HEAT TRANSFER FROM SPENT REACTOR FUELS DURING SHIPPING: A PROPOSED METHOD FOR PREDICTING TEMPERATURE DISTRIBUTION IN FUEL BUNDLES AND COMPARISON WITH EXPERIMENTAL DATA
A simple method has been developed for calculating or predicting temperature distributions in spent reactor fuels in shipping casks. The method acco\ints for radiant heat transfer between all the individual pins in a square array. With the dimensions of the fuel bundle, the configuration factors for radiation between various tubes in the bundle can be obtained from tabulated ntmiericaJ-calculations presented in this report. The configuration factors, along with the heat generation rates,
... ation rates, surface emissivity, ajid the temperature of the wall of the cask can be used to estimate the temperatiire distribution automatically with a computer code presented in this report or possibly by hand calculations by the method outlined. Experimental measiirements of temperature distribution in electrically heated tube arrays in steel shells that simulated shipping casks were made to test the proposed calculational procedure. Several heat generation rates and bundles containing up to 6h tubes were tested in 12-in.-and 6-ln.-inner diameter shells. Tests were made with the casks in horizontal and vertical positions. The predicted temperatiires were very near those observed experimentally under the conditions in which heat transfer is likely to be a problem in fuel shipment, that is, when the temperatures are near or above 200"C and the casks do not contain large empty spaces. These are the conditions where radiation should be expected to be the most important mechanism. The calculational method may also be adapted to nonsquare arrays.