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At least 289 records · Page 16

On the Uranium and Plutonium Nuclear Data Evaluations [Slides]

This presentation provides overviews of uraniums, 233 U and 235 U, plutonium research including motivations, current status in ENDF/B-VIII.0, the inclusion of sub-thermal data, and the inclusion of LANL ratio capture-to-fission data. Additionally, the preliminary fit of Mosby’s data as reported, fluctuating neutron multiplicities, uncertainty in evaluated libraries, and experimental effects are also presented. The presentation concludes by providing a summary of plans for the U and Pu evaluation work.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

SAMMY Modernization Efforts [Slides]

This presentation discusses SAMMY releases and states that all of its dependencies are freely available. It also discusses version control and confirms that versions will be tagged as needed. Additionally, SAMMY program flow is discussed and states that the program flow was improved to allow for easier external access to SAMMY routines. Modernization of SAMMY is continued with the Doppler and Resolution broadening modules. The presentation concludes by stating that documentation updates are in progress.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

Proposed Generalized Header File for TSLs [Slides]

This presentation discusses several recent issues have been raised over the past few years regarding inconsistent definitions for the number of scattering atoms between incoherent elastic and inelastic (MT2 and MT4 files, respectively) in the same MF7 file and isotopic distribution of primary scattering atom. It also discusses how processing codes handle these potential issues in different ways. Additionally, it discusses how the preferred solution would be automation in order to reduce possibility of user error and a proposed solution in the form of a MF7/MT1 file is examined with preliminary examples. The presentation concludes with a question-and-answer discussion.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

Verification and validation testing and tools: comparison between MCNP code versions and nuclear data libraries [Slides]

This presentation discusses the primary goal of software testing which is to test the code for correctness. It also discusses the results for individual suites and the role of validation and verification also referred to in the presentation as V&V. In summation, the V&V framework enables easy comparison between calculations performed with different code versions and/or nuclear data libraries. This entire framework will be distributed with the upcoming MCNP6.3 release. V&V test suites shown and several that were not (Criticality, LAQGSM, Lockwood) will be distributed in the new framework.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

Results and Responses for the 2022 User Forum Survey [Slides]

This presentation discusses the results of a MCNP user survey. Example of questions asked include: "Which MCNP particle types do you typically use?," "What sort of simulations do you run most often?," "Do you build the code?," "Which variance reduction methods do you use?," "Opinions on HDF5," with frequent discussions regarding each question.

96 KNOWLEDGE MANAGEMENT AND PRESERVATION↗

MCNP6.3: A Year in Review [Slides]

This presentation discusses the past year and the many accomplishments of the MCNP6.3 team. It states that the MCNP6.3 release is imminent and that the approved, final documents have been making their way to the website. The code executables and source are already packaged up for distribution and the new installer is being finalized and tested now, for all platforms. The package will be sent to RSICC before the end of October 2022. Additionally, the presentation discusses some things to think about as MCNP6.3 is requested and/or used. For example, many of the recent efforts have been focused on making development, updates, and distribution of the code and documents more robust and streamlined. They will be revising/updating documents more frequently than ever before and they will be exploring avenues to distribute official patches to MCNP6.3. As they explain, this allows them to be more responsive to bugs and issues that are identified. In conclusion, the application of a patch to MCNP6.3 will require having the source code.

96 KNOWLEDGE MANAGEMENT AND PRESERVATION↗

Horizontal Split Table Conceptual Design for Validation of Nuclear Data used in Advanced Reactors [Slides]

This presentation discusses a methodology that was developed to create conceptual designs of benchmark critical experiments for advanced reactors and nuclear data testing. A first concept that was explored was a pebble-bed high-temperature gas cooled reactor, based on the HTR-10 reactor. The very high correlation is a proof of concept that the design is similar to the application, and performing such critical experiments would help nuclear data testing and validation. Other concepts could be explored if needed, such as a molten-salt reactor, a sodium-cooled fast reactor, or heat pipe reactors/microreactor.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗

Covariance Data in Unresolved Range [Slides]

This presentation touches on the covariance data in unresolved range. This presentation talks about how the URR has several limitations and the focus on covariance information. The talk briefly outlines the limitations and fosters a discussion that can lead to format proposals.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

AMPX Support for GNDS-2.1 [Slides]

This presentation is a review of AMPX strategy for GNDS. It includes a summary of point data comparison, Summary of covariance data comparison, and a preview of SAMMY GNDS I/O and other development.

ENDF↗

Continuing Development of the Nuclear Data Processing Code AMPX [Poster]

The ENDF/B-VIII.1 evaluation library has seen a great growth in the thermal neutron scattering sub-library. The SCALE code system has traditionally approached CE transport by assuming that the CE library on disk represented the fully expanded cumulative probability distributions, conditional on exiting angle and marginal on exiting energy. While this is a complete description of the data, it comes at the potential cost of large amounts of on-disk storage. This approach was strained by several TSL files in ENDF/B-VIII.1, such as graphite, which contained data for a large number of Bragg edges. In the fully expanded probability distributions, this was found to be a disproportionately large fraction of the SCALE CE library.

GNDS↗

Comparison Calculations of Subcritical Limits in ANSI/ANS-8.1 [Slides]

The calculations presented in this paper were performed with ENDF/B-VIII.0 and SCALE 6.3.1 to provide users with perspective on what the current k eff values are for the SCLs listed in ANS-8.1. There are multiple SCLs that exceed the reference value of 0.98. This may indicate that these values need to be adjusted by the WG for the next iteration of the standard.

ENDF↗

High temperature nuclear data measurements of SiC, ZrC, and MgO [Slides]

Performed temperature dependent measurements of SiC and ZrC at ARCS instrument at SNS. Performed temperature dependent measurements of SiC, ZrC, and MgO at VISION instrument at SNS. Performed initial atomistic modeling of these materials using various techniques, including machine learned potentials. Future work includes temperature dependent transmission measurements of these materials, as well as improving the machine learned potentials with more training data and different machine learned frameworks.

ARCS↗

Calculations of Subcritical Limits in ANSI/ANS-8.1 [Slides]

ANSI/ANS-8.1 standard “Nuclear Criticality Safety in Operations with Fissionable Materials Outside of Reactors” provides subcritical limit (SCL) values for several single- and multiple-parameter limits for fissile nuclides, including, uniform aqueous solutions and metals containing nuclides of 233 U, 235 U, and 239 Pu, uranium-water lattices, homogeneous uranium-water mixtures of dry/damp oxides, uniform aqueous solutions of low-enriched uranium, and uniform aqueous mixtures of Pu(NO 3 ) 4 containing 240 Pu

ENDF↗

ORNL Testing of Multiple Graphite Benchmarks [Slides]

Integral criticality safety and reactor physics benchmark experiments from the International Handbook of Evaluated Criticality Safety Benchmark Experiments (ICSBEP Handbook) and the International Handbook of Reactor Physics Experiments (IRPhE Handbook) are essential for nuclear data validation and testing

ENDF↗