May 21, 2011
By Victor Kotsev
|Tokyo Electric Power Co. President Masataka Shimizu speaks during a news conference at the company's head office in Tokyo Friday, May 20, 2011. (AP / Itsuo Inouye)|
Several decades ago, an American with an active imagination and a twisted sense of geography coined the term "China syndrome" to denote the worst-case scenario for an accident in a nuclear power plant.
The phrase, popularized by a 1979 movie with the same name, refers to the possibility that nuclear fuel turned into red-hot lava could melt its way through the reactor bottom and the Earth's crust, "all the way down to China". Presumably, and much to the consternation of any geographer past the middle-school level, China would find itself on the opposite side of the Earth from the United States in this science-fiction setup.
Even though any area "on the opposite side of the Earth" from Japan is quite safe from the danger of molten uranium, plutonium and fission products from the Fukushima Daiichi plant erupting in a volcano, the nuclear installation seems to be going through a limited version of the China syndrome since it was damaged in an the aftermath of the massive earthquake and tsunami of March 11.
Some molten fuel may well have escaped the reactor vessels through holes created by the heat, the hydrogen explosions which happened days into the crisis, or both. More details are expected in the coming days and months as an intricate tale unfolds of unforeseen disaster, human error, suspicious cover-ups and gross exploitation of underpaid workers at the plant.
Last week, the plant's operator TEPCO announced that attempts to recycle highly radioactive water pumped as a coolant into unit 1 had failed because the water levels were too low.  The water simply kept disappearing - and having in mind that tens of thousands of tones of such water accumulated in the reactor basements, it is not difficult to guess where.
More recently, TEPCO admitted that most of the nuclear fuel rods had melted into a pile at the bottom of reactor 1, and that reactors 2 and 3 faced similar problems.  Engineers and government officials started for the first time to talk openly about holes in the reactor vessels.
In the most scary realistic scenario, the molten fuel could restart the nuclear chain reaction - in physics jargon, become "critical" - and start pumping out heat and radioactive isotopes with renewed force. The chain reaction was halted with the help of control rods and various other "moderators" immediately after the 9.0 earthquake that triggered the crisis, and all that remained was heat generated by decay (mostly beta decay, as a Duke University nuclear physicist explained to Asia Times Online last month ). This was sufficient to facilitate the meltdown and the hydrogen explosions that happened subsequently.
Once the fuel melts fully, however, the control rods can no longer prevent the chain reaction efficiently, and there is a danger that the latter might resume. Evidence of such an occurrence is inconclusive and consists mostly of the alleged presence of isotopes with very short half-lives weeks after the shutdown of the reactors.  Informed speculation suggests that this didn't happen, or only happened briefly and in a limited way. As Geoff Brumfiel writes in Nature,
There's some reason to think that this "China syndrome", as it is informally known, didn't happen. Nuclear engineers I've spoken to say that reactors like unit 1 are finicky beasts. Their fuel needs to be carefully configured to work, and they won't restart if the stuff is just a gloop on the bottom of the vessel. In addition, workers injected boric acid into the reactor just before the restart. Boron is a neutron absorber and would spoil any nuclear reactions. Moreover, temperature sensors at the bottom of the reactor vessel are continuing to function, suggesting it wasn't completely destroyed. 
The slight confusion in terms - Brumfiel uses "China syndrome" more narrowly to denote the fuel's becoming critical again, while others use it more broadly for situations where the fuel melts through the steel container - reflects the informal nature of the phrase.
His argument is supported by data showing that the temperature inside the reactors is around 100 degrees Celsius, close to the desired "cold shutdown" levels when active cooling would no longer be necessary (still, it may be months before a cold shutdown is reliably attained). Both Brumfiel and other experts, however, admit that temporary flashes of renewed criticality may have occurred and may still be liable to occur.
There are numerous other interesting technicalities and speculations involved in the China syndrome scenario, and Richard Muller's overview, published on the website of the Lawrence Berkley National Laboratory, is quite instructive. The most significant and least controversial bottom line is that escaped fuel would complicate enormously clean-up efforts, expose workers to unpredictable flashes of intense radioactivity, and threaten to contaminate the air, water and soil around the plant further with massive amounts of dangerous isotopes.
It is hard to overstate the significance of the latter - the danger is so real that newer-generation nuclear plants are designed with expensive special radiation traps to capture molten nuclear fuel. In an unfavorable sequence of events (for example, a powerful aftershock followed by a new tsunami), an area of tens of thousands of square kilometers could turn into a nuclear wasteland.
The damage to the ocean ecosystem, which has already absorbed large radioactive emissions, would be enormous. This new danger comes on top of the risks associated with the presence of hundreds of tons of spent nuclear fuel and highly contaminated water at the plant. As a side note illustrating the precarious conditions of storage, TEPCO just announced that it had purchased a "mega float" where it intends to put some of the water. 
Despite the setbacks, the operator has continued to insist that it would stick to its time-table of six to nine months to stabilize the plant.  How exactly it intends to do that is uncertain, and both it and the Japanese government are coming under increasing criticism for a lack of transparency and a coherent strategy in handling the situation.
Late last month, one of the top nuclear advisers to the government, Professor Toshiso Kosako, resigned in protest of what he termed "impromptu policy decisions, like playing a whack-a-mole game, ignoring proper procedures".
A newly-released set of documents and logs from the early hours and days of the crisis took the government "off-guard"  by suggesting that a "worker error may have led to meltdown". A TEPCO spokesman told the Japan Times on Tuesday that a worker may have shut down a critical safety mechanism soon after the earthquake in an erroneous interpretation of the safety procedures.  According to these documents, the meltdown at unit 1 happened within 16 hours of the earthquake, and the hydrogen explosion at the unit the next day hampered additionally the efforts to restore the power supply to the entire plant.
The documents, some analysts point out, could serve to exonerate the American company General Electric, which manufactured the reactors, from its share of the blame. It looks, therefore, as if the blame-game is intensifying. If the reports of human error are confirmed, this would bring to the fore discussions about the state of preparedness of the plant operators for a crisis.
Both TEPCO and the government have promised compensation to those most gravely affected by the crisis, but to many this is too little, too late.
As Asia Times Online reported this month, the authorities are also taking heat for employing underpaid contract workers for the cleanup effort, without providing them with protective gear and adequate information about the risks.  According to a recent report in Japan Today, a man in his sixties was lured to work in the plant with a spurious job ad. 
The alleged cover-ups mean that as workers slowly and cautiously make their way into the reactors - this is how the complete meltdown at unit 1 was confirmed - more grave reports about the true situation at the plant can be expected.
1. Japan Reactor-Core Damage Is Worse Than Expected, Delaying Tepco's Cleanup, Bloomberg, May 12, 2011.
2. Meltdown may have occurred also at Nos. 2, 3 reactors, Japan Today, May 17, 2011.
3. Japan nuclear crisis goes global, Asia Times Online April 15, 2011.
4. Japan faces more than a decade of nuclear clean-up, Nature, April 2011.
5. Understanding the complete meltdown at Fukushima unit 1, Nature, May 13, 2011.
6. Tepco to Get Storage Float in May, Decontaminate Water From June , Business Week, May 20, 2011.
7. TEPCO's timetable for stabilizing crisis remains intact: Kan Japan Today, May 16, 2011.
8. Edano caught off guard by new pre-tsunami nuclear plant info, Japan Today May 17, 2011.
9. Worker error may have led to meltdown, Japan Times, May 17, 2011.
10. Front line at Fukushima, Asia Times Online, May 4, 2011; Dying for TEPCO, Asia Times Online, 3 May 2011.
11. Job seeker says ending up at nuclear plant not mentioned in ad, Japan Today, May 9, 2011.