Long-Term Cooling and Unattended Water Makeup of Spent Fuel Pools

<RULE> NUCLEAR REGULATORY COMMISSION <CFR>10 CFR Part 50</CFR> <DEPDOC>[NRC-2011-0069]</DEPDOC> <SUBJECT>Long-Term Cooling and Unattended Water Makeup of Spent Fuel Pools</SUBJECT> <HD SOURCE="HED">AGENCY:</HD> Nuclear Regulatory Commission. <HD SOURCE="HED">ACTION:</HD> Discontinuation of rulemaking activity; denial of petition for rulemaking. <SUM> <HD SOURCE="HED">SUMMARY:</HD> The U.S. Nuclear Regulatory Commission (NRC) is discontinuing a rulemaking activity, “Long-Term and Unattended Water Makeup of Spent Fuel Pools,” and denying a petition for rulemaking. The petitioner requested that the NRC amend its regulations to require that nuclear power plant licensees ensure long-term cooling and unattended water makeup of spent fuel pools (SFPs). The purpose of this action is to inform members of the public that this rulemaking activity is being discontinued and to provide a brief discussion of the NRC's decision to discontinue the rulemaking and deny the aspects of the petition not previously addressed by the NRC. </SUM> <EFFDATE> <HD SOURCE="HED">DATES:</HD> Effective May 7, 2025. </EFFDATE> <HD SOURCE="HED">ADDRESSES:</HD> Please refer to Docket ID NRC-2011-0069 when contacting the NRC about the availability of information for this action. You may obtain publicly available information related to this action by any of the following methods: • <E T="03">Federal Rulemaking Website:</E> Go to <E T="03">https://www.regulations.gov</E> and search for Docket ID NRC-2011-0069. Address questions about NRC dockets to Helen Chang; telephone: 301-415-3228; email: <E T="03">Helen.Chang@nrc.gov</E> . For technical questions, contact the individuals listed in the <E T="02">FOR FURTHER INFORMATION CONTACT</E> section of this document. • <E T="03">NRC's Agencywide Documents Access and Management System (ADAMS):</E> You may obtain publicly available documents online in the ADAMS Public Documents collection at <E T="03">https://www.nrc.gov/reading-rm/adams.html.</E> To begin the search, select “Begin Web-based ADAMS Search.” For problems with ADAMS, please contact the NRC's Public Document Room (PDR) reference staff at 1-800-397-4209, at 301-415-4737, or by email to <E T="03">PDR.Resource@nrc.gov.</E> For the convenience of the reader, instructions about obtaining materials referenced in this document are provided in the “Availability of Documents” section. • <E T="03">NRC's PDR:</E> The PDR, where you may examine and order copies of publicly available documents, is open by appointment. To make an appointment to visit the PDR, please send an email to <E T="03">PDR.Resource@nrc.gov</E> or call 1-800-397-4209 or 301-415-4737, between 8 a.m. and 4 p.m. eastern time, Monday through Friday, except Federal holidays. <FURINF> <HD SOURCE="HED">FOR FURTHER INFORMATION CONTACT:</HD> Christopher Prescott, Office of Nuclear Material Safety and Safeguards, telephone: 301-287-9452; email: <E T="03">Christopher.Prescott@nrc.gov;</E> or Jason Paige, Office of Nuclear Reactor Regulation, telephone: 301-415-1474; email: <E T="03">Jason.Paige@nrc.gov.</E> Both are staff of the U.S. NRC, Washington, DC 20555-0001. </FURINF> <SUPLINF> <HD SOURCE="HED">SUPPLEMENTARY INFORMATION:</HD> <HD SOURCE="HD1">I. Background</HD> The NRC received a petition for rulemaking (PRM), dated March 14, 2011, submitted by Thomas Popik on behalf of the Foundation for Resilient Societies. On March 15, 2011, the petition was docketed by the NRC as PRM-50-96. The petitioner requested that the NRC amend its regulations to require facilities licensed by the NRC under part 50, “Domestic Licensing of Production and Utilization Facilities,” of title 10 of the <E T="03">Code of Federal Regulations</E> (10 CFR) to address concerns about the effects of a long-term commercial grid outage on the long-term cooling and unattended water makeup of SFPs. The petitioner asserted that the North American commercial electric power grids are vulnerable to a prolonged outage caused by extreme space weather, such as coronal mass ejections and associated geomagnetic disturbances and therefore cannot be relied on to provide continual power for active cooling and/or water makeup of SFPs. Moreover, the petitioner stated that existing means of onsite backup power are designed to operate for only a few days, while spent fuel requires active cooling for several years after removal of the fuel rods from the reactor core. The petitioner suggested the following rule language for 10 CFR part 50: <EXTRACT> Licensees shall provide reliable emergency systems to provide long-term cooling and water makeup for spent fuel pools using only on-site power sources. These emergency systems shall be able to operate for a period of two years without human operator intervention and without offsite fuel resupply. Backup power systems for spent fuel pools shall be electrically isolated from other plant electrical systems during normal and emergency operation. If weather-dependent power sources are to be used, sufficient water or power storage must be provided to maintain continual cooling during weather conditions which may temporarily constrict power generation. </EXTRACT> On May 6, 2011, the NRC published a notice of receipt and request for public comment for this petition in the <E T="04">Federal Register</E> (76 FR 26223). The public comment period closed on July 20, 2011, and the NRC received 97 public comments. After reviewing public comments and evaluating other ongoing activities, the NRC performed a preliminary review and analysis to ascertain the validity, accuracy, and efficacy of the petitioner's technical assertions and proposed amendment of 10 CFR part 50. On December 18, 2012, the NRC closed the docket for PRM-50-96 by publishing a document in the <E T="04">Federal Register</E> (77 FR 74788) stating that the NRC would, in a phased approach, consider the PRM issues in the NRC rulemaking process. This document also stated that the NRC would monitor the progress of the rulemaking efforts that would eventually become the “Mitigation of Beyond-Design-Basis Events” (MBDBE) final rule to determine whether the requirements established therein would address the issues raised in PRM-50-96. On August 9, 2019, the NRC published the MBDBE final rule (84 FR 39684), which partially resolved this PRM because it requires, in part, that licensees have plans to acquire and use offsite assistance and resources to support the functions of maintaining or restoring core cooling, containment, and SFP cooling capabilities during an extended loss of alternating current power. Furthermore, in the preamble for the MBDBE final rule, the Commission stated that the NRC would address the remaining issues in PRM-50-96 following the completion of the MBDBE rulemaking. A discussion of the NRC's decision to discontinue this rulemaking activity and deny PRM-50-96 is provided in section II of this document. <HD SOURCE="HD1">II. Discussion</HD> <HD SOURCE="HD2">A. Basis for Denying the Petition and Discontinuing Rulemaking Activity</HD> The NRC will discontinue rulemaking activities associated with PRM-50-96 and deny aspects of the petition related to the two issues that were not fully addressed by the MBDBE final rule. The first such issue was that current NRC regulations do not require power reactor licensees to undertake mitigating efforts for prolonged grid failure scenarios that could be caused by geomagnetically induced currents resulting from an extreme solar storm. The second issue was the petitioner's request that licensees be required to have emergency systems to assure long-term cooling and water makeup of SFPs capable of operating for a period of 2 years without human intervention and without offsite fuel resupply. These concerns not resolved by the MBDBE final rule have been addressed by other industry and government action, as described below. Since 2012, there have been improvements in electrical grid resilience to geomagnetic disturbances and overall knowledge regarding the potential impacts of geomagnetic disturbances that address, in large part, the unresolved aspects of the PRM. The current understanding is that geomagnetic disturbances may cause localized grid failures but are unlikely to cause a widespread, long-term grid failure. This is demonstrated by improvements in space weather induced geoelectric field modeling through research sponsored by the United States Geological Survey, National Oceanic and Atmospheric Administration (NOAA), and the National Aeronautics and Space Administration (see examples listed in section III of this document), in conjunction with industry efforts to quantify the associated risk to the power grid such as the 2017 Electric Power Research Institute (EPRI) report, “Magnetohydrodynamic Electromagnetic Pulse Assessment of the Continental U.S. Electric Grid: Voltage Stability Analysis.” Additionally, the Federal Energy Regulatory Commission has worked to improve the resiliency of the grid to geomagnetic disturbances by implementing improved standards such as the North American Electric Reliability Corporation (NERC) TPL-007-4, “Transmission System Planned Performance for Geomagnetic Disturbance Events.” Currently, more than 80 percent of extra high voltage transformers are resistant against the effects of geomagnetically induced currents. With TPL-007-4 in effect, a widespread, long-term grid failure is unlikely because such grid failure is largely driven by failure of extra high voltage transformers that are now subject to standards for vulnerability assessments and associated corrective action plans. Moreover, improvements in space weather monitoring allow grid operators to take actions that can protect grid equipment. Grid operators are directly engaged with NOAA—Space Weather Prediction Center (SWPC). For example, the SWPC provides grid operators with tim ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Preview showing 10k of 24k characters. Full document text is stored and available for version comparison. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━