Yeah, building a 70m diameter device is obviously going to be more expensive than building a 12m diameter device, but assuming the budget is available there's n

Yeah, building a 70m diameter device is obviously going to be more expensive than building a 12m diameter device, but assuming the budget is available there's no technical obstacle to doing so. SNO+ cost about $100 million to build which is a decent bit for a science project but nothing for a military procurement project. Assuming cost scales with volume (which I am skeptical of), 200 times more expensive would be $20 Billion - about 1.5x the cost of a ford class carrier. Is knowing the location of nuclear reactors to that level of precision worth that price tag? I don't know but it's within the range that someone could make a plausible argument for it. If we assume construction takes 10 years, as it did for SNO+, then the project would represent 0.2% of the US's annual budget. And these are directional detectors, they don't need to triangulate. You can most definitely identify the location of a reactor with one detector, which is exactly what this study has done. If you were to go with multiple detectors, they can all get proportionally smaller and thus cheaper, to say nothing of potential economies of scale.