Technical papers

Who Inspects a Reactor Built in a Factory? Verification of Off-Site Fabrication

Published September 1, 2026 · By Jamie Kloncz, Founder, RankShield Energy

HELIX microreactor, concept render
HELIX microreactor, concept render. RankShield Energy is at the pre-application stage; this depicts a design under development, not an operating facility.

Technical paper · document control

Document type
Technical paper
Version
1.0
Published
September 1, 2026
Revised
September 1, 2026
Status
Verification analysis of off-site fabrication, open for comment
Regulatory status
RankShield Energy is a pre-applicant engaged in early regulatory interaction with the U.S. Nuclear Regulatory Commission. RankShield Energy holds no NRC license, permit, or design approval. No RankShield Energy design, product, or facility, and no safety, performance, or operational characteristic of one, has been demonstrated to or accepted by the NRC. Descriptions of design behavior are design intent and are subject to analysis, testing, and regulatory review.

Abstract

Factory fabrication is one of three defining features of the microreactor class in the Department of Energy program plan, and the premise moves construction of the reactor off the site it will operate on. The oversight instruments most discussed attach to an operating site. The build phase therefore carries the least site-attached oversight and the most consequence, and it is the phase in which a downstream party has the least direct evidence. This paper examines the instrument the framework in force provides for verifying off-site construction, the inspections, tests, analyses, and acceptance criteria required in a manufacturing license application by 10 CFR 52.158, and observes that the microreactor rule now proposed sets that instrument aside.

Proposed 10 CFR Part 57 (a proposed rule published in the Federal Register on May 1, 2026, with the comment period closed on June 15, 2026; not final, and no developer is licensed under it) contains a manufacturing-license subpart covering fabrication, factory fuel loading, transport, and site acceptance. The NRC gives its reasons and invites comment on streamlined constructs. This paper answers that invitation structurally: it decomposes the verification functions the existing construct performs in an off-site build, identifies which remain load-bearing when a whole reactor rather than a module is built off site, and sets out what a records-based construct would have to supply in their place. The principal limitation is authorship. RankShield Energy does not manufacture reactors, and the argument is an architecture argument rather than a manufacturing one.

This paper is technical analysis prepared for a professional audience. It is not legal, regulatory, engineering, or investment advice. It does not interpret regulatory requirements on behalf of any third party. Where this paper describes a proposed rule, the rule is not final and may change. Readers responsible for regulatory decisions should rely on the primary sources cited rather than on this summary of them.

Scope and limitations

This paper addresses how a reactor manufactured away from its operating site is verified, which published instruments reach the manufacturing facility, what the proposed microreactor framework would do differently, how transport sits between the two quality assurance boundaries, and what a records-based verification construct would have to provide to serve the functions the existing construct serves. It draws on primary sources spanning the regulator, the Government Accountability Office, the NRC Office of the Inspector General, the Department of Energy and five national laboratories, and the standards bodies. The audit finding recorded in section 4 is a 2012 finding and is labeled as such there. Where a document is characterized, it is cited and its status is stated: rule in force, proposed rule, staff paper, contractor report, or audit finding.

Several things are deliberately out of scope. The paper does not tell any party what a rule requires of it. It contains no design detail for any RankShield Energy system: no geometry, no fuel description, no enrichment figure, no performance or lifetime figures. It contains no cost or economic analysis. It does not name, rank, or characterize other developers. It does not describe unattended operation of a reactor. It does not quote from the body of any staff paper, inspection manual chapter, or program plan document whose full text sits outside the verified source set; those documents are named by title and date and described in terms their titles and the agency's own summary pages support. It draws no conclusion about the diligence of any agency, office, or vendor from the dated facts recorded in section 4.

Several developments would change the analysis materially and should trigger a revision: a final microreactor licensing rule, or withdrawal or material amendment of the proposal; a published agency position on what a streamlined construct for verifying off-site manufacture would consist of; a final rule following the NRC's proposed rule on package certification requirements (a proposed rule published in the Federal Register on July 27, 2026; a proposed rule that is not final); new national-laboratory results that change the transport dose or criticality picture; or any agency statement addressing the evidentiary status of machine-generated manufacturing records. Amendment of the licensing and oversight rules through the NRC's proposed rule modernizing reactor licensing, safety oversight, and siting practices (a proposed rule published in the Federal Register on July 16, 2026 at 91 FR 44560; not final), which touches 10 CFR Parts 2, 50, 51, 52, 53, 54, 71 and 100 [39], would also bear on it. The decomposition in section 7 is our reading of the cited record and is offered for disagreement rather than for adoption.

A microreactor is defined in the public record partly by where it is built. The Department of Energy program plan lists factory fabrication as one of three defining features of the class [31]. That premise moves the construction of a reactor off the site it will operate on and into a facility the site licensee does not run, that a downstream party cannot walk through, and that the regulator reaches by a route different from the one it uses at a construction site. The question this paper asks is narrow and practical: who verifies that build, and what does a party who was not present get to rely on afterwards?

The method is a decomposition rather than a survey. Section 1 sets out why the build phase is structurally different from the operating phase. Section 2 describes the instrument the framework in force provides for it, the manufacturing license at 10 CFR Part 52 Subpart F [1]. Section 3 describes what inspections, tests, analyses, and acceptance criteria actually do, because the machinery is more specific than the acronym suggests [4][5]. Section 4 describes how the regulator reaches a factory today, through the vendor inspection program [10]. Section 5 sets out what the proposed microreactor framework would do and what it sets aside. Section 6 treats transport as a custody interval [20]. Section 7 is the contribution. Section 8 applies the analysis to RankShield Energy.

Two framing rules govern what follows. Anything in force is identified as in force, and anything proposed is identified as proposed at every mention, including proposed 10 CFR Part 57 (a proposed rule published in the Federal Register on May 1, 2026, with the comment period closed on June 15, 2026; not final, and no developer is licensed under it) [19]. Staff papers are staff analysis rather than Commission positions and are identified as such wherever they are named. RankShield Energy is a pre-applicant in early regulatory interaction with the NRC, holds no NRC license, permit, or design approval, and does not operate a manufacturing facility. The analysis in section 7 is offered as a contribution to an open regulatory question the agency has itself put out for comment. It is not a proposal this paper claims the agency should adopt, and it is not a description of a product.

Key takeaways

  • The build phase of a factory-fabricated reactor carries the least site-attached oversight and the most consequence, and an Oak Ridge National Laboratory contractor report states that factory fueling and assembly, multi-site operation, and the associated transportation have not been demonstrated under Nuclear Regulatory Commission rules and regulations.
  • The framework in force already contains an instrument aimed at off-site construction: a manufacturing license application must contain inspections, tests, analyses, and acceptance criteria sufficient to assure that the reactor has been manufactured in conformity with the manufacturing license, so that construct is not confined to combined licenses.
  • Proposed 10 CFR Part 57 (a proposed rule published in the Federal Register on May 1, 2026, with the comment period closed on June 15, 2026; not final, and no developer is licensed under it) contains a manufacturing-license subpart covering fabrication, factory fuel loading, transport, and site acceptance, and the NRC states that it did not pursue a combined license approach because those inspection and acceptance requirements were designed for light water reactors and the associated closure hearing could extend the licensing timeline.
  • Transport is a custody interval in which the unit sits outside the manufacturing facility's quality assurance boundary and is not yet inside the site's, and the proposed rule would require verification of the condition of shipped items on receipt without specifying what that verification rests on.
  • Nothing in 10 CFR Part 21, Appendix B to 10 CFR Part 50, 10 CFR Part 52, or the proposed microreactor framework references machine-verifiable attestation, and a developer arguing for a records-based construct has an obvious interest in preferring one.

1. The phase with the least oversight

Oversight of a power reactor in the United States is usually discussed in terms that presume a site: a licensee, a fixed location, and a regulator with a physical route to it. The rule governing inspection during construction is written around a licensee that notifies the Commission as it completes acceptance criteria at the place the plant is being built [4]. Our starting observation is that the microreactor premise breaks that presumption, and breaks it at the phase where the material condition of the machine is established. When the reactor is built where it will run, site-attached oversight and construction oversight are the same thing. When the reactor arrives on a truck, they are not.

The premise is explicit in the federal record. The Department of Energy program plan, prepared through Idaho National Laboratory, lists factory fabrication as one of three defining features of the class and states that the majority of components of a microreactor are anticipated to be fully assembled in a central factory and shipped out to the locations of operation [31]. A Pacific Northwest National Laboratory report prepared under a prototype microreactor transportation safety program describes microreactors as factory-fabricated and designed to be easily transportable by truck, rail, vessel, or air [24]. An Idaho National Laboratory assessment published in Nuclear Technology examined factory fabrication considerations for the class directly [29], and an earlier laboratory regulatory and licensing strategy for microreactor technology set out the regulatory questions the class raises [33].

Oak Ridge National Laboratory, in a contractor report supporting the development of guidance for microreactor manufacturing licenses, states the position plainly: factory fueling and assembly, multi-site operation, and the associated transportation of advanced nuclear systems present both new opportunities and challenges, and these areas have not been demonstrated under Nuclear Regulatory Commission rules and regulations [30]. That is the honest frame for this paper, and it is a contractor to the regulator saying it. Off-site construction itself is not novel to the agency: Brookhaven National Laboratory assessed modular construction for safety-related structures at advanced nuclear power plants for the NRC in 1997 [32]. What changes is the fraction of the plant that moves off site, and with it the fraction of the verification record that has to travel.

Statute has recognized the sequencing problem. The ADVANCE Act directs microreactor strategies in eight areas, among them oversight and inspections and the transportation of fueled microreactors, as the agency records on its microreactor regulatory activities page [15]. The build phase is where the material condition of the reactor is established, and it is the phase in which a downstream party, whether a site licensee, a lender's technical adviser, an insurer, or a host community, has the least direct evidence. Our companion analysis of oversight models for fleet-scale deployment treats the operating end of the same problem. This paper treats the build end.

2. The instrument that exists: the manufacturing license

The framework in force does contain an instrument built for this situation. 10 CFR Part 52 Subpart F provides for a manufacturing license [1]. Under 10 CFR 52.151 the license authorizes the manufacture of nuclear power reactors to be installed at sites not identified in the manufacturing license application [2]. That is precisely the factory case. The instrument is bounded. 10 CFR 52.153 provides that a reactor manufactured under a manufacturing license may only be transported to and installed at a site for which either a construction permit under Part 50 or a combined license under Subpart C of Part 52 has been issued [1]. A manufacturing license does not create a place to put the reactor.

The application content is where the verification intent shows. 10 CFR 52.157 requires design information sufficient to permit the Commission to judge the applicant's proposed means of assuring that the manufacturing conforms to the design, and sufficient to permit the preparation of acceptance and inspection requirements by the NRC [1]. Those two clauses state the whole verification problem in a sentence: a means of assurance held by the applicant, and a basis on which the regulator can write its own inspection requirements. 10 CFR 52.158 then requires the application to contain inspections, tests, analyses, and acceptance criteria sufficient to assure that the reactor has been manufactured in conformity with the manufacturing license [1].

The license itself carries terms. 10 CFR 52.167(b) provides that a manufacturing license specifies terms and conditions, technical specifications, site parameters, design characteristics, and interface requirements [3]. 10 CFR 52.167(c)(2) reaches into the commercial layer: the holder is required to write NRC-approved shipping requirements into the transport contract [3]. That provision is unusual and worth noticing. The rule anticipates that the custody chain runs through an agreement with a carrier, and it places a regulatory requirement inside a private contract. It is one of the few points in the framework where a document rather than an inspection is the control.

Two further provisions bear on the fleet case. Under 10 CFR 52.171(a)(2) a design modification imposed by the Commission will be applied to all reactors manufactured under the license, including those that have already been transported and sited [1]. That is a configuration-management obligation reaching units the manufacturer no longer holds. 10 CFR 52.173 runs a manufacturing license for five to fifteen years and provides that manufacture may not be initiated less than three years before expiry [1]. On the historical record, the NRC historian writes that the Offshore Power Systems production facility in Jacksonville needed an NRC manufacturing license, that the NRC did not issue a license until 1982, and that Westinghouse formally abandoned the enterprise in 1984 [38]. This paper does not characterize how many manufacturing licenses have been issued under Subpart F. Our survey of which regulations apply to a microreactor places Subpart F among the available pathways.

3. What the existing verification construct actually does

The acronym is used loosely, so it is worth stating what the machinery is. Inspections, tests, analyses, and acceptance criteria are commitments carried in a license application: an activity to be performed, and a criterion the result has to meet. The NRC's own description explains that they are sourced either from a certified design or written for a specific site, that the agency reviews closure notifications, and that inspection manual chapter 2503 is the vehicle through which the associated inspections are carried out [5]. A point commonly gotten wrong deserves emphasis here: these criteria are required in a manufacturing license application by 10 CFR 52.158, not in a combined license alone [1]. The instrument for verifying off-site construction already sits inside the manufacturing pathway.

10 CFR 52.99 supplies the reporting machinery. Under paragraph (c)(1) the licensee submits closure notifications as acceptance criteria are met. Under paragraph (c)(3) the licensee notifies the Commission of uncompleted criteria no later than 225 days before the scheduled date for initial loading of fuel. Paragraph (b) provides that the licensee may proceed at its own risk with construction activity, which places the schedule consequence of a disputed finding on the licensee rather than on the regulator [4]. The corresponding provision governing issuance of combined licenses sits at 10 CFR 52.97 [6].

The most interesting provision for the purposes of this paper is the post-closure notification at 10 CFR 52.99(c)(2) [4]. That duty was established by a final rule published in the Federal Register on August 28, 2012 at 77 FR 51880, which set out a requirement to report information that materially alters a previously submitted closure notification [9]. The acknowledgment embedded in that rulemaking is worth naming: a closed acceptance criterion can be invalidated by information that arrives afterwards. That is not a defect in the instrument, it is a configuration-management property. A verification record that cannot be superseded is a record that will eventually be wrong, and any construct proposed in place of this one has to inherit the property rather than drop it.

The construct is also younger than it looks, which matters when judging an alternative against it. The Government Accountability Office reported in 2007 that the NRC was continuing to develop several components of the process, such as the final closeout review for ensuring all criteria are met, and had just begun staffing the construction inspection program [8]. Measuring a records-based alternative against an idealised version of a construct that took years to mature would be unfair to the alternative. Our paper on evidentiary standards for machine-generated reactor records takes up the separate question of what makes such a record usable as evidence at all.

4. How the regulator reaches a factory today

Between the rule text and the factory floor sits the vendor inspection program. The NRC describes it directly: vendor inspections are conducted at vendor shops principally to examine whether the vendor has been complying with Appendix B to Title 10, Part 50, as required by procurement contracts with licensees [10]. The legal shape of that sentence matters. The quality requirement travels to the vendor through a procurement contract rather than through a license, because the vendor is not a licensee. The Appendix B criteria themselves apply quality assurance to design, fabrication, construction, and testing [14], so the substantive coverage of the factory phase is present; what differs is the instrument through which it is enforced.

The enforcement instruments follow from that shape. The NRC states that notices of nonconformance or notices of violation are issued to vendors for failures to meet quality commitments or the requirements of 10 CFR Part 21 [10]. Part 21 places a duty on suppliers of basic components to notify the Commission immediately of defects that could create a substantial safety hazard [13]. And the agency states the allocation of responsibility plainly: licensees are ultimately responsible for vendor oversight [10]. In the factory-fabricated case that allocation deserves examination, because the party held responsible for overseeing a manufacture may be a site licensee that was not yet a licensee while the manufacture was under way.

Two dated facts belong in the record, stated without insinuation. Take them in date order. The NRC Office of the Inspector General audited the process for inspections, tests, analyses, and acceptance criteria in 2012 (a 2012 finding of the NRC Office of the Inspector General), and one finding in that audit was titled to the effect that a formal strategy for inspection of components at modular assembly facilities would strengthen the inspection program [7]. The background to that finding records that vendor inspections are performed as part of the inspection effort in particular because a key characteristic of the then-current approach to new reactor construction is the use of modular assemblies, constructed offsite and shipped to the construction site for installation [7].

The second dated fact concerns the public record of results. The NRC's published vendor inspection program plan page lists revision 30, dated July 2024, describes the plan as updated every six months, and records annual self-assessments through fiscal year 2024 [11]. The agency page collecting vendor inspection findings related to acceptance criteria, which posts summary letters covering vendors supporting the Vogtle and Summer projects, carries a most recent posted letter dated October 12, 2018 [12]. This paper draws no conclusion from either fact about the diligence of the agency or of any vendor. Both are stated because omitting them would be selecting the evidence. What they establish is narrower: the public, per-item record of factory inspection findings available to a party outside the transaction is thin, and it is thin at the point where the factory-fabricated premise puts the most weight.

5. What the proposed microreactor framework would do, and what it sets aside

Proposed 10 CFR Part 57 (a proposed rule published in the Federal Register on May 1, 2026, with the comment period closed on June 15, 2026; not final, and no developer is licensed under it) would build its own manufacturing pathway [19]. Its Subpart D is titled Manufacturing Licenses, and the proposed scope provision at 57.145 covers manufacture at a manufacturing facility, fuel loading into manufactured reactors there, and transportation of manufactured reactors. Across its 139 pages manufacturing license appears 183 times and manufactured reactor 147 times.

Several provisions of proposed 10 CFR Part 57 (a proposed rule published in the Federal Register on May 1, 2026, with the comment period closed on June 15, 2026; not final, and no developer is licensed under it) carry verification content [19]. Proposed 57.160(d)(1) would require a description of the codes and standards used in procurement, fabrication, and assembly. Proposed 57.160(d)(3) would require "a description of the tests and inspections to be performed during the manufacturing and fabrication process, including components, as well as an assembled manufactured reactor." Proposed 57.160(e)(1) would require information on shipping preparation, the conduct of shipping, and verification on receipt. Proposed 57.197(f) would address required receipt inspections and verification that interface requirements between the reactor and the balance of the plant have been met.

Against that, ITAAC appears four times in the 139 pages of proposed 10 CFR Part 57 (a proposed rule published in the Federal Register on May 1, 2026, with the comment period closed on June 15, 2026; not final, and no developer is licensed under it). The NRC states its reasoning: "The NRC didn't pursue amending part 52 or implementing a combined license approach in this proposed rule because the requirements for inspections, tests, analyses, and acceptance criteria (ITAAC) were designed for light water reactors (LWRs) (required by the Atomic Energy Act of 1954, as amended (AEA)) and the associated hearing on ITAAC closure could extend the licensing timeline." [19] Both reasons are legitimate. Acceptance criteria built around light water systems do not transfer cleanly to other technologies.

The agency also invites challenge to its own premise. Question Q12-1 of proposed 10 CFR Part 57 (a proposed rule published in the Federal Register on May 1, 2026, with the comment period closed on June 15, 2026; not final, and no developer is licensed under it) asks whether the conclusion that the existing pathways would impose unnecessary burden and extend review timelines for microreactors is accurate and sufficiently supported, and Q12-2 asks what alternatives, "e.g., targeted modifications to part 52, streamlined ITAAC constructs, or scoped use of part 53 elements", the NRC should evaluate [19]. That second question is the reason this paper exists. Setting an instrument aside because it was built for a different technology and carries a hearing is a reason to replace its functions, not a finding that its functions are unnecessary. Our explainer on the proposed microreactor framework covers the operating-model provisions in the same proposal.

6. Transport as an evidence gap

Between the factory and the site the unit is in transport, and transport is governed by 10 CFR Part 71 [20]. The external radiation standard at 10 CFR 71.47(b)(3) sets a limit measured at two meters from the vehicle for exclusive-use shipments [21]. For a fueled microreactor that limit is a live engineering constraint rather than a formality. A Pacific Northwest National Laboratory report prepared for the NRC states in its abstract that microreactors may be challenged to meet the current 10 mrem/hr limit at 2 meters from the vehicle in 10 CFR 71.47(b) [23].

The NRC's proposed rule on package certification requirements (a proposed rule published in the Federal Register on July 27, 2026; a proposed rule that is not final) addresses the point directly. That proposal states that shipment of a fueled microreactor on accelerated timelines with "less than one-year of cooling" means "external radiation levels during transport could exceed the 0.1 millisievert per hour (mSv/h) (10 millirem per hour (mrem/h)) at 2 meters (m) from the vehicle radiation level limit currently specified in Sec. 71.47(b)(3)" [22]. It proposes an alternative radiation standard for certain exclusive-use Type B shipments and risk-informed alternatives under 10 CFR 71.41 [22].

The supporting technical record is being assembled. The Pacific Northwest National Laboratory dose assessment is the technical basis for the transport dose question [23], and the companion prototype microreactor transportation safety program report records that designs often assume the unit can be transported containing either unirradiated or irradiated fuel [24]. Argonne National Laboratory has published a microreactor core transportation cask model description supporting a criticality safety validation basis assessment [25], and Sandia National Laboratories has published a qualification framework for the safe transportation of microreactors [26].

The verification point is separate from the dose point. Transport is a custody interval during which the unit is outside the manufacturing facility's quality assurance boundary and is not yet inside the site's. The framework in force reaches that interval through the shipping requirements 10 CFR 52.167(c)(2) obliges the license holder to write into the transport contract [3]. Under the proposal, 57.160(e)(1) of proposed 10 CFR Part 57 (a proposed rule published in the Federal Register on May 1, 2026, with the comment period closed on June 15, 2026; not final, and no developer is licensed under it) would require information on "the procedures governing the preparation of the manufactured reactor for shipping to the site where it is to be operated, the conduct of shipping, and the verification of the condition of the shipped items upon receipt at the site" [19]. That provision names the verification without naming what it rests on. A receipt inspection can establish that a sealed unit arrived with its seals intact. It cannot, by itself, establish what was inside the seals when they were applied, and that is a records question rather than an inspection question.

7. What a records-based construct would have to provide

If the existing construct is set aside for a factory-built reactor, the functions it performs do not disappear. Six are separable because the rule text separates them: a criterion fixed before the work and reviewed in the application [1]; a determination made by an identified party and reported [4]; a result a third party can examine without repeating the work [5]; a commitment binding to the reactor manufactured under the license rather than to a design in the abstract [1]; a finding that can be superseded when later information invalidates it, as the post-closure duty and the fleet-modification provision each express [4][9]; and a record that reaches a party who was not present.

One feature of the proposal sharpens the fourth. Proposed 57.197 of proposed 10 CFR Part 57 (a proposed rule published in the Federal Register on May 1, 2026, with the comment period closed on June 15, 2026; not final, and no developer is licensed under it) would include requirements applying to portions of a manufactured reactor, in recognition that activities under a manufacturing license may occur at different fabrication facilities [19]. A single unit's provenance can therefore run through more than one plant, an argument for binding the record to the unit rather than the facility. The closest regulatory slots such a record could occupy are proposed 57.160(e)(1) and proposed 57.197(f), both of which describe a verification without specifying its evidentiary basis. Table 1 sets each function against what the existing construct supplies and what a substitute would need. The center column is drawn from the cited rule text; the right column is RankShield Energy analysis, offered for disagreement.

Table 1. Verification functions performed in an off-site build under the framework in force, and what a records-based construct would have to supply for each. The center column reports the cited rule text and the agency's description of it. The right column is RankShield Energy analysis. This table is not a regulatory position, it has not been reviewed or accepted by the NRC, and nothing in it is required, endorsed, or approved by any agency.
Verification function What the existing construct supplies What a records-based construct would have to supply
Criterion fixed before the work Acceptance criteria are contained in the license application and reviewed there, so the criterion precedes the activity that tests it (10 CFR 52.158) A criterion committed and published before fabrication begins, bound so that a later reading of the record cannot silently alter what was promised
Identified determining party The licensee performs the inspection, test, or analysis, determines that the criterion is met, and notifies the Commission (10 CFR 52.99(c)(1)) A named accountable party for each determination, distinguishable in the record from the party that performed the underlying work
Checkable without repetition A closure notification is a document the agency reviews rather than a test it repeats, with inspection sampled separately A record whose integrity a reviewer can check computationally, without re-performing the fabrication test and without access to the factory
Binding to the physical unit Criteria in a manufacturing license application attach to the reactor manufactured under that license (10 CFR 52.158) An identifier bound to the individual unit and carried with it, so that a record cannot be transferred between units of the same design
Revision when later information arrives The post-closure notification duty (10 CFR 52.99(c)(2)) and the fleet-modification provision reaching sited units (10 CFR 52.171(a)(2)) An append-only history in which a superseding finding is added and the earlier record remains visible, rather than an editable record of current state
Availability to an absent party Notifications are submitted to the Commission and enter the public docket A proof a party with no relationship to the manufacturer can check offline, at a time of its choosing, without the manufacturer's cooperation

Mechanisms in the standards record map onto those requirements. They are candidates, not anything the agency has adopted or referenced. IETF RFC 9334 supplies a vocabulary of attestation roles: who produces evidence, who appraises it, and who relies on the result [34]. IETF RFC 9943 supplies an append-only model in which statements about an artifact are registered and can be superseded but not silently removed [35]. IETF RFC 9942 supplies a receipt a verifier can check without contacting the party that issued it [36]. NIST FIPS 204 supplies a signature standard [37].

Two limits belong with it. Nothing in 10 CFR Part 21 [13], Appendix B to 10 CFR Part 50 [14], 10 CFR Part 52 [1], or the proposed microreactor framework [19] references machine-verifiable attestation, and this paper does not suggest that any of them implies it. The exposure is one the agency already names: its material on counterfeit, fraudulent, and suspect items states that vendors, suppliers and nuclear power plants must verify the quality of items destined for safety-related functions, and that verification includes extensive inspections combined with rigorous performance testing [27]. NIST SP 800-161r1 frames the same exposure for systems whose components may be counterfeit or poorly manufactured [28]. Our reference architecture for independent verification covers the operating-phase version.

8. Applying this to RankShield Energy

The standard this paper follows requires it to apply its own analysis to RankShield Energy. The accurate statement is short. RankShield Energy does not operate a manufacturing facility. It has not applied for a manufacturing license under 10 CFR Part 52 Subpart F [1], nor under the framework the NRC has proposed for microreactors. It has not qualified a supply chain against Appendix B to 10 CFR Part 50 [14]. It has never shipped a reactor. It is a pre-applicant in early regulatory interaction with the NRC, holds no NRC license, permit, or design approval, and nothing in the design has been demonstrated to or accepted by the agency.

Our experience is in attestation and verification engineering and in navigating pre-application, not in nuclear manufacturing, and that distinction governs how section 7 should be read. The decomposition there is an architecture argument: it asks what a verification record has to do and answers in terms of properties a record can be made to have. It is not a manufacturing argument. It does not address whether a factory can hold a tolerance, how a welding procedure is qualified, what a receiving inspection can physically detect, or how many units a supply chain can deliver before a quality escape becomes probable. Those are the questions a manufacturer would be answering, and we are not answering them.

There is also an incentive problem, and it belongs in the paper rather than in a reader's margin. A developer whose competence is in records has an obvious interest in a regulatory construct that runs on records. That interest does not make the argument wrong, but it means the argument should not be weighed by who is making it. The test we would ask a reviewer to apply is whether the six functions in section 7 are correctly decomposed from the cited rule text, and whether any function has been dropped. If a function is missing, a construct built on the list is incomplete regardless of who proposed it.

Two things we do not know bound the argument. We do not know what evidentiary weight a cryptographic manufacturing record would carry in an NRC proceeding; the question is untested. And we do not know which streamlined construct the agency will adopt after comment, if it adopts one, because Q12-2 of proposed 10 CFR Part 57 (a proposed rule published in the Federal Register on May 1, 2026, with the comment period closed on June 15, 2026; not final, and no developer is licensed under it) is an invitation rather than a signal [19]. Staff analysis has canvassed adjacent questions without settling them: SECY-20-0093 on policy and licensing considerations related to micro-reactors [17] and SECY-25-0052 on nth-of-a-kind licensing and deployment considerations (a staff paper, which is staff analysis and not a Commission position) [18]. Our guide to evaluating a microreactor vendor sets out questions a buyer can ask, and these are ones we would expect to be asked of us.

Frequently asked questions

Who actually inspects a reactor while it is being built in a factory?

Under the framework in force, a manufacturing license application has to contain inspections, tests, analyses, and acceptance criteria sufficient to assure that the reactor has been manufactured in conformity with the manufacturing license, and 10 CFR 52.157 requires the applicant to describe its proposed means of assuring that manufacturing conforms to the design and to give the NRC enough to prepare acceptance and inspection requirements. Alongside that, the NRC conducts sampled inspections at vendor shops to examine compliance with Appendix B to 10 CFR Part 50, and it states that licensees are ultimately responsible for vendor oversight. The vendor is not a licensee, so the quality requirement reaches it through a procurement contract rather than through a license.

Does the proposed microreactor rule remove the ITAAC construct?

No, and it should not be overstated. The instrument in question is proposed 10 CFR Part 57 (a proposed rule published in the Federal Register on May 1, 2026, with the comment period closed on June 15, 2026; not final, and no developer is licensed under it). It does not amend 10 CFR Part 52 and it abolishes nothing. It proposes a separate framework whose manufacturing subpart does not use that construct, and the NRC explains that it did not pursue a combined license approach because those requirements were designed for light water reactors and the associated closure hearing could extend the licensing timeline. The agency invites comment on streamlined constructs in its question Q12-2, so the matter is open rather than settled.

Are inspections, tests, analyses, and acceptance criteria a combined-license feature?

No. 10 CFR 52.158 requires a manufacturing license application to contain inspections, tests, analyses, and acceptance criteria sufficient to assure that the reactor has been manufactured in conformity with the manufacturing license. This is commonly misstated. The reporting machinery at 10 CFR 52.99, which includes closure notifications, the post-closure notification duty, and the 225-day notification for uncompleted criteria, is what most readers picture when they hear the acronym, and that machinery is written around inspection during construction.

What happens to verification while the unit is in transport?

Transport is governed by 10 CFR Part 71, and the external radiation standard at 10 CFR 71.47(b)(3) is the provision a fueled microreactor shipment is most likely to press against. A Pacific Northwest National Laboratory assessment prepared for the NRC states that microreactors may be challenged to meet that limit. For verification specifically, transport is a custody interval in which the unit sits outside the manufacturing facility's quality assurance boundary and is not yet inside the site's. Proposed provisions of proposed 10 CFR Part 57 (a proposed rule published in the Federal Register on May 1, 2026, with the comment period closed on June 15, 2026; not final, and no developer is licensed under it) would require verification of the condition of shipped items on receipt at the site without specifying what that verification rests on.

What would change the analysis in this paper?

A final microreactor licensing rule, or withdrawal or material amendment of the proposal. A published agency position on what a streamlined construct for verifying off-site manufacture would consist of. A final rule following the NRC's proposed rule on package certification requirements (a proposed rule published in the Federal Register on July 27, 2026; a proposed rule that is not final). New national-laboratory results on microreactor transport that change the dose or criticality picture. Or any agency statement addressing the evidentiary status of machine-generated manufacturing records, on which the cited record is silent. Any of those would move the decomposition in section 7, and the paper is versioned so that movement can be recorded.

Sources

  1. U.S. National Archives, eCFR. 10 CFR Part 52 Subpart F, Manufacturing Licenses (sections 52.151, 52.153, 52.157, 52.158, 52.171, 52.173). Current edition, accessed September 2026
  2. U.S. Government Publishing Office. 10 CFR 52.151, Scope of subpart. CFR 2025, title 10, volume 2
  3. U.S. Government Publishing Office. 10 CFR 52.167, Issuance of manufacturing license. CFR 2025, title 10, volume 2
  4. U.S. Government Publishing Office. 10 CFR 52.99, Inspection during construction; schedules and notifications. CFR 2025, title 10, volume 2
  5. U.S. Nuclear Regulatory Commission. Inspections, Tests, Analyses, and Acceptance Criteria (ITAAC). Page last reviewed August 27, 2026
  6. U.S. National Archives, eCFR. 10 CFR 52.97, Issuance of combined licenses. Last amended 91 FR 20067, April 15, 2026
  7. U.S. Nuclear Regulatory Commission, Office of the Inspector General. Audit of NRC's Inspections, Tests, Analyses, and Acceptance Criteria (ITAAC) Process, OIG-12-A-16 (an audit finding dated July 12, 2012)
  8. U.S. Government Accountability Office. GAO-07-1129. September 2007
  9. U.S. Nuclear Regulatory Commission. Requirements for Maintenance of Inspections, Tests, Analyses, and Acceptance Criteria. Final rule, 77 FR 51880, August 28, 2012. The source credit for 10 CFR 52.99 reads 77 FR 51892, August 28, 2012
  10. U.S. Nuclear Regulatory Commission. Vendor Quality Assurance (QA) Inspections. Page last reviewed August 27, 2026
  11. U.S. Nuclear Regulatory Commission. Vendor Inspection Program (VIP) Plan (program page; revision 30, July 2024). Page last reviewed August 27, 2026
  12. U.S. Nuclear Regulatory Commission. ITAAC Related Vendor Inspection Findings. Page last reviewed August 27, 2026
  13. U.S. Government Publishing Office. 10 CFR Part 21, Reporting of Defects and Noncompliance. CFR 2025, title 10, volume 1
  14. U.S. Government Publishing Office. Appendix B to 10 CFR Part 50, Quality Assurance Criteria for Nuclear Power Plants and Fuel Reprocessing Plants. CFR 2025, title 10, volume 1
  15. U.S. Nuclear Regulatory Commission. Microreactors: Regulatory Activities. Page last reviewed August 11, 2026
  16. U.S. Nuclear Regulatory Commission. SECY-24-0008, Micro-Reactor Licensing and Deployment Considerations: Fuel Loading and Operational Testing at a Factory, ADAMS ML23207A252 (staff paper, staff analysis and not a Commission position). Released February 8, 2024
  17. U.S. Nuclear Regulatory Commission. SECY-20-0093, Policy and Licensing Considerations Related to Micro-Reactors, ADAMS ML20254A363 (staff paper, staff analysis and not a Commission position). Released October 23, 2020
  18. U.S. Nuclear Regulatory Commission. SECY-25-0052, Nth-of-a-Kind Microreactor Licensing and Deployment Considerations, ADAMS ML24309A266 (staff paper, staff analysis and not a Commission position). Released July 3, 2025
  19. U.S. Nuclear Regulatory Commission. Licensing Requirements for Microreactors and Other Reactors With Comparable Risk Profiles (proposed 10 CFR Part 57). Federal Register, May 1, 2026 (91 FR 23628), Docket NRC-2025-0379; proposed rule, comment period closed June 15, 2026, not final
  20. U.S. National Archives, eCFR. 10 CFR Part 71, Packaging and Transportation of Radioactive Material. Current edition, accessed September 2026
  21. U.S. National Archives, eCFR. 10 CFR 71.47, External radiation standards for all packages. Current edition, accessed September 2026
  22. U.S. Nuclear Regulatory Commission. Modernizing Package Certification Requirements. Federal Register, July 27, 2026 (91 FR 46869), Docket NRC-2025-1667; proposed rule, not final
  23. Pacific Northwest National Laboratory for the U.S. Nuclear Regulatory Commission. Microreactor Incident-Free Transportation Radiation Dose Assessment, PNNL-38760 (contractor report). December 31, 2025
  24. Pacific Northwest National Laboratory. Final Prototype Microreactor Transportation Safety Program, PNNL-38272 (laboratory report). September 22, 2025
  25. Argonne National Laboratory. Microreactor Core Transportation Cask Model Description for Criticality Safety Validation Basis Assessment (Rev. 2), ANL/NSE-25/97-Rev2 (laboratory report). May 29, 2026
  26. Sandia National Laboratories. A qualification framework for the safe transportation of microreactors, SAND2025-07256C (laboratory conference paper). June 2025
  27. U.S. Nuclear Regulatory Commission. Counterfeit, Fraudulent, and Suspect Items. Page last reviewed August 27, 2026
  28. National Institute of Standards and Technology. Cybersecurity Supply Chain Risk Management Practices for Systems and Organizations, SP 800-161r1. May 2022, updated November 1, 2024
  29. Abou-Jaoude et al., Idaho National Laboratory and Munro and Associates. Assessment of Factory Fabrication Considerations for Nuclear Microreactors. Nuclear Technology, June 12, 2023
  30. Oak Ridge National Laboratory. Mid-Year Progress Update on ORNL Support for Developing the Guidance for Microreactor Manufacturing Licenses, ORNL/LTR-2022/405 (contractor report). April 2022
  31. Idaho National Laboratory for the U.S. Department of Energy. A Microreactor Program Plan for The Department of Energy, INL/EXT-20-58919 Rev. 4. May 2025
  32. Brookhaven National Laboratory for the U.S. Nuclear Regulatory Commission. Assessment of modular construction for safety-related structures at advanced nuclear power plants, NUREG/CR-6486 (contractor report). March 1997
  33. Idaho National Laboratory. Regulatory and Licensing Strategy for Microreactor Technology, INL/EXT-18-51111-Rev000 (laboratory report). August 2018
  34. Internet Engineering Task Force. RFC 9334, Remote ATtestation procedureS (RATS) Architecture (Informational). January 2023
  35. Internet Engineering Task Force. RFC 9943, An Architecture for Trustworthy and Transparent Digital Supply Chains (Standards Track). June 2026
  36. Internet Engineering Task Force. RFC 9942, CBOR Object Signing and Encryption (COSE) Receipts (Standards Track). June 2026
  37. National Institute of Standards and Technology. FIPS 204, Module-Lattice-Based Digital Signature Standard. August 13, 2024
  38. Wellock, T., U.S. Nuclear Regulatory Commission historian. Floating Nuclear Power Plants: Waves of Uncertainty (Part II). Page last reviewed August 11, 2026
  39. U.S. Nuclear Regulatory Commission. Modernizing Reactor Licensing, Safety Oversight, and Siting Practices. Federal Register, July 16, 2026 (91 FR 44560); proposed rule, not final

Open questions

Questions this paper does not resolve, including those we cannot answer from the current record.

  1. OQ-1. Which streamlined construct the agency adopts. What construct, if any, the NRC adopts after comment in place of inspections, tests, analyses, and acceptance criteria for a factory-built reactor, given that Q12-2 of proposed 10 CFR Part 57 (a proposed rule published in the Federal Register on May 1, 2026, with the comment period closed on June 15, 2026; not final, and no developer is licensed under it) invites comment on the question [19]. Staff analysis has addressed factory fuel loading and operational testing at a factory in SECY-24-0008 (a staff paper, which is staff analysis and not a Commission position) [16] without settling the verification construct. Unresolved because a comment period closing is not a rulemaking outcome. Resolver: the NRC, through rulemaking.
  2. OQ-2. Whether a factory quality assurance program can substitute for an independent determination. Whether a program meeting the Appendix B criteria [14], enforced through procurement contracts and reached by sampled vendor inspection [10], can stand in for a per-unit determination reported to the regulator, and under what conditions. Unresolved because the cited record describes the two mechanisms separately rather than treating either as a substitute for the other. Resolver: the NRC, through rulemaking and review practice.
  3. OQ-3. Who bears the inspection cost at nth-of-a-kind rates. How the cost of factory inspection is allocated when units are produced in series rather than singly, given that staff analysis of nth-of-a-kind microreactor licensing and deployment considerations canvasses the deployment question (a staff paper, which is staff analysis and not a Commission position) [18] and that the agency's microreactor regulatory activities page records the statutory direction to develop oversight and inspection strategies [15]. Resolver: the NRC, with congressional appropriators.
  4. OQ-4. Discharging the fleet-modification obligation across sited units. How the obligation at 10 CFR 52.171(a)(2), under which a Commission-imposed design modification is applied to all reactors manufactured under the license including those already transported and sited [1], is discharged when the units are numerous, remote, and held by different licensees. Unresolved because the provision states the obligation without describing a mechanism at fleet scale. Resolver: the NRC and manufacturing license holders, on specific dockets.
  5. OQ-5. Whether a receipt inspection at a thinly staffed site can be meaningful. What a receipt inspection under proposed 57.160(e)(1) and proposed 57.197(f) of proposed 10 CFR Part 57 (a proposed rule published in the Federal Register on May 1, 2026, with the comment period closed on June 15, 2026; not final, and no developer is licensed under it) can establish at a site whose staff have limited reactor construction experience [19], given that the corresponding provision in the framework in force reaches the shipment through a transport contract rather than through a site inspection [3]. Resolver: the NRC, through guidance and review practice.
  6. OQ-6. Whether transport custody belongs to the manufacturer's boundary or the site's. Whether the transport interval should be treated as part of the manufacturing licensee's quality assurance boundary or the receiving site's, given that Part 71 governs the package [20], that laboratory work assumes the unit may travel with unirradiated or irradiated fuel [24], and that cask and qualification work is still being published [25][26]. The question is not confined to domestic movement: Proposed 10 CFR Part 57 (a proposed rule published in the Federal Register on May 1, 2026, with the comment period closed on June 15, 2026; not final, and no developer is licensed under it) would at 57.197(e) permit removal from the place of manufacture for export under 10 CFR Part 110, which the rule notes differs from 10 CFR 52.153 [19]. Resolver: the NRC, through rulemaking.
  7. OQ-7. Whether the public per-item record of factory findings is intended to grow. Whether the public posting of vendor inspection findings related to acceptance criteria [12], alongside the published program plan and its self-assessment cadence [11], is expected to expand for factory-fabricated units, and whether a party outside the transaction is intended to be able to rely on it. Unresolved because the cited pages describe a program rather than a disclosure policy. Resolver: the NRC.
  8. OQ-8. We cannot answer this one. What evidentiary weight a cryptographic manufacturing record would carry in an NRC proceeding. The mechanisms exist as published standards [35][36], and the supply-chain exposure they address is recognized in federal guidance [28], but the question is untested: we have found nothing in the cited record that establishes how such a record would be weighed, and we are not in a position to assert an answer. Resolver: the NRC and, ultimately, an adjudicatory record.

This paper reflects the state of the cited record as of its revision date. Regulatory proposals, national-laboratory results, and standards referenced here are subject to change. Section references to proposed rules should be re-checked against the current docket before use.

Related

This paper reflects the state of the NRC manufacturing, construction-inspection, vendor inspection, and transport record as of September 2026. Proposed requirements, including proposed 10 CFR Part 57 (a proposed rule published in the Federal Register on May 1, 2026, with the comment period closed on June 15, 2026; not final, and no developer is licensed under it), may change before any final rule issues. Re-check the docket before relying on any section reference here.

About this article. RankShield Energy is a pre-applicant engaged in early regulatory interaction with the U.S. Nuclear Regulatory Commission (NRC). Nothing here should be read as a representation that any RankShield Energy design, product, or facility is NRC-approved, licensed, or certified, or that any safety, performance, or operational characteristic has been demonstrated or accepted by the NRC. Descriptions of reactor and system behavior reflect design intent and are subject to analysis, testing, and regulatory review. This article is for general educational purposes and is not engineering, legal, regulatory, or investment advice.

A note on how we write about our own reactor

HELIX is in pre-application development. Where this article touches our design, every figure is a design target and every physics result is unqualified screening, labeled as such. We cite authoritative sources (NRC, DOE, IAEA, national laboratories) and never invent statistics.

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