On Some Fundamental Peculiarities of the Traveling Wave Reactor

Table 2

Moderating and absorbing properties of some substances, moderator layer width estimate for moderating neutron from  MeV to = 0.1 MeV.

Moderator	Mass number,	Mean logarithmic energy,	Density, , g/cm	Impacts number required for moderating,	Neutron mean free path,	Moderator layer width, , cm
Be	9	0.21	1.85	11	1.39	15.3
C	12	0.158	1.60	15	3.56	53.4
HO	18	0.924	1.0	2.5	16.7	41.6
O + B				2.5	10.0	25.0
He	4	0.425	0.18	5.41	11.2	60.7