| Radionuclide
Data
Definitions:
Annual
Limit on Intake (ALI)
-
The quantity of a radionuclide which, if taken into the body, produces
an effective dose equivalent
of 5 rem. Because of differences in physiological transport
mechanisms,
the ALIs vary depending on the route of intake. For purposes
of
contamination
control and bioassay procedures, the most limiting ALI as appropriate for either ingestion or inhalation
is used.
Reference
Quantity (RQ)
- A quantity
of a radionuclide (expressed in microcuries) related to its relative
hazard
potential and used to prescribe requirements for handling, monitoring,
labeling and disposal. Reference quantities are obtained from
10CFR20,
Appendix C.
Removable
Contamination
Limits (RCL)
- A basic limit for removable surface contamination, specified in
"Contamination
Limits and Action Levels" (RPR 10B, based on NRC Reg Guide 8.23).
Dose
Equivalent Rates
(mrem/hour) as given:
Penetrating
- the dose
rate from
photons at 1 meter from a point source of 1 millicurie, assumed to be
proportional
to the inverse of the square of the distance between the point source
and
the receptor.
Skin
dose - dose
rate to the basal
epidermal cells from contamination on the skin, expressed in
microcuries per unit area of skin (microCi/cm2) over an area
of at least
1 cm2.
_____________________________________________________________________________________
Low-energy
beta or
electron emitters with negligible external exposure potential.
|
Nuclide
|
Half Life
|
Reference
Quantity
(microCi)
|
Ingestion ALI (mCi)
|
|
H-3
|
12
years
|
1,000
|
80
|
|
C-14
|
5,730
years
|
100
|
2
|
|
S-35
|
87
days
|
100
|
6
|
|
Cl-36
|
3x105
years
|
10
|
2
|
High-energy beta
emitters
with negligible gamma emission but capable of significant
bremsstrahlung*
production if not properly shielded. Emphasis is on control
of
doses
to extremities and prevention of intake.
|
Nuclide
|
Half Life
|
Reference
Quantity
(microCi)
|
Ingestion ALI (mCi)
|
|
P-32
|
14.3
days
|
10
|
0.6
|
|
Sr-Y-90
|
29.12 years
|
0.1
|
0.03
|
* Bremsstrahlung radiation is electromagnetic radiation emmitted by swiftly moving charged particles as they de-accelerate.
Radioiodines are
treated
as a separate category for exposure evaluation. Emphasis is
on
prevention
of intake by ingestion or inhalation.
|
Nuclide
|
Half Life
|
Reference
Quantity
(microCi)
|
Ingestion ALI (mCi)
|
|
I-125
|
60
days
|
1
|
0.04
|
|
I-129
|
1.57x107
years
|
1
|
0.005
|
|
I-131
|
8
days
|
1
|
0.03
|
Noble gases
present minimal
exposure potential or waste disposal problems.
|
Nuclide
|
Half Life
|
Reference
Quantity
(microCi)
|
Ingestion ALI (mCi)
|
|
Kr-85
|
10.7
years
|
1,000
|
NA
|
|
Xe-133
|
5.2
days
|
1,000
|
NA
|
Naturally
occurring
radionuclides are primarily alpha emitters. Emphasis is on prevention
of intake
by ingestion or inhalation.
|
Nuclide
|
Half Life
|
Reference
Quantity
(microCi)
|
Ingestion ALI (mCi)
|
|
Th-232
|
1.4x1010
years
|
100
|
0.0007
|
|
U-238
|
4.5x109
years
|
100
|
0.02
|
Radionuclides
which emit
gamma rays of substantial energy and with ALI greater than or equal to
1 millicurie; emphasis is on external
exposure control and monitoring.
|
Nuclide
|
Half Life
|
Reference
Quantity
(microCi)
|
Ingestion ALI (mCi)
|
|
Na-24
|
15 hours
|
100
|
4
|
|
Mn-54
|
312
days
|
100
|
2
|
|
Mo-99
|
2.8
days
|
100
|
1
|
|
Tc-99m
|
6 hours
|
1,000
|
80
|
|
Au-198
|
2.7
days
|
100
|
1
|
ALL
OTHER RADIONUCLIDES not
included
in one of the above groups are assumed to have potentials
for
both external and internal exposures and must be evaluated individually.
|
Nuclide
|
Half Life
|
Reference
Quantity
(microCi)
|
Ingestion ALI (mCi)
|
|
Na-22
|
2.6
years
|
10
|
0.4
|
|
Co-60
|
5.27
years
|
1
|
0.2
|
|
Zn-65
|
244
days
|
10
|
0.4
|
|
Ir-192
|
74
days
|
1
|
0.9
|
|
Hg-203
|
47
days
|
100
|
0.5
|
|
