Which types of nuclear reactors are refueled online?

The ability to refuel online is an important aspect of certain nuclear reactor designs. CANDU (Canada Deuterium Uranium) and MAGNOX reactors are specifically engineered to allow for online refueling, which means they can be refueled without shutting down the reactor. This capability is a significant operational advantage, as it allows for continuous power generation and improved overall efficiency.

CANDU reactors utilize a heavy water moderator and are designed with refueling machine systems that facilitate the addition of fresh fuel while maintaining reactor operation. Similarly, MAGNOX reactors utilize natural uranium and have a design that supports online refueling through a simpler refueling strategy, which also avoids the need for costly and time-consuming shutdowns.

In contrast, other reactor types like Pressurized Water Reactors and Boiling Water Reactors typically require a planned outage for refueling, as their designs do not accommodate refueling while the reactor is operating. Fast-Breeder Reactors, while innovative, often face similar logistical challenges as other light-water reactors in terms of refueling processes. Advanced Gas-cooled Reactors also generally rely on shut-down refueling approaches, as their design and operational protocols are not aligned with online refueling capabilities.

Therefore, CANDU and MAG