MOLTSA – Molten Salt Thermochemical Data Platform

MOLTSA is an open, web-based R-Shiny application for accessing, visualizing, and analyzing thermochemical data relevant to molten salt reactor research. It overlays literature datasets with CALPHAD-modeled properties (e.g., phase equilibria and $\Delta _{mix} H$) and provides utilities that shorten the path from experimental data to validated thermodynamic model inputs.

A live development of the application is available at: http://moltsa.com

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Key capabilities

Visualization

• Interactive pseudo-binary phase diagram viewer with experimental/model overlays and export functions
• Interactive enthalpy of mixing plots with linked metadata tables
• 3D ternary / pseudo-ternary viewer supporting FactSage® .fig files and experimental data overlays

CALPHAD-adjacent utilities

• Optimizer-file retrieval (FactSage Optimizer-compatible)
• δ₁₂ parameter calculation for liquid–liquid $\Delta _{mix} H$ correlations
• Heat capacity fitting (piecewise Maier–Kelley coefficients directly usable in Gibbs free energy minimization codes)
• DSC/thermal analysis tools (temperature calibration, uncertainty propagation, application of the IUPAC zero-rate method)

FAIR-aligned data

• Curated CSV/JSON thermochemical datasets with traceable metadata
• Validation at ingest + unit/basis harmonization designed for CALPHAD

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Repository structure

• app.R – application entry point (launches the golem app)
• DESCRIPTION, NAMESPACE – package metadata and dependency declarations
• R/ – Shiny modules + helpers + compute/services
• inst/ – internal package resources (assets/templates, as applicable)
• data/ – packaged data objects
• dev/ – development scripts (utilities)
• man/ – documentation generated from roxygen2
• .Rbuildignore, .gitignore – build/deploy/version-control ignores
• README.md – readme file for moltsa

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Local installation

For most users, the hosted deployment at moltsa.com is the preferred access route; local installation is primarily intended for development or offline use. A local build of MOLTSA requires installation of the R programming language and some R packages.

Windows

Prerequisites

Install the following:

• R (version 4.3 or later recommended)
• RStudio (optional, but helpful)
• Rtools for the installed R version

Installation steps

1. Clone or download the repository.
2. Open R or RStudio in the project directory.
3. Install required R packages:

install.packages(c("remotes", "pkgload"))  
remotes::install_deps()

4. Load the application package and launch the app:

pkgload::load_all()  
run_app()

The app will open in a web browser, or provide the local URL if it does not open automatically.

Notes

• If local installation is not desirable, users can access the deployed version of the application directly at moltsa.com.

Linux

1) Install R

sudo apt install r-base

2) Install system dependencies

sudo apt update
sudo apt install -y \
  build-essential \
  cmake \
  pkg-config \
  libuv1-dev \
  libssl-dev \
  libcurl4-openssl-dev \
  libxml2-dev

2) Clone repository

git clone https://github.com/JackAnthonyWilson/MOLTSA.git
cd MOLTSA

3) Install R dependencies and run locally

in R:

install.packages(c("pkgload", "remotes"))  
remotes::install_deps()  
pkgload::load_all()  
run_app()

If you are running WSL and do not have a browser installed, paste the port directly into your browser in Windows. i.e., when you see:

Listening on http://127.0.0.1:XXXX

go to your browser and input

http://localhost:XXXX

Notes

• If local installation is not desirable, users can access the deployed version of the application directly at moltsa.com.

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R package dependencies

Declared in DESCRIPTION under Imports::

• blastula
• bs4Dash
• config
• data.table
• dplyr
• DT
• glue
• golem
• highcharter
• htmlwidgets
• janitor
• keyring
• plotly
• rhandsontable
• shiny
• shinycssloaders
• shinymanager
• shinythemes
• shinyWidgets
• Ternary

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Usage overview

MOLTSA is organized individual modules, including:

• Phase Diagrams – pseudo-binary phase equilibria data with literature/model overlays
• Enthalpy of Mixing – experimental $\Delta _{mix}H$ data visualization with modeled values
• Ternary .fig Viewer – interactive 3D phase equilibria viewer and (FactSage® .fig + optional experimental CSV overlays)
• Optimizer Files – search/filter/download optimizer files
• Parametric Descriptors – δ₁₂ calculator
• Heat Capacity – Maier–Kelley parameter fitting
• DSC Tools – calibration, uncertainty propagation, and application of the IUPAC zero-rate method

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Data policy and attribution

MOLTSA stores extracted numeric datasets and metadata (CSV/JSON) and does not store or redistribute copyrighted full-text content (e.g., PDFs). Attribution is maintained for all datasets (including DOI where available), and takedown/removal is supported upon rights-holder request. The full privacy policy is hosted on a static webpage at moltsa.com/privacy-policy.html

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License

Released under GPL-3.0 (see LICENSE / LICENSE.md).

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Citing MOLTSA

If you used MOLTSA, please consider citing:

J. A. Wilson et al., “MOLTSA: An R Shiny Platform for Molten-Salt Thermochemical Data Management, Analysis, and Assessment", Journal of Open Research Software, vol. 14, no. 1, Apr. 2026, doi: 10.5334/jors.685.

Contact

Developer: Jack A. Wilson
Email: jackwilson.mchem@gmail.com