乏燃料桶外部剂量的MCNP分析

乏燃料运输容器是运输反应堆乏燃料的专用设备.文章使用MCNP4C软件计算西屋MC-10乏燃料桶的外部剂量率,方法是基于网格的定义,得到桶周围外部整体剂量率,并与前研究工作者Georgeta Radulescu的计算结果相比,结果一致性符合较好,使用网格造成机时耗费较大,也存在一定误差,但能够比较全面,详尽地得到关于乏燃料桶外部剂量的一些数据,可以对工作人员确定乏燃料桶外部剂量有一定的参考意义.     

The Application of Fluid Structure Interaction Techniques Within Finite Element Analyses Of Water-filled Transport Flasks

Abstract

Historically, finite-element (FE) analyses of water-filled transport flasks and their payloads have been carried out assuming a dry environment, mainly due to lack of robust fluid structure interaction (FSI) modelling techniques. Recent years have seen significant improvements in FSI techniques. These FSI techniques have been used to investigate the effects of assuming a wet environment for the regulatory drop test within a recent Rolls-Royce Naval Marine licence renewal application. This paper will present the FSI capabilities available within various FE codes. The required structural aspects of the FE codes will also be discussed, in particular material models, as these also influence the final code selection. Two explicit dynamic FE codes were finally identified, LS-DYNA, which was used in the extant dry analyses, and RADIOSS, which was used to provide additional confidence in the FSI calculations. Fluid flow and pressure vary significantly during an impact and the effects on the contents become complex when water is incorporated into the flask analyses. Therefore, a verification and validation (V&V) exercise was undertaken to underpin the FSI techniques eventually used. Modelling a fluid environment within the entire flask to capture the explicit effects of fluid on a complex structure is impractical. A good understanding of the FSI techniques and assumptions regarding the fluid boundaries is therefore required for a representative FSI model. A number of V&V problems are presented which test key features required for analysing the payload in a water environment. In conclusion the paper will discuss FSI technology, lessons learnt, limitations of FSI techniques and further possible applications.