Liquid metal—cooled fast reactors safety

Liquid metal cooled fast reactors are classified as RIs which safety is ensured principally due to their inherent self-protection. It is associated with a number of their internal features. 

Passive safety systems and plant designs from liquid metal cooled fast reactors. 

INTERNATIONAL ATOMIC ENERGY AGENY, Status of Liquid Metal Cooled Fast Reactor Technology, IAEA-TECDOC-1083, Vienna (1999). Safety of Beloyarsk NPP operation, (Collection of scientific proceedings), Ekaterinburg UrO RAN, ISBN 5-7691-0469-4 (1994). 

Liquid metal-cooled fast reactor (LMFR) safety (Class L) Single-phase, high-enthalpy... 

Reactors with a fast neutron spectum allow to perform a quantum leap in the use of resources (factor of -100) and can further defuse the waste problem, as they allow the fuel cycle to be fully closed. They fulfil, therefore, an important postulate for a sustainable development. The quantum leap implies, however, a more expensive and complex technology (e.g. liquid metal cooling technology). By steadily exploiting advantages like the low coolant pressure, new developments (IFR, EA) could probably reach a safety standard that is at least equivalent, or even better than the standard of the best LWRs. 

NNC have also contributed to an investigation of radical alternatives to the EFR design by examining the potentiality of a gas-cooled fast reactor, based on past UK studies and on the extensive UK experience of AGR thermal reactors. There are advantages over liquid metal coolants in terms of in-service inspection and repair, but there may be difficulty in meeting safety requirements. 

Pure lead and the eutectic alloy of LBE (consisting of 44.5% lead and 55.5% bismuth) are the principal potential coolants for LFR systems. Table 6.1 shows some key properties of LBE and lead with sodium also included for reference and comparison. Further details on the properties of lead coolants can be found in OECD-NEA (2015). The shared property that both LBE and lead are essentially inert in terms of interaction with air or water is the noteworthy advantage that LFRs have in comparison with the other principal liquid metal-cooled reactor, the sodium-cooled fast reactor (SFR). This basic property has significant implications for design simplification, safety performance, and the associated economic performance of such systems in comparison with SFRs and other Generation IV systems. 

The present study analyzes a postulated break in the primary pump discharge pipe to assure the inherent safety of KALIMER. KALIMER is a pool-type liquid metal sodium cooled fast reactor plant. The main concern of the accident is the amount of subcooling margin reduction, i.e., the degree of increase in the fuel and the coolant temperatures. The stabilization of power associated with reactivity feedback is also an important aspect of the accident. The analysis is performed with the SSC-K code, which was developed on the basis of the SSC-L code for the... 

The technology base for the LFR is primarily derived from the Pb-Bi liquid alloy-cooled reactors employed by the Russian Alpha class submarines. Technologies developed from the integral fast reactor metal alloy fuel recycle and refabrication development, and from the advanced liquid metal reactor (ALMR) passive safety and modular design approach, may also be applicable to the LFR. The ferritic stainless steel and metal alloy fuel developed for sodium fast reactors may also be adaptable to the LFR for those concepts with reactor outlet temperatures in the range of BSO C. 

Supercritical pressure reactor concepts and nuclear superheaters were studied as reactor concepts by WH and GE in the 1950s and 1960s when LWR design and safety had not yet been established. New supercritical pressure reactor concepts emerged in the 1990s from Japan, Russia, and Canada as innovative water cooled reactors. Steam cooled FBRs were studied in the 1950s and 1960s as an alternative to liquid metal fast breeder reactors. These steam cooled FBRs require a... 

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