Neutron Source Target Layer Hydrogen Embrittlement Prevention

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Solution Overview

Problem

Existing small neutron sources face challenges with hydrogen embrittlement, leading to target degradation and limited operational time due to blistering, especially when using low-energy proton beams, and existing solutions either partially address the issue or are not applicable for all energy levels.

Innovation Solution

A neutron source design incorporating a support layer with a high hydrogen diffusion coefficient metal element, such as Vanadium, that rapidly diffuses and discharges generated hydrogen, combined with a target layer capable of producing neutrons using low-energy proton beams, to prevent hydrogen embrittlement and enhance mechanical strength, allowing for long-term continuous operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If low energy proton beams are used to produce neutron beams, then the facility size can be reduced and handling becomes easier, but the target suffers from hydrogen embrittlement and blistering

Engineering Contradiction:
Improvefacility sizeVSAvoidtarget durability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The target is divided into multiple layers: a neutron-producing material layer (Be or Li) and a support layer containing hydrogen-absorbing metal elements (V, Nb, Ta). This segmentation allows the neutron production function and hydrogen management function to be separated, enabling low-energy proton beam operation without blistering.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Hydrogen-absorbing metal elements (V, Nb, Ta) are introduced as intermediary substances in the support layer. These materials absorb excess hydrogen generated during low-energy proton irradiation, preventing hydrogen accumulation and blistering in the neutron-producing material layer.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a Pd film is used to absorb hydrogen, then hydrogen embrittlement is prevented, but the film thickness must be sufficient to ensure effectiveness

Engineering Contradiction:
Improvehydrogen embrittlement preventionVSAvoidfilm thickness
Core Design Contradiction:
ReliabilityVSLength of stationary object

Solution Approach 1:

The invention changes the material parameter of the hydrogen-absorbing layer from Pd (with specific diffusion properties) to hydrogen-absorbing metal elements (V, Nb, Ta) with different diffusion coefficients. This parameter change allows effective hydrogen management with optimized layer thickness, balancing effectiveness and structural considerations.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If the neutron-producing material layer is made thicker, then neutron production efficiency increases, but hydrogen accumulation and blistering risk increase

Engineering Contradiction:
Improveneutron production efficiencyVSAvoidhydrogen accumulation
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The target structure is segmented into a neutron-producing material layer and a support layer with hydrogen-absorbing capabilities. This segmentation allows the neutron-producing layer to be optimized for thickness without compromising the system, as the support layer handles hydrogen removal independently.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The support layer with hydrogen-absorbing metal elements acts as an intermediary that captures hydrogen before it accumulates in the neutron-producing material layer. This enables thicker neutron-producing layers to be used for higher efficiency without increasing blistering risk.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 solution effectively prevents hydrogen embrittlement, maintains neutron generation efficiency, and reduces radioactivity, enabling safe and durable operation of the neutron source for extended periods with easy maintenance, making it suitable for small facilities.

Implementation Method 1

a support layer with a high hydrogen diffusion coefficient metal element, such as Vanadium, that rapidly diffuses and discharges generated hydrogen

Methodology Applied
Scientific EffectDiffusion: Diffusion

Implementation Method 2

neutrons are produced by irradiating a target (e.g., Be, Li, or the like) with proton beams to thereby cause a nuclear reaction

Methodology Applied
Scientific EffectNuclear reaction: Nuclear Fission

Data Source

PatentEP2824999B1Neutron generation source, and neutron generation device
Publication Date: 2020.05.06 RIKEN CO LTD
  • EP2824999B1 patent drawingFigure 1
  • EP2824999B1 patent drawingFigure 2(a)~2(b)
  • EP2824999B1 patent drawingFigure 3(a)~3(b)

AI summary

The present invention provides a novel neutron source. A neutron source (1) of the present invention includes a neutron producing material layer (3) and a metal layer (2), and the metal layer (2) contains a metal element which has a high hydrogen diffusivity and generates radionuclides having a short half-life upon receipt of irradiation of neutron beams.