Techno Press
Techno Press

Structural Engineering and Mechanics
  Volume 97, Number 3, February10 2026 , pages 393-416
DOI: https://doi.org/10.12989/sem.2026.97.3.393
 


TNT equivalency of MegaMEX and CONWEP-based modeling of fully vented internal explosions in nuclear facilities
Seunggyu Lee, Sungbo Lee, Phill-Seung Lee

 
Abstract
    This study estimates the TNT equivalency of the commercial high explosive MegaMEX and evaluates the applicability of CONWEP-based blast modeling for fully vented internal explosions in nuclear facilities. Empirical blast-load models rely on TNT equivalency. However, uncertainties arise when non-TNT commercial explosives are involved and when explosions occur in internal environments. To address these issues, the TNT equivalency of MegaMEX was estimated using heat-based and detonation velocity-based scaling methods. Numerical simulations were performed using LS-DYNA with the CONWEP-based LBE card and validated against experimental measurements of peak overpressure and positive-phase impulse from a fully vented internal explosion test. Although originally developed for free-field detonations, the LBE card demonstrated reasonable accuracy under fully vented internal blast conditions. Among the scaling methods, the detonation velocity-based approach showed the closest agreement with experimental data. These results indicate that detonation velocity-based scaling provides a practical characterization of MegaMEX and that the LBE card offers a computationally efficient approach for internal explosion analysis in nuclear facilities.
 
Key Words
    CONWEP; internal explosion; LBE; LS-DYNA; MegaMEX; TNT equivalency
 
Address
Seunggyu Lee: Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
Sungbo Lee: Gen-IV Reactor Technology Development Division, Korea Atomic Energy Research Institute, 989 Daedeok-daero, Yuseong-gu, Daejeon 42057, Republic of Korea
Phill-Seung Lee: Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
 

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