Possible Nuclear Leakage at Power Plant.

The reactors may not be generating,  but the fuel and much of the remains are  still very hot, both thermally and radioactively, and given how it failed this includes many things that would not normally be radioactive after a normal swtch-off. This needs to be safely contained. Keeping the power on to monitor how hot and to keep the cooling on is important, it should survive short term interruptions just fine, but there are (or at least were, not sure now, to be fair ) 1000 or more folk employed pretty well  full time just keeping the site in a safe state. It may not be very exciting, but it still needs doing.

Mike.

New Scientist is also saying risk is low in the short term of hours and days but in the coming  weeks power for water cooling will need to be restored to keep it safe.

https://www.newscientist.com/article/2311591-chernobyl-power-cut-sparks-fears-of-potential-for-radiation-leaks/

So no panic today.

Mikw.

The BBC's version seems a little more balanced than the DM's: https://www.bbc.co.uk/news/world-europe-60678598

   - Andy.

Nothing new there then!

Radioactive material (including exposed components) will remain so for many thousands of years. For many years hence, many of those components will also be hot, due to the radioactivity. The sarcophagus thus needs active environmental control, and will do so for many years hence. Active environmental control means control systems and currently these use external power, and will do so for the foreseeable future. Take that power off, you lose your control. 

Many people still do not seem to understand that, when you build fission power plants, you are committing yourself to significant active control of that plant and of what remains of its components for hundreds to thousands of years. I for one am not convinced that we humans are wise enough or responsible enough to take on such task (such a series of tasks, geographically widely distributed). Recent events have done nothing to persuade me otherwise. 

Another point. What on earth does this have to do with "Wiring and the Regulations"?

You're not from round these parts I assume.

132.5.1. and 132.5.2.

Z.

I presume it is wires to the plant that have been cut by the Russian soldiers out on their 'special operation', it is therefore wiring, though my previous exposure to eastern bloc wiring leads me to think the house style  will probably be some way off BS7671 ;-).

Anyway cooling ponds are pretty good so long as they stay full of water - then at least in terms of neutron flux, the danger to life  falls off pretty rapidly. This XKCD article is probably not quite right but the numbers are close.  The water itself gets contaminated of course but the solution to pollution really is dilution when it comes to this sort of thing.

The risks arise if it runs dry. Vast amounts of lower level waste are not such an issue.

In terms of other stuff becoming radioactive, things with really long half -lives are safe because during a human life span the total dose is small- after all it is safe to sit on Exemoor and eat your sandwiches, illuminated by ~ 10 u Sv , even though this is 100 times more than other places nearby.

Spent fuel is indeed very dangerous when it is unloaded, and how it decays depends which isotopes you consider, but after 30-40 years the water cooling is no longer required, energy output being a fraction of a percent of that when unloaded. Now to get that back down to near-natural levels of radioactivity may take a further 1000 years, but the first 100 years of that are the most dangerous.

In the UK for example according to a recent survey we have (source) 1390 cubic metres of high level waste (the stuff that needs cooling.) If it was safe to put it in one place that would  be a cube of 11m side.  Or if you prefer about the volume of one semi-detached house, that needs to be under a few metres of water for a few decades. Then there is a lot more (247,000 cubic metres - large block of flats size) intermediate level waste, that does not need any special cooling, but radiates enough that you really do  need to keep folk well away from it. This includes fuel that has been cooled in ponds already, and other parts such as system containment. Usually this is cast in to concrete in steel boxes and then buried.  The calculation is that by time that the containment has failed it has decayed enough not to matter.
Then there is low level waste, that is close to  the same category as that picnic lunch on Exemoor where you could sit on it to eat your sandwiches, but  it would add a noticeable amount to your annual dose, to do so repeatedly would not be wise. This again we bury but with less strict rules about where.
Very low level waste can pretty much go with the rubbish in the dustbin.
One complication is that for very good historical reasons we do not, or at least did not, distinguish high concentrations of long life and low concentrations of  short life isotopes very well in our handling processes, and arguably we waste quite a lot of effort containing things in a way that is stable for centuries, even in some cases where a ten year wait would have reduced the level a point where it was no longer necessary.

Breeder reactors and systems to 'burn' plutonium as one of the nasty byproducts, are something that probably need more thought, at the last count we had between 100 and 200 tonnes of the stuff in the UK

(link) discussing some of the options there.

Mike.

Mike.

Protect and Survive.

https://www.youtube.com/watch?v=7yrv505R-0U

Z.

Basic physics. Highly radioactive materials decay quickly, low activity materials decay more slowly. There is no 'natural' Plutonium 239 because it has all alpha decayed to Uranium 235.