ML18071A197

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Plan, Units 1 and 2 - Documentation of the Completion of Required Actions Taken in Response to the Lessons Learned from the Fukushima Dai-Ichi Accident
ML18071A197
Person / Time
Site: Calvert Cliffs  Constellation icon.png
Issue date: 03/28/2018
From: Lund A
Division of Licensing Projects
To: Bryan Hanson
Exelon Generation Co, Exelon Nuclear
Bernardo R
References
Download: ML18071A197 (27)


Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 March 28, 2018 Mr. Bryan C. Hanson Senior Vice President Exelon Generation Company, LLC President and Chief Nuclear Officer Exelon Nuclear 4300 Winfield Rd Warrenville, IL 60555

SUBJECT:

CALVERT CLIFFS NUCLEAR POWER PLANT, UNITS 1 AND 2 -

DOCUMENTATION OF THE COMPLETION OF REQUIRED ACTIONS TAKEN IN RESPONSE TO THE LESSONS LEARNED FROM THE FUKUSHIMA DAI-ICHI ACCIDENT

Dear Mr. Hanson:

The purpose of this letter is to acknowledge and document that actions required by the U.S. Nuclear Regulatory Commission (NRC) in orders issued following the accident at the Fukushima Dai-ichi Nuclear Power Station have been completed for Calvert Cliffs Nuclear Power Plant, Units 1and 2 (Calvert Cliffs). In addition, this letter acknowledges and documents that Exelon Generation Company, Inc (Exelon, the licensee) has provided the information requested in the NRC's March 12, 2012, request for information under Title 1O of the Code of Federal Regulations (10 CFR), Section 50.54(f), related to the lessons learned from that accident. Completing these actions and providing the requested information, in conjunction with the regulatory activities associated with the Mitigation of Beyond-Design-Basis Events (MBDBE) rulemaking, implements the safety enhancements mandated by the NRC based on the lessons learned from the accident. Relevant NRC, industry, and licensee documents are listed in the reference tables provided in the enclosure to this letter. The NRC will provide oversight of these safety enhancements through the Reactor Oversight Process (ROP).

BACKGROUND In response to the events in Japan resulting from the Great Tohoku Earthquake and subsequent tsunami on March 11, 2011, the NRC took immediate action to confirm the safety of U.S.

nuclear power plants:

  • On March 18, 2011, the NRC issued Information Notice 2011-05, "Tohoku-Taiheiyou-Oki Earthquake Effects on Japanese Nuclear Power Plants" (Reference 1.1 ). The information notice was issued to inform U.S. operating power reactor licensees and applicants of the effects from the earthquake and tsunami. Recipients were expected to review the information for applicability to their facilities and consider actions, as appropriate.

Suggestions contained in an information notice are not NRC requirements; therefore, no specific action or written response was required.

B. Hanson

  • On March 23, 2011, the NRC issued Temporary Instruction (Tl) 2515/183, "Followup to the Fukushima Daiichi Fuel Damage Event." The purpose of Tl 2515/183 was to provide NRC inspectors with guidance on confirming the reliability of licensees' strategies intended to maintain or restore core cooling, containment, and spent fuel pool cooling capabilities following events that may exceed the design-basis for a plant. The results of the inspection for each licensee were documented in an inspection report (Reference 1.2).
  • On March 23, 2011, the Commission provided staff requirements memorandum (SRM)

COMGBJ-11-0002, "NRC Actions Following the Events in Japan." The tasking memorandum directed the Executive Director for Operations to establish a senior level agency task force, referred to as the Near-Term Task Force (NTTF), to conduct a methodical and systematic review of the NRC processes and regulations to determine whether the agency should make additional improvements to the regulatory system and make recommendations to the Commission within 90 days for its policy direction (Reference 1.3).

  • On April 29, 2011, the NRC issued Tl 2515/184, "Availability and Readiness Inspection of Severe Accident Management Guidelines (SAMGs)." The purpose of Tl 2515/184 was to inspect the readiness of nuclear power plant operators to implement SAMGs. The results of the inspection were summarized and provided to the NTTF, as well as documented in a 2011 quarterly integrated inspection report for each licensee (Reference 1.4).
  • On May 11, 2011, the NRC issued Bulletin (BL) 2011-01, "Mitigating Strategies."

BL 2011-01 required licensees to provide a comprehensive verification of their compliance with the regulatory requirements of 10 CFR 50.54(hh)(2), as well as provide information associated with the licensee's mitigation strategies under that section. In 10 CFR 50.54{hh)(2), it states, in part: "Each licensee shall develop and implement guidance and strategies intended to maintain or restore core cooling, containment, and spent fuel pool cooling capabilities under the circumstances associated with loss of large areas of the plant due to explosions or fire .... " BL 2011-01 required a written response from each licensee (Reference 1.5).

  • On July 21, 2011, the NRC staff provided the NTTF report, "Recommendations for Enhancing Reactor Safety in the 21 51 Century: The Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident" to the Commission in SECY-11-0093, "Near-Term Report and Recommendations for Agency Actions Following the Events in Japan" (Reference 1.6).
  • On October 3, 2011, the staff prioritized the NTTF recommendations into three tiers in SECY-11-0137, "Prioritization of Recommended Actions To Be Taken in Response to Fukushima Lessons Learned." The Commission approved the staff's prioritization, with comment, in the SRM to SECY-11-0137 (Reference 1.7).

A complete discussion of the prioritization of the recommendations from the NTTF report, additional issues that were addressed subsequent to the NTTF report, and the disposition of the issues that were prioritized as Tier 2 or Tier 3 is provided in SECY-17-0016, "Status of Implementation of Lessons Learned from Japan's March 11, 2011, Great Tohoku Earthquake and Subsequent Tsunami" (Reference 12.10). A listing of the previous Commission status reports, which were provided semiannually, can be found in Table 12 in the enclosure to this letter.

B. Hanson The NRC undertook the following regulatory activities to address the majority of the Tier 1 recommendations:

  • On March 12, 2012, the NRC issued Orders EA-12-049, "Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events,"

EA-12-050, "Order Modifying Licenses with Regard to Reliable Hardened Containment Vents," and EA-12-051, "Order Modifying Licenses with Regard to Reliable Spent Fuel Pool Instrumentation," and a request for information under 10 CFR 50.54(f) (hereafter referred to as the 50.54(f) letter) to licensees (References 1.8, 1.9, 1.10, and 1.11, respectively).

  • On June 6, 2013, the NRC issued Order EA-13-109, "Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation under Severe Accident Conditions" (Reference 1.12), which superseded Order EA-12-050, replacing its requirements with modified requirements.
  • In addition to the three orders and the 50.54(f) letter, the NRC is considering a new regulation (10 CFR 50.155, "Mitigation of Beyond-Design-Basis Events"). The draft final rule and supporting documentation were provided to the Commission for approval in SECY-16-0142, "Draft Final Rule - Mitigation of Beyond-Design-Basis Events (RIN 3150-AJ49)" (Reference 1.13). The MBDBE rulemaking would consolidate several of the recommendations from the NTTF report. The draft final rule, as provided to the Commission, contains provisions that make generically applicable the requirements imposed by Orders EA-12-049 and EA-12-051 and supporting requirements for the integrated response capability that includes staffing, communications, training, drills or exercises, and documentation of changes. The draft final rule also contains requirements for licensees to consider the effects of the reevaluated seismic and flooding hazard information identified in response to Enclosures 1 and 2 of the 50.54(f) letter. Three proposed regulatory guides (References 1. 14, 1.15, and 1.16) were included to provide methods and procedures that the NRC staff considers acceptable for licensees to demonstrate compliance with the MBDBE rule, if approved by the Commission.

This letter acknowledges and documents that the actions required by the NRC in response to the orders, as well as the information provided in response to the March 12, 2012, 50.54(f) letter, have been completed for Calvert Cliffs. However, the staff is not determining whether the licensee complies with the draft final MBDBE rule. Oversight of compliance with the draft final MBDBE rule at Calvert Cliffs will be conducted through the ROP, if the Commission approves the rule.

DISCUSSION Mitigation Strategies Order Order EA-12-049, which applies to Calvert Cliffs, requires licensees to implement a three-phase approach for mitigation of beyond-design-basis external events (BDBEEs). It requires licensees to develop, implement, and maintain guidance and strategies to maintain or restore core cooling, containment, and spent fuel pool (SFP) cooling capabilities in the event of a BDBEE that results in a simultaneous loss of all alternating current (ac) power and loss of normal access to the ultimate heat sink (LUHS). Phases 1 and 2 of the order use onsite equipment,

B. Hanson while Phase 3 requires obtaining sufficient offsite resources to sustain those functions indefinitely.

In August 2012, the Nuclear Energy Institute (NEI) issued industry guidance document NEI 12-06, "Diverse and Flexible Coping Strategies (FLEX) Implementation Guide," as guidance to comply with the order. The NRC endorsed the guidance in Japan Lessons-Learned Project Directorate (JLD) interim staff guidance (ISG) document JLD-ISG-2012-01, "Compliance with Order EA-12-049, Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events" (Reference 2.1 ). Licensees were required to provide an overall integrated plan (OIP) to describe how they would comply with the order, along with status reports every 6 months until compliance was achieved (Reference 2.2). The NRC staff provided an interim staff evaluation (ISE) related to the OIP (Reference 2.3). The NRC concluded in the ISE that the licensee provided sufficient information to determine that there is reasonable assurance that the plan, when properly implemented, including satisfactory resolution of the open and confirmatory items, would meet the requirements of Order EA-12-049 at Calvert Cliffs. The NRC staff also conducted a regulatory audit of the licensee's strategies and issued a report which documented the results of the audit activities (Reference 2.4). Upon reaching compliance with the order requirements, the licensee submitted a compliance letter and a final integrated plan (FIP) to the NRC (Reference 2.5). The FIP describes how the licensee is complying with the order at Calvert Cliffs.

The NRC staff completed a safety evaluation (SE) of the licensee's FIP (Reference 2.6). The SE informed the licensee that its integrated plan, if implemented as described, provided a reasonable path for compliance with Order EA-12-049 at Calvert Cliffs. The staff then evaluated the implementation of the plans through inspection, using Tl 2515/191, "Implementation of Mitigation Strategies and Spent Fuel Pool Instrumentation Orders and Emergency Preparedness Communications/Staffing/Multi-Unit Dose Assessment Plans." An inspection report was issued to document the results of the Tl 2515/191 inspection (Reference 2. 7). The NRC will oversee implementation of the mitigation strategies requirements under the proposed MBDBE rule requirements, if approved by the Commission, through the ROP.

Phase 3 of Order EA-12-049 required licensees to obtain sufficient offsite resources to sustain the required functions indefinitely. There are two redundant National Strategic Alliance for FLEX Emergency Response (SAFER) Response Centers (NSRCs), one located in Memphis, Tennessee, and the other in Phoenix, Arizona, which have the procedures and plans in place to maintain and deliver the equipment needed for Phase 3 from either NSRC to any participating U.S. nuclear power plant when requested (Reference 2.8). The NRC staff evaluated and inspected the NSRCs and the SAFER program, plans, and procedures (References 2.9 and 2.10). The NRC concluded that licensees may reference the SAFER program and implement their SAFER response plans to meet the Phase 3 requirements of the order. The licensee's FIP (Reference 2.5) includes the plans for utilizing the NSRC equipment at Calvert Cliffs. In its SE (Reference 2.6), the NRC staff concluded that the licensee has developed guidance that, if implemented appropriately, should allow utilization of offsite resources following a BDBEE consistent with NEI 12-06 guidance and should adequately address the requirements of the order.

Spent Fuel Pool Instrumentation Order Order EA-12-051, which applies to Calvert Cliffs, required licensees to install reliable SFP level instrumentation with a primary channel and a backup channel, independent of each other, and with the capability to be powered independent of the plant's power distribution systems. The

B. Hanson NEI issued NEI 12-02, "Industry Guidance for Compliance with NRC Order EA-12-051, 'To Modify Licenses with Regard to Reliable Spent Fuel Pool Instrumentation,"' as guidance to be used by licensees to comply with the order. The NRC endorsed this guidance in JLD-ISG-2012-03, "Compliance with Order EA-12-051, Reliable Spent Fuel Pool Instrumentation" (Reference 3.1 ). Licensees were required to provide an OIP to describe how they would comply with the order, along with status reports every 6 months until compliance was achieved (Reference 3.2). The NRC issued an ISE, providing feedback on the OIP (Reference 3.3). The NRC staff conducted a regulatory audit of the licensee's strategies and issued a report that documented the results of the audit activities (Reference 3.4). Upon reaching compliance with the order requirements, the licensee submitted a compliance letter to the NRC (Reference 3.5), describing how the licensee complied with the order at Calvert Cliffs.

The NRC staff completed an SE of the actions taken by the licensee in response to the order (Reference 3.6). The SE informed the licensee that its integrated plan, if implemented as described, provided a reasonable path for compliance with Order EA-12-051 at Calvert Cliffs.

The staff then evaluated the implementation of the plan through inspection, using Tl 2515/191.

An inspection report was issued to document the results of the Tl 2515/191 inspection (Reference 3. 7). The NRC will oversee implementation of the SFP instrumentation requirements under the proposed MBDBE rule requirements, if approved by the Commission, through the ROP.

Reliable Hardened Containment Vent Order Order EA-13-109 is only applicable to operating boiling-water reactors (BWRs) with Mark I and Mark II containments. Because the reactors at Calvert Cliffs are pressurized water reactors with large, dry, ambient pressure containments, this order is not applicable to Calvert Cliffs.

Request for Information Under 10 CFR 50.54(f)

The 50.54(f) letter requested operating power reactor licensees to:

  • reevaluate the seismic and flooding hazard at their sites using present-day NRC requirements and guidance, and identify actions that are planned to address plant-specific vulnerabilities associated with the reevaluated seismic and flooding hazard;
  • perform seismic and flooding walkdowns to verify compliance with the current licensing basis; verify the adequacy of current strategies and maintenance plans; and identify degraded, nonconforming, or unanalyzed conditions related to seismic and flooding protection; and
  • provide an assessment of their current emergency communications and staffing capabilities to determine if any enhancements are needed to respond to a large-scale natural emergency event that results in an extended loss of ac power to all reactors at the site, and/or impeded access to the site.

In COMSECY-14-0037, "Integration of Mitigating Strategies for Beyond-Design-Basis External Events and the Reevaluat[i]on of Flooding Hazards" (Reference 6.13), the NRC staff described issues related to the implementation of Order EA-12-049 and the related MBDBE rulemaking, and the completion of flooding reevaluations and assessments. In the SRM to COMSECY-14-0037 (Reference 6.14), the Commission directed the NRC staff to ensure that

B. Hanson licensees of operating nuclear power plants address the reevaluated hazard within their mitigation strategies for BDBEE. The SRM also directed the NRC staff to provide a plan for achieving closure of the flooding hazard assessments to the Commission for review and approval. The NRC staff provided this plan in COMSECY-15-0019, "Closure Plan for the Reevaluation of Flooding Hazards for Operating Nuclear Power Plants" (Reference 6.16), which the Commission approved in the SRM to COMSECY-15-0019 (Reference 6.17).

Hazard Reevaluations (Enclosures 1 and 2 of the 50.54(f) letter)

Each licensee followed a similar two-phase process to respond to the hazard reevaluations requested by the 50.54(f) letter. In Phase 1, licensees submitted hazard reevaluation reports using NRG-endorsed, industry-developed guidance. The guidance specified that a licensee should determine if interim protection measures were needed while a longer-term evaluation of the impacts of the hazard was completed. The NRC staff reviewed the reevaluated hazard information. Using the reevaluated hazard information and a graded approach, the NRC identified the need for, and prioritization and scope of, plant-specific assessments. For those plants that were required to perform a flooding integrated assessment or a seismic probabilistic risk assessment (SPRA), Phase 2 decisionmaking (as described in a letter dated September 16, 2016 (Reference 5.17)) would determine whether additional plant-specific regulatory actions were necessary. In addition, as discussed in COMSECY-15-0019 and the draft final MBDBE rule, each licensee performed a mitigation strategies assessment (MSA) to confirm that the licensee had adequately addressed the reevaluated hazards within their mitigation strategies developed for BDBEEs.

Seismic Hazard Reevaluation (Enclosure 1 of the 50.54(f) letter) of the 50.54(f) letter requested each operating power reactor licensee to complete a reevaluation of the seismic hazard that could affect their sites using updated seismic hazard information and present-day regulatory guidance and methodologies to develop a ground motion response spectrum (GMRS). The licensee was asked to compare their results to the safe-shutdown earthquake (SSE) ground motion and then report to the NRC in a seismic hazard screening report. To provide a uniform and acceptable industry response, the Electric Power Research Institute (EPRI) developed a technical report, EPRI 1025287, "Screening, Prioritization and Implementation Details (SPID) for the Resolution of Fukushima Near-Term Task Force Recommendation 2.1: Seismic," and the NRC endorsed the guidance in a letter dated February 15, 2013 (Reference 5.1). From November 2012 to May 2014, the NRC and the industry provided guidance for the performance of the reevaluated hazard reviews (References 5.2-5. 7). The licensee provided a seismic hazard screening report for Calvert Cliffs (Reference 5.8).

If the new GMRS was not bound by the current design basis (COB) SSE, Enclosure 1 of the 50.54(f) letter requested more detailed evaluations of the impact from the hazard. Also, the licensee was asked to evaluate whether interim protection measures were needed while the more detailed evaluation was completed. By letter dated May 7, 2013, the NRC endorsed industry-developed guidance, a proposed path forward, and schedules, which were provided in a letter from NEI dated April 9, 2013. Attachment 1 of the NEI letter contains EPRI report 300200704, "Augmented Approach for the Resolution of Fukushima Near-Term Task Force Recommendation 2.1: Seismic," to provide the guidance needed to perform an evaluation of any needed interim protective measures (Reference 5.3). This expedited seismic evaluation process (ESEP) is a screening, evaluation, and equipment modification process performed by licensees to provide additional seismic margin and expedite plant safety

B. Hanson enhancements for certain core cooling and containment components while the more detailed and comprehensive plant seismic risk evaluations are being performed. Because an ESEP was required for Calvert Cliffs (see References 5.10 and 5.11 ), the licensee submitted an ESEP report, the NRC staff completed a technical review of the ESEP report, and documented its review in a response letter (Reference 5.13).

By letter dated May 9, 2014 (Reference 5.10), the NRC informed licensees of the initial screening and prioritization results based on a review of the licensees' seismic hazard screening reports. The NRC updated the screening and prioritization in a letter dated October 3, 2014 (Reference 5.11 ). The NRC provided the final determination of required seismic evaluations in a letter dated October 27, 2015 (Reference 5.18). These evaluations could consist of an SPRA (Reference 5.1, SPID, Section 6.1.1 ), limited scope evaluations (High Frequency (Reference 5.14) and/or SFP (Reference 5.15)), or a relay chatter evaluation (Reference 5.4). If an SPRA was required, then additional Phase 2 regulatory decisionmaking was required (References 5.16 and 5.17).

The NRC staff completed and documented its review of the licensee's reevaluated seismic hazard in a staff assessment (Reference 5.9). In order to complete its response to the 50.54(f) letter (Reference 5.18), the licensee submitted a high frequency confirmation report and a SFP evaluation for Calvert Cliffs (Reference 5.19). The NRC reviewed the high frequency confirmation submittal (Reference 5.21) and confirmed that Calvert Cliffs met the NRC-endorsed low spectral acceleration screening criterion (Reference 5.14). The NRC reviewed the SFP evaluation (Reference 5.21) and confirmed that Calvert Cliffs is within the bounds considered in the NRG-endorsed evaluation criteria (Reference 5.15). Based on these reviews, the NRC has concluded that no additional seismic evaluations were needed in response to the 50.54(f) letter.

The NRC staff reviewed the information provided and, as documented in the staff assessments (References 5.9 and 5.21 ), determined that the licensee provided sufficient information in response to Enclosure 1 of the 50.54(f) letter. The staff acknowledges that all seismic hazard reevaluation activities requested by Enclosure 1 of the 50.54(f) letter have been completed for Calvert Cliffs. No further information related to the reevaluated seismic hazard is required.

Flooding Hazard Reevaluation (Enclosure 2 of the 50.54{D letter) of the 50.54(f) letter requested each operating power reactor licensee to complete a reevaluation of applicable flood-causing mechanisms at their site using updated flooding hazard information and present-day regulatory guidance and methodologies. Licensees were asked to compare their results to the COB for protection and mitigation from external flood events. The NRC developed guidance to conduct the reevaluations (References 6.1 through 6.6). The licensee submitted a flood hazard reevaluation report (FHRR) for Calvert Cliffs (Reference 6. 7) to the NRC as requested by the 50.54(f) letter. Interim actions needed to protect against the reevaluated hazard were specified in the FHRR. The NRC inspected the interim actions using Tl 2515/190, "Inspection of Licensee's Proposed Interim Actions as a Result of the Near-Term Task Force Recommendation 2.1 Flooding Evaluation" and documented the results in a quarterly integrated inspection report (Reference 6.9). A regulatory audit to support the review of the FHRR was not required. The NRC staff reviewed the FHRR and the licensee's responses to requests for additional information (Reference 6.8) and provided a staff assessment (Reference 6.11 ). The NRC provided feedback to the licensee on the reevaluated flood hazards that exceeded the current design basis in a supplement to the staff assessment (Reference 6.10). The NRC staff concluded that these reevaluated hazard results were suitable

B. Hanson inputs for the licensee to complete the flood hazard MSA and other flood hazard evaluations (i.e., defines the mitigating strategies flood hazard information described in NEI 12-06).

In COMSECY-14-0037 (Reference 6.13), the NRC staff requested Commission direction to more clearly define the relationship between Order EA-12-049, the related MBOBE rulemaking, and the flood hazard reevaluations and assessments. Because the NRC was reevaluating its approach to the flooding evaluations, the NRC provided an extension of the due dates for any integrated assessments in a letter dated November 21, 2014 (Reference 6.12). In the SRM to COMSECY-14-0037 (Reference 6.14), the Commission affirmed that licensees of operating nuclear power plants need to address the reevaluated flooding hazard within their mitigation strategies. The Commission also directed the NRC staff to provide a plan for achieving closure of the flooding portion of NTTF Recommendation 2.1 to the Commission for its review and approval. On May 26, 2015, the NRC deferred, until further notice, the date for submitting the integrated assessment reports (Reference 6.15). On June 30, 2015, the NRC staff provided a plan to the Commission in COMSECY-15-0019 (Reference 6.16). On July 28, 2015, the Commission approved the plan in the SRM to COMSECY-15-0019 (Reference 6.17). On September 29, 2015, the NRC issued a letter to licensees to describe the graded approach to the flood hazard reevaluations approved by the Commission (Reference 6.18).

The COMSECY-15-0019 action plan required the NRC staff to develop a graded approach to identify the need for, and prioritization and scope of, plant-specific integrated assessments and evaluation of plant-specific regulatory actions. The NRC staff's graded approach enabled a site with hazard exceedance above its COB to demonstrate the site's ability to cope with the reevaluated hazard through appropriate protection or mitigation measures which are timely, effective, and reasonable. Integrated assessments were focused on sites with the greatest potential for additional safety enhancements. New guidance for performing the integrated assessments and focused evaluations was developed for this graded approach. The guidance also provided schedule information for submission of any required integrated assessment. On July 18, 2016, the staff issued JLO-ISG-2016-01, "Guidance for Activities Related to Near-Term Task Force Recommendation 2.1, Flooding Hazard Reevaluation, Focused Evaluation and Integrated Assessment" (Reference 6.19). The ISG provided the guidance for Phase 1 flooding assessments, as described in COMSECY-15-0019, and endorsed industry guidance provided in NEI 16-05, "External Flooding Integrated Assessment Guidelines" (Reference 6.19). If an integrated assessment was necessary, then Phase 2 regulatory decisionmaking was required (References 6.23 and 6.24).

As noted in the supplement to the staff assessment (i.e., the interim hazard response letter, Reference 6.10), the local intense precipitation (LIP) and probable maximum storm surge (PMSS) flood-causing mechanisms were not bound by the COB. Therefore, additional assessments of these flood-causing mechanisms were required. By letter dated September 23, 2015 (Reference 6.11 ), the licensee submitted an amendment to the FHRR.

The licensee revised its reevaluations for LIP and storm surge by using a site-specific probable maximum precipitation for LIP and refined hydrodynamic modeling for storm surge. The revised reevaluations resulted in a storm surge that is bounded by the COB. The NRC provided its review of the refined reevaluated hazard in its staff assessment of the licensee's flooding MSA (Reference 7.7). The NRC staff agreed with the licensee that the only flood hazard mechanism not fully bounded by the COB is LIP.

The NRC staff used a graded approach to determine if this site would be subject to an integrated assessment for the reevaluated flooding hazard, or if a more focused evaluation can be performed in lieu of the integrated assessment. Based on the graded approach, Calvert

B. Hanson Cliffs completed a focused evaluation (Reference 6.20) to ensure appropriate actions are identified and taken to protect the plant from the reevaluated flood hazard. The NRC staff conducted a regulatory audit (Reference 6.22), completed its review of the focused evaluation (Reference 6.20), and concluded in the staff assessment (Reference 6.21) that the licensee provided sufficient information in response to the 50.54(f) letter. Audit results were summarized in the staff assessment. No further regulatory actions are required related to the flood hazard reevaluations.

The NRC staff reviewed the information provided by the licensee and has concluded that sufficient information was provided to be responsive to Enclosure 2 of the 50.54(f) letter. The staff acknowledges that all flooding hazard reevaluation activities requested by Enclosure 2 of the 50.54(f) letter have been completed for Calvert Cliffs. No further information related to the reevaluated flood hazard is required.

Mitigation Strategies Assessment In addition to the closure plan for NTTF Recommendation 2.1, the action plan approved by the Commission in the SRM to COMSECY-15-0019 (Reference 7.4) identified the staff efforts to ensure licensees would address the reevaluated hazard information in their mitigation strategies. Performance of the MSA is necessary to support compliance with the final MBDBE rule, if approved by the Commission.

The objective of the MSA is to determine whether the mitigation strategies developed for Order EA-12-049 can still be implemented given the reevaluated hazard levels. If it was determined that the mitigation strategies could not be implemented for the reevaluated hazard levels, the MSA could provide other options such as performing additional evaluations, modifying existing mitigation strategies, or developing alternate mitigating strategies or targeted hazard mitigating strategies to address the reevaluated hazard levels. In Revision 1 to JLD-ISG-2012-01, the NRC endorsed industry-developed guidance contained in Appendices G and H of NEI 12-06 (Reference 7.5) for completing the MSAs.

The licensee completed both a flood hazard MSA (Reference 7.6) and a seismic hazard MSA (Reference 7.8) for Calvert Cliffs. A regulatory audit was not needed for either MSA (Reference 7.10). The NRC staff reviewed the MSA submittals, and issued staff assessments (References 7.7 and 7.9) documenting its review. The NRC staff concluded that the licensee has demonstrated that the mitigation strategies appropriately address the reevaluated hazard conditions. Oversight of any changes to existing mitigation strategies, or new strategies, resulting from the MSAs will be included in the longer-term oversight of mitigation strategies through the ROP.

Walkdowns (Enclosures 3 and 4 of the 50.54(f) letter)

Enclosures 3 and 4 of the 50.54(f) letter requested that licensees perform plant walkdowns to verify compliance with the current licensing basis as it pertains to seismic and flood protection.

By letter dated May 31, 2012 (Reference 8.2), the NRC endorsed industry-developed guidance contained in Technical Report EPRI 1025286, "Seismic Walkdown Guidance" (Reference 8.1 ),

for the performance of the seismic walkdowns. By letter dated May 31, 2012 (Reference 9.2),

the NRC endorsed industry-developed guidance contained in NEI 12-07, "Guidelines for Performing Verification Walkdowns of Plant Flood Protection Features" (Reference 9.1 ), for performance of the flooding walkdowns. The licensee provided a report for both the seismic and flooding walkdowns at Calvert Cliffs (References 8.3 and 9.3). The NRC performed onsite

B. Hanson inspections per Tl 2515/188, "Inspection of Near-Term Task Force Recommendation 2.3 Seismic Walkdowns," and Tl 2515/187, "Inspection of Near-Term Task Force Recommendation 2.3 Flooding Walkdowns," and documented the inspection results in a quarterly integrated inspection report (References 8.4 and 9.4). The NRG staff issued staff assessments for both the seismic and flooding walkdowns (References 8.6 and 9.5). Because there were inaccessible items identified during the initial licensee seismic walkdowns, the licensee submitted a subsequent seismic walkdown report after accessing the areas (Reference 8.5). The NRG documented its review of the subsequent seismic walkdown reports in a memo dated September 25, 2015 (Reference 8.7).

The NRG staff reviewed the information provided by the licensee and determined that sufficient information was provided to be responsive to Enclosures 3 and 4 of the 50.54(f) letter. The staff acknowledges that all seismic and flooding walkdown activities requested by the 50.54(f) letter have been completed for Calvert Cliffs.

Communications and Staffing (Enclosure 5 of the 50.54(f) letter) of the 50.54(f) letter requested licensees to assess their means to power equipment needed to communicate onsite and offsite during a prolonged station blackout event and to identify and implement enhancements to ensure that communications can be maintained during such an event. Also, licensees were requested to assess the staffing required to fill all necessary positions to respond to a multiunit event with impeded access to the site, or to an extended loss of all ac power for single unit sites. Licensees were requested to submit a written response to the information requests within 90 days, or provide a response within 60 days and describe an alternative course of action and estimated completion dates. The licensee proposed an alternative course of action and schedule for Calvert Cliffs (Reference 10.2), which included a 90-day partial response (Reference 10.3). The NRG acknowledged the schedule changes in a letter dated July 26, 2012 (Reference 10.4).

By letter dated May 15, 2012, the NRG endorsed industry-developed guidance contained in NEI 12-01, "Guideline for Assessing Beyond Design Basis Accident Response Staffing and Communications Capabilities" (Reference 10.1 ), for the performance of the communications and staffing assessments. The licensee provided the communications assessment and implementation schedule for Calvert Cliffs (Reference 10.5), and the NRG completed a staff assessment of the licensee's communications assessment (Reference 10.6).

Licensees responded to the staffing portion of the 50.54(f) letter in two phases to account for the implementation of mitigation strategies. Phase 1 staffing assessments were based on the existing station blackout coping strategies with an assumption of all reactors at the site being affected concurrently. The Phase 1 staffing assessment is required for multiunit sites and was completed for Calvert Cliffs (Reference 10. 7). In Phase 2, all licensees assessed the staffing necessary to carry out the mitigation strategies (Reference 10.9). The NRG staff issued staffing assessment response letters (References 10.8 and 10.10) for each submittal. The NRG performed an onsite inspection using Tl 2515/191 to verify that the emergency communications and staffing plans at Calvert Cliffs have been implemented as described by the licensee (Reference 10.11 ).

The draft final MBDBE rule would make generically applicable the staffing and communications requirements to support the mitigation strategies. Regulatory Guide 1.228 (Reference 1.16) is expected to endorse, with clarifications, NEI 12-01, NEI 13-06, "Enhancements to Emergency Response Capabilities for Beyond-Design-Basis Events and Severe Accidents"

B. Hanson (Reference 11.17), and NEI 14-01, "Emergency Response Procedures and Guidelines for Beyond-Design-Basis Events and Severe Accidents" (Reference 11. 7), to provide acceptable methods for implementing the MBDBE rule requirements, if approved. The NRC will oversee the communications and staffing requirements, and a periodic drill or exercise, under the proposed MBDBE rule requirements, if approved by the Commission, through the ROP.

The NRC staff reviewed the information provided by the licensee and determined that sufficient information was provided to be responsive to Enclosure 5 of the 50.54(f) letter. The staff acknowledges that all emergency preparedness communications and staffing activities requested by Enclosure 5 of the 50.54(f) letter have been completed for Calvert Cliffs. No further information related to the communications and staffing assessments is required.

Additional Industry Commitments Update and Maintain Severe Accident Management Guidelines The NRC staff provided the proposed MBDBE rule to the Commission on April 30, 2015, in SECY-15-0065, "Proposed Rulemaking: Mitigation of Beyond-Design-Basis Events (RIN 3150-AJ49)" (Reference 11.1) and the Commission issued the SRM to SECY-15-0065 on August 27, 2015 (Reference 11.2). The Commission approved publication of the proposed rule subject to removal of the proposed requirements pertaining to the SAMGs. The Commission also directed the staff to update the ROP to explicitly provide periodic oversight of industry's implementation of the SAMGs. By letter dated October 26, 2015 (Reference 11.3), NEI described the industry initiative, approved by the Nuclear Strategic Issues Advisory Committee as mandatory for all NEI members, to update and maintain the SAMGs. Specifically, each licensee will perform timely updates of their site-specific SAMGs based on revisions to generic severe accident technical guidelines. Licensees will also ensure that SAMGs are considered within plant configuration management processes. As noted in the NEI letter, the licensee provided a letter (Reference 11.4) to establish a site-specific regulatory commitment for Calvert Cliffs.

In a letter to NEI dated February 23, 2016 (Reference 11.5), the staff outlined its approach for making changes to the ROP in accordance with the Commission direction. The staff engaged NEI and other stakeholders to identify the near-term and long-term changes to the ROP, consistent with the Commission direction and the licensees' near-term and long-term SAMG commitments. The staff then revised Inspection Procedure 71111.18, "Plant Modifications" (Reference 11.6), to provide oversight of the initial inclusion of SAMGs within the plant configuration management processes to ensure that the SAMGs reflect changes to the facility over time.

Multiunit/Multisource Dose Assessments In COMSECY-13-0010, "Schedule and Plans for Tier 2 Order on Emergency Preparedness for Japan Lessons Learned," dated March 27, 2013 (Reference 11.13), the NRC staff requested Commission approval to implement the NTTF recommendation concerning multiunit/multisource dose assessments by having licensees document their commitment to obtain multiunit/multisource dose assessment capability by the end of 2014, rather than by issuing an order. Multiunit dose assessment capabilities would be made generically applicable through subsequent rulemaking. The Commission approved the staff's requests in the SRM to COMSECY-13-0010, dated April 30, 2013 (Reference 11.14). The licensee commitments are documented in References 11.8 through 11.11.

B. Hanson The NRC staff included the multiunit/multisource dose assessment requirement in the proposed MBDBE rulemaking (Reference 11.1 ). However, in response to a public comment concerning the 10 CFR 50.109 backfitting justification for the proposed multiple source term dose assessment requirements, the staff determined that this requirement did not meet the criteria for imposition under 10 CFR 50.109(a)(4)(ii). The NRC staff also concluded that this could not be justified as a compliance backfit or as a substantial safety improvement whose costs, both direct and indirect, would be justified in light of the potential safety gain. Therefore, these requirements were removed from the draft final rule (Reference 11.16).

The licensee provided the requested information and stated that Calvert Cliffs will have multiunit/multisource dose assessment capabilities (Reference 11.11) by December 31, 2014.

The NRC acknowledged the licensee's submittal (Reference 11.12), verified the implementation of these dose assessment capabilities through inspection per Tl 2515/191, and issued an inspection report (Reference 11.15).

CONCLUSION The NRC staff concludes that Exelon, the licensee, has implemented the NRG-mandated safety enhancements resulting from the lessons learned from the Fukushima Dai-ichi accident through its implementation of Orders EA-12-049, EA-12-051, and its response to the 50.54(f) letter at Calvert Cliffs. No further regulatory decisionmaking is required for Calvert Cliffs related to the Fukushima lessons-learned.

A listing of the applicable correspondence related to the Fukushima lessons-learned activities for Calvert Cliffs is included as an enclosure to this letter.

If you have any questions, please contact Robert Bernardo of my staff at 301-415-2621 or by e-mail at Robert.Bernardo@nrc.gov.

Sincerely, cJr~~~4<.J Louise Lund, Director Division of Licensing Projects Office of Nuclear Reactor Regulation Docket Nos. 50-317 and 50-318

Enclosure:

Documents Related to Required

Response

cc w/encl: Distribution via Listserv

Calvert Cliffs Nuclear Power Plant, Units 1 and 2 Reference Documents Related to Required Response to the Lessons Learned from the Fukushima Dai-ichi Accident TABLE 1 Initial Actions in Response to the Events in Japan Caused by the Great Tohoku Earthquake and Subsequent Tsunami

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NRC Information Notice 2011-05 NRC Follow-up to the Fukushima Dai-ichi Fuel Dama e Event March 23, 2011 ML11077A007 NRC Tl 2515/183 Inspection Report May 13, 2011 ML111310243 2011-009 Summa of Observations - Tl-183 November 28, 2011 ML11325A020 1.3 NRC Tasking Memorandum, Staff March 23, 2011 ML110820875 Requirements Memorandum (SRM) to COMGBJ-11-0002 1.4 NRC Availability and Readiness Inspection of SAMG NRC Availability and Readiness April 29, 2011 ML11115A053 Ins ection of SAMG - Tl 2515/184 NRC Integrated Inspection Report July 22, 2011 ML112030196 2011-003 (Tl 2515/184 inspection results NRC Tl 2515/184 Inspection Results, May 27, 2011 ML111470361 Re ion 1 Summa ML11154A109 1.5 NRC Bulletin 2011-01, "Miti ation Strate ies" NRC Bulletin 2011-01 Licensee 30 day response to BL 2011-01 Licensee 60 day response to BL 2011- July 11, 2011 ML11194A023 01 NRC Request for Additional Information November 30, 2011 ML12038A013 (RAI) regarding Licensee 60 day res onse to BL 2011-01 Februa 3, 2012 ML12038A014 NRC Closeout of BL 2011-01 for August 22, 2012 ML12230A115 Calvert Cliffs NRC Correction letter 1.6 NRC NTTF Re ort SECY-11-0093 1.7 NRC SECY-11-0137, Prioritization of Recommended Actions To Be Taken in Res onse to Fukushima Lessons Learned NRC SECY-11-0137 October 3, 2011 ML11272A111 SRM-SECY-11-0137 December 15, 2011 ML113490055 1.8 NRC Order EA-12-049 March 12, 2012 ML12054A735 1 Agencywide Documents Access and Management System (ADAMS)

Enclosure

Calvert Cliffs Nuclear Power Plant, Units 1 and 2 TABLE 1 Initial Actions in Response to the Events in Japan Caused by the Great Tohoku Earth uake and Subse uent Tsunami _,.,.,..,...

1.9 NRC Order EA-12-050 March 12, 2012 ML12054A694 1.10 NRC Order EA-12-051 March 12, 2012 ML12054A679 1.11 NRC Request for Information Under March 12, 2012 ML12053A340 10 CFR 50.5 f the 50.54 f letter 1.12 NRC Order EA-13-109 June 6, 2013 ML13143A321 1.13 NRC SECY-16-0142, "Draft Final Rule: December 15, 2016 ML16301A005 Miti ation of Be ond-Desi n-Basis Events" 1.14 Regulatory Guide 1.226, Flexible Mitigation November 2016 ML16301A128 Strategies for Beyond-Design-Basis Events Draft Final Version 1.15 Regulatory Guide 1.227, Wide Range Spent November 2016 ML16211A167 Fuel Pool Level Instrumentation (Draft Final Version 1.16 Regulatory Guide 1.228 - Integrated Response November 2016 ML16218A236 Capabilities for Beyond-Design-Basis Events Draft Final Version Calvert Cliffs Nuclear Power Plant, Units 1 and 2 TABLE 2 Order to Modify Licenses with Regard to Requirements for Mitigation Strategies for Be ond-Desi n-Basis External Events - EA-12-049 Guidance for Compliance with EA-12-049 -

Diverse and Flexible Co in Strate ies FLEX Industry Guidance on Diverse and December 2015 ML16005A625 Flexible Coping Strategies (FLEX)

NEI 12-06, Revision 2 NRC endorsement of NEI 12-06, January 22, 2016 ML15357A163 Revision 2 - JLD-ISG-2012-01, Revision 1 2.2 Licensee Overall lnte rated Plan OIP Licensee OIP submittal ML13066A171 ML13074A056 ML13254A278 ML14069A318 OIP 3rd six month status re ort ML14241A379 OIP 4th six month status re ort ML15078A117 OIP 5th six month status re ort ML15243A080 OIP 6th six month status re ort ML16057A005 2.3 NRC Interim Staff Evaluation of OIP ML13225A566 2.4 NRC audit of EA-12-049 OIP NRC Notification of Audit of EA-12-049 2.5 Licensee Compliance Letter for EA-12-049 and Final lnte rated Plan FIP Licensee EA-12-049 Compliance Letter July 2, 2015 ML15183A235 for Unit 1 Licensee EA-12-049 Compliance Letter May 4, 2016 ML16131A638 for Unit 2 and FIP 2.6 NRC Safety Evaluation of Implementation of September 29, ML16258A446 EA-12-049 2016

2. 7 NRC Inspection of Licensee Responses to EA-12-049, EA-12-051, and Emergency Pre aredness Information December 23, 2015 ML15257A188 NRC Tl 2515/191 Inspection Report May 30, 2017 ML17151A232 2017-007 2.8 Industry White Paper - National SAFER September 11, ML14259A221 Res onse Centers NSRC 2014 2.9 NRC Staff Assessment of NSRCs September 26, ML14265A107 2014 Calvert Cliffs Nuclear Power Plant, Units 1 and 2 TABLE 2 Order to Modify Licenses with Regard to Requirements for Mitigation Strategies for Be ond-Desi n-Basis External Events - EA-12-049

~~~~~:FPiti~iru-~~-;,-J NRC Inspection of Implementation of EA-12-049 Re ardin the use of NSRC NRC Inspection Procedure (IP) 43006 September 30, ML16273A318 2016 NRC Vendor Inspection of the Phoenix January 12, 2017 ML17012A186 NSRC Re ort No. 99901013/2016-201 NRC Vendor Inspection of the Memphis May 5, 2017 ML17117A576 NSRC Re ort No. 99901013/2017-201 NA NRC approval of relaxation request of the March 4, 2015 ML15054A334 schedule requirements for Order EA-12-049 for Calvert Cliffs Unit 2 (60 days following restart from s rin 2015 refuelin outa e Calvert Cliffs Nuclear Power Plant, Units 1 and 2 TABLE 3 Order to Modify Licenses with Regard to Reliable Spent Fuel Pool Instrumentation -

EA-12-051 Guidance for Compliance with EA-12-051 -

S ent Fuel Pool Instrumentation SFPI Industry Guidance for Compliance with August 2012 ML12240A307 EA-12-051 - NEI 12-02, Revision 1 NRC endorsement of NEI 12-02, August 29, 2012 ML12221A339 Revision 1 - JLD-ISG-2012-03, Revision 0 3.2 Licensee Overall lnte rated Plan OIP Licensee OIP Februa 28,2013 ML13066A172 Licensee OIP su lement March 8, 2013 ML13073A155 OIP 1st six month status re ort Au ust27,2013 ML13254A279 OIP 2nd six month status re ort Februa 24,2014 ML14069A180 OIP 3rd six month status re ort Au ust26, 2014 ML14241A017 OIP 4th six month status re ort Februa 20,2015 ML15057A045 3.3 NRC Interim Staff Evaluation of OIP September 25, ML13267A285 2013 3.4 NRC Audit of EA-12-051 March 26, 2014 ML14083A620 September 15, ML14203A326 2014 ML14210A449 ML14302A174 3.5 Licensee Com liance Letter for EA-12-051 ML15120A277 3.6 NRC Safety Evaluation of Implementation of ML16258A446 EA-12-051 3.7 NRC Inspection of Licensee Responses to EA-12-049, EA-12-051, and Emergency Pre aredness Information NRC Tern ora Instruction 2515/191 December 23, 2015 ML15257A188 NRC Tl 2515/191 Inspection Report May 30, 2017 ML17151A232 2017-007 Note: Table 4 relates to the hardened containment vent system and is not applicable to Calvert Cliffs.

Calvert Cliffs Nuclear Power Plant, Units 1 and 2 TABLE 5 Request for Information Under Title 10 of the Code of Federal Regulations, Section 50.54(f), Enclosure 1: Recommendation 2.1 Seismic Hazard Reevaluation Guidance Documents 5.1 Screening, Prioritization and Implementation Details SPID Industry Guidance (SPID) - November 2012 ML12333A170 EPRI 1025287 NRC letter endorsin SPID Februa 15,2013 ML12319A074 5.2 NRC guidance for performing a Seismic November 16, 2012 ML12286A029 Margin Assessment (SMA) -

JLD-ISG-2012-04 5.3 Expedited Seismic Evaluation Process ESEP Industry Letter - Proposed path April 9, 2013 ML13101A345 forward for NTTF Recommendation 2.1: Seismic Industry Guidance - Expedited April 2013 ML13102A142 Seismic Evaluation Process (ESEP) -

EPRI 3002000704 NRC letter endorsing the ESEP May 7, 2013 ML13106A331 approach. Extension of ESEP due date to 3/31/14 for Central and Eastern U.S. CEUS sites ML13281A308 ML14030A046 5.6 Industry letter on seismic risk evaluations for March 12, 2014 ML14083A596 CEUS lants 5.7 NRC background paper - Probabilistic seismic May 20, 2014 ML14140A648 hazard anal sis 5.8 Licensee Seismic Hazard Screening Report and an su laments 5.9 NRC Staff Assessment of Reevaluated Seismic Hazard Information Screenin and Prioritization Results 5.10 NRC Letter - Seismic screening and May 9, 2014 ML14111A147 rioritization results for CEUS lants 5.11 NRC Letter - Updated seismic screening and October 3, 2014 ML14258A043 rioritization results 5.12 NRC letter regarding development of Seismic December 10, 2014 ML143078707 Risk Evaluations - suitability of updated seismic hazard information for further assessments Calvert Cliffs Nuclear Power Plant, Units 1 and 2 TABLE 5 Request for Information Under Title 10 of the Code of Federal Regulations, Section 50.54(f}, Enclosure 1: Recommendation 2.1 Seismic Hazard Reevaluation ESEP Submittal and Evaluation Licensee ESEP Submittal NRC Response Letter for the ESEP Submittal Additional Guidance Documents 5.14 High Frequency Program Application Guidance Industry HF Application Guidance -

EPRI 3002004396 NRC letter endorsing HF Application Guidance 5.15 S ent Fuel Pool Evaluation Guidance Industry SFP evaluation guidance - February 23, 2016 ML16055A017 EPRI 3002007148 NRC letter endorsing SFP evaluation March 17, 2016 ML15350A158 uidance 5.16 NRC Letter - Treatment of Seismic and September 29, ML15127A401 Flooding Hazard Reevaluations in the Design 2015 and Licensin Basis 5.17 NRC Guidance for Regulatory September 21, ML16237A103 Decisionmaking of reevaluated flooding and 2016 seismic hazards Final Determinations of Required Seismic Evaluations 5.18 NRC Final Determination of Required Seismic Evaluations 5.19 Licensee Required Seismic Evaluation Submittals 5.20 Audit Ian of seismic evaluations submittals 5.21 NRC Staff Assessment of Seismic Evaluations S ent Fuel Pool Evaluation October 12, 2016 Calvert Cliffs Nuclear Power Plant, Units 1 and 2 TABLE 6 Request for Information Under Title 10 of the Code of Federal Regulations, Section 50.54(f), Enclosure 2: Recommendation 2.1 Flooding Hazard Reevaluation Initial Guidance Documents 6.1 NRC prioritization of plants for completing May11,2012 ML12097A509 flood hazard reevaluations 6.2 NRG-issued guidance for performing an November 30, 2012 ML12311A214 integrated assessment for external flooding JLD-ISG-2012-05 6.3 NRC letter to industry describing when an December 3, 2012 ML12326A912 inte rated assessment is ex ected 6.4 NRG-issued guidance for performing a January 4, 2013 ML12314A412 tsunami, surge, or seiche hazard assessment JLD-ISG-2012-06 6.5 NRC letter to industry with guidance on the March 1, 2013 ML13044A561 content of flood in reevaluation submittals 6.6 NRG-issued guidance for assessing flooding July 29, 2013 ML13151A153 hazards due to dam failure JLD-ISG-2013-01 Flood Hazard Reevaluation Report

6. 7 Licensee FHRR Submittal FHRR Submittal March 12, 2013 ML13078A010 Februa 10, 2014 ML14052A052 March 7, 2014 ML14162A261 Amendment to FHRR September 23, ML15272A311 2015 6.8 FHRR Re uests for Additional Information NRC RAI 6.9 NRC Ins ection of licensee interim actions NRC Tl 2515/190, Inspection of August 30, 2013 ML13217A436 proposed interim actions as a result of FHRR NRC Integrated Inspection Report November 4, 2013 ML133098550 2013-004 (Tl 2515/190 inspection results 6.10 NRC Interim Staff Response to Reevaluated October 21, 2015 ML15281A218 Flood Hazards Su lement to FHRR SA 6.11 NRC Staff Assessment of FHRR Modified Approach to Flood Hazard Reevaluations 6.12 NRC extension of due dates for Integrated November 21, 2014 ML14303A465 Assessment re orts 6.13 NRC COMSECY-14-0037, "Integration of November 21, 2014 ML14309A256 Mitigating Strategies for Beyond-Design-Basis External Events and the Reevaluation of Floodin Hazards" 6.14 NRC SRM for COMSECY-14-0037 March 30, 2015 ML15089A236 Calvert Cliffs Nuclear Power Plant, Units 1 and 2 TABLE 6 Request for Information Under Title 10 of the Code of Federal Regulations, Section 50.54(f}, Enclosure 2: Recommendation 2.1 Flooding Hazard Reevaluation

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6.15 NRC letter on second extension of due date May 26, 2015 ML15112A051 for flood in inte rated assessment re orts 6.16 NRC COMSECY-15-0019 "Closure Plan for June 30, 2015 ML15153A104 the Reevaluation of Floodin Hazards" 6.17 NRC SRM-COMSECY-15-0019 Jul 28,2015 ML15209A682 6.18 NRC letter describing the graded approach to September 1, 2015 ML15174A257 flood hazard reevaluation directed by SRM-COMSECY-14-0037 6.19 Floodin Assessment Guidance NEI 16-05, "External Flooding April 2016 ML16165A178 Assessment Guidelines" NRC endorsement of NEI 16 July 11, 2016 ML16162A301 JLD-ISG-2016-01 6.20 Licensee Focused Evaluation Janua 5, 2017 ML17006A158 6.21 NRC Staff Assessment of Focused Evaluation December 20, 2017 ML17338A356 6.22 Jul 18, 2017 ML17192A452 6.23 NRC Letter - Treatment of Seismic and September 29, ML15127A401 Flooding Hazard Reevaluations in the Design 2015 and Licensin Basis 6.24 NRC Guidance for Regulatory Decisionmaking September 21, ML16237A103 of reevaluated floodin and seismic hazards 2016 Calvert Cliffs Nuclear Power Plant, Units 1 and 2

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n.,No.,r 7.1 NRC COMSECY-14-0037, Integration of November 21, 2014 ML14309A256 Mitigating Strategies with Hazard Reevaluations 7.2 NRC SRM-COMSECY-14-0037 March 30, 2015 ML15089A236 7.3 NRC COMSECY-15-0019, Closure Plan for June 30, 2015 ML15153A104 Floodin Hazard Reevaluations 7.4 NRC SRM-COMSECY-15-0019 7.5 Process for Mitigating Strategies Assessments MSA Industry Guidance for performing December 2015 ML16005A625 MSAs - NEI 12-06, Revision 2, includin A endices E, G, & H NRC endorsement of NEI 12-06, January 22, 2016 ML15357A163 Revision 2 - JLD-ISG-2012-01, Revision 1 7.6 Licensee's MSA submittal - Floodin November 9, 2016 ML16314A017 7.7 NRC Staff Assessment of MSA - Floodin December 20, 2017 ML17324B369 7.8 Licensee's MSA submittal - Seismic 7.9 NRC Staff Assessment of MSA - Seismic NRC MSASA ML18033A209 NRC correction to MSA SA ML18040A455 7.10 NRC MSA Audit Plan December 5, 2016 ML16259A189 Calvert Cliffs Nuclear Power Plant, Units 1 and 2 TABLE 8 Request for Information Under Title 10 of the Code of Federal Regulations, Section 50.54 , Enclosure 3: Recommendation 2.3 Seismic Walkdown Industry Seismic Walkdown Guidance with NRC endorsement letter - EPRI 1025286 8.2 NRC letter endorsin EPRI 1025286 8.3 Licensee Seismic Hazard Walkdown November 27, 2012 ML123490409 Re ort Packa e, Unit 1 Licensee Seismic Hazard Walkdown November27,2012 ML123390475 Re ort Packa e, Unit 2 8.4 NRC Ins ection of Seismic Walkdowns NRC Tl 2515/188 NRC Integrated Inspection Report 2012-005 (Tl 2515/188 inspection results 8.5 Subsequent seismic walkdown report, June 12, 2014 ML14169A095 Unit 1 acka e Subsequent seismic walkdown report, June 28, 2013 ML13193A150 Unit 2 8.6 NRC Staff Assessment of Seismic Walkdown June 2, 2014 ML14134A133 Re ort 8.7 NRC review of seismic subsequent walkdown September 25, ML15268A477 re orts 2015 TABLE 9 Request for Information Under Title 10 of the Code of Federal Regulations, Section 50.54 , Enclosure 4: Recommendation 2.3 Floodin Walkdown 9.2 9.3 Update to Flooding Hazard Walkdown Re ort - APM Assessment 9.4 NRC Ins ection of Floodin Walkdowns NRC Tl 2515/187 June 27, 2012 ML12129A108 NRC Integrated Inspection Report February 7, 2013 ML13038A323 2012-005 (Tl 2515/187 inspection results 9.5 NRC Staff Assessment of Flooding Walkdown June 26, 2014 ML141708022 Re ort Calvert Cliffs Nuclear Power Plant, Units 1 and 2 TABLE10 Request for Information Under Title 10 of the Code of Federal Regulations, Section 50.54(f), Enclosure 5: Recommendation 9.3 Emergency Preparedness Communications and Staffin

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Guidance Documents Industry Guidance for May 2012 ML12125A412 Emergency Preparedness staffing and communications -

NEI 12-01 NRC letter endorsin NEI 12-01 Ma 15, 2012 ML12131A043 10.2 Calvert Cliffs 60 day response and May11,2012 ML12136A231 ro osed alternative course of action 10.3 Calvert Cliffs 90 day response to June 8, 2012 ML12165A315 communications and staffing information re uests 10.4 10.5 Licensee communications assessment and im lementation schedule Licensee communications October 26, 2012 ML12311A300 assessment and implementation schedule Licensee supplemental February 22, 2013 ML13066A710 communications assessment information and revision to 10/26/12 assessment submittal Licensee Commitment Chan e October 14, 2014 ML14287A659 10.6 NRC staff assessment of licensee's April 24, 2013 ML13100A240 communications assessment 10.7 Licensee Phase 1 staffin assessment A ril 26, 2013 ML13120A111 10.8 NRC Phase 1 staff assessment October 23, 2013 ML13233A183 res onse 10.9 Licensee Phase 2 staffing assessment res onse Licensee Phase 2 staffing October 13, 2014 ML14293A077 assessment for functions related to miti atin strate ies Licensee res onse to RAI March 30, 2015 ML15089A256 Licensee supplemental response May 5, 2015 ML15131A215 to RAI 10.10 NRC Phase 2 staff assessment September 9, 2015 ML15231A029 res onse 10.11 NRC Inspection of Licensee Responses to EA-12-049, EA-12-051, and Erner enc Pre aredness Information NRC Temporary Instruction December 23, ML15257A188 2515/191 2015 NRC Tl 2515/191 Inspection May 30, 2017 ML17151A232 Re ort 2017-007 Calvert Cliffs Nuclear Power Plant, Units 1 and 2 TABLE 11 Additional Licensee Commitments - SAMGs and Multisource Dose Assessments 11.1 SECY-15-0065: Proposed Rulemaking: April 30, 2015 ML15049A201 Mitigation of Beyond-Design-Basis Events RIN 3150-AJ49 11.2 SRM-SECY-15-0065 Au ust27,2015 ML15239A767 11.3 NEI Letter describing industry initiative October 26, 2015 ML15335A442 to u date and maintain SAMGs 11.4 Site commitment to maintain SAMGs December 4, 2015 ML15338A125 11.5 NRC letter to NEI describing approach February 23, 2016 ML16032A029 to SAMG oversi ht 11.6 NRC Inspection Procedure 71111.18, November 17, ML16306A185 "Plant Modifications" 2016 11.7 NEI 14-01, "Emergency Response February 2016 ML16224A619 Procedures and Guidelines for Extreme Events and Severe Accidents, Rev. 1 Multisource Dose Assessments 11.8 NEI Letter: Industry survey and plan for January 28, 2013 ML13028A200 multiunit dose assessments 11.9 NRC Letter to request additional February 27, 2013 ML13029A632 information from NEI on multiunit dose assessment ca abilit 11.10 NEI Letter: Commitment for March 14, 2013 ML13073A522 Implementation of Multiunit Dose Assessment Ca abilit 11.11 Licensee Response Regarding the June 21, 2013 ML13175A362 Capability to Perform Multisource Offsite Dose Assessment 11.12 NRC Acknowledgement of Licensee January 29, 2014 ML13233A205 Dose Assessment Submittals 11.13 COMSECY-13-0010 11.14 SRM-COMSECY-13-0010 11.15 NRC Inspection of Licensee Responses to EA-12-049, EA-12-051, and Erner enc Pre aredness Information NRC Temporary Instruction December 23, ML15257A188 2515/191 2015 NRC Tl 2515/191 Inspection May 30, 2017 ML17151A232 Re ort 2017-007 11.16 Draft Final Rule: Mitigation of December 15, ML16301A005 Beyond-Design-Basis Events 2016 SECY-16-0142, Packa e 11.17 NEI 13-06, "Enhancements to February 2016 ML16224A618 Emergency Reponses Capabilities for Beyond Design Basis Accidents and Events, Revision 1 Calvert Cliffs Nuclear Power Plant, Units 1 and 2 NRC Semi-Annual Status Re orts to the Commission 12.1 SECY-12-0025, Enclosure 8, "Proposed February 17, 2012 ML12039A103 Orders and Requests for Information in Response to Lessons Learned from Japan's March 11, 2011, Great Tohoku Earthquake and Tsunami" 12.2 SECY-12-0095 - Enclosure 1: Six-Month July 13, 2012 ML12165A092 Status Update On Charter Activities -

Februa 2012-Jul 2012 12.3 SECY-13-0020 - Third 6-Month Status Update February 14, 2013 ML13031A512 On Response To Lessons Learned From Japan's March 11, 2011, Great Tohoku Earth uake And Subse uent Tsunami 12.4 SECY-13-0095 - Fourth 6-Month Status September 6, 2013 ML13213A304 Update on Response to Lessons Learned from Japan's March 11, 2011, Great Tohoku Earth uake and Subse uent Tsunami 12.5 SECY-14-0046 - Fifth 6-Month Status Update April 17, 2014 ML14064A520 on Response to Lessons Learned From Japan's March 11, 2011, Great Tohoku Earth uake and Subse uent Tsunami 12.6 SECY-14-0114 - Sixth 6-Month Status Update October 21, 2014 ML14234A498 on Response to Lessons Learned from Japan's March 11, 2011, Great Tohoku Earth uake and Subse uent Tsunami 12.7 SECY-15-0059 - Seventh 6-Month Status April 9, 2015 ML15069A444 Update on Response to Lessons Learned from Japan's March 11, 2011, Great Tohoku Earth uake and Subse uent Tsunami 12.8 SECY-15-0128: Eighth 6-Month Status October 14, 2015 ML15245A473 Update on Response to Lessons Learned from Japan's March 11, 2011, Great Tohoku Earth uake and Subse uent Tsunami 12.9 SECY-16-0043: Ninth 6 Month Status Update April 5, 2016 ML16054A255 on Response to Lessons Learned from Japan's March 11, 2011, Great Tohoku Earth uake and Subse uent Tsunami 12.10 SECY-17-0016: Status of Implementation of January 30, 2017 ML16356A084 Lessons Learned from Japan's March 11, 2011, Great Tohoku Earthquake and Subse uent Tsunami

ML18071A197 *Via e-mail OFFICE NRR/DLP/PBEB/PM NRR/DLP/PBMB/LA NRR/DLP/PBEB/BC(A)*

NAME RBernardo SLent TBrown DATE 3/20/18 3/20/18 3/23/18 OFFICE NRR/DLP/PBMB/BC(A)* NRR/DLP/D  : ':**,

NAME EBowman LLund t: "'.0/

DATE 3/21/18 3/28/18 }1,;