[en] Nuclear Power Plant (NPP) is one of the nuclear energy utilization for electrical energy needs. The consequences on nuclear energy utilization such as NPP is the radiological impact resulting from the radioactive material releases from the plant as the fission product of uranium fuel. In normal operation and in accident conditions, there are processes of radioactive material or fission product release from the fuel element and other components the can reach the containment environment and it can release to environment of the plant. But this release is limited by implementing the safety requirement to the design in order to get the very low consequence with the environment radiation doses is still under the permissible value. The reactor operation conditions, the possibility accident occurrence that produce the heating of the fuel cladding, accident analysis for safety evaluation using deterministic and probabilistic methods are described. For conducting the environment radiological consequences, the important thing as the input data is the source term data resulting from source term analysis, mainly are the release activity and release characteristic. The process and mechanism of the release from fuel element is also described. In the frame of safety evaluation of the NPP, the results of the source term analysis and radiological consequence analysis are to be the measure of the environment radiological consequences can still limited and still in the save condition, and all the value of the calculated parameters are below the permissible value based on standard and code