الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Nowadays, many efforts have been made to improve the efficiency of nuclear power plants. One of which is use of the dual cooled annular fuel which is an internally and externally cooled annular fuel with many advantages in heat transfer characteristics. In this thesis, we examined the possibility of using uranium nitride (UN) annular fuel instead of (UO2) solid fuel in the core of an AP-1000 reactor.We investigated the internally and externally cooled annular fuel for the typical operating AP-1000 reactor core,using MCNPX 2.7.0 code. We also considered some important thermal hydraulic parameters such as the pressure DROP on the core, the surface heat flux, the fuel and the coolant temperatures and the departure from nucleate boiling ratio, using RELAP5 code. We used uranium nitride (UN) instead of uranium dioxide (UO2) because of the higher theoretical density of (UN). The burnup capability of the solid fuel was about the same as the annular design because of the same enrichment. However, the nuclear annular fuel showed many advantages such as the ability to increase the thermal power of nuclear plants. Also, the annular fuel rods had a sufficient margin available for MDNBR in both the inner and the outer surfaces relative to the cylindrical solid fuel. This margin accommodated a 125% power-uprate. Finally, we proposed a 12 x 12 assembly based on our neutronics and thermal hydraulic calculations.