Interesting to see how that might develop and provide, as you say, the lifeline to aging plants. 

From the perspective of hydrogen producers, would this be a marriage of convenience or would it be one that would actually be optimal from the hydrogen side? 

Nothing can give Nuclear a 2nd life. It has been the most expensive power ever made. One disaster and it becomes an even bigger problem than anyone ever thought. Both Nuclear and Hydrogen have been proven to be losers. 

Actually, it is bonkers. From an economic standpoint, the use of hydrogen makes no sense whether using nuclear reactors or renewable energy.

Curiously, similar hydrogen hype has periodically emerged over the years - kind of like locust hatches. Seems to show up every time Democrats run the country.  In the early part of the century, see US law Energy Act of 2005. Therein, was a major push for nuclear hydrogen production. Never happened because the costs were exorbitant. They still are.

Fundamentally, the laws of physics pour cold water on using electricity to break apart the water molecule into oxygen and hydrogen. Requires a lot of energy, making hydrogen a poor fuel. Then there is the stunningly expensive logistics of transporting and storing the hydrogen. Finally, actually using the hydrogen remains problematic.