# Validation and Verification **URL:** https://openmc.discourse.group/c/validation-and-verification/8.md?page=1 [Latest](https://openmc.discourse.group/latest.md) · [Categories](https://openmc.discourse.group/categories.md) **Page:** 2 --- ## [Difference in multiplication factor](https://openmc.discourse.group/t/difference-in-multiplication-factor/2701)
**Author:** [@Denis\_Solovyev](https://openmc.discourse.group/u/Denis_Solovyev)\ **Replies:** 1\ **Last updated:** [May 9, 2025, 2:47pm UTC](https://openmc.discourse.group/t/difference-in-multiplication-factor/2701 "2025-05-09T14:47:40Z")
Hello. We are preparing two group neutron cross sections for VVER fuel assembly. Then we compare k\_inf computed by OpenMC and k\_inf\_xs calculated using the prepared by OpenMC two group neutron cross sections as follow… --- ## [Geometry of fuel log TMSR-500 ThorCon International design](https://openmc.discourse.group/t/geometry-of-fuel-log-tmsr-500-thorcon-international-design/5477)
**Author:** [@Nopra\_algusduri](https://openmc.discourse.group/u/Nopra_algusduri)\ **Replies:** 0\ **Last updated:** [May 2, 2025, 2:20pm UTC](https://openmc.discourse.group/t/geometry-of-fuel-log-tmsr-500-thorcon-international-design/5477 "2025-05-02T14:20:40Z")
I am currently conducting a geometric validation study to replicate the fuel log configuration of the TMSR-500 reactor, as proposed by ThorCon Indonesia. This structure consists of vertical fuel slabs embedded within a h… --- ## [Converting OpenMC Flux Unit to Match MCNP](https://openmc.discourse.group/t/converting-openmc-flux-unit-to-match-mcnp/5265)
**Author:** [@Ghotme](https://openmc.discourse.group/u/Ghotme)\ **Replies:** 3\ **Last updated:** [March 16, 2025, 9:31am UTC](https://openmc.discourse.group/t/converting-openmc-flux-unit-to-match-mcnp/5265 "2025-03-16T09:31:25Z")
Hello Everyone, In OpenMC, the flux unit is particles/(cm² · source particle), whereas in MCNP, it is particles/cm²/s. To match the unit in OpenMC to that of MCNP, can we multiply the OpenMC flux by the source strength … --- ## [Multiple transfer rate](https://openmc.discourse.group/t/multiple-transfer-rate/5284)
**Author:** [@M\_Alridz](https://openmc.discourse.group/u/M_Alridz)\ **Replies:** 0\ **Last updated:** [March 3, 2025, 5:49am UTC](https://openmc.discourse.group/t/multiple-transfer-rate/5284 "2025-03-03T05:49:48Z")
Im kinda new to OpenMC, and currently im currently doing small research on MSR reactor where there is continuous fuel processing. In OpenMC there is trasnfer rate feature, so i can get rid all the burnable poison like Xe… --- ## [Trying to model SD-TMSR using OpenMC](https://openmc.discourse.group/t/trying-to-model-sd-tmsr-using-openmc/5029)
**Author:** [@daffwz](https://openmc.discourse.group/u/daffwz)\ **Replies:** 3\ **Last updated:** [December 7, 2024, 4:00pm UTC](https://openmc.discourse.group/t/trying-to-model-sd-tmsr-using-openmc/5029 "2024-12-07T16:00:52Z")
I am new to OpenMC and i am trying to recreate an SD-TMSR model based on this paper here (A neutronic evaluation of a thorium-based molten salt breeder reactor - ScienceDirect). All the fuel composition, temp., density,… --- ## [ERROR get\_atoms from depletion result](https://openmc.discourse.group/t/error-get-atoms-from-depletion-result/4987)
**Author:** [@MAKurniwawan](https://openmc.discourse.group/u/MAKurniwawan)\ **Replies:** 1\ **Last updated:** [December 4, 2024, 10:47pm UTC](https://openmc.discourse.group/t/error-get-atoms-from-depletion-result/4987 "2024-12-04T22:47:48Z")
Hi, everyone, I get an error when trying to get get atom. Can someone tell me what part I’m having problems with? \`import numpy as np import matplotlib.pyplot as plt import openmc.deplete import openmc import pandas… --- ## [Astonishing axial zone divsion effects](https://openmc.discourse.group/t/astonishing-axial-zone-divsion-effects/5022)
**Author:** [@okum](https://openmc.discourse.group/u/okum)\ **Replies:** 2\ **Last updated:** [December 4, 2024, 2:51am UTC](https://openmc.discourse.group/t/astonishing-axial-zone-divsion-effects/5022 "2024-12-04T02:51:40Z")
The reactor core consists of pin-type cylinders with an axial length of 80 cm and is composed of fuel rods, burnable poison rods, and control rods. Using the OpenMC code, the following three types of burnup calculations … --- ## [Zircaloy-4 activation with JEFF33 depletion chain (Nb97\_m1)](https://openmc.discourse.group/t/zircaloy-4-activation-with-jeff33-depletion-chain-nb97-m1/4932)
**Author:** [@KUNG](https://openmc.discourse.group/u/KUNG)\ **Replies:** 2\ **Last updated:** [November 8, 2024, 3:29pm UTC](https://openmc.discourse.group/t/zircaloy-4-activation-with-jeff33-depletion-chain-nb97-m1/4932 "2024-11-08T15:29:45Z")
Hi everybody, I am looking into the activation of the cladding in a PWR pincell and compare the cladding transmutation results from OpenMC with FISPACT-II (using the tallied cladding spectra from OpenMC in FP as an inpu… --- ## [Neutron spectrum of MSRE cad design](https://openmc.discourse.group/t/neutron-spectrum-of-msre-cad-design/4889)
**Author:** [@Rajin000](https://openmc.discourse.group/u/Rajin000)\ **Replies:** 0\ **Last updated:** [October 16, 2024, 8:56pm UTC](https://openmc.discourse.group/t/neutron-spectrum-of-msre-cad-design/4889 "2024-10-16T20:56:32Z")
I have a spectrum in the cad design of a Molten Salt Reactor experiment for the fuel (NaF-KF-UF4) with a 27% enrichment using openmc. There is no leakage in the cad design. Is this acceptable as a thermal reactor spec… --- ## [The difference flux between openMC and MCNP(MCX)](https://openmc.discourse.group/t/the-difference-flux-between-openmc-and-mcnp-mcx/4879)
**Author:** [@tRNA](https://openmc.discourse.group/u/tRNA)\ **Replies:** 2\ **Last updated:** [October 11, 2024, 7:22pm UTC](https://openmc.discourse.group/t/the-difference-flux-between-openmc-and-mcnp-mcx/4879 "2024-10-11T19:22:41Z")
hi,nowadays I try to use openMC to calculate the flux about BSA in BNCT openMC flux=20.3288 MCNP flux=44.667 MCX(a MC program developped by XJTU) flux=45.13 I dont know how to solve it --- ## [Difference in neutron flux between OPENMC and MCNP6](https://openmc.discourse.group/t/difference-in-neutron-flux-between-openmc-and-mcnp6/4824)
**Author:** [@Criss](https://openmc.discourse.group/u/Criss)\ **Replies:** 1\ **Last updated:** [September 24, 2024, 9:25am UTC](https://openmc.discourse.group/t/difference-in-neutron-flux-between-openmc-and-mcnp6/4824 "2024-09-24T09:25:05Z")
Hi everyone, I am encountering a 22% difference in neutron flux calculated between OPENMC and MCNP6 for a simple system with a fixed source. The flux was calculated in the volume of the system. From what I have read on … --- ## [Transmutation results different from FISPACT-II](https://openmc.discourse.group/t/transmutation-results-different-from-fispact-ii/4714)
**Author:** [@tcsousa99](https://openmc.discourse.group/u/tcsousa99)\ **Replies:** 4\ **Last updated:** [August 22, 2024, 11:43am UTC](https://openmc.discourse.group/t/transmutation-results-different-from-fispact-ii/4714 "2024-08-22T11:43:44Z")
Hello all! I’ve been doing transmutation calculation with Rhodium with OpenMC and comparing them with known results from FISPACT-II. I cannot post my code because I’m a new user but I will add as text at the end. Nevert… --- ## [Neutron Inelastic Scattering](https://openmc.discourse.group/t/neutron-inelastic-scattering/4659)
**Author:** [@pferney](https://openmc.discourse.group/u/pferney)\ **Replies:** 2\ **Last updated:** [August 12, 2024, 11:34pm UTC](https://openmc.discourse.group/t/neutron-inelastic-scattering/4659 "2024-08-12T23:34:54Z")
HI everyone, The doc is a little unclear to me : What happen to neutron having inelastic scattering reaction ? Does the code continue the tracking of the neutron out ? Is it considered like a new neutron (new track) or … --- ## [Error while running a Pincell model](https://openmc.discourse.group/t/error-while-running-a-pincell-model/4652)
**Author:** [@AsukuA](https://openmc.discourse.group/u/AsukuA)\ **Replies:** 4\ **Last updated:** [August 7, 2024, 3:03pm UTC](https://openmc.discourse.group/t/error-while-running-a-pincell-model/4652 "2024-08-07T15:03:35Z")
Good morning. I ma new to OpenMC. I am trying to implement an example pincell model but i get the following error. The following is my input. I am using a windows 10 OS import os import openmc Set the OPENMC\_CROSS\_S… --- ## [Continuing to investigate convergence](https://openmc.discourse.group/t/continuing-to-investigate-convergence/4640)
**Author:** [@fhoerold](https://openmc.discourse.group/u/fhoerold)\ **Replies:** 0\ **Last updated:** [July 31, 2024, 9:16pm UTC](https://openmc.discourse.group/t/continuing-to-investigate-convergence/4640 "2024-07-31T21:16:20Z")
Related to my previous question I’d like to dig a little deeper. I’ve taken some time to read the OpenMC documentation in more detail. For my work, I think it could be interesting to inspect the convergence rates of k\_{… --- ## [K-inf natural Uranium infinite geometry keff seems too low](https://openmc.discourse.group/t/k-inf-natural-uranium-infinite-geometry-keff-seems-too-low/4539)
**Author:** [@coupled](https://openmc.discourse.group/u/coupled)\ **Replies:** 1\ **Last updated:** [July 10, 2024, 7:31am UTC](https://openmc.discourse.group/t/k-inf-natural-uranium-infinite-geometry-keff-seems-too-low/4539 "2024-07-10T07:31:16Z")
Thanks for this awesome simulation tool. As a test I filled a reflective cube (all 6 sides reflective) with metallic density natural Uranium (235-U : 0.007172 the rest is 238-U … No 16-O…) and calculated keff for infin… --- ## [Depletion problem with multiplying media in external sources](https://openmc.discourse.group/t/depletion-problem-with-multiplying-media-in-external-sources/4355)
**Author:** [@MIB101](https://openmc.discourse.group/u/MIB101)\ **Replies:** 5\ **Last updated:** [June 11, 2024, 8:36pm UTC](https://openmc.discourse.group/t/depletion-problem-with-multiplying-media-in-external-sources/4355 "2024-06-11T20:36:23Z")
Hi All I’ve been experimenting with the depletion module and doing some benchmarking against FISPACT. I’ve been running into large discrepancies when doing activation calculations of multiplying media in external source… --- ## [Keff converges, but the value depends on the initial seed](https://openmc.discourse.group/t/keff-converges-but-the-value-depends-on-the-initial-seed/4178)
**Author:** [@yurikh](https://openmc.discourse.group/u/yurikh)\ **Replies:** 1\ **Last updated:** [April 21, 2024, 6:45pm UTC](https://openmc.discourse.group/t/keff-converges-but-the-value-depends-on-the-initial-seed/4178 "2024-04-21T18:45:20Z")
I built a model and try to benchmark it with the experimental critical states of the ETRR2 research reactor. This reactor has a small light water moderated and reflected core, with several beryllium reflector elements a… --- ## [Keff indiscrepency when modelling TRISO fuel particles](https://openmc.discourse.group/t/keff-indiscrepency-when-modelling-triso-fuel-particles/3958)
**Author:** [@es2517](https://openmc.discourse.group/u/es2517)\ **Replies:** 1\ **Last updated:** [March 1, 2024, 3:32pm UTC](https://openmc.discourse.group/t/keff-indiscrepency-when-modelling-triso-fuel-particles/3958 "2024-03-01T15:32:15Z")
Hello, I’m modelling TRISO fuel particles in a box (1cmx1cmx1cm). I have taken the example from this post Simulation Triso - #2 by mkreher13. I ran the example first and got kinf ~ 1.06. I have then changed the material… --- ## [Plotting Geometry Problem](https://openmc.discourse.group/t/plotting-geometry-problem/3975)
**Author:** [@hkumi](https://openmc.discourse.group/u/hkumi)\ **Replies:** 2\ **Last updated:** [February 28, 2024, 12:43pm UTC](https://openmc.discourse.group/t/plotting-geometry-problem/3975 "2024-02-28T12:43:32Z")
Hello everyone, I am new openmc. I want to make a simple geometry of a wall filled with rock with thickness 0.5m. I have created the geometry following the examples. I tried to plot the geometry and I just see a 2D imag… --- ## [Error in cross-section](https://openmc.discourse.group/t/error-in-cross-section/3968)
**Author:** [@hkumi](https://openmc.discourse.group/u/hkumi)\ **Replies:** 6\ **Last updated:** [February 27, 2024, 1:35pm UTC](https://openmc.discourse.group/t/error-in-cross-section/3968 "2024-02-27T13:35:35Z")
I have made a simple code to find transmission and back scattered neutrons after interacting with a rock wall stacked together with water wall. I have error processing the cross-section. this is the code. import openmc … --- ## [Problem with U235 concentration with burnup of the PWR fuel cell](https://openmc.discourse.group/t/problem-with-u235-concentration-with-burnup-of-the-pwr-fuel-cell/3668)
**Author:** [@Denis\_Solovyev](https://openmc.discourse.group/u/Denis_Solovyev)\ **Replies:** 2\ **Last updated:** [February 27, 2024, 10:16am UTC](https://openmc.discourse.group/t/problem-with-u235-concentration-with-burnup-of-the-pwr-fuel-cell/3668 "2024-02-27T10:16:38Z")
Hello. We solve the problem of high burnup of a PWR fuel cell (up to 100 MWd/kgHM) with an enrichment of 9.75% in U235. The description of the problem is given in the attached dissertation (Design Strategies for Optimiz… --- ## [Serpent and OpenMC TRISO Discrepency](https://openmc.discourse.group/t/serpent-and-openmc-triso-discrepency/3938)
**Author:** [@am4020](https://openmc.discourse.group/u/am4020)\ **Replies:** 0\ **Last updated:** [February 20, 2024, 2:19pm UTC](https://openmc.discourse.group/t/serpent-and-openmc-triso-discrepency/3938 "2024-02-20T14:19:05Z")
I have tried running a problem of a 2x2 cube filled with TRISO fuel to try to break down a discrepancy I am getting when I try running a TRISO filled pin cell model in OpenMC compared to Serpent. However, even with this … --- ## [Serpent vs Open MC Discrepancy for PinCell (TRISO Fuel)](https://openmc.discourse.group/t/serpent-vs-open-mc-discrepancy-for-pincell-triso-fuel/3937)
**Author:** [@am4020](https://openmc.discourse.group/u/am4020)\ **Replies:** 0\ **Last updated:** [February 20, 2024, 1:16pm UTC](https://openmc.discourse.group/t/serpent-vs-open-mc-discrepancy-for-pincell-triso-fuel/3937 "2024-02-20T13:16:56Z")
I have a -404 pcm difference between the k\_effective values for an OpenMC model and a Serpent Model for a HTTR pincell. I am importing the same coordinates for the TRISO fuel locations for both models so I know the packi… --- ## [MCNP5 Error with Thermal Cross Sections](https://openmc.discourse.group/t/mcnp5-error-with-thermal-cross-sections/3912)
**Author:** [@Ld\_83](https://openmc.discourse.group/u/Ld_83)\ **Replies:** 0\ **Last updated:** [February 15, 2024, 11:09am UTC](https://openmc.discourse.group/t/mcnp5-error-with-thermal-cross-sections/3912 "2024-02-15T11:09:52Z")
Hi everyone I’m simulating the impact of moderator temperature on reactor core reactivity using MCNP5. I generated thermal cross sections for light water at 293 K and 350 K using openmc.data.njoy . However, when running… --- ## [Neutron flux and reaction rates discrepancies with MCNP](https://openmc.discourse.group/t/neutron-flux-and-reaction-rates-discrepancies-with-mcnp/3495)
**Author:** [@AmaCha](https://openmc.discourse.group/u/AmaCha)\ **Replies:** 2\ **Last updated:** [January 19, 2024, 2:37pm UTC](https://openmc.discourse.group/t/neutron-flux-and-reaction-rates-discrepancies-with-mcnp/3495 "2024-01-19T14:37:46Z")
Dear experts, I am a new user of OpenMC and I am currently working on benchmarking fluxes, reaction rates and heat loads in the Molten Salt Fast Reactor against MCNP and Serpent2. As expected, using consistent nuclear … --- ## [Sodium Fast Reactor Benchmarks](https://openmc.discourse.group/t/sodium-fast-reactor-benchmarks/1983)
**Author:** [@Denis\_Solovyev](https://openmc.discourse.group/u/Denis_Solovyev)\ **Replies:** 7\ **Last updated:** [December 8, 2023, 2:54am UTC](https://openmc.discourse.group/t/sodium-fast-reactor-benchmarks/1983 "2023-12-08T02:54:18Z")
We computed by OpenMC two 1000 MWt Sodium Fast Reactor Benchmarks (MET-1000 and MOX-1000) with metallic and oxide fuel from NEA/NSC/R(2015)9. For a comparison we use the average value of the benchmark participants and st… --- ## [OpenMC for modeling and simulating SMRs](https://openmc.discourse.group/t/openmc-for-modeling-and-simulating-smrs/3577)
**Author:** [@abdoiz](https://openmc.discourse.group/u/abdoiz)\ **Replies:** 1\ **Last updated:** [October 29, 2023, 4:12pm UTC](https://openmc.discourse.group/t/openmc-for-modeling-and-simulating-smrs/3577 "2023-10-29T16:12:45Z")
I’m looking for any SMR Small Modular Reactors design (NuScale, SMART, etc) benchmark simulated by written OpenMC code. --- ## [Verification of OpenMC TBR evaluation using MCNP as reference](https://openmc.discourse.group/t/verification-of-openmc-tbr-evaluation-using-mcnp-as-reference/3485)
**Author:** [@yogesh](https://openmc.discourse.group/u/yogesh)\ **Replies:** 2\ **Last updated:** [October 20, 2023, 9:31pm UTC](https://openmc.discourse.group/t/verification-of-openmc-tbr-evaluation-using-mcnp-as-reference/3485 "2023-10-20T21:31:57Z")
Hi all, I am a PhD student at University of Tennessee, Knoxville. Right now I am trying to actively learn OpenMC, as an exercise I am conducting a verification study. I am evaluating TBR for multiple solid breeder conce… --- ## [On the Deviation of Results in Using OpenMC to Produce Multi group Cross Sections for Openmoc in the Presence of Vacuum Boundaries](https://openmc.discourse.group/t/on-the-deviation-of-results-in-using-openmc-to-produce-multi-group-cross-sections-for-openmoc-in-the-presence-of-vacuum-boundaries/3498)
**Author:** [@John](https://openmc.discourse.group/u/John)\ **Replies:** 0\ **Last updated:** [October 10, 2023, 7:32am UTC](https://openmc.discourse.group/t/on-the-deviation-of-results-in-using-openmc-to-produce-multi-group-cross-sections-for-openmoc-in-the-presence-of-vacuum-boundaries/3498 "2023-10-10T07:32:13Z")
I need to use OpenMC to create a cross-section library of a single three-dimensional fuel rod for use by OpenMOC. When all boundary conditions are reflection, I can use the cross-section library produced to calculate goo… [Previous page](https://openmc.discourse.group/c/validation-and-verification/8.md) [Next page](https://openmc.discourse.group/c/validation-and-verification/8.md?page=2)