[en] Irradiated graphite arising from the decommissioning of KRR-2 (Korean Research Reactor 2) have shown to include somewhat degree of Wigner energy, specific radioactivity and the resulting radioactive chemicals/nuclides in the study of bulk mode of graphite structure. Plans of annealing and disposal of the irradiated graphite stored Wigner energy in its internal matrix of rearranged carbon structures due to neutron dose might depend on whether the storage stability of the graphite is attainable or not. That is, because the Wigner energy as a latent explosive energy in the graphite structure was caused by carbon atomic rearrangements or dimensional distortions in the graphite crystal lattice is very labile at higher temperature conditions than that of its formation, why it is of importance to forecast the thermal stability of the graphite in a long term storage. Moreover, since the nuclide emissions are directly related to the thermal stability of the graphite at the same time in view point of graphite disposal, the control of Wigner energy content in a lower level or naught in the waste program of the irradiated graphite might be necessary in the near future. A study on fire accident model as an emergency case analysis at a sudden external fire exposure of the irradiated graphite was proposed to assess the feasibility of the disposal storage of the graphite without any physical and/or chemical treatment of Wigner energy in the form of box disposal. In this study a fire accident model of the irradiated graphite, that is to be disposed in the radioactive waste storage facility in the forthcoming time, was considered to estimate the thermal stability of graphite, whether the Wigner energy of the irradiated graphite has an effect on the storage stability or not, in front of a sudden fire accident