Study? No temperature readings for concrete floor — Outcome based on Tepco “projections” of decay heat & uses computer model from Westinghouse

Published: November 30th, 2011 at 7:42 pm ET


Containment vessels held: simulation test, Japan Times, Dec. 1, 2011:

The primary containment vessels of reactors 1, 2 and 3 at the Fukushima No. 1 power plant probably managed to contain the melted nuclear fuel, according to the findings of a Tokyo Electric Power Co. computer simulation released Wednesday. […]

“the melted fuel remained inside the containment vessels,” Tepco said in a report on the simulation’s findings […]

Simulation based on projections by Tepco, using program from nuclear industry giant Westinghouse

Tepco said the calculations were based on the pessimistic [???] assumption that 100 percent of the fuel in reactor 1 melted through the pressure vessel and into the primary containment vessel, and that 57 percent of the nuclear fuel in reactor 2 and 63 percent of the fuel in reactor 3 penetrated through to the containment vessels.The simulation also was based on projections Tepco made, including its calculations of the decay heat released by the melted nuclear fuel. The utility used the Modular Accident Analysis Program developed by Fauske & Associates LLC, a subsidiary of U.S.-based Westinghouse Electric and a pioneer in computer models that analyze severe accidents at nuclear power plants.

Temperature Readings

The temperatures in the containment vessels and at the bottom of the pressure vessels have been stable and recently measured less than 100 degrees as of Wednesday.

The temperatures in the containment vessels’ concrete floors, however, are not known.

Published: November 30th, 2011 at 7:42 pm ET


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  2. AP: New gov’t study rasies possibility of “structural damage to reactor’s foundation” — Erosion of concrete could be deeper than Tepco claims December 1, 2011
  3. Report: If fuel melted through reactor, it would react with concrete floor of primary containment — Could add significantly to total radiation release May 23, 2011
  4. NHK: “This is a very severe accident” — Nuclear fuel at Reactor No. 1 may have melted through 65 cm of concrete… Only 37 cm at thinnest point (PHOTOS) November 30, 2011
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7 comments to Study? No temperature readings for concrete floor — Outcome based on Tepco “projections” of decay heat & uses computer model from Westinghouse

  • Japan has the fastest computers in the world, hook one of then up to all the data and see what it says !

  • arclight arclight

    some info about the corium from chernobyl here…

    “From analysis of the lava’s composition, Pazukhin estimated that the maximum temperature of the explosion was about 2255 degrees Celsius and that the lavas must have been held at a temperature greater than 1660 degrees for at least 4 days. He believes that when the reactor exploded, chunks of concrete from the walls collapsed into the reactor chamber. The fuel rods heated to the point that their zirconium cladding melted, exposing the uranium oxide fuel. About 4 hours later, melting concrete, zirconium, and uranium oxide began to mix with about 145 tons of the mineral serpentine which was packed around the reactor as heat insulation. Within half an hour the serpentine heated to more than 500 degrees Celsius and began to decompose, releasing 19 tons of superheated water as vapor. The melted materials cooked for another 60 hours, forming a lava that flowed into several damaged rooms beneath the reactor chamber.”

    no sign of decommissioning chernobyl any time soon…. what hope the daichi??

    • Bobby1

      The concrete reaction is what makes the strontium, barium and cerium bubble up and out of the mix, and the concrete dust helps it go high into the atmosphere and travel long distances.

      The pressure vessel blowing up, by itself, is much less significant than having a bubbling corium-concrete mix.

  • Hemisfear311 Hemisfear311

    I doubt if there was ever any device added to the concrete floor to measure the temperature or anything else.

    Perhaps the nuke industry is installing such devices now in existing plants around the world along with cameras and geiger counters so they can monitor the future disasters that are bound to happen.

  • jec jec

    Key to this post..its SIMULATION..its a guide, but NOT FACT. Fact is they just do not know..and to make assumptions without data..which TEPCO continues to very misleading. Just observations of the fallout over Japan, the massive amounts and “hot spots” , contamination in the ocean..means this is a SEVERE accident. TEPCO must consider the worst case–its out of the containment,into concrete..and SINKING towards the water table. Not sure exactly what might occur then, but contamination of greater areas is a given. Again, all the comments on “status”–its a computer simulation..its NOT REAL WORLD. Its a “best guess” about an event that no one has any experience with at this level of disaster….

  • Well if the fuel is A ok.

    I suppose tepco can just send someone in there to double check right 😉
    Send Kan.

    He seemed like he was sure that the crisis was in good hands!