Hmmm, just been out for the day and came home expecting a long thread
about this on this ng. Nothing catastrophic seems to have happened
(except that the reactor itself is prolly a write-off), but It's
irritating it has happened at this point, before the new UK nukes were
firmly under construction.
Cue foaming at the mouth, though, by e.g. loonies at the Lib-Dem Spring
"That excessive bail ought not to be required, nor excessive fines imposed,
Really? The BBC reporter on the spot, Damian Grammaticas , has worked for
the them for at least fifteen years so he is hardly lacking experience is
he? It is you that needs to check your facts before spouting rubbish just as
you accuse others of.
And what are his qualifications for reporting anything of a scientific
nature? Just because someone is qualified in English Literature, has a
Diploma in Broadcast Journalism and has spent 15 years travelling the
world doesn't mean that he isn't speculating rather than reporting
facts. Much of the "quality" BBC radio coverage on this subject is
much the same as for other incidents, such as a rail crash, where the
tame "experts" are wheeled in five minutes later to tell us exactly what
has gone wrong. 24 hour rolling news relies on speculation rather than
It seems to me that this is pure hypocrisy on your part. You are doing
exactly what you accuse the BBC of i.e. making statements that are not
supported by facts. In all the reports I saw from the BBC reporters they
made it abundantly clear what had, and more to the point what had not, been
confirmed. The BBC have a very clear policy of reporting things that are
substantiated and saying when confirmation is still required.
There have been two real experts called in, who were in one case
sanguine and factual, and in the second a tad more alarmist.
The rest of the the so called experts have been alarmist speculation.
The story is being covered factually here:
It looks like the reactors are probably toast, but that if they can dump
enough water in to lose the decay heat, they will be able to finally get
the rods out for reprocessing, and decommission them.
Primary and secondary containment seems to be intact: It's the water
circuits and pumps that seem to have failed.
The design pre-dates new PWR types where no pumps are needed in
emergency shut down situations.
Yes, new PWRs are better than 40 year old PWRs. They're still shite though.
They are still relatively fragile technology IMO, the bean counters prefer
them for cost reasons. I prefer the idea of reactors with greater thermal
mass. Where incidents take days or weeks to become an issue.
As do we all. I personally prefer reactors that have to be 'kept alight'
rather than one's that have to be 'damped down'. PWR is a lot better in
this respect than BWR, in that failure in the cooling circuit (provided
the reactor core is fully shut down) doesn't lead to loss of
But its all about cost and development.
They're not even PWRs, they're BWRs. This means (most relevantly) that
there's barely any "containment" worthy of the name anyway. The
primary water circuit goes through the core, and through the turbines
in the turbine hall (i.e. no primary / secondary heat exchanger).
Turbine halls are just too big to make credibly strong as a
containment against a real explosion in the primary circuit, as has
long been done for PWRs and was what saved Three Mile Island from
becoming a disaster.
The large external explosion seen yesterday would have involved a lot
of steam, thus would have involved the primary circuit (there's
nothing else big enough to make that bang). So that means that for at
least one reactor, it's now damaged, and exposed to the atmosphere.
Hopefully the rods themselves are still intact, so the contamination
is only secondary fission products, not fuel.
Yes. They need to keep the rods under water, or they may melt and block
further coolant flow, for several days.
I believe PWR can also maintain enough coolant flow by convection in the
primary circuits as well. Which are so highly pressurised that the water
never boils anyway.
Current reports suggest that the radiation levels in the area, at 1,204
micro sievert, are very similar to those after the Three Mile Island
accident. If that is as bad as it gets after being hit by the sixth
largest earthquake ever recorded, it should serve as an excellent
example of just how safe modern designs are.
Which is why the Priests of Green will be all over it like a rash.
BTW I think Nightjar means milli-sieverts?
Background is about 10mSv IIRC.
"The level of natural background radiation varies depending on location,
and in some areas the level is significantly higher than average.
Such areas include Ramsar in Iran, Guarapari in Brazil, Kerala in
India, the northern Flinders Ranges in Australia and Yangjiang in
China. In Ramsar a peak yearly dose of 260 mSv has been reported
(compared with 0.06 mSv of a Chest radiograph or up to 20 mSv of a CT
scan). The highest levels of natural background radiation recorded in
the world till date is from areas around Ramsar, particularly at
Talesh-Mahalleh which is a very high background radiation area (VHBRA)
having an effective dose equivalent several times in excess of
ICRP-recommended radiation dose limits for radiation workers and up to
200 times greater than normal background levels. "
BTW sieverts represent total dose. Not 'radiation level' as such.
On 13/03/2011 12:32, The Natural Philosopher wrote:
Dose rates are measured in Sieverts/hour.
In the UK, when working with radioactive sources, we set up a
'controlled area' at the 7.5uSV/h point.
Only trained and badged Radiation Workers are permitted inside this cordon.
This value is derived from taking maximum permitted Annual Total Dose (
in Sieverts ) , and assuming an un-classified individual stands at the
boundary during working hours ( iirc ). So any member of the public
would never be exposed to a total annual dose greater than the specified
maximum. There is also 3-monthly max dose limits too, and we set
'investigation' levels if a badged individual exceeds this.
The point being that it's reckoned that 'total dose' is what counts
safety wise, not 'peak exposure'.
If you get a years worth in an hour, (like a CT scan) that's OK ish. As
long as it doesn't happen every day
On 13/03/2011 14:18, The Natural Philosopher wrote:
Just for the record, I should I should probably state that I am the
responsible RPS for a small facility that uses gamma and neutron
sources. It's part of my job to maintain and enforce the Local Rules,
and ensure compliance with the applicable Ionising Radiation and HASS
On 13/03/2011 12:32, The Natural Philosopher wrote:
The report I read said 1204 micro-sieverts. The measurement given in the
follow up reports on Three Mile Island was 100 millirem = 1000
micro-sieverts, which was considered to be insignificant.
1204 milli-sieverts would be a whole different problem.
Yeah, can't expect these new fangled designs to stand up to the worst
disaster in a long time the way the old, proven stuff has. :-/
Looking at the TV and other pictures, it's impressive just how much of
the infrastructure *is* still usable.
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.