Patent Number: 
Section: claims

1. A liquid metal cooled nuclear reactor comprising:a reactor vessel holding a reactor core and a coolant for the core;a containment surrounding an outside of the vessel;an air flow path configured to flow air around the containment to remove heat from the containment; andan injection unit configured to inject a filler in a gap between the vessel and the containment,wherein the injection unit further comprises:a liquid reservoir unit configured to reserve the filler;a connection path connecting the liquid reservoir unit and the gap; anda heater unit configured to heat the filler in the reservoir to keep the filler in a melted state. 2. The reactor according to claim 1, wherein the injection unit further comprises:a pressurization unit configured to pressurize the filler to lead the filler from the liquid reservoir unit to the gap,wherein the liquid reservoir unit is provided at a lower position than a bottom of the coolant. 3. The reactor according to claim 2, whereinthe pressurization unit has a piston, the piston moving horizontally or vertically from ends of the liquid reservoir unit toward an opening direction of the connection path in the liquid reservoir unit. 4. The reactor according to claim 1, wherein the injection unit includes a circulating path to cool down the filler having been heated in the gap. 5. The reactor according to claim 1, wherein:the injection unit further comprises a first flow-stopping valve for the filler arranged in the connection path; andthe liquid reservoir unit is provided to reserve the filler at a higher position than a top of the coolant. 6. The reactor according to claim 5, further comprising:a drain unit configured to drain the filler at a lower position of the gap than a bottom of the coolant. 7. The reactor according to claim 6, wherein the connection path connects to the gap via a pathway. 8. The reactor according to claim 6, further comprising a return path to return the filler in the drain unit to the liquid reservoir. 9. A heat removal method for a liquid metal cooled nuclear reactor including a reactor vessel holding a reactor core, a containment surrounding an outside of the reactor vessel, a liquid reservoir unit holding a filler, and a coolant for the reactor core, the method comprising:reserving the filler in the liquid reservoir unit;heating the filler in the liquid reservoir unit to keep a melted state;injecting the filler from the liquid reservoir unit into a gap between the reactor vessel and the containment; andflowing air around the containment to remove heat from the containment.