Cooling system breakdowns at Fukushima Daiichi Unit 4 high-level radioactive waste storage pool risk catastrophic "boil down" fire

While international concern has focused on the risk of a big earthquake draining away the cooling water from the Fukushima Daiichi Unit 4 high-level radioactive waste storage pool and sparking a catastrophic fire, a more mundane pathway to disaster keeps rearing its ugly head: the simple malfunction of the pool's ad hoc cooling system. As the Mainichi has reported, most recently, such breakdowns have occurred on both June 4th and June 30th. As soon as the cooling system breaks down, the pool water begins to heat up due to the 1 Megawatt of heat still emitted by the irradiated nuclear fuel stored in the Unit 4 pool, even though some of it has already radioactively decayed for many years or even decades. If the water begins to boil, and evaporates away until the tops of the irradiated nuclear fuel assemblies are exposed to air, they could then catch fire, spewing large quantities of hazardous radioactive cesium-137, cesium-134, and other volatile radionuclides directly into the environment.

Regarding the latest breakdown, Aileen Mioko Smith of Green Action Japan provided immediate, real time translations into English on the news breaking in Japanese language media outlets:

"The latest news (Sankei 7:55am 1 July Japan time) is that Tepco [Tokyo Electric Power Co.] will re-route the UPS and restart the cooling for the Unit 4 spent nuclear fuel pool. At this writing, about 58 hours remain before the temperature reaches the safety limit of 65 degrees [Celsius]."

Sankei News, 1 July (Sunday) 7:55, Fukushima Daiichi, Japanese language article http://headlines.yahoo.co.jp/hl?a=20120701-00000089-san-soci

"Around 6:25am on (June) 30th, The alarm of the coolant system equipment of the Unit 4 spent nuclear fuel pool rang and the equipment stopped automatically. The pool temperature is not going up rapidly and Tepco
will begin restoration measures on (July) 1st. Tepco states there is not leak [a] of radioactive materials from the water."

"According to Tepco, it appears that they connected the main electric source and the coolant system equipment, and the UPS (literal translation: electric source equipment that will not have power failure) broke down (malfunctioned). They tried to undertake cooling with the reserve (stand-by) sytem, however because it was using the same UPS, they could not get it restarted. They will re-route the UPS and restart the cooling. 60 hours remain before the temperature will attain the safety limit of 65 degrees [Celsius]."

Aileen also translated the following Jiji news coverage from Japanese into English:

JIJI, 30 June (Saturday) 23:34, Unit 4 Coolant System Equipment Stops--Irregularities in 2 pumps /
Tepco Fukushima Daiichi, http://headlines.yahoo.co.jp/hl?a=20120630-00000150-jij-soci

"Tepco announced on the 30th that the alarm system which indicates irregularity of the Fukushima Daiichi Unit 4 spent nuclear fuel coolant equipment system sounded, and the equipment shutdown automatically.

According to Tepco and NISA [the federal government's Nuclear and Industrial Safety Agency], the alarm rang around 6:25am on the 30th. Both (two) of the two coolant system equipment pumps stopped working. It is stated that there is a possibility that the emergency power source equipment has broken down (malfunctioned).

Tepco intends to begin repair work from the 1st onward. Although the pool water temperature which was 31 degrees [Celsius] when the coolant system equipment stopped went up to 36.6 degrees at 6:00PM on the 30th, NISA states, 'There is about 60 hours leeway before the temperature will reach 65 degrees which is the safety limit.'"

Aileen reported that on July 1st, "Jiji reported at 16:23 that the Fukushima Unit 4 Pool coolant system had been repaired. Coolant temperature had risen to 42.9 [degrees Celsius] when repairs were completed."

Restart of Ohi Unit 3 complicated by turbine vibration

As conveyed by Lucas Hixson at Enformable Nuclear News, the first restart of an atomic reactor in Japan after the March 11, 2011 beginning of the Fukushima Daiichi nuclear catastrophe has been delayed by at least a day, due to excessive vibration in the plant's turbine -- even though the reactor is only running at 5% power levels.

Two walls bulging at "tilting" Fukushima Daiichi Unit 4 reactor building

The New York Times has reported that the Tokyo Electric Power Company has admitted that two of the walls at Fukushima Daiichi Unit 4 are bulging, while the entire reactor building itself is tilting. Fears are mounting that a large earthquake could collapse the building, or its high-level radioactive waste storage pool containing 1,331 irradiated nuclear fuel assemblies. Without cooling water, the high-level radioactive waste could quickly catch fire, emitting catastrophic amounts of deadly radioactivity directly into the environment. Despite downplaying and even denying the potential for catastrophe, Tepco has accelerated its plans to remove the irradiated nuclear fuel from the vulnerable pool by later this year.

Will imminent report on Japan nuclear disaster point to earthquake?

A Japanese parliamentary panel is due to release - as early as this week - the results of its in investigation into the Fukushima Daiichi nuclear disaster. The report could point to what many experts have already asserted was the cause: the magnitude 9.0 earthquake. Despite denials by the government and TEPCO, a number of seismologists and other experts have suggested the earthquake and not the tsunami caused the meltdowns. Fumiya Tanabe, a former senior researcher at the government's Japan Atomic Energy Agency, conducted his own analysis of data released by the government and Tepco, and concluded that reactor No. 2's cooling facility, called a suppression chamber, was likely seriously damaged by the earthquake, possibly releasing radioactive substances. If that were the case, all other reactors of similar design—11 of which are still in use in Japan— "would come under close scrutiny," Mr. Tanabe said. Concerns have already been raised about the two Oi reactors approved for restart that, seismologists say, could be situated on an active fault line. An estimated 150,000 people demonstrated outside Prime Minister Noda's residence on Friday. Oi unit 3 was restarted on Sunday.

Deadly radiation doses in basement of Fukushima Daiichi Unit 1

Tokyo Electric Power Company (Tepco) has detected record levels of radioactivity in the basement at Fukushima Daiichi Unit 1, Agence France Press reports. The article states:

"Radiation levels above radioactive water in the basement reached up to 10,300 millisievert an hour, a dose that will kill humans within a short time after making them sick within minutes.

The annual allowed dose for workers at the stricken site is reached in only 20 seconds."

10,300 MSv/hr, or 1,030 Rem/hr, means workers cannot approach such areas. Robots and remote control equipment must be used. The problem is, the technology doesn't yet exist. Robotic equipment sent into Unit 2 several months ago was quickly short-circuited by high radiation fields. Decommissioning is expected to take decades and cost tens of billions of dollars or more.

When robots failed in high radiation fields in Chernobyl in 1986, human "bio-robots" were sent in instead. Countless thousands of the 800,000 to 1.2 million "liquidators" -- mostly young male privates in the army -- thrown at Chernobyl have died early deaths in the quarter century since.