US4229256A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Corrugated thimble tube for controlling control rod descent in nuclear reactor
Assignee: Honeywell UOP LLC
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Filing: 1977-12-28
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Granted: 1980-10-21
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Expires: 1997-12-28
Abstract
Abstract Improved shock absorber for slowing down the descent of a control rod in a liquid cooled reactor core at a controlled rate uses a thimble tube which has a corrugated section at its lower end to distribute the control rod deceleration forces over an extended distance in a "scram" situation. In a preferred embodiment, the corrugations have a lesser internal diameter at the lower end of the thimble tube than at the top to increase the rate of deceleration as the control rod aproaches the bottom of the core. In several modifications, the corrugation pitch and/or depth is varied over the length of the corrugated surface.
Inventors
- 👤 Howard J. Luetzow
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 12:12
CPC Classifications
G; G21; G21C; G21C7/00; G21C7/06; G21C7/08; G21C7/20; Y; Y02; Y02E; Y02E30/00; Y02E30/30
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
144 words
In a shock absorber for a control rod used in a nuclear reactor cooled by liquid, the improvement comprising a guide or thimble tube for said control rod, said thimble tube being internally helically corrugated along at least one extended axial portion near its lower end, said helically corrugated portion having internal diameters of smaller distance at the lower end than at the upper end of said corrugated portion and a progressively smaller pitch of corrugation from the top to the bottom of said corrugated portion and cooperating with the outer wall portion of the lower end of said control rod to brake the descent of said control rod with progressively increasing hydraulic restraining force provided by the liquid coolant in the annular space between the thimble or guide tube and said control rod as each adjacent progressively smaller section of corrugation is encountered.
Claim 2
Dependent Claim
144 words
In a shock absorber for a control rod used in a nuclear reactor cooled by liquid, the improvement comprising a guide or thimble tube for said control rod, said thimble tube being internally helically corrugated along at least one extended axial portion near its lower end, said helically corrugated portion having internal diameters of smaller distance at the lower end than at the upper end of said corrugated portion and a progressively smaller pitch of corrugation from the top to the bottom of said corrugated portion and cooperating with the outer wall portion of the lower end of said control rod to brake the descent of said control rod with progressively increasing hydraulic restraining force provided by the liquid coolant in the annular space between the thimble or guide tube and said control rod as each adjacent progressively smaller section of corrugation is encountered.
Claim 3
Dependent Claim
33 words
The shock absorber of claim 1 wherein said thimble tube includes a plurality of helically corrugated portions spaced by smooth portions having a greater internal diameter than that of either adjacent corrugated portion.
References Cited (Backward Citations)
FR1120705A
Cited
FR1352881A
Cited
US3301140A
Cited
FR1451407A
Cited
FR95560E
Cited
DE1250020B
Cited
US3562109A
Cited
US3628638A
Cited
US3855060A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-10-21 | 1984-04-21 | 1984-10-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-10-21 | 1988-04-21 | 1988-10-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-10-21 | 1992-04-21 | 1992-10-21 | $7700.00 | Window Closed / Lapsed |