By safety, we mean that working with radioactive systems and materials must be safe. We ensure that this work is always performed in a controlled way without harming the surroundings or our employees.
By security, we mean that the industrial plant (the nuclear plant, factory or location) is well protected from man-made disasters. In this industry, we work with radioactive materials and complex technology. Our security measures ensure that third parties cannot access them.
In response to people's concerns about nuclear safety, a great deal of attention is devoted to the safety of nuclear plants. In our country, the focus is on Borssele: the only nuclear plant operating in the Netherlands. For that reason, we inspect the safety of the nuclear plant. The nuclear plant in Zeeland is robust and has a large safety margin. Borssele has five safety barriers that protect it from external disasters. It is impossible to break through the five barriers from the outside in one coordinated action and cause a nuclear incident. Conversely, the design ensures that under all process conditions, radioactivity remains inside the safety barriers.
From inside to outside, the nuclear plant has the following barriers:
Barrier 1: Ceramic nuclear fuel tablets
The porcelain nuclear fuel tablet is the first barrier. Around ninety percent of the radioactivity remains sealed in the matrix of the porcelain (uranium oxide). Only the very volatile substances (noble gases, iodine, caesium) leave the nuclear fuel tablet.
Barrier 2: Hermetically sealed nuclear fuel rods
The nuclear fuel tablets are stacked in a hermetically sealed zirconium tube: gas and liquid proof. The nuclear fuel rod keeps most of the volatile radioactive substances inside.
Barrier 3: Concrete bunkers containing the primary system
The primary system contains the reactor vessel, pipes and steam generators. This is a closed circuit through which refrigerant (conditioned water) is pumped. This water is under a pressure of 155 bar so that it doesn't boil. The primary system consists of centimetres-thick steel parts of the highest quality and with a very large safety margin. Radioactive substances cannot escape. The primary system is located in bunkers. The concrete provides radiation protection and protects the installation from external disasters.
Barrier 4: Containment
The primary system is contained in a robust steel sphere. This ensures that no radioactivity can escape outside in the event of an incident. The sphere is a strong, air-tight structure and can capture internal gas and steam explosions. If an incident occurs, emissions from the primary system are contained.
Barrier 5: Reactor building
All the systems are sealed in the reactor building, recognisable from the outside by the top half of the sphere that is in the characteristic concrete dome. The building forms the last physical barrier between the primary system and the surroundings. Conversely, the concrete building is the first barrier for external disasters on the way to the core.
More information about the safety of Borssele nuclear plant is available on www.epz.nl.
All nuclear installations in our country are monitored and secure. Here too we explain the system based on the nuclear plant. After the heightened terror threat, security has become more stringent. The nuclear plant is surrounded by security rings. The outer security ring acts as a detection zone, with the other rings having a delaying effect. The inner rings are the real physical barriers that trap intruders. If intruders are detected, an alarm alerts the security guards and possibly a government emergency response team. The subsequent rings have a delaying effect, which increases the reaction time. The inner rings are closed so that the complex is made inaccessible.
Besides physical security, there is also a lot of attention for cybersecurity. The vital computer systems of the nuclear industry cannot be approached from the outside and are permanently secured or monitored. External ICT resources are not simply granted access to the installation, and there is close consultation with the government with respect to identifying and combatting cybersecurity threats. Finally, employees are screened, and visitors to the nuclear companies are supervised. All employees are given background checks and must be able to present a certificate of conduct. Exercises in dealing with safety incidents are regularly carried out with the government. Obviously, very few details are provided about the security.
Urenco Nederlands is a nuclear company that works with top-secret technology. For that reason, additional security measures apply.