{"abstract":"The U.S. Nuclear Regulatory Commission (NRC) is issuing two related Regulatory Guides (RGs), namely RG 1.59, Revision 3, \"Design- Basis Floods for Nuclear Power Plants,\" and RG 1.256, Revision 0, \"Guidance for Assessment of Flooding Hazards due to Water Control Structure Failures and Incidents.\" RG 1.59 provides guidance for applicants for new nuclear power plants on acceptable methods for evaluating design-basis floods and RG 1.256 provides guidance for applicants on methods for evaluating flooding hazards due to failure or other incidents at man-made water control structures including, but not limited to, dams and levees.","action":"Final guide, issuance.","agencies":[{"raw_name":"NUCLEAR REGULATORY COMMISSION","name":"Nuclear Regulatory Commission","id":383,"url":"https://www.federalregister.gov/agencies/nuclear-regulatory-commission","json_url":"https://www.federalregister.gov/api/v1/agencies/383","parent_id":null,"slug":"nuclear-regulatory-commission"}],"body_html_url":"https://www.federalregister.gov/documents/full_text/html/2026/09/22/2026-19300.html","cfr_references":[],"citation":"91 FR 60157","comment_url":null,"comments_close_on":null,"correction_of":null,"corrections":[],"dates":"RG 1.59, Revision 3 and RG 1.256, Revision 0 are available on September 22, 2026.","disposition_notes":null,"docket_ids":["NRC-2024-0110"],"dockets":[{"supporting_documents":[{"title":"DG 1417 GUIDANCE FOR ASSESSMENT OF FLOODING HAZARDS DUE TO WATER CONTROL STRUCTURE FAILURES","document_id":"NRC-2024-0110-0003"},{"title":"DG 1290 DESIGN BASIS FLOODS FOR NUCLEAR POWER PLANTS","document_id":"NRC-2024-0110-0002"}],"agency_name":"NRC","documents":[{"comment_count":0,"comment_start_date":"2026-09-22","updated_at":"2026-09-22T09:57:27.405-04:00","comment_url":"https://www.regulations.gov/commenton/NRC-2024-0110-0008","allow_late_comments":false,"id":"NRC-2024-0110-0008","comment_end_date":null,"regulations_dot_gov_open_for_comment":false}],"supporting_documents_count":2,"id":"NRC-2024-0110","title":"Design-Basis Floods for Nuclear Power Plants and Guidance for Assessment of Flooding Hazards due to Water Control Structure Failures and Incidents"}],"document_number":"2026-19300","effective_on":null,"end_page":60158,"executive_order_notes":null,"executive_order_number":null,"full_text_xml_url":"https://www.federalregister.gov/documents/full_text/xml/2026/09/22/2026-19300.xml","html_url":"https://www.federalregister.gov/documents/2026/09/22/2026-19300/regulatory-guides-design-basis-floods-for-nuclear-power-plants-and-guidance-for-assessment-of","images":{},"images_metadata":{},"json_url":"https://www.federalregister.gov/api/v1/documents/2026-19300?publication_date=2026-09-22","mods_url":"https://www.govinfo.gov/metadata/granule/FR-2026-09-22/2026-19300/mods.xml","not_received_for_publication":null,"page_length":2,"page_views":{"count":164,"last_updated":"2026-10-23 06:15:04 -0400"},"pdf_url":"https://www.govinfo.gov/content/pkg/FR-2026-09-22/pdf/2026-19300.pdf","presidential_document_number":null,"proclamation_number":null,"public_inspection_pdf_url":"https://public-inspection.federalregister.gov/2026-19300.pdf?1789994710","publication_date":"2026-09-22","raw_text_url":"https://www.federalregister.gov/documents/full_text/text/2026/09/22/2026-19300.txt","regulation_id_number_info":{},"regulation_id_numbers":[],"regulations_dot_gov_info":{"supporting_documents":[{"title":"DG 1417 GUIDANCE FOR ASSESSMENT OF FLOODING HAZARDS DUE TO WATER CONTROL STRUCTURE FAILURES","document_id":"NRC-2024-0110-0003"},{"title":"DG 1290 DESIGN BASIS FLOODS FOR NUCLEAR POWER PLANTS","document_id":"NRC-2024-0110-0002"}],"comments_count":0,"agency_id":"NRC","comments_url":"https://www.regulations.gov/docketBrowser?rpp=50&so=DESC&sb=postedDate&po=0&dct=PS&D=NRC-2024-0110","supporting_documents_count":2,"docket_id":"NRC-2024-0110","document_id":"NRC-2024-0110-0008","regulation_id_number":null,"title":"Design-Basis Floods for Nuclear Power Plants and Guidance for Assessment of Flooding Hazards due to Water Control Structure Failures and Incidents","checked_regulationsdotgov_at":"2026-09-23T15:55:08Z"},"regulations_dot_gov_url":null,"significant":null,"signing_date":null,"start_page":60157,"subtype":null,"title":"Regulatory Guides: Design-Basis Floods for Nuclear Power Plants and Guidance for Assessment of Flooding Hazards Due to Water Control Structure Failures and Incidents","toc_doc":"Design-Basis Floods for Nuclear Power Plants and  Guidance for Assessment of Flooding Hazards due to Water Control Structure Failures and Incidents","toc_subject":"Regulatory Guide","topics":[],"type":"Notice","volume":91}