Scram cause evaluation of unbalanced load channel - reactor protection system at operation of the RSG-GAS reactor

Safety in the operation of the Reactor Protection System is implemented by the scram action. However scram which often happened is the failure of the operation and poses other risks. The purpose of this study is to determine the trigger and the reasons for scram with analytic descriptive method through interviews, observation and document review, combined with the preparation of fault tree analysis. The analytic descriptive results show that trigger of scram are, the neutron flux density is too high, too fast operation period, unbalanced load, and the occurrence of positive transient reactivity. While the basic causes of the scram incident on channel unbalanced load, consisting of the failure of instrumentation systems,neutron flux uneven conditions, the fall of one of control rods, the emptying of the beam tube, interference handling and loading of samples irradiated, and the local hot channel at the fuel elements. Therefore function of scram as anticipation of the accident is also the feedback of operating experience for updating on safety assessment so that failure of the operation can be minimized. (author)