Nuclear weapon tests environments

The major source of plutonium in natural waters is the atmospheric fallout from nuclear weapons tests. Fallout plutonium is ubiquitous in marine and freshwater environments of the world with higher concentrations in the northern hemisphere where the bulk of nuclear weapons testing occurred(3). Much of the research on the aquatic chemistry of plutonium takes place in marine and freshwater systems where only fallout is present. 

Radioactive substances The principal sources of radionuclides released into the environment include nuclear weapon testing fallout from accidents such as the Chernobyl accident in 1986 or from foundering of nuclear submarines from the dumping of nuclear waste into the deep ocean and from discharges from nuclear power plants and nuclear reprocessing plants. 

Among common radionuclide sources are the natural environment, fallout from nuclear weapon tests, effluents from nuclear research laboratories, the nuclear power fuel cycle, radiopharmaceutical development, manufacturing, and various application, teaching and research uses. Decontamination and decommissioning activities at former nuclear facilities and the potential of terrorist radionuclide uses are current topics of interest for radioanalytical chemistry laboratories. Simplified information on the numerous radionuclides is conveniently found in Charts of the Nuclides such as Nuclides and Isotopes (revised by J. R. Parrington, H. D. Knox, S. L. Breneman, E. M. Baum, and F. Feiner, 15th Edition, 1996, distributed by GE Nuclear Energy). 

A number of artificial radionuclides are produced as a result of activation during nuclear weapons tests, operation of reprocessing plants and reactors in nuclear power stations, and in nuclear studies. Modem radioanalytical techniques have enabled activation products such as Na, Cr, " Mn, Fe, °Co, Ni Zn, °Ag, and " Sb to be detected in the environment [28,29]. Stainless steel containing iron, nickel, and cobalt is an important material in nuclear power reactors and is used to constmct nuclear test devices or their supporting stmctures [30,31]. During neutron activation of the stable isotopes of cobalt, radioactive isotope °Co (J = 5.27 years) is produced. It is a beta emitter and decays into °Ni, with energy niax of... 

This chapter focuses on the interactions of radionuclides with geomedia in near-surface low-temperature environments. Due to the limitations on the chapter length, this review will not describe the mineralogy or economic geology of uranium deposits the use of radionuclides as environmental tracers in studies of the atmosphere, hydrosphere, or lithosphere, the nature of the nuclear fuel cycle or processes involved in nuclear weapons production. Likewise, radioactive contamination associated with the use of atomic weapons during World War 11, the contamination of the atmosphere, hydrosphere, or lithosphere related to nuclear weapons testing, and concerns... 

The IAEA campaign corroborated the extensive data already available and provided additional scientific information. The activity concentrations of radionuclides in the terrestrial and aquatic environments are generally low and comparable with reported concentrations of the same radionuclides at similar atolls where no nuclear weapon testing took place. 

Plutoqium present in the earth at its time of formation has long since decayed because of its relatively short half-life (/j/2 = 24,360 y for Pu). Most Pu in the environment is derived from nuclear-weapons testing or from nuclear wastes (cf. Hanson 1980 Kathren 1984). However, small amounts of natural Pu are produced through neutron capture by (see Eq [13.13]). Analyses of Pu in a number of uranium ore deposits have shown it to be near secular equilibrium with (see Section 13.1.6), with a weighted average Pu/U atomic ratio of (3.1 0.4) x 10, which nearly equals (3.0 0.5) x 10 , the ratio at secular equilibrium (Curtis et al. 1992,1994). 

There are various sources of radiocesium in the environment. The input from atmospheric weapons testing in the mid-twentieth century leads to the most widespread and homogeneous contamination of soil and water. The accumulated contribution of Cs in Europe from this source is estimated to be about 1000 Bq m 2. The fairly uniform deposition of Cs from fallout followuig the nuclear weapons testing has led to the widespread use of this isotope as a tracer of erosion (Ritchie and McHenry, 1990 Agudo, 1998). The accident that occurred at the Chernobyl nuclear plant in April 1986 led to more localized contamination. The events that led to this accident and the consequences have been widely... 

We discussed the sources of artificial occurrence of " Tc at the beginning of this chapter and demonstrated that the nuclear fuel cycle is the predominant source of Tc in the environment. Other, much less important, sources are the fallout from nuclear weapons testing, the Chernobyl accident, nuclear power production and the radiopharmaceutical use of the metastablc "Tc decaying to ground state Tc. The natural occurrence of Tc formed in the earth s crust by spontaneous fission of and neutron-induced fission of in uranium ores are negligible. 

Before natural tritium could be fully exploited for studies of natural water systems, tritium from anthropogenic sources (mainly nuclear weapon tests) was added to the atmosphere in considerable amounts. By the mid 1960s the natural background of tritium in precipitation was practically masked by so-called bomb tritium (e.g., Weiss et al. 1979 Fig. 1). For the past 4 to 5 decades, bomb tritium severely limited the use of natural tritium as a tracer because only few uncontaminated tritium data are available from the pre-bomb era. However, bomb tritium offered a new tool for studies of water movement in natural system. It is equivalent to a dye that was introduced into the environment on a global scale at a relatively well-known rate. Most of the bomb tritium was added to the environment in three pulses during 1954, 1958-1959 and, predominantly, 1963. 

In this paragraph we briefly describe some of the largest anthropogenic sources causing far field effects, i.e. nuclear weapons tests and nuclear power plant accidents. The cause of the releases is discussed in Chapter 19. Chapter 22 discusses both near and far field effects in further detail, particulary with regard to chemical properties liquid releases from nuclear power plants, dissolution of solidified nuclear waste and of fall-out particles, migration in the environment, and possible consequences. 

Anthropogenic radioactive contamination of the marine environment has several sources disposal at sea, discharges to the sea, accidental releases and fallout from nuclear weapon tests and nuclear accidents. In addition, discharge of naturally occurring radioactive materials (NORM) from offshore oil and gas production is a considerable source for contamination. 

Routine operations of nuclear reactors and other installations in the nuclear fuel cycle release small amounts of radioactive material to the air and as liquid effluents. However, the estimated total releases of °Sr, I and Cs over the entire periods of operation are negligible compared to the amounts released to the environment due to nuclear weapon tests. 

Nuclear weapon tests in the atmosphere from 1945 to 1980 have caused the greatest man-made release of radioactive material to the environment. The most intensive nuclear weapon tests took place before 1963 when a test-ban treaty signed by the UK, USA and USSR came into force. France and China did not sign the treaty and continued some atmospheric tests, but after 1980 no atmospheric tests have taken place. 

Iodine-129 is an environmentally important radionuclide with a half life of 1.57 X lO y. The three main sources of in the environment are nature, nuclear weapons testing and power reactor operation. NAA is usually carried out by measuring the ratio of to after neutron activation by the following nuclear reactions with reactor neutrons ... 

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