I think these projects are less about making money directly. Mostly these projects are only profitable/feasible with the help of lots of government funding. I assume they have secured some of that.
The reason that the British government is interested in subsidizing nuclear is that they want to maintain their nuclear capability and want to stay credible as a nuclear power. That, and the French are also investing. Either way, that makes it interesting for the likes of Rolls Royce to get involved. There's government money to be had. And maybe Rolls Royce stumbles on something useful; like a cost reduction that makes nuclear a bit less expensive. I wouldn't count on that happening quickly though or in any amounts that really matter.
The reason that the British government is interested in subsidizing nuclear is that they want to maintain their nuclear capability and want to stay credible as a nuclear power. That, and the French are also investing. Either way, that makes it interesting for the likes of Rolls Royce to get involved. There's government money to be had. And maybe Rolls Royce stumbles on something useful; like a cost reduction that makes nuclear a bit less expensive. I wouldn't count on that happening quickly though or in any amounts that really matter.