Nuclear diving:

Nuclear diving is similar to HAZMAT diving; the difference is the exposure to radiation instead of a water borne contaminant. To this end, different precautions are required for nuclear diving, mainly, equipment which will not absorb radiation and pose a disposal problem after several dives.

Heat stress can also be a danger for the diver, in which case a cold water suit may be used: the cold water suit is a special canvas coverall which floods the outside of the diver's drysuit with chilled water, countering the dangerously high ambient water temperature. A dosimeter is used to ensure that the diver does not receive a dangerous dose of radiation during the dive, assisting in calculating the maximum length of the dive. In addition the dosimeter can also be used to find radiation hotspots, which can indicate areas in need of repair.