Lockheed Martin Corp says it has made a technological breakthrough in developing a power source based on nuclear fusion, with reactors small enough to fit on the back of a truck.

The aerospace and security firm, which made the announcement Wednesday, says it expects its first operational reactor to be ready in as little as 10 years.

And thanks to the reactor's smaller size, the company based just outside Washington in Bethesda, Maryland, said it can design, build and test the new compact fusion reactor in less than a year.

After completing several of these cycles, Lockheed's team said it plans on being able to produce a prototype in five years.

"Our compact fusion concept combines several alternative magnetic confinement approaches, taking the best parts of each, and offers a 90 percent size reduction over previous concepts," said Tom McGuire, compact fusion lead for the Lockheed Martin Skunk Works' Revolutionary Technology Programs.

The Skunk Works team also plans to search for partners to help further the technology.

Roger Dargaville, a research fellow and leader of the MEI Energy Futures Group at the University of Melbourne, Australia, stressed that nuclear energy will be an important part of power generation in countries where other low carbon alternatives are not viable.

"The potential for the use of fusion reactors over fission is exciting news as the dangerous by-products of fission reactors are a major disadvantage of the technology," said Dargaville.

But, he added, "The lack of political will to address the general resistance to nuclear power within the population means the option for using nuclear will come too late."

Lockheed's announcement is still a "long way" from a working prototype or commercially viable power generator, said Joel Gilmore of Australia-based ROAM Consulting.

"Fusion requires incredibly high temperatures and pressures, which is challenging, and a lot of people have been working on fusion for a long time. So I won't get too excited yet," he said.

"Even if successful, the big question is what will fusion power cost? It will be challenging to compete with the falling costs of conventional renewable energy sources, especially in Australia with our world class wind and solar resources."