Etude numerique du transitoire accidentel d’une chaudiere industrielle par le code relap5/MOD3.2

Abstract

The main objective of this work involves the simulation of the overall behavior of an industrial radiant steam boiler ABB ALSTOM (GNL Complex, SKIKDA) at the accidental transient using the RELAP5/MOD3.2 computer code. The RELAP5/Mod3.2 model qualification results at the steady-state are in good agreement with the steam boiler experimental data. Two types of transients are treated as part of this work since they are the most hazardous for this kind of facilities. They concern the loss of feedwater supply to the boiler (feedwater pump costs-down) and the leakage from the boiler when some pipes on the hot leg side are broken. This study analyzed the thermal-hydraulic phenomena that may occur in the steam boiler steady-state and transient operation mode. For this, a detailed model of the all system is built from a strong qualification. This work shows the RELAP5/MOD3.2 large capabilities to simulate all the phenomena occurring in the steam boiler during the transients. The results of this work may be of great importance for the steam boiler owner since the developed model could be used to help in performing some changes in design or operating procedures and to improve the response and reliability of control and protection systems during the accidentals transients.