What is LENR?

The acronym 'LENR' stands for Low Energy Nuclear Reaction, which describes a physical phenomenon first detected in the early 1900s which, under the name ‘Cold Fusion’ captured the world’s attention in 1989 after the publication of some controversial experimental results by Martin Fleischmann and Stanley Pons.

The old 'Cold Fusion' tag came about because in the early days researchers thought there must be a fusion process occurring.

In the modern name for this field of research, 'Low Energy' means that a nuclear reaction is happening at pressures and temperatures far below those considered to be necessary for nuclear reactions by many scientists.

This is already one of many contradictions between LENR and generally accepted scientific concepts, which insist – based on mathematical and physical calculations that nuclear reactions need a specific (and high) energy to occur. This is why LENR research is often called 'fringe science' and the results of many thousands of experiments dismissed as they 'cannot be true'.

To understand why many physicists today deny that LENR is real, we need to have a quick look at current understanding of the structure of an atom, what it is made from, and how it behaves.

Nuclear physics crash course

Important note: The following description is simplified and very general, in fact not quite correct, but it is intended to enable readers with a limited knowledge of atomic physics (which would include quite a few members of this forum) to understand a little more about the reasons for the scientific controversy which surrounds LENR.

An atomic nuclei consist of

  • Protons, which are electromagnetically positively charged.
  • Electrons, which are electromagnetically negatively charged.
  • Neutrons, which have a electromagnetically neutral charge

The number of protons inside an atomic nucleus tells us which element it is (e.g. Hydrogen, Helium, Oxygen, Iron...).

The number of neutrons inside an atomic nucleus indicates which isotope of the specific element it is.

'Isotope' is the term used for atoms where a differing number of neutrons in the nucleus give us two or more forms of the same element that differ in relative atomic mass but most often not in chemical properties. A good example of this is given by Carbon, which has two isotopes. C12, and C14. Both exist in nature, but very stable C12 predominates. C14 is a radioactive form of an element which in almost every other respect behaves just like C12.

Another (important in LENR) isotope example is given by Hydrogen. This is the smallest atom with just one proton in its nuclei. It has three known isotopes

  • Protium (1 Proton, no Neutron), which is the most common type of Hydrogen here and in the whole universe. Two atoms of Protium chemically bonded to Oxygen make H2O, which we call 'water'.
  • Deuterium (1 Proton, 1 Neutron), which is stable but much rarer – this combines with Oxygen to make D2O – called 'heavy water'.
  • Tritium (1 Proton, 2 Neutrons), which is radioactive and thus unstable - but has similar chemical behaviour to the other two isotopes.

Now, you may remember from your schooldays that like charges repel (think of two magnets, N pole to N pole.), and opposite charges attract. As for common magnets, so it is for electromagnetic charges. This 'like charges repel' rule means that an atom with only multiple protons in its nuclei would instantly undergo a 'fission' (breaking apart) reaction. This would happen because the protons would mutually repel, splitting this ‘impossible’ atom into smaller atoms with more stability.

Here we have to remember the famous four fundamental forces of the universe. You will need to know a little about all of these!

  • Gravity
  • Electromagnetism
  • Weak Nuclear Force
  • Strong Nuclear Force

As you see, two of the four are called 'nuclear forces', a weak one and a strong one.

The strong nuclear force (with the help of the neutrons) binds the repelling protons together inside an atomic nucleus and it is stronger than the electromagnetism force, which would cause the atom to fission (break up).

Side note: The strong force has a 'binding energy'. This binding energy is the energy which is released in todays fission based nuclear plants, where (for example) a big atom like Uranium is split by shooting neutrons at it. This causes the release of fast moving particles (radiation) and lots and lots of heat energy.

Simply said: The larger the nucleus, the more difficult it is for the strong nuclear force to keep the repelling protons together. At a specific atom size it is already enough to hit the nucleus with an accelerated neutron (which is not repelled by the nucleus and can easily hit the nucleus) to split the fragile nucleus into several smaller elements. Such atoms or isotopes are called 'radioactive' elements.

There is a problem here: The nuclear forces only act over very short distances. Electromagnetic forces can be felt (and used) over huge distances, for example in radar, radio telescopes and mobile phones, while the nuclear forces only have a range of a few femtometers. In case you don’t know, a femtometer is 1 quadrillionth of a meter!

This means you have to bring the charged particles very close together, so that the strong nuclear force can bind them to the nucleus. When this happens, we talk of the famous nuclear fusion!

Nuclear fusion

The step of 'bringing them close together' needs a lot of energy! If you want to add a proton to the nucleus of an element (perhaps to make Deuterium into Helium) you have to put that a lot of energy (in the form of kinetic acceleration) into the proton, so that it can overcome the accumulated repelling electromagnetic force of all the protons already inside the nucleus. This resistance stopping the extra proton joining the others is called the 'Coulomb wall' or 'Coulomb barrier' – that is the obstacle that must be overcome.

A machine that can do that – like the Large Hadron Collider at CERN - needs to be huge and requires enormous amounts of electrical energy to accelerate protons (for example) to speeds where they can break the wall.

Nuclear fusion events create an energy release in the form of a 'mass deficit'. The energy released by such a 'mass loss' can be calculated using Einstein’s famous formula E = m*c2.

In this formula, c = the speed of light in meters per second (299.792.458 m/s), and m = the mass lost in kilos.

Since c * c is such a HUGE number, it will be apparent even a minute quantity of mass is equivalent to a huge amount of energy (E)!

Because fusion is most powerful when 'constructing' larger atoms from very small ones with a 'small' repelling force (e.g. Hydrogen to Helium), there is little to no long-term problem of creating harmful radioactive waste. This is why scientists are very interested in making this type of energy usable for mankind.

Simply said: They want to convert thermal energy released in the fusion process to the electrical energy that ends up in our wall sockets.

But there is the 'barrier-jumping' problem created by the existence of the Coulomb wall, which is the reason why 'hot fusion' based power plants - like Zeta in the UK - are not able to produce more energy than is needed to make fusion happen inside their reactors. Thus we say the Coefficient of Performance (COP) of these machines is less than 1, or COP < 1.

LENR promises a way of doing a similar thing on your kitchen table!


In the early days of LENR the involved researchers thought they saw a fusion process with very low energies needed to trigger it. In other words, COP > 1!

The researchers assumed a fusion process because they saw excess energy in form of heat and some nuclear changes. They also saw elements which weren't there before the reaction.

These two characteristics are also present in the huge 'hot' nuclear fusion plants.

There is also another problem with the radiation: While hot fusion processes release also harmful radiation in the form of fast neutrons, the cold fusion process did not.

But physicsts agree that each time a atom changes its structure in any way, radiation has to be seen, at least as an indicator.

And here begins the big contradiction which made massive waves in the early 90s!

A long story cut short: The announcement of cold fusion by Pons and Fleischmann started a long and very rancorous debate in the scientific community. In the end, because of a very low experimental replication rate, the LENR file was officially closed by large scientific institutions, written off as 'experimental error'. That is why continuing research (and those who carry on working in the field) are widely regarded as being 'fringe science' and not altogether respectable.

Because of this 'reputation trap' you have to be careful at this stage if you want to investigate the topic on your own!

While sounding this cautionary note it must be said that a lot of LENR-related material you may find in the internet is not very scientific and often has a esoteric touch!

Keep that in mind and don't believe anything before you cross check all the facts.

However, some reseachers continued to study the LENR process and few of them are able to reproduce experimental results with a COP > 1.

Most of these 'positive' results are achieving only a very little excess energy (in the range of mW). And because it is very difficult to measure thermal energy properly (see calorimetry), there are many doubts in the scientific community that such positive LENR experiments only had some measurement errors.

Anyway, if you assume LENRs to be real, they cannot be fusion reactions like physics understands them today. Instead they must be something other not yet seen or theoretically described.

In these days there are many different attempts to describe in scientific way what LENRs could be and how they could work in detail. This is called a 'theory'.

Some theories are using classical physical concepts, others are using concepts of the relatively new area of quantum mechanics.

The most popular theory is the 'Ultra Low Momentum Neutron Catalyzed Nuclear Reactions on Metallic  Hydride Surfaces' by Allan Widom and Lewis Larsen, often just called the 'Widom-Larsen-Theory'. It was published in the peer reviewed 'The European Physical Journal C' and therefore arouse also the interest of serious researchers at NASA. The Widom-Larsen theory in general was the first theory which delivered an physically correct and accepted explanation why the concept of LENRs may not necessarily be total mischief or pseudoscience. Since that publication LENR got again a slight boost in serious experimental work.

The Widom-Larsen theory

The theory makes the assumption that inside a metall lattice the electrons of the metall atoms can be set into a collective motion, like collective swaying to music, but to electromagnetic frequencies.

By this technique it could be possible to accelerate the electrons with relatively less input energy, so that they get theoretically larger or heavier (keep in mind that mass is nothing else than energy in a solid phase, as described by E = m*c2!).

The larger the electron becomes, the more probable it is that a so called 'inverse beta decay' occurs. This means a proton (like from hydrogene which was soaked into the lattice before) could capture the electron ('electron capture') and become a neutron.

We know that a neutron is an uncharged particle and able to enter an atomic nuclei without overcoming a barrier. When this happens, for e.g. the neutron is added to a Nickel or Palladium nuclei, the weak nuclear force would resolve the neutron excess in this nuclei by splitting one neutron into an electron and a proton again. While the electron then moves to its orbit around the nuclei, the proton will stay inside the nuclei, bound by the strong force, which lets the element shifts in the periodic table.

The latter type of reaction is called 'beta minus decay' and generelly known as 'nuclear transmutation'.

According to the Widom-Larsen theory it could be possible to create free neutrons with less input energy than is released by the following reaction chain when this neutron is captured in a nuclei (COP > 1).

The word 'could' is highlighted a few times in the description above, because this are highly theoretical assumptions and if you look at the mathematics behind, there is a lot of probability involved.

The follwing youtube video will give you further insights into the story of LENR:


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