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Germany shutting down last nuclear power plants on April 15th
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james_s:

--- Quote from: rf-messkopf on April 11, 2023, 10:09:59 am ---After a four or five years when the spent fuel assemblies are transferred to dry storage, this is just a couple of kilowatts, i.e., not worthwhile. For example, this storage cask is rated for a maximum of 39 kW total heat load.

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That's over 130k BTU/h in heat, enough to heat several average homes. It's a shame that heat can't be harvested for heating things.
daqq:

--- Quote from: james_s on April 11, 2023, 09:16:18 pm ---
--- Quote from: rf-messkopf on April 11, 2023, 10:09:59 am ---After a four or five years when the spent fuel assemblies are transferred to dry storage, this is just a couple of kilowatts, i.e., not worthwhile. For example, this storage cask is rated for a maximum of 39 kW total heat load.

--- End quote ---

That's over 130k BTU/h in heat, enough to heat several average homes. It's a shame that heat can't be harvested for heating things.

--- End quote ---
It probably could, but in the grand scheme of things it's very small and moving a really huge and weighty cylinder that requires special handling somewhere to the middle of a city where such heat might best be used would probably cost more than the heating bill for a whole village. And your local scrap "collectors" would be just too tempted and since they can't read anyway...
Funnily enough there are RTGs ( https://en.wikipedia.org/wiki/Radioisotope_thermoelectric_generator ) - generators that harness decay heat and convert it into useful power. Mind you, they are in really special applications. And it's not decay heat of random spent fuel rods but of specific isotopes specially chosen.
Neutrion:

--- Quote from: Kleinstein on April 11, 2023, 07:18:47 pm ---
--- Quote from: Neutrion on April 11, 2023, 03:52:10 pm ---And how much outage would mean the refuelling? If the aim is to make it work for another 1-2 years?  Would the costs, risk or time to do it enormus?

And what if that decision had been made immediately after the government got the results of the studies regarding the possible enlenghtening of the usage of the plants?

If there would be a political will, could it be made economically feasible in a timeframe and for costs that would beat power to gas initiatives (or maybe renewables)during the same time period?

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Refueling for 1-2 years would not make much sense. Usually the fuel is in the reactor for some 3-4 years with exchanging something like 1/3 every 12-18 months or so. So if they would order new fuel it would be more like for 3-4 years at least - ideally longer to have a mix of old and new rods as the reactors are planed to work with. They may keep a little of the old fuel, but likely not much as the really run it to the end with not much juice left. The unusual fuel mix may need extra certification.

The other point is that the reactors are over-due for a major revision / inspection. They are currently running on extensions/exceptions from the normal rules. So not just the normal short outage to change the fuel, but more like 6 months or langer to check and replace parts that wear-out and upgrade to current standards where needed. A point here is that the replacement parts are no longer planed for and possibly even the machines / molds to make them may no longer be availabe, as they did not plan to ever do this revision anymore. Chances are the mechanics origianlly trained for this job also have a new job. With short notice the revision would likely take longer than normal. So the time (1-2 years) to order an manufacture new fuel may not even be the limiting factor. With the extra effort if would likely not make much sense to restart for only 1 fuel load.

The unlikely scenario to extend the plant life would be some 1-3 years to get them ready for a restart and than maybe 6-10 years, or what ever is left of the planed 40 years of design life. A much shorter time may not be worth the effort.
I don't see a political will for such a longer term commitment and all the regulatory effort for only 3 reactors.

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So to sum it up:
It is technically not feasible to run them for an extra 1-2 year, but would be possible to run them for a longer term.
You mention the posibble issue regarding the aviability of some tools etc., but I suppose the studies which were made during last summer were there exactly to ansver that question. Possibly also the costs. Are they publicly aviable?
So in this case because the coal phase-out is planned to 2030, there could be still a useful 3-4 years until subtitution by renewables. (Or the French. (Or to fulfill AP new-speak guidelines "people experiencing frenchness"))
In that case we still don't know whether the population really supports coal instead of nuclear for a few extra years, so this decision can not be blamed on democracy as this scenario was not included in any parties program before the war, and the greens are in clear minority by the number of voters.
Are the coal plants be there to run only in emergency situations, or will they take over the whole base load 4 GW? continuously?
Siwastaja:

--- Quote from: langwadt on April 11, 2023, 06:21:41 pm ---
--- Quote from: Siwastaja on April 11, 2023, 04:06:15 pm ---These plants are designed to operate safely for much more than half a century. It's not that extending the operational life by "a few years" is any problem. It's extension after extension after extension after extension which gradually becomes a problem. AFAIK, this practice is being critiqued in the USA.

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but if checks, maintenance, etc. have been planned to the deadline and personnel already moved on I suspect it is not a quick or small task to do

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Of course it isn't. You would pay for the political mistake of early shutdown of all nuclear, and no, you would not extend by just 1-2 years, realistically the problem isn't also going away in just 1-2 years. You would commit to 5-10 years of extension, and hope we have solved the issues with renewables by then. And don't get me wrong, the track record with renewables is not that bad. It's getting there. Struggling was and is to be expected.

Now if politicians could commit to say 10 years, then re-recruiting the staff, getting new fuel etc. makes a lot more sense than for 1-2 years. The cost is still higher than what it would have been if the replacement planning was done more carefully to begin with, but that's the price you need to pay.

A large bill has been paid anyway. Finnish taxpayers subsidized Russian's natural gas by over 10 billion € through German gas customers. But because Finland is now basically bankrupt, Germans need to start paying their own energy bills (like we have always done).
vad:

--- Quote from: Siwastaja on April 12, 2023, 02:29:11 pm ---You would commit to 5-10 years of extension, and hope we have solved the issues with renewables by then.

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Nuclear power plants operate as baseload plants and as load-following power plants. Renewable sources are intermittent and weather- and time-of-day dependent. They are not a replacement for nuclear power.

Shutting down NPPs would either lead to more power generation from coal and natural gas, or result in blackouts.
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