Compact Liquid-Metal Reactor Hydraulic Separation Structure

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Solution Overview

Problem

Existing liquid-metal-cooled nuclear reactors face challenges with the complexity of the primary fluid canalization system and inadequate space utilization, leading to increased reactor vessel diameter and risks such as accidental positive reactivity insertion due to fluid direction reversal and gas entrainment.

Innovation Solution

A compact nuclear reactor design with an amphora-like hydraulic separation structure that integrates pumps and heat exchangers within the cold header, reducing the need for external components and eliminating redundant shielding elements, allowing for vertical fluid feeding and minimizing neutron damage, while maintaining safety through reduced shielding and optimized component placement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If heat exchangers are installed outside the separation structure between hot and cold headers, then the reactor can maintain a simpler internal structure, but the reactor vessel diameter increases due to the circumferential positioning of pump-exchanger units

Engineering Contradiction:

Improveinternal structure complexityVSAvoidreactor vessel diameter

Core Design Contradiction:

Device complexityVSLength of stationary object

Solution Approach 1:

The patent merges the heat exchangers and pump-exchanger units inside the hydraulic separation structure, specifically in the cold header region. This integration eliminates the need for external pump-exchanger units positioned circumferentially, thereby reducing the reactor vessel diameter while maintaining functional complexity at an acceptable level.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The heat exchangers are nested within the hydraulic separation structure, which itself is contained within the reactor vessel. This nested arrangement allows compact positioning of components, reducing the overall footprint and vessel diameter while maintaining all necessary functions.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Length of stationary object

If the separation structure has smaller diameter in upper part and larger diameter in lower part to house pump-exchanger units, then the reactor vessel diameter can be reduced, but the constructional complexity of fluid direction reversal zone increases

Engineering Contradiction:

Improvereactor vessel diameterVSAvoidfluid direction reversal construction

Core Design Contradiction:

Length of stationary objectVSDevice complexity

Solution Approach 1:

Instead of having the separation structure expand upward to accommodate pump-exchanger units, the patent inverts this approach by positioning units in the lower cold header region and maintaining a more uniform or inverted diameter profile, simplifying the upper structure while achieving compactness.

Inventive Principle:

Principle #13The other way round (Inversion)

3Ease of operation

If fluid direction reversal is implemented at the upper edge of the separation structure, then the pump-exchanger units can be fed from above, but the risk of entraining blanket gas increases which could cause accidental positive reactivity insertions

Engineering Contradiction:

Improvefluid feeding convenienceVSAvoidreactor safety

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent inverts the fluid feeding direction by implementing downward flow from the upper hot header through the core to the lower cold header, where pump-exchanger units are positioned. This eliminates the need for upward fluid reversal that could entrain blanket gas, thereby improving safety while maintaining operational convenience through direct gravitational flow.

Inventive Principle:

Principle #13The other way round (Inversion)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This design results in a more compact and economically advantageous reactor with simplified maintenance, reduced downtime, and enhanced safety by eliminating the need for complex fluid direction reversal and shielding, while maintaining effective heat transfer and reducing the risk of reactivity insertion.

Implementation Method 1

heat exchangers (11) through which the primary fluid (8) runs and which transfer the power generated in the core (4) to a secondary fluid circulating in an external secondary circuit

Methodology Applied

Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

pumps (10) and heat exchangers (11) through which the primary fluid (8) runs

Methodology Applied

Scientific EffectPumping: Pump

Data Source

PatentUS10699816B2Nuclear reactor, in particular liquid-metal-cooled compact nuclear reactor

Publication Date: 2020.06.30 NEWCLEO SA

AI summary

The present invention relates to a nuclear reactor (1), in particular a liquid-metal-cooled reactor, provided with a separation structure (5) between hot header (6) and cold header (7), narrower in the upper portion (16) for containment of the headers of the fuel assemblies and wider in the lower element (14) at the active part (4) of the core, with a variously shaped connecting element (15) between the lower element (14) and the upper element (16), and with heat exchangers (11) positioned between the upper portion (16) of said separation structure (5) and the reactor vessel (2), which engage on the connecting element (15) via vertical ducts (20) for being fed with hot primary fluid leaving the core (4).