Radioactive decay radiation from

Irradiation stability. Any solidified HLW will be exposed to energetic radiation from radioactive decay of fission products and actinides. Part of the radiation energy is dissipated in elastic collisions with atoms from the solid material, thereby displacing them and causing radiation damage. This may affect macroscopic properties such as mechanical or chemical ones, and it may cause storage of energy. 

Table 32-1 lists the most important (from a chemist s viewpoint) types of radiation from radioactive decay. Four of these types — alpha particles, beta particles, gamma-ray photons, and X-ray photons —can be detected and recorded by the detector systems described in Section 12B-4. Most radittchcniical methods are based on counting the electronic signals produced when these decay particles or photons strike a radiation detector. 

Radiations from radioactive decay cause the material they pass through to become ionized, hence the term ionizing radiations . The effect on body tissues depends on ... 

Most of the known large uranium districts in the world have been discovered radiometrically by airborne or ground gross count radiometric surveys where the high-energy gamma radiation from radioactive decay of the series ( Bi), the... 

In terms of atomic spectrometry, NAA is a method combining excitation by nuclear reaction with delayed de-excitation of the radioactive atoms produced by emission of ionising radiation (fi, y, X-ray). Measurement of delayed particles or radiations from the decay of a radioactive product of a neutron-induced nuclear reaction is known as simple or delayed-gamma NAA, and may be purely instrumental (INAA). The y-ray energies are characteristic of specific indicator radionuclides, and their intensities are proportional to the amounts of the various target nuclides in the sample. NAA can thus... 

There are other sources of radiation from the decay of radioactive elements in the Earths cmst. 

Sensitivity of Detector What types of radiation will the detector detect For example, solid scintillation detectors are normally not used to detect a particles from radioactive decay because the a particles cannot penetrate the detector covering. 

That brings up the second thing, which is that there are acceptable levels of radiation. We are constantly bombarded with naturally occurring radiation from outer space and natural elements in the Earth. YouVe been bombarded with particles from radioactive decay since you were born. Of course, even naturally occurring radiation can be harmful. In my part of the country, it s wise to check the levels of radon underneath your home because its radioactive particles can cause health problems. 

The second type of corpuscular radiation in radioactive decay is B"-radiation. In this case, negatively charged electrons are ejected from the radionuclide. The atomic mass number of the radionuclide does not change. 

The characteristics of the measuring techniques will depend on whether the quantity to be measured is the concentration of radon (be it in air, in watei or in soil) or of the radon decay products. Both these measurements are based on the detection of radiation emitted from radioactive decay in combination with a suitable sampling technique. The whole spectrum of radiation detectors could be used, but most methods rely on detection of a-particles some are based on detection of y-emissions and only a few utilize jS-decays. 

Impurities from decay products (i.e., from radioactive decay and from radiation-induced decay of chemical compounds) can interfere with the activity measurements, or with the chemical reactions employed to process the sample. Radionuclide purity is a function of time. 

The use of radioactive isotopes has had a profound effect on the practice of medicine. Radioisotopes were first used in medicine in the treatment of cancer. This treatment is based on the fact that rapidly dividing cells, such as those in cancer, are more adversely affected by radiation from radioactive substances than are cells that divide more slowly. Radium-226 and its decay product radon-222 were nsed for cancer therapy a few years after the discovery of radioactivity. Today gamma radiation from cobalt-60 is more commonly used. 

The objective of the nuclear industry is to produce energy in the forms of heat and radiation. For heat applications, the nuclear fuel has a very high specific energy content that has two principal uses, for military explosives and for electricity generation. For radiation applications the emissions from radioactive decay of unstable nuclides are employed in research, medicine, and industry for diagnostic purposes and for chemical reaction initiation. 

The same chemical separation research was done on thorium ores, leading to the discovery of a completely different set of radioactivities. Although the chemists made fundamental distinctions among the radioactivities based on chemical properties, it was often simpler to distinguish the radiation by the rate at which the radioactivity decayed. For uranium and thorium the level of radioactivity was independent of time. For most of the radioactivities separated from these elements, however, the activity showed an observable decrease with time and it was found that the rate of decrease was characteristic of each radioactive species. Each species had a unique half-life, ie, the time during which the activity was reduced to half of its initial value. 

There are four modes of radioactive decay that are common and that are exhibited by the decay of naturally occurring radionucHdes. These four are a-decay, j3 -decay, electron capture and j3 -decay, and isomeric or y-decay. In the first three of these, the atom is changed from one chemical element to another in the fourth, the atom is unchanged. In addition, there are three modes of decay that occur almost exclusively in synthetic radionucHdes. These are spontaneous fission, delayed-proton emission, and delayed-neutron emission. Lasdy, there are two exotic, and very long-Hved, decay modes. These are cluster emission and double P-decay. In all of these processes, the energy, spin and parity, nucleon number, and lepton number are conserved. Methods of measuring the associated radiations are discussed in Reference 2 specific methods for y-rays are discussed in Reference 1. 

Unstable isotopes decompose (decay) by a process referred to as radioactivity. Ordinarily the result is the transmutation of elements the atomic number of the product nucleus differs from that of the reactant. For example, radioactive decay of produces a stable isotope of nitrogen, N. The radiation given off (Figure 2.6) may be in the form of—... 

Beer s law The absorbance of electromagnetic radiation by a sample is proportional to the molar concentration of the absorbing species and the length of the sample through which the radiation passes, beta (P) decay Nuclear decay due to fi-particle emission, beta (P) particle A fast electron emitted from a nucleus in a radioactive decay. 

Total exposures vary considerably with human activities as well. Frequent flyers, for example, receive higher doses of radiation because the intensity of cosmic radiation is significantly greater at high altitude than it is at ground level. Residents in locations such as Montana and Idaho, where there are uranium deposits, receive higher doses of radiation from radon, one of the radioactive decay products of uranium. 

The presence of radiation in the workplace - which is an inevitable consequence of the radioactivity of uranium - requires that additional safety precautions be taken over and above those observed in other similar workplaces. There are generally three sources from which radiation exposure may occur (i) radiation emitted from uranium ore in-situ and/or during handling (ii) airborne radiation resulting from the decay of radon gas released from the ore and uranium dust and (iii) contamination by ore dust or concentrate. Radiation levels around uranium mining and milling facilities are quite low - for the most part only a few times the natural background levels - and they decrease rapidly as the distance from... 

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