The talk forgot about the limitations of nuclear energy:
The first point is that nuclear is expensive - the example France is flawed as the price is a political both in France and Germany: quite some subsidies to nuclear in France and tax and paying for the early phase PV in Germany. Currently Nuclear is more like 3 times the price for wind, PV or natural gas. This a major reason there is no much new build nuclear.
A 2 nd point is that there is very little capacity to really expand on nuclear. Currently the build capacity is hardly enough to replace those reactors phased out for age reasons. The typical light water reactors need very large forge parts that can essentially only be build in a single plant in Japan. So need to build new steel plants first. So even if many new plants are ordered now get them ready in 2050 - maybe.
With massive use of nuclear, we run out of easy to get uranium. So the uranium mines get considerably larger and dirtier as more and more lower grade ore has to be used. There is enough uranium, but it would get way more expensive, up to the point that the uranium cost would matter if used in conventional reactors. If breeder type reactors are considered the price like goes up and it might take another 30 years to develop.
Nuclear energy is also not flexible - so a little complementary to solar it gives too much power at night. Not using the power at night would about double the price. So like the renewables nuclear needs some kind of storage or other source to compensate the fluctuations.
The high percentage of nuclear in France only works because they also use their neighbors to make up for fluctuations and as a backup.
If taking safety serious nuclear is not even reliable: the usual safety concepts assume that the plants are shut down if a safety issue comes up. One can not do that if one relies to a large part on nuclear power from a single type of reactor. So in the US they did not turn down most of there reactors after the Fukushima accident showed up safety problems with the US BWR reactor design - by the rules they should have, but they had trouble doing it. So they delayed the required safety upgrades.
Nuclear has has much of the costs up front and at the very end. This is a problem with poorer countries: they don't have the money to start with and for the costs to cover disposal and dismantling it would be hard to find a safe way to put aside that money. This also applies for costs for a possible accident - the USSSR did not pay most of the Chernobyl accident cleanup / cover-up
. The cost of a major accident can easily be too much for a smaller country and it can also effect neighboring countries. For the US view, just imagine Cuba building 5 new nuclear pant's (especially Russian type RMBKs, as they don't need the large steel parts) with all it's implications.
Nuclear power also has some connection to nuclear arms - even if not planed so initially the waste could be used in some kind - at least as a dirty bomb.