Control rod drive for reactor shutdown
AssigneeThe United States of America as represented by the United States Energy Research and Development Administration
InventorsErnest R. McKeehan, Bruce M. Shawver, Donald J. Schiro, William E. Taft
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Abstract
A means for rapidly shutting down or scramming a nuclear reactor, such as a liquid metal-cooled fast breeder reactor, and serves as a backup to the primary shutdown system. The control rod drive consists basically of an in-core assembly, a drive shaft and seal assembly, and a control drive mechanism. The control rod is driven into the core region of the reactor by gravity and hydraulic pressure forces supplied by the reactor coolant, thus assuring that common mode failures will not interfere with or prohibit scramming the reactor when necessary.
Claims5
In combination, a control rod drive for scramming a nuclear reactor comprising:
- a control rod assembly;
- a latch mechanism for retaining and releasing said control rod assembly;
- a drive shaft assembly operatively connected to said latch mechanism;
- and a control drive assembly operatively connected to said drive shaft assembly, said control rod assembly and said latch mechanism being positioned within an outer casing extending through a reactor core;
- said drive shaft assembly extending through a reactor closure;
- and said control drive assembly being located on a side of said reactor closure opposite said outer casing;
- said control rod assembly being composed of a control rod region, a piston connected at one end of said control rod region and having a cross-section larger than an adjacent cross-section of said control rod region, a damper mechanism connected to said control rod region at an end opposite said piston, and a coupling head connected to said damper mechanism, said coupling head being releasably retained in said latch mechanism;
- said control rod assembly being movably positioned within a guide tube mounted within said outer casing and defining a high pressure fluid annulus therebetween, wherein fluid passes from the high pressure plenum through apertures in the core support structure and flows upwardly along said annulus, said fluid being vented through apertures in said guide tube located adjacent the control rod region and into the upper portion of said control rod region, said fluid passing therethrough for cooling said control rod assembly during normal operating conditions and for producing hydraulic pressures on the upper surface of said piston of said control assembly for driving said control rod assembly into the reactor core upon release of said control assembly by said latching mechanism, and said fluid thereafter passing through openings in said piston into the lower end of the control rod region and being vented to the low pressure plenum.
Dependencies are inferred from the claim text.