Vattenfall - Safety

Nuclear power safety

Safety must always be given top priority, in order to protect the general public, the environment and the people working at nuclear power plants. Vattenfall is constantly investing in improvements in already advanced technology and safety features.

Nuclear power is a major energy sources, and will, due to its very low CO₂ emissions and overall good environmental performance, continue to be an important part of the electricity system for the foreseeable future.

Safety management and safety culture at Vattenfall

In 2007, Vattenfall conducted a thorough review of the Group´s nuclear safety work. Internationally renowned experts have also conducted an in-depth analysis. As a conclusion, a comprehensive action programis now under way which is aimed at strengthening the safety culture at Vattenfall’s nuclear power plants and more clearly outlining safety management within the Group.

Safety work at a nuclear plant

When the uranium atom is split in the fission process, radioactive substances are created which emit ionising radiation. The purpose of all safety work is to prevent the radiation from escaping outside the facility. Nuclear power plants therefore have safety systems and barriers of many different types. In addition, the safety culture and safety work represent important aspects of staff training. In Sweden, the safety work is supervised by the Swedish Radiation Safety Authority.

Swedish Radiation Safety Authority (new window)

Three stages of safety

Safety in a nuclear plant is made up of three stages:

Preventing faults

Reducing the effects in the event a fault nevertheless occurs

Alleviating the consequences of any breakdown

Preventing faults

• Multi-barrier safety system

Read about the Multi-barrier safety systems

• Regular checking and testing of all safety systems
• Simulator training – the nuclear power operators train regularly in exact copies of their own control rooms
• The 30-minute rule – if a fault occurs, everything that must be done within half an hour is done automatically. This rule exists to give personnel time to think.

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Reducing the effects in the event a fault nevertheless occurs

• Doubling or multiplying safety systems with different technical solutions – if the first one does not work, the next one takes over.
• Automatic reactor trip – if a fault occurs, all the control rods are lowered into the reactor core and uranium fission stops within a few seconds.
• The safety systems are spread around the plant so that they are not all knocked out in the event of a fire, for example.
• The risk of a fault bypassing all the protection systems is minimal.

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Alleviating the consequences of any breakdown

A nuclear power plants have several protective barriers to prevent radioactive substances from escaping to the surroundings:

• The fuel. Does not dissolve readily in air or water, and does not melt below 2,900°C
• Fuel rods. Rods of special metal (zircaloy), which is similar to stainless steel.
• Reactor tank. Made of 15-20 cm thick steel.
• Reactor containment. Metre-thick concrete with cast-in, gas-tight steel plate. In the event of an accident, the space is cooled by a sprinkler system, which also binds radioactive particles.
• Safety filter. Even if all the safety systems cease to function, radioactivity must not leak out. There are therefore special filters that deal with 99.9% of the radioactive substances.

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Read about:

Boiling water reactor

Pressure water reactor