The aim of this study is to analyze risk model and software requirements for decision support system based on risk management (DSS-RM) as applied to power engineering installations. Power engineering safety substantially affects national security. So the decision support system is intended for the improvement of risk management by more effective risk and damage assessment, ranking strategies, proposing countermeasures on mitigating consequences. The main goal of DSS-RM is to reach lowest acceptable risk levels. However, the delicate problem is how to permit the responsible person to make voluntary decisions on the base of his own expert judgements or because of uncontrolled or unforeseen circumstances. DSS-RM have to take into account of this “human factor” uncertainty and software requirements must be developed very carefully in close cooperation with end user.