TY - JOUR
AU - Schwob, Claude R.
AB - Radioactive Decontamination 1 Claude R. Schwob , Ph.D. U. S. Naval Radiological Defense Laboratory ↵ 1 Presented at the Eighteenth Annual Conference of Teachers of Clinical Radiology, Chicago, Feb. 10, 1951. Excerpt An atomic bomb , in one sense, may be considered to be a device for efficiently and rapidly producing untold amounts of radiation and radioactive substances. If the radioactive material so produced is spread over an area, that area is said to be contaminated. Once deposited, the material continues to give off harmful rays for a long time, and nothing now known to science can stop this process. This so-called residual radiation is as deadly as the instantaneous radiation: it has been calculated that at the time of deposition on some of the Bikini-Baker target ships, the resulting radioactivity was of the order of 50,000 r per hour. Not only are surfaces of objects contaminated, but so is dust. The latter is often disturbed during and immediately after a burst and can find its way inside the body. Thus, we have both an external and internal hazard. I need only refer to the statements of the previous speakers to establish the importance of the problems posed by the residual radiation. Fortunately, even in a full-scale atomic war, contamination can be expected fairly rarely. There are ways of using atomic bombs to give maximum destruction and immediate effects, without contamination. Let us consider this point. Occurrence of Contamination First of all, how and under what circumstances can we expect to be faced with contamination? In an air burst, which incidentally is considered the most efficient for destruction, the danger of contamination is so small that it may be neglected. However, underwater, underground, and surface bursts will cause widespread contamination. In such instances, the fission products are trapped by the water or the soil and, instead of being dissipated in the stratosphere, are returned to the surroundings by the force of gravity. The contaminants will be deposited on surfaces and any exposed material or equipment. The vagaries of individual situations will determine just how this contamination will be distributed. In general, however, one may cite the following guiding rules: There will be more contamination on horizontal surfaces than on vertical ones. There will be more contamination on rough, porous surfaces such as cloth, rope, and concrete, than on smooth hard ones such as glass, plastics, polished metals, and paint. The greater the amount of contamination on a given surface, the greater the fraction that will be readily removed by simple means. This last concept requires a bit of amplification. It has been observed that contamination removal becomes increasingly difficult as the removal proceeds. We interpret this to mean that only that part of the contamination which is in immediate contact with the surface is held by strong forces. The remainder of the contamination is, so-to-speak, merely shoveled on, and rather loosely held. Hence, any ordinary cleaning procedure is generally successful in treating it. Copyrighted 1951 by The Radiological Society of North America, Inc.
TI - Radioactive Decontamination
JF - Radiology
DO - 10.1148/56.5.670
DA - 1951-05-01
UR - https://www.deepdyve.com/lp/radiological-society-of-north-america-inc/radioactive-decontamination-VhKHAa1fT3
SP - 670
VL - 56
IS - 5
DP - DeepDyve
ER -