CONTROL OF NUCLEAR REACTORS

• US 3,773,619 A
• Filed: 05/21/1970
• Issued: 11/20/1973
• Est. Priority Date: 05/30/1969
• Status: Expired due to Term

• Current Assignee: Edward Duncombe, Eustace Lionel Ernest Harrington
• Original Assignee: Edward Duncombe, Eustace Lionel Ernest Harrington
• Inventors: Duncombe, Edward, Harrington, Eustace Lionel Ernest
• Primary Examiner(s): Behrend, Harvey E.
• Application Number:
  US05/039,302
• Time in Patent Office: 1,279 Days
• Field of Search: 176/86G,86L,86M,22
• US Class Current: 376/330
• CPC Class Codes: G21C 7/22 by displacement of a fluid or fluent neutron-absorbing material , e.g. by adding neutron-absorbing material to the coolant
• CPC Class Codes: Y02E 30/30 Nuclear fission reactors

Abstract

A control device chargeable as a unit into the core structure of a nuclear reactor comprises a reservoir and a receiver for a neutron absorbing liquid metal such as lithium 6. With the device located in the core structure of the reactor the receiver is located in the fuel zone of the core structure with the reservoir located above the receiver. A feed line for the lithium metal links the reservoir with the receiver and a flow coupler energised by flow of liquid metal reactor coolant is provided to inhibit the transfer of lithium from the reservoir to the receiver when the flow coupler is fully energised. Reduction of the degree of energisation of the flow coupler due for example to a fall in the rate of flow of liquid metal reactor coolant through the flow coupler results in transfer of lithium from the reservoir into the receiver to shut down the reactor. The flow coupler is also adapted to return the lithium from the receiver to the reservoir through a return line when energised by return to full rate of flow of liquid metal reactor coolant through the flow coupler.

Claims

1. In combination with a liquid metal cooled nuclear reactor system a control capsule chargeable and dischargeable as a unit into and from said system, said capsule comprising, for a liquid metal neutron absorber to control said system, an upper reservoir and a lower receiver, a first pipe from the reservoir to the receiver of U-shape having a flow control element for controlling liquid metal neutron absorber flow from reservoir to receiver, a second pipe defining an inlet opening and an outlet opening for flow of liquid metal coolant of said reactor system through the capsule, and electromagnetic coupling means associating a predetermined coolant flow, on the one hand, and a predetermined reduction of said coolant flow, on the other hand, in said second pipe with said flow control element so that with said predetermined flow the flow control element acts to prevent flow of liquid metal neutron absorber from the reservoir to receiver and with predetermined reduction of flow the flow control element acts to permit flow of liquid metal absorber from the reservoir to the receiver, said coupling means comprising means for setting up a magnetic field passing transversely across a plurality of ducts one of said ducts having with said second pipe passing through it so that flow of liquid metal coolant through said second pipe generates an electromagnetic force by interaction with said magnetic field, and another of said ducts having with said flow control element containing liquid metal absorber passing through it, and arranged to accept in said absorber the generated electromagnetic force from the coolant to create, by interaction with said magnetic field, pressures in the liquid metal absorber of the control element to prevent or permit flow of liquid metal absorber through said first pipe from reservoir to receiver, and means for returning liquid metal neutron absorber in the receiver to the reservoir.

2. The combination of claim 1 wherein the means for returning absorber in the receiver to the reservoir comprises a third pipe passing through yet another of said plurality of ducts, and containing liquid metal absorber, and arranged to accept in that absorber the generated electromagnetic force from the coolant to create, by interaction with said magnetic field, pressures in that absorber to cause absorber to be pumped back from the receiver to the reservoir when a predetermined flow is reestablished in the flow of liquid metal coolant in said second pipe.

3. The combination of claim 2 wherein the U-shaped first pipe comprises gas lock forming means connected with that end of said first pipe which is open to the reservoir to prevent or permit flow of absorber from reservoir to receiver, and said flow control element is a pipe containing liquid metal absorber located in said gas lock forming means to release or sustain the lock according to pressures created in the pipe of the control element.

4. The combination of claim 1 having flow preventing means insertable in said second pipe and an electromagnet for holding said means in the non-inserted position from where it can fall by gravity to the inserted position on de-energising the electromagnet whereby said flow control element is actuated to permit flow from the reservoir to the receiver.