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 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 …”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 Non-Ionizing Radiation

Non-Ionizing Radiation from High to Low Frequency

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 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? 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 Technicium-99m) last only a few days

Some Isotopes & Their Half Lives ISOTOPE ½ Life APPLICATIONS Uraniumbillions of years Natural uranium is comprised of several different isotopes. When enriched in the isotope of U-235, it’s used to power nuclear reactor or nuclear weapons. Carbon y Found in nature from cosmic interactions, used to “carbon date” items and as radiolabel for detection of tumors. Cesium y Blood irradiators, tumor treatment through external exposure. Also used for industrial radiography. Hydrogen yLabeling biological tracers. Irridium dImplants or "seeds" for treatment of cancer. Also used for industrial radiography. Molybdenum hParent for Tc-99m generator. Technicium- 99m 6 hBrain, heart, liver (gastoenterology), lungs, bones, thyroid, and kidney imaging, regional cerebral blood flow, etc..

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-60 has the same activity as 1800 tons of natural Uranium

+ + + Nucleus Neutrons Protons Electrons (Electron Clouds) Structure of the Atom

 Decay He Nucleus Ejected from Nucleus  has a discrete energy that can be measured and related to the parent Most of the energy associated with 

 Decay 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 + antineutrino - neutrino Three products share energy – therefore beta has a continuous range of energies

 Decay 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 neutrino Gamma Photon

Shielding for ,  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 Causes breaks in one or both DNA strands or; Causes Free Radical formation

Cellular Effects

3Cellular Effects Cell death Cell repair Cell change Is this change good or bad?

Dividing Cells are the Most Radiosensitive 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 1/10 th of the annual adult limit)

At HIGH Doses, We KNOW Radiation Causes Harm 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 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 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 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 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

Effects of ACUTE Exposures Dose (Rads*) Effects First sign of physical effects (drop in white blood cell count) 100 Threshold for vomiting (within a few hours of exposure) ~ 50% die within 60 days (with minimal supportive care) ~50 % die within 60 days (with supportive medical care) 1,000 ~ 100% die within 30 days *

Annual Dose Limits External/Internal Exposure Limits for Occupationally Exposed Individuals Adult ( $18 yrs) Minor (< 18 yrs) Whole body*5000 mrem/yr500 mrem/yr Lens of eye15000 mrem/yr1500 mrem/yr Extremities50000 mrem/yr5000 mrem/yr Skin50000 mrem/yr5000 mrem/yr Organ50000 mrem/yr5000 mrem/yr *Effective dose equivalent

Typical Doses Average Dose to US Public from All sources360 mrem/year Average Dose to US Public From Natural Sources300 mrem/year Average Dose to US Public From Medical Uses53 mrem/year Coal Burning Power Plant0.2 mrem/year Average dose to US Public from Weapons Fallout< 1 mrem/year Average Dose to US Public From Nuclear Power< 0.1 mrem/year Occupational Dose Limit for Radiation Workers5,000 mrem/yr Coast to coast Airplane roundtrip5 mrem Chest X ray8 mrem Dental X ray10 mrem Head/neck X ray20 mrem Shoe Fitting Fluoroscope (not in use now)170 mrem CT (head and body)1,100 mrem Therapeutic thyroid treatment (dose to the whole body)7,000 mrem

Radiation is a type of energy; Contamination is material 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 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 Rad orders may be ed, 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 Free shipments must be approved Inter-Laboratory Transfers must Be approved

Incoming Shipments 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 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 Record the Results Wipe tests must be done monthly if you have inventory on hand

Spill Response 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 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.

The Workstation Should NOT Present an Exposure Hazard to Other Individuals

Radiation Protection Decrease Time Increase Distance Increase Shielding

Reduce Waste Volume Exercise care in handling—avoid spills Use counter covers with overlays or cutouts Keep primary rinse volumes to the minimum necessary

Something Extra Irradiating Food Radon Dirty Bombs

What should you remember? 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