Validation and Benchmarking of the HELIOSRAMONA Model of Dodewaard

Abstract

The Interfaculty Reactor Institute (IRI) has developed a coupled thermal hydraulic and neutronic model of the natural circulation cooled Dodewaard reactor based upon the codes HELIOS and RAMONA. The technique used to validate the HELIOS cross section model consisted of a "blind test" to compare the results of static and transient RAMONA coupled thermal hydraulic and neutronic calculations performed for operating cycle 18 using the neutron cross section libraries prepared by IRI using HELIOS and by Scandpower using the RECORD code. The normalized axial power profile obtained with the HELIOS cross sections shows superior agreement with the measured TIP data relative to the results obtained using the RECORD cross sections, particularly at the core inlet and outlet. RAMONA static calculations were performed to determine the xenon, control rod, void, and Doppler reactivity worths predicted with each cross section set, and acceptable agreement was obtained for each case. Transient RAMONA calculations consisting of sinusoidal control rod and pressure perturbations were also performed with each cross section library, and again excellent agreement was obtained. Thus, the Dodewaard model can be considered validated. IRI is now benchmarking the HELIOS/RAMONA model against the measured conditions for Dodewaard operating cycle 26. This particular set of measurements was selected because it contains a wide range of operating conditions including nominal, low pressure, and low flow situations, and one case that was not stable. Thus, these data should identify the range of applicability of the model.