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Radiation Safety and Operations. The University of Montana-Missoula. How most of us feel about radiation until we understand the principles of safe use:. Today’s Mixed Message.

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Radiation safety and operations

Radiation Safety and Operations

The University of Montana-Missoula



Today s mixed message
Today’s Mixed Message principles of safe use:

The amount and type of radionuclides used at the University of Montana do not pose undue risk HOWEVER

The Nuclear Regulatory Commission does NOT have a sense of humor


Nrc enforcement policy
NRC Enforcement Policy principles of safe use:

…”Prompt and vigorous enforcement action will be taken when dealing with licensees and their employees who do not achieve the necessary meticulous attention to detail and the high standard of compliance which the NRC expects…”


What are we not talking about at least not much
What are we not talking about? principles of safe use:At least not much

Non-Ionizing Radiation



Radiation and radioactive material are a natural part of our lives
Radiation and Radioactive Material are a Natural Part of Our Lives

  • We are constantly exposed to low levels of radiation from outer space, earth, and the healing arts.

  • Low levels of naturally occurring radioactive material are in our environment, the food we eat, and in many consumer products.

  • Some consumer products also contain small amounts of man-made radioactive material.

Smoke

Detector


Unstable atoms decay
Unstable Atoms Decay Lives

  • The number of “decays” that occur per unit time in the radioactive material tell us how radioactive it is.

    • Units include Curies (Ci), decays per minute (dpm), and Becquerels (decays per second).

  • When an unstable atom decays, it transforms into another atom and releases it’s excess energy in the form of radiation. Radiation can be

    • Electromagnetic radiation (like X or gamma rays), and

    • Particles (like alpha, beta, or neutron radiation)

  • Sometimes the new atom is also unstable, creating a “decay chain”


How unstable is it
How Unstable Is It? Lives

  • The “Half-Life” describes how quickly Radioactive Material decays away with time.It is the time required for half of the unstable atoms to decay.

  • Some Examples Example:

    • Some natural isotopes (like uranium and thorium) have half-lives that are billions of years,


Half life calculation

Most medical isotopes (like LivesTechnicium-99m) last only a few days

Half Life Calculation



The amount of radioactivity is not necessarily related to size
The Amount of Radioactivity is NOT Necessarily Related to Size

  • Specific activity is the amount of radioactivity found in a gram of material.

  • Radioactive material with long half-lives have low specific activity.

    1 gram of Cobalt-60has the sameactivity as1800 tons of natural Uranium


Structure of the Atom Size

Nucleus

Neutrons

+

+

+

Protons

Electrons

(Electron Clouds)


SizeDecay

+

+

+

+

+

+

+

+

+

 has a discrete energy that can be measured and related to the parent

4He Nucleus

Ejected from Nucleus

Most of the energy

associated with 


 Decay Size

antineutrino

+

+

+

+

+

+

+

+

+

+

-

neutrino

Three products share energy – therefore beta has a continuous range of energies

Either too many neutrons or too many protons

Take away + charge and change a proton into a neutron

Take away - charge and change a neutron into a proton


 Decay Size

+

+

+

Gamma Photon

+

+

+

+

+

+

-

neutrino

  • Emission of a photon from the nucleus

  • Often occurs after  or  when nucleus is in an excited state

  • Given off with discrete energies

  • Can measure photon energy and possibly identify parent


Shielding for Size,  and 

BASIC CONCEPT is to:

Place materials between the source and person to absorb some or all of the radiation


Ionizing radiation at the cellular level
Ionizing Radiation at the Cellular Level Size

  • Causes breaks in one or both DNA strands or;

  • Causes Free Radical formation



Cellular effects1
Cellular Effects Size

Cell death

Cell repair

Cell change

Is this change good or bad?


Dividing cells are the most radiosensitive
Dividing Cells are the Most Radiosensitive Size

  • Rapidly dividing cells are more susceptible to radiation damage.

  • Examples of radiosensitive cells are;

    • Blood forming Cells

    • The intestinal lining

    • Hair follicles

    • A fetus

This is why the fetus has a exposure limit (over gestation period) of 500 mrem (or 1/10th of the annual adult limit)


At high doses we know radiation causes harm
At HIGH Doses, We KNOW Radiation Causes Harm Size

  • High Dose effects seen in:

    • Radium dial painters

    • Early radiologists

    • Atomic bomb survivors

    • Populations near Chernobyl

    • Medical treatments

    • Criticality Accidents

  • In addition to radiation sickness, increased cancer rates were also evident from high level exposures.


Us terms
US Terms Size

  • Roentgen-Based on the quantity of electrical charges produced in air by X or Gamma photons 1R=2 billion pr

  • RAD-Radiation Absorbed Dose is the work energy resulting from the absorption of one ROENTGEN or 6.24 E5 Mev


More us terms
More US Terms Size

  • REM-Roentgen Equivalent Mammal is equal to the absorbed does in RADS multiplied by a quality factor

  • Quality Factors

  • Beta = 1

  • Gamma & X ray photons = 1

  • Alpha = 10

  • Neutrons = 20


New terms sort of
New Terms Sizesort of

International Units have replaced the RAD and REM

GRAY (Gy) = 100 RAD

SIEVERT (Sv) = 100 REM

Same Quality Factors apply to the Sv


Units of radioactivity
Units of Radioactivity Size

  • Curie (Ci) = 2.22 E12 dpm or 3.7E10 dps

  • Becquerel (Bq) = 1 dps

  • Maximum Dose/year = 5 REM or 50 mSv

  • Maximum Dose/year for Declared Pregnant Woman & Minors= 0.5 REM or 5 mSv



Annual dose limits

Adult ( Size$18 yrs)

Minor (< 18 yrs)

Whole body*

5000 mrem/yr

500 mrem/yr

Lens of eye

15000 mrem/yr

1500 mrem/yr

Extremities

50000 mrem/yr

5000 mrem/yr

Skin

50000 mrem/yr

5000 mrem/yr

Organ

50000 mrem/yr

5000 mrem/yr

Annual Dose Limits

External/Internal Exposure Limits for Occupationally Exposed Individuals

  • *Effective dose equivalent



Radiation is a type of energy contamination is material
Radiation is a type of energy; Contamination is material Size

  • Exposure to Radiation will not contaminate you or make you radioactive

  • Contamination is Radioactive Material spilled someplace you don’t want it.

  • Radioactive contamination emits radiation

  • Contact with Contamination can contaminate you with the material


Rad use at um
RAD use at UM Size

  • Prior to first use of radionuclides, the Authorized User must provide written and interactive training.

  • Read the Radiation Safety Manual

  • Specific, clear and detailed instruction on safe handling

  • Documentation

  • No Nukes in Designated Areas


Ordering radionuclides
Ordering Radionuclides Size

Rad orders may be emailed, ordered via the web or faxed to EHRM and must include an index code

EHRM will place order and enter charges in Banner for you—This allows us to check inventory totals prior to ordering


What if i don t pay for my nukes
What if I Don’t Pay for my Nukes Size

Free shipments must be approved

Inter-Laboratory Transfers must

Be approved


Incoming shipments
Incoming Shipments Size

  • LOOK FOR DAMAGE OR LEAKAGE

  • Use the appropriate survey meter to confirm the TYPE and AMOUNT of detectable radiation is proper

  • Run a Blank with each time

  • Wipe test outer package and run wipes in LSC

  • Check each inner increment of packaging

  • Record the Results on your inventory sheet in the Rad Manual

  • Notify the RSO if any contamination is found


Security
Security Size

  • All Radioactive Materials must be secured or under direct supervision at all times

  • There MUST be someone in the room at all times OR the door must be locked.


Contamination surveys
Contamination Surveys Size

Record the Results

Wipe tests must be done monthly if you have inventory on hand


Spill response
Spill Response Size

  • On Skin—flush completely

  • On Clothing—remove

  • If Injury—administer first aid

  • Radioactive Gas Release—vacate area, shut off fans, post warning

  • Monitor all persons and define the area of contamination


Alara
ALARA Size

As Low As Reasonably Achievable—means making every reasonable effort to maintain exposures to radiation as far below the dose limits as is practicable consistent with the purpose for which the licensed activity is undertaken, taking into account the state of technology, the economics of improvements in relation to the state of technology, the economics of improvements in relation to benefits to the public health and safety, and other societal and socioeconomic considerations, and in relation to utilization of nuclear energy and licensed materials in the public interest.



Radiation protection
Radiation Protection Other Individuals

  • Decrease Time

  • Increase Distance

  • Increase Shielding


Reduce waste volume
Reduce Waste Volume Other Individuals

  • Exercise care in handling—avoid spills

  • Use counter covers with overlays or cutouts

  • Keep primary rinse volumes to the minimum necessary


Something extra
Something Extra Other Individuals

  • Irradiating Food

  • Radon

  • Dirty Bombs


What should you remember
What should you remember? Other Individuals

  • The NRC has no sense of humor

  • The amount and type of radionuclides used

  • at UM are very unlikely to cause you harm

  • You must abide by all the rules

  • If you have questions make sure they get answered ASAP


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