Japan's Nukes Following Earthquake

[Marlin]

TEPCO has just released "diaries" from early in the accident giving us a better view of the sequence of events from the operators point of view.


The bulk of the materials, distributed on discs with digital files, show reams of raw numerical data. They include photos of broadsheet computer printouts and other formatted charts with thousands of data points for measurements of reactor heat, pressure, water levels, fuel rod positions and the status of cooling pumps, among other functions. Tokyo Electric, or Tepco, also released a smaller batch of more recent documents highlighting its various efforts to restore electric power to each of the reactors, a task that was achieved on April 26.

But a series of what Tepco terms reactor "diaries" from the first 48 hours after the quake include the most visually arresting materials. These feature snapshots of whiteboards on which plant employees—11 of whom remained in each of the plant's three control rooms—jotted down status updates on the progress of the reactor shutdowns and steadily increasing radiation levels around the facility.
Using red, black or blue ink markers, the plant operators appear to have scribbled down the notes quickly. Many are smudged or illegible. Others depict complex diagrams and are peppered with technical jargon or acronyms such as SBO for "station blackout."


http://online.wsj.com/article/SB10001424052748704281504576329011846064194.html

So helpless were the plant's engineers that, as dusk fell after Japan's devastating March 11 quake and tsunami, they were forced to scavenge flashlights from nearby homes. They pulled batteries from cars not washed away by the tsunami in a desperate effort to revive reactor gauges that weren't working properly. The plant's complete power loss contributed to a failure of relief vents on a dangerously overheating reactor, forcing workers to open valves by hand.

And in a significant miscalculation: At first, engineers weren't aware that the plant's emergency batteries were barely working, the investigation found—giving them a false impression that they had more time to make repairs. As a result, nuclear fuel began melting down hours earlier than previously assumed. This week Tokyo Electric Power Co., or Tepco, confirmed that one of the plant's six reactors suffered a substantial meltdown early in Day 1.

http://online.wsj.com/article/SB10001424052748704322804576302553455643510.html

[UncaBuffalo]

http://blogs.wsj.com/japanrealtime/2011/05/20/photos-when-the-tsunami-hit-fukushima-daiichi/?mod=WSJBlog&mod=WSJ_Japan_JapanRealTime

More tsunami pix...

[Matthew B]

Lots of interesting information in this paper from TEPCO:

http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_110525_01-e.pdf

Units 1-4 did not have RCIC.  They had isolation condensers.  Not only that, the isolation condensers were water cooled with 8 hours of water in the condenser reservoir. 

HPCI required DC power to operate.  The turbine lube oil pump was DC; it didn't have a shaft oil pump.  I think this may be common here too, anyone willing to verify that?

That's why they had trouble so quick:  8 hours later and without AC power they had no way to get water to the pressure vessel.  About the same time the instruments died from a lack of battery power is about the time they lost the isolation condenser from a lack of water.

They also verify that they didn't have the hardened vent modification.

[Marlin]

   The link to this article was Japan: seniors volunteer for 'suicide corps' I can't blame the press for that but pyramiding with a negative bias by the news link was clear. The reasons for the seniors work to perform the work and their risk analysis seems sound, and if you believe in radiation hormesis then the gentleman with cancer could even benefit.


Fukushima may have a group that could tackle the nuclear crisis looming over Japan. The Skilled Veterans Corps, retired engineers and professionals, want to volunteer to work in the dangerous conditions instead of putting younger generations at risk.
More than 200 Japanese retirees are seeking to replace younger workers at Fukushima while the plant is being stabilized.

http://www.digitaljournal.com/article/307378

[Marlin]

The Nuclear and Industrial Safety Agency (NISA) on June 6 revised the level of radioactivity of materials emitted from the crisis hit Fukushima No. 1 Nuclear Power Plant from 370,000 terabecquerels to 850,000 terabecquerels.

 (from 10,000,000 curies to 22,972,972.97 curies)

http://mdn.mainichi.jp/mdnnews/news/20110606p2a00m0na009000c.html

[TWillis]

The Japanese report to the IAEA

http://www.kantei.go.jp/foreign/kan/topics/201106/iaea_houkokusho_e.html

[Marlin]

The following article focus's on US spent fuel storage safety,

Several members of Congress are calling for the fuel to be moved from the pools into dry casks at a faster clip, noting that the casks are thought to be capable of withstanding an earthquake or a plane crash, they have no moving parts and they require no electricity.

but there is a reference to Fukishima's dry storage casks farther into the article.

But Robert Alvarez, a former senior adviser to the secretary of energy and expert on nuclear power, points out that unlike the fuel pools, dry casks survived the tsunami at Fukushima unscathed. “They don’t get much attention because they didn’t fail,” he said.

http://www.nytimes.com/2011/07/06/business/energy-environment/06cask.html?_r=2&pagewanted=1&ref=science

[Marlin]

Interesting piece of info.

In 1967, Tepco chopped 25 meters off the 35-meter natural seawall where the reactors were to be located, according to documents filed at the time with Japanese authorities. That little-noticed action was taken to make it easier to ferry equipment to the site and pump seawater to the reactors. It was also seen as an efficient way to build the complex atop the solid base of bedrock needed to better protect the plant from earthquakes.

But the razing of the cliff also placed the reactors five meters below the level of 14- to 15-meter tsunami hitting the plant March 11, triggering a major nuclear disaster resulting in the meltdown of three reactor cores.

http://online.wsj.com/article/SB10001424052702303982504576425312941820794.html

[navynukedoc]

Hind sight is 20/20 eh?

Are they still trying to get techs over there to clean up?

[navynukedoc]

Still?  Never heard that anyone was looking for "techs" to go to Japan and "clean up."  A few specialists have been recruited, but I haven't heard of a call out for "techs" (whatever those are).

I know Denuke had a posting shortly after the tsunami had rolled through there. I just haven't seen any more talk about it.

[HydroDave63]

I know Denuke had a posting shortly after the tsunami had rolled through there. I just haven't seen any more talk about it.

Thus, a lesson in body shops and resume stacks, grasshoppah....

[matthew.b]

Interesting piece of info.

In 1967, Tepco chopped 25 meters off the 35-meter natural seawall where the reactors were to be located, according to documents filed at the time with Japanese authorities. That little-noticed action was taken to make it easier to ferry equipment to the site and pump seawater to the reactors. It was also seen as an efficient way to build the complex atop the solid base of bedrock needed to better protect the plant from earthquakes.

But the razing of the cliff also placed the reactors five meters below the level of 14- to 15-meter tsunami hitting the plant March 11, triggering a major nuclear disaster resulting in the meltdown of three reactor cores.

http://online.wsj.com/article/SB10001424052702303982504576425312941820794.html

The part I put in bold is the key part.  You don't build nuclear plants on the overburden when bedrock is 25 meters away.  That's just not viable in earthquake country. 

[Marlin]

The part I put in bold is the key part.  You don't build nuclear plants on the overburden when bedrock is 25 meters away.  That's just not viable in earthquake country. 

Maybe 

Toyota was a key executive who was involved in the Fukushima No. 1 plant construction.

It is actually common practice to build primary nuclear plant facilities directly on bedrock because of the temblor factor.

Toyota also cited two other reasons for Tepco clearing away the bluff — seawater pumps used to provide coolant water needed to be set up on the ground up to 10 meters from the sea, and extremely heavy equipment, including the 500-ton reator pressure vessels, were expected to be brought in by boat.

In fact, Tepco decided to build the plant on low ground based on a cost-benefit calculation of the operating costs of the seawater pumps, according to two research papers separately written by senior Tepco engineers in the 1960s.

If the seawater pumps were placed on high ground, their operating costs would be accordingly higher.

"We decided to build the plant at ground level after comparing the ground construction costs and operating costs of the circulation water pumps," wrote Hiroshi Kaburaki, then deputy head of the Tepco's construction office at the Fukushima No. 1 plant, in the January 1969 edition of Hatsuden Suiryoku, a technical magazine on power plants.

Still, Tepco believed ground level was "high enough to sufficiently secure safety against tsunami and typhoon waves," wrote Seiji Saeki, then civil engineering section head of Tepco's construction office, in his research paper published in October 1967.

Engineers at Tohoku Electric Power Co., on the other hand, had a different take on the tsunami threat when the Onagawa nuclear plant was built in Miyagi Prefecture in the 1980s.

Like Fukushima, the plant was built along the Tohoku coast and was hit by tsunami as high as 13 meters on March 11.

Before building the plant, Tohoku Electric, examining historic records of tsunami reported in the region, conducted computer simulations and concluded the local coast could face tsumani of up to 9.1 meters.

Tohoku Electric had set the construction ground level at 14.8 meters above sea level — which barely spared the Onagawa plant from major damage from 13-meter-high tsunami that hit in March.

Former Tepco worker Naganuma said many locals now feel they have been duped by Tepco's long-running propaganda on the safety of its nuclear facilities, despite the huge economic benefits the plant brought to his hometown of Okuma, which hosts the Fukushima No. 1 plant.

[nukewood]

Why are we not hearing any updates on Japanese nuke problems, releases, affects on environment ,etc. ?

[wlrun3@aol.com]

The cores in the units in question have melted through their reactor pressure vessels and breached their drywells.

Anyone who has stood in a sub pile room or worked a torus or suppression pool must be wondering what this looks like.

[matthew.b]

I've never set foot in a BWR, but I'd love to see pictures of what the heck the state of things are in there.

[Marlin]

"The government should relax restrictions on the amount of allowable radiation in food and also rethink its evacuation criteria for Fukushima Prefecture, site of the world's worst nuclear accident since Chernobyl, a British physics professor said Monday.
"The real problem is fear," Oxford University professor emeritus Wade Allison said at the Foreign Correspondents' Club of Japan in Chiyoda Ward, Tokyo."

"The 500-becquerel limit on food sales imposed by the Japanese government is identical to the EU's limit but lower than the 1,200-becquerel limit set by the United States, which, Allison asserts, is also overly cautious."

http://search.japantimes.co.jp/cgi-bin/nn20111004a4.html

[Marlin]

"Three months after the start of full-scale water circulation system operations at the crippled Fukushima No. 1 Nuclear Power Plant, high-level radioactive waste has kept piling up amid no clear indications of its final disposal destination."

"The Kurion and Sally systems are designed to purify decontaminated water through an absorption unit called a "vessel" that contains zeolites. The vessel is changed every few days and the used vessels become radioactive waste.
 
Areva's water treatment system filters contaminated water by having sand absorb radioactive materials and precipitate with the help of chemicals. But the treatment produces highly polluted sludge.


According to TEPCO, radioactive waste as of Sept. 27 included 210 Kurion-made vessels (a total of about 307 cubic meters) with each vessel measuring 0.9 meters in diameter and 2.3 meters in height and 581 cubic meters of sludge via the Areva unit."

"Professor Akio Koyama at Kyoto University Research Reactor Institute says, "The density of high-level decontaminated water is believed to be a maximum 10 billion becquerels per liter, but if it is condensed to polluted sludge and zeolites, its density sometimes increases by 10,000 times. The density cannot be dealt with through conventional systems.""

http://mdn.mainichi.jp/mdnnews/news/20111003p2a00m0na011000c.html

[Marlin]

The operator of Japan's tsunami-hit Fukushima nuclear power plant Monday said the amount of radiation being emitted from the complex has halved from a month ago, in the latest sign that efforts to bring the plant under control are progressing.

http://www.reuters.com/article/2011/10/17/us-japan-nuclear-idUSTRE79C0PL20111017

[Marlin]

The government and the Tokyo Electric Power Co. (TEPCO) are expected to announce that they will aim for a stable condition called "cold shutdown" of the nuclear reactors at the crippled Fukushima No. 1 Nuclear Power Plant by the end of this year, slightly earlier than the originally planned deadline of mid-January.
 
The government will hold a meeting of its nuclear disaster taskforce as early as December to decide on whether they can call the "step 2" phase of the roadmap to bring the nuclear power plant under control finished. This "step 2" phase aims for "having the release of radioactive material under control and a sharp curb in radiation levels." The target period for achieving step 2 was set for "between mid-October and mid-January next year."
 
One condition for achieving a cold shutdown was having the temperature at the bottom of each reactor pressure vessel of the No. 1 to 3 nuclear reactors at the Fukushima plant under 100 degrees Celsius from the beginning of this month -- a condition currently being met. Furthermore, according to TEPCO, the amount of radioactive substances being released from the nuclear reactor buildings from Sept. 1 to Sept. 15 was about 200 million becquerels per hour, about one four-millionth of what was measured immediately after the outbreak of the nuclear crisis, and the amount of radiation on the outer premises of the nuclear plant's grounds is estimated to be at most 0.4 millisieverts per year, below the legal limit.



http://mdn.mainichi.jp/mdnnews/news/20111017p2a00m0na007000c.html

[wlrun3@aol.com]

What is the instrument on the tripod in these photos of the DOE RAP team set up at Fukushima?

http:// http://m.flickr.com/lightbox?id=6231181876

http://m.flickr.com/lightbox?id=6231181804

[Marlin]

First glimpses inside the Fukushima No. 1 compound since 3/11

http://www.japantimes.co.jp/text/nn20111117f1.html

http://www.japantimes.co.jp/images/photos2011/nn20111117f1/index.html

[tr]

Very detailed report from INPO (publically released) is available at the following link:

http://www.nei.org/resourcesandstats/documentlibrary/safetyandsecurity/reports/special-report-on-the-nuclear-accident-at-the-fukushima-daiichi-nuclear-power-station

[Cellman]

I read through the INPO report on Fukushima. Seems very complete and fact based, although it does a good job of putting people in the middle of the situation. I can only imagine hooking car batteries up to instruments to take RPV level readings and probing other insturments. The feeling of doom watching the water level fall must have been overwhelming.

One question comes to mind. Several chapters in the report refer to highly radioactive debris scattered about from the reactor building explosions. With the SFP's apparently intact, and the containments largely intact, where did all this radioactive material come from. Is there enough activated stuff up there to cause widespread contamination? Otherwise, are we looking at contamination from gaseous fission products that escaped with the hydrogen that built up in the RB?

Thanks!

[matthew.b]

Is there enough activated stuff up there to cause widespread contamination? Otherwise, are we looking at contamination from gaseous fission products that escaped with the hydrogen that built up in the RB?

Thanks!

At the levels they were talking about, it has to be the fission products going out with the vented steam and hydrogen as you're speculating.