Safety in Depth

The vitrified glass is in stainless steel canisters which, in turn, are within 100 tonne transport casks, fixed in the hold of the ship. For the glass to become exposed, the ship's hold would need to rupture, exposing the cask, which in turn would also need to rupture, thereby exposing the canister which must also rupture, before the solid glass block itself would be exposed. Even in this incredible scenario of the glass becoming directly exposed to the sea, the leach rate of this special material in water is extremely low.

Because it is in a solid form and is characterized by long term stability and low solubility in water, there is no prospect of a 'radioactive slick'.

The results of an environmental impact assessment performed by the Japanese Science and Technology Agency show that the effect of such a scenario would be negligible.

It calculated an exposure rate to the most affected person of less than one thousandth of annual natural back-ground radiation levels.

And the protection provided by the glass, the cask and the ship ensure that even in very severe accident scenarios the radioactive contents of the waste could not be released into the atmosphere. The waste does not have explosive properties and has no military use.

The hazard posed by these shipments is therefore very small.

IAEA and IMO Member Countries