Radiation Safety Training Module 2 – Safety and Radiation
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”
RAD WASTE CONTAINERS 30 gal. Fiber drum (CRS 768900) LINERS! 5 gal plastic bucket 2.5 gal carboy (10 L) (CRS 721925)
ALARA FOR RAM STORAGE AREAS 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.
STORAGRE DEPENDS ON TWO FACTORS TYPE OF RADIATION STRONG BETA? PHOTON EMITTER? PHYSICAL MAKE-UP CHEMICAL? BIOLOGICAL? MEDICAL? SHELF-LIFE? EXPIRATION DATE?
RADIOACTIVE STORAGE CONSIDERSTIONS WEAK BETAS –( 3H, 14C, 33P, 35 S) STORAGE IN ORIGINAL PIG, & SECONDARY CONTAINMENT STRONG BETAS – (32P) STORAGE IN ORIGINAL PIG, INSIDE LUCITE OR PLASTIC CONTAINER, SOMETIMES LEAD SHIELDING OUTSIDE ALL GAMMAS STORAGE IN ORIGINAL LEAD PIG, SECONDARY CONTAINMENT, EXTRA LEAD SHIELDING
Know where your RAM is at all times ! Utilizeproper and accurate inventory controls. Keep this form, “Summary of Isotope Inventory” up to date at all times
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.
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 !!
Survey Instruments • Portable and hand-held • Direct, real time and immediate measurements Measure: exposure rate in milliRoentgen per hour mR/hr
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 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
Recommended Survey Instrument Ludlum model 3 instrument (Part No. 48-1605) with a 202-608 meter dial and extra cable
Recommended Survey Probes General Purpose Ludlum model 44-9 (Part No. 47-1539) Alpha, Beta, Gamma pancake probe Low Energy Gamma (10-60 keV, Iodine) High Energy Gamma Ludlum model 44-2 (Part No. 47-1532) Gamma probe Ludlum model 44-3 (Part No. 47-1533) Gamma probe
What Can The Instrument Detect? Can the instrument detect tritium? Can there be contamination that the instrument cannot detect? There may be contamination that is below the detection limit of the instrument for all nuclides that can be detected using wipe tests.
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 Try to calibrate the instrument relative to the nuclide of interest.
Time Constant and Survey Speed Time Constant 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 Survey Speed Basic speed is 1 detector width per second as close to the source as possible without touching the source
Background 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)
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 Some instruments under respond at high exposures – some GM instruments read 0 and some read off scale. What does the instruction manual say?
Calibration Frequency UGA performs calibrations at least annually Instrument in calibration if performed within one year For extreme conditions increase frequency Immediately after performance failure After any maintenance or repair (not including battery change)
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
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?
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
Liquid Scintillation Counting Set wipe counting protocol to full scale, 1000 channels ( 2000 KeV)Eliminate counting geometry variablesDo IPC Know your typical background countrate? Use biodegradable LSF (Cocktail) Count BKG before and after sample set. Dark adapt samples including backgroundSave all counting printouts
Radiation Surveys • .03(7) requires radiation surveys and monitoring • Chapter 6 of the 2003 UGA Radiation Safety Manual covers Radiation Surveys
Radiation Monitoring and Surveys • Measurements of radiation ANDcontamination 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.
State Rules for Surveying and Monitoring • Must evaluate: • Radiation levels • Concentrations or Quantities of Radioactive Material • Potential Radiological Hazards
CONTAMINATION SURVEYS 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.
TYPES OF CONTAMINATION SURVEYS 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.
TYPES OF CONTAMINATION SURVEYS 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.
TYPES OF CONTAMINATION SURVEYS 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.
Wipe Tests Standard industry practice 100 cm2 100 cm2 12” to 14” 4” x 4”
TYPES OF CONTAMINATION SURVEYS 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.
TYPES OF CONTAMINATION SURVEYS Large Area Wipe Survey for Floors Masslin Mops Swiffers
TYPES OF CONTAMINATION SURVEYS Hand and foot Survey when exiting the rad work area
Glove Protocols Survey your gloves at times while wearing them to reduce the spread of contamination
Glove Protocols Know how to remove your gloves without touchingyour skin or clothing!
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
Transferable Contamination ALARA Action Levels Unrestricted Area = 200 dpm/100cm2 (<66 cpm/wipe) Restricted Area = 1000 dpm/100cm2 (<333 cpm/wipe) Free ReleaseTransferable Contamination ALARA Action Levels 200 dpm/100cm2 (<66 cpm/wipe)
Radiation Surveys RADIATION SURVEYS 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). Types of Radiation SurveysOn Contact 1 foot (30 cm) 1 meter
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
Radiation Dose Rate ALARA Action Levels Unrestricted Area normally occupied for 40 hours per week<0.05 mrem/hr @ 30 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 mrem/hr @ 30 cm (whole body dose rate) Any doserate > 5 mR/hr, notify RSO immediately
Questions ??? 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 30602-8002 542-5801 www.esd.uga.edu Keep checking our website for new stuff