In situ production and migration of 129I in the Stripa granite, Sweden☆
In situ production and migration of 129I in the Stripa granite, Sweden☆
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DOI：
10.1016/0016-7037(89)90302-5
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发表时间：
1989-08
影响因子：
5
通讯作者：
J. Fabryka-Martin;S. Davis;D. Elmore;P. Kubik
中科院分区：
文献类型：
--
作者：
J. Fabryka-Martin;S. Davis;D. Elmore;P. Kubik
天然129 I和36 Cl的地下水从Stripa花岗岩，瑞典，浓度测定加速器质谱法。129 I的值范围为1× 10 6 ~ 2× 10 8原子1− 1，比1945年前雨水中2× 10 4原子1− 1的估计背景浓度高出几个数量级。以129 I 127 I的比值表示，数值范围为3× 10− 12至2× 10− 10，而1945年前的雨水约为1× 10− 12。比率和浓度一般随取样深度的增加而增加，取样深度从地表以下360米到> 1000米不等。129 I在水中的积累是由于地下生产的自发裂变的238 U在花岗岩基质中的微裂缝和随后的转移，这129 I通过扩散到裂缝构成的流动系统的花岗岩。在质量为129的自发裂变产额和稳态质量通量的假设中，不确定性阻止了对129 I转移速率的定量估计。
Concentrations of natural 129 I and 36 Cl in ground water from the Stripa granite, Sweden, were determined by accelerator mass spectrometry. The 129 I values range from 1× 10 6 to 2× 10 8 atoms 1− 1, orders of magnitude greater than the estimated background concentration in pre-1945 rainwater of 2× 10 4 atoms 1− 1. Expressed as a ratio 129 I 127 I, values range from 3× 10− 12 to 2× 10− 10, compared to about 1× 10− 12 in pre-1945 rainwater. Ratios, as well as concentrations, generally increase with sample depth, which ranges from 360 to> 1000 m below the surface. The accumulation of 129 I in the water is attributed to subsurface production by spontaneous fission of 238 U in micro-fractures in the granite matrix and subsequent transfer of this 129 I by diffusion into fractures constituting the flow system of the granite. Uncertainties in the spontaneous-fission yield at mass 129 and in the assumption of steady-state mass flux prevent quantitative estimates of the rate of 129 I transfer.