Aside from the Thorp reprocessing plant, which has in fact processed only a modest amount of spent fuel since its commissioning in the mid 90s, the only activity taking place at Sellafield these days is decommissioning. Sellafield's responsibilities are now limited to taking apart old buildings.
There is plenty of work to be done here. It will keep thousands of well paid consultants, contractors and safety case managers busy for the rest of their lives.
For this reason, the company is not particularly interested in new nuclear build. The Sellafield site is unlikely to play any role in a nuclear renaissance. The company plays no part in new reactor design or construction. A few of the nuclear engineers who were originally involved in the UK Advanced Gas Reactor programme can still be found scattered amongst the various consultancies that carry out work for Sellafield and other sites. Most of them are close to retirement age.
If the [political party] chairman is interested in nuclear new build, he would probably do better talking to Rolls Royce Naval Marine, who construct naval pressurised water reactors for the UK's nuclear submarine fleet. This is the only UK company that is constructing reactors right now.
Sellafield is popularly believed - for example, by that chairman - to produce electricity, but looks more like a gravy train to supply money for various types of expert. In a similar way to 'foreign aid' which somehow always manages to disappear with little benefit to the supposed recipients.
The submarine issue is somewhat irrelevant to power supplies for an entire country - the power is far too small-scale - but 'cactusneedles' has a theory to explain what 'nuclear submarines' and other supposed nuclear vessels really are.