Chapter Text
So what is that power source, anyway?
Grace has a power source implanted in her abdomen that charges all of her electrical augmentations: it’s a relatively small but powerful energy storage device that, when damaged in the final scenes of the movie, produces an electromagnetic pulse intense enough to fry a Terminator. Despite what’s in the script, however, it is almost certainly not a “thorium micro-reactor” as described.
Regardless of what you may have heard from b-movies through the years, a nuclear reactor is essentially just a high-tech way of boiling water. The heat generated by the reaction of a given nuclear fuel source is used to boil water, which creates steam, which rotates turbines that then create electricity. Future shit or not, a miniaturized steam engine is unlikely to fit inside a human body – what’s far more probable is that Grace’s electrical components are powered by an atomic battery instead.
There are several forms of atomic batteries that actually exist in real life, and some have been in operation for more than half a century. Unlike a nuclear reactor, the heat given off by the radioactive source in an atomic battery is converted directly into electricity by a device called a thermopile (a stack of thermocouples, which convert thermal energy into electricity using the Seebeck effect, which in turn is based on the temperature difference between two different types of metals or semiconductors inducing an electrical current between one another). Plutonium-powered pacemakers were developed and successfully installed in humans in the 1970s to great success, as the long life of the tiny amount of radioactive material meant that cardiac patients wouldn’t have to undergo surgery to get their batteries replaced every few years and the devices would last them the rest of their lives – plutonium-238 has a half-life of approximately 85 years, which is more than enough to support a regular human lifespan. Unfortunately, thorium is not a great material to use for this kind of device – it’s not fissile on its own, meaning it needs a separate (radioactive) neutron source to start any kind of reaction. Despite extensive research, I haven’t been able to find any feasible designs for thorium-based batteries, though I did find a lot of dismissive comments about the concept on various forums full of people asking about the same thing.
Another kind of radiation-powered device known as a betavoltaic cell converts high-energy beta particles emitted from the decay of radioactive isotopes directly into electricity through some physics that are above my pay grade, rather than simply using heat – tritium (a radioactive isotope of hydrogen) and nickel-63 are both popular source materials in this technology. Betavoltaic cells are especially promising as a new kind of power source – in 2018, a team of Russian researchers developed a small nickel-based betavoltaic device that contains ten times the amount of energy as a similarly-sized electrochemical battery. It’s an exciting bit of engineering that I’d love to see more science fiction play around with, and is my personal favorite choice for Grace’s power source in the movie – some sort of very powerful betavoltaic cell powered by tritium would be body-safe and energy-dense enough for her augmentations for sure.
A more unusual non-radioactive option is an emerging branch of technology known as spintronics – essentially magnetic batteries that are charged by passing a series of nano-magnets through a strong magnetic field to “wind them up” like a toy car and induce an electromotive force. Further details are once again above my pay grade, but this technology is expected to be useful for building more efficient solid-state hard drives – maybe useful for some murderous machines in our narrative, and possibly a technology that’s then re-appropriated by the Resistance? These could certainly produce an electromagnetic pulse – more on that in a bit.
Okay, so how did they do that to her?
In the context of the Terminator franchise, much of the technology used by the resistance is pirated and reverse-engineered from the Terminators themselves. Nuclear batteries would be a convenient family of power sources for machines that don’t have to worry about the long-term effects of radiation: they’re stable, very long-lasting, and have the useful side effects of poisoning humans who blow them up. Grace’s power source is likely modified Terminator technology, which in turn likely originated from cutting-edge military tech developed for human use sometime in the 2020s.
I’ve taken a look at Grace’s X-rays and they’re an incomprehensible jumble of metal (which we are also ignoring for the sake of functionality – more on that in a later section) so it’s difficult to see where the reactor is actually installed in her body. It seems like there may be some sort of support structure attached to her ribs that could hold the reactor more or less in place, but it’s anyone’s guess – we can chalk that utterly bizarre X-ray from the ICE facility up to the metallic subdermal mesh plus all her metal bits putting out a weird image and just disregard it because it makes absolutely zero sense. The device is likely tucked into her abdomen roughly behind her stomach and between her kidneys, not especially likely to irradiate her or anyone else if left undamaged, and really not designed to be taken back out again.
This device’s ability to be used as an improvised EMP weapon capable of stopping the Rev-9 is a key plot point, to my eternal frustration. Electromagnetic pulses, much like nuclear tech, are also poorly understood and badly portrayed in science fiction. EMPs can take many forms – lightning strikes are a perfect example of a type we all encounter on the regular! The power surge from shoving the power source into the Rev-9’s eye socket was enough to short-circuit it for good, passing a powerful enough current through its skeleton to fry and partially melt it. It was not whatever nuclear material that was in her battery that was the lethal component, it was the electric and magnetic currents it produced on contact with the Rev-9’s metal body – which means there were likely other ways of defeating the machine had they gotten to a different location. Some options might include:
- Trapping it in an induction furnace at a foundry and letting the magnetic current melt it.
- Electrocuting it with a power line or having some final showdown at a substation and just using high voltage to fry it.
- Sticking it in an MRI?? Good luck.
What does this all mean for the story?
Grace’s power source was sort of an irradiated Chekov’s gun in Terminator: Dark Fate – as soon as we saw that the EMP weapons from Sarah’s military contact were damaged, I had a grim idea of where the movie was going with a cyborg who had something radioactive implanted in her body. However, we’re really all here for the “Grace lives” AUs. You can go several ways with this: 1) leave her power source alone and have her survive the end of the movie because she’s not dealing with massive abdominal trauma, 2) have her lose the power source but not immediately die and find a clever narrative way to save her: she does not necessarily need the power source itself to survive.
Grace’s power source operates her electrical augmentations, not the organic parts of her body. She’d still have a bunch of metal implanted in her but would no longer be able to use her heads-up display enhancing her vision, her enhanced hearing, and her super-fast reflexes, as those are all controlled by electronic components that interface with her nervous system. This would likely result in some neurological impairment (the severity of which could fluctuate depending on your narrative needs) and relatively limited senses compared to what she’s gotten used to from her augmentations. Her metabolism, healing ability, and reinforced bones would be unaffected, and her major organ systems don’t run on the power source and so should be unaffected by its removal if she somehow survives the encounter at the dam and gets immediate medical treatment – it’s a stretch, but what is fanfiction for if not creative liberties in who gets to have a happy ending after all. (See the upcoming section on Grace’s ongoing medical needs for further details.)
A final note: “But the thorium micro-reactor is canon! Grace described it out loud!” To that I have two responses:
1) it’s much more likely that Grace’s power source was manufactured with energy provided from a thorium micro-reactor – research on thorium reactors has been ongoing for decades, and while they make for a poor medical device, they could provide a reliable, lower-maintenance, and relatively safe source of power for Resistance bases in a badly ecologically-damaged world, especially since thorium can be used in breeder reactors to ensure a steady fuel supply long-term.
2) Grace’s quip about Future!Dani having her tattoo the coordinates on her body “as if I couldn’t remember shit” becomes both funnier and sadder if you consider she’s just gone through some massive, traumatic bodily changes in the middle of an all-out war for the survival of the human species and might have misremembered a technical detail – she’s had to memorize a lot more immediately relevant information that’s not related to the finer points of nuclear engineering. I’ll give her a pass on this one.
In summary:
- Grace’s power source is most likely an atomic or magnetic battery or a betavoltaic cell; not a ~thorium micro-reactor~.
- Ignore that X-ray in the movie, it won’t tell you anything useful about where or how the device is placed in her body.
- There’s lots of ways to create or attract an EMP that don’t involve vivisecting our cyborg hero.
- If her power source is left alone, she could absolutely live a full and relatively healthy life – she’s not slowly being irradiated or anything like that; it would be very bad design.
- Even if her power source was removed, she doesn’t necessarily need it to survive – just to power her augments. She’ll have some lasting nerve damage and other physiological consequences, but she could very well pull through.
- Seriously, disregard both the thorium and the micro-reactor bit. Poor Grace has enough on her plate and genuinely can’t be expected to remember all this nuclear nonsense so long as it’s doing its job of keeping her alive.