It might be that the LENR reaction wants to run hot at just below 3000C. This could be why Rossi has had problems with burnouts over the years when the balance between cooling applied to the LENR reactor's structure and LENR heat production is lost. It may be that a LENR reactor that loses cooling of its structure will fail when the temperature of the plasma produced by LENR begins to rise to its stability point at 2700C.
Rossi's solution to the reactor meltdown problem as deminstated by the QuarkX is to ensure that his reactor can survive the highest temperature that the LENR reactor can produce. This could mean that any LENR reactor that depends on external cooling to keep its operating temperature under the LENR reaction stability temperature is subject to meltdown if the external cooling is lost. Rossi's sigma 5 testing could be a method to check high temperature endurance in the Quark structural material. One thought that I have in the back of my mind is that the SunCell reaction can sustain a self-sustaining plasma for minutes on end without any external stimulation of energy input. This indicates that a plasma can reach a state of equilibrium where it can maintain its own temperature that does not increase beyond a certain stability point. Similarities between systems sometimes lends insights into their underlying mechanisms. Could the QuarkX be a tiny version of the SunCell? If so, this insight could imply some important reactor design principles. For example, it is interesting that the boiling point of nickel and the 2700C operating temperature of the QuarkX are the same. It might be that the stability temperature of the plasma based LENR reactor can be set through the use of the metal used in its electrodes. For example, a QuarkX using silver electrodes might have a stable plasma temperature at 2200C which happens to be the boiling point of silver. An alumina tube in a QuarkX configuration just might be able to handle that operating temperature. There could be a relationship between the boiling point of conductive metal used in the reaction and melting point of the insulating structural material used to confine that metal plasma. Brian Ahern has given us critical insight into the underpinnings of LENR when he postulates that nanoparticles are central to the LENR reaction. But there particles must be energized when they are newly formed during condensation out of vapor. use the link below to find the boiling point of elements http://periodictable.com/Properties/A/BoilingPoint.st.log.html A lead electrode might be in the operating range of alumina at lead's boiling point of 1800C. Just to give himself some operational safety factor, Rossi may be using Boron Nitride (melting point -> 2,973 °C) for the structural tube for his QuarkX reactor. The SunCell is sure to melt down when tungsten is used as its electrode metal with a boiling point of 5555C. Using silver makes for a colder reaction. If you use tungsten in your reactor you are asking for a meltdown. A zirconia tube (2,715 °C) might be able to handle a nickel electrode. A zirconia tube will handle a silver electrode boiling temperature for sure. An aluminum electrode (2519C ) used with a zirconia tube looks like a good match with some meltdown safety factor tossed in. This apparent materials michmatch Rossi may have had some meltdown issues when he started out using an alumina tube in his hot cat. If you want to use lithium aluminum hydride to supply your hydrogen, it might be wise to use a zirconia tube. If you use titanium(3287C) hydride for your hydrogen, you are askings for a meltdown.
