The main benefit of using a moderator in a nuclear explosive is that the amount of fissile material needed to reach criticality may be greatly reduced.

Construction was completed and the reactor reached initial criticality on March 23, 1974.

But now we've suddenly multiplied the connecting links, the networks have all merged together, and we've reached criticality.

Unit 1 reached initial criticality on March 8, 1988 and went into commercial operation on August 25.

Unit 2 reached initial criticality on March 12, 1989 and went into commercial operation on June 19.

Due to a procedural error, the mixture contained 3.27 kg of plutonium, which reached criticality for about 200 microseconds.

The reactor reached criticality on December 2, 1957, and remained in operation until October 1982.

In 1996, Kamini (reactor) reached criticality.

The S1W reactor reached criticality on March 30, 1953.

The first unit's construction started in 1963, and the second unit reached criticality in 1988.