Horace Heffner <hheff...@mtaonline.net> wrote:

> Let's see ...  The total length of that section looks to be about 10 cm.
>>
>> Let's apply your "resistor" calculation.
>>
>> As a first approximation, consider only the shortest path from the
>> thermistor to the fluid.
>>
>> Vin = 100 (Voltage :: Temperature) Steam
>> Vout = 30 : Output of heat exchanger.
>>
>> The "resistance" is proportional to the length of brass between the
>> thermistor and the heat source.
>>
>> For the steam output .. the closest it gets to the thermistor is about 5
>> cm (half the total length)
>> For the heat exchanger it's the thickness of the tube .. say 0.2 cm
>>
>
> On this we may disagree significantly. Take a look at the photos kindly
> provided by Enzo:
>
> http://www.redmatica.com/**media/Thermo1.jpg<http://www.redmatica.com/media/Thermo1.jpg>
> http://www.redmatica.com/**media/Thermo2.jpg<http://www.redmatica.com/media/Thermo2.jpg>
>
> The central brass fitting is very thick. Given the hose ID is about 1.5 cm
> I would guess over a cm thick. It appears the thermocouple was placed not
> far from it.
>
> The intermediate section looks to be at least 0.75 cm thick
>
> From the location of the tape, and the protruding thermocouple, in: . . .
>

Okay TIME OUT. Stop worrying about this. Forget about the damned
thermocouples altogether. Pretend they were not there. Stop obsessing over
small technical details and Look At The Facts:

When the power went off, the reactor was boiling inside and the surface was
around 80 deg C.

Nearly 4 hours later, the reactor was still boiling inside. The surface was
still 80 deg C. Whether the thermocouples were properly placed or in the
wrong places altogether, all of them still showed elevated temperatures.
This was after 2.4 tons of cooling water went through the heat exchanger.

Deal with that! Explain it. You know perfectly well that if no heat had been
generated inside, every temperature sensor would have equaled ambient air or
the tap water temperature soon after the power was turned off.  You can see
that from the decay curve after the power finally went off. There was a
tremendous flow of water going through. What else could happen?!?

Forget all about the cooling water outlet thermocouple. Or, if you like,
assume that it was placed as badly as it could be, so that it picked up the
steam temperature and the air temperature more than the cooling water.
Question: what temperature would it be 1 hour after the power is turned off?
25 deg C. What would it be 2 hours later? 25 deg C. Four hours later? 25 deg
C. ALL THE OTHER SENSORS WOULD ALSO BE AT 25 deg C. They are not. Lewan
would have put his hand on the reactor and find it is stone cold. He would
hear no boiling. That is not what happened.

Deal with the irrefutable first-principle physical evidence that you have in
abundance, and stop fretting about details you do not have and will not get.

- Jed

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