ML18135A436
| ML18135A436 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 05/29/2018 |
| From: | Rajender Auluck Beyond-Design-Basis Engineering Branch |
| To: | Bryan Hanson Exelon Nuclear Generation Corp |
| Lee B | |
| References | |
| CAC MF4418, CAC MF4419, EA-13-109, EPID L-2014-JLD-0051 | |
| Download: ML18135A436 (26) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 May 29, 2018 Mr. Bryan C. Hanson Senior Vice President Exelon Generation Company, LLC President and Chief Nuclear Officer Exelon Nuclear 4300 Winfield Road Warrenville, IL 60555
SUBJECT:
LIMERICK GENERATING STATION, UNITS 1 AND 2 - 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 NOS. MF4418 AND MF4419; EPID L-2014-JLD-0051)
Dear Mr. Hanson:
On June 6, 2013 (Agencywide Documents Access and Management System (ADAMS)
Accession No. ML13143A334), 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 Conditions," 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 30, 2014 (ADAMS Accession No. ML14181A418), Exelon Generation Company, LLC (the licensee) submitted its Phase 1 OIP for Limerick Generating Station, Units 1 and 2 (LGS, Limerick). By letters dated December 17, 2014, June 30, 2015, December 15, 2015 (which included the combined Phase 1 and Phase 2 OIP), June 30, 2016, December 15, 2016, June 30, 2017, and December 15, 2017 (ADAMS Accession Nos. ML14353A110, ML15181A016, ML15364A014, ML16182A011, ML16350A266, ML17181A031, and ML17349A035, 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 (ISEs) for Phase 1 and Phase 2 of Order EA-13-109 for Limerick by letters dated April 1, 2015 (ADAMS Accession No. ML15082A433), and August 2, 2016 (ADAMS Accession No. ML16116A320), respectively. When developing the ISEs, the staff identified open items where additional information was still needed to complete its review.
The NRC staff is using the audit process described in 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 being performed for 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 a teleconference with the licensee on May 3, 2018. 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 Nos. 50-352 and 50-353
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 EXELON GENERATION COMPANY, LLC LIMERICK GENERATING STATION, UNITS 1 AND 2 DOCKET NOS. 50-352 AND 50-353 BACKGROUND On June 6, 2013 (Agencywide Documents Access and Management System (ADAMS)
Accession No. ML13143A334), 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 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 drywall 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 drywall 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 30, 2014 (ADAMS Accession No. ML14181A418), Exelon Generation Company, LLC (Exelon, the licensee) submitted its Phase 1 OIP for Limerick Generating Station, Units 1 and 2 (LGS, Limerick). By letters dated December 17, 2014, June 30, 2015, December 15, 2015 (which included the combined Phase 1 and Phase 2 OIP), June 30, 2016, December 15, 2016, June 30, 2017, and December 15, 2017 (ADAMS Accession Nos.
ML14353A110, ML15181A016, ML15364A014, ML16182A011, ML16350A266, ML17181A031, and ML17349A035, 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 Limerick by letters dated April 1, 2015 (ADAMS Accession No. ML15082A433), and August 2, 2016 (ADAMS Accession No. ML16116A320), respectively. When developing the ISEs, the staff identified open items where additional information was needed to complete its review.
The NRC 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 NRC staff conducted a teleconference with the licensee on May 3, 2018. The purpose of this 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 the audit call, 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, other related documents (e.g. white papers (ADAMS Accession Nos.
ML14126A374, ML14358A040, ML15040A038 and ML15240A072, respectively) and frequently asked questions (FAQs), (ADAMS Accession No. ML15271A148)) 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 Limerick. The open items are taken from the Phase 1 and Phase 2 ISEs issued on April 1, 2015, and August 2, 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 Limerick, 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 FIP, 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 Team Lead/Sr. Project Manager Rajender 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 Kerby Scales NRR/DLP Technical Support - Balance of Plant Garry Armstrong NRR/DLP Technical Support - l&C Steve Wyman NRR/DLP Technical Support - Dose John Parillo NRR/DRA
Table 2 - Audit Documents Reviewed Design Change Package (DCP) 423381, "1 R17 MOD - Fukushima Hardened Vent-Online Work 16-00130/ECR-DCP," Revision 3 Design Change Package (DCP) 423333, "2R14 MOD - Fukushima Hardened Vent - Online Elect/l&C Work 16-00013/ECR-DCP," Revision 3 Calculation LE-0128, "HCVS Battery and Battery Charger Sizing S&L/ECR 16-003," Revision 0 Calculation M-81-30, "Diesel Generator Building Corridor HVAC Loads," Revision 1 Engineering Change (EC) 622673, "Temperature, Humidity and Radiological Evaluation HCVS
& SAWA/SAWM," Revision 0 Calculation LM-0721, "Hardended Containment Vent System Dose Assessment," Revision 0 Calculation LM-0709, "Limerick Hardened Containment Vent Capacity," Revision 0 Design Change Package (DCP) 423331, "2R14 MOD - Fukushima Hardened Vent-Online Work 16-00011/ECR-DCP," Revision 2 Design Change Package (DCP) 422831, "Unit 2 HCVS Safeguards Room Train Bay Large Bore Piping 13-00264/ECR-DCP," Revision 3 Calculation LM-0723, "HCVS PCIV Compressed Air Bottle Requirements," Revision 1 Calculation LM-0724, "Hardened Containment Vent Purge System Design Calculation,"
Revision 1 Calculation LM-0725, "FLEX Activity and HCVS Phase 2 Dose Assessment," Revision O BWROG-TP-008, "Severe Accident Water Addition Timing" BWROG-TP-011, "Severe Accident Water Management Supporting Evaluations"
ISE Open Item Number Requested Action Phase 1 ISE 01 1 Make available for NRC staff audit documentation of a method to disable HCVS during normal operation to provide assurances against inadvertent operation that also minimizes actions to enable HCVS operation following an ELAP.
Limerick Generating Station, Units 1 and 2 Vent Order Interim Staff Evaluation Open Items:
Table 3 - ISE Open Item Status Table Licensee Response - Information NRC Staff Close-out notes provided in 6 month updates and on the ePortal Unit 1 - Complete The NRC staff reviewed the information provided in the 6-The system is designed to prevent month updates and on the inadvertent operation. The new control ePortal.
switch HS-057V-183 installed in the main control room (MCR) panel 1 O-C689 Engineering Change (EC) 423381 is a keylock switch. The switch is kept and EC 423333, in part, locked in "OFF" position (with key discusses the control mechanism removed) to prevent inadvertent powering for HCVS during normal of the HCVS components from 125 Vdc operation. The licensee provided
[volts direct current] HCVS battery source.
details in the document on Additionally, locked valves are used with maintaining the HCVS in the the gas bottles to prevent inadvertent "OFF" condition and only being operation. (Reference EC 423381 section accessible as directed by revised 3.19).
procedures. The new control switch installed in the MCR panel Unit 2 - Complete is a keylock switch. Additionally, locked valves are used with the The system is designed to prevent gas bottles to prevent inadvertent inadvertent operation. The new control operation.
switch HS-057V-283 installed in the MCR panel 20-C689 is a keylock switch. The No follow-up questions.
switch is kept locked in "OFF" position (with key removed) to prevent inadvertent powering of the HCVS components from 125 Vdc HCVS battery source.
Additionally, locked valves are used with the gas bottles to prevent inadvertent operation. (Reference EC 423333 section 3.19).
Safety Evaluation (SE) status Closed; Pending; Open (need additional information from licensee)
Closed
[Staff evaluation to be included in SE Section 3.1.2.7]
EC 423333 and EC423381 are available in ePortal.
Phase 1 ISE 01 2 Unit 1 - Complete The NRC staff reviewed the Closed information provided in the 6-Make available for NRC staff The HCVS batteries have been sized to month updates and on the
[Staff evaluation to be audit the final sizing evaluation meet the requirements of the HCVS ePortal.
included in SE Section for HCVS batteries/battery system and function for the initial 24 3.1.2.6]
charger including incorporation hours into the event. (Reference The licensee stated that all into FLEX DG loading Calculation LE-0128).
electrical power required for calculation.
operation of HCVS components is The FLEX diesel generator loading is provided by the 125 Vdc acceptable and rated loading of the FLEX battery/battery charger.
diesel generator will not be exceeded due to the additional HCVS loading.
The battery sizing calculation (L-(Reference EC 423381 section 3.35).
0128) confirmed that the HCVS batteries have a minimum Unit 2 - Complete.
capacity capable of providing power for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> without The HCVS batteries have been sized to recharging, and therefore is meet the requirements of the HCVS adequate.
system and function for the initial 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> into the event. (Reference The licensee provided DCS Calculation LE-0128)
Section 3.35 for EC 423333 and EC 423381, which discusses re-The FLEX diesel generator loading is powering of the HCVS battery acceptable and rated loading of the FLEX charger using a FLEX DG.
diesel generator will not be exceeded due to the additional HCVS loading.
No follow-up questions.
(Reference EC 423333 section 3.35).
LE-0128, EC 423333 and EC 423381 are available in ePortal.
Phase 1 ISE 01 3 Unit 1 - Complete The NRC staff reviewed the Closed information provided in the 6-Make available for NRC staff The primary operating station for HCVS month updates and on the
[Staff evaluation to be audit an evaluation of operation is located in the MCR. A ePortal.
included in SE Sections temperature and radiological remote operating station (ROS) is located 3.1.1.2 and 3.1.1.3]
conditions to ensure that in the emergency diesel generator (EOG)
MCR temperatures have been operating personnel can safely Corridor, EL. 217' (Room 313). The ROS addressed as part of the FLEX access and operate controls location and travel path to ROS location order and were found to and support equipment was evaluated for habitability and acceptable by the NRC staff.
accessibility during a severe accident.
(Reference EC 423382 section 3.19).
EC 423281 and EC 423382 discusses the environmental Unit 2 - Complete conditions for the ROS as it relates to personnel habitability The primary operating station for HCVS and equipment operability.
operation is located in the MCR. A remote operating station (ROS) is located The maximum expected in the EOG Corridor, EL. 217' (Room temperature in the ROS location 317). The ROS location and travel path in the EOG corridor is 120 to ROS location was evaluated for degrees Farenheit (°F). This habitability and accessibility during a temperature is expected to occur severe accident. (Reference EC 423281 due to a non-safety-related section 3.19).
heating steam pipe rupturing during a seismic EC 423281 and 423382 are available in event. To mitigate this issue, the ePortal.
heating steam pipe was analyzed and additional supports have been installed to ensure the piping will not rupture (EC 423333 and EC 423381 ). There are no additional process fluid piping or heat generating equipment that would add significant heat to this area. Therefore, the area will then be at outside ambient conditions which does not normally exceed 100 °F. In addition, operator stay time in the ROS is limited. If required, operating personnel working in high temperature areas will be protected using guidance in SA-AA-111, Heat Stress Control.
Calculation LM-0721, "Hardended Containment Vent System Dose Assessment," Revision O was performed to determine the integrated radiation dose due to HCVS operation. The NRC staff reviewed this calculation and determined that the licensee used conservative assumptions and followed the guidance outlined in NEI 13-02 Rev.1 and HCVS-WP-02 Rev. 0. Based on the expected integrated whole body dose equivalent in the MCR and ROS and the expected integrated whole body dose equivalent for expected actions during the sustained operating period, the NRC staff believes that the order requirements are met.result in low operator dose.
Based on the 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 4 Unit 1 and Unit 2 - Complete The NRC staff reviewed the Closed information provided in the 6-Make available for NRC staff The required one percent capacity at the month updates and on the
[Staff evaluation to be audit analyses demonstrating lower of Primary Containment Pressure ePortal.
included in SE Section that HCVS has the capacity to Limit (PCPL) or containment design 3.1.2.1]
vent the steam/energy pressure will be verified using Reactor Calculation LM-709 used a rated equivalent of one (1) percent Excursion and Leak Analysis Program thermal power of 3,952 MWt of licensed/rated thermal (RELAP). In addition, Modular Accident
[megawatt thermal]. The flow rate power (unless a lower value is Analysis Program (MAAP) analyses will equivalent of 1 % reactor power justified), and that the be credited to verify that venting can be thermal energy is 147,708 lbm/hr.
suppression pool and the delayed for at least three hours and that HCVS flow at 63.76 psia [per HCVS toqether are able to anticipatory venting can be credited to square inch absolute] is 149,540 absorb and reject decay heat, maintain Reactor Core Isolation Cooling lbm/hr. (Vent capacity summary such that following a reactor (RCIC) functional. Unit 1 (Reference EC table on page 24 of calculation) shutdown from full power 423382 Section 3.33 and LM-709). Unit 2 containment pressure is (Reference EC 423281 Section 3.33 and No follow-up questions.
restored and then maintained LM-709).
below the primary containment design pressure and the EC 423281, EC 423382, and LM-709 are primary containment.
available in ePortal.
Phase 1 ISE 01 5 Complete The NRC staff reviewed the Closed information provided in the 6-Make available for NRC staff (Reference EC 423331 section 3.2, 3.5, month updates and on the
[Staff evaluation to be audit the seismic and tornado 3.9, and 3.38 (formally known as 16-ePortal.
included in SE Section missile final design criteria for 00011) and EC 423332 section 3.38 3.2.2]
the HCVS stack.
(formally known as 16-00012), and EC EC 423331, EC 423332, and EC 422831 section 3.24 (formally known as 422831 addresses the HCVS13-264)) describe seismic and tornado seismic qualification and tornado missile design criteria for HCVS stack.
missile design.
EC pkgs 423331, 423332, and 422831 The licensee evaluated the entire are available in ePortal for review.
HCVS system to Seismic Catergory I, which is consistent with the plants seismic design basis.
For the tornado missile design the licensee relies on NRG-endorsed HCVS-WP-04. Section 3.0 of the white paper defines 30-feet above grade as the highest grade within 300 yards of the HCVS structure for potential tornado missles evaluation. HCVS is routed inside the Reactor Building until it exits to the South Stack structure.
That structure also provides additional protection from wind generated missiles.
No follow-up questions.
Phase 1 ISE 01 6 Unit 1 and Unit 2 - Complete The NRC staff reviewed the Closed information provided in the 6-Make available for NRC staff HCVS is designed to minimize the impact month updates and on the
[Staff evaluation to be audit the descriptions of local of elevated temperatures, due to the ePortal.
included in SE Section conditions (temperature, potential loss of ventilation, radiation and 3.1.1.4]
radiation and humidity) humidity impact on the ability of operators EC 423281 and EC 423382, and anticipated during ELAP and to initiate and maintain the functionality of Table 1 in EC 622673, severe accident for the the HCVS. The locations of system
Temperature, Humidity and components (valves, equipment that require operator action Radiological Evaluation HCVS &
instrumentation, sensors, and the travel paths to reach the controls SAWNSAWM [severe accident transmitters, indicators, and indications are in mild environments.
water addition/ severe accident electronics, control devices, Unit 1 (Reference EC 423382 section water management]," Revision 0 and etc.) required for HCVS 3.19 and 3.24). Unit 2 (Reference EC discusses the environmental venting including confirmation 423281 section 3.19 and 3.24).
conditions during an accident at that the components are the locations containing l&C capable of performing their EC 423281 and EC 423382 are available components. The staffs review functions during ELAP and in ePortal for review.
indicated that the environmental severe accident conditions.
qualification met the order The loss of all general area lighting, requirements.
coincident with the ELAP, does not pose a threat to the operators' ability to access No follow-up questions.
and operate HCVS, since self-contained emergency lights illuminate the travel paths and handheld or portable lighting is available to manipulate HCVS equipment.
Phase 1 ISE 01 7 Unit 1 and Unit 2 - Complete The NRC staff reviewed the Closed information provided in the 6-Make available for NRC staff HCVS is designed to operate for first 24 month updates and on the
[Staff evaluation to be audit documentation of the hours with installed independent ePortal.
included in SE Section HCVS nitrogen pneumatic pneumatic air supply, thereby eliminating 3.1.2.6]
system design including sizing the reliance on portable equipment.
EC 423333 and EC 423381 and location.
HCVS is also designed for multiple discuss the pneumatic design and venting and purge cycles during the first sizing. Calculation LM-0723, 24-hour period without the need to "HCVS PCIV [primary recharge pneumatic air supply is located containment isolation valve]
in the emergency diesel corridor. Unit 1 Compressed Air Bottle (Reference EC 423381 section 3.19 and Requirements," Revision 1 and Calculation LM-0723). Unit 2 (Reference Calculation LM-0724, "Hardened EC 423333 section 3.19 and Calculation Containment Vent Purge System LM-0723).
DesiQn Calculation," Revision 1 provides verification of the bottle EC 423333, EC 423381, and calculation size calculation. Two bottles at a LM-0723 are available in ePortal for minimum of 1500 per square inch review.
gauge (psig) are required for temperatures below 121°F. The HCVS is based on 8 vent cycles in 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. Additionally, the licensee determined that 20 argon bottles valved in has a minimum pressure of 2300 psig for temperatures at 70°F. Bottles are replaced after 4 vent cycles.
No follow-up questions.
Phase 1 ISE 01 8 Complete The NRC staff reviewed the Closed information provided in the 6-Make available for NRC staff This communication method is the same month updates and on the
[Staff evaluation to be audit documentation that as accepted in Order EA-12-049. These ePortal.
included in SE Section demonstrates adequate items will be powered and remain 3.1.1.1]
communication between the powered using the same methods as The communication methods are remote HCVS operation evaluated under EA-12-049 for the period the same as accepted in Order locations and HCVS decision of sustained operation, which may be EA-12-049.
makers during El.AP and longer than identified for EA-12-049.
severe accident conditions.
No follow-up questions.
Communication will be via the plant radio system if available. If the radio system is not available, the Plant page system can be used. The page system was modified for FLEX to include a UPS
[uninterruptable power supply] that can be manually aligned to repower the system.
(Reference AR 2492527-42).
AR 2492527-42 is available in ePortal for review.
Phase 1 ISE 01 9 Unit 1 and Unit 2 - Complete The NRC staff reviewed the Closed information provided in the 6-Provide a description of the HCVS has been designed to ensure the month updates and on the
[Staff evaluation to be final design of the HCVS to flammability limits of gases passing ePortal.
included in SE Section through the system are not reached. The 3.1.2.11]
address hydrogen detonation vent piping is routed with a continuously Licensee uses argon to purge the and deflagration.
upward slope. A purge gas (argon) supply HCVS piping of hydrogen to limit system has been provided to displace the possibility of a hydrogen potentially flammable/denotable mixtures deflagration/detonation. EC of gases that may be present in the vent 423381 and EC 423333 after system actuation. The purge gas discusses the argon purge supply system is designed for four purge system, including the volume of cycles during the first 24-hour period Argon to burst the rupture disk, without the need to recharge. Unit 1 which is designed for 4 purges in (Reference EC 423381 section 3.19).
the first 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. The NRC staff Unit 2 (Reference EC 423333 section also noted that oxygen monitoring 3.19) systems are being installed to alert personnel of oxygen EC 42333 and 423381 are available in deficient environment where the ePortal for review.
argon is used.
The licensee's design is consistent with Option 3 of the NRG-endorsed white paper HCVS-WP-03.
No follow-up questions.
Phase 1 ISE 01 10 Unit 1 - Complete The NRC staff reviewed the Closed information provided in the 6-Provide a description of the As discussed in the December 2015 OIP, month updates and on the
[Staff evaluation to be strategies for hydrogen control the Limerick wetwell vent line for each ePortal.
included in SE Section that minimizes the potential for unit has a dedicated HCVS flow path from 3.1.2.12]
hydrogen gas migration and the wetwell penetration to the outside with The HCVS wetwell pipe in each ingress into the reactor no interconnected system. The discharge each unit provides a dedicated building or other buildings.
point meets the guidance of "HCVS HCVS flowpath from the wetwell Release Point", HCVS-FAQ-04.
penetration PCIVs to the outside with no interconnected Unit 2 - Complete downstream piping. The staff's review of the proposed system (Reference EC 423281 and Calculation indicates that the licensee's LM-0709) design appears to maintain hydrogen below flammability EC 423281 and calculation LM-0709 are limits.
available in ePortal for review.
No follow-up questions.
Phase 1 ISE 01 11 Unit 1 - Complete The NRC staff reviewed the Closed information provided in the 6-Make available for NRC staff Seismic documentation has been month updates and on the
[Staff evaluation to be audit documentation of a provided EC 423381, Section 3.4, EC ePortal.
included in SE Section seismic qualification evaluation 423382, Section 3.4, and AR 2492527-97.
3.2.2]
of HCVS components.
The licensee provided several Unit 2 - Complete qualification reports which demonstrate the seismic Seismic documentation has been adequacy of the HCVS provided in Reference EC 423331 section components. These seismic 3.4 and 3.38, 423333 section 3.4, 3.38 qualification reports indicates the and attachment 45, and 617568 section HCVS piping, components, 3.2.
supports, and wall penetrations are classified as Seismic Class EC 423331, EC 423333, EC 617568, EC IIA but are designed to Seismic 423381, EC 423382, and AR 2492527-97 Class 1 Criteria. The NRC staff are available in ePortal for review.
reviewed these reports and confirmed that the components required for HCVS venting remain functional following a design basis earthquake.
No follow-up questions.
Phase 1 ISE 01 12 Unit 1 - Complete The NRC staff reviewed the Closed information provided in the 6-Make available for NRC staff EC 423381 installed and qualified the month updates and on the
[Staff evaluation to be audit descriptions of all following components in the MCR and in ePortal.
included in SE Section instrumentation and controls the plant 3.1.2.8]
(existing and planned)
The existing plant instuments necessary to implement this valve position indicating lights, required for HCVS (i.e. wetwell order including qualification power key-locked switch, level instruments and drywell methods.
temperature indicator displays, pressure instruments) meet the radiation monitoring system requirements of RG 1.97.
consisting of an element local to the HCVS vent pipe, and a EC 423381 and EC 423333 monitor. (Reference EC 423381 discusses the qualifications for section 3.19 and 3.36).
new HCVS l&C components. The NRC staff's review indicated that the qualification met the order requirements.
Existing pressure instrument Pl-042-170-1 will be used to monitor containment No follow-up questions.
pressure in the drywell. The transmitter (PT-042-170) has been replaced with an RG 1.97 qualified component to ensure this will remain functioning during the event. See EC 423381 for replacement and EC 423382 section 3.19 for qualification of the component.
Unit 2 - Complete EC 423333 installed and qualified the following components in the MCR and in the plant:
valve position indicating lights, power key-locked switch, temperature indicator displays, radiation monitoring system consisting of an element local to the HCVS vent pipe, and a monitor. (Reference EC 423333 section 3.19 and 3.36).
Existing pressure instrument Pl-042-270-1 will be used to monitor containment pressure in the drywell. See EC 617568 section 3.2 for qualification of the component.
EC 423333, 617568, EC 423381 and EC 423382 are available in ePortal for review.
Phase 1 ISE 01 13 Unit 1 - Started The NRC staff reviewed the Closed information provided in the 6-Make available for NRC staff Unit 2 - Complete month updates and on the
[Staff evaluation to be audit the procedures for HCVS ePortal.
included in SE Section operation.
Reference the following procedures.
5.1]
SAMP-1 Sht 1 -7: RPV and Primary The Unit 2 guidelines and Containment Flooding Control SAMP-2 procedures for HCVS operation Sht 1-3: Containment and Radioactivity are complete and consistent with Release Control T-101: RPV Control T-the guidance in NEI 13-02.
102: Primary Containment Control SPIT, SP/L, PC/P, DW/T, PC/H T-111: RPV The Unit 1 guidelines and Level Restoration/Steam Cooling T-116:
procedures for HCVS operation RPV Flooding T-117: Level/Power will be developed and will follow Control T-334: FLEX Generator the same guidance as Unit 2, Connection for Repowering DIV 2 Battery consistent with the guidance in Charger T-341: Primary Containment NEI 13-02.
Venting Via Hardened Containment Vent System RT-6-000-914-0: Inspection of No follow-up questions.
FLEX Pump Storage Building Equipment RT-6-000-915-0: Inspection of FLEX Generator Storage Building Equipment RT-6-000-916-0: Routine Inspection of Spare HCVS Argon and Air Bottles RT 057V-400-2: HCVS PCIV Valve Exercise Test GP-19: Operator Activities ST 092-1 16-2 D22: Diesel Generator 4KV SFGD Loss of Power LSF-SM and Outage Testing RT-6-092-452-2:
Procedure for Deenergizing and Reenergizing the D22 Safeguard Bus During a Refuel Outage ST-6-092-1 18-2:
D24 Diesel Generator 4KV SFGD Loss of Power LSF-SM and Outage Testing RT 092-452-2: Procedure for Deenergizing and Reenergizing the D22 Safeguard BUS during a Refueling outage ST-6-060-460-2: Primary Containment Isolation Capability Check OP-LG-108-103-1 102:
Limerick Generating Station Unit 2 Locked Valve List RT-6-000-360-2: Unit 2 Accessible Locked Valve Walkdown 2S57V.1.A: Equipment Alignment of the Hardened Containment Vent System for Normal Operation SE-10-1: Breaker Reset Following LOCA RT-6-057V-901-2:
HCVS Battery Monthly Check RT-6-057V-902-2 HCVS Battery Quarterly Check F-R-714: South Stack Instrument Room 714 F-D-317: Unit 2 Diesel Generator Access Coordinate and Condensate Pump Rooms 317 and 318 (El 217') F-FPSB-001: Pre-Fire Plan Strategy for FLEX Pump Storage Building 2S92. 1.N:
Equipment Alignment for 2A Diesel Generator Operator S57V.8.A: Startup of the HCVS Battery Charger S57V.8.B:
Shutdown of the HCVS Battery Charger ST-6-076-360-2: RX ENCL SEC CNTMT Integrity Verification.
These procedures are in ePortal for review.
Phase 2 ISE 01 1 Unit 1 and Unit 2 - Complete The NRC staff reviewed the Closed information provided in the 6-Licensee to demonstrate that Per Drawing HBD-842-01, the HCVS pipe month updates and on the
[Staff evaluation to be the HCVS components leaves the protected structure more than ePortal.
included in SE Section meeting reasonable protection 120 feet above grade elevation, which is 3.2.2]
from tornado missiles is at 217 feet main sea level (MSL), as For the tornado missile design the least 30 feet above the highest indicated on site topographical drawing C-licensee relies on NRC-endorsed grade within 300 yards.
0062 that shows grade elevation HCVS-WP-04. Section 3.0 of the referenced to MSL within 300 yards of the white paper defines 30-feet above HCVS components evaluated.
grade as the highest grade within 300 yards of the HCVS structure for potential tornado missile evaluation. HCVS is routed inside the Reactor Building until it exits to the South Stack structure.
That structure also provides additional protection from wind generated missiles.
No follow-up questions.
Phase 2 ISE 01 2 Unit 1 and Unit 2 - Complete The NRC staff reviewed the Closed information provided in the 6-Licensee to confirm through Actions taken within the first hour (prior to month updates and on the
[Staff evaluation to be analysis the temperature and start of core damage) from the start of the ePortal.
included in SE Sections radioloqical conditions to ELAP are acceptable from an 4.1.1.4 and 4.2.1.41 ensure that operating environmental and radiological For temperature review of the personnel can safely access perspective without further evaluation.
MCR and ROS, see Phase 1 ISE and operate controls and Open ltem-3 above. As noted in support equipment.
For actions within the MCR are Phase 1 ISE Open ltem-3, above, acceptable for the entire period of if required, operating personnel Sustained Operation per HCVS-FAQ-06 working in high temperature areas Assumption 049-21.
will be protected using guidance in SA-AA-111, Heat Stress For actions within the Reactor Building Control. The use of SA-AA-111 and between 1 and 7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br />, evaluation of heat stress controls, it is expected temperatures and dose rates reasonable to assume the has been performed and determined to be operator actions required to acceptable. (Reference EC622673, and implement the HCVS and calculations LM-0721 and LM-0725).
SAWNSAWM strategies can be accomplished.
For locations outside the Reactor Building between 7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br /> and 7 days, Limerick Calculation LM-0725, "FLEX performed evaluations for the temperature Activity and HCVS Phase 2 Dose and radiological conditions for the Assessment," Revision O was equipment and deployment locations, performed to determine the including ingress/egress paths and integrated radiation dose due to determined them to be acceptable.
HCVS operation.
(Reference EC 622673, and calculations LM-0721 and LM-0725). EC 622673, LM-Temperature and radiological 0721 and LM-0725 are available in conditions should not inhibit ePortal for review.
operator actions or SAWA equipment and controls needed to initiate and operate the HCVS during an ELAP with severe accident conditions.
No follow-up questions.
Phase 2 ISE 01 3 Unit 1 and Unit 2 - Complete The NRC staff reviewed the Closed information provided in the 6-Licensee to evaluate the Equipment and Controls month updates and on the
[Staff evaluation to be SAWA equipment and ePortal.
included in SE Sections controls, as well as the ingress Plant instrumentation for SAWNSAWM 4.1.1.4 and 4.2.1.4]
and egress paths for the that is qualified to RG 1.97 or equivalent EC 622673, "Temperature, expected severe accident is considered qualified for the sustained Humidity and Radiological conditions (temperature, Evaluation HCVS &
humidity, radiation) for the operating period without further SAWNSAWM," Revision O along sustained operating period.
evaluation.
with calculations LM-0721 and LM-0725 shows that temperature Passive components that do not need to and radiological conditions should change state after initially establishing not inhibit operator actions or SAWA flow do not require evaluation SAWA equipment and controls beyond the first 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />, at which time needed to initiate and operate the they are expected to be installed and HCVS during an ELAP with ready for use to support SAWNSAWM.
severe accident conditions.
The following additional equipment No follow-up questions.
performing an active SAWNSAWM function is considered:
SAWNSAWM flow instrument SAWNSAWM/FLEX pump SAWNSAWM/FLEX generator Active valves in SAWA flow path Ingress and Egress For locations outside the Reactor Building between 7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br /> and 7 days when SAWA is being utilized, Limerick performed evaluations of expected temperatures, humidity and the dose rates and determined them to be acceptable.
(Reference EC 622673, and calculations LM-0721 and LM-0725).
EC 622673, LM-0721 and LM-0725 are available in ePortal for review.
Phase 2 ISE 01 4 Unit 1 and Unit 2 - Complete The NRC staff reviewed the Closed information provided in the 6-Licensee to demonstrate that The wetwell vent has been designed and month updates and on the
[Staff evaluation to be containment failure as a result installed to meet NEI 13-02 Rev 1 ePortal.
included in SE Sections of overpressure can be guidance, which will ensure that it is 4.1 and 4.2]
prevented without a drywell adequately sized to prevent containment The wetwell vent was designed vent during severe accident overpressure under severe accident and installed to meet NEI 13-02 conditions.
conditions.
Revision 1 guidance and is sized to prevent containment The SAWM strategy will ensure that the overpressure under severe wetwell vent remains functional for the accident conditions (see Phase 1 period of sustained operation. LGS will ISE Open ltem-2 above).
follow the guidance (flow rate and timing)
Limerick will follow the guidance for SAWA/SAWM described in BWROG-(flow rate and timing) for TP-15-008 and BWROG-TP-15-011.
SAWA/SAWM described in These documents have been posted to BWROG-TP-15-008, "Severe the ePortal for NRC staff review. The Accident Water Addition Timing",
wetwell vent will be opened prior to and BWROG-TP-15-011 "Severe exceeding the PCPL value of 60 psig.
Accident Water Management".
Therefore, containment over The wetwell be opened prior to pressurization is prevented without the exceeding the PCPL value of 60 need for a drywell vent.
psig.
The evaluations noted in BWROG-TP-15-008 demonstrates adding water to the reactor vessel within 8-hours of the onset of the event will limit the peak containment drywell temperature significantly reducing the possibility of containment failure due to temperature.
Drywell pressure can be controlled by venting the suppression chamber through the suppression pool.
The evaluations noted in BWROG-TP-15-011 demonstrates that starting water addition at a high rate of flow and throttling after approximately 4-hours will not increase the suppression pool 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 permit venting to maintain containment below the lower of PCPL or of design pressure.
No follow-up questions.
Phase 2 ISE 01 5 Unit 1 and 2 - Complete The NRC staff reviewed the Closed information provided in the 6-Licensee shall demonstrate Using Figure 2.1. C from the combined month updates and on the
[Staff evaluation to be how the plant is bounded by Phases 1 and 2 OIP, compare the ePortal.
included in SE Section the reference plant analysis reference plant parameters to the plant 4.2.1.1]
that shows the SAWM strategy specific parameters.
The reference plant has a Torus is successful in making it freeboard of 525,000 gallons.
unlikely that a drywell vent is Reference Plant:
Limerick has a Torus freeboard of needed.
1,104,572 gallons. Both the Torus free board volume is 525,000 reference plant and Limerick gallons assume SAWA flow of 500 gallons per minute (gpm) starting SAWA flow is 500 GPM at 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> at 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />. Both the reference followed by 100 GPM plant and Limerick reduces SAWA flow to 100 gpm at 12 LGS:
hours. BWROG TP-15-011 report confirmed, that the Mark I (and Suppression Pool freeboard volume is Mark II) fleet is bounded by the 147,670ft3 (1,104,572 gallons) reference plant analyses. This study addressed how suppression SAWA flow is 500 GPM at 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> pool level control could be followed by 100 GPM from 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> to achieved in a manner that 168 hours0.00194 days <br />0.0467 hours <br />2.777778e-4 weeks <br />6.3924e-5 months <br />.
maintains long-term function of the wetwell vent, and determined The above parameters for LGS compared if there would be adverse effects to the reference plant that determine by controlling (limiting) flow rate.
success of the SAWM strategy The study concludes that plants demonstrate that the reference plant with Mark I and Mark II values are bounding. Therefore, the containments, with injection into SAWM strategy implemented at LGS the RPV, can maintain makes it unlikely that a drywell vent is containment cooling and preserve needed to prevent containment the wetwell vent without a plant overpressure related failure specific analysis. The evaluation bounds the parameters at LGS.
LGS plans to follow this strategy and is bounded by the conclusions of the BWROG evaluation.
The NRC staff reviwed the parameters from the reference plant to those of Limerick. The staff concurs that it is unlikely the suppression chamber HCVS could become blocked leading to a successful SAWA/SAWM strategy. Therefore, it is unlikely a drywell vent would be required to maintain containment integrity.
No follow-up questions.
Phase 2 ISE 01 6 Complete.
The NRC staff reviewed the Closed information provided in the 6-Licensee to demonstrate that This communication method is the same month updates and on the
[Staff evaluation to be there is adequate as accepted in Order EA-12-049. These ePortal.
included in SE Section communication between the items will be powered and remain 4.1]
MCR and the operator at the powered using the same methods as The communication methods are FLEX pump during severe evaluated under EA-12-049 for the period the same as accepted in Order accident conditions.
of sustained operation, which may be EA-12-049.
longer than identified for EA-12-049.
No follow-up questions.
Communication will be via the plant radio system if available. If the radio system is not available, the Plant page system can be used. The page system was modified for FLEX to include a UPS that can be manually aligned to repower the system.
(Reference AR 2492527-42)
Phase 2 ISE 01 7 Unit 1 and Unit 2 - Complete The NRC staff reviewed the Closed information provided in the 6-Licensee to demonstrate the For locations outside the Reactor Building month updates and on the
[Staff evaluation to be SAWM flow instrumentation between 7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br /> and 7 days when SAWA ePortal.
included in SE Sections qualification for the expected is being utilized, Limerick Generating 4.1.1.3 and 4.2.1.3]
environmental conditions.
Station performed evaluation of expected EC 622673 discusses the SAWM temperatures, humidity and the dose flow instrumentation qualification.
rates and determined them to be The NRC staff found through acceptable. (Reference EC 622673).
engineering judgement that the accuracy of the flow meter and SAWA Pum~ Flow Instrument the environmental qualifications Qualification related to the performance of the flow meter meets the intent of 37 to 1246 GPM, 32 to 140 °F fluid Order EA-13-109.
temperature, 14 to 122 °F Instrument Electronics*, 275 PSI maximum No follow-up questions.
Ex~ected SAWA Parameter Qualification Range 100 to 500 GPM, 32 to 95 °F fluid temperature, 0 to 100 °F Ambient air temperature, 239.7 PSI maximum
- Below 14°F, the LCD may become sluggish or unresponsive; however, will continue to measure and function to at least -4 °F. (Reference MS2500-DataSheet).
MS2500-DataSheet and EC 622673 is available in ePortal for review.
- via email OFFICE NRR/DLP/PBEB/PM NRR/DLP/PBMB/LA NRR/DLP/PBEB/BC(A)* NRR/DLP/PBEB/PM NAME RAuluck Slent BTitus RAuluck DATE 5/23/18 5/21/18 5/25/18 5/29/18