Fukushima Daiichi, containment is a decoy!
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Andrei Sakharov (A. Caxapob) May 1989:
For my part, I am convinced that nuclear power is necessary for humankind.
We must develop it, but only by guaranteeing absolute safety, which means that the reactors are installed underground.
....
in preface of "The Truth About Chernobyl" by Grigori Medvedev (Albin Michel 1990)
To many, nuclear energy looks to be a relatively clean and logical choice in an era of increasing resource scarcity. Yet the record requires us to ask painful questions: have we correctly calculated its risks and costs? Are we doing all we can to keep the world’s people safe?
The unfortunate truth is that we are likely to see more such disasters
Ban Ki-Moon UN General secretary Kiev 20/04/2011
Containment:
Device to build trust, claiming to prevent radioactive nuclear material spreading.
The experiment currently underway at Fukushima Daiichi, since the March 11 event, conducted in parallel on various reactors, provides experience on different variants of degradation and demonstrates that this device plays perfectly its role in normal operation.
However in case of an incident, accident or unforeseen abnormal conditions, either unthinkable, or deliberately not selected, its effectiveness remains unproven.
The dispersal of radioactive material (iodine 131, cesium 137, strontium ...) is carried worldwide by air in a fortnight (March 23 in France) or even faster, in more significant concentrations if uncontrolled spread occurs, by international trade of agricultural products, including dairy products and leafy plants grown near the plant, for which the control thresholds will soon be raised
(EU 31 March) .
In case proximity of the ocean permits, a massive release of cooling water in open circuit will enter the marine food chain.
Containment vessels, to increase trust, are many:
(Sometimes also called containment barriers)
An outer enclosure,
(confinement building)
Lightweight sheet of metal on a metal structure, it is especially designed for its function, with a cubic form like a normal building not to arouse apprehension as could have the more industrial appearance of a reactor, the decoration painting gradient pattern is intended for the public to better integrate mentally in the natural environment.
This vessel is presented as a radioactive containment, which may retain glimpses of the core.
It protects the pool of spent fuel from the rain, as well as from the eyes, the crane and maintenance operations, and retains the potential emissions by the internal reduced pressure in normal operation.
It is tight enough to hold the hydrogen gas (which is quite difficult), the recent demonstrations have shown.
Incident hydrogen is generated by radiolysis or by reaction at high temperature of cooling water on the metal zirconium fuel rods in uncooled pool or core, after passing through the innermost containment and thicker one, accumulates and causes after several days (to evacuate the vicinity of the plant of the cameras too close) an explosion that blows the roof, discovering in the open air the inner wall of concrete, which can then be cooled as the pool, by external means adequate and improvised as tarp seawater of 7.5 tons per C47 helicopter, fire trucks, water, truck crane for delivery hose cement, once the ultimate possibilities means are exhausted.
The use of pump boat (found in ports, and that we see in action during the festivities) was not attempted, nor even perhaps have been considered, while the freshwater supply by barges is finally achieved in one day, from a nearby port after it was initially not established.
This explosion, not at all accidental, as it is perfectly reproducible in similar circumstances on successive neighboring reactors, provides a picture far less impressive and mastered, even reassuring as it can immediately be identified that it is not nuclear and is fully understood (hydrogen), although such an assumption, however, had not been previously stated or even considered, no action has apparently been taken during the construction of the outer wall to allow the evacuation of the hydrogen, or any attempted improvised emergency measure for this purpose (at least initially), except finally at reactors number 5 and 6 .
A closer analysis shows that highly radioactive material has been ejected from one of the explosions at least up to 1.5 km from the reactor, no one is sure that it comes from a pool or an explosion on a more internal vessel.
The repeatability of explosions despite the difference in their development, essentially horizontal or vertical allows unified communication without the need to enter this type of explanation.
Concrete enclosure:
(containment vessel/ Concrete shell / drywell)
Diagram of possible degradation of the reactors 1-3
Partial melting of the fuel rods in 1-3 cores is recognized April 15
It completely covers the metal enclosure of the core (pressure vessel) but does not in fact the cooling system, it provides mechanical protection of the inner enclosure, attenuation of possible radiation.
To prevent overpressure it seems possible and it is planned to evacuate the steam out of the chamber, resulting in the release of radioactivity.
The cooling of this chamber can be obtained by spraying outside once the outer wall was destroyed.
In fact the chamber is composed of two layers, an inner steel having a sealing function and provided with a removable top cap yellow, (the atmosphere inside is rendered inert with nitrogen in normal operation) the other outer concrete, not completely continuous, having a structural function and maintain a biological function of protection (radiation, neutrons), the latter being achieved at the top by moving parts displaced as required when loading/unloading.
This enclosure also seems to consist of a steel torus at the base automatically collecting excess water cooling in case of overpressure.
The cooling system of the core is not contained in the concrete enclosure, but goes outside to the turbine building.
Dry cavity in normal operation it is possible to inject water to try to cool the outside of the pressure vessel.
Fukushima Experience suggests (April 2) that the reactor 2 concrete enclosure (or at least one outer well) is cracked and has a crack through which the highly radioactive water escapes (7T/h) and seems to get it one way or another, the Pacific Ocean.
Apparently through ducts provided for power supply, considering probably a high water level, certainly in the turbine building.
In addition, a strike is arranged under the whole, without one is certain of his place in case of initial meltdown like the Chernobyl experience has shown.
Highly contaminated water is detected at 15 m depth.
Reactor pressure vessel:
20 cm thick steel reactor vessel that contains the core and communicates with the cooling system.
It contains water and steam (boiling water).
In fact as confinement it includes the entire primary cooling circuit, whose thickness may be different, the strength and tightness of this assembly is that of the weaker part.
In addition, the seal must be provided for insertion holes of the control rods located at the bottom of the vessel, which is probably more difficult in case of abnormal temperature or even early meltdown.
To prevent overpressure it is expected to evacuate volontarily the steam or H2 out of the chamber, resulting in the release of radioactivity.
If the pressure is reduced to atmospheric pressure it is a sign that containment is no longer assured.
The chamber con
finely
do nothing in the absence of electricity and cooling operation because it is quickly and inevitably destroyed by the evolution of the core in such conditions.
No cooling alternative relief is expected in the absence of electricity.
At Three Mile Island electric power had not failed.
Additional enclosure:
Palliative concept.
It is envisaged at the end of March (but not initially intended) to create a new containment, covering the reactors, as the sarcophagus at Chernobyl, but in textile form? noting the non-effectiveness of planned construction.
Its implementation does not seem (to April 5) planned before September.
Exclusion zones:
Initially 3 km, it covers a distance of 1.5 km at which were projected, traced and briefly covered pieces of nuclear fuel, presumably from pool during the explosions of hydrogen.
Extended to 10 km (including Dai-Ini) and 20 km radius it delineates a zone of radiation protection at the edge of which a daily dose greater than the annual permissible dose was found, and also provides some protection in case of unfavorable evolution (corium encounter with a body of water).
Foreign authorities (USA, SW) call for a distance of 70-80 km for their nationals.
The evacuation will always be presented as temporary, to be performed more quickly and avoid any emotional charge.
It is strongly recommended to bring his key documents, and not to allow children to abandon their security blanket.
Complementary concept palliative improvised introduced after a month (announced April 11) with a reassuring name on the control of events.
These areas outside the areas previously evacuated in emergencies, are not defined geometrically by a remote site, a priori criterion in the absence of precise knowledge of real radiological risk, but designated according to measurements in situ, in -view a breakdown of the contamination variable (leopard spot), depending on the location based on local geographical and meteorological conditions, and acceptance of a return to normal unlikely within 6 months to a year, to afford not to accumulate exposure to the same dose limits for nuclear staff (20 milliSievert example).
The evacuation of the public in these conditions could clearly be described as temporary, short term and would be to be done under a month to avoid massive movement simultaneously.
These areas may also involve areas in view of voluntary evacuations, shops and services are no longer available and where it is difficult to leave the population.
Containment:
Containment of the public is a technique designed to reassure the public against the effects of nuclear radiation, this technique is applied in an area surrounding the evacuation zone (20 to 30 km in Fukushima).
This stopgap measure suggest implicitly when it is announced a rapid return to normal.
The beneficiaries of these provisions are not supported for an evacuation, should live on their personal reserves and no longer have opened shops, quickly tap water is predicted to be unfit for consumption.
A distribution of iodine tablets can be made.
As the population is more numerous and dense, containment is preferred to evacuation to reduce the stress of relocation and logistical problems associated with the evacuation.
As and when a stable situation is established over time, but in a still radioactive atmosphere, an evacuation on a voluntary basis is suggested, after the absorption of increasing cumulative doses.
A lack of control or decontamination will required a certificate of non-contamination of evacuees or confined to reassure outsiders or already evacuated.
After one month (April 15) a lump sum provisionnary compensation will be offered by the operator on the government injunction, to displaced and confined persons, when it is accepted that this situation is irreversible, in the amount of $ 12,000 for families , $ 9,000 for singles, for a total of $ 600 million.
Pamperisation:
New technique (etymology: Pampers (tm)) using the absorption properties of certain materials to prevent leakage of diapers and nuclear power.
Fully developed for diapers and bedding for animals, the value of its use for nuclear power plants is not established to date (April 3).
This seemingly unsuccessfull method, has occupied the media space for 2 days before the desired objective is achieved by other means.
Recommended to replace the use of cement whose caracteristics are degraded in highly radioactive conditions, it has been positively challenged by the use of silicate soda ("liquid glass") to seal a porous soil.
The nuclear fuel of the core is removed after use and stored in a pool, until the decline of its radioactivity.
The fuel (radioactive nuclear waste ) must remain submerged.
The replenishment of water lost by evaporation must be assured of the order of 1 liter per second per 3000 m3.
The pools are not placed in a containment structure other than one in a slight depression, protecting from rain, lack of water not being considered.
In this case, radioactive materials can reach the environment (see Unit 4).
The pools are intended to receive components of the core after use through sub-water transfer, as well as new elements newly delivered prior to installation.
A pool may contain more fuel than the core, it is less likely to return to criticality, since the elements are placed further apart from each other.
Signs of renewed criticality in the pool No. 4 to 15 April Dominique Leglu
Nuclear reactor shutdown:
Situation in which nuclear chain reaction (neutrons) is stopped by insertion into the core of absorbent material (control bar).
The core consists of fuel and nuclear waste (fission products) remains a significant residual thermal (few MW) source . It is necessary to cool at all times to prevent its rise in temperature or melting.
Given the geometry of the core this cooling is not achieved statically but requires a flow of water.
It does not appear that the current design of power allows a simple thermosiphon passive movement (as in a storage pool, which simply requires the replenishment of water evaporated).
Cold Stop:
The situation safe shutdown, obtained after initial cooling, demands however the integrity of the cooling system (piping, pumps) and the permanent presence of electrical energy.
Use of this designation suggests the absence of this constraint.
Some reactors in the United States of America were changed after 2001, in order to ensure that emergency cooling by gravity.
Reactor unloaded:
A reactor is discharged during annual maintenance period where there shall be a rotation of the load by third parties.
A reactor discharged contains 2/3 of the fuel load. cf.
Meltdown:
This situation is to be avoided.
It is considered by some as highly unlikely (a priori)
Situation in which lack of adequate cooling, fuel and zirconium based ducts.
The geometry is changed, the control rods absorbing neutrons are no more operational (blocked) and the nuclear fuel can recover locally favorable conditions for the resumption of chain reaction.
Mixing between the fuel ducts, the steel enclosure forms a dense magma called
corium .
The mass of fuel the plant is about 15 000 kg (/ 150 90T/coeur T, 1500 T on the site?).
The critical mass of fissile material is for example about 15 kilograms, in the absence of any concentration of neutron.
In case of core meltdown, the recovery of the chain reaction, can provide a temperature rise, likely to reach the melting point of steel.
see China Syndrome
"Piercing the strike would take several days, leaving enough time to take all measures for protection" (sic).
situation to April 3
Resumption of criticality:
This condition can occur in a core where it can lead to total or partial fusion or in a pool when the conditions are met.
Various local phenomena may limit the rapid evolution in runaway case, without developing optimized energy as a nuclear weapon, can cause adverse effects such as Chernobyl.
The presence nondecreasing iodine 131 is an index that might suggest a cover of criticality.
Just as the presence of chlorine 38 during the use of saltwater for cooling, indicates the presence of neutrons, never absent, even at rest.
Two situations are possible, an extension of the cloud is limited by a weather phenomenon saving, eg the Azores, preferably at national borders (eg Chernobyl 1986), now those of the EU-27 (or the Schengen Area?), which seems to be the case now, the cloud will cover the entire planet, preferentially affected hemisphere (north in this case), thus ensuring a dilution such that the level will be declared unmeasurable at first, then non-significant, then certainly safe, at least without the need of taking any precautionary measure.
nothing directly about the tags ( CRI-RAD or SNRI ), tiny traces in rainwater but now no risk to health (we are not there).
On April 2nd China has detected the iodine 131 throughout its territory with the exception of Tibet (CCTV) at a concentration reassuring 100,000 times lower than the norm.
The absence of radiation hazard in itself mean that it radionuclides once inside the body directly or after concentration through the food chain may pose a risk to long term, at least statistically, in particular for those with longer half-life such as cesium?
even at concentrations initially undetectable in the atmosphere.
What is the distance at which the distribution of radioactive contaminants aerological becomes really harmless?
There is no information to that effect, the zone of 30 km, where it is initially advised to remain confined within, being probably a lower bound of that value.
Locally, it is obvious that the "cloud" is potentielllement dangerous, to avoid panic and should therefore not to broadcast the weather simulations, some are likely to realize, this policy seems to be implemented in a manner acknowledged in Japan .
Iodine pill:
Consisting of potassium iodide, dose for adults is 130 mg single dose, or 900 times the recommended daily intake of 150 µg.
The concept of use is taking pre-contaminant exposure.
This provides reassurance, giving a sense of control over the situation, especially in a phase of evacuation after confinement.
To control populations, this method is reserved in France to authorities , distributed symbolic way around plants in a radius of 10 km in order to overcome the distributing difficulties in emergency.
Distibution and nominally and free, this shows the care and foresight of the authorities, firstly, lets blame and document those who do not withdraw their tablets, or do not keep them constantly on hand, while suggesting a sense of security among the masses, not concerned by the distribution, which can thus be free to think of risk, which is well managed and clearly taken into account.
In the practice of crisis management, tablets were distributed by the French Embassy in Tokyo at the risk of offending the Japanese authorities and sent to Saint Pierre and Miquelon (prepositioning).
Saturation of thyroid by stable iodine is effective (factor 90), but has no effect with respect to the cesium whose long-term effects are more lasting (30 years instead of 8 days half-life).
A bit like the vaccine against hepatitis B does not protect against hepatitis C.
To minimize always possible inconvenience (more likely to occur among frail elderly) and the corresponding legal risks, and also allow an optimal allocation (rationing) in case of insufficient quantity available, the instruction manual limit advocating use to 45 years people, persons who have reached that age thus having little chance of developing cancer before they reach the age of the end of their useful lives or who were exposed at a young age to the consequences of atmospheric tests, to which their medical condition could possibly also be attributed.
In addition, the dose for iodine saturation, steady, fast action in less than an hour, is eliminated quickly and must be renewed every 24 hours if the contamination conditions were not suppressed.
the World Health Organization recommends the distribution of iodine tablets in a 500 km radius around each nuclear plant
If awareness of some of the people who experienced other crises and do not count only on the government for the necessary stocks in time, a media campaign was organized in the early days.
"L' express" March 16
The opinion of WHO
It is clear, that palliative seems hardly applicable in cases of diffuse contamination.
It will not be offered.
Everything will be done so that people can not access them, no distribution beyond the designated areas, non-availability in pharmacies by non-implementation from wholesalers, not importing generic drugs from foreign suppliers, including major pharmacy chains that could economically be tempted by the approach, dissemination of information successive reassuring message to pharmacists who have no stock, or discouraging the use of the product .
This in a context of news that could help increase awareness for a local accident.
Only 52% of French people concerned have withdrawn their plate following the campaign of the authorities to this effect.
In Belgium 40 million tablets
were supplied and are subject to a campaign since March 14, the distribution is expected around the Belgian nuclear power plants and each must be able to gain access: "The other Belgians will get a simple application ".
The strategy set out in the PPI in France is at the hands of the Prefets and covers (it seems) only the local accident.
It does not appear that any pre-established disposition exists for the case of Fukushima (which incidentally was impossible).
Is it possible to have a strategy of caution in case of low level diffuse contamination?
Is it better not be deficient in iodine?
What protection may be provided by a food supplement iodine supplementation, a daily intake by an intermediate dose (1 to 900) the daily intake?
with what risks?
Cooling system:
The cooling system is an essential component of the plant in normal operation.
It will extract all the thermal power of the core, only a portion of which is converted into electricity, much as in any heat engine for heating the landscape.
It is lined with various emergency systems and security which all require the presence of electrical energy.
No reservation freshwater pond near is planned, to avoid experiencing leakage (impossible) with the lamp to cool seawater, which will deteriorate the system, and no tank or even a simple basin outdoors of sufficient capacity is available to collect the highly contaminated water, generated by cooling open circuit desperately (
except the nearby ocean ).
Pacific Ocean:
It is the largest ocean in the world, the mass of water which is used to dilute to undetectable values and inconsequential very high amounts of pollutants especially nuclear, which dissolved, seem to spread more easily than oil pollutants .
The overflow of water very highly radioactive reactor coolant after sinking by very large volumes of water in open circuit can easily remove the radioactivity in the ocean and thereby lowering treatment costs (Local April 3).
Besides the benefits of an easy positioning for cooling in normal operation of nuclear plants by the sea is very immediate sense when leaving of the nominal operating mode, in particular the choice of the Pacific Ocean.
More (from April 4) the deliberate dumping in the ocean of almost all of the cooling water used since the beginning of the incident (about 10,000 m3 / 60,000 m3 in total) can remove this slightly radioactive water that night in pursuit of peaceful work, and frees storage capacity for water heavily contaminated, expected later in the process.
Threshold effect:
It does not seem to be any threshold effect statistically proven effect on radiation of nuclear origin.
One mechanism suggested is to treat the lack of effect on biological systems to the extent that they have self-repair process masking the initial effects of radiation.
These processes would be totally effective in systematically below a certain threshold (in speed? Dose?) Above and less effective.
It is obvious that these phenomena are highly variable among individuals, possibly with a genetic component.
The threshold concept is intellectually satisfying, however, to reassure, and Providence in the economic approach, or medico-technical problem.
Total electrical failure probability in a group of nuclear power plants:
It is very low: This situation has however made for 15 days in Fukushima.
for all reactors 1 to 4 which probably enjoyed a reunion at the circuits.
Oddly Units 5 and 6 a little off but apparently the same distance from the coast, does not appear to have suffered (they were stopped and a generator continued to operate).
At Fukushima (1-4) a rescue group seems to have worked at least for an hour, likely until earthquake-tsunami, and may have contributed to the good rebound control rods during the automatic shutdown .
The result has been taken into account by batteries, providing power for several hours (8) which probably reinforced an initial impression of low severity and such a relief after the Tsunami and allowing appprovisionnement of diesel mobile relief, which connect "s been impossible (making problem ?)....
Plutonium:
Essential component of the alternative fuel MOX used without much apprehension when reloading the reactor
a dose of one microgram is lethal. more. 10 tons were distributed in the atmosphere during atmospheric testing in the 20th century.
Nuclear plant safety:
We can be reassured:
"The safety systems and containment barriers reactors operating today are designed so that the radioactivity is confined even in case of a merger of the heart, the worst accident resulting in the loss of the reactor."
A nuclear reactor is safe, it is structurally designed to resist and stop in case of earthquake or tsunami (apparently checked to stop)
A reactor is stopped, of course, because he continues to be cooled by the main circuit or emergency (not verified the absence of current)
Only a reactor shut down and in maintenance (unloaded heart) is safe:
yes if the pool is full, which is apparently not done it for a pool of 3000 m3 located 4Floors height of a building affected by an earthquake and no water supply by gravity (see . Reactor No. 4).
This suggests that only a reactor shutdown, unloaded heart, and without fuel pool is safe, it does not produce electricity, but it consumes less than a reactor shutdown.
Precautions during the construction of nuclear power plants:
The facilities are all designed and constructed to withstand earthquakes, tsunamis, floods, airplane crashes, missiles.
Fukushima DAI-ICHI was designed to withstand a tsunami of 5.7 meters (6 / 7m).
"The tsunami was not expected at a height"
The Tsunami of 11 March is estimated at 14 m (/ 15m).
In Japan, Tsunami more than 30 m were recorded (19th century) and recently in Asia ACEH 24 m.
The tsunami of March 11 reached (at the bottom of a valley) 38.9 m 38.2 m higher than achieved in 1896.
Japan has no safety requirement at the national level, some plants have been changes recently (2007) following a review of risk assessment including the construction of a wall of protection that has saved the operation of a part of DAI-INI pumps.
Onagawa is constructed 14 meters above sea level.
Similarly, the earthquake predicted was less powerful (seven times) than that of 11 March (9.0)
However in view of the distance the shock has met the local specification limit of the plant
A quake in Onagawa has not met the specification limit of the central
The probability of an airliner (> 5.7 T) unwittingly crashed on a power plant is considered extremely low.
A speaker can not resist the fall of a Boeing 747.
During the construction of French power stations, the A380 did not exist.
Plants in Germany are specified (such as EPR) to withstand the crash of a fighter aircraft
It turns out that operating plants in France would survive the crash of a fighter plane mass although at a greatly subsonic speed
PRT stations are equipped with additional safety features, but does not seem to be wihout comments from safety authorities including the ASN
The Blayais nuclear power plant
along the Gironde was flooded in December 1999 when the storm with a mean tide and then requested a building of a dam designed to overcome stalling height of the site deemed insufficient after construction, was not performed by the operator.
Location of a nuclear power plant:
For reasons of proximity to cooling water, river or sea is sought.
The construction on the seafront is optimal, in the disaster, the land area to evacuate and who will pay is lower halves for a given radius considered, ideally even a promontory (ie. Cotentin) which is easier to deny access, or if sea a strip of land in the territory of the state concerned (Chooz) or on an Island (TMI).
Experiences of Hiroshima and Nagasaki:
Conducted at the end of World War II, they collected data on a representative human sample, which are still used to calibrate the levels of exposure in the use of nuclear power.
The masses of fissile material involved does not exceed each time the 10 kg, and given the success of the experiment, like the atmospheric tests later, we can assume that much of the plutonium being used has been transformed into a fission product and was not disseminated as it is in the atmosphere.
Japanese Roulette:
An expert report in 2007 estimated the likelihood of a tsunami with amplitude greater than 6m to 10% over the next 50 years.
The accident was due to a design error and evaluation of the environment and the lack of acceptance of the questioning of data deemed acquired.
A few years ago in Japan manipulation caused a criticality accident (2 dead)
(Tokai-mura in 1999) .
Russian roulette:
see Chernobyl.
Given the location, the tsunami risk was zero, the "event appeared after a voluntary operation exceptional for testing. It is a human resources problem.
Very nice simulation of the cloud have been presented, which shows the progress in digital technology since Chernobyl, and since the design of these plants is even earlier, do we have the means and will now be simulated with the current means the evolution of the reactor, its resistance under different scenarios of meltdown or criticality accident?
Or are they stored these results for insiders?
The plant type rugged is not the same as those built in France:
Chernobyl had no containment building (but an upper 1200 T slab blown ).
Fukushima Daiichi has (3!).
Chernobyl plant use graphite.
Chernobyl does not use MOX fuel (plutonium-based).
Fukushima Daiichi is cooled with boiling water (single circuit) original General Electric.
Plants in France have a double cooling technology (Westinghouse), which is a significant benefit for a minor incident.
Catastrophic situations are so serious that they must remain unthinkable and especially unthought ,
being impossible their probability is zero, then there is no need to worry about it.
In other words is it not the same thing ?:
The safety approach in force:
The safety approach in effect requires the operator to ensure, on the basis of assumptions very disadvantageous, the resistance of the installation of the reference accident, and to demonstrate that adequate provisions are made in terms of design and operation for the consequences of these accidents are acceptable.
The "probabilistic safety assessment" complement this approach are considered and combined hardware failures and human errors in assessing the probability of unacceptable consequences.
Both approaches, however, neither study accident scenarios whose probability of occurrence is extremely low.
Containment systems are designed and tested to withstand accident conditions of design.
but not beyond !
The loss of power to the site for a long time has never been taken into account in the safety of nuclear plants
In the case of Fukushima no exercise has probably been done to demonstrate the feasibility of using mobile groups in case of failure more than 8 H
Audit of European and French nuclear plants:
Operators and manufacturers are asked to assess in six months the consequences of situations not considered in the design and construction of power plants.
(I.e. those dismissed as improbable, as the most serious or most expensive)
No power, earthquake larger than specified
Weakly contaminated water:
Water of radio activity does not exceed 100 times the legal safety limit.
Severity of event:
PSA graded on a scale currently 1 to 7 (Chernobyl), the event was initially classified 4 by the Japanese, by claiming that a similarity with TMI, and confidence in containment.
The French ASN has classified quickly to level 6.
Given the multiplicity of reactors and pools on the site, multiple explosions, the real noticeable, and prospects of solving a par with Chernobyl seemed reasonably quickly.
The Japanese come to recognize after a month on April 12 that assessment on the level to 7.
While stating that only 10% of air emissions from Chernobyl have been made to date (which will be repeated in the media) suggests that TEPCO ultimate consequences could be even more important.
The discharge air carried an estimated 10% of that of Chernobyl, mostly in the early days.
Duration of follow-up work:
The situation there remains unpredictable.
(End of March ..)
(As announced on 14/04)
Several months (2 / 3 if all goes well) to thermally stabilize the reactors.
(3 / 9 months TEPCO to 18 / 4)
20 years to have a balance (experimental) on human health.
5 years to remove the fuel with special cranes (Toshiba).
14 years were needed to TMI.
limit dose level recommended in cases of emergency (Japan 2011):
250 milliSieverts
MilliSievert 100 / H
Nuclear Workers (France 2011):
20 milliSievert cumulative per year (previously 35) USA 50 milliSievert
General Public
1 mSv per year (excluding natural radioactivity)
limit of the area of 30km 1.4 mSv (per day?) site of Japanese TV
doses of 10 mSv accumulated since the beginning (20 days) in some places to 40 Km cancer risk (at least)
100 mSv (in less than 8 H)
immediate effect (nausea etc. ..)
1 Sv / h (0.7 to 1.5 sievert) (a few s or min)
lethal effect:
often postponed for a few months 3 Sievert (300 rem) is a good chance, 4.5 Sieverts (50%),> 5 Sieverts sometimes recoverable, 8 to 10 Sieverts certain death
a reference to U.S.
human body radioactivity 8000/10000 becquerels (decays per second)
Language Elements:
radioactivity measured (whatever) is not an immediate threat to human health.
the presence of radioactive iodine at very low levels.
These values are without health effects to people or the environment
The radioactivity of plutonium is determined by a simple sheet of paper.
(But you should not breathe it or swallow it!)
other elements of language:
Iodine
Iode 131 is not a greenhouse gas emissions.
Nuclear power is a fossil energy source.
Reserves are the same as for oil,the users and the pressure on the resource are not increased by selling plants everywhere.
Nuclear energy is no more a source of national independence to France, the uranium being imported.
This gathering of information is given without guarantee and only intended to solicit your thoughts.
Reporting to the site of any inaccuracies would be appreciated
The use of extracts of the text is authorized, subject to link.
Links to the site are allowed
miscellaneous links (with no guarantee of course)
Accidents
Chronologie_des_accidents
Centrale_nucléaire
Low doses
Hydrogen and fusion of the heart and other contingencies
catastrophe-de-fukushima.fr
www.sortirdunucleaire.org
200 000 cancers
tap water in San Francisco
rainwater in San Francisco
TEPCO is not insured
Dose of a state's nuclear reactor nuclear reactor Hukushima
TEPCO an example
A thread of discussion in English about design flaws
No iodine tablets to the French
Fukushima leaks
Glasnost in Fukushima
Situation at 11 April reply
Sylvestre Huet Libération
TEPCO un exemple
The known risk since 1972
Higher doses acceptable for Europeans
European settlement in the case of nuclear accident
Planks on radioactivity around Fukushim
Auf deutsch: The danger of pools
We will avoid the nuclear disaster
Contamination of France
WEBCAM plant Dai-ichi (1)
Photos of the Dai-ichi plant
Slideshow
Vasiily Nesterenko 5MT ?
What would be the major accident
Onagawa
Radio-activity in Japan in real time
Risk of nuclear power plant
Even if there were an accident of this type every year, I would consider nuclear energy as an interesting energy
Nature
Arnie Gundersen
Japan Quake
Network information CTBTO
IRSN documents:
BWR
facilities SAFETY
Environment
Radiation
* From the outset, there has been a strong awareness of the potential hazard of both nuclear criticality and release of radioactive materials.
* There have been three major reactor accidents in the history of civil nuclear power - Three Mile Island, Chernobyl and Fukushima. One was contained without harm to anyone, the next involved an intense fire without provision for containment, and the third severely tested the containment, allowing minor release of radioactivity.
* These are the only major accidents to have occurred in over 14,400 cumulative reactor-years of commercial operation in 32 countries.
* The risks from western nuclear power plants, in terms of the consequences of an accident or terrorist attack, are minimal compared with other commonly accepted risks. Nuclear power plants are very robust
* Safety is achieved through "defence in depth".
Lightweight sheet of metal on a metal structure, it is especially designed for its function, with a cubic form like a normal building not to arouse apprehension as could have the more industrial appearance of a reactor, the decoration painting gradient pattern is intended for the public to better integrate mentally in the natural environment.
