Status of quake-stricken reactors at Fukushima nuclear power plants

Kyodo News (Japan) ^ | March 17, 2011

[Oldeconomybuyer]

The following is the known status as of Thursday night of each of the six reactors at the Fukushima No. 1 nuclear power plant and the four reactors at the Fukushima No. 2 plant, both in Fukushima Prefecture, which were crippled by Friday's magnitude 9.0 earthquake and the ensuing tsunami.

Fukushima No. 1 plant

-- Reactor No. 1 - Operation suspended after quake, cooling failure, partial melting of core, vapor vented, building housing reactor damaged Saturday by hydrogen explosion, seawater being pumped in.

-- Reactor No. 2 - Operation suspended after quake, cooling failure, seawater being pumped in, fuel rods fully exposed temporarily, vapor vented, building housing reactor damaged Monday by blast at reactor No. 3, damage to containment vessel feared, potential meltdown feared.

-- Reactor No. 3 - Operation suspended after quake, cooling failure, partial melting of core feared, vapor vented, seawater being pumped in, building housing reactor damaged Monday by hydrogen explosion, high-level radiation measured nearby on Tuesday, plume of smoke observed Wednesday and presumed to have come from spent-fuel storage pool, severe damage to containment vessel unlikely, seawater dumped over pool by helicopter on Thursday, water sprayed at it from ground.

-- Reactor No. 4 - Under maintenance when quake struck, fire Tuesday possibly caused by hydrogen explosion at pool holding spent fuel rods, abnormal temperature rise in spent-fuel storage pool, fire observed Wednesday at building housing reactor, pool water level feared receding, renewed nuclear chain reaction feared.

-- Reactors No. 5, 6 - Under maintenance when quake struck, water temperatures in spent-fuel storage pools increased to about 64 C on Thursday.

-- Spent-fuel storage pools at all reactors -- Cooling functions lost, water temperatures or levels unobservable at reactors No. 1 to 4.

Fukushima No. 2 plant

-- Reactors No. 1, 2, 4 - Operation suspended after quake, cooling failure, then cold shutdown.

-- Reactor No. 3 - Operation suspended after quake, cold shutdown.

==Kyodo

[The Sons of Liberty]

Thanks for posting this summary.

Listening to the news reporters, it is hard to follow and tell facts from fairy tale.

[Wolfstar]

Thanks very much for this summary. Reporting has been all over the place and clear as mud much of the time. Your summary makes the situation so much easier to understand.

Can you confirm or clarify one more point? The reason for all of these cascading failures was the initial failure of emergency power generating equipment at the facility? My best understanding is that power failed due to the earthquake and tsunami, and that the 2nd (diesel), 3rd (battery) and 4th (sea water) levels of fail-safe backups also failed. Without power, the coolant systems could not work.

The reason I'm asking this is because it's just beginning to seem rather odd that absolutely nothing the Japanese have tried from the very start has worked. No fail-safe system worked. No subsequent attempt to cool the first reactor with problems worked. Instead, the Japanese have struggled with a continuing cascade of failures. Yet they are hardly backwards people lacking expert knowledge of nuclear power plants. They are hardly unaware that a build-up of hydrogen could cause explosions (although not without a trigger such as a spark). They are one of the most technologically advanced countries on the planet. So I'm really curious as to why there has been such a drastic cascade of failures, one atop the other, with no end in sight.

[IamConservative]

-- Reactor No. 4 - Under maintenance when quake struck, fire Tuesday possibly caused by hydrogen explosion at pool holding spent fuel rods, abnormal temperature rise in spent-fuel storage pool, fire observed Wednesday at building housing reactor, pool water level feared receding, renewed nuclear chain reaction feared.

That seems to be the most ominous development.

[D-fendr]

Yes it is. And I'm not seeing that phrase on the NEI update or elsewhere. Here's the relevant NEI update:

Reactor 3 is in stable condition with seawater injection continuing. The primary containment is believed to be intact. Pressure in the containment has fluctuated due to venting of the reactor containment structure.

TEPCO officials say that although one side of the concrete wall of the fuel pool structure has collapsed, the steel liner of the pool remains intact, based on aerial photos of the reactor taken on March 17. The pool still has water providing some cooling for the fuel; however, helicopters dropped water on the reactor four times during the morning (Japan time) on March 17. Water also was sprayed at reactor 4 using high-pressure water cannons.

[Pentagon Leatherneck]

With a sub-critical mass present, that just means more/faster heat buildup.

TC

[IamConservative]

renewed nuclear chain reaction feared.

There has been so much reported but I believe I understand this reactor had recently undergone a fuel change. Spent fuel has the most decay heat right after changing, so it is not surprising it would be the hottest. If the nuclear chain reaction has started again, I wonder if the spent fuel is packaged is such a way that it will become a full melt or something less volatile?

[D-fendr]

Don’t know. I do know the rods are stored vertically and dispersed, not together.

The report is a concrete wall failed but the steel liner of the pond did not. Don’t know if the rod’s holding structure is intact, etc. I’d be interested to know, if they are still separated, what the scenario is if all water is lost.

Lots of unknowns here. Lemme know if you see any confirmation elsewhere of “renewed nuclear chain reaction feared” or reference to it.

thanks for your post.

[Toskrin]

I read from one official report that number 4 reactor’s rods had been removed for maintenance and were placed in the pool prior to the earthquake. This would mean that the reactor itself is empty but that the pool is more dangerous than the others.

[Somethng2ThnkAbout]

Yes. And I wonder as I read portions like those below just who this information is coming from: TEPCO? or the Japanese gov’t? or the former filtered by the latter?

“Reactor No. 2 - ... damage to containment vessel feared, potential meltdown feared.”

“Reactor No. 4 - ... pool water level feared receding, renewed nuclear chain reaction feared.”

Certainly supports (rather than contradicts) Washington’s and other nations’ extreme concerns and reasoning for extended evacuation zone & advisory for leaving greater Tokyo area, if not all of Japan. Makes Japan’s response in terms of evacuation of its people seem timid. And yes, I understand their gov’t is overwhelmed now. But how much more overwhelmed would/will it be when this doesn’t end favorably ... apparently the most likely scenario at this point?

[D-fendr]

From JAIF:

Status of Fukushima #1 power station as of 21:30, March 17, 2011
“Operation for filling the pool with water at unit-3”

NHK news reported on the operations conducted today for filling the pool with water at unit-3 as follows:

Water level is low at the spent fuel pools of unit-3. Considering possibility of damage to fuel rods in the pool outside the containment vessel, operation for filling the pool with water were conducted three times.

* 1st operation
Japan Self-Defense Forces dropped 4 huge buckets of seawater from helicopters in this morning. Lead plates were installed at the bottom of the helicopters to shield radiation and crew members wore radiation protection suits.

* 2nd operation
The National Police Agency tried to pour water from the ground with pumper truck in the evening. However, they were not able to come close because of high radiation and water did not reach the pool.

* 3rd operation
Japan Self-Defense Forces poured 30 tons of water from the ground with 5
special pumper trucks from 19:45 to 20:09. Because these trucks are special, they were able to do this operation without getting off the trucks. Effect of this operation is under evaluation.

[Somethng2ThnkAbout]

No wonder we’re finally getting more into this than before (for whatever reason(s) - it’ll be a week less than 12 hrs from now) .... and see last line below of Kyodo News release .... still does not bode well:

U.S. forces to send 9 experts to help Japan address nuke plant crisis
WASHINGTON, March 17, Kyodo

U.S. forces will send nine experts to Japan to help the country deal with the crisis at the Fukushima Daiichi nuclear plant, a Pentagon official said Thursday.

The nine are specialists in countermeasures against nuclear, biological and chemical weapons, the official said, adding that the U.S. military will continue to cooperate with Japan in addressing the emergency and see if the additional dispatch of troops or personnel is necessary.

Meanwhile, the U.S. Navy 7th Fleet said it has provided the Japanese government with 100 nuclear, biological and chemical firefighter suits.