24-Month long cycle fuel management research based on accident tolerant fuel

As the installed nuclear power plants steadily increase in China, the demand for 24-month long cycle fuel management is gradually increasing as well. 18-month refueling strategy is mainly applied in PWRs currently, and the fuel enrichment and burnup have already reached the limits. By utilizing the accident tolerant fuel (ATF), fuel performance can support higher rod burnup and fuel enrichment, a more economical 24 month refueling cycle strategy can be achieved. In this paper, with the enrichment and burnup limits improved based on ATF fuel, 24-month fuel management strategies are designed. The core design meets the requirements of safety related acceptance criteria. Fuel rod performance analysis results indicate that, to achieve a higher burnup, it is necessary to introduce coated cladding and large grain pellet to mitigate cladding corrosion and fission gas release. This study provides technical support for the longer cycle operation of passive nuclear power plants and points out the direction for improving fuel enrichment and rod burnup limits.