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はてなキーワード: over timeとは

2018-03-25

2018香港深圳広州の旅 Day.4

anond:20180324124847





Day.4


上晝


香港最後の夜は、一度夜中に目がさめるという自分にとっては日本でもお馴染みの睡眠だった。

昨日の広州行で程よく疲れたせいなのか、香港に慣れてきたからなのか。

慣れてきたとしても、今日が今回の香港旅行最後の日だ。


チェックアウトまで時間があるのでネイザンロード沿いの便利店でお土産いくつか買う。

レジオクトパスカードを出すと

「唔収◯×・・・

あ、使えないのか。今のはすぐにわかったぞ。

あんまり焦んなくなってきた。


しばらく散策していると、台湾でも見かけた誠品書店広告が。

しめた。本が買える。住所を検索して向かった。


晏晝


海岸沿いにある香港の誠品書店は、台湾と同じく綺麗でセンスのいい内装だった。

複雑な本はわからないので、今回も料理本かな?

いくつか物色していると、グラフと表が描かれた本があった。

多分、ポップミュージック音楽理論に関する本。

当然内容はわからない。でも妙に気になったので、買うことにした。


レジに持っていく。

「◯×◯×・・・

「a,我係日本人」

「oh, do you have shop card?」

「none」

初めてストレート意思疎通できた広東語が「私は日本人です」だとは。

教科書に載っているような表現でも意外に役に立つもんだ。

別のレジではショップバックの要無用についてジェスチャーで聞かれ、料理本も一緒に包んでもらった。


ホテルの部屋に戻ると、あれ、鍵が開かない。

「I can’t open dore at my room.」

「Check out time passed, you over time. check out time 12.」

しまった、2時と勘違いしてた。

そういやチェックインの時にヤケにゆっくりだなと思った。

鍵を開けてもらって、急いで荷物をまとめる。

ベッドにはメモを置いておいた。

「Thank you. I had a great time! 再見

ベットメイクの人とすれ違う。

「I had a great time.」

笑顔

エレベーターに駆け込んだ。


飛行場に向かうまで荷物を預かってもらう。

「Please keep my baggege.」

と言いながらメモを見せる。

「幫我在放我嘅行李到我去機場、可唔可以呀?」

にいちゃんメモをじっと見ている。

あれ、怪しい広東語書いたかな?と思ったが、どうやら彼は広東語がわからないようだった。

そうか、「外国人がやる仕事」ってのも歴然とあるのか。

「When are you coming back?」

「7 O,clock. take care.」


途中、腹が減ると具合が悪くなりそうなので、飲茶する事に。

「一位、唔該」

拭いているテーブルを指さされ

「乜嘢茶?」

「普洱、唔該」

注文シートを書いて

「落單、唔該」

シートを渡す。

想定していた問答なのでスムーズにできた。

高速な香港時間コミニュケーションできると気持ちがいい。


出てきたのは、

1.油で揚げたクレープのようなもの。オイリーでつけダレが美味い。

2.ガチョウが乗ったビーフンスウィートチリソースつき。香港ガチョウは表面を甘いタレでコーティングしてカリッとローストする。

3.ツミレ。貝かなにかのつけダレは少しくさみがあり塩辛い。

それと普洱茶。

ちょっといかな、と思ったけど、スルスルと食べられた。

「理單、唔該」

「ツァッサップツァッ」

「?」

メモを見せられる。

あ、$77か。

ちょっと詰まってしまった。

釣りは投げるように寄越されるが、気にしない。

ここは香港からね。


下晝


飛行場に向かうにはまだ早い。

まだ行っていないところに行こう。MTRで深水埗へ。

香港人による日本紹介動画によれば、日暮里日本の深水埗なのだという。

ということは、日暮里ぽいんだろう。


深水埗につくと、そこはたしかに今まで見ていたきれいなばかりの香港とちがって、露天などが立ち並ぶ下町風情だった。

でも日暮里よりはるかに賑やかだ、

日本人の印象であるカオス看板風景の「古き良き香港」はここじゃないかな。

OK.次は今回一切足を踏み入れなかった香港東側だ。


MTRを乗り継いで北角(ノースポイント)へ到着。

それにしても疲れてきた。

喫茶店で一息つこう。


喫茶店冷房香港っぽく引くほど強い。

「理單、唔該」

しまった、席に着くなり会計をお願いしてしまった。

気にせず注文を聞く先生

「coffe, ice

ドンッ!!しばらく待っていると景気良い音とともにコーヒーが現れた。

甘さが心地い。

でもちょっと寒いホットにすりゃよかった。

寒いしもう出るか。

「理單、唔該」

入店してから2回目の会計

ただし実際に払ったのは1回。

「洗手間邊度㗎?」

店の奥を指差される。

みんな、香港に行く時にはこの言葉は覚えておくんだ、絶対使うし、発音簡単だ。

トイレで用をたし、次の目的地、銅鑼湾コーズウェイベイ)に向かった。


MTRで向かおうと思ったけど、ちょっと街を行き交うトラム、2階建の路面電車に乗ってみる事にした。

オクトパスカードで乗れるらしいし、大丈夫だろう。


トラムに乗り2階に座る。

都合のいい事に、行き先は銅鑼湾らしい。

ここままトラムで向かおう。

しばらくすると、高齢のご婦人が入ってきた。

「座ります?」あんまり考えずに日本語が出た。

婦人は、笑顔で手を振りつつ

「唔該晒」

いいのか。

上げ掛けた腰を下ろす。

と前の若い女性が立ち上がると、ご婦人はそこに座った。

広東語では「おねがいします」も「どうも」も「いいですよ」も「きにしないで」も「すいません」も「唔該」なんで、ちょっとややこしい。


銅鑼湾は新旧の香港が入り混じったような繁華街だ。

白人もよく見かけるし、雰囲気西洋っぽい。

長身イケメン2人組が風船を配っていた。

Guy’s, I’m Foreigner. Can i take your photo?」

「Of course.」

「3,2,1, Shoot!」

「have a goot time ;)」

「Thank you!」

元同僚にみせよう。絶対イケメン好きだ(偏見)。


挨晩


予定より1時間ほど早いが、荷物を回収しよう。

ホテルに戻り「Mr,I want pick up my baggege.」

すぐに出てきた。

あれ、超重い。

これ持ってあの激混みのMTRに乗るのうんざりするなぁ。


というわけでタクシーを使う事にした。

「的士!」

「我想去機場」

通じない。

Hong Kong Airport.」

タクシーは滑り出し、人が歩いている小道を縫って走る。

おい怖いな。

大道に出ると、別の方向性で怖かった。

単純にスピードが速い。

アジアタクシーはこうだよね。


佐敦(ジョーダンから香港国際空港までは$230と少し。

釣りを渡される。

「For you.」

小銭を返した。

多分、香港で渡す最後チップだ。


夜晩


チェックインまで時間があったので、この日誌を書いていると、携帯電池が心もとない。

持ってきたモバイルバッテリーも閉店ガラガラ状態だ。

カウンターで尋ねる。

「I want carge Moba battery.」

「Phone?」

うなづく。

カウンターの裏側を指差された。

香港に来るまでは英語なんて全然ダメだと思っていたが、必要に迫られると喋れるものだ。

そうこうしているうちに帰りの便のチェックインが始まったので、済ませておこう。

チェックインを済ませたが、よくよく考えると、荷物重すぎないか

重量チェックの前でキャッキャウフフしているGirlsに困った顔で「Pleeease ><

やっぱ明らかに重量オーバーだ。

もう一度チェックインカウンターに。

「I want store my baggege.」


香港ドルからの再両替をどうしようかと思っていたが、タクシー結構でかく、手元には$55弱しか残っていなかった。

コーヒーチョコレートブラウニーで小腹を満たして$45。

綺麗に使ったもんだ。

チョコレートブラウニーの甘さで結構喉が渇いたが、オクトパスカードがまだ残っている。

セブンイレブンで水を買う。

カードを見せようとするやいなや、レジの小太りのお兄ちゃんが読み取り機をバンバンと叩いて示した。

どこの国にも手際が良すぎてちょっとコミカルな人というのはいものだ。

香港最速の決済だったかもしれない。


時刻は22:30。

ずいぶん早くチェックインをすませたために、ほとんど列に並ばなかった帰りの便のチェックインカウンターにも、人が集まって列をなしていた。

もう出国検査場に向かおう。


幼い時代の優しさとノスタルジー追体験したような昨年の台湾旅行と違い、今回の香港深圳広州旅行ちょっとした冒険感のある、エキサイティングものだった。

特に南洋華人の明るさと激しさには、自分の中のエネルギーを叩き起こされたような気がした。

この4日でイミグレーションの通過は4度目、もう慣れたものだ。

検査員の男性パスポート出国カードを出し、検査は何のトラブルもなく完了した。

最後にこの広東語だけは伝えたい。

「Ser, i had a great time.我好鐘意香港。」

年配の検査員は一瞬ぽかんとした顔をしたが、まあ付け焼き刃の広東語が通じなかったのは仕方ないか

深く気にせず手荷物検査に向かおうとすると、後ろから明るい声が響いた。

Hey! Also hong kong into come back!」

親指をあげて答える。

再見!」

2016-11-05

Communicating underwater is challenging.

Light and odors don't travel well, so it's hard for animals to see or smell.

But sound moves about four times faster in water than in air, so in this dark environment, marine mammals often rely on vocalization to communicate.

That's why a chorus of sounds fills the ocean.

Clicks, pulses, whistles, groans, boings, cries, and trills, to name a few.

But the most famous parts of this underwater symphony are the evocative melodies, or songs, composed by the world's largest mammals, whales.

Whale songs are one of the most sophisticated communication systems in the animal kingdom.

Only a few species are known to sing.

Blue, fin, bowhead minke whales, and of course humpback whales.

These are all baleen whales which use hairy baleen plates instead of teeth to trap their prey.

Meanwhile, toothed whales do use echolocation, and they and other species of baleen whales make social sounds, such as cries and whistles, to communicate.

But those vocalizations lack the complexity of songs.

So how do they do it?

Land mammals like us generate sound by moving air over our vocal chords when we exhale, causing them to vibrate.

Baleen whales have a U-shaped fold of tissue between their lungs and their large inflatable organs called laryngeal sacs.

We don't know this for sure because it's essentially impossible to observe the internal organs of a living, singing whale, but we think that when a whale sings, muscular contractions in the throat and chest move air from the lungs across the U-fold and into the laryngeal sacs, causing the U-fold to vibrate.

The resulting sound resonates in the sacs like a choir singing in a cathedral making songs loud enough to propagate up to thousands of kilometers away.

Whales don't have to exhale to sing.

Instead, the air is recycled back into the lungs, creating sound once more.

One reason whale songs are so fascinating is their pattern.

Units, like moans, cries, and chirps are arranged in phrases.

Repeated phrases are assembled into themes.

Multiple themes repeated in a predictable pattern create a song.

This hierarchical structure is a kind of grammar.

Whale songs are extremely variable in duration, and whales can repeat them over and over.

In one recorded session, a humpback whale sang for 22 hours.

And why do they do it?

We don't yet know the exact purpose, but we can speculate.

Given that the singers are males and they mostly sing during the mating season, songs might be used to attract females.

Or perhaps they're territorial, used to deter other males.

Whales return to the same feeding and breeding grounds annually, and each discrete population has a different song.

Songs evolve over time as units or phrases are added, changed, or dropped.

And when males from different populations are feeding within earshot, phrases are often exchanged, maybe because new songs make them more attractive to breeding females.

This is one of the fastest examples of cultural transmission, where learned behaviors are passed between unrelated individuals of the same species.

We can eavesdrop on these songs using underwater microphones called hydrophones.

These help us track species when sightings or genetic samples are rare.

For example, scientists have been able to differentiate the elusive blue whale's populations worldwide based on their songs.

But the oceans are getting noisier as a result of human activity.

Boating, military sonar, underwater construction, and seismic surveys for oil are occurring more often which may interfere with whale's communication.

Some whales will avoid key feeding or breeding grounds if human noise is too loud.

And humpback whales have been observed to reduce their singing in response to noise 200 kilometers away.

Limiting human activity along migratory routes and in other critical habitats, and reducing noise pollution throughout the ocean would help ensure whales continued survival.

If the whales can keep singing and we can keep listening, maybe one day we'll truly understand what they're saying.

2016-05-24

http://anond.hatelabo.jp/20160524151555

FRPライブラリサブタイトルに、 library that provides first class reactive value 'over time' と書かれている、これ拡張じゃないのか?

拡張なら「関数型的じゃない」っていわれたら「関数型を拡張してるから」って答えればいいだけの話

すでに出たサンプルからFRPの効力がまざまざと見せつけられている。

FRPの効力を否定なんて誰もしてない(よね)

「これが正しい関数型でお前らの状態渡しは間違ってる」みたいに言うから荒れる

間違っている電波

個人的電波だと思うのはこういう匿名書き込みを住井だ駱駝だ言い出すところ

いやだから、定数なんだから書き換わらないんだよ、FRPストリームconst 定数なんだから

ストリームから定数とか、過去の値保存してるから定数とか言ってみたところで、プログラム内の色んな関数から読み書きされる可能性があって誰が書き換えたか中身読まないとわからないんじゃ、グローバル変数使ってるプログラム欠点をそのまま持ってるじゃん

http://anond.hatelabo.jp/20160524145224

よーわからんw 岡部氏は、自作ライブラリHPで、

FRP純粋理想とする関数型+時間で変化するストリームを値にマップして扱うリアクティブプログラミングの組み合わせ

まり関数型の拡張っていうなら誰も反対無いと思うんだけど。

FRPライブラリサブタイトルに、 library that provides first class reactive value 'over time' と書かれている、これ拡張じゃないのか?

https://www.npmjs.com/package/timeengine

HaskellのIOモナドみたいな別の抽象化DISりつつ、FRPこそ正しい関数型みたいに言うから荒れるんじゃないの?

IOモナドDisってるのかどうかまでは知らない。しかし、すでに出たサンプルからFRPの効力がまざまざと見せつけられている。

荒れるのは自由だけど、両方正しいとかそういうのじゃなくて、間違っている電波だみたいな叩きしかなくて、要するに感情論で反対派は反発しているだけでOK?

あるよ。

関数がどのパラメータ依存して、何を結果として返すのか明確になる。

グローバルな値を参照したり書き換えたりしてたら、関数の中身読まないとわからなくなる。

短いプログラムならそれでもいいけどね。

別の誰かが書いてたように、上位スコープ内に定義されてるDOMでも、数学ライブラリでもなんでも、引数関数に渡すのか?

グローバルな値を参照したり書き換えたりして

いやだから、定数なんだから書き換わらないんだよ、FRPストリームconst 定数なんだから

関数型のわかりやす説明であって、住井派に反対してるとか、岡部路線とかじゃないよね、と。

オブジェクト指向と対比して考え方をまず学ぶって岡部路線、住井グループはそれを目の敵にしていて集団的攻撃している様をみたプログラミングコミュニティは逃げ、その後、不毛な大地のみが残った。

2016-04-14

detox

Toxins are everywhere. Car exhaust, secondhand smoke, flame retardants, plastic packaging, heavy metals, pesticides, BPA-coated receipts… Unless you’re living in virgin forest, you’re going to come into contact with some less-than-optimal chemicals pretty much every day.

That’s definitely no reason to panic. In fact, small doses of toxins may be good for you because of a phenomenon called hormesis – mild stress makes your cells work more efficiently. However, your body can have trouble clearing certain toxins. You eliminate most of the bisphenol-A (BPA) and other plastics you ingest, but a small percentage hides away in your fat cells, messing with your hormones and accumulating over time. It’s the same deal with several mold toxins, heavy metals like lead, nickel, cadmium, mercury, and aluminum, and with certain pharmaceuticals and drugs like THC.

A good detox protocol can help you eliminate these more stubborn toxins. The trouble is that many common detoxes don’t work. Juice and water cleanses, for example, are often actually counterproductive because they deprive your body of essential nutrients it needs to function. That said, there are a few genuine ways to detox.

Because so many toxins stay in your fat cells, one way to detox is through lipolysis – breaking down your fat cells and releasing the hard-to-reach toxins stored within them. Lipolysis is especially effective when you combine it with liver and kidney support or adsorbents that can suck up the released toxins. This article focuses on all of the above. Let’s start with saunas.

1) Sauna sessions

Sweating does more than cool you off. It also helps you get rid of both heavy metals and xenobiotics – foreign compounds like plastics and petrochemicals – in small but significant amounts. A 2012 review of 50 studies found that sweating removes lead, cadmium, arsenic, and mercury, especially in people with high heavy metal toxicity [1]. Another study put participants in both traditional and infrared saunas and found similar results [2]. Sweating also eliminates hormone-disrupting BPA, which accumulates in your fat cells [3].

There’s debate about the best kind of sauna for detoxification. A couple studies have shown that infrared saunas are the most effective for detoxing, but the research was funded by infrared sauna companies, so the results are questionable. Both traditional and infrared saunas are effective for detoxing [2]. That said, I prefer infrared saunas for a few reasons:

They don’t get as hot. Traditional saunas heat the air around you, while infrared light penetrates and heats your tissue directly. You sweat in an infrared sauna at around 130-150 degrees instead of at 180-200 degrees, so you can stay in for longer without feeling like you’re going to pass out. I’ve done 2-hour infrared sauna sessions (drinking salt water the whole time to replenish electrolytes and fluids, of course).

They’re easier on your electric bill. Again, infrared saunas require less energy, especially if you get a sauna that reflects infrared light back on you. This one, for example, costs about 15 cents an hour to run.

Infrared saunas are often cheaper.

I personally use a Sunlighten infrared sauna and love it. If you don’t want to buy an infrared sauna and there isn’t one around you, a standard sauna will work perfectly well [2]. There’s probably one in your local gym.

Keep in mind that sweating pulls electrolytes and trace minerals from your body, so it’s important to drink a lot of fluids and get plenty of salt (preferably Himalayan pink salt or another mineral-rich natural salt) if you’re going to use a sauna to detox [2].

2) Exercise

Exercise is another way to flush toxins from your body, and through more than just making you sweat. Exercise increases lipolysis (the breakdown of fat tissue), releasing toxins stored in your fat tissue. Studies show that people who exercise and lose body fat end up with higher levels of circulating hormone disruptors [4]. Increasing lipolysis through diet does the same thing [5].

Mobilizing toxins isn’t necessarily a good thing, particularly if you’re unequipped to get rid of them. You want to be sure you’re getting rid of toxins, not just moving them to a different part of your body. Working out addresses the issue to a degree: it improves circulation, providing more oxygen to your liver and kidneys so they can better filter out toxins. You can also give your system even more support and pull out bad stuff with the next two detox tools: activated charcoal and glutathione.

3) Activated charcoal

Activated charcoal is a form of carbon that has massive surface area and a strong negative charge. It’s been around for thousands of years and it’s still used in emergency rooms today to treat poisoning.

Charcoal binds to chemicals whose molecules have positive charges, including aflatoxin and other polar mycotoxins [6], BPA [7], and common pesticides [8]. Once the chemicals attach to the charcoal you can pass them normally (i.e. poop them out).

Charcoal can bind to the good stuff, too, so I don’t recommend taking it within an hour of other supplements. Try taking a couple charcoal pills along with exercise or have a sauna session. They should adsorb many of the toxins you release into your gut and GI tract.

4) Glutathione

Glutathione is a powerful antioxidant that protects you from heavy metal damage, according to studies in both human and rat cells [9,10,11,12]. Glutathione also supports liver enzymes that break down mold toxins and heavy metals. Your digestion will destroy normal glutathione, so opt for a liposomal glutathione supplement that makes it through your stomach. You can also supplement with N-acetylcysteine and alpha-lipoic acid, which your body can use to build glutathione on its own [13]. If you have severe heavy metal or mycotoxin poisoning, talk to a naturopath or functional medicine doctor about intravenous (IV) glutathione. It’s expensive and less convenient than an oral supplement, but it works very well.

5) Cryolipolysis

We’ve talked about how heat and exercise can increase fat burning to detox your fat cells. It turns out cold can do the same. Cryochambers are gaining popularity with professional athletes and other high performers for their ability to quell inflammation. It turns out they can help you burn fat – and release the toxins stored in itas well.

A cryochamber uses liquid nitrogen to supercool your body, stimulating mitochondrial function and decreasing inflammation. Intense cold also destroys fat cells, which has led to cryolipolysis therapy as a way to slim down [14,15]. You can use it to detox, too.

Can’t get your hands on a cryochamber? Try traditional cold thermogenesis instead.

6) Ketosis

Quick disclaimer: I haven’t found studies specifically looking at ketosis and toxin load, so you may want to take this section with a grain of (Himalayan) salt. That said, ketosis is a very effective way to induce lipolysis, particularly if you’re fasting.

When you’re in ketosis and you haven’t eaten recently, your body breaks down your fat stores into free fatty acids, which it then converts to ketones for fuel. That means that, in theory, you should be able to supercharge your detox (and fat loss) by dropping into nutritional ketosis.

The Bulletproof Diet puts you into mild ketosis, which curbs your hunger and sharpens your brain without forcing you to forego carbs entirely. If you want to try nutritional ketosis for detoxing, youll have to modify the Bulletproof Diet slightly. Skip carb reefed days for a couple weeks and limit carbs to ~30-50 grams per day. You can use keto urine strips or – even better – a blood ketone meter to test and make sure you’re becoming fat-adapted. Once your levels read around 1.5 mg/dL, you’re comfortably in nutritional ketosis. At that point, fasting will attack your fat stores and mobilize toxins, which you can mop up with activated charcoal or sweat out (or both).

7) Chelation therapy for heavy metals

Chelation therapy is the strongest way to detox heavy metals. It can also be dangerous, so many doctors don’t recommend it unless you have moderate to severe heavy metal poisoning. Chelation therapy uses compounds called chelators that form strong bonds with heavy metals, leaving them unable to further poison your body. You can then pass them normally. Chelation therapy is very effective for removing lead, mercury, aluminum, arsenic, iron, and copper.

If you’ve been exposed to a lot of heavy metals, talk to a functional medicine doctor about chelation therapy. You really want to go to a medical professional for this one, because it’s so effective that if your liver and kidneys aren’t able to process the metals (a common problem in people with heavy metal poisoning) you can get seriously ill.

Combining detox methods for maximum effect

Each of these 7 methods works well on its own, and you can stack methods for an even greater effect. Exercise and sauna sessions are a good example. Preliminary evidence suggests that exercising and then hitting the sauna afterward will detoxify you better than either one alone does [16]. With that in mind, here’s a sample detox protocol:

Take 2-3 mL liposomal glutathione and 2-3 g vitamin C an hour before exercising.

Exercise for at least 20-30 minutes (HIIT is a good option).

Take 3-4 activated charcoal pills.

Spend 45-60 minutes in a sauna. Remember to get plenty of water and salt/electrolytes.

If you have a lot of fat and you’re burning it off quickly, you’re probably getting rid of a lot of toxins in one fell swoop, and you may get a headache, digestive problems, brain fog, etc. If that happens try taking more glutathione, vitamin C, and charcoal. Be sure you take charcoal at least an hour away from other supplements, as it binds to vitamin C.

Toxins are a fact of modern life, especially if you live in a city or somewhere with poor air quality, mold, and/or a lot of petrochemical byproducts. These detox methods can give your body a little extra support dealing with pollutants and help you perform your best.

Subscribe below if you want more info about how to upgrade your body and brain. Thanks for reading and have a great week!

2011-03-14

福島原子力発電所CNNコメント欄 MIT科学者見解2【東日本巨大地震

When the diesel generators were gone, the reactor operators switched to emergency battery power. The batteries were designed as one of the backups to the backups, to provide power for cooling the core for 8 hours. And they did.

Within the 8 hours, another power source had to be found and connected to the power plant. The power grid was down due to the earthquake. The diesel generators were destroyed by the tsunami. So mobile diesel generators were trucked in.

This is where things started to go seriously wrong. The external power generators could not be connected to the power plant (the plugs did not fit). So after the batteries ran out, the residual heat could not be carried away any more.

At this point the plant operators begin to follow emergency procedures that are in place for a “loss of cooling event”. It is again a step along the “Depth of Defense” lines. The power to the cooling systems should never have failed completely, but it did, so they “retreat” to the next line of defense. All of this, however shocking it seems to us, is part of the day-to-day training you go through as an operator, right through to managing a core meltdown.

It was at this stage that people started to talk about core meltdown. Because at the end of the day, if cooling cannot be restored, the core will eventually melt (after hours or days), and the last line of defense, the core catcher and third containment, would come into play.

But the goal at this stage was to manage the core while it was heating up, and ensure that the first containment (the Zircaloy tubes that contains the nuclear fuel), as well as the second containment (our pressure cooker) remain intact and operational for as long as possible, to give the engineers time to fix the cooling systems.

Because cooling the core is such a big deal, the reactor has a number of cooling systems, each in multiple versions (the reactor water cleanup system, the decay heat removal, the reactor core isolating cooling, the standby liquid cooling system, and the emergency core cooling system). Which one failed when or did not fail is not clear at this point in time.

So imagine our pressure cooker on the stove, heat on low, but on. The operators use whatever cooling system capacity they have to get rid of as much heat as possible, but the pressure starts building up. The priority now is to maintain integrity of the first containment (keep temperature of the fuel rods below 2200°C), as well as the second containment, the pressure cooker. In order to maintain integrity of the pressure cooker (the second containment), the pressure has to be released from time to time. Because the ability to do that in an emergency is so important, the reactor has 11 pressure release valves. The operators now started venting steam from time to time to control the pressure. The temperature at this stage was about 550°C.

This is when the reports about “radiation leakage” starting coming in. I believe I explained above why venting the steam is theoretically the same as releasing radiation into the environment, but why it was and is not dangerous. The radioactive nitrogen as well as the noble gases do not pose a threat to human health.

At some stage during this venting, the explosion occurred. The explosion took place outside of the third containment (our “last line of defense”), and the reactor building. Remember that the reactor building has no function in keeping the radioactivity contained. It is not entirely clear yet what has happened, but this is the likely scenario: The operators decided to vent the steam from the pressure vessel not directly into the environment, but into the space between the third containment and the reactor building (to give the radioactivity in the steam more time to subside). The problem is that at the high temperatures that the core had reached at this stage, water molecules can “disassociate” into oxygen and hydrogen – an explosive mixture. And it did explode, outside the third containment, damaging the reactor building around. It was that sort of explosion, but inside the pressure vessel (because it was badly designed and not managed properly by the operators) that lead to the explosion of Chernobyl. This was never a risk at Fukushima. The problem of hydrogen-oxygen formation is one of the biggies when you design a power plant (if you are not Soviet, that is), so the reactor is build and operated in a way it cannot happen inside the containment. It happened outside, which was not intended but a possible scenario and OK, because it did not pose a risk for the containment.

So the pressure was under control, as steam was vented. Now, if you keep boiling your pot, the problem is that the water level will keep falling and falling. The core is covered by several meters of water in order to allow for some time to pass (hours, days) before it gets exposed. Once the rods start to be exposed at the top, the exposed parts will reach the critical temperature of 2200 °C after about 45 minutes. This is when the first containment, the Zircaloy tube, would fail.

And this started to happen. The cooling could not be restored before there was some (very limited, but still) damage to the casing of some of the fuel. The nuclear material itself was still intact, but the surrounding Zircaloy shell had started melting. What happened now is that some of the byproducts of the uranium decay – radioactive Cesium and Iodine – started to mix with the steam. The big problem, uranium, was still under control, because the uranium oxide rods were good until 3000 °C. It is confirmed that a very small amount of Cesium and Iodine was measured in the steam that was released into the atmosphere.

It seems this was the “go signal” for a major plan B. The small amounts of Cesium that were measured told the operators that the first containment on one of the rods somewhere was about to give. The Plan A had been to restore one of the regular cooling systems to the core. Why that failed is unclear. One plausible explanation is that the tsunami also took away / polluted all the clean water needed for the regular cooling systems.

The water used in the cooling system is very clean, demineralized (like distilled) water. The reason to use pure water is the above mentioned activation by the neutrons from the Uranium: Pure water does not get activated much, so stays practically radioactive-free. Dirt or salt in the water will absorb the neutrons quicker, becoming more radioactive. This has no effect whatsoever on the core – it does not care what it is cooled by. But it makes life more difficult for the operators and mechanics when they have to deal with activated (i.e. slightly radioactive) water.

But Plan A had failed – cooling systems down or additional clean water unavailable – so Plan B came into effect. This is what it looks like happened:

In order to prevent a core meltdown, the operators started to use sea water to cool the core. I am not quite sure if they flooded our pressure cooker with it (the second containment), or if they flooded the third containment, immersing the pressure cooker. But that is not relevant for us.

The point is that the nuclear fuel has now been cooled down. Because the chain reaction has been stopped a long time ago, there is only very little residual heat being produced now. The large amount of cooling water that has been used is sufficient to take up that heat. Because it is a lot of water, the core does not produce sufficient heat any more to produce any significant pressure. Also, boric acid has been added to the seawater. Boric acid is “liquid control rod”. Whatever decay is still going on, the Boron will capture the neutrons and further speed up the cooling down of the core.

The plant came close to a core meltdown. Here is the worst-case scenario that was avoided: If the seawater could not have been used for treatment, the operators would have continued to vent the water steam to avoid pressure buildup. The third containment would then have been completely sealed to allow the core meltdown to happen without releasing radioactive material. After the meltdown, there would have been a waiting period for the intermediate radioactive materials to decay inside the reactor, and all radioactive particles to settle on a surface inside the containment. The cooling system would have been restored eventually, and the molten core cooled to a manageable temperature. The containment would have been cleaned up on the inside. Then a messy job of removing the molten core from the containment would have begun, packing the (now solid again) fuel bit by bit into transportation containers to be shipped to processing plants. Depending on the damage, the block of the plant would then either be repaired or dismantled.

Now, where does that leave us?

・The plant is safe now and will stay safe.

Japan is looking at an INES Level 4 Accident: Nuclear accident with local consequences. That is bad for the company that owns the plant, but not for anyone else.

・Some radiation was released when the pressure vessel was vented. All radioactive isotopes from the activated steam have gone (decayed). A very small amount of Cesium was released, as well as Iodine. If you were sitting on top of the plants’ chimney when they were venting, you should probably give up smoking to return to your former life expectancy. The Cesium and Iodine isotopes were carried out to the sea and will never be seen again.

・There was some limited damage to the first containment. That means that some amounts of radioactive Cesium and Iodine will also be released into the cooling water, but no Uranium or other nasty stuff (the Uranium oxide does not “dissolve” in the water). There are facilities for treating the cooling water inside the third containment. The radioactive Cesium and Iodine will be removed there and eventually stored as radioactive waste in terminal storage.

・The seawater used as cooling water will be activated to some degree. Because the control rods are fully inserted, the Uranium chain reaction is not happening. That means the “main” nuclear reaction is not happening, thus not contributing to the activation. The intermediate radioactive materials (Cesium and Iodine) are also almost gone at this stage, because the Uranium decay was stopped a long time ago. This further reduces the activation. The bottom line is that there will be some low level of activation of the seawater, which will also be removed by the treatment facilities.

・The seawater will then be replaced over time with the “normal” cooling water

・The reactor core will then be dismantled and transported to a processing facility, just like during a regular fuel change.

Fuel rods and the entire plant will be checked for potential damage. This will take about 4-5 years.

・The safety systems on all Japanese plants will be upgraded to withstand a 9.0 earthquake and tsunami (or worse)

・I believe the most significant problem will be a prolonged power shortage. About half of Japan’s nuclear reactors will probably have to be inspected, reducing the nation’s power generating capacity by 15%. This will probably be covered by running gas power plants that are usually only used for peak loads to cover some of the base load as well. That will increase your electricity bill, as well as lead to potential power shortages during peak demand, in Japan.

If you want to stay informed, please forget the usual media outlets and consult the following websites:

http://www.world-nuclear-news.org/RS_Battle_to_stabilise_earthquake_reactors_1203111.html

http://bravenewclimate.com/2011/03/12/japan-nuclear-earthquake/

http://ansnuclearcafe.org/2011/03/11/media-updates-on-nuclear-power-stations-in-japan/

 
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