Saturday, April 23, 2011

#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)

2 comments:

Robbie 001 said...

OK, it is official Tokyo is boned!

When are these guys going to learn to stop counting their eggs before they are hatched? Fukushima has been one long litany of proclamations of hope being dashed. Every time an official says something is "impossible" or "unlikely" we find out they are wrong. The ink on TEPCO's "roadmap" is barely dry and officials are already acting like everything is getting better and Tokyo is safe. There is still plenty of time and opportunity for a major mishap after the seasonal winds change direction. I just saw a program on NHK yesterday that talked about the increase in earthquakes aftershocks in the effected region will probably go on for years. An intact NPP may be designed to withstand earthquakes but how well can the blast effected buildings endure the aftershocks? It really makes me wonder if this is this causing the concern in SPF#4's structural integrity? If TEPCO says the after shocks didn't cause any new damage it is only because they don't know the full extent of the damage in the first place.

"There is no way Tokyo or Kyoto will come into harm's way," Mr. Hosono said in an interview with The Wall Street Journal on Saturday."

http://online.wsj.com/article/SB10001424052748703567404576281000490406640.html

This is like someone falling in a deep ravine and breaking both arms and legs saying, "well at least the bleeding has stopped I'll be out of here in a jiffy now that I have a roadmap to recovery". "First all I need to do is fashion some splints for my shattered limbs with my shattered limbs and I'll be well on my way".

arevamirpal::laprimavera said...

WSJ thinks he's a special advisor? Hahaha. He is an assistant of Kan, who recently remarked "we didn't feel like announcing" the meltdown.

What a joke. A punk like this is representing the country.

Post a Comment