| 摘要 |
<p>Canisters (400) containing hot spent nuclear fuel or waste are stored in respective chambers of a vault and are air-cooled by natural thermo-siphon convection. The vault is constructed from pre-cast concrete sections (120, 140, 150), assembled on-site and secured together by poured concrete (186). Each chamber has a stainless steel liner (450) defining inner and outer annular spaces (510, 520) between the hot wall (402) of the canister and the concrete wall (465) of the chamber through which cooling air flows by convection. Air from the outer space discharges via exit vents (172) cast into the concrete, air from the inner space via gap (436) between metal lid (430) and flanges (432, 434). Liner (450) shields the concrete from direct thermal radiation from the hot canister wall (402) and provides additional surfaces from which heat can be lost by convection. The inner metal-lined air path prevents very hot air from coming into direct contact with concrete. Slots (532) allow hot air to discharge via one of the exit vents in the event of blockage of the other. The concrete walls themselves are cooled by further ducts (not shown) formed as an integral part of the pre-cast structure.</p> |
