Criticality experiments with low enriched UO/sub 2/ fuel rods in water containing dissolved gadolinium

Technical Report · Wed Feb 01 00:00:00 EST 1984

DOI:https://doi.org/10.2172/5319210· OSTI ID:5319210

Bierman, S R; Murphy, E S; Clayton, E D; Keay, R T

The results obtained in a criticality experiments program performed for British Nuclear Fuels, Ltd. (BNFL) under contract with the United States Department of Energy (USDOE) are presented in this report along with a complete description of the experiments. The experiments involved low enriched UO/sub 2/ and PuO/sub 2/-UO/sub 2/ fuel rods in water containing dissolved gadolinium, and are in direct support of BNFL plans to use soluble compounds of the neutron poison gadolinium as a primary criticality safeguard in the reprocessing of low enriched nuclear fuels. The experiments were designed primarily to provide data for validating a calculation method being developed for BNFL design and safety assessments, and to obtain data for the use of gadolinium as a neutron poison in nuclear chemical plant operations - particularly fuel dissolution. The experiments program covers a wide range of neutron moderation (near optimum to very under-moderated) and a wide range of gadolinium concentration (zero to about 2.5 g Gd/l). The measurements provide critical and subcritical k/sub eff/ data (1 greater than or equal to k/sub eff/ greater than or equal to 0.87) on fuel-water assemblies of UO/sub 2/ rods at two enrichments (2.35 wt % and 4.31 wt % /sup 235/U) and on mixed fuel-water assemblies of UO/sub 2/ and PuO/sub 2/-UO/sub 2/ rods containing 4.31 wt % /sup 235/U and 2 wt % PuO/sub 2/ in natural UO/sub 2/ respectively. Critical size of the lattices was determined with water containing no gadolinium and with water containing dissolved gadolinium nitrate. Pulsed neutron source measurements were performed to determine subcritical k/sub eff/ values as additional amounts of gadolinium were successively dissolved in the water of each critical assembly. Fission rate measurements in /sup 235/U using solid state track recorders were made in each of the three unpoisoned critical assemblies, and in the near-optimum moderated and the close-packed poisoned assemblies of this fuel.

• Research Organization: Pacific Northwest Lab., Richland, WA (USA)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA), Nuclear Criticality Safety Program (NCSP)
• DOE Contract Number: AC06-76RL01830
• OSTI ID: 5319210
• Report Number(s): PNL-4976; ON: DE84007968
• Country of Publication: United States
• Language: English

Related Subjects

050800* -- Nuclear Fuels-- Spent Fuels Reprocessing
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
ACTINIDE COMPOUNDS
ACTINIDE ISOTOPES
ACTINIDE NUCLEI
ACTINIDES
ALPHA DECAY RADIOISOTOPES
BARYON REACTIONS
CHALCOGENIDES
CRITICALITY
DATA
ELEMENTS
ENERGY SOURCES
ENRICHED URANIUM
EVEN-ODD NUCLEI
EXPERIMENTAL DATA
FISSION
FUEL REPROCESSING PLANTS
FUELS
GADOLINIUM
HADRON REACTIONS
HEAVY NUCLEI
HYDROGEN COMPOUNDS
INFORMATION
ISOMERIC TRANSITION ISOTOPES
ISOTOPE ENRICHED MATERIALS
ISOTOPES
MATERIALS
METALS
MINUTES LIVING RADIOISOTOPES
MIXED OXIDE FUELS
NEUTRON REACTIONS
NUCLEAR FACILITIES
NUCLEAR FUELS
NUCLEAR POISONS
NUCLEAR REACTIONS
NUCLEI
NUCLEON REACTIONS
NUMERICAL DATA
Nuclear Criticality Safety Program (NCSP)
OXIDES
OXYGEN COMPOUNDS
PLUTONIUM COMPOUNDS
PLUTONIUM DIOXIDE
PLUTONIUM OXIDES
RADIOISOTOPES
RARE EARTHS
REACTOR MATERIALS
REPROCESSING
SEPARATION PROCESSES
SLIGHTLY ENRICHED URANIUM
SOLID FUELS
SPENT FUELS
TRANSURANIUM COMPOUNDS
URANIUM
URANIUM 235
URANIUM COMPOUNDS
URANIUM DIOXIDE
URANIUM ISOTOPES
URANIUM OXIDES
WATER
YEARS LIVING RADIOISOTOPES