Critical experiments on gadolinium poisoned cluster-type fuel assemblies in heavy water lattices

Journal Article · Sat Jan 01 04:00:00 EST 1983 · Nucl. Sci. Eng.; (United States)

OSTI ID:5493947

Toshio, W; Isao, M

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), Journal Name: Nucl. Sci. Eng.; (United States) Vol. 83:1; ISSN NSENA
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
210400* -- Power Reactors
Nonbreeding
Otherwise Moderated or Unmoderated
ACTINIDE COMPOUNDS
BARYONS
BURNABLE POISONS
CHALCOGENIDES
COMPUTER CALCULATIONS
COMPUTER CODES
CONTROL ELEMENTS
ELEMENTARY PARTICLES
FERMIONS
FINE STRUCTURE
FUEL ASSEMBLIES
FUEL ELEMENT CLUSTERS
FUEL ELEMENTS
FUEL PELLETS
FUEL PINS
GADOLINIUM COMPOUNDS
GADOLINIUM OXIDES
HADRONS
HEAVY WATER MODERATED REACTORS
KINETICS
MATERIALS
NEUTRON ABSORBERS
NEUTRON FLUX
NEUTRONS
NUCLEAR POISONS
NUCLEAR REACTION KINETICS
NUCLEONS
OXIDES
OXYGEN COMPOUNDS
PELLETS
POWER DISTRIBUTION
QUANTITY RATIO
RADIATION FLUX
RARE EARTH COMPOUNDS
REACTION KINETICS
REACTIVITY
REACTIVITY COEFFICIENTS
REACTIVITY INSERTIONS
REACTOR COMPONENTS
REACTOR LATTICES
REACTOR MATERIALS
REACTOR SAFETY EXPERIMENTS
REACTORS
SELF-SHIELDING
SHIELDING
THERMAL NEUTRONS
URANIUM COMPOUNDS
URANIUM DIOXIDE
URANIUM OXIDES
VOID COEFFICIENT
W CODES