Regulatory burdens on fission result from the inherent risks and negative externalities. You’re never going to see huge long term exclusion zones with coal, but nuclear has two of them right now (Ed: Overkill though the current size may be) which also have massive government funded cleanup efforts.

So while regulations may be overkill it’s not arbitrary only hydro is really comparable but hydro also stores water and reduces flood risks most years. Fusion sill had real risks, but there’s no concern around $500+ Billion cleanup efforts.

I wonder how bad the property value damage would be from widespread tritium contamination of ground water.

Depends on if anyone uses wells in the area. Probably not that much outside of some sci-fi movie extreme as piping water from in contaminated regions wouldn’t be particularly expensive, but the question is assuming something I’m not sure is possible.

How exactly would you get meaningful widespread tritium contamination of groundwater? IE not just the trace amounts you see from existing nuclear reactors.

Groundwater doesn’t flow quickly from a point source and tritium has a fairly short half-life. 60 years later you might be looking at a larger though still small area, but 97% of the stuff will have decayed and what remains is now diluted and doesn’t bioaccumulate.

It’s not going to concentrate around some site after entering the atmosphere the way heavier than air particulate pollution would.

The flow of tritium through a DT reactor is five orders of magnitude higher than tritium production in a fission reactor of the same thermal output. To put a number on it: the tritium produced and consumed in one year by a 1 GW(e) DT power plant would, if released as tritium oxide, contaminate two months of the average flow of the Mississippi River above the legal limit for drinking water.

Fusion power plants aren’t like nuclear reactors where you keep years worth DT in the reactor. DT only works if you’re actively recycling a breeder blanket. They are also going to be working with gasses as unlike fission reactors it’s not produced in fuel submerged in water thus contaminating the water.

Nearly pure tritium is extremely valuable so we aren’t going to be dealing with some long term leak. You hypothetically might have a large tank with say 1 month of T2 fuel but that would be really expensive directly and waste quite a bit of fuel through nuclear decay over time. Having that much fuel across multiple different systems is more plausible but then requires a wide range of different failures. But let’s assume such an improbable tank catastrophically fails, outside of containment, and then completely burns so the tritium will eventually fall back to earth.

It then has to rain over land, though even then storms don’t release all the moisture in the air, that water must be absorbed into the soil rather than running off or evaporating, where it’s further mixed with groundwater as it slowly seeps deep enough to be collected in some well. Thus even if conditions are perfect you’d have trouble reaching above the legal limit for drinking water.

I mean maybe if you intentionally selected the perfect moment with the perfect weather pattern and the perfect local geography and geology perhaps you’d be over the legal limits for a few wells for a little while until it rapidly decays.

My point is: even small leaks (in percentage terms) will result in much larger releases from LWRs. And tritium promises to be very difficult to contain, as it diffuses through a wide variety of materials. For example, it diffuses through polymer seals. Materials of a reactor will become saturated with it, providing a substantial source term in accidents.

Lurking over all this is the issue that loss of property value doesn't require anyone to actually prove tangible harm. The mere fact that property values were affected is enough for a tort.

The kind of releases you’re talking about is 8+ orders of magnitude smaller than in your prior example and again without burning it’s lighter than air and just going strait up. Right now T2 is ~$30,000 / gram hell even D is ~13,000x as much as hydrogen. This just isn’t the kind of thing you’d let escape in meaningful quantities in day to day operations.

When people talk about how safe fusion is they aren’t kidding, even breathing in a significant amount of T2 isn’t particularly dangerous radiologically as density is really low and you will quickly exhale it. Huge quantities would be a larger suffocation risks but then you’re talking multi million dollar accidents simply from lost fuel.