Gamma-ray spectrometric determination of UF/sub 6/ assay with 1 percent precision for international safeguards. Part 1. Product and feed in 1S and 2S sample cylinders

Technical Report · Tue Sep 01 04:00:00 EDT 1981

OSTI ID:6256256

Ricci, E

A rapid gamma-ray spectrometric (non-destructive) method is described which can determine /sup 235/U enrichment with a relative precision of 1 percent (or less) in UF/sub 6/ contained in 1S and 2S bottles. The method is based on counting the 186 keV gamma rays emitted by /sup 235/U using a Pb-collimated Ge(Li) detector. The gamma-ray count rate, corrected for cylinder wall (nickel) attenuation, is converted to /sup 235/U assay by comparison with standards. Measurements of fifty UF/sub 6/ product and feed cylinders reveal the following precisions (i.e., percent relative standard deviations) which correspond to the counting times given in parenthesis: Product - 2S, 0.98 percent (600 sec); Feed - 2S, 0.48 percent (2500 sec); Product - 1S, 0.62 percent (1000 sec); Feed - 1S, 0.73 percent (3000 sec). A 1 percent precision is desired for the attributes verification measurements of the /sup 235/U concentration for UF/sub 6/ in sample cylinders. Such attributes measurements comprise part of a material-balance verification strategy that can be carried out by the International Atomic Energy Agency (IAEA) during safeguards inspections at uranium enrichment facilities. Although the precision of the above results is satisfactory, the average relative differences between gamma-ray and mass-spectrometric determinations for the last two sets of measurements (1S cylinders) have positive biases. Research and development work is underway to understand and correct these biases. Also, a series of measurements of UF/sub 6/ tails in 1S and 2S bottles are currently being performed and evaluated.

• Research Organization: Oak Ridge Gaseous Diffusion Plant, TN (USA)
• DOE Contract Number: W-7405-ENG-26
• OSTI ID: 6256256
• Report Number(s): K/OA-5014-Rev.1; ON: DE81030818
• Country of Publication: United States
• Language: English

Related Subjects

055001 -- Nuclear Fuels-- Safeguards
Inspection
& Accountability-- Technical Aspects
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400103* -- Radiometric & Radiochemical Procedures-- (-1987)
98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL PROTECTION
ACCOUNTING
ACTINIDE COMPOUNDS
ACTINIDE ISOTOPES
ACTINIDE NUCLEI
ALPHA DECAY RADIOISOTOPES
CENTRIFUGE ENRICHMENT PLANTS
CHEMICAL ANALYSIS
COMPARATIVE EVALUATIONS
DATA
EVEN-ODD NUCLEI
EXPERIMENTAL DATA
FLUORIDES
FLUORINE COMPOUNDS
GAMMA SPECTROSCOPY
HALIDES
HALOGEN COMPOUNDS
HEAVY NUCLEI
IAEA SAFEGUARDS
INDUSTRIAL PLANTS
INFORMATION
ISOMERIC TRANSITION ISOTOPES
ISOTOPE RATIO
ISOTOPE SEPARATION PLANTS
ISOTOPES
MANAGEMENT
MASS SPECTROSCOPY
MINUTES LIVING RADIOISOTOPES
NONDESTRUCTIVE ANALYSIS
NUCLEAR FACILITIES
NUCLEAR MATERIALS MANAGEMENT
NUCLEI
NUMERICAL DATA
PORTSMOUTH CENTRIFUGE ENRICHMENT PLANT
QUANTITATIVE CHEMICAL ANALYSIS
RADIOISOTOPES
RELIABILITY
SAFEGUARDS
SPECTROSCOPY
URANIUM 235
URANIUM COMPOUNDS
URANIUM FLUORIDES
URANIUM HEXAFLUORIDE
URANIUM ISOTOPES
YEARS LIVING RADIOISOTOPES