Nuclear fusion is a tricky business: the last thing you want is
any of the residual radioactive isotopes leaking out from the
reactor. So how might California's National Ignition Facility
mitigate that possibility? By laser punching. Obviously. The NIF
may begin nuclear fusion later this year, according to the New
Scientist: To kick-start the reaction, the plan is to focus 192
high-power laser beams onto a tiny hollow metal cylinder that
contains a small spherical fuel pellet of deuterium and tritium.
The lasers would heat the cylinder to several million degrees,
encouraging it to emit high-power X-rays into the pellet. The
X-rays would compress the fuel to 1/1000th of its original
volume, raising its temperature and kick-starting a fusion
reaction that spews out helium-4 and neutrons. The hope is that
the reaction would release more energy than was injected into
the system. But that approach increases the possibility of
radiation slough, which has lead some scientists to propose a
"laser punch." This approac