2011 Japanese Nuclear Crisis
Click this link
to go straight to the Wind Prediction section, which has a link to the
Finnish Meteorological Institutes's up-to-date and easy-to-view wind
predictions for the next 36 hours.
2011-04-02 Robin Whittle
The earthquake and tsunami have been a
terrible calamity, with the death-toll at in the tens of
thousands and perhaps more. Large parts of some towns and cities
This page, and the related discussion forum
is devoted to providing information about the nuclear crisis,
which currently centres on the damaged reactors Units 1, 2, 3 and
4, in the Fukushima Dai-Ichi
nuclear power plant, (http://en.wikipedia.org/wiki/Fukushima_I_Nuclear_Power_Plant
on the north-east coast of Honshu. Anyone can read the
forum. Anyone with a Google account can join and post
The main English Wikipedia articles which are devoted to this crisis
these pages (see the left of these articles for versions in other
and I suggest these be used as the primary source of information.
material below is intended to support discussions and preparedness in
general - to do things which the Wikipedia page, being encyclopedic and
necessarily fussy about copyright,
Please write to me at firstname.lastname@example.org if you can suggest any
links or images to put here. Please also join and contribute to the
This page is done in a hurry, so its a bit rough. I have no
formal qualifications in any field whatsoever. The information
below is provided free - with a money-back guarantee.
directions. The wind is the primary variable which determines how
many people are exposed to the radiation emitted by the reactors.
|Real time radiation monitors and comparison of various rates of radiation exposure.
|Sites with good technical
|Other substantial discussion
|Understanding this crisis
requires an understanding of the decay heat of the nuclear fuel.
|Photos, diagrams, population
density maps etc.
|Latest developments and a few
|A note that nuclear reactors are
not the only source of radiation - burning coal may release a lot more
than the reactors.
Wind predictions and current observations
The most important thing to watch is wind predictions.
the time the wind is blowing radiation towards you, it will be too late
to leave - too many people will be trying to do the same thing.
Then, the best thing to do is to stay inside, shut the doors and
windows and seal the gaps in them, and any ventilators, with tape,
paper, towels or whatever.
Perhaps the easiest to view of the predictions are the four charts from Finnish Meteorological Institute
This page explains the meaning of the images well. Predictions
are updated every 12 hours and attempt to predict only 36 hours into
the future. The four images show the predicated path of air
emitted at four different times, at 6 hour spacings.
Once the animation has stopped, running your cursor over the date-time
list on the right will step the images through these dates and
times. Add 9 hours to UTC to get Japanese time.
The Wikipedia page has a section on wind prediction:
On the afternoon of Sunday 2011-03-20 this section had an
animated gif of a NOAA HYSPLIT model predicting winds to 25
March. Note that the arrows in that animation point to the
direction the wind is coming from. The wind direction is in the direction opposite these arrows
I haven't figured out how to use the HYSPLIT site to reliably generate
something such as this image. So I suggest using the above
predictive charts from Finland initially, and checking back on this
section of the Wikipedia article to see if someone has an updated .gif
they created with HYSPLIT.
A map showing recent wind
for the region north of Tokyo, where the reactors are situated.
The reactor site is just to the left and slightly below the "F" of
Below is an archived copy
, from 2011-03-15 20:00 JST, with the reactor
Similarly, for the Tokyo region, which is to the south. About 20%
of the bottom of the above map overlaps with the top 20% of this map:
The overall map for Japan is:
See also Jeff Masters' WunderBlog, where he analyses wind predictions:
Also, the Austrian Weather Service http://www.zamg.ac.at/
runs daily predictions of the path taken by winds from the power plant. Look for "Fukushima" under "Neue Informationen".
Radiation levels and real-time monitors
A site which is supposed to report
radiation levels in real-time:
has some limitations. (The following notes are from 2011-03-18.) Firstly, many prefectures have no
sensors. Secondly, in some prefectures which do, including
Fukushima and to the north, Miyagi, there are no results. They are depicted as "under
survey". It is unclear whether this is due to official suppression of figures, or
to the entire sensor network in each prefecture not working.
Two non-official sites concerning radiation levels are:
This page http://www.pref.tochigi.lg.jp/kinkyu/houshasen.html
links to a PDF (with an name which depends on the date and time) the
most recent radiation readings in Utsunomiya, the capital of Tochigi
prefecture, about 150km to the south-west of Fukushima Dia-Ichi.
I have not been able to read these PDFs. I found it convenient to
open the above page with Google's Chrome browser, which offered an
English translation. The second green heading and the text which
follows, is translated by Google into the following:
The last dose of the situation
Heisei 23 March twenty-two now at twelve
0.153 microsievert Tochigi Public Health and Environment / hour.
Nasu Town Hall microsievert 0.56 / hour.
Imaichi Health Center microsievert 0.55 / hour.
Haga building microsievert 0.12 / hour.
Oyama City Hall microsievert 0.18 / hour.
These Numbers, IT Does not Affect Health (Ref: Chest X-Ray Microsievert sixty.)
Even without translation, using Firefox, these figures are visible amongst the Japanese characters.
Radiation measurements are in the past - and safety
decisions need to be made according to our expectations of the
future. The wind could change and the emissions
from the reactors could change. So I think it is vital to avoid
being downwind of the reactors . . . but what distances should we worry
about? I have no idea, since no-one knows how much radiation the
be putting out. We don't even have a clear idea of how much
radiation the reactors have emitted so far, since most of it has been
out to sea. Since the reactors could emit more, due to
explosions, meltdowns or deliberate or accidental release of
radioactive steam or other gasses, no-one can reliably predict what
they will emit.
The figures at the above site are in nanogray per hour (nanojoules of
energy per kilogram of absorbing material, per hour. According to
the gray and the sievert are different types of unit, so there is no
direct conversion between nanograys or similar and microsieverts.
According to this article, which cites 
the average annual exposure to ionizing radiation is 3600
microsieverts. So this is nearly 9.8 microsieverts per day, or 0.4 microsieverts per hour
The isi.edu page gives the components of this - 16% is from artificial
sources and 55% is from breathing radon (a heavy short half-life
radioactive gas, which is produced by rocks which contain uranium and
therefore, with radioactive decay, radium).
The table at  http://www.ornl.gov/sci/env_rpt/aser95/tb-a-2.pdf
refers to different doses of radiation in units of "millirem". 1
millirem = 10 microsieverts. The table below is my own
compilation of this information, with other sources mentioned below,
all in the
units of microsieverts
and microsieverts per hour
. (I have converted the units and in some cases altered figures within a few percentage points to create rounded numbers.)
remember that radiation monitoring in Japan typically reported in terms of microsieverts per hour
it is necessary to consider how many hours this a person would be
subject to these levels for.
|Description and [source]
|Total dose in microsieverts
per hour, if this level was exper-
one day this would be equal to.
(Column 2 divided by 24)
|Likewise, in microsieverts per hour, but if the exposure
(Column 2 divided by 168)
|Approx daily background dose,
including from radon.   
|Cosmic rays from one-way flight
from New York to Los Angeles. 
|Cosmic ray exposure flying Tokyo to New York. 
|Chest X-ray. 
|Average annual occupational dose
of radiation workers in USA (1980). 
|Approx annual background dose,
including from radon.   
|CT-scan of abdomen. 
|Level at which EPA Protective
Action Guidelines state that public officials should take emergency action when this is a probable dose to a member
of the public from a nuclear accident. 
|420 to 2,100
|60 to 300
|Annual limit for occupational
exposure of radiation workers set by the U.S. Nuclear Regulatory Commission and DOE. 
(AKA 2.1 millisieverts)
|Estimated level at which an
acute dose would result in a lifetime excess risk of death from cancer 0.8%. 
|Increased lifetime risk of cancer raised by 1%  (See note 1.)
|Level at which doses received
over a short period of time produce
radiation sickness in varying degrees. At the lower end of this range,
people are expected to recover completely, given proper medical attention. At
the top of this range, most people will die within 60 days. 
|500,000 to 6,000,000
The other sources of information are  MIT: http://mitnse.com/2011/03/16/radiation-introduction-and-radiation-status-for-fukushima/
What Aircrews Should Know About Their Occupational Exposure to Ionizing Radiation
The FAA explain this figure of 250 millsieverts as raising the risk of
developing cancer by 1%. This is presumably means 1% more of all
the people exposed to this will contract cancer, rather than raising
the existing risk of contracting cancer by 1%. The figure applies
to long-term occupational exposure, for people 20 to 64 years
old. The impact of this quantity of radiation on younger people,
including children, babies and babies in-utero, would (I guess) be
higher than this. Also, (I guess) short term exposure to the same
quantity of radiation may be more damaging than if it is spread over
decades. Both these guesses are consistent with the 0.8% cancer
risk in the item above, for 100,000 microsieverts.
the Japanese Weather Bureau's current
page. From this there are archived pages and two weather prediction
It can be quite hard to see the outline of Japan in these charts.
The prediction charts are especially important, and contain arrows for
wind direction. In the northern hemisphere, low pressure systems
rotate anti-clockwise and highs clockwise. (So what are the
arrows in the prediction charts, pointing clockwise in the low pressure
system?) The general drift of
the systems is west to east at present.
The following page has infrared
which can be
animated. I suggest 12 or more hours of animation in 30 minute
steps, with color turned on, for the East Asia region. This
gives a an impression of the general direction of wind up to the
It seems that the bright white clouds are high altitude and the gray
ones are low altitude. I guess that the low-altitude ones are
more important, since the contaminated air from the reactors is
unlikely to rise to any great altitude, and because we are concerned
about the exposure of people on the ground.
The image below shows what the above page looks like. Click it to
see a bigger version, but more importantly, use the link above and the
large text wind map links above to find out about wind directions at
A more colourful but not necessarily more informative north pacific
An easier to view set of wind directions for the whole country is:
but it is not clear how these are generated. The more detailed
maps of the Japan Meteorological Agency linked to above are presumably
Television News in
This is the most immediate and up-to date source of information I know
ABC news in Australia has a good record of providing images and videos
soon after the events:
The BBC, CNN and various other sites are also good:
There are extensive, detailed and presumably well informed blog entries and discussions on the crisis at
for instance, this one which points to a paper on localised
criticalities (collections of fuel pellets probably at the bottom of
the reactor vessel where the fission chain reaction starts up
again). Also some thermal images of the reactor buildings on 21
(2011-04-02) has a special (free access) supplement on the earthquake, tsunami and nuclear crisis:
This includes a blog report
indicating that the fission chain reaction may have restarted in at least one reactor, with some comments debating this.
Some timely and presumably reliable
analysis of the problems with these reactors is at a blog site from MIT Nuclear and Science Engineering http://mitnse.com I think this is
I won't necessarily be up-to-date with
listing their topics, so please check the March archives http://mitnse.com/2011/03/
at this site.
I think (2011-03-19) the most important articles
See below for my explanation of decay heat, now with presumably
accurate figures from the above-mentioned article.
The Japan Atomic Industrial Forum
is publishing several updates a day
with a table listing key things about each reactor, its fuel rods and
its containment building:
The Nuclear Energy Institute
has some information via this page:
Background info on the crisis is here
(impossibly long URL).
's press release page (might work better with Internet
Explorer than Firefox)
World Nuclear News
has a bunch
of articles on the crisis:
The Nautilus Institute (a public policy think-tank) released a report
on the crisis on 2011-03-17:
This contains considerable detail about spent fuel rods, of which there
are thousands of tonnes at Fukushima Daiishi.
A highly informative document which
appears to be directly relevant to the stricken reactors. Some
images from this appear below.
Some other documents from the US Nuclear Regulatory Commission:
There's a 373 page report from the OECD in 2009 on the behaviour of
nuclear fuel in Loss of Coolant Accident situations:
Please suggest more sites.
This is in date order, so the latest
videos are at the end of this section.
The open-source VLC video player (http://www.videolan.org/vlc/
Windows, Mac, GNU/Linux etc.) should be able to play all these
videos. If, for some reason, you can't play the videos from your
web browser, you should be able to play them like this: Right click the
link, copy the link location (into your
computer's clipboard) and then in VLC use File > Open location from
clipboard. VLC will play from these files, starting immediately,
without having to download the entire video file.
The explosion of Unit 1 on 2011-03-12:
The explosion of Unit 3 on 2011-03-14:
Here is a 52 minute video from NHK TV's
English service. It was from early AM JST on 2011-03-17
and is a
roundup of the nuclear crisis, looking
at all the failures, the
dangers, and the evacuation of residents
This may have been a replay from the night of 2011-03-16. I think
the translation is done after the initial broadcast, rather than in
I missed the very first
part of it. It is 128kbps .rm (Real Media) format. It can
be played with Real Player (http://www.real.com) at least.
However, Real Player may try to download the entire file before it starts to play.
There are 3D graphic models of the reactors, based on the GE diagrams,
but they are not necessarily technically accurate. For instance,
they depict hydrogen leaving from the top of the core straight through
the reactor vessel wall and out of the secondary containment.
Still, it is an interesting record of how the Japanese media are
presenting this to an increasingly concerned public.
Here is the same program in 10 minute chunks, of about 9MB.
The starting times of the files are exact, so times mentioned below can
be used to index into chunks.
- 2:30 Shows the inside of a reactor-like vessel with water being
Graph of tsunami depth taken 45km north of the power plant. The
water dropped and then went to 7.3 metres higher than normal.
"The fuel oil tanks and other facilities along the coastline were all
Tsunami waves reached as much as 300 metres from the coastline.
The tsunami waves inundated parts of the facilities of the nuclear
plant. Electrical equipment was soaked in water and this is believed to
be the cause of the emergency core cooling device failure."
(2011-03-18 3:58 JST However, which of the structures near the
waterline before the tsunami, as can be seen from the current Google
Maps image, were the fuel tanks? I can't find a good reference
for this report/allegation that the generator fuel tanks were washed
away by the tsunami.)
2011-03-17 NHK helicopter close-up video of the damaged reactor
buildings. Presumably radioactive steam is coming out of some or
all of them.
This is from:
The discussion forum I
established. Please read and contribute!
There's a detailed set of blog entries, with comments, at:
or more generally, for the latest developments:
A roundup on 2011-03-15 is here
pointing to various blog posts at this site and to other information to
that date. The author, Prof. Barry Brook, seems to be rather
optimistic (crazily and unrealistically so, I think) in writing that
the situation is "stabilizing" on 2011-03-16, when there is not even
evaporative cooling. I think he overestimates the rate at which
decay heat is now declining, perhaps because he believes the decline to
be exponential (it's not, see below) and because it initially declines
Theres a small article on cooling the reactors at Scientific American
, with some
discussion comments from readers:
Some other discussion forums suggested by "gsgs", which I haven't
looked at in detail yet:
There must be other significant
discussion forums - please let me know of them.
Decay heat and some explanation of the
Below, is my explanation.
However, please refer to a more informed page:
Here is an annotated version of the graph from that page,
followed by the figures for the next year from that page, with
Larger version: Decay-heat-MIT-linear-918-x717.png
2 & 3
|March 11 2:46 PM
|March 11 2:47 PM
|March 11 2:48 PM
|March 11 2:50 PM
|March 11 :00 PM
|March 11 3:30 PM
|March 11 8:00 PM
till ~ 8 hours after quake
|March 12 8:00 AM
|March 12 8:00 PM
|2012 March 11
These graphs and figures are crucial to understanding the crisis.
After the main fission reaction of the reactors were shut down, in
about 4 seconds or so, by the fully raised control "rods", the power
output dropped to about 7% of what it had been in the hours, days and
This heat is due to the breakdown of the short-lived fission
byproducts, which remain within the ceramic fuel. Some of these
have a very short half-life, and so they split, emitting energy
electrons, alpha-particles (energetic helium nuclei) and/or gamma rays,
with lots of heat, generally within minutes. If you have a gram
of something with a
half-life of an hour, and hour later you will have half a gram of it,
and the other half would have turned into some other breakdown products
(atoms with smaller nuclei, electrons, helium nuclei etc.), some of the
isotopes with smaller nuclei (fewer protons and/or neutrons) may also
be radioactive, with their own half life, their own emission
of heat and radiation, and perhaps still further radioactive isotopes.
These reactors have electrical outputs of 460MW (megawatts) for
Unit 1 and 784MW for Units 2 and 3. The systems are
about 33% efficient, so the heat generation by the core, at full power,
is three times these figures. This is confirmed by the figures
contained in reactor reports at http://www.jaif.or.jp/english/
Unit 1 creates 1,380 MW of heat and units 2 and 3 create 3,381 MW.
The design of the reactors is that when they are shut down suddenly,
electrical power is needed to keep water circulating through the
reactor core, and to cool this with seawater, which needs to be pumped
through heat exchangers (condensers for steam, normally) underneath the
turbines. Since all the reactors were stopped suddenly,
power needed to come from one or more diesel generators - but they
failed after an hour, I understand due to damage from the
tsunami. As reported in the 52 minute NHK video archived above,
the white cylindrical fuel tanks for the diesel generators were located
at the waterfront, and were swept away by the tsunami.
Batteries kept this cooling regime going for another 8
hours. This is when the trouble really started.
Without the ability to pump water through the core and heat exchanger,
the operators could only cool the core by pumping water into it, and
allowing the resulting steam to escape. A little of this steam
have been able to be released into the secondary containment structure,
where it might condense and cool to liquid water, and so not generate
too much pressure. But this was apparently not an option and the
steam was released to the atmosphere.
Initially, this steam would have been reasonably pure water, with
short-lived radioactivity which people should not be near, but which
apparently breaks down within minutes or hours.
Without the steam release, pressure would have built up in the reactor
vessel to a level which could have caused it to burst, though it is
made of 10 to 15cm thick (4" to 6") steel.
However, the operators found it impossible to do this while
keeping every part of the fuel rods fully immersed in liquid
water. This resulted in some of the upper parts of the rods being
only immersed in steam. This caused the fuel rods to become much
the point where the zirconium metal of the tubes reacted with the
equally hot steam to rip the water molecules apart, generating hydrogen
gas with the oxygen going to form the white ceramic zirconium dioxide.
This destroys the metal structure of the tube. The helium gas
within the tube will then escape (it is there to improve heat transfer
between the cylindrical fuel pellets and the inside of the highly
conductive metal tubes).
Then water would have entered the tubes, often being heated to form
steam. The fuel contains uranium dioxide (and for Unit 3,
plutonium dioxide too) and a whole bunch of fission byproducts,
including radioactive isotopes with various half-lives. Some of
this would go into solution, or suspension as small particles, in the
Now, when the steam is vented from the reactor vessel, it carries
with it some of the radioactive material which is dispersed or
dissolved in the water and steam. This is the primary radioactive
danger which the reactors pose from 2011-03-13 and onwards.
The degree to which this radioactivity is released into the atmosphere
will depend primarily on the levels of radioactivity in the water/steam
in the reactor, and how much steam is vented to the atmosphere.
The rate of steam release depends primarily on the amount of heat which
is being generated, since this evaporative cooling is the main way of
cooling the core. (Some heat can also be taken out via conduction
through the steel reactor vessel, such as to a pool of water around the
bottom of it.)
So the above graph tells us roughly how much heat needs to be
dissipated and how quickly this will diminish in the days and weeks to
The explosions, so far, have been caused by the hydrogen mixing with
air and being ignited. The hydrogen adds to the pressure inside
the reactor vessel and would be released along with the steam.
Whether the hydrogen accumulated and exploded within the secondary
containment building (I guess for Unit 3) or just in the roofed top
section above the concrete containment (I guess Unit 1), it has somehow
exploded. The fact that these explosions happened shows how
little control the operators have had over the situation. How
hard can it be to ensure hydrogen vents to the atmosphere? It is
lighter than air and will float upwards.
The need to cool the core will diminish over time, provided the
rods do not melt together or collapse. However, it will
take until July before there is a halving of the energy output of
If the fuel concentrates itself, either as loose pellets and or as
molten ceramic fuel, it could, in principle, start up the fission
reaction again, since
it is no longer separated by space and by the control "rods".
This is unlikely, since the fuel used in these reactors is not highly
refined beyond 5% or so (the uranium-235 or plutonium-239 used in
nuclear weapons is highly refined - 90% or more). Furthermore,
the fission reaction in reactors depends largely on a medium which
"moderates" neutrons - slows them down. Only neutrons slowed down
to the ordinary velocities of atoms around room temperature to 800C or
so, so they are traveling at about 1km a second or so, react strongly
with fissile U235 and Pu239 to split them, so continuing the fission
reaction. This neutron moderator role is performed by water, in
these reactions, but a molten mass of fuel will have no water within it.
So a bomb-like chain reaction is unlikely in the molten fuel mass,
which is known as "corium" and resembles lava from a
volcano. But a restarting of the fission chain reaction is
not needed for this molten mass to get hotter and hotter. Just
the decay heat will cause it to heat up, unless all that heat is
removed by some means. It won't be if there is a big mass of this
stuff - tens of tonnes of molten fuel, and any other muck which has
been caught up in it. Molten corium can melt through the steel
reactor vessel and can melt concrete, which then becomes part of the
corium. Any remaining zirconium in the corium can oxidize - catch
fire - so providing a chemical source of heat in addition to the decay
To read more about this:
Then, it may get hotter and hotter, and could melt its way through the
steel reactor body, and then fall into
the secondary containment area below which is designed to split it up
and send it into the water-filled torus, where it should hopefully be
able to dissipate its heat better and cool down. Still, the decay
heat will be released, and some of this heat will be released by that
now radioactive water boiling as well.
Hot corium will also emit radioactive material into the air.
So the race is to keep the core cool, without it disintegrating any
more, while emitting as little vapor as possible, until the whole thing
can be cooled without emitting any steam at all. Then, the
reactor vessel can be sealed, and with continual cooling, it will
reduce its heat output in the months to come and it could be dismantled
and cleaned up.
This process will surely take months.
So the direction of the wind is really important.
Here are various images which I think
are worth archiving and making easily available. I have added
captions to them so they remain self-explanatory, in English at least,
no matter where they are copied.
(Added 2011-04-01) Detailed photos taken on 2011-03-20 by a drone aircraft:
(Added 2011-03-26) There are some photos of inside the damaged control rooms and other parts of the site at:
These were taken on 2011-03-23. (In case the above file
disappears, a copy is in the current directory, so append
nisa.meti.go.jp-en20110325-1-5.pdf to the www.firstpr.com.au/jncrisis/
This page at DigitalGlobe.com has the latest satellite images:
I made the following map to depict the
contaminated areas around the Chernobyl nuclear power plant at the same
scale as parts of Japan around the Fukushima I nuclear power plant.
Removing the yellow dome which forms part of the secondary
containment. This is in the "refueling floor" area which was
blown open and exposed with the explosion of Unit 1.
The refelling floor during a the refueling shut-down.
The refueling floor during reactor operation. The yellow dome
would be beneath this.
Inside the torus. If the core melts, collects in the bottom of
the reactor vessel, melts the steel of that vessel (15cm = 6" thick, I
think) the molten material is supposed to flow into pipes which
distribute it around the torus, where it is cooled by water and
dispersed. This is to reduce the chance of the 100 tonnes or so
of radioactive fuel from forming a critical mass and continuing the
fission reaction which heats it acutely and which could lead to a
Latest developments and a few comments
, here is a list of
developments. It is not at all comprehensive. Be sure to
see the Wikipedia article and timeline for more complete information:
JST is 9 hours ahead of UTC (London), two hours behind Australian
Eastern Daylight Savings time, 13 hours ahead of US east coast time and
16 hours ahead of US Pacific coast time.
2011-03-17 11:42 JST
Workers are back at the plant and there are plans for pumping water
into the reactor buildings. NHK TV showed helicopters dumping 7.5
tonnes of seawater, but it was largely ineffective (as acknowledged by
the commentators) because the helicopters were flying well above the
reactor buildings (I guess several hundred feet) and were moving fast
as the dropped the water.
There two major items of good news, in my view, is that Mother Nature's
Wind Department is still keeping the air moving offshore, and
that there have been no obvious explosions or meltdowns, despite a day
or so in which I understand no fresh water was pumped into the reactors
of units 1, 2 or 3, or into the pool of water which houses the fuel
rods from unit 4, which was shut down about 115 days ago (?? this
figure is from memory).
2011-03-20 3:20 JST
I understand the fuel rods in the storage pools have been covered with
water again. This should reduce emissions and the danger of these
rods melting and emitting more radiation.
Still, there are three reactors which have been running without water
(AFAIK) for two or more days. The fact that these reactors have
not, (AFAIK), melted down or emitted vastly greater amounts of
radiation is most encouraging. It was and still is reasonable to
expect their cores to melt, and perhaps to melt through the reactor
vessel if they are not constantly cooled by liquid water.
The amount of radiation which has been emitted to the atmosphere is
completely unknown, because it has generally been blown out to sea,
where there are no radiation monitors.
The saving grace of this whole crisis has been the wind generally
blowing out to sea. As far as I know, most people in Japan have
not experienced radiation exposure which would significantly damage
their health. This would not be true of the reactor workers, or
of some people living near to the plant.
Hopefully, in the days to come, the reactors will be cooled, initially
evaporatively (which means radioactive steam will be emitted). I
wonder when the decay heat will be low enough that they could be cooled
by having enough water in the reactors to cover the cores, and then
sealing the reactors against steam release, and so not using
evaporative cooling, but instead pouring water on the outside of the
reactor vessel to cool the entire reactor in this manner. This
would involve some evaporation, but that would be evaporating fresh
seawater, which would not involve release of radioactivity to the
atmosphere. Constant flows of water such as this would wash
radioactivity from the inside of the secondary containment buildings
out to sea, but I guess this would be less of a problem than using
evaporative cooling of the reactor water itself.
Most recent entry
This time last week, one really bad thing happened after another,
explosions and for a day or two complete withdrawal of people from the
site. Now we have gone for five days or so without any new explosions
and with more people and equipment on the scene. Generally, the
wind has been blowing the emissions out to sea.
While radiation levels have not been excessive for most Japanese people, radiation has been detected in food. The latest report
from the BBC indicates the operators still have no way of knowing what
is going on inside the reactor buildings. I assume most or all of
the instrumentation and pumps have been disabled by explosion or fire
So we still have three reactors with damaged cores, in badly damaged
buildings, with little or nothing in the way of sensors or ordinary
cooling arrangements, plus in unit 4, a large quantity of fuel rods
which have been exposed above water to high temperatures and fire and
which are now apparently being kept underwater . . . but there seems to
be a leak in the pool.
Hopefully the wind will continue blowing out to sea.
Dangers of various forms of power
Nuclear power is well known for its
complexity, cost and the dangers involved - when operating, if
attacked, and with profound long-term safety problems with the spent
fuel and decommissioning of the reactor. Nuclear power is unique
in that it can cause acute problems with radiation, cancer on a mass
scale and contamination of whole areas of land. This could be the
outcome of the Japanese crisis, if one of the cores melts down, or if
the current cooling difficulties continue and the wind blew from the
Coal fired power stations have their own problems, not least global
warming. I recall reading that coal-fired stations emit more
radiation than nuclear power stations, due to the radioactive elements
in the coal being dispersed into the atmosphere. (Does anyone
have a reference?)
I guess that in principle it would be possible to design a nuclear
plant which was much more failsafe than these 1960 BWR designs.
Still, the problem of the waste remains. I had a look at http://en.wikipedia.org/wiki/Thorium_fuel_cycle
. It looks complex and there is still the need for reactors,
handling and processing waste, with some long-lived radioactive
Unless someone can trick small nuclei to come together with ultrasound
or some other tricks, I think fusion energy
is a long way from being practical. Again, its a big-science,
high-tech, complex and dangerous business.
I hope that in Australia especially, we can develop large-scale solar
power plants, perhaps based on solar thermal designs which store the
heat for hours or a day or so, enabling generation into the
night. Until we do, we are going to be burning a lot of black and
brown coal and so seriously contributing to global warming.