HTGR Knowledge Base

Conference Article: Transient Behaviour and Control of the ACACIA Plant

J.F. Kikstra, A.H.M. Verkooijen, A.I. van Heek NRG, P.O. Box 25, NL-1755 ZG Petten, The Netherlands Delft University of Technology, Faculty of Mechanical Engineering, Mekelweg 2, NL-2628 CD Delft, The Netherlands

Abstract

This article deals with dynamic modelling and control of the ACACIA plant. A one-dimensional flow model describing the helium flow and the two-phase water flow is used through the whole plant, with different source terms in different pieces of equipment. A stage-by-stage model is produced for the radial compressor and axial turbine. Other models include the recuperator, water/helium heat exchangers, a natural convection evaporator, valves, etc. The models have been checked by comparison of the transient behaviour with several other models, e.g. produced in RELAP. The dynamic behaviour of this plant is analysed and a control structure is designed. First the requirements and options for a control system design are investigated. A number of possible control valve positions in the flowsheet are tested with transients in order to make an argued choice. The model is subsequently used to determine the optimal working conditions for different heat and power demands, these are used as setpoints for the control system. Then the interaction between manipulated and controlled variables is mapped and based on this information a choice for coupling them in decentralised feedback control loops is made. This control structure is then tuned and tested. It can be concluded that both heat and power demand can be followed with acceptable performance over a wide range.

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key words: Gas Cooled Reactor, Nuclear Technology
Reference:
IAEA Technical Committee Meeting on “Gas Turbine Power Conversion Systems for Modular HTGRs”, held from 14-16 November 2000 in Palo Alto, California
International Atomic Energy Agency, Vienna (Austria). Technical Working Group on Gas-Cooled Reactors
IAEA-TECDOC--1238, pp:87-101