- Nuclear installations in Germany
- Safety in nuclear energy
- Legal bases
- Licensing and supervision
- Safety philosophy
- Technical barriers
- Disturbances affecting safety
- Digital safety instrumentation and control
- Precautions and emergency response
- National committees
- International co-operation
- Reportable events
- Reporting procedure
- Incident registration centre
- International Nuclear Event Scale (INES)
- Reportable events in nuclear installations
- Reports on reportable events
- Shutdown and decommissioning
- Nuclear accidents
- What is nuclear waste management?
- Design approvals of transport packages
- Interim storage facilities
- What are interim storage facilities?
- Licensing of interim storage facilities for nuclear fuels
- Central interim storage facilities
- Decentralised interim storage facilities
- Interim storage facilities for radioactive waste with negligible heat generation
- Federal custody of nuclear fuels
- What is nuclear waste management?
- Foundation and development
- President of the BfE
- Laws and regulations
- Frequently applied legal provisions
- Handbook nuclear safety and radiation protection
- 1A Nuclear and radiation protection law
- 1B Other laws
- 1C Transport law
- 1D Bilateral agreements
- 1E Multilateral agreements
- 1F EU law
- 2 General administrative provisions
- 3 Announcements of the BMU and the formerly competent BMI
- 4 Relevant provisions and recommendations
- 5 Nuclear Safety Standards Commission (KTA)
- 6 Key committees
- Annex to the NS Handbook
- A 1 English translations of laws and regulations
- Dose coefficients to calculate radiation exposure
- Legal Basis
- BfE Topics in the Bundestag
As a passive safety device, technical barriers are a central component of reactor safety in German nuclear power plants. Several sequential technical barriers (multi-barrier system) are to retain the radioactive materials in normal operation and also in case of incidents. The barriers work independently of each other and at all levels of the effective safety concept.
The following technical barriers are available:
The fuel is in a solid, ceramic substance, the fuel tablets, also referred to as pellets.
In normal operational conditions, the major part of the radioactive materials generating in nuclear fission (activation and fission products) remain sealed in the heat-resistant crystal lattice of the fuel tablets.
Fuel rod cladding
The fuel tablets are sealed in the fuel rods in cladding tubes made from a zirconium alloy "Zirkaloy". The fuel rod cladding is tight and pressure-resistant. It prevents the radioactive fission products from getting into the coolant.
Several fuel rods are combined to fuel elements by means of a support structure. Depending on the reactor type, a varying amount of fuel elements is used in the reactor core.
Pressure retaining boundary
The fuel elements are in a thick-walled reactor pressure vessel made from steel, where the nuclear chain reaction takes place in a controlled way. The heat is dissipated with water under pressure without boiling (pressurised water reactor) or as steam (boiling water reactor).
The reactor pressure vessel and the associated piping for cooling water and steam form the so-called "pressure retaining boundary". It resists high temperatures and pressures and encloses the radioactive inventory during all normal and faulty modes of operation.
Reactor pressure vessel (reactor containment)
The reactor pressure vessel is located inside a gas-tight containment. This containment serves to safely enclose the radioactive inventory, even in case of incidents.
The reactor pressure vessel is in the reactor building which is ventilated and vented in a controlled way. The other purpose of the building is to protect against external influences, e.g. the influence of weather and pressure waves from explosion.
State of 2016.10.11