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This is another clearinghouse diary for discussion and commentary about the ongoing nuclear disaster(s) in Japan. Previous diaries can be found listed in the Mothership.
More Below the Fold...
Here is a series of resources highlighted on the mothership and other ROVs to assist you in finding a variety of information regarding the crisis.
In spite of what
"that reputable scientist, Ann Coulter" thinks, the situation at the Daiichi power plant remains very serious. Admission of the gravity of the nuclear plant situation led Tokyo Electric Power Company Managing Director Akio Komiri to break down in tears yesterday,
as Japanese officials finally admit[ed] that [the] radiation leak is serious enough to kill people. Mother Jones
Spent fuel is proving to be the biggest threat in this crisis. 1814 tons of spent fuel are stored at the plant, 647 tons of this in the spent fuel pools at the 6 reactors (h/t to politik and Into the Woods). For perspective, the Chernobyl accident involved ~200 tons of nuclear fuel.
The spent fuel pools are a main priority as the water levels in several of them have become dangerously low. Reactor 4's pool poses special problems as its fuel was just changed in Dec. 2010, thus is relatively new. Reactor 3 is problematic in another way, as it uses MOX fuel which contains both uranium and plutonium. TEPCO has been dropping water from helicopters and shooting water with water cannons at the reactors for the last three days in hopes of hitting the spent fuel pools and re-covering the spent fuel currently in the pools. Although such efforts have produced steam from the damaged reactors, thus indicating some water must have hit the marks, such measures are hardly a sustainable solution to the problem, and can do little more than buy time.
This evening, it was reported that
The Tokyo Fire Department shot water into a spent-fuel pool of the No. 3 reactor in an operation that lasted more than 13 hours until 3:40 a.m., while the Defense Ministry plans to shoot water into a similar pool of the No. 4 reactor shortly.
More than 2,000 tons of water is believed to have been put into the No. 3 reactor's pool so far, exceeding the pool's capacity of 1,400 tons.
We are all crossing our fingers that the water hit its mark, and will do so for spent fuel pool 4 as well. (h/t to woolie)
Radiation levels at the plant are high.
NHK (link) reported yesterday evening (US time) that radiation levels near reactors 1 and 2 are ~10-15 mSv/hr.
Allowable radiation exposure levels increased again Kyodo News reports that high radiation levels have been hampering workers' abilities to get much done while on site.
Six workers at the crisis-hit Fukushima Daiichi nuclear power plant have been exposed to radiation levels beyond the limit applied to an emergency operation, Tokyo Electric Power Co. said Saturday, without elaborating on the work that they were engaged in. They are continuing to work on different tasks because they have not shown any abnormal signs since being exposed to over 100 millisieverts of radiation, the utility said.
In response,
The limit has been raised to 250 millisieverts for the ongoing crisis, the worst in Japan's history, by the Health, Labor and Welfare Ministry.
(h/t to politik)
In addition to raising the exposure limit, unmanned operations are being performed where possible
(Kyodo News).
Radiation in water and some foods, specifically milk and spinach from Fukushima prefecture have been detected. Only traces at allowable levels have been found in tap water. The levels found on spinach and in milk from Fukushima exceeded the allowable limits, prompting Japan to ban the sale of food products from Fukushima. Guardian UK has more information.
The disaster has been upgraded on the International Nuclear and Radiological Event Scale (INES) from a level 4 to a level 5 event on its 1-7 scale. What does this mean? gchaucer2 provided us with the following from INES:
Events are classified on the scale at seven levels: Levels 1–3 are called "incidents" and Levels 4–7 "accidents". The scale is designed so that the severity of an event is about ten times greater for each increase in level on the scale. Events without safety significance are called “deviations”and are classified Below Scale / Level 0.
Chaucer gives, in her
comment, INES examples of accidents at each level:
7. Chernobyl, 1986 -- effect on people and environment;
6. Kyshtym, Russia, 1957 -- effect on people and environment -- significant release due to exploding radioactive waste tank;
5. Windscale Pile, UK, 1957 -- effect on people and environment --fire in reactor core;
5. Three Mile Island, 1979 -- Radiological Barriers and Control;
4. Toakaimura, Japan 1999 -- effect on people and environment -- fatal exposures to workers after failure at nuke plant.
For more on INES, see discussion in this
thread.
It was reported that electrical cables had been laid to try to get power to the cooling systems at the reactors, although it is unknown what state either the electrical or cooling systems are in the reactors.
TEPCO hopes to have enough power restored to the plant by the end of the day Sunday to begin running the cooling systems at all the damaged reactors. Should such efforts fail, there has recently been talk of burying the plant in cement as a last resort. More on the logistics of such a prospect can be found this Telegraph UK article. (h/t to mahakali overdrive)
Reactor status update:The IAEA issued the following briefing on Mar 19, 2011 at 4:30 UTC:
Unit 1
Coolant within Unit 1 is covering about half of the fuel rods in the reactor, leading to fuel damage. High pressure within the reactor's containment led operators to vent gas from the containment. Later, an explosion destroyed the outer shell of the reactor building above the containment on 12 March. There are no indications of problems with either the reactor pressure vessel or the primary containment vessel. Efforts to pump seawater into the reactor core are continuing.
On 18 March, Japan assigned an INES rating of 5 to this unit.
Unit 2
Coolant within Unit 2 is covering about half of the fuel rods in the reactor, leading to fuel damage. Following an explosion on 15 March, Japanese officials expressed concerns that the reactor's containment may not be fully intact. NISA officials reported on 18 March that white smoke continues to emerge from the building. Efforts to pump seawater into the reactor core are continuing.
On 18 March, Japan assigned an INES rating of 5 to this unit.
Unit 3
Coolant within Unit 3 is covering about half of the fuel rods in the reactor, leading to fuel damage. High pressure within the reactor's containment led operators to vent gas from the containment. Later, an explosion destroyed the outer shell of the reactor building above the containment on 14 March. Following the explosion, Japanese officials expressed concerns that the reactor's containment may not be fully intact. NISA officials reported on 18 March that white smoke continues to emerge from the building. Efforts to pump seawater into the reactor core are continuing.
Of additional concern at Unit 3 is the condition of the spent fuel pool in the building. There are indications that there is an inadequate cooling water level in the pool, and Japanese authorities have addressed the problem by dropping water from helicopters into the building and spraying water from trucks. On 18 March, Japanese Self Defence Forces used seven fire trucks to continue spraying efforts. There is no data on the temperature of the water in the pool.
On 18 March, Japan assigned an INES rating of 5 to this unit.
Unit 4
All fuel had been removed from the reactor core for routine maintenance before the earthquake and placed into the spent fuel pool. A portion of the building's outer shell was damaged by the explosion at Unit 3 on 14 March, and there have been two reported fires - possibly including one in the spent fuel pool on 15 March -- that extinguished spontaneously, although smoke remained visible on 18 March. Authorities remain concerned about the condition of the spent fuel pool.
On 18 March, Japan assigned an INES rating of 4 to this site.
Unit 5 and 6
Shut down before the earthquake, there are no immediate concerns about these reactors' cores or containment. Instrumentation from both spent fuel pools, however, has shown gradually increasing temperatures. Officials have configured two diesel generators at Unit 6 to power water circulation in the spent fuel pools and cores of Units 5 and 6. Workers have opened holes in the roofs of both buildings to prevent the possible accumulation of hydrogen, which is suspected of causing explosions at other units.
Restoration of Grid
Progress has been achieved in restoring external power to the nuclear power plant, although it remains uncertain when full power will be available.
Spent Fuel Pool Temperatures: In a positive development, it was
confirmed this evening that power has been restored to unit 6, and cooling is functioning effectively with the temperature of the spent fuel pool down to 52 C at 3 a.m. Sunday (down from a high of 67.5 at 11pm on Saturday). The latest temperature information we've had for pool 5 was 66.5 ° C at 6:00 on March 19 (IAEA), although
NHK reported yesterday evening (US) that the cooling systems at these two reactors are now operating again, and that the temperature in #5 has gone down. NHK a few minutes ago reported that as of ~8:20 this morning, the temperature in #6 had further decreased to 37 degrees. (h/t to procrastinator john)
As for the the other 4,
spideymike noted that a Defense Ministry presser yesterday, it was reported that
the temperature measurements (taken using IR equipment from a helicopter earlier today) indicated that the temperature of the pools in reactors 1, 2, 3, and 4 (yes, all of them) were all below 100 C.
Let's hope that confirmation of that and of other cooling efforts' success comes soon. Unfortunately, as reported in
The Mainichi News, although more information and
footage taken from an RQ-4 Global Hawk drone was passed on to the Japanese government with permission for public release from the U.S. Air Force
the Japanese government is reluctant to release the information. (h/t to peraspera)
Much more information on evacuation, radiation levels, etc can be found in the IAEA link above. These reports are updated regularly.
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