Nuclear

[Other Means]

d/w - since we've heard no more about this, shall we assume that was scaremongering as well?

[__Yossarian0815[jby]]

you can read about the design of the chernobyl reactor here:

http://www.rri.kyoto-u.ac.jp/NSRG/reports/kr79/kr79pdf/Malko1.pdf

The core is constructed from closely packed graphite blocks. They are stacked into columns with vertical

cylindrical openings into which channels for fuel (pressure tubes) as well as channels for absorbing rods

are inserted.

At the time of loading the core with fresh fuel, one part of fuel channels (230-240) is loaded with

special additional absorbing rods (AAR) because the control rods can not compensate the large reactivity

surplus of the core [7]. The geometrical parameters of the AAR rods do not differ from those of fuel

assemblies. Therefore, the additional absorbing rods can be inserted at any channel of the core. With

increase of the fuel burnup the AAR rods are withdrawn gradually one after the other. The fuel assemblies

are inserted then in the channels that were occupied previously by additional absorbing rods. Thus, the

weight of uranium in the core increases with increase of fuel burnup. At the beginning of operation it is

about 165 t and reaches 192 t by achieving the stationary operation

Control and protection system

The control and protection system (CPS) of the RBMK reactor has absorbing rods and different

measuring devices for a control of a number of parameters. There are 211 absorbing rods in case of the

RBMK reactors of the second generation [3,4]. According to their functions they are divided in 4 groups

[7]:

- shortened absorbing rods (SAR) for regulation of the axial neutron distribution;

- absorbing rods for a manual regulating of the radial neutron distribution (MR);

- absorbing rods for an auto control of the reactor power (AC);

- emergency rods (ER).

The total numbers of the SAR, AC, MR and ER absorbers are 24, 24, 139 and 24, respectively [4].

The absorbing rods used for control and protection systems of the RBMK reactor are assembled from the

identical absorbing elements made of carbide boron [7]. These elements have the same length equal to

967.5 mm. The absorbers of the type SAR have only three absorbing elements. Their length is 3,050 mm

[7]. Other absorbing rods are assembled from 5 absorbing elements. Their length is 5,120 mm [7]. There

are another feature in absorbing rods of the RBMK reactor. The absorbing rods of the type SAR, MR and

ER have special graphite displacers that are assembled from 5 graphite elements. These displacers remain

in the core by full withdrawal of absorbing fractions of rods. The use of graphite displacers improves

significantly the neutron economy of the RBMK reactor because graphite absorbs neutrons much less than

the light water.

To sum it up: Chernobly was permanently moderated by graphite and controlled by moveable neutron absorber rods. These rods had graphite at their tip to make up for the missing moderation at those points at full load, that is with the rods retracted. So Bigduke was right in the sense that the reactor is permanently "out of control" unless dampened, only the dampening is not moderation, but neutron capture.

[Other Means]

BTW, this might come in handy when talking about "legal" levels and "safe" levels:

[JonS]

This seems apropos.

[Other Means]

Not as relevant as The unpalatable truth is that the anti-nuclear lobby has misled us all , George Monbiot.

[dieseltaylor]

OM that chart was very good. I like it.

The interesting thing is the mixing of daily and annual amounts and I was wondering if there was a third way to plot. The daily rate for the two sites near Fuku quoted mean that there is certain damage after a month - if the rates remain at that level, and over a year 50% of the way to certain radiation poisoning.

What is not clear is to whom this relates - I imagine it is for adults and the doses to damage children and foetuses is a lot lower.

[dieseltaylor]

Re: Monbiot.

Unfortunately he seems to be coming wiser by degrees in some areas. To be honest whilst concerned with humans, it is the long term poisoning of the earth which is more of a problem. And waste storage is a problem unless they can get thorium to work or something better. As for most power it depends how you do the costings as to whether it is truly cheap.

I find this whole damascene conversion quite bizarre. But it is perhaps the nature of extremists to mutate from one "evidence" based policy to another with little rational input. With regard to the health effects of radiation perhaps the reason for so little "scientific" literature is that the effects were felt to be so well known as to not need repetition. In this regard I would suggest that George returns to read the heroic stories of the scientific pioneers such as Marie Curie and the brave souls who ran the Manhattan project and the victims of Hiroshima. Aside from the effects of the radiation itself the metals themselves are highly poisonous chemicals in there own right.

If George cares to look at the FDP plan for Chapelcross (in SW Scotland) the costs assuming an interest rate of 3% for decommisioning over one hundred+ years are 1.6-1.8 billion at todays prices. No one will have access to that site for one hundred years.

Now multiply Chapelcross across the world by the amount of nuclear reactors required and the lunacy of your position becomes apparent.

It is a sad fact that few polities in the world are more than 100 years old, and that therefore the liklihood is that at least one failed state will arise with nuclear power. In Japan the 9.0 earthquake is a c. 100 year event the problem with nuclear, is that it is around for so long that 100 year events are bound to happen and the more stations there are the larger the number of accidents.

A final point the lifetime output of Chapelcross (which ran for 20 years longer than spec) was 60 Tw/h, the current wind output in Europe is 11 Tw/H for an investment of 11 billion- and no nasty aftertaste.

This from the Swedish nuclear industry site:

We currently have a well-functioning system of managing and disposing of nuclear waste. Both a final repository for operational waste and an interim storage facility for spent nuclear fuel have been in operation since the mid-1980s.

Over a period of three decades we have been developing a method for safely handling and storing the spent nuclear waste for long periods of time. We have conducted research and development, and performed studies and investigations. Several technical breakthroughs have occurred during this period.

We are currently preparing the parts of the system needed to begin the encapsulation and final disposal of spent nuclear fuel. The latter is the hardest to handle, since it requires that waste be isolated for at least 100,000 years.

100000 years is a very long time indeed. I have no doubt that if mankind does not relapse into chaos a solution would be found in the next two centuries .

[Other Means]

Re-processing waste can take the dangerous life of it down to 50 years apparently and LFTRs don’t produce any. Of course if you really, really want to get rid of it just bury it in a tectonic subduction zone and watch it return to the mantle.

Your first quote there is factually wrong in at least one respect – the earthquake that hit Japan was a one in a thousand year occurrence. TBH, I wouldn’t give the vox-pop from any article any credence, it will just get us into tit-for-tat cross posting and reference checking, e.g. I've read that particular comment countered on something like p24 where it gives completely different figures for decommissioning.

I don't have time to do that unfortunately.

[dieseltaylor]

OM - it was a reply in the Guardian to Monbiots piece.

You do raise the probability issue. The Indonesian quake in 2004 was a 9.1 so bigger than the Japanese quake. We must think ourselves fortunate that they had not built any of those reactors they want. Anyway that was recorded as the third biggest since 1900 which makes me wonder how you can be sure that any fault will be dormant for 1000 years.

http://www.abc.net.au/news/infographics/earthquakes/

Here are the biggest recorded quakes on a map:

http://www.ga.gov.au/earthquakes/list.do?isRegionSelected=false&region=WORLD

However the destructiveness of a quake is surely to do with the depth under the earth and the way the tremors act. Wikipedia is actually more useful than the Australian site.

Great earthquakes occur once a year, on average. The largest recorded earthquake was the Great Chilean Earthquake of May 22, 1960, which had a magnitude of 9.5 on the moment magnitude scale.[8]

Now earthquakes are the release of prssure caused by the tectonic plates moving so one would like to think tht they would occur infrequently. However the great earthquakes 8+ do seem to cluster somewhat.

[Other Means]

d/t, yes, I read the same comment, hence mine above.

[dieseltaylor]

I once absend-mindedly ordered Three Mile Island dressing in a restaurant and, with great presence of mind, they brought Thousand Island Dressing and a bottle of chili sauce.

-- (Terry Pratchett, alt.fan.pratchett)

[Kanonier Reichmann]

I just realised that the spelling to the title of this thread must be wrong. It should be "Nucular". If it's good enough for George Dubya it must be good enough for the rest of the population.

Regards

KR

[__Yossarian0815[jby]]

Re-processing waste can take the dangerous life of it down to 50 years apparently

So why isn´t anbody doing it?

and LFTRs don’t produce any.

So why isn´t anbody building any?