Transport of Radioactive Material
Module No.:M5
TRANSPORT OF RADIOACTIVE MATERIAL
(Target audience: Carriers)
(Mode of transport:All )
Scope
This module discusses the transport of radioactive material for various authorised applications of radiation. The module includes an introduction to radioactive materials and the uses of these materials in health care, industry and power production and certain consumer products commonly used in daily life. This module also discusses the need for the transport of radioactive material and the regulatory requirements which must be applied to ensure safety in the transport of radioactive material. The consequences of denial and delay of radioactive material shipments which comply with the applicable regulations are also included in the module.
The intended target audience for this module includes carriers for all modes of transport, viz., air, sea, road, rail and inland waterway craft.
What are radioactive materials?
Materials which emit radiation are called radioactive materials. Radiation is emitted as energy or particles. Many substances in nature are radioactive. Granite, tobacco, some natural ores, milk and beer contain naturally occurring radioactive materials. In fact, radiation is reaching us from the stars all the time. This is called the cosmic radiation. We have heard and read the names of materials like iodine-131, technetium-99m, cobalt-60, uranium-235, etc. with symbols like 131I, 99mTc, 60Co and 235U. These and other such materials are examples of radioactive materials. Some times they are called radioisotopes. Most of the radioactive materials are artificially produced. Radiations find many useful applications. The quantity of a radioactive material is generally expressed in units of Becquerel (Bq), that is., kilo Bq for one thousand Bq, Mega Bq for one million Bq, etc.
Uses of radioactive material
We shall briefly discuss some examples of the useful applications of radiation. Radioactive materials are used in many fields, namely, health care, industrial process control, quality control of industrial products, power production, agriculture and consumer products in day-to-day use.
Healthcare applications
Medical Diagnosis
A clinical procedure called nuclear medicine is very effective in studying the functioning of internal tissues and organs. In this procedure the patient is first given some radioactive material orally or by injection. The material is directed to a specific tissue/organ which is to be examined. The doctor can view on a computer monitor not merely the organ under examination but also the functioning of the organ. That is, the doctor can see the insides of a patient’s body without surgery. Such an examination does not take much time.
Every day over 75,000 such diagnostic procedures are carried out the world over. This number is increasing because the diagnosis is more accurate, faster, painless and cost-effective. Even children undergo nuclear medicine procedures which are ideal for diagnostic study of heart, lungs, liver, kidney, thyroid, bone, intestines, brain, etc or detection of cancer.
Treatment of cancer
Large doses of radiation can kill cancer cells. For thyroid cancer radioactive iodine, called iodine-131, is administered to the patient. For treatment of tumours, the radiation from a radioactive material called cobalt-60 is used. Over 45,000 treatments are carried out in more than 50 countries.
Sterilization of medical products
Large doses of radiation can kill germs. Single use medical supplies, such as syringes, gloves, cotton and bandages are sterilized using radiation from cobalt-60. Most first-aid kits found in our homes are sterilised by radiation.
Preservation of food
Enormous quantities of food grains, vegetables, spices, etc. are wasted every year due to infestation. This wastage can be stopped by treating food with radiation. Cobalt-60 is used for food irradiation.
There are many more healthcare applications. For example, irradiated blood is used in life-saving blood transfusion as it reduces the risk of immunological reaction in the recipient.
Industrial applications
Process control
For controlling the filling level of soft drinks or beer in metallic cans, the filled cans are passed between a source of radiation and a radiation detector. The filled portion of the container stops the radiation and the unfilled portion allows all radiation through. The detector finds out the filling level. This device is called a level gauge.
Radioactive materials play a useful role in industrial process control. For determining the density of materials, for example, in the dredging of rivers and harbours, density gauges are used.
Thickness gauges are used for determining very precisely the thickness of metal sheets, plastic films, papers, etc.
For exploration of oil and construction of roads, moisture gauges are used.
Industrial radiography
Defects in the welding and casting of metal objects are detected without damaging the objects by using a source of radiation. The principle is similar to the common diagnostic X-ray examination. The radiation source is kept on one side of the object being tested and X-ray films on the opposite side. A pressure vessel or an industrial boiler that has been tested by radiography is much safer than one that is not. Industrial radiography assures the quality of the product and often saves life and property.
Power production
Radioactive material (uranium compound) is used as fuel in nuclear reactors to produce clean and cost-effective power which provides lighting and heating to our homes and work places, illuminates the streets, runs the trains, moves the elevators and escalators in public places and enables the functioning of the communication systems.
Consumer products
Millions of smoke detectors operate all over the world providing early warnings of fires and thus saving lives and property. Smoke detectors use a small quantity of a radiation source.
Dials painted with luminous radioactive compounds are in common use. The dials can be read in the dark. If a power failure occurs in a theatre hall and we have to rush out for safety how do we find the exit? The “Exit” sign would go off because of the power failure! Many “Exit” signs we see in public halls glow due to the radiation from the radioactive material inside the signs. They will glow even if there is a power failure.
Radioactive materials are used in fluorescent lamps for improved efficiency.
Other uses
Radioactive material is used for determining the soil quality for agriculture and to study nutrient uptake by plants. Radioactive materials are used for detecting the presence of an element and the quantities in which it is present in a given sample. These are but a few of the uses of radioactive materials.
Not only hospitals and patients, but industrial establishments, agricultural scientists, manufacturers and users of the many industrial and consumer products and the many public utilities including communication systems operated by power delivered by nuclear plants depend on radioactive materials for the day-to-day necessities and conveniences. Radioactive materials are integral to the quality of life today.
Importance of effective and efficient transport
Radioactive materials have to be taken from the manufacturers to the users. Some of the radioactive materials have a short useful life. They are, therefore, rushed to the user by air.
For example, radiation sources used in nuclear medicine are transported in small quantities by air. If they are not used within a short period they lose their radioactivity and become almost non-radioactive substances! Because of the importance of the timing of use, patients are given appointments well in advance and the supply of the radioactive materials is scheduled accordingly. If the radioactive material does not arrive on time, patients travelling from far off places have to be sent back with a fresh appointment for a future date. The expenditure of time and money incurred in travelling and in hotel booking would be wasted. Most importantly, the diagnostic examination would be missed and the treatment that may be urgently warranted would be postponed.
Similarly, a cobalt-60 source intended for a cancer therapy facility or a sterilization plant which is transported in a package, designed to meet international standards of safety and approved by the concerned competent authorities, has to reach these places as per schedule.
If these packages are not delivered on time, many patients will go without the treatment, many tons of medical supplies or food products would miss the radiation processing. A delay in the delivery of fresh fuel to a nuclear power plant will result in reduced production of power. The consequences of reduced power are too obvious to warrant listing.
If radioactive materials are not delivered in a timely manner, it may result in considerable suffering to patients and could result in additional cost to industry.
All the concerned organizations, viz., the manufacturer, the carrier, the handler and the customer play key roles in facilitating the transport of radioactive material for the various safe applications. Radioactive materials have been routinely transported for several decades. The transport of radioactive materials is governed by regulatory requirements.
Regulations for the transport of radioactive material
IAEA Regulations
The International Atomic Energy Agency (IAEA) has developed Regulations for the Safe Transport of Radioactive Material (TS-R-1).
National Regulations
Member States of IAEA adopt the IAEA Regulations within the frame work of the local laws. Consignors, carriers and the public authorities concerned with transport of cargo ensure that the shipments are made in compliance with the applicable national regulations. There could be some differences between the national and international regulations for the safe transport of radioactive material because of the difference in the legal system among the states.
International modal regulations
The International Civil Aviation Organization (ICAO) is also a United Nations agency. ICAO develops standards and recommends practices covering all areas of civil aviation. A set of Technical Instructions published by ICAO set out in detail the requirements for carrying radioactive material by air. These Technical Instructions are based on the IAEA Regulations with regard to the carriage by air of radioactive material.
IATA is an association representing airlines throughout the world. Its objectives are the promotion of safe, regular and economical air transport. IATA has developed their transport regulations, which are consistent with the ICAO’s Technical Instructions.
The International Maritime Organization (IMO) is a United Nations agency. The regulations, standards and recommendations (IMDG Code) that it has developed, are recognized, followed, and observed by ships of many nations. This code includes provisions for the transport of radioactive material by sea.
Similarly there are other mode-specific regional international legal instruments (RID, ADR, ADN, ADNR, MERCOSUR/MERCOSUL agreement) which have to be satisfied for the transport of radioactive material. All these international regulations are based on the Regulations for the Safe Transport of Radioactive Material (TS-R-1) published by the International Atomic Energy Agency (IAEA), Vienna.
The regulations for transport of radioactive material were first published by IAEA in 1961. The regulations are reviewed by experts all over the world on a continuous basis and revised and published, as necessary.
Regulatory requirements
Package design safety and package type
The regulations focus on safe design of packages, operational control during carriage, documentation and approval requirements. Selecting the package of appropriate design achieves the desired design safety. The design requirements are based on the nature of the radioactive material that is to be transported in the package.
Radioactive materials in very small quantities, (for example, smoke detectors) are allowed to be transported in excepted packages.
Certain radioactive materials are nearly uniformly distributed in small quantities in a non-radioactive material. Such radioactive material is described as low specific activity (LSA) material. There are three sub-classifications of LSA materials, viz., LSA-I, II and III. Some non-radioactive materials carry radioactive contamination on their surfaces. Such objects are called Surface Contaminate Objects (SCO). SCOs are classified as SCO-I & II. LSA materials and SCOs are transported in Industrial Packages, IP-1/2/3.
Small quantities of radioactive materials such as radiopharmaceuticals (e.g. iodine-131, molybdenum-99) addressed to a hospital are transported in packages of simple design, known as Type A packages.
Larger quantities of radioactive materials such as teletherapy sources (e.g. cobalt-60) and spent fuel are transported in robust Type B(U) or B(M) packages.
Uranium and plutonium are radioactive materials which may be classified as fissile materials. Packages containing fissile materials and those containing uranium hexafluoride are transported in packages designed specifically for these materials.
The regulations specify the requirements relating to the type of the package, labelling and marking and documentation to be provided by the consignor and the responsibilities of the consignor and the carrier.
Handling and carriage of radioactive cargo
Before forwarding the package, the consignor must
a) measure the radiation and contamination levels and the temperature on the external surface of the package to assure that the regulatory limits are complied with and
b) mark and label the package.
It is through the markings and labels that packages communicate with the outside world. The labels and markings
§ announce the package “Type”,
§ describe the contents,
§ indicate the radiation level outside the package and
§ suggest emergency response needs.
Markings
The packages are marked in addition to being labelled. The UN number appropriate to the radioactive content should be marked on the package and included in the transport documents. For example, the UN number of a Type B(U) package containing a cobalt 60 source used for teletherapy or sterilization of medical products is UN 2916.
Labels on packages, freight containers and vehicle
The labels are to be affixed outside the packages. There are three kinds of labels which can be affixed on packages. They are called Category I- WHITE, Category II- YELLOW and Category III- YELLOW. A package with Category I-WHITE label will have very low levels of radiation. A package with Category II-YELLOW and category III-YELLOW can have relatively higher levels of radiation at the surface.
The labels describe the package contents and the radiation levels outside the packages. In the case of categories II-YELLOW and III-YELLOW, the transport index of the package is also stated on the label. The transport index (TI) is a measure of the maximum radiation level at one metre from the external surface of the package. The TI of a Category I-WHITE package is always zero. The maximum possible value of TI of a Category II-YELLOW package is 1.0. The corresponding figure for a Category III-YELLOW package is 10.0. With the help of the pictures given below one can identify the category of a package.