Fault Activity in Clay Rock Site Candidate of High Level Radioactive Waste Repository, Tamusu, Inner Mongolia

Tamusu area in Inner Mongolia is one of the favorable site candidates for high level radioactive waste (HLW) repository, which requires a stable regional tectonic environment. Field investigation, mossbauer spectroscopy, major elements, carbon and oxygen isotope and quartz micro morphology of fault gouge and host rock of three faults in the site candidate were conducted. The results show that the F2 and F7 faults on the north and south sides of the site candidate are in a relatively stable state with good sealing and weak activity. Part of the F4 fault is located in the site candidate, and the deportment of a small amount of pyrite in the fault zone and the difference of carbon and oxygen isotopes indicate that it may have experienced material exchange with the deep zone. Attention should be paid to induced earthquake risk.