Occupational Intakes of Radionuclides Part 4

Draft document: Occupational Intakes of Radionuclides Part 4
Submitted by Mark Peace, Sellafield Ltd
Commenting on behalf of the organisation

Line 5652 (Fig 18.4) Initial Blood compartment is not shown

Line 5652 (Fig 18.4) is missing arrows from Blood1 to cortical and trabecular volume compartments. (Transfer rates are given in table 18.6.)
Lines 5648 and 5652 (Figs 18.3 and 18.4).  It would be better if the same naming terminology could be used for kidney compartments in both models given that the intention is presumably that they directly map to each other when modelling progeny.

Line 5809 (Table 18.6) Is transfer from Cortical volume to cortical surface an error?  Should it be to cortical marrow instead?
Lines 5935-5959 (identifying equivalent compartments in decay chains).  There are a few cases that aren''t clear to me:
1. For plutonium as a progeny, which blood compartment does activity initially enter?  (My guess is blood1, with blood2 initially being empty, but I don''t think it says.)
2. For Pu241 to Am241 decay, what happens to Am241 produced in Liver0, because there is no Liver0 compartment in the Am model.  (This paragraph seems to imply it should transfer to blood, but liver1 or liver2 would seem more sensible.)
3a. For Pu241 to Am241 decay (for example) I fail to see any reason for modelling the skin and spleen separately.  Neither the Pu or Am models do this so why would it be done as part of a decay chain?  Should it instead say that the spleen and skin are separately modelled if required by any of the progeny in the chain?  Or if it is just done for consistency with other progeny modelling, should it also be done with the parent radionuclide models?
3b. Is the intention that spleen/skin be modelled throughout the chain (ie. including the parent radionuclide)?  The paragraph reads as if the modified model only applies to progeny, but if so how is progeny activity initially allocated to the spleen/skin compartments?
3c. So in summary, for the Pu241+Am241 example, do we:
i) ignore the paragraph about modelling spleen/skin separately
ii) model spleen/skin separately for both radionuclides
iii) model spleen/skin separately for Am241 progeny only, with no initial deposition of Am241 in spleen/skin
iv) model spleen/skin separately for Am241 progency with a fraction of the ST1 decays apportioned to spleen/skin
v) something else
3d. I appreciate it too late to change, but wouldn''t it have made more sense just to specifically model spleen and skin in all the actinide models?

Line 9108 (absorption parameters for Pu238 dioxide).  Para 148 of OIR part 1 requires the use of fr to calculate fA for radioactive prgency produced in the respiratory/alimentary tract following inhalation.  How is this to be applied when the alternative representation is being used and fr is not specified?  (I appreciate that there is no practical need to model the progeny of Pu238, but there may other cases where it does matter.)