M17.1
TRANSPORT OF RADIOACTIVE MATERIAL
(Target audience: Users of Radioisotopes of Large Activity - Mode: Air)
Introduction
Transport radioactive material is governed by national and international regulations. The International Atomic Energy Agency (IAEA) has published the Regulations for the Safe Transport of Radioactive Material [1]. All references to “Regulations” in this module pertain to the IAEA Regulations.The objective of the Regulations is to establish requirements that must be satisfied to ensure safety and to protect persons, property and the environment from the effects of radiation in the transport of radioactive material. This protection is achieved by requiring, among others:
a)containment of the radioactive contents; and
b)control of external radiation levels.
These requirements are satisfied first by specifying -
a)performance standards for package design based on the radioactive contents and
b)administrative controls and
c)approval by competent authorities.
Confidence in this regard is achieved through quality assurance and compliance assurance programmes.
Scope of this module
This module relates to the regulatory requirements for the safe transport of radioactive materialfrom –
a)facilities for treatment of cancer (telegamma therapyand brachytherapy)
b)radiation sterilization facilities for sterilizing single use medical supplies, such as syringes, gloves, cotton and bandages
c)food irradiation facilities for prevention of infestation and preservation of food
d)blood irradiation facilities
e)facilities handling self-shielded irradiators
f)radiation detector calibration facilities
g)industrial radiography institutions and
h)oil well logging facilities.
This module describes how the transport of these materials can be carried out in conformity with the applicable regulatory requirements.
Tasks before the consignor
The consignor should –
a)Familiarize himself with the regulations
b)Select the package in which the radioactive material has to be transported
c)Procure a package of currently approved design
d)Obtain the necessary approvals from the concerned competent authority/authorities
e)Prepare the package for transport (e.g. load the radioactive material in the package, fasten the closure, decontaminate the exterior of the package)
f)Mark and label the package
g)Conduct the tests before the shipment
h)Complete the transport documents including consignor’s declaration and information to the carrier.
i)Forward the package through a carrier
j)Implement radiation protection requirements and quality assurance
Familiarization with regulatory requirements
IAEA Regulations
The IAEA Regulations [1] form the basis of many national and international regulations for transport of radioactive material.
The Agency has published a Safety Guide advising the user about how the regulatory requirements can be satisfied [2]. In order to guide the consignor through the regulatory requirements, IAEA has published the Schedules for the Regulations as a Safety Guide [3]. The schedules provide specific guidance on the regulatory requirements for each type of consignment.
National Regulations
Transport of radioactive material is governed by national regulations of each State. Member States of IAEA adopt the IAEA Regulations within the frame work of the local laws and the international conventions to which the nation is a party. Accordingly, responsibilities are assigned in the National regulations to consignor, carrier and consignee. Consignors, carriers and the concerned public authorities ensure that the shipments are made in compliance with the applicable national regulations. There could be some differences between the national regulations and the international regulations for the safe transport of radioactive material because of the difference in the legal system among the states.
International Civil Aviation Organization (ICAO)
The International Civil Aviation Organization (ICAO) is also a United Nations agency. ICAO develops standards and recommends practices covering all areas of civil aviation. ICAO’s Technical Instructions prescribe the requirements for carrying radioactive material by air. These Technical Instructions are based on the IAEA Regulations with regard to the carriage of radioactive material by air.
International Air Transport Association (IATA)
IATA is an association of airlines throughout the world. Its objectives are the promotion of safe, regular and economical air transport. IATA has developed their transport regulations, which are generally consistent with the ICAO’s Technical Instructions and hence the IAEA Regulations.
Definitions of terms
Certain terms are assigned specific meanings in the Regulations. For example the terms contamination means the presence of a radioactive substance in excess of 0.4 Bq/cm2 for beta, gamma and low toxicity alpha emitters or 0.04 Bq/cm2 for other alpha emitters. The term conveyance includes road vehicles, rail cars, vessels or aircraft. A packaging together with the radioactive content is defined as package. Many definitions are provided in the Regulations. It is necessary to understand the meanings assigned to various terms in the Regulations.
A1 values and A2 values
Familiarity with A1 and A2 values defined in the Regulations would be useful. Radioactive material may be transported either in special form (essentially indispersible) and other form. The A1 value refers to the activity of special form radioactive material and the A2 value refers to the activity of other than special form radioactive material. The values of A1 and A2 have been determined for most common radionuclides and are listed in the Regulations. Multiples and fractions of A1 and A2 (for example, 3000A1, 10-3 A1, 3000A2 and 10-4 A2) are used in specifying criteria throughout the Regulations.
Selection of Package
Selection of the type of package for the transport of radioactive material is determined by the radionuclide and its activity to be transported. Let us consider the following typical examples of radioactive materials which would be transported for the purposes listed above.
Table: Examples of large radioactive sources transported
Radionuclide / Use of the radioactive material / Typical activity(TBq) / A1
(TBq) / A2
(TBq)
Cobalt-60 / Telegamma therapy / 200 / 0.4 / 0.4
Cobalt-60 / Brachythrapy / Industrial radiography / 0.4 – 0.8 / 0.4 / 0.4
Cobalt-60 / Sterilization / food irradiation / 2000 / 0.4 / 0.4
Iridium-192 / Industrial radiography / 2 / 1 / 0.6
241 Am-Be / Oil well logging / 0.4 / 10
(for 241Am) / 0.001
(for 241Am)
The radioactive materials considered in this module need to be transported in activities greater than A1 and A2 values. So they have to be transported in a Type B(U) / (M) packaging or in a Type C packaging. Type C packaging may be needed if the activity exceeds
a)3000 A1 or 100 000 A2 for special form radioactive material and
b)3000 A2 for other form radioactive material.
High activity radioactive materials such as teletherapy sources and industrial gamma radiography sources are transported in Type B(U) or B(M) packages. The design of packages used for transport of large quantities of radioactive material requires approval by the competent authority. Such approval could be either unilateral [The letter U in the designation Type B(U) represents Unilateral approval.], or multilateral [The letter M in the designation Type B(M) represents Multilateral approval.]. Certain design features of the packaging and the form of the radioactive material to be transported in the package determine the need for obtaining multilateral approval.
Unilateral approval is issued only by the competent authority of the country of origin of the design of the package. Multilateral approval needs to be issued not only by the competent authority of the country of origin of the package but also by those of the countries through or into which the package is to be transported. If a consignment is carried by air over a country multilateral approval is not required for the consignment in respect of that country, provided that there is no scheduled stop in that country.
Procurement of a package of currently approved design
Having determined the appropriate type of package for the radioactive consignment, the consignor should procure one. The package should be of approved design. The competent authority design approval certificate should be valid until the completion of the shipment.
Tests before first shipment
Before procuring the packaging, the consignor has to confirm that the supplier of the package has subjected it to the acceptance tests and confirmed that the package has been manufactured in complete conformance with the approved design.
Special arrangement
If conformity with some of the provisions of the Regulations is not practicable, the consignment can be transported but only under special arrangement. Approval for transport under special arrangement should be obtained from the concerned competent authorities.
Obtaining necessary approvals from the competent authority
The approval requirements for the sources discussed in this module are two-fold: Design approval and shipment approval. Design approval applies to sources (special form radioactive material and low dispersible radioactive material) and packages. Shipment approval applies to the carriage of certain packages.
The consignor should ensure the following:–
a)The package is of approved design
b)Where multilateral approval is required, it is obtained from the concerned competent authorities.
c)The package design approval certificate would remain valid until the completion of the shipment
d)If the radioactive material is declared as a special form radioactive material or a low dispersible radioactive material the design approval certificate of the radioactive material would be valid until completion of the shipment.
Approval of Special Form and Low Dispersible Radioactive Material
If the source is declared as a special form radioactive material or a low dispersible radioactive material the design approval certificate of the sources should be valid until completion of the shipment.
The design of special form radioactive material requires unilateral approval.
The design of low dispersible radioactive material requires multilateral approval.
Approval of package design
Each Type B(U) package design and each Type C package design requires unilateral approval.
Each Type B(U) package that is designed for the transport of low dispersible radioactive material requires multilateral approval.
Each Type B(M) package design requires multilateral approval.
The consignor should ensure the following:–
e)The package is of approved design
f)The design approval certificate would remain valid until the completion of the shipment.
Approval of Shipments
Multilateral approval is required for the shipment of a Type B(M) package if :
a)its design does not take into account temperatures ranging from – 40 °C to + 70 °C for the components of the packaging
b)it is designed to allow controlled intermittent venting or
c)the activity of the radioactive material exceeds 3000A1 or 3000A2, as appropriate, or 1000 TBq, whichever is the lower.
An application for shipment approval should include:
a)the period of time, related to the shipment, for which the approval is sought;
b)the actual radioactive contents, the expected modes of transport, the type of conveyance and the probable or proposed route; and
c)the details of how the precautions and administrative or operational controls, referred to in the package design approval certificates are to be put into effect.
Approval of Shipments under Special Arrangement
If a consignment is transported under special arrangement multilateral approval is required. An application for approval of shipments under special arrangement should include all the information necessary to satisfy the competent authority that the overall level of safety in transport is at least equivalent to that which would be provided if all the applicable requirements of these Regulations had been met. The application should also include:
a)A statement of the respects in which, and of the reasons why, the shipment cannot be made in full accordance with the applicable requirements; and
b)A statement of any special precautions or special administrative or operational controls which are to be employed during transport to compensate for the failure to meet the applicable requirements.
Preparation of the package for transport
Limits on package content
Type B(U) and Type B(M) packages should not contain activities in excess of the limits given below:
a)For special form radioactive material: 3000A1 or 100 000A2 ,
b)For low dispersible radioactive material: as authorized for the package design as specified in the certificate of approval, and
c)For all other radioactive material: 3000A2 .
A Type B(U)/B(M)/C package should not contain
a)activities greater than the limit specified in the package approval certificate issued by the competent authority.
b) radionuclides different from those authorized for the package design
contents in a form, or a physical or chemical state different from those authorized for the package design.
Control of external exposure
External exposure that may result from the transport of these sources is controlled. The Regulations impose two limits on the radiation level outside the package. One limit restricts the radiation level at the external surface of the package. The other limit restricts the radiation level at one metre from the external surface of the package. The latter number is referred to as the transport index of the package.
Transport Index (TI)
The TI is an indicator of the radiation level in the vicinity of a package or freight container. It is useful in determining the segregation distances from packages, overpacks and freight containers. The segregation distance is calculated using the inverse square law of reduction of radiation level from package. In the case of large packages radiation levels external to the loads do not decrease as per the inverse square law. Therefore a multiplication factor is introduced for large dimension loads. Segregation distances should be calculated on the basis of the TI indicated on these loads.
Here is the procedure for determining the TI of a package or overpack or freight container:
Determine the TI of a package on the basis of measured radiation levels, considering the package in isolation. Scan the package, including the top and bottom, at a distance of 1 m from the external surface. Ignore protrusions on the exterior of the package in determining the 1 m distance. However, in the case of a finned package, the measurement may be made at 1 m distance from the external envelope of the package.
Determine the maximum radiation level in units of millisieverts per hour (mSv/h) at a distance of 1 m from the external surfaces of the package, overpack, freight container.Multiply it by 100. The resulting number is the transport index of the package / overpack. In the case of freight containers this value should be multiplied by the factor given in the table below appropriate to the size of the freight container.
table: Multiplication factors for FREIGHT CONTAINERS
Size of loadaMultiplication factor
size of load 1 m21
1 m2size of load 5 m22
5 m2size of load 20 m23
20 m2<size of load10
aLargest cross-sectional area of the load being measured.
The value obtained above should be rounded up to the first decimal place (e.g. 1.13 becomes 1.2), except that a value of 0.05 or less may be considered as zero.
Alternatively, the TI for a freight container may be established as the sum of the TIs of all the packages in the freight container.
Many packages may be transported in a rigid overpack or a freight container or an aircraft.The TI, in this case, may be taken as either the sum of the TIs of all the packages contained, or by direct measurement of radiation level. Adding the TIs reflects a conservative approach as the sum of the TIs of the packages contained may be higher than the maximum radiation level at 1 m from the external surface of the overpack or the freight container due to shielding effects and the additional distance from the packages in the core of the consignment.
Limits on T I and Radiation Levels
The radiation level under routine conditions of transport should not exceed 2 mSv/h at any point on, and 0.1 mSv/h at 2 m from, the external surface of the aircraft.
The transport index of any package or overpack or freight container should not exceed 10. If this limit is exceeded, the consignment could be permitted only under exclusive use.
Exclusive use means that
a)a single consignor will have the sole use of an aircraft or of a large freight container;
b)all initial, intermediate and final loading and unloading will be carried out in accordance with the directions of the consignor or consignee;
c)the consignor has primary responsibility for ensuring compliance; and
d)the radiation level on the external surface of the package or overpack or freight container should not exceed 10 mSv/h.
While under exclusive use,the radiation level under routine conditions of transport should not exceed 2 mSv/h at any point on, and 0.1 mSv/h at 2 m from, the external surface of the aircraft.
The radiation level at any point on the external surface of a package or overpack or freight container should not exceed 2 mSv/h. If this limit is exceeded, the consignment could be permitted only by special arrangement. For transport by special arrangement, prior approval from the competent authority is required. Transport by special arrangement also requires multilateral approval.
Controls for Contamination
The radioactive materials which are specifically addressed in this module are sealed sources. In many countries such sealed sources are required to satisfy the applicable requirements for sealed sources specified by the International Organization for Standardization (ISO) [4]. Hence these radioactive materials are unlikely to cause the spread of contamination on the package or aircrafts or storage areas. However, it is good practice to check and confirm that the limits on contamination are not exceeded.
The non-fixed contamination on the external surface of any package should be kept as low as practicable. The most effective way to ensure this is to prevent the surfaces from becoming contaminated. It is advisable to check gloves or other items of clothing of personnel routinely handling packages. Under routine conditions of transport, should not exceed the following limits:
a)4 Bq / cm2 for β and γ emitters and low toxicity α emitters and
b)0.4 Bq/cm2 for all other α emitters.
Low toxicity alpha emitters are: natural uranium; depleted uranium; natural thorium; uranium-235 or uranium-238; thorium-232; thorium-228 and thorium-230 when contained in ores or physical and chemical concentrates; or alpha emitters with a half-life of less than 10 days. These limits are applicable when averaged over any area of 300 cm2 of any part of the surface.
These limits apply also to the external and internal surfaces of overpacks, fright containers and aircrafts.
Transport of other goods with radioactive shipment
Only items that are necessary for the use of the radioactive material should be contained in the package. There should be no interaction between these items and the package which could reduce the safety of the package.
If packagings are to be used for the storage or transport of other goods, then the package should first be decontaminated. That is, the level of contamination should be within these limits: