What exactly is RankShield Energy building?

We are developing HELIX, our own sealed, transportable microreactor, and licensing it under 10 CFR Part 53 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.

Is this an operating reactor, or a study?

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, 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 low-pressure sodium with no water anywhere in the primary. An air-cooled organic Rankine cycle converts it to electricity for the first units, with a funded supercritical-CO2 upgrade path later. 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. We also designed a multi-batch factory recharge that reuses partially burned fuel, which cuts how much fresh HALEU each swap needs by roughly three times.

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

Two to four sealed modules per site produce 10 to 16 megawatts of electricity. We run each module at 76 to 95 percent of rating so staggered core swaps land on an 8 to 10 year cadence, and reserve margin carries a module outage. Our own depletion screening supports that lifetime target.

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 circulation alone. A total loss of power and cooling is an availability event, not a safety event. 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?

We elected 10 CFR Part 53, the risk-informed framework that went final in April 2026. We scoped the topical-report sequence to a verified compliance register and are structuring a DOE-authorized test unit so its data, collected under NQA-1 from day one, credits into the commercial case.

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 53, 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.

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 a pre-application design study, every figure is a design target, 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, cooled by low-pressure sodium with 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 circulation. A site runs two to four factory-sealed modules for 10 to 16 MWe. 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, under 10 CFR Part 53, the NRC's risk-informed, technology-inclusive framework for commercial nuclear plants, which became final in 2026. We have elected Part 53 as the class of license we intend to pursue.

The specific licensing action within Part 53, for example a construction permit followed by an operating license, or a phased submission paired with a limited work authorization, 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 Part 53 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 a phased construction permit with a limited work authorization is available for the first site-anchored submission.

The full Part 53 pathway, what is elected, planned, and 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 low-pressure sodium system under Part 53.
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 two to four 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

Design of record consolidated and adversarially verified; reactor-physics screening complete; Part 53 elected; initial NRC engagement requested. 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: Part 53 application

Submit under 10 CFR Part 53. The specific action (for example a construction permit followed by an operating license, or a phased submission with a limited work authorization) 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 under 10 CFR Part 53. 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 →