A review of pebble bed reactors and the characteristics of packed beds

Abstract

This paper gives a general picture of the pebble bed reactor concept up to the present time. The main advantages and disadvantages are listed, these being chiefly concerned with the rather unique spherical fuel element.

The principal performance and design data etc. are given for an experimental pebble bed reactor and power plant as conceived by the Oak Ridge design team. Also included are data and a description of the BBC-Krupp reactor (AVR) of the pebble bed type under construction at Julich in West Germany; mention is also made of a possible West German pebble bed power reactor (THTR). An account is given of the Australian work on pebble bed reactors which differs from all others in the choice of support material for the fuel.

A more detailed account follows of three important aspects of this reactor type—fuel elements, coolant contamination and fuel handling. This is followed by sections on the heat transfer and fluid dynamic characteristics of packed beds, of which the pebble bed reactor is an example.

In conclusion some of the principal research and development problems associated with this reactor concept are discussed.

An Appendix summarizes the various pebble bed reactors conceived since the original conceptual design by Farrington Daniels in 1944.