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SoftFission gives you a private on-demand compute workflow for OpenMC: create a project, prepare files, reserve a compute node, submit runs, and keep results in persistent storage.

Workspace Compute node OpenMC

Compute

Private

Each user works on a personal compute node rather than a shared interactive machine.

Billing

Reserved

Credits are charged only when the compute node is ready, not while it is still being created.

Storage

1.00 GB

Persistent project storage is separate from compute activity and remains available between runs.

What SoftFission does

The platform is designed for structured reactor-physics workflows, starting with OpenMC.

SoftFission combines a personal workspace, persistent project files, and an on-demand private compute node. File editing, uploads, downloads, and other front-node actions are not billed as compute activity.

The current MVP is OpenMC-first. Users create projects, prepare XML and related inputs, submit scheduler-managed jobs, and inspect outputs and logs inside the same workspace.

Getting started

A typical first run on SoftFission follows this sequence.

1. Sign in

Access your personal workspace and account balance.

2. Create project

Start an OpenMC project and keep your model inputs organized in one place.

3. Prepare files

Upload or edit input files such as XML models and related text files.

4. Reserve compute

Choose a maximum reserved duration for your private compute node.

5. Submit run

Launch the calculation only when the selected walltime fits inside the remaining reserved duration.

6. Inspect results

Review logs, outputs, and run snapshots, then download results when needed.

Compute node and credits

The compute node uses reservation-based prepaid billing, with the charge applied only after the node becomes ready. New users receive 4 free credits on first sign-in.

When you start creating a compute node, you select a maximum reserved duration. SoftFission checks that your balance is sufficient, but no credits are charged yet.

When the node becomes ready, the full reserved amount is charged. The price is 1 credit per started hour of compute-node activity.

If you delete the compute node early, unused reserved credits are returned to your account.

You can extend the reserved duration at any time by reserving additional credits.

The compute node is deleted automatically after 1 hour without queued or running compute jobs. The compute node is also deleted when the reserved duration expires.

Projects, files, and runs

Workspace actions and compute actions are treated differently.

Project storage	Each user has 1.00 GB of persistent storage for project inputs and results.
Editing files	Editing text files in the workspace does not count as compute activity.
Uploads and downloads	Moving data in or out of the workspace is a front-node action and is not billed as compute.
Run submission	A compute job may be submitted only if its selected walltime fits inside the remaining reserved duration.
Run records	Run snapshots, logs, outputs, and download packages help keep work reproducible and organized.

Walltime and runtime guidance

OpenMC runtime is uncertain, so planning jobs conservatively matters.

SoftFission does not guarantee that a calculation will finish inside the selected walltime.

If a job exceeds its selected walltime, the scheduler stops it automatically.

When runtime is uncertain, first run a smaller test calculation to estimate performance before launching a larger production case.

A conservative walltime choice is usually safer than an aggressive estimate for long Monte Carlo runs.

OpenMC on SoftFission

SoftFission provides the environment around the code rather than replacing upstream documentation.

Current scope

OpenMC is the first supported code in the platform workflow.

Future direction

Starter projects, reusable templates, and example cases can be added later.

Official documentation	docs.openmc.org
Source repository	github.com/openmc-dev/openmc
SoftFission role	Workspace, file handling, reservation-based compute access, run organization, and result storage.

Frequently asked questions

Short answers to the main operational questions behind the MVP.

Do I pay while editing files?

No. File editing, uploads, downloads, and other front-node activities are free and do not count as compute activity.

When does billing begin?

Billing begins only when the compute node is ready, not when you first click to start it.

What happens if I stop the node early?

The unused portion of the reserved credits is returned to your account.

Can I submit any job walltime I want?

No. The selected walltime must fit inside the remaining reserved duration of the compute node.

Will OpenMC always finish before walltime?

Not necessarily. Runtime cannot be predicted exactly, so long jobs should be sized conservatively and tested on smaller cases first.

What if I leave the node idle?

The node is automatically deleted after 1 hour without queued or running compute jobs.