Light radiation is a crucial component of the energy produced in nuclear explosion, making the study of its space distribution highly significant. This paper presents the derivation of a formula for computing thermal energy induced by the light radiation of a nuclear explosion. The derivation integrates the fireball development laws with the transient energy dynamics of light radiation. The resultant formula exhibits a dependency on several factors, including the height of the explosion, the yield of the explosion, atmospheric attenuation coefficients, as well as the radius and temperature of the fireball. By creating diverse maps and adjusting pertinent parameters, simulating calculations are conducted to elucidate the distribution patterns of the transient thermal energy from nuclear explosion light radiation. Furthermore, the burn injury grading standards are incorporated into the simulation by introducing a search function that autonomously categorizes the injury grading zones on the virtual map. What’s more, neural networks are employed to train the numerical models, aiming to discern the correlation between the parameters associated with nuclear explosions and the injury grading radius on the map. This innovative approach enables direct prediction of the injury grading radius based on nuclear explosion parameters, thus significantly shortens the calculation process.