# 2026-19217: NRC Drafts Rules for Weirder Nuclear Reactor Materials

2026-19217, Draft Interim Staff Guidance: Material Compatibility for Non-Light Water-Reactors, is a Federal Register notice from Nuclear Regulatory Commission published 2026-09-21, effective Submit comments by November 5, 2026. Comments received after this date will be considered if it is practical to do so, but the Commission is able to ensure consideration only for comments received on or before this date. (as of 2026-09-28).

- Canonical: https://policyrisk.com/federal-register/2026-19217
- As of: 2026-09-28
- Plain-text twin of the page above; the HTML and this file carry the same facts.

## Facts
- Document number: 2026-19217
- Title: Draft Interim Staff Guidance: Material Compatibility for Non-Light Water-Reactors
- Type: Notice
- Agencies: Nuclear Regulatory Commission
- Citation: 91 FR 59813
- Published: 2026-09-21
- Effective: Submit comments by November 5, 2026. Comments received after this date will be considered if it is practical to do so, but the Commission is able to ensure consideration only for comments received on or before this date.
- Comments close: 2026-11-05
- Significant: no
- Touches household money: no
- Regulation identifier numbers: none
- Last updated: 2026-09-28

## In one line

NRC Drafts Rules for Weirder Nuclear Reactor Materials

## Summary

The Nuclear Regulatory Commission (NRC) is updating its guidance to help review new types of nuclear reactors that don’t use regular water, called non-light water reactors. This update adds important info about materials and safety rules to make sure these reactors are safe and reliable. If you’re involved in designing or regulating these reactors, now’s the time to share your thoughts before November 5, 2026!

## Abstract

The U.S. Nuclear Regulatory Commission (NRC) is soliciting public comment on its draft Interim Staff Guidance (ISG), "Material Compatibility for non-Light-Water Reactors, DANU-ISG-2023-01, Revision 1." The purpose of this draft ISG is to assist the NRC staff in reviewing certain applications for non-light water reactor designs, including power and non-power reactors. This ISG has been updated to include an appendix to describe information the NRC staff generally have used to perform the review of materials of construction and passive structures, systems, and components (SSCs) performance for non- light water reactors (non-LWRs), as well as limited updates to technical information in the main body. It has also been updated to make it applicable to certain additional NRC regulations.

## Effects PRIA read

No economic effects identified for this document.

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## Sources
- [2026-19217 on federalregister.gov](https://www.federalregister.gov/documents/2026/09/21/2026-19217/draft-interim-staff-guidance-material-compatibility-for-non-light-water-reactors)
- [2026-19217 as published (PDF)](https://www.govinfo.gov/content/pkg/FR-2026-09-21/pdf/2026-19217.pdf)

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- [All Federal Register documents](https://policyrisk.com/federal-register)

Source: PRIA, https://policyrisk.com/federal-register/2026-19217 (as of 2026-09-28).