During voyages, our crews live and sleep within just a few metres of their radioactive cargoes. Because of the excellent protection provided by the transport containers, the crews’ annual average radiation dose is lower (0.08 mSv/yr) than the average additional dose due to a return air flight from the UK to Los Angeles, USA (0.11 mSv/yr). It’s also lower than the permitted exposure for a member of the public from a nuclear site (1mSv/yr). 

Other dose comparisons from sources of exposure include:

Source of Exposure


Dental X-ray

0.005 mSv

Chest X-ray

0.02 mSv

135g bag of Brazil nuts

0.005 mSv 

CT scan of the head

1.4 mSv

UK average annual radiation dose

2.7 mSv

Average annual radon dose to people in Cornwall

7.8 mSv

 While there is no requirement for routine dose measurement on PNTL ships, all crew members wear individual thermoluminescence dosemeters (TLDs),  to monitor individual radiation doses whenever casks  of radioactive material are on board, in line with procedures at nuclear licensed sites.