I am an experienced nuclear power worker - Ask Me Anything

[tma]

I realise the nuclear plant situation in Japan is a concern for a few people, and that there are confusing and conflicting media reports from largely uneducated journalists who can't wrap their heads around the subject

Comments

[speaktothevoid]

I just read an article by Michio Kaku about the situation. Do you agree with his analysis and proposed 'solution'?

[tma]

No, not at all. The reactor design means that unlike Chernobyl you don't have a huge source of combustible material as they did with the graphite core. The reactors are being cooled with sea water until the point where the decay heat is low enough so they can remove the damaged fissile material and store it elsewhere - keep it nice and wet and cold and you won't get any nasties getting out into the wider environment.

[demiraks_world]

Is that sea water being contaminated then? Or is it not even coming in contact with the radioactive stuff?

If it is being contaminated - what do they do with it?

[tma]

The seawater will become contaminated due to the core damage that is assumed to have occurred in the reactors. I'm not entirely sure what they're doing with the sea water once it's been pumped into the reactor to cool it. Clearly the water is going to get hot and eventually turn to steam if the circuit is allowed to get warm.

Without main power at the site it's not easy for them to run their circulating water pumps through their condensers to cool down the water they pump into their primary circuit. These are facts that will come out in time.

I can say that sites do have large liquid radwaste storage containers, and these can be used as an option for storing excess liquid waste prior to running it through resin beds and filters before returning it to sea if the contamination is low enough.

[yuriko]

What's the worst that could happen, and how likely is it?

[tma]

The worst that could happen is they lose the ability to pump the pacific ocean into the stricken reactors, resulting in them boiling dry. The consequences of this would be the core ending up on the floor of the respective containment buildings, and should there be a breach in the containment building, you could get fission products into the environment. Since there wouldn't be a huge fire, like at Chernobyl, due to lack of combustible material in the mostly concrete containment, it wouldn't be anywhere near as bad.

[emptykettle]

where do you work?

[tma]

I work at a modern pressurised water reactor in the UK, the name of which I shall omit since I don't want to become a semi-official source.

[darkblysse]

I had no idea. Your awesome points just skyrocketed; and they were already pretty high before.

[mofoburrell]

PWR uses passive safety, right? Does this mean the reactors naturally shut themselves down without people tending to them? Do all new reactors use passive safety these days?

[__45rpm__]

There has been a run on Potassium Iodide on the West Coast. Is this paranoid thinking or smart planning?

[tma]

If I were a producer of KI I'd probably try to make the most of it, cynically. But no, the west coast of the states is a long, long way from Fukushima, and the radiological releases are pretty small beer.

[__45rpm__]

That's good news.

[leafing]

Do you think the current situation with the nuclear power plants in Japan are going to severely set back the nuclear power industry worldwide/in your country? It's not every day that a country gets totally spanked by earth like that, but my gut feeling says that people are going to get all reactionary and say that nuclear power is totally unsafe etc. etc. etc.

[tma]

I know you think about me, but I didn't realise it was restricted to this subject :p