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Thermodynamics Heat Transfer and Fluid Flow Volume 2 of 3 | Next
Figure 17 Radial Temperature Profile Across a Fuel Rod and Coolant Channel |
HEAT GENERATION
Heat Transfer
Maximum Local Linear Power Density
The maximum local linear power density when compared to the average linear power density
results in the definition of the nuclear heat flux hot channel factor. The nuclear heat flux hot
channel factor can be looked at as having axial and radial components that are dependent upon
the power densities and, thus, the flux in the radial and axial planes of the core. Once the hot
channel factor is known, the maximum local linear power density anywhere in the core can be
determined, as demonstrated in the following example.
Example:
If the nuclear heat flux hot channel factor is 1.83, calculate the maximum local linear
power density in the core for the previous example (the average linear power density
problem).
Solution:
Maximum linear power density
= HFHCF (Av linear power density)
= 1.83 (5.56) kW/ft
= 10.18 kW/ft
Normally, nuclear facility operators
Figure 16 Axial Temperature Profile
are provided with the above core
power
and
heat
generation
distributions, rather than having to
calculate them. In addition, various
monitoring
systems
are
always
employed to provide the operator with
a
means
of
monitoring
core
performance and the proximity of the
existing operating conditions to core
operational limitations.
Temperature Profiles
Additional areas of interest are the
temperature profiles found within the
core. A typical axial temperature
profile along a coolant channel for a
pressurized water reactor (PWR) is
shown in Figure 16. As would be
expected, the temperature of the
coolant will increase throughout the entire length of the channel.
HT-02
Page 48
Rev. 0
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