This note documents the calculation of stresses resulting from temperature differences between the CC cryostat shell and the module array support beams, and the calculation of corresponding maximum allowable temperature differences to be monitored during the cooldown of the cryostat. A finite element model of a portion of the inner vessel shell was analyzed for a uniform temperature change. The shell was assumed to be completely restrained by the support beams. A maximum allowable temperature difference was determined based on limits on secondary stress ranges prescribed by the ASME Code (Section VID, Division 2). The maximum allowable difference between the cryostat shell and the support beams was found to vary from about 18K near room temperature to about 30K as the shell temperature approaches liquid argon temperature. The allowable values are tabulated below and plotted in Figure 1. The variation results from the decrease in the coefficient of thermal expansion of stainless steels at lower temperatures. As shown in the plot, the variation is roughly linear. Note that although the shell is assumed to be at the lower temperature in Fig. 1, the limitation on temperature difference will also apply during warmup, when the shell will likely be warmer than …

Deposition velocity is a parameter used in atmospheric transport models to specify the amount an atmospheric constituent transferred from the atmosphere to the surface of the earth. The material may deposit on the surface of soil, water, or vegetation. The deposition may be the result of rainfall or diffusion. A method for the calculation of deposition velocity based upon the decrease in deposition with distance from a point source is presented. The method does not require a knowledge of the time over which the deposition occurs or the concentration of the material in the atmosphere. However, the method does assume the deposition rate is proportional to the air concentration. The sensitivity to errors resulting from certain errors in the measurements and from violation of some of the assumptions of the model underlining the calculations are also to be discussed. The method has been used to estimate the deposition velocity of I-129. Two sets of I-129 deposition data at various distances from the center of SRS were used in the calculations. The results indicate that the deposition velocity is near a value of 0.2 cm/s. This is consistent with the processes that are known to control iodine deposition.

Deposition velocity is a parameter used in atmospheric transport models to specify the amount an atmospheric constituent transferred from the atmosphere to the surface of the earth. The material may deposit on the surface of soil, water, or vegetation. The deposition may be the result of rainfall or diffusion. A method for the calculation of deposition velocity based upon the decrease in deposition with distance from a point source is presented. The method does not require a knowledge of the time over which the deposition occurs or the concentration of the material in the atmosphere. However, the method does assume the deposition rate is proportional to the air concentration. The sensitivity to errors resulting from certain errors in the measurements and from violation of some of the assumptions of the model underlining the calculations are also to be discussed. The method has been used to estimate the deposition velocity of I-129. Two sets of I-129 deposition data at various distances from the center of SRS were used in the calculations. The results indicate that the deposition velocity is near a value of 0.2 cm/s. This is consistent with the processes that are known to control iodine deposition.