Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Temperature in MCNP

  1. Dec 31, 2009 #1
    Hi there,
    I want to know that how can involve the temperature in mcnp code.
    for example; the library endf7 for mcnp has five certain temperature:300 kelvin, 600 kelvin, 900 kelvin, 1200 kelvin & 1500 kelvin. if I want to calculate flux distribution in 330 kelvin for a research reactor, how can I?

    best regards
  2. jcsd
  3. Jan 1, 2010 #2


    User Avatar
    Staff Emeritus
    Science Advisor

    Is there no temperature dependence functions.

    One could interpolate, or given than 330 K is ~ 300 K, simply use 300 K. The Doppler broadening shouldn't be too significant going from 300 K to 330 K. The density changes are not very significant either.
  4. Jan 1, 2010 #3
    Hi Astronuc.
    I have another question; TMP card in MCNP that can be entered at cell card have not any effect in result of calculations?
    Please, more explain about that, I need.

    have best time.
  5. Jan 12, 2010 #4
    TMP card is used for the energy of thermal neutrons so you have have to accomodate the material temperatures
  6. Jan 13, 2010 #5

    for temperature, there is a nuclear code to produce the library for it...
    an NJOY, but it some kind of rare code...

    by MODUL ACER, you can create the applicable data for any temperature...and it is also applicable for WIMS...

    but, I do agree with Mr. Astronuc...
  7. Feb 15, 2011 #6
    If the value of TMP parameter (or its default value if not given explicitly) in a cell card differs from temperature of nuclide in cross-section file, then MCNP modifies the nuclide cross-section using free-gas treatment (you can see a warning message during execution and in output file). It resets temperature to the room temp. and then (if a TMP value given) to the requested temperature. I haven't dug into this problem, but from what I heard, the free-gas treatment is not very precise procedure. The treatment happens even if you have difference in the last digit, i.e. negligible. This can potentially produce unnecessary discrepancy in your results. Please, correct me if it is wrong.

    Last edited by a moderator: Feb 17, 2011
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook