Radioactive decay engineering

Another case of practical interest in nuclear engineering is the buildup and decay of fission products formed in a nuclear reactor operating at a steady fission rate for a time T and that have been removed from the reactor and aUowed to undergo radioactive decay for an additional time. The schematic diagram for continuous production of the first member of the drain at rate P is... 

Where the reactor circuit is breached, however, substantial quantities of fission products may well escape from the circuit to the reactor containment or auxiliary building. Further removal of fission products is then likely within the containment by deposition onto the containment walls, or upon water droplets in the containment atmosphere, and of course by radioactive decay. For fission products, other than the noble gases, deposition on walls is likely to be the dominant process, in the absence of engineered safeguards. Deposition is governed by a deposition velocity (or mass transfer coefficient) V according to the relation... 

In the 1970 s, interplanetary spacecraft ranged far from the Sun and strained the capabilities of solar panels to provide sufficient electrical power. Spacecraft engineers harnessed the energy of radioactive decay to power deep-space missions and to keep the spacecraft warm so far from the Sun. Missions to Mercury and Venus, so near the Sun, posed the opposite challenge of keeping the spacecraft from overheating. 

Low level waste from commercial facilities is buried on site. The Nuclear Regulatory Commission (NRC) has projected the activities and volumes of low level radioactive waste from all sources buried at commercial sites to the year 2000 using information from the Idaho National Environmental and Engineering Laboratory (INEEL) waste retrieval project and assuming that the waste disposal practices then used would continue into the future. The 20-year decayed 241Am and 243Am concentrations were estimated to be 380 and 230 pCi/m3 (14 and 8.5 Bq/m3), respectively (Kennedy et al. 1985). 

The burning of the uranium-based nuclear fuel causes a cavalcade of chemical and physical transformations. Nuclear reactions lead to the formation of a variety of actinide elements, for example, Np, Pu, Am, and Cm, as radioactive fission products. As a result of the production of these highly radioactive elements, burnt nuclear fuel must be allowed to cool until the short-hved isotopes decay away and reduce the thermal generation. The cooling typically takes place in either water ponds or engineered dry casks/facilities. 

Decay di- ka [ME, fr. ONE decatr, fr. LL decadere to fall, sink, fr. L de- -f cadere to fall] (15c) n. Diminution of a radioactive substance due to nuclear emission of alpha or beta particles, gamma rays or positrons. Giambattista A, Richardson R, Richardson RC, Richardson B (2003) College physics. McGraw-Hill Science/Engineering/Math, New York. 

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