Emergency Response Planning

Despite all the measures described above, radioactive releases may occur. Nuclear safety cannot exclude this probability however this probability is very low. The radiological consequences in this case depend on the type of event that led to releases and are also calculated based on the weather conditions. The purpose of the on-site emergency plan is to protect staff working at the site in the event of an incident or accident and to limit off-site consequences of an accident. Measures for protecting the public from radioactive releases include off-site emergency plans prepared for each site. Public authorities implement the off-site emergency plan, which organises emergency operations to limit public exposure to radiation in the event of releases.

Level 5 - Emergency response planning
Although these events are very unlikely, they cannot be “practically eliminated”. For DECs with core melt, maintaining the integrity of the containment is the main objective. This also implies that the cooling and stabilization of the molten fuel and the removal of heat from the containment need to be achieved in the long term.

The results are expressed in terms of effective doses from the radioactive releases (external and internal exposure), ground fallout, ingestion and equivalent doses to the thyroid (primarily due to iodine).

The public-safety measures that can be implemented during the emergency phase are indicated in the offsite emergency plans. The prefect may consider a number of public-safety measures:

  • Sheltering. Under some conditions, people may be instructed to take shelter in their homes, schools, or office buildings. Depending on the type of structure, sheltering can significantly reduce a person’s dose compared to remaining outside. Sheltering is a protective action that keeps people indoors, such as at home, the office, school, or a shopping mall to reduce exposure to radioactive material.
  • Ingestion of potassium-iodide tablets. Potassium-iodide (KI) is a compound that helps prevent the thyroid from absorbing radioactive iodine, one of several radioactive materials that could be present in a release from a nuclear power plant accident. If taken within the appropriate time and at the appropriate dosage, KI blocks the radioactive iodine from being absorbed by the thyroid gland and reduces the risk of thyroid cancers and other diseases. KI does not protect against any other inhaled radioactive materials, nor will it offer protection from external exposure to radiation.

Evacuation. Evacuation does not always call for completely emptying the pre-defined zone around a nuclear power plant. In most cases, the release of radioactive material from a plant during a major incident would move with the wind, not in all directions surrounding the plant. The release would also expand and become less concentrated as it travels away from a plant.

Plant States

nuclear power plant states - accident conditions

 
References:
Nuclear and Reactor Physics:
  1. J. R. Lamarsh, Introduction to Nuclear Reactor Theory, 2nd ed., Addison-Wesley, Reading, MA (1983).
  2. J. R. Lamarsh, A. J. Baratta, Introduction to Nuclear Engineering, 3d ed., Prentice-Hall, 2001, ISBN: 0-201-82498-1.
  3. W. M. Stacey, Nuclear Reactor Physics, John Wiley & Sons, 2001, ISBN: 0- 471-39127-1.
  4. Glasstone, Sesonske. Nuclear Reactor Engineering: Reactor Systems Engineering, Springer; 4th edition, 1994, ISBN: 978-0412985317
  5. W.S.C. Williams. Nuclear and Particle Physics. Clarendon Press; 1 edition, 1991, ISBN: 978-0198520467
  6. G.R.Keepin. Physics of Nuclear Kinetics. Addison-Wesley Pub. Co; 1st edition, 1965
  7. Robert Reed Burn, Introduction to Nuclear Reactor Operation, 1988.
  8. U.S. Department of Energy, Nuclear Physics and Reactor Theory. DOE Fundamentals Handbook, Volume 1 and 2. January 1993.

Nuclear Safety:

  1. IAEA Safety Standards, Safety of Nuclear Power Plants: Design, SSR-2/1 (Rev. 1). VIENNA, 2016.
  2. IAEA Safety Standards, Safety of Nuclear Power Plants: Commissioning and Operation, SSR-2/2 (Rev. 1). VIENNA, 2016.
  3. IAEA Safety Standards, Deterministic Safety Analysis for Nuclear Power Plants, SSG-2 (Rev. 1). VIENNA, 2019.
  4. IAEA TECDOC SERIES, Considerations on the Application of the IAEA Safety Requirements for the Design of Nuclear Power Plants, IAEA-TECDOC-1791. VIENNA, 2016.
  5. Safety Reports Series, Accident Analysis for Nuclear Power Plants with Pressurized Water Reactors. ISBN 92–0–110603–3. VIENNA, 2003.
  6. Appendix A to 10 CFR Part 50, “General Design Criteria for Nuclear Plants.”
  7. NUREG-0800, Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants: LWR Edition.
  8. Nuclear Power Reactor Core Melt Accidents, Science and Technology Series. IRSN – Institute for Radiological Protection and Nuclear Safety. ISBN: 978-2-7598-1835-8
  9. ANSI ANS 51.1: Nuclear Safety Criteria for the Design of Stationary Pressurized Water Reactor Plants, 1983.

See above:

Nuclear Safety