The applications of nuclear technology in reactor siting with reference to earthquake prediction and fault exploration are discussed. The technique first used thin thermoluminescent dosimeters to monitor alpha particles from soil radon emanation; these dosimeters were later replaced by cellulose nitrate films and a self-fabricated spark counter. Data from a 2-yr observation of soil radon emanation correlated with earthquakes are presented graphically. Radon peaks appeared 5 to 20 days before earthquakes. A similar technique was also applied in fault exploration. The higher radon peaks appear at the location of the fault. This simple and inexpensive technique is particularly well-suited to nuclear reactor siting since the area of interest at the site is quite limited. The extension of this technique to the public communication program for a nuclear facility is also suggested.