[en] 1 - Description of program or function: COMTA-IIM is a program for integrated fuel performance analysis for free standing cladding with ceramic fuel. The program accepts design, manufacturing and operating parameters as input and gives the state of cladding at end of life. In the package supplied, more emphasis is placed on mechanical analysis and the associated convergence requirements. The package essentially performs 1-dimensional analysis of a thin slice giving triaxial stress and strain values for elastic, thermal and creep behaviour of the cladding at each of the points in the supplied power history (Time Vs. heat flux). 2 - Method of solution: COMTA can be divided into two parts. viz. thermal and mechanical. The segment performing the thermal analysis calculates radial temperature distribution across pellet and clad. This also establishes pellet-cladding mechanical interaction which is fed to the mechanical analysis segment. For mechanical analysis, a thin slice of cladding is analysed as a plain strain problem. Non-linearity arises because of the presence of neutron induced creep and plasticity in the cladding. Convergence problems arising in performing time integration are tackled by having an elaborate subroutine for time step selection and having an alternate convergence scheme. The program has the Newton-Raphson and Variable Metric methods as two different types of non-linear equation solution algorithms. 3 - Restrictions on the complexity of the problem: Currently the program cannot take more than five radial nodes across the clad. This can easily be increased by changing a corresponding parameter in the program