March 26
2011:
A reader,
from CEA, sends me a (daily) report from the Institute for Radiological Protection and Nuclear Safety (IRSN), in French.
He specifies: "This is the real information about the status of the Fukushima site."
This report appears less optimistic than the one provided by a French engineer living on-site, who comments on information supplied by official Japanese services.
IRSN Report of March 25, 2011
Excerpt:
IRSN
Institute for Radiological Protection and Nuclear Safety
Information Note
Status of nuclear power plants in Japan following the major earthquake on March 11, 2011
Situation as of March 25 at 08:00
Reactor Status
IRSN remains deeply concerned about the current status of reactors No. 1, 2, and 3
(risk of material failure due to massive amounts of salt in the reactor vessels and containment buildings, lack of a sustainable system capable of removing residual heat...). This fragility is expected to persist for weeks or even months, given the difficulty.
IRSN is examining possible scenarios for worsening conditions,
particularly scenarios involving a rupture of the containment vessel of reactor No. 3.
It will be difficult to confirm such a scenario, but its potential impact in terms of radioactive releases into the environment is being taken into account.
Reactor No. 1
The rate of seawater injection into the reactor vessel has been adjusted (10 m³/h) to control temperature above the core. This flow rate should allow for the removal of residual heat. Pressure within the containment building has stabilized. It will not be necessary to depressurize this vessel in the near future.
Reactor No. 2
Seawater injection into the reactor vessel is being maintained to ensure core cooling, which remains partially uncovered. The containment building may be damaged. The situation has not changed, and depressurization of the containment vessel is currently unnecessary. The control room should be resupplied today.
Reactor No. 3
Seawater injection into the reactor vessel is being maintained to ensure core cooling, although the core remains partially dehydrated.
The containment building appears no longer airtight according to pressure indicators; this loss of integrity is likely responsible for continuous, unfiltered radioactive releases into the environment.
The smoke emission detected on March 23 has ceased. IRSN is analyzing possible causes of containment failure in reactor No. 3.
One hypothesis under examination by IRSN involves the possibility of a vessel rupture followed by interaction between corium (a mixture of molten fuel and metal) and concrete at the bottom of the containment building.
The environmental impact of such an event is currently under assessment.
Three operators were contaminated on March 24 in the turbine building of reactor No. 3.
Material audit work has been suspended. These operations aimed to restore freshwater supply to the reactor.
Reactor No. 4
The core of this reactor contains no fuel.
Reactors No. 5 and 6
The reactors are properly cooled (core and fuel assemblies in the cooling pool).
Japanese engineers are concerned that salt from the seawater cooling system is clogging electromagnetic valves, which can only be controlled remotely. A malfunction of this type could have serious consequences, and their priority is to return to freshwater cooling.
So, what is the solution?
I have firsthand information—news I’ve gathered during two international conferences, in Vilnius in 2008 and Jeju, Korea, in October 2010, and in close proximity to Malcolm Haines himself. Nexus has agreed to publish this news article, which will appear in the next issue.
These details will simultaneously amplify hopes and fears surrounding this new technology of ultra-high temperatures. Without spoiling the intrigue (the article will be written quickly):
In 2005, Americans achieved 3.7 billion degrees in Sandia’s Z-machine. Prioritizing military applications (pure fusion bombs), they concealed all that could be hidden. With ZR, electrical intensity increased from 17 to 26 million amperes, and the machine’s performance is now classified.
March 20
2011:
Is it important to produce a series on this Japanese disaster? There are so many catastrophes on Earth that we’re overwhelmed. What can be said is that this disaster stems from another human folly: building low-cost nuclear power plants (as is the case with all Japanese nuclear plants) in a country repeatedly devastated by tsunamis. Otherwise, building cheaper nuclear plants and profiting from them.
Ignoring the recommendations of seismology specialists who urged strengthening earthquake protection.
Negligence.
The Japanese astonish us with their spectacular progress in robotics. In Japan, robots can ride bicycles, speak, and smile. They build humanoid robots with style—these will likely be sold like artificial pets or electronic companions to urban dwellers suffering from loneliness. This reminds me of a chapter in Ray Bradbury’s The Martian Chronicles, which I highly recommend reading or rereading.
Yet, in Japan, no one invested in safety robots capable of climbing through rubble—and especially not ones shielded with lead to withstand intense radiation. Japan had to import them from abroad.
We’ve seen one of these responsible officials, “overcome by emotion,” shed crocodile tears (but who wouldn’t sit beside machine operators dangerously approaching reactors in an attempt to cool them down?). In Japan, political or economic leaders who ruined hundreds of thousands of decent lives periodically appear before the media to offer public apologies. The head of a nuclear disaster sheds a few tears—this replaces the traditional Japanese ritual of seppuku, suicide by sword.
This video shows how waste from boiling water reactor operation is handled—manipulated remotely and stored in a water pool, where the water acts as a radiation-absorbing shield.
You must understand one thing: In the nuclear industry, waste from electricity production—highly radioactive and dangerous to handle—is simply stored
very close to the reactor,
in ordinary water pools. Water is sufficient to block various types of radiation. Later, this waste will be transported to reprocessing centers, such as La Hague, to extract future fuel for... fast breeder reactors. These wastes are
far from inert
and constitute material just as dangerous as the reactor core itself.
Used fuel storage pool
This pool is located immediately adjacent to the reactor for ease of handling.
A close-up on these “structures” containing the “pencils”:
60 “pencils” per “assembly” in Japanese reactors
Zooming in further, we can see details of these “pencils,”
which make up the “structures.” These are zirconium tubes (also called “gines”), filled with “fuel pellets”: uranium oxides, or, in the case of “MOX,” a mixture of uranium oxide and plutonium oxide. If the water surrounding these structures evaporates, the residual heat generated by these densely packed structures is sufficient to rapidly damage the zirconium tubes, allowing the pellets to escape and accumulate at the bottom of the pool. Unless an explosive event disperses these materials around the reactor.
Source for what follows:
http://allthingsnuclear.org/tagged/Japan_nuclear
The vessel (here, open) and the “pool” are connected by doors and locking mechanisms.
Periodically, “the reactor is shut down.” Control rods are raised, reducing reactor activity to its minimum—still not zero, as fission products continue to decay and release heat (60 megawatts, one-tenth of nominal operating power). The lock isolating the top of the reactor from the storage pool is opened. Water fills all available space. Handling of the fuel assemblies now occurs underwater, using a crane and telescopic arm—either to remove “used” assemblies or replace them with “new” ones. In any case, unless a reprocessing industry like La Hague takes over, the “used” assemblies will remain stored in a nearby pool, continuing to heat the water of the “storage pool for spent fuel and transit fuel for new elements.”
Handling and assembly under a water shield, providing radiation protection
Here is a photo showing such handling, taken at a U.S. nuclear power plant—Brown Ferry in Alabama.
Transfer of a used assembly to the storage pool
The name “cattle chute” was chosen due to the resemblance between these walkways and those leading livestock to slaughter.
This photo is taken by the crane operator. Under his feet: water protecting him from radiation.
A few meters below, the distinct blue glow corresponding to radiation emitted by “used” fuel elements is clearly visible. It’s evident they are far from passive!
Here is another photograph of a U.S. reactor storage pool (Alabama), empty and awaiting use.
Several decades ago, I visited an experimental reactor
Pégase
installed at
Cadarache.
Looking through the clear water, we could see “the entire interior of the reactor,” surrounded by a blue halo,
located ten meters below.
It was like facing death itself—the raw nuclear poison just inches away. The speed of emitted particles was not faster than light in a vacuum, but faster than light’s speed in water, which is over 200,000 km/s. The ratio 200,000 / 300,000 = 1.5 corresponds to water’s refractive index. The particles were thus emitted at “supersonic speed” relative to light in this medium, and we clearly saw phenomena resembling “shockwaves”—what we call
Cherenkov radiation.
In any medium other than vacuum, light propagation time is extended due to the absorption and emission delays of photons by atoms and molecules. But between atoms, photons travel at 300,000 km/s.
Pégase
(35 thermal megawatts), a research and testing reactor, commissioned in 1963 at Cadarache, it is an atomic pile used to test fuels for gas-cooled reactors.
The Pégase reactor pool was converted in 1980 to store 2,703 containers holding 64 kg of plutonium.
Sources for what follows:
http://www3.nhk.or.jp/news/genpatsu-fukushima
http://allthingsnuclear.org/tagged/Japan_nuclear
Each joint element (see above) weighs 170 kg and contains 60 “pencils.” The storage pool of reactor No. 3 contained as much highly toxic “used” fuel as... its core.
Below is a photo broadcast by NHK of Japan, indicating that watering (with seawater) must be done at a height of 22 meters.
Watering Japanese reactors requires spraying (seawater) at a height of 22 meters (source: Japanese TV NHK)
Watering crane mounted on a mobile vehicle
Test of this watering crane
March 22, 2011:
As reported by a reader, it appears to be a remote concrete pump, as indicated by the photo he sent me (and I thank him):
On the left, the concrete transport truck with its rotating mixer.
Of course, such a pole could be used to deliver water at a height of 22 meters—where cooling would be most effective. If used to flood the reactor under concrete, it would be far more serious. This would imply that the core cooling system—or one of them—could have been destroyed.
Wait...
We can only hope that in Japan, the situation is not as critical as it seems, when speaking of nuclear (setting aside the fact that tsunami-related fatalities have reached 20,000 so far).
The fact remains that these events brutally remind us of the risks associated with nuclear power.