基于双重回填屏障结构的废物包容性研究

Closure to Radioactive Waste Based on Double Barrier Backfill Stucture

针对某放射性废物包装容器材料为碳钢的状况,为强化废物处置后工程屏障对废物的长期包容性,提出了混凝土与膨润土的双层回填屏障结构模式。实验研究表明,混凝土环境中,10 mm壁厚碳钢容器基体的寿命不低于2 000 a;混凝土水化学环境中99.9%的Pu以难迁移的Ⅳ价态Pu(OH)5-形式存在,有利于减缓和阻滞核素迁移;膨润土的低渗透性及对废物中Pu的强吸附性,可以很好地阻滞核素向环境释放迁移。

Considering the material of certain radioactive waste packaging container as carbon steel, for strengthening longterm closure of the engineering barrier to the waste after disposal, we put forward a double barrier backfill structure model composed of concrete and bentonite. The experimental results show that, in the concrete environment, the life of the 10 mm wall thickness carbon steel container body is not lower than 2 000 a; In the concrete hydrochemical environment, 99.9% of the Pu is in the chemical species of Pu( Ⅳ)(OH)5-, which helps to reduce and retard the radionuclide migration; The low permeability of bentonite and its strong adsorption to Pu, can effectively retard the nuclide released to environment.