BEAGL-01, a computer code for calculating rapid LWR core transients

BEAGL-01 (Brookhaven's and EPRI's Adaptation of the TWIGL code) is a computer program for calculating the conditions in a light water reactor (LWR) core at steady state and during transients. It solves the finite-difference neutron kinetics equations on an r,z (radial, axial) mesh, the thermal-hydraulic equations for the coolant in multiple parallel, i.e., one-dimensional, channels and the one-dimensional radial fuel rod heat conduction equations for pellet, gap and clad. The analyst provides time dependent boundary conditions and/or specifications for control rod movement in order to perturb the system from an initial steady state. The boundary conditions are the inlet flow rate and temperature and a single system pressure. The analyst also supplies a normalized inlet flow distribution across the core which does not vary with time. Control rod movement includes the center rod by itself, all banks of control rods, or some combination of these. The objective of this summary is to give capabilities and limitations.