(GRS-39) GARLIC-B – A Digital Code for Real-Time Calculation of the Transient Behaviour of Nodal and Global Core and Plant Parameters of BWR Nuclear Power Plants - Program Description

Y. Ercan, A. Höld, O. Lupas

A program description of the code GARLIC-B is given. The code is based on a nonlinear transient model for BWR nuclear powerplants which consist of a 3D-core, a top plenum, steam removal and feed water systems and a downcomer with main coolant recirculation pumps. The core is subdivided into a number of superboxes and flow channels with different coolant mass flowrates. Subcooled boiling within these channels has an important reactivity feed back effect and has to be taken also into account. The code computes the local and global core and plant transient situation as dependent on both the inherent core dynamics and external control actions, i. e., disturbances such as motions of control rod banks, changes of mass flow rates of coolant, feed water and steam outlet. The case of a pressure-controlled reactor operation is also considered.