ML17254A042

Report for the Audits of Licensee Responses of Order EA-13-109 to Modify Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions (CAC Nos. MF4479 and

ML17254A042
Person / Time
Site:	Hatch
Issue date:	09/19/2017
From:	Rajender Auluck Japan Lessons-Learned Division
To:	Hutto J Southern Nuclear Operating Co
Auluck R, NRR/JLD, 415-1025
References
CAC MF4479, CAC MF4480, EA-13-109
Download: ML17254A042 (19)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 September 19, 2017 Mr. James J. Hutto Regulatory Affairs Director Southern Nuclear Operating Co., Inc.

P.O. Box 1295, Bin 038 Birmingham, AL 35201-1295

SUBJECT:

EDWIN I. HATCH NUCLEAR PLANT, UNITS 1 AND 2 - REPORT FOR THE AUDIT OF LICENSEE RESPONSES TO INTERIM STAFF EVALUATION OPEN ITEMS RELATED TO NRG ORDER EA-13-109 TO MODIFY LICENSES WITH REGARD TO RELIABLE HARDENED CONTAINMENT VENTS CAPABLE OF OPERATION UNDER SEVERE ACCIDENT CONDITIONS (CAC NOS. MF4479 AND MF4480)

Dear Mr. Hutto:

On June 6, 2013 (Agencywide Documents Access and Management System (ADAMS)

Accession No. ML13143A334), the U.S. Nuclear Regulatory Commission (NRG) issued Order EA-13-109, "Order to Modify Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Condition," to all Boiling Water Reactor (BWR) licenses with Mark I and Mark II primary containments. The order requirements are provided in to the order and are divided into two parts to allow for a phased approach to implementation. The order required licensees to submit for review overall integrated plans (OIPs) that describe how compliance with the requirements for both phases of Order EA-13-109 will be achieved.

By letter dated June 27, 2014 (ADAMS Accession No. ML14178B464), Southern Nuclear Operating Company, Inc. (SNC, the licensee) submitted its Phase 1 OIP for Edwin I. Hatch Nuclear Plant, Units 1 and 2 (Hatch). By letters dated December 30, 2014, June 26, 2015, December 23, 2015 (which included the combined Phase 1 and Phase 2 OIP), June 13, 2016, December 14, 2016, and June 12, 2017 (ADAMS Accession Nos. ML15049A513, ML15177A353, ML15357A212, ML16165A184, ML16349A160 and ML17163A224, respectively) , the licensee submitted its 6-month updates to the OIP. The staff reviewed the information provided by the licensee and issued interim staff evaluations (ISEs) for Phase 1 and Phase 2 of Order EA-13-109 for Hatch by letters dated March 25, 2015 (ADAMS Accession No. ML14335A137), and August 2, 2016 (ADAMS Accession No. ML16099A260), respectively.

When developing the ISEs, the staff identified open items where the staff needed additional information to determine whether the licensee's plans would adequately meet the requirements of Order EA-13-109.

The NRG staff is using the audit process described in the letters dated May 27, 2014 (ADAMS Accession No. ML14126A545), and August 10, 2017 (ADAMS Accession No. ML17220A328),

to gain a better understanding of licensee activities as they come into compliance with the order.

As part of the audit process, the staff reviewed the licensee's closeout of the ISE open items.

The NRG staff conducted teleconferences with the licensee on March 8, 201 7, and August 15, 2017. The enclosed audit report provides a summary of that aspect of the audit.

J. Hutto If you have any questions, please contact me at 301-415-1025 or by e-mail at Rajender.Auluck@nrc.gov.

Sincerely, Rajender Auluck, Senior Project Manager Containment and Balance of Plant Branch Japan Lessons-Learned Division Office of Nuclear Reactor Regulation Docket Nos.: 50-321 and 50-366

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 AUDIT OF LICENSEE RESPONSES TO INTERIM STAFF EVALUATION OPEN ITEMS RELATED TO ORDER EA-13-109 MODIFYING LICENSES WITH REGARD TO RELIABLE HARDENED CONTAINMENT VENTS CAPABLE OF OPERATION UNDER SEVERE ACCIDENT CONDITIONS SOUTHERN NUCLEAR COMPANY, INC.

EDWIN I. HATCH NUCLEAR PLANT. UNITS 1 AND 2 DOCKET NOS. 50-321AND50-326 BACKGROUND On June 6, 2013 (Agencywide Documents Access and Management System (ADAMS)

Accession No. ML13143A334), the U.S. Nuclear Regulatory Commission (NRG) issued Order EA-13-109, "Order to Modify Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Condition," to all Boiling Water Reactor (BWR) licenses with Mark I and Mark II primary containments. The order requirements are divided into two parts to allow for a phased approach to implementation.

Phase 1 of Order EA-13-109 requires license holders of BWRs with Mark I and Mark 11 primary containments to design and install a Hardened Containment Vent System (HCVS), using a vent path from the containment wetwell to remove decay heat, vent the containment atmosphere (including steam, hydrogen, carbon monoxide, non-condensable gases, aerosols, and fission products), and control containment pressure within acceptable limits. The HCVS shall be designed for those accident conditions (before and after core damage) for which containment venting is relied upon to reduce the probability of containment failure, including accident sequences that result in the loss of active containment heat removal capability or extended loss of alternating current power. The order required all applicable licensees, by June 30, 2014, to submit to the Commission for review an overall integrated plan (OIP) that describes how compliance with the Phase 1 requirements described in Order EA-13-109 Attachment 2 will be achieved.

Phase 2 of Order EA-13-109 requires license holders of BWRs with Mark I and Mark II primary containments to design and install a system that provides venting capability from the containment drywell under severe accident conditions, or, alternatively, to develop and implement a reliable containment venting strategy that makes it unlikely that a licensee would need to vent from the containment drywell during severe accident conditions. The order required all applicable licensees, by December 31 , 2015, to submit to the Commission for review an OIP Enclosure

that describes how compliance with the Phase 2 requirements described in Order EA-13-109 will be achieved .

By letter dated June 27, 2014 (ADAMS Accession No. ML14178B464), Southern Nuclear Operating Company, Inc. (SNC, the licensee) submitted its Phase 1 OIP for Edwin I. Hatch Nuclear Plant, Units 1 and 2 (Hatch, HNP) , in response to Order EA-13-109. By letters dated December 30, 2014, June 26, 2015, December 23, 2015 (which included the combined Phase 1 and Phase 2 OIP) , June 13, 2016, December 14, 2016 and June 12, 2017 (ADAMS Accession Nos. ML15049A513, ML15177A353, ML15357A212, ML16165A184, ML16349A160 and ML17163A224, respectively) , the licensee submitted its 6-month updates to the OIP, as required by the order.

The staff reviewed the information provided by the licensee and issued interim staff evaluations (ISEs) for Phase 1 and Phase 2 for Hatch by letters dated March 25, 2015 (ADAMS Accession No. ML14335A137), and August 2, 2016 (ADAMS Accession No. ML16099A260), respectively.

When developing the ISEs, the staff identified open items where the staff needed additional information to determine whether the licensee's plans would adequately meet the requirements of Order EA-13-109.

The NRG staff is using the audit process in accordance with the letters dated May 27, 2014, (ADAMS Accession No. ML14126A545), and August 10, 2017 (ADAMS Accession No. ML17220A328), to gain a better understanding of licensee activities as they come into compliance with the order. The staff reviews submitted information, licensee documents (via ePortals), and preliminary Overall Program Documents (OPDs)/OIPs, while identifying areas where additional information is needed. As part of this process, the staff reviewed the licensee closeout of the ISE open items.

AUDIT

SUMMARY

As part of the audit, the NRG staff conducted teleconferences with the licensee on March 8, 2017, and August 15, 2017. The purpose of the audit teleconferences was to continue the audit review and provide the NRG staff the opportunity to engage with the licensee regarding the closure of open items from the ISEs. As part of the preparation for these audit calls , the staff reviewed the information and/or references noted in the OIP updates to ensure that closure of ISE open items and the HCVS design are consistent with the guidance provided in NEI 13-02, Rev. 1 and related documents (e.g. white papers (WPs) and frequently asked questions (FAQs)) that were developed and reviewed as part of overall guidance development. The NRG staff audit members are listed in Table 1. Table 2 is a list of documents reviewed by the staff.

Table 3 provides the status of the ISE open item closeout for Hatch. The open items are taken from the Phase 1 and Phase 2 ISEs that were issued on March 25, 2015 (ADAMS Accession No. ML14335A137), and August 2, 2016 (ADAMS Accession No. ML16099A260), respectively.

FOLLOW UP ACTIVITY The staff continues to audit the licensee's information as it becomes available. The staff will issue further audit reports for Hatch , as appropriate.

Following the licensee's declarations of order compliance, the licensee will provide a final integrated plan (FIP) that describes how the order requirements are met. The NRG staff will evaluate the FIPs , the resulting site-specific OPDs, as appropriate , and other licensee documents, prior to making a safety determination regarding order compliance .

CONCLUSION This audit report documents the staff's understanding of the licensee's closeout of the ISE open items, based on the documents discussed above. The staff notes that several of these documents are still preliminary, and all documents are subject to change in accordance with the licensee's design process. In summary, the staff has no further questions on how the licensee has addressed the ISE open items, based on the preliminary information. The status of the NRC staff 's review of these open items may change if the licensee changes its plans as part of final implementation . Changes in the NRC staff review will be communicated in the ongoing audit process.

Attachments:

1. Table 1 - NRC Staff Audit and Teleconference Participants

2. Table 2 - Audit Documents Reviewed

3. Table 3 - ISE Open Item Status Table

Table 1 - NRC Staff Audit and Teleconference Participants Title Team Member Organization T earn Lead/Project Manaqer Raiender Auluck NRR/JLD Project Manager Support/Technical Support - Containment I Ventilation Brian Lee NRR/JLD Technical Support - Containment I Ventilation Bruce Heida NRR/JLD Technical Support - Electrical Kerby Scales NRR/JLD Technical Support - Balance of Plant Kevin Roche NRR/JLD Technical Support - l&C Steve Wyman NRR/JLD Technical Support - Dose John Parillo NRR/DRA Attachment 1

Table 2 - Audit Documents Reviewed Calculation SMNH-13-013, "Sizing of Accumlator Tanks for Reliable Hardened Containment Vent System" Calculation SMNH-13-019, "Sizing of Nitrogen Bottles for Reliable Hardened Containment Venting System" FSAR, Section 8.4, "Stanby AC Power Supply" NEDC-32749P, "Entended Power Uprate Safety Analysis Report for Edwin I. Hatch Units 1 and 2"

GE MDE-03-0186, "Safe Shutdown Appendix R Analysis for Edwin I. Hatch Nuclear Power Station Units 1 and 2" Calculation SENH-13-005, "Load Data for Sizing the Inverters for FLEX and HCVS" Calculation SENH-16-003, "Battery Sizing, Voltage Drop, Cable Sizing, and Short Circuit Evaluation for 250V Dedicated Battery System" Calculation A-47402, "FLEX DG Sizing" Calculation DOEJ-HDSNC598056-M001 , "Identification of Boundary and Control Valves Required to Prevent Hydrogen Migration for the Unit 2 Hardened Containment Vent System (HCVS)"

Calculation DOEJ-HDSNC598056-M003, "Hardened Containment Vent System (HCVS) Control of Flammable Gases" Calculation SMNH-13-023, "Hydrogen Crossflow in Mixing Chamber" Procedure NMP-OS-019-013, "Beyond Design Basis Equipment Unavailablilty Tracking" Procedure OS-019-013-GL02, "Hatch BOB Equipment Unavailablitly Tracking Guideline" BWROG-TP-008, "Severe Accident Water Addition Timing" BWROG-TP-011 , "Severe Accident Water Management Supporting Evaluations" Attachment 2

Hatch Nuclear Station Vent Order Interim Staff Evaluation Open Items:

Table 3 - ISE Open Item Status Table ISE Open Item Number Licensee Response - Information NRC Staff Close-out notes SE status provided in 6-month updates and on Closed; Pending; Open Requested Action the ePortal (need info from licensee)

Phase 1 ISE 01 1 Included on page 16 of 66 in the Phase 1 The NRC staff reviewed the Closed and Phase 2 OIP: information provided in the 6-Make available for NRC staff month updates. [Staff evaluation to be audit the location of the "The final location of the ROS [Remote included in safety evaluation ROS's. Operating Station] is the 147' elevation of The ROS is in a location that is (SE) Section 3.1.2.4]

the Control Building, one floor below the readily accessible and appears to elevation of the MCR [main control support operation of the HCVS.

room] ."

No follow-up questions.

Phase 1 ISE 01 2 Included on page 13 of 66 in the Phase 1 The NRC staff reviewed the Closed and Phase 2 OIP: information provided in the 6-Make available for NRC staff month updates. [Staff evaluation to be audit the location of the "Access to the transfer switch is located included in SE Section dedicated HCVS battery on the ground elevation of the Control The battery transfer switch is 3.1.2.6]

transfer switch. Building." located on the ground elevation of the Control Building and is readily accessible and appears to support operation of the HCVS.

No follow-up questions.

Phase 1 ISE 01 3 Included on page 13 of 66 in the Phase 1 The NRC staff reviewed the Closed and Phase 2 OIP: information provided in the six-Make available for NRC staff month updates and on the ePortal. [Staff evaluation to be audit documentation of the "Nitrogen bottles will be located in the included in SE Section HCVS nitrogen pneumatic Control Building." First 24-hour operation is from 3.1.2.6]

system design including installed air accumulator tanks.

sizing and location. After 24-hours pneumatic motive Attachment 3

Calculations for the accumulator tank and force can be provided by nitrogen nitrogen bottle sizing are included in tanks.

SMNH-13-013 and SMNH-13-019.

Calculation SMNH-13-013 estimated the compressed gas requirements and sized air accumulators for 8 air-operated valves (AOVs) associated with the HCVS for the first 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. The calculation assumed seven valves open and remain open with air pressure. The 81h valve was assumed to cycle 12 times.

System leakage was assumed to be 0.4 scfh based on the worst case solenoid valve air leakage or 9.6 set over 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. This appears to be sufficient to provide the required number of valve manipulations.

Calculation SMNH-13-019 determined the nitrogen bottle requirements to provide motive force back-up for the HCVS AOVs.

Calculation uses the resu lts of calculation SMNH-13-013.

No follow-up questions.

Phase 1 ISE 01 4 Two portable diesel generators (PDGs) The NRC staff reviewed the Closed will be located on the west side of the information on the deployment Make available for NRC staff Control Building for Unit 1. One portable location of the PDGs provided in [Staff evaluation to be audit the deployment diesel generator will be located on the the 6-month updates. included in SE Section location of the portable south side of the Turbine Building for Unit 3.1.2.6) diesel generators. 2 and one DG will be located at the base The licensee has three portable of Main Stack. FLEX DGs (600 Vac, 545 kW). Two FLEX DGs that will be staged on the west side of the Control Building for Unit 1. One FLEX DG will be staqed on the

south side of the Turbine Building for Unit 2. The licensee also has one portable DG (600 Vac, 85 kW )

that will be staged at the base of main stack to repower the stack mixing chamber fans and some of the interconnecting valves.

These locations for the deployment of the PDGs are in mild temperature and low dose areas ,

which support plant personnel accessibility for the operation of the HCVS.

No follow-up questions .

Phase 1 ISE 01 5 Included on page 16 of 66 in the Phase 1 The NRC staff reviewed the Closed and Phase 2 OIP ... information provided in the 6-Make available for NRC staff month updates . [Staff evaluation to be audit an evaluation of "The HCVS design allows initiating and included in SE Sections temperature and radiological then operating and monitoring the HCVS The licensee stated that the ROS 3.1 .1 .2 and 3.1 .1 .3]

conditions to ensure that from the Main Control Room (MGR) or the is located at grade level and is operating personnel can Remote Operating Station (ROS). The open to the outdoors. The safely access and operate MCA location is protected from adverse licensee indicated they had controls and support natural phenomena and is the normal procedures and equipment to equipment. control point for HCVS operation and permit operator use of the ROS Plant Emergency Response actions." during cold weather.

The final location of the ROS is the 147' Temperatures do not exceed 11 O elevation of the Control Building , one floor degrees farenheit (F°), which is below the elevation of the MCA. acceptable for long-term personnel Additional support equipment is located habitability. Radiological on the 130' elevation (ground elevation) of conditions result in low operator the Control Building (battery throw-over dose.

switch and nitrogen bottle rack).

No follow-up questions.

The licensee references site-specific assumption HNP-5 from the OIP, which described the Control Building having substantial structural walls and features

independent of the Reactor Bu ilding.

Also, the licensee references HCVS-FAQ-08, HCVS-FA0-04, and GDC19.

Phase 1 ISE 01 6 The suppression pool is capable of The NRC staff reviewed the Closed accepting operation of the reactor core information provided in the 6-Make available for NRC staff isolation cooling system and safety relief month updates and on the ePortal. [Staff evaluation to be audit analyses valvess without any suppression pool included in SE Section demonstrating that HCVS cooling during the station blackout (SBO) In response to staff question 3.1.2.1) has the capacity to vent the cooling duration. Although not required, regarding HCVS capacity, the steam/energy equivalent of suppression pool cooling capability can licensee indicated that the one percent of be initiated within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> when the evaluation in FLEX NEDC 33771 P, licensed/rated thermal power alternating current (ac) source becomes "GEH Evaluation of FLEX (unless a lower value is available by meeting the diesel loading Implementation Guidelines," is a justified), and that the margins. (Reference Section 8.4 of the FLEX OIP reference. This suppression pool and the Final Safety Analysis report) document was reviewed du ring the HCVS together are able to FLEX audits. This document absorb and reject decay The current containment and Reactor determined that a 12-inch vent heat, such that following a Pressure Vessel thermal hydraulic provided adequate venting. Per reactor shutdown from full analysis for SBO took credit for analysis OIP page 15 "The size of the power containment pressure performed for 10 CFR 50 1 , Appendix R wetwell portion of the HCVS is ~18 is restored and then (fire protection). As part of the extended inches in diameter which provides maintained below the power uprate, the SBO scenario was adequate capacity to meet or primary containment design reanalyzed assuming that suppression exceed the Order criteria." The pressure and the primary pool cooling was initiated in 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> when stack mixing chamber and stack containment pressure limit. the alternate ac is assumed available. pipe is ~ 1 8 inches, thus based on The peak pool temperature is 167 °F. the NEDC assessment of a 12-Even if SPC is not initiated until 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />, inch vent, the HNP vent (~ 1 8 the resulting peak pool temperature of inches) is adequate 194 °F is acceptable for containment and ECCS pump operation. (Reference No follow-up questions.

NEDC- 32749P, "Extended Power Uprate Safety Analysis Report for Edwin I. Hatch Units 1 and 2", July 1997 and GE MDE-03-0186 "Safe Shutdown Appendix R Analysis for Edwin I. Hatch Nuclear Power Station Units 1 and 2")

1 Title 1O of the Code of Federal Regulations, Part 50

GE MDE-03-0186 on ePortal. Addresses Unit 1 and Unit 2.

Phase 1 ISE 01 7 The original design for the Generic Letter The NRC staff reviewed the Closed (GL) 89-16 vent line was 345 °F, so information provided in the 6-Make available for NRC staff engineering judgement was used for month updates. [Staff evaluation to be audit the descriptions of qualification to 350 °F based on included in SE Section local conditions downstream cool ing of vent piping . The licensee has described an 3.1.1.4)

(temperature, radiation and acceptable approach for qualifying humidity) anticipated during Specification for new equipment and the components (valves, extended loss of ac power instrumentation included environmental instrumentation , sensors, (ELAP) and severe accident conditions expected from licensee for transmitters , indicators, for the components (valves , post-accident design values. electronics , control devices , and instrumentation, sensors, etc.) needed for the operation of transmitters, indicators, New equipment procured to comply with the HCVS for ELAP and severe electronics , control devices , the Order was purchased through new accident conditions.

and etc.) required for HCVS specifications the ROS , batteries, and venting including battery charger. Those specifications No follow-up questions.

confirmation that the contain all the required operating components are capable of parameters for the equipment for normal performing their functions operation , design-basis accidents, as well during ELAP and severe as beyond-design-basis external event accident conditions. (BDBEE) requirements. The radiation monitor is an "off the shelf" monitor without its own specification. It was procured with a datasheet specific to Hatch for radiation and temperature requirements.

Each item procured with a specification requires test reports be provided that the test specimens performed in compliance with the specification requirements . The radiation monitor also has multiple test reports which document compliance with required operating conditions/parameter.

Other commodities such as condu it, wiring, piping , etc. were procured cons istent with the design requ irements of the systems and locations they were

being installed. For example, items installed in the control building - non-harsh environment with temperatu re considerations consistent with current SBO temperatures and radiation. These other items like pipe, cable, valves ,

transmitters were procured AO as necessary to meet the BDBEE requirements for the location where they are installed. The majority of equipment installed is located outside the reactor building , and therefore does not require additional qualification beyond normal operatinq/accident conditions of the plant.

Phase 1 ISE 01 8 The licensee provided : The NRC staff reviewed the Closed information provided in the 6-Make available for NRC staff Calculation SENH-13-003. month updates and on the ePortal. [Staff evaluation to be audit the final sizing included in SE Section evaluation for HCVS Modification Calculation SENH-16-003. The NRC staff reviewed licensee 3.1.2.6) batteries/battery charger calculation SENH-16-003, "Battery including incorporation into FLEX DG Sizing Calculation A-47402 . Sizing , Voltage Drop, Cable Sizing ,

FLEX DG loading and Short Circuit Evaluation for calculation . 250V Dedicated Battery System (Unit 2) ," Version 2, which verified the capability of the existing Class 1E batteries supplemented with the new Division 1 and 2 batteries to extend the battery capacity to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of operation for HCVS functions. The NRC staff also reviewed the separation and isolation of the new HCVS batteries from the Class 1E batteries. The NRC staff reviewed calculation A-47402, "FLEX Portable System Phase 2 600V FLEX Diesel Generation Sizing Calculation," Version 1 and the separation and isolation of the FLEX DGs from the EDGs. Based

on the NRC staff's review, the required loads for the Phase 2 600 Vac, 545 kW FLEX DG total approximately 387 kW for both units' Division I loads and 383 kW for both units' Division II loads. This also takes into account the HCVS loads.

No follow-up questions.

Phase 1 ISE 01 9 Notifications can be made with either the The NRC staff reviewed the Closed gaitronics system or via runners to the information provided in the six-Make available for NRC staff MCR or ROS to allow operation of the month updates and on the ePortal. [Staff evaluation to be audit documentation that HCVS once the portable DGs are included in SE Section demonstrates adequate operating . The communication methods are 3.1.1.1]

communication between the the same as accepted in Order remote HCVS operation EA-12-049.

locations and HCVS decision makers during No follow-up questions.

ELAP and severe accident conditions.

Phase 1 ISE 01 10 Included on page 17 of 66 in the Phase 1 The NRC staff reviewed the Closed and 2 OIP ... information provided in the 6-Provide a description of the month updates and on the ePortal. [Staff evaluation to be final design of the HCVS to "Plant Hatch plans to use option 1 of the included in SE Section address hydrogen endorsed white paper HCVS-WP-03 and DOEJ-HDSNC598056-M003 3.1 .2.11]

detonation and deflagration. power up the mixing chamber fan in the (Documentation of Engineering base of the meteorological stack." Judgment) addresses HCVS Control of Flammable Gases. The In addition , Hatch plans to close HCVS licensee's design is consistent with boundary valves and main stack option 1 of the endorsed white interconnecting valves and purge the paper HCVS-WP-03.

main stack mixing chamber. Hatch will utilize a portable diesel generator No follow-up questions.

deployed to the stack to repower the stack mixing chamber fans and power operators on some of the interconnecting valves .

See Calculations DOEJ-HDSNC598056-M003 and SMNH-13-023. Both on ePortal.

Phase 1 ISE 01 11 Refer to response to ISE open item #10 The NRC staff reviewed the Closed and leakage testing of boundary valves information provided in the 6-Provide a description of the found in calculations in DOEJ M003 and month updates and on the ePortal. [Staff evaluation to be strategies for hydrogen SMNH-13-023. included in SE Section control that minimizes the DOEJ-HDSNC598056-M003 3.1.2.1 2]

potential for hydrogen gas (Documentation of Engineering migration and ingress into Judgment) addresses HCVS the reactor building or other Control of Flammable Gases, buildings. which appears to maintain hydrogen below flammability limits.

SMNH-13-023 addresses H2 infiltration into Main Stack gas mixing chamber.

No follow-uo auestions.

Phase 1 ISE 01 12 The HCVS interface to other systems is The NRC staff reviewed the Closed described in Section 2, pages 1O and 17 information provided in the 6-Make available descriptions of 66 in the Phase 1 and 2 OIP. month updates and on the ePortal. [Staff evaluation to be of details that minimize included in SE Section unintended cross flow of The boundary valves will be tested in Licensee strategy appears to 3.1.2.3]

vented fluids within a unit accordance with the guidance of NEI 13- minimize unintended cross flow.

and between units. 02, FAO-HCVS-05 to ensure unintended system cross flow is minimized. No follow-up questions.

Refer to the response to ISE item #10 and leakage testing of 10 boundary valves per the LLRT program procedure 42SV-TET-001 -2. Details are in Calculations DOEJ M003 and SMNH 023.

DOEJ-HDSNC598056-M003 and SMNH-13-023. Both on ePortal.

Phase 1 ISE 01 13 Refer to DCP 598056 ILOM for l&C The NRC staff reviewed the Closed components (l&C and electrical information provided in the 6-Make available for NRC staff sections) .. . month updates and on the ePortal.

audit descriotions of all

instrumentation and controls "Demonstration that instrumentation is Instrumentation appears sufficient [Staff evaluation to be (existing and planned) substantially similar to the design of to monitor and control HCVS included in SE Section necessary to implement this instrumentation previously qualified ." operation . Qualification standards 3.1.2.8]

order including qualification are industry-accepted for th is type methods. Site design standards such as Institute of of application .

Electrical and Electron ics Engineers (IEEE) 323-1974 or IEEE 324-1975 were No follow-up questions.

used in the specifications.

Phase 1 ISE 01 14 Existing primary containmet isolation The NRC staff reviewed the Closed valves (PCIVs) that perform a design- information provided in the 6-Make available for NRC staff basis function were utilized . Per NEI 13- month updates and on the ePortal. [Staff evaluation to be audit documentation of an 02 no further evaluation is required . included in SE Section 3.2.1]

evaluation verifying the No follow-up questions.

existing containment The expected differential is within the isolation valves, relied upon scope of containment design for for the HCVS, will open compliance with GL 89-16 since under the maximum containment pressure is managed below expected differential the design pressure.

pressure during BDBEE and severe accident wetwell Additionally, Hatch is utilizing existing venting . PCIVs which were designed and procured to meet the containment design pressures.

Phase 1 ISE 01 15 Procedures NMP-OS-019-013 and NMP- The NRC staff reviewed the Closed OS-019-013-GL02 were provided on the information provided in the 6-Make available for NRC staff eportal for NRC review. month updates and on the ePortal. [Staff evaluation to be audit the control document included in SE Section for HCVS out of service time No follow-up questions. 3.1.2.13]

criteria.

Phase 2 ISE 01 1 The wetwell vent has been designed and The NRC staff reviewed the Closed installed to meet NEI 13-02 Rev 1 information provided in the 6-Licensee to demonstrate guidance which will ensure that it is month updates and on the ePortal. [Staff evaluation to be that containment failure as a adequately sized to prevent containment included in SE Sections 4.1 result of overpressure can overpressure under severe accident BWR Owners Group (BWROG)- and 4.2]

be prevented without a conditions . TP-008 demonstrates adding drywell vent during severe water to the reactor vessel within accident conditions Section The severe accident water management 8-hours of the onset of the event 3.3.3 (SAWM) strateqy will ensure that the will limit the peak containment

wetwell vent remains functional for the drywell temperature significantly period of sustained operation . HNP will reducing the possibility of follow the guidance (flow rate and timing ) containment failure due to for SAWA/SAWM described in BWROG- temperature. Drywell pressure can TP-15-008 and BWROG-TP-15-011 . be controlled by venting the suppression chamber through the These documents have been posted to suppression pool.

the ePortal for NRC staff review . The wetwell vent will be opened prior to BWROG-TP-011 demonstrates exceeding the PCPL value of 62 per that starting water addition at a square inch gauge. Therefore, high rate of flow and throttling after containment over pressurization is approximately 4-hours will not prevented without the need for a drywell increase the suppression pool vent. level to that which could block the suppression chamber HCVS.

As noted under Phase 1, the vent is sized to pass a minimum steam flow equivalent to 1% rated core power. This is sufficient to permit venting to maintain containment below the lower of Primary Containment Pressure Limit (PCPL) or of design pressure.

No follow-up questions.

Phase 2 ISE 01 2 Using Figure 2.1.C from the combined The NRC staff reviewed the Closed Phase 1 and 2 OIP, compare the information provided in the 6-Licensee shall demonstrate reference plant parameters to the plant month updates and on the ePortal. [Staff evaluation to be how the plant is bounded by specific parameters . included in SE Section the reference plant analysis Staff reviewed the parameters 4.2.1.1]

that shows the SAWM Reference Plant rHNP from the reference plant to those of Torus lreeboard volume Torus lreeboard strategy is successful in 1s 525,00'gallons Ivolume is >805.161 2 Hatch. Staff concur that it is making it unlikely that a I . gallons unlikely the suppression chamber

• SAWA flow is 500 GPM I SAWA ftow is 500 drywell vent is needed at 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> followed by GPM at 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> HCVS could become blocked .

Section 3.3.3.1 I j 100 GPM from 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> followed by 100 GPM Therefore, it is unlikely a drywell to 168 hours0.00194 days <br />0.0467 hours <br />2.777778e-4 weeks <br />6.3924e-5 months <br /> from 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> to 168 hours0.00194 days <br />0.0467 hours <br />2.777778e-4 weeks <br />6.3924e-5 months <br /> vent would be required to maintain containment integrity.

The above parameters for HNP demonstrate that the reference plant No follow-up questions.

values are bounding. Therefore, the SAWM strategy implemented at HNP makes it unlikely that a drywall vent is needed to prevent containment overpressure related failure .

Phase 2 ISE 01 3 HNP utilizes gaitronics paging system or The NRC staff reviewed the Closed runners to communicate between the information provided in the 6-Licensee to demonstrate MCR and the Intake Structure operator at month updates and on the ePortal. [Staff evaluation to be that there is adequate the FLEX pump. This communication included in SE Section 4.1]

communication between the method is the same as accepted in Order The communication methods are MCR and the Intake EA-12-049. Gaitronics has been modified the same as accepted in Order Structure operator at the with a 12-hour Uniterruptible Power EA-12-049.

FLEX manual valve during Supply battery backup and will be severe accident conditions. repowered with FLEX portable DGs. No follow-up questions.

Section 3.3.3.4

ML17254A042 *via e-mail OFFICE NRR/JLD/JCBB/PM NRR/JLD/LA NRR/JLD/JCBB/BC(A) NRR/JLD/JCBB/PM NAME RAuluck Slent SBailey RAuluck DATE 09/18/201 7 09/12/201 7 09/18/2017 09/19/201 7