Sb Shane Brightwell. HullRAC Science Summit FEBRUARY 4, Radiological Risks from NORM/TENORM Associated with Shale Gas Development

Transcription

1 Sb Shane Brightwell HullRAC Science Summit FEBRUARY 4, 2014 Radiological Risks from NORM/TENORM Associated with Shale Gas Development

2 GOALS OF THIS PRESENTATION NORM/TENORM Descriptions, Regulations Sources of NORM in the Shale Gas Development Process Risks in Perspective

3 NORM Naturally-occurring Radioactive Material Natural radioactive material in its undisturbed state Terrestrial Uranium (Unat in equilibrium), Thorium (Thnat in equilibrium), Potassium Continuous radiation emissions (alpha, beta and gamma) Sources Soil, rock - including shale

4 TENORM Technologically-enhanced NORM Altered NORM, resulting in potential increased human exposure due to Relocation Mining, drilling Radionuclides in equilibrium

5 TENORM (cont d) Technologically-enhanced NORM Altered NORM, resulting in potential increased human exposure due to Concentration of Radionuclides Processing (chemical) Disrupts radionuclide equilibrium Unat decay series cut off above Ra226 Major player in process Thnat decay series cut off above Ra228 Minor player in process

6 REGULATION Federal Level NORM and TENORM not clearly defined or regulated, indirectly regulated in some cases NORM Not specifically regulated by the Atomic Energy Act of 1954 Included in NRC definition of background radiation but not specifically defined TENORM Not specifically regulated by the Atomic Energy Act of 1954 NRC regulates TENORM as Source Material if it exceeds unimportant quantities of source material limit (>0.05%wt Unat, Thnat)

7 REGULATION (cont d) Federal Level (cont d) TENORM (cont d) NRC regulates naturally-occurring radionuclide concentrations in water effluent from operating facilities (radium limit is 60 pci/l) EPA regulates naturally-occurring radionuclide concentrations in Drinking water (radium limit is 5 pci/l) Surface soils (radium limits are 5 pci/g in top 15 cm, 15 pci/g below 15 cm) USDOT regulates TENORM as Radioactive Material if concentrations exceed their published limits (radium exemption limit is 270 pci/g)

8 REGULATION (cont d) State Level ~14 states regulate TENORM generation, possession, disposal (Ex: NJ, TX, LA) Specific regulations Licensing, license termination Generation & possession (operational) requirements Cleanup (remediation) requirements Waste management, brokering, disposal

9 REGULATION (cont d) State Level PA regulates TENORM In solid waste disposal (25 Pa. Code 273) As Source Material if it exceeds unimportant quantities of source material limit (>0.05%wt Unat, Thnat) Management that likely results in individuals exceeding general public dose limits (>100 millirem/year or mrem/yr), allowing for controls to avoid regulation (Ex: Radiation Protection Management/Action Plan) NOTE: The average background radiation level in PA from all sources is about mrem/yr; of that total, typical background environmental gamma levels are about mrem/yr ( mrem/hr, a.k.a., mr/hr).

10 REGULATION (cont d) State Level PA provides guidance for management of TENORM present in regulated activities Solid waste regs (25 Pa. Code 273) guidance Oil & gas liquid waste processing permit (WMGR 123) guidance Establishes Requirements for Radiation Protection Management/Action Plan Gamma radiation Action Levels (ALs)» AL mr/hr above background for landfill Notify recognized expert» AL 2-2 mr/hr in vehicle cab, or 50 mr/hr anywhere Notify PADEP Landfill Future Residential Farmer limit of 25 mrem/yr

11 SOURCES Site Construction Imported material Fill Typically low (natural) TENORM concentrations, some moisture content, varying grain size Quarry Stone Typically low (natural) TENORM concentrations, low moisture content, large size Drilling Cuttings Vertical Typically low (natural) TENORM concentrations, some moisture content, varying grain size Horizontal Typically low (natural) TENORM concentrations, sometimes measurably higher than vertical, some moisture content, varying grain size

12 SOURCES (cont d) Drilling (cont d) Mud Typically low (natural) TENORM concentrations, initially saturated, varying grain size NOTE: Cuttings and mud occasionally set off landfill alarms.

13 SOURCES (cont d) Hydrofracturing Flow Back Water (HTDSF) ~200,00 300,000 ppm total solids (TDS+TSS) ~90% Dissolved solids - relatively high TENORM concentrations; process mobilizes Ba & chemical analogs (Ra) ~10% suspended solids relatively low TENORM concs, similar to solids in cuttings and mud

14 SOURCES (cont d) Flow Back Water (HTDSF) Processing Sludge Solids removed from HTDSF Physical Filtration Suspended solids Moderate TENORM concentrations Chemical Processing Dissolved & suspended solids Relatively high TENORM concentrations Rn off-gassing Relatively short handling time limits radionuclide equilibrium, lower radiation levels during handling

15 SOURCES (cont d) Flow Back Water (HTDSF) Processing (cont d) Scale impacted pipes and equipment Contains relatively high concentrations of radium Typically innocuous during normal operation Scale removal produces solid waste and airborne radioparticulate Radium decay chains Gamma emissions can be readily detected through pipe/tank walls, in removed scale (alpha, beta and gamma emissions), etc.

16 SOURCES (cont d) Recycled Hydraulic Stimulation Fluid (HSF) Carryover radium Typically very low concentrations commensurate with barium (dropped out in sludge)

17 SOURCES (cont d) Production Production Water Similar solids concentration as HTDSF Accumulation of solids in tanks over relatively long periods (years) Allows radionuclide equilibrium to be established Higher gamma levels Methane / Off-gassing Radon present Typically vented to atmosphere Radon (noble gas) dispersed naturally in open atmosphere

18 SOURCES (cont d) Transmission Scale impacted pipes and equipment Contains relatively high concentrations of Pb-210 and Po-210 Typically innocuous during normal operation Scale removal produces solid waste and airborne radioparticulate Pb-210 & Po-210 cannot be readily detected by gamma signature (alpha/beta only)

19 EXPOSURE PATHWAYS Workers (drillers, drivers, facility operators, landfill workers etc.) External gamma Primary Radon inhalation Primary Inhalation of airborne dust Secondary Absorption through skin Secondary

20 EXPOSURE PATHWAYS (cont d) Landfill Future Residential Farmer Radon inhalation Primary External gamma Primary Drinking water Primary Inhalation of airborne dust Secondary Ingestion pathways (dust, foods, etc.) - Secondary Absorption through skin Secondary

21 RISKS IN PERSPECTIVE Risk of exceeding public dose limit (100 mrem/year) Site Construction Imported material Low risk; indistinguishable from background in most cases Drilling Cuttings Low human health risk, although occasionally distinguishable above background Low to moderate risk of setting off landfill radiation alarms Mud Low risk; indistinguishable from background in most cases

22 RISKS IN PERSPECTIVE (cont d) Hydrofracturing HTDSF Low risk from routine water transport, management Sludge Physical Filtration Low to moderate risk Chemically Processed Moderate risk without proper safety controls (higher TENORM concentrations, radon in closed buildings) Pipe Scale Removal Moderate to high risk without proper safety controls

23 RISKS IN PERSPECTIVE (cont d) HSF Carryover radium Low risk Production Production Water Accumulated Solids Moderate risk due to accumulation of solids with relatively high TENORM concentrations, high gamma emissions in long term Methane / Off-gassing (Radon) Low risk if not in enclosed occupied space Transmission Pipe Scale Moderate to high risk due to hard-to-detect TENORM radionuclides present in high concentrations; proper safety controls are key

24 SUMMARY Sources in Order of Decreasing Relative Risk of Exceeding Public Dose Limit of 100 mrem/yr Transmission Pipe Scale Hydrofracturing Process Pipe Scale Production Water Accumulated Solids HTDSF Sludge Methane / Off-gassing (Radon) HTDSF Drill Cuttings Drill Mud Imported Site Construction Material HSF

25 QUESTIONS Shane Brightwell, MS, CHP Professional Radiation Consulting, Inc. President