Annual Refresher Training UGA Radiation Safety
Why do I need to take RSO’s Annual Refresher Training ? • To keep your Advanced Radiation Worker (ARW) or Radiation Worker (RW) certificate up to date. • To inform you of any new changes to the rad materials program. • It is an annual on-line refresher required by the State of Georgia. What do I need to do? • Make sure you registered for this training at the beginning of this presentation. • There is no formal exam, however there are random questions you can answer throughout the refresher if you want. • After you have finished the refresher, complete and print the certificate at the end and place in your laboratory’s records.
UGA’s Radiation Safety Office Our experienced staff is here to help and advise you with any radiological question, problem or emergency that you encounter. All you need to do is contact us via telephone or e-mail. The Environmental Safety Division receptionist is 542-5801 UGA’s Radiation Safety Staff Jody JacobsRadiation Safety Officer542email@example.com Dennis WidnerRadiation Safety Specialist542firstname.lastname@example.org Lauren PalmerRadiation Safety Specialist542email@example.com John PyleRadiation Safety TechnicianRad Lab Manager542firstname.lastname@example.org • Radioactive Materials Permits • Permit Amendments • Compliance Inspections • X-Ray Inspections • Dosimetry • Training • B-Number Problems • Monthly Surveys • Sealed Sources • Thyroid Bioassays • Package Delivery • Radwaste Pick-up • Meter Calibrations
UGA’S RADIATION SAFETY MANUAL Every permitted radioactive materials laboratory has been issued a hardcopy of this manual. An electronic copy is also found at our website. This manual contains all the information needed to successfully run a rad lab at UGA. All authorized users and radiation workers must be familar with this manual.
Regulations • Radioactive materials are regulated on the federal level by the Nuclear Regulatory Commission (NRC). • The state of Georgia has made an agreement with the NRC to regulate radioactive materials at the state level. • The NRC still has direct authority over radioactive materials security.
Licenses and Permits • The university has a legally binding license from the state of Georgia to possess and use certain types and quantities of radioactive materials. • Individual researchers who are approved by the UGA Radiation Safety Committee are issued Radioactive Materials Permits authorizing the possession and use of certain radioactive materials. • Radioactive Materials Permits were formerly known as licenses; that terminology is being phased out to prevent confusion with UGA’s state license.
Authorized Users • An Authorized User is an individual who has been authorized to possess and use certain types and quantities of radioactive materials. • This authorization is granted by the UGA Radiation Safety Committee in conjunction with the Radiation Safety Office. • Members of the UGA Radiation Safety Committee are appointed by the universitypresident.
How does an Authorized User make changes to an existing Radioactive Materials Permit? • Download and complete an Amendment form from the ESD/Radiation Safety website. • Send the form to Radiation Safety. • Most amendments require the approval of both the Chairman of the Radiation Safety Committee and the Radiation Safety Officer. • A copy of the approved amendment will be mailed to the Authorized User and, if necessary, the Radioactive Materials Permitwill be revised.
What kind of changes require a Radioactive Materials Permit Amendment? • Adding or removing a radioisotope from your list of approved radioactive materials. • Changing your possession limit for a radioisotope. • Changing your approved laboratory locations. • Changing your approval status for measured sewer (drain) disposal of slightly radioactive liquids. • Changing your permit to an inactive status. • Terminating the permit. • Changing the name of the Advanced Radiation Worker listed on your permit.
Which of the following best describes an Authorized User of radioactive materials at UGA? • Authorized Users have their own radioactive materials licenses issued by the state of Georgia. • The university has a radioactive materials license and Authorized Users (AUs) are issued Radioactive Materials Permits. • Authorized Users are appointed by the university president. ANSWER b
If an Authorized User is moving their radioactive materials use location to a different laboratory, the proper procedure is to: • Submit a permit amendment form to Radiation Safety before moving any radioactive materials or potentially contaminated equipment. • Move all equipment and radioactive materials, then contact Radiation Safety to post the proper signs and close out the old lab. • Properly dispose of all radioactive materials prior to moving. a ANSWER
What are the common types of radioactive materials encountered at UGA? 99% are dispersable β emitting radioisotopes such as H-3, C-14, P-32, P-33, and S-35. Of these, highly energetic P-32 has the most potential of causing skin and eye dose. 1% are dispersable gamma emitting radioisotopes such as I-125 or I-131 All radioisotopes are an internal dose hazard ! NO EATING, DRINKING, SMOKING OR CHEWING IN RAD-USE LABORATORIES !
What kind of damage can radiation exposure cause in the human body? • Radiation exposure at normal occupational levels causes no measureable health effects. • Higher levels of radiation exposure have been indicated to increase cancer risk, cause cataracts, and shorten the lifespan under some circumstances. • Extremely high radiation exposures may cause illness and even death.
Radioiodine users should get a thyroid bioassay within 10 days of using radioiodine (I-125 & I-131) to measure thyroid uptake and to establish dose assessment. All potential Radioiodine users should get a baseline count before using the material.
Dosimetry badges are worn between the neck and waist to monitor radiation exposure. The badges are sent off campus to a qualified vendor laboratory to determine the amount of radiation exposure received. Radiation exposure is measured in units of REM or milliREM. Dosimetry Badges are used to monitor personnel radiation exposure
Radiation Exposure Limits and Action Levels Exposure Acronyms DDE = deep dose equivalent (whole body penetrating exposure) TEDE = total effective dose equivalent (DDE plus dose from any intake of radioactive material) SDE = shallow dose equivalent whole body (skin dose, whole body) SDEME = shallow dose equivalent monitored extremity (extremity dose) LDE = lens dose equivalent (lens of eye exposure)
Low Energy Beta Emitters (no badge required) H-3 C-14 P-33 S-35 High Energy Beta and/or Gamma Emitters (badge normally required) P-32 I-131 I-125 Dosimetry badges are not required for persons working exclusively with low energy beta emitting radioactive materials.
Finger ring dosimetry badges are used to measure radiation exposure to the hands and should be worn on “holding” hand under your gloves. Ring badges are used infrequently and only required for certain situations, such as for persons handling >1mCi of the radioisotopes P-32 and I-125. Monitoring Radiation Exposure to the Hands
Dosimetry Badge Reminders: • Your badge is only to be used to measure radiation exposure received at UGA. • Please be cooperative with your dosimetry badge coordinator during the badge exchange process. • If you no longer need to be monitored for radiation exposure, notify Radiation Safety to have your badge service discontinued. Badge services may also be discontinued on a temporary basis when appropriate.
Users of high energy beta (P-32) or gamma emitting isotopes must survey their work areas for radiation levels. Portable instruments typically read out in units of milliRem per hour (mR/hr). Dose rate surveys are performed by holding the GM counter at waist level at the lowest setting and measuring with the probe 1 foot away from the items to be surveyed. Some items like radwaste containers must be surveyed on contact. Radiation levels in the work area are measured by using portable instruments
What is radioactive contamination? Radioactive contamination is the presence of radioactive material in an unwanted location.
Transferable Most common type of contamination. May be spread from one surface to another. Easily removed by normal surface cleaning methods. Significant risk of personnel contamination. Easily found by wipe testing. Fixed Most frequently occurs after liquid spills on porous surfaces. Not easily spread or removed by cleaning. May become transferable by physical or chemical interactions. Not detectable by wipe testing. May be found by scanning with a portable instrument. Types of Radioactive Contamination
Contamination scan considerations • Scanning must be done slowly with the probe close to the surface (low and slow). • Scanning may detect either transferable contamination, fixed contamination, or both. • The presence of other sources of radiation may interfere with contamination scans.
Wipe testing for transferable contamination • Wipe testing is a technique used to test a surface for transferable contamination. • The standard wipe test covers a surface area of 100 cm2. • Wiping a “lazy S” pattern about 16” long is the standard practice. • An appropriate number of wipes are needed to give a representative sampling of area conditions.
Liquid Scintillation Counters (LSC) and Gamma counters are used to measure wipe results. Instrument readouts in cpm are converted to dpm using our counting efficiency of 33%. Final results are expressed as dpm/100cm2.
Large Area Wipe Testing for Contamination • Large area wipe testing is normally done with a disposable paper towel. • The area wiped should cover several square feet; bench tops and floors are typical of areas checked by this method. • This technique is only used as a positive/negative test for contamination on a surface that is not known to be contaminated.
Radioactive Contamination Hazards • The main risk associated with contamination is the potential for radioactive materials to be ingested, inhaled, or absorbed through the skin of an unprotected person. • Once an intake of radioactive materials occurs, the affected person is continuously exposed to the radiation from that material until (if) it is eliminated from their body. • Contamination may also cause high radiation exposure to the skin, especially if left undetected or if high concentrations are in direct skin contact.
Contamination Control Cover benches with absorbent paper in radiological work areas. Use catch trays when working with radioactive liquids (secondary containment). Wear protective clothing. ContaminationMonitoring Perform transferable contamination surveys of work areas. Perform personnel contamination monitoring (minimum hand/shoe scan) after working with radioactive materials and/or prior to exiting the area. How do we manage the risks associated with radioactive contamination?
Personnel Contamination Monitoring • You can’t see or otherwise detect radioactive contamination without using an instrument. • A properly used portable instrument can detect all radioisotopes commonly found at UGA except for tritium (H-3). • Checking your hands and shoes only takes a minute of your time. • Don’t you want to be sure you are “clean” before you leave the lab?
Personnel Contamination Monitoring Scan your hands and shoes after working with radioactive materials.
Gloves and labcoats are primarily used to protect a radiation worker from the hazards associated with: • Radioactive contamination • Low energy beta emitters • X-rays and gamma radiation a ANSWER
Can exposure to beta, gamma, alpha radiation, or x-rays cause contamination? • No, contamination is radioactive material. Radiation is the energy emitted by radioactive material. • Beta, gamma, alpha radiation, and x-rays are energy. This energy is either scattered or absorbed by whatever material it interacts with. If the energy is absorbed, it most commonly causes ionization. • Beta, gamma, alpha radiation, and x-rays do not make the materials they interact with radioactive.
Measuring Radioactivity • The rate of radioactive events (disintegrations) occurring in a substance is the quantity of radioactivity of that substance. This is a different measurement than the amount or type of radiation emitted. • The Curie, or more typically the milliCurie (mCi) or microCurie (µCi), is the unit of measure for the quantity of radioactivity present.
RAD COUNTING PREREQUISITES Liquid Scintillation Fluid (LSF) is actually the detector and has a finite sample capacity. Sample volume should not surpass 33% of the counting vials capacity. 67% should be LSF for proper counting technique . In either type vial, the vial should be full. 20 mlvial 7 mlvial 7 mlmax 2 mlmax NOTE: Liquid Scintillation sample should be liquid with no solids or with extreme color, these will “quench” the results giving you less radiation than what’s really there.
RAD COUNTING PREREQUISITES Proper dark adaption of samples or wipe tests is very important in achieving correct values for your background and sample results.Store your sample racks in complete darkness for 10-15 minutes before counting. This can be achieved by making a Dark Adaption (DA) Protocol and counting this rack before your sample/wipe test rack. Pre and Post Backgrounds, B1 and B2 should read about the same afterproper dark adaption.
COUNTING TIMES • All wipe tests, should be countedfor 2 minutes (120 seconds) minimum. • All liquid radwaste samples should be counted for 10 minutes (600 seconds) minimum. • Counting results are statistically better if counting times are longer and sample volumes are larger.
DPM and Curie Units • 1 µCi is equal to a rate of 2.22E6 disintegrations per minute (dpm) of radioactivity. • Dpm is the unit most often used to quantify transferable contamination. • The UGA “clean area” limit for radioactive contamination is 200 dpm/100 cm2, where 100 cm2 represents the amount of area that is wipe tested.
Quantities of radioactive material are normally measured using which of the following units? • mCi, µCi, or dpm • Cpm, mCi, or mR/hr • MilliRem and dpm a ANSWER
Radioactive Half Life Radioactive half life is the amount of time required for the radioactivity of a substance to be reduced to one half of it’s original activity. Half life is very important and is used to classify radwaste as either short-lived or long-lived.
C-14 H-3 S-35 P-33 P-32 I-125 I-131 5730 years 12.3 years 87.5 days 25.3 days 14.3 days 59.9 days 8 days Half Life Values for Commonly Used Isotopes
RADIATION SURVEY REPORTING Rad surveys are performed after using rad materials or rad waste. This means documentation of several surveys per month. All rad users must do wipe testing for contamination, but P-32 and Gamma users must also do dose rate surveys as well. See Chapter 6 in the Rad Manual. Radiological surveys are to be performed in the month that they are due and all must be reported by the end of the month to the Radiation Safety Office. Surveys can be submitted with signature by campus mail, scanned and emailed or emailed from the surveyor’s UGA mail account without signature.