The latest item to come in the mail for Steven Udotong looked a bit like a shower curtain ring.
Except that it was made from steel and rubber, and it joined a growing collection of gadgetry you would not find in any bathroom: a vacuum pump, a stainless steel orb the size of a grapefruit, stout metal flanges, and lengths of titanium wire.
"I've been waiting for this for a while," he said of the steel ring.
Udotong, 16, a junior at Cinnaminson High School, is building a nuclear fusor in his basement.
What that means is this: if all goes well, by the end of summer the South Jersey teen will be able to drive hydrogen atoms together with terrific force inside the steel orb, fusing them into helium and thereby producing a small amount of energy.
This is not nuclear fission, the atom-splitting reaction at a nuclear power plant that yields radioactive waste. It is fusion, a very small-scale version of the process that takes place in the sun. Scientists around the world have spent decades pursuing fusion as a solution to the world's energy woes, as it would be a waste-free, emission-free, and virtually inexhaustible source of power.
The big hurdle is that for now, such devices take more energy to run than they produce.
Udotong is not going to solve that problem, at least not with the contraption in his basement.
But his efforts have caught the eye of people at Princeton Plasma Physics Laboratory, where scientists have built an 85-ton, two-story "tokamak" – a chamber for testing various elements of the fusion process.
Andrew Zwicker, a physicist and the head of public outreach at the laboratory, funded by the U.S. Department of Energy, met Udotong at a science education banquet in Burlington County.
"His device isn't going to revolutionize the world," Zwicker said. "But he might."
Udotong learned about fusion in 10th-grade chemistry and researched the topic further on his own, finding his way to an online community of fusion buffs at www.fusor.net. The site contains a wealth of instructions and a forum where "fusioneers" can trade tips – most of them adults, but also the occasional high schooler who takes on the ambitious project.
Udotong's mother, Nonye, has taught physics at Rowan University, so she welcomed his interest.
"I'm not going to be the one to say no," she said.
But his mom, who emigrated to the United States from Nigeria more than two decades ago, did not truly think her son would pursue it – until the packages began arriving.
He set up a GoFundMe page to raise money, and he enlisted one of his four brothers – Isaiah, a junior at Massachusetts Institute of Technology – to place orders for parts online. (He posted that he would be the first African American student to complete such a project, though his mother said they did not know for sure.)
Some of the parts are fairly inexpensive, for those who have the patience to shop around. The teenager found a flat-screen monitor for just $20, so he can display the high-energy reaction that he plans to run inside his spherical steel chamber.
He estimates the total cost at more than $1,000, and he has raised enough already. Now comes the rest of the complex assembly process, along with patiently explaining it to those who get the wrong idea.
"The most common reaction is, `Make sure you don't blow up your school. Make sure you don't blow up your house,' " he said.
No danger of that, said physicist Zwicker, who also is a New Jersey state assemblyman.
There are some risks to the person operating the device, but all can be managed with appropriate safety features, he said. At full power, the reactor can emit some neutrons and electromagnetic radiation, so Udotong should protect himself with shielding around the device, for example.
In addition, the device requires a power supply with at least 20,000 volts – readily obtainable on eBay – so it must be carefully grounded. But it draws very little current, so there is no risk to anyone outside the room, and it will not blow the family's electric bill.
The first person to make a fusor was Philo Farnsworth, in the late 1950s, though he is better known as for his pioneering work developing the television a few decades earlier.
Paul Schatzkin, who hosts the fusor website and wrote a Farnsworth biography titled The Boy Who Invented Television, estimated that 50 to 100 people are active on the site at any one time.
Among other young builders are Wayne, N.J., teenagers Scott Moroch and Jack Rosky, who finished their device two summers ago in a lab at the New Jersey Institute of Technology and posted a video online.
Briefly, such devices work like this: vacuum pumps are used to create ultralow pressure inside the fusion chamber, to eliminate stray air molecules that could interfere with the reaction.
Power is then supplied to a mesh of wire inside the chamber, creating an electric field that accelerates hydrogen isotopes and forces them together until they fuse.
Though they yield only small amounts of energy, they look impressive. The charged hydrogen ions take the form of a glowing, purplish plasma, an effect that fusioneers refer to as a "star in a jar."
With all that brotherly brainpower in one family, does Steven Udotong feel pressure to keep up? Mainly, he said, they are supportive.
"They're encouraging me to keep going," the teenage fusor-maker said, "and get it done as soon as possible."