Vented Nuclear Fission Fuel Module for Cladding Corrosion Control

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Solution Overview

Problem

Nuclear fission reactors face challenges with fuel rod swelling, cracking, and rupture due to the accumulation of fission product solids and gases, which can lead to cladding corrosion, stress concentrations, and uncontrolled release of fission products into the primary coolant system, necessitating premature reactor shutdowns and design life reductions.

Innovation Solution

A vented nuclear fission fuel module system that includes a valve body with a plenum for receiving gaseous fission products and a controllable valve for venting these products into the reactor vessel, utilizing a flexible diaphragm and removable cap to manage pressure and prevent backflow, along with sensors for monitoring fission product pressure and type, ensuring controlled release and minimizing contamination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If fission products are retained in the fuel rod to maintain fuel integrity, then fuel rod swelling and cracking increase, but reactor operational life decreases due to premature shutdowns

Engineering Contradiction:
Improvefuel rod integrityVSAvoidreactor operational life
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent extracts gaseous fission products from the fuel rod by venting them through a valve mechanism into a separate plenum chamber, removing the harmful accumulation that causes swelling and cracking while preserving fuel rod structural integrity

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The fuel rod system is segmented into separate functional zones: a sealed fuel pellet region and a vented plenum chamber, allowing fission products to be isolated and managed separately from the fuel structure to extend reactor operational life

Inventive Principle:
Principle #1Segmentation

2Reliability

If a venting system is added to remove fission products, then fuel rod swelling and cracking are reduced, but device complexity increases

Engineering Contradiction:
Improvefuel rod integrityVSAvoidventing system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The venting valve, plenum chamber, and sensor systems are merged into an integrated assembly that is coupled to the fuel rod, consolidating multiple functions into a single coordinated system rather than separate components

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system uses sensors to automatically detect fission product pressure and triggers automatic valve actuation, enabling the venting system to operate autonomously without external control intervention, thereby managing complexity through self-regulation

Inventive Principle:
Principle #25Self-service

3Stress or pressure

If fission products are vented into the primary coolant system, then pressure is relieved from the fuel rod, but cladding corrosion and contamination increase

Engineering Contradiction:
Improveinternal fuel rod pressureVSAvoidcladding corrosion
Core Design Contradiction:
Stress or pressureVSObject-affected harmful factors

Solution Approach 1:

The plenum chamber serves as an intermediary between the fuel rod interior and the primary coolant system, providing a controlled interface that allows pressure relief while preventing direct contact between fission products and the coolant that would cause corrosion and contamination

Inventive Principle:
Principle #24Intermediary (Mediator)

4Stress or pressure

If the venting valve is always open to release pressure, then fission product accumulation is prevented, but uncontrolled release and contamination occur

Engineering Contradiction:
Improvefission gas pressureVSAvoiduncontrolled fission product release
Core Design Contradiction:
Stress or pressureVSObject-generated harmful factors

Solution Approach 1:

Sensors continuously monitor fission product pressure within the fuel rod and provide feedback signals that trigger automatic valve actuation when pressure thresholds are exceeded, enabling controlled pressure relief rather than constant venting

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The valve transitions from a static closed state to a dynamic controlled state, opening only when sensor feedback indicates the need for pressure relief and closing when pressure is normalized, adapting to changing operational conditions

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

The system effectively reduces the risk of fuel rod swelling and cracking, prevents cladding corrosion, and allows for controlled venting of fission products, thereby extending reactor life and maintaining operational safety by managing fission gas pressure and preventing uncontrolled releases.

Implementation Method 1

a flexible diaphragm and removable cap to manage pressure

Methodology Applied
Scientific EffectPressure: Pressure Increase

Data Source

PatentEP2471071B1A vented nuclear fission fuel module
Publication Date: 2019.11.13 TERRAPOWER LLC
  • EP2471071B1 patent drawingFigure 1
  • EP2471071B1 patent drawingFigure 2
  • EP2471071B1 patent drawingFigure 3

AI summary

Illustrative embodiments provide a nuclear fission reactor, a vented nuclear fission fuel module, methods therefor and a vented nuclear fission fuel module system.