Not enough tritium to go around
ITER (International Thermonuclear Experimental Reactor) is a project aimed at replicating the fusion processes of the Sun to create energy on the Earth. It’s currently expected to consume most of the world’s supply of tritium to fuel a fusion reaction:
Most fusion scientists shrug off the problem, arguing that future reactors can breed the tritium they need. The high-energy neutrons released in fusion reactions can split lithium into helium and tritium if the reactor wall is lined with the metal. Despite demand for it in electric car batteries, lithium is relatively plentiful.
But there’s a catch: In order to breed tritium you need a working fusion reactor, and there may not be enough tritium to jump-start the first generation of power plants. The world’s only commercial sources are the 19 Canada Deuterium Uranium (CANDU) nuclear reactors, which each produce about 0.5 kilograms a year as a waste product, and half are due to retire this decade. The available tritium stockpile—thought to be about 25 kilograms today—will peak before the end of the decade and begin a steady decline as it is sold off and decays, according to projections in ITER’s 2018 research plan.
OK, but what does this have to do with flashlights?
Many nuclear reactors use ordinary water to cool the core and “moderate” the chain reaction, slowing neutrons so they are more likely to trigger fission. CANDU reactors use heavy water, in which deuterium takes the place of hydrogen, because it absorbs fewer neutrons, leaving more for fission. But occasionally, a deuterium nucleus does capture a neutron and is transformed into tritium.
If too much tritium builds up in the heavy water it can be a radiation hazard, so every so often operators send their heavy water to the utility company Ontario Power Generation (OPG) to be “detritiated.” OPG filters out the tritium and sells off about 100 grams of it a year, mostly as a medical radioisotope and for glow-in-the-dark watch dials and emergency signage.
Ah, so that’s where those trits come from for the Noctigon KR1/KR4 tailcaps. And that’s why they’ve been getting so expensive and hard to get.
Seems like they’re getting ready to get even more pricey.