How do you get that? In the UK our nuclear weapons are US bought so we don't use any fissile materials we make, and my understanding was submarine reactors are very different to traditional utility scale reactors, to the point that different companies produce them.
It is all about creating the industrial base with people going through university specializing in it. This is from last time I googled the topic:
In 2017 this angle was up in the news in the UK. Take the responses as you like.
> The government is using the “extremely expensive” Hinkley Point C nuclear power station to cross-subsidise Britain’s nuclear weapon arsenal, according to senior scientists.
> In evidence submitted to the influential public accounts committee (PAC), which is currently investigating the nuclear plant deal, scientists from Sussex University state that the costs of the Trident programme [1] could be “unsupportable” without “an effective subsidy from electricity consumers to military nuclear infrastructure”.
> [...]
> This week, the Green MP Caroline Lucas asked the government about the Ministry of Defence and the business department discussing the “relevance of UK civil nuclear industry skills and supply chains to the maintaining of UK nuclear submarine and wider nuclear weapons capabilities”.
> Harriett Baldwin, the defence procurement minister, answered that “it is fully understood that civil and defence sectors must work together to make sure resource is prioritised appropriately for the protection and prosperity of the United Kingdom”.
> [...]
> At the PAC hearing, the Labour MP Meg Hillier asked whether “Hinkley is a great opportunity to maintain our nuclear skills base”.
> Lovegrove answered: “We are completing the build of the nuclear submarines which carry conventional weaponry. So somehow there is very definitely an opportunity here for the nation to grasp in terms of building up its nuclear skills. I don’t think that’s going to happen by accident. It is going to require concerted government action to make that happen.”
> Andrew Stirling believes that there was a crucial, largely unspoken, reason for the government’s rediscovered passion for nuclear: without a civil nuclear industry, a nation cannot sustain military nuclear capabilities. In other words, no new nuclear power plants would spell the end of Trident. “The only countries in the world that are currently looking at large-scale civil power newbuild programmes are countries that have nuclear submarines, or have an expressed aim of acquiring them,” Stirling told me.
> Building nuclear submarines is a ferociously complicated business. It requires the kind of institutional memory and technical expertise that can easily disappear without practice. This, in theory, is where the civil nuclear industry comes in. If new nuclear power plants are being built, then the skills and capacity required by the military will be maintained. “It looks to be the case that the government is knowingly engineering an environment in which electricity consumers cross-subsidise this branch of military security,” Stirling told me.
