3. NATURE OF PHYSICAL PROBLEM SOLVED
SCORCH-B2 is a simulation code of reactor core heatup during a LOCA of BWR's. The program analyzes transient heat transmission on a horizontal plane of a fuel assembly and evaluates the peak cladding temperature and the maximum oxide thickness, both of which determine the soundness of the core during the accident. Fuel rods are arbitrarily classified into a smaller number of groups and each fuel rod is divided into several annuli.
Heat conduction within fuel rods, heat convection from rods to coolant and radiation among rods and the channel box are calculated for each time step.