Radioactive materials shipments are transported by air on both short and long-haul flights, it is commonly transported by air for medical and industrials purposes either on passenger aircraft or cargo-only aircraft. Radioactive materials associated with nuclear industry are exclusively transported by road and rail or sea. Strict regulations by ICAO international civil aviation organization define how Radioactive materials shipments are safely transported by air.
In this article, I will explain how
radioactive materials shipments are safely loaded in holds of passenger
aircraft underneath cabin areas, and how airline's dangerous goods qualified
persons apply the safe distance between radioactive materials packages and
passengers and crew to protect them from unreasonable radiation exposure. Before starting explaining the process of
safe loading of radioactive materials, I will answer the following three questions:
1- What is the radiation?
Radiation comes from radioactive materials is
called ionizing radiation. Humans have no built-in sense with which to detect ionizing
radiation, therefore, radioactive materials experts use instruments to detect
it as well as to measure this type of radiation energy.
2- Can a person become radioactive from handling radioactive materials packages?
A person cannot become radioactive from the
radiation being emitted from the radioactive materials packages, but they can
become contaminated. No radioactivity or radiation remains in the person when
he is away from the radioactive materials package. He cannot expose other
people to radiation. He does not continue to be exposed himself after he moves
away from the radioactive materials package.
3- How to avoid unnecessary radiation exposure?
The main methods used to avoid unnecessary radiation
exposure rely on two key elements:
a- Time of explore, and
b- Distance from the radiation source
These two elements are applied by aircraft
loading personnel. Safety in in handling radioactive materials is based on
keeping radiation exposure as low as reasonably achievable [ by time and distance].
For safety standard regarding protecting
passengers and crew the second method [ distance] is used to keep passengers
and crew safe from contamination by radioactive materials radiations.
Safe Loading of Radioactive Materials
After giving you an idea about radioactive
materials and its radiation, it is better for you to know about the transport
index [ for radioactive materials packages], thus, will help you understand the
calculation of safety distance.
The loading process is done [ By dangerous
goods qualified persons] as the follows:
1- Reading the transport index for each package
Labels for radioactive material are the only dangerous
goods labels which require the shipper to write some information on the label.
The information is a number called (TI) the Transport Index [ only on
categories II (RRY) – yellow label and III (RRY) – yellow label], which, in
reality, is the highest radiation level at 1 meter from the surface
of the package.
Let us see this radioactive materials placard
2- Referring to IATA DGR table 10.9.C to read the requirement of separation of radioactive material
The Transport Index on III (RRY) yellow
label above is [ TI 2.0 ] and the number 2 , tell us that the radiation can by exposed by persons in 0.50 meters ( 50
cm). also this table tell us the minimum distance from each package or group of
packages to the nearest inside surface of the partitions or floors of the
flight deck or passenger cabin, or any areas occupied by other persons.
you can see this table I marked the row
which give us this distance. Also IATA DGR table 10.9.C is used to separate more
than one package of radioactive packages.
3- Knowing the aircraft type which will be used to transport the radioactive materials package.
In this article, I am going to explain
loading of radioactive material package on Airbus 310. A310 has a lower deck
holds with a proximately 1.65 m Hight [ from the hold's floor to the ceiling].
Usually, radioactive materials package is loaded on the floor of unit load
devices and secured by straps. for explanation
purpose I will explain on an image without unit load device.
Now, you must do small calculation process
as the following:
|
|
|
|
The Height of the hold |
1.65 |
|
Minus |
|
|
The Height of the radioactive material
package |
50 cm |
|
Radiation distance from the surface of
the package |
50 cm |
|
Equals |
|
|
Safety distance for passengers and crew
|
65 cm |
 |
| Safe Loading of Radioactive Materials |
Conclusion
The standard dangerous goods regulations
regarding loading of radioactive materials packages are met. Safety
consideration are should be taken if there are more than one radioactive
materials package or other dangerous goods classes are going to be loaded on
the flight.
In fact, many airlines have its specific
loading regulations which are more restrictive than the actual dangerous goods regulations.
also, states have its variations which are more restrictive from dangerous
goods regulations.
For example, United States, Code of Federal
Regulations limits the transport index and criticality safety index for
radioactive materials transported on passenger aircraft as the following "
Each single package on the aircraft has a transport index no greater than
3.0;". and "The combined
transport index and the combined criticality index of all the packages on the
aircraft are each no greater than 50.".
I hope you have benefited from this
article, and I will be happy if you share this article or refer to the aviation
professional website, so that knowledge can be circulated to all professionals
in civil aviation.
Note: I apologize to the dear readers who visited aviation professional
website several times and they did not find my new articles due to my
preoccupation with training out of my permanent resident area.