Key nuclear international institutions on Monday signed a deal to step up their collaboration, marking a step forward in the development of a multibillion dollar experimental nuclear fusion project.

The accord was signed in Geneva by International Thermonuclear Experimental Reactor (ITER) Director General Kaname Ikeda and Yury Sokolov, the deputy director general of the UN's nucler watchdog, the International Atomic Energy Agency (IAEA).

The agreement would strengthen the exchange of information and training of scientists between the two organisations.

"The exchange in experience is very important," Sokolov said.

The ITER thermonuclear project aims to research a clean and limitless alternative to dwindling fossil fuel reserves by testing nuclear fusion technologies.

Instead of splitting the atom -- the principle behind current nuclear plants -- the project seeks to harness nuclear fusion: the power of the sun and the stars achieved by fusing together atomic nuclei.

If it is successful, a prototype commercial reactor will be built, and if that works, fusion technology will be rolled out across the world.

The EU, Japan, China, India, South Korea, Russia and the US are involved in the experimental project, with the reactor currently under construction in the south of France, at Cadarache.

"The need in energy is so huge that our efforts for ITER... is not a waste of money," said Solokov.