Posts Tagged ‘nuclear power’

Why don't nuclear reactors go kaboom? A reactor kinetics primer part - 3

Sunday, January 27th, 2013

Water Dolphin

We have discussed the time behavior of the neutron flux and reactivity feedbacks. Now it is time for the the thermal side of things. The point kinetics model describes how much energy is produced in the fuel, but we also need a model for how the energy is transported within the fuel, through the fuel cladding and into the coolant. To figure it out we need models for heat conduction through the fuel and cladding, heat transfer to the fluid through convection, properties of the fluid at different temperatures and pressures and so on. This blog post will deal with the heat conduction in the pellet and through the cladding.

(more...)

Why don't nuclear reactors go kaboom? A reactor kinetics primer part - 1

Monday, January 7th, 2013

Nuclear reactors contain tons of fissile material and nuclear bombs contain only kilograms of fissile materials, so why does one of them explode with enough force to flatten a city but the other doesn't? I will pull out some latex skillz and geek it out with equations to describe the physics behind whats in nuclear engineering is called reactivity excursions or RIA (Reactivity Insertion Accident). The level of these blog posts will be such that an interested and fairly math savy person can understand and calculate these kind of things on their own.

Castle Romeo photo: United States Department of Energy, Source: Wikimedia

(more...)

Nuclear news

Sunday, December 9th, 2012
Together they are giving a picture that Russia is really beginning to go all in for nuclear. Of course Russia has always been a pioneer in the nuclear field, but despite that they "only" have 33 reactors running producing less than 18% of electricity.

 

Taken from the IAEA PRIS database

(more...)

Some good videos with Bill Gates

Tuesday, May 15th, 2012

Bill Gates has fully realized the potential of nuclear and he has spoken often and a lot on the issue. Here are a few videos that are well worth watching.

The Gate Notes: Nuclear Energy after Fukushima (click on the link, video can not be embedded here)

The Gate Notes: An Energy Briefing with Daniel Yergin: Nuclear Energy

And here are two videos embedded. (more...)

Did the Japanese authorities lie about the Fukushima accident? Part 1.

Wednesday, May 2nd, 2012

A powerpoint presentation made by professor Majia Holmer Nadesan is getting some attention around the web, in the presentation she claims that the Japanese authorities, among others, lied and covered up information about the Fukushima accident. So let's have a look at it.

(more...)

Why I do not trust "We don't need nuclear" rethorics

Thursday, May 5th, 2011

Dear Mr./Ms. Anti-Nuclear Activist... for decades You have been telling me "It's easy to get off nuclear, if we just want to!". Well, alot more powerful people than You have made similar promises...

Where do we stand today after all these promises? Pretty much exactly where we were 5-10-20-40 years ago.

So - dear Mr./Ms. Anti-Nuclear Activist - You promise me gold and green forests... but You don't deliver. Maybe this wasn't Your fault. Maybe You'd like to blame Big Oil or lazy politicians or a public that just won't see things the way You do. It's allright... You can try to shift the blame any place You want. But it doesn't matter whose fault it is, becasue assigning blame does not alleviate the problem.

So when You - dear Mr./Ms. Anti-Nuclear Activist - today, yet again, try to tell me it's allright to renounce nuclear power, it means I cannot trust You, because things might no go they way You promise me they will.

What will You - dear Mr./Ms. Anti-Nuclear Activist - need to do to gain my trust again?

Well it's easy: get the replacements up and running. Get full replacements for fossil fuels and nuclear power up and running, hooked to the grids and pumping GigaWatthours of energy into them, and I'll trust You again.

So... dear Mr./Ms. Anti-Nuclear Activist.... get to work. We're eagerly waiting for You.

Oh... and one last thing: while we wait for you to get this work done, You do not get to say we cannot make any new nuclear power if we want to, at least on the "We're not gonna need it in a while"-argument alone.  Just saying this FYI...

German economy minister: "To prevent paper cuts, we must cut off our arms"

Friday, April 15th, 2011

Ok, now it is official: Germany has gone batshit crazy.

Power firms should invest massively in coal and gas-fired power technology and renewable energy sources, Harry Voigtsberger, economy minister of Germany's most populous state North Rhine Westphalia, said in the Financial Times Deutschland.

The original article can be read here (in german).

Angela Markel seems to be agreeing...

In a document from Friday's meeting obtained by Reuters, Merkel and her ministers laid out a six-point plan that includes a 5 billion-euro credit programme to support renewables.

It will also require building new gas and coal plants, Merkel said. "Gas and coal power plants were discussed... an accelerated exit from nuclear energy will lead to replacement power stations," she said.

Why? So they can get rid of nuclear power...

This is about as stupid an idea as to say that in order to prevent paper cuts to your finger you should cut off your arms!

Sure... you achieve what you aimed for... but did you really concider the side effects before you took a knife and started carving?

Diese dummen Deutschen...

George Monbiot: "...the anti-nuclear lobby has misled us all"

Wednesday, April 6th, 2011

George Monbiot, environmentalist and journalist... and once a strong opponent to nuclear power has faced an "unpalatable truth": the anti-nuclear lobby lied to us.

http://www.guardian.co.uk/commentisfree/2011/apr/05/anti-nuclear-lobby-misled-world

The article is only about 30 years overdue... but I cannot stop smiling when I read this. Monbiot did what everyone should do: check the facts, think for yourself, dare to think you may have been either right or wrong.

The unpalatable truth is that the anti-nuclear lobby has misled us all

I've discovered that when the facts don't suit them, the movement resorts to the follies of cover-up they usually denounce

George Monbiot

Over the last fortnight I've made a deeply troubling discovery. The anti-nuclear movement to which I once belonged has misled the world about the impacts of radiation on human health. The claims we have made are ungrounded in science, unsupportable when challenged, and wildly wrong. We have done other people, and ourselves, a terrible disservice.

Thank yo so much for this George. Along with Mark Lynas and Patrick Moore, you have shown that "green" does not have to mean "unscientific zeal".

A litte riddle... solve it and win pins.

Friday, April 1st, 2011

This is not so much an April Fools joke as it is a little riddle. It connects to a current event... and to things that happened in the last century. And of course it has something to do with nuclear power.

What are these equations?

What are these equations?

This is a comparison between two estimated values... what are they?

Update: we have a winner! Tony scored a perfect bullseye. I'm quoting him here:

‘a’ is the number of iodine atoms that would fill the known universe, if the iodine were at ‘normal’ temperature/pressure.

the second number is the number of radioactive iodine atoms you would have needed, when Chernobyl exploded, in order to have one radioactive iodine atom left today.

An added trivia is that the estimated number of atoms in the known universe is approximately 10^80.

The upshot of all this is this: there is not a single atom of Iodine-131 released by Chernobyl in existence today. The last atom decayed in no more than 4 years after the accident.

/Michael

Day fifteen after the tsunami

Saturday, March 26th, 2011

Update 15:00(UTC)/16:00(CET)/00:00(JST)

NISA has released their update, link 1, link 2, link 3. I have also reattached the earlier JAIF figures at the bottom of the last update to see if it will fix the bug that gives an error when one clicks on the pictures.

As usual the NISA figures are between (). The NISA data is 3 hours older than the JAIF data.

 

Reactor 1:
Water level in the core: 1.65(1.65)  meters below the top of fuel assemblies
Flow rate of injected water: 7.2 cubic meters per hour
Core pressure: 476 (477) kPa
Containment pressure: 270 (270) kPa *note, in the last update I misstakenly wrote 370 kPa as containment pressure.
Core temperature(feedwater nozzle): 195.3 Celsius
Core temperature(bottom head) 146.3 Celsius
Dose rate within containment: 35.1 Sv/hour

Reactor 2:
Water level in the core: 1.1 (1.1)  meters below the top of fuel assemblies
Flow rate of injected water: 18.6 cubic meters per hour
Core pressure: unknown
Containment pressure: 116 (115) kPa
Core temperature(feedwater nozzle): 107 Celcius
Core temperature(bottom head): 100 Celsius
Dose rate within containment:  43.4 Sv/hour
Spent fuel pool temperature:  57 Celsius

Reactor 3:
Water level in the core: 2.3  meters below the top of fuel assemblies
Flow rate of injected water: 14.5 cubic meters per hour
Core pressure: 139 (139) kPa *note, I wrote the wrong pressure in the last update
Containment pressure: 106.6 (106.6) kPa
Core temperature(feedwater nozzle): 37.6 Celsius (sounds like an error on equipment)
Core temperature(bottom head): 106.1 Celsius
Dose rate within containment:  36.1 Sv/hour

Due to my error with containment pressure in the last update I withdraw my speculation that its hard to control the pressure in number 1. Rather it seems like the situation is fairly stable. Otherwise not much new information.

The US Department of Energy has done some arial surveys around Fukushima Daiichi and released the data. I have one pictures from it below(hats of to http://neutroneconomy.blogspot.com/ where I found the pictures). The dose rate unit used on the picture is millirad. 1 millirad=10 microgray =* 10 microsievert
*that equality between gray and sievert is only valid for gamma radiation. Gray measures the energy deposited while sievert is weighted in such a way that it expresses a cancer risk.  For gamma the weighting factor is 1.

Update 12:00(UTC)/13:00(CET)/21:00(JST)

No NISA updates have been released yet today, JAIF has released their update as usual(one hour old as of writing this).

Reactor 1:
Water level in the core: 1.65  meters below the top of fuel assemblies
Core pressure: 476 kPa
Containment pressure: 370 kPa
Core temperature(feedwater nozzle): no new data
Core temperature(bottom head) no new data
Dose rate within containment:  no new data

Reactor 2:
Water level in the core: 1.1  meters below the top of fuel assemblies
Core pressure: unknown
Containment pressure: 116 kPa
Core temperature(feedwater nozzle): no new data
Core temperature(bottom head) no new data
Dose rate within containment:  no new data

Reactor 3:
Water level in the core: 2.3  meters below the top of fuel assemblies
Core pressure: 202 kPa
Containment pressure: 106.6 kPa
Core temperature(feedwater nozzle): no new data
Core temperature(bottom head) no new data
Dose rate within containment:  no new data

All 3 reactors are now cooled with freshwater instead of sea water. It seems hard for them to get the pressure in the number one reactor under complete control. In JAIF's written update they say lights are on in all control rooms now. Levels of radioactive materials in the seawater around the plant is climbing. TEPCO is releasing updates on activity in both sea and air, I have attached levels as pictures in the bottom of this update.

The ground deposits of I-131 the prefectures around Fukushima ranges from less than 1 to 16 kBq per square meter. The cesium ground deposits ranges from less than 0.1 to 1.9 kBq per square meter(here are the last 3 MEXT updates on ground deposts link 1link 2link 3). The data form the worst effected prefectures are however omitted, we hope MEXT will make those figures available asap! As a comparison the ground deposits of cesium due to Chernobyl ranged from a couple of hundreds to a couple of thousand kBq per square meter.

 

Update, March 26, 12:00 (UTC) / 13:00 (CET) / 21:00 (JST)

Not much to add today. The radiation levels in the sea outside Fukushima I are sky-high. The long term effects are hard to predict now since a sea contamination is entirly different from a land contamination, where land is basicly a 2D area, which leads to a thin and high concentration on the surface, and where rains soon concentrate the contamination to "hotspots".  The sea on the other hand is a 3D volume where currents quickly dilute any contaminant by dispersing them over very wide areas.

The JAIF updates from 10:00, 16:00 and 21:00 (JST) for March 26 are pretty much uniform. The big news is that freshwater injection to the cores of 1, 2 and 3 has started as opposed to using salty sea water. Apart from that nothing new. The radiation readings at the main gate (1 km out) has stayed at 170 μSv/h all day. The west gate read 147 μSv/h at 13:30.

NISA has not said anything new since last night.

 

Links(english):
BBC We should stop running away from radiation
Hufftington post US brings fresh water to japan nuclear plant
NY Times Japan presses nuclear plant repair as more damage is found
Rod Adams Shaken, flooded, stressed by power outages, Fukushima Daiichi moves into second place
The Independent Fear and devastation on the road to Japan's nuclear disaster zone

Links(swedish):
Röda berget
Dr Angels blog
DN Radioaktivt jod tusen gånger tillåten nivå i havet
Aftonbladet Strålningen ökar runt Fukushima
SvD Radioaktivt vatten i reaktorer
Tänkvärt? Eller inte!
Grön horizont