Passive safety system of integral reactor
A passive safety system includes a containment, a reactor in the containment, a plurality of safety injection tanks connected with the reactor and having water and nitrogen gas to supply water thereof into the reactor through a safety injection line communicating to the first safety injection line upon a loss of coolant accident, a plurality of core makeup tanks connected with the reactor to supply water thereof into the reactor through a second safety injection line communicating to a safety injection line upon the loss of coolant accident, and a plurality of passive residual heat removal systems to remove residual heat from the reactor upon the loss of coolant accident or a non-loss of coolant accident. The water in each of the safety injection tank is stably supplied to the reactor for many hours by a differential head resulting from gravity or gas pressure.
1. A passive safety system of an integral nuclear reactor, the passive safety system comprising:
a containment;
a reactor installed inside the containment and filled therein with a reactor coolant;
a safety injection tank, filled therein with a first water and gas, the tank connected with the reactor through a first safety injection line and configured to supply the first water into the reactor through the first safety injection line and the safety injection line when a level of the reactor coolant in the reactor is lowered due to a loss of coolant accident;
a first pressure balance line interposed between the reactor and the safety injection tank, wherein one end of the first pressure balance line is coupled with an upper portion of the reactor, and wherein the other end of the first pressure balance line is coupled with an upper portion of the safety injection tank, inserted into the first water of the safety injection tank, and provided with a plurality of perforating holes;
a core makeup tank filled therein with boric acid water, the core makeup tank connected with the reactor through a second safety injection line and configured to supply the boric acid water into the reactor through the second safety injection line when the level of the reactor coolant in the reactor is reduced upon the loss of coolant accident or a non-loss of coolant accident; and
a passive residual heat removal system connected with a feedwater line and a steam line, which are connected with a steam generator installed in the reactor to remove heat from the reactor upon the loss of coolant accident or the non-loss of coolant accident.
2. The passive safety system of claim 1 , wherein the core makeup tank is further connected with the reactor through a second pressure balance line, the second safety injection line is mounted thereon with an isolation valve, and the isolation valve is open upon the loss of coolant accident or the non-loss of coolant accident such that high-temperature steam or reactor coolant from the reactor is supplied into the core makeup tank.
3. The passive safety system of claim 2 , wherein the second pressure balance line is mounted thereon with an orifice.
4. The passive safety system of claim 1 , wherein the passive residual heat removal system comprises:
an emergency cooling tank to store a second water therein;
a condensation heat exchanger provided in the emergency cooling tank; and
a steam inlet line having one end coupled with the steam line and an opposite end coupled with the condensation heat exchanger to receive high-temperature steam through the steam line; and
a water drain line having one end coupled with the feedwater line and an opposite end coupled with the condensation heat exchanger to supply the second water in the condensation heat exchanger to the steam generator of the reactor.
5. The passive safety system of claim 1 , wherein the first safety injection line is mounted thereon with an orifice and a check valve.
6. The passive safety system of claim 1 , wherein the second safety injection line is mounted thereon with an orifice and a check valve.
7. The passive safety system of claim 1 , wherein the first pressure balance line is mounted thereon with isolation valves, such that the isolation valves are open upon the loss of coolant accident to supply high-temperature steam generated from the reactor into the safety injection tank.
8. The passive safety system of claim 7 , wherein the first pressure balance line is mounted thereon with an orifice.
9. The passive safety system of claim 7 , wherein the isolation valves includes two isolation valves, which are mounted on two branch lines, respectively, connected with the first pressure balance line such that the two isolation valves are independently operated.
10. The passive safety system of claim 7 , wherein the isolation valves is configured to receive a backup power supply from a battery to open the first pressure balance line.