Influence of burnable gadolinia poison on coolant void reactivity in pressure-tube-type heavy water reactor

Journal Article · Mon Nov 01 04:00:00 EST 1993 · Nuclear Science and Engineering; (United States)

OSTI ID:5804985

Kowata, Yasuki; Fukumura, Nobuo ^[1]

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1. Power Reactor and Nuclear Fuel Development Corp., Oaraimachi, Ibarakiken (Japan)

The influence of burnable gadolinia poison in fuel assemblies on coolant void reactivity for a pressure-tube-type boiling light-water-cooled heavy water reactor is investigated in critical experiments using the Deuterium Critical Assembly (DCA) and theoretical analyses by the WIMS-D4/CITATION code system. The experimental and the calculated void reactivities agrees within [+-]0.2 $. A number of gadolinia-poisoned fuel assemblies are dispersively loaded in the central region of the DCA core together with unpoisoned fuel assemblies. Each gadolinia-poisoned assembly is composed of three or four Gd[sub 2]O[sub 3]-poisoned UO[sub 2] fuel rods as well as unpoisoned fuel rods. The gadolinia concentration is varied from 0.0 to 1.0 wt%. The void reactivity in the core becomes less negative with the addition of gadolinia but become saturated at a Gd[sub 2]O[sub 3] concentration of [approximately]0.5 wt%. The void reactivity becomes much less negative with a higher loading ratio of the gadolinia-poisoned assemblies in the core and as the gadolinia-poisoned fuel rods are arranged in the outer layers of the assembly. When the fissile nuclide in the pellets of the unpoisoned fuel assembly is changed from uranium to plutonium, the incremental positive shift of the void reactivity can be reduced because of the increase in the 0.3-eV thermal resonance absorption of [sup 239]Pu and [sup 241]Pu.

• OSTI ID: 5804985
• Journal Information: Nuclear Science and Engineering; (United States), Journal Name: Nuclear Science and Engineering; (United States) Vol. 115:3; ISSN NSENAO; ISSN 0029-5639
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
210400* -- Power Reactors
Nonbreeding
Otherwise Moderated or Unmoderated
ABSORPTION
ACTINIDE COMPOUNDS
ACTINIDE ISOTOPES
ACTINIDE NUCLEI
ALPHA DECAY RADIOISOTOPES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BURNABLE POISONS
BURNUP
CHALCOGENIDES
COMPUTER CODES
COOLANTS
EVEN-ODD NUCLEI
FUEL ASSEMBLIES
GADOLINIUM COMPOUNDS
GADOLINIUM OXIDES
HEAVY NUCLEI
HEAVY WATER MODERATED REACTORS
HWLWR TYPE REACTORS
ISOTOPES
MATERIALS
NEUTRON ABSORBERS
NUCLEAR POISONS
NUCLEI
OXIDES
OXYGEN COMPOUNDS
PLUTONIUM 239
PLUTONIUM 241
PLUTONIUM ISOTOPES
RADIOISOTOPES
RARE EARTH COMPOUNDS
REACTIVITY COEFFICIENTS
REACTOR MATERIALS
REACTORS
SORPTION
SPONTANEOUS FISSION RADIOISOTOPES
URANIUM COMPOUNDS
URANIUM DIOXIDE
URANIUM OXIDES
VOID COEFFICIENT
W CODES
WATER COOLED REACTORS
YEARS LIVING RADIOISOTOPES