The safe enclosure of the radioactive inventory of a nuclear facility is effected according to the multiple barrier principle, i.e., to release radioactive substances, these must pass different barriers connected in series. The barriers of a nuclear reactor are e.g.:

  • Retention of fission products in the nuclear fuel itself,
  • Enclosure of the nuclear fuel in cladding tubes,
  • Enclosure of fuel elements in the reactor pressure vessel and reactor coolant system,
  • Gastight containment.

Safety barriers of a nuclear power plant to avoid release of radioactive substances and ionizing radiation