Radiogenic Lead with Dominant Content of ²⁰⁸Pb: New Coolant and Neutron Moderator for Innovative Nuclear Facilities

Table 2

Properties of neutron moderators at 20°C.

Moderator	Average logarithmic energy loss, 𝜉	Moderating ratio, 𝜉Σ𝑠/Σ^𝑡ℎ𝑎	Neutron age; τ (cm^2) (0.1 MeV → 0.5 eV)	Diffusion length L (cm)	Mean lifetime of thermal neutrons 𝑇th (ms)
H2O	0.95	70	1.35	3	0.2
D2O	0.57	4590	58	147	130
BeO	0.17	247	66	37	8
^12C	0.16	242	160	56	13
Pbnat	0.00962	0.6	3033	13	0.8
^208Pb	0.00958	477	2979	341	598