# US 2018/0322966 A1 · Very simplified boiling water reactors for commercial electricity generation

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- Number: US 2018/0322966 A1
- Document ID: US20180322966A1
- Status: Published application
- Kind: A1
- Application number: 15/585,162
- Filed: 2017-05-02
- Published: 2018-11-08
- Earliest claimed: 2017-05-02
- Assignees: GE-Hitachi Nuclear Energy Americas LLC
- Applicants: GE-Hitachi Nuclear Energy Americas LLC
- Inventors: Brian S. Hunt; Christer N. Dahlgren; Wayne Marquino
- Web page: https://patentgrep.com/patent/US20180322966A1

## CPC

- G21C 9/004: Pressure suppression
- G21C 1/028: {cooled by a pressurised coolant (cooling arrangements G21C15/00)}
- G21C 1/086: {Pressurised water reactors}
- G21C 9/016: Core catchers
- G21C 13/02: Details
- G21C 13/028: Seals, e.g. for pressure vessels or containment vessels
- G21C 15/18: Emergency cooling arrangements; Removing shut-down heat
- G21C 9/033: by an absorbent fluid
- G21C 13/087: Metallic vessels
- G21C 13/093: Concrete vessels
- G21C 17/042: {Devices for selective sampling, e.g. valves, shutters, rotatable selector valves}
- Y02E 30/00: Energy generation of nuclear origin
- Y02E 30/30: Nuclear fission reactors
- G21C: NUCLEAR REACTORS (fusion reactors, hybrid fission-fusion reactors G21B; nuclear explosives G21J)
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

Nuclear reactors have very few systems for significantly reduced failure possibilities. Nuclear reactors may be boiling water reactors with natural circulation-enabling heights and smaller, flexible energy outputs in the 0-350 megawatt-electric range. Reactors are fully surrounded by an impermeable, high-pressure containment. No coolant pools, heat sinks, active pumps, or other emergency fluid sources may be present inside containment; emergency cooling, like isolation condenser systems, are outside containment. Isolation valves integral with the reactor pressure vessel provide working and emergency fluid through containment to the reactor. Isolation valves are one-piece, welded, or otherwise integral with reactors and fluid conduits having ASME-compliance to eliminate risk of shear failure. Containment may be completely underground and seismically insulated to minimize footprint and above-ground target area.

## Claims

### Claim 1

A simplified nuclear reactor system for commercially generating electricity, the system comprising:
a nuclear reactor;
at least one primary coolant loop connecting to the nuclear reactor; and
at least one emergency coolant source connecting to the nuclear reactor, wherein the nuclear reactor is integrally isolatable from the primary coolant loop and the emergency coolant source.

### Claim 2 (depends on 1)

The system of claim 1, further comprising:
a containment, wherein the reactor is inside the containment, wherein the emergency coolant source is outside containment, and wherein the containment is entirely underground.

### Claim 3 (depends on 2)

The system of claim 2, wherein the containment has a personnel access point at a top shield accessible from ground.

### Claim 4 (depends on 2)

The system of claim 2, wherein the nuclear reactor is a maximum 1000 megawatt-thermal rated boiling water reactor having a height that exceeds its width by a factor of at least 3.9.

### Claim 5 (depends on 2)

The system of claim 2, wherein the containment does not include any open coolant pool for emergency cooling.

### Claim 6 (depends on 1)

The system of claim 1, further comprising:
a plurality of isolation valves connecting the primary coolant loop and the emergency coolant source to the nuclear reactor, wherein each of the isolation valves includes a primary and a secondary actuator, and wherein each of the isolation valves is integral with the nuclear reactor and is connected to one of the primary coolant loop and the emergency coolant source.

### Claim 7 (depends on 6)

The system of claim 6, further comprising:
a containment surrounding the nuclear reactor, wherein each of the isolation valves connected to the one of the primary coolant loop and the emergency coolant source outside of the containment; and
a plurality of penetration seals, wherein each one of the penetration seals lines and seals the containment at each one of the isolation valves.

### Claim 8 (depends on 7)

The system of claim 7, wherein all penetrations that move a fluid coolant to or from the reactor include at least one of the isolation valves, and wherein the containment is fluid-tight up to 300 psig.

### Claim 9 (depends on 1)

The system of claim 1, further comprising:
a containment; and
a silo surrounding the containment and the emergency coolant source, wherein the silo is a seismic structure configured to reduce seismic shocks to the containment, the emergency coolant source, and the nuclear reactor.

### Claim 10

A simplified nuclear reactor facility for commercially generating electricity, the facility comprising:
a nuclear reactor;
a containment completely and impermeably surrounding the nuclear reactor, wherein there is no open coolant source or active coolant pump inside the containment;
at least one primary coolant loop connecting to the nuclear reactor through the containment; and
at least one emergency coolant source outside the containment and connecting to the nuclear reactor through the containment.

### Claim 11 (depends on 10)

The facility of claim 10, wherein the emergency coolant source is an isolation condenser system with a pool configured to condense a coolant of the nuclear reactor and transfer heat from the nuclear reactor to ambient environment.

### Claim 12 (depends on 11)

The facility of claim 11, wherein the isolation condenser and the primary coolant loop each join to two of a plurality of isolation valves of the nuclear reactor at the containment.

### Claim 13 (depends on 12)

The facility of claim 12, wherein each of the isolation valves includes a primary and a secondary actuator, wherein each of the isolation valves is integral with the nuclear reactor, and wherein each of the isolation valves is configured to be passively opened and passively sealed.

### Claim 14 (depends on 13)

The facility of claim 13, wherein the isolation condenser joins to isolation valves configured to fail open or open at detection of a transient event, and wherein the primary coolant loop joins to isolation valves configured to fail closed or close at detection of the transient event.

### Claim 15 (depends on 13)

The facility of claim 13, further comprising:
a plurality of penetration seals, wherein each one of the penetration seals lines and seals the containment at each one of the isolation valves.

### Claim 16 (depends on 15)

The facility of claim 15, wherein all penetrations that move a fluid coolant to or from the reactor include at least one of the isolation valves, and wherein the containment is fluid-tight up to 300 psig.

### Claim 17 (depends on 13)

The facility of claim 13, wherein the nuclear reactor is a maximum 1000 megawatt-thermal rated boiling water reactor having a height that exceeds its width by a factor of at least 3.9.

### Claim 18 (depends on 13)

The facility of claim 13, wherein the containment is entirely underground.

### Claim 19 (depends on 13)

The facility of claim 13, further comprising:
a silo surrounding the containment and the emergency coolant source, wherein the silo is a seismic structure configured to reduce seismic shocks to the containment, the emergency coolant source, and the nuclear reactor.

### Claim 20

A nuclear reactor power plant for commercially generating electricity, the plant comprising:
a maximum 1000 megawatt-thermal rated boiling water nuclear reactor having a height that exceeds its width by a factor of at least 3.9;
a containment completely and impermeably surrounding the nuclear reactor, wherein there is no open coolant source or active pump inside the containment, and wherein the containment is completely underground;
at least one primary coolant loop connecting to the nuclear reactor through the containment;
at least one emergency coolant source outside the containment and connecting to the nuclear reactor through the containment, wherein the primary coolant loop and the emergency coolant source are integral with the nuclear reactor inside containment;
a plurality of isolation valves connecting the primary coolant loop and the emergency coolant source to the nuclear reactor through the containment, wherein each of the isolation valves includes a primary and a secondary actuator, and wherein each of the isolation valves is integral with the nuclear reactor;
a plurality of penetration seals, wherein each one of the penetration seals lines and seals the containment at each one of the isolation valves; and
a silo surrounding the containment and the emergency coolant source, wherein the silo is a seismic structure configured to reduce seismic shocks to the containment, the emergency coolant source, and the nuclear reactor.