핵종 재고량 평가 프로그램 (RADMAN) 연계 중저준위 방사성폐기물 복합처분시설 폐쇄후 안전성 평가체계 개발

Abstract

Until now, for the purpose of setting-up criteria on radionuclide inventory and radioactivityconcentration for the disposal facility of LILW (Low- and Intermediate-Level radioactive Waste), thepost-closure safety assessment was iteratively conducted by trial-and-error approach using inputfile for radiation source term manually generating based on MS-excel files. Accordingly, not only wasreliability of assessment results insufficient due to frequent errors, but it was not possible to respondquickly to changes in external circumstances. In this study, to resolve this problem, we establishedthe safety assessment framework linking with nuclide inventory estimation and waste emplacementscheme through improving RADMAN (RADionuclide inventory MANagement program). As part of this,the necessary functions were assigned to ‘Emplacement scheme’ window in RADMAN to automate oreasily perform some processes required for setting up both the number of packages to be disposedof in each disposal unit and the source term model by package type. MS-excel file generated by usingthe corresponding function can be directly applied as input file for the GoldSim-based post-closuresafety assessment tool, which contains the radionulide inventory data by disposal unit and deteriorationtype of package. Through performing a case study for normal scenario of the first stage rock-caverndisposal facility on the basis of a specific emplacement scheme, it was confirmed that a series of linkageprocesses shown in Fig. 1 were properly implemented in this study. The assessment framework linkingwith RADMAN proposed in this paper can be applied to both individual and complex disposal facilityfor LILW, and it is expected to be utilized for more diverse purposes provided that it is improved and/orupgraded by reflecting the requirements of the end-user, Korea Radioactive Waste Agency (KORAD), inthe future.