Part 1 of this two-part report presented a comparison of the irradiation-induced contraction rates obtained on standard-size graphite samples and the apparent moderator contraction rates of H, DR and C Reactors. The distortion trends of the top center of the graphite stacks, from which the apparent moderator contraction rates were derived, were presented as a function of cumulative power generation since start-up for each of the six older Hanford reactors. Since KE and KW Reactors are of identical construction, different in many details from the six older reactors, and have been operated under similar conditions, the data from KE and KW are treated as if from one reactor. As in Part 1, contraction rates apply to measurements made transverse to the extrusion axis of the bars. As used in this report, the depression rates refer to the rate of reduction in height of the top center of the reactor moderators. This depression rate is the net effect of contraction and expansion of the graphite bars. The depression rate is used to calculate the contraction rate of the individual bars. The contraction rates derived from the reactor data are compared with contraction rates of small samples of the same graphite (TSGBF) …

A study is in progress in which reactor operations will be simulated on the computer, the primary purpose being to evaluate the costs associated with various administrative alternatives which may be followed in conducting the overall operation, in addition to defining how operational costs are affected by such things as changes in fuel quality. The problem is complicated by the fact that the operation of the reactors is largely affected by random occurrences; no one can predict exactly when a tube will leak, or when a rupture will occur. Therefore, basic to the study is a probabilistic function, or set of functions, which govern the random aspects of reactor outages, and which can be used in the simulation study to generate reactor outages. This report is concerned with the derivation of such probabilistic functions. Although derived specifically for the simulation study, they are deemed of sufficient interest to warrant a separate report. Similar documents will be issued from time to time as the study progresses, and as results are found which are considered worthy of reporting prior to completion of the study.

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The methods used to fabricate the present loading of PuO{sub 2}-UO{sub 2} fuel elements for the Plutonium Recycle Test Reactor have resulted in alternating bands of high and low PuO{sub 2} concentration along each rod of the 19-rod elements. These bands are repeated every 1/2 or 1 inch along the length of the rod, depending on whether the loading of the oxides was done in 160 or 80 increments. This non-uniform distribution of PuO{sub 2} results in alternate regions of high and low heat generation rates with a direct influence on surface heat flux and fuel temperatures. Calculations were performed to determine the local surface heat fluxes and fuel temperatures in a rod of a PRTR 19-rod cluster PuO{sub 2}-UO{sub 2} fuel element. The results indicated that peak to average flux ratios of 2.37 could occur for fuel rods loaded in 80 increments (1 inch total band length) if no mixing of the PuO{sub 2}-bearing powder occurs with the UO{sub 2} powder. This would result in maximum heat flux of 660,000 Btu/hr-sq ft for a fuel element operating at a tube power of 1,200 KW. For a rod loaded in 160 increments (1/2 inch total band length), the peak heat …