US3629067A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Spacer grid for nuclear reactor fuel assembly
Assignee: COMBUSTIBLE NUCLEAIRE
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Filing: 1968-11-08
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Granted: 1971-12-21
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Expires: 1988-11-08
Abstract
Abstract In a nuclear reactor fuel assembly comprising a bundle of rods of fissile or fertile material placed within a casing and supported by two rigid end grids, the rods are maintained at different points between the two end support grids by a spacer grid constituted in accordance with the invention by a frame which surrounds the rods inside the casing and supports at least one layer of parallel helical springs, the turns of said springs being tangent to the rods. Preferably, the layers of springs are four in number, the successive layers being disposed alternately in two directions at right angles to each other whilst the helices of layers having the same direction are relatively displaced by one-half pitch.
Inventors
- 👤 Paul Demaison
- 👤 Pierre Menissier
- 👤 Jean Sionnet
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 10:47
CPC Classifications
G; G21; G21C; G21C3/00; G21C3/30; G21C3/32; G21C3/34; G21C3/3416; Y; Y02; Y02E; Y02E30/00; Y02E30/30
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
80 words
A spacer grid in accordance with claim 1, said springs being disposed in a plurality of spaced superposed layers, the springs of one layer being secured to the same opposite sides of said frame, the springs of the next layer being secured to the other opposite sides of said frame, and the springs of layers secured to the same sides of said frame being displaced by a distance equal to one-half of the pitch of the helix of the springs.
Claim 2
Dependent Claim
20 words
A spacer grid in accordance with claim 1, said frame having lateral openings for the flow of a cooling fluid.
Claim 3
Dependent Claim
33 words
A spaced grid in accordance with claim 1, said frame comprising four perforated plates and rounded corner brackets connecting said plates, said parallel helical springs being secured in opposite ones of said plates.
Claim 4
Dependent Claim
23 words
A spacer grid in accordance with claim 1, having four layers of springs, two of said layers being disposed in each perpendicular direction.
Claim 5
Dependent Claim
27 words
A spacer grid in accordance with claim 5, the helix of each spring having a pitch equal to the distance between the axes of the fuel rods.
Claim 6
Dependent Claim
26 words
A spacer grid in accordance with claim 5, the helix of each spring having a pitch equal to the distance between the axes of adjacent rods.
Claim 7
Dependent Claim
31 words
A spacer grid in accordance with claim 5 each spring being tangent at one point to each fuel rod and the grid being tangent at eight points to each fuel rod.
Claim 8
Dependent Claim
33 words
A spacer grid in accordance with claim 5 each layer of springs being tangent at three points to each fuel rod and the grid being tangent at 12 points to each fuel rod.
Claim 9
Dependent Claim
92 words
A fuel assembly comprising a casing, a bundle of rods of fuel material in said casing, two spaced end grids in said casing supporting said rods, spacer grids within said casing each comprising a perforated frame, a plurality of spaced layers of helical springs supported in said frame perpendicular to said fuel rods and disposed at right angles to each other, the helices of the layers disposed in the same direction being displaced by one-half pitch of the helix and support rods for maintaining said spacer grids in position in said casing.
References Cited (Backward Citations)
US3137638A
Cited
US3380890A
Cited
US3369973A
Cited
US3350275A
Cited
US3378452A
Cited
US3442763A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-12-20 | 1975-06-21 | 1975-12-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-12-20 | 1979-06-21 | 1979-12-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-12-20 | 1983-06-21 | 1983-12-21 | $7700.00 | Window Closed / Lapsed |