NUCLEAR-DEBRIS FORMATION
19
_nyv (n,),$
ty
ts
At equilibrium (denoted by *) the net rate is zero and
Away from equilibrium the equation integrates to
niV _ (ns);S
ty
_
t,
niv _ (n,)?S
ty
ts
—t/T
°
where 7 is the reduced molecular residence time t,t,/(t,+ t,). The first
bracketed term is the departure from equilibrium at time t, the sec-
ond is the initial departure from equilibrium, and e~‘’" is the exponen-
tial decay factor. The quantity t, is frequently called the lingering time
or die Verweilzeit.
The temperature can be incorporated explicitly into the rate equation by means of the definition of t,and Hlickel’s expression for t,:
t,= CT7%eUe/RT
where U, is the molar heat of adsorption and C is a constant. This can
be incorporated into the rate equation, combined witha suitable expres~
sion for temperature decay, and integrated.
Particle Diffusion
The fundamental formulas for heat conduction are
formally identical to those previously given for diffusion in the vapor
phase.
The former can be written in terms of a thermal flux Jy, a
thermal conductivity K, a temperature T, and a heat capacity per unit
volume c:
Jr =-KVT
aT
at? Vidr=0
By making the substitutions