ML16006A213

Report for the Onsite Audit Regarding Implementation of Mitigating Strategies Related to Order EA-12-049

ML16006A213
Person / Time
Site:	Nine Mile Point
Issue date:	02/04/2016
From:	Jason Paige Japan Lessons-Learned Division
To:	Bryan Hanson Exelon Generation Co
Paige, Jason NRR/JLD 415-5888
References
CAC MF1130, EA-12-049
Download: ML16006A213 (15)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 February 4, 2016 Mr. Bryan C. Hanson President and Chief Nuclear Officer Exelon Generation Company, LLC 4300 Winfield Rd Warrenville, IL 60555

SUBJECT:

NINE MILE POINT NUCLEAR STATION, UNIT 2 - REPORT FOR THE ONSITE AUDIT REGARDING IMPLEMENTATION OF MITIGATING STRATEGIES RELATED TO ORDER EA-12-049 (CAC NO. MF1130)

Dear Mr. Hanson:

On March 12, 2012, the U.S. Nuclear Regulatory Commission (NRC) issued Order EA-12-049, "Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond Design-Basis External Events" (Agencywide Documents Access and Management System (ADAMS) Accession No. ML12054A736). The order requires holders of operating reactor licenses and construction permits issued under Title 10 of the Code of Federal Regulations Part 50 to submit for review an Overall Integrated Plan. (OIP) including descriptions of how compliance with the requirements of Attachment 2 of the order will be achieved.

By letter dated February 28, 2013 (ADAMS Accession No. ML13066A171), Exelon Generation Company, LLC, previously as Constellation Energy Nuclear Group, LLC (Exelon, the licensee) submitted its OIP for Nine Mile Point Nuclear Station, Units 1 and 2 (NMP), in response to Order EA-12-049. By letter dated March 8, 2013 (ADAMS Accession No. ML13074A056), Exelon submitted a complete revision of the OIP for NMP. By letters dated August 27, 2013, February 27, 2014, August 26, 2014, February 19, 2015, and August 28, 2015 (ADAMS Accession Nos.

ML13254A278, ML14069A318, ML14241A380, ML15062A036, and ML15243A085, respectively), the licensee submitted its first five six-month updates to the OIP. By letter dated August 28, 2013 (ADAMS Accession No. ML13234A503), the NRC notified all licensees and construction permit holders that the staff is conducting audits of their responses to Order EA-12-049 in accordance with NRC Office of Nuclear Reactor Regulation (NRR) Instruction LIC-111, "Regulatory Audits" (ADAMS Accession No. ML082900195). This audit process led to the issuance of the NMP interim staff evaluation (ISE) and audit report (ADAMS Accession No. ML13225A584) and continues with in-office and onsite portions of this audit.

The ongoing audits allow the staff to review open and confirmatory items from the mitigation strategies ISE, the licensee's integrated plans, and other audit questions. Additionally, the staff gains a better understanding of submitted and updated information, audit information provided on ePortals, and preliminary Overall Program Documents/Final integrated Plans while identifying additional information necessary for the licensee to supplement its plan and staff potential concerns.

The staff conducted an onsite audit at NMP from November 3-7, 2014, in accordance with the audit plan dated October 8, 2014 (ADAMS Accession No. ML14274A288). Due to the different strategies and technologies between the units, the staff focused its review on Unit 1, since its

B. Hanson compliance date is prior to Unit 2. As stated in the October 8, 2014, audit plan, onsite audits for subsequent units at a site will be on an as-needed basis. By letter dated April 28, 2015 (ADAMS Accession No. ML 1511 OA026), the staff issued an audit report for the November 3-7, 2014, onsite audit.

As a follow-up to focus on.the Unit 2 strategy, the NRC staff conducted a second onsite audit at NMP from November 16-20, 2015, per the audit plan dated October 20, 2015 (ADAMS Accession No. ML15289A526). The purpose of the onsite portion of the audit was to provide the NRC staff the opportunity to continue the audit review and gain key insights most easily obtained at the plant as to whether the licensee is on the correct path for compliance with the Mitigation Strategies order. The onsite activities included detailed analysis and calculation discussion, walk-throughs of strategies and equipment laydown, visualization of portable equipment storage and deployment, and staging and deployment of offsite equipment.

The enclosed audit report provides a summary of the activities for the onsite audit portion.

Additionally, this report contains an attachment listing all open audit items currently under NRC staff review.

If you have any questions, please contact me at 301-415-5888 or by e-mail at Jason.Paige@nrc.gov.

Jason Paige, Project Manager Orders Management Branch Japan Lessons-Learned Division Office of Nuclear Reactor Regulation Docket No.: 50-410

Enclosure:

Audit Report cc w/encl: Distribution via Listserv

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 AUDIT REPORT BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO ORDER EA-12-049 MODIFYING LICENSES WITH REGARD TO REQUIREMENTS FOR MITIGATION STRATEGIES FOR BEYOND-DESIGN-BASIS EXTERNAL EVENTS EXELON GENERATION COMPANY. LLC NINE MILE POINT NUCLEAR STATION. UNIT 2 DOCKET NO. 50-410 BACKGROUND AND AUDIT BASIS On March 12, 2012, the U.S. Nuclear Regulatory Commission (NRC) issued Order EA-12-049, "Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond Design-Basis External Events" (Agencywide Documents Access and Management System (ADAMS) Accession No. ML12054A736). The order requires holders of operating reactor licenses and construction permits issued under Title 10 of the Code of Federal Regulations Part 50 to submit for review an Overall Integrated Plan (OIP) including descriptions of how compliance with the requirements of Attachment 2 of the order will be achieved.

By letter dated February 28, 2013 (ADAMS Accession No. ML13066A171 ), Exelon Generation Company, LLC, previously as Constellation Energy Nuclear Group, LLC (Exelon, the licensee) submitted its OIP for Nine Mile Point Nuclear Station, Units 1 and 2 (NMP), in response to Order EA-12-049. By letter dated March 8, 2013 (ADAMS Accession No. ML13074A056), Exelon submitted a complete revision of the OIP for NMP. By letters dated August 27, 2013, February 27, 2014, August 26, 2014, February 19, 2015, and August 28, 2015 (ADAMS Accession Nos.

ML13254A278, ML14069A318, ML14241A380, ML15062A036, and ML15243A085, respectively), the licensee submitted its first five six-month updates to the OIP. By letter dated August 28, 2013 (ADAMS Accession No. ML13234A503), the NRC notified all licensees and construction permit holders that the staff is conducting audits of their responses to Order EA-12-049 in accordance with NRC Office of Nuclear Reactor Regulation (NRR) Instruction LIC-111, "Regulatory Audits" (ADAMS Accession No. ML082900195). This audit process led to the issuance of the NMP interim staff evaluation (ISE) and audit report (ADAMS Accession No. ML13225A584) and continues with in-office and onsite portions of this audit.

The ongoing audits allow the staff to review open and confirmatory items from the mitigation strategies ISE, the licensee's integrated plans, and other audit questions. Additionally, the staff gains a better understanding of submitted and updated information, audit information provided on ePortals, and preliminary Overall Program Documents (OPDs)/Final Integrated Plans (FIPs)

Enclosure

while identifying additional information necessary for the licensee to supplement its plan and staff potential concerns.

The staff conducted an onsite audit at NMP from November 3-7, 2014, in accordance with the audit plan dated October 8, 2014 (ADAMS Accession No. ML14274A288). Due to the different strategies and technologies between the units, the staff focused its review on Unit 1, since its compliance date is prior to Unit 2. As stated in the October 8, 2014, audit plan, onsite audits for subsequent units at a site will be on an as-needed basis. By letter dated April 28, 2015 (ADAMS Accession No. ML 1511 OA026), the staff issued an audit report for the November 3-7, 2014, onsite audit.

As a follow-up to focus on the Unit 2 strategy, the NRC staff conducted a second onsite audit at NMP from November 16-20, 2015, per the audit plan dated October 20, 2015 (ADAMS Accession No. ML15289A526). The purpose of the onsite portion of the audit was to provide the NRC staff the opportunity to continue the audit review and gain key insights most easily obtained at the plant as to whether the licensee is on the correct path for compliance with the Mitigation Strategies order. The onsite activities included detailed analysis and calculation discussion, walk-throughs of strategies and equipment laydown, visualization of portable equipment storage and deployment, and staging and deployment of offsite equipment.

Following the licensee's declarations of order compliance, the NRC staff will evaluate the OIPs, as supplemented, the resulting site-specific OPDs/FIPs, and, as appropriate, other licensee submittals based on the requirements in the order. The staff will make a safety determination regarding Order EA-12-049 compliance using the Nuclear Energy Institute (NEI) guidance document NEI 12-06, "Diverse and Flexible Coping Strategies (FLEX) Implementation Guide" issued in August, 2012 (ADAMS Accession No. ML12242A378), as endorsed by NRC Japan Lessons-Learned Directorate (JLD) interim staff guidance (ISG) 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'" (ADAMS Accession No. ML12229A174),

as providing one acceptable means of meeting the order requirements. Should the licensee propose an alternative strategy or other method deviating from the guidance, additional staff review will be required to evaluate if the alternative strategy complies with the order.

AUDIT ACTIVITIES The onsite audit was conducted at the NMP facility from November 16, 2015, through November 19, 2015. The NRC audit team staff was as follows:

Title Team Member T earn Lead/Project Manager Jason Paige Technical Support Michael Levine Technical Support Matthew McConnell Technical Support Brett Titus Technical Support Laura Okruhlik

The NRC staff executed the onsite portion of the audit per the three part approach discussed in the October 20, 2015, plan, to include conducting a tabletop discussion of the site's integrated mitigating strategies compliance program, a review of specific technical review items, and discussion of specific program topics. Activities that were planned to support the above included detailed analysis and calculation discussions, walk-throughs of strategies and equipment laydown, visualization of portable equipment storage and deployment, and staging and deployment of offsite equipment.

AUDIT

SUMMARY

1.0 Entrance Meeting (November 16. 2015)

At the audit entrance meeting, the NRC staff audit team introduced itself followed by introductions from the licensee's staff. The NRC audit team provided a brief overview of the audit's objectives and anticipated schedule.

2.0 Integrated Mitigating Strategies Compliance Program Overview Per the audit plan and as an introduction to the site's program, the licensee provided a presentation to the NRC audit team titled "Nine Mile Point Nuclear Station Unit 2 FLEX NRC Audit Orientation." The licensee provided an overview of its mitigating strategies in the event of a beyond-design-basis external event, and the plant modifications being done in order to implement the strategies. Also presented was the design and location of the FLEX equipment storage facility, the FLEX equipment that would be stored there, and the interface with the National SAFER Response Center (NSRC).

3.0 Onsite Audit Technical Discussion Topics Based on the audit plan, and with a particular emphasis on the Part 2, "Specific Technical Review Items," the NRC staff technical reviewers conducted interviews with licensee technical staff, site walk-downs, and detailed document review for the items listed in the plan. Results of these technical reviews that require additional information from the licensee are documented in the audit item status table in Attachment 3, as discussed in the Conclusion section below.

3. 1 Reactor Systems Technical Discussions and Walk-Downs The NRC staff reviewed NMP2 modeling of an extended loss of alternating current power event (ELAP) and its ability to mitigate the event, including the computer code Modular Accident Analysis Program (MAAP) used and input parameters assumed to generate the results of the analysis. The licensee noted that the MAAP analysis was carried out in accordance with EPRI 3002001785, "Use of Modular Accident Analysis Program (MAAP) in Support of Post-Fukushima Applications," dated June 2013. In addition, the licensee indicated that Electric Power Research Institute (EPRI) later released the boiling water reactor (BWR) roadmap EPRI 3002002749, "Technical Basis for Establishing Success Timelines in Extended Loss of AC Power Scenarios in Boiling

Water Reactors Using MAAP4." The licensee followed the BWR template for NMP2, however, no NMP2 specific benchmarks were created due to the generic benchmarks in the BWR template bounding NMP2.

3.2 Electrical Technical Discussions and Walk-Downs The NRC staff reviewed the calculations on extending battery life based on load shedding, calculations on sizing for the FLEX diesel generators (DG), and walked down the switchgear, direct current (DC) equipment, and battery rooms to evaluate strategies for hydrogen and temperature control. The licensee will begin the NMP2 load shed at the beginning of the ELAP event and plans to load shed in two increments, one within 60 minutes and the second within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />, which will provide a maximum coping time using the batteries of 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. The licensee plans to have the Phase 2 FLEX generators deployed and supplying power to the battery chargers at approximately 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> from the start of the ELAP event. The licensee has (3) 450 kW, 563 KVA Phase 2 FLEX generators stored in the FLEX storage building. The licensee noted that the total calculated power demand for the FLEX generators is less than the generator rating of 563 KVA. In addition to the 450 kW generators, the licensee has (6) 900 W generators in the FLEX storage building that will be used for communications equipment such as charging radio batteries and portable satellite phone batteries. To support Phase 3, NMP2 will receive (3) generators, two 4160 voltage alternating current (VAC) generators and one 480 VAC generator including a step-up transformer, from NSRC.

3.3 Other Technical Discussion Areas and Walk-Downs

a. The NRC staff reviewed the licensee's plan for sharing facility resources between units.

The staff's review focused on the identification of any shared resources and the management of those resources during an ELAP. The licensee stated that the two units will share FLEX resources for debris removal, towing, refueling, FLEX storage, and offsite communications. The licensee stated that deployment strategies include expected priority for equipment. The licensee no longer plans to share the dry hydrants from one unit to the other. The licensee stated that the dry hydrants are no longer planned for NMP1 and that the dry hydrant design for NMP2 is not presently expected to be sized to accommodate the combined flow for NMP1 and NMP2.

b. The NRC staff reviewed the battery room ventilation strategy to prevent hydrogen accumulation while recharging the batteries during Phase 2 or 3. The licensee stated that the normal battery room HVAC exhaust configuration is expected to remain unchanged for the ELAP condition. NMP2 plans to re-power the existing installed battery room ventilation fans, since these fans are normally energized from the emergency buses and the FLEX strategy is to re-power a 600 VAC emergency bus.

c. The NRC staff reviewed the need for heat tracing to protect against freezing of piping, instrument lines, and equipment. The licensee stated that no equipment or instrumentation used in the NMP2 FLEX strategies will require the use of heat tracing.

d. The NRC staff reviewed the licensee's calculations to demonstrate that the NMP2 containment functions will be restored and maintained following an ELAP event. The licensee provided the staff with several MAAP calculations which showed the response of the containment to various operations of the vent at different times. For example, one calculation "without venting" was used to determine the minimum time available before the reactor core isolation cooling (RCIC) pump operation would be challenged. The staff noted that the "no venting" timeline is very conservative and likely not indicative of how the operators would be controlling the plant during an ELAP. The licensee concluded that they have MAAP calculations which demonstrate that containment parameters will be maintained under a number of venting scenarios; however, a single MAAP run has not been identified to substantiate a specific sequence of events timeline. The staff communicated to the licensee that it is expected that a specific MAAP run will be identified in the final integrated plan.

e. The NRC staff reviewed calculations and procedures for venting the refueling floor spent fuel pool (SFP) area to mitigate steam and condensation. The licensee noted that their calculations conclude that when the compensatory actions specified in the procedures are taken, the maximum temperature in the SFP area is approximately 180°F. All of the actions are directed to be taken before 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> when the temperature is less than 120°F.

No actions are anticipated to be needed after 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />. Additionally, the licensee stated that there would be no access to the refueling floor after 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. During the audit, the staff noticed an action to install plastic sheeting to act as a vapor barrier. This action was stated "as needed" in the calculation, but was not specified in any of the referenced procedures. The licensee generated an action report to revise the procedural guidance to include the above action in the NMP2 SFP venting strategy.

f. During the onsite portion of the audit, the licensee provided an evaluation of the RCIC equipment survivability. The evaluation contained an analysis of the impact of exceeding the Updated Final Safety Analysis Report design temperature of 212°F in the suppression pool. Under the most limiting containment conditions, the temperature of the suppression pool was determined to reach 280 degrees °F (no anticipatory venting).

The acceptability of this condition was largely based on comparison to an existing Individual Plant Examination (IPE) evaluation, which considered the ultimate capacity/performance of the containment under more severe conditions of 400°F and 120 psig. Under the IPE conditions, the licensee concluded that the containment demonstrated a very low likelihood of failure. Thus, the licensee concluded that under the less severe FLEX conditions, the likelihood of containment failure is substantially lower. The licensee justified their conclusion by noting that there is an absence of a large pressure load due to the vent being open.

4.0 Exit Meeting (November 19. 2015)

The NRC staff audit team conducted an exit meeting with the licensee staff following the closure of onsite audit activities. The NRC staff highlighted items reviewed and noted that the results of the onsite audit trip will be documented in this report. The following

items that require additional information from the licensee or still under NRC review were discussed at the exit meeting (see Attachments 3 and 4 for additional information):

a. ISE Cl 3.2.4.2.A, Ventilation and Environmental Qualification (EQ)

During the onsite audit, the licensee indicated that they are in the process of finalizing NMP2 calculations to support the ventilation and cooling strategy. For example, the licensee plans on repowering the control room fans using the FLEX DGs, but the licensee still needs to verify that the DGs can support the loads. A second example is that the licensee has to complete an EQ analysis of the solenoids on the safety relief valves (SRVs) to ensure that they can withstand the harsh environment during the ELAP event. The staff requested that the licensee make available the calculations (emergency switchgear room, main control room, battery rooms, etc.) to support the ventilation strategy. After the conclusion of the onsite audit, the licensee made available the requested information. The staff is currently reviewing the information.

b. AQ 20, Reactor Coolant System (RCS) Makeup The licensee noted that NMP2 is relying on RCIC for Phase 1 and transition to using portable FLEX pumps taking suction from the safety-related intake structure, which contains raw water. However, the licensee currently does not have any plans to request a water filtration unit from the NSRC. The NRC staff had a number of questions regarding NMP2 being able to indefinitely cope using raw water (e.g.,

particulates in the water preventing proper heat transfer to cool the core). The NRC staff requested that the licensee make available the NMP2 justification to indefinitely cope using raw water.

CONCLUSION The NRC staff completed all three parts of the October 20, 2015, onsite audit plan. Each audit item listed in Part 2 of the plan was reviewed by NRC staff members while on site. In addition to the list of NRC and licensee onsite audit staff participants in Attachment 1, Attachment 2 provides a list of documents reviewed during the onsite audit portion.

In support of the continuing audit process as the licensee proceeds towards orders compliance for this site, Attachments 3 and 4 provide the status of all open audit review items that the NRC staff is evaluating in anticipation of issuance of a combined safety evaluation (SE) for both the Mitigation Strategies (MS) and Spent Fuel Pool Level Instrumentation orders. The four sources for the audit items referenced below are as follows:

a. Interim Staff Evaluation (ISE) Open Items (Ols) and Confirmatory Items (Cls)

b. Audit Questions (AQs)

c. Licensee-identified Overall Integrated Plan (OIP) Open Items (Ols)

d. Additional Safety Evaluation (SE) needed information

The attachments provide audit information as follows:

a. Attachment 1: List of NRG staff and licensee staff audit participants

b. Attachment 2: List of documents reviewed during the onsite audit

c. Attachment 3: NMP2 MS SE Audit Items currently under NRG staff review and requiring licensee input as delineated

d. Attachment 4: NMP2 MS SE Audit Items currently under NRG staff review but not requiring further licensee input While this report notes the completion of the onsite portion of the audit per the audit plan dated October 20, 2015, the ongoing audit process continues as per the letters dated August 28, 2013, and March 26, 2014, to all licensees and construction permit holders for both orders.

Additionally, while Attachments 3 and 4 provide a progress snapshot of the NRG staff's review of the licensee's OIPs, as supplemented, and as augmented in the audit process, the status and progress of the NRG staff's review may change based on licensee plan changes, resolution of generic issues, and other NRG staff concerns not previously documented. Changes in the NRG staff review will be communicated in the ongoing audit process.

Lastly, the licensee has identified open items that need to be completed to implement Order EA-12-049, and the staff expects that the licensee will continue to provide updates on the status of the licensee identified open items in their 6-month updates or on the ePortal.

Attachments:

1. NRG and Licensee Staff Onsite Audit Participants

2. Onsite Audit Documents Reviewed

3. NMP2 MS SE Audit Items currently under NRG staff review and requiring licensee input

4. NMP2 MS SE Audit Items currently under NRG staff review but not requiring further licensee input

Onsite Audit Participants NRC Staff:

Jason Paige NRR/JLD/JOMB Brett Titus NRR/JLD/JCBB Michael Levine NRR/JLD/JCBB Laura Okruhlik NRR/JLD/JERB Matthew McConnell NRR/JLD/JERB NMP Staff:

Pete Orphanos Site Vice President Alex Sterio Director, Engineering Todd Fiorenza Manager, Project Management Kathy Picciott Director, Fukushima Project (NMP)

George Wrobel Director, Fukushima Project (Ginna)

Dan Cifonelli Operations

.George Inch Engineering Roy Corieri Engineering Mohamed Khan Engineering Josh Rocks Engineering Michael Conway Fukushima Project Dan Morley Engineering Brandon Varga Regulatory Assurance Joanne Johnson Manager, Supply Chain Bill Piccirilli Long Island Power Authority Anthony Mattessich Long Island Power Authority Attachment 1

Documents Reviewed

• Calculation ES-289, Reactor Building Thermal Response Following an Extended Loss of AC Power, Revision 0

• Evaluation 2015-01099, RCIC Equipment Survivability Review, Revision 0

• Calculation ES-198, Control Building Station Blackout Analysis, Revision 1

• Calculation HVC-083, Temperature Evaluation in NMP2 Emergency Switchgear Room during ELAP, Revision 0

• Calculation 2EQDP-SOV011, Environmental Qualification Document Package for Solenoid Coil, Revision 1

• Special Operating Procedure N2-SOP-03, Loss of AC Power, Revision 01400

• Calculation 600VACDGES-FLEX-BDB, Fukushima 600VAC FLEX-BDB-450KW/563KVA, Revision 00.00 (preliminary)

• Calculation ECP-13-00101068, 600VAC FLEX Phase II Portable 450kW Diesel Generator Sizing Calculation, Revision 000

• Document N2-DRP-FLEX-ELEC, Emergency Damage Repair - BOB/FLEX Generator Deployment Strategy, Revision 000-00

• Calculation A 10.1-A-016, Hydraulic Analysis of NMP2 FLEX Water Makeup to the RPV and the SFP, Revision O

• Procedure N2-DPR-FLEX-MECH, Emergency Damage Repair-BOB/FLEX Pump Deployment Strategy, Revision O

• Procedure N2-SOP-02, Station Blackout Support Procedure

• Procedure N2-DRP-OPS-001, Emergency Damage Repair

• Calculation TB-BATT-2014-04, NCN Model Battery Life and Performance at Elevated Accident Environment- Exelon - Nine Mile Point NS, dated November 6, 2014

• Document ER-M-200, Preventive Maintenance Program, Revision 1

• Document S-PM-003, FLEX 450KW Portable Diesel Generator Test, Rev. 00100 Attachment 2

NMP2 Mitigation Strategies Safety Evaluation Audit Items:

Audit Items Currently Under NRC Staff Review And Requiring Licensee Input Audit Item Item Description Licensee Input Needed Reference The licensee noted that NMP2 is relying on RCIC for Phase 1 and transition to using portable FLEX pumps taking suction from the safety-related intake structure, which is raw water. However, the licensee currently does not have any plans on requesting for a water filtration unit from NSRC.

AQ20 RCS makeup The NRC staff had a number of questions regarding NMP2 being able to indefinitely cope using raw water (e.g., particulates in the water preventing proper heat transfer to cool the core). The NRC staff requested that the licensee make available the NMP2 justification to indefinitely cope using raw water.

Attachment 3

NMP2 Mitigation Strategies Safety Evaluation Audit Items:

Audit Items Currently Under NRC Staff Review But Not Requiring Further Licensee Input Audit Item Item Description Action Reference During the onsite audit, the licensee indicated that they are in the process of finalizing NMP2 calculations to support the ventilation and cooling strategy. For example, the licensee plans on repowering the control room fans using the FLEX DGs but the licensee still needs to verify that the DGs can support the loads. A second example is that the licensee has to complete an environmental qualification analysis of the solenoids on the SRVs ISE Cl 3.2.4.2.A Ventilation and EQ to ensure that they can withstand the harsh environment during the ELAP event. The staff requested that the licensee make available the calculations (Emergency Switchgear Room, Main Control Room, Battery Rooms, etc.) to support the ventilation strategy. After the conclusion of the onsite audit, the licensee made available the requested information. The staff is currently reviewing the information.

Attachment 4

ML15110A026), the staff issued an audit report for the November 3-7, 2014, onsite audit.

As a follow-up to focus on the Unit 2 strategy, the NRC staff conducted a second onsite audit at NMP from November 16-20, 2015 per the audit plan dated October 20, 2015 (ADAMS Accession No. ML15289A526). The purpose of the onsite portion of the audit was to provide the NRC staff the opportunity to continue the audit review and gain key insights most easily obtained at the plant as to whether the licensee is on the correct path for compliance with the Mitigation Strategies order. The onsite activities included detailed analysis and calculation discussion, walk-throughs of strategies and equipment laydown, visualization of portable equipment storage and deployment, and staging and deployment of offsite equipment.

The enclosed audit report provides a summary of the activities for the onsite audit portion.

Additionally, this report contains an attachment listing all open audit items currently under NRC staff review.

If you have any questions, please contact me at 301-415-5888 or by e-mail at Jason.Paige@nrc.gov.

Sincerely, IRA John Hughey Acting for/

Jason Paige, Project Manager Orders Management Branch Japan Lessons-Learned Division Office of Nuclear Reactor Regulation Docket No.: 50-410

Enclosure:

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