In some cases inspections and possibly repairs are carried out by man access. This requires the use of special suits to provide cooling and clean breathing air. The presence of a person in the reactor to carry out inspections or repairs provides considerable flexibility and dexterity. A person can carry out visual inspection themselves, and can often wield a camera or tools in ways which would be very difficult to achieve by remote equipment.
These are serious disadvantages to man access. Many areas such as below the dome, within the boilers and the core restraints cannot be reached because of high radiation levels or lack of access. A large team is needed to support man access and the facilities usually take up considerable space on the pile cap.
Remote equipment can operate at higher temperatures than those permitting for man access and potentially in a CO2 atmosphere. These factors can help to reduce outage times. Even though radiation doses are carefully controlled, man access represents an increased exposure to radiation which could breach the ALARP principles (see 6.3 Tolerability of Risk: the ALARP Philosophy). In summary, there are strong pressures to replace man access by the use of remote equipment.
