Modifications for the Development of the MAAP-DOE (Modular Accident Analysis Program - Department of Energy) Code: Volume 8. Resolution of the Outstanding Nuclear Fission Product Aerosol Transport and Deposition Issues WBS 3.4.2.

摘要

A goal of the Department of Energy's Advanced Reactor Severe Accident Program (DOE ARSAP) is to develop an understanding of the risk associated with severe accidents (core melt) in advanced light water reactors (ALWRs). The behavior of fission products as they are transported as aerosols in the reactor's primary system and containment is part of this risk assessment. This report describes the modeling of nuclear aerosols for use in reactor safety analyses. Several outstanding issues concerning the modeling of aerosol behavior have been identified by the Nuclear Regulatory Commission (NRC) in response to the aerosol modeling performed during the Industry Degraded Core Rulemaking Program. In particular, this study addresses the issue of the applicability of the deposition correlation for the rapid release of aerosols. The NRC has taken the position that the correlations are marginally adequate for short-term releases and can only be appropriately used given sufficient time for the aerosol to approach the correlation curves. To address this issue, ARSAP has developed a sectional version of the Modular Accident Analysis Program code against which the correlation version of the same code is compared. The results indicate that the sectional method predicts about 15% more deposition than does the correlation technique. However, ARSAP has judged that this difference is not significant compared to the uncertainty of the available aerosol data for model verification and the modeling of other phenomena during the accident. Thus, ARSAP has concluded that the correlation method is a reasonable and adequate technique for such analyses. (ERA citation 14:026549)