How does a Tokomak reactor work:
Tokomak is a kind of reactor like all other reactors that we have in our plants like PWRs,
Breeders and etc.
The problem is, most of the time we don’t have an easy and good description for this
structure specially about its way of working.
Tokomak’s action is based on magnetic fields therefore , first of all Hydrogen plasma
(fusion factor ) is being set among toroid and then for creating magnetic field ,toroid
motion of plasma among toroid’s space and reaching to the special temperature ( about
100 million Kelvin -that we need for fusion), we should make about 8600000 Volt for
this kind of reactor but only in a pulse mode ,if we don’t obey this rule ,we will destroy
As we make this much voltage, we will make current in the toroid of Tokomak which
can ride plasma in the way of its magnetic field.
Now plasma acts as a toroid by itself, in this case if we suppose that the direction of
current correspond to the direction of plasma (example: to the right-in picture), created
magnetic field will be toroid and its direction is upward (according to the picture).
Manufacturers build the design of this reactor in a special shape: means by the time the
direction of magnetic field is upward for example Tokomak will make a current in
horizontal toroid (outer toroid) which can create a field but in downward direction, so the
resultant of these two forces will be zero.
Upward field +downward field = 0
In this position, plasma won’t change and has its own shape.
As the voltage of Tokomak increases, the temperature of our system will be increased
too till it reaches to the special temperature that we need for fusion, by this time fusion
the prominent differences among this reactor and others are:
• First: Tokomak is being used for fusion and others (PWRs, Breeders, CANDU…)are
• Second: It is being used in labs and because of this we need high voltage for its
striking up, therefore reactors which are being used in plants don’t need high voltage for
working so they start by breaking the nuclei of some special fuels.
• Third: you can separate Tokomak’s special devices and set them up again .but if you
try this action for fission reactors, they will completely destroy.
By all declarations which have been said, although tokomaks are experimental reactors
but they can be the most beneficial ones.
Understanding their mechanism for working can help us to figure their benefits out
• Written by: Mahsa Mehrangiz