Nuclear Design Bureau Release Date and Early Access Roadmap

The Nuclear Design Bureau release date is September 2026, and the exact reading depends on which clock you use: the Steam store lists September 14, 2026, while SteamDB records the store release at 05:05 UTC on September 15, 2026. Either way, this is a very fresh Early Access release, and the pace of patches since launch is the more useful fact for anyone deciding whether to start now. Below is the launch record plus what the developer has committed to add.

The Release Date and Launch Facts

The launch landed on Steam for Windows at $9.99 from Design Bureau KB-11, which is both the developer and the publisher. Trackers show no discount history since, so the listed price is the price.

Fact	Detail
Early Access release	September 2026; Steam lists September 14, SteamDB timestamps the store release at 05:05 UTC on September 15
Price	$9.99, also recorded as the lowest price since release
Platform	Windows on Steam
Developer and publisher	Design Bureau KB-11
Store genres	Indie, Simulation, Strategy, Early Access
Store features	Single-player, Steam Achievements, Steam Cloud, Family Sharing

• The store page opens with an Early Access warning about bugs, freezes and crashes, and notes that the game is compute heavy.
• The same notice states that the game uses WebGPU and Electron and that Linux, Proton and macOS are not officially supported yet.
• The page discloses the use of AI-assisted images, text and code during development, with all content reviewed and edited by the developer.
• SteamDB first recorded the app on Steam in November 2025, so the gap from listing to launch was under a year.
• English is the only supported language, and the store carries a General Mature Content descriptor.

Patches Since Launch

The post-launch cadence is the strongest signal of how actively this build is changing. Three separate notes appear in the first three weeks: a hotfix on September 15, a physics and campaign patch on October 1, and a hotfix on October 2.

Patch	Documented changes
Hotfix, September 15	Early post-launch fixes
Physics patch, October 1	Fissile material resists compression more, so yields change; neutron leakage out of LiD and DU fixed; hot gas expansion fixed; fusion yield now shows the percentage of fuel burned; simulation failures no longer block a restart
Hotfix, October 2	Large designs speed up and second-stage burn is faster; a fusion-material crash case fixed; UI and telemetry fixes; campaign dialog fix

• The October 1 patch is the one to read before trusting an old design, because it explicitly says yields will change.
• The October 2 hotfix states that the previous build is available on a previous branch on Steam, which is a usable rollback path if a patch misbehaves.
• Patches have also touched the criticality lab and the detonation readouts, so instruments can change between sessions.
• Because the developer says the physics, tools and campaign respond to player feedback, patch notes are effectively part of the design documentation.

The Early Access Roadmap and 1.0

No 1.0 date exists yet. What exists is a roadmap the developer labels as subject to change, split across physics, campaign and content, presentation, and community features. That means the reasonable expectation is a long Early Access period rather than an imminent full release.

Roadmap area	Planned additions
Physics and simulation	Refined detonation viewer with better shockwaves, damage radius and thermal radiation, destructible buildings and targets, finer grid resolution, more to do in the criticality lab
Campaign and content	Expanded campaign with unique challenges, many more directives, a voiced campaign, additional device concepts, more advanced materials
Presentation and audio	More music tracks
Community and meta	A public leaderboard and statistics on every campaign directive for comparing design efficiency

Reception so far is mixed-to-positive rather than rapturous. SteamDB records the positive share in the low seventies across roughly 358 reviews, and player tracking sites report a 75% Mostly Positive score with an all-time peak of around 505 concurrent players shortly after launch. Reviews that criticise the game focus on editor usability and simulation performance rather than the concept, which is consistent with a build the developer describes as still being shaped. For what that concept actually asks of you, see the guide page, and for missing hardware quirks such as Steam Deck status, see the steam page.