Atmospheric Nuclear Detonation Research Articles

Effects of a nuclear-disturbed environment on electromagnetic wave propagation through the atmosphere.

This paper investigates the effects of a nuclear-disturbed environment on the transmission of electromagnetic (EM) waves through the atmosphere. An atmospheric nuclear detonation can produce heightened free electron densities in the surrounding atmosphere that can disrupt EM waves that propagate through the disturbed region. Radiation transport models simulated the ionization and free electron densities created in the atmosphere from a 1 MT detonation at heights of burst of 5 km, 25 km, and 75 km. Recombination rates for the free electrons in the atmosphere were applied, from previous work in the literature, to determine the nuclear-induced electron densities as a function of time and space after the detonation. A ray-tracing algorithm was applied to determine the refraction and reflection of waves propagating in the different nuclear-disturbed environments. The simulation results show that the free electron plasma created from an atmospheric nuclear detonation depend on the height of burst of the weapon, the weapon yield, and the time after detonation. Detonations at higher altitudes produce higher free electron densities for greater durations and over larger ranges. The larger the free electron densities, the greater the impact on EM wavelengths in regards to refraction, reflection, and absorption in the atmosphere. An analysis of modern infrastructure and the effects of nuclear-disturbed atmospheres on different signal wavelengths and systems is discussed.

Feature detection and matching on atmospheric nuclear detonation video

Automated feature matching of nuclear detonations (NUDETs) enables three-dimensional point cloud reconstruction, and establishment a volume-based model to reduce uncertainty in estimating the yield of NUDETs solely from video. Establishing a volume-based model requires feature correspondences between wide viewpoints of 58°–110° that are larger than scale-invariant feature transform-based techniques can reliably match. The presented technique detects relative bright features in the NUDET known as ‘hotspots,’ and matches them across wide viewpoints using a spherical based object model. Results show that hotspots can be detected with a 71.95% hit rate and 86.03% precision. Hotspots are matched to films from different viewpoints with 76.6% correctness and a standard deviation of 16.4%. Hotspot descriptors are also matched in time sequence with 99.6% correctness and a standard deviation of 1.07%. The results demonstrate that a spherical model can serve as a viable descriptor model for matching across wide viewpoints when the object is known to be spherical. It also demonstrates an automated feature detection and matching combination that enables features to be matched from unsynchronised video across wide viewpoints of 58°–110° on spherical objects where state-of-the-art techniques are insufficient.

Long-range tropospheric transport of uranium and plutonium weapons fallout from Semipalatinsk nuclear test site to Norway

A combination of state-of-the-art isotopic fingerprinting techniques and atmospheric transport modelling using real-time historical meteorological data has been used to demonstrate direct tropospheric transport of radioactive debris from specific nuclear detonations at the Semipalatinsk test site in Kazakhstan to Norway via large areas of Europe. A selection of archived air filters collected at ground level at 9 stations in Norway during the most intensive atmospheric nuclear weapon testing periods (1957–1958 and 1961–1962) has been screened for radioactive particles and analysed with respect to the concentrations and atom ratios of plutonium (Pu) and uranium (U) using accelerator mass spectrometry (AMS). Digital autoradiography screening demonstrated the presence of radioactive particles in the filters. Concentrations of 236U (0.17–23nBqm−3) and 239+240Pu (1.3–782μBqm−3) as well as the atom ratios 240Pu/239Pu (0.0517–0.237) and 236U/239Pu (0.0188–0.7) varied widely indicating several different sources. Filter samples from autumn and winter tended to have lower atom ratios than those sampled in spring and summer, and this likely reflects a tropospheric influence in months with little stratospheric fallout. Very high 236U, 239+240Pu and gross beta activity concentrations as well as low 240Pu/239Pu (0.0517–0.077), 241Pu/239Pu (0.00025–0.00062) and 236U/239Pu (0.0188–0.046) atom ratios, characteristic of close-in and tropospheric fallout, were observed in filters collected at all stations in Nov 1962, 7–12days after three low-yield detonations at Semipalatinsk (Kazakhstan). Atmospheric transport modelling (NOAA HYSPLIT_4) using real-time meteorological data confirmed that long range transport of radionuclides, and possibly radioactive particles, from Semipalatinsk to Norway during this period was plausible. The present work shows that direct tropospheric transport of fallout from atmospheric nuclear detonations periodically may have had much larger influence on radionuclide air concentrations and deposition than previously anticipated.

Chronology of Pu isotopes and 236U in an Arctic ice core

In the present work, state of the art isotopic fingerprinting techniques are applied to an Arctic ice core in order to quantify deposition of U and Pu, and to identify possible tropospheric transport of debris from former Soviet Union test sites Semipalatinsk (Central Asia) and Novaya Zemlya (Arctic Ocean). An ice core chronology of 236U, 239Pu, and 240Pu concentrations, and atom ratios, measured by accelerator mass spectrometry in a 28.6m deep ice core from the Austfonna glacier at Nordaustlandet, Svalbard is presented. The ice core chronology corresponds to the period 1949 to 1999. The main sources of Pu and 236U contamination in the Arctic were the atmospheric nuclear detonations in the period 1945 to 1980, as global fallout, and tropospheric fallout from the former Soviet Union test sites Novaya Zemlya and Semipalatinsk. Activity concentrations of 239+240Pu ranged from 0.008 to 0.254mBqcm−2 and 236U from 0.0039 to 0.053μBqcm−2. Concentrations varied in concordance with 137Cs concentrations in the same ice core. In contrast to previous published results, the concentrations of Pu and 236U were found to be higher at depths corresponding to the pre-moratorium period (1949 to 1959) than to the post-moratorium period (1961 and 1962). The 240Pu/239Pu ratio ranged from 0.15 to 0.19, and 236U/239Pu ranged from 0.18 to 1.4. The Pu atom ratios ranged within the limits of global fallout in the most intensive period of nuclear atmospheric testing (1952 to 1962). To the best knowledge of the authors the present work is the first publication on biogeochemical cycles with respect to 236U concentrations and 236U/239Pu atom ratios in the Arctic and in ice cores.

Characterizing noise in the global nuclear weapon monitoring system

Under the auspices of the Comprehensive Nuclear‐Test‐Ban Treaty Organization, a worldwide monitoring system designed to detect the illegal testing of nuclear weaponry has been under construction since 1999. The International Monitoring System is composed of a range of sensors, including detectors for hydroacoustic and seismic signals, and when completed, will include 60 infrasound measurement arrays set to detect low‐frequency sound waves produced by an atmospheric nuclear detonation.

Evaluation of Food Contamination and Health Risks Caused by Radioactive Fallout 137Cs Released from Atmospheric Nuclear Detonation Tests

Evaluation of Food Contamination and Health Risks Caused by Radioactive Fallout <SUP>137</SUP>Cs Released from Atmospheric Nuclear Detonation Tests

Numerical simulation of the ionization effects of low-and high-altitude nuclear explosions

Low-altitude and high-altitude nuclear explosions are sources of intensive additional ionization in ionosphere. In this paper, in terms of the ionization equilibrium equation system and the equation of energy deposition of radiation in atmosphere, and considering the influence of atmosphere, the temporal and spacial distribution of ionization effects caused by atmospheric nuclear detonation are investigated. The calculated results show that the maximum of additional free electron density produced by low-altitude nuclear explosion is greater than that by the high-altitude nuclear burst. As to the influence of instant nuclear radiation, there is obvious difference between the low-altitude and the high-altitude explosions. The influence range and the continuance time caused by delayed nuclear radiation is less for the low-altitude nuclear detonation than that for the high-altitude one.

Developing a Finite Difference Time Domain Parallel Code for Nuclear Electromagnetic Field Simulation

A two dimensional finite-difference time-domain code has been developed for complete simulation of nuclear electromagnetic pulse (NEMP) originating from an atmospheric nuclear detonation. The modules of NEMP simulation code describing various physics aspects are discussed. Typical results of the serial code for Compton current estimated from detailed neutron-gamma transport, induced air conductivity and electromagnetic fields are presented. The need for parallelizing such code has been explained. The parallel implementation using domain decomposition technique of message passing interface paradigm is described. The efficiency of the parallel code has been studied with increasing number of processors. The limitations of speed-up due to communication times are discussed.

New Bomb Pulse Radiocarbon Records from Annual Tree Rings in the Northern Hemisphere Temperate Region

The “bomb” radiocarbon spike induced by atmospheric nuclear detonations has been reconstructed at a latitude of 40°N by measuring the 14C content in annual rings of a living pine (Pinus pinea) at the Accelerator Mass Spectrometry facility of the University of Lecce. We report how the samples were taken, selected, prepared for analysis, and measured. The results are in good agreement with other data sets available for the Northern Hemisphere temperate regions, showing that a curve for the calibration of 14C dates, valid for the whole Northern Hemisphere, can be established for the second half of the 20th century.

Flow, stock and destination of radioactive fallout Cs-137 in the global environment

Environmental fate of radionuclide caesium-137 (Cs-137), which was released for more than 30 years since 1945 to the global environment by the atmospheric nuclear detonation tests, was analyzed from an aspect to determine the transport rate between environmental media, the accumulation and mass distribution in each media and the final destination. The mathematical model was developed and validated by comparing the model estimation with the monitoring data, and the final distribution of Cs-137 and its overall decreasing rate were evaluated together with the health risks to the reference Japanese. The mass distribution simulation showed that the final destination of the fallout Cs-137 is the deeper land and the ocean bottom, and that the apparent decreasing rate of Cs-137 in the humans' living environment is larger than the physical half-life of Cs-137 due to the environmental acceleration of radionuclide transportation.

Predicted net efflux of radiocarbon from the ocean and increase in atmospheric radiocarbon content

Prior to changes introduced by man, production of radiocarbon (14C) in the stratosphere nearly balanced the flux of 14C from the atmosphere to the ocean and land biosphere, which in turn nearly balanced radioactive decay in these 14C reservoirs. This balance has been altered by land‐use changes, fossil‐fuel burning, and atmospheric nuclear detonations. Here, we use a model of the global carbon cycle to quantify these radiocarbon fluxes and make predictions about their magnitude in the future. Atmospheric nuclear detonations increased atmospheric 14C content by about 80% by the mid‐1960's. Since that time, the 14C content of the atmosphere has been diminishing as this bomb radiocarbon has been entering the oceans and terrestrial biosphere. However, we predict that atmospheric 14C content will reach a minimum and start to increase within the next few years if fossil‐fuel burning continues according to a “business‐as‐usual” scenario, even though fossil fuels are devoid of 14C. This will happen because fossil‐fuel carbon diminishes the net flux of 14C from the atmosphere to the oceans and land biosphere, forcing 14C to accumulate in the atmosphere. Furthermore, the net flux of both bomb and natural 14C into the ocean are predicted to continue to slow and then, in the middle of the next century, to reverse, so that there will be a net flux of 14C from the ocean to the atmosphere. The predicted reversal of net 14C fluxes into the ocean is a further example of human impacts on the global carbon cycle.

A dosimetric determination of 137Cs ingestion from global fallout and the related risks to Japanese.

137Cs released from atmospheric nuclear detonation tests has been transported worldwide in the environment and finally taken up by humans through various pathways. In particular, ingestion pathways are important for evaluating the human health risks caused by the chronic global low-level radioactive contamination. In this research, the mathematical model for the evaluation of the dietary intake of 137Cs and the related risks to Japanese are proposed by coupling the previously published global 137Cs distribution model with the regional models such as various food ingestion models and the model of the domestic and international supply. Predictions from the proposed model were compared with the monitoring data of 137Cs in Japanese total diet as an attempt at validation. The major findings obtained in this research include that the proposed model is promising for evaluating the risk to Japanese health caused by the dietary intake of global radioactive fallout 137Cs, the 137Cs is taken up by Japanese mostly through farm products, the ingestion of 137Cs through imported foods is increasing, the risk to the Japanese health of inducing cancer by 137Cs internal exposure reached a maximum in 1963, gradually decreasing to the lowest present level, and the risk to infants is the highest.

A numerical model for the analysis and evaluation of global 137Cs fallout.

Fallout 137Cs from atmospheric nuclear detonation tests has been monitored worldwide since the late 1950's. The deviation and the correlation among these monitoring data were analyzed, and their surface deposition characteristics were estimated by the compartment model developed in this research. In the analysis, the scale of space (i.e., size of each compartment) and the degree of detail (i.e., number of compartments) were statistically determined using the global distribution data of 137Cs. The mathematical model was evaluated by comparing the numerically stimulated results with the fallout monitoring data including the 137Cs concentration in sea water. The major findings obtained in this research include that the deposition pattern of 137Cs is dependent on the latitude zone but not on the longitude, the mathematical model is promising for evaluating the dynamic performance of 137Cs in global atmospheric environment and its surface deposition, 137Cs is accumulated more in both the surface and deep ocean water of the North Pacific Ocean and the North Atlantic Ocean than that of other oceans, the 137Cs inventory is decreasing after the peak time in 1965, and the 137Cs inventory in the deep ocean water is decreasing more slowly than that in the surface ocean water.

Stratospheric HTO perturbations 1980-1983

Three perturbations of the stratospheric tritiated water burden have occurred. An atmosphericnuclear detonation in 1980 injected about 2.1 MCi. The massive eruptions of the volcano El Chichon may have contributed to a doubling of the removal rate in 1982. An unusually largewintertime exchange with the upper stratosphere may have occurred between 1982 and 1983. DOI: 10.1111/j.1600-0889.1985.tb00044.x

Cancer Incidence in an Area of Radioactive Fallout Downwind From the Nevada Test Site

Exposures in southwestern Utah to radioactive fallout (1951 through 1962) from atmospheric nuclear detonations at the Nevada Test Site (NTS) were followed by smaller exposures (1962 through 1979) from venting of underground nuclear detonations. The cancer incidence in a 1951 cohort (4, 125) of Mormon families in southwestern Utah near the NTS was compared with that of all Utah Mormons (1967 through 1975). There were 109 more cases of cancer than expected (288[observed]/179[expected]). Leukemia was most prominent early (1958 through 1966), with 19 cases, five times more than expected (3.6). The excess of leukemia persisted into the later period (1972 through 1980), with 12 cases observed, 3.4 expected. There was an increase in lymphoma. Excess cases of thyroid cancer appeared early and a notable excess appeared later (14/1.7). An excess of breast cancer was noted later (27/14). There were more cancers of the gastrointestinal tract than expected. There was an excess of melanoma (12/4.5), bone cancer (8/0.7), and brain tumors (9/3.9). A subgroup with history of acute fallout effects had a higher cancer incidence. That these cases can be associated with radiation exposures is supported by a comparison between groups of the ratio of cancers of more radiosensitive organs with all other types of cancer.

Radioactive nuclides in the marine environment--distribution and behaviour of 95Zr, 95Nb originated from fallout

To investigate behaviour of 95Zr, 95Nb in the marine environment, various samples have been collected and measured by means of Ge(Li) gamma-ray spectrometry and/or radiochemical analysis during a period from 1974 to 1982 at coastal area of Tokai-mura, Ibaraki prefecture. Concentration of the nuclides in seaweeds increased remarkably after atmospheric nuclear detonation by P.R. of China, and the activity ratio between the nuclides changed by time was not fit well by the transient decay equation. Concentration variation in sea water was smaller than that in sea weeds, and the minimum change in sea sediment. Increase of concentration in these environmental samples was observed in chronological order of sea water, sea weeds then sediment after detonations, suggesting that the uptake of the nuclides by these sea weeds from sea water is faster than that via root. Observed concentration factors on the nuclides by sea weeds were calculated from the observed concentrations in sea water and sea weeds. Maximum values on 95Zr and 95Nb were 2110, 2150, respectively for Ecklonia cava and Eisenia bicyclis.

Tritium injection and concentration distribution in the atmosphere

The use of environmental tritium as a water tracer has significantly increased our understanding of hydrological processes. Because of the large stratospheric reservoir of tritium produced by nuclear detonations and the relatively slow mixing rates between the stratosphere and the troposphere, studies of meteorological parameters of transport and diffusion can be made over many years. If the nuclear test ban treaty is observed and if no more large atmospheric nuclear detonations are conducted, the seasonal and annual changes in the atmospheric tritium distribution can give important information on the hydrological cycle and on meteorological effects. This paper relates stratospheric injection for a water tracer to the concentration of tracer in precipitation by means of meteorological parameters. A simplified model has been developed that relates injection, exchange, evaporation, condensation of water vapor, and tritium to meteorological parameters in the troposphere. Since the form of the model is general, tritium, fallout radionuclide, deuterium, and oxygen 18 data can be used as tracers to test the basic assumptions and to examine the physical processes that are occurring. The model was tested with meteorological data and tritium concentrations in precipitation from the IAEA/WMO World Network of sampling stations. The results of the initial application of the model to western Europe are presented.

Collection and determination of iodine-131 in the air.

Abstract The paper presents data on the collection and determination of iodine-131 from the air following the May, October, and December, 1966, atmospheric nuclear detonations by mainland China. The iodine-131 was collected on an alkaline barium-iodide-iodate impregnated filter and was determined by a destructive sulfuric acid distillation followed by collection and analysis of the gaseous iodine-131 evolved. Radioactivity measurements were made using a 3 × 3-inch NaI(TI) 1-inch-well crystal coupled to a 200-channel gamma analyzer. The variations in the amounts of iodine-131 recovered followed the gross beta activities for these periods. It is not known definitely if the iodine-131 collected in this manner includes the organically bound iodine-131. In future tests studies will be made to determine if all the forms of iodine-131 are collected by the barium-impregnated filter.

The 0.5 MeV gamma ray flux and the energy loss spectrum in CsI(Tl) at 4 g/cm 2

This paper describes one of a series of experiments designed to study the time variation of the 0.5 MeV gamma ray line at small atmospheric depths. The experiment was flown from Palestine, Texas on April 6, 1966 and yielded an equivalent omnidirectional flux of 0.29 ± 0.04 photons cm −2 sec −1 at an atmospheric depth of 4.0 ± 0.3 g/cm 2 for the line at 0.5 MeV as well as the continuous energy loss spectrum in a CsI gamma ray spectrometer from 0.2 to 0.9 MeV. An additional feature nominally at ~0.70 → 0.75 MeV was significantly present in the spectrum and corresponds to an equivalent omnidirectional flux of 0.10 ± 0.02 photons cm −2 sec −1, at 4 g/cm 2. The results are compared with a similar measurement in 1961 and it is found that the total flux of 0.5 MeV gamma rays in 1966 is about a factor of two larger than expected if one assumes this radiation is solely a result of interactions of charged primary cosmic rays in the atmosphere and follows the modulation of ion chamber intensity. Possible explanations of this discrepancy are discussed. Since atmospheric nuclear detonations may contribute to the observed features of the spectrum, it is necessary to consider seriously the possibility that the 0.5 MeV line, sometimes attributed to e +-- e − annihilation radiation, may have a ignificant time varying contribution from other sources. These include nuclear debris gamma rays from Ru 106 → Rh 106 → Pd 106 with energies of 0.51 MeV and 0.62 MeV; and Ru 103 → Rh 103 with an energy of 0.49 MeV. Gamma rays with an energy of 0.48 MeV from naturally occurring Be 7, which is produced by cosmic ray interactions in the atmosphere, may also contribute. Further experiments and improved instrumentation are required before definitive knowledge can be obtained concerning the high altitude flux of annihilation photons or the detailed nature of the gamma ray spectrum in the energy region from 0.2 MeV to 0.9 MeV.

Determination of particle size characteristics of old and fresh airborne fallout by graded filtration.

Using a collection system consisting of three graded filters placed in series, a study was conducted during the past year on the particle size characteristics of airborne fallout. Initial collections made during March and April 1964, consisted of fission products with an effective age of 440–550 days. Specific nuclides measured in these samples included 144Ce–144Pr 125Sb, 137Cs, 95Zr-95Nb, 54Mn, 106Ru-106Rh and 90Sr. Either gamma spectrometry or radiochemistry was used for quantitative estimations. During the latter part of October and throughout November 1964, a second series of collections were made which included fresh fission product material presumably resulting from the atmospheric nuclear detonation in mainland China. In addition to the above nuclides, these samples were analyzed for 141Ce, 132Te-132I, 131I, 103Ru-103Rh, 140Ba-140La and 89Sr. Differences in the particle size distribution of material on each filter were determined by optical microscopy. For older debris, at least 88 per cent of the total activity was associated with particles having diameters of less than approximately 1.75 μ. In fresh fallout, certain radionuclides were initially associated with larger particles. With time, this distribution gradually decreased due to settling out of larger active particles. Data are presented on the degree of radionuclide fractionation which occurred in each size group.