A schoolboy successfully made a nuclear fusion reactor in his family's spare room aged just 12.

Jackson Oswalt, from Memphis, now 14, is believed to be the youngest person to build a functioning nuclear fusion reactor.

The machine was built from customised vacuums, pumps and chambers bought on eBay by his parents - costing the family a total of $10,000. 

His contraption smashes together atoms with enough force to fuse them into one and this process releases energy trapped inside the atoms.  

Information on how to build the machine was found online and on January 19 last year, mere hours before his 13th birthday, nuclear fusion was successful. 

The previous record for the youngest successful mastermind behind a nuclear fusion reactor was held by Taylor Wilson, who achieved it aged 14.