| Dose
Limits
Federal
and State
Authorities establish
legal dose limits that an
employee should not exceed in a calendar year.
Administratively,
ISU establishes more conservative values than allowed by Federal and
State authorities and the ALARA goals
(explained
in the next section) are set and self imposed by the ISU Radiation
Safety Committee in
order
to minimize personnel exposure.
The
Idaho State University's
Administrative Occupational
Dose Limits (legal limits set by ISU) are
as follows:
The annual adult
occupational
dose limit
is the more limited of:
- The
total effective
dose
equivalent being
equal to 2,000 mrem (2 rem); or
- The
sum of the
deep-dose
equivalent and the
committed dose equivalent to any individual organ or tissue, being
equal to 10,000 mrem (10
rem).
ISU's
administrative occupational dose limits
are far less
than the occupational dose limits set by the NRC or the State of Idaho.
Idaho
State University's
ALARA Goals
The ALARA goals
are included
here as a
comparison to the legal limits. The ALARA concept is
explained in
the next section.
All
Radiation Safety
Programs:
- 1000
mrem/calendar
year
- 300 mrem/calendar
quarter (notification level)
NRC
Occupational Annual
Dose Limits (applies
to radioactive materials users)
The annual adult
(persons 18
years of
age or older) occupational dose limit established by the United States
Nuclear Regulatory Commission is the more limiting of:
- The
total effective
dose
equivalent being
equal to 5,000 mrem (5 rem); or
- The sum of the deep-dose
equivalent and the committed dose equivalent to any
individual organ or tissue other than the lens of the eye being equal
to 50,000 mrem (50 rem).
- An
eye dose equivalent
of
15,000 mrem (15
rem), and
- A
shallow dose
equivalent
of 50,000 mrem (50
rem) to the skin or to each of the extremities.
Idaho
Quarterly
Occupational Dose
Limits (applies to X-ray and accelerator users only)
- Whole
body; head and
trunk; active blood-forming
organs; lens of eye or gonads 1,250 mrem/cal qtr
- Hands
and forearms;
feet
and ankles 18,750
mrem/cal qtr
- Skin
of whole body
7,500
mrem/cal qtr
General
Public Dose Limits
The dose limit
for members of
the general
public, including all persons who are not classified as radiation
users,
is a total effective dose equivalent not to exceed 100 mrem per
year.
In addition, the dose in any unrestricted area from external sources
cannot
exceed 2 mrem in any one hour.
Fetal
Dose
The embryo-fetus
may be more
susceptible
to radiation effects than an adult and is, therefore, subject to a
lower
dose limit. The dose limit for the embryo-fetus is 500 mrem
(5
mSv)
during the entire gestation period. As a further precaution,
this
limit should not be experienced in an acute fashion, but rather
distributed relatively uniformly during the gestation period if it is
to be experienced (Regulatory
Guide 8.13). This degree of protection for the embryo-fetus
can
only
be achieved with the cooperation of the employee. It is recommended
that she notifies her
supervisor or the RSO as soon as the pregnancy is known. In
order
for
a pregnant worker to take advantage of the lower exposure limit and
dose
monitoring provisions, the woman may declare
her
pregnancy in writing to the TSO. A form letter
can be
obtained
from TSO or by clicking here.
This notification is optional, and at the discretion of the employee
the TSO encourages the act of notification, when appropriate. Unless
a woman declares her pregnancy, ISU can not set special dose equivalent
limits
for her.
Dose
Limits for Minors
The dose limits
for minors
(persons under
18 years of age) are 10% of the adult occupational dose limits.
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