Flexible Conversion Ratio Fast Reactor Systems Evaluation

Abstract

This is the final report under award DE-FC07-06ID14733, Project No. 06-040. Conceptual designs of lead-cooled and liquid salt-cooled fast flexible conversion ratio reactors were developed. Both concepts have cores rated at 2400MWt placed in a largepool-type vessel with dual-free level, which also contains four intermediate heat exchangers (IHXs) coupling a primary coolant to a compact and efficient supercritical CO 2 Brayton cycle power conversion system. Decay heat is removed passively using an enhanced Reactor Vessel Auxiliary Cooling System (RVACS) and a Passive Secondary Auxiliary Cooling System (PSACS). The most important findings were that (1) it is feasible to design the lead-cooled and salt-cooled reactor with the flexible conversion ratio (CR) in the range of CR=0 and CR=1 in a manner that achieves inherent reactor shutdown in unprotected accidents, (2) the salt-cooled reactor requires Lithium thermal Expansion Modules (LEM) to overcome the inherent salt coolant's large positive coolant temperature reactivity coefficient, (3) the preferable salt for fast spectrum high power density cores is NaCl-KCl-MgCl 2 as opposed to fluoride salts due to its better thermalhydraulic and neutronic characteristics, and (4) both reactor concepts achieve about 30% higher power density than the gas-cooled fast reactor, but attain power density 3 times smaller than that of the sodium-cooled reactor.

Fluid Mechanics of Liquid Metal Batteries

“…Properties of common electrolyte materials, from Janz et al [114,115] Todreas et al [116], Kim et al [11], and Masset et al [117,118]. [15].…”

Metal pad roll instability in liquid metal batteries

“…We use here a simple cell model of height and diameter h = d = 10 cm, with a 1 cm thick electrolyte layer and 4.5 cm thick electrodes. Denoting the upper metal by 1, the electrolyte by 2 and the lower metal by 3, the densities are [39,6,40] The mutual interface tension between the two phases i and j can be estimated using the surface tensions of phase i and j as [41] i.e.…”

“…We use here a simple cell model of height and diameter h = d = 10 cm, with a 1 cm thick electrolyte layer and 4.5 cm thick electrodes. Denoting the upper metal by 1, the electrolyte by 2 and the lower metal by 3, the densities are [39,6,40] The mutual interface tension between the two phases i and j can be estimated using the surface tensions of phase i and j as [41] Figure 5: Illustration of the deformed interface due to metal pad rolling for B z = 10 mT (a) and minimal height of the electrolyte layer for different magnetic background fields and J = 1 A/cm 2 (b). The minimal distance between the two interfaces shown in (b) rotates; for the rotation period see figure 6.…”

Sloshing instability and electrolyte layer rupture in liquid metal batteries

“…Physical dimensions and properties of an Mg|NaCl-KCl-MgCl 2 |Sb cell11,72,73 . .96 · 10 −7 8.66 · 10 5 0.37value (approximately 200 times the magnetic field of the earth) is chosen in order to evidence clearly the effect of metal pad rolling.…”