Barton T P, Ziemer P L
Health Phys. 1986 May;50(5):581-8. doi: 10.1097/00004032-198605000-00001.
Measurements of the emanation coefficients of 222Rn from coal ash were performed. Samples of coal ash from a stoker-fired furnace were mechanically sized into four categories. The mean 226Ra concentration of these categories ranged from 11.82-16.77 dpm g-1 and increased as a function of decreasing particle size. The mean bulk density and mean specific gravity of these categories ranged from 0.488-0.944 g cm-3 and 2.017-2.390 g cm-3, respectively, and both increased as a function of decreasing particle size. Samples of coal ash from four pulverized coal-fired furnaces were obtained, and demonstrated mean 226Ra concentrations ranging from 6.44-7.59 dpm g-1. The mean bulk density and mean specific gravity of these samples ranged from 1.254-1.520 g cm-3 and 2.357-2.588 g cm-3, respectively. Construction of chambers and methods for measuring 222Rn emanation coefficients are described. The measured emanation coefficient is shown to be insensitive to ingrowth time at times greater than three days. Measurements of emanation coefficients from ash samples were conducted at moisture contents of 0, 1.0, 10, 20 and 40% moisture by weight, and showed an increase in the emanation coefficient as a function of moisture content up to about 20% moisture by weight. Above 20% moisture content, most samples showed a trend toward decreasing emanation coefficients. The fractionated ash samples showed an increase in the emanation coefficient as a function of decreasing particle size. An experiment was also conducted which confirmed that sample depth was insignificant in explaining the observed emanation coefficient over the range of depths used in the other experiments.
对煤灰中222Rn的析出系数进行了测量。对层燃炉的煤灰样品进行机械筛分，分为四类。这些类别中226Ra的平均浓度范围为11.82 - 16.77 dpm g-1，并随颗粒尺寸减小而增加。这些类别的平均堆积密度和平均比重分别为0.488 - 0.944 g cm-3和2.017 - 2.390 g cm-3，且均随颗粒尺寸减小而增加。获取了四个煤粉炉的煤灰样品，其226Ra平均浓度范围为6.44 - 7.59 dpm g-1。这些样品的平均堆积密度和平均比重分别为1.254 - 1.520 g cm-3和2.357 - 2.588 g cm-3。描述了测量222Rn析出系数的腔室构建和方法。结果表明，在大于三天的时间里，测量的析出系数对生长时间不敏感。在重量含水量为0、1.0、10、20和40%的情况下对灰样的析出系数进行了测量，结果表明，析出系数随含水量增加而增加，直至重量含水量约为20%。含水量超过20%时，大多数样品的析出系数呈下降趋势。分级后的灰样析出系数随颗粒尺寸减小而增加。还进行了一项实验，证实了在其他实验所使用的深度范围内，样品深度对观测到的析出系数影响不大。
