Neutron transport in matter The equation for neutron transport in matter has the form

called the telegraph equation (see, for instance, Appendix D of [16]) which shows a propagation term of the neutron density, of individual velocities v which we assume to be the same and constant here. In the diffusive regime, in reactor cores, this term is negligible. There exist situations (for instance, neutrino transport in supernovae)
where all terms must be kept owing to the discontinuities of the diffusive medium.
Proceeding as in (3.40), write the form of a Lagrangian from which this equation is derived.

Transcribed Image Text:

a 3 02 t v2 812 + =0, (6.49)