PLENTIFUL ENERGY

CHAPTER 14
IFR DESIGN OPTIONS,
OPTIMUM DEPLOYMENT AND
THE NEXT STEP FORWARD
The IFR technology allows great flexibility in design of its nuclear
characteristics to configure its actinide fuel to breed excess fuel, to self sustain, or
to burn the actinides down. Perfectly practical deployments can answer almost any
future electrical energy need. The design of the IFR core can emphasize one or
another important characteristic, to a degree at will. In particular, the important
characteristics of breeding performance and the amount of fissile inventory can be
selected by the designer to give any breeding performance desired, over a wide
range. Before getting in to design considerations, we begin by describing the
appearance of an IFR plant. Then because choices for the coolant other than
sodium have been brought forward recently we review alternative coolants, helium
gas or lead and lead-bismuth alloys, and compare their characteristics to sodium‟s,
concluding that sodium remains much the best choice. We then go on to look at the
physics principles underlying breeding, showing the possible breeding
characteristics of the world‟s principal reactor types. Concentrating then on IFR
design itself, we show that fuel pin diameter is the important variable in
determining breeding in the core, and with this in mind, the way the thermal,
hydraulic, and mechanical constraints must be accommodated. Finally, we go on to
discuss tradeoffs that enter in further balancing the requirements for an optimum
design.
We then turn to the experience with fast reactor development in the past,
examine the various problems and difficulties that arose, and contrast that
experience with the thirty years of faultless operation of EBR-II. For all these
years, EBR-II has acted as a pilot demonstration of today‟s IFR technology, and in
the ease of its operation and its flexibility, as shown by the multitude of experiments
carried out on it, lies proof that IFR technology will provide a very high level of
reliability, maintainability, operability, and longevity.
Coming to the important subject of the effect of IFR deployment—the reason for
its development in fact—we show the importance of IFR deployment on world
uranium needs, based on the World Nuclear Association‟s estimates of nuclear
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