Analysis on the influence of forest soil characteristics on radioactive Cs infiltration and evaluation of residual radioactive Cs on surfaces
Analysis on the influence of forest soil characteristics on radioactive Cs infiltration and evaluation of residual radioactive Cs on surfaces
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森林土壤特性对放射性铯渗透的影响分析及地表放射性铯残留评价
DOI：
10.1007/s10661-018-6571-0
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发表时间：
2018
影响因子：
3
通讯作者：
Shimomura Ryohei
中科院分区：
文献类型：
--
作者：
Mori Yoshitomo;Yoneda Minoru;Shimada Yoko;Fukutani Satoshi;Ikegami Maiko;Shimomura Ryohei
我们调查了放射性铯，灼烧损失，阳离子交换量（CEC）在五种类型的森林土壤采样刮板深度剖面。然后，我们模拟了监测的深度剖面的隔室模型，以烧失量作为参数的基础上，实验结果表明，烧失量和CEC之间的正相关性。计算值与监测值基本一致，但在土层中部存在一定差异。基于表面剂量率和表面污染浓度的去污数据，我们新定义了一个表面残留指数（SRI）来评价表面上残留的放射性Cs。森林和未铺砌道路的SRI值趋于逐渐减小，并且森林和未铺砌道路上的SRI值比铺砌道路上的小得多。据推测，放射性铯在核电站事故发生18个月后已经渗入地下，而且下沉还在继续。在铺砌的道路上测得的SRI值表明，放射性铯仍然存在于表面上，尽管在监测期结束时观察到了逐渐的渗透。SRI值被认为是有效的，在现场的去污活动的现场残留放射性Cs的大致情况迅速掌握。SRI值可用于实际的污染工作后，做进一步的研究，以阐明SRI之间的关系，如放射性Cs在各种类型的对象的渗透。
We investigated the depth profiles of radioactive Cs, ignition loss, and cation exchange capacity (CEC) in five types of forest soils sampled using scraper plates. We then simulated the monitored depth profiles in a compartment model, taking ignition loss as a parameter based on experimental results showing a positive correlation between ignition loss and the CEC. The calculated values were comparable with the monitored values, though some discrepancy was observed in the middle of the soil layer. Based on decontamination data on the surface dose rate and surface contamination concentration, we newly defined a surface residual index (SRI) to evaluate the residual radioactive Cs on surfaces. The SRI value tended to gradually decrease in forests and unpaved roads and was much smaller in forests and on unpaved roads than on paved roads. The radioactive Cs was assumed to have already infiltrated underground 18 months after the nuclear power plant accident, and the sinking was assumed to be ongoing. The SRI values measured on paved roads suggested that radioactive Cs remained on the surfaces, though a gradual infiltration was observed towards the end of the monitoring term. The SRI value is thought to be effective in grasping the rough condition of residual radioactive Cs quickly at sites of decontamination activity in the field. The SRI value may be serviceable for actual contamination works after further research is done to elucidate points such as the relation between the SRI and the infiltration of radioactive Cs in various types of objects.