Thus D0 = fyWZQF
M
D= 0.3 x 1.4 x 1073 x 5 x 7.9 x 103 x 1.0
2UUU
D = 3.3 x 1079 rem = 0.003 rem
TpCi/d) Intake
The 299Sr dose calculated for children from 1 thru 30 years of age is
very similiar to, but a bit less than, the integral 30 year dose calcualted
for adults. Because bone marrow is considered a blood-forming organ (annual
dose limit equals 500 mrem/y) and endosteal cells are in the other organ
category (annual dose limit ggua}s 1500 mrem/y), the bone marrow is the more
sensitive organ in bone for
7“Sr 9),
.
7.3
Transuranic Radionuclides Methodology
The inhalation model used for the Yan dgus isotopes of plutonium and for
24am is that of the ICRP Task Group 23,30) parameters for the lung
model are also those of the ICRP. Both 24!am and plutonium are assumed to
be class-W compounds.
For the ingestion pathway, 55 gut transfer coefficients are 1074 for
plutonium and 5x1074 for @4lam(3t).”
The critical organs are bone and
liver with a biological half-life of 100 y in bone and 40 y in liver.
Of the
plutonium and @4lam transferred to blood, 45% is assumed to reach the bone
and 45% is assumed to reach the liver.
The remaining 10% is distributed among
other organs. A quality factor of 20 is used for both Am and Pu in all dose
calculations.
The 239+240py dose to bone marrow and endgs tea sells is calculated by
Spiers' method in a manner analagous to 90Sr(20, 32,33).
First, a dose to
bone mass Dg is determined based on the concentration in pCi/g. Second, the
ratios D,/Dg and D,/Dg are applied to find the specific doses to the
tissues of interest.
The Dg is related to Dy by
where Sy and Sg are the stopping powers for tissue and bone respectively.
St/Sg =. 1.225
Dp
=
0.2636 (mrad/d * pCi + g)
Dn/Dg = 0.26
Os/Dg = 3.11
|
:
Thus, the ratio for endosteal cell dose to bone marrow dose is
3.11/0.26 = 12.
The conversion for red marrow for Pu from Spiers approach is
338 rem/uCi-y where the Pu is distributed in a 5Kg bone mass and the quality
factor is 20. Thus the conversion for endosteal celis (surface cells) is
4056 rem/uCi-y. The integral 30-y dose conversion factor listed in Table 6
is developed from the above models, parameters and conversion factors.
S001 14
D-9