Live webchat with Professor Paddy Regan, nuclear physicist, tonight, 21 Mar, 8-9pm

[GeraldineMumsnet]

We're very pleased that Paddy Regan, professor of physics at the University of Surrey in Guildford, is our webchat guest this evening between 8pm and 9pm.

In the wake of the Fukushima crisis in Japan, you asked on this thread if we could get a nuclear physicist on. So thanks to Prof Regan for agreeing to come on to MN.

He's a Fellow of the Institute of Physics, and holds visiting researcher and teaching positions at Yale University and the University of Notre Dame.

He's interested in measurements of naturally occurring radioactive materials (NORM) in the environment using gamma-ray spectroscopic techniques.

In his 'spare' time, he says he plays a poor game of squash, even worse golf and tries to do the occasional sponsored run for the Mental Health Charity MIND. He is married to Susie, a nurse, and they have four children.

[KurriKurri]

Hello Prof. Regan, welcome to MN

I'm asking a question on behalf of my DH (who isn't registered )

He'd like to know if all the reactors at Fukushima have the same cores. And if not are any more dangerous than others?

[GeraldineMumsnet]

Just been chatting to Prof Regan - he had to dash back to his office to do the webchat because his internet at home been changed today. We know those sorts of days!

So thanks to him for dashing, and for coming on tonight.

And thanks to everyone who has posted a question.

[PaddyRegan]

@CuppaTeaJanice

Welcome to Mumsnet!!

From the mists of my memories of physics lessons 20 years ago at school, I vaguely remember that there were three types of radiation - two types were particle based and were relatively simple to protect yourself from, and the third was more like a sound wave which could penetrate most materials except a thick layer of lead(?)

Please could you explain the different types of radiation simply, and also explain which form of radiation the people near Fukushima are at risk from and whether it will be relatively easy for them to protect themselves, or is it inevitable that if they are in the area they will be affected?

Hi there,
I think you mean alpha, beta and gamma radiation. Basically alphas and beta particles are 'particulate radiation' and gamma-rays are a form of light which is too hugh in frequency for our eyes to pick it out. They all have different properties, but alphas and betas can do quite a lot of biological damage, but only if they are in contact with the body. This is why you sometimes see the guys in suits and breathing aparatus, these are to stop alpha and beta particles being breathed in etc. Gamma rays are like X-rays at the hospitak. They can do some biological harm and travel further through air. The main radiation risk for the workers at Fukushima would be exposure to 'whole body gamma doses' which they can reduce by getting further away from the radioactivity sources are they arrive. Thick metal/ materials will stop gammas, a piece of paper will stop alphas and a thicker piece of paper will stop beta particles.

[PaddyRegan]

hi everyone, I will do my best to get through the questions as well as I can. Emails for later questions can be found at my home page. I'm also on twitter (@Paddy_Regan)...all the best, Paddy

[catinthehat2]

Blimey, he's quick

[catinthehat2]

[PaddyRegan]

@LeninGrad

I read recently that 29,000 Americans will develop cancer as a direct result of radiation exposure from CT scans, and that is thought to be an underestimate. That can't be right can it? No-one warns you of that risk when having a procedure like this.

This sounds about right to me...but it has to be taken into the context of the number of people who have cancer every year anyway (in the UK the lifetime risk of death from cancer is around 25% across the population...25% of americans is ~75 million people across their lifetimes, so we might estimate a rough death rate from cancer in the US per year of 1 million a year. The CT scans might be used in the treatment of people who are ill anyway....as with all such statistics, the numbers have to be taken int context.

[PaddyRegan]

@catinthehat2

Blimey, he's quick

i'll take that as a compliment....

[TheSkiingGardener]

Good evening.

How accurate and reliable do you feel the information released by the Japanese authorities is? Are the readings reported by outside soured and the levels being found in plant matter consistent with the information given?

And finally, how optimistic are you that the situation will be resolved without further escalation.

Thank you

[ThisIsANiceCage]

Not a Q, just wanted to say thank you to Prof Regan for going to all this trouble for us.

And without even the lure of a Mumsnet !

[HereMeRoar]

Hello

Why do the authorities keep insisting that even in a worst case scenario lots of lives won't be at risk and the worst that can happen is local contamination? Is this right? Why no (even remotely possile) potential wider threat?

Thank you

[Indelible]

Do you think there is a future for thorium reactors?

[ObscureReference]

OMG a nuclear physicist!!



Ahem.... Hi! :)

I had heard that they were flooding the reactors with sea water to cool them and that this would cripple them, rendering them forever useless, but now there are reports that they are trying to 'fix' them? Any chance you could clear up this discrepancy?

I would ask a more intelligent question, but others MN'ers have got there before me!

BTW, How's the Cat?

[brightpurplecow]

Hi Professor, thanks for taking the time

Just wondered what you thought about Germany's reaction to the Fukushima crisis - is this a massive overreaction or should we be taking a similar stance?

Thanks!

Katharine

[MrsKwazii]

What is your view on the reporting of the Fukushima nuclear situation so far? In Germany, people were apparently stocking up on iodene tablets and geiger counters - do you thin that the media is irresponsible when it comes to nuclear?

[PaddyRegan]

@TheSkiingGardener

Good evening.

How accurate and reliable do you feel the information released by the Japanese authorities is? Are the readings reported by outside soured and the levels being found in plant matter consistent with the information given?

And finally, how optimistic are you that the situation will be resolved without further escalation.

Thank you

i think that they are giving us the correct information. it is impossible to hide a radiation leak as we can measure the fingerpint radiation from many different places. I am also optimistic that, as long as they can keep getting the water in to cool the plant down, there will be no further escalation.

[MrsKwazii]

Just wanted to add that the German media info came from MmeLindt's v good blog ladouceviesuisse.blogspot.com/

[PaddyRegan]

@ThisIsANiceCage

Not a Q, just wanted to say thank you to Prof Regan for going to all this trouble for us.

And without even the lure of a Mumsnet !

thanks...i also have a mum you know!!
p.s. where is my biscuit?

[PaddyRegan]

@HereMeRoar

Hello

Why do the authorities keep insisting that even in a worst case scenario lots of lives won't be at risk and the worst that can happen is local contamination? Is this right? Why no (even remotely possile) potential wider threat?

Thank you

again this is to do with numbers and rates. The 'worst case scenario' that we are always asked about would be a full nuclear meltdown. (This has not happened, but some of the fuel rods have been compromised and radioactivity released in the pressure vessels). Even with this 'worst case scenario' it is physically impossible for this to develop into a nuclear explosion for all sorts of physics reasons including (a) the control rods went in as soon as the earthquake came so no more fission production from that point on and (b) the enrichment of the fuel into the sort you need to make a nuclear explosion (i.e. like a nuclear weapon) is not sufficient...(it never is in a reactor).

[PaddyRegan]

@Indelible

Do you think there is a future for thorium reactors?

yes, very much so, in particular in India (1 billion people all who need power and lots of thorium). There are a few technical issues (such as the need for a plutonium or 235U blanket needed to 'fire the reactor up' but it has many advantages in terms nuclear proliferation fears (i.e., you can really used it covertly to make nuclear fuel for a weapon etc.)...i think (personally), that at least in India, these are the future.

[PaddyRegan]

@ObscureReference

OMG a nuclear physicist!!



Ahem.... Hi! :)

I had heard that they were flooding the reactors with sea water to cool them and that this would cripple them, rendering them forever useless, but now there are reports that they are trying to 'fix' them? Any chance you could clear up this discrepancy?

I would ask a more intelligent question, but others MN'ers have got there before me!

BTW, How's the Cat?

The sea water was used as it was 'handy' when they needed it. Not all the reactors were flooded with sea water (4-6 were out of use at the time anyway). i think that 'fixing them' refers to the cooling systems that should have kicked in following the earthquake (i.e. pumping regular water around using an electrical generator to cool the cores.) The reactors with damaged fuels rods in the core are basically not useable for power generation anymore...for a start the outer building walls are missing.

[catinthehat2]

"you can really used it covertly to make nuclear fuel for a weapon etc"

can???
or do you mean can't?

[PaddyRegan]

@brightpurplecow

Hi Professor, thanks for taking the time

Just wondered what you thought about Germany's reaction to the Fukushima crisis - is this a massive overreaction or should we be taking a similar stance?

Thanks!

Katharine

I personally think it's an overeaction and more based on the fact that there are important local elections coming up in germany and the green party there often hold a sway in power. Nuclear in germany is still controversial, i think as a follow on from its position as the 'border state' during the cold war....but again, just my personal view.