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Current and future nuclear power reactors and plants 159

In the long term, a large system of 1200MW el may be envisaged. The LFR system
may be deployable by 2025.
Lead and LBE are relatively inert liquids with very good thermodynamic proper-
ties. The LFR would have multiple applications including production of electricity,
hydrogen, and process heat. System concepts represented in plans of the GIF System
Research Plan (SRP) are based on the European lead-cooled fast reactor (ELFR),
Russia’s BREST-OD-300 (fast reactor with lead coolant—Быстрый Реактор со
Свинцовым Теплоносителем in Russian abbreviations), and the small secure
transportable autonomous reactor (SSTAR) concept designed in the United States.
The LFR has excellent materials management capabilities, since it operates in the
fast-neutron spectrum and uses a closed fuel cycle for efficient conversion of fertile
uranium. It can also be used as a burner to consume actinides from spent LWR fuel and
as a burner/breeder with thorium matrices. An important feature of the LFR is the
enhanced safety that results from the choice of molten lead as a relatively inert and
low-pressure coolant. In terms of sustainability, lead is abundant and, hence, avail-
able, even in case of deployment of a large number of reactors. More importantly,
as with other fast systems, fuel sustainability is greatly enhanced by the conversion
capabilities of the LFR fuel cycle, because they incorporate a liquid coolant with a
very high margin to boiling and benign interaction with air or water. LFR concepts
offer substantial potential in terms of safety, design simplification, proliferation resis-
tance, and the resulting economic performance. An important factor is the potential for
benign end state to severe accidents.
The LFR has development needs in the areas of fuels, materials performance, and
corrosion control. During the next 5years, progress is expected on materials, system
design, and operating parameters. Significant test and demonstration activities are
underway and planned during this time frame.

4.3.5.5 Molten-salt reactor

The MSR (see Fig. 4.34) embodies the very special feature of a liquid fuel. MSR con-
cepts, which may be used as efficient burners of transuranic elements from spent LWR
fuel, also have a breeding capability in any kind of neutron spectrum ranging from
thermal (with a thorium fuel cycle) to fast (with a uranium-plutonium fuel cycle).
Whether configured for burning or breeding, MSRs have considerable promise for
the minimization of radiotoxic nuclear waste.
The MSR is distinguished by its core in which the fuel is dissolved in molten fluo-
ride salt. The technology was first studied >50years ago. Modern interest is on fast-
reactor concepts as a long-term alternative to solid-fuelled fast-neutrons reactors. The
onsite fuel-reprocessing unit using pyrochemistry allows breeding plutonium or
uranium-233 from thorium. R&D progresses toward resolving feasibility issues and
assessing safety and performance of the design concepts. Key feasibility issues focus
on a dedicated safety approach and the development of salt redox potential measure-
ment and control tools in order to limit corrosion rate of structural materials. Further
work on the batchwise online salt processing is required. Much work is needed on
molten-salt technology and related equipment.