The in situ Full-scale Engineered Barriers Experiment or Febex was a full-scale test reproducing the near field of a nuclear waste repository. It was performed in a gallery excavated in granite at the Grimsel Test Site in Switzerland, with a heater whose surface temperature was set to 100°C, simulating the waste canister and a bentonite barrier composed of highly compacted blocks. The test was completely dismantled after 18 years of operation. Numerous samples of bentonite were taken for the on-site determination of dry density and water content. The on-site measurements showed that the physical state of the barrier was very much affected by the processes to which it had been subjected, namely, hydration with the granite groundwater and/or thermal gradient. Although the degree of saturation of the bentonite was overall quite high, there were important water content and dry density gradients everywhere in the barrier, but the gradients were steeper around the heater. These gradients did not impair the performance of the barrier, but imply that the barrier can be irreversibly inhomogeneous.

中文翻译：

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18年后的原位Febex测试（瑞士GTS）的状态：一种不均匀的膨润土屏障

原位全面工程化障碍实验或Febex是一项全面测试，可再现核废料储存库的近场。它是在瑞士格里姆瑟尔试验场的花岗岩开挖的画廊中进行的，加热器的表面温度设置为100°C，模拟了废物罐和由高度压实的砖块组成的膨润土屏障。经过18年的运行，该测试已完全拆除。大量膨润土样品被用于现场测定干密度和水含量。现场测量表明，屏障的物理状态受其所经历的过程的影响很大，即花岗岩水化和/或热梯度水化。尽管膨润土的饱和度总体上很高，屏障中到处都有重要的水分含量和干密度梯度，但在加热器周围梯度较陡。这些梯度不会削弱屏障的性能，但是暗示屏障可能是不可逆的不均匀的。