MFMP:LFH - LION2 100% Replication well beyond LION1

  • Alan Smith


    I have a question about the operation of the Model T. Am I right in thinking that the only way that the test chamber can go above its set temperature at steady state is by the reactor going into runaway mode? It seems to me that if the reactor is simply giving off excess heat, the PID controller should reduce the input current until the set temperature is regained.


    If I am right in this then judging by the high-temperature effects seen in Bob Greenyer's post-mortems of Lion 1 and LION 2, the control side should have been quite cool -- almost ambient temperature -- during the runs. It should definitely have not been glowing and LION should almost have been able to touch it without protective gloves.

  • Am I right in thinking that the only way that the test chamber can go above its set temperature at steady state is by the reactor going into runaway mode? It seems to me that if the reactor is simply giving off excess heat, the PID controller should reduce the input current until the set temperature is regained.


    You are right. But of course, the temperature will only go down if there is no anomalous heat. What we don't yet know is which port the PID thermocouple was in. Control or test? I don't know. The control side would be far from cool even with no input- with the test port alongside (about 3 cms away) at what appears to be 1200C plus thermal leakage between ports would probably push the control port temperature to 500- 600C or so. LION told me that 'huge waves of heat' were being given off, and that kind of heat laughs at a little insulating brick.

  • Hi Bruce. A worthy suggestion but I'm not sure that a Model T could get the copper hot fast enough to melt it before it oxidises. Wrong kind of furnace, wrong kind of copper. Thin wire (0.6mm) has a high surface area to volume ratio which makes rapid oxidation in the 800C+ zone fairly fast., and the furnace environment is also oxidative rather than reductive as a smelter would be. By putting a ceramic wool blanket on top of the reactor I know I can get to 1150C which is 100C more than the melting point of copper, but 300C or so under the melting point of copper oxide. If I up the voltage to increase the heat still more, I run every chance of frying the heater coils.


    Interesting experience-based observations. Thanks!

  • You are right. But of course, the temperature will only go down if there is no anomalous heat.


    I've gotten myself a bit confused here. Do you mean that the temperature on the control side will only go down if there is no anomalous heat? I don't understand that.


    Here is my picture of all this. Suppose that the PID thermocouple is on the active reactor side and the reactor is generating anomalous heat. In that case the active side temperature will begin to rise but the PID controller will see this and reduce the input current so as to keep the temperature on the active side stable. Under these conditions the temperature of the control side will be whatever is generated by the input current plus whatever heat is flowing into it from the active side. If the anomalous heat generated by the active reactor increases the PID will accordingly lower the input current even more and this will cause the control side temperature to cool off even more. The only way that the steady-state active side temperature can rise above the set point is when the input current is zero because at that point PID control has hit a floor and is useless. At this point the control side will be heated exclusively by the heat leaking over from the active side. So the mark of anomalous heat generation whould be a decline in control side temperate until the active side goes into runaway mode and then the sky is the limit.

  • I mean that the system temperature would only go down with the PID switched out if there was no anomalous heat coming from elsewhere. Since we do not know for sure how LION arranged his thermocouples and which port was switching the system on and off there is little point in speculation. I am hunting data right now.

  • I mean that the system temperature would only go down with the PID switched out if there was no anomalous heat coming from elsewhere. Since we do not know for sure how LION arranged his thermocouples and which port was switching the system on and off there is little point in speculation. I am hunting data right now.


    Good explanations. Thanks.


    I didn't realize that so little is known of LION's procedures. I thought it was only the temperature that we don't know.

  • I didn't realize that so little is known of LION's procedures


    I spent 6 hours face to face discussing protocols with LION recently. I am happy we know enough to be confident about performing a replication using the same or very similar procedures. Data gathering techniques however are my own, and if successful will be rigorous, and there will be many more replications before the summer is done. There is no way this one is getting away.

  • I spent 6 hours face to face discussing protocols with LION recently. I am happy we know enough to be confident about performing a replication using the same or very similar procedures. Data gathering techniques however are my own, and if successful will be rigorous, and there will be many more replications before the summer is done. There is no way this one is getting away.


    That is good news! Thanks for all your efforts!

  • ....some interesting data (moderately interesting at least) from a 'dummy run' using the LION protocols but with under-prepared diamonds.


    As mentioned above- most interesting thing here is the rising trend in radiation count (Netto Geiger with SBM-20 detector tube) which was positioned 60 mm away from the 'hot tube'. Thermo 1 is the control port, Thermo 0 is the diamond dummy port.

         

  • As mentioned above- most interesting thing here is the rising trend in radiation count (Netto Geiger with SBM-20 detector tube) which was positioned 60 mm away from the 'hot tube'. Thermo 1 is the control port, Thermo 0 is the diamond dummy port.

         


    It's even better to use HPGE, a BGO scintillation detector or a cloud chamber to analyze these unknown low-energy or even high-energy radiation.

  • I'm not expert, but if electronic device detect radiation, a good cross check could be to use a non electronic detector, like x-ray dental film, or maybe cheaper argentic High ISO/ASA film. I imagine this have been done (JP Biberian used dental film, as many others... never heard of photographic Ag film, so maybe is it stupid).

    Another more recent idea could be to use a CMOS or CCD photodetector... ie a good digital camera.

    If not evidence it can gives hints, since it will produce an image.

  • AlainCo


    I have X-ray film coming. Not used here, since nothing much was expected to happen. It will be deployed later.


    can


    Inside the fuel tube the atmosphere consists of some ambient air and D20 vapour. When the temperature rises, so does pressure with the formation of superheated D2O steam. At 800C we can only estimate the pressure, but it could be as high at 90Bar, or as low as 10Bar. Quite a lot, either way.

  • As mentioned above- most interesting thing here is the rising trend in radiation count (Netto Geiger with SBM-20 detector tube) which was positioned 60 mm away from the 'hot tube'. Thermo 1 is the control port, Thermo 0 is the diamond dummy port.

         


    Because the counter tube was quite close (60mm) from the hot tube can it be that the counter tube was heated (by IR radiation eg) to some degree as well and that is the reason for the rising trend in ur radiation count?

  • An easy way to see if the temperature of the detector tube and the radiation count are correlated would be to attach a cheap thermocouple to the SBM-20.

    If you still have one to spare.

    I was trying to find some information about the temperature dependency of the SBM-20 online but since its russian origin and I cant read cyrillic it's a bit hard ;)


    edit: I didnt find anything about the temperature dependence of the SBM-20 yet but somebody made a quite comprehensive characterization of it.

    Maybe it comes in handy for you.

    http://uvicrec.blogspot.de/201…0-geiger-muller-tube.html

  • As mentioned above- most interesting thing here is the rising trend in radiation count (Netto Geiger with SBM-20 detector tube) which was positioned 60 mm away from the 'hot tube'. Thermo 1 is the control port, Thermo 0 is the diamond dummy port.

         


    There is an early region of temperature stability roughly between time points 1500 and 4700. I note that the end of this period of temperature stability coincides with a stepwise increase in the radiation count.


    If the reason for the temperature behaviour is known then perhaps this also explains the change in rad count.

  • There is an early region of temperature stability roughly between time points 1500 and 4700.


    I think that coincided with me having lunch and not being there to tweak up the reactor temperature.


    An easy way to see if the temperature of the detector tube and the radiation count are correlated would be to attach a cheap thermocouple to the SBM-20.

    If you still have one to spare.


    That would have to be done in the context of a control experiment of course. And all previous control experiments have given me a flat line - no trend up or down. But under the current regime, I thank you for your suggestion and will see what happens when you toast the tube a little.