Unique thermal and hydraulic features of the Light Water Breeder Reactor (LWBR development program)

Technical Report · Mon Jan 01 00:00:00 EST 1979

OSTI ID:6180330

McWilliams, K D; Turner, J R; Stout, J W; Lerner, S

The objective of the Light Water Breeder Reactor (LWBR) Program is to develop the technology necessary to significantly improve the fuel utilization of light water thermal reactors. This technology has evolved by developing, designing, and fabricating a reactor core that is operating in the DOE-owned reactor plant at Shippingport, PA. Reactor operation is expected to demonstrate that net breeding of U233 (approximately 1 percent more fissile fuel at end of life than in its initial loading) can be achieved in a light water reactor system using the thorium--uranium-233 fuel system in a seed-blanket core configuration. The design for the LWBR core was developed within the constraints of the Shippingport Plant. This design provides a simulation of a large core environment in the interior of the demonstration core, and permits net breeding in the entire core. In the design hexagonal modules are arranged in a symmetric array surrounded by a reflector blanket region. There are four basic regions: the seed, the standard blanket, the power flattened blanket, and the reflector. The center three sed/blanket moduel design is such that the more highly loaded seed has a k I greater than one and te lower loaded blanket has a kinfinity less than one. Reactivity is controlled by varying the leakage of neutrons from the small seed regions into the blanket regions. This is achieved by axially positioning the seed section of the core so as th change core geometry rather than by using conventional parasitic neutron-absorbing poisons. With this method of control, which is one of the major advantages of the seed-blanket concept, excess neutrons are absorbed in fertile thorium material, and good neutron economy is achieved. To improve the reactivity worth of the movable seed assembly a stepped fuel design was utilized. In addition, to further enhance breeding the module water volume was minimized by placing rods close together on a triangular pitch.

• Research Organization: Bettis Atomic Power Lab., West Mifflin, PA (USA)
• DOE Contract Number: EY-76-C-11-0014
• OSTI ID: 6180330
• Report Number(s): WAPD-T-2729; TRN: 79-010418
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
SHIPPINGPORT REACTOR
REACTOR CORES
BREEDING BLANKETS
CRITICAL HEAT FLUX
DESIGN
HEAT TRANSFER
HYDRAULICS
LWBR TYPE REACTORS
BREEDER REACTORS
ENERGY TRANSFER
ENRICHED URANIUM REACTORS
FLUID MECHANICS
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WATER COOLED REACTORS
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Breeding