Uranium Ore Concentrate Transport

Uranium is one of a range of radioactive elements found in mineralised ore bodies that are commonly known as Naturally Occurring Radioactive Materials (NORM) [link to NORM page once created] . It is as common as tin and tungsten and about forty times as common as silver.  Uranium occurs naturally everywhere in varying concentrations averaging 3 parts per million, but it is not economic to recover uranium when it is in low concentrations. The average uranium ore concentrations of many world mines is 0.10% uranium, or 1,000 parts per million, whilst in Canada there are some mines having abundant amounts of uranium ore with grades up to 20% uranium. Research continues on trying to economically extract uranium from seawater, which exists naturally at approximately 3 parts per billion.

Uranium Ore Concentrate (UOC), is the generic term for the concentrated uranium product that is produced from the milling, grinding, leaching and other extractive chemical processes of uranium bearing ores. The resultant UOC products are chemically and physically stable forms of uranium powder packaged in steel drums to be shipped for further refining and processing for eventual use as a fuel source in nuclear reactors.

The extractive processing method applied to the treatment of the uranium ore determines the final chemical form of uranium produced and referred to as UOC.  Figure 1 is a drum of triuranium octoxide (U₃O₈); a dark khaki olive green to a blackish, brown coloured powder or granular material. It is the product resulting from the high temperature (800 deg C) decomposition of ammonium or sodium diuranate precipitate.

Uranium peroxide hydrate (UO₄) is generally a pale-yellowish to orangish coloured peroxide of uranium (figure 2). It is the product resulting from processes that utilize ion exchange or strong acid solvent extraction purification processes, is precipitated with the use of hydrogen peroxide and dried at substantially lower temperatures to UOC as U₃O₈.

Uranium dioxide or uranium oxide (UO₂), is also known as urania or uranous oxide, being an oxide of uranium, in the form of a black, radioactive, crystalline powder.

Dangerous Goods or Hazardous Materials are classified as materials that from either their physical or chemical properties may have an adverse effect on people, property and/or the environment, leading to such situations as fires, explosions, corrosion and poisoning.  Adverse health effects can be either immediate or long term. UOC is classified and referred to as being either a Dangerous Good or Hazardous Material depending on the applicable country, jurisdiction or regional location through which it is being transported.

The Proper Shipping Name comprises the universally understood standard technical name for a range of dangerous goods/hazardous materials along with additional words describing the nature, properties and composition of that material. Every category of dangerous goods or hazardous material has a corresponding United Nations Identification Number (UN number) associated with the Proper Shipping Name. This information is used by transporters and emergency response personnel to identify the nature of the dangerous goods or hazardous material being transported.

The Proper Shipping Name for UOC is ‘UN 2912 RADIOACTIVE MATERIAL, LOW SPECIFIC ACTIVITY (LSA-I)’.

Both the UN number and the Proper Shipping Name are displayed on the outside of packages and freight containers as well as on shipping and transport documents providing important safety related information to transporters, first responders and members of the public.

Many materials contain radioactive elements.  When the concentration or quantity exceeds an internationally agreed level, the material is then defined as being radioactive and therefore subject to regulatory control. The transport of radioactive material must comply with internationally agreed regulations published by the IAEA [1].

The IAEA Regulations for the Safe Transport of Radioactive Materials [1] provides a list of different classifications. UOC is classified as a ‘Low Specific Activity’ material, specifically ‘LSA-1’. This means that it is in the lowest classification of radioactive materials. UOC is also classified as ‘non-fissile or fissile excepted’. This means that the package does not contain significant quantities of fissile radioactive material, such as U-235.

The main properties of Uranium Ore Concentrates are as follows:

• Uranium like other heavy metals, is toxic and should not be inhaled or ingested.
• UOC is a mildly radioactive (natural) material that has not been enriched.
• It is not explosive, nor is it flammable or combustible.
• No fissile reaction can be initiated with this material (non-fissile material).
• It is not a marine pollutant having limited solubility in water whilst remaining stable in air and water.

The amount of external radiation exposure received by any person relates to the time a person spends near to a source of radioactive material and the intensity of the radiation emitted by that material with the radiation emitted by UOC being low. External radiation dose rate levels are practically undetectable four or five meters away from a truck loaded with UOC, merging into normal background radiation dose rate levels.  Background radiation is present everywhere, comprising radiation from naturally occurring materials in the rock and soil as well as cosmic rays.  Average annual background radiation varies depending on local geology from 1 to 10 milli-Sievert (mSv) per year around the world [2].

Radiation exposure can be easily managed by implementing simple steps such as minimising the time of exposure to the material, maximizing distance away from the material and by the use of shielding. As an example, drivers who make 100 eight-hour trips per year (two trips per week) transporting freight containers of UOC per year  between Olympic Dam and Port Adelaide would receive a total dose of about 0.8 mSv per year [3]. This is below the 1 mSv public dose limit and the normal background annual dose of 1-10mSv [2]. In comparison, the dose on a transatlantic flight is about 0.08mSv and a chest CT scan dose is around 6.6mSv [4].

UOC is prepared for transport in accordance with strict internationally agreed regulations published by the IAEA: The Regulations for the Safe Transport of Radioactive Material [1]. UOC is packaged in standard 210 litre steel drums, suitable for repeated handling, stacking and storage for extended periods of time.

For road, rail and maritime transport, UOC drums are stowed and secured in 20-foot ISO shipping containers (standard dry containers) (figure 3) and shipments can consist of several ISO freight containers. Typical transit times from mine sites to overseas conversion facilities can range from a few weeks to several months depending on the distance travelled.

UOC drums are also stowed and secured for road transport in 53-foot dry van trailers across North America. In these instances, typical transit times are generally only a few days.

Markings provide specific information describing the material and its radioactive content.

Labels provide transporters, first responders and members of the public with important safety related information identifying the hazards and the precautions required for handling.

Placards contain basic textual information along with the applicable UN identifier indicating the presence of radioactive material associated with the package or freight container.

Collectively, markings, labels and placards provide an effective internationally recognised means of communicating information about radioactive materials that are being transported by road, rail, sea or air transport.

The transport of radioactive material requires the shipper to determine and assign a Category Label to the package or freight container which relates to the dose rate measured on the surface and at a distance of one metre from the external surface of the package or freight container. Category labels which provide information about the radioactive material and dose rates are required to be applied to the outside of packages and freight container to assist transporters, emergency response personnel and members of the public to identify the nature of the dangerous goods or hazardous material being transported. Class 7 placards are placed on the outside of the freight container or conveyance to indicate that the material being transported is radioactive material.

The IAEA transport regulations require packages and freight containers to be assigned a Category depending on the external dose rate. UOC is a Category III-YELLOW radioactive material.

Drums of UOC have Category III-YELLOW labels (figure 4) affixed to two opposite sides of the outside of the drum, indicating the nature of the content (LSA-I), its activity (in Becquerels) and the value of the Transport Index (TI). (A TI of 2.0 corresponds to a dose rate of 0.02mSv/h at 1 metre from the drum).

UOC freight containers have radioactive III-YELLOW category labels and placards affixed to the four sides of the container (figure 5). The labels indicate the nature of the content (LSA-I), its activity (in Becquerels) and the value of the Transport Index (TI) for the total load. The UN number 2912 is also displayed on the four sides of the shipping container either on a rectangular orange sticker or on the radioactive placard.

Undamaged packages are quite safe to handle. However, when handling or dealing with loose (unpackaged material), gloves and respirators should be worn to avoid direct contact, inhalation and ingestion. Like other heavy metals such as lead etc. UOC should be handled carefully as uranium is toxic and should not be inhaled or ingested. If UOC is ingested or inhaled it is also possible that internal organs could receive a small radiation dose, but it is highly unlikely that a member of the public would receive an internal dose that exceeds the regulatory limit. The external radiation risks associated with uranium ore concentrate can be easily managed by simple steps such as minimising the time of exposure to the material, maximizing distance from the material, using shielding and the use of basic Personal Protection Equipment (PPE)

Protection during incident response

In the event of a spillage involving UOC during transport, the normal incident management response procedures for dangerous goods/hazardous materials should be followed. Whilst some material may be released from packages during incidents of moderate severity, the risks to people are small. A spillage of UOC does not pose any immediate radiological danger and can be managed by implementing simple steps such as minimising the time of exposure to the material, maximizing distance from the material and using shielding to protect against external radiation (for example using a parked vehicle to protect responders approaching the material). Standard protective equipment and containment, such as applying a tarpaulin, can prevent the spread of uranium and the potential for inhalation or ingestion of the material.

The first priority should always be to provide first aid to any injured persons; staying upwind of any spillage as far as possible and then to cordon off the area to limit any exposure.  In order to minimise the dispersal of any spillage, the material can be covered and contained awaiting clean-up by trained emergency responders. Assistance should be sought by contacting the local emergency services telephone number.

Cleaning up a spillage

The clean-up of a UOC spillage is similar to that of other industrial chemicals or heavy metal compounds and first responders and transporters, will have familiarity with the requisite processes. Basic PPE of disposable coveralls, PVC, rubber or cotton gloves and dust mask or respirator are all that is required for responders cleaning up a spillage.

Use brooms, shovels or specialist vacuum equipment to sweep up and collect spillage repatriating the collected materials into sealable receptacles.

Radiation and chemical risks are reduced by limiting the time of direct exposure and by avoiding direct contact, inhalation and ingestion.

The repatriation of collected spillage material should be undertaken in conjunction with local regulatory authority requirements.

Many materials contain radioactive elements. When the concentration or quantity exceeds an internationally agreed level, the material is then defined as being radioactive, becoming subject to regulatory control.

UOC is radioactive material, however it presents a very low external hazard. The primary health hazard associated with an intake of natural uranium comes from its chemical heavy metal properties, with its radiological properties being the secondary hazard. The toxicity of uranium will vary according to its chemical form and exposure route (inhalation or ingestion) and is only a hazard if the UOC is loose or spilled.

The transport of radioactive material must comply with internationally agreed regulations published by the IAEA.

Markings, Labels and Placards provide transporters, first responders and members of the public with important safety related information allowing them to identify the hazards and precautions required.

In the event of a spillage involving UOC during transport, the normal incident management response procedures for dangerous goods/hazardous materials should be followed.  Basic PPE is adequate to respond to and clean up spills.

The radiation risks associated with handling and or transporting UOC can be easily and effectively managed by implementing simple steps such as minimising the time of exposure to the package or freight container, maximizing distance from the package or freight container, using shielding and the use of basic Personal Protection Equipment.

[1] https://www.iaea.org/publications/12288/regulations-for-the-safe-transport-of-radioactive-material

[2] Sources and Effects of Ionizing Radiation, United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), 2000, www.unscear.org 

[3] BHP Billiton Olympic Dam Expansion Draft Environmental Impact Statement DEIS 2009, Appendix S Uranium and Radiation, S2.4 Doses from Transportation, www.bhp.com 

[4] UK Government Guidance Ionising Radiation: dose comparisons, March 2011, www.gov.uk