Radiological Hazards Flashcards
Radiation Types
Ionizing or nonionizing
Both are energy waves
ionizing can exist as particles / non ionizing contains less energy
major types of radiation emitted are , beta particles and gamma rays.
xrays arise from processes outside of the nucleus
non ionizing radiation
includes radiant heat, radio waves ultraviolet radiation and light.
wast site sources of non ionizing radiation microwaves and welding, ultraviolet radiation laser instruments used for measuring and leveling and radio equipment
radiation emitting equipment should be used with proper precautions
ionizing radiation has sufficient energy to remove electrons from atoms.
radiation
Source of radiation
Once source of the radiation is the Nuclei of unstable atoms. radioactive atoms referred to as radioneuclides or radiostopes - to become more stable . The nuclei eject or injset subatomic particles and high energy photons (gamma rays). this process is called radioactive decay. unstable isotopes of radium, radon, uranium and thorium for eg exist naturally.
others are continually bneing made naureally osuch as the splitting of atoms rin a nuclear reactor. releasing ionizing radiation. this decaying is caused by instability within the nucleus of the material.
Ionizing radiation
Ionizing radiation has many uses
xrays, measuring soil density, metals analyzer and
food pastueration
3 types of ionizing radiation are:
alpha
beta
gamma
Types of Radiation
Alpha particles are the largest of the particles emmited from the nucleus of an atom . large size. t
they will quickly collide with an atom and loose their energy. travel only a few cm in the air.
a piece of paper, normal work clothes, or the layer of skin on a body can stop an alpha particle. they are easily stopped. once in the body they are only cm away from organs.
Beta particles - are much smaller in mass than alpha particals and less likely to collide with sorrounding items. can travel much farther.
can penetrate certain materials
thin piece of metal , wood, plastic or glass
health hazard to human skin and organs if ingested or inhaled the cornea of the eye is especially vulnerable and sensitive.
Gamma radiation
the most dangerous of the 3 types
have no mass or chage and are considered pure energy and can travel great distances and interact with living cells
lead, concrete are used to stop gamma waves
nothing that you can wear that will protect a worker from gamma waves. therefore they are at risk anytime there is an exposure.
Radiation Doses and Units
R - rad Roentagen (Radiation absorbed dose)
Rem - (Roentagen Equivalent Man)
Roentagen is defined in terms of the ionizing effect on air and applies only to xrays and gamma rays.
It does not relate to the effect of radiation on the human body. The rad measures the abosorbed dose.
(the amount of ionizing radiation absorbed into a material)
The rad does not take into account the potential effect the different types of radiation have on the body.
The rem is the most commonly used unit of measure and is used for dose equivalence. It takes into effect the different types of biological effects produced by different types of radiation
Sources of radiation exposure
daily the human body must deal with the exposure. at a properly monitored worksite the occupational exposure is a fraction of exposure that the body is already dealing with .
any release of radioactive material is a potential source of radiation exposure to the population.
Radiation Exposure is Measured by a docemeter badge worn by the employee
Dose Rates
radiation units include a time factor Dose rates r/hr or mr/hr (mr/hr = 1/1000) rad/ hr or mrad/hr rem/hr mrem/hr
radiation dosage
use the same terms found in toxicolgy
amount of exposure X duration of exposure (time)
Quantity X Time
acute or chronic
Chronic Dose
Small amounts of radiation over a period of time
the body is able to tolerate a chronic dose over an acute dose.
Chronic Dose
Small amounts of radiation over a long period of time
such as the daily exposures over our lifetimes. the body is able to tolerate a chronic dose over an acute dose.
Acute dose
have a greater effect on us because the body does not have time to repair or replace the damaged body cells.
an acute dose of 10000 to 25000 mrem could cause changes clight blood changes otherwise normal individual would not be interested
Dose Limits
maximum permissible radiation dose equivalent that an individual is allowed to receive. should never be considered
EPA has established 1 mrem per hour
EPA states that investigation and monitoring can continue the As readings increased above background radiation levels.
At the action level of 1 mrem, Area vacated boundary clearly marked and a health personnel employed.
DOE limits should be the same as all regulation s established for all federal agencies by the EPA
Radiation Exposure
explains how a given cell is sensitiee to radiation damage.
the faster a cell reproduces the more sensitive to radition.
the following cells are the most
blood, reproduction organs, sperm or egg, cells of the unborn child, neve, digestive tract cells,
radistion affects each person differently depending on age, medical history and physical and mental condition.
the affects of radiatin may be acute or chronic.
Radiation Exposure
explains how a given cell is sensitive to radiation damage.
the faster a cell reproduces the more sensitive to radiation.
the following cells are the most radiosensitive because of reproductive rate:
blood, blood producing organs, reproduction organs, sperm or egg, cells of the unborn child, neve, digestive tract cells, immature white blood cells,
Nerve muscle and bone cells reproduce slowly
radiation affects each person differently depending on age, medical history and physical and mental condition.
the affects of radiation may be acute or chronic.
Chronic Radiation Exposure
low levels of ionizing radiation over a long period of time.
Possible effects are risks cancer and cataracts
Possible genetic effects sperm and egg cells
Genetic damage birth defects
Exposed workers genetic effects can be
passed ot future generations
is measured in mrem over many days
OSHA 29 CFR 1910.96
Acute radiation exposure
a large dose in a short possible\ time lowering of white blood cell count nausea bacteria infections loss of appetite Reddening of the skin diarrhea fatigue hair loss possible sterility
More severe exposure can cause the following symptoms:
Fever a abdominal pains explosive diarrhea convulsions internal bleeding infection shock convulsions coma and eventually death acute exposure 25 rem/hr over 25 hours
Radioactive contamination
in the form of 3 states of matter
solid
liquid
gas
Solid - dirt small particles such as dust or dirt
liquid - suspended or dissolved
radioactive gasses that have the potention of leaking from storage vessels. can be fixed or can be transferable or smearable.
Fixed Contamination
not easily transferred by one place to another. it is usually fixed by chemical or physical absorbtion or by entrapmemt by irrigularities in the surface material
Transferable Smearable Transmission
Transferable or smearable contamination is easily removed.
any object that makes contact can become contanimated. clean up activities where radioactive dust or dirt is can lead to airborne contamination froms sweeping or bagging
examples of transferable contamination
surface - spread by contact
airborne - air currents grinding burning and evaporation
hot particles which are small pieces of radioactive material with avery high radioactivity level
hot particles can be especially hazardous to the skin or extremeties and the intensity of the radiation emitted.
Radiation protection
radiation must be detected using radiation monitoring instruments
containers should be checked when they are opened
container may be unmarked or unproperly marked
when detected the nuclear regularory commission NRC must be contacted for advice
some states have their own agencey which should be contacted.
When radioactive materials are confirmed
Radioactive material is found
a basic undestanding of protection is required
the radioactive material has become attached to the person’s body and be contaminated clothing or equipment or has entered thr body through the openings in the skin, inhalation,
the best protection against radiation
ALARA - as low as reasonably achievable
the concept requires tasks that are to be performed in a radiologically controlled area and this process in integrated into all activities involving radioactive materials for all parties involved
3 principles
workers can apply 3 principles from ionizing radiation exposure
time
distance
shileding
