The development of the wireless transmission monitoring in the geological disposal repository, the underground laboratories, the test facilities and the demonstration area, will present an opportunity to provide greater flexibility and robustness to the confirmation of the barrier performance and therefore safety of repository [1]. So as to realize the wireless transmission monitoring especially in the betonite barrier, RWMC has been researching and developing the wireless data transmission system which uses the very low frequency (VLF: around 1 kHz) electromagnetic wave. In this system, transmitting and receiving is conducted through loop coil antennas. The overall transmission system is digitized and maximum 19 sensors can be connected to one transmitter. Transmission distance can be selected from several meters to several hundred meters.This paper firstly presents the behavior of VLF electromagnetic wave propagation in the rock mass and the underground facility revealed by the in-situ transmission experiment and the analytical method evaluating the behavior of the VLF electromagnetic field in various environments. Development results of the transmitting antenna and the improvement of the transmission performance are secondly shown. The technical feasibility and the future R&D plan of the wireless monitoring in the repository are also explained.

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is recommended as an important philosophy for the long lived radioactive waste disposal by the government. ANDRA has been establishing the concept of reversible repository and its step-wise management. Monitoring is considered to play an important role so as to realize the step-wise management. However, it never be allowed that the monitoring system deteriorate the performance of the barrier of the repository. In this report, the concept of the wireless monitoring system, which contributes to monitoring in the reversible repository without any disturbance of the barrier, is presented. Its technical feasibility is also described on the basis of the experimental study.

土木学会論文集E2（材料・コンクリート構造）, Vol. 72, No. 3, 234-248, 2016. 土木学会論文集E2（材料・コンクリート構造）, Vol. 72, No. 3, 234-248, 2016.