Principle effects:

There are three principle effects related along with fuel densification which must be evaluated for reactors in all modes of operation.

a. an increase in the linear heat generation rate through an amount straightly proportional  to the reduces in pellet length

b. an increased  local  neutron  flux  and a local  power  spike  in the  axial  gaps in  the fuel column

c. a decrease  in the clearance gap heat conductance  among the pellets and the cladding.

That decrease in heat transmission capability will raise the energy stored inside the fuel pellet and will cause an increased fuel temperature.

For minimize the effects of fuel densification, plant process limit the maximum permissible rate at that power might be increased to ensure in that the temperature will not exceed 1200ºC during a loss of coolant accident. This allow the fuel pellets to shift slowly, along with less chance of becoming jammed in during the densification procedure, that in turn decreases the chance of cladding failure.