TRAC analysis support for the 2D/3D program

The 2D/3D Program is a multinational (Germany, Japan, and the United States) experimental and analytical nuclear reactor safety research program having as its main purpose the investigation of multidimensional thermal-hydraulic behavior during the refill and reflood phases of loss-of-coolant accidents (LOCAs) in pressurized water reactors (PWRs). The German contribution to the program is the planned Upper Plenum Test Facility (UPTF), a full-scale facility with vessel, four loops, and steam-water core simulator. The Japanese are presently operating two large-scale test facilities as part of this program: the Cylindrical Core Test Facility (CCTF) and the Slab Core Test Facility (SCTF). The Los Alamos National Laboratory is the prime contractor to the NRC in the latter activity. The main analytical tool in this program is the Transient Reactor Analysis Code (TRAC), a best-estimate, multidimensional, non-equilibrium, thermal-hydraulics computer code developed for the NRC at Los Alamos. Through code predictions of experimental results and calculations of PWR transients, TRAC provides the analytic coupling between the facilities and is extending the results to predicting actual PWR behavior