Many nuclear power plants requires improvement and modification of their radwaste treatment system. These needs are divided into development of new technology and development of operation. Concerned with the second need, we presented a mathmatical procedure through which a radwaste treatment plan can be derived in an interative and interactive manner. The ultimative objective of the system is to minimize the release of radioactive material into the enviornment. In planning the practical operation of the system, however, the operating cost, process economics and technical flexibility must be considered, also. For dealing with these multiple criteria decision making (MCDM) problems, we used RESTEM(Revised Step Method) which is a kind of multiobjective linear programming (MOLP). As a result of optimization, we derived the optimal state of the system operation. In addition, we investigated the effect of variation of the operating parameters on the optimization. We showed that these results can be applied into planning of the practical plant operation if some problems are solved.