The radiation readings inside unit 1′s containment were unexpectedly low. It would be impossible to have the bulk of the melted fuel inside unit 1′s containment with those low radiation levels.
Unit 1 [containment vessel] appeared very black and charred, with a light amount of steam and condensation
The charred appearance could be a sign of some sort of explosive event inside containment.
The hydrogen explosion of unit 1 could have occurred in locations beyond just the refueling floor. This would explain the charred appearance of the containment structure and possibly some of the damage found inside so far.
The radiation readings in containment, around the building and in the torus room taken together point to the east side torus room as the general location of the melted fuel. With this being the case, TEPCO’s decommissioning plan will need to be changed. It also causes more concerns about radiation and contaminated substance releases from the plant. What is unknown at this point is if the fuel could have traveled further down inside the torus room that only has 2.7 meters of concrete foundation, or further laterally through the wall or openings between the torus room and other interconnected rooms between the reactor building and the turbine building.
Published: October 15th, 2012 at 3:07 pm ET
- “Very Unexpected”: Large debris filmed in Fukushima Unit 1 shows something explosive happened inside containment (VIDEO) September 27, 2012
- Tepco finds 920 millisieverts per hour in Fukushima Unit 1 torus room — Gundersen: “There are fuel fragments outside the containment” February 20, 2013
- Explosion may have occurred inside vessel of Fukushima Unit 1 — Can generate missiles that endanger containment integrity October 16, 2012
- Kyodo: Water at Fukushima Unit 1 is more radioactive OUTSIDE containment vessel than inside October 12, 2012
- Asahi: Explosive hydrogen may be coming from melted fuel rods and “accumulating near the top of the containment vessel without being driven out” September 25, 2011