The horizontal control rods presently installed in the older Hanford Reactors have inadequate heat transfer characteristics for present and predicted future operation of the reactors. Continued graphite stack distortion, coupled with higher graphite temperatures, has resulted in ECR failure during reactor operation, such as swelling of the outer aluminum sheaths to the extent that rod movement in the graphite channel is severely restricted. Continued graphite stack distortion will tend to further aggravate the problem of rod operation. A new HCR design concept,was developed by P. H. Hutton of Reactor Design, IPD, to alleviate some of the pressing operational problems. Prior to the acceptance of such a design, the important rod operating parameters should be known to some degree of accuracy. This study was conducted to detexmine, by calculational methods, the temperature distributions that could be expected to occur in such an HCR when used at the present operating power levels and at 120% of the present power levels.

None