Fracking in Lancashire

[cjmillsnun]

You won't get an accident where firefighters outside the building are tripping up on bits of reactor core graphite though.
Even worst case in a more modern reactor will keep the vast majority of the fission products, and the rest of the core, inside the building.

Also note that a positive void coefficient does not necessarily make a reactor unsafe by itself - see CANDUs for example.

CANDUs have their own issue. In a control blackout once the heavy water boils away (the heavy water is the last line of defence in cooling as well as the moderator for the chain reaction), even though a chain reaction is impossible as the moderator has gone the core is uncovered, and you have a meltdown.

That said I still think the CANDU is the best and safest reactor design.

Agree on the containment in western reactors it is far superior to any RBMK reactor.

However there is always the slim chance that a beyond design parameter accident will have severe consequences. They considered earthquakes and tsunamis when they designed the various reactors at Fukushima Daichi. But the tsunami was greater than the event they designed it for and the electrical systems and backup generators were swamped.

I read an interesting book on Fukushima that makes you think. The publishers (the union of concerned scientists) are not anti nuclear power. They want improvements in design.

 

[Bevan Price]

Fracking - I think it is probably safe in some areas where the sub-surface geology is suitable. I would not be happy if they allowed fracking in former mining areas, where there are probably thousands of poorly characterised sub-surface disused mines. I fear that fracking could cause some old mineshafts to collapse and damage surface property.

I also think that Governments are hypocrits when they preach about local democracy - and then overrule local decisions that they consider inconvenient.

As for alternative energy sources, I had hoped that wave power would have become the favoured method by now, supplemented by nuclear power. Solar panels provide a useful supplement, but I do not like land-based wind farms. The most windy areas are often the most scenic, and I don't want to see such areas transformed into unsightly industrial landscapes, probably accompanied by miles of unsightly pylons. (And remember, that would also tend to blight the tourist/leisure industry.)

Tidal power also has problems, e.g. the Severn Estuary provides a home & feeding place for many thousands of birds and other wildlife, which we also need to retain a balanced environment.

 

[HSTEd]

CANDUs have their own issue. In a control blackout once the heavy water boils away (the heavy water is the last line of defence in cooling as well as the moderator for the chain reaction), even though a chain reaction is impossible as the moderator has gone the core is uncovered, and you have a meltdown.

That said I still think the CANDU is the best and safest reactor design.
.

Interestingly the newest CANDU generation [the ones being proposed for MOX fuel burnoff at Sellafield and for the new plant in Argentina, Atucha III] are actually designed so that light water can be dumped into the calandria in such an accident to keep the core covered.
That totally ruins your moderator supply though - but at that point it is either that or lose the entire plant.

 

[J-2739]

To me nuclear is the best way to provide assured, long-term background energy of that kind.

I agree also. Nuclear power is also clean, all you have to do is see where Japan and France are ranked on lists based on pollution to prove this. Only problem is disposal of waste.

Has anyone ever thought of biomass energy as a long term solution? There is a cheap, continuous supply out there.

 

[HSTEd]

There just isn't enough to go around - someone calculated that if half the UK's land surface was devoted to biomass it would produce about enough to support half of the UK's current steel production and nothing else. At best it might be able to cover some chemical feedstock purposes

 

[cjmillsnun]

Interestingly the newest CANDU generation [the ones being proposed for MOX fuel burnoff at Sellafield and for the new plant in Argentina, Atucha III] are actually designed so that light water can be dumped into the calandria in such an accident to keep the core covered.
That totally ruins your moderator supply though - but at that point it is either that or lose the entire plant.

No good in a total station blackout. No power means no way to pump water in. That was the problem with Fukushima.

If you have power with a CANDU you can pump water through the normal and emergency core cooling systems. Therefore no need to get rid of the heavy water.
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There just isn't enough to go around - someone calculated that if half the UK's land surface was devoted to biomass it would produce about enough to support half of the UK's current steel production and nothing else. At best it might be able to cover some chemical feedstock purposes

They reckon that biomethane on its own to its full potential could supply about 1/4 of outer gas need. You'd still need to find the other 3/4 and any additional for any new load that comes on. Plus any additional load for electricity.

 

[HSTEd]

No good in a total station blackout. No power means no way to pump water in. That was the problem with Fukushima.

If you have power with a CANDU you can pump water through the normal and emergency core cooling systems. Therefore no need to get rid of the heavy water.

Its like the ESBWR, its a seismically hardened tank that drains into the Calandria/Vault tank via gravity when powered hold-close valves open [as they would in a station blackout]

 

[Harbornite]

I agree also. Nuclear power is also clean, all you have to do is see where Japan and France are ranked on lists based on pollution to prove this. Only problem is disposal of waste.

Has anyone ever thought of biomass energy as a long term solution? There is a cheap, continuous supply out there.

Another issue with biomass is the pollution generated by shipping it over from the USA.

 

[furnessvale]

Another issue with biomass is the pollution generated by shipping it over from the USA.

Good business for railfreight though!

The nuclear industry is no lover of railfreight, choosing only to use rail when it really has no other choice. Virtually the only traffic being spent fuel in containers which is extremely heavy so rail is the only option. Even then, the spent fuel from Chapelcross was sent by road, being sneaked through the centre of Carlisle at 3am on huge transporters.

 

[HSTEd]

Well to be fair almost nothing you move to and from a nuclear power station is really heavy enough to justify rail operation - apart from potentially spent fuel.

Nuclear very rarely requires loads greater than one lorryload.

 

[TheEdge]

Well to be fair almost nothing you move to and from a nuclear power station is really heavy enough to justify rail operation - apart from potentially spent fuel.

Its not the volume or weight its just the fact its a damn sight safer to move that material by road rather than rail.

 

[HSTEd]

Its not the volume or weight its just the fact its a damn sight safer to move that material by road rather than rail.

Statistically I doubt that conclusion - it seems likely that lorries have more accidents per tonne mile than trains do.

And I am not entirely sure what reason would be used for normal fresh fuel to be treated as dangerous cargo - it isn't very hazardous.

 

[Lankyline]

Essentially 'fresh' nuclear material moves by road for security reasons, material for reprocessing arrives via ship from overseas contracts e.g. Barrow docks and is then generally moved by rail / road, whilst U.K. Plants tend to move material by rail

 

[HSTEd]

Essentially 'fresh' nuclear material moves by road for security reasons,

Fresh nuclear fuel shipments have never been particularly secure - after all there was that incident when a man drove up to the loading dock at Bradwell and absconded with several fresh fuel elements, which he wished to sell to a non ferrous metal dealer.

The real reason is that when you do not require the shielding used for spent fuel [as fresh Uranium Oxide fuels are not significantly active] then there is little reason that rail might be more economic than simply using a lorry.