Fred Starr recollects – Another one bites the dust

Materials World magazine
25 Mar 2019

Looking at the UK’s nuclear power prowess

Great pop songs have titles and lines that capture the moment. Many of us, hearing that Hitachi was abandoning its plans to build nuclear stations at Wylfa, Wales, and Oldbury, England, may have begun to hum, mentally at least, Freddie Mercury’s rock anthem. These two pressurised water reactors (PWR), along with that one at Moorside in Cumbria, makes three cancellations in as many months. The only solid decision
is Hinkley Point C.

This upsets oldsters like me. The decisions not to proceed are not being taken in this country. How, I ask, have we reached this state? The UK once boasted it was the first to produce electricity from nuclear energy. While not involved in the nuclear sector, what went on had a profound effect on my life in British Gas and after I left. As a materials scientist, the high temperature materials issues encountered by the British reactors were of direct interest.

We could have had it all

The line from Adele’s revenge masterpiece, Rolling in the Deep, epitomises how, given the head start we had with our gas-cooled reactors, it seemed that the UK had it made. We had a very rational approach. Gas-cooled reactors were capable of being evolved, temperature-wise. Magnox was just the first step, to be followed by the advanced gas-cooled reactor (AGR) and eventually, the helium-cooled very high temperature reactor (HTR). The AGR, with its high steam temperatures, was much more efficient than the French and American water-cooled reactors, which have no scope for development. The HTR, as well as being an incredibly efficient basis for power generation, had potential for the smelting of metals.

It all went wrong when the phenomenon of breakaway corrosion came out of nowhere, hitting both Magnox and the AGR. Then was the realisation that the graphite moderator was a life-limiting feature. The continual bombardment by neutrons smashes up the graphite lattice, distorting and cracking the bricks. Over the years it became clear that our reactor programme was rolling in the deepest dirt.

Chain reaction

Technological time never stands still and neither does politics. The UK and Continental Europe were once so rich in energy, in the form of coal, they could afford to waste this precious resource. By 1950, coal was said to be running out and nuclear energy was seen as the only viable substitute. The discovery of massive reserves of oil and gas in the North Sea changed all that. Nuclear power, expensive and an environmental hot potato, could be shelved. In the UK, where we had oil and gas coming out of our ears, the opportunity was taken to privatise government-owned industries, which included the nuclear sector.

My Assistant Director, Grev Gibson, realised the implications. Government-backed interest rates for nuclear construction represented a hidden subsidy. He perceived that privatised companies would have to get their money from the banks, paying much more. In this shareholder-driven world, future power plants would be combined cycle gas turbines (CCGT) – running on gas, and quick and cheap to build.

Gibson also saw the proposal I was coming up with, the closed-cycle gas turbine, even better than CCGTs for power generation, as a potential winner for British Gas. Given the go-ahead, the contacts I made with the high-temperature reactor programmes at the National Gas Turbine Establishment at Farnborough and at KFA Juelich in Germany were absolutely vital. From Juelich I learnt the best turbine blade material was molybdenum. Its temperature performance transforms the thermodynamics of the closed cycle.

Things can only get better

Another drawback of the UK’s gas-cooled reactors is their complete inability to adapt output to the demand for power. Fossil power plants have to do this job, sometimes having to be shut down for most of the day. It impacts running costs, reliability and maintenance. Back in 2001, after I left British Gas and joined ETD, I helped to set up an international conference on the subject.

In my own lecture, in the interest of bringing in more work to ETD, I did my best to put the frighteners on to the CCGT people. While nuclear was giving the fossil fuel sector a headache, this would be a breeze compared with wind power, which is essentially unpredictable. It was the coming threat.

It is possible that this conference, and others I was involved with, got the operators and designers of CCGTs to think about what they should do. But only in the past five years have manufacturers begun to offer equipment that is wind ready. Today, the Irish grid will run with up to 60% of the power coming from wind, defying the Jeremiahs who go around saying this is impossible. So, perhaps we don’t need nuclear after all. Music to my ears.