(Correction: The previous estimate was 1 terabequerel per hour, not per day. So, per day would be 24 terabequerels.)
of radioactive iodine and cesium still spewing out of the plant, Japan's Nuclear Safety Commission now admits.
On April 12 during the joint press conference with Nuclear and Industrial Safety Agency (NISA) where they jointly announced the Fukushima I Plant accident was INES Level 7, the Commission assured the world that said that the release of radioactive materials from the plant had decreased to less than 1 terabecquerel per hour, or 24 terabecquerels per day.
It took the Commission 11 days to go from 24 terabecquerels per day to 154 terabecquerels per day. They say they miscalculated. What else have they, all nuclear experts, miscalculated?
From Yomiuri Shinbun (9:15PM JST 4/23/2011):
The Nuclear Safety Commission under the Prime Minister's Office disclosed on April 23 that the amount of radioactive materials being released from the TEPCO Fukushima I Nuclear Power Plant was 154 terabecquerels per day (1 tera is 1 trillion) as late as April 5 when the amount being released was considered stabilized.
On April 5, the estimated amount of radioactive materials released from Fukushima I Nuke Plant was 0.69 terabecquerels/hour for iodine-131 and 0.14 terabecquerels/hour for cesium-137. When the numbers were recalculated according to the INES method (converting cesium amount into iodine equivalent), the amount released turned out to be 6.4 terabecquerels/hour (which was 154 terabecquerels per day. Previously, the Nuclear Safety Commission had simply added the numbers for iodine-131 and cesium-137, and announced it was less than 1 terrabecquerel per hour.
５日に福島第一原発から大気に放出された放射性物質の推定値は、ヨウ素１３１が毎時０・６９テラ・ベクレル、セシウム １３７が同０・１４テラ・ベクレル。国際的な事故評価尺度（ＩＮＥＳ）で使われるヨウ素換算値で、ヨウ素とセシウムの合計量を計算し直すと、放出量は同 ６・４テラ・ベクレル（２４時間で１５４テラ・ベクレル）となることがわかった。同委員会はこれまで、５日ごろの放出量について、セシウムとヨウ素の量を 単純に合計し、「毎時約１テラ・ベクレル以下」と低く見積もっていた。
Hmmmm. The supposed nuclear power experts of the Committee didn't know how to calculate using the INES method? BS. Because on April 12 when they announced the total emission estimate of the radioactive materials from March 23 to April 5, they did say they converted the cesium amount into iodine equivalent.
Now, there's another interesting (but all too common by now) work of editing out some unpleasant information, no doubt practiced by the 4th column (the media) by themselves for the good of the community (no doubt). The earlier version of the same Yomiuri article (which I found on a Japanese message board) had the following sentence after where the current version ends:
If this amount [154 terabecquerels per day] continues to be released from the plant, it would be the equivalent of INES Level 6. [154 terabequerels per day for 90 days = 13,860 terabequerels.]３か月、この状態が続いた場合の放出量は、ＩＮＥＳの「レベル６」の事故に相当する。
You can simply calculate it yourself to come to the same conclusion, but for the majority of people who wouldn't bother, if they weren't told they wouldn't connect.
The earlier version also had this plausible deniability comment from the Commission that it was nothing more than "guesstimate" and no cause for alarm:
The Commission said "The amount that was being released [as of April 5] is only an estimate; it could have wide variance and fluctuations. The radiation level in the air around the Nuke Plant is slowly falling, and it is not the level that would have immediate [negative] effect on health."
Sure. It is "safe" unless people immediately develop cancer and radiation burn.
But wait, there may be more! (Ah it never ends...and it's taking me a very long time to even write up this post...)
Here's the Nuclear Safety Commission's estimate of the total release of radioactive materials as of April 5. Looking at the chart (I added the English explanation), they did seem to think that after the surge on March 15 and 16 (after the Reactors 3 and 4 explosions) the daily release was hardly more than 24 terabequerels; the lines went flat after March 23 or so:
If it has been 154 terabequerels per day instead of 24 since March 23, that's already additional 4,160 terabequerels by now, which alone would translate into the INES Level 5.
An INES Level 5 "accident" every month, Level 6 every 3 months? Slow and steady wins the race to pass the Chernobyl accident...