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Shuffler bias corrections using calculated count rates.

DE2001782816

Publication Date	2001
Personal Author	Rinard, P.; Hurd, J.; Hsue, F.
Page Count	5
Abstract	Los Alamos National Laboratory has two identical shufflers that have been calibrated with a dozen U3O8 certified standards from 10g 235 U to 3600 g 235 U. The shufflers are used to assay a wide variety of material types for their 235 U contents. When the items differ greatly in chemical composition or shape from the U3O8 standards a bias is introduced because the calibration is not appropriate. Recently a new tool has been created to calculate shuffler count rates accurately, and this has been applied to generate bias correction factors. The tool has also been used to verify the masses and count rates of some uncertified U3O8 standards up to 8.0 kg of 235 U which were used to provisionally extend the calibration beyond the 3.6 kg of 235 U mass when a special need arose. Metallic uranium has significantly different neutronic properties from the U3O8 standards and measured count rates from metals are biased low when the U3O8 calibration is applied. The application of the calculational tool to generate bias corrections for assorted metals will be described. The accuracy of the calculational tool was verified using highly enriched metal disk standards that could be stacked to form cylinders or put into spread arrays.
Keywords	LANL Uranium Assaying Calibration Standards Verification Nondestructive tests Shufflers
Source Agency	Technical Information Center Oak Ridge Tennessee
NTIS Subject Category	77 - Nuclear Science & Technology
Corporate Authors	Los Alamos National Lab., NM.; Department of Energy, Washington, DC.
Document Type	Conference Proceedings
NTIS Issue Number	200210
Contract Number	W-7405-ENG-36

Shuffler bias corrections using calculated count rates.

Shuffler bias corrections using calculated count rates.
DE2001782816

Publication Date	2001
Personal Author	Rinard, P.; Hurd, J.; Hsue, F.
Page Count	5
Abstract	Los Alamos National Laboratory has two identical shufflers that have been calibrated with a dozen U3O8 certified standards from 10g 235 U to 3600 g 235 U. The shufflers are used to assay a wide variety of material types for their 235 U contents. When the items differ greatly in chemical composition or shape from the U3O8 standards a bias is introduced because the calibration is not appropriate. Recently a new tool has been created to calculate shuffler count rates accurately, and this has been applied to generate bias correction factors. The tool has also been used to verify the masses and count rates of some uncertified U3O8 standards up to 8.0 kg of 235 U which were used to provisionally extend the calibration beyond the 3.6 kg of 235 U mass when a special need arose. Metallic uranium has significantly different neutronic properties from the U3O8 standards and measured count rates from metals are biased low when the U3O8 calibration is applied. The application of the calculational tool to generate bias corrections for assorted metals will be described. The accuracy of the calculational tool was verified using highly enriched metal disk standards that could be stacked to form cylinders or put into spread arrays.
Keywords	LANL Uranium Assaying Calibration Standards Verification Nondestructive tests Shufflers
Source Agency	Technical Information Center Oak Ridge Tennessee
NTIS Subject Category	77 - Nuclear Science & Technology
Corporate Authors	Los Alamos National Lab., NM.; Department of Energy, Washington, DC.
Document Type	Conference Proceedings
NTIS Issue Number	200210
Contract Number	W-7405-ENG-36