Transport of nuclear fuel cycle materials
Nuclear fuel cycle facilities are located in various parts of
the world and materials of many kinds need to be transported
between them. Many of these are similar to materials used in other
industrial activities. However, the nuclear industry's fuel and
waste materials are radioactive, and it is these 'nuclear
materials' about which there is most public concern.
The transport of nuclear materials has an impressive record of
safety and reliability spanning several decades. The procedures
employed are designed to ensure the protection of the public,
property and the environment.
With very few exceptions, nuclear fuel cycle materials are
transported in solid form. The following table shows the principal
nuclear material transport activities:
| From: |
To:
|
Material:
|
Notes:
|
| Mining |
Milling |
Ore |
Rare: usually on the same site |
| Milling |
Conversion |
Yellowcake |
| Conversion |
Enrichment |
Uranium hexafluoride
(Hex) |
| Enrichment |
Fuel fabrication |
Enriched Hex |
| Fuel fabrication |
Power generation |
Fresh (unused) fuel |
| Power generation |
Spent fuel storage |
Spent fuel |
After on-site storage |
| Spent fuel storage |
Disposal* |
Spent fuel |
| Spent fuel storage |
Reprocessing |
Spent fuel |
| Reprocessing |
Conversion |
Uranium oxide |
Called reprocessed uranium |
| Reprocessing |
Fuel fabrication |
Plutonium oxide |
| Reprocessing |
Disposal* |
Fission products |
Vitrified (incorporated into glass) |
| All facilities |
Storage/disposal |
Waste materials |
Sometimes on the same site |
* Not yet taking place
Packaging
Nuclear fuel cycle materials come in a variety of chemical and
physical forms and the potential hazard they present differ widely.
The underlying philosophy of the IAEA Transport Safety Regulations
is that safety is vested principally in the package - the more
hazardous the material, the tougher the package.
The Regulations specify five different primary packages;
Excepted, Industrial, Type A, Type B, and Type C, and set the
criteria for their design according to both the activity and
physical form of the radioactive material they may contain. The
Regulations also specify corresponding test procedures to
demonstrate compliance with the required performance standards.
In France alone there are around 750 shipments each year of Type
B packages, out of a total 15 million shipments classified as
'dangerous materials'.
Related Downloads:
WNTI
Fact Sheet No.2
Radiation protection
Since nuclear materials are radioactive, it is important to
ensure that radiation exposure of both those involved in the
transport of such materials and the general public along transport
routes is limited. Packaging for nuclear materials includes, where
appropriate, shielding to reduce potential radiation exposures. In
the case of some materials, such as fresh uranium fuel assemblies,
the radiation levels are negligible and no shielding is required.
Other materials, such as spent fuel and high-level waste, are
highly radioactive and purpose-designed packages with integral
shielding are used.
The IAEA Transport Safety Regulations require transport
organisations to implement Radiation Programme Programmes to
control radiation doses to workers and the public. Dose assessment
is a key feature and the three categories into which workers are
classified determine the degree of dose monitoring which is
required.
Related Downloads:
WNTI
Information Paper No.1
Environmental protection
Packages used for the transport of nuclear materials are
designed to retain their integrity during the various conditions
that may be encountered while they are being transported and to
ensure that an accident will not have any major consequences.
Regulatory performance tests include fire, impact, immersion,
pressure, heat and cold.
There has never been an accident in which a Type B transport
cask containing radioactive materials has been breached or has
leaked.
For the radioactive material in a large Type B package in sea
transit to become exposed, the ship's hold (inside double hulls)
would need to rupture, the 25 cm thick steel cask would need to
rupture, and the stainless steel flask or the fuel rods would need
to be broken open. Either borosilicate glass (for reprocessed
wastes) or ceramic fuel material would then be exposed, but in
either case these materials are very insoluble.
The INF3 Class ships for the bulk transport of radioactive
material are designed to withstand a side-on collision with a large
oil tanker. If the ship did sink, the casks would remain sound for
many years and would be relatively easy to recover since
instrumentation including location beacons would activate and
monitor the casks.
View the safety
features of the INF class ship (pdf format)
Sources:
BNFL, COGEMA, JNFL, SKB, ANSTO and WNA publications and
papers.