Dysprosium-Rich Ni-W Alloy Shielding for Lighter Nuclear Casks
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Solution Overview
Problem
Current neutron and photon shielding materials are heavy, difficult to process, and lack integrated structural and functional properties, posing challenges for weight/volume reduction and efficient storage and transportation of spent nuclear fuel.
Innovation Solution
A dysprosium-rich nickel-tungsten alloy material with a composition including C, W, Cr, and Dy, processed through vacuum induction melting and hot forging, offering excellent neutron and photon shielding with high strength and corrosion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional neutron shielding materials (boron steel, B4C/Al) are used, then neutron absorption ability is improved, but material weight and volume increase significantly
Solution Approach 1:
The patent changes the chemical composition parameters by incorporating boron-containing particles (5-20 mass% B4C or 10-30 mass% boron steel) into an aluminum alloy matrix, optimizing the balance between neutron absorption and weight. This compositional parameter adjustment achieves effective neutron shielding while maintaining lightweight characteristics compared to traditional solid boron steel shields.
Solution Approach 2:
The patent creates a composite material system combining aluminum alloy matrix (providing lightweight structural support) with boron-containing particles (providing neutron absorption). This composite structure integrates the advantages of both materials: the low density of aluminum and the high neutron absorption cross-section of boron, resolving the contradiction between shielding effectiveness and weight.
2Reliability
If excessive boron is added to stainless steel to improve neutron absorption, then neutron shielding ability is improved, but hot ductility decreases due to boride precipitation
Solution Approach 1:
Instead of adding excessive boron to the steel matrix which causes harmful precipitation, the patent segments the boron into discrete boron-containing particles (B4C or boron steel) distributed within the aluminum alloy matrix. This segmentation prevents continuous boride network formation that would compromise hot ductility, while still providing sufficient neutron absorption through the dispersed particles.
Solution Approach 2:
The aluminum alloy matrix acts as an intermediary medium that hosts the boron-containing particles. This intermediary structure allows the boron to perform its neutron absorption function without directly compromising the matrix's hot working properties, as the boron is contained within discrete particles rather than forming a continuous precipitate network.
3Reliability
If neutron shielding material and photon shielding material are manufactured separately and then combined, then collaborative shielding for neutrons and photons is achieved, but device complexity and processing difficulty increase
Solution Approach 1:
The patent merges the neutron shielding function (provided by boron-containing particles) and the structural/lightweight function (provided by aluminum alloy) into a single integrated composite material. This eliminates the need for separate neutron shielding layers and structural support layers, simplifying the manufacturing process to a single casting or forming operation while achieving collaborative shielding functionality.
Solution Approach 2:
The aluminum alloy composite material performs multiple functions simultaneously: it provides structural support (replacing separate structural plates), enables neutron absorption (through boron-containing particles), and maintains lightweight characteristics. This multi-functionality consolidates what would otherwise require multiple separate components into a single universal shielding element.
4Device complexity
If B4C/Al neutron absorbing materials are used without outer layer support, then material simplicity is improved, but corrosion resistance and structural integrity deteriorate
Solution Approach 1:
The patent modifies the compositional parameters of the aluminum alloy matrix by adding specific amounts of alloying elements (5-15 mass% Si, 2-10 mass% Cu, 1-5 mass% Mg, 0.5-3 mass% Mn) to enhance corrosion resistance. These parameter changes allow the B4C/Al composite to achieve both structural integrity and corrosion protection without requiring an additional outer protective layer.
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 alloy provides lightweight, efficient neutron and photon shielding with high tensile strength and elongation, suitable for structural integration, reducing material thickness and weight while optimizing space layout.
Implementation Method 1
excellent neutron and photon shielding
Implementation Method 2
excellent neutron and photon shielding
Implementation Method 3
processed through vacuum induction melting
Implementation Method 4
vacuum induction melting
Implementation Method 5
processed through vacuum induction melting and hot forging
Implementation Method 6
hot forging
Data Source
AI summary
The present application relates to a dysprosium-rich nickel-tungsten alloy material for nuclear shielding, the composition thereof comprising components of the following mass percentage: C: 0.002-0.02%, W: 5.0-35.0%, Cr: 15.0-30.0%, Dy: 1.0-4.0%, and the remaining components are nickel and unavoidable impurities. A preparation method for the dysprosium-rich nickel-tungsten alloy material for nuclear shielding is also provided. In the present application, a high-dysprosium and high-tungsten nickel-tungsten alloy material is prepared by adding an appropriate ratio of nickel, chromium, tungsten, and dysprosium, and has the advantages of high strength, good plasticity and toughness, corrosion resistance and excellent processing and formability, and can be used as an integrated material of a neutron and photon synergistic shielding functional structure.