A number of issues with this article...

Tritium is not hard to make. It is easy (and thus inexpensive enough), that we used to have tritium dial watches, rifle scopes and other devices. If you have a reactor, you can make tritium - just add some Lithium. Russia has lots of reactors.

Fission bomb energy is not related to nuclear decay, but rather is a result of the fissioning (splitting) of U-235.

Thermonuclear weapons do not have to be big, or high yield It is possible to make them very small, to where the US deployed them as tactical weapons. I used to be a crew member in a patrol plane that carried thermonuclear depth charges, with a maximum yield of 10kT, for example. But those were huge compared to the entire re-entry vehicle of a modern thermonuclear warhead. Take a trip to the Nuclear Weapons Museum in Albuquerque to see a model of these.

Thermonuclear weapons may or may not have tritium. But they typically get the bulk of their energy, not from the fusion reaction, but from rapid fission resulting from the neutron flux from the fusion reaction bombarding a uranium rod. In that sense, they are three stage: fission trigger, fusion neutron source, fission third stage.

There are also two primary kinds of thermonuclear weapons: the "hydrogen bomb" - which is the three stage I meantioned - Teller-Ulam design; and "boosted fission" - which is probably what the North Koreans detonated and used for their credible H-EMP threat.

The boosted fusion design is simpler than a classic thermonuclear weapon - it is a spherical implosion fission bomb, with some tritium or deuterium added (in one form or another) to get a small amount of fusion which boosts the fission. These don't have the scalability of a classic thermonuclear weapon, which has been tested up to the 50 MT range, but are more powerful than typical fission weapons - say, 250kT.