Refer to figure.
The intensity of radioactive material is measured in transport indices (TI) which are the amount of milisieverts (unit of radiation) received by a person at a distance of 1 m from the package. Each consignment is labelled with the number of TIs.

• The package is 0.6 m high
• The cargo compartment is 1.2 m high
• As found in the annex: A TI of 5 requires a minimum distance between the transported material and the passenger compartment of 1 m
• The top of the box of radioactive materials will be only 0.6 m from the top of the cargo compartment, which will bring it within 1 m of the passenger compartment.

Thus the goods cannot be transported in this location, they are too close to the passenger compartment.

ICAO Annex 18
8.7 Separation and segregation

8.7.1 Packages containing dangerous goods which might react dangerously one with another shall not be stowed on an aircraft next to each other or in a position that would allow interaction between them in the event of leakage.

8.7.2 Packages of toxic and infectious shall be stowed on an aircraft in accordance with the provisions of the Technical Instructions.

8.7.3 Packages of radioactive materials shall be stowed on an aircraft so that they are separated from persons, live animals and undeveloped film, in accordance with the provisions in the Technical Instructions.