1 Presented By: Etech Environmental & Safety Solutions, Inc. Radiation SafetyRadiation SafetyNORMPresented By: Etech Environmental & Safety Solutions, Inc.
2 RadioactivityThe tendency of unstable atoms to undergo radioactive decay.Radioactive atoms are called radionuclides.
3 Background Radiation Is unavoidable Comes from cosmic sources and earth materialsAverages uR/hr gamma in the USA
4 What is NORM? “Naturally occurring radioactive material” The oil & gas industry is mainly concerned with 3 types of radioactive materials:Radium – 226Radium – 228Radon – 222
5 A Quick Chemistry Lesson! Uranium 238 and Thorium 232 decay and change into many different radioactive materials (daughter minerals), including Radium 226 and Radium 228, finally becoming a stable Lead (non-radioactive).
6 NORM Naturally Occurring Radioactive Material Prevalent in scale from produced water operations in certain oil fieldsMost common emitter is Alpha but can also contain Gamma & BetaGreatest hazards present for most sites are respiratory and ingestionSome sites may have time exposure potential
7 NORMRadium will dissolve readily into production water associated with oil & gas production (water rich in chlorides)It will not dissolve into the oil itself.Example: When water flooding a formation. (inject water at various areas around a formation to aid in the flow rate to the well.) The mixing of formation water and injection water can cause scale to form.
8 NORM - ScaleNORM accumulation in scale is typically the result of radium precipitating out of the produced water along with barium sulfates.
9 Major Types of Radiation Source(Symbol)Form# of ionizations per cm of AirPath Length in AirHazard Location of SourceAlpha(α)Particle100,000’s< 1 inchInternalBeta(β)100’s1 meter&ExternalGamma(γ)Electro-magnetic Energy1Several Meters to Kilometers
10 DefinitionsRoentgen – The unit of measure for X or gamma radiation in air. (R)Roentgen Absorbed Dose (RAD) – The unit of measure for radiation energy transferred to an absorbing tissue.Quality Factor – The factor by which absorbed doses are multiplied to obtain a quantity that expresses the risk associated with the dose.Roentgen Equivalent Man (REM) – The unit of measure which represents the risk associated with radiation exposure.1 R = 1 REM
11 Example Rad x QF = Rem Gamma 1 Rad x 1 = 1 Rem Beta 1 Rad x (1 to 2.6) = 1 to 2.6 RemAlpha 1 Rad x 20 = 20 REM
12 Sub-units Millirems (mRem) Microrems (µRem) 1,000,000 µRem = 1 Rem 1000 µ Rem = 1mRem1,000,000 µRem = 1 Rem
13 Acute Exposure Risk 700 Rem = LD100 600 Rem = LD99 450 Rem = LD50 200 Rem = LDLO100 Rem = TDLO25 Rem = EDLOA normal U.S. citizen has a 25% risk of cancer.1 Rem increases that risk to 25.03%.100 Rem increases the risk to 28%.The USEPA action level for personnel safety is 1mr above background
14 Why be cautious of NORM? Radium is a “bone seeker” If radium is ingested or inhaled, it will migrate to the bones of the body where it has the ability to remain for a very long time.Radium is carcinogenic and is directly linked to diseases of the bones such as leukemia and bone cancer.
15 Should I be worried?The National Council on Radiation Protection and Measurements (NCRP) has stated that while exposure of workers and the general public should be kept to the lowest practical level at all times, the presently permitted doses represent a level of risk that is small compared to other risks encountered in everyday life.
16 Exposure Reduction Mechanisms TimeAmount of time exposed to and away from the sourceDistanceCloser is not always betterShieldingDependent upon the type of radiationCan include respiratory and skin protectionALARAAs Low As Reasonably Achievable
17 Dose LimitsTotal Effective Dose Equivalent of 5 Rem per calendar year to the whole body for workers exposed to occupational radiation.For individual members of the public the dose is limited to 0.1 Rem per yearA declared pregnant women is limited to a Dose Equivalent to the Embro/Fetus of 500 mRem during her pregnancy, delivered at a recommended rate of approximately 50 mRem per month or less.
18 life expectancy loss estimate Health RisksHazardlife expectancy loss estimateSmoking (20 cig/day)6 yearsCancer3.4 yearsOverweight (15%)2 yearsAlcohol (US Avg)1 yearVehicle accidents360 daysLightning1.1 daysSingle dose of 1 mRem2.1 minutes
19 NORMNaturally occurring radioactive materials are present all around us.They are found in our backyard soil, food drinking water, even in our bodies.
20 TENORM TENORM is “technologically enhanced” Oil & gas production and refining are examples of technical processes which concentrate NORM.
21 Where NORM is found in the Oilfield Water linesFlowlinesSeparatorsWater/Production TanksPumpsHeater treaterswellheads
22 General Regulatory Information Department of State Health Services (DSHS) regulates the management (receipt, possession and storage), *transportation and *disposal of NORM.Texas Railroad Commission (TRRC) regulates the requirement for surveying tank batteries and the disposal of oil and gas NORM waste.
23 General Regulatory Requirements cont. All tank batteries must be surveyed by the operator and labeled if NORM is present…… (TRRC).Any equipment with a reading of 50uR/hr or greater (including background) is considered NORM contaminated (TRC,DSHS).Soils/BS&W with a reading of 30 pCi/g of Ra 226, Ra 228, Thorium or Total activity > 120 pCi/g is considered NORM contaminated (DSHS).
24 General Regulatory Requirements cont. All operators engaged in the possession, use, transportation or storage of NORM are a general licensee.All contractors engaged in the removal, packaging, transportation and/or disposal of NORM are required to have a specific license.
25 Contractor Requirements For each project/job a contractor must address the following:Preliminary Assessment (NORM, Physical & Chemical)Public ProtectionPersonnel ProtectionVisitorsAir MonitoringContamination MinimizationDecontamination
26 Instrumentation Determine risk of exposure Determine types of radiation
27 InstrumentsConsist of two main componentsMeterProbe (reads gamma)
28 Meters Two types Most common Analog Digital Model 3 (Analog) Model 2241 (Digital
29 Analog Meters Can be simple or complex Can be set to read in specific or multiple unitsMay require scale adjustment and use of basic math to determine the correct reading
30 Analog Meters - Scaling Reading is taken based upon the reading of the meter multiplied by the setting of the scale (Red Arrow)May require resetting (Yellow Arrow) every time the scale setting is changed or the instrument overloads the current scale
31 Digital MetersMost configured to self scale, reduces the potential for error.Depending upon the instrument configuration, will read in either uR/hr, mR/hr or CPM.Can automatically adjust for the type of probe used.
32 Probes Two primary types of probes used: Alpha/Beta Gamma ScintillationReads is uR or mR per hourAlpha/BetaCommon Name: Pancake ProbeMeasures in CPM
34 Probe Care and UseTake care to prevent the probe from falling or hitting any hard surfaceThe membrane on a “Pancake” probe can be punctured with minimal effortAll probe surfaces should be kept clean of oil, grease, dirt or significant amounts of dustNever immerse a probe in water or any other cleaning solution
35 General Instrument Care and Use Always perform a battery check before and after use.Always check the probe against a known source before and after use.Always reset the instrument when changing scales, probes or if an overload occurs.Always keep the instrument in a secure location when transporting and remove batteries.
36 Limitations of Instruments Accuracy may vary between userDistance from sourceSpeed of monitoringThickness and type of material surrounding the sourceAnnual calibration
37 NORM meters are NOT Intrinsically Safe Radiation SafetyNORM meters areNOTIntrinsically Safe
38 Radiation SafetyNever use a NORM meter in an area where explosive vapors may be present. The meter could set off an explosion.
39 Radiation SafetyAlways check for flammable vapors and H2S with an appropriate instrument before taking a NORM reading – Especially in a confined space such as a tank or a heater treater