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Radiation Safety Training Soil Gauges Washington State University Radiation Safety Office.

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Presentation on theme: "Radiation Safety Training Soil Gauges Washington State University Radiation Safety Office."— Presentation transcript:

1 Radiation Safety Training Soil Gauges Washington State University Radiation Safety Office

2 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.

3 Soil Gauge Probe Source Location

4 Never remove the shielding! Internal Probe Source Located Under Additional Shielding

5 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

6 Gauge handle must be Locked During Storage and Transport.

7 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.

8 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.

9 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.

10 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.

11 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.

12 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

13 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.

14 Soil Gauge Transport Box Must Have These Labels. One (1) USA DOT 7A label placed on the front side of the transport box.

15 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.

16 Soil Gauge Transport Box Must Have These Labels. (Cont.) One (1) DANGER DO NOT LOAD IN PASSENGER AIRCRAFT on top of the transport box.

17 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.

18 Test Time! Follow this link to the test. 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.

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