Fuel Flashcards
What are the major components of a fuel assembly?
Fuel Pellet Fuel Cladding Water Channel Water Spacer Rod Upper and Lower Tie Plate Fuel Rod Spacers Fuel Channel Orificed Fuel Support
What is the benefit of a partial fuel rod?
Allows for additional water in upper region
Improved MCPR margin
Helps to flatten nerutron flux across bundle
What is the purpose of a Fuel Rod?
Contains fuel pellets to generate heat from fission
What is the purpose of the lower tie plate?
Holds the lower end plug for each rod, routes coolant past fuel rod. Fites into fuel support piece and provides sealed surface for fuel channel and finger springs
What is the purpose of installing gadolinium in some fo the fuel rods?
Allows for larger mass of fissionable material without more control rods and allows better axial and radial flux shaping.
What is the primary material for cladding?
Zircaloy - excellent corrosion resistance and low neutron absorption cross section
What is installed between the pellet and fuel cladding?
Helium gas to increase heat transfer coefficient
What is the fuel rod plenum and Plenum spring and what does it do?
Fuel Rod plenum is a space at the top of the rod taht allows space for accumulation of fission gas.
Plenum spring applies pressure to fuel stack which minimizes pellet movement
How many fuel rods are threaded?
8
What is the Water Spacer Rod?
Hollow zircaloy tube Located near the center of the fuel bundle, that allows coolant through the rod to increase netron moderation in the interior of the fuel bundle to flatten radial bundle dist.
What are the upper and lower tie plates?
Support the fuel weight and positions bundle during all phases.
Lower tie plate seats in fuel support piece and provides vertical and lateral support for rods and water channel.
How is the shape and clearance of the fuel rods maintained?
Fuel Rod Spacers
What is the Fuel Channel?
It encloses the fuel bundle and separates the coolant flow through the bundle (90%) and bypass flow (10%). Finger springs control bypass flow to control rod and NI cooling.
What is the purpose of the Orificed Fuel SUpport?
Transmits weight of fuel to control guide tubes and reactor vessel.
Controls flow amount to bundles
How do the peripheral orifices compare to the inner orifices?
Peripheral orifices are smaller. Higher power bundles are in the center and require larger flow.
