SMR's a conundrum.

A Scram is an emergency shut down of a reactor, usually by inserting the control rods. Nothing to do with the Windscale incident where the graphite moderator caught fire due to a release of Wigner energy. This doesn't make it any less significant, but such things are much better understood nowadays. The Chernobyl design reactor would never have got past the regulator in this country, and it was deliberately operated in an unsafe manner with safety systems overridden.

We have a stark choice, extreme weather making large areas of planet uninhabitable, no power when the wind isn't blowing, or reliable, safe nuclear. I know which I prefer.

Sad after all the years since Calder Hall, we still haven't got a SAFE steam kettle and given the speed of invention in the event of a war, we can devise more effective ways to kill each other quickly but it's so expensive to "Research" ways to have a more comfortable existence without screwing the planet.

Regards Ian.

DW I was thinking of the 'Super scram lethal dump/injection of Lithium '.

I see the 'nukes' were running IN the red at 6.15GW this morning , flat out and some more.

This will not end well.

Not necessarily, if that was from Gridwatch. It may well mean that all the units are available and on-line. Nuclear power does require reloading with fuel, which is generally a sequence of down time, to best suit the grid and the generator, and normally carried out before the winter demands are upon us.

Nuclear plants are designed to run at full capacity and they are less efficient if throttled back - hence why they are base load generators.

Edited By not done it yet on 11/11/2021 14:26:41

Coal also runs most efficiently flat out: high thermal lag in the boilers mean they respond slowly to increased demand, and waste a lot of energy when throttled back.

Gas is the best generator of all in terms of efficiency and flexibility. A gas turbine fires up from cold in a few minutes, and they can be turned off without wasting fuel. It's possible to produce electricity with banks of medium-sized generators that come on and off-line individually as necessary to meet demand, as well as operating more sluggish combined cycle plants that achieve extremely high efficiencies. Burning gas produces less Carbon Dioxide too. The 'Dash for Gas' occurred because gas is cheaper, cleaner, more efficient and more flexible than coal. Not just thermally, but gas power stations were smaller, cheaper and faster to build than coal.

Despite gas having many advantages, time and circumstances have shifted against it in the UK. Gas made huge sense when the North Sea produced it in large quantities. Far less gas coming out of UK North Sea sources today, so most UK gas is imported. Getting expensive and some of the suppliers are unreliable. Green is cheaper: if only it was consistent as well!

I don't think there's a single simple solution to energy supply in future. Instead, many different sources will have to be managed together as a basket. Management isn't so much about running technology, it will be more about continually balancing demand, supply and costs, as they change hour by hour. There will have to be a charge for pollution.

Dave

Just look at the gas generation and the interconnector graphs 0600---1200hrs today , there was a problem !

To pose an idiot question.

If when decommissioning a nuclear power station, the materials are still so radio active when "exhausted", as to be dangerous, there would seem to be energy still be obtained. Hopefully, it would be possible to extract more energy, from the fuel, until it would be so depleted that it no longer represents a danger, or at most, a greatly reduced danger.

Ultimately, one would hope that the uranium could be reduced to lead, which is, by comparison, fairly harmless?

Howard

Still not relevant to the Windscale fire, this was a graphite fire, eventually put out with a fire hose.

To get more use from spent fuel you have to reprocess it, extracting the radioactive fission products from the (now depleted) uranium and plutonium. Unless you have a fast breeder reactor programme to convert depleted uranium into plutonium, from which you then make more fuel, it is my opinion that the best thing to do with spent fuel is store it in a retrievable form until the relatively short lived highly active parts have decayed, and then either permanently dispose or recycle. We have lots of plutonium in store, it was intended to build a reactor at Sellafield to use plut fuel to get rid of it. Note the plut from spent commercial fuel is not much use for making nuclear bombs, and as plut is an alpha emitter it is quite easy to store safely.

Edited By duncan webster on 11/11/2021 18:29:38

A small point on reactor refuelling:

Pressurised Water Reactors are refuelled off load. This can be done during statutory examinations or refits.

The last four Advanced Gas-cooled Reactors were intended to be refuelled ON load and this has been done, one channel at a time, although at reduced load, not full load. The wind down/exchange/reload cycle costs lost output. Some feel that it is more cost effective to come off load when demand will below for a period and do a batch. One complication is that because they were intended to be refuelled one channel at a time, storage for discharged fuel stringers is less the 25% of a reactor's complement. (Unless they have increased it since commissioning)