These doors shield the Fueling Machine (FM), Vault Area, Fueling Machine Service Area and Fuel Transfer (FT) Room Area. They provide shielding and sealing against the nuclear radiation and radioactive atmosphere present in the FM Vault, FM Service and FT room Area for the personnel working or moving in neighbouring accessible areas. The doors are sliding type moving on rollers over machined rails.
The total system for each reactor consists of:
- FM Vault area door: 2
- FM service area door: 2
- FT room area door: 1
- Material: SA 516 Gr 70
- Dimensions: 3m x 3m x 700mm thick -Box structure filled with heavy concrete
- During Loss of Coolant Accident in FM Vaults, very high steam pressure builds up in FM Vault and FM Service Area. Hence, FM Vault Doors and FM service Area Doors are designed to withstand high differential pressures.
- Optical Laser tracker used for checking verticality.