Due to technical reasons Instrumentation and Control (I&C) systems have to be replaced to an increasing degree by computer-based I&C systems. For the development and implementation of safety-related computer-based I&C systems Integrated Tool Environments (ITE) are employed. Most of these ITE were not conceived originally for the implementation of nuclear specific applications. The quality of the ITE may be proven and certified for industrial applications but the qualification for the nuclear application has to be demonstrated. This paper proposes an assessment method and activities for the efficient and transparent qualification of ITE for the use in safety-related applications according to nuclear standards and state of the art. The assessment aims at a pre-qualification of ITE detached as far as possible from the safety functions implemented by them. The results of this pre-qualification shall assist and facilitate the safety analysis of the application software.