#Radiation from Fukushima I Nuke Plant: It Was 850,000 Terabecquerels, NISA Now Says, and Not 370,000

In April when it nonchalantly raised the INES level of Fukushima I Nuclear Plant accident to "Level 7", the Nuclear and Industrial Safety Agency (NISA) said the total amount of radioactive materials (iodine and cesium) released into the atmosphere from the plant was 370,000 terabequerels.

Now it's been revised to 850,000 terabecquerels, 130% jump from 370,000.

Why the revision? NISA says it underestimated the release from the Reactors 2 and 3.

And remember, the contaminated water at Fukushima I Nuke Plant contains 720,000 terabecquerels of radioactive iodine and cesium.

Slowly and steadily approaching Chernobyl.

From Mainichi Shinbun English (6/7/2011):

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.

The Cabinet Office's Nuclear Safety Commission of Japan (NSC) had estimated that the total level of radioactivity stood at around 630,000 terabecquerels, but this figure was criticized as an underestimation. NISA officials plan to present the new figure at a ministerial meeting of the International Atomic Energy Agency (IAEA) after reporting it to the NSC.

The NSC and NISA, which operates under the Ministry of Economy, Trade and Industry, announced a figure for the total amount of radioactivity on April 12, when the severity of the Fukushima nuclear crisis on the International Nuclear Events Scale was raised to level 7, matching that of the Chernobyl nuclear accident. In the Chernobyl accident, the total amount of radioactivity reached 5.2 million terabecquerels.

The NSC calculated the amount of radioactive materials released into the air between the outset of the crisis and April 5, based on the amount of radiation from measurements taken near the plant. NISA based its calculations on the state of the plant's reactors.

The latest figure takes into consideration the release of radioactive materials during explosions at the plant's No. 2 and 3 reactors. The INES scale designates leaks of tens of thousands of terabecquerels as level 7 events, and the seriousness of the disaster on the scale will not change as a result of NISA's revision of the amount.

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720,000 Terabecquerels of Radioactive Materials in 100,000 Tonnes of Contaminated Water

When I posted the news about 100,000 tonnes of highly contaminated water at Fukushima I Nuke Plant, I forgot to mention this. (You can read about it in the Businessweek article here.)

That water is estimated to contain 720,000 terabecquerels of radioactive iodine and cesium.

That's another "Level 7" right there.

That's more than what has been released into the atmosphere, which the Nuclear Safety Commission estimates to be about 630,000 terabecquerels and Nuclear and Industrial Safety Agency estimates to be about 370,000 terabecquerels.

I personally think this air radiation numbers underestimate the true numbers, particularly the number from NISA. At that time (mid April), NISA said they calculated the number based on the amount of radioactive materials they estimated to be still inside the RPV. At that time, NISA assured everyone that the fuel rods were only partially damaged and they were all inside the Reactor Pressure Vessels. Now we know (and they should have known) that the RPVs were breached very early in the accident, and the melted core had at least partially escaped out of the RPV by the time they made the estimate.

Now, Fukushima is slowly approaching Chernobyl.

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Containment Vessels of Reactors 1, 2, 3 Were Possibly Damaged Within 24 Hours of March 11 Earthquake

Someone at Yomiuri Shinbun who was made to read the TEPCO's report to the Nuclear and Industrial Safety Agency (NISA), the government overseer, found this bit of information in the main report (225 pages, in Japanese; English translation is on-going at TEPCO): Containment Vessels were damaged within 24 hours of the quake.

It is not in the summary slides (10 slides, in Japanese), which I did read. In the TEPCO's press conferences since May 15, Matsumoto never admitted to the Containment Vessel damage but he didn't deny it either. He specifically said in a press conference I watched that he "cannot deny the possibility of the Containment Vessel having been damaged." (I will link my post reporting that if I ever retrieve it; Google deleted it in their "maintenance".)

Looks like a fun reading. I will report back when I see the exact words from TEPCO on the subject.

It's also amusing to see the Japan's MSMs now use the word "core meltdown (炉心溶融) quite often, which was a taboo word for 2 months until TEPCO officially admitted it on May 15.

Yomiuri Shinbun (9:53PM JST 5/24/2011):

　東京電力が福島第一原子力発電所の炉心溶融（メルトダウン）について詳しいデータ解析を行った結果、１～３号機では、圧力容器だけではなく、その外側を覆う鋼鉄製の格納容器も、地震後２４時間以内に損傷していた可能性があることが分かった。

It's been revealed that the steel Containment Vessels of the Reactors 1, 2 and 3 that house the Reactor Pressure Vessels (RPV) may have been damaged within 24 hours after the earthquake on March 11, according to the detailed analysis of the core meltdown at Fukushima I Nuclear Power Plant by TEPCO.

　解析結果の報告書は２３日に経済産業省原子力安全・保安院に提出された。

The result of the analysis was compiled into a report and submitted to the Ministry of Economy and Industry's Nuclear and Industrial Safety Agency on May 23.

　原子炉の運転データなどに基づいて地震後の状況を詳しく計算したところ、１号機は緊急冷却装置の「非常用復水器」が十分に働かず、炉心溶融の進行によって、地震後１５時間で圧力容器の底部が破損したことがわかった。底部には制御棒や中性子計測装置の貫通部が多数あり、強度の弱い溶接部分などが壊れて、溶けた燃料を含む高濃度汚染水が漏れ出したとみられる。

The detailed calculation of the reactors' operation data after the earthquake revealed that the bottom of the Reactor 1 RPV was broken after 15 hours after the earthquake because the emergency core cooling system didn't function well and the fuel started to melt down. There are many openings through which the control rods and the neutron measurement device goes through. The welded parts at the bottom, which do not have the same strength as the other part of the RPV, broke, and highly contaminated water that included the melted fuel may have leaked from there, according to the report.

I've been thinking about the "Level 7" designation of the Fukushima I Nuke Plant accident. When the NISA announced "Level 7", they were still publicly (at least) assuming that the majority of the fuel rods were more or less intact and inside the RPVs; that the RPVs were intact, and the Containment Vessels were intact, except for the Reactor 2 (the Suppression Chamber was damaged).

So, is it more likely now, that far more radioactive materials have escaped the reactors than the NISA or the Nuclear Safety Commission calculated? "Don't worry it's only 1/10 of Chernobyl" was another lie?

Or, were their calculations based on the secret knowledge that the RPVs and Containment Vessels were broken in the very early stage of the accident?

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Hilarity of the Day No.2: NY Post "Russia's nuclear chief says Japan exaggerating Fukushima crisis"

in order to give a break to the insurance companies, says Sergei Kiriyenko, the head of Russia's state nuclear agency Rosatom.

From New York Post (4/26/2011):

SANYA, China -- The disaster at the Fukushima atomic power plant cannot be compared to Chernobyl, Russia's nuclear chief said Wednesday, suggesting that Tokyo was exaggerating the emergency possibly for financial reasons.

"It is hard for me to assess why the Japanese colleagues have taken this decision," Sergei Kiriyenko, the head of Russia's state nuclear agency Rosatom, told reporters in the southern Chinese city of Sanya on the eve of the BRICS summit. "I suspect this is more of a financial issue than a nuclear one."

Earlier this week Japan upgraded its month-old nuclear emergency to a maximum seven on an international scale of atomic crises, placing it on a par with the Chernobyl disaster in 1986. Kiriyenko appeared to suggest that the Japanese authorities were seeking to reduce the burden on insurance companies.

Kiriyenko added that at first the Japanese authorities had thought to downplay the scale of the disaster but now the situation at the plant was improving.

"Our estimates have shown that the level was between five and six," Kiriyenko said. "Today it doesn't reach the sixth level."

France's nuclear safety agency also said this week that the impact of the Fukushima accident was not comparable to the Chernobyl disaster.

Fukushima has had three reactors that have hit problems, compared with one at Chernobyl.

But the Japanese plant has released only one-tenth of the radioactivity disgorged by Chernobyl because its reactor vessels have so far remained intact, thus keeping almost all of the nuclear fuel enclosed.

The previous rating of five had placed the unfolding disaster at the tsunami-hit Fukushima plant northeast of Tokyo on the same level as the 1979 Three Mile Island accident in Pennsylvania.

Level seven of the UN's International Nuclear Events Scale describes events with "major release of radioactive material with widespread health and environmental effects, requiring implementation of planned and extended countermeasures.

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#Fukushima I Nuke Plant: NISA Thought It Was Level 3 "Incident"

保安院、最初はレベル３。Talk about bureaucratic understatement.

From Asahi Shinbun (3:01PM JST 4/23/2011; translation is mine):

[Asahi Shinbun has learned that ] METI's Nuclear and Industrial Safety Agency's initial provisional assessment of the Fukushima I Nuclear Power Plant accident was INES Level 3. Level 3 is not an "accident" but an "incident" ["serious incident"]. It shows NISA's initial assessment was too optimistic.

NISA announced on the press conference on March 12 evening that the Fukushima I accident was an INES Level 4 "accident" ["accident with local consequence"]. Later, the level was raised to Level 7, the same as the Chernobyl accident in the former Soviet Union.

NISA's Level 3 assessment was made 10 hours after the earthquake, at 12:30AM on March 12. At that time, due to the earlier earthquake and tsunami, neither the external power nor the emergency power was available for Fukushima I's Reactors 1 through 3, and Fukushima II's Reactors 1, 2 and 4 and the cooling systems for the reactors were lost.

Two and a half hours later, venting of the steam that contained radioactive materials was announced for Fukushima I Nuke Plant. By then, radioactive materials must have been already leaking through pipes connected to the Reactor Pressure Vessel [of the Reactor 1?], and at 6:00AM on March 12 the radiation level inside the central control room shot up 1,000-fold.

NISA raised the level to Level 5 ["accident with wider consequences"] on March 18, the same level as the Three Mile Island accident, and on April 12 raised it again to Level 7 ["major accident"], the same level as the Chernobyl accident.

There are 8 INES Levels (0 to 7). The basic procedure is to make a provisional assessment within 24 hours of the accident and report to IAEA.

Kenji Sumita, professor emeritus at Osaka University thinks it is difficult to evaluate an on-going accident. As to NISA's initial assessment of Level 3, "In retrospect, it may show that [NISA] didn't quite understand the true situation," he says.

経済産業省原子力安全・保安院が、福島第一原子力発電所の事故について、事故やトラブルの深刻さを示す国際原子力事象評価尺度（ＩＮＥＳ）で当初は 「レベル３」と暫定評価していたことがわかった。レベル３は「事故」ではなく「事象」に分類される。保安院の初動の認識が甘かったことを示した。

　保安院は３月１２日夜の記者会見でＩＮＥＳで「事故」にあたるレベル４と発表した。その後、旧ソ連チェルノブイリ原発事故に匹敵する最高のレベル７にまで引き上げられた。

　レベル３の評価は地震発生から約１０時間後の３月１２日午前０時半の段階。福島第一１～３号機、福島第二１、２、４号機について地震と津波の影響で、外部電源も非常用電源も使えなくなっており、原子炉から熱を除く機能が失われたことから評価した。

　その２時間半後には福島第一原発で放射性物質を含む蒸気を外部へ放出する排気（ベント）の方針が発表された。このころ、すでに原子炉につながる配管の隙 間などから放射性物質が外部に漏れ出していたとみられ、１２日午前６時には中央制御室の放射線量が通常の１千倍に上がったと公表された。

　保安院は３月１８日に米国スリーマイル島原発事故に相当するレベル５、４月１２日に旧ソ連チェルノブイリ原発事故と同じレベル７に暫定評価を引き上げた。

　ＩＮＥＳはレベルが０～７まで８段階ある。トラブル発生後、２４時間以内に暫定評価して国際原子力機関（ＩＡＥＡ）に報告するのが原則的なルールだ。

　住田健二・大阪大名誉教授は「進行中の事故を評価するのは難しい」としたうえで、当初レベル３とした評価について「今からふりかえってみれば、認識が甘かった証しなのではないか」と話している。（小堀龍之）

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#Fukushima I Nuke Plant: Maybe a Level 7 Disaster

Kyodo News (in Washington, 3/15/2011):

The situation at the quake-hit Fukushima No. 1 nuclear plant in northeastern Japan ''has worsened considerably,'' the Institute for Science and International Security said in a statement released Tuesday.

Referring to fresh explosions that occurred earlier in the day at the site and problems in a pool storing spent nuclear fuel rods, the Washington-based think tank said, ''This accident can no longer be viewed as a level 4 on the International Nuclear and Radiological Events scale that ranks events from 1 to 7.''

Noting that a level 4 incident involves ''only local radiological consequences,'' it said the ongoing crisis is ''now closer to a level 6, and it may unfortunately reach a level 7'' -- a worst case scenario with extensive health and environmental consequences.

''The international community should increase assistance to Japan to both contain the emergency at the reactors and to address the wider contamination. We need to find a solution together,'' it said.

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