Patent Number: 
Section: claims

1. A pressure-relief system for a containment of a nuclear plant, the pressure-relief system comprising:a shutoff device;a pressure-relief line being led through the containment and being closed by said shutoff device;a wet scrubber in a section of said pressure-relief line lying outside the containment, for a pressure-relief gas flow developing in a pressure-relief operating mode with said shutoff device being open;a reservoir disposed in the containment in such a way that an overpressure, as compared with an outer environment, present in the containment, is transferred completely to said reservoir;a further shutoff device; anda feeding line, separate from and in addition to said pressure-relief line, leading from said reservoir to said wet scrubber and being closed by said further shutoff device, said feeding line configured to feed a liquid active as a scrubbing liquid from said reservoir to said wet scrubber; andsaid wet scrubber containing a washing liquid tank which is sealed with respect to a rest of an inner chamber of the containment; andsaid pressure-relief line having a throttle portion disposed upstream of a point at which said pressure-relief line opens inside said washing liquid tank. 2. The pressure-relief system according to claim 1, wherein said reservoir has a condensation chamber. 3. The pressure-relief system according to claim 1, wherein said reservoir is a pool, a pressure of said pool is equalized with respect to a rest of the containment. 4. The pressure-relief system according to claim 1, wherein said throttle portion is configured such that, at a start of a pressure-relief process, said shut-off device in said pressure-relief line being open and a pressure inside the containment being at least 2 bar absolute, a pressure inside said washing liquid tank is reduced by comparison by at least 0.3 bar. 5. The pressure-relief system according to claim 1, further comprising a fill-level control, formed by a float valve inside said washing liquid tank, for the scrubbing liquid fed in via said feeding line. 6. The pressure-relief system according to claim 1 wherein said wet scrubber is a Venturi scrubber having a Venturi tube disposed in said washing liquid tank and at a neck portion of said Venturi tube there is an intake opening formed therein for Venturi injection of the scrubbing liquid into the pressure-relief gas flow. 7. The pressure-relief system according to claim 6, further comprising an inner liquid tank for the scrubbing liquid disposed inside said washing liquid tank and encloses said intake opening in said Venturi tube, a capacity of said inner liquid tank is less than 1/10 of a total volume capacity, relative to a design filling level, of said washing liquid tank. 8. The pressure-relief system according to claim 1, further comprising a throttle device disposed in said pressure-relief line downstream of said wet scrubber when viewed in a flow direction of the pressure-relief gas flow, said throttle device configured for critical pressure relief of the pressure-relief gas flow. 9. The pressure-relief system according to claim 1, further comprising a drainage and residual heat removal system connected to said reservoir. 10. The pressure-relief system according to claim 3, wherein said a pool is an open pool. 11. The pressure-relief system according to claim 1, wherein said throttle portion is configured such that, at a start of a pressure-relief process, said shut-off device in said pressure-relief line being open and a pressure inside the containment being at least 4 bar absolute, a pressure inside said washing liquid tank is reduced by comparison by at least 1 bar. 12. A nuclear plant, comprising:a containment; anda pressure-relief system for said containment, said pressure-relief system containing:a shutoff device;a pressure-relief line being led through said containment and being closed by said shutoff device;a wet scrubber in a section of said pressure-relief line lying outside said containment, for a pressure-relief gas flow developing in a pressure-relief operating mode with said shutoff device being open;a reservoir disposed in said containment in such a way that an overpressure, as compared with an outer environment, present in said containment, is transferred completely to said reservoir;a further shutoff device; anda feeding line, separate from and in addition to said pressure-relief line, leading from said reservoir to said wet scrubber and being closed by said further shutoff device, said feeding line configured to feed a liquid active as a scrubbing liquid from said reservoir to said wet scrubber; andsaid wet scrubber containing a washing liquid tank which is sealed with respect to a rest of an inner chamber of the containment; andsaid pressure-relief line having a throttle portion disposed upstream of a point at which said pressure-relief line opens inside said washing liquid tank. 13. The nuclear plant according to claim 12, wherein said nuclear plant is a boiling water reactor nuclear plant. 14. A method for operating a pressure-relief system, the pressure-relief system containing:a shutoff device;a pressure-relief line being led through a containment and being closed by the shutoff device;a wet scrubber being switched into a section of the pressure-relief line lying outside the containment, for a pressure-relief gas flow developing in a pressure-relief operating mode with the shutoff device being open;a reservoir disposed in the containment in such a way that an overpressure, as compared with an outer environment, present in the containment, is transferred completely to the reservoir;a further shutoff device; anda feeding line, separate from and in addition to said pressure-relief line, leading from the reservoir to the wet scrubber and being closed by the further shutoff device, said feeding line configured to feed a liquid active as a scrubbing liquid from the reservoir to the wet scrubber;which method comprises the steps of:prior to or during a pressure-relief process, conveying the liquid from the reservoir into the wet scrubber, by means of the feeding line, as a result of a pressure difference between the containment and the wet scrubber. 15. The method according to claim 14, wherein, during an activation phase preceding the pressure-relief process, filling the wet scrubber for a first time by the further shut-off device in the feeding line being opened while the shut-off device in the pressure-relief line is closed. 16. The method according to claim 14, wherein, during the pressure-relief process, the shut-off device in the pressure-relief line being open and the shut-off device in the feeding line being open, used scrubbing liquid is fed back into the wet scrubber.