INTEGRAL ISOLATION VALVE SYSTEMS AND METHODS OF OPERATING SAME FOR LOSS OF COOLANT ACCIDENT (LOCA) PROTECTION

• US 20160027535A1
• Filed: 07/22/2014
• Published: 01/28/2016
• Est. Priority Date: 07/22/2014
• Status: Active Grant

• Current Assignee: Bwxt Mpower, Inc.
• Original Assignee: Babcock & Wilcox Mpower, Inc.
• Inventors: KANUCH, David J., DiFILIPO, Paul P.
• Granted Patent: US 10,529,458 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G21C 13/02 Details
• CPC Class Codes: G21C 13/10 Means for preventing contamination in the event of leakage, e.g. double wall
• CPC Class Codes: G21C 15/18 Emergency cooling arrangements; Removing shut-down heat
• CPC Class Codes: G21C 15/182 comprising powered means, e.g. pumps
• CPC Class Codes: G21C 19/30 with continuous purification of circulating fluent material, e.g. by extraction of fission products deterioration or corrosion products, impurities, e.g. by cold traps purification of circulating fluid fuels G21C19/50; separation in general B01D
• CPC Class Codes: G21C 9/00 Emergency protection arrangements structurally associated with the reactor , e.g. safety valves provided with pressure equalisation devicesemergency cooling arrangements G21C15/18
• CPC Class Codes: Y02E 30/30 Nuclear fission reactors

Abstract

A nuclear reactor includes a nuclear reactor core comprising fissile material disposed in a reactor pressure vessel having vessel penetrations that exclusively carry flow into the nuclear reactor and at least one vessel penetration that carries flow out of the nuclear reactor. An integral isolation valve (IIV) system includes passive IIVs each comprising a check valve built into a forged flange and not including an actuator, and one or more active IIVs each comprising an active valve built into a forged flange and including an actuator. Each vessel penetration exclusively carrying flow into the nuclear reactor is protected by a passive IIV whose forged flange is directly connected to the vessel penetration. Each vessel penetration carrying flow out of the nuclear reactor is protected by an active IIV whose forged flange is directly connected to the vessel penetration. Each active valve may be a normally closed valve.

Claims

1. A nuclear island comprising:

a nuclear reactor including a nuclear reactor core comprising fissile material disposed in a reactor pressure vessel;

an emergency core cooling (ECC) system connected to the nuclear reactor through an ECC vessel feedthrough;

a reactor coolant inventory and purification system (RCIPS) connected to the nuclear reactor to inject coolant into the reactor pressure vessel through a make-up line vessel feedthrough and to extract coolant from the reactor pressure vessel through a let-down line vessel feedthrough; and

an integral isolation valve (IIV) system including;

a passive IIV comprising a check valve built into a forged flange that is connected directly to the ECC vessel feedthrough,

a passive IIV comprising a check valve built into a forged flange that is connected directly to the make-up line vessel feedthrough, and

an active IIV comprising an active valve built into a forged flange that is connected directly to the let-down line vessel feedthrough.

2. The nuclear island of claim 1 further comprising:

a residual heat removal (RHR) system having an RHR inlet connected to the nuclear reactor to through an RHR out vessel feedthrough and an RHR outlet connected to the nuclear reactor to through an RHR return vessel feedthrough;

wherein the IIV system further includes;

a passive IIV comprising a check valve built into a forged flange that is connected directly to the RHR return vessel feedthrough, and

an active IIV comprising an active valve built into a forged flange that is connected directly to the RHR out vessel feedthrough.

3. The nuclear island of claim 2 wherein the RHR system comprises an air- or water-cooled RHR heat exchanger.

4. The nuclear island of claim 2 further comprising:

a pressure sensor disposed in the reactor pressure vessel and configured to sense reactor coolant pressure; and

a reactor control system configured to close the active IIV connected directly to the RHR out vessel feedthrough in response to the reactor coolant pressure sensed by the pressure sensor exceeding a threshold pressure.

5. The nuclear island of claim 1 further comprising:

a level sensor disposed in the reactor pressure vessel and configured to sense reactor coolant level;

a reactor control system configured to close the active IIV connected directly to the letdown line vessel feedthrough in response to the reactor coolant level sensed by the pressure sensor falling below a threshold reactor coolant level.

6. A nuclear island comprising:

a nuclear reactor including a nuclear reactor core comprising fissile material disposed in a reactor pressure vessel that has a plurality of vessel penetrations that exclusively carry flow into the nuclear reactor and at least one vessel penetration that carries flow out of the nuclear reactor; and

an integral isolation valve (IIV) system including;

a plurality of passive IIVs each comprising a check valve built into a forged flange and not including an actuator, and

one or more active IIVs each comprising an active valve built into a forged flange and including an actuator,

wherein;

each vessel penetration that exclusively carries flow into the nuclear reactor is protected by a passive IIV whose forged flange is directly connected to the vessel penetration, and

each vessel penetration that carries flow out of the nuclear reactor is protected by an active IIV whose forged flange is directly connected to the vessel penetration.

7. The nuclear island of claim 6 wherein each vessel penetration that carries flow out of the nuclear reactor exclusively carries flow out of the nuclear reactor.

8. The nuclear island of claim 6 wherein each active IIV further includes a manual backup for the actuator.

9. The nuclear island of claim 6 further comprising:

an emergency core cooling (ECC) system connected to the nuclear reactor through a vessel penetration that exclusively carries flow into the nuclear reactor and is protected by a passive IIV whose forged flange is directly connected to the vessel penetration.

10. The nuclear island of claim 6 further comprising:

a reactor coolant inventory and purification system (RCIPS) connected to the nuclear reactor to inject coolant into the reactor pressure vessel through a vessel penetration that exclusively carries flow into the nuclear reactor and is protected by a passive IIV whose forged flange is directly connected to the vessel penetration.

11. The nuclear island of claim 10 wherein the RCIPS is further connected to the nuclear reactor to extract coolant from the reactor pressure vessel through a vessel penetration that exclusively carries flow out of the nuclear reactor and is protected by an active IIV whose forged flange is directly connected to the vessel penetration.

12. The nuclear island of claim 11 further comprising:

a residual heat removal (RHR) system having;

an inlet connected to the nuclear reactor through a vessel penetration that exclusively carries flow out of the nuclear reactor and is protected by an active IIV whose forged flange is directly connected to the vessel penetration, and

an outlet connected to the nuclear reactor through a vessel penetration that exclusively carries flow into the nuclear reactor and is protected by a passive IIV whose forged flange is directly connected to the vessel penetration.

13. The nuclear island of claim 6 further comprising:

a residual heat removal (RHR) system having;

an inlet connected to the nuclear reactor through a vessel penetration that exclusively carries flow out of the nuclear reactor and is protected by an active IIV whose forged flange is directly connected to the vessel penetration, and

an outlet connected to the nuclear reactor through a vessel penetration that exclusively carries flow into the nuclear reactor and is protected by a passive IIV whose forged flange is directly connected to the vessel penetration.

14. The nuclear island of claim 6 wherein the check valve of each passive IIV admits flow at above a threshold pressure into the reactor pressure vessel, while blocking flow otherwise.

15. The nuclear island of claim 6 wherein the active valve of each active IIV is a normally closed valve.

16. The nuclear island of claim 6 wherein the active valve of at least one active IIV is configured to be closed by reactor coolant pressure upon loss of actuator power.

17. A nuclear island comprising:

a nuclear reactor including a nuclear reactor core comprising fissile material disposed in a reactor pressure vessel;

a plurality of auxiliary systems in fluid communication with the nuclear reactor via vessel penetrations wherein each said vessel penetration is either a fluid inlet vessel penetration carrying fluid into the nuclear reactor or a fluid outlet vessel penetration carrying fluid out of the nuclear reactor; and

an integral isolation valve (IIV) system including;

at least one passive IIV comprising a check valve built into a forged flange and not including an actuator, and

at least one active IIV comprising an active valve built into a forged flange and including an actuator,

wherein;

each fluid inlet vessel penetration is protected by a passive IIV whose forged flange is directly connected to the vessel penetration, and

each fluid outlet vessel penetration is protected by an active IIV whose forged flange is directly connected to the vessel penetration.

18. The nuclear island of claim 17 wherein the plurality of auxiliary systems includes an emergency core cooling (ECC) system and a reactor coolant inventory and purification system (RCIPS).

19. The nuclear island of claim 18 wherein the plurality of auxiliary systems further includes a residual heat removal (RHR) system.