3150-AH43 201410 The Regulatory Plan and the Unified Agenda of Federal Regulatory and Deregulatory Actions 3150 Nuclear Regulatory Commission NRC Decoupling of Assumed Loss of Offsite Power (LOOP) From Loss-of-Coolant Accidents (LOCA) [NRC-2008-0606]

The proposed rule would amend the Commission's regulations to remove the requirement to postulate unavailability of offsite power for all loss of coolant accidents, as currently required by General Design Criterion 35. By taking into account risk insights, this requirement would be removed for the larger, less likely events but would be retained for more frequent (smaller break) losses of coolant. The rulemaking would facilitate certain facility changes, such as changing emergency diesel generator start times, to optimize them for the more likely events rather than for rare events.

]]> Substantive, Nonsignificant Previously Published in The Unified Agenda Long-Term Actions Undetermined No 10 CFR 50 42 USC 2201 42 USC 5841 No NPRM To Be Determined In a Staff Requirements Memorandum (SRM) dated March 31, 2003, the Commission directed the staff to prepare a proposed LOOP/LOCA rule. On April 27, 2004, the Boiling Water Reactor (BWR) Owners Group (BWROG) submitted the topical report, "Separation of Loss of Offsite Power from Large Break LOCA" for staff review. The BWROG indicated that the topical report would support plant-specific exemption requests to implement specific plant changes that are currently not possible with the existing rule requirements. The staff recommended in SECY-04-0037, that it be allowed to finish its review of the topical report and pilot exemption request before initiating rulemaking. In its SRM of July 1, 2004, the Commission approved the staff to begin rulemaking after review of the BWROG pilot exemption request. After an ongoing dialogue, on June 12, 2008, the BWROG withdrew its topical report, stating that "continued development of this LTR [Licensing Topical Report] is no longer cost effective and, if ultimately approved in the form presently desired by NRC staff, adoption by licensees would most likely be prohibitively expensive." Upon this withdrawal, the NRC staff reevaluated the rulemaking effort. As a result of this reevaluation, the NRC staff recommended in SECY-09-0140, dated October 1, 2009, that this rulemaking effort be discontinued. The Commission issued its SRM on SECY-09-014 on July 2, 2010, directing the staff to defer the decision on continuing the rulemaking until after the 10 CFR 50.46a rule is implemented and the staff obtains feedback from industry on the potential incremental benefit of a separate LOOP/LOCA rule. The staff provided the draft 10 CFR 50.46a final rule to the Commission on December 10, 2010. On April 26, 2012, the NRC staff withdrew the draft final rule but intends to resubmit it to the Commission, after ensuring that any potential changes to NRC's regulatory framework after evaluating Fukushima NTTF Recommendation 1 and the Risk-Management Regulatory Framework proposed in NUREG-2150 are consistent with the approach in the draft final rule. Because the schedule for resubmitting the draft final 10 CFR 50.46a rule to the Commission is uncertain, the schedule for reevaluating the need for a LOOP/LOCA rule is undetermined. This rulemaking activity also considers the issues raised in a petition for rulemaking submitted by Bob Christie (PRM-50-77). No No None No No No 3150-AH29 Related to Tara Inverso 3150 Nuclear Regulatory Commission NRC 301 415-1024 tara.inverso@nrc.gov Office of Nuclear Reactor Regulation, Washington DC 20555-0001