REGULATORY TERMINOLOGY

The purpose of this chapter is to systematically explain a selection of the terms necessary to provide a general understanding of the Radioactive Material Transport Regulations. The selection of terms explained in this chapter is not in the form of the regulatory definitions. The complete set of regulatory definitions is contained in Section II (paragraphs 201-248) of TS-R-1 [1].

4.1. Special form

Special form radioactive material (paragraph 239 of TS-R-1) is either an indispersible solid radioactive material or a sealed capsule containing radioactive material. The qualification test criteria for special form are very stringent. This means that the material has a very high degree of physical integrity so that if the material were released from the package in an accident, while there might be a high radiation hazard, it is unlikely that there would be any contamination hazard. Therefore, larger quantities can typically be shipped in any given package.

4.2. A1 and A2

A1 and A2 are quantities of radioactivity (paragraph 201 of TS-R-1), which are used in the Regulations to determine such things as the type of packaging necessary for a particular radioactive material shipment. A1 applies to special form and A2 applies to other than special form radioactive material. For example, A1 is the maximum activity of special form material that is permitted in a type of package called a Type A package, and A2 is the maximum activity of other than special form radioactive material that is permitted in a Type A package.

A1 and A2 values have been determined for most common radionuclides and are listed in Table I of TS-R-1. Fractions and multiples of A1 and A2 are used in specific criteria throughout the Regulations.

4.3. Specific activity

The total quantity of radioactivity is an important parameter to know with respect to quantifying the hazards associated with a particular source. However, it does not tell the whole story. For example, 3 × 10²⁰ Bq might seem to be a very large and hazardous source, but it is the total quantity of uranium in the world’s oceans. It is a large quantity of radioactivity, but it is evenly distributed over an extremely large mass, or volume, of water.

Specific activity is usually defined in terms of activity per unit mass. In the Regulations, an important parameter for comparing specific activity is A2/g.

4.4. Exemptions

Exemptions are situations where the Regulations are not applicable. Most of these are common sense (paragraph 107 of TS-R-1), such as when the radioactive material is implanted into a person or animal, is incorporated into an approved consumer product, or is an integral part of the means of transport. The Regulations also do not apply to very low quantities of radioactive material in a consignment or very low concentrations of radioactivity that clearly represent insignificant hazards. Such material is not even defined as radioactive material (paragraph 236 of TS-R-1) in the Regulations. The basis and numerical values for these exemptions, which are the same as those in the BSS, are given in paragraphs 401-406 of TS-R-1. They are expressed in terms of specific activity (Bq/g) and total activity per consignment.

4.5. Excepted material

Excepted material is a very small quantity of radioactive material that would present insignificant hazards in the event that it was released. Excepted material is not specifically defined in the Regulations, but limits are placed upon the material and the packaging to allow shipment as an excepted package (paragraph 230(a) of TS-R-1). The basic limit for solid radioactive material contents of an excepted package is 10^-3 A1 or 10^-3 A2. Table III of TS-R-1 shows the detailed activity contents limits for excepted packages.

4.6. Low specific activity material

Low specific activity (LSA) material (paragraph 226 of TS-R-1) is radioactive material that by its nature has a low activity per unit mass (specific activity). LSA material is divided into three groups.

4.6.1. LSA-I

This material (paragraph 226(a) of TS-R-1) is intrinsically radiologically safe in that the radioactive concentration is such that a person cannot physically breathe or ingest enough of the material to give rise to significant doses. Generally, LSA-I comprises unirradiated natural or depleted Uranium and Thorium compounds and processing ores, other radionuclides with unlimited A2 values, or material with a specific activity not exceeding 30 times the exempt concentration.

4.6.2. LSA-II

LSA-II material (paragraph 226(b) of TS-R-1) includes material for which the estimated average specific activity does not exceed 10^-4 A2/g for solids and gases and 10^-5 A2/g for liquids. The activity must be distributed throughout the material. For water with tritium, the concentration limit is 0.8 TBq/L.

4.6.3. LSA-III

LSA-III material (paragraph 226(c) of TS-R-1) comprises solids in which radioactive material is distributed throughout or is essentially uniformly distributed in a solid binding agent such as concrete or bitumen. It must be relatively insoluble with a leach rate of 0.1 A2, or less, per week and a specific activity not exceeding 2 x 10^-3 A2/g.

4.7. Surface contaminated objects

A surface contaminated object (SCO) is a solid object which is not itself radioactive but which has radioactive material distributed on its surfaces. SCO is divided into two categories SCO-I (paragraph 241(a) of TS-R-1) and SCO-II (paragraph 241(b) of TS-R-1) that are differentiated by the levels of fixed and non-fixed contamination. SCO II has the higher allowed levels of contamination.

4.8. Fissile material

Fissile material (paragraph 222 of TS-R-1) is material that has the capability of undergoing nuclear fission, and thus requires additional package design considerations and controls to assure nuclear criticality safety during transport. The subject of nuclear criticality safety is considered in more detail in Chapter 11. Fissile Material, of this manual. In the

Regulations, fissile material is defined as ²³³U, ²³⁵U,²³⁹Pu,²⁴¹Pu, or any combination of these radionuclides. Natural or depleted Uranium that is unirradiated or has only been irradiated in thermal reactors is not regarded as fissile material.

4.9. Fissile excepted

Certain quantities and configurations of fissile material cannot become critical under any circumstances. To allow for this, there are several exceptions to the fissile material requirements in the Regulations (paragraph 672 of TS-R-1). Generally, the exceptions are for small quantities. For example, less than 15g per package (paragraph 672(a)(i) of TS-R-1), or for low concentrations or low enrichments. Only one type of exception is allowed per consignment. Fissile material and fissile exceptions are considered in more detail in Chapter 11 of this manual.

4.10. Consignment, consignor, consignee, carrier and conveyance

The consignment (paragraph 211 of TS-R-1) consists of the package(s) or load of radioactive material that is presented for transport. The consignor (paragraph 212 of TS-R-1) is the individual or organization that presents a consignment for transport and the consignee (paragraph 210 of TS-R-1) is the corresponding agent that receives the consignment.

A carrier (paragraph 206 of TS-R-1) is an individual or organization that undertakes the carriage of radioactive material by any means of transport. Those who do this for hire or reward are known as common or contract carriers in some countries, while the rest are called private carriers. A conveyance (paragraph 217 of TS-R-1) is the means by which the package is transported, such as a vehicle (paragraph 247 of 1), vessel (paragraph 248 of TS-R-1), or aircraft (paragraphs 202 and 203 of TS-R-1).

4.11. Exclusive use

When the consignor or consignee has total control of a shipment, then the Regulations can generally be less restrictive. This leads to the concept of exclusive use consignments (paragraph 221 of TS-R-1). Exclusive use means that a single consignor has sole use of the conveyance (or large freight container), such that all loading and unloading is carried out in accordance with the directions of the consignor or consignee.

4.12. Packaging, containment and confinement

Packaging (paragraph 231 of TS-R-1) is the assembly of components necessary to enclose the radioactive material contents, and can include such things as absorbent materials, spacing structures, shielding material, service equipment, shock absorbing devices, handling and tie-down capability, and thermal insulation. Together, the packaging and radioactive contents make up the package (paragraph 230 of TS-R-1). A containment system (paragraph 213 of TS-R-1) is defined as that part of the packaging intended to retain the radioactive material during transport. A confinement system (paragraph 209 of TS-R-1) is the assembly of fissile material and packaging components intended to preserve criticality safety.

4.12.1. Excepted packages

Excepted packages may only contain limited quantities of radioactive material, which are so small that the potential radiological hazards that might pertain during transport are very low. There are no test requirements for excepted packages and therefore it must be assumed

that in any form of accident the package may fail completely and that the contents may be dispersed. The radiation level at any point on the surface of an excepted package cannot exceed 5 µSv/h to ensure that any radiation dose to members of the public would be insignificant and that any sensitive photographic material in close proximity would not be damaged.

4.12.2. Industrial packages

Industrial packages are used to transport LSA and SCO material. There are three types of industrial packages (Type IP-1, Type IP-2, and Type IP-3) that are used for LSA and SCO shipments according to the schedule in Table IV of TS-R-1. The requirements that packages have to meet to be classified as industrial packages are not demanding. Many normal packages used in industry, such as steel drums or bins, could meet the requirements. Activity limits are fixed per conveyance as shown in Table V of TS-R-1.

4.12.3. Type A packages

Type A packages are intended to provide a safe and economical means of transporting a well defined, but significant, minor quantity of radioactive material. A total quantity of up to A1 special form radioactive material, or up to A2 if not special form, may be transported in a Type A package. They are required to maintain their integrity under the kind of abuse or mishandling which may be encountered in normal transport, for example: falling from vehicles, being dropped during manual handling, being exposed to the weather, being struck by a sharp object, or having other packages or cargo stacked on top. The specific tests required for Type A packages simulate such events.

4.12.4. Type B packages

The concept of a Type B package is that it should be capable of withstanding most accident conditions, without breach of its containment or an increase in radiation levels to a point that would endanger the general public and those involved in rescue or clean-up operations. In other words, the package could be safely recovered, but would not necessarily be capable of being reused.

While a Type B package is never required to withstand more than one accident, the design criteria imposed by the Regulations subjects the package to a series of mechanical and thermal tests with accumulative effects, each of which must cause the maximum damage. The requirements impose additional necessary design constraints over and above those imposed on packages that meet normal conditions of transport. The outcome of these constraints is to dictate greater structural integrity, more careful consideration of containment features, and the ability to protect from elevated temperatures.

For most modes of transport, a Type B package may contain any quantity of any type of radioactive material up to that allowed by its approval certificate. However, contents limits are applied if the package is transported by air. These limits are 3000 A1 or 100,000 A2

(whichever is lower) for special form material and 3000 A2 for all other forms.

Type B packages may either be unilaterally approved (B(U)), or multilaterally approved (B(M)). Unilateral approval means that they are approved by the Competent Authority of the country of origin of the design only, while multilateral approval means that they are also approved by the Competent Authorities of the countries through, or into which, the consignment is to be transported.

4.12.5. Type C packages

In recognition of the fact that impact velocities from aircraft crashes can be significantly greater than those from surface modes of transport, the shipment of very large quantities of radioactive material by air requires the use of Type C packages. These are packages that must demonstrate the capability to withstand severe crush, puncture, and fire tests, as well as impact at the high speed of 90 metres/second. These features may all be encountered in a severe air accident.

4.12.6. Fissile packages

In addition to meeting the requirements pertaining to the radioactive properties of the material, if fissile material is being transported, the package must also be designed to ensure criticality safety under a variety of postulated conditions. Such packages require multilateral Competent Authority approval and they are given the additional designation as fissile packages.

4.12.7. Overpacks, freight containers, intermediate bulk containers and tanks

Each of these is used to facilitate the handling, stowage, and carriage of goods. An overpack is an enclosure such as a box, used by a single consignor to consolidate one or more packages so they may be treated as one. A freight container is an article of transport equipment that enables goods to be easily transferred between conveyances and from one mode of transport to another. An intermediate bulk container (IBC) is a portable packaging that has a capacity less than 3 m³, which is designed for mechanical handling during transport, and meets the UN standards for IBCs. A tank has a fairly specific definition in the Regulations; however, most large containers that are envisioned when such a term is used with respect to transport will fit the definition.

4.13. Low dispersible radioactive material

Low dispersible radioactive material (LDM, see paragraph 225 of TS-R-1) is a solid material, which not only has limited dispersibility, but also has low solubility and a radiation level not exceeding 10 mSv/h at 3 metres from the unshielded material. These characteristics mean that large quantities of activity may be safely carried by air in Type B packages rather than using the Type C that would otherwise be necessary. Such material requires multilateral Competent Authority approval.

4.14. Transport index

The transport index (TI, see paragraph 243 of TS-R-1) is a number that is assigned to a package (or overpack, freight container, or conveyance), which is used to provide control over groups of packages for the purposes of minimizing radiation exposure risks.

4.15. Criticality safety index

The criticality safety index (CSI, see paragraph 218 of TS-R-1) is a number that is assigned to a package (or overpack, freight container, or conveyance) containing fissile material, which is used to provide control over the accumulation of groups of such packages for the purposes of preventing unintentional criticality.

4.16. Special arrangement

Special arrangements (paragraph 238 of TS-R-1) are those provisions that allow for the transport of consignments that do not satisfy all of the applicable regulations. These special arrangements must be approved by the affected Competent Authorities.

4.17. Competent authority

A Competent Authority (paragraph 207 of TS-R-1) is a national or international authority, which is designated or recognized as such. Practically, for most nations it is the government agency that regulates the transport of radioactive material. Amongst other things, Competent Authorities approve designs for special form radioactive material, LDM, fissile packages, and Type B and C packages. In addition, they approve special arrangements, certain shipments, and radiation protection programmes for special use vessels.

4.18. Quality assurance and compliance assurance

Quality Assurance (paragraph 232 of TS-R-1) and Compliance Assurance (paragraph 208 of TS-R-1) are systematic programmes aimed at ensuring that the standard of safety required by the Regulations is achieved in practice. Quality Assurance is applied by those involved in the transport of radioactive material, while Compliance Assurance is applied by a Competent Authority.