ML080670135

Supplemental Response to GL-04-002, Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized-Water Reactors

ML080670135
Person / Time
Site:	Indian Point
Issue date:	02/28/2008
From:	Joseph E Pollock Entergy Nuclear Operations
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
GL-04-002, NL-08-025
Download: ML080670135 (132)

Text

Indian Point Energy Center 450 Broadway, GSB P.O. Box 249 YJTD~EJ~fBuchanan, N.Y. 10511-0249 JI.E. Pollock Site Vice President Administration February 28, 2008 Re:

Indian Point Nuclear Generating Units No. 2 and 3 Docket Nos. 50-247 and 50-286 N L-08-025 Document Control Desk U.S. Nuclear Regulatory Commission Mail Stop O-Pl-17 Washington, DC 20555-0001

SUBJECT:

Supplemental Response to NRC Generic Letter 2004-02, "Potential Impact Of Debris Blockage On Emergency Recirculation During Design Basis Accidents At Pressurized-Water Reactors"

REFERENCES:

1.

NRC Generic Letter 2004-02, "Potential Impact of Debris Blockage on Emergency Recirculation during Design Basis Accidents at Pressurized-Water Reactors", dated September 13, 2004.

2.

NIL-05-023, "90-Day Response to NRC Generic Letter 2004-02, Potential Impact of Debris Blockage on Emergency Recirculation during Design Basis Accidents at Pressurized-Water Reactors", dated February 28, 2005.

3.

NIL-05-094, "Response to NRC Generic Letter 2004-02, Potential Impact of Debris Blockage on Emergency Recirculation during Design Basis Accidents at Pressurized-Water Reactors", dated September 1, 2005.

4.

NL-05-133, "Supplemental Response to NRC Generic Letter 2004-02, Potential Impact of Debris Blockage on Emergency Recirculation during Design Basis Accidents at Pressurized-Water Reactors", dated December 15, 2005.

5.

NL-07-074, "Request for Extension of Completion Date for Indian Point Unit 2 Corrective Actions and Modifications Required by Generic Letter 2004-02, Potential Impact of Debris Blockage on Emergency Recirculation during Design Basis Accidents at Pressurized-Water Reactors", dated September 17, 2007.

N L-08-025 Page 2 of 3

6.

NL-07-1 29, "Revised Request for Extension of Comp letion Date for Indian Point Unit 3 Corrective Actions and Modifications Required by Generic Letter 2004-02, Potential Impact of Debris Blockage onEmergency Recirculation during Design Basis Accidents at Pressurized-Water Reactors", dated December 3, 2007.

7.

NRC letter to Mr. M. Balduzzi, "Indian Point Nuclear Generating Unit No. 2 -

Approval of Extension Request for Corrective Actions Required by Generic Letter 2004-02", dated November 20, 2007.

8.

NRC letter to Mr. M. Balduzzi, "Indian Point Nuclear Generating Unit No. 3 -

Approval of Revised Extension Request for Corrective Actions Required by Generic Letter 2004-02", dated December 20, 2007.

9.

NRC letter to A. Pietrangelo (Nuclear Energy Institute), "Revised Content Guide for Generic Letter 2004-02 Supplemental Responses", dated November 21, 2007.

10.

NRC letter to Mr. M. Balduzzi, "Indian Point Nuclear Generating Unit Nos. 2 and 3 - Draft Open Items from Staff Audit of Corrective Actions to Address Generic Letter 2004-02", dated January 31, 2008.

Dear Sir or Madam:

The purpose of this submittal is to provide Entergy's supplemental response to Generic Letter (GL) 2004-02 (Reference 1). The Nuclear Regulatory Commission (NRC) issued GL 2004-02 to request that addressees perform an evaluation of the emergency core cooling system (ECCS) and containment spray system (CSS) recirculation functions in light of the information provided in the GL and, if appropriate, take additional actions to ensure system function. The request was based on identified potential susceptibility of the pressurized water reactor recirculation sump screens to debris blockage during design basis accidents requiring recirculation operation of ECCS or CSS and on the potential for additional adverse effects due to debris blockage for flow paths necessary for ECCS and CSS recirculation and, containment drainage.

Entergy responded to the GL in References 2, 3 and 4. By References 5 and 6, Entergy requested an extension to the December 31, 2007 due date for completion of the actions required by the GL.

The NRC, in References 7 and 8, approved the due date extensions to completion of the spring 2008 refueling outage (Unit 2) and June 30, 2008 (Unit 3). In accordance with the NRC's GL 2004-02 response content guide (Reference 9), Entergy will submit a final response for each unit within 90 days of the completion of all actions. These final responses will supplement, and revise as necessary, the information presented in this submittal. In addition, Entergy recognizes that the resolution of the NRC's GL 2004-02 audit open items (Reference 10) will impact the information contained in this submittal. Docketed open item responses will be provided within 60 days of the issuance of the final audit report.

Attachments 1 and 2 provide the Entergy supplemental response to GL 2004-02 for Indian Point Units 2 and 3. The response addresses the actions and methodologies used at Indian Point to resolve the issues identified in the GL.' This response was prepared using NRC guidance provided in Reference 9.

N L-08-025 Page 3 of 3 No new commitments are being made in this submittal. If you have any questions or require additional information, please contact Mr. R. Walpole, Licensing Manager at 914-ý374-67110.

Ideclare under' penalty of perjury that the foregoing is true and correct. Executed on 2- -9 16 Si nce rely, J. E. Pollock Site Vice President Indian Point Energy Center : Indian Point Units 2 and 3 Supplemental Response to NRC Generic Letter 2004-02 : Indian Point Units 2 and 3'Emergency Core Cooling System Single Line Drawings cc:

Mr. John P. Boska, Senior Project Manager, NRC NRR DORL Mr. Samuel J. Collins, Regional Administrator, NRC Region 1 NRC Resident Inspector, 1P2 NRC Resident Inspector, IP3 Mr. Paul Eddy, New York State Dept. of Public Service

ATTACHMENT 1 TO NL-08-025 INDIAN POINT UNIT 2 AND 3 SUPPLEMENTAL RESPONSE TO NRC GENERIC LETTER 2004-02 ENTERGY NUCLEAR OPERATIONS, INC INDIAN POINT NUCLEAR GENERATING UNITS 2 AND 3 DOCKETS 50-247 AND 50-286

NL-08-025 Page 1 of 125 Response to NRC Generic Letter 2004-02, Potential Impact Of Debris Blockage On Emergency Recirculation During Design Basis Accidents At Pressurized-Water Reactors Overall Compliance USNRC Issue 1:

Provide in formation requested in GL 2004-02, "Requested In formation." Item 2(a) regarding compliance with regulations. That is, provide confirmation that the EGGS and CSS 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 was updated to reflect the results of the analysis described above.

Entergy Response to Issue 1:

The recirculation functions of the Emergency Core Cooling System (ECCS) and Containment Spray System (CSS) under debris loading conditions will be in compliance with the regulatory requirements listed in the Applicable Regulatory Requirements section of the subject generic letter in accordance with the new regulatory guidance. In order to ensure compliance, Entergy has performed and continues to perform analyses to determine the susceptibility of the ECCS and CSS recirculation functions to adverse effects of post-accident debris blockage and operation with debris-laden fluids. The analyses to date conform to the greatest extent practicable to the NEI 04-07 Guidance Report methodology (GR) (Reference 1) as supplemented by the NRC Safety Evaluation Report (SER)(Reference 2).

Entergy responded to the GL (Reference 3) in References 4, 5 and 6. By References 7 and 8, Entergy requested an extension to the December 31, 2007 due date for completion of the actions required by the GL. The NRC, in References 9 and 10, approved the due date extensions to completion of the spring 2008 refueling outage (Unit 2) and June 30, 2008 (Unit 3). In accordance with the.NRC's GL 2004-02 response content guide (Reference 11), Entergy will submit a final response for each unit within 90 days of the completion of all actions. These final responses will supplement, and revise as necessary, the information presented in this submittal. In addition, Entergy recognizes that the resolution of the NRC's GL 2004-02 audit open items (Reference 12) will impact the information contained in this submittal. Docketed open item responses will be provided within 60 days of the issuance of the final audit report.

In its extension requests Entergy identified the actions to be completed and provided the re asons for the due date extensions. Upon completion of the open actions identified, Entergy will have completed all the required actions to confirm that the ECCS and CSS recirculation functions are in compliance with all applicable regulatory requirements listed in the GL.

In response to the issues identified in the GL, Entergy has installed two passive strainer assemblies in the internal recirculation and containment sumps of both Indian Point units. The modifications replaced the existing grating and fine screen in the internal recirculation (IR) and vapor containment (VC) sumps with flow barriers and basket (Top-Hat) type strainer assemblies designed to accommodate the predicted increased post-accident debris loads. The new strainers are sized to limit the head loss across them to ensure positive Net Positive Suction Head (NPSH) margin for the IR and residual heat removal (RHR) pumps. The flow channeling barriers are designed to route the post-LOCA water into the reactor sump and then up through the incore instrumentation tunnel to the VC annulus through openings in the crane wall before entering the IR

N L-08-025 Page 2 of 125 sump or the VC sump. This flow path is credited so that a large quantity of the LOCA generated debris will settle in the reactor sump or elsewhere in the VC before reaching the IR or VC sump.

Entergy plans to install an extension to the Unit 2 VC sump strainers during the spring 2008 refueling outage.

The passive strainer assemblies are sized for an acceptable head loss based on the bounding case debris load generated following a large break loss of coolant accident (LBLOCA) in order to ensure that high head safety injection (HHSI) pump, IR pump and RHR pump NPSH and system flow rate requirements are met. The design basis for the strainers includes providing sufficient flow area for the most limiting scenario to ensure that the design basis flow area is available to mitigate the consequences of a LOCA under post-LOCA design basis debris and chemical loading conditions.

Licensing basis changes will be required as a result of analyses or plant modifications made to ensure compliance with the regulatory requirements listed in the Applicable Regulatory Requirements section of the subject generic letter. The already approved and potential licensing basis changes are further discussed under Item 3.p "Licensing Basis".

The major areas of conservatism include the application of the Nuclear Energy Institute (NEI) 04-07 methodologies in determining the amount and transportation of LOCA generated debris, deterministically calculated minimum sump water inventory and applying the debris mixed that exceeds the Indian Point design basis requirements in the debris head loss testing.

General Description of and Schedule for Corrective Actions USNRC Issue 2:

Provide a general description of actions taken or planned, and dates for each. For actions planned beyond December 31, 2007, 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. Efforts to implement the identified actions should be initiated no later than the first refueling outage starting after April 1, 2006. All actions should be completed by December 31, 2007 Provide justification for not implementing the identified actions during the first refueling outage starting after April 1, 2006. If all corrective actions will not be completed by December 31, 2007, describe how the regulatory requirements discussed' in the Applicable Regulatory Requirements section will be met until the corrective actions are completed.

Enterpv Resp~onse to Issue 2:

The following corrective action activities in association with the resolution of GL 2004-02 have been completed:

Miscellaneous o Containment walkdowns to identify and quantify the types and locations of potential debris sources o Programmatic and procedural enhancements

N L-08-025 Page 3 of 125 Hardware Installation of replacement IR and VC sump passive strainers o

Installation of flow channeling barriers to enhance debris settlement o

Installation of a debris trash rack on the fuel transfer canal drain to preclude blockage and consequential water holdup Testing o

Dissolution/erosion measurements of plant specific calcium silicate (Unit 2).

Strainer head loss testing - debris only Chemical effects testing at Vuez Analysis o

Debris generation analyses o

Debris transport analyses (subject to revision) o Strainer head loss qualification - debris only (Unit 2 and Unit 3 (preliminary))

o Clean screen head loss evaluation o

Post-'ac'cident containment water level calculations (subject to revision) o Available net positive suction head (NPSHA) analysis (subject-to revision) o Component (excluding pumps) downstream effects evaluations o

Fuel blockage downstream effects evaluations Licensing o

Submittal of buffer replacement license amendment request (Unit 2)

In order to meet the regulatory requirements, Entergy has scheduled the following activities.

Hardware o

Installation of buffer replacement modification packages (Units 2'and 3). Unit 3 installation subject to prior NRC approval o

Installation of a VC sump strainer extension outside the crane wall and miscellaneou's other modifications (Unit 2)

Analysis o

Revision to NPSHA analyses (Units 2 and 3.)

o Revision to debris transport analyses (Units 2 and 3)

Strainer head loss qualification including debris and chemical effects (Units 2 and 3)ý Downstream effects evaluations of pumps and vessel (Units 2 and 3) o Resolution of NRC audit open items and supporting activities (Units 2 and 3)

Licensing o

Preparation and submittal of a buffer replacement license amendment request (Unit 3) o Preparation and submittal of a passive failure related license amendment request (Units 2 and 3)

N L-08-025 Page 4 of 125 Specific Information Regarding Methodology for Demonstrating Compliance USNHC Issue 3a:

Break Selection The objective of the break selection process is to identify the break size and location that present the greatest challenge to post-accident sump performance.

1. Describe and provide the basis for the break selection criteria used in the evaluation.

2. State whether secondary line breaks were considered in the evaluation (e.g.,

main steam and feedwater lines) and briefly explain why or why not.

3. Discuss the basis for reaching the conclusion that the break size(s) and locations chosen present the greatest challenge to post-accident sump performance.

Entergy Response to, Issue 3a.1:

Indian Point evaluated a number of break locations and piping systems, and considered breaks that rely on recirculation to mitigate the event. The following break location criteria were considered:

Break Criterion No. 1 - Breaks in the RCS with the largest potential for debris; Break Criterion No. 2 - Large breaks with two or more different types of debris; Break Criterion No. 3 - Breaks with the most direct path to the sump; Break Criterion No. 4 - Large breaks with the largest potential particulate debris to insulation ratio by weight; and Break Criterion No. 5 - Breaks that generate a "thin-bed" - high particulate with 1/8" fiber bed.

This spectrum of breaks is consistent with that recommended in the SER.

The evaluations considered breaks in the primary coolant system piping having the potential for reliance on ECCS sump recirculation. The review determined that a primary coolant system piping large break loss of coolant accident (LBLOCA) including alternate break LOCA (ABLOCA) and certain primary coolant system piping small break LOCAs (SBLOCAs) would require ECCS sump recirculation. Indian Point considered other high energy line breaks (e.g., secondary side breaks) and determined that sump operation was not required.

For alternate breaks, Section 6.2 of the SER recommends a break size consisting of a guillotine break equating to an effective break area of 196.6 in 2. At Indian Point, this corresponds to a 11.5 inch (103.9 in 2) pressurizer surge line break for debris generation.

For small breaks, only piping that is 2" in diameter and larger was considered. This is consistent with the Section 3.3.4.1 of the SER, which states that breaks less than 2 inches in diameter need not be considered.

LBLOCA, ABLOCA, and SBLOCA cases are calculated with the same conservative methodology described for Region I breaks in Section 6.3 of the SER. Hence, the LBLOCA evaluations for IPEC do not consider the reductions that would be permitted with the more realistic modeling of debris generation, transport, and accumulation if applying the alternate evaluation methodology.

NL-08-025 Page 5 of 125 Enteray Response to Issue 3a.2:

Secondary line breaks were not considered because they do not lead to ECCS recirculation mode.

Each steam generator has a fast closing stop valve and a check valve. These eight (8) valves prevent the blowdown of more than one (1) steam generator regardless of break location, thereby retaining three (3) steam generators for heat removal after the faulted steam generator has completed blowdown.

Enterav Response to Issue 3a.3:

The debris generation evaluations identified break locations that provided limiting conditions for each of the 5 break selection criteria above. The possible break cases were identified according to the limiting cases for both the North and South compartments for large, alternate and small breaks.

Section 3.3.5 of the SER describes a systematic licensee approach to the break selection process which includes beginning the evaluation at an initial location along a pipe and stepping along in equal increments (5 foot increments per the SER) considering breaks at each sequential location.

However, for Indian Point the use of spreadsheets allowed significantly smaller resolution such that the calculation considers all breaks along the length of the pipe thereby insuring the selected break locations produced the largest amounts of debris. Unit 2 used a maximum resolution of 2.1 feet with an average of 0.136 feet. Unit 3 used a maximum resolution of 2.0 feet with an average of

0. 195 feet.

Indian Point Unit 2 For SER break selection criterion No. 1, thirteen (13) possible break cases were identified at the following locations for generating the maximum quantities of fiber or particulate fines:

1. Case 1: LBLOCA at the Hot Leg near the #22 Steam Generator for generating the maximum mass of fiber fines in the South Side Compartment (chosen to evaluate Break Criterion Nos. 1, 2, and 3)

2. Case 2: LBLOCA at the Cross-Over Leg near the #22 RCP Nozzle for generating the maximum mass of particulate fines in the South Side Compartment (chosen to evaluate Break Criterion Nos. 1, 2, 3, and 4)

3. Case 3: LBLOCA at the Cross-Over Leg near the #24 Steam Generator for generating the maximum mass of fiber fines in the North Side Compartment (chosen to evaluate Break Criterion Nos. 1, 2, and 3)

4. Case 4: LBLOCA at the Cross-Over Leg near the #24 Steam Generator for generating the maximum mass of particulate fines in the North Side Compartment (chosen to evaluate Break Criterion Nos. 1, 2, 3, and 4)

5. Case 5: ABLOCA at the Cold Leg near the #21 Steam Generator for generating the maximum mass of fiber fines in the South Side Compartment (chosen to evaluate Break Criterion Nos. 1 and 3)

6. Case 6: ABLOCA at the RH R Loop #22 suction line (Line No. 10) for generating the maximum mass of particulate fines in the South Side Compartment (chosen to evaluate Break Criterion Nos. 1, 3, and 4)

NL-08-025 Page 6 of 125

7. Case 7: ABLOCA at the Cross-Over Leg at the bottom of the #24 Steam Generator for generating the maximum mass of fiber fines in the North Side Compartment (chosen to evaluate Break Criterion Nos. 1 and 3)

8. Case 8: ABLOCA at the Pressurizer Surge line for generating the maximum mass of particulate fines in the North Side Compartment (limiting break of Break Criterion Nos. 1, 3, and 4)

9. Case 9:. SB LOCA at the Cross-Over leg near the #21 Steam Generator for generating the maximum mass of fiber fines in the South Side Compartment (chosen to evaluate Break Criterion Nos. 1 and 3)

10. Case 10: SBLOCA at the RHR Loop #22 suction line for generating the maximum mass of particulate fines in the South Side Compartment (Line No. 10) (chosen to evaluate Break Criterion Nos. 1, 3, and 4) 11. Case 11: SBLOCA at the Hot Leg at the bottom of the #23 Steam Generator for generating the maximum mass of fiber fines in the North Side Compartment (chosen to evaluate Break Criterion Nos. 1 and 3)

12. Case 12: SBLOCA at the Pressurizer Surge line for generating the maximum mass of particulate fines in the North Side Compartment (chosen to evaluate Break Criterion Nos. 1, 3, and 4)

13. Case 13: Reactor Vessel nozzle break in the Reactor Cavity These cases involved four large break cases, four alternate break cases, four small break cases, and the nozzle break within the Reactor Cavity. The results of the evaluation of insulation debris generation for Break Criterion No. 1 determined that all 13 breaks are limiting based on either the type or amount of debris generated.

It was determined that the debris generated by the 4 large break limiting cases for Break Criterion No. 1 bounded the debris generated for Break Criterion No.. 2 "large breaks with two or more different types of debris." Three of the four large break limiting cases contained a mixture of Asbestos, Temp-Mat, Nukon, Transco Blanket, and reflective metal insulation (RMI) with the fourth case containing additional fiberglass insulation. The evaluation concluded that these 4 break cases generate the largest amount of debris as well as the most limiting combinations of debris.

For Break Criterion No. 3, "breaks with the most direct path to the sump," the most limiting case is a break at the Hot Leg near the #22 Steam Generator as listed for Break Criterion No. 1. Any pipeline closer to the sump is not large enough to produce a HELB capable of producing large amounts of debris. The transport calculation, determines a conservative set of transport fractions applicable to all breaks within the crane wall.

For Break Criterion No. 4, "large breaks with the largest potential particulate debris to insulation ratio by weight," the largest quantities of transportable particulate insulation are found on Line No.

10, the Pressurizer, and the Pressurizer Surge Line. The large break cases in this area were evaluated to determine that Case 2 at the Cross-Over Leg near the #22 RCP nozzle has the maximum particulate load. Consequently, this maximum particulate load is evaluated for all possible fiber loads from no fiber, through thin bed thickness, and onto the maximum possible fiber load.

NL-08-025 Page 7 of 125 For Break Criterion No. 5, "breaks that generate a thin-bed," many possible HELBs can be postulated that would generate and transport the small quantity of fibrous debris needed to form a thin-bed. According to testing performed on Top-Hat strainer modules with similar geometry, the thin-bed effect was shown not to occur for the Indian Point Top-Hat strainer modules.

In summary, it was determined that a postulated LBLOCA at the Hot Leg near the #22 Steam Generator, the Cross-Over Leg near the #22 RCP Nozzle, or the Cross-Over Leg near the #24 Steam Generator would bound the large break cases covered in Break Criterions No. 1 and 2. A postulated ABLOCA at the Cold Leg near the #21 Steam Generator, the RHR Loop #22 suction line (Line No. 10), the Cross-Over Leg at the bottom of the #24 Steam Generator, or the Pressurizer Surge line would bound the alternate break cases covered in Break Criterion No. 1. A postulated SBLOCA at the Cross-Over leg near the #21 Steam Generator, the Hot Leg near the bottom of the #23 Steam Generator, the RHR Loop #22 suction line (Line No. 10), or the Pressurizer Surge Line would bound the small break cases covered in Break Criterion No. 1. Break Criterion No. 3 is met by the conservative transport fractions applied to all cases. Case 2 at the Cross-Over Leg near the #22 RCP nozzle would bound Break Criterion No. 4. Finally, testing has shown that the thin bed effect, as covered by Break Criterion No. 5, does not occur on the Top-Hat strainer modules used at Unit 2.

Indian Point Unit 3 For SER break selection criterion No. 1, thirteen (113) possible break cases were identified at the following locations for generating the maximum quantities of fiber or particulate fines:

1. Case 1: LBLOCA at the Cross-Over Leg at the bottom of the #32 Steam Generator for generating the maximum mass of fiber fines in the South Side Compartment (chosen to evaluate Break Criterion Nos. 1, 2, and 3)

2. Case 2: LBLOCA at the Cold Leg between the #31 Reactor Coolant Pump and the penetration to the Reactor for generating the maximum mass of particulate fines in the South Side Compartment (chosen to evaluate Break Criterion Nos. 1, 2, and 3)

3. Case 3: LBLOCA at the Cross-Over Leg at the bottom of the #34 Steam Generator for generating the maximum mass of fiber fines in the North Side Compartment (chosen to evaluate Break Criterion Nos. 1, 2, and 3)

4. Case 4: LBLOCA at the Cold Leg between the #33 Reactor Coolant Pump and the penetration to the Reactor for generating the maximum mass of particulate fines in the North Side Compartment (chosen to evaluate Break Criterion Nos. 1, 2, and 3)

5. Case 5: ABLOCA at the Cold Leg at the bottom of the #32 Reactor Coolant Pump for generating the maximum mass of fiber fines in the South Side Compartment (chosen to evaluate Break Criterion Nos. 1 and 3)

6. Case 6: ABLOCA at the Cold Leg between the #31 Reactor Coolant Pump and the penetration to the Reactor for generating the maximum mass of particulate fines in the South Side Compartment (chosen to evaluate Break Criterion Nos. 1 and 3)

N L-08-025 Page 8 of 125

7. Case 7: ABLOCA at the Cold Leg at the #34 Reactor Coolant Pump for generating the maximum mass of fiber fines in the North Side Compartment (chosen to evaluate Break Criterion, Nos. 1 and 3)

8. Case 8: ABLOCA at the Cold Leg between the #33 Reactor Coolant Pump and the penetration to the Reactor for generating the maximum mass of particulate fines in the North Side Compartment (chosen to evaluate Break Criterion Nos. 1, and 3)

9. Case 9: SBLOCA at the Cold Leg at the bottom of the #32 Reactor Coolant Pump for generating the maximum mass of fiber fines in the South Side Compartment (chosen to evaluate Break Criterion Nos. 1 and 3)

10. Case 10: SBLOCA at the Cold Leg Return at the bottom of the #32 Reactor Coolant Pump for generating the maximum mass of particulate fines in the South Side Compartment (Line No. 10) (chosen to evaluate Break Criterion Nos. 1, 3, and 4) 11. Case 11: SBLOCA at the Cold Leg at the bottom of the #34 Reactor Coolant Pump for generating the maximum mass of fiber fines in the North Side Compartment (chosen to evaluate Break Criterion Nos. 1 and 3)

12. Case 12: SBLOCA at Line No. 61 for generating the maximum mass of particulate fines in the North Side Compartment (chosen to evaluate Break Criterion Nos. 1, 3, and 4)

13. Case 13: Reactor Vessel nozzle break in the Reactor Cavity These cases involved four large break cases, four alternate break cases, four small break cases and the nozzle break within the Reactor Cavity. The results of the evaluation of insulation debris generation for Break Criterion No. 1 determined that all 13 breaks are limiting based on either the type or amount of debris generated.

It was determined that th e debris generated by the 4 large break limiting cases for Break Criterion No. 1 bounded the debris generated for Break Criterion No. 2 "large breaks with two or more different types of debris." All of the large break limiting cases contained Calcium Silicate, Temp-Mat, Nukon, and fiberglass with 3 of the 4 containing Asbestos and 3 of the 4 containing mineral wool. The evaluation concluded that these 4 break cases generate the largest amount of debris, and also the most limiting combinations of debris.

For Break Criterion No. 3, "breaks with the most direct path to the sump," the most limiting case is a break at the Cross-Over Leg at the bottom of the #32 Steam Generator as listed for Break Criterion No. 1. Any pipeline closer to the sump is not large enough to produce a HELB capable of producing large amounts of debris. The debris transport evaluations determine a conservative set of transport fractions applicable to all breaks within the crane wall.

For Break Criterion No. 4, "large breaks with the largest potential particulate debris to insulation ratio by weight," the largest quantities of transportable particulate insulation are found on the Cold Legs and the Pressurize 'r. The large break cases in this area were evaluated to determine that Case 4 at the Cold Leg between the #33 Reactor Coolant Pump and the penetration to the Reactor has the maximum particulate load. Consequently, this maximum particulate load is evaluated for all possible fiber loads from no fiber, through thin bed thickness, and onto the maximum possible fiber load.

N L-08-025 Page 9 of 125 For Break Criterion No. 5, 'breaks that generate a thin-bed," many possible HELBs can be postulated that would generate and transport the small quantity of fibrous debris needed to form a thin-bed. According to testing performed on Top-Hat strainer modules with similar geometry, the thin-bed effect was shown not to occur for the Indian Point Top-Hat strainer modules as documented in the head loss test report.

In summary, it was determined that a postulated LBLOCA at the Cross-Over Leg at the' bottom of the #32 Steam Generator, the Cold Leg between the #31 Reactor Coolant Pump and the penetration to the Reactor, the Cross-Over Leg at the bottom of the #34 Steam Generator, or the Cold Leg between the #33 Reactor Coolant Pump and the penetration to the Reactor would bound the large break cases covered in Break Criterions No. 1 and 2. A postulated ABLOCA at the Cold Leg at the bottom of the #32 Reactor Coolant Pump, the Cold Leg between the #31 Reactor Coolant Pump and the penetration to the Reactor, the Cold Leg at the #34 Reactor Coolant Pump, or the Cold Leg between the #33 Reactor Coolant Pump and the penetration to the Reactor would bound the alternate break cases covered in Break Criterion No. 1. A postulated SBLOCA at the Cold Leg at the bottom of the #32 Reactor Coolant Pump, the Cold Leg Return at the bottom of the

1. 32 Reactor Coolant Pump, the Cold Leg at the bottom of the #34 Reactor Coolant Pump, or Line No. 61 would bound the small break cases covered in Break Criterion No. 1. Break Criterion No. 3 is met by the conservative transport fractions applied to all cases. Case 4 at the Cold Leg between the #33 Reactor Coolant Pump and the penetration to the Reactor would bound Break Criterion No. 4. Finally, testing has shown that the thin bed effect, as covered by Break Criterion No. 5, does not occur on the Top-Hat strainer modules used at Unit 3.

USNRC Issue 3b:

Debris Generation/Zone of Influence (Z01) (excluding coatings)

The objective of the debris genera tion/ZOI process is to determine, for each postulated break location: (1) the zone within which the breakjet forces would be sufficient to damage materials and create debris; and (2) the amount of debris generated by the breakjet forces.

1. Describe the methodology used to determine the ZO1s for generating debris. Identify which debris analyses used approved methodology default values. For debris with ZO1s not defined in the guidance report (GR)/safety evaluation (SE), or if using other than default values, discuss method(s) used to determine Z01 and the basis for each.

2. Provide destruction ZO1s and the basis for the ZO1s for each applicable debris constituent.

3. Identify if destruction testing was conducted to determine ZO1s. If such testing has not been previously submitted to the UISNRC for review or information, describe the test procedure~and results with reference to the test report(s).

4. Provide the quantity of each debris type generated for each break location evaluated. If more than four break locations were evaluated, provide data only for the four most limiting locations.

5. Provide total surface area of all signs, placards, tags, tape, and similar miscellaneous materials in containment.

Enterpy Response to Issue 3b.1:

Indian Point applied the ZOI refinement discussed in Section 4.2.2.1.1 of the SER, which allows the use of debris-specif ic spherical ZOls. Using this approach, the amount of debris generated within each ZOI is calculated and the individual contributions from each debris type are summed to arrive at a total debris source term.

N L-08-025 Page 10 of 125 The destruction pressures and ZOls for the RMI, Nukon and Temp-Mat were obtained from a list of common PWR materials of potential debris contributors in Table 3-2 of the SER. The destruction pressures and ZOls for Transco blankets, fiberglass, and mineral wool insulation are assumed to be the same as Nukon due to their similar material properties. This assumption is supported by discussions in both the SER and the NEI-04-07 GR.

No recommended destruction pressures or ZOls are provided in the SER or the NEI-04-07 GR, Reference 2, for asbestos insulation. The asbestos insulation at Indian Point was examined using a scanning electron microscope, and the result indicates that the asbestos insulation is calcium silicate with asbestos fiber. A proprietary Alion Size Distribution Report conservatively uses an increased ZOl of 6.4D (compared to a SER suggested value of 5.5D) for calcium silicate insulation.

Therefore, it is assumed that the asbestos and calcium silicate insulation with jacketing installed at, Indian Point has the same destruction properties as calcium silicate listed in the Alion Report. The asbestos insulation without jacketing (asbestos with cloth) also is not listed in the SER or GR. Due to the minimal amount and dispersed location of asbestos within the crane wall, the ZOl was increased from the value for jacketed asbestos insulation to the largest ZOl of the considered materials, 28.6, with a destruction pressure of 2.4 psig.

Neither the GR nor the SER provides a destruction pressure or ZOI for Fiber (Marinite or Transite)

Board. The Transite remaining in containment is a cementatojus product containing asbestos (41.2 to 45.5% asbestos and 54.5 to 58.8% Portland Type 1 cement) and is no longer available. A request for material substitution approved the use of Marinite I for replacement of Transite when required. Marinite I is composed of 65-75% Calcium Silicate, 20 - 25% Calcium Metasilicate, 4 -

8% natural Organic Fiber and 0.1 - 2% Crystalline Silica. Both materials are solid, self-supporting structural insulation materials. The GR Table 4-1 notes that Marinite board has a flexure strength (Modulus of Rupture) approximately 14 times that of typical calcium silicate insulation. Present day non-asbestos Transite has a flexure strength even greater than that of Marinite. Based on these properties and the recommendation by the GR that Marinite could conservatively be assumed to have the destruction pressure of calcium silicate insulation, it is assumed that both Transite and Marinite will have the same destruction pressure and ZO! as calcium silicate (ZOI = 6.4D).

Enteray Response to Issue 3b.2:

The zone of influence (ZOI) is defined as a spherical volume about the break in which the jet, pressure is larger than the destruction/damage pressure of insulation, coatings, and other materials impacted by the break jet. The use of spherical geometry constitutes a significant conservatism as the break flow would be directed to only some fraction of the sphere.

N L-08-025 Page 11 of 125 The ZOls of each type of debris (excluding coatings) for provided below:

Table 3b.2-1 Unit 2 Zones of Influence Debris Type ZOI RadiusRernc Debris Type(Radius/Break Diameter)Rernc DPSC "Mirror" with

2.

E Standard Bands (RMI)

2.

E Nukon 17 SER Tranco Banke 17Assumed equal to Tranco Banke 17Nukon Fibeglas 17Assumed equal to Fibeglas 17Nukon Temp-Mat 11.7 SER Asbetos ith loth28.6Conservative Asbetos ith loth28.6Assumption Asbetos ith acke 6.4Alion Size Distribution Asbetos ith acke 6.4Report Table 3b.2-2 Unit 3 Zones of Influence ZOl Radius Debris Type (Radius/Break Reference Diameter)

DPSC "Mirror" with 28.6 SER Standard Bands (RMI)

Nukon 17 SER Fiberglass

.17 Assumed equal to Nukon Temp-Mat 11.7 SER Mineral Wool with 17 Assumed equal to Nukon Jacket Alion Size Distribution Asbestos with Jacket 6.4 Rpr Calcium Silicate with 286Conservative

• Cloth 286Assumption

.Calcium Silicate with 64Alion Size Distribution

• Jacket 64Report Fiber (Marinite) Board /6.4

• Conservative Transite Assump tion Enteray Response to Issue 3b.3:

Indian Point applied the ZOl refinement discussed in Section 4.2.2.1.1 of the SER which allows the use of debris-specific spherical ZOls. No new destruction testing was used to determine the ZOls listed above. All destruction properties are based on published values.

Enterpy Response to Issue 3b.4:

Using the ZOls listed in this section and the size distributions provided in Section 3c, quantities of generated debris for each break case were calculated for each type of insulation. The quantities of

N L-08-025 Page 12 of 125 debris generated for the four most limiting break cases are listed below:

Indian Point Unit 2 Table 3b.4-1 n~ee M fih,=r finac in tho cr-."th ciria rmn nrtmant~

I mit 9 ('nea 1 m RI n'(CA (mnnvim "

Insuatin Tye TtalAmout Fnes Smal Pices Larg Pices Intact Insuatin Tye TtalAmout Fnes Smal Pices Larg Pices Blankets Destroyed Asbestos (Jacketed 283.41 Lbm 74.79 54.96 153.66 andCloth)

Temp-Mat 936.78 Lbm 72.61 281.62 282.44 300.10 Nukon 2449.83 Lbm 365.65 1393.21 334.23 356.74 Transco Blanket 103.71 Lbm 16.24 61.01 12.79 13.67 Fiberglass 2.54 Lbm 0.20 0.18 1.04 1.12 RMI 7,762.12 ft 2 5,821.59 1,940.53 Table 3b.4-2 Unit 2 Case 2: LBLOCA (maximum mass of particulate fines in the south side compartment)

IsltoTye Total Amount Fns SalPes LrgPics Intact InultonTye Destroyed FieIml ics LrePee Blankets Asbestos (Jacketed 760.41 Lbm 180.41 121.20 458.80 and Cloth)______________

Temp-Mat 986.93 Lbm 93.10 364.38 256.71 272.75 Nukon 2035.09 Lbm 251.38 759.75 494.30 529.66, Transco Blanket 80.50 Lbm 11.42 39.12 14.47 15.49 RMI 7,762.12 ft 2 5,821.59 1,940.53-

NL-08-025 Page 13 of 125 Table 3b.4-3 LBLOCA (maximum mass of fiber fines in the north side compartment)

Unit 2 Case 3:

Insulation Type Total Amount Fines Small Pieces Large Pieces I Intact Destroyed I_________

Blankets Asbestos.(Jacketed 340.75 Lbm 83.91 58.29 198.54 and Cloth)_____________________

Temp -Mat 754.71 Lbm 52.94 204.23 241.23 256.31 Nukon 2405.34 Lbm 354.25 1342.71 342.63 365.75 Transco Blanket 132.46 Lbm 20.64 79.70 15.54 16.58 RMI 7,762.12 ft 2 5,821.59 1,940.53 Table 3b.4-4 Unit 2 Case 4: LBLO CA (maximum mass of particulate fines in the north side compartment)

IsltoTye Total Amount Fie mlIics LrePee Intact InultonTye Destroyed FieIml ics LrePee Blankets-Asbestos (Jacketed 342.98 Lbm 84.23 58.38 200.37 and Cloth)__

Temp-Mat 754.71 Lbm 52.94 204.23 241.23 256.31 Nukon 2397.49 Lbm 351.61 1327.72 347.34 370.82 Transco Blanket 132.46 Lbm 20.55 79.34 15.76 16.81 RMI 7,762.12 ft 2 5,821.59 1,940.53-

"I

NL-08-025 Page 14 of 125 Indian Point Unit 3 Table 3b.4-5

____________Unit 3 Case 1: LBLOCA (maximiumn mass of fiber fines)

Insulation Type Total Amount Fines Small Pieces Large Pieces IBlnetsc Destroyed I__-Blankets Asbestos 144.59 Lbm 33.26 21.69 89.65 Calcium Silicate 8.39 Lbm 1.93 1.26 5.20 Temp-Mat 1862.29 Lbm 247.83 981.75 306.77 325.94 Mineral Wool 33.09 Lbm 4.30 17.87 5.29 5.63 Nukon 1881.94 Lbm 268.77 989.80 301.38 322.00 Fiberglass 124.19 Lbm 19.79 73.95 14.71 15.73 RMI Fiber Board (Marnnite)/Transite

• Note that Fiber Board is used as a cable tray barrier.

Table 3b.4-6 Unit 3 Case 2: LBLOCA (maximum mass of particulate fines)

Insulation Type TostalAount Fines Small Pieces Large Pieces BlInktac Asbestos 468.34 Lbm 215.72 210.26 42.36 Calcium Silicate 8.39 Lbm 1.93 1.26 5.20 Temp-Mat 1310.22 Lbm 95.72 370.10 409.41 435.00 Mineral Wool Nukon 1752.94 Lbm 204.63 597.19 459.18 491.93 Fiberglass 74.13 Lbm 10.08 35.84 13.63 14.57 RMI Fiber Board*

(Marinite)ITransite

• Note that Fiber Board is used as a cable tray barrier.

NL-08-025 Page 15 of 125 Table 3b.4-7 Unit 3 Case 3: LBLOCA (maximium mass of fiber fines)______

insulation Type Total Amount Fines Small Pieces

'Large Pieces Blnktsc Destroyed Blankets Asbestos Calcium Silicate 311.89 Lbm, 71.73 46.78 193.37 Temp-Mat 3058.71 Lbm 331.44 1304.19 689.98 733.10 Mineral Wool 75.39 Lbm 11.27 46.17 8.70 9.25 Nukon 1996.74 Lbm 288.44 1061.64 312.61 334.05 Fiberglass 101.82 Lbm 14.79 58.17 13.98 14.89 RMI Fiber Board*

(Marinite)[Transite

• Note that Fiber Board is used as a cable tray barrier.

Table 3b.4-8 Unit 3 Case 4: LBLOCA (maximum mass of particltfie Insulation Type ToDetalAount Fines Pieces Large Pieces Intact Blankets Asbestos 342.78 Lbm 171.39 171.39 Calcium Silicate 274.39 Lbm 63.11 41.16 170.12 Temp-Mat 1393.29 Lb, 102.23 395.34 434.29 461.43 Mineral Wool 18.39 Lbm 1.47 1.29 7.54 8.09 Nukon 1801.69 Lbm 207.59 606.35 476.91 510.84 Fiberglass 41.83 Lb, 6.25 24.15 5.53.

5.90 RMI Fiber Board *

(Mari nite)IT rans ite

• Note that Fiber Board is used as a cable tray barrier.

NL-08-025 Page 16 of 125 The maximum quantity of debris results from a combination of break cases as shown in the debris generation evaluations. The use of these quantities represents a significant conservatism because no single ZOI exists that would generate this quantity.

Table 3b.4-9 Unit 2 Maximum Insulation Debris Quantity for LBLOCA Insulation Total Amount

%Fns

% Small

% Large I% intact BekLcto Type Destroyed

%ie Pieces Pieces jBlankets

~ ra~cto Asbestos 760.41 Lbm 23.7 %

15.9 %

60.3 %

Case 2 Temp-Mat 986.93 Lbm 9.4 %

36.9 %

26.0 %

27.6 %

Ca.se 2 Nukon 2449.83 Lbm 14.9 %

56.9 %

13.6 %

14.6 %

Cs Branketo 132.46 Lbm, 15.6 %

60.2 %

11.7 %

12.5 %

Case 3 Fiberglass 2.54 Lbm 7.9 %

7.1 %

40.9 %

44.1 %

Casel RMI 7,762.12 ft 2 75 %

25 %

Case 1-4

• Case 4 destroys the same total amount; however, more fines & small pieces are destroyed in Case 3.

Table 3b.4-1O0 Unit 3 Maximum Insulation Debris Quantity for LBLOCA Insulation Total

% Small

% Large

% Intact Type Amount

%-Fines Pieces Pieces Blankets Break Location Destroyed_____

Asbestos 468.34 46.1 %

44.9 %

9.0 %

Case 2 Lbm______

Calcium 311.'89 2.%

10%60%Case 3

Silicate Lbm

2.

50%6.

• Temp-Mat 3058.'71 10.8 %

42.6 %

22.6 %

24.0 %

Case 3 Lbm__

Mineral Wool 7*39 15.0%

61.2%

11.5 %

12.3%

Case 3 Lbm Nukon 1996.74, 14.5%

53.2%

15.7%

16.7%

Case 3 Lbm Fiberglass 124.19 15.9%

59.6%

11'.8%

12.7%

Casel1 Lbm Entergy Response to Issue 3b.5:

The containment walkdown reports document 242. (Unit 2) and 45.8 (Unit 3) square feet of tags and labels that could potentially transport to the sumps and obstruct strainer surface area. Refer to Section 3.d for details.

NL-08-025 Page 17 of 125 USNRC Issue 3c:

Debris Characteristics The objective of the debris characteristics determination process is to establish a conservative debris characteristics profile for use in determining the transportability of debris and its contribution to head loss. Provide the assumed size distribution for each type of debris.

1. Provide the assumed size distribution for each type of debris.

2. Provide bulk densities (i.e., including voids between the fibers/particles) and material densities (i.e., the density of the microscopic fibers/particles themselves) for fibrous and particulate debris.

3. Provide assumed specific surface areas for fibrous and particulate debris.

4. Provide the technical basis for any debris characterization assumptions that deviate from USNRC-approved guidance.

Enterpy Resp~onse to Issue 3c0:

The size distributions for the various types of insulation found within containment are listed below.

The RMI insulation size distribution was obtained from the values published in the GR and.SER.

Nukon, Temp-Mat, and Calcium Silicate insulation size distributions were obtained from the proprietary Alion Size Distribution Report. Transco blanket and fiberglass insulation are assumed to have the same destruction properties as Nukon due to their similar material properties (low density fiberglass).

Asbestos insulation is assumed to have the same destruction properties, including size distribution, as Calcium Silicate (see Section 3.b). Asbestos was found to be identical to Calcium Silicate using a scanning electron microscope. Since the ZOl for Asbestos was enlarged to 28.6 LID, it was assumed that the size distribution for the 2.7D to 6.4D zone of destruction for Calcium Silicate is applicable out to the enlarged ZOI.

Table 3c. 1-1 Size Distribution for Diamond Power Mirror (RMI)

Size

Ž:2.4 psi ZOl

____(28.6 LID)

Fines Small Pieces 75%

Large Pieces 25%

Intact (covered) Blankets For Nukon T M, Thermal-WrapTM, and Mineral Wool LDFG, it was determined that the debris size distribution within the ZOI can be best defined using three sub-zones. The size distributions within each of these sub-zones are shown in the Table below.

NL-08-025 Page 18 of 125 Table 3c. 1-2 Size Distribution for Nukon TM, Mineral Wool, and Fiberglass [Mineral Wool and Fiberglass assumed the same as Nukon]

Sie>18.6 psi ZOl 10.0 - 18.6 psi ZOl 6.0 - 10.0 psi ZOI Sie(7.0 UID)

(11.9 -7.0 L/D)

(17.0 -11.9L/ID)

Fines 20%

13%

8%

Small Pieces 80%

54%

7%

Large Pieces

-16%

41%

Intact (covered) Biankets

-17%

44%

Table 3c. 1-3 Size Distribution for Thermal-Wrap TM (Transco Blanket)

Sie>18.6 psi ZOI 10.0 - 18.6 psi ZOI 6.0 - 10.0 psi ZOI Sie(7.0 L/D)

(11.9 -7.0 LID)

(17.0 -11.9 L/D)

Fines 20%

13%

8%

Small Pieces 80%

54%

7%

Large Pieces

-16%

41%

Intact (covered) Blankets

-17%

44%

For Temnp-MatTM fiberglass, it was determined that the debris size distribution within the ZOI can best be defined using two sub-zones. The size distributions within each of these sub-zones are shown in the Table below.

Table 3c. 1-4 Size Distribution for Temp-Mat TM1 Sie>45.0 psi ZOI 10.2 - 45.0 psi ZOl Size(3.7 LID)

(11.7 - 3.7 LID)

Fines 20%

7%

Small Pieces 80%

27%

Large Pieces 32%

Intact (covered) Blankets

-34%

Table 3c. 1-5 Size Distribution for Cal-Sil [Asbestos assumed to be the same as Calcium Silicate]

Jacket Cloth Size

Ž!70 psi ZOl 20-70 psi ZOI

Ž70 psi ZOl

Žý2.4 psi ZOI (2.7 LID)

(6.4-2.7 LID)

(2.7 LID)

(28.6 L/D)

Fines 50%

23%

50%

23%

Small Pieces 50 %

15 %

50%*

15 %

Large Pieces62%62*

Intact (covered) Blankets

• Calcium -Silicate Chunk

NL-08-025 Page 19 of 125 Entergy Response to Issue 3c.2:

The material and bulk densities for the various types of debris are provided below.

Table 3c.2-1 Debris Types and Properties Density Used in Material Density Bulk Density Calculation Debris Type (Ibm/t3)

(lbm/ft3)

(Ibm/ft3)

NukonTM 159.0 2.4 2.4 Temp-Mat 162.0 11.8 11.8 Mineral Wool' 90.0 4, 6, 8,10 10 76 Fiberglass 159.0 2.4 2.4 75 Fiber Board (Marinite) 1 40-51 46 U)_

C:

Fiber Board (Transite) 190-1 00 100 Transco Blanket 159.0 2.4 2.4 Cal-Sil (Asbestos) 153.0 14.5 14.5 LatntFier94.0 2.4 (assumed) 94.0

_____Dirt/Dust 169.0

-169.0 Er~oxv 6129 (Floor) 64.9 64.9 (n

0 0-Epoxy 5000 (Floor) 88.0

-88.0 Epoxy 4129 (Wall/Concrete) 70.8 70.8 Epoxy 4000 (Wall/Concrete) 114.5 114.5

-Epoxy D-1 (Wall/Concrete) 92.2 92.2 Carbo Zinc 11 (Steel) 255.2 255.2 Carboline 890 (Steel) 108.0 108.0 195 Surfacer (Floor) 104.2 104.2 195 Surfacer (Wall/Concrete) 104.2 104.2 Phenoline 305 (Floor) 86.1

-86.1 Phenoline 305 (Wall/Concrete) 86.1

-86.1 Epoxy 6548/7107 (Inside ZOI) 101.7 101.7 Epoxy E-1 -7475 (Inside ZOI) 76.1

-76.1 High Temp. Aluminum (Inside ZOI) 90.0

-90.0 Epoxy/Epoxy Phenolic (Inside ZOI) 94.0 94.0 Alkyd Enamel (inside ZOI) 98.0

-98.0-High Temp. Aluminum (Outside ZOI) 90.0

-90.0 Epoxy/Epoxy Phenolic (Outside ZOI) 94.0

-94.0 White RTV / Black Poly Caulk 81.1 81.1 Inorganic Zinc 457

-457 Alkyd Enamel (Outside ZOI) 98.0 98.0

1. Note that Fiber Board is used as a cable tray barrier.

2. Asbestos is assumed to have the same properties as Cal-Sil (see Section 3.b).

N L-08-025 Page 20 of 125 Entergy Response to Issue 3c.3:

The particle diameter of latent particulate (dirt/dust) was assumed to be 17.3 pm based on the specific surface area of 106,000 ft-1 for use in the NUREG/CR-6224 (Reference 13) correlation as specified in the SER. Since the head loss across the installed sump screen is determined via testing for fiber, the specific fiber surface area was not used in the design basis for Indian Point, therefore, this value is not provided.

Enterpy Response to Issue 3c.4:

A complete discussion of the technical basis for the deviation from NRC guidance on the size distributions of Nukon TM, Temp-Mat TM, and Calcium Silicate insulation is located in the proprietary Alion Size Distribution Report. For fibrous debris, the Alion Report uses that same air-jet impact tests (AJIT) as the SER. However, conservatism with respect to the size distributions is removed based on the data collected for the fraction of small fines at various jet pressures. However, to remain conservative, a 10% penalty was added to the small debris fraction calculated from this data. The fraction of fines versus small pieces is based on the Drywell Debris Transport Study (DDTS - Reference 14). For Calcium Silicate insulation, the Alion Report uses the same Ontario Power Generation (OPG) testing as the SER and subdivides the ZOI to provide two size distributions.

The Alion Size Distribution Report outlines the methodology used to justify 4 distinct size categories of fiber glass. The 4 categories of size classification within each size distribution are consistent with the suggested refinements of the SER. The GR Section 3.4.3 recommends using a two category size distribution for insulation debris including: (1) small pieces (assumed to be the basic constituent of the material), and (2) large pieces (pieces greater than 4 inches). Although this size distribution is adequate for the baseline analysis, it allows for only limited benefit when computational fluid dynamics (CFD) analyses are used to refine the recirculation pool debris transport fractions. The NRC recognized this limitation in the SER. The SER Section 4.2.4 recommends a four category size distribution including: (1) fines that remain suspended (fines), (2) small piece debris that is transported along the pool floor (small pieces), (3) large piece debris with the insulation exposed to potential erosion (large pieces), and (4) large debris with the insulation still protected by a covering, thereby preventing further erosion (intact (covered) blankets). This is the~basis for the four size categories used by Alion to classify the size distributions of each type of fibrous insulation.

USNRC Issue 3d:-

Latent Debris The objective of the latent debris evaluation process is to provide a reasonable approximation of the amount and types of latent debris existing within the containment and its potential impact on sump screen head loss.

1. Provide the methodology used to estimate quantity and composition of latent debris.

2. Provide the basis for assumptions used in the evaluation.

3. Provide results of the latent debris evaluation, including amount of latent debris types and physical data for latent debris as requested for other debris under c.

above.

4. Provide amount of sacrificial strainer surface area allotted to miscellaneous latent debris.

N L-08-025 Page 21 of 125 Entergy Response to Issue 3d.1:

The evaluation for Latent Debris at Indian Point was performed in a manner consistent with the SER approved methodology and NEI walkdown guidance (Reference 15). The total source term was determined through the collection of debris samples from multiple locations throughout the containment. Conservatism was added by sampling those areas that exhibited unusual concentrations of dirt and dust. In addition to dirt and dust, foreign materials and other debris sources were surveyed and documented including tape, equipment labels, and fiberboard (cable tray fire protection).

Vertical, horizontal and equipment surfaces were sampled for dirt and dust. Sample areas were chosen by cognizant engineering personnel with the intent to produce bounding results. The containment was divided into categories from which a minimum of three samples were taken. Prior to collecting samples, the containment was surveyed through a series of walkdowns to locate desirable sample locations. Afterwards, maps and spreadsheets were constructed to assist in the collection effort. When possible, photographs of the sample site were taken before and after collection. Approximately 35 to 45 samples were taken throughout containment for each unit. From these samples, a calculation was performed to provide an estimate of the total amount of latent debris in containment. It was also noted that sample collection was conducted during a refueling outage and it appeared that no clean up efforts had yet been instigated.

Ente rgy Response to Issue 3d.2:

The characterization of latent debris followed the guidance in section 3.5.2.3 of the SER. 15% of the mass of dirt/dust/lint was categorized as latent fiber, the characteristic size was assumed to be equal to Nukon, 2.3E-5 ft (7.0 pm). Per the SER a mean fiber density of 1.5 g/cm3 (94 lbm/ft 3) was assumed, and the dirt/dust characteristic size was assumed to be 5.68E-5 ft (17.3 pm) with a density of 169 Ibm/ft 3.

Enteray Response to Issue 3d.3:

Results of the latent debris evaluations are provided in the following tables.

Table 3d.3-1 Unit 2 Final Latent Debris Values Latent Debris Type Inside Crane Wall Outside Crane Above Operating Wall Deck Tape and Equipment Metal Non-Metal 2

12ft Labels 2.86 ft 2 20.66 ft 2 211.13 ftf.2f TieWrpsSouth North 1,0 Tie Wraps1,693 1,090 1,0 Fiber Board Tags 0.05 Wt' Latent Debris Mass Densit' Size Type

• .(Ibm)

(Ibm/ft)

I__

Dirtand ust 64.91695.68E-5 ft Dirtand ust 64.9169(17.3 p m)

Latent Fiber 2.942.3E-5 ft 29.1 94(7.0 pm)

NL-08-025 Page 22 of 125 Table 3d.3-2 Unit 3 Final Latent Debris Values Latent Debris Type Inside Crane Wall Outside Crane Above Operating Wall Deck Tape and Equipment 13.81 ft2 30.76 ft 2 1.21 ft2Z Labels Tie rapsSouth North 1,1 Tie Wraps2,320 1,425 1,1 Fiber Board Tags 0.02 Wt Latent Debris Mass Densit4 Size Type (Ibm)

(Ibm/ft 5.68E-5 ft Dirt and Dust 212.5 169 (17.3 p m)

Latent Fiber 37.5 94 2.3E-5 ft (7.0 pm)

Entergy Response to Issue 3d.4:

As suggested in NEI guidance all tags, tape, and labels that were determined to be transportable were assumed to arrive on the strainer intact and obstruct an area equivalent to 75% of the total original single-sided surface area. The walkdown report documented approximately 242 square feet of tags and labels that could potentially transport to the Unit 2 sump and obstruct strainer surface area. The walkdown report documented approximately 46 square feet of tags and labels that could potentially transport to the Unit 3 sump and obstruct strainer surface area.

USNRC Issue 3e:

Debris Transport The objective of the debris transport evaluation process is to estimate the fraction of debris that would be transported from debris sources within containment to the sump suction strainers.

1. Describe the methodology used to analyze debris transport during the blowdown, washdown, pool-fill-up, and recirculation phases of an accident.

2. Provide the technical basis for assumptions and methods used in the analysis that deviate from the approved guidance.

3. Identify any computational fluid dynamics codes used to compute debris transport fractions during recirculation and summarize the methodology, modeling assumptions, and results.

4. Provide a summary of, and supporting basis for, any credit taken for debris interceptors.

5. State whether fine debris was assumed to settle and provide basis for any settling credited.

6. Provide the calculated debris transport fractions and the total quantities of each type of debris transported to the strainers.

NL-08-025 Page 23 of 125 Enterpy Response to Issue 3e.1:

The methodology used in the transport analysis is based on the NEI 04-07~ GR for refined analyses as modified by the NRC's safety evaluation report (SER), as well as the refined methodologies suggested by the SER in Appendices Ill, IV, and 'VI. The specific effect of each of four modes of transport was analyzed for each type of debris generated. These modes of transport are:

• Blowdown transport - the vertical and horizontal transport of debris to all areas of containment by the break jet.

• Washdown transport - the vertical (downward) -transport of debris by the containment sprays and break flow.

• Pool fill-up transport - the transport of debris by break and containment spray flows from the refueling water storage tank (RWST) to regions-that may be active or inactive during recirculation.

• Recirculation transport - the horizontal transpott of debris from the active portions of the recirculation pool to the sump screens by the flow through the emergency core coolant system (ECCS).

The logic tree approach was then applied for each type of debris determined from the debris generation calculation. The logic tree shown in Figure 3e. 1-1 is somewhat different than the baseline logic tree provided in the GR. This departure was made to account for certain nonconservative assumptions identified by the SER including the transport of large pieces, erosion of small and large pieces, the potential for washdown debris'to-enter the pool after inactive areas have been filled, and the direct transport of debris to the sump screens during pool fill-up. Also, the.

generic logic tree was expanded to account for a more refined debris size distribution. (Note that some branches of the logic tree were not required for certain debris types).

See the following page for Figure 3e. 1 -1.

N L-08-025 Page 24 of 125 Figure 3e.1-1: Generic debris transport logic tree.

NL-08-025 Page 25 of 125 The basic methodology used for the Indian Point transport analysis is shown below:

1. Based on certain containment building drawings, a three-dimensional model was built using computer aided drafting (CAD) software.

2. A review was made of the drawings and CAD model to determine transport flow paths.

Potential upstream blockage points including screens, fences, grating, drains, etc. that could lead to water holdup were addressed.

3. Debris types and size distributions were gathered from the debris generation calculation for each postulated break location.

4. The fraction of debris blown into upper containment was determined based on the relative volumes of upper and lower containment.

5. The quantity of debris washed down by spray flow was conservatively determined.

6. The quantity of debris transported to inactive areas or directly to the sump screens was calculated based on the volume of the inactive and sump cavities proportional to the water volume at the time these cavities are filled.

7. Using conservative assumptions, the locations of each type/size of debris at the beginning of recirculation was determined.

8. A CFD model was developed to simulate the flow patterns that would occur during recirculation.

9. A graphical determination of the transport fraction of each type of debris was made using the velocity and TKE profiles from the CFD model output, along with the determined initial distribution of debris.

10. The recirculation transport fractions from the CFD analysis were gathered to input into the logic trees.

11. The effects of erosion on the LOCA generated debris were evaluated to determine the potential significance.

12. The overall transport fraction for each type of debris was determined by combining each of the previous steps in logic trees.

13. The transient debris transport to the IR sump during the first 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> after the initiation of recirculation was determined.

3e.1.1 Blowdown Transport The fraction of blowd own flow to various regions was estimated using the relative volumes of containment. Fine debris can be easily suspended and carried by the blowdown flow. Small and large piece debris can also be easily carried by the high velocity blowdown flow in the vicinity of the break. However, in areas farther away from the break that are not directly affected by the blowdown, this debris would likely fall to the floor.

The volumes for the upper containment (including the refueling canal and areas above the 95' elevation operating deck) and for lower containment (including the open area inside the steam generator compartments and annulus below the operating deck) were determined from the CAD model. Because the debris was assumed to be carried with the blowdown flow, the flow split is then proportional to the containment volumes. This resulted in a transport fraction for the fine debris to upper containment of 79%.

The DDTS testing for Boiling Water Reactors (BWRs) showed that in a wetted, highly congested area, approximately 10% of small fiberglass debris would be trapped by miscellaneous structures, and approximately 25% would be trapped by grating. Also, 17% of small fiberglass debris was shown to be captured at 900 turns in a flow path. Although 900 turns might not have to be

N L-08-025 Page 26 of 125 negotiated by debris blown to upper containment at Indian Point, significant bends would have to be made. Therefore, it was estimated that 5% of the small fiberglass debris blown upward would be trapped due to changes in flow direction. The openings in the operating deck at Indian Point are largely covered with grating, so the percentage of small fibrous debris that would be blown to upper containment is estimated to be 51%. The BWR utility resolution guide (URG) (Reference 16) indicates that grating would trap approximately 65% of the small RMI debris blown toward it. This gives a blowdown transport fraction of small RMI debris to upper containment of 28%.

3e.1.2 Washdown Transport During the washdown phase, debris in upper containment could be washed down by the containment sprays. For Indian Point, all of the debris blown to upper containment was determined to be fines and small pieces. It was conservatively assumed that all of this debris would be washed back to lower containment, with the exception of any small piece debris held up on the 95' and 68' elevation gratings as it is washed down. It was also assumed that failed coatings in upper containment would be washed down by the containment sprays.

The debris blown to upper containment was assumed to be scattered around and a reasonable approximation of the washdown locations was made basedion the spray flow split in upper containment. This resulted in a washdown split of 11 % to the steam generator compartments inside the steam generator bio-shields, 21 % to the steam generator compartments through the refueling canal drain, 30% to the steam generator compartments through the miscellaneous grated openings on the operating deck, 26% to the annulus through both the 95' and 68' elevation gratings, and 12% to the annulus through the 95' elevation grating and openings around the support. columns.

Indian Point Unit 2 Multiple levels of grating are present in the Unit 2 Containment. The results of the DDTS testing showed that approximately 40-50% of small fiberglass debris landing on grating would. be washed through the grating due to spray flows. If the only hold up of small piece debris that is credited is for grating at the 95' elevation and the 68' elevation, the transport fraction for small pieces of fiberglass washed down to the annulus would be 13%. The BWR URG indicates that the retention of small RMI debris on gratings is approximately 29%. Therefore, the washdown transport fraction for small RMI to the annulus and to the steam generator compartments is 22% and 53%,

respectively.

Indian Point Unit 3 The results of the DDTS testing showed that approximately 40-50% of small fiberglass debris landing on grating would be washed through the grating due to spray flows. If the only hold up of small piece debris that is credited is for grating at the 95' elevation and the 68' elevation, the transport fraction for small pieces of fiberglass washed down to the annulus would be 13%. The transport fraction for small pieces of fiberglass washed down to the steam generator compartments would be 47%.

3e.1.3 Pool Fill-up Transport During pool fill-up, the flow of water transports insulation debris from the break location to all areas of the recirculation pool. Some of the debris was assumed to transport to inactive areas of the pool including some transport directly to the sump screens as the emergency sump cavities are filled.

NL-08-025 Page 27 of 125 Assuming that fine debris is uniformly distributed in the pool, and the water entering the pooi from the break and sprays is clean (i.e. washdown of debris in upper containment occurs after inactive cavities have been filled), the transport to each of the inactive, cavities -was calculated. (Note that the assumption that debris washdown occurs after inactive cavities have been filled is consistent with the requirements of the SER Section 3.8).

3e.1.4 Recirculation Transport Using CFD The recirculation pool debris transport fractions were determined through CED modeling. To accomplish this, a three-dimensional CAD model was imported into the CFD model, flows into and out of the pool were defined, and the CFD simulation was run until steady-state conditions were reached. The result of the CFD analysis is a three-dimensional model showing the turbulence and fluid velocities within the pool. By comparing the direction of pool flow, the magnitude of the turbulence and velocity, the initial location of debris, and the specific debris transport metrics (i.e.

the minimum velocity or turbulence required to transport a particular type/size of debris), the recirculation transport of each type/size of debris to the sump screens was determined. Two CFD simulations were run for each Indian Point unit to model flow to the IR sump and the VC sump.

A diagram showing the significant parts of the CFD model is shown below in Figure 3.e. 1 -2. The sump mass sink, the modeled break location, the refueling canal drain mass source, and the modeled spray drainage are highlighted.

NL-08-025 Page 28 of 125 Figure 3e.1-2: Diagram of significant features modeled (Figure is for Unit 2. Unit 3 has the same features and are nearly identical)

Modeled spray dupraiaethroughn Modeled SModeled&

aroun nalseellanowsModeledspa conkp starwellselin Modeled bre rist umento mas tunne 0rra inldedinthe following:

Com utaioa MSh:anldri fetrsMu otee soa fietaIh iuainwudaepoiiieylnorn.sFrumethmation wasuse si sthes zdrcinFothtunlprinothmoeaikdmshwthne entranc es Modelng ofContanmentSprayFlows Furomuconsierwatio uefofvriu tec montainmen drwigs ity was mudeigedtapa water would drairatins t

thelpool thr ouglteoolowngpahwys 0

S 0

The grated openings and stairwells in the annulus The gaps in the toe plates around support columns in the annulus The 4-inch refueling canal drain

N L-08-025 Page 29 of 125 The openings around the steam generators

• The grated hatches above the reactor coolant pumps The opening above the pressurizer

• Other miscellaneous openings on the operating deck Note that no drainage through the annular space around the vessel in the refueling cavity to the Reactor Cavity was credited.

Assuming that spray flow is uniform across containment, the fraction of spray landing on any given area can be calculated using the ratio of that area to the overall area. Also, for sprays landing on a solid surface, such as the operating deck, the runoff flow split to different regions, such as the annulus grating and refueling canal, can be reasonably approximated using the ratios of open perimeters where water could drain off.

Modeling of Break Flow:

The water stream falling from the postulated break would introduce momentum into the containment pool that would influence the flow dynamics. This break stream momentum is accounted for by introducing the break flow t 'o the pool at the velocity a freef ailing object would have if it fell the vertical distance from the location of the break to the surface of the pool.

The break stream was in~troduced in the CFD model by defining a flow region populated with mass source particles and setting the flow rate and velocity similar to the containment spray~sources.

The break source was situated near the postulated break location, below the surface of the pool.

This was done to avoid the splashing (which would drastically increase the calculation run time) that would occur if the source was above the pool surface. Splashing is considered to be a negligible mode of transport for all types of debris.

Recirculation Sumps:

Indian Point has two sumps - the IR sump and the VC sump. Since these sumps are in different locations and have different flow rates, separate CFID models were run for the two sumps. The IR sump supplies the internal recirculation pumps, and the VC sump supplies the RHR pumps. Mass sinks used to pull flow from the CFID model were defined for the IR sump and for the VC sump.

A negative flow rate was set for the IR sump mass sink (Unit 2 = 7,100 gpm and Unit 3 = 5,400 gpm) and for the VC sump mass sink (3,700 gpm). E-ach of these flow rates are based upon the maximum low head pump flow and the maximum spray pump flow for each sump at each unit.

This tells the CFD model to draw the specified amount of water from the pool over the entire exposed surface area of the mass sink obstacle. These flow rates represent the maximum recirculation flow for the respective unit which eventually decrease as the time after the accident progresses. These maximum flow rates are conservatively used as steady-state conditions for the CFID model. These flows maximize the TKE and velocities, consequently maximizing the debris transport fractions.

Steady State Metrics:

The CFID models were started from a stagnant state at a pool depth of 1.44 ft for Unit 2 and 1. 19 ft for Unit 3, then run long enough for steady-state conditions to develop. The pool depths represent the minimum containment water level that is present at the beginning of recirculation which maximizes the TKE and velocities. This is conservative because the water level in containment will

NL-08-025 Page 30 of 125 increase with time and resuit in lower TKE and veiocities. A plot,of mean kinetic energy was used to determine when steady-state conditions were reached. Checks were also made of the velocity and turbulent energy patterns in the pool to verify that steady-state conditions were reached.

Debris Transport Metrics:

Metrics for predicting debris transport have been adopted or derived from data. The specific metrics are the TKE necessary to keep debris suspended, and the flow velocity necessary to tumble sunken debris along a floor or lift it over a curb.

The metrics utilized in the Indian Point transport analysis originate from either; NUREG/CR-6772 Tables 3.2, 3.5, or 0.19(a) (Reference 17)

NUREG/CR-6808 Table 5-3 (Reference 18)

NUREG/CR-6916 (Reference 19) or Stokes' Law.

Graphical Determination of Debris Transport Fractions:

The following steps were taken to determine what percentage of a particular type of debris could be expected-to transport through the containment pool to the emergency sump screens.

Colored contour velocity and TKE maps indicating regions of the pool through which a particular type of debris could be expected to transport were generated from the Flow-3D results in the form of bitmap files.

" The bitmap files were overlaid on the initial debris distribution plots and imported into AutoCAD with the appropriate scaling factor to convert the length scale of the color maps to feet.

For the uniformly distributed debris, closed polylines were drawn around the contiguous areas where velocity or TKE was high enough that debris could be carried in suspension or tumbled along the floor to the sump screens.

The areas within the closed polylines were determined utilizing an AutoCAD @ querying feature.

" The combined area within the polylines was compared to the debris-distribution area.

The percentage of a particular debris type that would transport to the sump screens was estimated based on the above comparison.

Plots showing the TKE and the velocity magnitude in the pool were generated for each case to determine areas where specific types of debris would be transported. The limits on the plots were set according to the minimum TKE or velocity metrics necessary to move each type of debris.

Regions where the debris would be suspended were specifically identified in the plots as well as regions where the debris would be tumbled along the floor. Color coding TKE portions of the plots is a three-dimensional representation of the TKE. The velocity portion of the plots represents the velocity magnitude just above the floor level (1.5 inches), where tumbling of sunken debris could occur. Directional flow vectors were also included in the plots to determine whether debris in certain areas would be transported to the sump screens or transported to quieter regions of the pool where it could settle to the floor.

Entergv Response to Issue 3e.2:

Debris erosion rates within the debris transport analysis deviate from the regulatory guidance. The guidance specifies that an erosion fraction of 90% should be used for fiberglass debris. However,

N L-08-025 Page 31 of 125 as described in the justification below, an erosion fraction of 10% was used for fiberglass debris in the recirculation pool.

Some types of insulation debris could erode when subjected to the continuing forces of break or spray flows and pool tu 'rbulence. If the debris breaks down into smaller pieces, it would transport more easily and cause a larger head loss across the sump strainer.

Stainless steel RMI is assumed not to break down into smaller pieces following the initial generation at the beginning of the LOCA. The other insulation debris types with the potential for erosion at Indian Point are Nukon TM, fiberglass, Transco Blanket, Temp-Mat TM, Cal-Sil, and asbestos. The individual fibers and Cal-Sil/asbestos fines would not be subject to further erosion, and the intact pieces of fiberglass are still covered by the original jacketing and therefore would also not be subject to erosion. This leaves the small and large pieces of fiberglass (Nukon TM,

generic fiberglass, Transco Blanket, and Temp-MatTM ) and the chunks of Cal-Sil and asbestos. As discussed in the debris generation calculation the chunks of Cal-Sil and asbestos are not subject to erosion in the recirculation pool.

The DOTS tests have indicated that the erosion of fibrous debris is significantly different for debris directly impacted by containment sprays versus debris directly impacted by break flow. The erosion of large pieces of fibrous debris by containment sprays was found to be less than 1 %, whereas the erosion due to the break flow was much higher. Due to differences in PWR and BWR designs, the results of the erosion testing in the DOTS are only partially applicable. In a BWR plant, a LOCA accident would generate debris that would be held up below the break location on grating above the suppression pool. In the Indian Point plants, however, the break would generate debris that would either be blown to upper containment or blown out away from the break. Most of the debris would not be hung up directly below the break flow where it would undergo the high erosion rates suggested by the DOTS. Any debris blown to u 'pper containment that is not washed~ back down, however, would be subject to erosion by the sprays. Based on the results of the DOTS testing, a 1 % erosion factor was applied for small and large piece fibrous debris held up in 'upper containment. This is consistent with the approach taken for the pilot plant in the SER (Appendix VI). The erosion mechanism for debris in the pool is somewhat different than what was tested in the DOTS. The SER (Appendix 111) describes erosion tests that indicated that the erosion rate of fibrous debris could be on the order of 0.3 percent of the current debris per hour for a pool with a 16-inch depth (compared to 2 percent per hour for a pool with a 9-inch depth). Using the following equation, this gives a total erosion of 7% after 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, and 89% after 30 days.

ferocled rat 1 - (i -

Hours where:

feroded =total fraction of debris eroded rate = erosion rate of current debris per hour Number of Hours = Number of hours debris is subject to erosion The SER points out substantial uncertainties are associated with the erosion testing. However, since the test data showed in general that the erosion consisted primarily of small, loosely attached pieces of fiber breaking off from larger pieces, it is considered reasonable to assume that erosion would taper off after 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. To be conservative, however, the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> erosion was rounded up to 10%. This erosion fraction was applied for both small and unjacketed large fiberglass pieces in the containment pool.

N L-08-025 Page 32 of 125 Entergy Response to Issue 3e.3:

See response to 3e.1 Enterciv Response to Issue 3e.4:

Debris interceptors are not integrated into the Indian Point debris transport analysis. However, flow barriers are designed to force flow down into the reactor cavity (where larger pieces of debris will be retained), through the in-core instrumentation tunnel, and then flow to the annulus through a set.

of crane wall holes next to the VC sump. These are explained in the Upstream Effects Section 31 of this document under the name "flow barrier'. The flow barriers are assumed to be fully blocked so that the velocity through the incore instrumentation tunnel is maximized and consequently the debris transport would also be maximized. This represents a significant conservatism as some fraction of flow would pass through the flow barriers. The amount of debris caught by these flow barriers was not credited for a decreased debris amount at the sump. This represents a significant conservatism as large pieces and intact blankets would likely collect on the coarse screens that make up the barriers.

Enterpy Response to Issue 3e.5:

One hundred percent (100%) of fine debris was assumed to transport to the sump. This represents a significant conservatism as some fraction of fine debris would settle or be captured in stagnant areas of the pool.

Enteray Response to Issue 3e.6:

Transport logic trees were developed for each size and type of debris generated. These trees were used to determine the total fraction of debris that would reach the sump screen in each of the postulated cases. The tables below provide the debris transport fractions and the total quantities of each type of debris transported to the strainers.

NL-08-025 Page 33 of 125 Indian Point Unit 2 Table 3e.6-1 Unit 2 Overall debris transpo~rt fractions s(IR sump)

Debris TYpe Debris Size Tramnsport Fraction Fines to(%

Nukon'`-', Transco Blanket, Small Pieces 15 s Fiberglass Large Pieces 10%

Intact Blankets 0%

Fines 1()0,%

TnpMtMSmall Pieces 15%

Large Pieces 10%ýIC Intact Blanikets 6%

Small Pieces 4%

RMI Large Pieces 0%1 Cal-Sil and Asbestos Piece s 0%

Qualified Co'ating's Inside the ZOI Fines A1M0 Unqualified Coatings.Inside the ZOI Fi~nes 1,00 %

U nqual itied 14 i Temip AlIumfinum li i

10 Outside _theZO~I Chit__________

Unqluaiflied Epoxy/Epoxy Phenolic Chips 39%

Outside tileZOI Unqualified Alkyd Enamiel Outside Chips

.00%

thle ZO I________

Unqualified nrgicZinc OutsideFi&

100%

tileZOI Unqualified White RTV/Bl.ack Caulk Fines I C) e%ý Outside thleZO I___________

DirtlDust Fines I00 Latent Fiber Fines

.1.00

N L-08-025 Page 34 of 125 Table 3e.6-2 Unit 2 Overall debris transport fractions (VC sump) oew-rIvTye Debris SIize Tr-ansport F~raction Fines X)

Nukon"f'I', Transco Blanket, Sml Pics

-1 Fiberglass Large Pieces 10%{

Intact Blankets0 Fines I C 5e Small Pieces I4 TemsM('Large Piece s 10 16 Intact Blankets 0%

Small Pieces 0%91 RNII Large Pieces 0%

Fines 100%

Cal-Sil and Asbestos pieces 0

Qua~lified CotnsInSide the ZOL Fines I100%C Unqualified Coating!s Inside, the ZOI Fjines 100 rl 1>

Unqualified Hligh Temp Aluminum Chips 100 %

Outsidc the ZOI Unqualified Epo~xy/Epo~xy Phenolic Chips

ý3%

Outside the ZOI Unqulalified Alkyd Enamel Outside Chips IM170 t

ihe. ZOI IUnqualified nrgicZinc Outside Fines I YK the ZOI UnquLalified Whit,, RTV/flack Caulk Fines I00 Outside the /-Of Dirt/Dust Fines 10 0 Latent Fiber Fines 100%

The Debris Transport calculations present a 25% transport fraction for tags and labels in anticipation of removal of cable tray tags and labels from containment. -This removal will not be implemented as part of GSI-191 resolution. However, the strainer head loss calculation qualifies both the VC and I R sump strainers for the LBLOCA, ABLOCA, and SBLOCA cases with a 100%

transport fraction for tags and labels.

N L-08-025 Page 35 of 125 Indian Point Unit 3 Table 3e.6-3 Unit 3 Overall debris transport fractions (IR sump)

Debris Type Debris Size Trainsport Fraction Fines 1040%

Small Pieces 1 3%

NuoI, i.,e~asLarge Pieces 1.0%

Intact Blankets 0%

Fines I 0.'0%

Small Pieces 15%

Tm-tiLarge Pieces HAI-Intact Blankets Ole%,

Fines 1040%

Miea olSmall Pieces 15%

Large Pieces 10%

Intact Blankets 0%

Fines 100%

Cal-Sit and AsbestosPies0 Kaowoot Fines 14~)0%

Fiberboard (Marinile)

Fines 10)0%

Qualified Coatings Inside the A() I Fines I (WI%

Unquadifiedi Coatings Insidle thle ZOI Fines I (K0%

Unqualified High Temip Aluminum Chips 1 00%

Outside the Z01 Uncqualified Etpoxy/Epioxy Phenolic Outside the Z~OI Chips Unqualified Alkyd Enamel Outside Chpt4:%

the 701Cip110 DirtlDust Fines II4)0%,

La~tent Fiber Fines H10

N L-08-025 Page 36 of 125 Table 3e.6-4 Unit 3 Overall debris tran'sport fractions (VC sump)

Debris Type Debris Size Tranisport Fr-action Flnes (H0yu%

Snmall Pieces 8

Nukonrt." Fiberglass Large Pieces10 Intact Blankets 0%

Fines 10 Tei-a"S1m1ll1 Pieces 14%

Large Piece 10%:

Intact Blankets0%

Finles 10 Miea

,)lSmall Pieces 14%ý Large Pieces 10%

Intact Blankets 0%

Cal-Sil and AsbestosFie y%

piece's 0%

Kaowool Fines 1 00%to Fiberboamrd dvlarinlie)

Fines I100%M Qualified Coatings Inside tie ZO1 Fines

01) %

Unqualified COatinlgs Inside tile ZO1 Fines 100%

Unqualified High Temp AIlum1inum11

Chips, 100%,

Outsid'e thle Z0O, Unqualifiod Epoxy/Epoxy Phenoilic Cis2 Outside the, Z0OChp UnqIualified Alkyd Enank-l Ou~tside C'hip I %

the ZO I Dirtffius~t Fines I00 Latent Fiber Fines I00 Bounding LOCA conditions for Indian Point include Large Break (LB) and Alternate Break (AB)

LOCA for each of the VC and IR sumps. The insulation materials associated with these are provided in the following tables. The "Debris Generated" column represents the amounts of various materials predicted to be destroyed. While some of this material is predicted to blow upward and be held up by gratings, the full destroyed quantities are assumed to interact with the containment pool for determining chemical effects impacts. The "Debris at VC Sump" and "Debris at IR Sump" columns document the quantities of materials that are predicted to transport to the sump strainers.

NL-08-025 Page 37 of 125 Indian Point Unit 2 Table 3e.6-5 Unit 2 Debris Loads at VC Sump (LBLOCA)

Debris Transport Debris Deri TlvFraction at VC Units Ders yeGenerated

%)

SUMP Nukon (fines) 151,36 1 W 151 36 W____

Nukon (small pi, ces) 576.77 9

51-91 r

Nu kon (large pi4cs 135.73 10 13.57 ftO Nukoii Total 863.86

-____ 216.84 It Thermal-Wrap (fines)

6. 18 100 6.18 S t

Thermal-Wrap (small pieces) 22.53 9

2.03 f

Thermnal-Wrap (large pieces) 6,5 1 10 0.65 7-Therniall-NNrap Total 35,22 8.86 I

Temp-Mat (fines) 6.13 100 6A 13, Terap-NMat (sniall pieces) 23.73 14 3, 32 Wt, Temp-Mat flarge pieces) 25,72 10 2.57 Wt' Temnp-NMt 'rotal 55.58 1 2.02 F______

Cal-Sit (fines) 10,02 100 10.02 ft.,

Cal-Sil (pieces) 0.00 0

0.0 wi Cal-Sill & Asbcstos Totall 10.02

~

10.02 f

QC inside ZOI 526.82 100) 526.82 I bm UQC. inside. ZOI 29.28 10 (X 29.28 1 m VQ IOZ inside ZOI 0.2 3 100X 0.23 Ibmn UQ High Temp. AL outtide ZOl 7.43 100X 7.43 Ibmn UQ Epoxy/Epoxy outside ZOI 394.92 3

11.85 Ibmi UQ Alk-yd outside ZOI 32.29 100 32.29 Ibm UQ White RTV/Black Caulk outside ZOI 168.96 100 168.96 I bml UQ lOZ outside ZOl 191.60 100 191.60 Ibml Non-H )Z Coathmgs Totall I.19.70 776.63 Ib)m1 IOZ Co~atings Totall 191.83 191.83 tIN) lDirtllDust 164.10) 100) 164.91) 11)11 Lateiit Fiber 29.10 119) 29.10)

Ibm

N L-08-025 Page 38 of 125 Table 3e.6-6 Unit 2 Debris Loads at IR Sump (LBLOCA)

Debris Transport Debris Debris Type Generatd Fraction at IR Units M%

Sump Nukon (fines) 151.36 100 151.36 Ut.

Nuk-on (smnall pieces) 576.77 15 86.52 Nukon (large pieces) 135.73 10 13.57 Wt Nuktin Totalt

$63.86

~ 21.45 rvi Thermal-Wrap (fines) 6.18 100 6.18 f~

Therniai-Wrap (qrnall pieces) 22.53 15

-338 W

Thert-al-Wrap (large pieces) 6-51 10 0.65 W

ThernialAWrap TOtal

35. 22)

M021 r

Temp-Mat (fines) 6.13 100

6. 13

.rt3 Temp-NMat (smallI pieces) 23.73 15 3.56 W

Temp-Mat (large pieces) 25.72 10 157 ft'___

[enipNImat Total 55-58 12.26 f t?

Cal-sil (fines) 10.02 100 10,02 wi Cal-SilI (pieces) 0.00 0

0.00 ft-Cal-Sil & Asbestos Total 10.02 10.0)2 I

QC inside ZOT 526.82 100 526,82 bIbm UQC inside ZOI 29.28 100 29-28 Ibin UQ IOZ inside ZOI 0.23 100 0.23 Ibml IJQ High Temip. AL outside ZOI 7,43 100 7.43 Iibm UQ Epoxy/Epoxy outside ZOI 394.92 39 154.02 Ibm U!2 Alkvd outside Z01 32.29 100 32129 bIbm UQ White RTV/Black Caulk witside ZOI 168.96 100)

N66 itm UQ 1OZ outsidleZO1 191.60 100 191,60 Ibm jNii-1(O Z tjitiis

'fjta 1159.7 0 918.80)

Ibm1 101z ctiijIs%

fwhb 1,91.83 191.%3 -

Ib~m D)1t-llhasi I

164.901 11 164.910 1111 Latent Fiber 29.10 PY

NL-08-025 Page 39 of 125 Table 3e.6-7 Unit 2 Debris Loads at VC SUMD (ABLOCA)

Defs Transport Debris Debris Type-Genierated Fraction at VC Units

(%)

Sunip Nukon (fines) 52.90 100 5290o Nukon (small1 pieces) 181.75 9

16.36 ft___3 Nukon (large pieces) 71.22 1o 7.12 ft 3 Nukon Total 30i.87 76.38 1

Therinal-Wrap (fines) 2.66 100 2.66 ft Thermual-Wr-ap (smnall pieces) 6.0-3 9

0.00 ft.1 Thermal-Wrap (large pieces) 9.25i 10 0.00 Therniall-Wrap Total 17.94 2.66 Temp2-Mat (fines) 21.14 100 2.14 WV Te rp-Mat (Sinal Ipieces) 8.4 14 1.15 W

Ten-Mat (largepieces) 9.77 10 0.98 ft "

I emp-XMal Total 20-15 4.27 rt,3 Cal-Si! (fines,)

3.22 100

3. 22 W

Cal-Si! (pieces) 0.00 0

0.00 i.

(lSl&Aslwstos Total 3.22 3.22 f.

QC hiside 701 526.82 100 52 6. 82 Ibm11 UQC inside 701 29.28 lto 29.28 Ibmn UQ 107 inside. ZOI

0. 2)3 100 0.23 Ibmn UQ High Temp. AL outside 701 7.43 100 7.43 Ibmn UQ Epoxv/Epoxy outsid1 ZOT 394.92 3

11.85 Ibmn LIQ Atkyd outside 701 32.29 100 32.29 Ibm I3Q White RTV/Black Caulk outside 701 168.96 100 16&.96 Ibmn UQ IOZ Outside 701 191.60 100 191.60 Ibml Non-It )i Coalings Total 1.159.70 776.63 Ibml 10z Coatings TWtAl 191,83 191.83 Ibm11 IDirt/Ihist 1164.90 l100 164.90 Ibmn Latent Fiber 129.10) 100 29.10 Ibm11

NL-08-025 Page 40 of 125 Table 3e.6-8 Unit 2 Debris Loads at IR Sump (ABLOCA)

Debris Transport Debris Debris Type GeneratedI Fraction at IR Units M%

Sunip Nukon (fines) 52.90 100 52.90 ft' Nukon (small pieces) 18175 15 27.26 W

Nukon (large pieces) 71.22 IL0 7.12 1t1 NkmTtl305.87

~

87-28 Ti Thermal-Wrap (fines) 2.66 100 2166 t

Th6-rna[ Wrap (small pieces) 6.03 15 0.00 ft-,__

Thernial-Wrap (large pie~ces) 9.25 10 0.00 ftj Them mnaIWrap Total 17.94 2.66 TiT Tenip-Mat (tines)

2. ý14 100 2.14 W

Temp-Mat (small pieces)

S.24 15 1.24 3

Temp-Mat (large pieces) 9.77 10 0.98 r

Tem,up.Mat Total 201.15_

4.5 C~al-Sil (fines) 3.2-2 100 3.22 Wt Cal-Sil (pieces) 0.00 0

0.00 f

Cal-Sil & Asb~estos Toa 3.22 3.22 F1*'-

QC inside ZOI 526.82 100 526.8 Ibmi UQC inside ZOI 2)9.-2 8 100 29.28 Ibm UQ IOZ inside ZOI 0.23 100 0.23 Ibm UQ Hig~h Temp, AL outside ZOII 7.41 100 7.43 Ibm[1 UQ Epoxy/Epoxy outside Z01 394,92 39 154.02 Ibm UQ A lkyd outside ZOl 32,29 100 3 2.2-9 Ibm UQ White RTV/Black Caulk out.side ZOI 168.96 to0 168.96 Ibmn UQIOZ Outside ZOl 191.60 100 191.60 Ibmi

,Ron.40z coatings Total 1 159.70_

918.80.

Ibm11 1I)7. Coatings Total 191.83 191.83 lbin 1)irt/1h1%1 164,90) 100.

164.90) 1)11 L.atent Fiber 29.11)0)

29. 10 Ihm The Debris Transport Calculation present a 25% transport fraction for tags and labels in anticipation of removal of cable tray tags and labels. Tags and equipment labels are quantified as 241.63 ft2, and all of it is assumed to transport to the sump. A stacking factor of 75% is credited at the sump.

NL-08-025 Page 41 of 125 Indian Point Unit 3 Table 3e.6-9 Unit 3 Debris Loads at VC Sump (LBLOCA)

DeXbris Transport Debrisa at Sump Debris Type

~

'mae1 Fraction VC.

Scaled Units Geerte)

S ump Qty Nukon (fines) 30&.23 NO0 308.23 Ibm Nukon (small pieces) 1135.59 8

90.85 ibm Nuk-on (large pieces) 327.32 10 3 2).73 IN m1 Nukon Total 1771.14 431.81 48.62 Nil Mineral Wool (fines) 11.27 100 11.27 Ibm Mineral. Wool (smallI pieces) 46.17 14 6.46 l bin Mineral Wool (large pieces) 8.70 10 0.87 Ibm Mineral Wo.1 Tllotal 66.14 1.0 2.09 Ib)m1 Temp-Mat (fin.es) 331,44 100 331.44 lbi Temip-Mat (small pieces')

1304. 19 14 182.59 bi Temp-Mat (large pieces) 689.98 10 69.00 Ibm eIII np Iat T otal 2325.61 5-83.02 65.65 lbIn Cal Sil (tfines) 287.45 100 287.4-5 ibm Cal Sil, (pieces) 257.04 0

0.00 Ibm Ca>-il &d A \\l.stos Total 544.49 287.45 32.37 bibm Epoxy 195 55.58 100 88.00 bibm Epoxy 890 17.99 100 27.50 Ibm Epoxy 6548/7 107 299.35 100 485.62 Ibm Epoxy E-1-7475 131.80 100 285.66 11m UQ Epoxy in ZOI 28.9,1 100 50.75 Ibm LJQ Epoxy outside ZOL 799.35 2

28.06 Ibm UQ Alkyd 29.74 100 50.07 bm UQ Aluminum8.

2 6 100 15.14 Ibm contiiigs Total 1 033.63 1030.80) 116.07 Ib)m1 IDirt/IIust 2:12.50 I00 212.50 23.93 Ibmn Latent Fiber 37.50 100 37.51.)

4.22 Ibm

• ape & Equipment Labels 45.78 WOU 45.78 N/A 11

NL-08-025 Page 42 of 125 Table 3e.6-10 Unit 3 Debris Loads at IR Sump (LBLOCA)____

Debris Transport Debris at Suiflp Debris Type Gienerated Fraction ISup Scaled Units M

Qty N ukon (fine-s) 308.23 100 308.23 Ibm Nukon (small pieces) 1135.59 13 1147.63 Ibmn Nukon (large pieces) 327.32 10 321. 73 Ibmn Nukon Total 1771.14 488.59 17.68 Ibm11 Mineral Wool (fines) 11.27 100 11.27 Ibrn Mineral Wool (smiall pieces)

46. 17 15 6.93 Ibm Mmneral Wool (large pieces) 8,70 10 0..87 Ibrn NMlineral woorr otal 66.14 19.07 0.69 Ibm11 Tempi-Ma t (fines) 331.44-100.

331.44 ibml Temp-Mat (sinal Ipiece s) 1304,19 15 195.63 Ibm Ternip-Mt (large pieces) 689.98 10 69.00 Ibrn Teniii-Mat To~tal 2325.61 596.07 2.1.57 Ibrn Cal-Si I,(fines) 287.45 100 287.45 Ibm Cal-Sil (pieces) 257.034 0

0.00 Ibrn Cal-Sil & AsbestoslTotal 544.49 287.45 10.40

• . ibm Epo~xy 195 55.58 100.

88.00 Ibra Epoxy 890) 17.99 100 27.50 Ibm Epo-x)x 6548/7,107 299.35 1,00 485.62 Ibmn Epoxy E-1-747 5 131.80 100 285.66

~

b UQ Epoxy in ZOI 2&.91 100 50.75 Ibm UQ Epoxy outside ZOI 799.35 28 392.87 Ibm UO Alkyd 29.74 100 50.07 11)1bm UO Aluminunm

8. 26 100 15.14 Ibm CoIatinugs '¶uirogate.Total, 1033.63 1395.61 50.49 Ib)m1 Dii i/Dust 2.12.50

.1()

212.50 7.69 Ib)m1 La ten t Fi beri 37.50) 100f 37.50 1.36 Ibmn J'ap'. & Equtipmen..~t IaxibC 4 5.7.8 100 45.78 N/A 112

NL-08-025 Page 43 of 125 Table 3e.6-1 1 Unit 3 Debris Loads at VC Sump (ABLOCA)

Ders Transport Debris Sump Debris Type Gnrtd Fraction at VC Scaled Units Genraed %)

Sump Qty Nukon (fines) 79.29 100 79.29 ib Nukon (small pieces) 271.75 8

21.74 Ibmn Niikon (large pieces) 151.52

'1) 1.5.15 ib Nukion TOtal 04)2. 56 116.18X 13.09 Ibm Mcinea Wool (fines) 3.29 100 3.29 Ibmn M~ine.ral W60oo (smuall pieces) 13.44, 14 1,88

~

Mine ral WAool (1arge pieces) 2.06 10 0.21 ib Min.ra Wiwii~ o Total

'1I8.79 5.38 0.61, Ibin Temp-Mat (tines) 211.94 100 211.94 bibm Temp-Mat (small pieces) 842.65 14 1,17.97 l bM' Temp-Mat (1arge pie&es) 163.45 10 16.35 Ibm tIemp-Mat Total 1218.04 346.26 39.41, Ibmn--

Cal-Sit Mfines) 142.76 100 142.76 Ibmn Cal-Sit (pieces) 123.07 0

0.00 Ibmn Cal-Sit & Aslhest's ITotal 265.83 142.76 16.09 1Ibm1 Epoxy 195 6.90 100 10.93 Ibml Epoxy 890 4.77 1.00

7. 219 Ibm Epoxy 6548/7 107 71.97 100 116.7.

]b ill Ep.)..xy E-1-7475 31.69 1 1)0 68.68 Ibm UQ Epoxy in ZOL 28,91 100 50.75 ib UIQ Epoxy outside ZOT 799.35 2

28.06

)Ibm 1.JQ Alkyd 29.74 100 50.07

.Ibmn UJQ Aluminum S.26 100 15, 14 Ibmn Cotatin~s Surrograte Total 871.62 347.68 39.17 Ibmn IDirt/1)ust 212,543 100~t 212.50 23.94 Ibmn Latent Fiber 37.51) 100h 37.50 4.23 Ibm Tape & Eciuijiim..nt Labels 45.78 1001 45.78 N/A W______

NL-08-025 Page 44 of 125 Table 3e.6-12 Loads at IR Sumo (ABLOCA)

Unit 3 Debris Debi-s Tranisport Debnis Sunip Debris Type GCenerate Fraction at.IR Scaled Units M%

Sump Qty Nukon (fines')

7 9.2 9 100 79.29 bmi Nukon (smnall pieces) 2171.75 13 35.33 Ib Niikon (larkpepieces) 151,52 10

15. 15 Ibmn Niikon Total 502.%6 129.77 4.70) thin Mineral Wool (fines) 3.29 100

_3.,29 bm Mineral Wool (small pieces) 13.44 15 2.02 bm Mineral Wool (.large pieces) 2.06 10 0.21 ib

'Mineral Wool Total 187 5.51 0.20 Ntin Temip-Mat (fines) 2 11. 94 1 00 211.94 l-ilm Tenip-Mat (small pieces)-

842. 65 15 126.40 Ibmi Temp-Mat (large pieces) 163.45 10 1 6.35 11)I11 Teipcfl~l at. Total 1218X.04 3_54.68 12.83 11)in Cal-Sil (finies) 1422.76 100 142.76 bm Cal-Sil (pieces) 123.07 0

0.00 bm

(:al-SiI & Asbestos Total 265.83 142.76

i. 17 Ibm11 Epoxy 19-5 6.90 100 10.93 bm Epoxy 119o 4.77 100 7.2)

-9 Ibmn Epoxy 65i48/7 107 71.9)7 100 116,75 Ibin Epoxy E-1 -7475

'11.69 100 68.68 Ibm LQ(, Epoxy in ZOI 28,91 100 50.75 Ibmn UQ Epoxy outside ZOI 7-99.35 28 392.87 Ibm I Q Alkyd 29.74 100 50.07 11)111 L. Q Aluiminum 8.2 6 It00 15,14 J-ibm Coaiig~ Sln urr~ogate Tot1al S71.62 712.49 2ý5.78 Ibmn D)mrtIIDust 212.511) 100) 212.50 7.69 thin1 I ikul F iber 37.50 I 000 37.51)

'1.36 lbin TaIpe & EquItipmentII Labels 45.78 1 00 45.78 NVA rt 2 UISNRC Issue Af Head Loss and Vortexing The objectives of the head loss and vortexing evaluations are to calculate head loss across the sump strainer and to evaluate the susceptibility of the strainer to vortex formation.

1. Provide a schematic diagram of the emergency core cooling system (ECCS) and containment spray systems (CSS).

2. Provide the minimum submergence of the strainer under small-break loss-of-coolant accident (SB LOCA) and large-break loss-of-coolant accident (LB LOCA) conditions..

3. Provide a summary of the methodology, assumptions and results of the vortexing evaluation. Provide bases for key assumptions.

4. Provide a summary of the methodology, assumptions, and results of prototypical head loss testing for the strainer, including chemical effects. Provide bases for key assumptions.

NL-08-025 Page 45 of 125

5. Address the ability of the design to accommodate the maximum volume of debris that is predicted to arrive at the screen.

6. Address the ability of the screen to resist the formation of a "thin bed" or to accommodate partial thin bed formation.

7. Provide the basis for the strainer design maximum head loss.

8. Describe significant margins and conservatisms used in the head loss and vortexing calculations.

9. Provide a summary of the methodology, assumptions, bases for the assumptions, and results for the clean strainer head loss calculation.

10. Provide a summary of the methodology, assumptions, bases for the assumptions, and results for the debris head loss analysis.

11. State whether the sump is partially submerged or vented (i.e., lacks a complete water seal over its entire surface) for any accident scenarios and describe what failure criteria in addition to loss of net positive suction head (NPSH) margin were applied to address potential inability to pass the required flow through the strainer.

12. State whether near-field settling was credited for the head-loss-testing and, if so, provide a description of the scaling analysis used to justify near-field credit.

13. State whether tempera ture/viscosity was used to scale the results of the head loss tests to actual plant conditions. If scaling was used, provide the basis for concluding that boreholes or other differential-pressure induced effects did not affect the morphology of the test debris bed.

14. State whether containment accident pressure was credited in evaluating whether flashing would occur across the ktrainer surface, and if so, summarize the methodology used to determine the available containment pressure.

Entercjv Response to Issue 3f.1:

Schematics of the Emergency Core Cooling System are included in Attachment 2.

Entergy Response to Issue 3f.2:

Indian Point Unit 2 Under a small break loss-of-coolant accident (SBLOCA) the VC sump strainer extension (located inside the containment annulus) is not fully submerged. The difference between the top of the strainer, 47.21 feet, and the minimum water level, 46.86 feet, is 4.2 inches. The VC sump strainer itself (located on the inside of the crane wall) is fully submerged during the SBLOCA.

The IR and VC sump strainers (including the annulus extension) under a large break loss-of-coolant accident (LBLOCA) are fully submerged. The difference between the minimum water level, 47.44 feet, and the top of the VC strainer, 47.21 feet, is 2.8 inches. Additional water in the RWST above the minimum Technical Specification level is not credited.

Indian Point Unit 3 The strainer under a small break loss-of-coolant accident (SBLOCA) is fully submerged given that

-the RWST low level setpoint is adjusted or an equiivalent amount of water is available through reanalysis. The difference between the minimum water level, 46.54 feet, and the floor of containment, 46.00 feet, is 6.48 inches with the strainer fully below the floor level.

N L-08-025 Page 46 of 125 The strainer under a large break loss-of-coolant accident (LbLOCA) is fully submerged. The difference between the minimum water level, 47.07 feet, and the floor of containment, 46.00 feet, is 12.84 inches. Additional water in the RWST above the minimum Technical Specification level is not credited.

Entergy Response to Issue 3f.3:

Vortices are a potential cause for air ingestion into the IR pump suction and RHR recirculation suction lines. Because these suction lines are encased in the plenum box and are not exposed to open water, except during SBLOCA conditions, air ingestion could only potentially occur at the Top-Hats.

Conservatisms within the vortex evaluations for the VC sump strainer include the following:

For the SBLOCA case, the 2 inch drawdown was calculated using a flow rate of 1350 gpm (run out flow of two high head pumps) versus a more realistic lower value (approximately 1100 gpm) for the maximum flow rate of a SBLOCA For the LBLOCA case, the drawdown accounts for the localized effects above the sump which will not be as sever e with the spread out annulus portion at the initiation of recirculation. The flow will favor the Top-Hats within the pit that have more submergence.

A normalized flow across all of the Top-Hat modules is assumed. At Unit 2, at the start of recirculation, due to internal losses, a majority of the flow will pass through the pit section of the strainer before it loads with debris. Therefore, for some period of time the annulus strainers will not draw the full normalized flow. The water level will continue to increase as the RWST is drawn down by the containnment spray pumps(s). Therefore as debris loads on the strainer and forces more flow to the annulus portion, the water level will simultaneously increase providing more margin to the maximum allowable approach velocity.

The perforated plate Top-Hats are expected to disrupt any rotational flow that could lead to vortex formation. The Top-Hat strainer design spreads the IR and RHR pump flow over a much greater area (entire area of the IR and VC sump pits and at Unit 2 a very large area within the containment annulus) than the traditional PWR sump strainers. In addition, the knitted wire mesh bypass eliminator should provide additional protection against drawing a vortex into the Top-Hat modules.

Finally, the cruciform at the ends of the Top-Hat modules'should act to break up or minimize any vortex that could travel the length of the Top-Hat modules before entering the flow plenum.

The break flow, containment spray and any debris that is generated inside the crane wall is directed into the in-core instrumentation tunnel entrance and down into the reactor cavity. At first, the water level is below the bottom of the dividing wall and the surface of the pool is continuous.

However, as the reactor cavity fills, the surface of the pool is divided by a wall. At this point any buoyant debris below the in-core instrumentation tunnel exit area could transport toward the sump as the flow travels up the in-core instrumentation tunnel and outside of the crane wall. Any buoyant debris that is subsequently washed down or dislodged will be trapped inside the crane wall. Therefore, the amount of buoyant debris is limited and is not expected to challenge the effectiveness of the strainer.

Indian Point Unit 2 Testing also confirms that vortices will not occur if certain maximum allowable approach velocities based on the geometry of the strainer are met. With consideration for a 2" drawdown during a

NL-08-025 Page 47 of 125 LBLOCA, the Unit 2 Top-Hats are qualified to meet this criterion with 0.8" of coverage at a greater than expected flow rate of 6000 gpm.

For an SBLOCA (3 inch and smaller), the IR and VC sump strainers are fully submerged with the exception of the Unit 2 VC strainer extension in the containment building annulus. An in-depth vortex evaluation shows that vortex formation for the SBLOCA will not occur provided the head loss limitations are met which were developed through a methodology using the submergence Froude number and consideration of design limits recommended in Reg. Guide 1.82.

Indian Point Unit 3 Vortices were observed to form on the surface of the water approximately 11 hours1.273148e-4 days <br />0.00306 hours <br />1.818783e-5 weeks <br />4.1855e-6 months <br /> into the test.

These vortices resided primarily'on the water surface and did not extend to the surface of the Top-Hat strainer modules. The maximum vortex diameter was 3 in. and their residence time was less than 5 minutes. This test was conducted using approximately 6 inches of water above the Top-Hats. No other tests experienced any vortices of any kind. Therefore air ingestion by vortices is not an issue if a minimum of 6 inches of water depth is maintained above the Top-Hats in the plant.

Entercjv Resp~onse to Issue 3fA4 The purpose of the Indian Point testing, as described in the. head loss testing reports was to collect and record differential p ressure, temperature and flow rate data while building a bed of a specific quantity and mixture of debris across a strainer array representative of a portion of the larger arrays that would be installed at Indian Point. The debris mixtures used included both fibrous insulation debris and particulate debris representative of that present at Indian Point. The

,prototypical testing did not -include chemical effects which will be addressed in response to issue 3o.

The specific objectives for the Indian Point prototypical strainer array testing are stated below:

Measure and record the head loss at conditions representative of the maximum expected particulate to fiber ratio to demonstrate that the debris does not cause high head losses due to the formation of a thin-bed on the strainer.

Measure and record the head loss at conditions representative of the maximum expected debris loads to demonstrate the performance of the strainer as the interstitial volume both inside and between the strainer modules is filled.

The strainer modules that were tested are a double Top-Hat design developed by Enercon Services, Inc. The strainers consist of hollow concentric cylinders fitted with the Bypass Eliminator mesh in the annulus and mounted on a 15-in, square base. The cylinders are comprised of stainless steel perforated plate. The Top-Hat modules that were tested are dimensionally similar to a portion of the modules that would be installed at Indian Point. For the tests, the Top-Hat strainers were mounted to a plenum assembly and arranged horizontally in a 3x3 array. The Top-Hat array was placed in a test tank capable of flow circulation~ with walls representing a pit configuration and/or adjacent strainer modules.

The basic approach to testing includes the following inherent assumptions:

• The performance of the reduced (3x3) strainer array is representative or conservative when compared to the full strainer array. This is reasonable as a larger array will tend to load more non-uniformly creating lower total head loss.

N L-08-025 Page 48 of 125 The testing performed in room temperature tap water can be scaled appropriately to various temperatures of reactor coolant water. Again, this is a reasonable assumption as temperature effects on head loss are well documented (e.g. NUREG/CR-6224), and tap water and reactor coolant water have essentially identical physical (density, viscosity) characteristics.

Short term testing is representative of the performance of the sump over a longer mission time. To minimize any impact of this assumption, acceptance criteria are set to require stable head loss before terminating the test.

The strainer array testing successfully collected differential pressure, flow rate, and temperature data for two types of tests: 1) Tests with a debris bed containing high particulate to fiber mass ratios and 2) Full load fiber and particulate tests. Head loss versus debris quantity curves were developed by the analysis. In addition, the testing successfully demonstrated that the debris by pass eliminators would have a small impact on the Indian Point strainer head loss.

Enterpy Response to Issue 3f.5:

Indian Point Unit 2 The use of debris sump scaling to represent the full VC sump strainer conditions in the plant is predicated upon the fact that the total flow was able to circulate through the entire replacement strainer array. In turn, the relative uniformity of the flow through the debris depends upon the extent to which the interstitial volume of the replacement strainer array is or is not filled with debris. It is valid to conclude that the flow is essentially uniform through the strainer array if there is sufficient interstitial volume that is not filled and available for flow. Otherwise, in the event that that the interstitial volume is completely filled, the flow is forced to flow downward through the top layer of debris. This would cause the fluid velocity through the debris bed to be significantly higher, resulting in head loss across the debris bed to be significantly higher.

The strainer head loss evaluation addresses the ability of the design to accommodate the maximum volume of debris predicted to transport to the screen. Strainer array testing has shown (Figure 3f.5-1) that there was sufficient interstitial volume that was unfilled and available for flow, thereby validating the conclusion that flow through the prototype strainer array was relatively uniform. The post-test photograph (Figure 3f.5-1) shows that approximately one-third of the interstitial volume was completely open and fully accessible for flow at the end of the test.

Therefore, it can be reasonably concluded that the water was not limited to flowing downward through the top layer of debris, but was distributed in a relatively uniform manner throughout the prototype strainer array. Consequently, a significant head loss was not observed as a result of non-uniform flow distribution. These conclusions are applicable to the full VC sump strainer array for the following reasons. First, the prototype strainers were enclosed in a pit-style configuration which closely modeled the geometry of the VC sump pit strainers. Second, the debris was introduced directly on top of the prototype strainers during testing, which is a representative testing condition and accurately modeled the debris transport to and accumulation onto the VC sump pit strainers.

To further support the fact that the strainer array testing conservatively modeled the debris loading onto the VC pit strainers from a sump scaling standpoint, the relative open volume that is available for debris for both the test and plant pit configurations was computed. This volume is defined as the overall volume in the pit minus the volume of the Top-Hat strainers and plenum for each configuration.

Comparing the values of the sump pit and occupied volume for the VC sump pit, shows that in the test configuration, the strainers were more confined than in the plant. Hence, the test configuration

NL-08-025 Page 49 of 125 bounded the potential for debris compaction and associated non-uniform flow distribution versus the plant configuration. Since there was significant interstitial volume accessible for flow at the end of the test in the test configuration, there will be equal or more interstitial volume accessible for flow in the plant. Thus, testing has shown that the use of debris sump scaling to represent the full VC sump strainer conditions in the plant is appropriate and accurate.

Figure 3f.5-1 Unit 2 Front view of the Top-Hat array with full debris load Indian Point Unit 3 The strainer head loss evaluation will address the ability of the strainer to accommodate the volume of debris predicted to transport to the sump. Strainer array testing has shown that there was sufficient interstitial volume that was unfilled and available for flow, thereby validating the conclusion that flow through the prototype strainer array was relatively uniform. The post-VC ABLOCA photograph (see Figure 3f.5-2) shows that approximately one-half of the interstitial volume was completely open and fully accessible for flow at the end of the test. Therefore, it can be reasonably concluded that the water was not limited to flowing downward through the top layer of debris, but was distributed in a relatively uniform manner throughout the prototype strainer array.

Consequently, a significant head loss was not observed as a result of non-uniform flow distribution.

These conclusions are applicable to the VC sump strainer array subject to ABLOCA conditions for the following reasons. First, the prototype strainers were enclosed in a pit-style configuration which closely modeled the geometry of the VC sump pit strainers. Second, the debris was introduced directly on top of the prototype strainers during testing, which is a conservative testing condition and accurately modeled the debris transport to and accumulation onto the VC sump pit strainers.

NL-08-025 Page 50 of 125 To further support the fact that the strainer array testing conservatively modeled the debris loading onto the VC pit strainers from a sump scaling standpoint, the relative open volume that is available for debris for both the test and plant pit configurations was computed. This volume is defined as the overall volume in the pit minus the volume of the Top-Hat strainers and plenum for each configuration.

Comparing the values of the sump pit and occupied volume for the VC sump pit, shows that in the test configuration, the strainers were more confined than in the plant. Hence, the test configuration bounded the potential for debris compaction and associated non-uniform flow distribution versus the plant configuration. Since there was significant interstitial volume accessible for flow at the end of the test in the test configuration, there will be equal or more interstitial volume accessible for flow in the plant. Thus, testing has shown that the use of debris sump scaling to represent the VC sump strainer conditions in the plant is appropriate and accurate.

Figure 3f.5-2 Unit 3 Front view of the Top-Hat array with full debris load

NL-08-025 Page 51 of 125 Enteravy Response to Issue 3f.6:

The "thin-bed effect" is defined as the relatively high head losses that occur across a uniform thin bed of fibrous debris that can sufficiently filter particulate debris to form a dense particulate debris bed. The minimum thickness of fibrous debris needed to form a thin bed has typically been estimated at 1/8-inch thick based on the nominal insulation density. The thin-bed effect is typically seen in testing of a strainer or screen with a simple geometry such as a flat plate. However, strainer designs with a complex geometry are more likely to load non-uniformly precluding the formation of a thin bed such as the case with the Indian Point Top-Hat design. "Thin-bed exploratory testing" during the head loss testing confirmed this conclusion. As seen in Figure 3f.6-1, testing recorded no high head losses for thinner (1/8" - 1/2") fiber beds.

Figure 3f.6-1 Unit 2 Comparison of Steady-State Differential Pressure from Test Series #1 and #3 Comparison of Hood Loss Data from Test Series #1 and #3 OAS5 0.4-025 -

0.3+-

9.5.

a 0.2.

F4__

'j-41--Test#3 ------------------------------------------------- ---------

OAS 4 OA -

0.05.

0 0.,125 0.25 01315 05 01620 0.70 Debris (uoanfty~ftadner Surface Area (in.)

0.057 1

1.125 Note: Debris thickness is equal to the debris quantity divided by the strainer surface area.

Enterav Response to Issue 3f.7:

The debris head loss is added to the clean screen head loss to determine the total head loss (excluding chemical effects head loss which is discussed in Issue 3o) across the sump screens due to post-LOCA debris. The ability to sustain this head loss is then assessed through fulfillment of the acceptance criteria as determined by the NPSH margins and structural loading requirements. See response to issue 3f. 10 for comparison of values.

The head losses presented in this submittal currently do not include chemical effects. The chemical effects evaluation is currently in progress and, when determined, the chemical effects bump up factors will be utilized in the determination of strainer head loss.

N L-'08-025 Page 52 of 125 Entergy Response to Issue 3f.8:

For the SIBLOCA case, the 2 inch drawdown was calculated using a flow rate of 1350 gpm versus a more realistic lower value (approximately 1100 gpm) for the maximum flow rate of a SIBLOCA.

The head loss testing included several conservatisms that provide additional margin with respect to the strainer head loss. The debris loads themselves have conservatism built into them based on the fact that each debris type represented the highest quantity generated by one of four breaks (The highest amount of each type of debris was used out of the four LBLOCA breaks, meaning that the full load test quantities are actually a worst case scenario constructed from the worst of four separate breaks). The debris was added directly on top of the strainer array to ensure that the maximum debris reached the prototype test strainers. Conservatisms unique to each unit are described below.

Indian Point Unit 2 Conservatisms within the vortex evaluations for the VC sump strainer include the following:

• For the LBLOCA case, the drawdown accounts for the localized effects above the sump which will not be as severe at IP-2 with the spread out annulus portion at the initiation of recirculation. The flow will favor the top hats within the pit that have more submergence.

• .A normalized flow across all of the top hat modules is assumed. At the start of recirculation, due to internal losses, a majority of the flow will pass'through the pit section of the strainer before it loads with debris. Therefore, for some period of time, at IP-2, the annulus strainers will not draw the full normalized flow. The water level will continue to increase as the RWST is drawn down by containment spray and as LOCA steam in the VC atmosphere condenses. Therefore, as debris loads on the strainer and forces more flow to the annulus portion, the water level will simultaneously increase providing more margin to, the maximum allowable approach velocity.

The nominal screen area (1119.5 ft2) was used to compute the test tank flow rates and debris scaling factors rather than the effective area of 114.1 ft2. This results in a conservatively high flow rate as the test plan used a bounding approach velocity and a conservatively high screen area.

The final flow sweep point for Test Series #1 and #3 was replaced with the steady state point after the Test 1 F and 3F debris additions. This conservatively bounds the upper flow sweep data point and maximized the calculated turbulent contribution to the steady state head loss. The steady state head loss values were conservatively corrected upward for flow and temperature using a correction equation, that utilized an 80%-20% laminar-turbulent split. Similarly, the head loss was conservatively corrected downward for flow using a 100% laminar equation. These corrections over-predict the final head loss values.

Indian Point Unit 3 The nominal screen area (135.9 ft2) was used to calculate debris quantities, while the effective screen area (114.1 ft2) was used to compute the test tank flow rates. This results in an appropriately bounding flow rate. The steady state head loss values were conservatively corrected upward for flow and temperature using a correction equation that utilized a 50%-50%

laminar/turbulent split. See details in Response to Issue 3f. 10. These conservative corrections were used to over-predict the final head loss values.

N L-08-025 Page 53 of 125 Entergy Resp~onse to Issue 3f.9:

In order to determine the clean strainer head loss (CSHL), the following basic steps were followed:

" The strainer effective surface area is determined.

The head loss through a single Top-Hat is calculated using the correlation derived from testing between the Top-Hat head loss and the annulus (outer and inner) flow. Each individual head loss is calculated. The larger head loss of the two annuli is taken, conservatively, because total resistance in parallel systems is always less than the larger of the two.

" The head loss due to the flow traveling through the support structure of the Top-Hats is calculated in the following way: Flow through the support structure (referred to as channel or manifold depending on the situation) is broken down into nodes and the appropriate junctions are modeled according to their hydraulic configuration as Wyes, elbows, flow contractions, expansions and obstructions such as I beams. The length between nodes is used to calculate the wall friction. Flow entering the manifold from the individual Top-Hats is modeled as a 90 degree elbow at the initial node point and as a Wye intersection for the subsequent Top-Hats along the channel. If more than one Top-Hat is attached to the same nodal point, the combined flow is modeled as one junction. Major obstructions are considered and significant changes in cross-sectional area are modeled as sudden expansions and/or contractions.

• -In order to estimate head loss through, the manifold, a hydraulic diameter is calculated for each section that has a unique cross-sectional area and configuration.

• The largest head losses experienced by a Top-Hat and its associated channels and manifolds are summed to produce the most conservative clean strainer head loss.

Important assumptions in the clean strainer head loss include:

Steady, incompressible flow is assumed.

The lowest sump water temperature is assumed to be constant at 600F. For the dynamic head losses, this is slightly conservative. Since water at higher temperatures (characteristic of post-accident sump temperatures) would exhibit lower viscosity, a conservatively low water temperature would result in lower Reynolds numbers, and consequently higher friction factors.

It is assumed for this analysis that the containment pressure is 14.7 psia. This assumption is reasonable because the water properties associated with this pressure are not significantly affected by the pressure term.

The head loss'across the strainer Top-Hat modules including the knitted wire mesh bypass eliminator feature as a function of the Top-Hat annulus velocity has been determined by prototype testing. Based on this testing, the following Top-Hat head loss correlation can be calculated for the IR and VC sump strainer modules:

Y =0.4487X2 _ 0.0307x + 0.0335 where:

x = annular flow velocity through strainer assemblies (ft/sec) y = Top-Hat module head loss (feet of water column)

NL-08-025 Page 54 of 125 Based. on this correlation, the following is the Top-Hat module head loss for a few selected flow velocities:

Table 3f.9-1 Top-Hat module head loss Outer Inner Annulus Annulus Sump Flow Velocity Head Loss Velocity Head Loss 9p!I..

fps ft fps Ft IR 4428 0.111 0.036 0.108 0.035 WON00 0.1507 0.039 0.146 0.039 3600 0.410 0.096 0.396 0.092 VC 5500 0.627 0.190 0.604 0.179 WOW___

bx00

.684 0.222 0.659 0.208 Indian Point Unit 2 The IR and VC sump clean strainer head loss values are shown in the table below:

Table3f.9-2 Unit 2 IR and VC sump c~lean strainer head loss IR Sump VC Sump.

Flow Head Flow Head Loss Loss GPM FT GPM FT 1000 0.039 10.00 0.130 1350 0.044 1350 0.209 2500 0.071 2000 0.417 2625 0.075 2834 0.798 2750 0.079 3000 b.890 2875 0.084 3528 1.215 3000 0.088 3700 1.332 3125 0.093 4000 1.549 3250 0.098 4500 1.984 3375 0.103 4749 2.164 3500 0.108 5000 2.393 3958 0.129 5500 2.885 4000 0.131, 6000 3.423 4300 0.146 4428 0.153 5565 0.223 6000 0.254 7086 0.341 7200 0.351

NL-08-025 Page 55 of 125 Indian Point Unit 3 The I R and VC sump clean strainer head loss values are shown. in the table below:

Table 3f.9-3 Unit 3 1IR and VC sump clean strainer head loss IR Sump VC Sump Flow Head Loss Flow Rate Head Loss GPM FT GPM FT 1000 0.043 1000 0.076 1350 0.052 1350 0.114 2000 0.075 2000 0.211 2600 0.104 2500 0.312 3000 0.127 3000 0.434 3342 0.150 3700 0.646 3530 0.164 4000 0.748 4000 0.201 4500 0.937 4300 0.228 4749 1.041 5000 0.296 5000

1. 147ý 5400 0.340 5500 1.384 6000 0.413 6000 1.639 Enterav Response to Issue 3f. 10:

The sump screen head loss due to the post-LOCA debris accumulated on the sump screens was determined based upon the results from the Indian Point strainer array test reports. The sump scaled debris quantities for each Indian Point sump were compared to the testing quantities to establish the, relationship between the measured head losses obtained during testing and the worst-case sump screen head losses that could occur at each unit during post-LOCA operation.

These bounding head losses serve as the design basis for the IR and VC sump screens in containment.

The NUREG-6224 correlation was used to establish either a debris load adjustment factor or debris load adjustment equations. The debris quantity adjustments are necessary to account for

.the difference between the debris loads used in the test program and the Indian Point sump scaled debris loads. The choice of either a debris load adjustment factor or debris load adjustment equations depends on whether the solidity limit was reached. The NUREG-6224 correlation is used to develop the debris quantity adjustment methodology because it is the most defendable analytical tool available that relates head loss, debris bed properties and fluid flow properties.

Planned revisions of the Debris Head Loss calculations are expected to use a method consistent with NRC guidance.I

NL-08-025 Page 56 of 125 The temperature corrections were performed to fac.ilitate comparison of the predicted Indian Point head loss values with NPSH margins at an elevated temperature (204.70F) and the SBLOCA and structural loading conditions at a reduced temperature (60'F). The culmination of these analyses will produce,a bounding head loss value for each condition (LBLOCA for IR and VC sumps, SBLOCA for IR and VC sumps, and structural loading criterion) for comparison to the various acceptance criteria. The performance of the sump strainers was deemed satisfactory if the bounding head losses for each condition met the corresponding acceptance criteria.

The debris bed head loss depends largely on the composition of the debris mixture that is determined to potentially reach the sump. In addition, the debris bed head loss is dependent upon the debris size and debris characteristics.

Assumptions and conservatisms used in the head loss calculation include:

" At pool temperatures greater than 204.7 0F, the NPSH margin remains the same.

" The minimum containment pool temperature was assumed to be 600F.

" It was assumed that the head loss due to a mixture of debris materials can be determined by summing the contribution of each debris component. (eg. CSHL + Debris Head Loss +

Chemical Effects Head Loss = Total Head Loss)

" It was assumed that all tapes, tags and labels (latent debris) in the ZOI fail and contribute to the debris source term. As stated in NEI 04-07; all failed latent debris that is determined transportable is assumed to arrive at the sump screens intact and obstruct an area equivalent to 75% of the total original single-sided surface area. Note that the sump scaling factors when calculating debris quantities did not include obstruction due to tags and labels.

This is because it was observed in the strainer array testing that the debris bridged across adjacent prototype Top-Hat strainer modules and created a thick debris bed (>1/2"). Due to this observation, it was assumed that any tags and labels that reached the sump screens for these analytical cases would be completely absorbed within the fibrous and particulate debris and would provide a negligible contribution to debris thickness. Increase in flow through the debris bed due to tag obstruction was considered.

it was assumed that due to the geometrical characteristics of the tie wraps in containment the impact of the tie wraps on the strainer head loss was negligible.

The exact fiber characteristic size for the latent debris is unspecified in the SER. The size of the Nukon individual fibers, 7.0 pm, will be assumed. This is in agreement with the approach specified in the Section 3.5.2.3 of the SER, that appropriate commercial-grade fiberglass insulation properties can be, utilized.*

The microscopic density of latent fiber is assumed to be 1.5 g/cm3 as specified in the SER.

This is equal to 94 Ibm/ft3.

The particle diameter of latent particulate (Dirt/Dust) is assumed to be 17.3 pmn based on the specific surface area of 106,000 ft-1 for use in the NUREG/CR-6224 correlation as specified in the SER.

" The strainer areas were reduced by 3% to conservatively account for up to a 3% void fraction present in the debris bed.

The maximum bed solidity is assumed to be 50%. Test data for BWR debris beds show maximum bed solidities around 35%. Using 50% provides some additional margin in a conservative direction since a greater bed solidity will restrict water flow and create a higher head loss.

Data collected during testing flow sweeps at the final debris load conditions shows that the laminar term is dominant. Based on this assessment, it is judged that for fiber loads greater than or equal tol.4 lb m/ft2, the measured head loss can be conservatively corrected upward for fl~ow or.

NL-08-025 Page 57 of 125 temperature using an 80% laminar term and a 20% turbulent term. To correct downward for flow, a correction using a 100% laminar term will be used. This is conservative due to the fact that this methodology will under-predict the change in head loss and thus will report higher predicted head losses at lower flow rates.

The predicted head loss for the IR sump LBLOCA case is less than the NPSH margin allotted for the IR sump strainers and is therefore an acceptable h 'ead loss result. Similarly, the predicted head loss for the VC sump LBLOCA case is less than the NPSH margin allotted for the VC sump strainers, and is therefore an acceptable head loss result. Since the VC sump strainer head losses were limiting, the structural loading acceptance criterion was evaluated using representative VC sump strainer head losses. The VC sump strainer head loss is less than the structural loading limit for the Indian Point replacement strainer array assemblies. These results are acceptable and applicable to the full strainer installations for the VC sump and the extension outside the crane wall.

For both sump configurations, the debri s source term is dominated by particulate debris. In addition, the-measured data from the strainer array test reports conservatively bound any head loss that could be achieved with varying fiber quantities in the range of a high particulate to fiber mass ratio.

Indian Point Unit 2 The results of the head loss calculations for Unit 2 are presented in the table below:

Table 3f.10-1 Unit 2 Total predicted head losses and available marain Total Predicted Head Loss*

Head Loss Limit Margin Case (ft-water)

(ft-water)

(ft-water)

IR Sump LBLOCA (3,958 0.214 1.3 (NPSH Margin) 1.086 gpm)

VC Sump LBLCOA (3,528 4.237 8.5 (NPSH Margin) 4.263 gpm)

StutrlLoad (2,834 6.668 6.93 (Structural 0.262 gpm & 600F)

Lmt Structural Load (3,528 4.237.

7.20 (Structural 2.963 gpm & 204.70F)

Limit)

• Chemical effects not included at this time

N L-08-025 Page 58 of 125 Indian Point Unit 3 Preliminary results of the head loss calculations for Unit 3 are presented in the table below:

Table 3f. 10-2 Unit 3 Total predicted head losses and available margin Total Predicted Head Loss*

Head Loss Limit Margin Case (ft-water)

(ft-water)

(ft-water)

IR Sump LBLOCA (5,263 0.530 0.84 (NPSH Margin) 0.310 gpm)

VC um LLCA 3,86 1.15 6.66 (NPSH Margin) 5.51 gpm)____

Structural Load (2,312 1.96.93 (Structural 53 gp

& 600 F) 1.9Limit) 5.34___

Structural Load (3,586 1.15 7.20 (Structural 6.05 gpm & 204.70 F)

Limit)_____

• Chemical effects not included at this time Entergy Response to Issue 3f.1 1:

With the exception of the Unit 2 SBLOCA case (unsubmerged VC strainer in the annulus), no vents or other penetrations exist in the strainer control surfaces that might connect the strainer's internal volume to the containment atmosphere above the containment minimum water level. The Strainer Head Loss Calculation determines that the maximum sustainable flow rate through the partially submerged strainer, based on the hydraulic static head is 1,688 gpm. Because the maximum VC sump flow rite during a SBLOCA is only 1,350 gpm, the sump is not susceptible to flow starvation.

The internal Volume is specifically evaluated for air ingestion which show that vortex formation for the SBLOCA is unlikely to occur based on a methodology using the submergence Froude number and consideration of design limits recommended in Reg. Guide 1.82.

Enterpy Response to Issue 3f. 12:

No near-field settling was credited for head loss testing and evaluation.

Entergy Response to issue 3f. 13:

The head loss test data was scaled to actual plant conditions using temperature and viscosity. Test Data was collected by measuring head loss at different approach velocities to determine the laminar and turbulent flow fractions and the appropriate correction equations. While determined using flow variations, the head loss effects due to temperature variations for laminar and turbulent flow regimes are well understood, and appropriate head loss equations were developed. This enables the measured head loss to be conservatively adjusted for different flow rates and temperatures than those observed during testing. These equations were presented in the Test reports. Since appropriate debris surrogates were used, these formulas can be applied to various debris mixtures that may exist at Indian Point that differ from those that were tested. Therefore, the strainer array test results can be safely scaled to the arrangements at Indian Point.

Boreholes were not observed during post test inspection of the Indian Point debris beds. Bed dislocations were observed during testing (as reflected in the head loss readings), but the debris bed quickly reformed and the previous head loss was recovered or largely recovered. As stated

N L-08-025 Page 59 of 125 above, flow sweep data was used to develop semi-empirical equations based on Indian Point specific conditions. Boreholes and/or differential pressure induced effects are most likely to occur during the flow sweeps due to the high velocities, and consequently high head losses, present.

Therefore, any debris-bed morphology effects are inherently included in the corrections and are less likely to form at the lower design flow rates.

Enterciv Respjonse to Issue 3f. 14:

The void fraction analyses contain the complete methodology used to calculate the volume of air bubbles and associated water vapor (steam voids) present in the water downstream of the strainer surface. The SER suggests a maximum void fraction of 3% to prevent cavitation problems within the sump pumps. Containment accident pressure was credited in evaluating the extent of flashing across the strainer surface. Without credit for containment accident pressure, the sump water would flash at the surface of the containment pool.

Indian Point Unit 2 The containment temperature and pressure generally decrease from the start of recirculation. Per Containment Integrity Analysis, the containment pressure and temperature decrease to approximately 42.9 psig (57.6 psia) and 2620F respectively at time of recirculation. The void fraction analysis conservatively used 250OF and 50 psia for containment temperature, and pressure respectively.

The I R sump,, with a sump temperature of 2540F, a containment atmosphere of 250OF and 50 psia, a containment flood elevation 1.85 feet above the strainer and a strainer head loss of 2.64 ft-lbf/Ibm, is es~timated to have a 0.25% void fraction of vapor downstream of the strainer, which meets the 3%/ acceptance criteria.

The VC sump, with a sump temperature of 2540F, a containment atmosphere of 250OF and 50 psia, a containment flood elevation 0.04 feet above the strainer and a strainer head loss of 2.45 ft-lbf/lbm, is estimated to have a 0.33% void fraction of vapor downstream of the strainer, which meets the 3% acceptance criteria.

Indian Point Unit 3 The containment temperature generally decreases from the start of recirculation. Per Containment Integrity Analysis, the containment pressure and temperature decrease to approximately 38.24 psig (52.94 psia) and 254.14'F respectively at time of recirculation, 1623.8 sec. The analysis will conservatively use 250OF and 50 psia for containment temperature, and pressure respectively.

The I R sump, with a sump temperature of 2570F, a containment atmosphere of 250OF and 50 psia, a containment flood elevation 0.83 feet above the strainer and a strainer head loss of 3.13 ft-lbf/lbm, is estimated to have a 0.56 % void fraction of vapor downstream of the strainer, which meets the 3% acceptance criteria.

The VC sump, with a sump temperature of 2570F, a containment atmosphere of 250OF and 50 psia, a containment flood elevation 0.86 feet above the strainer and a strainer head loss of 2.43 ftilbf/lbm, is estimated to have a,0.51 % void fraction of vapor downstream of the strainer, which meets the 3% acceptance criteria.

N L-08-025 Page 60 of 125 USNRC Question 3g:

Net Positive Suction Head (NPSH)

The objective of the NPSH section is to calculate the NPSH margin for the ECCS and CSS pumps that would exist during a loss-of-coolant accident (LOCA) considering a spectrum of break sizes.

1. Provide applicable pump flow rates, the total recirculation sump flow rate, sump temperature(s), and minimum containment water level.

2. Describe the assumptions used in the calculations for the above parameters and the sources/bases of the assumptions.

3. Provide the basis for the required NPSH values, e.g., three percent head drop or other criterion.

4. Describe how friction and other flow losses are accounted for.

5. Describe the system response scenarios for LB LOCA and SB LOCAs.

6. Describe the operational status for each ECCS and CSS pump before and after the initiation of recirculation.

7. Describe the single failure assumptions relevant to pump operation and sump performance.

8. Describe how the containment sump water level is determined.

9. Provide assumptions that are included in the analysis to ensure a minimum (conservative) water level is used in determining NPSH margin.

10. Describe whether and how the following volumes have been accounted for in pool level calculations: empty spray pipe, water droplets, condensation and holdup on horizontal and vertical surfaces. If any are not accounted for, explain why.

11. Provide assumptions (and their bases) as to what equipment will displace water resulting in higher pool level.

12. Provide assumptions (and their bases) as to what water sources provide pool volume and how much volume is from each source.

13. If credit is taken for containment accident pressure in determining available NPSH, provide description of the calculation of containment accident pressure used in determining the available NPSH.

14. Provide assumptions made which minimize the containment accident pressure and maximize the sump water temperature.

15. Specify whether the containment accident pressure is set at the vapor pressure corresponding to the sump liquid temperature.

16. Provide the NPSH margin results for pumps taking suction from the sump in recirculation mode.

Enterpy Response to Issue 3cp.1 and 3q.2:

Indian Point Unit 2 The range of flow rates examined in the head loss analysis are 3,958 gpm (1 pump at full recirculation) to 7,086 gpm (2 pumps at full recirculation) and 2,834 gpm (at the beginning of recirculation) to 3,528. gpm (at full recirculation) for the I R sump and the VC sump respectively.

These flow rates correspond to the most limiting net positive suction head (NPSH) margins.

The NPSH margin evaluation included the following assumptions:

• The screen loss is neglected for the maximum performance cases. This is conservative since it maximizes flow.

NL-08-025 Page 61 of 125

• The blocked nozzles spray ring header resistance is used for the minimum performance cases since this minimizes recirculation spray performance.

For conservatism, strainer certification assessments will be performed at a sump temperature of 204.70F to compare to the minimum NPSH margins for the Unit 2 recirculation pumps. Further justification for the use of 204.70F is located in response to Issue 3g.14.

The results of the Indian Point Unit 2 Minimum Post-LOCA Containment Water Level Calculation are provided below for both LIBLOCA and SIBLOCA events. A summary of key assumptions is located in response to issue 3g.9.

Table 3g.1-1 Unit 2 Post Accident Containment Water Levels Break Location Case Water Level (feet) after Start of Double Ended Pump Suction Break Recirculation 47.63 Maximum Containment Atmosphere Temperature after CS Minimum Safeguards Switchover*

48-55 after CS 47-92 switchover" Double Ended Pump Suction Break End-of-Event 48-25 after Start of Double Ended Guillotine Break Recirculation 47.44 in the Pre-SSUrizer Surge Line after CS r",1aximurn Containment Atmosphere TemnperatUre 13witchove~r' 48.36 Minimum Safeguards after CS 48.08 switchover" No Sprays, after Start of 47.08 Recirculation Small Break LOCA

Sprays, RCS Not Fully Depressurized~

after Start of 46M8 Recirculation

Sprays, after CS 47.77 Switchover

• Steam Generators and Pressurizer are not assumed to be refilled after the RCS blowdown, simulating conditions with SI Recirculation Sprays still operating and high containment pressure and temperature.

• • Steam Generators and Pressurizer ar~e assumed to be refilled after the RCS blowdown, simulating long term conditions with SI Recirculation Sprays secured and with low containment pressure and temperature.

• • This small break water level is limited to breaks that are less than 3 inches. The SI accumulators are expected to discharge for breaks greater than or equal to 3 inches. Also, the RCS holdup for breaks greater than or equal to 3 inches is expected to be no greater than the RCS holdup for a postulated la~rge break LOCA.

Indian Point Unit 3 The flow rates examined in the head loss analysis are 5,263 gpm (2 pumps with containment spray) and 2,484 gpm (11 pump without containment spray), and 4,124 gpm (1 pump with containment spray) for the IR sump and 3,586 gpm (11 pump with containment spray) for the VC sump. These flow rates correspond to the most limiting net positive suction head (NPSH) margins.

N L-08-025 Page 62 of 125 For conservatism, strainer certification assessments will be performed at 204.70F to compare to the minimum NPSH margins for the Unit 3 recirculation pumps. Further justification for the use of 204.70F is located in response to Issue 3g.14.

The NPSH margin evaluation included the following assumptions:

• For the maximum performance cases (maximum sump level), the sump screen loss is neglected, which is conservative since it maximizes the flow.

The results of the Indian Point Unit 3 Minimum Post-LOCA Containment Water Level Calculation are provided below for both LBLOCA and SIBLOCA events. A summary of key assumptions is located in response to issue 3g.9.

Table 3g. 1-2 Unit 3 Post Accident Containment Water Levels Break Location Case Water Lever (feet) after Start of Double Ended Pump Suction Break Recirculation 47.25 Maximum Containment Atmosphere Temperature after CS Minimum Safeguards Switchover*

47.97 after CS.

48.59 switchover"*

after Start of 47.33 Double Ended Pump Suction Break Recirculation Maximum Containment Atmosphere Temperature after CS 481.01 Maximum Safeguards Sv/itchover*

after CS 48.63 Switchover**

Double Ended Pump Suction Break End-bf-Event 48.23 after Star t of 47.07 Pressurizer Surge Line Break Recirculation Maximum Containment Atmosphere Temperature after'CS 48.06 Minimum Safeguards Switchover*

after CS 48.33 switchover**

No Sprays, after CS 4&6.1 Switchover Small Break LOCA

Sprays, RCS Not Fully Depressurized after Start of 46.54 Recirculation

Sprays, after CS 47.73 Switchover

• Steam Generators and Pressurizer are assumed to be refilled after the RCS blowdown, simulating long term conditions with SI Recirculation Sprays secured and with low containment pressure and temperature.

• • Steam Generators and Pressurizer are not assumed to be refilled after the RCS blowdown, simulating conditions with SI Recirculation Sprays still operating and high containment pressure and temperature.

• • • This small break water level is limited to breaks that are less than 3 inches. The SI accumulators are expected to discharge for breaks greater than or equal to 3 inches. Also, the RCS holdup for breaks greater than or equal to 3 inches is expected to be no greater than the RCS holdup for a postulated large break LOCA.

NL-08-025 Page 63 of 125 Enteray Response to Issue 3g.3:

Net-positive suction head (NPSH) calculations were performed to establish the NPSH margins in the absence of the sump strainers and collected debris (i.e., pump NPSH margins were calculated by subtracting the NPSH available from the NPSH required, without including headloss through the EGOS strainer and collected debris). The required NPSH values were determined by the pump manufacturers based upon a 3 percent decrease in developed pump head.

Entergy Response to Issue 3qj.4:

In the evaluation of piping systems Westinghouse utilized the Fathom and NEWKFAC design codes. Fathom was used to calculate hydraulic performance and NEWKFAC to calculate resistance coefficient, equivalent length (LID), pressure drop and friction factor for a given pipe segment and flowrate. The Westinghouse calculations used very conservative flowrates as well as the lowest VC sump water levels to obtain the NPSHA values. In general, system resistances were minimized conservatively to obtain flowrates but were maximized to obtain NPSHA.

Enteray Response to Issue 3q.5:

The engineered safety feature (ESF) systems include two separate sumps, the recirculation sump (IR sump) and the containment sump (VC sump) for collecting liquid discharged during the design basis accident. After the injection operation, coolant spilled from the break and water collected from the containment spray are cooled and returned to the reactor coolant system by the recirculation system.

When the break is large, depressurization occurs due to the large rate of mass and energy loss through the break to containment. In the event of a large break, the recirculation flow path is, initially within the containment. The system is arranged so that the recirculation pumps take suction from the recirculation sump in the containment floor and deliver spilled reactor coolant and borated refueling water back to the core through the residual heat exchangers. The system is also arranged to allow either of the residual heat removal pumps to take over the recirculation function.

The residual heat removal pumps would only be used if backup capacity to the internal recirculation loop is required. Water is delivered from the containment to the residual heat removal pumps from the separate containment sump inside the containment. For the purposes of head loss analysis, the cases that will produce the highest head loss are always examined. Generally, the highest flow rate would produce the highest head loss. During an LBLOCA, at about 6.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> after the break, the system is aligned for hot leg recirculation. This entails the use of the recirculation pumps to provide suction boost to the High Head Safety Injection (HHSI) Pumps. These pumps then provide cooling flow to both hot and cold legs of the RCS.

For small breaks, the depressurization of the reactor coolant system is augmented by steam dump from and auxiliary feedwater addition to the steam generators. For the smaller breaks in the reactor coolant system where recirculated water must be injected against higher pressures for long-term cooling, the system is arranged to deliver the water from residual heat removal heat exchangers to the high-head safety injection pump suction and by this external recirculation route to the reactor coolant loops. If this flow path is unavailable, an alternate flow path is also provided. The alternate flow path includes the VC sump, the RHR pumps, and the middle HHSI pump. It bypasses the RHR heat exchangers with coreNC cooling provided by the Containment Fan Cooler Units and the recirculation spray (if available). Thus, if depressurization of the reactor coolant system proceeds slowly, the safety injection pumps may be used to augment the flow-pressure capacity of the recirculation pumps in returning the spilled coolant to the reactor. In this system configuration, the

N L-08-025 Page 64 of 125 recirculation pump (or residual heat removal pump) provides flow and net positive suction head to the operating safety injection pumps. At Unit 2, in order to prevent safety injection pump flow in excess of its maximum allowable (i.e., runout) limit, variable flow orifice valves are installed at the discharge of the safety injection pumps and the hot and cold leg motor-operated isolation valves are preset with mechanical stops based on data from operational flow testing to limit system maximum flow capability. At Unit 3, to prevent excess pump flow, manual throttling valves were installed and set in specified positions in selected cold and hot leg branch lines.

Entergy Response to Issue 3q.6:

There are seven pumps employed for RCS LOCA accident mitigation where the use of the Containment Building sump(s) is required. The seven ECCS pumps are the two Recirculation

.Pumps within the Containment, three High Head Safety Injection Pumps and two Residual Heat Removal Pumps in the Primary Auxiliary Building (PAB). There are also two Containment Spray Pumps in the PAB which only draw fluid from the RWST.

Prior to the recirculation phase is the injection phase. Provided power is available and no failures occur; the three HHSI Pumps, two RHR Pumps, and two Containment Spray Pumps (provided a hi-hi containment pressure signal is generated) will be delivering flow from the RWST.

For Recirculation Phase, the three HHSI Pumps and two RHR pumps are ultimately secured during the switchover process to the Recirculation Pumps. The Containment Spray pumps, if actuated, can continue drawing down the RWST to its low level cut off point in part to satisfy the minimum spray time for dose reduction and to increase the Containment flood level above the sumps. The Recirculation pumps will be started to initiate low head recirculation. If this cannot be accomplished due to high RCS backpressure or other reasons, the Recirculation Pump's discharge will then be.routed to-the, HHSI pump(s) -to provide additional head. If continued containment Spray is required and the RWST is exhausted (thereby preventing use of the Containment Spray pump which only draws from the RWST), part of the recirculation flow can be diverted off to the spray headers. If the recirculation pumps are or become unavailable, either of the two RHR Pumps can be aligned to draw from the Containment sump to provide Low head recirculation, or feed into the HHSI Pumps as needed in place of the Recirculation Pumps.

Enterpy Response to Issue 3a.7:

The basic single failure assumptions with r egard to the ECCS and CSS are identical at Unit 2 and Unit 3. At both Units these systems are currently required to fulfill their safety-related functions with a single active failure during the injection phase of the post-accident period or with an active or passive failure during the recirculation phase (assuming no active failure has occurred during injection). A License Amendment Request (LAR) is being prepared that will request the NRC to approve a change to the Unit 2 / Unit 3 Licensing Basis concerning the timing of the passive failure. At present, the passive failure is postulated to occur immediately at recirculation initiation; the LAR intends to change this occurrence time to a minimum of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> into the accident scenario.

A single failure re-evaluation of Unit 2 and Unit 3 ECCS and 055 was performed in light of GSI-191. Currently, for certain single failures (either active or passive) durin~g any portion of recirculation, a switchover from the IR sump to the VC sump must be implemented to maintain core

/ VC cooling. At Unit 2, an active failure was identified that would disable the IR sump as a source of coolant for Hot Leg recirculation. For Small and Alternate size LOCAs, this would not represent a problem since the debris load could be adequately handled by the VC sump (i.e., RHR Pump

N L-08-025 '

Pag~e65 of 125 INPSH margin maintained) at any time during the entire recirculation phase. For a LB LOCA, it was demonstrated by analysis that the debris removed at the IR sump prior to switching over to the VC sump (at approximately the Hot Leg recirculation switchover time) was sufficient to permit the latter sump to function as required. At Unit 3, no single active failure was identified that would require a switchover from the IR sump to the VC sump. With the approval of the LAR for the change in passive failure timing (24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> into the event), the single failure re-evaluation has concluded that

.both at Unit 2 and Unit 3, the ECCS and CSS could fulfill their safety functions with, a passive failure.

Enteray Response to Issue 3g.8:

The post-LOCA minimum containment flood water is determined using the following methodology:

1. A correlation is developed for the relationship between the containment water level and the required water volume based on the Unit 2 and Unit 3 free volume calculations.

2. The quantity of water added to containment from the Refueling Water Storage Tank, SI Accumulators and the Reactor Coolant System is calculated for each of the breaks.

3. The quantity of water diverted from the containment sump is calculated. Water is diverted from the containment sump by the following effects:

Steam holdup in the containment atmosphere Water volume required to fill the Safety Injection, Residual Heat Removal and Containment Spray Piping that is empty prior to the LOCA Additional mass of water that must be added to the RCS due to the increase in the water density at the lower sump water temperature (versus the RCS temperature prior to the LOCA)

• Condensation on surfaces

• Water volume required to fill the RCS steam space

• Water in transit from the Containment Spray nozzles and the break to the Containment Sump

• ECCS leakage outside of containment

• Refueling canal holdup

• Miscellaneous holdup volumes throughoutý containment

4. Given the net mass of water added to the containment floor based on items 2 and 3 listed above, the post-LOCA containment water level is calculated using the correlation developed in item 1.

The containment water level is calculated for the following breaks:,

Double Ended Guillotine Break of RCS Loop Piping Double Ended Guillotine Break of the Pressurizer Surge Line or a SI Accumulator Line Small Break LOCA - RCS Pressurized After Break (small break < 1 ft2)

These three breaks were chosen in order to encompass a wide range of potential breaks. The containment water level was calculated for both large breaks and small breaks because the ECCS flow requirements from the recirculation and containment sump and the potential debris generated following a LOCA will be distinctly different for each scenario.

The time after the. LOCA can also be shown to have an impact on containment water' level. Among other things, the time after the LOCA will impact the volume of water transferred from the RWST to the containment, accumulation of water in various holdup volumes in containment, RCS shrinkage and water held up in the containment atmosphere. For this reason the containment water level is determined for the time. that recirculation begins, the time that Containment Spray is switched over

NL-08-025 Page 66 of 125 to SI Recirculation Spray, the time at which recirculation spray is secured, a No Spray case for SIBLOCA, and an end-of event LBLOCA scenario.

Enterpy Response to Issue 3Q.9:

The following assumptions provided the basis to ensure a minimum containment water level is calculated:

• ~Since it is conservative to maximize the hold up of steam in the containment atmosphere, the peak containment temperature after start of recirculation for the minimum ECOS safeguards case is used in the water level calculation for small break and large break LOCAs.

• RCS conditions are conservatively assumed to be saturated. This maximizes the mass of water in the atmosphere and minimizes the mass on the containment floor.

• Portions of ESE piping are assumed to not be filled with water prior to emergency operation. Filling the drained portions of these systems will divert water from the containment sum ps.

• To conservatively minimize the mass of water within the SI accumulators that could spill into containment, the temperature is assumed to be equal to the maximum initial containment air temperature consistent with the accident analysis of 130'F. This approach is conservative because the density of water decreases with increasing temperature.

• For non-flowing condensation, a conservative film thickness of 0.003 inch can be reasonably assumed. The use of a 0.003-inch non-flowing film thickness for all containment surfaces, except for the containment walls (in which a thicker flowing film thickness is used), is conservative because it is expected that many of these surfaces will not support any film due to the turbulence that is expected inside containment.

For conservatism when calculating holdup of water due to water-in-transit, all of the containment spray flow is assumed to originate from the upper ring of containment spray nozzles. In addition, all of the injection flow is assumed to flow from a break at the top of the pressurizer surge line. This is the highest potential break elevation in the RCS that could allow full RHR flow through the break.

For a break in the ROCS loop piping, it is conservatively assumed that the reactor vessel (up to the top of the hot and cold leg piping), RCS loop piping (including reactor coolant pump internals), and pressurizer surge line are refilled with ECOS inventory at the time of ECOS switchover to recirculation.

The refueling cavity hold up assumes all flow goes through the drain, not through the annular space around the Reactor Vessel. This represents a significant volume that does not contribute to the water level. Also, the spray flow value is conservatively high, as is the friction factor for flow through the drain. This maximizes the volume contained in the refueling cavity.

Additional assumptions are made that result in conservative VC levels, but these are minor contributors as compared to the assumptions cited above.

Enterav Reso~onse to Issue 3a. 10:

See Responses to Issues 3g.8, 3g.9 and 3g.12.

NL-08-025 Page 67 of 125 Enterpy Response to Issue 3a.1 1:

The volumes occupied by structures, equipment, and equipment supports, etc. will displace water and result in a higher pool level. Examples of such equipment include, concrete walls, accumulator tanks and piping, curbs, and supports for the major RCS components. These volumes are subtracted from the available volume at each elevation in containment to obtain the net free volume at each level. The net free volume versus elevation curve is then used to determine the water level.

For both Unit 2 and 3, all assumptions used in these calculations were designed to maximize the free volume at each level while minimizing the occupied volumes in order to provide a conservative water level for NPSHA values for the ECCS pumps.

Enterav Response to Issue 3g. 12:

Indian Point Unit 2 The following design inputs provided the basis for water sources and their volumes to determine the minimum containment water level:

The net water volume to fill containment to elevations of 46' and 49' 6" is 96,409 and 381,584 gallons, respectively.

The minimum water volume maintained in the RWST is greater than or equal to 345,000 gallons. This level includes allowances for instrument accuracy, margin and the unusable volume in the RWST.

The manual process of switchover to recirculation is initiated after the RWST low-low level alarm setpoint is reached which is maintained between 74,200 gallons and 99,000 gallons.

During and after switchover to recirculation, water continues to be drawn from the RWST for accident mitigation. Water level setpoints provide a minimum water volume of 229,000 gallons during the injection phase and 68,000 gallons during and after the transition to the recirculation phase. Additionally a sufficient quantity of water is allowed for instrument inaccuracies, additional margin and water that is unavailable from the bottom of the tank.

The maximum RWST temperature is 110 OF.

There are four SI accumulators that have a minimum volume of 723 ft3. The total accumulator volume includes the average accumulator line volume (47 ft3); therefore volume of 770 ft3 for each accumulator was used.

" The Containment average air temperature during normal plant operation is maintained > 50 F and! *130 F.

The pressurizer minimum level was conservatively assumed to be 30% of span.

The minimum RCS volume is 10,885 ft3 based on a 30% pressurizer level.

Indian Point Unit 3 The following design inputs provided the basis for water sources and their volumes to determine the minimum containment water level:

• The net water volume to fill containment to elevations of 46' and 49' is 94,564 and 345,186 gallons, respectively.

• The minimum water level maintained in the.RWST is 35.4' which corresponds to a water volume of approximhately 342,200 -gallons. This level includes allowances for instrument accuracy, margin and the unusable volume in the RWST.

NL-08-025 Page 68 of 125 The manual process of switchover to recirculation is initiated after the RWST low level alarm setpoint is reached which is maintained between 10.5' and 12.5'. During and after switchover to recirculation, one Containment Spray pump continues to draw from the RWST until the water level reaches the low-low level alarm setpoint at 1.5' to ensure the correct sump pH. These water level setpoints provide a minimum water volume of 195,800 gallons during the injection phase and 66,700 gallons during and after the transition to the recirculation phase.

The maximum RWST temperature is 1 100F.

There are four SI accumulators that have a minimum water volume of 775 ft3.

The Containment average air temperature during normal plant operation is maintained > 50 F and *ý 130 F.

The pressurizer minimum was conservatively assumed to be 23.1 % of span.

The minimum RCS volume is 10,784 ft3 based on a 23.1 % pressurizer level.

The Post-LOCA Containment Water Level is lowest for the Small Break LOCA (SBLOCA) where the RCS does not fully depressurize and sprays are activated. The minimum level occurs after the start of recirculation. For the small line break, the inventory within the SI accumulators is not credited because the operators could potentially isolate the SI accumulators prior to the RCS pressure dropping below the nitrogen cover-pressure of the accumulators. For the No Spray SBLOCA case, the RWST inventory that is dedicated for Containment Spray is not credited since the sprays will not be activated. It should be pointed out that the water level for the SBLOCA cases is conservatively determined using the containment analysis for a large break LOCA since the containment analysis was not performed for a SBLOCA.

Entergv Response to Issue 3q. 13:

The NPSH available calculations were performed using assumptions consistent with guidance in NEI 04-07 and its associated SER for minimizing the effect of containment over-pressure on the NPSH calculation results. For the minimum NPSH margin case, no containment overpressure was credited (i.e., containment pressure was assumed to equal the saturation pressure corresponding to the sump water temperature).

Entergy Response to Issue 3a. 14:

The post-LOCA pool water temperature that provides the-minimum NPSH margin to the IR and Residual Heat Removal (RHR) pumps is 204.7 OF. Based on Regulatory Position 1.3.11 of Regulatory Guide 1.82, the minimum NPSH margin for the IR and RHR pumps occurs at the saturation temperature (204.70F) corresponding to the Unit 2 and Unit 3 Technical Specification minimum containment pressure (-2 psig) prior to the accident. At pool temperatures below 204.70F, the containment pressure exceeds the saturation pressure of the sump pool providing additional NPSH margin. In addition, the vapor pressure of water at lower temperatures is less than its corresponding value at 204.7 0F; this phenomenon provides additional NPSH margin. This assertion can be verified in any set of standard engineering steam tables. At pool temperatures greater than 204.70F, the NPSH margin remains the same (since it is assumed that the vapor pressure of the sump pool is equal to the containment pressure) but the debris head loss decreases due to the fact that the viscosity of the recirculation fluid decreases. Therefore, for conservatism, strainer certification assessments will be performed at 204.70F to compare to the minimum NPSH margins for the Indian Point recirculation pumps.

N L-08-025 Page 69 of 125 Indian Point Unit 2 The Void Fraction Calculation was performed at the maximum sump temperature after the start of recirculation, 2540F. The corresponding predicted containment pressure is 59.4 psia. However, to minimize the containment pressure, the Void Fraction Calculation used a conservative value of 50 psia. When determining the NPSH margin it is assumed that the containment pressure is equal to the vapor pressure of water. For example, at a temperature of 2540F a vapor pressure of approximately 32.0 psia is used when determining NPSH available.

Indian Point Unit 3 The Void Fraction Calculation was performed at the maximum sump temperature after the start of recirculatio 'n, 2570F. The corresponding predicted containment, pressure is 56.3 psia. However, to minimize the containment pressure, the Void Fraction Calculation used a conservative value of 50 psia. When determining the NPSH margin it is assumed that the containment pressure is equal to the vapor pressure of water. For example, at a temperature of 2570F a vapor pressure of approximately 33.7 psia is used when determining NPSH available.

Enterpv Response to Issue 3ai.15:

At pool temperatures greater than 204.70F, it is assumed that the vapor pressure of the sump pool is equal to the containment pressure. At pool temperatures below 204.70F, it is assumed that the containment pressure is equal to atmospheric pressure.

Entergv Response to Issue 3-g.16:

• The NPSH margins for a LBLOCA are provided in the tables below. These NPSH margins do not include the final calculated head loss contributed by the sump screens, debris head loss or chemical effects. Final NPSH margins will be included after values for debris and chemical effects head losses are finalized.

NL-08-025 Page 70 of 125 Indian Point Unit 2 Table 3g. 16-1 Unit 2 LIBLOCA NPHMargins*

Sump Alignment Pumps Sump Flow

-NPSH Margin Rate (gpm)

(ft-water)

Internal Recirculation Start of Recirculation One (1) IR 3127 2.9 Pump Internal Recirculation Start of Recirculation Two (2) 1IR 5565 2.9

_______________Pumps Full Recirculation Two (2) IR Internal Recirculation (with Recirculation Pumps 6615 3.1 Spray)

(1 RHR-HX)

Full Recirculation Oe()I Internal Recirculation (with Recirculation One(1mp 3958 1.3 Spray.)

Pm Full Recirculation Two (2) 1IR Internal Recirculation (with Recirculation Pumps 7086 2.5 Spray)

(2 RHR-HXs)

Vapor Containment Start of Recirculation One (1) RHR 2834 13.7 Pump Full Recirculation One (1) RHR 32 Vapor Containment (with Recirculation Pump 32 Spray)

• Alignments and NPSH margins subject to revision Indian Point Unit 3 Table 3g. 16-1 Unit 3 NPHMargins*

Sump NPSH Sump Alignment Pumps Flow Rate Margin (ft-(gpm)_

water)

Internal Full Recirculation (with Two (2) 1IR 52308 Recirculation recirculation Spray)

Pumps.

52308 Vapor Full Recirculation (with One (1) RHR 3586 6.66 Containment Recirculation Spray)

Pump Internal Str.fRciclto One (1) IR 2484 2.6 Reiclto tr fRecirculation Pump Vapor Str fRciclto One (1) RHR 2312 15.14 Containment Str fRcruain Pump Internal Full recirculation (wLth One (1) IR 414*

Recirculation recirculation Spray)

Pump

NL-08-025 Page 71 of 125

• Alignments and NPSH margins subject to revision

"*Note: This case assumes a very conservative head loss. Finalized calculations are expected to show favorable results.

USNRC Issue 3h:

Coatings Evaluation The objective of the coatings evaluation section is to determine the plant-specific ZOI and debris characteristics for coatings for use in determining the eventual contribution of coatings to overall head loss at the sump screen.

1. Provide a summary of type(s) of coating systems used in containment, e.g., Carboline CZ 11 Inorganic Zinc primer, Ameron 90 epoxy finish coat.

2. Describe and provide bases for assumptions made in post-LOCA paint debris transport analysis.

3. Discuss suction strainer head loss testing performed as it relates to both qualified and unqualified coatings and what surrogate material was used to simulate coatings debris.

4. Provide bases for the choice of surrogates.

5. Describe and provide bases for coatings debris generation assumptions. For example, describe how the quantity of paint debris was determined based on ZOI size for qualified and unqualified coatings.

6. Describe what debris characteristics were assumed, i.e., chips, particulate, size distribution and provide bases for the assumptions.

7. Describe any ongoing containment coating condition assessment program.

Entercjv Response to Issue 3h.1:

Indian Point Unit 2 The types and amounts of coatings used in the Unit 2 containment are included in the Debris Generation Calculation. The types of coating systems used in containment are presented below:

Qualified Coatings:

Keeler & Long 6129 Keeler & Long 4129 Keeler & Long 4000 Keeler & Long 6548/71 07 Keeler & Long 5000 Keeler & Long D-1 Unqualified / Unacceptable Coatings:

Inorganic Zinc High Temp Aluminum Alkyd Enamel Epoxy/Epoxy Phenolic White RTV / Black Poly. Caulk

NL-08-025 Page 72 of 125 Indian Point Unit 3 The types and amounts of coatings used in the Unit 3 containment are included in the Debris Generation Calculation. The types of coating systems used in containment are presented below:

Qualified Coatings:

Carboline 195 Carboline 890 K&L 6548/7107 K&L E-1 -7475 Unqualified / Unacceptable Coatings:

High Temp Aluminum Alkyd Enamel Epoxy/Epoxy Phenolic Enteray Response to Issue 3h.2:

The following assumptions related to fine particulate debris, including paint chips, were made in the debris transport analysis:

a. It was assumed that the settling velocity of fine particulate debris (insulation, dirt/dust, and paint particulate) can be calculated using Stokes' Law.

Basis: This is a reasonable assumption since the particulate debris is generally spherical and would settle slowly (within the applicability of Stokes' Law).

b. It was assumed that the fines generated by the LOCA blast would be transported to upper containment in proportion to the volume of upper containment compared to the entire volume.

Basis: This is a reasonable assumption since fine debris generated by the LOCA jet would be easily entrained and carried with the blowdown flow.

c. It was assumed that the debris washed down from upper containment by the spray flow would remain in the general vicinity of the location where it is washed down until recirculation begins.

Basis: This is a reasonable assumption since there is no preferential pool flow direction during pool fill-up after the in-core instrumentation tunnel/reactor cavity and the sump cavities have been filled. Also, this assumption is somewhat conservative since the local turbulence caused by the sprays would increase the potential for debris to transport from these locations.

d. It was assumed that the fine debris that is not blown to upper containment would be uniformly distributed in the recirculation pool at the beginning of recirculation.

Basis: This is a reasonable assumption, since the flow during pool fill-up would carry the fine debris to all regions of the pool.

NL-08-025 Page 73 of 125 Enterciv Response to Issue 3h.3:

Sil-Co-Sil - ground silica was the surrogate material used in suction strainer head loss testing to simulate the mechanical behavior of both'qualified and unqualified coatings debris. Details of head loss testing as it relates to DBA qualified and unqualified coatings are located in Response to Issue 3f.4 and 3f.5.

Enterpy Response to Issue 3h.4:

The Sil-Co-Sil particulate debris surrogate material was selected based on a comparison of the microscopic densities of the plant materials. Epoxy and alkyd coatings densities at plants range from 94 lb/ft3 to 98 lb/ft3 per the NEI GR. Inorganic zinc coatings used at Indian Point have a density on the order of 457 Ib/ft3. The surrogate's (ground silica) material specific gravity is 2.65, which corresponds to a microscopic density of 165 lb/ft3. The critical parameter for selecting the surrogate material is the volume of the material in the debris mix. The particulate material occupies a certain volume in the fibrous debris space that results in increasing resistance to flow and higher head loss. The surrogate material volume was adjusted to match the volume of the coatings particulate for coatings that are less dense than the silica (e.g. alkyds and epoxies). The volume of the silica material was adjusted to match the volume of the coatings material. The particle size for all coatings (epoxy, alkyd, and inorganic zinc) was simulated by 1 0-micron spheres; this is a conservative treatment of unqualified epoxy outside of the ZOI, which fails as 6-mil chips. The ground silica surrogate material is a spherical particulate ranging in size from just under 1 micron to approximately 100 microns.

EnterqV Response to Issue 3h.5:

As described in Section 3.4 of the GR, all qualified and unqualified coatings within the ZOI are assumed to fail. All unqualified and degraded (unacceptable) coatings outside the coating ZOI are assumed to fail. All design basis accident (DBA) qualified coatings that are not subjected to the break jet are assumed to remain intact in the post accident environment. Also, unqualified coatings that are under intact insulation are not considered to fail.

A ZOI of 4.28 for OBA-qualified/acceptable untopcoated inorganic zinc coatings and a ZOl of 4 for DBA-qualified/acceptable epoxy coating systems were used for the coating debris generation calculation. These destruction properties of the DBA-qualified/acceptable coating systems were obtained from testing performed by Westinghouse and documented in WCAP-1 6568-P (Reference 20).

Westinghouse evaluated the coating systems applied during construction and used for maintenance at the Indian Point units and concluded that they are similar in composition and applied in a manner that is consistent with the testing described in WCAP-1 6568-P. Therefore, the data reported in WCAP-1 6568-P is applicable to the DBA-qualif ied/acceptable coating systems used at Indian Point Units 2 and 3. A ZOI of 4.28 for DBA-qualified/acceptable untopcoated inorganic zinc coatings and a ZOI of 4 for DBA-qualified/acceptable epoxy coating systems was utilized.

A sensitivity review was conducted to address the possibility of a larger coatings quantity for untopcoated zinc due to a larger ZOI of 4.28D compared to 4.OD for epoxy. It was found that changing the ZOI from 4 to 4.28D increased the total area by less than 1%. Further review determined that the application density of the epoxy was significantly larger than the inorganic zinc.

NL-08-025 Page 74 of 125 Therefore, when considering both the application density and the respective ZOI, the epoxy system with a 4D ZOI is bounding.

Coating test samples were not irradiated; however, WCAP-1 6568-P references data supporting statements that irradiated coatings showed a slight strengthening and similar ductility to non-irradiated coatings.

Based on Section 3.4 of the GR, all qualified and unqualified coatings within the ZOI are assumed to fail as 1Oýtm spheres. Epoxy/epoxy phenolic unqualified coatings outside of the ZOI are assumed to fail as chips which may or may not transport. All other unqualified coatings outside of the ZOI are assumed to fail as 10Opm spheres.

Following the SER, the "thin bed" tests for Indian Point were conducted using 10Opm particulate coatings surrogate. The non-thin bed tests (with no clean screen) Were also conducted using the 10gm particulate coatings surrogate. This is considered conservative based the observation in previous Indian Point strainer array testing that the debris bridged across adjacent prototype Top-Hat strainer modules and filled nearly all of the interstitial volume. Therefore, it was assumed that coatings chips that reached the Indian Point sump could be completely absorbed within the fibrous debris and provide a negligible contribution to the sump strainer head losses. It is likely that chips surrounded by fibrous debris would orient parallel to the flow direction or load at the outer surface of the fiber and not affect the head loss. In contrast, small particles will likely fill the interstitial volume in a fibrous debris bed, lowering the porosity of the bed and creating a higher head loss.

Coatings walkdowns were performed to identify DBA qualified/acceptable, unqualified, and degraded coatings and to quantify the amount of debris that would be generated by them. Each coating area was estimated by breaking down the applied surfaces into simple geometric shapes with easily determined surface areas. The thickness of each coating was either recorded from station records or determined based upon previous experience. The maximum quantities of coatings debris are presented in the following tables.

Table 3h.5-1 Unit 2 Maximum Coating Debris Quantity - All breaks except the Reactor Cavity Break Coating Type Type Weight Analysis BekTp (Ibs)

Size (ptm)

BekTp Qualified Coatings Epoxy 6129, Epoxy 4129, Epoxy 4000, 590 0L

.(Inside ZOI)

Epoxy 6548/7107, Epox.y 5.0.0.0,.Epoxy D-1 590 0L Unqualified Coatings H"igh Temp. Aluminum, Epoxy/Efpoxy 29510L (inside ZOI)

Phenolic, Inorganic Zinc, Alkyd Enamel 2.1

.0L Unqualified Coatings Inorganic Zinc 191.60 10 LB,AB,SB (Outside ZOI)

Unqualified Coatings High Temp. Aluminum 8.25 10 AB,SB (Outside ZOO)

Unqualified Coatings Alkyd Enamel 32.29 10 LB,AB,SB

.(Outsidle ZOI)

Unqualified Coatings Epoxy/Epoxy Phenolic 423.12 153

• AB,SB

( O t s d Z O...............

I )......

Unqualified Coatings White RTV Caulk /

1189 0

LBS (Outside ZOI)

Black Polysilicone Caulk 189 0

LBS

• Chip or flake thickness (6 mils = 153 pm)

Additional 100 ft2 of Qualified Coatings associated with Outage 2R1 7 outside of the ZOl and thus considered not fail.

Additional 30 ft 2 of Unqualified Coatings associated with Outage 2R1 7 considered negligible.

L N L-08-025 Page 75 of 125 Table 3h.5-2 Unit 3 Maximum Unt3Mxiu~ain ers att

-AlbeasecptteRaco ait ra Coating Type Type Weight Analysis Break Type (Ibs)

Size (tI.m)

Qualified Coatings 195 Surfacer, Carboline 890, Epoxy 504.72 10 L

(inside ZOI) 6548/71 07, Epoxy E-1-7475 L

Unqualified Coatings High Temp. Aluminum, Epoxy/Epoxy 29.87 10 LB (Inside ZOI)

Phenolic, Alkyd Enamel Unqualified Coatings High Temp. Aluminum 8.25 10 AB,SB (Outside ZOI)

Unqualified CoatingsEpx/pxPhnic8.215*

ABS (Outside ZOI)Epx/pxPhnlc88215 BS Unqualified Coatings Alkyd Enamel 29.60 10 LB,AB,SB (Outside ZOI)

• Chip or flake thickness (6 mils = 153 Itm)

Enterciv Response to Issue 3h.6:

All coatings inside the ZOI will have a 10 micron particle coating debris size, per SER recommendation. Epoxy / Epoxy Phenolic unqualified coatings outside of the ZOI are assumed to fail as chips which may or may not transport. As demonstrated by testing described and confirmed in the Indian Point specific coatings evaluation, the size of chips or flakes is assumed to be equivalent to the smallest applied coating thickness, which corresponds to 6 mil (1153 pm). All other unqualified coatings outside of the Coatings ZOI are assumed to fail as 10 pm particles.

Enterov Resoonse to Issue 3h.7:

Several enhancements to the existing Entergy Nuclear Northeast fleet procedure, ENN-DC-1 50, Condition Monitoring of Maintenance Rule Structures, have been identified. These enhancements, captured in PMCRs, include a detailed checklist to the attachments for coatings and require a PM to visually inspect coating in the, Indian Point Unit 2 and 3 Vapor Containment Buildings during all future refueling outages. The inspection will be captured as part of the Structural Maintenance Rule. The frequency of the inspection will be every two (2) years or every cycle during the refueling outage. The process will require any degraded coatings be evaluated as acceptable or repaired prior to exiting the outage.

All coating requests in the VC are evaluated by the coating engineer and only approved DBA qualified coatings are used. The quantity of the coating will be added or deleted accordingly from the GIL 2004-02 coating debris generation calculations.

USNRC Issue 3i:

i. Debris Source Term The objective of the debris source term section is to identify any significant design and operational measures taken to control or reduce the plant debris source term to prevent potential adverse effects on the ECCS and CSS recirculation functions.

N L-08-025 Page 76 of 125 Provide the in formation requested in GL 04-02 Requested In formation Item 2.(f) regarding programmatic controls taken to limit debris sources in. containment.

GL 2004-02 Requested Information Item 2(f)

A description of the existing or planned programmatic controls that will ensure that potential sources of debris introduced into containment (e.g., insulations, signs, coatings, and foreign materials) will be assessed for potential adverse effects on the ECCS and CSS recirculation functions. Addressees may reference their responses to GL 98-04, A Potential for Degradation of the Emergency Core Cooling System and the Containment Spray System after a Loss-of-Coolant Accident Because of Construction and Protective Coating Deficiencies and Foreign Material in Containment," to the extent that their responses address these specific foreign material control issues.

In responding to GL 2004 Requested Information Item 2(f), provide the following:

1. A summary of the containment housekeeping programmatic controls in place to control or reduce the latent debris burden. Specifically for RMI/low-fiber plants, provide a description of programmatic controls to maintain the latent debris fiber source term into the future to ensure assumptions and conclusions regarding inability to form a thin bed of fibrous debris remain valid.

2. A summary of the foreign material exclusion programmatic controls in place to control the introduction of foreign material into the containment.

3. A description of how permanent plant changes inside containment are programmatically controlled so as to not change the analytical assumptions and numerical inputs of the licensee analyses supporting the conclusion that the reactor plant remains in compliance with 10 CFR 50.46 and related regulatory requirements.

4. A description of how maintenance activities including associated temporary changes are assessed and managed in accordance with the Maintenance Rule, 10 CFR 50.65.

If any of the following suggested design and operational refinements given in the guidance report (guidan ce report, Section 5) and SE (SE, Section 5. 1) were used, summarize the application of the refinements.

5. Recent or planned insulation change-outs in the containment which will reduce the debris burden at the sump strainers

6. Any actions taken to modify existing insulation (e.g., jacketing or banding) to reduce the debris burden at the sump strainers

7. Modifications to equipment or systems conducted to reduce the debris burden at the sump strainers

8. Actions taken to modify or improve the containment coatings program Enterqy Response to Issue 3i.1:

In general, it is plant policy to leave an area better than when you first entered it. Existing plant procedures support this concept in practice. Besides maintenance/construction following good housekeeping practices, the Radiation Protection group has a keen interest in ensuring good housekeeping is enforced to help reduce the spread of contamination and general area dose reductions.

Plant procedure OAP-007, 'Containment Entry and Egress" is applicable to both units. This

.procedure requires various inspections before exiting outage. It was revised to include specific Engineering inspections of the sump strainers and assemblies, as well as critical features of the

N L-08-025 Page 77 of 125 sump design like the flow barriers to ensure proper configuration. This procedure is already sensitive to Foreign Material Exclusion (FME) issue. A required Pre-job brief includes covering FME. The VC closeout checklist includes a detailed listing of unacceptable items such as:

combustible materials, debris,, non secured plastic bags/film/sheets, shoe covers, paper, fibrous materials, rags, wood, tape/rope, damaged insulation, non-metal signage. At the end of each outage, available personnel will perform numerous walk throughs to catch-and remove any extraneous materials. See also the next item.

See also the dust and latent debris control response described in 3i.3.

Entergy Response to-Issue 3i.2:

Ente~rgy Fleet procedure EN-MA-i 18, "Foreign Material Exclusion" is applicable to both units. It establishes specific requirements for physical controls to prevent foreign material from entering systems and components. This procedure is applicable whenever maintenance, modifications, repairs, inspections, and operating activities are performed.

Additionally, a procedure revision is in process that will identify the recirculation and containment sumps as-FME Level 1 areas, the highest level of cleanliness control. In the meantime, both sumps will be treated as such.

Procedure IP-SMM-RW-1 03; "Radioactive Waste Volume reduction Program" is applicable to both Units. While the purpose is reduction of radioactive waste, this procedure has several points which support Containment cleanliness. The procedure requires that non-essential materials (e.g.

packaging) not be brought into Containment, only the amount of consumnables require be taken in, and in general to minimize material brought into Containment.

Procedure IP'SMM-HU-102; "Pre-Job Briefing and Post Job Critiques" are'performed to refresh workers of important aspects of the job about to be worked. This procedure contains a standard checklist in which FME. and Housekeeping are discussed.

Additionally, inspections in the Containment building for reasons other than GL 2004-02 related provide an opportunity to capture potential adverse, conditions. Procedure 2-PT-Q092 for Unit 2, and 3-PT-0137 for Unit 3; both entitled "Containment Building Inspection" direct the personnel performing the inspections to identify any suspect FME concerns to Operations for disposition.

These procedures are performed quarterly, thereby providing an opportunity to observe conditions in-between refueling outages.

Enteray Response to Issue 3i.3:

To maintain the, required configuration of the containment recirculation function that supports the inputs and assumptions utilized to perform the mechanistic evaluation of this function, Indian Point has implemented programmatic and process controls as described below.

Plant procedures, programs, and design req uirements were reviewed to determine those that could impact the analyzed containment or recirculation function configuration. These reviews resulted in the identification of those documents that required revision or development of new documents to ensure continued compliance with the regulatory requirements of GL 2004-02 as~follows:

NL-08-025 Page 78 of 125

• Electrical Control Engineering Standard ENN-EE-S-010O-1P2 (Unit 2), Electrical Separation Design Criteria was revised and specifically:

o Phases out the use of vinyl cable tray tags. When, and as required, such tags will be replaced by DBA qualified tags.

o Excludes the use of new marinate and/or transite used for cable tray separation barriers.

o Eliminates use of new cable wrap for separation.

o Requires Engineering evaluation should a deviation be necessary.

• Engineering Standard ENN-EE-S-008-I P, 'Electrical Cable Installation Standard" is applicable to both units and was revised to eliminate unqualified material such as vinyl tags, tape, and blankets in new installations. An Engineering evaluation would be required should a deviation be necessary.

• Design Control Fleet design procedure EN-DC-i 15, "Engineering Change Development" is applicable to both units. This procedure screens changes for impact on GIL 2004-02 compliance..

Examples of specific screen items include any changes to: insulation, coatings, aluminum, and other metallic/non E metallic debris sources.

Fleet design procedure EN-DC-141, "Design Inputs" is applicable to both units. This procedure also contains numerous screening items to consider when developing designs.

Fleet design procedure EN-DC-313 "Procurement Engineering Process" requires revision to clearly identify GIL 2004-02 design considerations. This item is in process and being tracked by the corrective action system.

• Aluminum Control Use of Aluminum is typically restricted in PWR containments due to potential for post accident Hydrogen production and GSI concerns reinforce its restriction. TS-MS-007, "Specification for Piping and Equipment Insulation" already prohibits use of Aluminum jacketing or foil layers for insulation.

Plant procedure OAP-007, "Containment Entry and Egress" is applicable to both units and requires the removal of any aluminum brought into Containment that has not been evaluated by Engineering.

• Coatings Control See Response to 3h1.7.

• Insulation Control Plant procedure 0-SYS-404-GEN, "Installation of Insulating Materials for All Plant Piping and Equipment' is applicable to both units. It was created to maintain thermal insulation-configuration control. The procedure works with the new INSUL series of plant drawings, which were created for each unit from plant walk downs of the piping systems in Containment, and document the current analyzed insulation. The procedure requires

NL-08-025 Page 79 of 125 evaluation for the installation of any new insulation, or replacement that is not identical to the existin g material.

Tagging Control Plant procedure OAP-044, "Plant Labeling Program", is applicable to both units. This procedure was revised to. indicate that labels/tagging to be installed in the Containment Building shall be stainless steel and affixed in a suitable manner to assure it remain in place, e.g. cable or chain.

Containment Entry Control Refer to item 3Ji.1 & 3W.2.

" Maintenance FMVE Control Refer to item 3Ji.1 & 3Ji.2.

Dust and Latent Debris Control In order to ensure Containment dust, dirt, and latent debris does not exceed the analyzed quantities evaluated; a sampling program will be set up. The program will use the same methodology employed for the original walkdown and is per NEI 04-07 methodology as amended by SER. Two PMCRs for sampling to be performed on a recurring basis are currently being processed. Current FMVE and Housekeeping programs, as well as Containment cleaning efforts by Maintenance, Radiation Protection and Operations just prior to startup are expected to keep the loads within the bounds of the analysis.

Entergy Response to Issue 3i.4:

Maintenance activities including tem porary changes are subject to the provisions of 10 CFR 50.65(a)(4) as well as the Technical Specifications. The Entergy fleet procedures provide guidance' on 50.59 review process, which provides details and guidance on maintenance activities and temporary alterations; the on-line work control process procedure, which establishes the administrative controls for performing on-line maintenance of systems, structures and components to enhance overall plant safety and reliability; and the temporary modification procedure, which establishes the overall requirements for such changes.

Entergy Response to Issue 3i.5:

There are no insulation changeouts currently planned for the Indian Point units.

Entergy Response to Issue 3i.6:

Refer to Item 3Ji.5 above Enterpy Response to-Issue 3i.7:

Refer to Section 3.J.2 for descriptions of other modifications performed relative to the GSI effort.

NL-08-025 Page 80 of 125 Enterpgy Response to Issue 3i.8:

See Response to 3h.7 USNRC Issue 3i.:

Screen Modification Package The objective of the screen modification package section is to provide a basic description of the sump screen modification.

1, Provide a description of the major features of the sump screen design modification.

2. Provide a list of any modifications, such as reroute of piping and other components, relocation of supports,, addition of whip restraints and missile shields, etc., necessitated by the sump strainer modifications.

Enterpgy Response to 30.:

The existing grating and fine screen in the IR and VC sumps were replaced with flow barriers and basket (Top-Hat) type strainer assemblies designed to accommodate the increased post-accident debris loads. In addition, an extension strainer assembly will be connected to the Unit 2 VC sump strainer assembly during the spring 2008 refueling outage. The new strainers are sized to limit the head loss across them to ensure positive NPSH margin for the IR and RHR pumps. The flow channeling barriers are designed to route the post-LOCA water into the reactor sump and then up through the incore instrumentation tunnel to the VC annulus through openings in the crane wall before entering the IR sump or the VC sump / extension. This flow path is credited so that a large quantity of the LOCA generated debris will settle in the reactor sump or elsewhere in the VC before reaching the IR or VC sump / extension strainers.

The Top-Hat type strainers are made of 14 gauge Type 304 stainless steel plate perforated with 3/32" diameter holes. These Top-Hat assemblies are configured as four concentric cylinders (arranged in a double set) attached at one end to a rectangular plate. Two wire mesh filter elements are inserted between each set of cylinders with a steel wool debris bypass eliminator situated in the center of the entire module. The strainers were mounted to a water box that channels flow to the IR pit or RHR pump suction piping. Structural steel and flow barriers were installed around the sumps as part of the flow channeling scheme. Perforated plate was placed on the floor of the RHR heat exchanger room above the IR sump enclosure, and also over the trenches leading to the IR sump, to prevent large particles from being washed down directly into the sump. The new strainers significantly increase the effective area of strainer in the IR sump

(-3156 ft2 for both Units) and VC sump (-412 ft2 for Unit 2 and -1058 ft2 for Unit 3). As noted above, a -770 ft2 extension will be added to the VC sump bringing the total strainer area to -1182 ft2.The new strainers will prevent particles greater than 3/32" in diameter (versus the 1/8" original design) from entering the IR Pump suction. The maximum water velocity through the sump remains less than one foot per second. In order to install the strainer assemblies certain equipment had to be relocated to alleviate interferences.

Physical changes were also implemented to ensure required flow channeling. These included the following:

Permanently removed grating at the entrance to the reactor sump and incore tunnel.

Permanently removed the vertical grating on the south side of the incore tunnel.

Modified the access ladder to the reactor sump.

N L-08-025 Page 81 of 125 Reduced th *e curb height on the south end of the incore tunnei to 1". Also reduced the curb height around the reactor sump.

Modified the reactor sump platfform.

" Installed the incore tunnel flow channeling barriers.

" Cut three flow channel openings in the crane wall (Unit 2).

" Cut flow channel openi 'ngs in the crane wall and through the VC sump labyrinth wall (Unit 3).

" Installed flow channeling barriers at appropriate crane wall penetrations (Unit 3).

Installed personnel gates at applicable IR sump, VC sump, and crane wall openings.

" Removed the perforated plate strainer on the fuel transfer canal drain and installed a debris trash rack.

In addition, during the Unit 2 spring 2008 refueling outage, flow channeling screens will be installed on the 3" drain lines and on the crane wall penetrations. Also, grating with perforated plate will be placed on a section of the VC sump trench inside the crane wall.

These changes are intended to reduce debris transport to the EGOS sumps by minimizing the flow velocities and turbulent energy of the recirculating fluid as it flows back to the sump(s). The low velocities and torturous path will maximize debris settlement and sedimentation. The reactor sump

/ incore tunnel offers an expansive area free from turbulence that produces the low velocities allowing fo 'r the settling out of small and large debris. Consequently, only fines and particulate matter are transportable to the EGOS sumps.

Ente ray Response to 34.2:

Indian Point Unit 2 Due to the potential interaction of accident-generated debris with a combination of certain materials in the VC, borated water, and existing pH buffer (Trisodium Phosphate (TSP)), the quantity and physical nature of that debris is ultimately affected. With respect to GSI-1 91, the accumulation of the modified debris at the sump strainers may be such that the head, loss across the strainers reduces pump NPSH margin to an unacceptable degree. It has been predicted through testing and chemical analysis that specific Unit 2 calcium silicate-bearing insulation debris may react negatively with the boric acid and TSP in the VC water to yield a greater head loss across the strainers. It is planned to replace the present TSP buffer with Sodium Tetraborate (NaTB). This pH buffer replacement will be performed in the spring 2008 refueling outage.

Indian Point Unit 3 The IR pumps were replaced during the spring 2007 refueling outage. The replacement pumps are double inlet suction and have significantly lower NPSH requirements. Due to the predicted increased sump screen debris load determined by GL 2004-02 related analyses, the head losses through the IR sump are also predicted to increase. Based on hydraulic and NPSH calculations, due to the increased debris loads the original pumps would not have been able to fulfill their safety functions. The replacement pumps will be demonstrated to have the capability to operate without cavitation at the required flow rates assuming maximum anticipated sump screen head losses.

It is planned to replace the present NaOH solution which is injected into the VC during CSS operation with solid NaTB maintained in specially designed baskets located in the VC. The existing NaOH storage tank will be functionally eliminated. This pH buffer replacement will be performed prior to June 30, 2008 subject to prior NRC approval of the associated licensing basis change.

NL-08-025 Page 82 of 125 USNRC Issue 3k:

Sump Structural Analysis The objective of the sump structural analysis section is to verify the structural adequacy of the sump strainer including seismic loads and loads due to differential pressure, missiles, and jet forces. Provide, the information requested in GL 2004-02 Requested Information Item 2(d)(vi).

GL 2004-02 Requested Information Item 2(d)(vii) Verification that the strength of the trash racks is adequate to protect the debris screens from missiles and other large debris. The submittal should also provide verification that the trash racks and sump screens are capable of withstanding the loads imposed by expanding jets, missiles, the accumulation of debris, and pressure differentials caused by post-LOCA blockage under flow conditions.

1. Summarize the design inputs, design codes, loads, and load combinations utilized for the sump strainer structural analysis.

2. Summarize the structural qualification results and design margins for the various components of the sump strainer structural assembly.

3. Summarize the evaluations performed for dynamic effects such as pipe whip, jet impingement, and missile impacts associated with high-energy line breaks (as applicable).

4. If a backflushing strategy is credited, provide a summary statement regarding the sump strainer structural analysis considering reverse flow.

Enterav Response to Issue 3k.1:

The strainer structural analyses comply with plant specific design criteria. Within these requirements, Manual for Steel Construction by American Institute for Steel Construction (AlSO) constitutes the primary design code.

The structural evaluations are performed utilizing finite element analysis, supplemented by hand calculations. The evaluations follow the requirements of the plant specific design requirements.

The strainer is designed for the following loads, and the stresses are maintained within the material yield under the most adverse loading conditions.

• Deadweight: The deadweight loading includes the self weight of the strainer components.

No credit is taken for buoyancy effects following post-LOCA submergence of the strainer structure.

• Seismic Loads: Seismic analysis of the strainer is performed using dynamic modal analysis.

Modal and directional responses are combined consistently with plant specific design specifications. Hydrodynamic mass (virtual mass) effects resulting from post-LOCA submergence of the strainer are included in the modal analysis. The strainer structure is designed using a seismic damping value of 0.'5 percent. The structures are considered "Bolted Steel structures", and a damping value of 7 percent for SSE can be used per Regulatory Guide 1.61. Consequently, use of lower damping value signifies considerable conservatism in the design.

• Differential Pressure Load: The strainer structure may be subjected to differential pressure loading during ECCS pump operation following a LOCA as a result of debris accumulation.

The design of the strainer structure includes a differential pressure loading applied to all external surfaces, including perforated surfaces. No reduction in differential pressure loading is credited for the perforations.

NL-08-025 Page 83 of 125 Thermal Effects: The strainer structure is designed to allow unrestrained thermal growth through use of sliding connections and slotted bolt holes. These thermal releases are included in the analysis model and are considered for all loads, including seismic loading.

The design provides adequate thermal releases to accommodate the full range of thermal expansion movements associated with the maximum design temperature based on post-LOCA containment environmental and pool temperatures. Effects of elevated post-LOCA temperatures on the allowable material stresses are also considered in the design of the strainer structure.

The flow channeling design includes reactor cavity/in-core tunnel exit flow barriers, VC sump flow barrier, and gates (two access opening to the Crane wall, and two access opening to the compartment where IR sump is located) act as flow barrier.

The flow barriers/gates are qualified by analysis. The evaluations are performed by hand calculations or utilizing computer analysis (GTSTRUDL), supplemented by hand calculations. The evaluations follow the requirements of the plant specific design requirements. The flow barriers/gates are designed for the following loads and the stresses are maintained within the material yield under the most adverse primary loading conditions.

Deadweight: The deadweight loading includes the self weight of the components. No credit is taken for buoyancy effects following post-LOCA submergence of the flow barriers/gates.

Seismic Loads:

• Unit 2: Seismic Loads: Seismic analysis of the flow barriers/gates is performed using static analysis with peak acceleration. The flow barriers/gates design uses a seismic damping value of up to 1 percent. The flow barriers/gates are considered "Bolted Steel structures" and a damping value of 7 percent for SSE can be used per Regulatory Guide 1.61. Consequently, use of lower damping value signifies considerable conservatism in the design.

• Unit 3: Seismic Loads: Seismic analysis of the flow barriers/gates is performed using static analysis with peak acceleration or dynamic modal analysis. Modal and directional responses are combined consistent with plant specific design specifications. The flow

• barriers/gates design uses a seismic damping value of 0.5 percent. The flow barriers/gates are considered "Bolted Steel structures" and a damping value of 7 percent for SSE can be used per Regulatory Guide 1.61. Consequently, use of lower damping value signifies considerable conservatism in the design.

Pressure Load: The flow barriers/gates that may be subjected to sub-compartment pressurization due to their location within the containment building are designed to withstand the expected differential pressure loading.

Thermal Effects: The flow barriers/gates are bolted structures which allow adequate thermal relief at the bolted connections under post-LOCA containment pool temperature. Effects of elevated post-LOCA temperatures on the material stress allowables are also considered in the design of the flow barriers/gates.

The flow barriers/gates analyses comply with plant specific design criteria. Within these requirements, Manual for Steel Construction by American Institute for Steel Construction (AISC) constitutes the primary design code.

NL-08-025 Page 84 of 125 Enteray Response to Issue 3k.2:

Structural qualifications for the sump strainers were performed in the following analyses:

• Analysis of Recirculation Sump Strainer Structure

• Analysis of VC Sump Strainer Structure

• Analysis of Sump Strainer Top-Hat Considering the design loads and stresses described above, all components of the sump strainers for both units were found to be within acceptable plant design criteria and are thus qualified structurally. These components are capable of structurally withstanding, where applicable, the required design deadweight loads, seismic loads (including the hydrodynamic mass effects),

differential pressure loads, and thermal effects at the design temperature of 300 0F.

Ente rgy Response to Issue 3k.3:

Evaluations of dynamic effects associated with high-energy line breaks for the IR and VC sumps are included below.

Internal Recirculation Sump Strainer:

The IR sump is located inside the crane wall and is' surrounded by the concrete that extends to the operating floor. Therefore, the high-energy lines outside of this barrier will not impact the IR Sump.

There are high-energy lines inside this barrier; however none of these line breaks require the post-LOCA recirculation operation of the ECOS system. Therefore, the internal recirculation sump does not need to be evaluated for jet impingement or pipe whipping force.

Vapor Containment Sump Strainer:

The VC sump strainer is located inside the crane wall. A number of high energy lines are located within the crane wall. The isolation points on these lines were reviewed. An isolation point (generally a closed valve) is the location on the high energy line beyond which a pipe break would not require ECCS system to operate in the recirculation mode. It was determined that the isolation points are located entirely within the crane wall and away form the VC sump. The portion of the Unit 2 strainer outside the crane wall is protected from damage by virtue of its location. Therefore, the vapor containment sump strainer, including the extension strainer does not need to be evaluated for jet impingement or piping whipping force.

Enterav Response to Issue 3k.4:

No backflushing strategy is credited for ECCS sump performance.

USNRC Issue 3!.

Upstream Effects The objective of the upstream effects assessment is to evaluate the flowpaths upstream of the containment sump for holdup of inventory, which could reduce flow to and possibly starve the sump. Therefore, provide a summary of the upstream effects evaluation including the information requested in GL 2004-02, "Requested Information, " Item 2(d)(iv) including the basis for concluding that the water inventory required to ensure adequate ECCS or CSS recirculation would not be held

NL-08-025 Page 85 of 125 up or diverted by debris blockage at choke-points in containment recirculation sump return flowpaths.

1. Summarize the evaluation of the flow paths from the postulated break locations and containment spray washdown to identify potential choke points in the flow field upstream of the sump.

2. Summarize measures taken to mitigate potential choke points.

3. Summarize the evaluation of water holdup at installed curbs and/or debris interceptors.

4. Describe how potential blockage of reactor cavity and refueling cavity drains was evaluated, including likelihood of blockage and amount of expected holdup.

Enterciv Response to Issue 31.11:

Indian Point evaluated water inventory available for the EGOS or CSS recirculation. The minimum post-LOCA containment water level considered the water transferred from the RWST to the containment, accumulation of water in various holdup volumes in containment, RCS shrinkage, and water held up in the containment atmosphere and in transit (also see section 3g).

In addition, Indian Point evaluated the transportability of various debris. The debris transport evaluations used Computational Fluid Dynamics (CED) to model the containment pool flow paths and velocities. A three-dimensional computer aided (CAD) model of the Indian Point containment building floors and in-core instrumentation tunnels were developed and used for input to the CED model. The lower containment at Indian Point is basically made up of two compartments-the area inside the crane wall (the steam generator compartments), and the area outside the crane wall (the annulus). The steam generator compartments are connected to the annulus by doors that have perforated plate flow barriers installed. These flow barriers are designed to allow flow to pass through until they are blocked by debris that would collect on the screens. This forces flow down, as intended, into the reactor cavity through the in-core instrumentation tunnel, where it can then flow to the annulus through a set of crane wall holes next to the VC sump. Given the size of the in-core instrumentation tunnel entrance and exit, this is not a significant concern for upstream blockage.

A potential upstream blockage point is th'e 4-inch refueling canal drain line. Any sprays falling directly in the refueling canal must flow through the refueling canal drain, which runs to the floor of lower containment. If this drain were to become clogged with debris, a large amount of water would be held up in the refueling canal. To preclude the drain from clogging with debris, a large trash rack has been designed for the refueling canal drain (approximately 3ft x 9ft x i1ft). The spacing between the trash rack grating bars is sized such that any small pieces of debris that pass through the trash rack would also readily pass through the 4-inch drain. Therefore, plugging of the canal drain is prevented by the trash rack. However, holdup above in the refueling canal may still be possible due to the hydraulic head needed to overcome the drain line frictional losses and as described in Responses to Issues 3g.8 and 3g.9.

The high energy blowdown following a double-ended guillotine pipe rupture would dislodge insulation and paint coatings in the vicinity of the break location. Blowdown is considered to be omnni-directional within lower containment. After pressurizing the lower containment compartments, the blowdown would primarily relieve upward past the steam generators and pumps to upper containment. Some of the pressure would also be relieved to the annulus through the openings in the crane wall.

NL-08-025 Page 86 of 125 Since the blowdown would relieve to all areas of the containment building, the fraction of blowdown fl~ow to various regions can be reasonably estimated using the relative volumes of containment.

Fine debris would be easily suspended and carried by the blowdown flow in the vicinity of the break. However in areas farther away from the break that are not directly affected by the blowdown, this debris would likely fall to the floor.

Based on the assumption that debris would be carried with the blowdown fl ow, and the flow split would be~proportional to the containment volumes, the transport fraction for the fine debris was computed to be 79% to upper containment.

Seventy-nine percent of the small piece debris would also be blown toward upper containment.

However, some of this debris would be trapped by structures and grating, and some would be trapped as the blowdown flow makes significant bends. The results of the DDTS testing showed that in a wetted, highly congested area, approximately 10% of small fiberglass debris would be trapped by miscellaneous structures, and approximately 25% would be trapped by grating. Also, 17% of small fiberglass debris was shown to be captured at 900 turns in a flow path. Although 90' turns might not have to be negotiated by debris blown to upper containment at Indian Point, significant bends would have to be made. Therefore, it was estimated that 5% of the small fiberglass debris blown upward would be trapped due to changes in flow direction. The openings in the operating deck at Indian Point are largely covered with grating, so the percentage of small fibrous debris that would be blown to upper containment is estimated to be 51 %, based upon calculations.

The BWR URG indicates that grating would trap approximately 65% of the small RMI debris blown toward it. This gives a calculated -blowdown transport fraction of small RMI debris to upper containment of 28% for Unit 2.

The large piece debris would be blown upward similar to the small piece debris. However, since this debris would not pass through the grating, the transport fraction to upper containment would be 0%. All large and small piece debris not blown into upper containment was conservatively assumed to fall or be washed back to the floor.

In conclusion, large debris is not expected to be blown upward to upper containment since it will not pass through the grating. Small and fine debris is capable of being blown upward into upper containment. Any debris capable of clogging the refueling canal drain will be caught up on the trash rack. Any debris capable of bypassing the trash rack should be sufficiently small to pass through the drain as well. Therefore, there is no concern with plugging of the refueling canal drain due to debris.

Enterav Response to Issue 31.2:

To mitigate potential choke points, flow barriers and walls were installed to direct flow through areas that are much larger than the largest estimated debris size. Hence, as the flow travels from the break location, through the in-core instrumentation tunnel and out the crane wall holes, all flow areas are significantly larger than any of the postulated debris sizes. Refer to Response to Issue 31.4 for a discussion of the refueling canal drain.

Entergy Response to Issue 31.3:

Once containment spray begins, a portion of the water will fall and be retained on the operating floor. This holdup is due to the hydraulic head of water required to push the containment spray

N L-08-025 Page 87 of 125 water off of the operating floor. Flow across the operating floor will be approximated by assuming weir flow over a weir opening of a length equal to the length of the openings through which water can flow off of the floor.

As much of the 68' elevation of the ann'ular region i s concrete slab, water will be retained. As was done for the operating deck, flow across the floor will be approximated by assuming weir flow over a weir opening of a length equal to the length of the openings through which water can flow off the floor.

To account for miscellaneous holdup volumes not specifically quantified in the water level calculation, a miscellaneous holdup quantity of 500 ft3 is included for the LBLOCA minimum safeguards case and SBLOCA with sprays cases. A volume of 250 ft3 is included for the end-of-event and SBILOCA - no sprays cases. Additional curbs were built and left in place to ensure that during normal operation (power and shutdown) any incidental leakage would be channeled to the desired section of the VC sump. These curbs are considered to have insignificant effects on water hold-up or flow patterns during the post-LOCA timeframe.

Entergy Response to Issue 31.4:

See response to 31.1 regarding the refueling cavity drain.

The reactor cavity is the lowest elevation in the containment and does not have a drain line. In general, the containment was designed to facilitate free drainage to the 46 foot elevation without choke points.

Potential hold-up above the refueling canal drain due to hydraulic head to overcome drain line frictional losses has been evaluated in the containment sump water level calculation.

USNRC Issue 3m:

Downstream effects - Components and Systems The objective of the downstream effects, components and systems section is to evaluate the effects of debris carried downstream of the containment sump screen on the function of the ECCS and CSS in terms of potential wear of components and blockage of flow streams.

Provide the information requested in GL 04-02, "Requested Information, " Item 2. (d)(v) and 2. (d)(vi) regarding blockage, plugging, and wear at restrictions and close tolerance locations in the ECCS and CSS downstream of the sump by explaining the basis for concluding that inadequate core or containment cooling would not result due to debris blockage at flow restrictions in the ECCS and CSS flowpaths downstream of the sump screen, (e.g., a HPSI throttle valve, pump bearings and seals, fuel assembly inlet debris screen, or containment spray nozzles). The discussion should consider the adequacy of the sump screen's mesh spacing and state the basis for concluding that adverse gaps or breaches are not present on the screen surface. For GL 2004-02, Item 2(d)(vi) provide verification that the close-tolerance subcomponents in pumps, valves and other ECCS and CSS components are not susceptible to plugging or excessive wear due to extended post-accident operation with debris-laden fluids.

GL 2004-02 Requested Information Item 2(d)(v The basis for concluding that inadequate core or containment cooling would not result due to debris blockage at flow restrictions in the ECCS and CSS flowpaths downstream of the sump screen, (e.g., a HPSI throttle valve, pump bearings and seals, fuel assembly inlet debris screen, or containment spray nozzles). The discussion should consider the adequacy of the sump screen's

NL-08-025 Page 88 of 125 mesh spacing and state the basis for concluding that adverse gaps or breaches are not present on the screen surface.

GL 2004-02 Requested In formation Item 2(d)(vi)

Verification that the close-tolerance subcomponents in pumps, valves and other ECCS and CSS components are not susceptible to plugging or excessive wear due to extended post-accident operation with debris-laden fluids.

1. If USNRC-approved methods were used (e.g., WCAP-16406-P with accompanying UISNRC SE) briefly summarize the application of the methods.

2. Provide a summary and conclusions of downstream evaluations.

3. Provide a summary of design or operational changes made as a result of downstream evaluations.

Enterciv Response to Issue 3m.2(d)(vi).11:

The following methodology was employed in the downstream effects evaluation.

1. The downstream effects evaluation takes into consideration the plant-specific containment sump filter effluent profiles and associated filter efficiency factor which were determined utilizing the results of prototype filter testing performed at Alion laboratories, with the effluent examined with SEM and optical microscopy to determine the outlet fiber sizing profile.

Strainer modules underwent full bypass testing which concluded that the strainer modules installed are not susceptible to an air core vortex. Therefore, there is not a concern with an air core vortex causing a portion of the strainer to maintain clear strainer area leading to additional fiber bypass.

Using the Debris Generation and Debris Transport Calculation results and the results of the strainer bypass testing, the maximum debris concentration was determined (Unit 2 = 813.6 ppm; Unit 3 = 803.9 ppm), and the individual mass fractions were calculated per the guidance contained within WCAP-1 6406-P, Revision 1 (Reference 21). An additional 60 pounds of unqualified coatings was added for Unit 2 and 370 pounds for Unit 3 to provide margin.

Further, the wear analyses for some components was performed under the conservative conditions of a constant, more concentrated debris profile (Unit 2 = 1143 ppm; Unit 3 =

1528 ppm) and provided wear results which were well below the acceptance criteria of less than 3 percent change in flow and/or area. Specific guidance on orifice wear evaluation to account for bell-mouthing on sharp edges was provided with the issuance of WCAP-1 6406-P, Revision 1, and was incorporated into this analysis.

2. The cold leg recirculation and hot leg recirculation alignments for the ECOS which includes IR, RHR, HHSI flow paths and portions of the OSS were reviewed to ensure that all of the flow paths and components impacted by the debris passing through the sump screens are considered. Further, return pathways to the sump such as pool drains, cavities, isolated containment compartments, and any constricted drainage paths, as well as the containment spray itself were also assessed for potential obstruction.

NL-08-025 Page 89 of 125

3. A detailed methodology was developed to evaluate whether the system valves, piping, instrument tubing and heat exchangers could be susceptible to blockage or wear from the debris that passes through the sump strainer:

a. Review the safety function of the containment heat removal systems and the emergency core cooling systems that use the recirculation and containment sump as the source for system cooling water.

b. Identify the systems required for supporting the safety functions-of the containment heat removal systems and the emergency core cooling syste ms.

c. Identify the flow paths for each system used during recirculation mode following a DBA.

d. Review flow diagrams, piping and instrumentation drawings (P&ID), vendor drawings, vendor manuals, and other available plant documentation to determine -the size of the flow passages in each component in the flow path. Determine the internal materials of construction for components of concern for wear and abrasion. Determine whether or not the component-is located within a stagnant branch line (i.e., an instrument line).

e. Compare the size of the flow passageways to the size of debris that could enter the process fluid through the sump screen openings. Conservatively, blockage evaluations were performed using a particle size of 0.14" (9/64"), larger than the screen hole size of 0.094" (3/32").

f. All downstream valves were screened according to Section 8.2.3 of WCAP-16406-P to identify those susceptible to wear. Then, all downstream components including identified valves were evaluated for wear according to WCAP 16406-P Sections 7 and 8.

Entergy Response to Issue 3m.2(d)(vi2:

With the following exceptions, all of the ECCS/SlS components have been shown to be able to accommodate 0. 14"' diameter particulate and f ibrous debris without blockage occurring and have acceptable cumulative wear and abrasion effects for a mission time of 30 days:

• The evaluation for blockage, wear and abrasion effects from the debris laden recirculation flow through the IR, RHR and HHSI pumps is not complete The debris loading assumed in the downstream effects evaluation includes an additional 60 pounds (Unit 2) and 370 pounds (Unit 3) of unqualified coatings to provide additional margin for possible unidentified debris loads. The tables below provide a summary of the components evaluated and the results of the wear evaluation-for a mission time of 30 days.

N L-08-025 Page 90 of 125 Table 3m2-1 Unit 2 Summary of Wear Evaluation for each ECS SCorn onent Component ID(s)

Type Acceptance?

HCV-638,640 Butterfly Valve Yes FE-6454,6456,6457,6458 Cage Valve Yes SI-743 Globe Valve Yes SI-1817A,B Globe Valve Yes SI-1870 Globe Valve Yes SI-856A Globe Valve Yes SI-856B Globe Valve Yes SI-856C Globe Valve Yes SI-856D Globe Valve Yes SI-856E Globe Valve Yes SI-856F Globe Valve Yes Cont. Spray Nozzles Nozzle Yes FE-642 Orifice Yes FE-924 Orifice Yes FE-924A Orifice Yes FE-925 Orifice Yes FE-926 Orifice Yes FE-926A Orifice Yes FE-927 Orifice Yes FE-945A,B Orifice Yes FE-946A,B,C,D Orifice.

Yes RHR Heat Exchanger Heat Exchanger Yes RHR Seal Water Heat Heat Exchanger Yes Exchanger SI Seal Water Heat Heat Exchanger Yes Exchanger

N L-08-025 Page 91 of 125 Table 3m2-2 Unit 3 Su mmar of Wear Evaluation for each ECOS/OSS Cornponent Component ID Type Acceptance?

SI-638,640 Butterfly Valve Yes SI-21 65 Cage Valve Yes SI-21 66 Cage Valve Yes SI-2168 Cage Valve Yes SI-2169 Cage Valve Yes SI-2170 Cage Valve Yes SI-21 71 Cage Valve Yes SI-2172 Cage Valve Yes AC-841 Globe Valve Yes AC-842 Globe Valve Yes AC-i1870 Globe Valve Yes SI-856G Globe Valve Yes SI-856H Globe Valve Yes SI-1803 Globe Valve Yes SI-1877A,B Globe Valve Yes BIT INLET NOZZLES Nozzle Yes CONTAINMENT Nzl e

SPRAY NOZZLES Nzl e

FE-642 Orifice Yes FE-945A,B Orifice Yes FE-946A Orifice Yes FE-946B Orifice Yes FE-946C Orifice Yes FE-946D Orifice Yes FE-984,985 Orifice Yes FE-OrfcYe 924A,925,926A,927 OrfcYe FE-924B Orifice Yes FE-926,980,981,982 Orifice Yes FE-983 Orifice Yes SIPFE 31,32,33 Orifice Yes RHR Heat Exchanger Heat Yes Exchanger RHIR Seal Water HeatYe Heat Exchanger Exchanger Ye SI Seal Water Heat HeatYe Exchanger Exchanger Ye Entergy Response to Issue 3m.2(d)(vi).3:

No design or operational changes were performed as a result of the debris blockage or wear evaluations of downstream components excluding pumps. Any necessary changes to pumps will be identified through the course of the continuing pump evaluations.

NL-08-025 Page 92 of 125 USNRC Issues 3.n Downstream Effects - Fuel and Vessel 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.

1. Show that the in-vessel effects evaluation is consistent with, or bounded by, the industry generic guidance (WCAP-16793), as modified by USNRC comments on that document.

Provide a basis for any exceptions.

Enterpy Response to Issue 3n.1 Westinghouse has performed evaluations for Indian Point Nuclear Power Plant of the downstream impact of sump debris on the reactor vessel and nuclear fuel following a loss of coolant accident (LOCA). The downstream effects evaluations were performed in accordance with the methodology presented in WCAP-1 6406-P. The evaluations consider the effect of debris ingested through the containment sump screen on the following components deemed to be required to operate:

Reactor vessel internals Nuclear fuel It was found that all dimensions of the essential flow paths through the reactor internals are adequate to preclude plugging by sump debris. The smallest flow clearances found in the reactor vessel internals evaluations are 0.46 inches, which is almost twice the maximum debris dimension (0.25 in) for either dleformable or non-deformable debris with a sump screen hole size of 0. 125 inches. Note that the installed Indian Point screen hole size is 0.09375 inches making the evaluation, which retained the use of the larger assumed size of 0. 125 inches, conservative.

In the event of a HELB, a small amount of the fibrous debris generated and transported to the sump will be ingested into the ECOS and 055 flow paths and carried through the RCS, possibly affecting downstream components. A portion of this fibrous debris in the ECOS flow path may collect on the underside of the fuel bottom nozzle.

Once a fiber bed of approximately 1/8th inch thickness is formed, and if there is also particulate debris in the recirculating flow, a thin bed may occur.

For the evaluation of the cold-leg break, although there is a high rate of bypass flow around the core, the fiber bed builds to approximately 0.09 inch thickness for Unit 2 and to approximately 0.08 inch thickness for Unit 3 in 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br />.

,For the evaluation of the hot-leg break, the thickness of the fibrous bed forming on the bottom of the core is calculated to reach a 0.125-inch thickness within minutes, regardless of the sensitivity case.

For hot-leg recirculation following a cold-leg or hot-leg break, the fiber concentration is depleted enough that essentially no fiber deposits on the top nozzle.

The acceptance criteria defined in the calculation states that core cooling is maintained if a fiber bed of <11/8 inch is formed at the core inlet. For Indian Point, a fiber volume of < 1 ft3 at the core

.inlet will result in a continuous fiber bed of <11/8 inch. To determine a sump screen capture

NL-08-025 Page 93 of 125 efficiency that will prevent the core inlet acceptance criteria from being exceeded, a slight simplification of the model used in the calculation can be employed. The model assumes a 95%

fiber capture efficiency at the fuel and assumes the remaining 5% returns to the sump. A conservative simplification would assume 100% capture efficiency at the fuel.

Employing this simplification for Indian Point, a conservative screen capture efficiency can be calculated. Indian Point Unit 2, with a total fiber load of 213.1 ft3 and assuming 100% capture efficiency at the core inlet, a sump screen efficiency of >99.531 % is required to prevent 1 ft3 from depositing at the core inlet. Indian Point Unit 3, with a total fiber load of 237.8 _ft3 and assuming 100% capture efficiency at the core inlet, a sump screen efficiency of >99.580% is required to prevent 1 ft3 from depositing at the core inlet.

(1 - 1/213. 1) xl100=99.531 %

(1 - 1/237.8) x 100 = 99.580%

Also note that, the potential for particulate debris, in and of itself, to impede flow into and through the core has been generically considered. Based on the guidance in the GR, the deposition of particulates of sufficient size and number on fuel elements such that particulate debris, by itself, will impede flow through the fuel is unlikely.

The quantity of fiber passing through the Debris Bypass Eliminator within the new Top-Hat modules for Indian Point was conservatively determined in the Summary Bypass Report. The total quantity of fiber that could bypass through the Debris Bypass Eliminator and collect at the top or bottom of the nuclear reactor core is 0. 188 ft3. This is not sufficient to~develop a "thin bed" debris bed thickness of 1/8". Since the total quantity of fiber is not sufficient to develop a 1/8" thick debris bed, the quantity of fiber is not expected to provide the required structure to bridge over the passageways at the bottom and top of the nuclear fuel assemblies. In addition, the prototype test strainer outlet samples showed that the average outlet fiber particle size was 290 microns, an actual size measurement which is far smaller than the associated WOAP-based projections.

Therefore, blockage of the post-LOCA flow through the nuclear fuel assemblies is not expected.

USNRC Issues 3.o Chemical Effects The objective of the chemical effects section is to evaluate the effect that chemical precipitates have on head loss and core cooling.

1. Provide a summary of evaluation results that show that chemical precipitates formed in the post-LOCA containment environment, either by themselves or combined with debris, do not deposit at the sump screen to the extent that an unacceptable head loss results, or deposit downstream of the sump screen to the extent that long-term core cooling is unacceptably impeded.

2. Content guidance for chemical effects is provided in Enclosure 3 to a letter from the NRC to NEI dated September 27, 2007 (ADAMS Accession No. ML0726007425).

2.1 Sufficient 'Clean' Strainer Area

i.

Those licensees performing a simplified chemical effects analysis should justify the use of this simplified approach by providing the amount of.

debris determined to reach the strainer, the amount of bare strainer area and how it was determined, and any additional information that is needed to show why a more detailed chemical effects analysis is not needed.

2.2 Debris Bed Formation.

NL-08-025 Page 94 of 125

i.

Licensees should discuss why the debris from the break location selected for plant-specific head loss testing with chemical precipitate yields the maximum head loss. For example, plant X has break location 1 that would produce maximum head loss without consideration of chemical effects. However, break location 2, with chemical effects considered, produces greater head loss than break location 1. Therefore, the debris for head loss testing with chemical effects was based on break location 2.

2.3 Plant Specific Materials and Buffers

i.

Licensees should provide their assumptions (and basis for the assumptions) used to determine chemical effects loading: pH range, temperature profile, duration of containment spray, and materials expected to contribute to chemical effects.

2.4 Approach to Determine Chemical Source Term (Decision Point)

i.

Licensees should identify the vendor who performed plant-specific chemical effects testing.

2.5 Separate Effects Decision (Decision Point)

i.

State which method of addressing plant-specific chemical effects is used.

2.6 AECL Model

i.

Since the NRC USNRC is not currently aware of the testing approach, the NRC USNRC expects licensees using it to provide a detailed discussion of the chemical effects evaluation process along with head loss test results.

ii. Licensees should provide the chemical identities and amounts of predicted plant-specific precipitates.

2.7 WCAP Base Model

i.

For licensees proceeding from block 7 to diamond 10 in the Figure 1 flow chart fin Enclosure 3 to a letter from the NRC to NEI dated September 27, 2007 (ADAMS Accession No. ML0726007425)], justify any deviations from the WCAP base model spreadsheet (i.e., any plant specific refinements) and describe how any exceptions to the base model spreadsheet affected the amount of chemical precipitate predicted.

ii. List the type (e.g., AIOOH) and amount of predicted plant-specific precipitates.

2.8 WCAP Refinements: State whether refinements to WCAP-16530-NP were utilized in the chemical effects analysis.

2.9 Solubility of Phosphates, Silicates and Al Alloys

i.

Licensees should clearly identify any refinements (plant-specific inputs) to the base WCAP-16530 model and justify why the plant-specific refinement is valid.

ii. For crediting inhibition of aluminum that is not submerged, licensees should provide the substantiation for the following: (1) the threshold concentration of silica or phosphate needed to passivate aluminum, (2) the time needed to reach a phosphate or silicate level in the pool that would result in aluminum passivation, and (3) the amount of containment spray time (following the achieved threshold of chemicals) before aluminum that is sprayed is assumed to be passiva ted.

iii. For any attempts to credit solubility (including performing integrated testing), licensees should provide the technical basis that supports extrapolating solubility test data to plant-specific conditions. In addition, licensees should indicate why the overall chemical effects evaluation

N L-08-025 Page 95 of 125 remains conservative when crediting solubility given that small amount of chemical precipitate can produce significant increases in head loss.

iv. Licensees should list the type (e.g., AIOOH) and amount of predicted plant specific precipitates.

2. 10 Precipitate Generation (Decision Point)

i.

State whether precipitates are formed by chemical injection into a flowing test loop or whether the precipitates are formed in a separate mixing tank.

2.11 Chemical Injection into the Loop

i.

Licensees should pro vide the one-hour setted volume (e.g., 80 ml of 100 ml solution remained cloudy) for precipitate prepared with the same sequence as with the plant-specific, in-situ chemical injection.

ii. For plant-specific testing, the licensee should provide the amount of injected chemicals (e.g., aluminum), the percentage that precipitates, and the percentage that remains dissolved during testing.

iii. Licensees should indicate the amount of precipitate that was added to the test for the head loss of record (i.e., 100 percent 140 percent).

2.12 Pre-Mix in Tank

i.

Licensees should discuss any exceptions taken to the procedure recommended for surrogate precipitate formation in WCAP-16530.

2.13 Technical Approach to Debris Transport (Decision Point)

i.

State whether near-field settlement is credited or not.

2.14 Integrated Head Loss Test with Near-Field Settlement Credit

i.

Licensees should provide the one-hour or two-hour precipitate settlement values measured within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of head loss testing.

ii. Licensees should provide a best estimate of the amount of surrogate chemical debris that settles away from the strainer during the test.

2.15 Head Loss Testing Without Near Field Settlement Credit

i.

Licensees should provide an estimate of the amount of debris and precipitate that remains on the tank/flume floor at the conclusion of the test and justify why the settlement is acceptable.

ii. Licensees should provide the one-hour or two-hour precipitate settlement values measured and the timing of the measurement relative to the start of head loss testing (e.g., within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />).

2.16 Test Termination Criteria

i.

Provide the test termination criteria.

2.17 Data Analysis:

i.

Licensees should provide a copy of the pressure drop curve(s) as a function of time for the testing of record.

ii. Licensees should explain any extrapolation methods used for data analysis.

2.18 Integral Generation (A lion) 2.19 Tank Scaling /Bed Formation

i.

Explain how scaling factors for the test facilities are representative or conservative relative to plant-specific values.

ii. Explain how bed formation is representative of that expected for the size of materials and debris that is formed in the plant specific evaluation.

2.20 Tank Transport

i.

Explain how the transport of chemicals and debris in the testing facility is representative or conservative with regard to the expected flow and transport in the plant-specific conditions.

NL-08-025

-Attachment 1

Page 96 of 125 2.21 30-Day Integrated Head Loss Test

i.

Licensees should provide the plant-specific test conditions and the basis for why these test conditions and test results provide for a conservative chemical effects evaluation.

ii. Licensees should provide a copy of the pressure drop curve(s) as a function of time for the testing of record.

2.22 Data Analysis Bump Up Factor

i.

Licensees should provide the details and the technical basis that show why the bump-up factor from the particular debris bed in the test is appropriate for application to other debris beds.

Entergv Response to Issue 3o.1 In response to GL 2004-02, Entergy has performed an evaluation assessing the impact that chemical effects may have on the debris head loss predicted on the ECCS recirculation sump screen. These chemical effects result from, interactions between the sump coolant and the materials within containment and the debris located on sump screen.

ALION Science & Technology performed the chemical effects'evaluation associated with the Unit 2 and Unit 3 plant specific environment and, assessed the impact on debris head *loss to support the resolution of GL 2004-02. The investigation began with the review of the ICET Test#5 (the ICET test that corresponds to the Indian Point conditions), progressed to the WCAP-1 6530 evaluation, reviewed the resulting predicted precipitate against plant specific benchtop tests in an integrated environment and then performed small scale combined integrated chemical effects head loss experiment over 30 days. The 30 day integrated chemical effects debris head loss experiment was performed at the VUEZ test facility.

The results of the chemical effects evaluation has concluded that the impact of chemical effects does affect head loss over time and is a strong function of the pH, aluminum corrosion and to a lesser extent interactions with buffer. Units 2 and 3 are planning to implement a buffer change to replace the TSP/NaOH buffer with NaTB to minimize or mitigate the chemical effects on debris head loss and sump performance. At this time, NaTB has been shown to be an ideal buffer relative to others by producing minimal chemical effects during the entire temperature range of the mission time. ICET#5 and NUREG/CR-6913 have also confirmed minimal chemical effects with NaTB buffer.

The chemical effects evaluation consisted of the following steps:

Step 1:

Obtain and develop plant specific inputs Step 2:

Perform WCAP-1 6530 evaluations Step 3:

Perform integrated plant specific bench top experiments with debris and NaTB Step 4:

Compare Task 1 and 2 with ICET results Step 5:

Perform 30 Day integrated chemical effects head loss experiments representing representative debris load quantities.

Step 6:

Compare and contrast results from all testing programs Step 7 Develop chemical effects increase (bump-up) factor to apply to prototype screen debris head loss testing The results of the evaluation are summarized in the following sections.

In general, the impact of chemical effects on head loss occurs due to

NL-08-025 Page 97 of 125

1) the corrosion/l each in g of materials in containment when subject to the pH, temperature and coolant chemistry;

2) the subsequent potential re-association of elements in solution to form new compounds and precipitates dependent on the time, pH, temperature and solubility in the coolant; and

3) the impact of these precipitates on debris head loss over time.

To provide a technical basis for determining the impact of chemical effects on debris head loss, an integrated approach was implemented addressing all three phenomena. The integrated approach included the performance of a 30-day debris head loss experiment within a simulated containment environment. This 30-day debris head loss experiment was similar to the ICET program but included a sump screen with the plant specific debris load to monitor head loss increases over the 30 day mission time.

30 Day Chemical Effects Head Loss Testing The tests were conducted in a vessel with representative structural materials, insulation and debris samples included in the simulated containment environment, their quantities scaled to preserve the plant specific conditions. Representative debris samples were placed in the vessel in a chemically non-reactive container that allowed water to flow in the region of the samples while confining the material. Test conditions, i.e., material quantities and containment environment were designed to be within range of conditions considered for the integrated plant analysis, with specific parameters chosen to be conservative from a chemical effects perspective.

The test tank had appropriate temperature control such that temperatures of the simulated sump fluid followed the time-temperature profile that matched the plant estimated temperature profile to within +/-5 'F.

The initial make-up of the solution within the tank replicated that which is assumed to occur at the start of a post-LOCA event. Buffer was added to the test tank at an appropriate conservative rate and as it is expected to be introduced into the containment environment. Once the scaled amount of buffer was added, no further pH adjustment was made. Based on bench-top experiments and ICET results, pH doe~s not change appreciably throughout the 30 day experiment.

Within the test tank was a screen that was loaded with. appropriately scaled quantities of the plant specific debris mixture. The coolant was circulated through the debris bed at the same approach velocity as the new strainer approach velocity. Head loss measurements across the debris bed were recorded continuously for the duration of the experiment.

The test was designed to replicate the amount and rate of release of those elemental materials within containment that are potentially responsible for the formation of precipitates. Small samples of fluid were taken at regular intervals and analyzed for various metals (Al, Ca, Cu, Fe, B, Ni, Na, Si, and Zn) by AES ICP spectroscopy.

• The definition of the four (4) chemical effects experiments or loops was based on conservative loads associated with each of the VC/IR sumps in each of the Units. This is discussed in more detail in response to 3o.2.2(i).

The bed thickness established in each chemical loop was based on the fiber loading calculated to

/reach the sump screen. The equivalent bed thickness (volume of fiber/screen area) is presented in

N L-08-025 Page 98 of 125 Table 3.o.1-1 for each of the loops. Based on the prototype testing and replacement screen design, the bed thicknesses tested below do not bridge the gaps in the top-hat screen.

Table 3.o.1-1: Experimental Fiber Bed Thickness Loop No.

Bed thickness (in) 1 0.63" 2

0.92" 3

0.74" 4

0.36" The debris beds were formed by the VUEZ technicians to ensure a homogenous and uniform bed.

Figure 3.o.1 -1 illustrates the uniformity of the debris beds for each of the loops. The consistency of the formed debris bed is identical to that of the prototype replacement screen head loss testing performed by ALIGN.

Sump Chemistry The post-LOCA chemical byproducts from radiolysis and RCS internals are hydrochloric acid (HCI),

nitric acid (HNOA) and lithium (Li). In addition to these post-LOCA byproducts, boron is present in the recirculation water. The boron concentration is 2,570 ppm for Unit 2 and 2,408 ppm for Unit 3.

Based on this boron concentration, the lower bound pH is near 4.5 to 4.8 prior to the buffer addition. Entergy plans to utilize sodium tetraborate as the buffer agent which results in a sump pH of approximately 7.5 after buffer addition.

WCAP-1 6530 Evaluation The WCAP-16530 evaluations considering the plant specific materials and replacement buffer, NaTB, were performed. The four (4) cases correspond to the 30 day experiments performed at VUEZ. These precipitate loads are quite low based on the Unit 2 and 3 replacement screen areas and illustrate the benefits associated with the NaTB buffer change.

NL-08-025 Page 99 of 125 Results of 30 day Testing The results of the 30 day testing did not yield any significant precipitate formation or head loss increases as expected. The SEM micrographs (Figure 3.0.1-2) identify a slight film substance on the surface of the fibers which are under original conditions smooth glass rods. The SEM also illustrates the change to the surface roughness of the fibers which would increase the head loss through the debris bed.

N L-08-025 Page 100 of 125 Images of 30 Day Debris Bed Comparison of Testing Programs The following Figure 3.o.1-3 compares the concentrations of aluminum, silicon and calcium for the VUEZ and ICET#5 experiments along with the WCAP predictions. It should be noted that the ICET#5 pH was 8.3 and the VUEZ pH was 7.5 and the WCAP predictions were determined based on a pH of 7.5. The higher ICET pH will have a pronounced affect on the corrosion of aluminum as illustrated in the following figures. It should also be noted that the ICET#5 experiment contained about 8x the amount of aluminum as Indian PointNVUEZ 30 day testing.

The VUEZ aluminum concentration exceeds the WCAP predictions for all tests. However, the VUEZ aluminum concentration is significantly less than the ICET#5 results for the reasons cited above and acceptable because it accurately approximates the Unit 2 and 3 condition.

NL-08-025 Page 101 of 125 The VUEZ and ICET#5 calcium and silica concentrations closely match the VUEZ experiment providing consistently slightly higher concentrations than what is expected at Unit 2 and 3. WCAP-16530-NP significantly over predicts the dissolution of silicon as compared to the VUEZ and ICET experiments. This illustrates the conservative value of sodium aluminum silicate in the WCAP-16530-NP. Therefore the use of the VUEZ test results is appropriate in these evaluations.

The comparison of concentrations of metals is provided on the following pages.

N L-08-025 Page 102 of 125 CaselI Case 2 Case I Ai Release Case2 Al Rolease so05 404 E-as 1~s 2CA VrAl) 20 20CseVm (Al) 2 30(A E

KA75 A 10 10 01 0,0 1000 2000O 3000 4000 0000 6000 7000 8O00 Time (hr) 0,0 1000 2000 3000 4000 0000 600,0 7000O 800.0 Time (hr)

Case I Co Release Case 2 Ca Release 40 30

-C21 WA(a 20 aVe(

0,0 1000 2000 300,0 4000 50000 6000 7000O 800 Time (h,)

I U

S U

0.0 1600.

200.0 300.0 400.0 500.0 600.0 700.0 800.0 Time (hr)

Case I Si Rolease Cass 2 3i Releas" so 70 360 200 10 10 I-I I

0I 0.0 100.0 200.0 300.0 400.0 500.0 600.0 700.0 800.0 Time (hr) 00 1300 200,0 3000 4000 0000 600.0 700.0 800,00 Time (hr)

Figure 3.o. 1-3: Comparison of Concentrations of Metals (continued on the next page)

NL-08-025 Page 103 of 125 Case 3 Case 4 Case 3 Al Ralba**

Case 4 Al Release so-60 40-j20 C

0.0 100.0 200.0 300.0 400.0 500.0 600.

700.0 800.0 16,,. (hr) 0.0 100.0 200.0 300.0 400.0 000.0 600.0 700.0 800.0 Time (hr)

Case 3 Ca Release Case 4 Ca Release 70-300 j44 S30~

j20 300

-Case 4IACAP(Ca) 300 Case 4 Vuez (Ca) 200 cISO 50 0

0.0 100.0 200.0 300.0 400.0 50000 6000 700.0 200.0 Time (hr) 0.0 100.0 200.0 300.0 400.0 000.0 200.0 700.0 000.0 Time. (hr)

Case 3 Si Release Case 421i Release so 70 460 20 1 0 0

60 I

I1 II U

U 0.0 100.0 2000 300.0 400.0 0000 600.0 700.0 600.0 Time (hr) 1.0 100.0 200.0 300.0 400.0 000.0 600.0 700.0 800.

Time (hr)

Figure 3.o.1-3: Comparison of Concentrations of Metals (continued from the previous page)

N L-08-025 Page 104 of 125 Development of the Bump-up Factor The chemical bump-up factor (CBU) is defined as the ratio of the head loss (dP) over time versus the demineralized water or non-chemical effects head loss. The CBU with temperature is another representation of the 30 day head loss for each of the loops (referenced to the non-chemical head loss) - it also contains the effects of viscosity in the head loss term. By factoring out viscosity in the head loss, the CBU without temperature is developed. The CBU without temperature is the chemical effects bump up factor and represents the impact of chemical effects over the non-chemical debris head loss. The CBU primarily occurs during the buffer addition, but is considered a chemical effect within the first 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

The CBU are currently being developed based on testing performed at VUEZ.

Entergv Response to Issue 30.2.1.

Entergy did not perform a simplified chemical effects analysis. The conservative debris generation and transport analyses postulate sufficient debris materials to cover the recirculation sump screens in the event of a design basis accident.

Entergy Response to Issue 3o.2.2.i There are four break cases that were determined to be representative of bounding plant conditions as far as fibrous and particulate debris for chemical effects head loss testing. The four break cases are the Unit 2 VC ABLOCA (combined cases), Unit 2 1IR LBLOCA (combined cases), Unit 3 VC ABLOCA (combined cases), and Unit 3 VC ABLOCA (case 6) which generated the bounding debris cases. The debris loads selected for the 30-day head loss testing are based on the maximum debris possible and therefore, the most conservative loads for head loss. For the debris loads on the strainer, the maximum occurrence of each individual debris constituent within the evaluated break case was combined to produce the maximum load.

The basis and assumptions for the development of the particular debris beds tested are as follows:

Test cases 1 through 4:

Based on the information from the debris generation and transport calculations, the four cases to be run in the VUEZ loops are:

• Unit 3 VC ABLOCA,

• Unit 2 VC ABLOCA,

• Unit 2 IR LBLOCA, and

• Unit 3 VC ABLOCA (case 6)

The rational is as follows:

1) For both Units, the IR ABLOCA cases have similar debris to their respective VC ABLOCA cases except that the approach velocity to the strainer is approximately 1.3-2.0 times

-higher. This effect is expected to increase the likely impact of chemical effects. This has been seen in prior testing for the case of debris bed thickness variation. The debris quantities for the IR cases are lower than those for the VC cases due to the significantly larger screen area available for debris in the IR sump as compared to the VC sump. Thus, each of the IR ABLOCA cases are bounded by the chemical effects seen in each of the two

NL-08-025 Page 105 of 125 unit's respective VC ABLOCA cases selected.

2) The two VC ABLOCA cases selected have similar debris bed thickness (-0.8") and similar approach velocities (-0.7 ft/sec). The key difference between them is the total bed solidity, which for Unit 2 is greater than the value for Unit 3 (12.1 % vs. 9.6%). It is expected that the impact of chemical precipitates is higher for the higher solidity bed (less void space in the debris bed to accommodate a similar quantity of chemical precipitates).

3) The Unit 2 IR LBLOCA case has very similar debris characteristics to the Unit 3 VC ABLOCA case. Debris bed thickness (11.10" vs. 0.85") and bed solidity (6.50% vs. 9.60%)

are approximately the same (within -20%). The main difference between the two cases is the strainer approach velocity (0.00500 ft/s vs. 0.00755 ft/s); with the VC case having -50%

greater velocity than the I R case. Because the higher velocity for the VC case would result in greater bed compression and hence slightly higher bed solidity, it is reasonable to consider that the impact of chemical effects would be greatest for the VC sump. This also provides specific case data demonstrating that the IR strainer can accommodate the chemical effects from a worst case of debris generation for a Large Break accident case.

4) The Unit 3 VC ABLOCA "Case 6" is the fourth VUEZ test case. "Case 6" represents the maximum Particulate/Fiber Mass Ratio'and the maximum Total Bed Solidity (%) condition for both Units 2 and 3 and is also a better representation of a thinner bed than the other initial three recommended cases. In addition, a 0.38" equivalent debris bed thickness is expected to be sufficiently thick in order to avoid thin bed phenomenon. To ensure that is correct, this condition will be examined in the pre-test. If any "clean screen" behavior is observed, additional fiber will be added to this case to avoid the thin bed phenomenon.

Finally, this case represents an actual plant debris load case, rather than a combined case and is thus more representative of plant conditions.

Entergy Response to Issue 3o.2.3.i PH Range The chemical constituents in post-LOCA circulating Unit 2 and Unit 3 containment fluids are boric acid, hydrochloric acid, nitric acid, and sodium tetraborate (NaTB).

The concentration of these constituents is presented below.

Table 3.o.2.3-1: Chemicals in Post-LOCA Containment Fluids Plant Unit 2 I

Unit 3 I

Unit 2 I

Unit 3 Break

[VC ABLOCA VC ABLOCA IR LBLOCA VC ABLOCA Chemical Addition Maximum Boron (ppm) 2,570 2,408 2,570 2,408 Minimum Boron (ppm) 2,004 2,002 2,004 2,002 Maximum Lithium (ppm) 3.9 3.78 3.9 3.78 Minimum Lithium (ppm) 0.33 0.33 0.33 0.33 Hydrochloric Acid (mole) 59.35 59.35 59.35 59.35 Nitric Acid (mole) 557.7 557.7 557.7 557.7 NaTB Buffer (Ibm) 8,096 - 10,000 8,096 - 10,000 8,096 - 10,000 8,096 -10,00

N L-08-025 Page 106 of 125 Hydrochloric acid (HOI) can be formed from the degradation of cable insulation material, as well as nitric acid (HNO 3) possibly formed due to the radiolysis of the'atmospheric nitrogen (N2) and oxygen (02) in the containment vapor space.

For Unit 2, the prescribed quantities of hydrochloric acid (HOI) and nitric acid (HNO 3) are 59.35 mole and 557.7 mole. To convert these values to test quantities, first they are converted into a concentration (ppm) by dividing them by the water volume in the plant (measured in liters) and multiplying the result by the atomic weight of each acid. To obtain the mass of HCl and HN0 3 that were used during testing, the acid concentrations were multiplied by the volume of the water in the test apparatus (measured in lit ers).

The prescribed concentration of boron for Unit 2 was 2,570 ppm. To o btain the mass of boric acid required to achieve the aforementioned boron concentration, the following relation was used:

Mass _ BoricAcid(mg) = Test - Vol.(L)

• B - Conc( ppm)

• Atomic -Wt.

_ BoricAcid AtomicWt._B The maximum and minimum concentrations of lithium for Unit 2 were 3.9 ppmn and 0.33 ppm, respectively. To obtain the masses of lithium hydroxide (LiOH) required to achieve the aforementioned lithium concentrations, the following relation were used:

Atomic _ Wt. -'LiOH Mass _ LiOH(mg) = Test _ Vol.(L)

• Li - Conc(ppm)*

Atomic _Wt.

_Li Similar calculations were performed for Unit 3 to obtain the quantities of HCl, HNO 3, and mass of boric acid.

The prescribed mass of the NaTB buffer is 10,000 Ibm for both Units. This represents the maximum NaTB buffer quantity and is conservative. This value represents the maximum buffer quantity, which ensures that the pH is well above 7 and consequently more towards the basic side of the system equilibrium. A more basic solution causes the aluminum in the system to significantly impact corrosion. Therefore, using the maximum buffer quantity drives the system in a more conservative direction in regards to interaction of aluminum. In addition, using the maximum buffer quantity does not impact the influence of zinc onto the system. Zinc is relatively inert in the pH range of 7 to 12 and appreciably reactive in an acidic environment. For both Units, the pH in containment is above 7 for radiological purposes. As such, the maximum buff er quantity which drives the system to be more basic conservatively models the impact of aluminum and zinc in the system.

To obtain the scaled mass of NaTB buffer that was used in the test apparatus, the total buffer mass was multiplied by the volume scaling factor.

Using standard VUEZ procedures, beaker(s) of buffer solution were prepared such that buffer addition commenced at the, time of recirculation onset (50 minutes). This was conservative in that the test was subject to high acidity (low pH) even though the buffer begins to react once the pool level reaches the NaTB baskets. Buffer addition was performed using standard VUEZ procedures, a gradual process designed to ensure even distribution of buffer in the test loop.

NL-08-025 Page107 of 125, The pH of the fluid during the IP tests was determined by the interaction of acids, materials and buffer introduced into the test tank. The quantities of acids, materials and buffer entered into the test tank were as specified in Table 3o.2.3-2.

Table 3o.2.3-2: Chemical Concentrations for Unit 2 and Unit 3 Material Unit 2 Unit, 3 HCL - Hydrochloric Acid 1.5 1.5 PPM HN0 3 - Nitric Acid 24.6 24.8 PPM LiOH - Lithium Hydroxide (max) 13.5 13.0 ppmn LiOH - Lithium Hydroxide (min) 1.1 1.1 ppIM Boric Acid 14699.6 13773.0 ppmn NaTB 3177.0 3207.2 ppmn For information only, the expected pH range for both Units is 7.1 to 7.6.

Therefore, in keeping with this guidance, the NaTB buffer introduction for testing began at 50 minutes after test execution.

T he range of pH for the VUEZ chemical effect head loss testing, was 5.6 to 7.5. Although the lower bound pH may have been slightly higher than expected due to the dissolution of materials in the demnineralized water portion of the experiment, the levels of calcium in the experiment were in excess of those recorded in ICET. Therefore, the VUEZ testing is representative of the expected conditions.

Temperature History The temperature history expected in a post-LOCA environment is highly dependent upon plant operation scenarios and the nature of the break causing the LOCA. The maximum sump temperature usually occurs shortly after the break event and gradually decreases over the remainder of the ECCS mission time. Two different temperature profiles were considered relating to the large break post-LOCA event. The first profile was designated "Minimum ECCS (NUREG-1465)" and is referred to herein as the "NUREG-1465" profile. The second, designated "Maximum ECOS" for each reactor was based upon calculations estimating the maximum temperature profile that might be expected during a LOCA event.

The data served as the basis for establishing a composite sump temperature profile for each reactor, This composite profile used the more conservative portions of each calculated profile. The composite profile was estimated from the above-described profile data as follows:

1. From time t=0 to t=1 0,000 sec, the composite profile was assumed to be the maximum value of the two profiles;

2. From time t=1 0,000 sec to W= 00,000 sec, the composite profile was assumed to be a weighted average of the two profiles. The weighting factor (WF) used was a linear function.

based upon time and increased from 0 to 1 over the time range mentioned. The resulting factor was applied as follows:

S"mplL,omposite =SumpTNUREGI1 4 6 5

• WF + SuimpTEccs _ MLý (1 - WF)

3. From time t = 100,000 sec to 2,592,000 sec, the composite profile was assumed to be

-equal to the NUREG71465 profile.

NL-08-025 Page 108 of 125

4. During the final stages of the profile, the minimum temperature in the respective NUREG-1465 profiles was assumed.

These profiles form the basis from which the test temperature profiles were developed and provide the most conservative conditions over the entire length of the LOCA event. The resulting composite profiles can be found below in Figure 3o.2.3-1 and Figure 3o.2.3-2. The resulting hybrid test temperature profile is appropriate and conservative for the following reasons:

1. It incorporates the highest and longest reasonable peak temperatures, permitting the maximum extent of chemical activity (e.g., corrosion, dissolution, leaching) that could be expected during an accident scenario of this type).

2. It incorporates the lowest temperature at the end of the test to develop an estimate of maximum head loss in the presence of chemical effects for any Unit 2 & 3 temperature profile, ensuring that the maximum amount of precipitate will be formed and provides liquid properties that are more conducive to higher head loss conditions.

Figure 3o.2.3-1: Sump temperature profile for Unit 2 post-LOCA scenario

NL-08-025 Page 109 of 125 Figure 3o.2.3-2: Sump temperature profile for Unit 3 post-LOCA scenario The VUEZ test apparatus has a high temperature limit of 190 OF [87.8 *C]. As can be seen from Figure 3o.2.3-1 and Figure 3o.2.3-2, the composite sump temperature assumed for the containment for each unit is higher than the VUEZ maximum operating temperature. For Unit 2, the sump temperature is higher than 190 OF for the first approximately 20 hours2.314815e-4 days <br />0.00556 hours <br />3.306878e-5 weeks <br />7.61e-6 months <br /> of the post-LOCA event, 17.8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> for Unit 3. The use of a hybrid temperature profile for the test provides a more representative scenario for chemical attack and subsequent precipitation than a single temperature held for the full length of the experiment. The graph in Figure 3o.2.3-3 provides more detail on the composite temperature profiles for the two units over the first 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of the postulated post-LOCA event. Figure 3o.2.3-3 compares the composite temperature profile to the maximum temperature that the test unit is capable of providing (labeled "VUEZ upper limit" on the graph). To account for the elevated corrosion, dissolution, or reaction rates that are assumed to occur at design sump temperatures, and which exceed the apparatus temperature limit of 190 OF, approximate rate expressions as a function of temperature were used to compensate for the reaction rate difference.

NL-08-025 Page 110of 125 Figure 3o.2.3-3: Composite profiles vs. VUEZ upper temperature limit In general terms, the rates of most chemical reactions increase as the system temperature increases. This is due to a minor extent by the increase in collision frequency of molecules in a specific system and to a much greater extent by an increase in the percentage of molecules in a system that have sufficient energy to exceed the activation energy of a particular reaction. This doesn't necessarily apply to reactions which occur essentially instantaneously, such as precipitation reactions due to ionic reactions in solution, however can apply to reactions such as corrosion. The simulation was achieved by insertion of additional amounts of Aluminum, NukonTm (silicon), and concrete (Calcium) for the portion of the experiment during the time the hybrid profile temperatures exceed I 90*F (87.8*C).

Figure 3o.2.3-4 and Figure 3o.2.3-5 compare the VUEZ temperature profile to the plant specific composite temperature profile for Unit 2 and Unit 3, respectively.

NL-08-025 Page 111 of 125 300 250 r200 150 100-so P2 Sump Temperature

-Case 1 and 2 Vuez Test Temp.

0 100 200 300 400 500 600 700 800 Tim.s (hr)

Figure 3o.2.3-4: Composite profiles vs. VUEZ temperature profile for Unit 2 300 P3 Sump Temperature

-Case 3 and 4 Vuez Test Temp.

250

'200 E15

~100 50 0

100 200 300 400 500 600 700 800 Time (hr)

Figure 3o.2.3-5: Composite profiles vs. VUEZ temperature profile for Unit 3 Duration of Spray The Unit 2 & 3 containment sprays operate for 3.4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> and 4.0 hours0 days <br />0 hours <br />0 weeks <br />0 months <br />, respectively. Therefore all materials, whether indicated as submerged or un-submerged, were submerged in the test. This is more conservative due to more interaction between test materials and test solution then would occur by spray contact only. After the required spray time passed, the unsubmerged material was

NL-08-025 Page 112 of 125 raised out of -the test apparatus pool solution with the remainder of materials staying in contact with the solution for 30 days.

Materials The materials in containment that are available and considered for reaction with the containment fluids include aluminum, copper, carbon steel, zinc in galvanized steel, zinc coating and concrete.

Enteray Response to Issue 3o.2.4.i ALION Science & Technology performed the plant specific chemical effects evaluation and testing.

The testing performed was 30 day integrated chemical debris head loss testing at the VUEZ test facility. No WCAP-1 6530 precipitate based head loss testing was performed on the replacement sump screen.

The 30 day testing was performed similar to that of ICIET but with the addition of debris head loss capability. The screen installed in the experiment was a horizontally oriented flat plate on which the plant specific debris bed was developed and head loss measured. Pa~t studies have shown that, in general, uniform beds in flat plate testing produce higher head losses than the vertically oriented advanced screen designs. The most compelling reason for this is gravity. Vertical screens tend to load non-uniformly and therefore produce lower overall head losses. The debris bed developed, in the VUEZ test loop provides a* representative debris bed (bed thickness and composition) and the impact of chemical effects was measured over, the 30 day mission time. The increase in head loss over the 30 day mission time in the chemical environmen~t is attributed to chemical effects. The chemical effects will be applied to the full scale non-chemical prototype debris head loss through a multiplicative or 'bump-up" factor derived from the 30 day test results.

Entergy Response to Issue 3o.2.5.i Indian Point does not use the WCAP or AECL model for evaluating chemical effects.

Enteray Response to Issue 3o.2.6 throucih 3o.2.17 Indian Point does not use the WCAP or AECL model for evaluating chemical effects.

Entergy Response to Issue 3o.2.18.i Alion Science & Technology performed the integrated chemical effects head loss evaluation at the VUEZ test facility.

Enterpv Response to Issue 3o.2.19.i The first critical parameter is the corrosive interactions of the spray and pool fluid chemistry with those materials and debris sources in containment and resident on the sump screen. The integrated chemical effect head loss testing was designed to replicate this concern.. These potential interactions may cause additional precipitates and/or impacts on debris head loss over the 30-day mission time. To provide a representative experiment, certain scaled parameters were selected to ensure that the reactions take place in the correct quantity and'environment and that the resulting debris head losses satisfactorily reflected any chemical effects.

NL-08-025 Page 113 of 125 The test tank was intended to represent the containment conditions with respect to pool liquid volume and chemistry, temperature, materials, and impact on debris head loss. To replicate the corrosion potential of the structural materials inside containment, the experiment preserved the material surface area to sump pool volume similar to the Integrated Chemical Effects Test (ICET)

Project. Past experience with these types of corrosion experiments have shown that the release rate is based on surface area of the material.

Fibrous debris materials were also resident in the pool. These debris materials were large and small pieces of insulation. Since insulation pieces are a collection of uniform glass fibers, the mass-of these materials were scaled to the pool volume.

The second critical parameter relates to debris head loss. Debris head loss is dependent upon fluid temperature, flow rate or approach velocity through the bed, and debris bed thickness and constituency. The experiment replicated the prototype screen debris bed thickness and composition (porosity).

'The scale testing was configured to achieve the following conditions:

I 1. The test apparatus screen average fluid approach velocity (vave) was equal to the containment sump screen average approach velocity. Where vave was equal to the flow rate (0) divided by the screen area (As).

2. The test apparatus minimum flow rate (Qmin) was at least 1 liter/minute or greater to preclude stagnant flow regions within the test tank.

3. The ratio of the test screen surface area to tank volume was as close as reasonably achievable to that of the containment sump surface area to pool volume.

4. The fibrous debris bed thickness (ti) on the screen of the test apparatus was equal to the containment sump screen equivalent debris bed thickness.

By ensuring that the above scaling conditions were met, the experiment made available the necessary corrosion products and debris bed conditions representative of the plant containment conditions.

The. scaling factor for submerged materials was based on the ratio of test tank water volume to containment water volume.

The submerged debris amounts were a result of subtracting the sump screen debris amount (transported) from the total submerged amount (total generated).

Ideally, for the VUEZ test apparatus to fully represent the submerged quantity of fiber expected to exist in plant containment following a LOCA, the debris scaling factor (ratio of gross test screen area to gross plant screen area) and the pool volume scaling factor (ratio of test volume to plant containment volume) should be similar. However, for each test case, these scaling factors were appreciably different from each other.

To account for this discrepancy, scaled make-up submerged fiber quantities were computed for each type of fibrous debris. The following relation demonstrates this calculation:

M/ake __ Fiber = Yvcreen -P 1 6,cr (SFV,I, - SFe where:

Vscreen = Volume of fiber on the screen, ft3 Pfiber =Material density of fiber, ibm/ft 3

NL-08-025 Page 114 of 125 S,,= Volume scaling factor S~deb = Debris scaling factor Once the scaled make-up fiber quantity was computed for each type of fibrous debris, the quantity was added to the scaled submerged fiber quantity.

The debris materials placed at the test screen, such as NukonTM (surrogate for latent fiber, fiberglass, and Thermal-Wrap), Mineral Wool, Calciu m-Silicate, Temp-Mat, Paint Coatings, Latent Debris etc., were calculated based on a ratio of the test screen area (At,) to the plant sump screen area (APS). The scaling factor for sump screen materials was based on the ratio of the test screen ar 'ea to sump screen area. This scaling factor was larger than the aforementioned water volume scaling factor.

Enterpy Response to Issue 3o.2.19.ii The VUEZ tests in the small loops were not intended to determine or replace the actual head loss data associated with the vendor non-chemical prototype hardware debris head loss testing.

Rather, the VUEZ testing was designed to conservatively represent the flow conditions and debris loadings on the vendor prototype testing. The purpose of the test were to develop a debris bed of similar porosity and thickness to aid in determining relative increases in head loss due to chemical effects.

The debris bed composition and thickness selected for the IP VUEZ chemical effects experiments were based on the range of plant. specific debris loads and size characteristics validated in the plant-specific prototype testing and head loss analyses. Based on the results of the debris generation and transport analysis, the final debris characteristics on the sump screen contained three (3) sizes of fibrous debris: fines, small pieces (< 6" on a side), and large pieces (> 6" on a side). Although the distribution of these sizes varies depends on the load case, all three (3) were represented in the plant specific debris load at the screen. For the VUEZ experiment however, a conservative (smaller) size distribution was selected that primarily represented Classes 1 through 5 in Table 3-2 and Figure 3-3 (NUREG/CR-6808). A smaller size distribution produces higher head losses than the larger pieces.

Because the gravitational settling velocity of the debris as it is being deposited on the strainer plate is high relative to the natural approach velocity of the flow through the strainer plate, a slow rate of addition was taken to ensure that random non-uniformities in debris distribution on the plate surface did not occur. The technique used by the VUEZ technicians was designed to produce a uniform and homogenous debris bed. In this way, any temporary variations in bed porosity (thickness) would result in flow being redistributed to other portions of the strainer such that debris was preferentially collected there. Finally, a visual inspection of the resulting bed was performed to ens ure that relative uniformity was achieved. Manual adjustments to the bed were made for small improvements in uniformity.

Residual non-uniformity in the debris distribution of a poured bed was significantly less than the non-uniformity exhibited in the collection of debris on actual strainer hardware. Illustrations of the actual debris beds are shown in Figure 3.o-1.

N L-08-025 Page 115 of 125 Table 3-2 Size Classiftiction Scheme for Fibrous Debris" No.

Descrpton 1

~Very small pieces of fiberglaiss mateuial; 4mcoscap c' fics, Oha appear

~imm~ to be cylinders of varying LID.

2 Single, flexible strandts of fiberglass;- essentialty acts as a suspending strand.

3 MAiple attached or interwoven strands that exdiibit considerable flexibillity and that, because of random orientatons induced by turbulent dtrag, can exhibit low settling velociie.

4 Fiber clusters that have more rigidity than Class 3 debris and noat react to drag forces assa senu-nigid body.

5 Clurnps of fibrous debris that have been noted to sat when saturated with water. Generated by diferent mewthod by vanou researchers but easily created by manual shredding of fiber nutting.

6

~Larger clumps, of fibers lying between Classes 5Sand T 7

Fragments of fiber tha retain some aspects of the anginal rectangular conshtruco of the fiber matting-Typicaly precut piece of a large blatet to simulate moderate-size segments of original blankiet.

Figure 3-3. Fiberglass Insulation Debris of Two Example Size Classes Enteravy Response to Issue 3o.2.20.i A section view of the test tank is shown in Figure 3o.2.20-1. The tank is confined and contains approximately 59 liters of solution. The flow rates used for the experiments were in the range of 1 liter per minute. This provided a pool turnover every hour. The discharge of the pump into the tank is shown on the left in the figure and points downward to ensure that flow swept materials off

N L-08-025 Page 116 of 125 the floor and circulated the solution through the materials submerged in the tank. The flow was drawn down through the chimney section on the right hand side of the tank. Based on configuration, there are very few stagnant areas in the test tank. In comparison, there are many obstructions in the IP 2/3 plant containments that would promote stagnant areas or eddies inhibiting the coolant flow around materials. The tank is conservative from a flow and transport perspective due to it's simplicity compared to the flow paths in containment.

Figure 3o.2.20-1: Diagram of Elisa Small Loop

N L-08-025 Page 117 of 125,.

Entergy Response to issue 3o.2.2 1 (i)

Alion's VUEZ CE Test Program Was designed to replicate the potential corrosive interactions of the spray and pool fluid chemistry with those materials and debris sources in containment and resident on the sump screen. These potential interactions can cause precipitates and/or impacts on debris head loss over IP 2/3's 30-day mission time. A conservative, representative experiment was developed to ensure that the reactions take place in the correct quantity and environment and that the resulting debris head losses satisfactorily reflected any chemical effects. Critical plant parameters included sump screen area, recirculation fluid volume, recirculation flow rate, containment debris, and recirculation pool chemistry (temperature and pH).

The test tank represented the containment parameters to replicate the corrosion potential of the structural materials inside containment. The experiment preserved the material surface area to pool volume similar to the integrated chemical effects testing (ICET) experiments; past experience with these types of corrosion experiments have shown that the release rate is based on surface area of the material. Chemical loads that are present in the containment pool were replicated by using the same concentration (ppm by weight value) in testing as is present in IP 2/3's containments. The temperature and pH curves that would be present in the containment pool were also represented during testing.

The containment materials included were divided into the three categories corresponding to where the materials would lie within the test tank: submerged, unsubmerged, and on the sump screen.

Each category was scaled according to either pool volume ratio or screen area ratio of the plant versus the test apparatus based on the transport characteristics or residence of the debris within containment.

The chemical effects testing parameters were derived from the containment parameters and are conservative for the following reasons:

1. The quantities of materials that contribute to chemical effects were provided by the plant personn 'el based on a review of plant design documents, walkdowns and conservative estimates. The materials included in the experiments were concrete, aluminum, zinc, copper, carbon steel, dirt/dust and LOCA generated debris. Metallic coatings were represented by sheet materials.

2. The scale between the containment material to pool volume and experiment material to pool volume was preserved.

3. The tests were conducted at the maximnum testing temperature of 1900 F until such time as the sump temperature analytically falls below 1900 F. For the remaining time, the test temperature profile was the same as the containment sump temperature profile.

4. For the part of the test that the sump analytical temperature is greater than 1 900 F, the test materials were conservatively adjusted (increased) to ensure that the total amount of material was released over that time and temperature. This was implemented through the addition and removal of temporary materials at the beginning of the experiment. The quantities of,temporary materials werebased on the release rates provided in WCAP-16530.

N L-08-025 Page 118 of 125

5. The test fluid pH profile throughout the test was based on design basis containment sump pH profile or quantities of buffer in containment.

Temperature Adi ustment/Temporarv Material To provide a conservative and representative experiment, it was necessary to ensure that the quantity of corrosion products released in the plant containment environment were reproduced in the test environment such that the resulting debris head losses satisfactorily reflected the plant's chemical effects. Since the experiment had a limit of 1900 F, adjustment was required to ensure the quantity of material released at 1900 F in the experiment equaled the quantity-of materials released at temperatures above 1900 F.

The elemental release rates were determined based on the method and equations in WOAP-16530-NP and on the Arrhenius principle. The release rates from the plant and test profiles were correlated to determine material adjustments for the chemical effects testing to conservatively generate the chemical effects products that would not otherwise be generated since the post LOCA containment and sump temperatures are higher than the maximum operating temperature than what could be attained in the test apparatus.

The test method focused on the pre-recirculation time period and on the post recirculation time period up to the time the sump temperature dropped to 190 OF. In these time periods the plant's temperature profile was higher than the test apparatus temperature profile. The higher the plant's temperature, the higher chemical release rates and consequently the higher the total releases. To match the plant's total releases during this period above 1 9Q0 F, the quantity of material in the test apparatus was increased until such time the sump analytical temperature fell below 1 900 F. The method used to determine the additional quantity of materials was based on the method and.

equations in TR-WCAP-16530-NP.

The TR-WCAP-1 6530-NP method first evaluates the elemental release rates of Al, Si and Ca as a function of time, for the time period that the plant sump temperature is higher than 190 OF, for the respective plant and test temperature and pH profiles. The elemental release rates of Al, Si and Ca as a function of time for. these time periods are then calculated and the ratio of the elemental releases (sumpNUEZ test) as a function of time determined. These elemental ratios of the release rates are integrated as a function of time. The integrated ratios of the release rates show the relationship between the plant and test time that would result in the generation of equal releases of Al, Si and Ca within a time interval of interest. The results of this evaluation can be used to determine the test material adjustment that would generate the same integrated releases within any time period that the plant temperature exceeds the test temperature.

Acids and Bases HCl and HN0 3 acids and LiOH are generated post-LOCA inside containment and were introduced in the test apparatus in an effort to match the containment sump pH.

The experiment began with the addition of the requisite amount of boron through the addition of boric acid (in most cases near 2800 ppm). The pH during this phase is between 4 and 5.

Reviewing the industry experiments, ALION benchtop experiments and VUEZ results have revealed that the primary release during this phase is calcium and it is not overly sensitive to small changes in pH units. Results to date are all in reasonable agreement on the quantities of calcium released. The HCl and HN03 acids are not generated immediately and adding them early to the experiment would have the effect of pushing the pH down below 4 and be overly conservative -

N L-08-025 Page 119 of 125 this would also require more than the requisite amount of buffer to be added to bring the pH up to target. The goal of the experiment was to maintain the chemistry within reasonable design basis pH limits to capture the corrosion that occurs during the pH extremes without altering the chemistry significantly. Achieving a pH between 4 and 5 accomplishes the corrosion/release of calcium.

The amount of buffer was based on a review of the plant design bases. The experiment considered the maximum amount of buffer being physically added to containment to ensure the maximum pH was bounded. The higher the pH, the higher the corrosion of aluminum therefore it was critical that the maximum pH was identified and the correct amount of buffer added to the experiment. As stated, the value of pH was identified from a review of plant specific design documents. No attempt was made to increase or artificially decrease the pH beyond the design bases value. By ensuring the maximum pH, the experiment maximized the concentration of aluminum. However, lowering the pH, lowers the solubility limit of aluminum and promotes precipitation and subsequent head loss. For example, relative corrosion rates and solubility limits are presented in Figure 3o.2.21-1 and Figure 3o.2.21-2.

____----1000 (Alsolbilty]vs T(F) 12M Figure~~~~~~~~~~~~~~~~~~0 3022-:Auiu ees CP63 igr o22-:Auiu ouiiyv Temperatur From~~~~~~ ths8iuew.a5eaieteafc f Ho lmnmslbiiy sson h solbiit o aumnu i gealyreucd henloerngth p fom8. (30pp)

-o8.543pp)

Although~~1 this-8.

col-ersn infcn muto rcpttotecroinrt rp signficntl fro pH8.5to

75.

rovdinga hgh H toprootecorrsio ofalumnumandthe loweingthe H t prmotesolbilty wuldnotreprsen a raliticcondtio asthe H cnno dro aprcal ovrte37a.vet4LO a efomdmr hn10eprmnswt togthe experiment forinu comletse hemistry inawyFhtmintaied the.2-2 Almaimum anduminimumv corosuiityon prodiuct is.

Theimactl oftedacids ohn lowering the pH fove the (300 day ento is 30p loeinsgniiath due to thmoe smalamuniltsy n would nonl accousnt forealsi mindimaeution.ah pH cno vaiTionsal hne n Hd o

along the courses of the experiment.i elzdtruhntrlratos

NL-08-025 Page 120 of 125 Enterav Response to Issue 3o.2.21.ii Figures 3.o.2.21 -3 through -5.

1Time history - IP/Case I TET UEZSEQ#4 14 13.

12.

11-10 8,

I 5-4-

3-0.

• 1 Y

4 -

21-PDIýR1.1 [I(P aj TEST SART

__PDIR1.2[KPaJ 4'

-TIRC1.

[sI.CI

-FIRI

[lonin)

M3B038 &.0 pH-Cl 25 ZMf SaO.P).

88)00 'B' 8M1C' Bt8hD FB Cr0.80.

Sub-~g.4 M.0)8.I 100-900 80 70 80 5

4 E-0 071 'i......

.. I...

I......

I.....................

50 1140800 0711141400 071114 2000 0711150200 0711150800 0711151400 0711152000 0711160200 0711188808O Daterrime Figure 3.o.2.21-3: 30 Day CE Head Loss Testing Pressure Drop Time History (Case 1)

NL-08-025 Page 121 of 125

[L-UT UEZSEQ*4 ITime history - IPICase 21 14-13.

12.

Ii 10-9-

[7~

6 -6 5-4-

3-2.

0-0, 3 M

q 00 60 40 20D 5

4 3-0 071113 0000 I

.I I I I,

0712030000 0712G000000 0712130000O 0711180000 0711230000O 07112800000 Date/Time Figure 3.o2.21-4: 30 Day CE Head Loss Testing Pressure Drop Time History (Case 2) lU&SEQJ ITime history - IP/ýse3 14 13 12 11 10

-7 5-4-

3-12 0~

5.

~3 2 -

FDIR3I Ke PDR3.2 [KPo TIRCA1 [St CI TreqC3 FIR3 [101,10]

4-

~0 Fle A4justmoro

-a-pH C3 25 DW - Make Up Waler Addiben I ~~~V

"'T-**

100 40 E 20-0 5

2 U-0711141200

.7111.1200 0711241200 0711291200 0712041200 0712091200 0712141200 Daterrime Figure 3.o.2.21-5: 30 Day CE Head Loss Testing Pressure Drop Time History (Case 3)

NL-08-025 Page 122 of 125 Time history - IP/Case 4 14.

123 12-10-9-

8~

7 4-3-

2~

0~

100 40 E 20-0 1200 5

4 2..

0 071127 t200 Date[Time Figure 3.o.2.21-6: 30 Day CE Head Loss Testing Pressure Drop Time History (Case 4)

Enter-nv Response to Issue 3o.2.22.i The details and technical basis for application of a bump-up factor are currently being developed.

USNRC Issue 3D:

Licensing Basis 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. That is, provide a general description of and planned schedule for any changes to the plant licensing bases resulting from any analysis or plant modifications made to ensure compliance with the regulatory requirements listed in the Applicable Regulatory Requirements section of this generic letter. Any licensing actions or exemption requests needed to support changes to the plant licensing basis should be included. 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.

Enterav Response to Issue 3y:

One license basis change to the Unit 2 containment buffering agent has been requested and approved by the NRC. This change and additional requests as discussed below were or will be made to ensure compliance with the regulatory requirements listed in the GL and are summarized below.

Containment Sump Buffering A~gent Modification (Unit 2)

N L-08-025 Page 123 of 125 Due to the potential interaction of accident-generated debris with a combination of certain materials in the VC, borated water, and existing pH buffer (Trisodium Phosphate (TSP)), the quantity and physical nature of that debris is ultimately affected. The accumulation of the modified debris at the sump strainers may be such that the head loss across the strainers reduces pump NPSH margin to an unacceptable degree. It has been predicted through testing and chemical analysis that specific Unit 2 calcium silicate-bearing insulation debris may react negatively with the boric acid and TSP in the VC water to yield a greater head loss across the strainers. It is planned to replace the present TSP buffer with Sodium Tetraborate (NaTB) during the spring 2008 refueling outage.

On February 7, 2008, the NRC approved and issued Amendment No. 253 (Reference 22) to the Facility Operating License changing the containment buffering agent from TSP to sodium tetraborate decahydrate NaTB.

Containment Sump Buffering Agent Modification (Unit 3)

A similar buffer replacement is planned for Unit 3 (Sodium Hydroxide (NaOH) to NaTB) subject to a license amendment submission and approval.

Proposed Changie to the Updated Final Safety Analysis Report Regarding the Emergency C6re Cooling System and Component Cooling Water System Single Passive Failure Analysis and Recirculation Phase Backup Capability (Units 2 and 3)

The purpose of this proposed change to the licensing basis is to establish the following quantitative basis for passive failures:

1.

Revise the ECCS single passive failure analysis such that passive failures are assumed to occur 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> or greater after event initiation

2.

Revise the Unit 2 CCWS single passive failure analysis such that passive failures are assumed to occur 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> or greater after event initiation

3.

Revise the recirculation phase backup capability such that the residual heat removal pumps would be used if backup capacity to the internal recirculation loop is required in the event of an ECOS or COWS (Unit 2 only) passive failure 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> after event initiation The requested licensing basis changes will be made under current licensing basis assumptions for analyzing the effects of post-accident debris blockage. The demonstration that the recirculation and containment sump strain 'er designs are capable of accommodating the GL 2004-02 licensing basis debris loads, including chemical effects, will be addressed by the additional GL 2004-02 supplementary submittals as required by the granted extension requests.

References 1.- Nuclear Eh-ergy Irn~titute Ddcumendt NEI'04-07, Volume 1, Revision 0,""Pressurizbd-_Water Reactor (PWR) Sump Performance Methodology," dated December, 2004.

2. Safety Evaluation by the Office of Nuclear Reactor Regulation Related to NRC

NL-08-025 Page 124 of 125 Generic Letter 2004-02, published as Volume 2 of Nuclear Energy Institute Guidance Report (NEI 04-07), 'Pressurized Water Reactor Sump Performance Evaluation Methodology,"

dated December 6, 2004.

3. Generic Letter 2004-02, "Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at P ressu rized -Water Reactors," dated September 13, 2004

4. NL-05-023, "90-Day Response to NRC Generic Letter 2004-02, Potential Impact of Debris Blockage on Emergency Recirculation during Design Basis Accidents at Pressurized-Water Reactors", dated February 28, 2005.

5. NL-05-094, "Response to NRC Generic Letter 2004-02, Potential Impact of Debris Blockage on Emergency Recirculation during Design Basis Accidents at Pressurized-Water Reactors",

dated September 1, 2005.

6. NL-05-1 33, "Supplemental Response to NRC Generic Letter 2004-02, Potential Impact of Debris Blockage on Emergency Recirculation during Design Basis Accidents at Pressurized-Water Reactors", dated December 15, 2005.

7. NL-07-074, "Request for Extension of Completion Date for Indian Point Unit 2 Corrective Actions and Modifications Required by Generic Letter 2004-02, Potential Impact of Debris Blockage on Emergency Recirculation during Design Basis Accidents at Pressurized-Water Reactors", dated September 17, 2007.

8. NL-07-129, "Revised Request for Extension of Completion Date for Indian Point Unit 3 Corrective Actions and Modifications Required by Generic Letter 2004-02, Potential Impact of Debris Blockage on Emergency Recirculation during Design Basis Accidents at P ressu rized -Water Reactors", dated December 3, 2007.

9. NRC letter to Mr. M. Balduzzi, "Indian Point Nuclear Generating Unit No. 2 - Approval of Extension Request for Corrective Actions Required by Generic Letter 2004-02", dated November 20, 2007.

10. NRC letter to Mr. M. Balduzzi, "Indian Point Nuclear Generating Unit No. 3 " Approval of Revised Extension Request for Corrective Actions Required by Generic Letter 2004-02",

dated December 20, 2007.

11. NRC letter to A. Pietrangelo (Nuclear Energy Institute), "Revised Content Guide for Generic Letter 2004-02 Supplemental Responses", dated November 21, 2007.

12. NRC letter to Mr. M. Balduzzi, "Indian Point Nuclear Generating Unit Nos. 2 and 3 - Draft Open Items fromn Staff Audit of Corrective Actions to Address Generic Letter 2004-02", dated January 31, 2008.

13. NUREG/CR-6224, "Parametric Study of the Potential for BWR ECCS Strainer Blockage. Due to LOCA-Generated Debris", dated October 1995.

14. D.V. Rao, et al., Drywell Debris Transport Study: Experimental Work, NUREG/CR-6369, Volume 2, September 1999.

NL-08-025 Page 125 of 125

15. Nuclear Energy Institute Document (NEI 02-01) "Condition Assessment Guidelines: Debris Sources Inside PWR Containment' Revision 1, dated September, 2002.

16. Boiling Water Reactor Owner's Group Document NEDO-32686-A, Utility Resolution Guidance for ECOS Suction Strainer Blockage, Volume 1, dated October, 1998.

17. NUREG/CR-6772, GSI-1 91: Separate Effects of Debris Transport in Water, 2002.

18. NUREG/CR-6808, Knowledge Base for the Effect of Debris on PWR Emergency Core Cooling Sump Performance, dated February, 2003.

19. NUREG/CR-6916, Hydraulic Transport of Coating Debris, dated December, 2006.

20. WCAP-16568-P, "Jet I mpingement Testing to Determine the Zone of Influence (ZOI) for DBA Qualified/ Acceptable Coatings," Revision 0.

21. WCAP-1 6406-P, "Evaluation of Downstream Sump Debris Effects in Support of GSI-191," Revision 1.

22. NRC letter to Mr. Balduzzi, "Indian Point Nuclear Generating Unit No. 2 - Issuance of amendment re: Changes to Technical Specifications to Replace Trisodium Phosphate Buffer with Sodium Tetraborate", dated February 7, 2007.

ATTACHMENT 2 TO NL-08-025 INDIAN POINT UNIT 2 and 3 Supplemental Response to NRC Generic Letter 2004-02 Emergency Core Cooling Syste~m Single Line Drawings' ENTERGY NUCLEAR OPERATIONS, INC INDIAN POINT NUCLEAR GENERATING UNITS 2 AND 3 DOCKETS 50-247 AND 50-286 1 Note - These drawings are simplified for training and not controlled

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