A5-1 Analysis of the core without refrigeration

The simple spreadsheet macro dryco.xls (available on the companion website) calculates the distribution of temperatures in a core (in downloadable file DRYCORE) without any refrigeration except for the radiation heat transfer towards the vessel and towards the surrounding concrete cavity. The calculation is a simplified one and is based on that used for the Rasmussen Report (Rasmussen, 1978). 

As explained at the beginning of Appendix 2, some of the units are not in the S.I. System, for historical reasons. 

The input data are the temperature at the centre of the core, the total decay heat, and the dimensions of the core, the vessel and the external cavity. 

It is assumed that heat transfer occurs only in the radial direction. In reality, 10-12 per cent of the heat is dissipated axially (Rasmussen, 1978). The core power peaking factor (radial) is assumed to be 1.5, with a linear distribution as a function of the radius. 

In normal operation, however, an axial peaking factor of 1.4—1.5 should also be taken into account. 

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