Floating Cooling Module for Nuclear Fuel Pool Heat Transfer

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Solution Overview

Problem

Conventional nuclear fuel pool cooling systems face challenges in maintaining reliable heat transfer during reduced water levels, which can lead to increased water temperatures and potential nuclear meltdown, especially under seismic loads and in existing facilities where space is limited.

Innovation Solution

A floating cooling module with a lifting body that adjusts its altitude with the liquid level, ensuring the heat exchanger remains submerged and maintaining a consistent water column height, eliminating the need for bulky support structures and allowing for easy retrofitting or use in new constructions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional fixed cooling elements are used, then the cooling system can maintain stable heat transfer under normal conditions, but the heat transfer power reduces when water level drops due to evaporation or leakage

Engineering Contradiction:

Improveheat transfer reliabilityVSAvoidadaptability to water level changes

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The cooling element is made dynamically adaptable to water level changes through a floating support mechanism. The support structure includes a floating body that automatically adjusts the vertical position of the cooling element as water level fluctuates, ensuring the cooling element remains fully submerged and maintains optimal heat transfer performance throughout the entire operating range.

Inventive Principle:

Principle #15Dynamics

2Strength

If large support constructions are used to withstand seismic loads, then the cooling system can resist seismic forces, but the required installation space increases which is not available in existing plants

Engineering Contradiction:

Improveseismic load resistanceVSAvoidinstallation space

Core Design Contradiction:

StrengthVSArea of stationary object

Solution Approach 1:

The support construction utilizes the buoyant force of water as a counterweight to seismic loads. The floating support structure leverages the displacement of water to generate upward buoyant forces that counterbalance the weight and inertial forces of the cooling element during seismic events, achieving seismic resistance with a compact design that fits within existing plant spaces.

Inventive Principle:

Principle #8Anti-weight (Counterweight)

Solution Approach 2:

The support system employs hydraulic principles through the floating mechanism, where the buoyant force generated by water displacement provides the primary support and shock-absorbing capability. The water itself acts as both the cooling medium and the structural support medium, eliminating the need for separate large-scale mechanical support structures.

Inventive Principle:

Principle #29Pneumatics and hydraulics

3Ease of manufacture

If fixed cooling elements are positioned at high locations in the building, then the cooling system can be installed in existing facilities, but the cooling elements are more vulnerable to reduced water levels and seismic loads

Engineering Contradiction:

Improveinstallation feasibility in existing facilitiesVSAvoidcooling reliability under accident conditions

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The cooling element transitions from a fixed position to a dynamically adjustable position through the floating support mechanism. This allows the cooling element to automatically lower itself when water levels drop or when subjected to seismic forces, maintaining its functional submersion depth and cooling effectiveness regardless of the pool's initial filling level or external disturbances.

Inventive Principle:

Principle #15Dynamics

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 solution ensures continuous and efficient heat removal at varying liquid levels, preventing fuel rod exposure to air and reducing the risk of nuclear meltdown, while minimizing seismic displacement and impact on the pool lining, and can be easily integrated into existing facilities.

Implementation Method 1

The cooling module (14) contains a lifting body (16) and floats in the liquid (4) such that its altitude varies passively with the filling level (6) of the liquid (4) in the fuel pool (2)

Methodology Applied

Scientific EffectBuoyancy: Archimedes' Principle (Buoyancy)

Implementation Method 2

The cooling module (14) contains a heat exchanger (18) whose heat transfer surface is covered with the liquid (4)

Methodology Applied

Scientific EffectHeat transfer: Heat Exchanger

Data Source

PatentUS11257601B2Nuclear facility with a fuel pool and an associated cooling module

Publication Date: 2022.02.22 FRAMATOME GMBH

AI summary

A nuclear facility has a fuel pool containing a liquid and an associated cooling circuit for a circulating cooling agent. The cooling circuit contains a cooling module with a first heat exchanger which immerges into the liquid, a second heat exchanger which is located outside the fuel pool, and connecting lines between the first exchanger and the second heat exchanger. In order to provide for reliable cooling even if a filling level drops, the cooling module contains a lifting body and floats in the liquid such that its altitude varies with the filling level of the liquid in the fuel pool.