Radiation Safety

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Radiation Safety

• NORM

Presented By Etech Environmental Safety
Solutions, Inc.
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Radioactivity

• The tendency of unstable atoms to undergo
  radioactive decay.
• Radioactive atoms are called radionuclides.

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Background Radiation

• Is unavoidable
• Comes from cosmic sources and earth materials
• Averages 10 - 20 uR/hr gamma in the USA

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What is NORM?

• Naturally occurring radioactive material
• The oil gas industry is mainly concerned with 3
  types of radioactive materials
• Radium 226
• Radium 228
• Radon 222

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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).

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NORM

• Naturally Occurring Radioactive Material
• Prevalent in scale from produced water operations
  in certain oil fields
• Most common emitter is Alpha but can also contain
  Gamma Beta
• Greatest hazards present for most sites are
  respiratory and ingestion
• Some sites may have time exposure potential

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NORM

• Radium 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.

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NORM - Scale

• NORM accumulation in scale is typically the
  result of radium precipitating out of the
  produced water along with barium sulfates.

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Major Types of Radiation
Source (Symbol) Form of ionizations per cm of Air Path Length in Air Hazard Location of Source
Alpha (a) Particle 100,000s lt 1 inch Internal
Beta (ß) Particle 100s 1 meter Internal External
Gamma (?) Electro-magnetic Energy 1 Several Meters to Kilometers Internal External
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Definitions

• Roentgen 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

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Example

• Rad x QF Rem
• Gamma 1 Rad x 1 1 Rem
• Beta 1 Rad x (1 to 2.6) 1 to 2.6 Rem
• Alpha 1 Rad x 20 20 REM

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Sub-units

• Millirems (mRem)
• 1000 mRem 1 Rem
• Microrems (µRem)
• 1000 µ Rem 1mRem
• 1,000,000 µRem 1 Rem

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Acute Exposure Risk
A 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

• 700 Rem LD100
• 600 Rem LD99
• 450 Rem LD50
• 200 Rem LDLO
• 100 Rem TDLO
• 25 Rem EDLO

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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.

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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.

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Exposure Reduction Mechanisms

• Time
• Amount of time exposed to and away from the
  source
• Distance
• Closer is not always better
• Shielding
• Dependent upon the type of radiation
• Can include respiratory and skin protection
• ALARA
• As Low As Reasonably Achievable

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Dose Limits

• Total 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 year
• A 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.

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Health Risks
Hazard life expectancy loss estimate
Smoking (20 cig/day) 6 years
Cancer 3.4 years
Overweight (15) 2 years
Alcohol (US Avg) 1 year
Vehicle accidents 360 days
Lightning 1.1 days
Single dose of 1 mRem 2.1 minutes
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NORM

• Naturally occurring radioactive materials are
  present all around us.
• They are found in our backyard soil, food
  drinking water, even in our bodies.

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TENORM

• TENORM is technologically enhanced
• Oil gas production and refining are examples of
  technical processes which concentrate NORM.

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Where NORM is found in the Oilfield

• Water lines
• Flowlines
• Separators
• Water/Production Tanks
• Pumps
• Heater treaters
• wellheads

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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.

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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/BSW with a reading of 30 pCi/g of Ra 226,
  Ra 228, Thorium or Total activity gt 120 pCi/g is
  considered NORM contaminated (DSHS).

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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.

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Contractor Requirements

• For each project/job a contractor must address
  the following
• Preliminary Assessment (NORM, Physical
  Chemical)
• Public Protection
• Personnel Protection
• Visitors
• Air Monitoring
• Contamination Minimization
• Decontamination

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Instrumentation

• Determine risk of exposure
• Determine types of radiation

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Instruments

• Consist of two main components
• Meter
• Probe (reads gamma)

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Meters

• Two types
• Analog
• Digital
• Most common
• Model 3 (Analog)
• Model 2241 (Digital

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Analog Meters

• Can be simple or complex
• Can be set to read in specific or multiple units
• May require scale adjustment and use of basic
  math to determine the correct reading

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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

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Digital Meters

• Most 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.

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Probes

• Two primary types of probes used
• Gamma Scintillation
• Reads is uR or mR per hour
• Alpha/Beta
• Common Name Pancake Probe
• Measures in CPM

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Other Probes
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Probe Care and Use

• Take care to prevent the probe from falling or
  hitting any hard surface
• The membrane on a Pancake probe can be
  punctured with minimal effort
• All probe surfaces should be kept clean of oil,
  grease, dirt or significant amounts of dust
• Never immerse a probe in water or any other
  cleaning solution

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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.

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Limitations of Instruments

• Accuracy may vary between user
• Distance from source
• Speed of monitoring
• Thickness and type of material surrounding the
  source
• Annual calibration

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• NORM meters are
• NOT
• Intrinsically Safe

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• Never use a NORM meter in an area where explosive
  vapors may be present. The meter could set off
  an explosion.

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• Always 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

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Questions ?