The Mean Neutron Generation Time is the inverse of the mean Neutron Generation Rate. It represents the time that it takes for a neutron to generate another neutron.
$$\Lambda=\frac{\text{# of Neutrons}}{\text{Fission Neutron Production Rate}}$$
or
$$\Lambda=\frac{\frac{1}{v}\phi}{\nu v \Sigma_f}$$
These equations assume that the neutrons are integrated over energy and space. \(\Lambda\) is around \(10^{-4}\) for thermal reactors and \(10^{-6}\) for fast reactors.
TRIGA MK 2 Neutronics Model – uses a \(\Lambda\) of 60e-6
Delayed Neutron Precursor – uses a \(\lambda\) of 5.0e-4
Sources
- [1] Nuclear Engineering Lectures, NE560 – Lecture 1: Intro to Kinetics and Dynamics, (Aug. 17, 2020). Accessed: May 25, 2023. [Online Video]. Available: https://www.youtube.com/watch?v=OPfowMUJCrk