In vivo measurement of Pu dissolution parameters of MOX aerosols and related uncertainties in the values of the dose per unit intake.

The aim of this study was to compare dissolution parameter values for Pu from industrial MOX with different Pu contents. For this purpose, preliminary results obtained after inhalation exposure of rats to MOX containing 2.5% Pu are reported and compared to those obtained previously with MOX containing 5% Pu. Dissolution parameter values appear to increase when the amount of Pu decreases. Rapid fractions, f r , of 4 × 10 -3 (s.d. = 2 × 10 -3 ) and 1 × 10 -3 (s.d. = 6 × 10 -4 ) and slow dissolution rates, s s , of 2 × 10 -4 d -1 (standard deviation, σ = 5 × 10 -5 ) and 5 × 10 -5 d -1 (σ = I × 10 -5 ) were derived for MOX containing 2.5 and 5% of Pu. respectively. Simulations were performed to assess uncertainties on dose due to experimental errors. The relative standard deviations of the dose per unit intake (DPUI) due to f r (4-8%), are far less than those due to s s (shout 20%), which is the main parameter altering the dose. Although quite different dissolution parameter values were derived, similar DPUIs were obtained for MOX aerosols containing 2.5 and 5% Pu which appear close to that for default Type S values.