ML18057B298
| ML18057B298 | |
| Person / Time | |
|---|---|
| Site: | Duane Arnold  |
| Issue date: | 03/05/2018 |
| From: | Auluck R C Beyond-Design-Basis Engineering Branch |
| To: | Dean Curtland Nextera Energy |
| Lee B E | |
| References | |
| CAC MF4391, EA-13-109, EPID L-2014-JLD-0039 | |
| Download: ML18057B298 (20) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 March 5, 2018 Mr. Dean Curtland Site Director NextEra Energy Duane Arnold Energy Center 3277 DAEC Road Palo, IA 52324-9785
SUBJECT:
DUANE ARNOLD ENERGY CENTER -REPORT FOR THE AUDIT OF LICENSEE RESPONSES TO INTERIM STAFF EVALUATIONS OPEN ITEMS RELATED TO NRC ORDER EA-13-109 TO MODIFY LICENSES WITH REGARD TO RELIABLE HARDENED CONTAINMENT VENTS CAPABLE OF OPERATION UNDER SEVERE ACCIDENT CONDITIONS (CAC NO. MF4391; EPID L-2014-JLD-0039)
Dear Mr. Curtland:
On June 6, 2013 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML 13143A334), the U.S. Nuclear Regulatory Commission (NRC) 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 licensees with Mark I and Mark II primary containments.
The order requirements are provided in Attachment 2 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 25, 2014 (ADAMS Accession No. ML 14182A423), NextEra Energy Duane Arnold, LLC (NextEra, the licensee) submitted its Phase 1 OIP for Duane Arnold Energy Center (DAEC, Duane Arnold). By letters dated December 10, 2014, June 18, 2015, December 22, 2015 (which included the combined Phase 1 and Phase 2 OIP), June 30, 2016, December 22, 2016, June 29, 2017, and December 19, 2017 (ADAMS Accession Nos. ML 14349A324, ML15170A333, ML15358A043, ML16187A261, ML16362A211, ML17180A217, and ML 17353A668, respectively), the licensee submitted its 6-month updates to the OIP. The NRC staff reviewed the information provided by the licensee and issued interim staff evaluations ( IS Es) for Phase 1 and Phase 2 of Order EA-13-109 for Duane Arnold by letters dated February 11, 2015 (ADAMS Accession No. ML 15006A319), and September 13, 2016 (ADAMS Accession No. ML 16248A001
), 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.
D. Curtland The NRC staff is using the audit process described in letters dated May 27, 2014 (ADAMS Accession No. ML 14126A545), and August 10, 2017 (ADAMS Accession No. ML 17220A328}, 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 NRC staff conducted teleconferences with the licensee on June 29, 2017, and February 8, 2018, respectively.
The enclosed audit report provides a summary of that aspect of the audit. If you have any questions, please contact me at 301-415-1025 or by e-mail at Rajender.Auluck@nrc.gov.
Docket No. 50-331
Enclosure:
Audit report cc w/encl: Distribution via Listserv Sincerely, Rajender Auluck, Senior Project Manager Beyond-Design-Basis Engineering Branch Division of Licensing Projects Office of Nuclear Reactor Regulation 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 EVALUATIONS OPEN ITEMS RELATED TO ORDER EA-13-109 MODIFYING LICENSES WITH REGARD TO RELIABLE HARDENED CONTAINMENT VENTS CAPABLE OF OPERATION UNDER SEVERE ACCIDENT CONDITIONS NEXTERA ENERGY DUANE ARNOLD, LLC DUANE ARNOLD ENERGY CENTER DOCKET NO. 50-331 BACKGROUND On June 6, 2013 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML 13143A334), the U.S. Nuclear Regulatory Commission (NRC) 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) licensees 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 II 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 (ac) power (ELAP). 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 Enclosure review an OIP that describes how compliance with the Phase 2 requirements described in Order EA-13-109 Attachment 2 will be achieved.
By letter dated June 25, 2014 (ADAMS Accession No. ML 14182A423), NextEra Energy Duane Arnold, LLC (NextEra, the licensee) submitted its Phase 1 OIP for Duane Arnold Energy Center (DAEC, Duane Arnold). By letters dated December 10, 2014, June 18, 2015, December 22, 2015 (which included the combined Phase 1 and Phase 2 OIP), June 30, 2016, December 22, 2016, June 29, 2017, and December 19, 2017 (ADAMS Accession Nos. ML 14349A324, ML 15170A333, ML 15358A043, ML 16187 A261, ML 16362A211, ML 17180A217, and ML 17353A668, respectively), the licensee submitted its 6-month updates to the OIP, as required by the order. The NRC 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 Duane Arnold by letters dated February 11, 2015 (ADAMS Accession No. ML 15006A319), and September 13, 2016 (ADAMS Accession No. ML 16248A001), 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 NRC staff is using the audit process in accordance with the letters dated May 27, 2014 (ADAMS Accession No. ML 14126A545), and August 10, 2017 (ADAMS Accession No. ML 17220A328), 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 NRC staff conducted teleconferences with the licensee on June 29, 2017 and February 8, 2018. The purpose of the audit teleconference was to continue the audit review and provide the NRC staff the opportunity to engage with the licensee regarding the closure of open items from the IS Es. 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 Nuclear Energy Institute (NEI) 13-02, Revision 1 and related documents (e.g. white papers (ADAMS Accession Nos. ML 14126A374, ML 14358A040, ML 15040A038 and ML 15240A072, respectively) and frequently asked questions (FAQs), (ADAMS Accession No. ML 15271 A 148) that were developed and reviewed as part of overall guidance development.
The NRC 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 Duane Arnold. The open items are taken from the Phase 1 and Phase 2 ISEs issued on February 11, 2015, and September 13, 2016, 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 Duane Arnold, 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 NRC 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 Oraanization Team Lead/Sr. Project Manaqer Raiender Auluck NRR/DLP Project Manager Support/Technical Support -Containment/
Ventilation Brian Lee NRR/DLP Technical Support-Containment/
Ventilation Bruce Heida NRR/DLP Technical Support -Electrical Kerbv Scales NRR/DLP Technical Suooort-Balance of Plant Kevin Roche NRR/DLP Technical Support-l&C Steve Wyman NRR/DLP Technical Support -Dose John Parillo NRR/DRA Attachment 1
Table 2 -Audit Documents Reviewed Design Change Package EC -281991, Revision 22 EVAL-16-M18, "Reactor Building Environmental Analysis for FLEX," Revision 0 CAL-M15-013, "Duane Arnold Energy Center Hardened Containment Vent System Pipe Sizing Analysis," Revision 0 CAL-M15-014, "Nitrogen Supply for the Hardened Vent," Revision 0 Procedure SEP 301.3 -Torus Vent Via Hardpipe Vent EVAL-16-C01, "Reasonable Assurance of Protection for HCVS Piping from Failure of Reactor Building Stair #6 Masonary Walls above Elevation 855'," Revision O CAL-R15-002, "Duane Arnold Energy Center Hardened Containment Vent System Dose Assessment," Revision 0 CAL-M15-004, "Hardened Containment Vent System (HCVS) Valve MEDP Evaluation," Revision 0 CAL-M15-003, "Piping Stress Analysis for Hardened Containment Vent System," Revision 0 CAL-E15-002, "125VDC HCVS Battery Charger Sizing and Voltage Drop Calculation," Revision 0 CAL-E13-001, "FLEX Electrical Equipment Sizing," Revision 0 EVAL-16-M01, "Determination of Suppression Pool Volume at Specific Water Levels to Support Severe Accident Water Management (SAWM) Strategies," Revision 0 CAL-M17-001, "Severe Accident Water Addition Piping Analysis, 4" GBB-4 and GBD-70," Revision NI CAL-M15-014, "Nitrogen Supply for the Hardened Vent," Revision 0 BWROG-TP-008, "Severe Accident Water Addition Timing" BWROG-TP-011, "Severe Accident Water Management Supporting Evaluations" Attachment 2
Duane Arnold Energy Center Vent Order Interim Staff Evaluation Open Items: Table 3 -ISE Open Item Status Table ISE Open Item Number Licensee Response -Information NRG Staff Close-out notes Safety Evaluation (SE) provided in 6 month updates and on the status Requested Action ePortal Closed; Pending; Open (need additional information from licensee)
Phase 1 ISE 01 1 The DAEC final design of the HCVS The NRG staff reviewed the Closed utilizes an installed rupture disk. information provided in the 6-Make available for NRG staff month updates and on the [Staff evaluation to be audit documentation of Procedures for rupturing the disk have ePortal. included in SE Section licensee confirmation that been developed for use during beyond 3.1.2.2] secondary containment design bases conditions.
The licensee's HCVS design leakage is acceptable without includes the installation of a an installed rupture disk or that Procedure SEP301 .3 is available for NRG rupture disk, including procedural an appropriate rupture disk, review on the ePortal. guidance for rupture during HCVS including procedures for operation.
rupture during HCVS operation is included in the HCVS No follow-up questions.
design. Phase 1 ISE 01 2 DAEC has completed analysis, CAL-M15-The NRG staff reviewed the Closed 013, when demonstrating the HCVS has information provided in the 6-Make available for NRG staff the capacity to vent the steam/energy month updates and on the [Staff evaluation to be audit analyses demonstrating equivalent to one percent of licensed ePortal. included in SE Section that HCVS has the capacity to thermal power and that the suppression 3.1.2.1] vent the steam/energy pool and HCVS together are able to The licensee's HCVS design will equivalent of one percent of absorb and reject decay heat such that meet the 1 % of rated thermal licensed/rated thermal power following a reactor shutdown from full power requirement while (unless a lower value is power containment pressure will be maintaining the drywell below the justified), and that the maintained below the primary primary containment pressure suppression pool and the containment design pressure limit of 53 limit (PCPL) with the wetwell filled HCVS together are able to PSIG [per square inch gauge]. with water (with a margin of 17%). absorb and reject decay heat, The required flow for 1 % rated such that following a reactor CAL-M15-013 is available for NRG review power (1,912 megawatt thermal shutdown from full power on the ePortal. (MWT)) is 71,750 lbm/hr. containment pressure is restored and then maintained No follow-up questions.
Attachment 3 below the primary containment design pressure and the primary containment pressure limit. Phase 1 ISE 01 3 DAEC has evaluated the potential effects The NRC staff reviewed the Closed of tornado missiles on HCVS components information provided in the 6-Make available for NRC staff above the protected area of the reactor month updates and on the [Staff evaluation to be audit evaluations of tornado building and confirmed that HCVS ePortal. included in SE Section missile effects on HCVS function will not be impaired.
HCVS 3.2.2] components above the components located above the protected In accordance with the protected area of the reactor area of the reactor building are limited to recommendations listed in Boiling building.
piping components and supports.
Water Reactor Owners Group (BWROG) Report TP-15-005 as detailed in Engineering Change (EC) 281991, with consideration of the DAEC HCVS design details, it has been determined that no additional missile protection is required for the HCVS piping above the 855'-0" elevation.
Per Chapter 3.8 of the Updated Final Safety Analysis Report, the Reactor Building (RB) superstructure metal siding is designed for wind loading, but may be blown off the RB by tornado winds. Therefore, tornado load pressures are applied to all piping routed through the RB above the 855'-0" elevation.
No follow-up questions.
Phase 1 ISE 01 4 The DAEC design has been The NRC staff reviewed the Closed modified since issuance of the information provided in the 6-Make available for NRC staff ISE. The HCVS system utilizes a month updates and on the [Staff evaluation to be audit additional detail on the dedicated penetration from the torus to ePortal. included in SE Section design features that minimize HCVS pipinq with no connecting systems 3.1.2.3] unintended cross flow of eliminating the possibility of unintended The licensee's design is vented fluids within a unit, cross flow. consistent with the guidance including a one line diagram provided in NEI 13-02 and containing sufficient detail to appears to minimize the confirm the description in the unintended cross flow of vented OIP. fluids. No follow-up questions.
Phase 1 ISE 01 5 The final DAEC design of the HCVS The NRG staff reviewed the Closed addresses the potential for hydrogen information provided in the 6-Provide a description of the detonation and deflagration with the use month updates and on the [Staff evaluation to be final design of the HCVS to of a nitrogen purge of the HCVS piping ePortal. included in SE Section address hydrogen detonation that ensures hydrogen and oxygen 3.1.2.11]
and deflagration.
concentrations within the HCVS system The licensee's design is are not susceptible to detonation or consistent with Option 3 of the deflagration (Option 3 of Appendix H of endorsed white paper HCVS-WP-NEI 13-02). The HCVS system isolation
- 03. is performed by two primary containment isolation valves (PCIVs) to minimize any No follow-up questions.
potential leakage. Prior to use of the system a partial purge of the system is performed to ensure no hydrogen is directly downstream of the PCIVs at the time of actuation.
A full nitrogen purge is performed immediately following each period of venting the torus. Each purge is performed with nitrogen flow at sufficient velocity to limit stratification an ensure turbulent flow to preclude retaining hydrogen in the pipe. The piping is slope upwards from the outboard PCIV to the atmospheric vent discharge to ensure hydrogen will exit the vent through buoyancy.
No trapped high points are provided in the piping. Phase 1 ISE 01 6 DAEC strategies for hydrogen control are The NRG staff reviewed the Closed as noted above in response to Open information provided in the 6-Provide a description of the Items 4 and 5. The HCVS system utilizes month updates and on the [Staff evaluation to be strategies for hydrogen control a dedicated penetration from the torus to ePortal. included in SE Section that minimizes the potential for HCVS piping with no connecting systems 3.1.2.12] hydrogen gas migration and and the HCVS piping does not pass The licensee's design is ingress into the reactor through other buildings thus eliminating consistent with the industry building or other buildings.
the potential for migration of hydrogen guidance and appears to gas from the HCVS into the reactor minimize the potential for building or other buildings.
Nitrogen hydrogen gas migration and purge of the system prior to use and ingress into the reactor building or immediately following isolation of the other buildings.
system prevents detonation or deflagration of hydrogen inside the HCVS No follow-up questions.
Option 3 of NEI 13-02 Appendix H). Phase 1 ISE 01 7 DAEC docketed an assessment of The NRC staff reviewed the Closed communications capabilities under ELAP information provided in the 6-Make available for NRC staff conditions in NG-12-0430 "Response to month updates and on the [Staff evaluation to be audit documentation that NRC 10 CFR 50.54(f)
Request for ePortal. included in SE Section demonstrates adequate Information Regarding Near-Term Task 3.1.1] communication between the Force Recommendation 9.3, Emergency The communication methods are remote HCVS operation Preparedness" (ADAMS Accession No. the same as accepted in Order locations and HCVS decision ML 12307A120).
NRC staff review of this EA-12-049.
makers during ELAP and assessment is documented in an NRC severe accident conditions.
Letter dated June 6, 2013 "Duane Arnold No follow-up questions.
Energy Center Staff Assessment in Response to Recommendation 9.3 of the Near Term Task Force Related to the Fukushima Dai-lchi Nuclear Power Plant Accident" (ADAMS Accession No. ML 13142A320).
The NRC staff concluded the communications assessment was reasonable to ensure communications were maintained during an ELAP. The HCVS operating locations are the main control room located in the control building and the Remote Operating Station [ROS] in the 1 A3 switchgear room also located in the control building.
Severe accident conditions do not have an impact on communications in the control building beyond those defined in the communications assessment for ELAP conditions.
HCVS decision makers are located in the control room so communication with the operating location in the control room can be made directly with no equipment requirements.
Operators at the Remote Operating Station can communicate with HCVS decision makers via a variety of methods including sound powered phones, hand held radios, plant page, or telephone.
Phase 1 ISE 01 8 DAEC has completed evaluations of The NRC staff reviewed the Closed temperature and radiological conditions to information provided in the 6-Make available for NRC staff ensure that operators can safely access month updates and on the [Staff evaluation to be audit an evaluation of and operate controls and support ePortal. included in SE Sections temperature and radiological equipment for the HCVS system. HCVS 3.1.1.2 and 3.1.1.3] conditions to ensure that controls and support equipment requiring Main Control Room temperatures operating personnel can safely access by operators are located within the have been addressed as part of access and operate controls control building to minimize radiological the FLEX order and were found to and support equipment.
and temperature challenges.
acceptable by the NRC staff. EC283904 description and CAL-R15-002 EC 283904 discusses the are available for NRG review on the environmental conditions for the eportal. (See also EVAL-16-M18)
ROS as it relates to personnel habitability and equipment operability.
CAL-R15-002 evaluates the radiological conditions in areas where operators are needed for HCVS operation.
Radiological conditions result in low operator dose. Based on these evaluations, the temperature and radiological conditions should not inhibit operator actions needed to initiate and operate the HCVS during an ELAP with severe accident conditions. No follow-up questions.
Phase 1 ISE 01 9 DAEC has completed final sizing The NRC staff reviewed the Closed evaluations for HCVS batteries to ensure information provided in the 6-Make available for NRC staff the batteries can power HCVS equipment month updates and on the [Staff evaluation to be audit the final sizing evaluation for a minimum of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. DAEC has ePortal. included in SE Section for HCVS batteries/battery completed an evaluation for the battery 3.1.2.6] charger including incorporation chargers to confirm they are capable of The licensee stated that all into FLEX DG loading recharging the HCVS batteries while electrical power required for calculation.
loaded. A review of the use of FLEX operation of HCVS components is diesel generators to power the HCVS provided by the HCVS battery chargers has confirmed the load is batteries/battery chargers.
within the capacity of the FLEX diesel generators.
The 480 VAC FLEX diesel The battery sizing calculation generators are equipped with two 50A (CAL-E15-002) confirmed that the output breakers and four 125A output HCVS batteries have a minimum breakers.
One of the 50A breakers will be capacity capable of providing connected to the HCVS UPS power for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> without [uninterruptible power supply] via a 200 recharging, and therefore is foot length cable. The voltage drop adequate.
across the cable for the assumed 8A UPS load is 1 .03 volt which is well within the The licensee provided EC +10/-12% allowable input voltage range 281991, which discusses re-specified by the UPS vendor, and is powering of the HCVS battery acceptable.
The UPS batteries are charger using a FLEX portable adequate for the first 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of HCVS DG. service. The addition of the small load of the HCVS UPS to the FLEX 480 VAC No follow-up questions.
generator after 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> is acceptable.
EC281991, including CAL-E13-001 and CAL-E15-002 are available for NRG review on the eportal. Phase 1 ISE 0110 DAEC has completed the final sizing The NRG staff reviewed the Closed evaluation (CAL-M15-014) of pneumatic information provided in the 6-Make available for NRG staff nitrogen supply that demonstrates month updates and on the [Staff evaluation to be audit the final sizing evaluation adequate capacity is installed for the first ePortal. included in SE Section for pneumatic N2 supply. 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of an ELAP event. After 24 3.1.2.6] hours replacement nitrogen bottles can be CAL-M15-014 evaluates the applied in an accessible location in the pneumatic design and sizing. control buildinq.
The evaluation discusses the required number of nitrogen CAL-M15-014 is available for NRC review cylinders needed for vent on the eportal. operation for sustained operation.
The number of nitrogen cylinders installed and available are sufficient to operate the HCVS for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. No follow-up questions.
Phase 1 ISE 01 11 As stated in NG-15-0169, Six The NRC staff reviewed the Closed Month Status Update, due to design information provided in the 6-Make available for NRC staff changes in vent location and routing, month updates and on the [Staff evaluation to be audit documentation of an existing containment isolation valves will ePortal. included in SE Section evaluation verifying the no longer be used for venting. New vent 3.2.1] existing containment isolation design will utilize a spare torus CAL-M 15-014 discusses the valves, relied upon for the penetration with two new primary valve/actuator information for the HCVS, will open under the containment isolation valves and a PCIVs. The NRC staff verified maximum expected differential rupture disk. the actuator can develop greater pressure during BDBEE and torque than the PCIV's unseating severe accident wetwell An evaluation (CAL-M15-014) has been torque. venting. done to ensure the two new containment isolation valves will open under the No follow-up questions.
maximum expected differential pressure during BDBEE [beyond-design-basis external event] and severe accident wet well venting. CAL-M15-014 is available for NRC review on the eportal. Phase 1 ISE 0112 DAEC has completed evaluations of key The NRG staff reviewed the Closed instruments and controls necessary to information provided in the 6-Make available for NRG staff implement NRG Order EA-13-109 month updates and on the [Staff evaluation to be audit descriptions of all including the qualification methods as part ePortal. included in SE Section instrumentation and controls of the engineering change package for 3.1.2.8] (existing and planned) the HCVS system to ensure the The existing plant instruments necessary to implement this instrumentation and controls are suitable required for HCVS (i.e. wetwell order including qualification for the application.
level instruments and drywell methods. pressure instruments) meet the See EC 281991. requirements of RG 1.97. EC 281991 provides a list of HCVS instruments and controls and associated qualifications for new HCVS l&C components.
The staff's review indicates that the qualification meets the order requirements.
No follow-up questions.
Phase 1 ISE 01 13 DAEC has completed evaluations of key The NRG staff reviewed the Closed components necessary for HCVS venting information provided in the 6-Make available for NRG staff to ensure they are capable of performing month updates and on the [Staff evaluation to be audit the descriptions of local their intended function under ELAP and ePortal. included in SE Section conditions (temperature, severe accident conditions including local 3.1.1.4] radiation and humidity) temperature, radiation and humidity as EC 281991 discusses the anticipated during ELAP and part of the engineering change package environmental conditions during severe accident for the for the HCVS system. an accident at the locations components (valves, containing l&C components.
The instrumentation, sensors, See EC281991.
staff's review indicated that the transmitters, indicators, environmental qualification met electronics, control devices, the order requirements.
and etc.) required for HCVS venting including confirmation No follow-up questions.
that the components are capable of performing their functions during ELAP and severe accident conditions.
Phase 1 ISE 01 14 As stated in NG-15-0169, Six The NRG staff reviewed the Closed Month Status Update, the qualification information provided in the 6-Provide a justification for method used for each HCVS instrument month updates and on the [Staff evaluation to be deviating from the will be to the [Institute of Electrical and ePortal. included in SE Section instrumentation seismic Electronics Engineers]
IEEE 344-2004 3.1.1.4] qualification guidance standard or a substantially similar The NRG confirmed the OIP specified in NEI 13-02, industrial standard and therefore will not change that now complies with endorsed, in part, by JLD-ISG-be deviating from NEI 13-02 or [Japan the NEI 13-02 guidance.
2013-02 as an acceptable Lessons-Learned Division-Interim Staff means for implementing Guidance]
JLD-ISG-2013-02. No follow-up questions.
applicable requirements of Order EA-13-109. Phase 2 ISE 01 1 Started. The NRC staff reviewed the Open information provided in the 6-Licensee to evaluate the During the audit call (2/8/18), the licensee month updates and on the [Staff evaluation to be SAWA [severe accident water informed the NRC staff that the ePortal. included in SE Sections addition]
equipment and temperature evaluation addressed in 4.5.1.2 and 4.5.1.3] controls, as well as ingress Phase 1 Open Item #8 bounds the The licensee has not completed and egress paths for the SAWA/SAWM operation.
The licensee the dose assessment for operator expected severe accident also informed the NRC staff that DAEC is actions or SAWA/SAWM conditions (temperature, still performing the dose assessment for equipment and controls needed to humidity, radiation) for the SAWA/SAWM operation.
initiate and operate the HCVS sustained operating period. during an ELAP with severe accident conditions.
This item will stay open until the licensee completes the dose assessment and provides the NRC staff more information which shows that radiological conditions should not inhibit operator actions or SAWA equipment and controls needed to initiate and operate the HCVS during an ELAP with severe accident conditions.
Phase 2 ISE 01 2 Complete.
The NRC staff reviewed the Closed information provided in the 6-Licensee to demonstrate that As a follow-up to the audit call (2/8/18), month updates and on the [Staff evaluation to be SAWA components and the licensee provided a simplified drawing ePortal. included in SE Section connections external to of the SAWA piping. 4.1.1.1] protected buildings have been The NRC staff reviewed SAWA protected against the pipe drawing and verified that the screened-in hazards of Order SAWA components and EA-12-049 for the station. connections external to protected buildings have been protected against the screened-in hazards of Order EA-12-049.
No follow-up questions.
Phase 2 ISE 01 3 Complete.
The NRC staff reviewed the Closed information provided in the 6- Licensee to demonstrate that month updates and on the [Staff evaluation to be containment failure as a result ePortal. included in SE Section of overpressure can be 4.2] prevented without a drywell EVAL-16-M01, "Determination of vent during severe accident Suppression Pool Volume at conditions.
Specific Water Levels to Support Severe Accident Water Management (SAWM) Strategies," Revision 1 provides a basis for OIP Attachment 2.1.G, "SAWA/SAWM Plant-Specific Datum." The available freeboard is defined as the distance between maximum normal wetwell level and the maximum wetwell level instrument range. The freeboard height is 5'-7" which translates to 303,000 gallons. Additional freeboard is represented by the distance from the maximum wetwell level instrument range and the HGVS opening. The additional freeboard volume is 375,119 gallons. The initial SAWA flow rate is 272 gpm [gallons per minute] for 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> followed by 55 gpm for a sustained coping period of 7 days. No follow-up questions.
Phase 2 ISE 01 4 Started. The NRG staff reviewed the Open information provided in the 6-Licensee to demonstrate how month updates and on the [Staff evaluation to be the plant is bounded by the ePortal. included in SE Section reference plant analysis that 4.2.1.1] shows the SAWM strategy is The licensee did not provide the successful in making it unlikely NRG staff with any comparison of that a drvwell vent is needed. parameters between the reference plant to those of Duane Arnold. The NRG staff can not verify that it is unlikely the suppression chamber HCVS could become blocked leading to a successful SAWA/SAWM strategy.
This item will stay open until the licensee provides the NRG staff more information which concludes that it is unlikely a drywell vent would be required to maintain containment integrity.
Phase 2 ISE 01 5 Closed The NRG staff reviewed the Closed information provided in the 6-Licensee to demonstrate that During the audit call (2/8/18), the licensee month updates and on the [Staff evaluation to be there is adequate informed the NRC staff that the ePortal. included in SE Section communication between the communication methods are the same as 4.1] MGR and the operator at the accepted in Order EA-12-049, as stated The communication methods are FLEX pump during severe above in Phase 1 Open Item #7. the same as accepted in Order accident conditions.
No follow-up questions. Phase 2 ISE 01 6 Not Started. The NRG staff reviewed the Open information provided in the 6-Licensee to demonstrate the During the audit call (2/8/18), the licensee month updates and on the [Staff evaluation to be SAWM flow instrumentation informed the NRG staff that the specific ePortal. included in SE Sections qualification for the expected flow meter to be used at DAEG has not 4.4.1.3 and 4.5.1.2] environmental conditions.
yet been determined.
Since the licensee has not yet determined the flow meter to be used, no information on the qualification for the expected environmental conditions could be provided to the NRG staff. This item will stay open until the licensee provides the NRG staff more information which determines the accuracy of the flow meter and the environmental qualifications related to the performance of the flow meter in order to meet the intent of Order EA-13-109.
D.Cu~and
SUBJECT:
DUANE ARNOLD ENERGY CENTER -REPORT FOR THE AUDIT OF LICENSEE RESPONSES TO INTERIM STAFF EVALUATIONS OPEN ITEMS RELATED TO NRC ORDER EA-13-109 TO MODIFY LICENSES WITH REGARD TO RELIABLE HARDENED CONTAINMENT VENTS CAPABLE OF OPERATION UNDER SEVERE ACCIDENT CONDITIONS (CAC NO. MF4391; EPID L-2014-JLD-0039)
DATED March 5, 2018 DISTRIBUTION:
PUBLIC PBEB R/F RidsNrrDorllpl3 Resource RidsNrrPMDuaneArnold Resource RidsNrrlaSLent Resource ADAMS Accession No.: ML 180570298 RidsRgn3MailCenter Resource TBrown, NRR RAuluck, NRR Blee, NRR RidsACRS_MailCTR Resource OFFICE NRR/DLP/PBEB/PM NRR/DLP/PBMB/LA NRR/DLP/PBEB/BC NRR/DLP/PBEB/PM NAME RAuluck Slent TBrown RAuluck DATE 2/28/18 2/27/18 3/5/18 3/5/18 OFFICIAL RECORD COPY