Fuel assembly and thimble screw of the same
US7257185B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 30, 2003 |
| Grant date | Aug 14, 2007 |
| Priority date | — |
| Expiry date | Sep 30, 2023 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02E30/30
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
A fuel assembly includes a bottom nozzle set on a lower core plate of a nuclear reactor, a top nozzle with a hold down spring to urge the bottom nozzle against the lower core plate, guide thimbles which guide control rods, having passed through the top nozzle, toward the lower core plate, a dashpot formed on each of the guide thimbles to reduce the fall velocity of a corresponding one of the control rods, a thimble screw which connects each of the guide thimbles to the bottom nozzle, and a drain hole formed to extend through each of the thimble screw. The dashpot has a large-diameter portion with substantially the same diameter as that of each of the guide thimbles. The diameter d of the drain hole falls within a range of 0.04 D<d<0.08 D where D is an inner diameter of the large-diameter portion.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.