DANIEL FULLER JONES
Medical Practice in Pittsburgh, PA

3957575, May 18, 1976

Apr 16, 1974

5/461475

William L. Fauth - Germantown MD
Daniel S. Jones - Pittsburgh PA
George J. Kolsun - Pittsburgh PA
John G. Erbes - San Jose CA
John J. Brennan - Bethel Park PA
James A. Weissburg - Pittsburgh PA
John E. Sharbaugh - Acme PA

The United States of America as represented by the United States Energy
Research and Development Administration - Washington DC

G21G 102, G21C 328, G21C 1900

176 18

In a light water reactor system using the thorium-232 -- uranium-233 fuel system in a seed-blanket modular core configuration having the modules arranged in a symmetrical array surrounded by a reflector blanket region, the seed regions are disposed for a longitudinal movement between the fixed or stationary blanket region which surrounds each seed region. Control of the reactor is obtained by moving the inner seed region thus changing the geometry of the reactor, and thereby changing the leakage of neutrons from the relatively small seed region into the blanket region. The mechanical design of the Light Water Breeder Reactor (LWBR) core includes means for axially positioning of movable fuel assemblies to achieve the neutron economy required of a breeder reactor, a structure necessary to adequately support the fuel modules without imposing penalties on the breeding capability, a structure necessary to support fuel rods in a closely packed array and a structure necessary to direct and control the flow of coolant to regions in the core in accordance with the heat transfer requirements.