Recent content by matthewdb

  1. M

    Japan Earthquake: Nuclear Plants at Fukushima Daiichi

    I didn't think they had malfunctioning sensors at TMI, just a failure to understand their meaning. They didn't consult a steam table to realize that the pressure and temperature they had were for steam not sub-cooled water. Because of this all PWM plants in the US now have a subcooling...
  2. M

    Japan Earthquake: Nuclear Plants at Fukushima Daiichi

    Hydrogen is phenomenally easy to ignite. With most fuels it is effective to control ignition sources to prevent explosions. With hydrogen it is irrelevant. You must prevent explosive mixtures from forming because minute static discharges from airflow can ignite it.
  3. M

    Firefox Not Working with PF: Error 404

    I am going to the main page: https://www.physicsforums.com/ It will work for a while if I clear the cache and then it will quit on my next visit. I've just started using private mode and then it works fine. Private mode doesn't allow websites you are browsing to see your cookies so I'm sure...
  4. M

    Effect of Solar Storms on the Grid and Nuke Plants?

    The CANDU design can stay in operation after a grid disconnect. They stay at high power at first to avoid problems with Xenon instability. The generator is only making enough power to meet the needs of the auxiliaries and the rest of the thermal energy is dumped into the condenser by steam...
  5. M

    Firefox Not Working with PF: Error 404

    OK, what did I do to make it quit? It wasn't a bad URL since I'm using a bookmark in both cases under FF and by purging the cache it works.
  6. M

    Firefox Not Working with PF: Error 404

    That did it, thanks. What is weird is that it stopped working today on both my home and work computers. Different ISP, FF version and OS...
  7. M

    Japan Earthquake: Nuclear Plants at Fukushima Daiichi

    No. The pipe routing in a BWR and a PWR are quite similar. The pipes are big and expensive and the owner of the plant doesn't want to buy more than they have to. They are around 3/4 m in diameter and there are 4 in parallel. 70 seconds of pipe would be an incredible maze. The biggest...
  8. M

    Firefox Not Working with PF: Error 404

    Anyone else having a problem with PF in firefox? It works fine in IE (but I hate IE...) When I try it in firefox I get this message: Method Not Implemented GET to /showthread.php not supported. Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument...
  9. M

    Japan Earthquake: Nuclear Plants at Fukushima Daiichi

    I think we have multiple uses of the word "airlock" meaning quite different things. At the entrance to the reactor building there are double doors forming an airlock that prevents disruption of the normal airflow pattern to prevent undesired contamination movement. These are your typical...
  10. M

    Japan Earthquake: Nuclear Plants at Fukushima Daiichi

    I was incorrect at stating it is N-17, thanks rmattila. The N-16 is the majority of the immediate dose since the high energy gamma penetrates the piping. N-17 is a concern over time because it slowly activates the metal of the piping and turbines. The N-16 is extracted at the condenser...
  11. M

    Japan Earthquake: Nuclear Plants at Fukushima Daiichi

    Not necessarily a tightly closing door - they are just high quality ordinary security doors. Plants rely on positive airflow from the ventilation systems. Airflow is arraigned to flow first to areas people will occupy and then is ventilated out from the areas of highest contamination. All...
  12. M

    Japan Earthquake: Nuclear Plants at Fukushima Daiichi

    No, not even close. The airlock is for going into primary containment. The secondary containment and the turbine building are ventilated to the outdoors. The turbine is not normally approached under power due to gamma from N-17. It has a bioshield around the turbine and main steam lines...
  13. M

    Japan Earthquake: Nuclear Plants at Fukushima Daiichi

    The IC is under reactor pressure all the time. If the exchanger or any associated piping were to spring a leak the only thing to stop the flow of reactor steam would be the isolation valves. The inside set of valves is only closed in case of a leak. There is a mass balance calculator that...
  14. M

    Japan Earthquake: Nuclear Plants at Fukushima Daiichi

    Thank you tsutsuji You middle diagram could explain why the IC wasn't able to operate after the tsunami. It states that the IC received a isolation signal so the AC valves inside containment were commanded to close. Since they are inside containment they are impossible to open...
  15. M

    Japan Earthquake: Nuclear Plants at Fukushima Daiichi

    There are two valves in the return line. There is one outside containment is DC operated and normally closed. There is one inside containment that is AC operated and normally open. The inside one is only closed if there is very high flow indicating a ruptured pipe. The valve outside...
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