We present a Fortran 90/95 code for computing the G(E) function, which transforms a gamma-ray pulse height spectrum to the ambient dose equivalent [H*(10)] rate, to make the G(E) function more easily accessible to any interested party. Our program code uses as input data pulse height spectra at various energies for a specific gamma-ray detector and the values of H*(10) per unit fluence at the corresponding energies, both of which are obtained with the PHITS code.

In this study, numerical computations of condensation heat fluxes along a vertical flat plate from steam and air mixtures in a rectangular flow channel with a condensation height of 6 m were carried out using the computational fluid dynamics (CFD) code FLUENT to evaluate condensation heat fluxes q_c on the containment wall under accident conditions. The distributions of the computed heat flux q_x,CFD values along the flow direction x agreed relatively well with those of the q_x,exp values measured with the COPAIN facility with a condensation height of 2 m at a steam mass fraction of Y_s,in = 0.133–0.233, and the standard deviation of the q_x,CFD values to the q_x,exp values was s = 13%. The q_x,CFD values were numerically obtained with a mixture velocity range of u_in = 0.27–3.2 m/s at Y_s,in = 0.453, and they were compared with the q_c,NC values computed by existing correlations for natural convection (NC) condensation. A combination of a q_c correlation and a correlation for the Sherwood number Sh_x,NC in the q_c correlation was evaluated, the coefficient for Sh_x,NC was optimized, and the standard deviation of the q_x,NC values to the q_x,exp or q_x,CFD values was s = 16%.

Considering the submersion of equipment installed in a building with a watertight door, the failure probability of the equipment owing to tsunami inundation is affected by leakage through the watertight door. The leakage has the characteristic of surging at an uncertain threshold. This study is aimed at developing the methodology of fragility evaluation that takes into account the uncertainties of the threshold. The evaluation methods with three grades based on the level of detail in assessment were proposed. The parameters in fragility evaluation were evaluated from the results of previous leakage tests of watertight doors. Each method was validated by comparing the fragility curves based on the proposed method with those obtained by the Monte-Carlo method. As a result of a comparison between the fragility curves for three grades, two characteristics were revealed. The first was that the failure probabilities are higher for the lower grades than for the higher grades. The second was that the failure probability for the lowest grade surges at a specific point since the threshold is conservatively calculated. The level of detail required in the assessment should be considered to select the appropriate method.