[acsinuk (OP)]

Recently visited Dungeness and found that they have not generated power for over a year although the "B" station is totally intact after cooling down. .
We keep being hassled by the government to buy electric cars assuming the electricity to charge the batteries is produced in a green environmentally way.   But it is not!!
Look at the gridwatch stats     https://www.gridwatch.templar.co.uk/ 
 
   If you compare it with another statistic site we find that they are different?
 
    https://grid.iamkate.com/ 

This sunny windy morning 3 August shows that

         FUEL              GW        %
   Fossil fuels   5.1       19.2
      Renewables   10.0       37.7
     Nuclear/other      6.9        26.3

But this assumes that some of our imported power imported from France is nuclear .possibly 12 GW and UK just 4.7GW. as confirmed by gridwatch        https://www.gridwatch.templar.co.uk/

We need to get our nuclear stations back up and running quickly to green our grid before spending tax monies on motorway charging stations and electrifying transport.

[Origin]

We need to get our nuclear stations back up and running

The problem is the radioactive waste that is produced.  In the US we still don't have anyplace for long term storage.

[paul cotter]

I would prefer to live close to a nuke power plant than a coal burner. I know waste is a problem but surely not intractable. Deep mine storage in ceramic/glass form has been suggested but whether it has ever been implemented I don't know. The reserves of uranium and thorium would power the world for a heck of a long time.

[alancalverd]

The problem with nuclear power is the quantity of fossil fuel you need to burn to build a new nuke. It made economic sense in the 1950s when we had functioning coal mines and before oil became the chosen weapon of Allah, but nowadays the financial payback period is too long to attract investment and the energy breakeven is dubious. If you add the political risk of decommissioning and waste disposal, it probably isn't worth the effort.

Never mind. Fusion power is just 20 years away. In 1955, it was only 5 years away! That's progress.

[paul cotter]

Jam tomorrow, but not today.

[alancalverd]

Plus a Hubble factor!

[acsinuk (OP)]

Nuclear waste could be stored in waterproof containers at the bottom of Atlantic ocean for millions of years without bothering us.
In fact, I did read somewhere that where the continental shelves collide it may be possible to get the waste reabsorbed inside the planetary crust.
We could place the waste problem on the back shelf for now and get on and green the grid immediately by going nuclear!!

[Bored chemist]

Nuclear waste could be stored in waterproof containers at the bottom of Atlantic ocean for millions of years without bothering us.

Over a timescale of a million years, the bottom of the Atlantic is not reliably waterproof.

Dumping at sea is illegal- for a reason.

[alancalverd]

We could place the waste problem on the back shelf for now and get on and green the grid immediately by going nuclear!!

But see reply #3. You have to burn an awful lot of oil to make a nuclear power station, and even if you ignore the carbon footprint, you may not get your money back.

[acsinuk (OP)]

Alan, Nuclear submarines are safe so just build a big one and float it into Dungeness under water and connect up to the grid if we cannot rehab the "B" station economically.
Solar and wind cannot be reliable on for power in cold winter nights and we must green the grid..

[alancalverd]

Nuclear submarines are safe

Actually, no. The radiation dose to the crew and maintenance personnel  would not be acceptable in a permanent civilian unit. And the cost is still prohibitive.

The only sustainable solution is to reduce demand (by reducing the population) and use renewables to generate hydrogen.

[Petrochemicals]

Actually, no. The radiation dose to the crew and maintenance personnel  would not be acceptable in a permanent civilian unit. And the cost is still prohibitive.

Nonsense, if the dose is as much as pilots  get the government would be sued these days.

[alancalverd]

The statutory occupational dose limit is 20 millisievert per year, 20 times the "public" limit. When designing any publicly-accessible facility you need to adopt a dose constraint of about 0.3 mSv/year or less.

Submarine crews and shore maintenance personnel are monitored and rotated to keep their dose "as low as reasonably practicable" given the inevitable exposure associated with their employment, but the reactor shielding for any vehicle is necessarily a compromise between weight and safety, which is why there are no nuclear-powered aircraft. To bring the reactor into a permanent civilian facility you would need to build a whole lot more shielding, which demands concrete and steel, which consume a lot of fossil fuel. On patrol, of course, sea water is a very effective and zero-cost radiation shield when the reactor is running at full steam, so you only need to shield the forward bulkhead (assuming the reactor is at the stern) against maximum flux. You can't run the part-shielded reactor at full chat in a crowded harbor, but you'd need to if it is intended to supply the electricity grid.

Civil aircrew generally receive about 4 mSv/yr but there is some debate over whether this is an employment dose since (a) the source is entirely natural and  uncontrollable and (b) it's still within the range of natural background doses to which some populations are exposed (up to 8 mSv/yr in parts of Cornwall, and a lot more in some other countries)  with no evidence of harm. So we have monitoring programs and advisory crew rotation but so far, no lawsuits.

Nuclear submarines generally work at about 200 MW, which won't make much impact compared with Drax (biomass) or any of the coal, nuclear  or gas stations opened in the last 50 years, which run at 2000 - 4000 MW. You could probably run a big hospital from a submarine.

And rerturning to acsin's plan, why build a submarine anyway? A land-based nuke would be a lot cheaper, though still uneconomic.

[acsinuk (OP)]

Alan,
" 8 mSv/yr in parts of Cornwall, and a lot more in some other countries)  with no evidence of harm. So we have monitoring programs and advisory crew rotation but so far, no lawsuits.".
Exactly correct, the legal requirement is totally OTT and unrealistic. Some people at Chernobyl  stayed on and are still alive at age 90 so what on earth are we stating as a safe limit??

[alancalverd]

There is no safe limit.

The statutory requirement for third party exposure is based on the ALARA principle, with a cutoff based on what is practicably measurable. We can usually detect 1 mSv/yr arising from a controllable source, against the local natural background which tends to be fairly stable. 

It's all subject to ongoing debate. There is evidence that folk who live in a background of high gamma exposure (up to 20 mSv/yr) actually live longer than matched controls at 3 mSv/yr, but where the background is alpha radiation (e.g. Kerala) there seems to be an anomalous incidence of birth defects. So I don't argue with the consensus on this one! 

[Bored chemist]

Exactly correct, the legal requirement is totally OTT and unrealistic.

You didn't understand it, did you?
 "as low as reasonably practicable"  is realistic by definition.

[acsinuk (OP)]

So if it is economically impractical to obtain 1 mSv/yr  limit, then as many normal places like Cornwall already have 3 mSv/yr, then why not standardise on the Himalayan high altitude limit [were some over 100 year olds lived all their lives] of 20 mSv/yr as a practical limit which I assume would simplify nuclear construction enormously.

[alancalverd]

which I assume would simplify nuclear construction enormously.

No!

The simplest model of any sort of radiation is a 1/r² decrease in intensity with distance from the source. Now if we set 20 mSv/yr as the limit at the fence of a nuclear power station, 100 m from the reactor, what is the dose rate at 10 m, where the employees are?

What we do is always to protect the employees first, then decide whether additional protection is needed for everyone else. And the answer is usually no.   Except in the odd case of a partially-shielded reactor on a submarine in dock!

[Petrochemicals]

The simplest model of any sort of radiation is a 1/r² decrease in intensity with distance from the source. Now if we set 20 mSv/yr as the limit at the fence of a nuclear power station, 100 m from the reactor, what is the dose rate at 10 m, where the employees are?

Cumulative effects, if you live in Cornwall, work in the nuclear industry, fly for 10 hours a week, have a CT scan, enjoy Brazil nuts and go skiing and mountain climbing you may well rack up quite a dose.

What we do is always to protect the employees first, then decide whether additional protection is needed for everyone else. And the answer is usually no.   Except in the odd case of a partially-shielded reactor on a submarine in dock!

But you are not going to be standing by a reactor for 12 months of the year, it is the same as an x-ray or visiting the chernoblyl reactor, large dose small duration.

[Petrochemicals]

Recently visited Dungeness and found that they have not generated power for over a year although the "B" station is totally intact after cooling down. .
We keep being hassled by the government to buy electric cars assuming the electricity to charge the batteries is produced in a green environmentally way.   But it is not!!
Look at the gridwatch stats     https://www.gridwatch.templar.co.uk/ 
 
   If you compare it with another statistic site we find that they are different?
 
    https://grid.iamkate.com/ 

This sunny windy morning 3 August shows that

         FUEL              GW        %
   Fossil fuels   5.1       19.2
      Renewables   10.0       37.7
     Nuclear/other      6.9        26.3

But this assumes that some of our imported power imported from France is nuclear .possibly 12 GW and UK just 4.7GW. as confirmed by gridwatch        https://www.gridwatch.templar.co.uk/

We need to get our nuclear stations back up and running quickly to green our grid before spending tax monies on motorway charging stations and electrifying transport.

Answering your point, wind is significantly cheaper in this country, we could  just use wind and make a very substantial reservoir for future years if we install enough, the more you build and operate at any one Tim the cheaper it is. Energy storage is the thing we need to overcome, but the governments are all interested in electric cars, heat pumps and solar.