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Title: Residual activation of thin accelerator components

Abstract

A method to calculate residual activation of thin accelerator components is presented. A model for residual dose estimation for thick objects made of arbitrary composite materials for arbitrary irradiation and cooling times is employed in this study. A scaling procedure is described to apply the model to thin objects with linear dimensions less than a fraction of a nuclear interaction length. The scaling has been performed for various materials and corresponding factors have been determined for objects of certain shapes (slab, solid and hollow cylinder) which are important from practical standpoint and can serve as models for beam pipes, magnets and collimators. Both contact residual dose and dose attenuation in air outside the objects were considered. A comparison between calculations and measurements performed at the Fermi National Accelerator Laboratory using a 120 GeV proton beam is presented.

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
892321
Report Number(s):
FERMILAB-FN-0788-AD
TRN: US0701078
DOE Contract Number:
AC02-76CH03000
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; 36 MATERIALS SCIENCE; ACCELERATORS; AIR; ATTENUATION; COLLIMATORS; COMPOSITE MATERIALS; COOLING TIME; DIMENSIONS; FERMILAB ACCELERATOR; IRRADIATION; MAGNETS; PROTON BEAMS; Accelerators

Citation Formats

Mokhov, N.V., /Fermilab, Rakhno, E.I., /North Central Coll., Rakhno, I.L., and /Fermilab. Residual activation of thin accelerator components. United States: N. p., 2006. Web. doi:10.2172/892321.
Mokhov, N.V., /Fermilab, Rakhno, E.I., /North Central Coll., Rakhno, I.L., & /Fermilab. Residual activation of thin accelerator components. United States. doi:10.2172/892321.
Mokhov, N.V., /Fermilab, Rakhno, E.I., /North Central Coll., Rakhno, I.L., and /Fermilab. Mon . "Residual activation of thin accelerator components". United States. doi:10.2172/892321. https://www.osti.gov/servlets/purl/892321.
@article{osti_892321,
title = {Residual activation of thin accelerator components},
author = {Mokhov, N.V. and /Fermilab and Rakhno, E.I. and /North Central Coll. and Rakhno, I.L. and /Fermilab},
abstractNote = {A method to calculate residual activation of thin accelerator components is presented. A model for residual dose estimation for thick objects made of arbitrary composite materials for arbitrary irradiation and cooling times is employed in this study. A scaling procedure is described to apply the model to thin objects with linear dimensions less than a fraction of a nuclear interaction length. The scaling has been performed for various materials and corresponding factors have been determined for objects of certain shapes (slab, solid and hollow cylinder) which are important from practical standpoint and can serve as models for beam pipes, magnets and collimators. Both contact residual dose and dose attenuation in air outside the objects were considered. A comparison between calculations and measurements performed at the Fermi National Accelerator Laboratory using a 120 GeV proton beam is presented.},
doi = {10.2172/892321},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon May 01 00:00:00 EDT 2006},
month = {Mon May 01 00:00:00 EDT 2006}
}

Technical Report:

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  • A method to calculate residual activation of accelerator components is presented. A model for residual dose estimation for thick objects made of arbitrary composite materials for arbitrary irradiation and cooling times is employed in this study. A scaling procedure is described to apply the model to thin objects with linear dimensions less than a fraction of a nuclear interaction length. The scaling has been performed for various materials and corresponding factors have been determined for objects of certain shapes (slab, solid and hollow cylinder) that can serve as models for beam pipes, magnets and collimators. Both contact residual dose andmore » dose attenuation in the air outside irradiated objects are considered. A relation between continuous and impulse irradiation is accounted for as well.« less
  • The development and application of an influence function method for calculating stress intensity factors and residual fatigue life for two- and three-dimensional structures with complex stress fields and geometries are reviewed. Through elastic superposition, the method properly accounts for redistribution of stress as the crack grows through the structure. The analytical methods utilized and the computer programs necessary for computation and application of load independent influence functions (IE) are presented. A new exact solution is obtained for the buried elliptical crack, under an arbitrary Mode I stress field for stress intensity factors at four positions around the crack front. Themore » IF method is then applied to two fracture mechanics problems with complex stress fields and geometries. These problems are of current interest to the electric power generating industry and include the fatigue analysis of a crack in a pipe weld under nominal and residual stresses and fatigue analysis of a reactor vessel nozzle corner crack under a complex bivariate stress field.« less
  • 'The proposed research will provide a scientific basis for predicting the long-term fate of radionuclides remaining with the sludge in decommissioned waste tanks. Nuclear activities in the United States and elsewhere produce substantial volumes of highly radioactive semi-liquid slurries that traditionally are stored in large underground tanks while final waste disposal strategies are established. Although most of this waste will eventually be reprocessed a contaminated structure will remain which must either be removed or decommissioned in place. To accrue the substantial savings associated with in-place disposal will require a performance assessment which, in turn, means predicting the leach behavior ofmore » the radionuclides associated with the residual sludges. The phase chemistry of these materials is poorly known so a credible source term cannot presently be formulated. Further, handling of actual radioactive sludges is exceedingly cumbersome and expensive. This proposal is directed at: (1) developing synthetic nonradioactive sludges that match wastes produced by the various fuel processing steps, (2) monitoring the changes in phase chemistry of these sludges as they age, and (3) relating the mobility of trace amounts of radionuclides (or surrogates) in the sludge to the phase changes in the aging wastes. This report summarizes work carried out during the first year of a three year project. A prerequisite to performing a meaningful study was to learn in considerable detail about the chemistry of waste streams produced by fuel reprocessing. At Hanford this is not a simple task since over the last five decades four different reprocessing schemes were used: the early BiPO{sup 4} separation for just Pu, the U recovery activity to further treat wastes left by the BiPO{sup 4} activities, the REDOX process and most recently, the PUREX processes. Savannah River fuel reprocessing started later and only PUREX wastes were generated. It is the working premise of this proposal that most of the phase chemistry in the wastes was defined when the acidic process fluids were first neutralized prior to storage. The only notable exception being that some silicates obviously formed later under highly caustic conditions. Waste stream chemistries for each process have been established and surrogate sludges prepared. Aging of these different recipes have begun at 25, 60, and 90 C and the phase chemistry of the different mixes is being monitored.'« less