FEMSYN - a code system to solve multigroup diffusion theory equations using a variety of solution techniques. Part 3 : FINERC - the finite element module

For the solution of multigroup diffusion theory equations by finite element method (FEM) a code called FINERC has been developed. One can solve 1-D, 2-D and 3-D problems in Cartesian geometry and 1-D (r-) and 2-D (r-z) problems in cylindrical geometry. Radially one can use arbitrary combination of rectangular and trangular elements in x-y geometry. For 3-D problems the element shapes are with base orthogonal to the axial direction. Interpolation functions are Lagrange polynomials. The polynomial order of the interpolation functions in radial and axial directions can be any combination of linear to cubic in either of them. Element-node numbering and the topological information of their inter-connectivity is automatically generated by the program. Zero flux current and gamma type boundary conditions can be applied on any boundary surface. Direct inversion methods like Choleski decomposition, diagonal band elemination are used for 1-D and 2-D problems. 3-D problems are solved plane by plane. Two parameter Chebyschev acceleration for fission source is used. FINERC can be used to provide benchmark solutions for problems involving complicated geometry. (author)