One of the key issues of research and development at GRS is to provide reliable methods and procedures for the safety-related assessment of light water reactors. The work comprises the development and validation of computer codes for the analytical simulation of incidents and accidents concerning the reactor core, the reactor coolant system and the containment as well as for probabilistic safety analyses that are carried out for the integral determination of the risk of nuclear power plants. The monitoring and evaluation of national and international reactor safety experiments is an essential part of these activities, thereby forming part of the international reactor safety research network. The results obtained in this context provide the scientific basis for the further development and application of analytical simulation models. Our codes:

•    ASTEC developed in co-operation with IRSN – integral code for determination of the source term during core meltdown fort he primary circuit and containment of LWR
•    ATHLET thermohydraulic safety analyses for the primary circuit of  LWR
•    ATHLET-CD analyses of accidents with core meltdown and fission product release for LWR
•    ATLAS analyses simulator for interactive handling and visualization of several computer codes
•    COCOSYS analyses of severe incidents in the containment of LWR
•    DORT/TORT solution of timedependant neutron transport equations for 2D/3D- transients analyses
•    QUABOX/CUBBOX 3-D-neutron-kinetic core model
•    SUSA uncertainty and sensitivity analyses
•    TESPA-ROD core rod code for design basis accidents

The figure below illustrates the interaction of different code systems.