Flow-induced vibration (FIV) at the spacer grid in the fuel assembly of a Light Water Reactor (LWR) is the leading cause of fuel failure. This project aims to produce a simulation benchmark on the experimental campaign at MACE on axial FIV of a cantilever beam in an annular tube, that mimics the configuration and environment of a typical LWR. The nuclear fuel rod, which consists of fuel pellets filled in Zirconium alloy cladding is modelled in the experiment as a steel rod filled with lead shots that closely approximates the filling density of the fuel pellet. To reduce the complexity and increase the efficiency of the simulation, further simplification is applied by on the geometry and assuming the solid domain as a single material instead of multiple materials. The first mode of frequency of the rod vibrating in quiescent water, which had been validated via the Euler-Bernoulli beam theory against experimental measurements, was used to design the single-material solid domain. Two models were proposed, firstly a solid rod with lower density and stiffness (SLE), and secondly an empty cladding with high density and low stiffness (EHD). Both solid and fluid domains were discretised using the cell-centred finite volume (FV) method and coupled with strong two-way fluid-structure interaction (FSI). Results on the frequency of vibration in quiescent water and in axial flow showed good agreement with experimental measurement, and the computational efficiency is analyzed for different rod models and changes in parameters of the solid domains.
In the beginning of the 21st century, several research institutions and also private companies had proposed various design of thorium-based nuclear reactor, ranging from solid fuel to molten fuel, fast and thermal neutron spectrum and also various path of waste management. This paper studies 10 of the proposed reactor designs by 10 different organizations, three key aspects analysed quantitatively namely price per kilowatt, safety features and spent fuel managements. Corresponding factors contributing to the key aspects mentioned above were gathered, weighted based on evidence available and analysed using decision matrix. Based on the information collected, preliminary ranking were constructed based on trends between various factors.
Gamma and neutron irradiation effect on sand and activated carbon were studied in this paper intensively and, were found from various studies to have strong correlation between neutron fluence or gamma energy on physical and mechanical damage of materials. Sand and activated carbon were irradiated with neutron at Reactor TRIGA PUSPATI (RTP) and gamma at Sinagamma Malaysia Nuclear Agency (Nuklear Malaysia). Morphological analysis was carried out on the irradiated elements using the SEM, XRD and SAXS which showed changes on the microstructure of irradiated samples. Irradiation of activated carbon showed increase in the numbers of pores while change of textural profile of the surface take place at gamma irradiated sand. XRD pattern graph did not indicate any changes, however the specific surface area for both irradiation materials decreased.
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