six phthalate acid esters compounds in the groundwater ranged from 0.000–2.547(DMP), 0.053–0.180(DEP), 0.100–0.443 (DBP), 0.400-0.660(DEHP) and 0.000-0.020 (DnOP), while BBP was not detected in all the locations. Lowest total PAEs concentration was recorded in Edjeba Station (0.994±0.040μg/L) while the highest concentration was recorded in Mofo Station (3.380±0.012μg/L). Analysis of variance showed significant difference in concentration of DMP (p<0.5) from the eight transmission stations. DMP, DEP and DBP concentration in groundwater were found to be at level that does not pose immediate threat. Despite this, it would be advisable to continue to monitor the presence of these substances in water. DEHP content was high in most samples from the different stations and this is of serious concern, because it has been proven to be carcinogenic. It is advised that most of the old dilapidated transformers and other electrical equipment containing organic contaminant such polychlorobiphenyl (PCB) which is a major contributor of phthalate acids into water bodiesbe replaced with new ones and concrete bundwall built round the transformers to prevent unwholesome seepages into the environment. There should also be appropriate storage, decontamination and disposal of contaminated units prior to final disposal. Decommissioned transformers and equipment containing PCB should be stored on a concrete pad with curbs sufficient to contain the liquid contents. Keywords: Transmission stations, Phthalates acid esters, Underground water, GC-MS analysis

Near-field array measurements of F-35 aircraft noise

Noise source measurement and modeling efforts are being conducted for current and future generations of high-performance military aircraft. A near-field microphone array was used in a noise measurement of F-35A and F-35B aircraft at Edwards Air Force Base in 2013 in order to extract source models. The two aircraft measured were tethered to the ground on a concrete run-up pad. The array consisted of 76 sensors, spanned 32 m, and was placed on the ground approximately 7 m from the jet plume. The engines operated over a full range of power settings from idle through full afterburner. In preparation for the execution of source modeling efforts, these near-field data are explored and compared to far-field data published previously [James et al., AIAA Paper 2015-2375]. [Work supported by USAFRL through F-35 JPO.]

Санитарно-паразитологическая и экономическая оценка методов обеззараживания стоков и навоза на свинокомплексах

Objective of research: the sanitary-veterinary and economic evaluation of the disinfecting effect of different technologies applied for decontamination of livestock manure and sewage from invasive pathogens of pigs as well as for conversion of these wastes. Materials and methods: The degree of contamination of liquid manure from pig farms with eggs and helminth larvae, cysts and oocysts of parasitic protozoa, was studied on the samples collected once a month at farms of the Moscow region, and once every two months at farms of the Republic of Mordovia. Sampling, transportation and investigation of samples were carried out by the method of A. Cherepanov (1972). Samples were taken in the morning at 3-5 points using IMOP sampler 1000. At the sampling point, an inventory was created where the date, location, selection point and its sample volume were indicated. To prevent the development of microflora in the samples, a certain amount of preserving agent was added. When sampling solid manure fraction from the surface, middle and lower level, manure mass was selected horizontally at each level from 3-5 points, thoroughly mixed, then the averaged sample (1.0 kg) was placed in a plastic bag. To confirm the viability of helminth eggs detected by coproovoscopic examinations, eggs were transferred with a micropipette into Petri dishes and cultured in an thermostat at a temperature 26˚C in a humid environment, periodically aerating and observing the development of the embryo. Comparative assessment of the effectiveness of the treatment facilities in selected pig farms was performed by comparing the number of invasive elements in 1 liter of liquid manure entering and flowing out of the treatment facilities. Results and discussion: at all three selected pig farms, the most intense infections with helminth eggs, cysts and oocysts parasitic protozoa were found in raw sewage, what indicates a lack of effectiveness of anti-parasitic measures at the farm. JSC “Mordovia bacon” with 54 thousand pig heads a year is the only one of three inspected farms, where liquid manure is separated into fractions, followed by disinfestation of solid fraction on concrete pads with further application of manure as an organic fertilizer. Due to mechanical separation of liquid manure into fractions applied at this farm, the number of parasitic elements of internal parasites of pigs (eggs of Ascaris, trihotsefal, esophagitis, coccidia oocysts and cysts balantidiums) in 1 kg solid fraction was 586 ind. The efficiency of decontamination of liquid manure from parasitic elements, taking into account this treatment method was 53,6-73,4%. Biothermal decontamination of solid fraction of manure piles is achieved within 3-5 months (100%), depending on the season and used in fields as organic fertilizer.

Comparison between simulation and experimental result of the scale down vertical concrete cask under the historical earthquake hit

In recent years, the final disposal facility for the long-term storage of high radioactive waste is an important issue and an urgent task for nuclear Industry. This study is focus on the understanding the procedure of dry storage system in a nuclear power plant. The dry storage system is known as transportable storage canister (TSC) packing by using spent fuel placed in vertical concrete cask (VCC) or VCC with add-on-shell (AOS) canister and then those conveyed VCC or AOS will be put on the concrete pad. A numerical simulation for evaluation the behavior of VCC and AOC under the earthquake hits is used the finite element model by LS-DYNA and the real seismic behavior is obtained using shaking table test. Test results indicate that the simulation by numerical model can slightly simulate the dynamic records by shaking table test. This is because that the behavior of shaking table test is the rocking motion but the numerical model is the sliding motion. The surface roughness between the cask and concrete pad is an important variable and it needs more numerical simulation to solve the interface and friction coefficient between the cask and concrete pad.

Thermomechanical behaviour of airfield concrete pads supporting joint strike fighter F-35B

The Lockheed Martin F-35B Lightning II is the Short Take-Off/Vertical Landing (STOVL) aircraft variant of the joint strike fighter. The new dual-cycle propulsion system, which permits the STOVL operations, exposes the airfield pavements to extremely critical thermal conditions (temperatures exceeding 930°C and heating rate of about 85°C s−1). This study permitted to analyse the thermomechanical behaviour of an ordinary concrete pad during the F-35B aircraft vertical landing. The numerical analysis provided a detailed picture of the pavement stress state generated by the jet gases, opening the scenario to different planning solutions. The results highlighted how the damage, in the form of thermomechanical spalling, occurred in the top 2–5 mm of the pavement surface. One of the possible design solutions for high-performance vertical landing pads, supporting the F-35B aircraft, could be a two-layered pavement characterised by a thin (2.5 cm) fibre-reinforced Very High-Strength Concrete overlay.

Establishing a NORM based radiation calibration facility

An environmental radiation calibration facility has been constructed by the Radiation and Nuclear Sciences unit of Queensland Health at the Forensic and Scientific Services Coopers Plains campus in Brisbane. This facility consists of five low density concrete pads, spiked with a NORM source, to simulate soil and effectively provide a number of semi-infinite uniformly distributed sources for improved energy response calibrations of radiation equipment used in NORM measurements. The pads have been sealed with an environmental epoxy compound to restrict radon loss and so enhance the quality of secular equilibrium achieved. Monte Carlo models (MCNP),used to establish suitable design parameters and identify appropriate geometric correction factors linking the air kerma measured above these calibration pads to that predicted for an infinite plane using adjusted ICRU53 data, are discussed. Use of these correction factors as well as adjustments for cosmic radiation and the impact of surrounding low levels of NORM in the soil, allows for good agreement between the radiation fields predicted and measured above the pads at both 0.15 m and 1 m.

Monitoring airborne gamma ray spectrometer sensitivities using the natural background

In many airborne gamma-ray surveys, uranium and thorium sources are required to verify that the airborne system maintains the same sensitivity for each survey flight. Recently, due to radioactive material regulations, it has become increasingly difficult to transport these radioactive sources around the world. Measurements of the natural radioactivity of the ground, recorded as part of source tests carried out in Tanzania were analysed. These data involved three different aircraft at two bases of operation. The results have shown that in all cases the potassium and thorium background measurements were more consistent than the measurements from the uranium and thorium sources. In addition, the variations in the potassium and thorium measurements could be reduced even further by removing the effect of airborne radon daughter fluctuations using stripping ratios derived from measurements on concrete calibration pads.

Safety Assessment of a Metal Cask under Aircraft Engine Crash

Abstract The structural integrity of a dual-purpose metal cask currently under development by the Korea Radioactive Waste Agency (KORAD) was evaluated, through numerical simulations and a model test, under high-speed missile impact reflecting targeted aircraft crash conditions. The impact conditions were carefully chosen through a survey on accident cases and recommendations from literature. In the impact scenario, a missile flying horizontally hits the top side of the cask, which is freestanding on a concrete pad, with a velocity of 150 m/s. A simplified missile simulating a commercial aircraft engine was designed from an impact load–time function available in literature. In the analyses, the dynamic behavior of the metal cask and the integrity of the containment boundary were assessed. The simulation results were compared with the test results for a 1:3 scale model. Although the dynamic behavior of the cask in the model test did not match exactly with the prediction from the numerical simulation, other structural responses, such as the acceleration and strain history during the impact, showed very good agreement. Moreover, the containment function of the cask survived the missile impact as expected from the numerical simulation. Thus, the procedure and methodology adopted in the structural numerical analyses were successfully validated.