The nuclear chain reaction has a positive feedback component whenever a critical mass is created; specifically, excess neutrons are produced for every fission.

Inside a nuclear reactor, these excess neutrons must be controlled as long as a critical mass exists.

The most significant and effective control mechanism is the use of control rods to absorb the excess neutrons.

We'll control the nuclear reaction with cadmium rods that capture excess neutrons before they strike uranium atoms.

"We see no evidence for any excess neutrons," Dr. Saltmarsh said.

During the detonation of the primary fission bomb stage, excess neutrons released by the chain reaction split lithium-6 into tritium plus helium-4.

Pu-240 undergoes spontaneous fission at an appreciable rate, and that releases excess neutrons.

Most cores that use this fuel are "high leakage" cores where the excess leaked neutrons can be utilized for research.

Three of the first five runs showed ratios between 1.5 and 2, implying excess neutrons of between 50 and 100 per cent.

A new osmium isotope with excess neutrons.