\section*{Problem 6}
\subsection*{Part A}

Withdrawing the control rods will move power production towards the upper half
of the core. Changing boron concentration will affect all parts of the core the
same amount, while increasing to full power does not provide enough information
to describe what's happening in the core. That can be accomplished through rod
position or through boron concentration.

Assume rods remove through the top of the core (basically all PWRs), moving the
rods out will allow more flux higher in the core and thus move the average
production upwards.

\subsection*{Part B} 

This happens because the moderator is the coolant, and the
coolant is colder as it enters the core at the bottom of the core. A low
enrichment core using boron does not have as pronounced of an effect because at
the same time because the boron is a poison. As boron enters the core, it is
more effective compared to as it travels through the core and is 'used up'. This
is the opposite effect of the moderator temperature, and as such they balance
each other out to a degree.