|World Nuclear Transport Industry Response to the Consultation on the new ICRP Recommendations to replace the 1990 version
The consequences of a possible imposition of a public dose constraint below 1mSv/yr for nuclear fuel cycle transport
ICRP intend to replace the 1990 Recommendations (ICRP-60) in 2005. It is possible that a public dose constraint below 1mSv/yr could be imposed in certain situations. Experience has shown that this could not be justified for nuclear fuel cycle transport operations. If it were to apply the consequences could be severe for the timely and efficient transport of radioactive materials.
In order to control radiation dose exposure to workers and the public, the IAEA Transport Regulations, TS-R-1, now require transport organisations to implement a Radiation Protection Programme. The extent of the necessary control measures relates to the magnitude and likelihood of radiation exposure.
The lowest category of transport operations is directly linked to the current ICRP maximum public dose limit of 1mSv/year and for operations below this level dose monitoring for public or workers is not required. Analysis of the data on dose up-take for various modes of transport of nuclear fuel cycle materials indicates that it is very unlikely that any group of workers not classified as radiation workers or any member of the public will receive annual doses in excess of 1mSv. Consequently, the transport of nuclear fuel cycle materials now falls into the lowest category.
However the dose up-take data also show that significant numbers of workers in the transport chain may exceed 0.3mSv/yr. If the dose constraint for the lowest category of transport operations were to be 0.3mSv/yr for nuclear fuel cycle transport then many operations would then involve classified workers and dose monitoring. This would seriously affect the operation of port facilities, the availability of sea carriers and the design and licensing of packages. It could also undermine public confidence in the safety of nuclear fuel transport.
The nuclear fuel cycle transport industry has operated successfully for decades without any significant radiological impact on man or the environment and this indicates that the case for reducing the dose constraint for transport operations could not be justified in terms of cost and benefit
1. Nuclear fuel cycle transport
The nuclear power industry, which supplies some 16% of the world’s electricity, is becoming increasingly global in terms of both products and services. The national and international transport of nuclear fuel cycle materials by all modes of transport is essential to support this activity.
In some cases nuclear fuel cycle materials are transported by dedicated carriers, such as the transport of spent fuel and HLW between Japan and Europe. However there are many transport organisations for which the transport of nuclear fuel cycle materials and sources for medical and industrial use is only a small part of their business. Typical of these are trucking companies, sea carriers, port handling organisations and airline services whose workers are not classified as radiation workers. It is important to allay the concerns of operators in the transport chain that the necessary radiation protection programmes would not be too onerous to justify in business terms.
2. The radiation protection regime
In order to control radiation dose exposure to workers and the public from transport operations the IAEA Transport Regulations, TS-R-1,  now require the organisations involved to implement a Radiation Protection Programme (RPP). It is necessary to ensure that these programmes are implemented properly to protect the public and those workers who are involved in loading and unloading operations, storage in-transit and shipment of radioactive materials, who are not classified as radiation workers.
The International Basic Safety Standards (BSS) also require operators to adopt the safety principle that, in operations giving rise to exposure, radiation protection should be optimised to reduce doses to as low as reasonably achievable, the so-called ALARA principle, which is normal practice in the nuclear industry. For nuclear fuel cycle transport, the ALARA principle can be met by demonstrating that attention has been paid to minimising dose up-take and that best practice has been adopted; for example, in the segregation and storage of containers, the shielding of drivers, the supervision of working practices, operator training, etc.
3. The graded approach based on dose assessment
Dose assessment and evaluation is a key issue for RPPs and this includes both a dose assessment at the pre-operational stage to ensure that account has been taken of all reasonably practicable radiation protection measures.
The nature and extent of control measures in the RPP relate to the magnitude and likelihood of radiation exposure. It is therefore possible to apply a graded approach to the RPP requirements as provided for in the Regulations. Where it is assessed that the dose:
• is most unlikely to exceed 1mSv/year, very little action needs to be taken in this range for
evaluating and controlling worker doses.
• is likely to be in the range 1 to 6 mSv/year, a dose assessment programme is necessary and can involve
workplace or individual dose monitoring.
• is likely to exceed 6 mSv/year, individual monitoring of transport personnel is mandatory.
This approach is directly linked to the IAEA Basic Safety Standards and the potential risks of exposures for workers and the public. The lowest category of operations is directly linked to the effective dose limit for members of the public. The requirements for an RPP are therefore considerably less onerous for operations below this level; in particular, workplace or individual dose monitoring is not required.
4. Dose assessment for nuclear fuel cycle transport operations
The Regulations accept that the above categories which determine the relevant control measures will generally be based on a prior radiological assessment using existing dose data for similar transport activities.
A study  carried out by the World Nuclear Transport Institute (WNTI) made an assessment of the likely doses to various types of worker in the transport chain and also to members of the public for the transport of various fuel cycle materials, notably uranium ore concentrate, uranium hexafluoride, uranium oxide powder, new fuel, spent fuel, plutonium, mixed oxide fuel and wastes, for various modes of transport, based mainly on experience of actual operations. Road, rail and sea transport are all commonly used for nuclear fuel cycle materials. Air transport is carried out but only to a limited extent. The individual dose up-takes to workers and the public resulting from the transport of the various nuclear fuel cycle materials by different modes of transport are summarised in this study.
The data on dose up-take during the various modes of transport of nuclear fuel cycle materials show that it is very unlikely that any group of workers not classified as radiation workers or any member of the public will receive annual doses in excess of 1mSv and consequently the transport of nuclear fuel cycle materials falls into the lowest category which is the least onerous and for which workplace or individual dose monitoring is not required.
5. Consequences of imposing a public dose constraint for nuclear fuel cycle transport operations
The dose assessment results (2) also show that significant numbers of workers in the transport chain may exceed 0.3mSv/y and if the threshold for the lowest category is set at 0.3mSv/yr then many nuclear fuel cycle transport operations would then fall into the higher categories which would involve dose monitoring. The main consequences of this are discussed below.
Transport package design and licensing
The design and performance standards for packages used for the transport of radioactive materials, including nuclear fuel cycle materials, are defined in the Regulations in order to ensure safety under both normal and accident conditions of transport. The underlying philosophy is that safety is vested principally in the package.
Packages for the more radioactive fuel cycle materials, such as spent fuel and high level wastes, and also for fissile materials, are expensive and their design, manufacture and licensing is a rigorous and time consuming process. Once approved and licensed, transport packages are manufactured and used on a world scale to support the needs of the nuclear industry. An important basis of design of packages is the current BSS and any significant change, such as a public dose constraint of 0.3mSv/yr, would have substantial implications both for the continued use of existing packages as well as the design of new ones.
Sea ports, airports, rail and road terminals
In the case of front-end, non-irradiated material transports, the transfer facilities involved for the various modes of transport are generally not dedicated to nuclear cargoes and there is presently, with the limit of 1mSv/y, no need to consider workers, such as loaders, as nuclear workers. Nuclear classification of workers at transfer facilities would make the commercial viability of handling Class 7 materials at many terminals difficult to justify.
Availability of sea carriers
For the case of sea transport of un-irradiated front-end materials, the vessels used today are often non-dedicated cargo ships on which the nuclear cargo represents a small percentage of the total cargo. It is not now necessary to classify the crews of such vessels as nuclear workers since their doses are below 1mSv/yr. The reluctance of shipping companies to ship class 7 materials is already common and any change could result in many companies deciding to drop out of the business. This would seriously reduce the number of carriers available for nuclear fuel cycle transport. It would also have a significant impact on the transport of other radioactive materials, notably sources for medical and industrial use. The situation is similar for air carriers.
The nuclear fuel cycle transport industry fully supports the need to ensure that an adequate framework of controls is applied by the various organisations in the transport chain to meet the radiation protection principles of the IAEA.
In fact, an adequate framework of controls is in place. The nuclear fuel cycle transport industry has operated successfully for decades without any significant radiological impact on man or the environment. This record of success is a tribute to the effectiveness of the regulatory framework as well as the collective competence of the organisations involved in packaging and transport activities.
The case for imposing a public dose constraint below 1mSv/yr and a consequential change to the radiation protection requirements would have a serious effect throughout the whole of the nuclear fuel cycle industry transport chain, including the design of packages, the operation of port facilities and the availability of sea carriers prepared to transport nuclear fuel cycle materials and other Class 7 goods. The record shows that this is unnecessary and could not be justified in terms of cost and benefit.
 IAEA Transport Safety Regulations, TS-R-1
 Radiation dose assessment for the Transport of Nuclear fuel cycle Materials
WNTI Review Series No. 2, WNTI, 7 Old Park Lane, London