Sodium advanced high temperature

Session 4 focused on recent advances in the thermochemical copper chloride and calcium bromide cycles. Much of the current research on thermochemical cycles for hydrogen production involves the sulphur cycles (sulphur-iodine, hybrid sulphur), however, these cycles require very high temperatures ( 800-900°C) to drive the acid decomposition step. The interest in the Cu-Cl and Ca-Br cycles is due to the lower peak temperature requirements of these cycles. The peak temperature requirement for the Cu-Cl cycle is about 550°C, which would allow this cycle to be used with lower temperature reactors, such as sodium- or lead-cooled reactors, or possibly supercritical water reactors. Ca-Br requires peak temperatures of about 760°C. Both of these cycles are projected to have good efficiencies, in the range of 40%. Work on Cu-Cl is ongoing in France, Canada and the United States. Work on Ca-Br has been done primarily in Japan and the US, with the more recent work being done in the US at ANL. The papers presented in this session summarised the recent advances in these cycles. 

Like taste, touch is a combination of sensory systems that are expressed in a common organ—in this case, the skin. The detection of pressure and the detection of temperature are two key components. Amiloride-sensitive sodium channels, homologous to those of taste, appear to play a role. Other systems are responsible for detecting painful stimuli such as high temperature, acid, or certain specific chemicals. Although our understanding of this sensory system is not as advanced as that of the other sensory systems, recent work has revealed a fascinating relation between pain and taste sensation, a relation well known to anyone who has eaten "spicy" food. 

Instrumentation. The optical characteristics of the liquid-salt coolant and recent advances in optical technologies may result in major improvements in instrumentation capabilities relative to those used in existing sodium-cooled and high-temperature reactors. 

The high temperatures will require special considerations in the design of the refueling machines and will likely require that the fresh fuel be preheated before refueling. These features exist in refueling machines for sodium-cooled fast reactors such as the Fast Flux Test Facility (Sect. 5 and Appendix A) and in refueling machines for the British Advanced Gas-Cooled Reactors (Sect. 4.3). 

The most advanced system of this complex is the sodium/sulfur battery. Cost estimates on high-temperature batteries show that after the development phase has been completed and prototypes tested, these systems may operate well inside economical margins, assuming that mass production starts. In case these vehicles and their batteries are only produced in small numbers, the same problem will be at hand, as already discussed with the lead-acid battery. A deficiency of mass production makes vehicles and batteries artificially expensive. 

The main interest in high temperature batteries such as lithium/iron sulfide, sodium/ sulfur, and sodium/nickel chloride is for electric vehicle applications due to their high specific power and energy possibilities. The replacement of the liquid lithium electrode with a solid LiAl alloy alleviated many of the safety concerns that plagued the other two systems, which are based on a liquid sodium electrode. In 1991, the United States Advanced Battery Consortium (USABC) selected the bipolar molten-salt LiAl/FeS2 battery to be developed as... 

These measures are expected to be more realistic by introducing some innovative technologies such as Mod.9Cr-lMo steel with high strength at high temperatures, advanced elevated temperature structural design standards, two-dimensional seismic isolation, and a re-criticality free core as well as by taking the desirable characteristics of sodium coolant such as operability in a low-pressure system and excellent heat transfer characteristics into account. 

VHTR, very high temperature reactor GFR, gas-cooled fast reactor GCR, gas-cooled reacts AGR. advanced gas-cooled reactor CANDU, CANada deuterium uranium SFR, sodium-cooled fast reactcn. ... 

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