If an ionized fluid flows through a magnetic field, the positive ions will be driven in a direction perpendicular to both the direction of flow and direction of the magnetic field – and the negative ions will be driven in the opposite direction.

If a pair of electrodes are positioned so that one is a “target” for the positive ions and another is positioned so as to be a target for the negative ions, then electrical power will flow through a conductor connecting the two electrodes. This is called the Faraday Effect, named for Michael Faraday who identified the phenomenon back in the 19th century. The general term used for the study of this effect is magnetohydrodynamics and, for obvious reasons, the name is frequently shortened to MHD.

The necessary ionization can be produced by adding an ionizing agent (common table salt might do) to the water.

Here’s a conceptual diagram showing fluid flow, the magnetic field, the electrodes (blue), and a circuit connecting the electrodes:

Most conveniently, the hydradyne has two points at which MHD sections can be incorporated – and those are in the flow restrictors, where the flow is fastest. It could hardly be better suited for the job. I’ve re-drawn the hydradyne showing the dual integrated flow restrictor/MHD sections:

and here is a conceptual cross-sectional view of a restrictor/MHD assembly, showing an electromagnet, the electrodes, and the passage through which the super-critical water flows:

I originally planned to power the engine by concentrating solar radiation on the hot head as shown in this sketch:

It appears to me that the reactor is both scalable and controllable; and that the large ratio between nuclear and chemical reaction outputs implies that a very small portion of a generator's output should be sufficient to produce the needed hydrogen fuel component on demand by electrolysis of water, which means that system inputs would be nickel powder and water, and that the outputs would be copper (transmuted nickel), pure oxygen (the "waste" product of the electrolysis), and heat.

A small LENR generator could certainly provide for the current needs of a village in an undeveloped area – or the full energy needs of residences in any developed area. Equally important, this type of generator can power pollution-free land, sea, and air transport – as well as all kinds of industrial and agricultural equipment.

I decided to not abandon the solar-powered generator but plan to put it on a "back burner" while I investigate the LENR possibilities...

P is used to represent pressure, T is used to represent temperature, and t is used to represent time.

LENR is an acronym for Low Energy Nuclear Reaction/Reactor and, unless otherwise specified, denotes a reactor fueled with filamentary powdered nickel metal and hydrogen gas under pressure.

Ignition refers to a (P,T) point during heating at which the reaction begins to produce significant amounts of heat. It is characterized by an increase in the dT/dt value.

Self-sustaining refers to a (P,T) point at which the reactor will continuously produce heat without external input.

It was while working on the hydradyne electrical generator and needed an autonomous test heat source to maintain the working fluid (water) in a supercritical state that I learned of Andrea Rossi's success with producing heat with a small LENR device. According to what I read, 50 grams of nickel in a hydrogen-filled tube was heated to start a self-sustaining reaction which produced 4.7 kW of heat continuously for six months.

The physics community appears unable/unwilling to do more than speculate about the specifics of the reaction. I’m neither physicist nor engineer, and am interested only in the safe production of heat for my electrical generator project.

Rossi has reported one lab explosion, and I have heard an unverified rumor of an explosion elsewhere that resulted in the death of a lab worker. I have read that an LENR may exhibit unstable behavior at startup and shutdown. I have heard also that instability may increase as the device output is increased, and have noted that Rossi's solution for higher outputs has been to use multiple small devices to avoid the instability problem.

I’m assuming that all of the information above is true. I’m assuming that the design variables are (1) the total surface area of the nickel, (2) the pressure of the hydrogen in the reaction chamber, and (3) the temperature in the reaction chamber.

I’m proposing an hypothesis that the reaction rate can be controlled by modulating the pressure of the hydrogen gas in the reaction chamber, and that the reaction can be immediately and completely stopped by evacuating the hydrogen gas fuel component (opening a connection between the reaction chamber and a vacuum tank).

Objective 1: Throughout, record accurate measurements of pressure, temperature, and radiation count at least once each second, and all test/control actions in real time.

Objective 2: Verify that an LENR can be made to operate as described in the various reports – that it has a detectable ignition point and can be brought to self-sustaining operation.

Objective 3: Verify the hypothesis that an LENR can be shut down by evacuating the hydrogen gas from the reaction chamber to a vacuum tank.

Objective 4: Verify the hypothesis that the reaction rate of an LENR can be controlled by modulating the hydrogen gas pressure once a self-sustaining reaction is underway.

Objective 5: Run a sequence of tests at increasing pressures to find the ignition and self-sustain (P,T) points, and produce equations describing these loci.

Objective 6: Increase the amount of nickel (to increase the surface area) to determine if there is a proportional increase in output power, and verify that the reaction rate can be controlled as before.

Objective 7: Conduct the same series of experiments with the other metals (there are about a dozen of them) that also appear suitable for this type of LENR.

Objective 8: Provide sponsors with working reactors, containment vessels, and/or documentation/data according to level of project support provided.

This tiny (3½-inch long) LENR consists of a stainless steel tube with one capped end and the other plugged with a small electric heater. Just ahead of the electric heater a small stainless steel tube feeds hydrogen gas into the reactor tube. The remainder of the reaction chamber is filled with very finely powdered nickel.

I’m attempting to produce a simple (no catalyst/buffer) LENR and exercise dynamic (computer-mechanical) control of the pressure and reaction rate. I’m hoping to use what I learn to design and build single reactors with much larger (greater than 100kW) outputs as an intermediate step to very much larger (more than 1MW) reactors.

Here’s a conceptual (not to scale) sketch of my test reactor...

...and here’s a (to scale, inches) drawing of the planned stainless steel prototype containment vessel.

Another pair of views (without the threaded end cap or H₂ inlet)...

and a photo of the 200w cartridge heater that fits into the center of the containment vessel and is used to heat the reactor to the ignition point:

In addition to the reactor tube and heater, we’ll need a temperature sensor so we can monitor reactor activity, a source of electricity, a switch to turn the electric heater on and off, a supply of hydrogen gas, a valve to control the flow of gas into the engine, and a valve to control evacuation of the gas in the reaction chamber to a vacuum tank.

To ensure precise and rapid control I’m using an Arduino Mega 2560 microcomputer (above) to

• control the heater power relay (RY)
• control the hydrogen delivery pressure (Stepper)
• protect the hydrogen pressure regulator (V1)
• adjust reactor hydrogen pressure (V2)
• dump hydrogen to vacuum tank (V3)
• control the hydrogen flow at the reactor (V4)
• monitor reactor hydrogen pressure (P)
• monitor reactor temperature (T)
• monitor a Geiger counter
• record reactor operating parameters and all control activity
• set run/stop status
• set nominal operating temperature
• set safety threshold temperature
• display complete reactor status in real time

For safety I’ll program the microcomputer to automatically turn off the heater, shut off the supply of hydrogen, and evacuate the reaction chamber if the temperature reaches a pre-set safety threshold.

Initially, heat to start the reaction is provided by the electric heating element – but as the reaction proceeds, the energy released raises the temperature enough so that the reaction is self-sustaining when the heater is turned off.

During testing, heating will be controlled by programming the microcomputer to vary the duty cycle of the electric heating element according to the test target temperature, the current temperature, and a program variable that determines how aggressively the heat is to be applied. Here's a plot of the duty cycle with a target temperature of 200°C for sixteen levels of "aggression":

To shut down the reactor, all that’s needed is to reduce the hydrogen pressure and/or lower the temperature below the minimum requirements for operation.