Sounds like the goal of the test wasn’t to vet ignition power in relation to output. These people are testing the durability of system designs that can maintain a reaction after ignition.
If this was a car, they wouldn’t be testing the fuel efficiency, they’d be testing how long they could drive before the wheels fell off.
sushibowl@feddit.nl 2 months ago
No magnetic confinement fusion reactor in existence has ever generated a positive output. The current record belongs to JET, with a Q factor of 0.67. This record was set in 1997.
The biggest reason we haven’t had a record break for a long time is money. The most favourable reaction for fusion is generally a D-T (Deuterium-Tritium) reaction. However, Tritium is incredibly expensive. So, most reactors run the much cheaper D-D reaction, which generates lower output. This is okay because current research reactors are mostly doing research on specific components of an eventual commercial reactor, and are not aiming for highest possible power output.
The main purpose of WEST is to do research on diverter components for ITER. ITER itself is expected to reach Q ≥ 10, but won’t have any energy harvesting components. The goal is to add that to its successor, DEMO.
Inertial confinement fusion (using lasers) has produced higher records, but they generally exclude the energy used to produce the laser from the calculation. NIF has generated 3.15MJ of fusion output by delivering 2.05MJ of energy to it with a laser, nominally a Q = 1.54. however, creating the laser that delivered the power took about 300MJ.
DataDisrupter@feddit.nl 2 months ago
I wasn’t aware of that distinction about the energy for the laser to generate the heat energy within the reaction not being factored into the Q value, very interesting, thank you! Would that energy for the laser still be required in a “stable reaction” continuously, or would it be something that would “trail off”?
Womble@lemmy.world 2 months ago
Inertial confinement doesnt produce a “stable reaction” it is pulsed by it’s nature, think of it in the same way as a single cylinder internal combustion engine, persiodic explosions which are harnessed to do useful work. So no the laser energy is required every single time to detonate the fuel pellet.
NIF isnt really interested in fusion for power production, it’s a weapons research facility that occasionally puts out puff pieces to pretend it has civilian applications.
frayedpickles@lemmy.cafe 2 months ago
Your take is incorrect.
Lycist@lemmy.world 2 months ago
theguardian.com/…/us-scientists-achieve-net-energ…
I’ve seen a few mentions of positive output.
frayedpickles@lemmy.cafe 2 months ago
The input energy doesnt matter that much. Nobody is going to use 1980s laser tech to power a real reactor. As with OP, inertial confinement is interested in very small nuanced science aspects, not making a power plant.