Criticality (status)

Criticality is the state of a nuclear chain reacting medium when the chain reaction is just self-sustaining (or critical), that is, when the reactivity is zero. The term may also be applied to states in which the reactivity is greater than zero.[1]

Applications

In the context of a nuclear reactor, particularly in a nuclear power plant, criticality refers to the normal operating condition of a reactor, in which nuclear fuel sustains a fission chain reaction. A reactor achieves criticality (and is said to be critical) when each fission event releases a sufficient number of neutrons to sustain an ongoing series of reactions.[2]

The International Atomic Energy Agency also defines the first criticality date as the date when the reactor is made critical for the first time.[3] This is an important milestone in the construction and commissioning of a nuclear power plant. For example, Qinshan 1, China's first domestically designed and constructed nuclear power plant, achieved first criticality on 31 October 1991.[4]

See also

References

  1. ↑ "Criticality" (PDF). IAEA Safety Glossary. International Atomic Energy Agency. 2007. p. 46. Retrieved 17 February 2014.
  2. ↑ "Criticality". Glossary. US Nuclear Regulatory Commission. 11 December 2013. Retrieved 17 February 2014.
  3. ↑ "First Critical Date". Glossary. International Atomic Energy Agency. Retrieved 17 February 2014.
  4. ↑ "QINSHAN-1 Status Page". Power Reactor Information System. International Atomic Energy Agency. Retrieved 18 February 2014.
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