Nuclear's best kept secret

Part 2: The Technology Behind the Success

CANDU reactors aren’t just high-performing — they’re also uniquely designed to be versatile and efficient. Here’s what makes them stand out technologically.

1. Heavy Water Moderation

CANDU reactors use heavy water (deuterium oxide) as both a moderator and a coolant. Unlike light water reactors (LWRs), which require enriched uranium fuel, heavy water's superior neutron economy enables CANDU reactors to use natural uranium. This reduces fuel costs and dependence on enrichment infrastructure. Additionally, heavy water’s excellent thermal properties enhance reactor safety and efficiency by maintaining stable operating conditions even under variable loads. The ability to efficiently use natural uranium makes CANDU reactors both cost-effective and fuel-flexible.

2. Online Refueling

Unlike many other reactor designs, CANDU reactors can be refueled while in operation. This unique feature enhances their capacity factor and operational efficiency. It also provides greater flexibility to adapt to varying electricity demand.

3. Fuel Versatility

CANDU reactors are not limited to using natural uranium. They can also operate with recycled uranium, thorium, and even spent fuel from other reactor types. For example, the Cernavod? Nuclear Power Plant in Romania has successfully utilized recycled uranium, and experimental studies in India have demonstrated the viability of thorium in CANDU reactors. These cases highlight the technology's adaptability and potential to maximize fuel resource efficiency globally.

4. Robust Safety Features

Safety has always been a priority for CANDU designs. Their unique design includes multiple passive safety systems, including gravity-fed cooling mechanisms, making them highly resilient in case of emergencies.

5. Scalability and Adaptability

CANDU technology has proven scalable, from smaller reactors to large-scale units, and adaptable to various market needs. Whether it’s serving a large grid or a smaller regional network, CANDU reactors deliver consistent performance.