ABSTRACT

A safety assessment was performed on the second-phase disposal facility of the Gyeongju low – and intermediate-level radioactive waste repository using the RESRAD-OFFSITE code. On the basis of the acceptance criteria of the repository, 13 radionuclides and gross alpha were selected as the radionuclides to be evaluated. In addition, the thermodynamic database of Japan Atomic Energy Agency and natural groundwater data that reflect the operational condition of the disposal facility were applied to derive the solubility by using the PHREEQC computational code. The distribution coefficient was derived for the component of disposal facility based on the sorption database of Japan Atomic Energy Agency. In addition to the solubility and distribution coefficient for various radionuclides, the data of the disposal facility and repository site were analyzed and applied to the RESRAD-OFFSITE code for the safety assessment modeling. The result of the safety assessment calculation revealed the exposure dose corresponding to 3.8% of the exposure dose limit (0.1 mSv/yr). Moreover, additional sensitivity analysis for the exposure dose was conducted by varying the geochemical parameters. Although the exposure dose changed as the geochemical parameters were varied, the result of the sensitivity analysis confirmed that the exposure dose limit was still satisfied.

摘要

使用 RESRAD-OFFSITE 代码对庆州中低放废物处置库二期处置设施进行了安全评估。根据处置库的验收标准，选择了13种放射性核素和总α作为待评价的放射性核素。此外，利用日本原子能厅热力学数据库和反映处置设施运行状况的天然地下水数据，利用PHREEQC计算代码推导出溶解度。分配系数是根据日本原子能厅的吸附数据库为处置设施部件推导出来的。除了各种放射性核素的溶解度和分布系数，对处置设施和处置库场址的数据进行了分析，并将其应用于用于安全评估建模的 RESRAD-OFFSITE 代码。安全评估计算的结果显示，暴露剂量相当于暴露剂量限值 (0.1 mSv/yr) 的 3.8%。此外，通过改变地球化学参数对暴露剂量进行了额外的敏感性分析。虽然暴露剂量随着地球化学参数的变化而变化，但敏感性分析的结果证实仍然满足暴露剂量限值。通过改变地球化学参数对照射剂量进行了额外的敏感性分析。虽然暴露剂量随着地球化学参数的变化而变化，但敏感性分析的结果证实仍然满足暴露剂量限值。通过改变地球化学参数对照射剂量进行了额外的敏感性分析。虽然暴露剂量随着地球化学参数的变化而变化，但敏感性分析的结果证实仍然满足暴露剂量限值。