“…Applying the iterative method to data from ANL-81-27 (Mecham et al 1981, Table 2) yields an RF of approximately 4.83 x lo-' with a cut-off diameter (maximum respirable diameter) of 4.95 pm. The AED method determines an RF of 2.41 x lo-'.…”
Section: Verification Of F S Methodsmentioning
confidence: 99%
“…For UO2, the value of the empirical correlation is based on two experimental data points from single energy density (1.2 J/cm3) impaction tests on three unconfined UOz pellets (Mecham et al 1981, Table 2 and pp. 30 to 35).…”
“…The only data considered in this analysis that have a standard deviation greater than 4.5 is the pulverization data for brittle materials (Mecham et al 1981;Jardine et al 1982). These data are not used in the calculation of the RFs for commercial SNF or crud aerosols.…”
Section: Size Of Respirable Particulatementioning
confidence: 99%
“…The deviation at the end of the spectrum (Le., for larger particles) is attributed to: (1) uneven stresses in the impacted specimens with impact energy being absorbed in highly stressed zones, leaving the low-stressed zones nearly intact and (2) gross discontinuities at the grain boundaries allowing for a lot of energy to be absorbed and only creating microcracks (Mecham et al 1981…”
Section: The Number Distribution Function Is Given By (Dennis 1976 Pmentioning
confidence: 99%
“…These tests characterized the size distribution and the RF of the fragments generated (Mecham et al 1981;Jardine et al 1982).…”
“…Applying the iterative method to data from ANL-81-27 (Mecham et al 1981, Table 2) yields an RF of approximately 4.83 x lo-' with a cut-off diameter (maximum respirable diameter) of 4.95 pm. The AED method determines an RF of 2.41 x lo-'.…”
Section: Verification Of F S Methodsmentioning
confidence: 99%
“…For UO2, the value of the empirical correlation is based on two experimental data points from single energy density (1.2 J/cm3) impaction tests on three unconfined UOz pellets (Mecham et al 1981, Table 2 and pp. 30 to 35).…”
“…The only data considered in this analysis that have a standard deviation greater than 4.5 is the pulverization data for brittle materials (Mecham et al 1981;Jardine et al 1982). These data are not used in the calculation of the RFs for commercial SNF or crud aerosols.…”
Section: Size Of Respirable Particulatementioning
confidence: 99%
“…The deviation at the end of the spectrum (Le., for larger particles) is attributed to: (1) uneven stresses in the impacted specimens with impact energy being absorbed in highly stressed zones, leaving the low-stressed zones nearly intact and (2) gross discontinuities at the grain boundaries allowing for a lot of energy to be absorbed and only creating microcracks (Mecham et al 1981…”
Section: The Number Distribution Function Is Given By (Dennis 1976 Pmentioning
confidence: 99%
“…These tests characterized the size distribution and the RF of the fragments generated (Mecham et al 1981;Jardine et al 1982).…”
Standardized comparative drop weight impact tests were conducted on solid alternative waste forms under consideration for immobilizing Savannah River Laboratory (SRL) defense wastes. The fragment size distributions were measured in the size ranges of ֮5 to 8000 μm. All waste form fragment size distributions could be described accurately by lognormal plots. Respirable sizes (≤10 μm) were measured. Borosilicate glass and SYNROC specimens yielded the same mass fractions of respirable sizes; FUETAP concrete, high silica and alkoxide glass specimens yielded ֮2–3 times more mass fractions of particles of respirable sizes, whereas tailored (Spinel) ceramic specimens yielded the smallest mass fractions of respirable sizes, ֮2–1/2 times less.
A general method for characterizing the major practical effects of accidental impacts on waste packages and for evaluation of scale-model tests has been partially developed. Impact fracture of brittle waste forms has been shown elsewhere to produce particulates whose size distributions are described by the lognormal probability distribution.The model proposed for fragment generation involves the transformation of impact (kinetic) energy into elastic strain energy which is followed by fracture and energy dissipation into heat by the fracture particulates.The peak stresses developing during compressions are approximated as a function of time using elastic theory for a wide range of practical impact conditions for typical (glass) waste forms.The proposed methodology requires experimental validation in terms of correlation of stress and energy parameters with particulate parameters describing the results of fracture. Two kinds of preliminary correlations are presented:(1) calculations of stress parameters for a range of impact conditions; and (2) averages of particulate parameters obtained in standard impact tests.
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