BLOCK 7: IONIZING RADIATION - Unit 7: Ionizing Radiation Hazard Controls (complete *) Flashcards
According to the Nuclear Regulatory Commission (NRC), people who may receive a higher than average annual dose of radiation are those who:
- live at higher elevations
- travel more by airplane
- smoke
- live by coal power power plants
- undergo more medical treatments involving radiation
- live and work in buildings that
were constructed with materials containing higher concentrations of isotopes
Ionizing radiation regulatory requirements and protection standards are established to keep
exposures ______.
As low as reasonably achievable (ALARA)
What are the 4 categories of annual peacetime dose limits?
- Occupational
- Declared pregnant individuals
- Minors (16-17 years old)
- General public
“the dose received by an individual in the course of employment in which the individual’s assigned duties involve exposure to radiation or to [radioactive material] from regulated and unregulated sources of radiation, whether in the possession of the licensee or other person”
Occupational dose.
- does not include doses received from background radiation
What is the annual dose limit for an occupational worker?
5 rem in a single year or 50 rem to any tissue except the lens of the eye
A ______ is defined as a military or civilian worker who has “informed their workplace supervisor or primary care manager, in writing, of [the] pregnancy and the estimated date of conception”
Declared pregnant individual
What is the dose limit for a declared pregnant individual?
500 mrem to the embryo/fetus for the remainder of the pregnancy and no more than 50 mrem in each month of the pregnancy.
- think about the fact that a fetus has young, rapidly growing, and undifferentiated cells that make it especially susceptible to the effects of radiation exposure.
In regard to ______, AFMAN 48-148 states: “No person under the age of 16 years shall be subjected to occupational exposure, and no person under the age of 18 shall
be allowed to work in a restricted area unless supervised, and then only for the purposes of
training.”
Minors (16-17 years old)
What is the dose limit for minors?
500 mrem/yr and 5 rem to any tissue except the lens of the
eye
Any individual except when that individual is receiving an occupational dose is considered, by AFMAN 48-148, to be a member of the ______.
General Public
What is the dose limit for the general public?
100 mrem/yr
During ______, dose limits vary due to critical tasks and life-saving missions.
Wartime and Radiological Response
*the incident commander establishes these dose limits base on recommendations made by Bioenvironmental Engineering
During wartime and radiological response, total accumulated dose should not exceed
125 rad, per AFMAN 48-148 and
NATO STANAG 2083
What are 3 important considerations when trying to control ionizing radiation?
- Type of radiation
- Energy level
- Route of exposure (internal vs. external)
What are the 5 different types of ionizing radiation?
- Alpha
- Beta
- Gamma
- X-ray
- Neutron
- each has the capacity to penetrate different levels of tissue
What directly effects the penetrating ability of each particular type of ionizing radiation?
Its energy level
*the more energy the radiation has, the greater the biological effect
What are the routes of ionizing radiation exposure?
Internal and external
What are the 3 principle methods by which ionizing radiation is controlled?
- Time
- Distance
- Shielding
Radiation dose (total exposure) is directly proportional to the _____.
time spent in a radiation field.
Dose = exposure rate (mR/hr) x time (t)
Exposure rate is is inversely proportional to the ______.
distance (D) from a point source of radiation.
*EASIEST control method
______ is an engineering control that provides a physical barrier to absorb the energy from the
radiation. It is only effective when thick enough to adequately absorb the type of
radiation present
Shielding
Minimum level of shielding needed to absorb alpha
radiation particles.
Paper
*human skin is also effective
Minimum level of
shielding needed to shield beta radiation.
Sheet of plastic or wood
Gamma and x-rays can be shielded by _____.
Thick layers of concrete or, at minimum, lead
