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Spotlight
Kaleidos
Project Overview
The U.S. Nuclear Regulatory Commission (NRC) is currently engaged in pre-application activities with Radiant Industries, Inc. (Radiant), starting in October 2022. Radiant is an El Segundo, CA company developing its Kaleidos design, a transportable micro-reactor designed to generate 3MWth and approximately 1MWe. The Kaleidos micro-reactor is a high-temperature gas-cooled reactor (HTGR) using TRISO fuel, helium gas coolant, and prismatic graphite blocks. Each micro-reactor will be fully contained in a single shipping container.
For more information, please see the Radiant pre-application documents (NRC Docket 99902106).
To subscribe to the Radiant Kaleidos email service, select Radiant Kaleidos from the Advanced Reactors list after entering your email into the GovDelivery system.
Pre-Application Activities
| Product | Type | Reference | Status |
| Radiant Kaleidos Micro-reactor Pre-application Regulatory Engagement Plan – October 2023 | Regulatory Engagement Plan | ML23286A328 | No review requested |
| 10 CFR 70 Gap Analysis | White Paper | ML24115A321 | ML24262A066 |
| 10 CFR Part 50 and 52 Gap Analysis | White Paper | ML24250A206 | ML25013A338 |
| 10 CFR Part 100 Gap Analysis | White Paper | ML24275A261 | ML25017A130 |
| 10 CFR Part 51 Gap Analysis | White Paper | ML24298A242 | ML25023A086 |
| 10 CFR Part 55 Gap Analysis | White Paper | ML25188A228 | Under Review |
| Kaleidos Fleet Operator Training White Paper | White Paper | Non-public proprietary | Under Review |
| Kaleidos Factory Fueling Operations | White Paper | ML25226A241 | No Review Requested |
| Kaleidos Development Unit Commissioning Plan | White Paper | Non-public Proprietary | Under Review |
| Radiant Regulatory Engagement Plan, Revision 1 | Regulatory Engagement Plan | Non-public Proprietary | Superseded by Revision 2 |
| Radiant Regulatory Engagement Plan, Revision 2 | Regulatory Engagement Plan | ML26138A108 | No Review Requested |
10 CFR Part 70 Licensing Activities
| Product | Type | Reference | Status |
| Radiant – R-50 Special Nuclear Materials License Application | Application | ML26058A374 ML26074A001 ML26107A169 ML26110A219 | Received; Under Review |
| Acceptance of Radiant Nuclear R-50 Special Nuclear Material License Application (with observations) | NRC Letter | ML26112A019 | Issued |
| Radiant - Response to Observations in NRC Acceptance Letter May 1, 2026, to R-50 Special Nuclear Materials License Application | Applicant Letter | ML26165A001 | Received |
| Request For Additional Information for Environmental Review of the Radiant R-50 Special Nuclear Material License Application | NRC RAI Letter | ML26169A217 | Issued |
| Radiant Industries, Inc., Environmental RAI Response to NRC letter dated June 24, 2026, to R-50 Special Nuclear Materials License Application | Applicant Letter | ML26181A042 | Received |
| Radiant R-50 Special Nuclear Material License Application - DRAFT Historic and Cultural Evaluation for Public Review | NRC Draft Report | ML26188A258 | Available for public review |
| Request for Additional Information Set 1 – Review of the Radiant Nuclear R-50 Special Nuclear Material License Application | NRC RAI Letter | ML26190A174 | Issued |
| Request for Additional Information Set 2 – Review of the Radiant Nuclear R-50 Special Nuclear Material License Application | NRC RAI Letter | ML26216A291 | Issued |
Contacts
| Contacts for the Kaleidos Pre-Application Review | |
|---|---|
| Lead Project Manager | Kevin Roche |
| Contact a Public Affairs Officer | |
Page Last Reviewed/Updated Tuesday, September 08, 2026
Page Last Reviewed/Updated Tuesday, September 08, 2026