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[Did67]

Indeed.

But the tankers sell well 1 liter of fuel for 1 l, without never displaying the gray energy devoted to prospecting, extraction, transport, refining ...

In energy diagnoses, 1 l of FOD is counted as 1 liter ...

I am not in favor of nuclear energy, even though I still use too much for my taste. I do not want to defend EdF specifically. I just notice that it is not better for tankers.

[I have some cons - rather general - at one of my producers of pellets!]

PS: but I think we have already drowned our friend!

[I Citro]

Yes, for petroleum, we never mention the embodied energy contained in a liter of fuel obtained "at the pump".

While it is common to read that each kWh produced by EDF required 2.58 kWh for its production and transport to your power socket ...

When I mentioned the impact of nuclear energy on global warming, I first thought of the enormous amount of heat dissipated by the cooling systems of the power plants, and then by the gray energy required for the production of nuclear fuel. .

It is more and more frequent to have to stop slices, even entire units in the summer, because the level of the rivers is insufficient to ensure this cooling ...

[Macro]

For the oil it would be in 33% only in 2013 ..Ca surprise me But as it is a product with high energy density whose mastery extraction and transformation for a long time ...

And again the resource is rarefied ... In 1930 it was only 1%

Source a report that sees the energy transistion only by the use of the nucleaire..So the sworn enemas of the petrol ...

[Did67]

This would join this 1 l for 3 which also trailed in my memory.

It must be seen that as for nuclear power, there are certainly monstrous energy "investments": platforms, helicopters, tankers, refineries, etc ... But it must be seen that the volumes processed are then gigantic! In the end, the ratio remains bearable (even if it deteriorates, compared to artesian wells, which flowed by themselves and which were drilled with a small motor!)

[Did67]

When I mentioned the impact of nuclear energy on global warming, I first thought of the enormous amount of heat dissipated by the cooling systems of power plants ...

Even though it sounds huge, it's peanuts in the cycles of nature!

A big cumulonimbus sucks on average up to 700 000 tons of air per second! It can condense about 7600 tons of water vapor. This condensation releases energy ... 19 million megawatts!

Other source:

Cumulonimbus, a characteristic cloud of stormy phenomena, is a real thermodynamic plant, which feeds on hot, moist air to provide the energy needed for upward movements. Its energy is considerable: every second, a large cumulonimbus can suck 700 000 tons of air and thus absorb 8 800 tons of water vapor. The same cloud can return 4 000 tons of water, in the form of liquid water, snow, or hail, to the Earth's surface.

It is indeed a single big cumulonimbus ... So count all, a stormy evening on France!

Or another reflection: all the energy "consumed" by a city like Paris (electricity, fuel, energy of living beings - our food - ultimately dissipates in ... the atmosphere. It is I do not know how many plants nuclear!

I sincerely believe that you are on the wrong track. Not that it does not exist, of course. But that does not weigh in the global energy balance of the planet earth. No more than a peanut or a crumb. Unlike CO² that traps solar radiation over the entire surface of the globe - finally always a half (very exactly, it is the return of the received radiation towards the space which is braked)

[I Citro]

I want to admit that this may represent a trifle compared to a city like Paris ...

I think that even if it seems negligible on a global scale, it contributes to the problem of global warming, as supporters of the throbbing butterfly theory that trigger climate disasters at the other end of the planet.

But I humbly admit that my knowledge is insufficient to argue it.

[Yamatai]

Thank you all for your welcome

I am not aware of stasi at EDF and I think you would be surprised by the number of people who are not pro nuclear in a plant.
Which does not mean that these same people are anti-nuclear.

If we start looking at the heat generated by the air cooler or direct cooling in the watercourse (nuclear or thermal flame) we will have also looked at the heat released by the men, the loss of our homes means of transport, l farming without fermentation gases.

Average instantaneous power (the big mesh)

40GWe over the year = 80 GW (cooling)
66 M of French = 6,6 GW
7,7 M of cows and 14,8 M of pigs = 10,6 GW
Oil consumption 3634 kg / year per person (Re = 30%) = 223 GW
28 M housing at 91 m² on average and 50 kW / h / year = 14,5 GW

Average energy received during a year by 1 km² of a surface covered with water (1,4kw of power over 1300 hours)
0,1 GW
80 GW represents the equivalent of 800 km² of water in natural irradiation in our latitudes. I took because it is the body with the strongest albedo in proportion with about 0,95 in emissivity. I do not know the emissivity of plants in general.

This is not an exhaustive calculation but hey it gives orders of magnitude.

For the Scuds no worries I'm not likely and if I'm here it's not for propaganda

As for the drycooler in France there is if I am not mistaken 34 reactors on 58 who are provided.
After they are not identical to each other. So I guess that depending on the body of exchange and the air flow for refrigeration the volume of water vapor create is different.

The site on which I work is on average 0,5m3 / s evaporated by reactor for a refrigerant flow of 36 m3 / s.
It is more in summer with the temperature effect and the vacuum at the condenser less good, and conversely in winter.

[I Citro]

It's a pleasure to read you.

Thank you for this detailed and informative info.
I hope it is not too confidential to disclose this data on the Chinon plant ...

If I have time, I will ask you for more details about your figures, including these:

28 M housing at 91 m² on average and 50 kW / h / year = 14,5 GW

This seems to integrate uninhabited housing or second homes, because I find this figure quite low.

[Obamot]

I will not wait for mine.

Once all counted, (enrichment, reprocessing, empty running in off-peak hours, etc.) Yamatai what is the actual efficiency of a nuclear power plant? Because the needs are 70% of the energy mix so the demand is there, but is it profitable in the long term, especially in the arrival of thermodynamic solar with storage in molten sodium chloride (between 200 ° C and 800 ° C)

I mean in a reasonable and realistic perspective!


RTDC.

PS: (if you have any figures for studying these questions?)
I accept the answer "I do not know or not exactly"

[Yamatai]

A citro:

For accommodation I took the data insee with 50 kW / h / m² energy efficiency, class A housing
Impossible in reality but it is in the idea of ​​being the most unfavorable to the heat emitted for cooling.

I think these figures are available either at the CIP (Public Information Center) or by asking the water agencies.
It would be quite surprising that there is no communication on our sampling of Loire water.

On enrichment I can answer you partially. In the past, all of Tricastin was needed to enrich the fuel (3600 MWe) by gas diffusion. With the new plant consumption is reduced to 1 reactor (900 MWe) centrifugation I believe.
Production was used by France plus European partners. It must be roughly 100 reactors.
The enrichment principle has changed, I have a colleague who went to see the site will I ask him again his docs.

For reprocessing no idea what consumes the Hague. Many I think but how much?

The output of a power plant nuc.
80% load factor
for an 900MWe the reactor has a power of 2785 MWth.
The output power varies from 890 to 910 depending on the temperature of the cold source and the bearing.

For a CP2 it is 900 to 910 MWe out and 955 MWe to the alternator with a cold source at 22 ° C.
Basically there is 35 to 45MWe consumed by auxiliaries (motors, transformers, heating resistors, etc).
35MWe for a classic site 45MWe for Chinon because aero are forced draft.
Not all reactors have exactly the same electrical power in their engine room. The thermal power is identical to 2785 MWth.

If we take a base of 2785 MWth for 900 MWe the yield is 32,2%.
Enrichment is roughly 9 MWe recently, before 36MWe.
Even rounding to 15 MWe with reprocessing gives a yield of 31,7%.
Extraction no idea what it consumes in energy apart from acid and a lot of water. (yellow cake).

The yield is bad enough, it works because uranium has a monstrous energy power. The efficiency could be improved and it is a little in the newer stages thanks to a margin of vaporization in the lower reactor and higher pressures.

The steam of a nuclear power plant is bad, it is saturated steam at low pressure (about 60 bars). Turbines for good performance require high temperatures and pressures. For this reason, the GCCs display 60% yields. The quality of the steam is very different.

So I do not see too much for performance what figure you expect.
During the maintenance periods the reactor still requires cooling I have never looked at the need.

In first estimate and in view of the necessary systems it is lower than 2 or 3 MWe in band during 20% of the time.

For low load operation (above 60%) auxiliary power consumption is almost identical to full load operation.
The cooling pumps run continuously continuously (15MWe consumed) just like the secondary pumps (condenser supply = 10MWe).

Below 60%, there is usually less power for the condenser. In any case if it is for a long enough period.

As a rule these declines take place on the WE when industrial demand drops.

To have an approximation by counting the slower periods one would have to be looked at on the site of RTE. I think there are the reactors in production hour by hour. There may be excel data extraction possible. In this case with the annual production it should be possible to calculate the total yield. I'm counting on 30% below that would be pretty amazing.

Profitable in the long run no I do not believe it. The EPR is too complex, too expensive.
It may be a seeded new nuclear will be more expensive than the old.
I am to maintain the old one at a good level of security but not rebuilding it.

Except when the merger will be operational. Unlike fission risk management is less or nonexistent and the waste is short-lived.

Paradoxically, the old reactors today are safer now than after their start.
All 10 years they are upgraded with improvements and a battery of tests to check including the containment of the reactor building.

The weak points that condemn a reactor is the state of the tank that does not replace (too big to leave the reactor buildings without cuts) and the civil engineering of the reactor building.
In this respect, the 900 MWe have, for example, a steel skin in the reactor building which is absent in the 1300 MWe. The seal is therefore in theory better.
That is why say for example that Fessenheim is less sure that Nogent is stupid enough. Age is not everything.

Thermo solar home we have a little trouble to see a profitability even with sodium. This is probably more for countries with strong sunshine for alternating day / night.
But after I do not know the self-discharge per day of this storage medium
The solar photo yes without storage means. With storage means it costs but how much?

Will depend on the storage mode. By STEP it is 70% the yield of restitution but still it is necessary to find the sites and to have the agreement.

The batteries, septic when to the mineral resource needed in particular lithium to make them on a very large scale.

Hydrogen 50% refund and very expensive.

Vacuum inertia flywheels and supercapacitors interesting for the regulation of the network and can be in storage with progress.

I remain convinced that for the ENR the STEP is the best current solution to avoid coupled with GCC.

I'm going to digress a bit

Sodium heat transfer has been studied in France in a reactor that everyone knows or pretty much: superphénix.
The concern of sodium is that he does not like water ...
The interest in a nuclear power plant is improved efficiency and used natural uranium alone.

I will have developed a little bit.

By and large the efficiency of the turbine is the proportion of energy that can be withdrawn between the inlet steam and the outlet steam.
The output is at the pressure of the condenser, between 50 and 90 mbar. It is small but it still represents steam at about 40 50 ° C.
This steam for which one takes a turn it is necessary the condensed one. The demand for condensed energy is quite important.

water at 40 ° C = 167 kJ / kg
Steam at 40 ° C = 2570 kJ / kg

The current condensers are efficient it is difficult to do much lower outside of laboratory conditions.
On the other hand it is possible to increase the upper portion.
The efficiency of the ideal turbine is the ratio between what is extracted from the turbine and the total energy expended which includes the condensation condensation to find the liquid state of the water.

This is the reason for the current poor performance of nuclear power. The water in the primary circuit serves as coolant and moderator.
I will dwell on the heat transfer part. To avoid a phenomenon of heating up on the fuel assemblies it is necessary to keep a margin of saturation of the water of the primary circuit.
Consequently the water of the primary circuit is at a pressure of 155 bars for a maximum temperature of 322 ° C and an average temperature of 304 ° C (cold branch at 286 ° C, hot branch at 322 ° C).
In fact, in the boundary layer of the assembly, the temperature is higher. this is why there is a margin to saturation. For 155 bars the saturation temperature is 345 ° C.

The consequence in any case is a steam in the steam generator which operates the heat transfer between primary and secondary circuit of about 60 bars and about 275 ° C.
At Cordemais (coal) the steam is overheated at 150 bars and 550 ° C. The energy potential that can be removed from the turbine is therefore much greater.

Another consequence is that we have a steam of 1 (dry steam) instead of 0,995 and especially very far from the saturation curve.
Very interesting for the turbine which can be smaller, rotated at the speed of synchronism and limited blade wear by the impact of the water present in the steam (lower than 1).

Sodium heat transfer in nuclear allows to achieve the same yields as in the thermal flame. This is the first interest immediately visible. It means less fuel and smaller reactors for the same electrical power.

The second interesting point with this type of coolant and finally the goal of superphénix was experienced fast neutron reactors.
Almost all reactors (except for superphenic cases) are so-called slow thermal neutron reactors. These neutrons will only be able to create fission with enriched uranium (U235) and plutonium (P239).

That is, in a non-MOX assembly (without plutonium) with 4 or 5% max of U235. MOX assemblies are assemblies with less U238 but plutonium. This is a way to recycle the plutonium created during the chain reaction.

Important point during the fission in a thermal neutron reactor the neutrons will be absorbed with a greater or lesser probability by the U235 and P239, they are fissile atoms, they are they which create heat by atomic separation (energy of atomic bond released).
U238 is a fertile atom, ie at this level of energy it will capture neutrons for this transformed into neptunium 239 and plutonium 239 which is a more stable state.

A fast neutron reactor fertilizes much more U238 because there is no more moderator that absorbs neutrons (water generally, formerly and still for some of the graphite). Moreover, the cross section that is the probability of creating a fission during a neutron impact is much more important for the P239 with fast neutrons than thermal neutrons.
A fast neutron reactor thus works with P239 and maintains its P239 creating its P239 by an important fertilization of U238.
The U235 present in the fuel in its natural state (0,7% of the uranium) will also be consumed.

The interest is therefore not to work thanks to 0,7% of the uranium and a small proportion of U235 but with 100% of the uranium.
The marketable reserves are 40 years with a little over 1% actually exploited. I let you do the math with a usage of 100%.

So in summary, the fast neutron reactor is a reactor almost half as big. Less nuclear waste with a long lifespan because the fuel is almost completely consumed but the sodium risk has been managed in addition.
To know if the risk changes the situation on its exploitation I do not know.
This type of reactor is still under study in Russia and the USA. These are the famous reactors of 4th generation. Will they see the day once the sodium risk is sufficiently compartmentalized? Maybe and if it is the case it will be too late to say that it is a pity to have missed the boat because we had a clear lead on this type of reactor initially.

Excuse me for the pavement, I get carried away (in a good way) when I think technical. I may have missed some explanations. Do not hesitate to make me notice.
Sorry also for slaughtering the language of Voltaire I never managed to write cleanly