Fast breeder reactor heat transport systems

The fest flux test facility (FFTF) was a 400 MW(th) sodium cooled last reactor specifically designed for development and testing of fast breeder reactor fuels, materials, and components. The reactor was a loop-type plant with three parallel heat transport system loops. The plant has neither steam generators nor blanket assemblies for fissile breeding, consistent with its role as a test reactor. The FFTF was equipped with a great deal of instmmentation. Each core assembly was provided with instruments for measurement of sodium flow rates and sodium outlet temperature. Three instrument trees, one of which serves each of the three core sectors, provide outlet instrumentation for all fiiel assemblies, control and safety assemblies, and selected reflector assemblies. In addition, 8 of the 73 core positions were equipped for full in-core instrumentation. Two of these eight positions were available for closed-loop facilities. 

Capital cost of the MSR could be almost the same as that of the LWR. There are many pros and contras for choosing between these two reactors. The MSR has 3 circuits with an intermediate heat transport system similar to fast breeder reactors. On the other hand, the thermal efficiency is -30% higher than that in a pressurized water reactor, the core pressure is very low, and the safety system is simplified. 

Oda, T., et al.. Design and Constraction of Heat Transport Systems of the Prototype Fast Breeder Reactor Monju, Proc. of the Intemat. Conference on Fast Reactors and Related Fuel Cycles, Kyoto, Japan, 1991. 

Roy, P., and Licina, G.J., Carbon Activity Determinations in a Bimetallic Sodium Loop Mock-up of the Intermediate Heat Transport System of a Liquid Metal Fast Breeder Reactor. Proceedings of the Third International Conference on Liquid Metal Engineering and Technology in Energy Production, Oxford, USA, April 1984,3,207. 

The modular double pool fast breeder reactor (MDP), a sodium cooled fast reactor of 325 MW(e) per module output, has been designed to reduce the construction costs and improve the reliability by factory production of most the components, see Annex XXII, Specifically, the MDP is proposed for use within a 4-module plant of 1300 MW(e).The development of the MDP concept has been performed and funded by the CRIEPI. The double pool design is intended to reduce the distances in the intermediate heat transport system by installing steam generators and secondary pumps in the sodium filled annular space formed between the primary and secondary vessel. The preliminary conceptual design has been completed but, at the moment, there is no financial support for further R D. 

For practical deployment of fast breeder reactors (FBRs) it is necessary to reduce construction costs. The construction cost of an FBR is high in comparison with an LWR due to the use of sodium as the coolant and the adoption of intermediate heat transport system. Therefore, the reduction and limitation of the sodium handling area and the simplification of intermediate heat transport system are effective measures for cost reduction. The objective of the MDP study is to establish a modular reactor concept that can compete with an LWR on construction costs. 

Figure 15.15 Prototype fast breeder reactor (PFBR) heat transport systems. SGDHR, Secondary sodium decay heat removal IHX, intermediate heat exchanger.

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