Liquid lead—bismuth eutectic

Jun Lim HLMC-2008 Corrosion behaviors of commercial FeCrAl alloys in liquid lead—bismuth eutectic environments... 

Jun Lim Journal of Nuclear Materials A Study of early corrosion behaviors of FeCrAl alloys in liquid lead—bismuth eutectic envirorunents... 

V. Shankar Rao Corrosion Science Characterization of oxide scales grown on 216 L stainless steels in liquid lead—bismuth eutectic... 

Seung Gi Lee HLMC-2013 Corrosion of T91, HT9, and stainless steel 316 L in static cell of liquid lead—bismuth eutectic at 600°C... 

Liquid lead—bismuth eutectic (LBE) [44.5% Pb and 55.5% bismuth (Bi)] in liquid metal-cooled reactors, for example, in Russian Svintsovo-Vismutovyi Bystryi Reaktor (SVBR) and... 

The most commonly used liquid metal is sodium—potassium eutectic. Sodium, potassium, bismuth, lithium, and other sodium—potassium alloys also are used. Mercury, lead, and lead—bismuth eutectic have also been used however, these are all highly toxic and application has thus been restricted. 

Liquid metals are used when temperature requirement is so high that even the nitrate/nitrite salt mixture becomes unsuitable. The most commonly used liquid metal is a eutectic mixture of sodium and potassium (44%). This has a very broad temperature range (40-760°C) and very high thermal conductivity. Lead and lead-bismuth eutectic can be used up to 900° C. There are several disadvantages with the use of liquid metals. Special precautions must be taken while using alkali metals because they react violently with water and burn in air. Mercury, lead, and bismuth-based mixtures are highly toxic, hence their applications are restricted. One common use of liquid metals is in the cooling of nuclear reactors. 

Analysis of the characteristics of liquid-metal coolants, such as sodium (Na), lead (Pb) and lead-bismuth eutectic (Pb-Bi), makes it possible to decide on the coolant for the new fast reactor considered as a basic component of large-scale nuclear power, which will be capable of taking over the greater part of the electricity generation increase and, possibly, of providing for other energy-intensive processes. 

The LFR is a fast-neutron spectrum reactor cooled by molten lead or a lead-bismuth eutectic liquid metal. It is designed for the efficient conversion of fertile uranium and the management of actinides in a closed fuel cycle. 

The CHTR incorporates a passive power regulation system (PPRS) [XXIX-5]. This system includes a gas header filled with helium gas at moderate pressure. The header is attached to a niobium driver tube, which contains lead-bismuth eutectic alloy as driven liquid. The driver tube is housed within a control tube that contains an annular control rod made of boron carbide with niobium cladding. The annular space between the driver and control tube contains lead-bismuth eutectic, on which the control rod floats. The space above the liquid... 

Among liquid metal candidates, mercury (Hg), sodium-potassium (NaK) alloy, sodium (Na), lead (Pb), and lead-bismuth eutectic (Pb-Bi) have been considered and used to build and operate liquid metal nuclear systems. However, liquid Na became the most smdied and used option mainly because it allowed, together with the selection of an appropriate fuel type (e.g., metal or oxide fuel), for a lower doubling time. On the other hand, hquid Hg was abandoned due to its toxicity, high vapor pressure and low boiling temperature as well as poor nuclear and heat transfer properties. More recently, in the framework of Generation IV, the development of fast reactors cooled with liquid metals considers hquid Na but also liquid Pb and liquid Pb-Bi as coolant... 

Liquid metal coolants for fast reactors cooled by sodium, lead and lead-bismuth eutectic, IAEA Nuclear Energy Series, No. NP-T-1.6, Vienna 2012. 

Lead bismuth eutectic Lead-cooled fast reactor Liquid metal embrittlement Oxide dispersion-strengthened (alloy)... 

Liquid metals are considered as efficient coolants in some fast neutron breeder reactor concepts due to their excellent thermophysical and neutron properties [36]. As already mentioned, the Generation IV reference liquid metal coolants are sodium, lead, and lead-bismuth eutectic. Some challenging corrosion issues are also studied in the molten salts and supercritical water environments. 

The uranium-bismuth fuel system is flexible and can be u.sed in many designs. Although other types of liquid-metal systems are certainly possible, the LMFR at Brookhaven is being designed as a thermal reactor in which the fuel is di.ssolved or suspended in a liquid hea y-metal carrier. Ordinarily, the liquid metal is bismuth for highest neutron economy, but other systems such as lead or lead-bismuth eutectic may be used. The moderator is graphite, although beryllium oxide has also been considered. 

Corrosion from molten metals and salts. Zirconium is resistant to corrosion in some molten salts. It also withstands molten metals such as sodium, potassium and the sodium-potassium eutectic used in nuclear reactors. Its corrosion rate is less than 0.025 mm-y in liquid lead up to 600°C, in Hquid hthium up to 800°C, in mercury up to 100°C, and in molten sodium up to 600°C. The corrosion rate is affected by trace impurities such as hydrogen, nitrogen, or oxygen in specific molten metals. Zirconium is severely attacked by molten bismuth, magnesium, and zinc. 

Binary liquid metal systems were used in liquid-metal magnetohydrodynamic generators and liquid-metal fuel cell systems for which boiling heat transfer characteristics were required. Mori et al. (1970) studied a binary liquid metal of mercury and the eutectic alloy of bismuth and lead flowing through a vertical, alloy steel tube of 2.54-cm (1-in) O.D., which was heated by radiation in an electric furnace. In their experiments, both axial and radial temperature distributions were measured, and the liquid temperature continued to increase when boiling occurred. A radial temperature gradient also existed even away from the thin layer next to the... 

The crystallization process for concentrating bismuth in lead by squeezing the eutectic (high in bismuth) liquid out of the solidified high lead portion at a temperature within the melting range of the alloy is seldom used. 

As with azeotropes, eutectics maybe ternary, quaternary, and so on, but their phase diagrams get very complex very quickly. A few important eutectics have an impact on ordinary life. Ordinary solder is a eutectic of tin and lead (63% and 37%, respectively) that melts at 183 C, whereas the melting points of tin and lead are 232 C and 327 C. Wood s metal is an alloy of bismuth, lead, tin, and cadmium (50 25 12.5 12.5) that melts at 70 C (lower than the boiling point of water ) that can be used in overhead fire sprinkler systems. NaCl and H2O make a eutectic that melts at — 21 C, which should be of some interest to communities that use salt on icy roads in the winter. (The composition of this eutectic is about 23 weight percent NaCl.) An unusual eutectic exists for cesium and potassium. In a 77 23 ratio, this eutectic melts at —48 C This eutectic would be a liquid metal at most terrestrial temperatures (and be very reactive toward water). 

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. 

Heat transfer for LMFR. So far as is known, no heat-transfer data have been obtained for liquid bismuth. However, several investigators [10-14] have published experimental heat-transfer results on the bismuth lead eutectic and on mercury. For these results the Lubarski and Koffman equation [15] expresses the results most closely ... 

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