cwamit..... Interesting blog trying to put peoples fears at rest but read ALL the blog not just the explanation.

http://morgsatlarge.wordpress.com/2011/03/13/why-i-am-not-worried-about-japans-nuclear-reactors/

There is question on the qualifications of the person that wrote the article.....

"My critical thinking antennae raised at the beginning of this post. First, the disclaimer, which says clearly we should not hold the poster responsible for the content. Then we are introduced to Dr. Oehmen, but not given any concrete connection between the poster (Morgsatlarge) and the Doctor. Then there is the matter of the "PhD Scientist". No such thing. Perhaps, though, Morgsatlarge is not a native English speaker.

Google confirms there is an Oehman at MIT, but the top kit points toward research on food in the UK. "

"I found a slightly different J. Oehmen, one who wrote his PhD dissertation on supply chain management.

Therefore I doubt his article is more reliable than a text from me about the technical side of nuclear power would be. I'm an economist."

It seems written by a food researcher with a PhD in supply chain management !!!
I feel so much safer now NOT

I wouldn't profess to be an expert, but I did spend about 18 months designing modifications to various nuclear power plants and nuclear dockyard installations in the UK to withstand seismic activities.

At the time the UKAEA had a clamp down and wouldn't renew licences unless the owners could prove the plant would be safe in a seismic event.

All the owners wanted to do was to control the reaction (drop the fuel rods in) and cool the reactor. They thought the risk was not worth the expense of ensuring operation capability during or after any event. The cooling rate didn't matter, so long the temperatures and pressures generated were below ultimate yeild.

In all the UK plants I worked on the rods sat within casings and were held up with power, so any power loss or press any button and the rods slid down automatically with gravity in thier casings. I never found out if they could be forced down or just fell with gravity.

All the experts I spoke to told me that in reality the natural circulation of the coolant (water or gas) would cool the heat generated post rods dropping without the need for the pumps, coolers or evaporator to run. Not sure this was true as they obviuosly couldn't prove it to the UKAEA and so most of my work was ensuring the cooling pumps and pipes were OK during a quake. They had 3 backups for everything, so 3 lots of work.

Also the reactor chamber has a few other penetrations through it, and you had to ensure the integrity of them as well, but not their operability. failure of them would have been minor radiation leak, nothing serious.

One issue was UK reactors were generally built near lots of cooling water (the sea) a long way from built up areas. Hence they tended to end up on old esturaries with gravels beneath them. Natural frequency of earthquakes are low, but so also is the resonance frequency of floppy gravel beds with massive heavy blobs of reactors on top of them. Bit like a brick on a soft spring. So unfortunately the peak accelerations the structures were subjected to had the potential to be amplified by resonance of the ground.

Can't recall the peak accelarations they were designed to but I think it was something like 1.2G upwards (so 1.2 x its own weight going up) and 3G sideways, in various configurations.

How these relate to Richter scale is very difficult to generalise as it depends on how the earth and the structure behaves, but I suspect there are a fair few people right about now looking at the Japanese accelerometers on the power plants and rewriting the design codes.

As an aside a person living in a house on Dartmoor, in the southwest of the UK,. received about 1,000 times more radiation each year through natural radon gas in the granite rocks than a nuclear plant worker was permitted to receive under H&S law. It gets worse each year as people get better sealed and centrally heated homes.

A nuclear worker who lived on Dartmoor and took his radiation monitor home with him for 1 day could get the next 12 months off work. So could a worker who placed his glow in the dark (luminescent) watch face next to his monitor for a couple of days. Hence the reason you weren't allow to wear luminescent watches or take your monitors home.

oliver said...


(.)(.) I think you are the fifth funniest guy I know

Who is your seventh?

40 years old ? Reason is public nuclear phobia and no new nuclear plants are build from years in western countries.
That mean less progress, less technological advance. Imagine car that is 40 years old and compare to modern one.
Maybe nuclear plants should be build in Australia and electric power sent to Japan by undersea cable?

just seen a bus on top of hospital building 3 or 4 stories hight..............this wave is just getting bigger

Those waves are nice and offshore, would have been great to ride

Carantoc said...

And ...

if a mechanic dropped a spanner on his foot whilst fixing a car that had broken down inside the perimeter of the reactor hall it was classified as a nuclear accident.

going by that reasoning, the work you did to withstand siesmic activities was probably curb and gutter or reseal the car park

I've been watching news footage today. Holly F !

I was chatting off line about freeride equipment with one of our Japanese members last week. He hasn't been on since Friday. I hope you are okay Paul.

www.seabreeze.com.au/Members/Profile/Details.aspx?member=pm01537

Not too flash I would imagine.

I never understood that much about them. I am certainly no expert and it was a long time ago.

The thing with the UK reactors was that everyone told me the pumps didn't need to run to cool them once the rods were dropped in and the chain reaction was stopped. The natural circulation of coolant from getting hot, rising, cooling, falling was enough to circulate it and to remove heat.

But - given they couldn't prove this to the UKAEA and had to spend lots of money ensuring the pumps worked always had me a bit sceptical.

Also I guess that only applies if the coolant system remains intact and able to hold pressure. If it fractures presuambly all the coolant escapes, then it becomes air cooled and blows up.

The coolant system was more like a heat exchanger than direct cooling. The reactor gases got hot and were cooled with water or gas through a heat exchanger, the hot coolant used to drive trubine to produce power.


I think the reason they all told me the pumps didn't need to run was because Chernobyl blew up and they were pointing out that unlike chernobyl the rods drop with any system failure (they don't have to be forced down) and the coolant system requires no input to function ((it doesn't need to be pumped).

I am sure it was more PR on me - or PR on themselves trying to convince themselves that a similar thing couldn't happen to them.

latedropeddy said...

hope these guys made it.

just watching that video, those huge wave are reforming within meters of bashing through a seawall, that all seems to be going on inside a harbour

felixdcat said...

Gizmo said...

So do the people on the forum saying that nuclear is safe want to reconfirm their thoughts... yet?

And then how is the mess to be cleaned up?.... Hire some Mini Skips and Jim's Bobcats!!

And all the pro nuclear ppl could come out of lala land and lend a hand driving the bobcats!............. Or maybe they would be too scared to close to a safe , non polluting energy power plant

FFS how many sky scrapers fell down?. Good engineering and strict Government regulations saved hundreds and thousands of lives in japan. Who would be stupid enough to think that the next nuke plant the Japanese build won't be next to invincible.

Nuclear power is a necessary risk if we want 7 billion people on the planet. Man up anti-nuke cowards.

Einstein can't be classed as witless.
He claimed atoms were the littlest.
When you did a bit of splitting-em-ness
Frighten everybody s***less
- Ian Dury

barn said...

Nuclear power is a necessary risk if we want 7 billion people on the planet. Man up anti-nuke cowards.

Let's build Australia's first nuke facility in Buli, NSW.

anybody want to buy some shares in my little Uranium exploration company, weve got 4 really prospective leases and the share price is looking really affordable at the moment

oliver said...

barn said...

Nuclear power is a necessary risk if we want 7 billion people on the planet. Man up anti-nuke cowards.

Let's build Australia's first nuke facility in Buli, NSW.

Well if you would stalk me some more you would realise Bulli is not big enough for a Nuke facility. It would make more sense to put it in outback NSW.

But I'm all for it, considering the long wall mining going on under here that is draining our drinking water, were gunna need that Nuke plant to run the De-sal plant.