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    Re: Iodide:
    From: Lu Abel
    Date: 2011 Mar 19, 18:30 -0700
    Alan:

    I totally agree with your recollection of the TMI incident -- poor design of the valve indicating system.

    On to Fukushima:

    First of all, let's note the temperature that a reactor core operates at.  It's over 1500F, if I recollect correctly.  This is because we're not talking about simply boiling water but generating steam at very high pressures to drive a turbine on the generator.

    The Fukushima reactors were all automatically "scrammed" -- shut down -- the minute the earthquake hit.  Within moments thereafter, the Fukushima plant went "off-grid" and lost any electrical feed from the outside world.

    An emergency shutdown and loss of outside electrical power was well anticipated in the design of the reactors.   Each and every one of them have massive diesel-powered water pumps connected to outside cooling towers to circulate more than sufficient water into the reactor core to cool it down. 

    Those pumps, were, however, located in the ground floor of the reactor buildings.   But when 10 ft tidal wave from the tsunami hit them and they were disabled if not torn completely away.  In fact, one video showed an entire building that was being carried by the tidal wave being smashed against the emergency pump building.

    So in a very strong sense, the question around the Fukushima disaster is whether it would have been reasonable in their design to have anticipated this sort of natural disaster.   The reactors appear to have survived one of the strongest earthquakes ever recorded -- but they didn't survive the tsunami.

    Lu



    From: Alan <alan202---.net>
    To: NavList@fer3.com
    Sent: Sat, March 19, 2011 4:45:18 PM
    Subject: [NavList] Re: Iodide:

    Lu:

    The following excerpted from your post, "The core remains hot, though, and in both cases auxiliary cooling systems designed to cool the core failed."

    It would appear that, putting it politely, insufficient attention was given to the necessity, the importance of maintaining the availability, the flow of cooling water.

    Re TMI, from what I’ve read about it, the following seemed to have been a major contributor to problems there. Instrument failure, as follows. It seems that the situation, particular valving being open or closed, was not indicated, as it should have been, which reflected the below mentioned poor instrument design.

    The valve in question was solenoid operated. Instrument panel indicators showed the position of the solenoid, which in theory would have indicated the situation with the valve, open or closed. Unfortunately, the "push rod" or "pull rod", whichever it was, which actually operated the valve had been disconnected from the valve itself, so that while the solenoid was "pushing" or "pulling", due to it's being disconnected from the valve, nothing happened, though instrument/control panel indicators said otherwise, ergo bad instrument design. Limit switches attached to or mounted on the valve itself would have shown the position of the valve itself.

    The foregoing represents my understanding of the incident, which could be wrong.

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