Critical experiments on gadolinium poisoned cluster-type fuel assemblies in heavy water lattices
The physical behavior of burnable poison fuel pins, containing 0.1, 0.5, and 1.0 wt% Gd/sub 2/O/sub 3/ in 1.5 wt% UO/sub 2/ pellets, has been studied through the measurements of reactivity change, coolant void reactivity, local power distribution, and thermal neutron flux distribution including fine structure, using a heavy-water-moderated, cluster-type fuel lattice. A new technique for utilizing a burnable poison has been developed using a gadolinium absorber rod inserted into the center of the cluster-type fuel assembly. Its physical behavior has been studied through the measurements of accompanying reactivity change, coolant void reactivity, local power distribution, and thermal neutron flux distribution. When the Gd/sub 2/O/sub 3/ content of the fuel pellets is more than 0.5 wt%, the reactivity effect is reduced largely due to the saturation of the thermal neutron self-shielding effect in the poisoned fuel pin. A gadolinium absorber rod inserted in the center of the fuel assembly, although it causes a small increase in local power peaking, is effective in the control of the initial excess reactiv ity and favorably affects the coolant void reactivity. An accurate calculation by the WIMS-D code requires division of the fuel pellet region into more than five mesh intervals owing to the enhancement of the thermal neutron selfshielding effect due to absorption by the gadolinium in the poisoned fuel pins.
- Research Organization:
- Oarai Engineering Center, Power Reactor and Nuclear Fuel Development Corporation, 4002 Oarai-machi, Ibaraki-ken
- OSTI ID:
- 5493947
- Journal Information:
- Nucl. Sci. Eng.; (United States), Vol. 83:1
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
BURNABLE POISONS
FUEL ELEMENT CLUSTERS
NUCLEAR REACTION KINETICS
REACTOR SAFETY EXPERIMENTS
HEAVY WATER MODERATED REACTORS
COMPUTER CALCULATIONS
CONTROL ELEMENTS
FINE STRUCTURE
FUEL PELLETS
FUEL PINS
GADOLINIUM OXIDES
NEUTRON ABSORBERS
NEUTRON FLUX
POWER DISTRIBUTION
QUANTITY RATIO
REACTIVITY
REACTIVITY INSERTIONS
REACTOR LATTICES
SELF-SHIELDING
THERMAL NEUTRONS
URANIUM DIOXIDE
VOID COEFFICIENT
W CODES
ACTINIDE COMPOUNDS
BARYONS
CHALCOGENIDES
COMPUTER CODES
ELEMENTARY PARTICLES
FERMIONS
FUEL ASSEMBLIES
FUEL ELEMENTS
GADOLINIUM COMPOUNDS
HADRONS
KINETICS
MATERIALS
NEUTRONS
NUCLEAR POISONS
NUCLEONS
OXIDES
OXYGEN COMPOUNDS
PELLETS
RADIATION FLUX
RARE EARTH COMPOUNDS
REACTION KINETICS
REACTIVITY COEFFICIENTS
REACTOR COMPONENTS
REACTOR MATERIALS
REACTORS
SHIELDING
URANIUM COMPOUNDS
URANIUM OXIDES
210400* - Power Reactors
Nonbreeding
Otherwise Moderated or Unmoderated