Wang Guoxin - Seismological Bureau of Liaoning Province, No.۴۴ Huanghe north street Shenyang ۱۱۰۰۳۱, P.R.China
Chen Shenlai - Design and Research Department, Shengyang Municipal Urban and Rural Construction Committee ۱۱۰۰۰۲ Shenyang, Liaoning Province, P.R.China
Hui Rihong - Seismological Bureau of Liaoning Province, No.۴۴ Huanghe north street Shenyang ۱۱۰۰۳۱, P.R.China

In order to evaluate the regional crust stability of the sites for the Liaoning Nuclear Power Plant, six quantified environmental factors, viz., the seismicity, active faults, deep faults, gradient of crustal thickness, gradient of crustal deformation and fault angle, are selected as the criteria for evaluation and the stability of ۴۸ units divided in the studied region are evaluated by use of fuzzy mathematics, grey theory and pattern recognition. The result shows that there are ۱۶ stable units, ۲۱ substable units, ۹ unstable units, and ۲ active units in that region. The two optional sites are located in stable and substabie units, respectively, both suitable for the construction of the nuclear power plant in plan