BWR fuel assembly with improved spacer and fuel bundle design for enhanced thermal-hydraulic performance

Patent · Tue Nov 24 04:00:00 EST 1987

OSTI ID:5590311

Mildrum, C M; Taleyarkhan, R P

In a fuel assembly having a bundle of elongated fuel rods disposed in side-by-side relationship so as to form an array of spaced fuel rods, an outer tubular flow channel surrounding the fuel rods so as to direct flow of coolant/moderator fluid along the fuel rods, a hollow water cross extending centrally through and interconnected with the outer flow channel so as to divide the channel into separate compartments and the bundle of fuelrods into a plurality of mini-bundles thereof being disposed in the compartments, and spacers axially displaced along the fuel rods in each of the mini-bundles thereof. Each spacer is composed of inner and outer means which together define spacer cells at corner, side and interior locations of the spacer and have respective protrusions formed thereon which extend into cells so as to maintain the fuel rods received through the spacer cells in laterally spaced relationships. The improvement is described which comprises: (a) a generally uniform poison coating within at least a majority of the fuel rods; (b) a predetermined pattern of fuel enrichment with respect to the fuel rods of each mini-bundle thereof which together with the uniform poison coating within the fuel rods ensures that the packing powers of the fuel rods in the corner and side cells of the spacers are less than the peaking power of a leading one of the fuel rods in the interior cells of the spacers; and (c) each of the fuel rods being received through the cells of each spacer having a diametric size smaller than that of each of the fuel rods received through the side and interior cells of each spacer, the diametric sizes of each of the fuel rods received through the side and interior cells of each spacer being generally equal.

• Assignee: Westinghouse Electric Corp., Pittsburgh, PA
• Patent Number(s): US 4708845
• OSTI ID: 5590311
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
210100* -- Power Reactors
Nonbreeding
Light-Water Moderated
Boiling Water Cooled
BWR TYPE REACTORS
COATINGS
CONTROL
COOLANTS
FLUID MECHANICS
FLUID POISON CONTROL
FUEL ASSEMBLIES
FUEL ELEMENTS
FUEL RODS
HYDRODYNAMICS
HYDROGEN COMPOUNDS
MATERIALS
MECHANICS
NUCLEAR POISONS
OXYGEN COMPOUNDS
POSITIONING
PROTECTIVE COATINGS
REACTOR COMPONENTS
REACTOR MATERIALS
REACTORS
ROD BUNDLES
SPACERS
THERMODYNAMICS
WATER
WATER COOLED REACTORS
WATER MODERATED REACTORS