Modular Plate and Shell Heat Exchanger for Nuclear Feedwater

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Solution Overview

Problem

Current feedwater heater designs in nuclear power plants face issues with heavy weight, difficulty in design and manufacturing, limited pressure and temperature endurance, and inability to non-destructively disassemble for cleaning, as well as challenges in detecting corrosion/erosion damage and accommodating power uprates without replacing the entire unit.

Innovation Solution

A modular plate and shell feedwater heater design featuring welded heat transfer plate pairs connected via gaskets to header pipes, with a removable head and internal track for easy inspection, repair, and replacement, allowing for incremental uprating by adding more plates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If tube and shell heat exchanger design is used, then pressure endurance is improved, but weight increases significantly

Engineering Contradiction:

Improvepressure enduranceVSAvoidweight

Core Design Contradiction:

StrengthVSWeight of moving object

Solution Approach 1:

The heat exchanger is divided into modular plate packages that can be independently assembled and disassembled. Each plate package contains multiple plates stacked together with seals, forming replaceable modules that can be inserted into or removed from the shell, allowing the heat transfer surface to be upgraded without replacing the entire heavy shell structure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention combines the strength advantages of shell and tube design with the compactness of plate heat exchangers by creating a hybrid structure where plate packages are contained within a shell, utilizing both structural approaches to achieve optimal pressure endurance while reducing overall weight and size.

Inventive Principle:

Principle #40Composite materials

2Weight of moving object

If conventional plate heat exchanger design is used, then weight is reduced, but pressure and temperature endurance deteriorates

Engineering Contradiction:

ImproveweightVSAvoidpressure and temperature endurance

Core Design Contradiction:

Weight of moving objectVSStrength

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Inventive Principle:

Principle #40Composite materials

3Strength

If tube and shell heat exchanger is used, then pressure vessel strength is improved, but design and manufacturing complexity increases

Engineering Contradiction:

Improvepressure vessel strengthVSAvoiddesign and manufacturing complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The plate packages are designed to be dynamically insertable and removable from the shell through opening/closing mechanisms, allowing the system to transition between operational and maintenance states, facilitating easier inspection and repair without complete disassembly of the pressure vessel.

Inventive Principle:

Principle #15Dynamics

4Strength

If welded plate heat exchanger is used, then pressure endurance is improved, but ease of disassembly for cleaning deteriorates

Engineering Contradiction:

Improvepressure enduranceVSAvoidease of disassembly for cleaning

Core Design Contradiction:

StrengthVSEase of operation

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Inventive Principle:

Principle #15Dynamics

5Productivity

If entire heat exchanger is replaced for uprating, then heat transfer capability is improved, but cost and downtime increase

Engineering Contradiction:

Improveheat transfer capabilityVSAvoiddowntime and cost

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The shell structure and associated components are retained and reused, while only the plate packages are replaced or upgraded. This approach recovers the value of the existing shell investment and avoids unnecessary replacement of functional components that are still serviceable.

Inventive Principle:

Principle #34Discarding and recovering

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

Enables long-term sustainable thermal duty, improved component integrity, and increased heat transfer capability without replacing the entire unit, facilitating easier maintenance and uprating while reducing costs and enhancing inspection capabilities.

Implementation Method 1

heat transfer plates welded together to form a heat transfer plate pair

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

The individual heat transfer plates are connected using gaskets to header pipes

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Data Source

PatentUS10175004B2Method of servicing modular plate and shell heat exchanger

Publication Date: 2019.01.08 WESTINGHOUSE ELECTRIC CORP

AI summary

A modular plate and shell heat exchanger in which welded pairs of heat transfer plates are placed in the shell in order to transfer heat from a secondary fluid to a primary fluid. The heat transfer plates are removably connected using gaskets to header pipes which are connected to a primary fluid inlet and a primary fluid outlet nozzle. The header pipes are supported by a structure which rests on an internal track which is attached to the shell and facilitates removal of the heat transfer plates. The modular plate and shell heat exchanger has a removable head integral to the shell for removal of the heat transfer plates for inspection and replacement.