- 51 VIII
.
,
Summary of Recommendations
he following recommendations apply to alpha-emitting
hot particles where a hot particle is defined as a particle
_that contains sufficient activity to deliver at least 1000
rem/yr to the surrounding lung tissue.
For isotopes having
half-lives greater than one year, this would correspond to
particles containing at least 0.07 pCi of alpha activity. °?
It is recommended that:
l.
“Ff
For occupational exposure
MPLPB = 2 hot particles
pos
C
fou
MPC, for Pu-239 = 3.5x10716 uci/m1®®
2.
For non-occupational exposure
MPLPB = 0.2 hot particles
MPCa for Pu-239 = 9x10718 uci/mi®?
.87/ These particulates would consist of compounds of Pu and
the other actnides which fall into Class Y material in tne ICRP
Task Group Lung Moecel.
These materials vrould be retained for
years in the lung.
See for example, ICRP Publication 19, Oc. cit.
‘p. 6.
Since only particles in the size range of 5 u and below
&
=
=
_
88/
“4
jae fue
it
This MPCg applies for particles contai: ng 0.07 pCi of
Pu-239.
For particles containing more than 0.07 pCi the
MPCa could be inercased proportionateiy.
For particles
containing less thar 0.07 pCi the existing MPCa=4él07++ cci/m
would apply.
The MPCa fer hot particles of other isoctovcis
and mixtures of isotores sheuld be established on a similis
basis with consideration given to the half-life of the isctse:.
e9/
Ibid.
ee
uo
ct
qv
here.
If the half-life is less than or close to 1 year the
Of 0.07 pCi can be adjusted upward through appropriate caicu
t-:
BH dnt (0
mM
cr
'
qt
diameter would be Cevosited in the deep respiratory tissue, ¢!
in effect sets an upver limit for the particle size of inter
Je
+ a
— *