Radioactive materials sources

Hazardous chemical waste is defined in RCRA regulations as a solid waste that exhibits the characteristic of ignitability, corrosivity, reactivity, or toxicity, or is a specifically listed waste. The definition of hazardous waste specifically excludes radioactive material (source, special nuclear, or byproduct material) defined in AEA. 

Hazard (Powder) Dangerous fire risk, ignites spontaneously in air. Highly toxic, radioactive material, source of ionizing radiation. TLV (including metal and all compounds, as uranium) 0.2 mg/m3 STEL 0.6 mg(U)/m3. 

Precaution (Powd.) dangerous fire risk, ignites spontaneously in air radioactive material source of ionizing radiation Uses Source of fissionable isotope uranium-235, source of plutonium by neutron capture, electric power generation... 

Worker exposures to radioactive material sources in Zone 2A and Room 109 must be maintained ALARA. Shielding design and administrative control of radioacBve material sources in Zone 2A and Room 109 maintain worker exposures below an average of 0.5 mrem per hour in continuously occupied 000 hours per year) areas of the HCF. 

A reasonable and much simplified approach could entail a reduction in the number of the criteria described above, as for most research reactors the application of the criteria for facility classification shows a strong correlation between the risk associated with the facility and its installed power or radioactive inventory. This correlation might simplify the classification process at the beginning of the design. Clearly such assumptions have to be assessed in the safety assessment phase and justified in the safety analysis report. Table 2 provides an example of such a simplified approach based on the power rating of a research reactor or on the quantity and form of radioactive material (source term) in the facility. In the case of eonflict, the most stringent criteria can be applied. 

Fluorine, which does not occur freely in nature except for trace amounts in radioactive materials, is widely found in combination with other elements, accounting for ca 0.065 wt % of the earth s cmst (4). The most important natural source of fluorine for industrial purposes is the mineral fluorspar [14542-23-5] CaF2, which contains about 49% fluorine. Detailed annual reports regarding the worldwide production and reserves of this mineral are available (5). A more complete discussion of the various sources of fluorine-containing minerals is given elsewhere (see Fluorine compounds, inorganic). 

The safety record for transport of radioactive materials including spent fuel and wastes is excellent. Information about transportation of radioactive materials including waste is managed by DOE. Codes such as RADTRAN that can calculate pubHc radiation dose owing to the passage of shipments have been developed. The maximum dosage from such shipments is a very small fraction of the typical annual radiation dose from all other sources. 

Conservation of Energy. Because the naturally occurring radioactive materials continued to emit particles, and thus the associated energy, without any decrease in intensity, the question of the source of this energy arose. Whereas the conservation of energy was a firmly estabUshed law of physics, the origin of the energy in the radioactivity was unknown. 

Radioactivity. Methods based on the measurement of radioactivity belong to the realm of radiochemistry and may involve measurement of the intensity of the radiation from a naturally radioactive material measurement of induced radioactivity arising from exposure of the sample under investigation to a neutron source (activation analysis) or the application of what is known as the isotope dilution technique. 

A sampler should be familiar with the source of all the leachates at a site before removing a sample. If radioactive materials are present, extra care must be taken. 

Figure 32.9 Survival time and associated mode of death of selected mammals after whole-body doses of gamma radiation. (Modified from Hobbs, C.H. and R.O. McClellan. 1986. Toxic effects of radiation and radioactive materials. Pages 669-705 in C.D. Klaassen, M.O. Amdur, and J. Doull [eds.]. Casarett and Doull s Toxicology. Third Edition. Macmillan, New York United Nations Scientific Committee on the Effects of Atomic Radiation [UNSCEAR]. 1988. Sources, Effects and Risks of Ionizing Radiation. United Nations, New York. 647 pp.)...

Fallen in the hands of criminals, which as a rule have a very remote notion on the danger of ionizing radiation, radioactive sources become a serious threat for the life and health of the terrorists themselves, as well as of casual persons. And the attempt to extract the ampoule with the radioactive source from its protection block is equal to expose oneself to radiation. Besides, in the event of destruction of the ampoule containing radioactive material, radioactive contamination of a large territory can occur. Such an incident happened already in Taromskoe suburb of Dnepropetrovsk. 

The use of radioactive ionization sources in areas subject to explosion or fire is undesirable because of the potential for area contamination with radioactive material which could be disseminated in the event of an explosion or fire. With proper precautions, however, electrical ionizing systems can be safely and effectively utilized while processing electrostatically sensitive energetic materials. Ions are generated electrically by corona discharge... 

For many of the analytical techniques discussed below, it is necessary to have a source of X-rays. There are three ways in which X-rays can be produced in an X-ray tube, by using a radioactive source, or by the use of synchrotron radiation (see Section 12.6). Radioactive sources consist of a radioactive element or compound which spontaneously produces X-rays of fixed energy, depending on the decay process characteristic of the radioactive material (see Section 10.3). Nuclear processes such as electron capture can result in X-ray (or y ray) emission. Thus many radioactive isotopes produce electromagnetic radiation in the X-ray region of the spectrum, for example 3He, 241Am, and 57Co. These sources tend to produce pure X-ray spectra (without the continuous radiation), but are of low intensity. They can be used as a source in portable X-ray devices, but can be hazardous to handle because they cannot be switched off. In contrast, synchrotron radiation provides an... 

In New York state a reprocessing plant near Buffalo began to reprocess nuclear wastes in 1966. After 6 years Nuclear Fuel Services (NFS), a subsidiary of W.R. Grace s Davison Chemical Company, abandoned the facility. There were 2 million cubic feet of radioactive material left behind along with 600,000 gallons of radioactive liquid waste that was seeping into a creek that flows into Lake Erie the source of drinking water for Buffalo. The cost of cleanup was estimated to be 1 billion. 

The other types of radioactive materials cited in this section (medical industry and food industry sources) produce significantly lower activity levels than fuel from a nuclear power plant. However, these sources of radioactive materials may be appealing to terrorists because they are far more accessible. Thousands of hospitals, medical treatment facilities, and food industry plants scattered across the U.S. are protected by relatively low levels of security. 

Nuclear fuel and associated waste products also include plutonium and enriched uranium (<20% U-235) and associated waste or fission products that emit intense radiation and can pose significant threats if dispersed with conventional explosives (i.e., by a dirty bomb). Industrial sources include a range of devices used in geological investigation and radiography, and may also pose significant hazards if dispersed by a dirty bomb. Examples of radioactive materials that could be used in a dirty bomb include ... 

Personnel working in some programs at the Los Alamos National Laboratory (LANL) may handle radioactive materials that, under certain circumstances, could be taken into the body. Employees are monitored for such intakes through a series of routine and special bioassay measurements. One such measurement involves a thermal ionization mass spectrometer. In this technique, the metals in a sample are electroplated onto a rhenium filament. This filament is inserted into the ion source of the mass spectrometer and a current is passed through it. The ions of the plutonium isotopes are thus formed and then accelerated through the magnetic held. The number of ions of each isotope are counted and the amount of Pu-239 in the original sample calculated by comparison to a standard. 

Radiation therapy The use of high-energy radiation from x-rays, gamma rays, neutrons, and other sources to kill cancer cells and shrink tumors. Radiation may come from a machine outside the body (external-beam radiation therapy), or it may come from radioactive material placed in the body in the area near cancer cells (internal radiation therapy, implant radiation, or brachytherapy). Systemic radiation therapy uses a radioactive substance, such as a radiolabeled monodonal antibody, that circulates throughout the body. Also called radiotherapy, [nih]... 

Use nuclear power, medical X-rays, medical diagnostics, scientific research, cancer treatment, cathode ray tube displays Source radon, X-rays, radioactive materials produce alpha, beta, and gamma radiation, cosmic rays from the sun and space Recommended daily intake none (not essential)... 

Time - Limit the amount of time you spend near the source of radiation. One of the easiest examples is that you avoid getting sunburned by limiting the amount of time in bright sunlight. This same principle applies to ionizing radiation such as a radioactive material. 

The SI unit of activity is the becquerel (Bq) 1 Bq = 1 transformation/second. Since activity is proportional to the number of atoms of the radioactive material, the quantity of any radioactive material is usually expressed in curies, regardless of its purity or concentration. The transformation of radioactive nuclei is a random process, and the rate of transformation is directly proportional to the number of radioactive atoms present. For any pure radioactive substance, the rate of decay is usually described by its radiological half-life, T r i.e., the time it takes for a specified source material to decay to half its initial activity. The activity of a radionuclide at time t may be calculated by A = A° e ° rad where A is the activity in dps, A ° is the activity at time zero, t is the time at which measured, and T" is the radiological half-life of the radionuclide. It is apparent that activity exponentially decays with time. The time when the activity of a sample of radioactivity becomes one-half its original value is the radioactive half-life and is expressed in any suitable unit of time. 

---