TRANSFER OF SELLAFIELD-DERIVED NP-237 TO AND WITHIN THE TERRESTRIAL ENVIRONMENT
TRANSFER OF SELLAFIELD-DERIVED NP-237 TO AND WITHIN THE TERRESTRIAL ENVIRONMENT
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DOI：
10.1016/0265-931x(91)90074-p
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发表时间：
1991-01-01
影响因子：
2.3
通讯作者：
DUNCAN, HJ
中科院分区：
文献类型：
--
作者：
HURSTHOUSE, AS;BAXTER, MS;DUNCAN, HJ
从英国西坎布里亚郡收集的土壤剖面中的Np-237的垂直分布已被ICP-MS测量。它们显示，在一般情况下，指数下降与深度，类似于其他超铀和裂变产物核素。 任何土壤样品中的最大Np-237放射性浓度为2.87 +/- 0.68（2-sigma）Bq kg-1（干），对于0-5 cm的潜育土，而同一样品中的Pu-239、Pu-240为3660 +/- 460（2-sigma）Bq kg-1（干）。 一个显着的比例，总的Np-237库存观察在深度在大多数网站，这意味着更大的流动性的镎比其他超铀核素内的配置文件studied.Consideration的核素比率，使用BNFL塞拉菲尔德液体排放作为主要源项，表明，第一近似，Np-237是不太绑定到粒子比Pu-239，Pu-240和Am-241。 似乎有一个更大的倾向，表现得更保守的NP-237比其他超铀元素释放到IrishSea.At一个采样点，转移到陆地环境是由海水的直接入侵为主。 在向陆地过渡的过程中，相对于Pu，Am和Cs，Np-237通过再活化从固相中“丢失”。 通过对土壤和沉积物样品进行连续沥滤的进一步研究证实，与钚、Am或Cs相比，Np-237的更大比例与更容易获得的组分（可交换的和专门吸附的）有关。 然而，有机相在Np保留和结合方面仍然是重要的。
The vertical distributions of Np-237 in soil profiles collected from west Cumbria, UK, have been measured by ICP-MS. They show, in general, exponential decreases with depth, similar to those of the other transuranic and fission product nuclides. The maximum Np-237 activity concentration in any of the soil samples was 2.87 +/- 0.68 (2-sigma) Bq kg-1 (dry) for the 0-5 cm section of a gley soil, compared to 3660 +/- 460 (2-sigma) Bq kg-1 (dry) for Pu-239, Pu-240 in the same sample. A significant proportion of the total Np-237 inventory is observed at depth in most sites, implying a greater mobility of neptunium than other transuranium nuclides within the profiles studied.Consideration of nuclide ratios, using BNFL Sellafield liquid discharges as the primary source term, indicates that, to a first approximation, Np-237 is less bound to particles than Pu-239, Pu-240 and Am-241. There appears to be a greater tendency for Np-237 to behave more conservatively than the other transuranics on release to the Irish Sea.At one sampling site, transfer to the terrestrial environment is dominated by direct incursion of seawater. During this transition to land, Np-237 is 'lost', relative to Pu, Am and Cs, from the solid phase by remobilization. Further study by sequential leaching of soil and sediment samples confirms that a much greater proportion of the Np-237 is associated with the more readily available fractions (exchangeable and specifically adsorbed) than is observed for Pu, Am or Cs. The organic phase nevertheless remains significant in Np retention and binding.