Did you know ? Questions answers ecology and energy.

Oil, gas, coal, nuclear (PWR, EPR, hot fusion, ITER), gas and coal thermal power plants, cogeneration, tri-generation. Peakoil, depletion, economics, technologies and geopolitical strategies. Prices, pollution, economic and social costs ...
caribou
I learn econologic
I learn econologic
posts: 29
Registration: 05/07/08, 13:31




by caribou » 30/07/08, 10:33

What is the share of nuclear power in global electricity production?
I heard on Inter surprising figures ... 2% for nuclear, 12% for renewable (the type did not specify if it included hydraulics in it) and the rest for coal / oil / gas plants.
2% makes it completely unrealistic to develop nuclear power plants worldwide given the exploitable uranium reserves (30 years at the rate of extraction and use with current technology).
I tried to corroborate these figures but impossible to find two sources which say the same thing ...
0 x
C moa
I posted 500 messages!
I posted 500 messages!
posts: 704
Registration: 08/08/08, 09:49
Location: Algiers
x 9




by C moa » 08/08/08, 11:37

Hello everybody
I just discovered your site and I find it good that at last people reflect on the environment in a relatively objective way, with generally well documented sources, without too many unnecessary passions on such an important subject.

Thank you to the instigators of this site.


Did you know ??
When an oil field is considered exhausted, this means that between 25 and 35% of the oil it contains has been removed.

Did you know ??
When a fuel rod is removed from a nuclear power plant core because it is said to be too worn. It will in fact be more than 97% reused after being recycled.
0 x
Christophe
Moderator
Moderator
posts: 79120
Registration: 10/02/03, 14:06
Location: Greenhouse planet
x 10973




by Christophe » 08/08/08, 11:42

Hi there and welcome! 8)

Well your 2 "did you know".

a) For the oil extraction rate here is a statistical curve:

Image

Recovery rate found or considered (on the vertical axis) for 3300 world's oil fields, depending on the tank size (that is to say the amount of oil physically underground), expressed in billions of barrels (along the x axis). 1 159 barrel = liters.

Source Jean Laherrère, Petroconsultants, 1997


Source: http://www.manicore.com/documentation/reserve.html


b) I did not know for the 97% ... I suppose that you speak en masse of the pencil? What is it recycled for? The nuclear industry and I do it 2 :D : Cheesy:
0 x
C moa
I posted 500 messages!
I posted 500 messages!
posts: 704
Registration: 08/08/08, 09:49
Location: Algiers
x 9




by C moa » 08/08/08, 12:14

Christophe wrote:Hi there and welcome! 8)
b) I did not know for the 97% ... I suppose that you speak en masse of the pencil? What is it recycled for? The nuclear industry and I do it 2 :D : Cheesy:

In fact, when you consume a kg of coal or a liter of fuel oil to make electricity, when you have finished using it, "only" soot and CO2, NOx are left ...

In a power plant, when a fuel rod is removed, because it is considered worn, it goes to a reprocessing center. The objective, in a very simplified way, is to separate the ultimate (long-lived) waste from the parts which can again be used in future brand new pencils. With this process, more than 97% of the old pencil will be used to make a new pencil.
In some pencils (called MOX), part of the final waste (mainly Pu) is added to improve the yields of the pencils. In this case, reprocessing makes it possible to recover nearly 99% of the "spent" fuel.
0 x
Christophe
Moderator
Moderator
posts: 79120
Registration: 10/02/03, 14:06
Location: Greenhouse planet
x 10973




by Christophe » 08/08/08, 12:36

Ah I see that we are dealing with a nuclear specialist (beware of dumpling if you come across it ...).

So a correlative question: from which mass loss is a pencil considered to be worn?
0 x
C moa
I posted 500 messages!
I posted 500 messages!
posts: 704
Registration: 08/08/08, 09:49
Location: Algiers
x 9




by C moa » 08/08/08, 14:22

Christophe wrote:Ah I see that we are dealing with a nuclear specialist (beware of dumpling if you come across it ...).

Specialist not really, I worked there for a while and it is a very interesting industry technically. But I left nuclear a few years ago now so ...
Christophe wrote:So a correlative question: from which mass loss is a pencil considered to be worn?

To my knowledge, this is not a question so much linked to the loss of mass as to its time of presence in the reactor.
Indeed, the weak point in a pencil is above all its envelope which is constantly subjected to very aggressive radiation. In addition, fission also produces gaseous products which necessarily increase the pressure inside the envelope.

Overall, we change 1/3 of the pencils on each reload. On REP 900 this means that they will stay for a maximum of 3 years, on REP 1300 and 1450 approximately 4 years, 4 and a half years.
0 x
Christophe
Moderator
Moderator
posts: 79120
Registration: 10/02/03, 14:06
Location: Greenhouse planet
x 10973




by Christophe » 08/08/08, 14:27

Uh ok thanks for the details. You will no doubt be able to answer some of our questions (mine already!).

During these years what mass will have lost the pencil (in%)?

What is the pencil consumption (in tonnes) of an REP 900 on average?

Are these the same pencils in all French reactors?

Finally how much uranium must be consumed to produce 1 GWh?
0 x
C moa
I posted 500 messages!
I posted 500 messages!
posts: 704
Registration: 08/08/08, 09:49
Location: Algiers
x 9




by C moa » 08/08/08, 18:27

Christophe wrote:Uh ok thanks for the details. You will no doubt be able to answer some of our questions (mine already!).

During these years what mass will have lost the pencil (in%)?

What is the pencil consumption (in tonnes) of an REP 900 on average?

Are these the same pencils in all French reactors?

Finally how much uranium must be consumed to produce 1 GWh?

Well I did well to say that I was not a specialist because that's it I dry on some questions : Lol:

- I do not know precisely the mass that is lost but at first glance I would say almost not. Indeed, there is very little fissionable material in the pencil (4% if I'm not mistaken) and at the end of its life, it is not sure that all of this 4% has been consumed. . In addition, as a great scientist said "nothing is created, nothing is lost, everything is transformed" and this also applies to nuclear power. Overall when a uranium nucleus is broken (fission reaction) it splits into two smaller nuclei (fission products), releases neutrons and in general also releases an alpha and like all this matter being trapped in the envelope of which we spoke above, the fission products and the alphas remain within the pencil. The only particles that "escape" are neutrons of relatively negligible mass. Now if more experienced people can complete ....

- In a REP 900, we have approximately 75 tonnes of assemblies. Assuming that we replace 1/3 every year, I would say 25 tonnes .... Again to check.

- To my knowledge, there are two types of rods, the "UO2" which contain natural uranium "doped" with enriched uranium and the MOX which contain natural uranium "doped" with plutonium. To my knowledge, we can put UO2 in all PWRs but for MOX, the ASs must give their agreement.

- I cannot answer the last question precisely because it is more complex than it seems. We could simply take the overall annual uranium consumption (around 1000 tonnes I think) and divide it by the potential energy produced (Installed power around 63 Gwatts if I remember correctly, ie 552000 GWh of potential energy produced) but (there is always a but) in this case we would not take into account that the annual production is necessarily less than 63 Gwatts due to outages, decreases in production requested by managers ... Now, we can make a big (very big even) approximation. If we consider an availability rate of around 70% (to check), this means that we can potentially use only a little more than 44 GW of power or produce a little more than 385000 GWh per year.
For a 1GWh, it would therefore be 1000 tonnes / 385000 GWh produced or 0.0026 tonnes if I am not mistaken. Overall I think I remember that EDF was advertising a few years ago where they said that it took a gram of uranium to produce electricity for a family of 4 people for a year. It is very weak. For those who want to give me more reliable figures, I am also a taker !!!
0 x
C moa
I posted 500 messages!
I posted 500 messages!
posts: 704
Registration: 08/08/08, 09:49
Location: Algiers
x 9




by C moa » 08/08/08, 18:56

By the way, I wanted to react to a post that is a bit dated.

Some speakers said that the power plants' yields were 30% and therefore that 70% of the energy went into steam in the towers and therefore that it was a shame not to bump with it.

Certainly, nuclear power plants have a slightly lower efficiency than other technologies but not that much:
- Nuclear power plants: around 35%;
- Thermal power stations: just over 40%;

And above all the loss items are much larger than we think:
1- The recovery in the primary circuit of the energy produced by fission is not 100%;
2- The transmission of energy between the primary circuit and the secondary circuit is also a source of loss;
3- The steam generator also;
4- The transmission of steam to the turbogenerator also;
5- transfer between the secondary circuit and the cooling circuit;
6- types of cooling have more or less effective yields also.

The main losses occur in the first 4 stages and it is difficult to recover these calories. This is not why nothing should be done, the last two positions are also important. Several plants do cogé. In Chinon, for example, part of the calories are used to heat local businesses and greenhouses.
0 x

Go back to "Fossil energies: oil, gas, coal and nuclear electricity (fission and fusion)"

Who is online ?

Users browsing this forum : No registered users and 276 guests