Fission product transport analysis: Task 2. Quarterly progress report, April--June 1977. [PWR; BWR; primary system reflooding following LOCA]

Continuing activities associated with modeling the transport and deposition of fission products within PWR and BWR primary systems during the reflood time period following a terminated LOCA are reported. The original scope of the overall project has been expanded to include consideration of conditions consistent with those leading to postulated core meltdown situations. Initial tasks on this continuation study involve limited improvements to the TRAP codes and performance of sensitivity analyses for terminated LOCA's plus the evaluation of thermal-hydraulic conditions for use in evaluating fission product transport and deposition in postulated meltdown situations. Beyond these initial tasks, emphasis will be concentrated solely on meltdown analyses. Major efforts within the past quarter have included completion in final form of the informal interim report on analyses for terminated LOCA conditions, initiation of improvement for the TRAP codes to include additional fission product deposition mechanisms, consideration of suitable methods for performing the sensitivity analyses, specification of ranges for variables to be covered in the sensitivity analyses, and initiation of efforts to specify flow conditions to be assumed in future development of analysis procedures applicable to meltdown conditions.