10 differences of the RBMK and a PWR

Since it was 30 years since the Chernobyl accident on Tuesday, I was thinking it would be a good idea with 10 facts related to that as a little "comeback" of Friday Facts (so sorry that I don't manage to make these facts every week, it's just that lately I've either been travelling, or really busy with my PhD, which I sort of have to prioritize sometimes ;) ). Or, not just ten facts, but ten differences between the Chernobyl type RBMK reactor ("reaktor bolshoy moshchnosty kanalny", meaning high-power channel reactor), and the standard pressurized water reactor (PWR). 

Ready? 

Let's go!

1. PWR is the most common type of reactor in the world operated in countries like USA,  Belgium, Brazil, China, Finland, France, Germany, India, Japan (the Fuksuhima reactor was not a PWR, though), Russia, Spain, and Sweden, and several more. The RBMK was a Soviet develloped design - only built in the former Soviet Union.
2. the PWR uses water as both moderator (for slowing down all the neutrons from really high energies, to really low energy - which is what we want <3 ) and as cooling medium, but the RBMK uses graphite as moderator, and water as cooling medium. Normally we say that the PWR is light water (light water is what we normally just call "water", instead of heavy water) moderated and cooled, and the RBMK is graphite moderated and light water cooled.
3. the RBMK was designed with a positive void coefficient; I'll don't go in detail on that now (if you want me to, I can make a separate blogpost about what this means), but in short it is the reason why the RBMK is unstable under certain conditions
4. the tip of the control rods of the RBMK actually didn't control the reactor/absorb the neutrons -it was made out of graphite that speeds up the fission process, instead of a material that actually shuts it down
5. the control rods of the RBMK could be withdrawn completely from the reactor - even if it wasn't allowed (no one should EVER be able to overrun safety systems, like it was done the night of the accident)
6. it took almost half a minute to insert the control rods into the RBMK reactor; on a PWR it takes around a second or so
7. a PWR needs fuel which is enriched to 5% uranium-235, but the RBMK only needed 2% - so it was economical with the fuel
8. the RBMK could have its fuel changed while it was running. This, together with the low enrichment (no 7) made it ideal as a producer of weapons plutonium 
9. a PWR is passively safe, but the RBMK definitely wasn't
10. the Chernobyl reactor didn't have any outer barrier; meaning the reactor was placed more or less in a warehouse rather than a full containment building. Therefore, when the reactor actually exploded, the radioactive inside of it could get out, and fresh air (oxygen...!) could get in, making a strong fire that lasted for days

These are just the first ten big differences I could think of, but there are even more. 

When I, or other nuclear scientists, say that Chernobyl could never happen in a modern, Western reactor, it's not because we just don't want to see reality or something silly like that, but it's because of these facts listet above - which makes that accident physically impossible in, for example a PWR...!

testing of reactor grade concrete - the concrete stays intact, as the plane is just disintegrated (plane vs concrete: plane 0, concrete 1)

PS: There are still some RBMKs operating in the world today, but major modifications have been made to these reactors.

Not a good night...

the experiment is behind this thick, blue door (just before the migraine)

I had such plans for last night! I had the evening shift at the cyclotron, and in addition to baby sit the experiment, I was planning to answer a lot of e-mails, prepare for my teaching today, work on my  gammas from fission results, and I had planned to make a long blogpost about Chernobyl.

Then I got a migraine, and could just barely be at the lab, and didn't get to do anything at all! Luckily the cyclotron was behaving, so it was an easy shift, and I could even get an hour sleep - the only thing that helps.

The annoying thing is that now, even though the pain is gone, I'm really exhausted - wish I could just stay here in bed and sleep for a couple of hours, but I'm teaching the nuclear physics students about thorium and nuclear energy in a couple of hours, and I din't at all get to prepare my teaching yesterday. Meaning I have to do it now. 

Well well, hoping I'll feel better very soon (*poof* away with exhaustion...!), and hope you all will have a productive and good day!

If all goes as planned, I guess my todo list look something like this:

1. prepare teaching
2. answer e-mails
3. teach
4. work with TALYS - where to go next...?
5. make figures of gammas, gather them and send them to supervisor Jon
6. (start preparing for PhD day???)
7. work out (which I'm not particularly fond of, but I want my body to last for 70 more years, and then there's no getting around going to the gym)

"Chernobyl equals 100 Hiroshima bombs..." (foredrag)

"Radiation and reason" by Wade Allison

So tonight I'm preparing for a talk I'm going to give at Kongsberg Library tomorrow, which is the day that marks the 30 years anniversary for the tragic accident in the nuclear power plant in Chernobyl, and I feel like I need to address some of the myths and misconceptions about the accident and its consequences. The statement in the title of this blogpost is one of these myths, and it's of course NOT true. 

CHERNOBYL DID NOT EQUAL 100 HIROSHIMA BOMBS!

The thing is that this statement comes from someone (only) looking at the release of one isotope of caesium, and then comparing how much of this isotope was released in the Hiroshima atomic bomb explosion, and how much was released in Chernobyl. It is true that the release of one particular isotope was 100 times bigger from Chernobyl than from the Hiroshima bomb, but that tells us more or less zero... 

The reason why there was a bigger release of caesium from Chernobyl was that even tough the source of energy is fission in both a nuclear power plant and an atomic bomb, the fission process isn't exactly the same: the atomic nucleus is divided in different ways in those two, and you don't get the same fission products (caesium isotopes are some of them) from a nuclear power plant versus a bomb. (Remember, there was no nuclear explosion in the Chernobyl reactor - the radioactive release came from the normal operation.)

You do get caesium in both fission processes, but the amount of the different isotopes is different, and there's no problem finding certain isotopes that were released in much higher quanta in the Chernobyl accident than the Hiroshima bombing (like caesium).

What does this tell us?

Nothing, really.

The only thing it might tell us something about is that caesium is produced in different quanta in an explosion versus a power plant.

What does this saying makes us feel or think?
It makes us scared.

It makes us instantly think that Chernobyl was 100 times worse that the Hiroshima bomb. The accident was bad, but it doesn't even come close to dropping an atomic bomb on a city...!

What really kills in a nuclear explosion/atomic bomb is the extreme release of force, and not the radioactivity - believe it or not. The release of one specific caesium isotope from Hiroshima actually isn't particularly interesting. And the fact that there was a release of one certain type of caesium that was 100 times greater in the Chernobyl accident than the Hiroshima bombing does not tell us that Chernobyl was like 100 Hirsohima bombs!

Quote from this interesting article with five facts about nuclear power plants:

There's no getting around it: Chernobyl was awful. The design of the reactor was terrible, its purpose for being was terrible, its operation was terrible, the test they were performing when it blew up was terrible. The reactor was designed to primarily produce plutonium for nuclear weapons. The reactor was housed in a warehouse rather than a full containment building. It was designed so overheating sped up the reaction until the whole thing burst like an overinflated balloon. But we don't have to fear nuclear energy just because the Soviets did it the dumb way. That would be like banning cars because some drunk guy crashed one while trying to steer with his penis.

PS: I'm going to be a guest on Tidenes Morgen on P13 tomorrow morning around 8 AM, it will not be about the Chernobyl accident, but maybe it'll be fun to listen to :)

Grandmothers of Chernobyl

On Tuesday it's 30 years since the tragic accident at the Chernobyl nuclear power plant, and I see all kinds of articles and films and talks about the accident popping up on Facebook (and basically all over the internet) these days. Not so strange, really.

A friend of mine posted this video of "The Moonshine Grandmothers of Chernobyl", about old women living inside the exclusion zone in Chernobyl, that I really think you should watch :) (Click on the link just below the picture.)

https://www.facebook.com/AJWitness/videos/10156797667900557/?pnref=story

It's soon time for bed here in Rose-castle - we have a busy week in front of us, where I'm giving a talk about the Chernobyl accident at the library in Kongsberg, being a guest on "Tidenes Morgen" (P13), going to a funeral (unfortunately), and of course trying to work hard on my research - time flies, and by the end of this year there is no more money coming my way from the University anymore... 

Plan for tomorrow: get up super early, get Alexandra to kindergarden, work on Tuesday's talk, go to funeral, more preparation of talk, get home, work out, sleep...

Hope you all have had a great weekend!

See you tomorrow :)

One last "natural" post

So I was on the radio this morning (Kulturnytt - you can hear it here), and one thing that Berit made a point of was "natural carrots" versus "un-natural beta-carotene": In a study someone had isolated beta-carotene (that you find in carrots), and seen that it actually may increase the risk of getting some types of cancer (I haven't read the study, so don't take this as a warning - I have no idea of how big this risk increase is supposed to be, or how much you actually had to eat to see this increase, or if the study was even done on people, or what), but eating carrots seems to be healthy...

Well, if you isolate one substance (beta-carotene) from carrots, and this turns out to potentially cause cancer, then the only thing you've shown is that this particular substance cause cancer. And that there is an element in carrots that may be bad for you.

You have not shown that carrots are healthy because they're natural, and you have NOT shown that beta-carotene is bad because it was made in a lab! 

Maybe carrots are made of other substances than just beta-carotene...? 

These other substances may either neutralisze the negative effects of beta-carotene in some way, or the positive effects from the other substances may turn out to be so much better than the negative effects from the beta-carotene, so that all in all the effect is positive. But it's NOT because carrots are natural!

Someone critized me for my first blogpost about this subject, since no-one is talking about eating uranium. Ok, here are two other examples of something that people actually may eat: 

European destroying angel mushroom (Hvit fluesopp in Norwegian) and Cowbane (Selsnepe in Norwegian). Both of these are deadly poisonous!

Even potatoes may be dangerous to eat - if you eat potatoes that have become green you may have diarrhea, cramps, or you can even die (rare!)...

So again; please just stop using "natural" as a justification of why something is good, or that stuff that's made in a lab is bad!

2 years since we met...and happy birthday!

Yesterday it was two years since I was sitting alone in my office at Science Library; it was the middle of Easter, and was making my last preparations for the talk I was going to give later that day, in Hamar, at "The Gathering (TG) 2014".

As aI often do, I shared a couple of pictures on Instagram and Facebook...

...and suddenly I got a message from a guy…

I had never really talked to him before, but since I didn’t know anyone in Hamar, I was just happy to have someone to meet for a coffee, maybe eat something, maybe have a beer with.

In the middle of my talk I saw a new person in the audience, and I guessed it was Anders, and after I had finished on stage we started talking. And we talked. Ate pizza, drank beer. Shared a bottle of wine. And we talked, and we talked. And shared another bottle of wine.

There were never any coffee, but we talked for 12 hours straight  (a lot about physics, obviously, and especially about torque…:P), and somewhere between the beginning of the first bottle of wine and the end of the second, he kissed me.

I didn’t at all think that Anders was going to be the man of my dreams (it took me several months to realise); I thought he was too young, too much of a student, and too geeky. There were ups and downs from that first meeting in April until the end of December that year. First Anders was more into me than I was into him, and then it was the other way around, and then it was all a big mess!

For a long time I thought we would never happen…

it was the best of times, it was the worst of times

For some reason, something happened in January 2015, and finally we were at the same place at the same time. The emotional roller coaster ended, and we became a couple. We went on our first vacation...

...and just after we came back home from Barcelona, Anders moved in with me in Rosecastle <3

It’s so weird to think about how I’ve only known him for 2 years, because it really feels so much longer.

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So yesterday we were out celebrating the two years we've known each other, and today it's your 29th birthday, Anders. I am so grateful you sent those messages, and I am so happy we both figured out we were great for each other! Happy Birthday, I love you <3

after drinking a bottle of bubbles at Champagneria, we decided we were just tipsy enough to go bowling before we went home - perfect evening!

"Natural" (rant) on the radio

Remember this blogpost/rant, about how I hate the word "natural"?

Well, tomorrow I'm going to be on the radio (Kulturnytt), to rant a little bit more about why I think it's silly to use naturality as an argument for anything. Of course, a lot of things that people like to think about as natural are good, but that's not because they are "natural" - like I said in the other blogposts: a lot of things that are 100% "natural" are not at all good for us...

Judging by the first pictures you get from a "natural" google search, water is one of the things that's very "natural". Well, what if I go to the lab and make water from oxygen gas and hydrogen gas? Is there a difference on the water made in the lab or the water you get from nature?

Of course not!

(If you think there's a difference here, you're just missing basic knowledge of chemistry - you should educate yourself, and not go on and on about how "natural" is better.)

What does it even mean? What is "natural", and what is "un-natural"?