Rates and respirable fractions

U.S. Department of Energy (DOE), 1994d, Release Fractions/Rates and Respirable Fractions for Nonreactor Nuclear Facilities, DOE-HDBK-3010-94, U.S. Department of Energy, Washington D.C., December 1994. 

DOE-HDBK-3010 Airborne Release Fractions (ARFs)/Rates and Respirable Fractions (RFs) for Nonreactor Nuclear Facilities... 

DOE-HDBK-3010, Airborne release fractions/rates and respirable fractions for nonreactor nuclear facilities. Document is available from Department of Energy, AD-631 /FORS, Washington, DC. 

Mishima, J., 1993, Recommended Values and Tedmical Bases for Airborne Relea.se Fractions (ARFs), Airborne Release Rates (ARRs), and Respirable Fractions (RFs) for Materials from Accidents in DOE Fuel Cycle, Ex-Reactor Facilities, Revision 2, Draft DOE report, April. 

Here, V is the averaging volume and VB(t) is the volume of phase B within the averaging volume. The parameters sA and eB are the volume fractions of the phases A (eA = VA/V) and B (eB = VB/V), respectively. The parameter Dje is the effective diffusivity tensor of component Ji max e is the maximum reaction rate, and r/n is the first-order endogenous respiration rate coefficient. The cell mass per unit volume of biofilm is defined by... 

Relative to the DOC content, the fractions of higher molecular weight contained more proteinaceous matter than fractions with lower apparent molecular weights (i.e., 10,000 daltons). It is interesting to note that the distribution patterns of the proteinaceous matter showed a reduction of the mean toncentrations of the two smaller fractions which contained most of the tolored substances within the thermocline. This is probably due to the spe- ific productivity and respiration rates in the thermocline. The major frac-ons of DOC seem to be more refractory. 

The method by Wells and Alexander uses lower air velocities (the extraction rate is only 50 litres/minute) and does not, therefore, require a deflector plate. The method does not necessarily release all of the potentially airborne particles in the sample in fact, the dust release may be constant in many repeated pourings of the same sample. Either total airborne dust samples may be collected on a filter (i.e. all particles that are still airborne on leaving the box, i.e. smaller than about 10 microns) or only the respirable fraction may be collected by extraction through the Hexhlet sampler. 

In the test, the drum is loaded with a 100 g sample and rotated at 30 rpm for one minute. The sampling rate is 28.3 litres/minute and the sampling time once again depends on the dustiness of the material, bearing in mind that the impactor must not be overloaded. This apparatus also measures only the respirable fraction of the dust less than about 9 microns and is capable of determining the dust emission curves or just an overall emission rate of dust finer (or coarser) than 9 micron. 

Figures 15.4, 15.5 and 15.6 show the simulated changes in the soil-plant system during 4.1-million-year soil development. The model results are compared with observed data from the LSAG sites with a focus on plant production, inorganic phosphorus fractions, soil organic carbon, nitrogen and phosphorus, nutrient mineralization rates, soil respiration, nitrogen and phosphorus losses, and live leaf nutrient ratios. A key assumption in the model run is that climate remained constant during the 4.1-million-year simulation in fact the...

Depending on the plutonium compound, it may be either soluble or insoluble. Plutonium as the citrate or nitrate was more soluble than the dioxide compound. Plutonium dioxides prepared at temperatures of 700°C or higher had a slower absorption rate compared to air-oxidized forms (Sanders and Mahaffey 1979). The absorption of plutonium was also dependent upon its respirable fraction, or that fraction of the total concentration of plutonium which may deposit in the nonciliated part of the lung. The respirable fraction of plutonium is composed of particles less than 10 om Activity Median Aerodynamic- Diameter (AMAD), which indicates that only particles less than 10 om AMAD would be retained in the nonciliated part of the lung and would be available for absorption (NEA/OECD 1981 Volchoketal. 1974). 

The primary route of exposure to radon and its progeny is inhalation. The degree of deposition and the subsequent absorption of inhaled radon and progeny is determined by physiological parameters, such as respiration rate and tidal volume and physical properties, such as the particle size distribution of the carrier aerosols and of the unattached fraction, the equilibrium state, and solubility coefficients (Crawford-Brown 1987 Holleman et al. 1969 Jacobi 1964). 

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