Radiation Safety Training Soil Gauges Washington State University Radiation Safety Office

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Radiation Safety Training Soil
GaugesWashington State UniversityRadiation
Safety Office
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Soil Moisture gauges.
Many industries use equipment such as nuclear
measuring gauges that incorporate a radioactive
source. These nuclear gauges provide an
inexpensive, yet highly reliable and accurate
method of measuring the moisture, density, or
composition of materials. The hydro-probe,
sometimes called Moisture gauge, measures
moisture in soil. The neutrons from a neutron
source such as Americium 241/Beryllium (Am-Be),
are moderated (slowed down/thermalized) by water
molecules and reflected into detector volume. The
detector in the gauge is only capable of
detecting moderated neutrons. Hydrogen which is a
part of the water molecule is a very effective
neutron moderator and the number of moderated
neutron is proportional to the presence of
hydrogen.
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Soil Gauge Probe Source Location
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Internal Probe Source Located Under Additional
Shielding
Never remove the shielding!
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Shielding

• Increasing the amount of shielding decreases your
  exposure. Proper thickness and appropriate
  materials are critical to shield you from a
  radiation hazard.
• Use appropriate shielding. Neutrons are
  shielded by hydrogen rich materials, such as high
  density polyethylene.
• High activity sources in storage must be
  shielded appropriately when in storage.
• Sources should be stored away from normally
  occupied areas.
• If you are uncertain about whether a source
  should be shielded or is sufficiently shielded,
  contact the Radiation Safety Office for
  information at 509-335-8916 or e-mail
  radsafe_at_ad.wsu.edu

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Gauge handle must be Locked During Storage and
Transport.
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Soil Gauge Security

• Sealed sources are typically small in size and
  may be readily portable. It is important to pay
  extra attention to ensuring that sealed and
  plated sources are secured. WSDOT and WSDOH
  Departmental Order per WAC 246-220-100 require
  that
• Sealed sources must be locked in a secured
  container or secured storage area when not in
  use.
• Any room in which a sealed source is being used
  or stored must be locked when unattended.
  Radioactive materials signs are required on the
  storage cabinet only. They are not required on
  the door to the room. Other posting required on
  the cabinet are the emergency contact list and
  the DOH RHF-3 form.

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Soil Gauge Security (cont.)

• "Three Level" method of security shall be used at
  all times, when the gauge is not under the
  physical control of the operator. The outer two
  "levels" of security shall be established such
  that each independently prevents the locked
  transport box and gauge from being removed from
  the storage location or transport vehicle by an
  unauthorized individual.

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Wipe Surveys and Sealed Source Leak Test

• The purpose of the leak test is to assess the
  removable portion of any radioactive surface
  contamination. Under the terms of the Washington
  State University's Radioactive Materials
  Licenses, the RSO must perform leak test of many
  of the sealed sources to ensure the integrity of
  the source encapsulation. Such leak tests are
  required at three or six-month intervals
  depending on the nature of the source. Leak
  testing is not required for some low-activity
  sources, however, a semi-annual inventory of
  these sources is required.
• If you suspect that a sealed or plated source has
  been damaged, notify the RSO and do not use the
  source until Radiation Safety staff have leak
  tested the source.

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State of Washington, Department of Health,
Division of Radiation Safety.

• Departmental Order Dec. 2, 2002
• We shall also require that a device be returned
  to the licensed storage location each day unless
  the job is farther than 50 miles from that
  licensed storage location. This is regardless of
  the distance from the job location to the
  operator's home.

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Transportation

• U.S. Government Department of Transportation
  (DOT) regulations control the transportation of
  radioactive materials on public roads. All gauges
  are furnished with Type A shipping and storage
  containers. They are labeled with Yellow II
  labels which means that the radiation field
  outside of the container is less than 50 mR/hr on
  any surface and less than 1.0 mR/hr at one meter
  from any surface. Under these conditions, no
  placarding of the vehicle is required. These
  devices
• must only be transported in their
• approved labeled shipping
• containers.

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During transport you must

• Block and lock instrument carrying case in the
  vehicle with gauge stored and locked within the
  carrying case.
• WSDOT requires 3 levels of security.
• 1) Gauge handle and case locked
• 2) Gauge case chained and locked
• 3) Exterior surrounding gauge case locked

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During transport (cont)

• Gauge and case must not be visible when gauge is
  not in use (cover with a tarp).
• Before leaving make sure Transportation
  Information Sheet is visible within the vehicle
  before transporting.

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Soil Gauge Transport Box Must Have These Labels.

• One (1) USA DOT 7A label placed on the front side
  of the transport box.

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Soil Gauge Transport Box Must Have These Labels.
(Cont.)

• Two (2) Yellow-II labels, one on the front side
  and one on the back side of the transport box.

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Soil Gauge Transport Box Must Have These Labels.
(Cont.)

• One (1) DANGER DO NOT LOAD IN PASSENGER AIRCRAFT
  on top of the transport box.

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Emergency Procedures.

• Damage to Sealed Radioactive Source Holder.
• Evacuate the immediate vicinity around the
  source holder.
• Place a barrier at a safe distance from the
  source holder.
• Identify the area as a radiation hazard.
• Contact your authorized user and the Radiation
  Safety Office 509-335-8916 M-F 8-5 or
• Facilities Operation 509-335-9000 after 5PM and
  weekends or if unable to reach any of the above
  call 911.

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Test Time!

• Follow this link to the test. https//myresearch.w
  su.edu
• Use your WSU user name and password to sign in.
• Click on the training tab.
• Then click on the available training tab
• Find the radiation safety training Soil Gauges
  course, in the OR section, click on it and take
  the test.