Abstract Workers in the Juzbado plant of ENUSA in Spain are exposed to intakes of low enriched uranium during the fabrication of nuclear fuel elements for Nuclear Power Plants. CIEMAT started in 2014 an individual monitoring program for ENUSA workers consisting in routine bioassay measurements of uranium in urine by alpha spectrometry and a methodology of dose assessment based on ICRP Publications 78/68, ISO 27048 standard and IDEAS Guidelines V2. The individual monitoring program is complemented with workplace monitoring using Static Air Samplers (SAS) at the Juzbado facility. Results of routine monitoring data of 24 h-urine samples of Juzbado workforce confirmed low level of chronic intakes of uranium oxides in the plant, combined with acute intakes associated to incidents. IMBA software allows the dose assessments in complex intake regimes of occupational inhalation of Type S uranium compounds. Uncertainties of monitoring data were evaluated using the Scattering Factor approach (ISO 27048) for the intake calculation in the defined internal exposure scenario. A total of 200 workers at risk of internal exposures in the Juzbado facility were included in routine, special, confirmatory or task-related monitoring programs established by CIEMAT in agreement with ENUSA. Annual chronic intakes were assessed for 106 workers with monitoring results above the Minimum Detectable Activity (MDA = 0.50 mBq.sample−1 of 234U, 238U and 235U). Committed Effective Doses E(50) > 1 mSv/year were initially detected in 50% of these cases. Maximum annual intakes correspond to few cases of long term exposed workers with E(50) around 5 mSv/year. The preliminary study of the impact on the dose assessment using the new uranium model according to ICRP Publication 137 is presented here, showing a reduction of E(50) around a factor of 4 for workers exposed to uranium oxides re-defined as Type M/S materials (more soluble compounds, higher urinary excretion, lower dose coefficients than Type S uranium materials defined by ICRP Publications 78/68).

中文翻译：

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西班牙核燃料制造过程中暴露的铀工人的内部剂量测定

摘要 西班牙 ENUSA 的 Juzbado 工厂的工人在为核电站制造核燃料元件的过程中接触到摄入的低浓铀。CIEMAT 于 2014 年启动了一项针对 ENUSA 工作人员的个人监测计划，包括通过 α 光谱法对尿液中的铀进行常规生物测定测量以及基于 ICRP 出版物 78/68、ISO 27048 标准和 IDEAS 指南 V2 的剂量评估方法。Juzbado 工厂使用静态空气采样器 (SAS) 对个人监测计划进行了补充。Juzbado 劳动力 24 小时尿液样本的常规监测数据结果证实，工厂中氧化铀的慢性摄入量较低，并且与事故相关的急性摄入量较低。IMBA 软件允许在职业吸入 S 型铀化合物的复杂摄入方案中进行剂量评估。使用散射因子方法 (ISO 27048) 评估了监测数据的不确定性，以在定义的内部暴露场景中计算摄入量。共有 200 名在 Juzbado 设施中面临内部暴露风险的工人被纳入 CIEMAT 与 ENUSA 协议制定的常规、特殊、确认或与任务相关的监测计划。对 106 名工人的年度慢性摄入进行了评估，监测结果高于最低可检测活动（MDA = 0.50 mBq.sample−1 of 234U、238U 和 235U）。最初在这些病例中的 50% 中检测到承诺有效剂量 E(50) > 1 毫希沃特/年。每年最大摄入量对应于 E(50) 约为 5 毫希沃特/年的长期接触工人的少数情况。此处介绍了根据 ICRP 第 137 号出版物使用新铀模型对剂量评估影响的初步研究，表明暴露于重新定义为 M/ S 材料（与 ICRP 出版物 78/68 定义的 S 型铀材料相比，更易溶解的化合物、更高的尿排泄量、更低的剂量系数）。