THERMAL ANALYSIS OF DRY STORAGE AND TRANSPORTATION CASKS CASTOR USING COBRA-SFS

Martin Ševeček,Chih-Hao Lee,Mojmír Valach

doi:10.14311/app.2020.28.0032

Martin Ševeček, Chih-Hao Lee + Show 1 more

Open Access

https://doi.org/10.14311/app.2020.28.0032

Copy DOI

Abstract

State Office for Nuclear Safety is a regulator body in the Czech Republic handling also licensing of storage and transportation casks (SCs) of the spent nuclear fuel (SNF). One of the main concerns for the dry storage of SNF is the safe removal of the residual heat resulting from the decay of fission products, actinides, and activated construction materials. There are many storage systems in use around the world with different storage configuration, fuel designs and boundary conditions that need to be evaluated. Two thermal models of SNF storage casks CASTOR 440/84 and CASTOR 440/84M were developed using the COBRA-SFS code, which is an internationally accepted and validated code used for licensing of dry storage casks and safety evaluation. The casks are in operation at the Nuclear Power Plant Dukovany for dry storage of the WWER-440 SNF. Both models were validated and used for evaluation of several problems in different configuration and particularly for licensing purposes at the SUJB.

Highlights

The accurate prediction of heat transfer and temperature fields in a dry storage cask CASTOR has been undertaken
This paper focuses on the safe removal of heat from the spent nuclear fuel, the design of a storage and transportation casks (SCs) has to ensure all safety functions
The reference configurations were calculated using COBRA-SFS code and compared with the results provided by the applicant

Summary

Introduction

The accurate prediction of heat transfer and temperature fields in a dry storage cask CASTOR has been undertaken. Due to the nature of the dry storage casks, the temperature cannot be directly controlled and calculations are performed to ensure safe storage and transport of SNF in all postulated conditions during decades of dry SNF storage. Many applicants for a license of storage and transportation cask ( in the Czech Republic) have used Computational Fluid Dynamics (CFD) codes to simulate the thermal behavior of dry storage systems. The State Office for Nuclear Safety in the Czech Republic (SUJB) decided to perform confirmatory independent calculations of the thermal behavior of SC CASTOR using COBRA-SFS code [9] in cooperation with Department of Nuclear Reactors, CTU in Prague and UJV Rez as recommended by international standards [10, 11]. The subchannel code COBRA-SFS based on the well-known COBRA thermohydraulical code has been used for thermal analysis of different systems with PWR, BWR and WWER fuel geometries [12,13,14,15,16]

Methods

Results

Conclusion