v2.0.0 in development — Christmas 2026

GROVES

Desktop Nuclear Reactor Input Editor

GROVES is undergoing a serious quality overhaul. Public downloads are paused while we rebuild it to the standard the rest of the BelvoirDynamics line holds; it returns as v2.0.0, targeted for Christmas 2026. In the meantime, OWEN for VS Code and Cursor covers the same four codes with the same validators and converter.

Air-gap-friendly PySide6 desktop editor for MCNP, OpenMC, Serpent, and SCONE input files. The current source line (v1.4.1) brings the 3D preview to OWEN parity: all four geometry parsers ported, so a BEAVRS Cycle-1 full core resolves at its real 55,849 primitives (170,419 in Serpent) and renders in about a second, with axial pin stacks and a slice slider. On top of live on-type validation with the full OWEN rule set, built-in pure-Python MCNP workspace validation (no Node.js), NRDP material insertion, in-app search over every reactormc.net tutorial, and deck-aware ALLEN nuclide detection — plus the visual lattice editor, hi-fi cross-code conversion (MCNP↔OpenMC stable), results viewer, sweep dashboard, PNNL-15870 materials, and OpenMC geometry verification. A BelvoirDynamics product.

MCNP workspace validation

File → Open MCNP Project or GROVES → Validate Workspace — cross-file checks across read/copy includes (undefined references, duplicate definitions, include cycles); Problems panel with double-click goto. Pure Python and built in since v1.4.0 — no Node.js required; runs on a background thread with progress.

Syntax highlighting

Four palettes (Classic, Solarized, High Contrast, Pastel) for MCNP, OpenMC, Serpent, and SCONE via QSyntaxHighlighter.

Deep validation

Per-language diagnostics: MCNP ZAID/suffix, density sign, mt/S(α,β), macrobody counts; OpenMC IndependentSource/RectangularPrism API; Serpent cuboid/omp; SCONE aceNeutronDatabase and pinUniverse rules.

MCNP reference tracker

F12 go-to-definition, Shift+F12 find references, hover tooltips, docked cross-reference tree — role-aware for cells, surfaces, materials, universes, fill, and trcl.

MCNP line-length guard

Column-80 ruler, Problems-panel overlength diagnostics, invisible-character toggle.

3D geometry preview

PyVista/VTK with NumPy-instanced meshes — a 55,849-primitive BEAVRS core builds and renders in about a second. Component, material, and axial-layer toggles with solo/isolate, Auto/Disc/Layers fidelity, axial pin stacks and slice slider, BEAVRS radial structure, hover inspect, distance/angle/radius tools, 1.5M instance budget.

Input Builder + lattice

Snippet wizards for materials, surfaces, cells, sources, and settings — plus an integrated Lattice tab with a visual pin-map grid editor (W 17×17 / BWR presets). Toolbar and menu Lattice Builder shortcuts open Input Builder on the Lattice tab.

Prebuilt models

BEAVRS Cycle-1 full core (193 assemblies) and 17×17 assembly starters for all four codes; reflected UO₂ pin-cell teaching decks.

Cross-code converter

Hi-fi MCNP→OpenMC (OWEN v0.3.8 parity): boolean regions, macrobodies, universes/lattices, graveyard→vacuum, S(α,β), tmp, kcode/ksrc, FMESH + F4/F6/F7; legacy fallback; MCNP→Serpent/SCONE experimental.

OpenMC geometry verify

Overlap scan (slice plots with show_overlaps) and lost-particle probe via your Python install — validate converted decks before you run.

Run simulation

Launch MCNP, OpenMC, Serpent, or SCONE from the editor; live output stream; configurable executable paths in Settings.

Parametric sweep

JSON sweep manifest, per-run input mutation, output capture, k-eff parsing, TSV summary, and matplotlib sweep dashboard over run directories.

Results viewer

k-eff convergence, flux spectrum (log-log), tally table, mesh-tally heatmap — parsers for OpenMC statepoint, MCNP mctal, Serpent _det.m, SCONE outputs.

ALLEN cross-sections

Toolbar ALLEN opens the embedded matplotlib σ(E) panel — deck-aware nuclide detection (full element table, SCONE bare ZAIDs), six selectable reactions, full-library nuclide picker, Doppler Studio (multi-temperature overlay, RI readout), disk cache, and browser fallback when offline. GROVES menu adds ALLEN in Browser for reactormc.net/nrdp/allen.

PNNL-15870 materials

Insert PNNL Material picker — 411 Rev. 2 compendium entries with per-code card preview (MCNP, OpenMC, Serpent, SCONE).

Menu UX (source)

GROVES menu grouped into Validate, Build, Simulate, Tools, and Settings; tab-required actions gray out when no editor tab is open; 3D Geometry Preview switches the main 3D Preview tab.

Templates & themes

Bundled starters: pin cell, assembly, quarter-core, BWR bundle. Seven UI themes — Dark (default), Marble, Rome Marble, Gold, Ocean, Forest, Slate — in Settings and the toolbar.

Settings

Highlight palette, line-length limit, solver executable paths, and theme selection in one dialog.

Community Library

Opt-in Supabase community model browser — disabled by default; fully offline when not enabled.

Windows 10/11 64-bit • Linux and macOS on the roadmap

BelvoirDynamics emerald branding • A BelvoirDynamics Product | ReactorMC

Where can I download GROVES?

Public installer downloads are paused. Earlier 1.x installers were withdrawn because they did not meet the quality bar we want a desktop product to carry, and we would rather ship nothing than ship something rough.

The rebuild lands as v2.0.0, targeted for Christmas 2026, with signed Windows installers and SHA-256 checksums on GitHub Releases as before.

Until then, OWEN provides the same validators, converter, 3D preview, and results tooling inside VS Code and Cursor, and NICHOLS covers Sublime Text and Notepad++ highlighting.

Security & Verification

GROVES does not collect or transmit any data. No telemetry, analytics, or network calls. Your input files stay on your machine.

Air-gapped use: when v2.0.0 ships, download the installer on a connected machine, verify the published SHA-256 checksum, then transfer via USB or approved media. GROVES runs fully offline after installation.

If your organization handles sensitive or export-controlled nuclear data, follow your internal policies for software approval.

Roadmap

GROVES 2.0.0 — Christmas 2026

The 2.0.0 release is a ground-up quality pass over the existing feature set: stability, polish, and consistency before new capability. Windows first; Linux and macOS builds stay on the roadmap — the underlying stack (Python, PySide6, PyVista) is portable, and the PyInstaller build pipeline is being adapted for the additional targets.

Linux desktop build

Ubuntu / Fedora packages with the same PyVista 3D viewer and lattice builder. Targeted after the OWEN VS Code extension reaches feature parity for the most-used workflows.

macOS desktop build

Apple Silicon and Intel builds. Demand-driven — reach out via the contact points on the BelvoirDynamics page if your workflow needs it.

Looking for the editor extension? — OWEN for VS Code

OWEN brings language-server diagnostics, cross-code converter, ALLEN Doppler Studio, 3D geometry preview, lattice builder, prebuilt BEAVRS models, and simulation automation into VS Code and Cursor. Stable release, v1.1.6.

GROVES 2.0.0 will remain the recommended choice for air-gapped, fully-offline workflows.