Civil Engineering Reference
In-Depth Information
Fig. 2.6
Spatial
distribution of the thermal
neutron density in a
Pressurized Water Reactor
core with partially inserted
control rods [
11
]
neutron density distribution. The absorber- or control-rods are partially inserted in
axial direction in the PWR core. The control rods absorb neutrons and are respon-
sible for the spatial distortions of the thermal neutron flux. They influence the
criticality level and the spatial power distribution.
The spatial distribution of the neutrons with a certain velocity or kinetic energy
and flight direction can be described by the Boltzmann neutron transport equation
or by Monte Carlo methods [
1
-
4
]. For both cases, numerical methods in one-, two-
or three-dimensional geometry were developed. Computer program packages
(deterministic codes for the solution of the Boltzmann transport equation and
Monte Carlo codes using stochastic solution methods) are available for various
applications [
1
,
3
-
5
,
18
,
38
].
