Nuclear Power Plant Safety Systems

Summary

This video explains the safety systems in Canada's nuclear power plants, focusing on the CANDU reactor design. It covers key functions such as reactor control, fuel cooling, and radiation containment. The reactor uses multiple, independent safety systems that ensure rapid shutdown, continuous fuel cooling, and robust radiation protection. Emergency power sources and backup systems are in place to ensure safe operations. The Canadian Nuclear Safety Commission oversees and regulates these plants, ensuring strict adherence to safety standards through inspections and continuous improvement. These measures contribute to making Canada's nuclear power plants among the safest in the world.

Takeaways

• 😀 Canada is home to nuclear power plants located in Ontario, Quebec, and New Brunswick, operated under strict safety rules established by the Canadian Nuclear Safety Commission (CNSC).
• 😀 The CANDU reactor design is used across all Canadian nuclear plants, generating electricity by splitting atoms of natural uranium to create heat, which powers turbines and generators.
• 😀 After being used in the reactor, nuclear fuel is securely stored in a pool for 6 to 10 years, where it is cooled by water and shielded from radiation.
• 😀 Canadian nuclear power plants have multiple safety systems in place to control the reactor, cool the fuel, and contain radiation, all regularly maintained and upgraded as needed.
• 😀 Reactor power levels are controlled by adjuster rods and varying water levels, and CANDU reactors can safely and automatically shut down within seconds using two independent systems.
• 😀 The two shutdown systems include: 1) automatic dropping of rods to stop the nuclear reaction, and 2) injecting a liquid to immediately halt the reaction. Both systems function without power or operator intervention.
• 😀 Fuel cooling is achieved by three systems: the heat transport system, steam system, and condenser cooling system. These are regularly inspected to prevent wear and tear.
• 😀 In case of a loss of heavy water, emergency injection systems ensure water continues circulating to cool the fuel, supported by backup power systems.
• 😀 Backup power for cooling systems includes on-site plant-produced power, standby power generators, emergency power generators, and emergency batteries.
• 😀 Radiation containment is achieved through multiple barriers, including hardened ceramic pellets, ZIRLO alloy fuel rods, pressure tubes, and a concrete reactor building, all designed to withstand pressure and minimize radioactive releases.
• 😀 The CNSC establishes strict safety rules for nuclear activities and ensures compliance through regular inspections and testing, including ensuring that all systems meet or exceed safety standards to protect people and the environment.

Q & A

What are the main functions that nuclear power plants in Canada need to ensure?

Nuclear power plants in Canada must ensure three basic functions: controlling the reactor, cooling the fuel, and containing radiation.

How do CANDU reactors generate electricity?

CANDU reactors generate electricity by splitting atoms of natural uranium to create heat, which is then used to make steam that powers turbines and generators.

What is the role of the Canadian Nuclear Safety Commission (CNSC)?

The CNSC is responsible for establishing strict rules for nuclear activities in Canada and ensuring they are followed to protect people and the environment. They oversee the safety standards of nuclear power plants and inspect their operations regularly.

How are nuclear reactors in Canada shut down safely in case of an emergency?

Nuclear reactors in Canada have two independent and fast-acting shutdown systems: one involves rods dropping automatically to stop the reaction, and the second injects a liquid or poison to immediately halt the nuclear reaction. Both systems work without power or operator intervention.

What happens to nuclear fuel after it has been used in a reactor?

After nuclear fuel has been used in a reactor, it is removed and stored securely in a pool for six to ten years, where it continues to cool and is shielded from radiation by the water.

How do Canadian nuclear plants ensure the cooling of the reactor's fuel?

The cooling of nuclear fuel is managed by three main systems: the heat transport system, the steam system, and the condenser cooling system. Each system is regularly inspected and maintained to ensure proper cooling during normal operation and after a reactor shutdown.

What backup systems are in place at Canadian nuclear power plants if the main power source is lost?

Canadian nuclear plants have multiple backup power sources, including on-site power generated by the plant itself, at least two or three standby power generators, emergency power generators, and emergency batteries.

What safety measures are in place to contain radiation in CANDU reactors?

CANDU reactors have multiple containment layers, including hardened ceramic fuel pellets, fuel rods made of Zircaloy, pressure tubes, a metal tank called the calandria, reinforced concrete walls, and the reactor building itself. High-efficiency filters are also used to minimize radioactive releases.

How do Canadian nuclear plants manage internal pressure in the event of an accident?

In the event of an accident, nuclear plants have systems to manage internal pressure. In a single-unit station, this is done by spraying water from a dousing tank, and in multi-unit stations, pressure is reduced by releasing steam and gases to a vacuum building.

What steps does the Canadian Nuclear Safety Commission take if safety protocols are not followed at a nuclear plant?

If safety protocols are not followed, the CNSC takes immediate action to correct the situation. They regularly inspect plants and ensure compliance with safety standards, applying corrective measures as necessary.