ORNL-2106 - the Molten Salt Energy Technologies Web Site

ANP PROJECT PROGRESS REPORT
ot(E) = microscopic total cross section
at energy E, cm2,
ot(Eo) = microscopic total cross section
at energy, E,, cm2,
9 9
X = scalar distance from source
point measured in units of mean
free path at energy E,,
+
X = position vector from source
point,
f(E,Q,E ',a ') = scattering kernel,
+ +
G(A,E,Q) = particle current, particles per
unit energy at energy E per unit
solid angle in the direction 6per
. square mean free path (at energy
. E,) at position A,
+
S(E,Q) = source strength, particles per
unit energy at energy E fer unit
solid angle in direction Q.
Equation 1 is independent of the nuclear density
thus G(A,E,H) is also inde-
This means that if two ex-
periments are set up with the same point source
but with different densities p1 and p2 and ttie
current is measured in each experiment at positions
such that
then
(3)
The significance of Eg. 3 can be realized if hand
G are reduced to conventional units. The relation
between distance r (measured in centimeters) and
X is given by
9 9
(4) h = No,(E,)r ,
where N is the nuclear density of the medium. The
conventional particle current can be defined as
F(?,E,~) given in particles per unit energy at
energy E per unit solid angle in direction 6 per
cm2 at position r. The relation between F and G
is then
266
By using Eq. 4, Eq. 2 becomes
9 Nl 9 p1 9
r2 =- r1 = - r1
N2 p2
and by using Eq. 5, Eq. 3 becomes
which is the desired transformation. Proper inte-
gration of Eq. 7 gives the flux transformation.as
and the dose rate transformation as
These transformations can be applied to much of
the TSF data, but the application is not entirely
general.2 To make full use of the transformations
it will be necessary to obtain additional data at
the TSF at several separation distances so that
the measurements can be interpolated and applied
at any altitude.
ENERGY ABSORPTION RESULTING FROM
GAMMA RADIATION INCIDENT ON A
MULTIREGION SHIELD WITH
SLAB GEOMETRY
S. Auslender3
The code for a Monte Carlo calculation of energy
deposition in a multiregion shield with slab
geometry4 has been used to obtain the results for
1-Mev gamma rays incident on a slab consisting of
regions of fuel, Inconel, sodium, and Inconel again.
A diagram of the composite slab is shown in Fig.
5.1.1, which gives the normal thicknesses in
30n assignment from Pratt & Whitney Aircraft.
4S. Auslender, ANP Quar. Prog. Rep. March 10, 1956,
ORNL-2061, p 223.
c
r