Core design study for power uprating of integral primary system PWR

Core design study for power uprating of integral primary system PWR has been performed. The selected reference core design is a four-year straight burn option of the International Reactor Innovative and Secure (IRIS). The objective of this study is to evaluate the possibility of increasing thermal power of the IRIS reactor by 20%, for a better economic performance. This study includes core neutronic and thermal hydraulic aspects. The power uprate is achieved by minimizing core radial power peaking, and by increasing fuel enrichment and coolant mass flow rate. Parametric calculations have been carried out to optimize the power-uprated core design, with the objective of obtaining relatively low core power peaking and similar initial reactivity with that of the reference core. The optimization is achieved by means of enrichment zoning and application of burnable poison, with different configuration from that of the reference core. The performance of power-uprated core is compared with the reference core. The calculation results show that the proposed core-uprated design with thermal power of 1200 MWt shows preferable characteristics, such as low power peaking of around 1.43, negative reactivity coefficients, and relatively high MDNBR of 3.454.