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Radiation Safety Training Module 2 – Safety and Radiation

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1 Radiation Safety Training Module 2 – Safety and Radiation

2 2003 Chp 1, “Radiation Safety Organization”
Chp 2, “Principles of Radiation Safety”” Chp 3, “Radiation Exposure Limits” Chp 4, “Facilities and Equipment Considerations” Chp 5, “Procurement and Transfer of Radioactive Materials” Chp 6, “Radiological Surveys” Chp 7, “Radiological Postings” Chp 8, “Response to Radiological Incidents” Chp 9, “Laboratory Procedures” Chp 10, “Radioactive Waste Handling and Disposal” Chp 11, “Radiological Improvement Program” 2003 Chp 12, “Radiation Producing Equipment”


4 RAD WASTE CONTAINERS 30 gal. Fiber drum 5 gal plastic 2.5 gal carboy
(CRS ) 30 gal. Fiber drum (CRS ) LINERS! 5 gal plastic bucket

The primary factors associated with RAM storage areas are distance and shielding. No one should spend time around RAM storage areas. Where you place your RAM and RAD waste is essential in keeping doses ALARA If an ideal place is not suitable, then shielding should be implemented. Secondary containment should always be used.





10 “Summary of Isotope Inventory” up to date at all times
Know where your RAM is at all times ! Utilize proper and accurate inventory controls. Keep this form, “Summary of Isotope Inventory” up to date at all times

11 State Requirements for Storage and Control of Licensed or Registered Sources of Radiation
Must be secured to prevent unauthorized removal or access in unrestricted areas. Under Lock and Key is ideal. If not, area access doors locked, or constant surveillance Shall control and maintain constant surveillance if in an unrestricted area.

12 Radioactive Materials Security
.03(10) lists SECURITY requirements Recent incidents in this country and other states have prompted the NRC to increase security requirements All sources of radiation must be secured against theft or use by unauthorized individuals - CHECK SECURITY IN YOUR LAB !!


14 exposure rate in milliRoentgen per hour
Survey Instruments Portable and hand-held Direct, real time and immediate measurements How the survey instrument was calibrated will decide what it is measuring. Look closely at the calibration information. Measure: exposure rate in milliRoentgen per hour mR/hr

15 Selection of a Survey Instrument
What type of radiation does the instrument detect? Some instruments detect more than one type of radiation It is critical to use an instrument appropriate for the radiation of concern Show each instrument and briefly describe each. Do not get into great detail. G-M: can respond to ,  and :  and ; or  only depending on the tube/window wall thickness Thin windowed probes required to pick up weak Betas like C-14

16 Recommended Survey Instrument
Ludlum model 3 instrument (Part No ) with a meter dial and extra cable Explain that we can service these instruments. We will not guarantee service or calibration on any other instruments. Show the instrument and the meter dial.

17 Recommended Survey Probes
Ludlum model 44-9 (Part No ) Alpha, Beta, Gamma pancake probe General Purpose Ludlum model 44-3 (Part No ) Gamma probe Low Energy Gamma (10-60 keV, Iodine) Ludlum model 44-2 (Part No ) Gamma probe High Energy Gamma Show each of these probes. Demonstrate the backgrounds for each. Compare the thin crystal background and take the Am-241 check source and demonstrate that this is what your body might sound like if it was a thin crystal probe. Demonstrate the pancake probe using a mantle lantern. What type of radiation are we seeing? Put a piece of paper over mantle. Does the count rate go down? May not hear the rate decrease, but should see the meter reading decrease. Relate this to detection sensitivities between monitoring clicks and static count. Place alpha probe on paper covered mantle. Remove paper and demonstrate shielding for alphas. Pull alpha probe away from mantle and demonstrate how far alphas go in air and how you can determine if alphas are present using the pancake and distance. Place the pancake back on the mantle and pull away to see how the rate changes with distance. Relate this to the radiation (alpha, beta, gamma). How can we shield for betas? Place a plastic cover over the pancake probe and measure the mantle. The count rate should go down because of the betas being shielded. What effect would placing plastic or parafilm over the probe have? Do we have gammas? Turn the probe over and measure through the back. The count rate should be above background but much lower. These may be gammas, but it may also be bremstrahlung created in the metal backing. Use the Co-60 check source to demonstrate high energy gammas. Use the pancake and the Am-241 check source. Wave the pancake over the source very fast and then slow down to demonstrate survey speed. Use the thin crystal and demonstrate how much more efficient it is at picking up the low energy photon from Am by waving it over the Am-241 source in the same manner as was illustrated with the pancake. Which one would you rather use for low energy photons? Use the thin crystal and measure the Co-60 source and then use the 1x1 NaI to measure the Co-60 source. Discuss the differences between the size of the crystals in the probes and the window on the thin crystal allowing low energy photons to enter easily. The thin crystal does respond to the Co-60.

18 What Can The Instrument Detect?
Can the instrument detect tritium? Can there be contamination that the instrument cannot detect? There is an instrument to detect tritium, but it needs a gas cylinder, a smooth surface and does not work well in vertical surfaces because the gas does not distribute evenly through the probe. There may be contamination that is below the detection limit of the instrument for all nuclides that can be detected using wipe tests.

19 Sensitivity and Energy Response
Sensitivity – how does the instrument respond to the level of radiation Energy Response – response of instrument may depend on the energy of the radiation Some instruments over-respond or under-respond to different radiation energies Discuss sensitivity. CSU calibrates the low scales because we expect these to be the scales used most. Show them a calibration label and read that at the x1000 scale it responds low. If we were in high levels we would calibrate the high scales. Discuss the calibrations that CSU performs for different nuclides. Take the Cl-36 check source and have one individual hold the probe at the required distance (see calibration information on the instrument) have another individual read the count rate. Calculate the activity and discuss how this can be used to determine activities of spills. Try to calibrate the instrument relative to the nuclide of interest.

20 Time Constant and Survey Speed
Slow setting (s) reduced meter fluctuations, but requires more time to stabilize Fast setting (f) increases meter fluctuations, but requires less time to stabilize and gives faster readings Does not change the audible signal Show switch and demonstrate using a source. Show reset button and how to use it. Demonstrate survey speed. Survey Speed Basic speed is 1 detector width per second as close to the source as possible without touching the source

21 High background may indicate:
What is the background? High background may indicate: Radiation Field above background Light Leak in Probe Humidity Problems Contaminated Instrument Incorrect High Voltage Not Warmed Up Intermittent Cable Connection (short) No Background then Malfunction (Maybe OK for  Probe) Show the alpha probe and the thin window. Holes in the window increase background. GM detectors with holes will continuously alarm once the gas has escaped. Humidity may short electronics. How do you know if the instrument is contaminated? Wipe test or survey with backup instrument. Must have backup in case the primary instrument is out for calibration and to check for contamination of other instruments. To clean, do not immerse in water. Take a wet towel or cloth and clean the instrument. The RCO will not pick up and calibrate contaminated instruments. High voltage discussed on next slide. Old instruments some times need to warm up. Read instruction manual. Order second cable and replace. Show that at connections it can break and work occasionally. The RCO will fix cables.

22 Calibration Survey Instruments subjected to hard use can go out of calibration Calibration information is attached to the instrument and is part of your lab records Calibrate to the nuclide of interest if possible Go over calibration information on the sticker. Take an end window GM and have an individual measure a Cs-137 check source. Record the measurement on the board. Take a pancake and have an individual measure the same source. Record the measurement on the board. Why are they so different? When an individual reports to the RCO in CPM what does it mean? Use the calibration factor on each instrument and calculate the exposure rate. Are they comparable? If they are still not close? Ask what the definition of exposure is. The Cs-137 gives off betas. This is not what the definition of exposure is. Take measurements again through the side of the end window and through the back of the pancake. The exposures should be very close. Now the measurements are comparable. Tell the individuals that they can take the measurements through the window because it will calculate a higher exposure and this works towards ALARA. Use the highest exposure measured and calculate the time to receive 5 rem (assume 1 R = 1 rem) from the source. Remember that the hands can get 50 rem (10 x more time). This is an overestimate. Discuss pulse generator calibration. Explain situations that happened at large irradiators where individuals entered a facility because a GM read 0. Individuals died and/or had major amputations because the source was exposed. Some instruments under respond at high exposures – some GM instruments read 0 and some read off scale. What does the instruction manual say?

23 Calibration Frequency
UGA performs calibrations at least annually Instrument in calibration if performed within one year For extreme conditions increase frequency Briefly discuss Immediately after performance failure After any maintenance or repair (not including battery change)

24 Check Sources Specific procedures for check source placement
Long half-life to minimize correction for decay No impurities (134Cs, 137Cs) Chemically stable Durable with handling Cross check with another instrument Contact RSO for check sources Show different check sources.

25 Conducting a Performance Check
Check for in service calibration sticker Check battery using battery check position Check for any physical damage to meter or probe Measure Background and compare to previous bkg history Measure response to check source Does speaker work? Use instrument with corresponding QA/QC and perform a daily check. Have individual perform a check without telling them how to position the source. They should be off of the chart. Tell them to do the check again, but this time tell them how to position the source. Stress the importance of describing how the source is positioned.

26 Failure of a Performance Check
DO NOT USE METER ! Use a back up meter or borrow one Remove instrument from use and contact the RSO for assistance. Your meter will need maintenance or repair and recalibration Briefly discuss.

27 Liquid Scintillation Counting
Set wipe counting protocol to full scale, 1000 channels ( 2000 KeV) Eliminate counting geometry variables Do IPC Know your typical background countrate? Use biodegradable LSF (Cocktail) Count BKG before and after sample set. Dark adapt samples including background Save all counting printouts


29 Radiation Surveys .03(7) requires radiation surveys and monitoring
Chapter 6 of the 2003 UGA Radiation Safety Manual covers Radiation Surveys

30 Radiation Monitoring and Surveys
Measurements of radiation AND contamination to evaluate the radiation hazard Contamination is any radioactive material that is in any location where it is not desired. Surveys are conducted for restricted and non-restricted working areas and areas surrounding a facility. Hand and Foot or Whole Body surveys are recommended when leaving the radiation use laboratory. How many of you survey outside of your work area? This is what the RCO provides for you to meet the CSU license requirements.

31 State Rules for Surveying and Monitoring
Must evaluate: Radiation levels Concentrations or Quantities of Radioactive Material Potential Radiological Hazards Stress the importance of potential hazards.

The primary purpose of contamination surveys are to identify the quantity (or verify the absence) of radioactive contamination on surfaces. The objective is to prevent the inhalation, ingestion, or absorption of radioactive contamination by personnel and to ensure that contamination is not spread to the surrounding environment.

Direct Scan Survey – use of the direct scan technique to measure the activity emitted from a surface. The radiation detected is the total result of any fixed and transferable contamination on the surface, and of any radiation that may be penetrating through the surface or emanating from another source.

Transferable Contamination Survey – An assessment of the amount of readily removable contamination present on a surface. A collection medium is used to wipe a surface while applying moderate pressure. The amount of activity detected on the collection medium is then determined using radiological instrumentation. 

100 cm2 Wipe Tests wipe survey – the use of a collection medium (paper disc or equivalent) to cover approximately 100 square centimeters of surface area in the assessment of transferable contamination.

36 Standard industry practice 100 cm2
Wipe Tests Standard industry practice 100 cm2 100 cm2 12” to 14” Show the size of filter paper to use and demonstrate an s-wipe. Talk about areas to wipe test and how to keep from spreading contamination. Talk about wipe test areas and to include them on the wipe test forms. 4” x 4”

Large Area Wipe Survey – the use of a collection medium ( paper towel, disposable wipe, or equivalent) to perform a transferable contamination survey of a surface area significantly larger than 100 square centimeters.

38 TYPES OF CONTAMINATION SURVEYS Large Area Wipe Survey for Floors
Masslin Mops Swiffers

Hand and foot Survey when exiting the rad work area

40 Glove Protocols Survey your gloves at times while wearing them to reduce the spread of contamination

41 Know how to remove your gloves without touching your skin or clothing!
Glove Protocols Know how to remove your gloves without touching your skin or clothing!

42 LSC standard wipe counting efficiency = 0.33 Correction Factor = 3
CPM to DPM Conversion Using the Standardized LSC Wipe Counting Efficiency LSC standard wipe counting efficiency = 0.33 Correction Factor = 3 Net cpm to equal 200 dpm = 67 cpm Net cpm to equal 1000 dpm = 333 cpm Therefore; CPM from printout x CF = DPM CPM X 3 = DPM For wipe tests with whatever Isotope

43 Transferable Contamination ALARA Action Levels
Unrestricted Area = 200 dpm/100cm2 (<66 cpm/wipe) Restricted Area = 1000 dpm/100cm2 (<333 cpm/wipe) Free Release Transferable Contamination ALARA Action Levels 200 dpm/100cm2 (<66 cpm/wipe)

44 Types of Radiation Surveys On Contact
The primary purpose of radiation surveys are to identify the magnitude (or verify the absence) of dose rates so that personnel exposure to radiation is maintained As Low As Reasonably Achievable (ALARA). The RCO will determine survey frequencies when the PU submits a project for approval. Types of Radiation Surveys On Contact 1 foot (30 cm) 1 meter

45 The performance of radiation dose rate surveys is not required in authorized use locations where the radioactive materials are limited exclusively to milliCi quantities of isotopes that emit primarily beta radiation with energies below 250 keV (H-3, C-14, S-35, and P-33). The exclusive use of I-125 immunoassay kits with <25 microCi per kit is also exempted. You must indicate what isotopes you use in the comments section of your monthly RSF Use of P-32, I-125 and all gamma producing isotopes require monthly documented radiation surveys on the RSF

46 Radiation Dose Rate ALARA Action Levels
Unrestricted Area normally occupied for 40 hours per week <0.05 mrem/hr @ cm (whole body dose rate) Restricted Area normally occupied for 40 hours per week or unrestricted area with limited occupancy (< 10 hours per week) <2 30 cm (whole body dose rate) Any doserate > 5 mR/hr, notify RSO immediately

47 Survey Records and Reports Keep for 3 Years
Explain circled items and that these can be circled as used. All instruments can be added to form and circled as used.

48 How you do the new RSF !

49 Questions ??? 542-5801
If you have any questions while reading the Radiation Safety Procedures Please Feel Free to Contact: The Radiation Safety Office Environmental Safety Division University of Georgia 240A Riverbend Road Athens, Georgia Keep checking our website for new stuff

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