Transcript Radiation Safety

Radiation Safety
NORM
Presented By: Etech Environmental & Safety Solutions, Inc.
Radioactivity

The tendency of
unstable atoms to
undergo radioactive
decay.

Radioactive atoms
are called
radionuclides.
Background Radiation

Is unavoidable

Comes from cosmic sources and earth
materials

Averages 10 - 20 uR/hr gamma in the
USA
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
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 (nonradioactive).
Uranium 238
Thorium 232
Radium 226
Radium 228
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
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.
NORM - Scale
NORM accumulation in scale is typically the
result of radium precipitating out of the
produced water along with barium
sulfates.
Major Types of Radiation
Source
(Symbol)
Form
Alpha
(α)
Particle
Beta
Particle
# of
Path Length
ionizations
in Air
per cm of Air
100,000’s
< 1 inch
Internal
100’s
1 meter
Internal
&
External
1
Several
Meters to
Kilometers
Internal
&
External
(β)
Gamma
(γ)
Electromagnetic
Energy
Hazard
Location of
Source
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
Example
Rad
Gamma 1 Rad
x
x
QF
1
= Rem
= 1 Rem
Beta
1 Rad
x
(1 to 2.6)
= 1 to 2.6 Rem
Alpha
1 Rad
x
20
= 20 REM
Sub-units

Millirems (mRem)


Microrems (µRem)


1000 mRem = 1 Rem
1000 µ Rem = 1mRem
1,000,000 µRem = 1 Rem
Acute Exposure Risk

700 Rem
=
LD100

600 Rem
=
LD99


450 Rem
200 Rem
=
=
LD50
LDLO

100 Rem
=
TDLO

25 Rem
=
EDLO
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
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.
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.
Exposure Reduction
Mechanisms

Time


Distance


Amount of time exposed to and away from the
source
Closer is not always better
Shielding

Dependent upon the type of radiation
 Can

include respiratory and skin protection
ALARA

As Low As Reasonably Achievable
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.
Health Risks
Hazard
Smoking (20 cig/day)
life expectancy
loss estimate
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
NORM
Naturally occurring radioactive materials
are present all around us.
 They are found in our backyard soil, food
drinking water, even in our bodies.

TENORM

TENORM is “technologically enhanced”

Oil & gas production and refining are
examples of technical processes which
concentrate NORM.
Where NORM is found in the
Oilfield
Water lines
 Flowlines
 Separators
 Water/Production Tanks
 Pumps
 Heater treaters
 wellheads

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.

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).
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.

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
Instrumentation

Determine risk of
exposure

Determine types of
radiation
Instruments

Consist of two main
components


Meter
Probe (reads gamma)
Meters

Two types



Analog
Digital
Most common


Model 3 (Analog)
Model 2241 (Digital
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
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
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.
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
Other Probes
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

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.
Limitations of Instruments

Accuracy may vary between user
Distance from source
 Speed of monitoring


Thickness and type of material
surrounding the source

Annual calibration
NORM meters are
NOT
Intrinsically Safe
Never use a NORM meter in an
area where explosive vapors
may be present. The meter
could set off an explosion.
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
Questions ?