Integral isolation valve systems for loss of coolant accident protection

Patent metadata

Field	Value
Publication number	US-10529458-B2
Application number	US-201414337268-A
Country	US
Kind code	B2
Filing date	Jul 22, 2014
Priority date	Jul 22, 2014
Publication date	Jan 7, 2020
Grant date	Jan 7, 2020

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.

First claim

The claims are as follows:

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 reactor pressure vessel through an ECC pressure vessel feedthrough;
a reactor coolant inventory and purification system (RCIPS) connected to the reactor pressure vessel to inject coolant into the reactor pressure vessel through a make-up line connected to a make-up line pressure vessel feedthrough and to extract coolant from the reactor pressure vessel through a let-down line connected to a let-down line pressure 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 pressure vessel feedthrough and a corresponding ECC system line,
a passive IIV comprising a check valve built into a forged flange that is connected directly to the make-up line pressure vessel feedthrough and the make-up line, and
an active IIV comprising an active valve built into a forged flange that is connected directly to the let-down line pressure vessel feedthrough and the let-down line,
wherein the passive and active IIVs each have an outer diameter along its entire length that is greater than an outer diameter of the corresponding ECC system line, make-up line, and let-down line to which it is connected.

2. The nuclear island of claim 1 further comprising:
a residual heat removal (RHR) system having an RHR inlet line connected to the reactor pressure vessel through an RHR pressure vessel inlet feedthrough and an RHR outlet line connected to the reactor pressure vessel through an RHR pressure vessel outlet 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 pressure vessel outlet feedthrough and the RHR outline line, and
an active IIV comprising an active valve built into a forged flange that is connected directly to the RHR pressure vessel inlet feedthrough and the RHR inlet line,
wherein the passive and active IIVs each have an outer diameter along its entire length that is greater than an outer diameter of the corresponding RHR outlet line and RHR inlet line, respectively, to which it is connected.

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 pressure vessel inlet 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 pressure 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 pressure vessel penetrations that exclusively carry flow into the reactor pressure vessel and at least one pressure vessel penetration that carries flow out of the reactor pressure vessel; 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 pressure vessel penetration that exclusively carries flow into the reactor pressure vessel is protected by a passive IIV whose forged flange is directly connected to the corresponding pressure vessel penetration and a corresponding line, and
each pressure vessel penetration that carries flow out of the reactor pressure vessel is protected by an active IIV whose forged flange is directly connected to the corresponding pressure vessel penetration and a corresponding line,
wherein the passive and active IIVs each have an outer diameter along its entire length that is greater than an outer diameter of the corresponding line to which it is connected.

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

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 reactor pressure vessel through a pressure vessel penetration that exclusively carries flow into the reactor pressure vessel and is protected by a passive IIV whose forged flange is directly connected to the pressure vessel penetration and a corresponding ECC system line,
wherein the passive IIV has an outer diameter that is greater along its entire length than an outer diameter of the corresponding ECC system line to which it is connected.

10. The nuclear island of claim 6 further comprising:
a reactor coolant inventory and purification system (RCIPS) connected to the reactor pressure vessel to inject coolant into the reactor pressure vessel through a vessel penetration that exclusively carries flow into the reactor pressure vessel and is protected by a passive IIV whose forged flange is directly connected to the pressure vessel penetration and a corresponding RCIPS line,
wherein the passive IIV has an outer diameter that is great along its entire length than an outer diameter of the corresponding RCIPS line to which it is connected.

11. The nuclear island of claim 10 wherein the RCIPS is further connected to the reactor pressure vessel to extract coolant from the reactor pressure vessel through a pressure vessel penetration that exclusively carries flow out of the reactor pressure vessel and is protected by an active IIV whose forged flange is directly connected to the pressure vessel penetration and a corresponding RCIPS line,
wherein the active IIV has an outer diameter that is greater along its entire length than an outer diameter of the corresponding RCIPS line to which it is connected.

12. The nuclear island of claim 11 further comprising:
a residual heat removal (RHR) system having:
an inlet line connected to the reactor pressure vessel through a pressure vessel penetration that exclusively carries flow out of the reactor pressure vessel and is protected by an active IIV whose forged flange is directly connected to the pressure vessel penetration and the inlet line, and
an outlet line connected to the reactor pressure vessel through a pressure vessel penetration that exclusively carries flow into the reactor pressure vessel and is protected by a passive IIV whose forged flange is directly connected to the pressure vessel penetration and the outlet line,
wherein the passive and active IIVs each have an outer diameter that is greater along its entire length than an outer diameter of the corresponding outlet line and inlet line, respectively, to which it is connected.

13. The nuclear island of claim 6 further comprising:
a residual heat removal (RHR) system having:
an inlet line connected t

Assignees

• Bwxt Mpower Inc

Inventors

• Kanuch David J
• Difilipo Paul P

Classifications

• G21C19/30

  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 title

• G21C15/182 Primary

  comprising powered means, e.g. pumps · CPC title

• G21C15/18

  Emergency cooling arrangements; Removing shut-down heat · CPC title

• G21C9/00 Primary

  Emergency protection arrangements structurally associated with the reactor {, e.g. safety valves provided with pressure equalisation devices}(emergency cooling arrangements G21C15/18) · CPC title

• G21C13/02

  Details · CPC title