Jacketless Fuel Assembly with Spiral Ribs for PWRs
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current nuclear reactor designs using thorium as fuel are not fully nonproliferative, as they produce higher-than-minimum quantities of proliferative plutonium and are not optimized for operational parameters, leading to inefficient use of nonproliferative enriched uranium and unsuitable for consuming large amounts of plutonium, and are not compatible with existing light water reactors like the VVER-1000.
Innovation Solution
A fuel assembly design for light water reactors featuring a hexagonal seed subassembly with enriched uranium or reactor-grade plutonium, surrounded by a thorium-based blanket subassembly, optimized moderator-to-fuel volume ratios, and a zirconium alloy cladding with a three-lobed profile forming spiral spacer ribs, allowing for efficient power generation without producing proliferative wastes and compatible with existing reactor designs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If seed-blanket reactors with circular seed zone and inner/outer blanket zones are used, then thorium fuel utilization is improved, but proliferative plutonium production increases beyond minimum levels
Solution Approach 1:
The fuel assembly is divided into a seed subassembly containing enriched uranium or reactor-grade plutonium and a blanket subassembly containing thorium, replacing the circular seed zone design with a modular seed-blanket configuration that optimizes neutron economy and minimizes plutonium production while maintaining thorium utilization
Solution Approach 2:
The invention changes the geometric parameters from a circular seed zone with annular blankets to a hexagonal fuel assembly with specific seed-to-blanket ratios and configurations, optimizing the neutron spectrum and moderation to minimize plutonium production while maintaining efficient thorium fuel utilization
2Ease of operation
If conventional reactor designs are used, then operational simplicity is maintained, but large amounts of proliferative plutonium are created requiring security measures
Solution Approach 1:
The invention modifies key operational parameters including moderator-to-fuel volume ratios, fuel composition (using thorium and nonproliferative enriched uranium), and fuel assembly geometry to fundamentally change the neutron economy and minimize plutonium production while maintaining operational simplicity compatible with existing light water reactors
3Object-generated harmful factors
If seed-blanket reactors with optimized moderator ratios are used, then plutonium production is minimized, but compatibility with existing light water reactors like VVER-1000 is reduced
Solution Approach 1:
The fuel assembly design incorporates universal features including standard hexagonal geometry, compatible dimensions and pitch, and adaptability to existing control rod mechanisms, allowing the same design to be installed in existing light water reactors like VVER-1000 while maintaining optimized moderator-to-fuel ratios that minimize plutonium production
4Object-generated harmful factors
If nonproliferative enriched uranium is used as seed fuel, then weapons-grade plutonium production is reduced, but the fuel is not fully consumed requiring reprocessing
Solution Approach 1:
The invention optimizes the seed fuel composition and enrichment level, and adjusts the seed-to-blanket fuel ratio to maximize the consumption of nonproliferative enriched uranium through enhanced neutron economy and extended burnup, reducing the need for reprocessing while maintaining nonproliferation goals
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 design significantly reduces the production of proliferative wastes, optimizes the use of nonproliferative uranium, and allows for the consumption of large amounts of plutonium, while being mechanically and hydraulically compatible with existing reactors, thus enhancing safety and operational efficiency.
Implementation Method 1
a kernel (14) comprising fissionable material
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to light water reactor designs in which thorium is used as fuel and in particular to designs of jacketless fuel assemblies, which make up the cores of pressurized water reactors (PWRs) such as the VVER-1000. A fuel element is provided for use in a fuel assembly of a nuclear reactor, the fuel element comprising a kernel comprising fissionable material, wherein the fuel element has a multi-lobed profile that forms spiral ribs.