US3772148A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Nuclear reactor fuel element spacer grid
Assignee: United Kingdom Atomic Energy Authority
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Filing: 1970-08-25
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Granted: 1973-11-13
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Expires: 1990-08-25
Abstract
Abstract A spacer grid for a nuclear reactor fuel assembly is of cellular form being constructed, for example, from two superimposed layers of cojoined tubular ferrules. Each of the fuel pins passes through a corresponding pair of ferrules in the two layers. Two circumferentially spaced rigid support members extend into one of each pair of ferrules and a single rigid support member extends into the other of the pair of ferrules. The fuel pin extending through each pair of ferrules contacts the rigid support members therein, the rigid support members being positioned at points on the corner of a triangle and the fuel pin being biassed into contact with the support members by a bow spring extending between the pair of ferrules.
Inventors
- 👤 T Seddon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 20:49
CPC Classifications
G; G21; G21C; G21C3/00; G21C3/30; G21C3/32; G21C3/34; G21C3/344; G21C3/356; Y; Y02; Y02E; Y02E30/00; Y02E30/30
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
196 words
A spacer grid for a nuclear reactor fuel assembly including a plurality of elongate fuel pins supported in a bundle with their longitudinal axes parallel, said spacer grid being of cellular form having openings through which the fuel pins will extend, no more than three substantially rigid support members extending into each of said openings and circumferentially spaced about said opening, resilient means being provided in each opening so as to be on a side of a single fuel pin in opposed relationship with said three support members and located to contact and bias said single fuel pin in the opening against the three support members, said support members being positioned so that a single port member will contact the single fuel pin at a point longitudinally spaced from, with respect to the longitudinal axis of the fuel pin, and circumferentially offset from, the points of contact of the other two support members with the fuel pin, the points of contact of the three support members with the fuel pin being at the corners of a triangle such that the three points of contact will be spaced circumferentially around on the surface of the fuel pin.
Claim 2
Dependent Claim
196 words
A spacer grid for a nuclear reactor fuel assembly including a plurality of elongate fuel pins supported in a bundle with their longitudinal axes parallel, said spacer grid being of cellular form having openings through which the fuel pins will extend, no more than three substantially rigid support members extending into each of said openings and circumferentially spaced about said opening, resilient means being provided in each opening so as to be on a side of a single fuel pin in opposed relationship with said three support members and located to contact and bias said single fuel pin in the opening against the three support members, said support members being positioned so that a single port member will contact the single fuel pin at a point longitudinally spaced from, with respect to the longitudinal axis of the fuel pin, and circumferentially offset from, the points of contact of the other two support members with the fuel pin, the points of contact of the three support members with the fuel pin being at the corners of a triangle such that the three points of contact will be spaced circumferentially around on the surface of the fuel pin.
Claim 3
Dependent Claim
83 words
A spacer grid as claimed in claim 1 wherein said resilient means is adapted to contact the fuel pin at a point on the fuel pin intermediate between the point of contact of the one support member and the points of contact of the other two support members with the fuel pin, the resilient means being located to act on the fuel pin in opposition to the support members to bias the fuel pin into contact with all three of the support members.
Claim 4
Dependent Claim
158 words
A spacer grid as claimed in claim 1 comprising two superimposed layers of tubular ferrules, the ferrules in each layer being cojoined and the two layers of ferrules being supported in longitudinally spaced relationship in the spacer grid, whereby the fuel pins in a fuel assembly each will pass through a corresPonding pair of ferrules, one in each layer, two circumferentially spaced rigid support members being formed extending inside one ferrule of each pair of ferrules, a single rigid support member being formed extending inside the second ferrule of the pair of ferrules, so that the two rigid support members in the one ferrule and the single rigid support member in the second ferrule of each pair of ferrules are positioned at the corners of a triangle, spring means being provided in association with each pair of ferrules acting in opposition to the rigid support members and adapted to bias the fuel pins against the rigid support members.
Claim 5
Dependent Claim
47 words
A spacer grid as claimed in claim 3 wherein the spring means is arranged to act on the fuel pins at a point longitudinally between the two support members in the one ferrule and the single support member in the second ferrule of each pair of ferrules.
Claim 6
Dependent Claim
49 words
A spacer grid as claimed in claim 3 wherein the spring means comprises a bow spring mounted longitudinally between the two ferrules of each pair of ferrules, whereby the bow springs are adapted to bear on the fuel pins intermediate between the two ferrules of each pair of ferrules.
Claim 7
Dependent Claim
100 words
A spacer grid as claimed in claim 3 wherein a stop member is formed extending inside the one ferrule of each pair of ferrules on the opposite side of the ferrule to the two rigid support members therein and two circumferentially spaced stop members are formed extending inside the second ferrule of each pair of ferrules on the opposite side of the second ferrule to the single rigid support member therein, such that the fuel pins will be spaced from the stop members in the ferrules when the fuel pins are in contact with the support members in the ferrules.
Claim 8
Dependent Claim
188 words
A spacer grid as claimed in claim 1 having two superimposed grid structures, each grid structure comprising a plurality of strip members intersecting at right angles to define rectangular openings in the grid structures, such that the fuel pins of a fuel assembly each will extend through a corresponding pair of openings in the two grid structures, each pair of openings having spring means acting from one side thereof so as to bias a fuel pin extending through the openings towards the other side of the openings, and in each pair of openings two rigid support members extending into the opening in one of the grid structures, one from each side of the opening adjacent the spring means, a single rigid support member extending into the opening in the other of the grid structures from the opposite side of the opening to the spring means, the two rigid support members and the single rigid support member being adapted to contact the corresponding fuel pin at points on the corners of a triangle, the spring means being adapted to hold the fuel pin biassed against said rigid support members.
Claim 9
Dependent Claim
55 words
A spacer grid as claimed in claim 7 wherein the spring means is arranged to act on the fuel pins at a point longitudinally between the two rigid support members in the one opening and the single rigid support member in the other opening in each corresponding pair of openings in the two grid structures.
Claim 10
Dependent Claim
48 words
A spacer grid as claimed in claim 7 wherein the spring means comprises a bow spring mounted longitudinally between each corresponding pair of openings in the two grid structures such that the bow springs will bear on fuel pins at a point intermediate between the two grid structures.
Claim 11
Dependent Claim
170 words
A spacer grid as claimed in claim 7 wherein stop members are provided in the corresponding pairs of openings in the two grid structures to limit lateral movement of fuel pins passing therethrough away from contact with the rigid support members against the action of the spring means, a single stop member being provided extending into the opening of each pair of openings which has the two rigid support members, this single stop member extending into the opening from the side of the opening having the spring means, two stop members being provided extending into the other opening of the pAir of openings which has the single rigid support member, the two stop members extending into the opening one from each side of the opening adjacent to the side of the opening having the spring means, the stop members being located so as to be spaced from the fuel pins with the fuel pins held in contact with the support members in the pairs of openings by the spring means.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-11-12 | 1977-05-14 | 1977-11-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-12 | 1981-05-14 | 1981-11-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-12 | 1985-05-14 | 1985-11-13 | $7700.00 | Window Closed / Lapsed |