Patent Number: 
Section: claims

1. A radioactive material reduction facility, comprising:a containment;a boundary section provided inside the containment to partition an inner space of the containment into a first space for accommodating a reactor coolant system and a second space formed between the first space and the containment;an in-containment refueling water storage tank installed inside the second space and outside the first space and formed to accommodate refueling water; anda first discharge line formed to guide a flow of steam and radioactive material formed in the first space inside the boundary section into the in-containment refueling water storage tank,wherein the in-containment refueling water storage tank comprises a plurality of pools separated from each other, and the plurality of pools comprises at least a first pool and a second pool, andthe steam and the radioactive material are discharged to the second pool through the first pool during an accident, andthe second pool is formed to accommodate the refueling water having a pH of a preset value or more so as to prevent the volatilization of the radioactive material, andwherein the first pool and the second pool are formed to accommodate the refueling water, the first pool and the second pool having a different pH from each other, and the pH of the refueling water of the second pool is higher than that of the refueling water of the first pool during an accident. 2. The radioactive material reduction facility of claim 1, wherein the boundary section comprises a partition wall formed to surround the reactor coolant system; anda cover formed to cover an upper section of the reactor coolant system. 3. The radioactive material reduction facility of claim 2, comprising:a refueling cavity formed to surround the cover at the boundary section. 4. The radioactive material reduction facility of claim 3, wherein the upper section of the reactor coolant system and the cover are formed to be detachable. 5. The radioactive material reduction facility of claim 3, further comprising:a sealing device formed to be opened and closed between the partition wall and the reactor coolant system. 6. The radioactive material reduction facility of claim 3, further comprising:a connection line formed between the in-containment refueling water storage tank and the reactor coolant system to flow refueling water. 7. The radioactive material reduction facility of claim 6, wherein refueling water is injected into the connection line by a driving force of a pump and supplied to the reactor coolant system through the connection line. 8. The radioactive material reduction facility of claim 1, further comprising: a discharge section provided at an upper section of the in-containment refueling water storage tank to prevent an overpressure of the in-containment refueling water storage tank and discharge non-condensable gas or steam into the second space. 9. The radioactive material reduction facility of claim 1, wherein the capacity of the first pool is larger than that of the second pool, and the capacity of the second pool is 1/20 to 1/10 of the capacity of the first pool. 10. The radioactive material reduction facility of claim 1, comprising:a second discharge line formed between the first pool and the second pool to flow steam and radioactive material. 11. The radioactive material reduction facility of claim 10, wherein the second discharge line is formed to discharge steam and radioactive material at a pressure lower than the pressure at which the steam and the radioactive material are discharged from the first discharge line. 12. The radioactive material reduction facility of claim 10, wherein the first discharge line further comprises a check valve formed to move steam and radioactive material formed in the first space to the in-containment refueling water storage tank. 13. The radioactive material reduction facility of claim 1, wherein refueling water in the second pool is maintained at a pH of a preset value or more to prevent the volatilization of radioactive material during a normal operation and during an accident. 14. The radioactive material reduction facility of claim 1, wherein the second pool further comprises an additive injection facility for injecting an additive into the second pool to allow a pH value of the refueling water to be maintained above the preset value. 15. The radioactive material reduction facility of claim 14, wherein the additive injection facility is formed not to inject an additive during a normal operation and formed to inject the additive during an accident. 16. A nuclear power plant, comprising a radioactive material reduction facility, said radioactive material reduction facility comprising:a containment;a boundary section provided inside the containment to partition an inner space of the containment into a first space for accommodating a reactor coolant system and a second space formed between the first space and the containment;an in-containment refueling water storage tank installed inside the second space and outside the first space and formed to accommodate refueling water; anda first discharge line formed to guide a flow of steam and radioactive material formed in the first space inside the boundary section into the in-containment refueling water storage tank,wherein the in-containment refueling water storage tank comprises a plurality of pools separated from each other, and the plurality of pools comprises at least a first pool and a second pool, andthe steam and the radioactive material are discharged to the second pool through the first pool during an accident, andthe second pool is formed to accommodate the refueling water having a pH of a preset value or more so as to prevent the volatilization of the radioactive material, andwherein the first pool and the second pool are formed to accommodate the refueling water, the first pool and the second pool having a different pH from each other, and the pH of the refueling water of the second pool is higher than that of the refueling water of the first pool during an accident. 17. The nuclear power plant of claim 16, wherein the boundary section comprises a partition wall formed to surround the reactor coolant system; anda cover formed to cover an upper section of the reactor coolant system. 18. The nuclear power plant of claim 17, wherein the radioactive material reduction facility further comprises:a refueling cavity formed to surround the cover at the boundary section. 19. The nuclear power plant of claim 18, wherein the upper section of the reactor coolant system and the cover are formed to be detachable.