W3F1-2023-0018, Updated Final Supplemental Response to NRC Generic Letter 2004-02

From kanterella
Jump to navigation Jump to search
Updated Final Supplemental Response to NRC Generic Letter 2004-02
ML23089A247
Person / Time
Site: Waterford Entergy icon.png
Issue date: 03/30/2023
From: Couture P
Entergy Operations
To:
Office of Nuclear Reactor Regulation, Document Control Desk
References
W3F1-2023-0018, GL-2004-02
Download: ML23089A247 (1)
v • d • e


Text

Phil Couture Senior Manager Fleet Regulatory Assurance - Licensing 601-368-5102 W3F1-2023-0018 March 30, 2023 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001

Subject:

Updated Final Supplemental Response to NRC Generic Letter 2004-02 Waterford Steam Electric Station, Unit 3 NRC Docket No. 50-382 Renewed Facility Operating License No. NPF-38 The purpose of this submittal is to provide the Entergy Operations, Inc. (Entergy) final supplemental response for Waterford Steam Electric Station, Unit 3 (Waterford 3) to Generic Letter (GL) 2004-02, dated September 13, 2004, "Potential Impact of Debris Blockage on Emergency Recirculation during Design Basis Accidents at Pressurized-Water Reactors."

On May 16, 2013, Entergy submitted a letter of intent (Reference 1) per SECY-12-0093, "Closure Options for Generic Safety Issue - 191, Assessment of Debris Accumulation on Pressurized-Water Reactor Sump Performance," indicating Waterford 3 would pursue Closure Option 2 - Deterministic of the SECY recommendations (refinements to evaluation methods and acceptance criteria). The final outstanding issue for Waterford 3 with respect to GL 2004-02 is the in-vessel downstream effects evaluation, which addresses that long-term core cooling (LTCC) can be adequately maintained for all postulated accident scenarios that require sump recirculation.

The in-vessel downstream effects evaluation has been completed for Waterford 3. The information documented in the enclosure to this letter satisfies two of the three GSI-191 commitments identified in References 2 and 3. The remaining commitment to update the Waterford 3 licensing basis will be completed within 90 days of receiving NRC acceptance of this updated final supplemental response to GL 2004-02.

Should you have any questions or require additional information, please contact Leia Milster, Regulatory Assurance Manager, Waterford 3, at 504-739-6250.

This letter contains no new commitments.

Entergy Operations, Inc. 1340 Echelon Parkway, Jackson, MS 39213

W3F1-2023-0018 Page 2 of 2 I declare under penalty of perjury; that the foregoing is true and correct.

Executed on March 30, 2023.

Respectfully, Philip Digitally signed by Philip Couture Couture Date: 2023.03.30 11:33:41 -05'00' Phil Couture PC/mmz

Enclosure:

Waterford 3 Updated Final Supplemental Response to Generic Letter 2004-02

References:

1) Entergy Operations, Inc. (Entergy) letter to U. S. Nuclear Regulatory Commission (NRC), "Closure Option for Generic Safety Issue - 191,"

(ML13137A133), dated May 16, 2013.

2) Entergy letter to NRC, "Commitment Change Notification for Generic Safety Issue - 191 and Generic Letter 2004-02," (ML20329A519), dated November 24, 2020.
3) Entergy letter to NRC, "Commitment Change Notification for Generic Safety Issue - 191 and Generic Letter 2004-02," (ML22355A140), dated December 20, 2022.

cc: NRC Region IV Regional Administrator NRC Senior Resident Inspector - Waterford Steam Electric Station, Unit 3 NRC Project Manager Waterford Steam Electric Station, Unit 3

Enclosure W3F1-2023-0018 WATERFORD 3 UPDATED FINAL SUPPLEMENTAL RESPONSE TO GENERIC LETTER 2004-02

W3F1-2023-0018 Enclosure Page 1 of 21 TABLE OF CONTENTS 1.0 OVERALL COMPLIANCE .................................................................................................. 2 1.1 Overview of Waterford 3 Resolution to GL 2004-02 ....................................................... 2 1.2 Correspondence Background ......................................................................................... 3 1.3 General Plant System Description .................................................................................. 5 1.4 General Description of Sump Strainers .......................................................................... 5 2.0 GENERAL DESCRIPTION AND SCHEDULE FOR CORRECTIVE ACTIONS ................. 6 3.0 SPECIFIC INFORMATION FOR REVIEW AREAS............................................................ 7 3.n Downstream Effects - Fuel and Vessel .......................................................................... 7 3.p Licensing Basis ............................................................................................................. 19

4.0 REFERENCES

................................................................................................................. 19

W3F1-2023-0018 Enclosure Page 2 of 21 WATERFORD 3 UPDATED FINAL SUPPLEMENTAL RESPONSE TO GENERIC LETTER 2004-02 1.0 OVERALL COMPLIANCE NRC Issue:

Provide information requested in GL 2004-02, "Requested Information," Item 2(a) regarding compliance with regulations. That is, provide confirmation that the Emergency Core Cooling System (ECCS) and Containment Spray (CS) recirculation functions under debris loading conditions are or will be in compliance with the regulatory requirements listed in the Applicable Regulatory Requirements section of this generic letter. This submittal should address the configuration of the plant that will exist once all modifications required for regulatory compliance have been made and this licensing basis has been updated to reflect the results of the analysis described above.

Entergy Response:

In accordance with SECY-12-0093 and as identified in Entergy Operations, Inc. (Entergy) letter to the NRC dated May 16, 2013 (Reference 1), Waterford 3 elected to pursue GSI-191 Closure Option 2 - Deterministic and identified in-vessel downstream effects as the last outstanding issue. Topical Report (TR) WCAP-17788-P, Rev. 1 (Reference 2) provides evaluation methods and results to address in-vessel downstream effects. As discussed in NRC Memorandum, "Technical Evaluation Report of In-Vessel Debris Effects," (Reference 3), the NRC staff has performed a detailed review of WCAP-17788-P. Although the NRC staff did not issue a Safety Evaluation for WCAP-17788, as discussed further in NRC Memorandum, "U.S. Nuclear Regulatory Commission Staff Review Guidance for In-Vessel Downstream Effects Supporting Review of Generic Letter 2004-02 Responses" (Reference 4), the NRC expects that many of the methods developed in the TR can be used by Pressurized Water Reactor (PWR) licensees to demonstrate adequate long-term core cooling (LTCC). Completion of the analyses demonstrates compliance with 10 CFR 50.46, "Acceptance criteria for emergency core cooling systems for light-water nuclear power plants," (b)(5), "Long-term cooling," as it relates to in-vessel downstream debris effects for Waterford 3.

This enclosure follows the NRC review guidance (Reference 4) and PWROG-16073-P, "TSTF-567 Implementation Guidance, Evaluation of In-Vessel Debris Effects, Submittal Template for Final Response to Generic Letter 2004-02 and FSAR Changes" (Reference 5), to describe the fiber penetration testing and in-vessel analysis, establish in-vessel acceptance criteria, and demonstrate that the criteria are met for Waterford 3. This enclosure is a supplement to Entergy's previous submittals for Waterford 3 on Generic Letter (GL) 2004-02.

1.1 Overview of Waterford 3 Resolution to GL 2004-02 On February 29, 2008, Entergy submitted a Supplemental Response to GL 2004-02 for Waterford 3 (Reference 6). By letters dated October 23, 2008 (Reference 7) and November 23, 2010 (Reference 8), Entergy submitted a Final Supplemental Response and Response to Request for Additional Information, respectively, for Waterford 3 regarding the GL 2004-02 response that had not been completed at the time of the February 2008 response.

The content and level of detail provided were consistent with the NRC guidance (Reference 9).

W3F1-2023-0018 Enclosure Page 3 of 21 In Reference 8, Entergy committed to address the resolution of downstream in-vessel effects for Waterford 3 following the issuance of revised WCAP-16793, "Evaluation of Long-Term Cooling Considering Particulate, Fibrous and Chemical Debris in the Recirculating Fluid,"

(Reference 10) and the associated NRC Safety Evaluation Report. By Reference 1, Entergy identified that Waterford 3 intended to follow the resolution strategy proposed by the PWROG for establishing in-vessel fiber limits, with the intent of the PWROG program to improve upon the WCAP-16793 acceptance limit. In addition, Reference 1 included a summary of the actions completed to address GL 2004-02 and a summary of margins and conservatisms for completed and on-going actions for GL 2004-02. By Reference 1, Entergy made several commitments to achieve closure of GSl-191 and to address Generic Letter (GL) 2004-02. Based upon the changes made to the PWROG program schedule and the issuance of Reference 2 and Reference 5, Entergy made subsequent revisions to these commitments per References 11-15.

The changes that were implemented and identified in the Waterford 3 responses referenced above remain valid and no further changes are being made to address in-vessel downstream effects.

The Waterford 3 Supplemental Responses to GL 2004-02 also identified some of the conservatisms in the approach to resolving GSI-191. The conservatisms identified in the Waterford 3 Supplemental Responses remain valid and some of the conservatisms in the in-vessel downstream effects analysis are as follows:

All fiber that reaches the reactor was conservatively assumed to accumulate at the reactor core inlet.

For the ECCS strainer, although the bottom surface of the bottom disk is perforated, it is partially occluded by supports and the plenum, so to maintain conservatism credit is not taken for this area.

Bypass testing measured the bypassed fiber quantity for a prototypical Waterford 3 ECCS strainer using test conditions that conservatively maximized fiber bypass.

1.2 Correspondence Background The following provides a listing of correspondence issued by the NRC or submitted by Entergy for Waterford 3 on GSI-191 and/or GL 2004-02.

Table 1 - Generic Letter 2004-02 Correspondence ADAMS Document Date Accession Document Number September 13, 2004 ML042360586 NRC GL 2004-02 March 3, 2005 ML050660261 First Response to GL-04-002 June 2, 2005 ML051660501 First NRC Request for Additional Information (RAI)

July 28, 2005 ML052140281 First RAI Response September 16, 2005 ML052630441 Second Response to GL 2004-02

W3F1-2023-0018 Enclosure Page 4 of 21 Table 1 - Generic Letter 2004-02 Correspondence (continued)

ADAMS Document Date Accession Document Number December 19, 2005 ML053550197 Additional Response to GL 2004-02 February 9, 2006 ML060390386 Second NRC RAI March 28, 2006 ML060870274 Alternative Approach for Responding to the NRC RAI Regarding GL 2004-02 November 29, 2006 ML063350052 GL 2004-02 Commitment Revision January 4, 2007 ML063460258 Alternative Approach for Responding to the NRC RAI Regarding GL 2004-02 November 14, 2007 ML073200095 Request for Extension of Completion Date for Corrective Actions Required by GL 2004-02 November 21, 2007 ML073110389 NRC Revised Content Guide December 10, 2007 ML073390065 Approval of Extension for GL 2004-02 Corrective Actions January 28, 2008 ML08140315 NRC Staff Audit Report on Results of Corrective Actions to Address GSI-191 GL 2004-02 February 29, 2008 ML080650614 Supplemental Response to GL 2004-02 May 12, 2008 ML081350231 Request for Extension of Completion Date for Resolution of GL 2004-02 May 22, 2008 ML081430271 Approval of Extension Request for GL 2004-02 October 23, 2008 ML083020551 Final Supplemental Response to GL 2004-02 September 22, 2009 ML092510124 Third NRC RAI May 18, 2010 ML101340061 Forthcoming Conference Call with Entergy to Discuss Draft Response on GL 2004-02 June 9, 2010 ML101530232 Summary of June 1, 2010 Conference Call with Entergy on Draft RAI Responses for GL 2004-02 November 23, 2010 ML103340117 Response to RAI Regarding Supplemental Response to GL 2004-02 February 9, 2011 ML110450255 GL 2004-02 Commitment Change Due to Deferral of Replacing the Steam Generators May 16, 2013 ML13137A133 Closure Option for GSI-191 June 30, 2015 ML15181A393 Commitment Change for GSI-191 December 15, 2016 ML16350A459 Commitment Change for GSI-191 November 24, 2020 ML20329A519 Commitment Change for GSI-191 and GL 2004-02 December 16, 2021 ML21350A358 Commitment Change for GSI-191 and GL 2004-02 December 20, 2022 ML22355A140 Commitment Change for GSI-191 and GL 2004-02

W3F1-2023-0018 Enclosure Page 5 of 21 1.3 General Plant System Description The Waterford 3 Nuclear Steam Supply System (NSSS) is a PWR designed by Combustion Engineering (CE) Incorporated. The Reactor Coolant System (RCS) is arranged as two closed loops connected in parallel to the reactor vessel. Each loop consists of one outlet (hot) pipe, one steam generator, two inlet (cold) pipes and two pumps. An electrically heated pressurizer is connected to one of the loops and a safety injection line is connected to each of the four inlet legs.

The ECCS [or Safety Injection System (SIS)] is designed to provide core cooling in event of a loss of coolant accident (LOCA) or a main steam line break (MSLB). The SI system is arranged with two independent redundant trains, each functionally identical to the other. The SI system is activated by the Safety Injection Actuation Signal (SIAS) which is initiated by either low pressurizer pressure or high containment pressure. The SIAS automatically starts the two High Pressure Safety Injection (HPSI) pumps (Trains A and B) and the two Low Pressure Safety Injection (LPSI) pumps (Trains A and B) and opens the motor operated valves that provide a flow path from the discharge of these pumps to the RCS. The LPSI and HPSI pumps initially take suction from the Refueling Water Storage Pool (RWSP) and deliver borated water to the RCS for removal of heat from the reactor core. When a low level is sensed in the RWSP, the recirculation mode is initiated by the Recirculation Actuation Signal (RAS). At this time the HPSI pump suction is diverted to the SI sump and the LPSI pumps are stopped.

The Containment Spray (CS) System (CSS) is designed to remove heat from the containment atmosphere following a LOCA or MSLB inside containment. The CS is initiated by a containment spray actuation signal (CSAS). The CSAS results from the combination of a high-high containment pressure signal and a SIAS. In the initial mode of operation (Injection Mode), the CS is lined up so that the two CS pumps (Trains A and B) take suction from the RWSP and sprays the containment with borated water by pumping this water through the containment spray nozzles. When the water level in the RWSP falls to a predetermined level, a RAS is generated which shifts suction of the CS pumps to the SI sump by opening the sump outlet isolation valves.

The SIS sump is a large collecting reservoir designed to provide an adequate supply of water to the CSS and SIS during the recirculation mode. Two separate inlets, one for each redundant half of the ECCS and CSS, are provided. The inlets are separated from each other by a partition screen.

1.4 General Description of Sump Strainers As stated in Waterford 3 GL 2004-02 responses (References 6, 7, and 8), the Waterford 3 System sump strainer assembly is supplied by General Electric (GE) consisting of plenum and GE modular stacked disk strainers. The Modular Strainer employs a series of vertically stacked disks surrounding an axial cavity. The module design was optimized to meet the needs of ECCS and CSS. The dimensions of the modules were adjusted to accommodate the debris loads and containment configurations. The Modular Strainer makes use of the GE Debris Plate.

The debris plate and the small pitch between disks allows the GE Modular Strainer to mitigate thin-bed effects. A thin-bed effect occurs from the formation of a high particulate content debris bed directly on the surface of the perforated plate, which causes higher head loss than if a thicker (but higher fiber content) debris bed were to form. The GE Debris Plate serves to disrupt the formation of the thin-bed and reduces head loss. The sump strainer consists of eleven (11)

W3F1-2023-0018 Enclosure Page 6 of 21 strainer modules mounted on top of the plenum. The modules are 40-inch square, each composed of 17 disks with the top disk having a solid plate. Perforated plates have 3/32-inch diameter holes staggered at 5/32-inch. The strainers prevent larger sized suspended particles from entering the sump. The 3/32-inch diameter hole was selected to avoid entrapment of particles in the fuel assembly spacer grids and to maximize the net positive suction head (NPSH) margin for HPSI and CS pumps. The sump is partitioned in half by a stainless steel grating plate attached to the sump floor and sides extending to the bottom of the plenum. The sump partition separates Train A and Train B with a stainless steel grating of 1" x 1/8" bars separated at 1-3/16". The grated partition will allow fluid mixing (including fine debris and particles) between the two (2) sump halves and not create separate screened in pump intakes.

The partition maintains a single strainer assembly/single sump design that is available to both trains. The strainers are mounted on a frame support structure that is bolted to the sump floor.

The strainers provide a total of 3699 ft2 of perforated plate surface area and 586.3 ft2 of circumscribed surface area.

2.0 GENERAL DESCRIPTION AND SCHEDULE FOR CORRECTIVE ACTIONS NRC Issue:

Provide a general description of actions taken or planned, and dates for each. For actions planned, reference approved extension requests or explain how regulatory requirements will be met as per "Requested Information" Item 2(b). That is, provide a general description of and implementation schedule for all corrective actions, including any plant modifications, that you identified while responding to this generic letter.

Entergy Response:

A summary of the actions that were completed by Entergy were provided in Reference 1.

These actions were fully described in References 6, 7, and 8. This final supplemental response addresses the remaining Waterford 3 commitments (listed below) as identified in References 13 and 15.

Any necessary replacement or remediation of insulation will be based on the guidance of PWROG-16073-P and will be completed by the third refueling outage following its approval.

After establishing a final determination of the scope of insulation replacement, remediation, or model refinements, Waterford 3 will submit a final updated supplemental response to support closure of GL 2004-02 for Waterford 3.

Waterford 3 will evaluate the current licensing basis following NRC acceptance of the final updated supplemental response for Waterford 3.

Entergy has determined that Waterford 3 does not require any new modifications or other remediation measures for the closure of GL 2004-02. The Waterford 3 Updated Final Safety Analysis Report will be updated to incorporate the in-vessel downstream effects analysis and conclusions (see Section 3.p of this Enclosure). There are no other outstanding corrective actions associated with GL 2004-02 for Waterford 3.

W3F1-2023-0018 Enclosure Page 7 of 21 3.0 SPECIFIC INFORMATION FOR REVIEW AREAS As stated in References 6, 7, and 8, Waterford 3 has addressed review areas 3.a through 3.m and 3.o. The remaining outstanding review areas, 3.n and 3.p, are addressed in this submittal.

3.n Downstream Effects - Fuel and Vessel NRC Issue:

The objective of the downstream effects, fuel, and vessel section is to evaluate the effects that debris carried downstream of the containment sump screen and into the reactor vessel has on core cooling Show that the in-vessel effects evaluation is consistent with, or bounded by, the industry generic guidance (WCAP-16793), as modified by NRC staff comments on that document. Briefly summarize the application of the methods. Indicate where the WCAP methods were not used or exceptions were taken, and summarize the evaluation of those areas.

Entergy Response:

As described in Entergy letter dated November 24, 2020 (Reference 13), Waterford 3 is following the implementation guidance provided by PWROG-16073-P (Reference 5). This guidance supports the use of TR WCAP-17788-P, Rev. 1 (Reference 2), which provides evaluation methods and results to address in-vessel downstream effects. As discussed in the NRC Technical Evaluation Report (Reference 3), the NRC staff has performed a detailed review of WCAP-17788-P. Although the NRC staff did not issue a Safety Evaluation for WCAP-17788-P, as discussed further in the NRC Staff Review Guidance (Reference 4), the NRC expects that many of the methods developed in the TR may be used by PWR licensees to demonstrate adequate LTCC. Entergy used methods and analytical results developed in WCAP-17788-P, Rev. 1 to address in-vessel downstream debris effects for Waterford 3 and has evaluated the applicability of the methods and analytical results from WCAP-17788-P, Rev. 1 for Waterford 3. As summarized in this response, post-accident LTCC is not challenged by accumulation of debris inside the reactor vessel at Waterford 3.

Waterford 3 Sump Strainer Fiber Penetration As provided for in PWROG-16073-P, there are three options for determining the amount of fibrous debris that penetrates (bypasses) the sump strainer. Entergy has completed plant-specific penetration testing to define the downstream debris source term for in-vessel effects. Strainer bypass testing was completed in 2010 for Waterford 3 (Reference 16). The fiber bypass characteristics of the strainers was measured by performing fiber bypass testing on a representative section (prototype) of the entire assembly.

The Waterford 3 bypass testing measured the bypassed fiber quantity for a prototypical Waterford 3 ECCS strainer using test conditions that conservatively maximized fiber bypass. A representative approach velocity was passed through a prototypical strainer, and fiber was added incrementally until the maximum plant nominal strainer fiber debris bed thickness was reached. Small amounts of fiber are more likely to pass through the perforated plate without building a debris bed as opposed to large fiber additions which could cover the entire perforated

W3F1-2023-0018 Enclosure Page 8 of 21 plate and filter out debris, thereby reducing bypass, so small incremental fiber additions simulate the most conservative scenario for strainer fiber bypass. Bypassed fiber was captured using downstream 5-micron filter bags via a 100% pass through alignment in the flow stream.

After all fiber was added to the test tank and the stabilization criteria were satisfied, the pumps were secured and the filter bags removed from the apparatus and dried. After drying, the filter bags were weighed and the weights compared to the pre-test weights to determine the mass of the bypassed fiber.

The results of the testing show that the maximum quantity of LOCA-generated fibrous debris that can bypass the Waterford 3 ECCS strainers after a LOCA is 27.34 lbm. This equates to approximately 57.1 grams per fuel assembly (g/FA). Additional description of the Waterford 3 penetration (bypass) testing and results is provided in the sections that follow.

Test Flume Design Fiber bypass testing was performed on a prototypical section of the sump strainer to measure the maximum fiber bypass quantity through the test strainer. The prototype section assured a 1:1 scaling ratio for test parameters. The prototypical strainer section was comprised of five (5) disks that were duplicates of the disks in the plant strainers, which allowed debris and flow to be scaled based on the ratio of numbers of disks in the test vs. the number of disks in the plant. The test strainer gross surface area was 84.1 ft². The test strainer had additional internal support bars, but this was a negligible difference and did not significantly affect the quantity of bypassed fiber. The top surface of the top disk and the bottom surface of the bottom disk were solid, so that the test article contained four (4) gaps total.

A diagram of a typical test tank instrumentation setup is illustrated in Figure 1. An isometric view of the test tank layout is shown in Figure 2. A photograph of the strainer bypass test article is shown in Figure 3.

The simulated plenum beneath the strainer created a no-flow "dead zone," and this area was isolated using plywood, sealing vinyl gasket material, and waterproof duct tape. Debris was not observed to transport into the dead zone during testing. A sparger system was used to aid in the suspension of the debris within the water by directing the pump discharge along the floor on the left side of the test tank. The sparger was installed to maximize debris suspension in the tank without disturbing the debris bed around the strainer. An electromechanical agitator (a modified trolling motor) was used in the deep portion of the tank to ensure all debris was suspended and able to transport to the test strainer. Additionally, manual stirring was used to resuspend significant fiber that settled around or on top of the test strainer.

W3F1-2023-0018 Enclosure Page 9 of 21 Figure 1 - Waterford 3 Hydraulic Test Tank Diagram Figure 2 - Isometric View of Strainer Test Module in Tank

W3F1-2023-0018 Enclosure Page 10 of 21 Figure 3 - Photograph of Waterford 3 Strainer Bypass Test Article Test Flow Rate The Waterford 3 fiber bypass test used a nominal flow rate of 152 gpm that simulated the plant perforated approach velocity to the test article. During testing, the measured flow rate ranged from 144 - 155 gpm while debris was present, although higher flow rates (~285 gpm) were used to purge air from the system. The water temperature was maintained above 80°F during the test, and ranged between 80° and 90°F.

Debris Preparation NUKON fines were the only debris added to the Waterford 3 bypass test. NUKON fines were used to represent plant NUKON fiber insulation and metal encapsulated insulation (MEI). The as-fabricated density of NUKON is 2.4 lbm/ft3 and the nominal fiber diameter is 7 microns.

The debris preparation procedure used produced the required size distribution and fiber fines that are easily transportable and readily disperse in the testing medium. All fiber fines were double-shredded with a leaf shredder and boiled for 10 minutes. Fiber fines were further processed by adding 4 gallons of water to 1/4 lbm of fiber and agitating with a paint stirrer for 4 minutes to ensure complete dispersion of fibers, and the fiber slurry was resuspended with similar agitation prior to introduction into the test tank. A photograph of prepared NUKON fiber from the bypass testing is included as Figure 4.

W3F1-2023-0018 Enclosure Page 11 of 21 Figure 4 - Prepared Bypass Test NUKON Fines Debris Introduction Debris was scaled for this test to yield a fiber bed thickness on the test strainer that is equal to the maximum possible post-LOCA fiber debris bed thickness on the plant strainer. Fiber was added to the tank in nine small additions to maximize fiber bypass. Since fiber bypass is the phenomenon of fiber passing through the holes in the perforated plate, small fiber additions tend to allow more fiber to pass through the strainer before a full fiber bed can form. Batches of fiber were added in 1/16" equivalent bed thicknesses for the first four additions, to a nominal fiber thickness of 1/4", at which point the fiber additions were increased to 1/8" equivalent thickness until the nominal plant maximum fiber bed thickness was reached. Fiber additions are included in the test matrix in Table 3. The water level was adjusted to 2.0 +/- 0.5 in. above the highest top surface of the strainer before the first debris addition, and the water level increased with the addition of debris. Since this test did not include air ingestion testing or near field settling and the water level only increased during the test, the water level was not a critical parameter after the initial debris was added.

W3F1-2023-0018 Enclosure Page 12 of 21 Table 3 - Test Matrix Nominal Fiber Nukon Flow Rate Test # Thickness Fines gpm (in.) (lbm)

WF3-4.1-BYP-B 152 0.000 0 WF3-4.2-BYP-F1 152 0.0625 1.05 WF3-4.3-BYP-F2 152 0.1250 1.05 WF3-4.4-BYP-F3 152 0.1875 1.05 WF3-4.5-BYP-F4 152 0.2500 1.05 WF3-4.6-BYP-F5 152 0.3750 2.10 WF3-4.7-BYP-F6 152 0.5000 2.10 WF3-4.8-BYP-F7 152 0.6250 2.10 WF3-4.9-BYP-F8 152 0.7500 2.10 WF3-4.10-BYP-F9 152 0.7744 0.41 TOTAL Quantity of Fiber Introduced to Test 13.01 lbm Transport Efficiency After each fiber addition, the test was continued for five tank turnovers after all visible fiber had been transported to the strainer, or for a minimum of ten total tank turnovers, whichever duration was longer. After the final fiber addition, the tank was allowed to circulate for fifteen tank turnovers before test termination.

At the completion of each fiber addition step in the test matrix, settled debris was also agitated manually to ensure that debris reached the strainer module and that no significant quantities of debris were allowed to settle in the tank environs. Manual agitation was continued only until further manual stirring had no noticeable effect on the system head loss or the amount of settled debris. Manual agitation was provided through use of a wooden oar and was conducted carefully to avoid disturbing the debris bed on the strainer module. Also, fibrous debris that had settled on the unperforated top of the top strainer was agitated manually and carefully using the oar to avoid disturbing the debris bed.

Capture/Quantification of Bypassed Debris The filter bags used to capture bypassed NUKON particles/fibers were 5-micron mesh size.

NUKON fibers typically have a diameter of 7 microns and typically have a much longer characteristic length, which facilitated high capture efficiencies. The capture efficiency of the filter bag is 90%. Before use the filters were prewashed to remove any loose material. The filter bags were dried and weighed before and after testing to calculate the amount of NUKON that was captured in the filter bags during the test.

Four filter bags were used during testing, two for capturing NUKON, one as spare to switch flow to if head loss approached the upper limit for the bags in the flow path, and one as a control.

However, the measured head loss across the filter bags never approached the maximum allowable per the test plan (8 psi), so only two bags were used to capture fiber, bags "A"

W3F1-2023-0018 Enclosure Page 13 of 21 and "B". The control filter bag was isolated prior to debris addition and was used to determine when the fiber-capture filter bags had completely dried after testing. All bags were dried together, and when the control filter bag post-test dry mass was nearly equal to the control filter bag pre-test dry mass (with margin allowed for minimal latent filtering), then the other filter bags were considered dry as well. The pre- and post-testing mass difference of the capture bags is equal to the mass of the captured (bypass) NUKON. The captured NUKON was saved for possible future analysis and characterization. Prior to testing, another set of 5-micron filter bags were used to completely filter out any 5-micron or larger latent debris that was present in the test tank and would have affected the post-test mass of the testing filter bags.

Bypass Test Results A plot of head loss and flow rate recorded during the test is included as Figure 5.

Figure 5 - WF3-BYP Head Loss and Flow Rate vs. Time A table of filter bag weights before and after testing, as well as the total mass of fiber bypass is included as Table 4.

The test objectives do not include the measurement of particulate debris bypass, and the presence of particulate in the debris load would preclude the accurate measurement of fiber bypass, thus no particulates were added during testing.

W3F1-2023-0018 Enclosure Page 14 of 21 Table 4 - Filter Bag Weights, Drying Times, and Mass of Fiber Collected Filter A Filter B Pre-Test Drying Time Mass Drying Time Mass (hr) (g) (hr) (g) 1st Weight 0 198.84 0 197.4 2nd Weight 49 198.03 49 196.78 3rd Weight 51 198.07 51 196.81 4th Weight 58 198.05 58 196.77 Filter A Filter B Post-Test Drying Time Mass Drying Time Mass (hr) (g) (hr) (g) 1st Weight 110 320.98 110 321.38 2nd Weight 114 320.94 114 321.33 3rd Weight 158 320.97 158 321.38 Collected Fiber Filter A Filter B Fiber Mass 122.92 g 124.61 g (per filter)

Total Fiber Mass 247.53 g Collected The bypass fraction is the portion of debris transported to the sump strainer that is not collected on the sump strainer, and instead passes through the sump strainer and is transported into either the CSS or reactor vessel. A bypass fraction of 4.66% was calculated by taking the total fiber mass collected (247.53 g) (Table 4), dividing by 0.9 to account for 90% capture efficiency, and dividing by the amount introduced to the test of 13.01 lbm (5901 g) (Table 3):

Bypass Fraction = 247.53 g / 0.9 / 5901 g = 0.0466 = 4.66%

Per calculation 2005-05500 (Reference 17), which determines the quantity of LOCA generated debris which reaches the SI sump screen for various postulated line breaks, it has been conservatively determined the fibrous debris amount that would be transported to the Waterford 3 SI Sump during a LBLOCA is 244.4 ft3. The equivalent mass of 244.4 ft3 of fiber is 586.6 lbm, based on the density of fiber of 2.4 lbm/ft3. The bypass fraction is applied to this value to show that the maximum quantity of LOCA-generated fibrous debris that can bypass the Waterford 3 ECCS strainers after a LOCA is 27.34 lbm.

Applicability to WCAP-17788 Methods and Analysis Results The NRC review guidance (Reference 4) provided four different paths that PWR licensees can use to resolve the issue based on the Alternate Flow Path (AFP) analysis in WCAP-17788-P, Rev. 1. Entergy chose to use the Box 4 path for the Waterford 3 resolution. Per Reference 4, it is necessary to confirm that Waterford 3 is within the key parameters of the WCAP-17788-P, Rev. 1 methods and analysis. Table 5 summarizes the comparison of key parameters values for in-vessel debris effects. Each of the key parameters is discussed in the sections that follow

W3F1-2023-0018 Enclosure Page 15 of 21 the table. Based on these comparisons, Waterford 3 is bounded by the key parameters and the WCAP-17788-P, Rev. 1 methods and results are applicable (Reference 25).

Table 5 - Key Parameter Values for In-Vessel Debris Effects WCAP-17788-P, Rev. 1 Waterford 3 Parameter Value Value NSSS Design Various CE Fuel Type Westinghouse 16x16 Various Next Generation Fuel (NGF)

Minimum Chemical Precipitate 333 minutes Time (tblock from WCAP-17788-P, 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> (tchem)

Rev. 1, Volume 1, Table 6-1)

Maximum Hot Leg Switchover N/A 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> after accident (HLSO) Time Maximum Core Inlet Fiber Load Volume 1, Table 6-3 57.1 g/FA for HLB Maximum In-Vessel Fiber Load Volume 1, Section 6.4 57.1 g/FA for HLB Minimum Sump Switchover 20 minutes 26.9 minutes (SSO) Time Maximum Rated Thermal Power 3458 MWt 3716 MWt Maximum AFP Resistance Volume 4, Table 6-3 Volume 4, Table RAI-4.3-8 Minimum ECCS Flow per Fuel 3.8 - 11.4 gpm/FA 9.1 gpm/FA Assembly Comparison of tchem with HLSO Time and tblock For Waterford 3, chemical precipitation (tchem) was shown to occur after the latest HLSO time and after the time that complete core inlet blockage can be tolerated, which is defined in WCAP-17788-P as tblock.

Predicted chemical precipitation timing from WCAP-17788-P, Rev. 1, Volume 5 testing and the specific test group considered to be representative of the plant: Chemical precipitation timing is dependent on the plant buffer, sump pool pH, volume and temperature, and debris types and quantities. Table 6 summarizes the key chemical precipitation parameters and current values for Waterford 3 for comparison with the Test Group 33 parameters from WCAP-17788-P, Rev. 1, Volume 5. The Westinghouse proprietary Test Group 33 parameters are not shown. Based on the comparison, Test Group 33 is representative of Waterford 3 and the predicted chemical precipitation timing (tchem) is 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

Confirmation that chemical effects will not occur earlier than latest time to implement Boric Acid Precipitation (BAP) mitigation measures - Waterford 3 performs injection realignment (HLSO, referred to at Waterford 3 as simultaneous hot and cold leg injection) to mitigate the potential for boric acid precipitation no later than 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> after the accident, which is less than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> (tchem).

W3F1-2023-0018 Enclosure Page 16 of 21 WCAP-17788-P tblock value for the RCS design category: Waterford 3 is a CE plant. Based on WCAP-17788-P, Rev. 1, Volume 1, Table 6-1, tblock for Waterford 3 is 333 minutes.

Table 6 - Key Parameter Values for Chemical Precipitation Timing Parameter Waterford 3 Value Reference Buffer TSP 26 pH 8.1 26 Minimum Sump Volume 46,525 ft3 23 Max Sump Pool Temperature 212.9 °F 24 CalSil 0 21 E-glass (Nukon, MEI, latent) (Note 1) 832.8 ft 3 21 Silica (Min-K, Microtherm) 4.6 ft 3 21 Mineral Wool 0 21 Aluminum Silicate 0 21 Concrete (exposed) (Note 1) 80,748 ft 2 22 Interam 0 21 Aluminum (Note 2) 65.65 ft 2 22 Galvanized Steel/Zinc (Notes 1, 3) Not Determined 22 NOTES:

(1) Per WCAP-17788 Volume 5 Table 7-6, Galvanized steel/zinc area, concrete surface area, and insulation material mass have no effect on tchem.

(2) Aluminum exposed to containment spray plus aluminum below flood elevation. Per WCAP-17788 Volume 5 Table 7-6, decreasing plant aluminum area per coolant volume relative to the test aluminum area per coolant volume decreases the risk of precipitation and increases tchem.

(3) Per WCAP-17788 Volume 5, The galvanized steel was calculated from the total amount of submerged galvanized steel plus submerged untopcoated zinc coating. The potential source of input for Test Group 33 from Waterford 3 could not be determined. Submerged values are not determined by Reference 22.

Comparison of Waterford 3 In-Vessel Fiber Load with WCAP-17788-P Limit The maximum amount of fiber that may arrive at the core inlet for Waterford 3 during a hot leg break (HLB) exceeds the core inlet fiber limit but is less than the total in-core fiber limit presented in WCAP-17788-P, Rev. 1.

Fuel Design: The Waterford 3 reactor incorporates a 16x16 fuel assembly design. The core consists entirely of assemblies of the Westinghouse Next Generation Fuel (NGF) design.

WCAP-17788-P, Rev. 1 core inlet fiber limit: Waterford 3 is a CE-designed NSSS and uses 16x16 NGF fuel supplied by Westinghouse. The "Acceptable Core Inlet Fiber Load" given in Table 6-3 of WCAP-17788-P Rev. 1, Volume 1 is applicable. However, the 16x16 NGF fuel has a different fuel assembly pitch than that used to scale the debris loads in Table 6-3 and therefore, a scaling factor (Rm) defined in Step 8 in Section 6.5.5 of WCAP-17788-P Rev. 1, Volume 1 is required to adjust the core inlet fiber load. Using the 16x16 NGF fuel assembly pitch given in Table RAI-1.1-1 in Appendix B of WCAP-17788-P Rev. 1, Volume 1, a scaling factor of 0.933 is used to adjust the "Acceptable Core Inlet Fiber Load" given in Table 6-3 of WCAP-17788-P, Rev. 1, Volume 1.

W3F1-2023-0018 Enclosure Page 17 of 21 WCAP-17788-P, Rev. 1 total in-core fiber limit: The total in-core fiber limit is in Section 6.4 of WCAP-17788-P, Rev. 1, Volume 1.

Waterford 3 HLB core inlet fiber load: The maximum core inlet fiber load during a HLB for Waterford 3 is 57.1 g/FA. Waterford 3 conservatively assumes that all fibrous debris calculated to penetrate the strainer reaches the reactor vessel. Per the NRC review guidance (Reference 4), the flow split between the core inlet and AFPs was not credited. All the fiber that reaches the reactor is assumed to accumulate at the core inlet.

Per the NRC review guidance (Reference 4, Appendix B), the debris bed at the core inlet will not be uniform due to the variations in flow velocities at the core inlet; therefore, it will take more debris than determined by WCAP-17788-P to result in activation of the AFPs. As described in WCAP-17788-P, provided the total amount of fiber to the RCS remains less than or equal to the total in-core fiber limit, core cooling will be assured. Therefore, debris amounts above the WCAP-17788-P core inlet thresholds are acceptable provided the total amount of debris reaching the RCS is less than or equal to the total in-core fiber limit. For Waterford 3, the maximum quantity of fiber predicted to reach the reactor core (57.1 g/FA) is lower than the WCAP-17788-P total in-core fiber limit. As a result, the accumulation of fiber inside the reactor core would not challenge LTCC.

Comparison of Waterford 3 SSO Time with that Assumed in WCAP-17788-P The earliest SSO time for Waterford 3 is greater than that assumed in the WCAP-17788-P analysis.

Waterford 3 SSO time: The earliest possible SSO time (time to RAS) for Waterford 3 is 1611.86 seconds (26.9 minutes).

WCAP-17788-P, Rev. 1 analysis assumed SSO time: The SSO time assumed in the WCAP-17788-P analysis is 20 minutes (Volume 4, Table 6-3).

Comparison of Waterford 3 Reactor AFP Resistance with that Assumed in WCAP-17788-P The Waterford 3 AFP resistance is less than the analyzed value in WCAP-17788-P; therefore, the Waterford 3 AFP resistance is bounded by the resistance applied to the AFP analysis.

Waterford 3 AFP resistance: The Proprietary Waterford 3 specific AFP resistance is provided in Table RAI-4.3-8 of WCAP-17788-P, Rev. 1, Volume 4 as "Total Unadjusted K/A2 (ft-4)."

AFP resistance assumed in WCAP-17788-P: Waterford 3 is a CE plant. The Proprietary analyzed AFP resistance is provided in Table 6-3 of WCAP-17788-P Rev. 1, Volume 4 as "Barrel/Baffle Total K/A2 (ft-4)" for the Max Resistance Cases.

W3F1-2023-0018 Enclosure Page 18 of 21 Comparison of Maximum Thermal Power with that Assumed in WCAP-17788-P The Waterford 3 rated thermal power is greater than the analyzed power; therefore, this parameter is not bounded by the WCAP-17788-P, Rev. 1 analysis. Although the Waterford 3 rated thermal power is greater than the analyzed power, there is sufficient flow through the AFP to adequately remove decay heat. This is demonstrated because the Proprietary Waterford 3 specific AFP resistance provided in Table RAI 4.3-8 of WCAP-17788-P Rev. 1, Volume 4 as "total Adjusted K/A2 (ft-4)" is less than the analyzed value in WCAP-17788-P.

Waterford 3 rated thermal power: Waterford 3 has a rated thermal power of 3716 megawatts thermal (MWt). Waterford 3 is a CE design.

Thermal power assumed in WCAP-17788-P: As provided in WCAP-17788-P, Rev. 1, Volume 4, Table 6-3, the analyzed thermal power for the CE plants is 3458 MWt.

The NRC guidance (Reference 4) addresses the scenario where one or more of the key parameters are not satisfied by incremental amounts by offsetting unbounded parameters with plant-specific conservatisms. Based on the NRC guidance and PWROG-16073-P, it is appropriate to use the margin available in the Waterford 3 AFP resistance to offset the rated thermal power.

The plant-specific AFP resistance used in the AFP resistance comparison for Waterford 3 is the "Total Unadjusted K/A2 (ft-4)" from Table RAI-4.3-8 (for CE plants) in Appendix A of WCAP-17788-P Rev. 1, Volume 4. However, the AFP resistance and core power are linked as described in WCAP-17788-P RAI 4.2. A plant with higher power will require more flow through the AFP to adequately remove decay heat compared to a plant with lower power. The "Total Adjusted K/A2 (ft-4)" accounts for the difference in thermal power between Waterford 3 and that assumed in WCAP-17788-P. Comparing the value of "Total Adjusted K/A2" from Table RAI-4.3-8 for Waterford 3 to the "Barrel/Baffle Total K/A2" used in the model provides a source of margin in AFP resistance that demonstrates conservatism.

Comparison of Waterford 3 ECCS Flow Rate with that Analyzed in WCAP-17788-P The Waterford 3 ECCS flow per FA is within the range of flow rates analyzed in WCAP-17788-P, Rev. 1.

Waterford 3 ECCS flow rate: The Waterford 3 ECCS recirculation flow configuration used by the limiting in-vessel analysis (Reference 17) includes two HPSI pumps supplying flow to the cold legs at a flowrate of 985 gpm per pump. The total flow rate delivered to the reactor vessel is 1970 gpm from two HPSI pumps. As a result, the Waterford 3 ECCS flow rate per FA utilized in the limiting in-vessel analysis is 9.1 gpm/FA.

ECCS flow rates analyzed in WCAP-17788-P: For CE plants, the analyzed ECCS flow rate is 3.8 - 11.4 gpm/FA, as shown in Table 6-3 of WCAP-17788-P Rev. 1, Volume 4.

W3F1-2023-0018 Enclosure Page 19 of 21 3.p Licensing Basis NRC Issue:

The objective of the licensing basis section is to provide information regarding any changes to the plant licensing basis due to the sump evaluation or plant modifications.

Provide the information requested in GL 04-02 Requested Information Item 2(e) regarding changes to the plant licensing basis. The effective date for changes to the licensing basis should be specified. This date should correspond to that specified in the 10 CFR 50.59 evaluation for the change to the licensing basis.

Entergy Response:

The Waterford 3 licensing basis will be changed in accordance with the requirements of 10 CFR 50.71(e) to incorporate the results of the reactor in-vessel downstream effects evaluation into the Waterford 3 licensing basis within 90 days of receiving NRC acceptance of the updated final supplemental response to the GL.

4.0 REFERENCES

1. Entergy letter to NRC, "Closure Option for Generic Safety Issue - 191," (ML13137A133),

dated May 16, 2013.

2. Westinghouse Electric Company Topical Report WCAP-17788-P, Revision 1, "Comprehensive Analysis and Test Program for GSI-191 Closure (PA-SEE-1090),"

dated December 2019.

3. NRC Memorandum from V. G. Cusumano to M. Gavrilas, "Technical Evaluation Report of In-Vessel Debris Effects," (ML19178A252), dated June 13, 2019.
4. NRC Memorandum from V. G. Cusumano to J. E. Marshall, "U.S. Nuclear Regulatory Commission Staff Review Guidance for In-Vessel Downstream Effects Supporting Review of Generic Letter 2004-02 Responses," (ML19228A011), dated September 4, 2019.
5. PWROG Topical Report PWROG-16073-P, Revision 0, "TSTF-567 Implementation Guidance, Evaluation of In-Vessel Debris Effects, Submittal Template for Final Response to Generic Letter 2004-02 and FSAR Changes," dated February 28, 2020.
6. Entergy letter to NRC, "Supplemental Response to NRC Generic Letter 2004-02 Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized-Water Reactors", (ML080650614), dated February 29, 2008.
7. Entergy letter to NRC, "Final Supplemental Response to NRC Generic Letter 2004-02 Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized-Water Reactors," (ML083020551), dated October 23, 2008.

W3F1-2023-0018 Enclosure Page 20 of 21

8. Entergy letter to NRC, "Response to Request for Additional Information Regarding Final Supplemental Response to Generic Letter 2004-02, Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized-Water Reactors," (ML103340117), dated November 23, 2010.
9. NRC letter from W. H. Rutland to A. Pietrangelo, "Revised Content Guide for Generic Letter 2004-02 Supplemental Responses," (ML073110389), dated November 21, 2007.
10. Westinghouse Electric Company Topical Report WCAP-16793-NP-A, Rev. 2, "Evaluation of Long-Term Cooling Considering Particulate, Fibrous and Chemical Debris in the Recirculation Fluid," (ML13084A161, package includes NRC Safety Evaluation Report), dated July 2013.
11. Entergy letter to NRC, "Commitment Change Notification for Generic Safety Issue-191,"

(ML15181A393), dated June 30, 2015.

12. Entergy letter to NRC, "Commitment Change Notification for Generic Safety Issue-191,"

(ML16350A459), dated December 15, 2016.

13. Entergy letter to NRC, "Commitment Change Notification for Generic Safety Issue-191 and Generic Letter 2004-02," (ML20329A519), dated November 24, 2020.
14. Entergy letter to NRC, "Commitment Change Notification for Generic Safety Issue-191 and Generic Letter 2004-02," (ML21350A358), dated December 16, 2021.
15. Entergy letter to NRC, "Commitment Change Notification for Generic Safety Issue-191 and Generic Letter 2004-02," (ML22355A140), dated December 20, 2022
16. Waterford 3 Engineering Report WF3-ME-10-00007, "Waterford 3 Strainer Fiber Bypass Test Report (ALION-CAL-ENT-7849-11)," Revision 1, dated March 28, 2023.
17. Waterford 3 Calculation 2005-05500, "Post-LOCA Debris Transport, Head Loss Across Safety Injection Sump Screen, and NPSH Evaluation for Resolution of GSI-191,"

Revision 4, dated March 26, 2013.

18. NRC Generic Letter 2004-02, "Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized-Water Reactors,"

(ML042360586), dated September 13, 2004.

19. NRC Memorandum from R. V. Furstenau to H. K. Nieh, "Closure of Generic Issue GI-191, Assessment of Debris Accumulation on PWR Sump Performance,"

(ML19203A303), dated July 23, 2019.

20. NRC Policy Issue SECY-12-0093, "Closure Options for Generic Safety Issue - 191, Assessment of Debris Accumulation on Pressurized-Water Reactor Sump Performance,"

dated July 9, 2012.

21. Waterford 3 Calculation 2004-07780, "Debris Generation Due to LOCA within Containment for Resolution of GSI-191," Revision 5, dated March 26, 2013.

W3F1-2023-0018 Enclosure Page 21 of 21

22. Waterford 3 Calculation ECC04-006, "Tracking Containment Net Free Volume, Passive Heat Sink Capacity and Aluminum and Zinc Inventory", Revision 7, dated August 31, 2017.
23. Waterford 3 Calculation MNQ6-4, "Water Levels Inside Containment," Revision 3, dated December 17, 2008.
24. Waterford 3 Calculation ECS07-001, "Post LOCA Safety Injection Sump Minimum and Maximum Temperature Profiles for GSI-191 Support," Revision 0, dated November 7, 2007.
25. Waterford 3 Calculation ECM23-001, "Waterford 3 Reactor In-Vessel Debris Effects Evaluation for GL 2004-02," Revision 0, dated March 28, 2023.
26. Waterford 3 Calculation ECS96-013, "Post LOCA Safety Injection Sump TSP Requirements," Revision 0, dated June 16, 1997.
Retrieved from "https://kanterella.com/w/index.php?title=W3F1-2023-0018,_Updated_Final_Supplemental_Response_to_NRC_Generic_Letter_2004-02&oldid=3531989"