XYLENE POWER LTD.

FNR DEPLOYMENT

By Charles Rhodes, P.Eng., Ph.D.

INTRODUCTION:
This web page reviews the circumstances in which deployment of Fast Neutron Reactors (FNRs) makes economic or technical sense.
 

IMPORTANCE OF FNRs:
FNRs provide the only non-CO2 emitting technology that can sustainably and economically fully displace fossil fuels. Unlike water cooled reactors, FNRs with low pressure coolants can be safely sited within major cities for supply of electricity, industrial/commercial heat and district heat. Such siting reduces electricity transmission costs and can reduce the cost of comfort heat about three fold as compared to supply of comfort heat using remotely located water cooled reactors.

FNRs operate by converting abundant fertile isotopes such as U-238 and Th-232, into fissile isotopes such as Pu-239 and U-233, faster than the fissile isotope inventory is consumed. In concert With nuclear fuel recycling, FNRs can reduce the consumption of natural uranium per kWhe output by more than 100 fold as compared to water cooled reactors. This issue will become of increasing importance as existing rich natural uranium deposits are depleted and as nuclear power displaces fossil fuels.

FNRS operate at higher temperatures than water cooled reactors. These higher temperatures increase the efficiency of thermal electricity genertion and enable use of dry cooling towers for rejection of waste heat. A FNR is more expensive than a lower cost water cooled reactor of the same power. Hence the present market for FNRs is concentrated in circumstances where the performance advantages of FNRs justify the extra cost.

For remote sites that have large electricity loads (over 1 GWe) and unlimited water cooling capacity, on a simple capital cost per kWe of electricty generation capacity, FNR technology is not price competitive with BWR (Boiling Water Reactor) and PWR (Pressurized Water Reactor) technology. The market for FNRs is in applications where large BWRs and large PWRs either cannot function or cannot economically compete. These markets include urban district energy systems, communities with populations less than 300,000, communities with little or no cooling water, industries that need process heat in the temperture range 300 degrees C to 500 degrees C and nations that lack natural nuclear fuel and hence value nuclear fuel sustainability.
 

FNR MARKETS:
In certain markets and in certain applications FNRs offer features that are not available from water cooled reactors.
1) One market is supply of both heat and electricty for urban district heating in regions where winter temperatures routinely fall below 0 degrees C. In these markets the reactors need to be sited within cities and to have no requirement for an external public safety exclusion zone a is required by most water cooled nuclear reactors;

FNR SAFETY ISSUES:
The public safety issues applicable to a FNR sited in a major city are significantly different from the public safety issues applicable to a remotely sited water cooled reactor surrounded by a public safety exclusion zone. The FNR specific safety issues are extensively addressed on this web site. The over riding issues are that the FNR elevation must be sufficient to ensure that the FNR will never be flooded by water and the FNR's foundation must rest on contiguous bedrock with a long term load bearing capacity in excess of 30 tonnes/ m^2.
 

FNR FIRST OF A KIND (FOAK) ISSUES:
A major practical issue with FNRs is training continuityof engineering personnel. At various times during the last 60 years FNRs have been deployed by the USA, Soviet Union, Russia, France and China. However, these deployments have been intermittent. That intermittency has led to repeated loss of trained engineering personnel. The consequence of that loss is that each new FNR deployment is in effect a First of a Kind (FOAK) project for the personnel involved, with all the attendant training costs. This training problem applies to both FNRs and FNR fuel production. The result is that until FNRs are deployed in a sustained sequence by a single party, FNR technology will remain expensive as compared to existing water cooled reactor technology.
 

SUMMARY:
In general FNRs are more complex and more expensive than water cooled reactors of similar thermal capacity. However, FNRs are essential to conserve the world supply of natural uranium, without which economic nuclear power is impossible.

At this time FNRs are only economic in markets where, for varius practical reasons, FNRs provide essential features that water cooled reactors cannot economically provide.
 

This web page last updated April 17, 2026.

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