Consumption of a nuclear reactor: Uranium VS Oil (equivalence)

[Leo Maximus]

What is the mass consumption of a nuclear reactor and its mass equivalent of oil?

A) Heard in a documentary on Russian nuclear icebreakers:

300 g of Uranium equivalent to 350 Tons of diesel over 24 hours.
Real power = 75000hp.

From this we can do some checks and estimates history to have orders of magnitude in mind:

10 kWh per L of fuel oil
11.9 MWh per T of fuel oil

24h thermal power = 11.9 * 350/24 = 173.5 MW
Mechanical power at 35% efficiency = 173.5 * 0.35 = 60.7 MW = 82 hp.

However, the power is given for 75 hp, i.e. 000 kW, hence the actual efficiency = 55 / 500 = 55.5%

Ratio of the masses consumed = 1.2 million. In other words: 1 gram instead of 1.2 Tonne. It's huge".
We can clearly see the interest of uranium in the propulsion of large maritime vessels!

Thermal energy supplied by 1kg of Uranium = 11.9 * 350 / 000 = 0.3 kwh = 13 GWh
Thermal energy supplied by 1kg of fuel oil = 11.9 kWh

And obviously, we find the ratio to approximations near 14 GWh / 11.9 kWh = 1.2 million

B) Corrolary: we can estimate the uranium consumption of an electric nuclear reactor.

Mechanical power of a reactor = 1 GW
Yield = 30%
Thermal power of a reactor = 3.3 GW

Uranium consumption in kg / h for a 1GW reactor at full power = 3.3 / 14 = 236 grams.

The load factor is around 80%, we assume the constant efficiency, so we get:

Daily uranium consumption = 236 * 0.8 * 24 = 4.5 kg
Annual consumption of a 1GW reactor = 4.5 * 365 = 1.6 Tons of Uranium.

In reality in France we have reactors of 0.9GW, 1.3 GW and 1.5 GW so make the corrections: 1.44 T / year, 2.08 T / year and 2.4 T / year

Let us say, given the uncertainty on the load factor and the efficiency: 1.5, 2 and 2.5 T / year. Reactor according to the type.

The interested reader can add up the annual French consumption of uranium for the 58 reactors in operation: http://fr.wikipedia.org/wiki/Liste_des_ ... _en_France
(although at the moment, given the aging of the power plants, we are probably no longer at 80% annual load factor).

Please note that this is not the ultimate waste after treatment.

Read also:
https://www.econologie.com/forums/energie-nu ... t2172.html
https://www.econologie.com/forums/equivalenc ... t5501.html

ps: thank you for not (too) trolling on the nuclear waste debate.

For its current PWR, EDF gives 33000 MW (thermal) day / tonne of uranium. The fuel stays in the reactor for 3 years and is replaced by a third each year. (Source: Michel DURR, EDF Engineer). From there we must be able to calculate the equivalent in fuel oil and knowing that EDF also uses oil-fired power plants, Cordemais for example, we can make comparisons.

If we take the figures given by EDF, 1 kg of uranium used over 3 years is equivalent to more than 3000 tonnes of fuel oil (unless I am mistaken).

But doesn't the comparison between 1 kg of uranium = n * tonnes of petroleum make a little argument for a 50's nucleocrat?

[Christophe]

Can you detail your calculation to arrive at a ratio of 1 kg to 3000 T?

Because I struggle to arrive at this figure ...

According to the EDF engineer:

A) 33000 MW.day = 33 * 000 = 24 GWh / Tonne of uranium (consumed year-round?)

Over a year, we therefore have 792 * 365 GWh / 2/3 Ton of uranium, is that it?

On a day 792 GWh = 792 kWh = 000 liters of fuel oil ... at 000 density we have a mass ratio of 79 T fuel oil for 200 / (000 * 0.8) = 63000 Tons = 2 kg of uranium ?

Report: monstrous (too much)!

B) If it is 1 ton consumed per day to make the 792 GWh then we would obtain a ratio of 1 kg for 63 Tons? Which remains consistent (order of magnitude) with the figures above.

I presume that the disparity comes from differences in enrichment and / or if we are talking about fissile or raw uranium?

[Capt_Maloche]

According to Wiki:

It is a radioactive heavy metal (alpha emitter) with a very long period (~ 4,5 billion years for uranium 238 and ~ 700 million for uranium 235). Its low radioactivity, added to that of its descendants in the decay chain, generates a power of 0,1 Watt per tonne, ce which in fact, with thorium (four times more abundant, but three times less radioactive), the main source of heat which tends to maintain the high temperatures of the Earth's mantle, considerably slowing down its cooling.

The 235U isotope is the only natural fissile isotope. Its fission releases an energy close to 200 MeV per cracked atom. This energy is more than a million times greater than that of fossil fuels for an equivalent mass. As a result, uranium has become the main raw material used by the nuclear industry.

so we are talking about Uranium Pur

[Christophe]

Ok so here we find the report to 1 million that I had estimated in the 1st message ...

Problem: pure U235 = 100% enrichment with U235, which is not the case in reactors (4% enrichment in France)!

[Leo Maximus]

Can you detail your calculation to arrive at a ratio of 1 kg to 3000 T?

Because I struggle to arrive at this figure ...

According to the EDF engineer:

A) 33000 MW.day = 33 * 000 = 24 GWh / Tonne of uranium (consumed year-round?)
.... I presume that the disparity comes from differences in enrichment and / or if we are talking about fissile or raw uranium?

Well ... I don't pretend to be an atomic physicist but it's more complicated than that. This is what I read in document D28 from EDF, it dates from before Chernobyl but it was (AMHA) more reliable than what is said today, for example that curium or americium are no longer fission products :

"The use of fuel in a PWR type reactor corresponds to the fission of part of the U 235 it contains, of a small part of U 238 (direct fission possible by higher energy neutrons at 1 MeV), to irradiation and to the capture of neutrons by U 238 which will give Pu 239, to the fission of a part of this plutonium, to the irradiation of another part to give Pu240 and Pu241 then transuranium elements such as curium, americium, californium.

The energy released comes for:

51,3% of U 235 fissions
8,3% of U 238 fires
35,3% of Pu 239 fissions
5,1% of Pu 241 fissions"

So, in the tonne of fuel producing 33000 MW.day there are 48,7% of elements other than U 235, it is considerable, it is almost half.

[jonule]

good information on the pollution of nuclear fuel manufacturing, in all its chain, quite clear:

http://groupes.sortirdunucleaire.org/Nu ... 310#ecran2

it's not just mines, power plants and waste that pollute, but also the transformation of ore into fuel, which pollutes continuously the environment, and our children ...

"
1. From yellow cake to uranium tetrafluoride (UF4)

After being extracted from rock in mines on the other side of the planet, uranium is transported to France by boat, in the form of yellow cake, a yellow paste. Once arrived at the port of Le Havre, Sète or Fos, this yellow cake is transported by train to the Comurhex Malvési factory near Narbonne. It will be purified and transformed into uranium tetrafluoride (UF4), a substance which, in contact with air humidity, can generate a toxic and very corrosive solution which can pierce the glass. The UF4 is then routed daily by road to the Comurhex Pierrelatte, located on the Tricastin site). 3 to 5 radioactive and dangerous trucks use the A9 and A7 motorways every day in total secrecy.

The installation includes numerous open ponds, settling, evaporation, lagooning and storage of more than three hundred thousand tonnes of radioactive nitrate sludge. CRIIRAD revealed in 2006 that some of these basins still contain traces of plutonium, an extremely toxic and harmful substance.

The plant uses radioactive and chemical products (nitric acid, ammonia, hydrofluoric acid) and releases toxic substances into the environment, thus polluting water, air and soil.

Numerous accidents (flood, breakage of a dyke ...) have been recorded in recent years in Malvési.

In addition, between 2006 and 2009, the installation operated illegally, without having obtained the status of basic nuclear installation.

2. From uranium tetrafluoride (UF4) to uranium hexafluoride (UF6)

The uranium, in the form of UF4, is then transported by truck to the Comurhex plant in Pierrelatte, at the Tricastin site in the Drôme to undergo further processing. After numerous manipulations, which also release radionuclides and carcinogenic chemicals, the uranium will be transformed into uranium hexafluoride (UF6). This form of uranium is a corrosive, very active and harmful chemical compound which reacts violently with both water and air humidity.

UF6 is just one of the many risk substances that can be found on the Tricastin site, a real time bomb with an exceptional concentration of radioactive materials.
The operator is regularly pinned by ASN for poor management of materials on its site.

3. From uranium hexafluoride (UF6) to enriched uranium

Once these two transformation steps have been carried out, the uranium will be enriched because the uranium is too poor in uranium 235 to be able to be used in reactors.

In France, enrichment is carried out at the George Besse factory, belonging to AREVA, also located on the Tricastin site. The George Besse I installation, which operated from 1978 to 2012, is now shut down. On June 7, 2012, the George Besse II plant definitively took over for the enrichment of uranium, now carried out by centrifugation.

This new transformation step uses a dangerous and proliferating technique and again leads to chemical releases and radioactive pollution. Indeed, this technique facilitates access to the atomic bomb and is therefore proliferating. Because to obtain uranium enriched to 90% which goes into the making of bombs, it suffices to continue enrichment well beyond the 4% required for reactors ...

This process also produces considerable amounts of waste, in the form of depleted uranium, which is either stored as is or reused to make depleted uranium weapons that have been used in recent conflicts.


4. From enriched uranium to nuclear fuel

Once enriched, the uranium is then transported (generally by train, but currently by truck, the railway being under construction) to the FBFC plant, in Romans-sur-Isère. It will be packaged there in the form of pellets which will be placed in tubes, called "rods", to form the nuclear fuel rods. This fuel will then be transported by train to the 19 French power stations.

FBFC, a subsidiary of AREVA, is the world's leading producer of fuels for pressurized water nuclear reactors (PWR).

The FBFC factory, which handles enriched uranium, is a high-risk site, in which the safety culture leaves something to be desired ... In 2011, the site had to report 15 significant incidents to the Nuclear Safety Authority , which criticizes the slowness with which security improvements are implemented.
"

I don't know if it was on the "c'est pas sorcier" show?

I do not put the links of evidence of pollution and other controversies, to know more:
http://groupes.sortirdunucleaire.org/Nu ... 310#ecran2

[Christophe]

Jean-Marc Jancovici also talks about the equivalent of 1 g of uranium to 1 g of oil in this video, around 000 am:

As it is the same figure that I had calculated in 2010 above, I presume that it speaks of Uranium 238 enriched 4% of fissile U235 used in current plants ...