Thorium cycle This blog is a slightly modified Google-translation of the original text found on

Thorium is, as elsewhere mentioned, actually not radioactive. But by absorbing one of the neutrons, subsequently formed in the process, it will transform into an uranium isotope, which by itself is a better fuel in nuclear reactors other than what is used today.
A reactor based on thorium must therefore be started with a temporary neutron source.

Essentially the use of thorium as a nuclear fuel is not something new. But for many years, the technology has been overshadowed by the developments based on uranium.
In India, efforts are apparently concentrating on a further development of existing technology with water as moderator. – A little more later.

In China and other countries, “they are going the whole step forward” and dissolve the fuel in molten salt.
Along with the great advantages, there are of course new challenges.

Here it is necessary to go a little more in details with the technical.

  • The neutrons generated in the core processes are fast and should be slowed down (moderated) to be able to take the process further.
    Therefore we must use a moderator, which in almost all existing reactors it is water.
    Just as in common (coal-fired) power plants, the water will be under pressure and in nuclear power plants; this requires a strong containment to withstand the pressure.
    For nuclear reactors, it should accommodate the entire reactor and is a major challenge, both technically and economically.
  • A few times one speaks of ‘fast reactors’. However, it is not the reactor that is fast but the neutrons that are part of the process that are fast – not moderated.
    These reactors will again differ from ‘everything else’ and must be cooled with liquid metal, for example, lead.
    Experimental reactors are working in several countries, but so far this is mostly a theoretical possibility.
  • If the fuel is dissolved in molten salt and using graphite as moderator, the process need not to be under pressure (maybe a slight vacuum). Thus, one can avoid the large and costly pressure vessel. Additionally, it provides the opportunity to operate at higher temperature and get a better utilization of the fuel.
  • Neither thorium nor molten salt is something new. It has been tested in several places with confidence.
    Although the use of molten salt goes well with the use of thorium, it must not be forgotten that thorium can be used without molten salt and molten salt can be applied without using thorium.
  • As we are getting better knowledge of the processes involved in nuclear reactions and heve got completely different computers, it is now possible to simulate forward to a much better design.

Nixon On the Oak Ridge Laboratory in Tennessee a test-reactor ran for 4 years without problems, but was stopped by Nixon.
It is alleged that he was more interested in nuclear bombs.
Atombombe Eksploderer

Countless articles in the media and on the Internet give long explanations and highlights the huge benefits while there are few objections, mostly related to the numerous and long-term studies that will be needed.

Of course, you will also see the usual protests that testify inability or unwillingness to communicate the facts.

Nuclear power, making use of thorium in the molten salt, differ fundamentally from the prior designs, making use of uranium.

  • As already mentioned, there will be no need to keep the core physical process under pressure. In addition to the savings it will open many other benefits.
  • As the fuel is already liquid, there is no risk of core melt which, although trumpeted in the media, does not need to be a disaster.
  • On the other hand reactors, based on molten salt will be “inherently safe” and have “passive safety”.
    This means that there is no need for anything other than the force of gravity to let the fuel flow down to a safe position in the event of an incipient overheating.
  • As mentioned elsewhere, known reserves of thorium are significantly greater than known reserves of uranium. This, along with the thorium is utilized 100%, meaning that there will be plentiful and cheap energy for thousands of years.
  • Not only will reactors based on thorium, be more efficient. They will also be able to utilize existing waste from uranium based reactors.
  • If you look a little on the arithmetic and remember that what is termed as waste, still contains approximately 95% of the initial energy.
    This waste, along with the depleted uranium, also is waiting, will, along with what is surely comming, can deliver plenty of energy for perhaps hundreds of thousands of years.

There will obviously be a need for new and costly experimental facilities. Perhaps most to find appropriate materials and not so much to control the core physical processes. Such a reactor should last 60 years, as long as the known reactors that are based on uranium.
It is therefore possible that investors feel that we have already invested huge sums in developing reactors based upon uranium and now, finally have gotten through all the initial problems.
“What we have this we know, it works well – There is inexpensive uranium to a few hundred years – Why so suddenly start something new?”

Yet we are gathering momentum in the development.

Luftforurening Kina - Langt ud over havet

  • In China, where air pollution reaches far out at the sea, there is a desperate need for clean energy.
    In addition to a very extensive program of ‘traditional nuclear’, work is going on, with the support of Bill Gates, on a more advanced design using molten salt.
  • Perhaps Europe has seen that you can not continue and just wait.
    Apparently, one will try to team up and work on a project also based on thorium from molten salt: SAMOFAR
  • In India, where there are good deposits of thorium, work is going on using thorium in connection with the further development of known design, wherein a mixture of thorium and uranium is used in an existing type of reactor, modified for the purpose.
  • Norway is so small started.

Niels BohrIn Niels Bohr’s homeland, where the word atom has been a dirty word, work is going on to clarify the opportunities and challenges associated with a modular design of small reactors that can be produced centrally and when finished can be installed where necessary.
This will mean that small reactors may be “of the shelf”. After use, they can go back to the supplier for upgrade, recycling or disposal.
Thorium er FremtidenThere are good reserves of Thorium in Greenland and in Norway and it is tempting to say that in Denmark we should go ahead and be a pioneer of cheap and clean energy that does not depend on changing sun and wind.

Especially in Denmark there has been built up public sentiment against nuclear power.
Although this resistance is based on extremely dubious arguments, it must be faced that, apart from importing electricity, nuclear power based on uranium will be a very long way off. Thus, it would seem logical to wait for “the other” (China) has developed commercial use of thorium.

It is to be hoped that it will not last too long and that the “No No No people” do not want to ruin also this obvious opportunity for cheap and polluting energy.


This blog can be seen as an addition to something else I’ve written with the aim of eliminating some of the many erroneous ‘information’ and tenacious myths that have arisen about nuclear power.

It has not been my intention to cover more than a minor part of the enormous opportunities opening up for the use of thorium in future energy supply.
As I in no way have more than ordinary skill in the area, I would be grateful for bug fixes and suggestions for changes.
Write to me at

Yours impatiently waiting
Thorkil Søe