What is Mcnp: Definition and 187 Discussions

Monte Carlo N-Particle Transport (MCNP) is a general-purpose, continuous-energy, generalized-geometry, time-dependent, Monte Carlo radiation transport code designed to track many particle types over broad ranges of energies and is developed by Los Alamos National Laboratory. Specific areas of application include, but are not limited to, radiation protection and dosimetry, radiation shielding, radiography, medical physics, nuclear criticality safety, detector design and analysis, nuclear oil well logging, accelerator target design, fission and fusion reactor design, decontamination and decommissioning. The code treats an arbitrary three-dimensional configuration of materials in geometric cells bounded by first- and second-degree surfaces and fourth-degree elliptical tori.
Point-wise cross section data are typically used, although group-wise data also are available. For neutrons, all reactions given in a particular cross-section evaluation (such as ENDF/B-VI) are accounted for. Thermal neutrons are described by both the free gas and S(α,β) models. For photons, the code accounts for incoherent and coherent scattering, the possibility of fluorescent emission after photoelectric absorption, absorption in pair production with local emission of annihilation radiation, and bremsstrahlung. A continuous-slowing-down model is used for electron transport that includes positrons, k x-rays, and bremsstrahlung but does not include external or self-induced fields.
Important standard features that make MCNP very versatile and easy to use include a powerful general source, criticality source, and surface source; both geometry and output tally plotters; a rich collection of variance reduction techniques; a flexible tally structure; and an extensive collection of cross-section data.
MCNP contains numerous flexible tallies: surface current & flux, volume flux (track length), point or ring detectors, particle heating, fission heating, pulse height tally for energy or charge deposition, mesh tallies, and radiography tallies.
The key value MCNP provides is a predictive capability that can replace expensive or impossible-to-perform experiments. It is often used to design large-scale measurements providing a significant time and cost savings to the community. LANL's latest version of the MCNP code, version 6.2, represents one piece of a set of synergistic capabilities each developed at LANL; it includes evaluated nuclear data (ENDF) and the data processing code, NJOY. The international user community’s high confidence in MCNP’s predictive capabilities are based on its performance with verification and validation test suites, comparisons to its predecessor codes, automated testing, underlying high quality nuclear and atomic databases and significant testing by its users.

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  1. E

    MCNP: How to specify a small source in a large lattice

    I am working on an input file in MCNPX/6 that uses a CT scan lattice geometry. I want to specify a small source in a large universe (lung). Right now I have a source uniformly distributed through the universe. The existing documentation is vague on this topic. Is it possible to contain the...
  2. AlbeFerS

    Finding UO2 Enrichment Value for MCNP5 Input File

    Hi there, I´m just finishing an input file for MCNP5 and I can´t find a value of density for UO2 enriched to 3,25% - 3,6%. Does anyone know it or know where I can find it? Thanks in advance! (P.D.: wikipedia is not my friend... )
  3. D

    MCNP-An equivalent way to describe a particular gama source

    I had some problems finding out an equivalent way to describe a particular gama source.We can get the original way describing the particular gama source in this file: "1.txt", as well as its model in this file:"model.jpg",with this describing way,we can get the distribution of gama flux like...
  4. S

    How to Resolve MCNP Depletion Code Syntax Errors?

    Hello, I am a graduate student attempting to run evaluate the depletion of a ceramic film attached to the moderator-side of the fuel clad. I am having some issues with my MCNP syntax/code and I was wondering if one could assist. My input file is attached. I am not looking for someone to...
  5. S

    Mcnp source subroutine linking trouble

    Hi, I have written a source subroutine and I am trying to link it with mcnp6. When I run my input file it says you need a source subroutine. My input file and the source subroutine(written in fortran) are in the same directory. Where do I have to keep the subroutine to link with mcnp? Any help...
  6. zaidtaher

    MCNP Avg. Flux and Assembly Flux

    I want to know the best tally for MCNP Flux (avg and for each assembly) Please help
  7. D

    MCNP planar source (rectangular)

    Hello to everybody, I need some explanation on how to use SDEF variables to define correctly a planar rectangular source. Let say this source is emitting in all direction but I am interested in a side of the source surface where a point detector is located. I used in my example VEC (VEC =001)...
  8. G

    How to use MCNP to calculate power distribution for a reactor core?

    Assume no boron and all control rods out, so the core is super-critical. if KCODE mode is used, and F4 card is for tally the neutron for each assamblies. Can the results represent the power distribution of the core, whether the multiply-factor can affect. the results i get (power...
  9. zaidtaher

    Solve MCNP Input File for AP1000: Get Help Now

    Hello Every body, I hope all is well. I have a problem with MCNP code for 1/8 AP1000, so please can anybody help me ? Regrads
  10. G

    Mcnp error the new source has overrun the old source

    mcnp error "the new source has overrun the old source" I am a beginner with MCNP. This error really confused me. Who knows what this error means? Thank you.
  11. F

    MCNP error about dose claculation of phantom

    Hello,everyone.Lastly,I use MCNP to claculate the dose distribution of CT phantom,but when I run my code,I get a message that says ' bad trouble in subroutine newcel of mcrun source particle no. 18859 starting random...
  12. D

    Why am I getting a fatal error in MCNP with xsdir missing cross-section tables?

    fatal error. *** cross-section tables are missing from xsdir 10001.70m 10002.70m 10003.70m ... bad trouble in subroutine ixsdir of imcn cannot continue with missing cross-section table(s). is the message I am getting. I have created a link using ln -s...
  13. M

    What Are the Different Methods to Define a Plate in MCNP Code?

    I have a question about diffrence between ways of defining a certain plate like (3^1/2)x+y+17.3=0 to MCNP code .for example I know we can define it to MCNP with 15 p 3 2 0 6 but I couldn't understand this method 15 10 0 5 8.66 0 10 0 1
  14. M

    Tips for Learning MCNP: From Basics to Expert

    How to learn MCNP basically?
  15. D

    How Can MCNP Be Used in Industrial Radiography of Steel?

    Hi everyone, I’m a student and in my master degree, I’m working in a project about a bunker for industrial radiography of steel, and I need find some input of mcnp about this matter. Somebody can help me? Thanks a lot
  16. M

    How can you use MCNP to do time-dependent reactor calculations?

    The only thing I know how on the basis of nuclear reactor design is how to run kcode in MCNP and see if my theoretical reactor is critical. How would I be able to calculate how the fuel is burning in my reactor over some period of time, and change my core composition accordingly?
  17. S

    What Does Imp:n=0 Mean in MCNP and How Does it Affect Tally Results?

    hello, I am new to MCNP, could somebody tell me how to use imp:n, what is imp:n=0 means, if neutron importance is 0 in one cell, why the F4 tally is 0 in this cell? how about imp:n=1 or some large number? Thanks for all.
  18. N

    I am a beginner user of MCNP and is still learning how to use it. When

    I am a beginner user of MCNP and is still learning how to use it. When I run my program, I get a message that says 'bad trouble in subroutine main of mcnp'. What exactly does that mean and how can i correct it. Thanks.
  19. M

    Best Linux OS to install/run MCNP with MPI or MPICH

    I've been having difficulty in successfully compiling the MCNP executable with the MPI/MPICH libraries on Scientific Linux 6.x (whatever the latest version is). I'm currently using MCNP5, and the latest distribution DVD. The compiler is GCC, and the MPI is MPICH 1.4.x (the version immediately...
  20. N

    MCNP Input of Voxel Arrays and Their Universes

    Hi I have problems in mcnp input of voxels. I define a voxel arrays and their universes,for example universe1 is defined as: 2001 43 -1.030 -70 u=1 vol=6.795352 but in runing I have below error: fatal error.the surface type is not recognized: -1.03 While 1.03 is the density of...
  21. A

    Is there a free version of MCNP visual editor or similar?

    I have just started to use MCNP code for nuclear reactor modelling. I would like to practice using a visual editor for input file. Can anyone tell me how can I get a free version of visual editor or other similar editor compatible with MCNP?
  22. T

    Comparing Results of MCNP vs Geant4 for Shielding Design

    I'm curious if anyone has any opinions in the results from MCNP vs Geant4 for shielding design. I like that Geant4 uses a more modern syntax, but iv'e also heard that MCNP gives better results.
  23. Q

    MCNP - Measuring Neutron Absorption in a Moderator

    Hello all. I'm am a first time poster but a long time visitor. I am having a little trouble that I was hoping someone far wiser and more knowledgeable than myself might be able to help with. I've been using MCNP to investigate criticality in a simple geometry consisting of a central natural...
  24. C

    Calculating Group Constants for FA with MCNP

    hi there I wnat to calculate the group constants for a FA(fuel assembly) using MCNP (similar to lattice calculations). How can I do it? Please lead me. Thanks alot!
  25. K

    Nuclear Engineering Student Seeking Help with DANTSYS & MCNP

    Hello all, I'm a senior Nuclear Engineering student. This semester I've been working with DANTSYS and MCNP (more like failing to learn properly). I was wondering if anyone had some experience with either program and would be willing to allow me to ask them the occasional question. I think...
  26. S

    Obtaining Temperature-Dependent MCNP Cross Sections Without NJOY

    hello, i am using mcnp for a reactor kinetic study.the only problem is, to establish the model i need to calculate the temperature coefficients, and in order to do that i need to calculate k in different temperatures and therefor need a mcnp library that contains cross-sections for a multitude...
  27. N

    MCNP: SRCTP file with KCODE card

    Hey, I'm modeling the criticality of a core for a university project using MCNP4C. I've run the core on the appropriate KCODE parameters, specifying the source using the KSRC card, and I was looking to cut down on the computing time using the SRCTP files. My problem is that I can't find...
  28. C

    How to Calculate C Parameter in FMn Card for MCNP Code

    Hi there I have a question about FMn card in mcnp code. there is a parameter (is named C) in front of FMn card, I can not understand to calculate the value of that parameter. please help me. thanks alot.
  29. C

    Can MCNPX Perform Time Dependent Calculations?

    Hi there any body know that mcnpx has abality to do time dependent calculations? please lead me quickly, I need it. regards
  30. C

    Temperature in MCNP - Using Library ENDF7 for Research Reactor

    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...
  31. K

    MCNP output file interpretation

    I am running (a very basic) simulation of the proposed LIFE concept reactor at LLNL as part of my MSc thesis. What I hope to achieve is to calculate the fission energy gain from a fissile blanket surrounding a source of fusion neutrons (ie D-T pellet blasted by lasers) The problem summary...
  32. S

    Is MCNP free for Pcs with windows xp?How i can get it?

    Is MCNP free for Pcs with windows xp? How i can get it? regards
  33. A

    How Do I Interpret MCNP Output Table 140 for Reaction Rates?

    Im having some trouble interpreting the MCNP output file, more specificaly table 140 that describes reaction rates. The problem of course is that the acctual reaction rates isn't written but rather things like total colissions, collions*weight, weight lost to capture etc. How do I convert...
  34. B

    Benchmark of high temperature cross section libraries in MCNP

    I need to use this libraries with confidence. Any articles that involves benchmarking of these cross sections?
  35. T

    Create Accurate MCNP Phantom Templates for Radiation Dose Calculations

    Does anyone know if there are templates for things such as the ICRP 23 reference man (70kg)? I am trying to create one for a little side project I am doing (calculating the photon dose my friend gets from sleeping next to his cat that has been treated with I-131). I am trying to create the...
  36. T

    MCNP 5 User Guide: Detailed Documentation & Authorization Info

    I have to write some input for MCNP for one of my classes. The graduate student had given us a lecture and some examples, but I'm trying to find some more detailed documentation, but even anything basic would be nice. The one I did run across, from LANL, I needed authorization to view, why is...
  37. Astronuc

    Understanding Radiation and Radiological Health: A Comprehensive Guide

    " 'New Mexico State University Radiation Safety Manual', is a program prepared by Katrina D. Doolittle with assistance from Trina F. Witter in partial fulfillment of the requirements for a Broad Scope Type AB Radioactive Materials License issued to New Mexico State University. This document...
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