Some forms of electrolysis (especially solid oxide) require heat that they can make themselves - but at the cost of reduced efficiency. If they can get the heat “free” somewhere else - such as near an industrial process or generator that gives off heat, the efficiency of the entire process can approach 100% - hence why they proposing collocating nuclear and electrolysis .

Respectfully, No. it’s matching supply and demand for greener H2. Thanks to steam methane reformation, H2 can be easily produced and packed into ammonia via the Haber-Bosch process for easy transportation. However this process uses methane as the feed stock and therefor a big carbon footprint. Using a strip of nuc power and electrolysis facilitates the same thing with almost no carbon footprint. Furthermore the waste hear from the reactor can improve the efficiency of the conversation.