Estimate of the chimney maximum temperature and flow rate during the Pile 1 fire, Windscale, October 1957

Abstract

The temperature and flow rate are estimated of chimney gases emitted from the accidental fire in the Pile 1 nuclear reactor at the Windscale Works in October 1957. These are used in the study of the atmospheric dispersion of the chimney plume and of the radionuclides in it. The accident was one of great physical complexity, compounded by the fact that the number of installed sensors was, by modern standards, rather limited. Sophisticated computer modelling (CFD) is now available. However, the scope for validation in a one-off accident is limited. The mathematical simulation of the accident presented here is based on physically acceptable assumptions, chosen to represent a realistic worst case. These give a chimney gas temperature of 577 °C and a corresponding flow rate of 416 kg s-1. The uncertainties in these quantities are assessed in a sensitivity study