Heavy water is used both as a coolant and moderator in PHWRs.
Each reactor requires several hundred tonnes of heavy water. D2O storage tanks are required to supply heavy water to the primary coolant circuit and to the calandria vessel as a moderator.
Two types of tanks were manufactured for each reactor:
- RB Primary Heat Transport System D2O Storage Tank (for primary coolant circuit): 1
- Moderator D2O Storage Tank (for moderator): 1
Material: SA 516 Gr 70
- D2O Storage tanks for PHT: Dia. 3.25 m x Length 10.27m Shell 25mm Thk ; Dish End 36mm Thk
- Moderator storage tanks: Dia. 5.00m ; Length 10.98m ; Shell 12mm Thk ; Dish End 16mm Thk
- Welding: 100 % RT
- Hydro: 3.15 kg/ cm2
- Air Leak Test: 7 kg/ cm2
- Helium Leak Test: 1.05 kg/ cm2