The purpose of the standard: ANSI/ANS-54.8.2025 establishes guidelines and requirements to ensure that the functional performance of the liquid metal fire detection, alarm, suppression, control, and structural protection systems is adequate to protect the health and safety of the public and plant personnel, and to minimize or limit the economic loss in the event of a sodium/NaK leak.
It sets forth guidelines and minimum design requirements for preventing, detecting, and suppressing liquid metal fires and mitigating their consequences in LMR plants. The intent of this standard is to provide requirements and guidance on those aspects of fire prevention and protection that are not covered in other codes and standards.
It is not intended to be a total plant fire protection standard and therefore does not supersede other applicable codes and standards of fire protection. Nothing in this standard is intended to prevent the use of new fire protection methods, provided that sufficient technical data are available to demonstrate that the new method or device provides an equivalent level of safety and reliability as prescribed by this standard.
This standard applies to those plant protection and operating features specifically designed to prevent or mitigate the consequences of significant sodium/NaK spill accidents in nuclear power plants. It does not address those accidents involving sodium–water reactions within the boundary of the steam generators. It does not apply to liquid metals other than sodium/NaK.
From idea to print: The ARCSC was formed in 2022 to meet the needs of stakeholders supporting advanced reactor designs currently planned or in progress. This collaborative ensures coordination and engagement among standards development organizations, reactor designers, regulators, and other interested stakeholders to develop a roadmap of needs for new or updated codes and standards.
With feedback from the ARCSC survey, the ANS Standards Board approved an effort to reissue ANS-54.8 as soon as possible with only minor updates from the 1988 version. This pace of this reissue was expedited, because no other existing standards were available on the subject matter and the 1988 version was being utilized and referenced even in its withdrawn state.
The effort to reissue ANS-54.8 was officially initiated on June 12, 2024, with the submittal of a Project Initiation Notification Systems (PINS) form to ANSI. ANSI approval of the 2025 edition was achieved just over 15 months later. With the average standard taking six years or more to be developed and approved, 15 months is lightning speed in the standards world and a significant accomplishment for the ANS-54.8 Working Group.
ANSI/ANS-54.8-2025, Liquid Metal Fire Protection in LMR Plants, received approval from the American National Standards Institute on September 2 and is now available for purchase.
