Term
Nuc Fuel
Describe the number of fuel bundles. |
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Definition
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Term
Nuc Fuel
Describe a control cell. |
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Definition
| A control rod and the four fuel assemblies. |
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Term
Nuc Fuel
Describe the makeup and function of the cladding. |
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Definition
-92% Zirconium.
-160" long.
-Contains the fuel pellets. |
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Term
Nuc Fuel
Describe the lower tie plate. |
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Definition
-Ties fuel bundle together.
-2 adjacent sides have holes drilled for bypass flow. |
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Term
Nuc Fuel
Describe the expansion spring. |
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Definition
-Provides compression loading of fuel rods.
Located outside of fuel pin. |
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Term
Nuc Fuel
Describe the finger springs. |
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Definition
-Holds the channel out at the bottom for leakage path.
-4 per bundle. |
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Term
Nuc Fuel
Describe the plenum spring. |
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Definition
| -Inside fuel rod for expansion |
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Term
Nuc Fuel
Describe the upper tie plate. |
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Definition
| Ties assembly together at top of fuel. |
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Term
Nuc Fuel
Describe 5 methods for fuel verification. |
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Definition
-Channel fastener assemblies in center of cell.
-ID bosses point towards center of cell.
-Channel spacer buttons adjacent to each other.
-Bundle serial numbers readable from center of cell.
-Cell to cell symmetry. |
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Term
Nuc Fuel
Describe zirc hydriding. |
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Definition
-Occurs inside fuel rod when free H2 combines chemically with Zirconium.
-Blisters on inside of clad wall and thru wall.
-Need H2 from water and fuel rod contaminants during manufacturing.
-Eliminated by helium backfill. |
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Term
Nuc Fuel
Describe pre-pressurized fuel benefits. |
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Definition
-10 atmospheres of He.
-Promotes heat transfer. |
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Term
Nuc Fuel
Describe pellet cladding interaction and prevention. |
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Definition
-Excessive localized cladding strain (pellet expands faster than clad).
-Prevented by:
-Pellet chamfering.
-Pre-conditioning. |
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Term
Nuc Fuel
Describe the 3 primary leakage flowpaths. |
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Definition
-Fuel support lower tie plate.
-Lower tie plate holes (2 per assembly).
-Channel-lower tie plates. |
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