Nuclear Power

[johnb]

Lat,

With the best will in the world much of your last post is of very dubious validity, to say the least.

You say "One of our current plants is of a Chernobyl design and it is on a fault line."

Which would that be?

According to what I have heard/read the Chernobyl design was rejected by the UK and other western countries as it was crude and potentially dangerous even at the time it was built.

"It seems that according to eminent scientists there is still the possibility of significant radiation travelling around the whole of the northern hemisphere if the attempts at cooling don't work. "

Can you give a link to that view as it is direct contradiction of the opinions that I have heard expressed?

[Paul N]

One of our current plants is of a Chernobyl design and it is on a fault line.

Really?!! Which one is that may I ask?

The reduction in GB nuclear (and coal) occured as a result of privatisation and the fact that gas stations were cheapest and quickest to build. They brought diversity into the generation mix, which was welcome. We don't really need many more of them though, as we are now highly dependent on gas imports.

[Lateralthinking1]

johnb - I didn't mention it because I didn't want to spread alarm in that area. However, it has been covered in the press in the past. I am referring to Heysham.

On the point about the northern hemisphere, I have read a lot in the last few days but I will see if I can locate a suitable link. Lat.

[MrGongGong]

It does seem important to be fastidiously accurate in these kind of things
I'm not a scientist BUT do know that earthquakes are no longer measured on the Richter scale
having read this I then (quite naturally) tend to be very suspicious of the whole argument
phrases like "the science shows" are usually used by politicians when they want to push some idea that more often than not the "science" doesn't show at all !
who are these "eminent" scientists ?
I'm not disagreeing with worries about Nuclear Power but accuracy and facts are important

[Lateralthinking1]

....on the point made by frances_iow, I fully accept that the distinctions are important. In one of the posts above, I reminded people of what high readings on the Richter Scale meant. For the sake of completeness -

-3.9 Often felt, but rarely causes damage.
-4.9 Noticeable shaking of indoor items, rattling noises. Significant damage unlikely.
-5.9 Can cause major damage to poorly constructed buildings over small regions. At most slight damage to well-designed buildings.

A brief summary of the more significant ones in the UK - http://news.sky.com/skynews/Home/Sky...20080641263233

Detailed list of UK earthquakes - fascinating - http://www.earthquakes.bgs.ac.uk/ear...al_listing.htm

London Overdue a Major Earthquake - http://www.guardian.co.uk/science/20...ience-festival

Bristol Channel - Tsunami - http://www.burnham-on-sea.com/1607-flood.shtml

UK Tsunamis - http://en.wikipedia.org/wiki/Tsunami...United_Kingdom

The moment magnitude scale which has replaced the Richter Scale (the latter still important for historical reference) gives similar readings to the Richter for magnitude 3 to 7. This means that the 8.9 in Japan, stated by many as exceedingly rare, which it is, may not be quite as unusual (or severe?) when considered alongside earlier Richter figures.

[johnb]

johnb - I didn't mention it because I didn't want to spread alarm in that area. However, it has been covered in the press in the past. I am referring to Heysham.

I'm sorry but both of the Heysham reactors are of the advanced gas cooled type and are very, very different to the Chernonyl design, even though they both use graphite rods as moderators.

I do wish people would actually check whether what they are saying is correct before writing. For heaven's sake - it only needs a few clicks on Google.

[MrGongGong]

BUT the Richter Scale isn't used anymore ?
which really undermines the credibility of your arguments
(which I don't necessarily disagree with !)

[Lateralthinking1]

As promised, on the possible spread -

http://rt.com/usa/news/nuclear-radiation-japan-usa/

[Lateralthinking1]

johnb - On Heysham, I accept that it is an advanced gas-cooled system. However, as you say, graphite rods are used as moderators. Additionally, would I be right to say that like Chernobyl, there is a single line of defence, not all of the plant was originally designed to withstand earthquakes (now a standard requirement), there is just a single integrated and shutdown control system - the safety critical systems run on UNIX-based boxes, and that much of the internal computerisation is ancient? Lat.

[MrGongGong]

johnb - On Heysham, I accept that it is an advanced gas-cooled system. However, as you say, graphite rods are used as moderators. Additionally, would I be right to say that like Chernobyl, there is a single line of defence, not all of the plant was originally designed to withstand earthquakes (now a standard requirement), there is just a single integrated and shutdown control system - the safety critical systems run on UNIX-based boxes, and that much of the internal computerisation is ancient? Lat.

Is that ancient like the Richter scale ?

[Lateralthinking1]

The Richter is the easiest method of conveying levels of risk simply. Transparency is useful. It also provides significant historical context. The scales currently being used tend to provide measurements within 0.6 of the Richter. I don't think that we need get too hung up on the differences.

Back in the "precise" world of science, certain risk assessments of nuclear installations are based on the ALARP principle - "as low as reasonably practicable". That is an example of approximation that could just make a real difference. The problem is that there are no means of reducing the level of risk further. One can live with that if it applies to a boat or even a plane but the nature of this industry and its potential impacts are entirely different.

(Incidentally, the Japanese probably felt that they would be unlucky to experience a 7.9 and planned accordingly. Here we are saying that in the UK we would be unlucky to get a 6.0 and are doing the same. The difference between a 6.0 and a 7.0 could be fundamentally important, just as the difference between a 7.9 and a 8.9. We also need to bear in mind that this is just one component of the risk - others include system failure, wear and tear, and human error).

[Frances_iom]

the safety critical systems run on UNIX-based boxes, and that much of the internal computerisation is ancient? Lat.

Would you prefer a Windoze box - with its BSOD.
Passing within 200m of Heysham twice a month I should say the last exciting thing to happen there was the Manx Ferry banging into the quay in a force 10 gust - I think at present Heyshem is working at nothing like full power (not seen any activity on the railway used to move fuel for some years). It would however be very convenient if you could give me an estimate of the date of the next expected quake at Heysham so I can avoid travel on that day.

[MrGongGong]

it might be the "easiest method of conveying risk"
(and i wouldn't know !) but you seem to be the only expert who still uses it

[Frances_iom]

... based on the ALARP principle - "as low as reasonably practicable". That is an example of approximation that could just make a real difference. .

all civil engineering is based on similar ideas when it come to highly unlikely events - Thames Barrage etc - your postulated major quake in the apparently high quake activity of the Dover Straits could destroy the channel tunnel with significant loss of life but I trust the geologists have estimated the probablity to be so small that only those non-scientists who think that absolute certainty is possible would be worried.

[Lateralthinking1]

Quote - "but you seem to be the only expert who still uses it" - I have never been an expert at anything. I doubt that anyone ever has.

Quote - "could destroy the channel tunnel" - Yes, but the difference there - and it is vitally important imho - is that people there have the choice about the risks involved. That is why I wouldn't ban smoking, boxing or rally driving.