Is this an operating reactor?

Not yet. It is pre-application development, not an operating product. No microreactor of this class has been built or run at its rated life yet, including ours. Every figure we publish is a design target and every physics result is unqualified screening, pre-QAPD. We label all of it honestly. That discipline is what makes the rest credible.

Why should a regulator or partner take a pre-application program seriously?

Because pre-application is exactly where the credible advanced-reactor cohort is. Part 53 only became final in 2026, the microreactor-specific Part 57 is still a proposed rule, and the leading microreactor developers are all in pre-application or early licensing. We treat the honest labels as milestones on a defined path we are actively executing, not as caveats.

How does HELIX make power without water?

Heat leaves the core through sealed sodium heat pipes, no pumps of any kind and no water anywhere in the primary. A dry supercritical-CO2 Brayton cycle on skids outside the sealed module converts it to electricity, targeting roughly 40 percent net. All heat is rejected to dry coolers, so there is no cooling tower and no water draw against the community that hosts the plant.

What fuel does it use, and can you actually buy it?

UCO-TRISO at 19.75 percent HALEU in a graphite core. It is the only advanced fuel form that is both NRC-precedented and purchasable from multiple US fabricators today. Our screening also shows the core reaches its reactivity limit with most of its uranium unburned, over 90 percent of the U-235 remains, so factory recharge re-banks that reactivity rather than discarding a nearly full fuel load.

How big is a site and how often do you swap the core?

A site numbers up identical sealed modules of roughly 5 megawatts each, one for a hotel or campus, twenty-plus for a hyperscale site. Staggered sealed-core swaps land on a roughly 5 to 7 year cadence and an N+1 reserve module carries an outage, so the modules are multi-year but the site runs indefinitely on rolling factory recharge. Our depletion screening puts module life at roughly four to five full-power years as modeled, likely five to seven once known model conservatisms are removed.

What happens in a total loss of power and cooling?

Nothing that matters. Reactivity self-limits on a strongly negative temperature coefficient, the control drums insert fail-safe by spring and gravity with no power needed, and decay heat leaves by natural-draft air cooling and radiation alone. A total loss of power and cooling is an availability event, not a safety event. There are no pumps anywhere in the reactor, so there is no loss-of-flow accident class, and the safety case never credits a pump, a valve, an operator, or a network.

Can the verification network ever interfere with safety?

No, by construction of the wiring. The attestation layer is classified non-safety and observe-only. It sits behind a hardware one-way path, so it can prove a module is intact but it physically cannot send a command toward a safety system. The safety systems are local and passive and unreachable from any network.

What does "verifiable" actually mean here?

Each module signs its sensor readings and firmware with post-quantum cryptography and anchors them to an append-only log co-signed by independent off-site witnesses. An operator, an insurer, or a regulator can check a module directly rather than take our word for it. Anyone can write the word secure. Only a verifiable reactor lets you check.

How does a fleet catch a problem before it becomes one?

Each site normalizes its performance against its own environment, then the RankShield Network compares every reactor to what its conditions predict. A reactor that drifts from that expectation stands out against an independent-witness fleet. The elegant part is that the same signal flags both wear and tampering, so one detector serves efficiency and security.

What is the licensing pathway?

Our primary target is 10 CFR Part 57, the NRC's proposed microreactor framework (proposed May 1, 2026; final rule expected November 23, 2026). It provides fleet approvals of identical reactors and is aimed at simple machines with simple safety systems, which the pumpless walk-away design is built to fit. Part 53, final since April 2026, remains the backup pathway and our scoping work against it transfers. We claim no approval, and no application is underway.

What still has to happen before you build hardware?

A stood-up NQA-1 quality program, independent physics validation with independent codes and ultimately test data, an NRC license, under Part 57 once the rule is final or under Part 53 as the backup, and validated demand. All of it is defined and stated on our licensing page. We make no economic, schedule, or performance guarantee, only honest labeled progress.

NRC pre-application readiness

The seven topics, answered in one place.

Q: What exactly is RankShield Energy building?

We are developing HELIX, our own sealed, transportable microreactor, targeting the NRC's proposed 10 CFR Part 57 microreactor framework with Part 53 as the backup pathway, with a qualified third-party fabricator manufacturing to our specification. What makes us different is not the reactor. It is that ours can be independently verified. Every module signs its telemetry and is attested from the factory floor to every operating hour.

Before pre-application engagement, the NRC asks a prospective applicant to identify seven things about its program. This page states each of them for HELIX, links to the deeper page where the detail lives, and keeps our honest labels intact: HELIX is at the pre-application stage, and every physics result is an unqualified screening analysis, not credited safety analysis or field data.

We built this page so an NRC reviewer, a prospective partner, or an independent engineer can see the whole readiness picture at once rather than reconstructing it from marketing copy. Nothing here asserts a position we have not earned; where a topic is still being scoped, we say so.

Technology

The reactor, its subsystems, and the safety concept

License class

The kind of license we intend to seek

Regulatory approach

How we will make the safety case

Business model

How HELIX is developed, built, and deployed

Research & development

What has been screened and what is owed

Policy issues

The novel regulatory questions to work through early

Preliminary timeline

The phased path, without committed dates

01 · Technology

HELIX is a sealed, transportable microreactor: a graphite-moderated core of UCO-TRISO fuel at 19.75% HALEU, its heat carried by sealed sodium heat pipes with no pumps of any kind and no water in the primary system, rejecting heat to fully-dry coolers. Reactivity self-limits on a strongly negative temperature coefficient; sixteen boron-carbide control drums and a diverse rod insert fail-safe on loss of power; decay heat leaves by natural-draft air cooling and radiation. A site numbers up identical factory-sealed modules rated 4.40 MWe at the cycle, from one module to twenty-plus. A non-safety, observe-only attestation layer lets an operator, insurer, or regulator independently verify each module without ever being able to command a safety function.

How the reactor works, subsystem by subsystem →
The passive safety case →
Specification and engineering drawings →

02 · License class

HELIX would be licensed as a commercial nuclear power plant, a utilization facility. Our primary target is 10 CFR Part 57, the NRC's proposed microreactor-specific framework (proposed May 1, 2026; final rule expected November 23, 2026), which provides fleet approvals of identical reactors and is aimed at simple machines with simple safety systems, a description the pumpless walk-away design is built to fit. Part 57 is proposed, not final; we hold no approval under it and no application is underway. 10 CFR Part 53, the risk-informed, technology-inclusive framework that became final in 2026, is held as the backup pathway, and the scoping work done against it transfers.

The specific licensing action, under whichever framework applies, is being scoped in our Regulatory Engagement Plan and is a topic we want to align on with NRC staff during pre-application. Separately, any test article would be built under Department of Energy authorization rather than an NRC license, with its quality data credited into the eventual NRC application; that DOE authorization is not itself a commercial license.

03 · Regulatory approach

Our approach is to make a risk-informed safety case on the actual physics of the design rather than force a sodium-cooled microreactor into rules written for large light-water plants. The sequence is scoped to a verified compliance register and includes licensing-basis-event selection, safety classification of every structure, system, and component, a mechanistic source term, functional-containment analysis, and materials qualification under ASME Section III Division 5. A DOE-authorized test unit is structured so its measured data feeds the application, and under the backup Part 53 pathway a phased construction permit with a limited work authorization is available for a first site-anchored submission.

The full licensing pathway, Part 57 primary and Part 53 backup, what is planned and what is owed →

04 · Business model

RankShield Energy is a reactor-design developer. We own the HELIX design and license it, with a qualified third-party fabricator manufacturing to our specification under our quality program. The product is a factory-sealed module and the plant around it; the differentiator is the non-safety verification layer that lets a customer, an insurer, or a regulator independently check a unit rather than take our word for it.

The target application is firm, carbon-free power delivered where it is needed: data centers, industrial process loads, and remote or defense sites that need reliable on-site power. We are deliberate about what we do not claim. We make no capital-cost, levelized-cost, schedule, or performance guarantee. The design targets a mid-grade cost position and spends deliberately on safety, efficiency, and longevity rather than trying to be the cheapest option. Any hardware commitment is gated on validated demand.

On economics, stated plainly

We publish no economic projections. A first-of-a-kind advanced reactor that promises a specific cost is making a claim it cannot yet support. Our commitment is honest, labeled progress toward a licensable, buildable design.

05 · Research and development activities

Done: the design of record was consolidated and its sourced claims adversarially verified; continuous-energy Monte Carlo screening (OpenMC with ENDF/B-VII.1) covered criticality and core sizing, reactivity-limited lifetime, temperature feedback, shutdown margin, and post-trip xenon. In progress: a six-family real-life scenario register and the failure campaign, including the structural and thermal finite-element stand-up (MOOSE-class tools) needed for the destructive boundary. Owed: a stood-up NQA-1 quality program, independent physics validation with independent codes and ultimately test data, materials qualification, and a DOE-authorized test unit. Every result produced to date is unqualified screening, an input to design, not credited analysis.

The validation program and the failure campaign →

06 · Policy issues

We would rather surface the novel regulatory questions early than discover them late. The ones we see for a design of this class are:

HALEU fuel. Security category and safeguards treatment for 19.75% HALEU in a microreactor.
Non-light-water coolant. Regulatory treatment, phenomena, and source term for a sealed sodium heat-pipe system under the Part 57 and Part 53 frameworks.
Factory-sealed, transportable modules. Fabrication under NRC oversight, transport of a sealed unit, and site acceptance of a module built elsewhere.
Emergency planning. How a mechanistic source term and functional containment support a right-sized emergency planning zone.
Staffing and operations. Control-room staffing and remote-monitoring expectations for a small, passively-safe, multi-module plant.
The verification layer. Classification of a networked digital attestation layer as non-safety and observe-only behind a hardware one-way path, and its cyber-security treatment.
Physical security and multi-module siting. Right-sizing physical protection and licensing a number-up fleet of identical modules on one site.

None of these is a reason the design cannot be licensed. They are the conversations we want to have with NRC staff during pre-application so the eventual application resolves them rather than raises them.

07 · Preliminary timeline

We publish a phased path rather than committed dates. Stating a firm schedule for a first-of-a-kind reactor would be the kind of unbacked claim this whole program is built to avoid. The sequence, with each phase gated on the one before it, is:

NOW

Phase 0: Pre-application preparation

Design of record consolidated and adversarially verified; core reactor-physics screening runs complete, with named re-runs (including heat-pipe void geometry) still pending; the proposed Part 57 microreactor framework identified as the primary licensing target with Part 53 as backup; the request for initial NRC engagement is being prepared and has not yet been made. All results are unqualified screening (pre-QAPD).

Phase 1: Quality program & design maturation

Stand up an NQA-1 quality-assurance program; mature the design toward a licensing basis; develop the Regulatory Engagement Plan and the topical-report sequence.

THEN

Phase 2: Independent validation & test data

Confirm the physics with independent codes and, ultimately, test data; structure a DOE-authorized test unit so its NQA-1 data credits into the commercial case; qualify materials.

THEN

Phase 3: NRC application

Submit under 10 CFR Part 57 once the rule is final, or under Part 53 as the backup pathway. The specific licensing action is being scoped in the Regulatory Engagement Plan.

GATED

Phase 4: Construction & first operation

Contingent on successful licensing, independent validation, and validated offtake demand. We publish no committed dates and make no schedule guarantee.

Readiness posture

HELIX is in active pre-application development, targeting the NRC's proposed 10 CFR Part 57 microreactor framework with Part 53 as the backup pathway. Every figure is a design target; every physics result is unqualified screening (pre-QAPD). The remaining path is defined and stated: a stood-up NQA-1 quality program, independent validation, NRC licensing, and validated demand.

RankShield Energy · HELIX · pre-application

Contact the program to begin engagement →