Embalse Steam Generator Level Control

Abstract

This paper introduces the unique combination of new Steam Generator (SG) cartridges and the existing Embalse drums for the purpose of SG replacement. The new design presents clear advantages for extraction and re-introduction of new SGs but it also presents several design challenges. The issues are also augmented by the intent to increase the current 2015 MWth thermal power output to 2064 MWth . To achieve this, four larger SG cartridges will be installed to make the system power output nearly identical to other CANDU® 6 stations. Moreover, the feedwater system will be updated to supply the required water at the desired temperature to the secondary side of the SGs to maintain their desired levels during various modes of operation. This paper also describes the challenges with respect to the Embalse SG Level Control (SGLC) to satisfy the operation and safety requirements. The new SGLC logic is designed using the Candu Energy sophisticated analytical simulator, C6SIM and the Canadian Algorithm for THErmohydraulic Network Analysis (CATHENA). The robustness and excellent performance of the new controller has been achieved at various power levels when reactor is operating at normal power and also following the events that requires sudden or gradual power reduction by the reactor control system.