Development of neutral particle transport code ATES3 and further studies on Transport Synthetic Acceleration

This paper presents a new 3-D multigroup neutron transport code 'ATES3' developed in BARC, India for problems in Cartesian geometry. It is based on discrete Ordinates (Sn) method with finite difference scheme for spatial variable. It solves external source as well as K-eigenvalue problems. An important feature of this code is the use of schemes based on Krylov subspace methods for inner and outer iterations namely Transport Synthetic Acceleration (TSA) and Orthomin(1). Analysis of many test cases by code ATES3 is described. Some detailed studies on the utility of the TSA scheme are also presented for situations not reported earlier such as anisotropic scattering and 2-D curvilinear geometry. (authors)