US3853699A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Nuclear reactor having control-rod retaining means
Assignee: Westinghouse Electric Corp
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Filing: 1971-09-13
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Granted: 1974-12-10
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Expires: 1991-09-13
Abstract
Abstract A nuclear reactor has control rods which may be operated between control positions and retracted positions by linearly-movable elements or drive means. In the retracted position, a control rod or a group of control rods may be retained by latches, the lower tips of which enter a groove in a linearly-movable element or drive means. The latches are movable between a released position and a restraining position. The latches are made of magnetic steel and are maintained in the restraining position by permanent magnet means which are operable between a coupled magnetic position wherein the drive means is maintained in the restraining condition and a decoupled position wherein the latches may release the associated drive means. Such operation of the magnet is in response to movement of a missile shield associated with the nuclear reactor.
Inventors
- 👤 E Frisch
- 👤 H Andrews
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 16:02
CPC Classifications
G; G21; G21C; G21C19/00; G21C19/02; G21C19/12; G21C7/00; G21C7/06; G21C7/08; G21C7/12; Y; Y02; Y02E; Y02E30/00; Y02E30/30
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
293 words
In a nuclear reactor of the type designed for rapid refueling comprising: a closed pressure vessel, a plurality of upstanding elongated fuel assemblies containing nuclear fuel located in said vessel, at least some of said fuel assemblies including elongated openings extending longitudinally therethrough, a plurality of elongated movable neutron-absorbing control rod means positioned in said openings respectively for movement into and out of said some fuel assemblies, a plurality of control rod drive mechanisms supported on said vessel and each including drive means secured to each of said control rods, respectively, each of said mechanisms including operating means for individually and incrementally moving said associated drive means and associated control rod means to a plurality of holding positions between first and second extreme positions, said first extreme position being with said associated control rod means fully inserted in its associated fuel assembly, said second extreme position being with said associated control rod means being fully withdrawn from said associated fuel assembly, latching means in each of said mechanisms which mechanically engages the drive means only when said associated control rod means is in said second extreme position to hold said control rod means in said withdrawn position, actuating means mounted on each mechanism, one for each of said latching means for selecTively actuating each of said latching means into engagement with said associated drive means; and selectively operable movable means mounted on each of said mechanisms, said movable means being coupled with said actuating means to permit movement of said actuating means longitudinally of said mechanism and into a position to actuate said latching means into engagment with said drive means, thereby holding said drive means and attached control rod means in said withdrawn position during the time the reactor is being refueled.
Claim 2
Dependent Claim
293 words
In a nuclear reactor of the type designed for rapid refueling comprising: a closed pressure vessel, a plurality of upstanding elongated fuel assemblies containing nuclear fuel located in said vessel, at least some of said fuel assemblies including elongated openings extending longitudinally therethrough, a plurality of elongated movable neutron-absorbing control rod means positioned in said openings respectively for movement into and out of said some fuel assemblies, a plurality of control rod drive mechanisms supported on said vessel and each including drive means secured to each of said control rods, respectively, each of said mechanisms including operating means for individually and incrementally moving said associated drive means and associated control rod means to a plurality of holding positions between first and second extreme positions, said first extreme position being with said associated control rod means fully inserted in its associated fuel assembly, said second extreme position being with said associated control rod means being fully withdrawn from said associated fuel assembly, latching means in each of said mechanisms which mechanically engages the drive means only when said associated control rod means is in said second extreme position to hold said control rod means in said withdrawn position, actuating means mounted on each mechanism, one for each of said latching means for selecTively actuating each of said latching means into engagement with said associated drive means; and selectively operable movable means mounted on each of said mechanisms, said movable means being coupled with said actuating means to permit movement of said actuating means longitudinally of said mechanism and into a position to actuate said latching means into engagment with said drive means, thereby holding said drive means and attached control rod means in said withdrawn position during the time the reactor is being refueled.
Claim 3
Dependent Claim
184 words
A nuclear reactor as claimed in claim 1 wherein said vessel includes a base portion and a releasable closure head for the base portion, a tubular housing for each of said drive mechanisms, each of said tubular housings extending along a vertical axis in sealed relationship through the closure head, said operating means for each of said drive mechanisms including gripper means within the associated housing operable for releasably gripping the associated drive means to incrementally move the associated drive means in repeated steps in a vertical path, and said latching means comprises a pair of pivotally mounted levers in said housing above said gripper means, each of said drive means having grooves in its periphery to receive the body portion of said levers when the ends thereof engage the drive means, said actuating means including permanent magnets movably mounted on each housing, each of said tubular housings having magnetic parts forming a path of low magnetic reluctance between the permanent magnets and the magnetic levers when the magnets are moved to a position opposite the body portion of the levers in said grooves.
Claim 4
Dependent Claim
43 words
The nuclear reactor according to claim 1 wherein said actuating means comprises a magnetic device mounted on said mechanism opposite from the latching means, whereby the magnetic device acts to move the latching means by magnetic attraction into engagement with the drive means.
Claim 5
Dependent Claim
49 words
The nuclear reactor according to claim 1 wherein each of the latching means comprises at least one lever in the mechanism selectively movable by said actuating means into engagement with the drive means to hold the drive means and its connected control rod means in the second extreme position.
Claim 6
Dependent Claim
69 words
The nuclear reactor according to claim 4 wherein each actuating means comprises at least one permanent magnet movably mounted in a housing on said mechanism, and means associated with said permanent magnet for holding it in a lower position out of flux linking relationship with said lever and for moving it to an upper position wherein the lever is actuated by magnetic attraction into engagement with the drive means.
Claim 7
Dependent Claim
141 words
The nuclear reactor according to claim 1 wherein each latching means comprises a pair of levers movably mounted in said mechanism; spring means between said levers for biasing one end of each lever into engagement with the drive means; means on said end of each lever having a configuration complementary to a portion of the drive means for facilitating the holding of the drive means in the second extreme position; and wherein said actuating means comprises a pair of permanent magnets respectively mounted on each mechanism opposite from each lever and movable between a lower position where the levers lie outside the permanent magnet field and an upper position where the lever ends are moved by magnetic attraction into engagement with the drive means thereby precluding movement of the drive means and attached control rod means into their respective fuel assemblies.
Claim 8
Dependent Claim
27 words
The nuclear reactor according to claim 6 wherein displaceable means are coupled to said permanent magnets for selectively moving said magnets between said lower and upper positions.
Claim 9
Dependent Claim
62 words
The nuclear reactor according to claim 7 wherein said permanent magnets are movably mounted in housings on each mechanism; and spaced sections of magnetic material in the walls of said mechanism directly opposite from said levers and from the permanEnt magnets when located in the upper position thereby establishing a low reluctance path from the magnets through the magnetic material and levers.
Claim 10
Dependent Claim
109 words
The nuclear reactor according to claim 7 wherein said displaceable means comprises a displaceable missile shield surmounting said pressure vessel; a movable coupling device on each mechanism; an actuator rod interconnecting each of said permanent magnets with each coupling device; and spring means on each rod which urges each permanent magnet into said upper position, the arrangement being such that when the missile shield is displaced downwardly, each magnet is held in said lower position and when the missile shield is displaced upwardly, the spring means acts to move said magnets from the lower to the upper position and therefore into alignment with the magnetic material on its mechanism.
Claim 11
Dependent Claim
138 words
The nuclear reactor according to claim 1 wherein the drive means moves linearly in a bushing in each mechanism; and wherein said latching means comprises a pair of oppositely disposed levers pivoted on said bushing, each of said levers having an end engageable with a complementary surface on the drive means to hold the drive means in said mechanism, each of said levers further having a body portion extending from said ends in a direction upwardly in said bushing; shock absorbing means interconnecting said bushing with a stationary section of said mechanism; whereby after the actuating means moves the levers into engagement with the drive means, said shock absorbing means will contain any shock imposed on said bushing in the event the drive means and attached control rod means inadvertently drops in a direction toward the fuel assembly.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-12-09 | 1978-06-10 | 1978-12-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-09 | 1982-06-10 | 1982-12-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-09 | 1986-06-10 | 1986-12-10 | $7700.00 | Window Closed / Lapsed |