Text

Final Response to NRC Generic Letter 2004-02: Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized Water Reactors and Associated Request for Additional Information
	ML082520025
Person / Time
Site:	Cook
Issue date:	08/29/2008
From:	Weber L; Indiana Michigan Power Co
To:	; Document Control Desk, Office of Nuclear Reactor Regulation
References
	AEP-NRC-2008-17
	Download: ML082520025 (64)
	v • d • e

IIndiana Michigan Power Company Nuclear Generation Group INDIANA One Cook Place MICHIGAN Bridgman, MI 49106 POWER aep.com August 29, 2008 AEP-NRC-2008-17 10,CFR 50.54(f)

Docket Nos.: 50-315 50-316 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk 11555 Rockville Pike Rockville, Maryland 20852 Donald C. Cook Nuclear Plant Units 1 and 2 FINAL RESPONSE TO NUCLEAR REGULATORY COMMISSION GENERIC LETTER 2004-02:

POTENTIAL IMPACT OF DEBRIS BLOCKAGE ON EMERGENCY RECIRCULATION DURING DESIGN BASIS ACCIDENTS AT PRESSURIZED WATER REACTORS AND ASSOCIATED REQUEST FOR ADDITIONAL INFORMATION This letter provides I&M's final response to GL 2004-02 and an associated RAI. The documents referenced in this letter and its attachments are identified in Attachment 1. The abbreviations and acronyms are defined in Attachment 2.

By GL 2004-02 (Reference 1), the NRC identified concerns regarding the potential for post-accident debris to impede or prevent the recirculation functions of emergency core cooling and containment spray systems at PWRs. The NRC requested that PWR licensees mechanistically evaluate this potential for their plants and identify corrective measures that would be taken.

The NRC subsequently issued an RAI regarding initial information provided in response to GL 2004-02.

By Reference 2, I&M provided a supplemental response to GL 2004-02 and the associated RAI that superseded previous responses. In that supplemental response, I&M stated that, by May 31, 2008, I&M would achieve compliance with the regulatory requirements listed in the Applicable Regulatory Requirements section of GL 2004-02.

I&M also stated in the supplemental response that a final response would be submitted within 90 days of achieving compliance with those requirements.

This letter provides that final response to GL 2004-02 for CNP. to this letter provides the final response to GL 2004-02 and the associated RAI (Reference 3) for CNP in the form of a supplement to Attachment 3 to Reference 2. Attachment 4 to this letter provides a table showing the three outstanding questions from the RAI and identifying the location of the requested information. Attachment 5 to this letter provides a 30-Day Integrated Chemical Effects Test report from ALION Science and Technology. Attachment 6 to this letter provides photographs from testing performed on cold galvanizing compound.

U. S. Nuclear Regulatory Commission AEP-NRC-2008-17 Page 2 This letter contains no new regulatory commitments.

Should you have any questions, please contact Mr. John A. Zwolinski, Regulatory Affairs Manager, at (269) 466-2478.

Sincerel Lawrence J. Weber Site Vice President JRW/rdw Attachments

1.

References

2.

Abbreviations and Acronyms

3.

Final Response to GL 2004-02 and Request for Additional Information

4.

Response to NRC Request for Additional Information

5.

ALION report: Summary Report for Impact of Chemical Effects on Containment Sump Strainer Head Loss - D. C. Cook Units 1 and 2

6.

Cold Galvanizing Compound Testing Photographs c:

T. A. Beltz, NRC Washington, DC J. L. Caldwell - NRC Region III K. D. Curry - AEP Ft. Wayne (w/o attachments)

J. T. King - MPSC (w/o attachments)

MDEQ - WHMD/RPS (w/o attachments)

NRC Resident Inspector

U. S. Nuclear Regulatory Commission Page 3 AEP-NRC-2008-17 AFFIRMATION I, Lawrence J. Weber, being duly sworn, state that I am Site Vice President of Indiana Michigan Power Company (I&M), that I am authorized to sign and file this request with the Nuclear Regulatory Commission on behalf of I&M, and that the statements made and the matters set forth herein pertaining to I&M are true and correct to the best of my knowledge, information, and belief.

Indiana Michigan Power Company Lawrence J. Weber Site Vice President SWORN TO AND SUBSCRIBED BEFORE ME THIS DAY OF k..Lt.3+

,2008 Notary Public My Commission Expires

bucfeei, Boren Coufl, N

ATTACHMENT 1 TO AEP-NRC-2008-17 REFERENCES

1)

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

dated September 13, 2004 (ML042360586).

2)

Letter from M. A. Peifer, I&M, to NRC Document Control Desk, "Supplemental Response to Nuclear Regulatory Commission Generic Letter 2004-02: Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized-Water Reactors,"

AEP:NRC:8054-02, dated February 29, 2008 (ML080770394, ML080770395, ML080770396, ML080770400, and ML080770404).

3)

Letter from P. S. Tam, NRC, to M. K. Nazar, I&M, "Donald C. Cook Nuclear Plant, Units 1 and 2 - Request for Additional Information Re: Response to Generic Letter 2004-02,

'Potential Impact of Debris Blockage on Emergency Recirculation During Design-Basis Accidents at Pressurized-Water Reactors' (TAC Nos. MC4679 and MC4680)," dated February 9, 2006 (ML060370547).

4)

Letter from W. H. Ruland, NRC, to A. Pietrangelo, NEI, "Revised Content Guide for Generic Letter 2004-02 Supplemental Responses," dated November 21, 2007 (ML073110269 and ML073110278).

5)

Letter from P. S. Tam, NRC, to M. K. Nazar, I&M, "Donald C. Cook Nuclear Plant, Unit 1 (DCCNP-1) - Extension of Completion Date for Actions in Response to Generic Letter 2004-02 (TAC No. MC4679)," dated July 28, 2006 (ML062020768).

6)

Letter from P. S. Tam, NRC, to M. W. Rencheck, I&M, "Donald C. Cook Nuclear Plant, Units 1 and 2 -

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

Extension Request Approval" (TAC NOS.

MC4679 and MD4680),

dated December 26, 2007 (ML073540189).

7)

Letter from P. S. Tam, NRC, to M. K. Nazar, I&M, "Donald C. Cook Nuclear Plant, Units 1 and 2 (DCCNP-1 and DCCNP-2) - Issuance of Amendments Re:

Containment Sump Modifications per Generic Letter 2004-02 (TAC Nos. MD5901 and MD5902)", dated October 18, 2007 (ML072780605).

8)

EPRI Technical Report, 1011753, "Design Basis Accident Testing of Pressurized Water Reactor Unqualified Original Equipment Manufacturer Coatings," dated September 2005.

9)

K&L Report No. 08-0424, "Radiation Tolerance and Design Basis Accident Testing of Cold Galvanizing Compound ZRC TM," dated April 24, 2008.

10)

ALION Report, ALION-REP-AEP-4462-12, Revision 0, "Debris Measurement and Examination Test Report for D. C. Cook Nuclear Plant Step #1."

11)

CNP UFSAR Change Request (UCR) 1917, Revision 0.

to AEP:NRC:2008-17 Page 2

12)

CCI Calculation, 3 SA-096.056, Revision 3, "Structural Analysis of the Remote Strainer."

13)

I&M Calculation, SD-060307-003, Revision 1, "Qualification of Waterway and Waterway Supports for Remote Strainer 1 -STN-321 for EC-0000047994..'

14)

I&M Calculation, SD-070315-001, Revision 0, "Qualification of Waterway and Waterway Supports for Remote Strainer 2-STN-321 for EC-0000047800."

15)

Westinghouse, WCAP-16406-P, Revision 1, "Evaluation of Downstream Sump Debris Effects in Support of GSI-191," dated August 2007.

16)

NRC SER, Topical Report (TR) WCAP-16406-P, Revision 1, "Evaluation of Downstream Sump Debris Effects in Support of GSI-191," PWR Owners Group, Project No. 694 (ML073520295).

17)

S&L Calculation, 2008-08883, Revision 1, "GSI-1 91 Downstream Effects - Wear Analysis of ECCS Components."

18)

I&M Calculation, MD-12-CONT-004-N, Revision 0, "Emergency Core Cooling System and Containment Spray System Performance Considering System and Component Wear Evaluated for the. Resolution of GSI-1 91."

19)

Westinghouse, WCAP-16793-NP, Revision 0,

"Evaluation of Long-Term Cooling Considering Particulate, Fibrous and Chemical Debris in the Recirculating Fluid," dated May 2007.

20)

Letter, W. H. Ruland, NRC, to A. R. Pietrangelo, NEI, "Draft Conditions and Limitations for Use of Westinghouse Topical Report WCAP-16793-NP, Revision 0, "Evaluation of Long-Term Cooling Considering Particulate, Fibrous and Chemical Debris in the Recirculating Fluid"," dated February 4, 2008.

21)

Letter from PWROG to PWROG Systems and Equipment Engineering Subcommittee GSI-191 Point of Contact, "Transmittal of Additional Guidance for Modeling Post-LOCA Core Deposition with LOCADM Document for WCAP-16793-NP (PA-SEE-0312)," dated December 14, 2007.

22)

CCI Test Report, 680-41404, Revision 0, "Bypass Tests."

23)

Letter from W. H. Ruland, NRC, to A. R. Pietrangelo, NEI, "Revised Guidance for Review of Licensee Responses to Generic Letter 2004-02, Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized Water Reactors,"

dated March 28, 2008 (ML080230234).

24)

ALION Report, ALION-REP-AEP-4459-03, Revision 0, "Summary Report for Impact of Chemical Effects on Containment Sump Strainer Head Loss - D. C. Cook Units 1 And 2."

ATTACHMENT 2 TO AEP-NRC-2008-17 ABBREVIATIONS AND ACRONYMS AEP American Electric Power ALION ALION Science and Technology ANSI American National Standards Institute ASTM American Society for Testing and Materials Cal-Sil calcium silicate insulation CCI Control Components Incorporated CC centrifugal charging CFR Code of Federal Regulations CNP Donald C. Cook Nuclear Plant CTS Containment Spray System DBA design basis accident DEGB double ended guillotine break DFT dry film thickne~s DGBS debris generation break size DI debris interceptor ECCS Emergency Core Cooling System EPRI Electric Power Research Institute ERG Emergency Response Guideline ESF engineered safety features OF degrees Fahrenheit FME foreign material exclusion ft feet ft abs feet of water absolute GDC General Design Criteria GL Generic Letter gpm gallons per minute GR NEI 04-07 Guidance Report ICET Integrated Chemical Effects Test I&M Indiana Michigan Power Company in inches IST in-service test K&L Keeler and Long, PPG Industries LBLOCA large break loss of coolant accident Ibm pounds-mass lbs pounds LOCA loss of coolant accident m

meter MFTL Multi-Functional Test Loop mil 0.001 in Min-K micro-porous insulation mm millimeter.

Pm micro-meter NEI Nuclear Energy Institute NPSH net positive suction head NPSHa net positive suction head actual NPSHr net positive suction head required NRC Nuclear Regulatory Commission ppm parts per million PSDC Plant Specific Design Criteria psig pounds per square inch - gauge PVC polyvinyl chloride PWR pressurized water reactor RAI request for additional information RCP reactor coolant pump RCS Reactor Coolant System RES Research RFO refueling outage RG Regulatory Guide RHR Residual Heat Removal RMI reflective metal insulation SBLOCA small break loss of coolant accident SER NEI 04-07 Safety Evaluation Report SE Safety Evaluation Sl safety injection S&L Sargent & Lundy LLC TMD transient mass distribution TS Technical Specification UFSAR Updated Final Safety Analysis Report WOG Westinghouse Owners Group ZOI zone of influence

ATTACHMENT 3 TO AEP-NRC-2008-17 FINAL RESPONSE TO GL 2004-02 AND REQUEST FOR ADDITIONAL INFORMATION Table Of Contents Section Topic Paqe Summary-Level Description 2

1.

Overall Compliance 6

2.

General Description of and Schedule for Corrective Actions 7

3.

Specific Information Regarding Methodology for Demonstrating Compliance

a.

Break Selection 9

b.

Debris Generation/Zone of Influence (ZOI) (excluding coatings) 9

c.

Debris Characteristics 15

d.

Latent Debris 15

e.

Debris Transport 21

f.

Head Loss and Vortexing 21

g.

Net Positive Suction Head (NPSH) 23

h.

Coatings Evaluation 25

i.

Debris Source Term 25

j.

Screen Modification Package 28

k.

Sump Structural Analysis 29 I.

Upstream Effects 30

m.

Downstream Effects - Components and Systems 31

n.

Downstream Effects - Fuel and Vessel 33

o.

Chemical Effects 35

p.

Licensing Basis 52 Conclusions 55 to AEP-NRC-2008-17 Page 2 FINAL RESPONSE TO GL 2004-02 AND REQUEST FOR ADDITIONAL INFORMATION This attachment provides I&M's final response to GL 2004-02 in the form of a supplement to to Reference 2. Consistent with Attachment 3 to Reference 2, this attachment follows the format and guidance provided by the NRC in Reference 4.

This attachment addresses all sections of Attachment 3 to Reference 2.

Each section of this attachment indicates whether the section constitutes a revision that supersedes the corresponding section of Attachment 3 to Reference 2, or whether the section provides information that is additional to that provided in the corresponding section of Attachment 3 to Reference 2. This attachment also addresses the three 2006 RAIs from Reference 3 that were not completely addressed in Reference 2. The text from the NRC guidance provided by Reference 4 is presented in italic script.

NRC Request, Summary-Level Description The GL supplemental response should begin with a summary-level description of the approach chosen. This summary should identify key aspects of design modifications, process changes, and supporting analyses that the licensee believes are relevant or important to the NRC staff's verification that corrective actions to address the GL are adequate. The summary should address significant conservatisms and margins that are used to provide high confidence the issue has been addressed even with uncertainties remaining. Licensees should address commitments and/or descriptions of plant programs that support conclusions.

Summary-Level Description for CNP The key aspects of the approach chosen by I&M to resolve the concerns identified in GL 2004-02 remain unchanged from those stated in Reference 2, Attachment 3 but are restated below for clarity. The key aspects are:

Extensive design modifications to significantly reduce the potential effects of post-accident debris and latent material on the functions of the ECCS and CTS during the recirculation phase of accident mitigation.

Extensive testing and analysis to determine break locations, identify and quantify debris sources, quantify debris transport, determine upstream and downstream effects, and confirm the recirculation function.

Use of the Alternate Evaluation methodology as described in Chapter 6 of the GR and SER.

Changes to the CNP licensing basis, including TS changes, to reflect the plant modifications, and the change to a mechanistic sump strainer blockage evaluation.

Extensive changes to plant programs, processes, and procedures to limit the introduction of materials into containment that could adversely impact the recirculation function, and establish monitoring programs to ensure containment conditions will continue to support the recirculation function.

to AEP-NRC-2008-17 Page 3 Application of conservative measures to assure adequate margins throughout the actions taken to address the GL 2004-02 concerns.

The following information is in addition to that provided in the Reference 2 Attachment 3 Summary Level Description.

Design Modifications The following modifications were performed in Unit 1 during the Spring 2008 RFO.

A remote strainer and waterway were installed. The remote strainer provides approximately 1072 ft2 of strainer area with the same strainer opening sizes as the Unit 2 strainer.

Debris interceptors were installed on the loop compartment side of the flood-up overflow wall to prevent debris from blocking the flood-up overflow wall openings. This assures sufficient water inventory would be available to the remote strainer.

The five existing 10 inch diameter openings in the flood-up overflow wall were modified to reduce head loss. Additionally, the radiation shields on the annulus side of the openings were modified to assure water flowing through the openings would not be restricted by small debris.

A significant quantity of labels and other miscellaneous debris sources (tape, PVC jacketing, etc.) was removed.

The foam insulation on the non-essential service water supply lines inside the crane wall within potential zones of influence was double-jacketed with stainless steel material with additional jacketing bands to support the tested configuration described in Reference 2.

Testing I&M has completed testing at K&L for determination of the potential failure modes and quantities of cold galvanizing compound under DBA conditions. This testing determined that a very small percentage (< 5%) of the organic compound failed during the testing.

I&M does not intend to re-perform strainer head loss testing using this reduced quantity of failed cold galvanizing material, but does consider this reduced quantity to represent available margin for consideration of the total quantity of particulate debris available in the post-LOCA containment pool that potentially affects strainer head loss.

I&M did use the results of the testing to inform the ex-vessel downstream effects wear evaluation, while maintaining significant conservatism for the input value.

I&M has completed evaluation of the 30-Day Integrated Chemical Effects Test report provided by ALION for the CNP-specific testing which was performed in the large test loop at the Vuez Test Facility.

The ALION 30-day integrated chemical effects testing resulted in a proposed increase factor of 1.4 above the debris only head loss.

As described in Reference 2, I&M applied a conservative factor of 1.7 for the head loss associated with chemical effects testing to to AEP-NRC-2008-17 Page 4 the debris only head loss results, in lieu of the percentage increase determined during the CC[

testing.

I&M has conservatively chosen to maintain, as part of the design basis, the 1.7 increase factor for strainer head loss above the factored debris only head loss developed from the CCI large scale testing.

Analyses I&M has verified that the analyses previously performed to structurally qualify the remote strainer remained bounding for the installation performed during the Unit 1 Spring 2008 RFO. A minor update of one of the calculations was required based on the as installed configuration.

The plant modifications completed during the Unit 1 Spring 2008 RFO were conservatively qualified to meet the CNP design and licensing basis that existed at the time of installation, and the new design and licensing basis that became effective on May 31, 2008. That new design and licensing basis includes the mechanistic evaluation of the effect of post-accident debris on the ECCS and CTS recirculation function as described in this letter.

An analysis of ex-vessel wear, abrasion, erosion, and pump blockage has been completed using the guidance of WCAP-16406-P, Revision 1, as clarified and accepted by the associated NRC Safety Evaluation Report. The results of this evaluation determined that the RHR, CTS, and CC systems will successfully operate for a minimum 30 day mission time.

Using the guidance of WCAP-1 6406-P, Revision 1, it was determined that, after approximately 15 days of operation with debris-laden fluid, the SI pumps could experience excessive vibration.

I&M determined that the required mission time for the SI pumps is a maximum of 30 hours3.472222e-4 days 0.00833 hours 4.960317e-5 weeks 1.1415e-5 months following a LOCA.

Procedures have been changed to clarify existing guidance regarding removal of unnecessary equipment from service to protect the SI pumps and maintain them available for future use, if needed. The analysis of ex-vessel wear, abrasion, erosion, and pump blockage was performed by S&L.

An analysis of the in-vessel blockage, localized debris buildup, and plate-out has been completed. This analysis was performed in accordance with WCAP-16793 using the LOCADM analysis methodology. This analysis determined that fuel assembly bottom nozzle blockage will not occur and the plate-out of debris on the fuel clad surfaces will result in a maximum 'total deposition thickness of 17 mils and a maximum cladding temperature of 366°F. This analysis was performed by Westinghouse.

An analysis was completed of water samples that were collected during debris only head loss testing at CCI. These samples were collected after a stable head loss was achieved at 100%

flow and 100% debris conditions. The results of this analysis established a concentration of debris in the water that varied from approximately 2 ppm at about 26 hours3.009259e-4 days 0.00722 hours 4.298942e-5 weeks 9.893e-6 months following 100%

debris addition to 199 ppm at about 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months following 100% debris addition. These results were for those tests that included the DEGB debris quantities which based on the test pool volume had the potential to yield a maximum concentration of approximately 5200 to 5400 ppm. These concentrations demonstrate the filtering capability of the CNP strainer 'system which provides significant conservatism to the assumptions used for debris quantities that would be resident in the systems downstream of the strainers and the time period for which those quantities of debris are assumed to exist. The water sample analysis was performed by ALION.

to AEP-NRC-2008-17 Page 5 Changqes to the Licensing Basis I&M has completed changes to the CNP UFSAR to recognize the mechanistic evaluation of the effect of post-accident debris on the ECCS and CTS recirculation function, as described in this letter and Reference 2. I&M has also completed changes to the UFSAR to reflect the physical changes to the plant, and those programmatic and process changes that support the adoption of, and maintenance of, the mechanistic methodology.

I&M has obtained NRC approval of TS changes that reflect the GL 2004-02 related plant modifications and provide new TS Surveillance Requirements as necessary to assure that important components are operable to support the recirculation function. In accordance with the requirements of the associated amendment request, these new TS requirements have been implemented in Unit 1.

Improvements in Processes and Programs I&M has completed the review of plant procedures, processes, and programs and has updated those procedures and design specifications or standards that will ensure the analysis inputs and assumptions can be maintained. The changes to those programs and processes determined to be necessary to support the transition to the mechanistic evaluation methodology licensing basis were in place prior to, or at the time of the change to the licensing basis. The other changes completed since Reference 2 was submitted consist principally of changes to plant implementing procedures and engineering documents to prevent the introduction of debris sources that could reduce the available sacrificial strainer margin.

Conservatisms and Margins I&M applied conservative measures to assure adequate margins throughout the actions taken to address the GL 2004-02 concerns. The key areas in which these conservative measures were applied were provided in Reference 2. Subsequent to completion of the analysis and testing described above, the following additional conservatisms were identified.

Debris Generation I&M conservatively assumed that 100% of the conservatively determined quantity of cold galvanizing compound in containment failed and was available for transport to the recirculation sump strainers. Based on the results of the testing performed, less than 5% of the material failed, representing a reduction of approximately 738 lbs of particulate that would be available for transport to the strainers.

to AEP-NRC-2008-17 Page 6 Ex-Vessel Downstream Effects I&M conservatively assumed that approximately 221 lbs of cold galvanizing compound particulate would pass through the strainers for ex-vessel downstream effects analysis. This is conservative with respect to the quantity of cold galvanizing compound that could be expected to fail based on the cold galvanizing compound testing performed.

Chemical Effects A bump-up factor of 1.7 was applied to the results of the chemical effects testing rather than the determined maximum increase of 1.4 from the 30-day integrated chemical effects testing.

NRC Request - 2006 RAI Licensees should ensure that GL supplemental response information fully address issues identified in the RAIs provided to each licensee in early 2006. A separate response to the RAIs is not necessary if they are appropriately addressed in the-GL supplemental response.

I&M Response to 2006 RAI The three 2006 RAIs (Reference 3) that were not completely addressed in Reference 2 are addressed in this attachment. Attachment 4 to this letter provides a table identifying the location of the requested information.

NRC Information Item 1 - Overall Compliance:

Provide information requested in GL 2004-02 Requested Information Item 2(a) regarding compliance with regulations.

GL 2004-02 Requested Information Item 2(a)

Confirmation that the ECCS and CSS [CTS at CNP] 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 GL.

This submittal should address the configuration of the plant that will exist once all modifications required for regulatory compliance have been made and this licensing basis has been updated to reflect the results of the analysis described above.

I&M Response to Information Item 1 The confirmation statement provided in Reference 2 indicated that analyses, licensing basis changes, and plant modifications remained to be completed.

The confirmation statement provided below reflects the completion of these activities, and supersedes that provided in Reference 2.

to AEP-NRC-2008-17 Page 7 Confirmation I&M has completed all necessary analyses and updated the CNP licensing basis to reflect that the ECCS and CTS recirculation functions under debris loading conditions are in compliance with the regulatory requiremerits listed in the Applicable Regulatory Requirements section of GL 2004-02. I&M has completed all associated plant modifications in Unit 1 and Unit 2.

Applicable Regulatory Requirements The applicable regulatory requirements identified in GL 2004-02 are:

10 CFR 50.46 "Acceptance Criteria for Emergency Core Cooling Systems for Light-Water Nuclear Power Reactors" 10 CFR 50.67 "Accident Source.Term" 10 CFR 100 "Reactor Site Criteria" For plants not licensed to the GDC in 10 CFR 50, Appendix A, such as CNP, the applicable regulatory requirements include plant-specific design criteria in their licensing basis similar to the following: Criterion 35, "Emergency Core Cooling," Criterion 38, "Containment Heat Removal," Criterion 41, "Containment Atmosphere Cleanup."

Plant Configuration The plant modifications that have been completed in Unit 1 and Unit 2 include: replacement of recirculation sump trash racks and screens with a main pocket-style strainer, installation of a remote pocket-style strainer assembly, creation of a waterway between the remote strainer and the recirculation sump, installation of level instruments in the recirculation sump, reconfiguration of sump vents, installation of debris interceptors at key locations, modification of various flowpaths, and removal of significant debris sources.

NRC Information Item 2 - General Description of and Schedule for Corrective Actions:

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). (Note: All requests, for extension should be submitted to the NRC as soon as the need becomes clear, preferably not later than October 1, 2007.)

GL 2004-02 Requested Information Item 2(b)

A general description of and implementation schedule for all corrective actions, including any plant modifications, that you identified while responding to this GL.

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 to AEP-NRC-2008-17 Page 8 December 31, 2007, describe how the regulatory requirements discussed in the Applicable Regulatory Requirements section will be met until the corrective actions are completed.

I&M Response to Information Item 2 The general description of, and schedule for, corrective actions provided in Reference 2 reflected the analyses, licensing basis changes, and plant modifications that remained to be completed. The general description provided below reflects the completion of these activities, and supersedes that provided in Reference 2.

The corrective actions to address the concerns identified in GL 2004-02 at CNP consisted of plant modifications, testing and analysis, changes to plant programs and processes, and changes to the licensing basis. These actions have been completed in accordance with I&M regulatory commitments and NRC-approved extensions.

The completion dates for these actions are provided below.

Plant Modifications The plant modifications needed to address the GL 2004-02 concerns were completed in Unit 2 during the Fall 2007 RFO, which ended November 6, 2007. Except as approved by References 5 and 6, these modifications were completed in Unit 1 during the Fall 2006 RFO. As approved by References 5 and 6, certain Unit 1 modifications were completed prior to entry into Mode 4 at the end of the Spring 2008 RFO.

Testing and Analyses Except as approved by Reference 6, the testing and analyses needed to address GL 2004-02 concerns were completed by December 31, 2007.

As approved by Reference 6, certain analyses were completed prior to May 31, 2008.

Plant Programs and Processes Significant program and process changes necessary to address the GL 2004-02 concerns were completed by December 31, 2007, and additional changes were completed by May 31, 2008.

Licensing Basis The licensing basis changes needed to address the GL 2004-02 concerns consist of UFSAR changes related to the plant modifications implemented to resolve the concerns identified in GL 2004-02, TS changes related to those plant modifications, and licensing basis changes to reflect the mechanistic evaluation of the effect of post-accident debris on the ECCS and CTS recirculation functions.

The UFSAR changes related to the Unit 2 GL 2004-02 plant modifications were made effective during the Fall 2007 RFO. Except as approved by Reference 6, the UFSAR changes related to the Unit 1 GL 2004-02 plant modifications were made effective during the Fall 2006 RFO. As to AEP-NRC-2008-17 Page 9 approved by Reference 6, the UFSAR changes related to certain Unit 1 GL 2004-02 modifications were made effective prior to entry into Mode 4 at the end of the Spring 2008 RFO.

The TS changes related to the GL 2004-02 plant modifications were implemented for Unit 2 prior to entry into Mode 4 during the Fall 2007 RFO.

In accordance with Reference 7 and Reference 6, the TS changes related to the GL 2004-02 plant modifications were implemented for Unit 1 prior to entry into Mode 4 at the end of the Spring 2008 Unit 1 RFO.

In accordance with Reference 6, the CNP licensing basis was changed to reflect the mechanistic evaluation of the effect of post-accident debris on the ECCS and CTS recirculation function by May 31, 2008.

3. Specific Information Regarding Methodology for Demonstrating Compliance:

NRC Information Item 3.a - 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.

I&M Response to Information Item 3.a The information provided in the Reference 2 response to Information Item 3.a remains applicable.

NRC Information Item 3.b Debris Generation/Zone of Influence (ZOI) (excluding coatings)

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

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

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

to AEP-NRC-2008-17 Page 10

3. Identify if destruction testing was conducted to determine ZOls. If such testing has not been previously submitted to the NRC 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.

I&M Response to Information Items 3.b.1 and 3.b.2 The following information is in addition to that provided in the Reference 2 response to Information Items 3.b.1 and 3.b.2.

Table 3bl-3, as provided in Reference 2, includes as one of its inputs, the bounding quantity of unqualified labels in Unit 1 and Unit 2 containments. As indicated in that table, walkdown data for Unit 1 and 2 conservatively established a bounding quantity of 25.94 ft2 of unqualified labels in containment. The as-left quantity of unqualified labels in Unit 2, based on the final walkdowns performed during the Fall 2007 RFO was 9.58 ft2. The as-left quantity of unqualified labels in Unit 1, based on the final walkdowns performed during the Spring 2008 RFO was 12.31 ft2.

Table 3bW-3 Latent Debris Location Unit 1 and Unit 2 Bounding Values Debris Type Upper Loop Pipe Ice Total Containment Compartment Annulus Condenser Latent Fiber, lbs 5.4 15.6 8.4 0.6 30 Latent Dirt/Dust, lbs 30.6 88.4 47.6 3.4 170 Electromark Labels

- break in Loop 1 or 21.8 30.48 52.28 Loop 4, ft 2 "

Electromark Labels

- break in Loop 2 or 20.14 30.48 50.62 Loop,3, ft2 Unqualified Labels, ft2 8.77 13.62 3.55 25.94 Flexible Conduit PVC Jacketing, ft2 1.57 1.57 Ice Storage Bag Fibers, ft2 5.0 5.0 Ice Storage Bag Liner Shards, ft2 0.87 0.87 Pieces of Rubber from platform where 0.22 0.22 ice bags were opened, ft2 I

to AEP-NRC-2008-17 Page 11 I&M Response to Information Item 3.b.3 With the exception of the information provided in the following paragraphs regarding cold galvanizing compound testing, the information provided in the Reference 2 response to Information Item 3.b.3 remains applicable.

Cold Galvanizing Compound Testinq Testing has been performed of the cold galvanizing compound that was used in the Unit 1 and Unit 2 containments to touch up areas where welding was performed on galvanized steel surfaces including cable trays, ventilation systems, ice condenser panels, etc. The purpose of this testing was to determine the quantity of material that would fail during DBA conditions to reduce the quantity of material that would be assumed to pass through the strainers and impact components downstream of the strainers.

The testing that was performed is similar to the testing that was performed for Reference 8, Design Basis Accident Testing of Pressurized Water Reactor Unqualified Original Equipment Manufacturer Coatings, EPRI Technical Report 1011753, September 2005. The testing was performed for I&M by K&L (Reference 9).

A total of 9 test coupons were prepared for the testing. The coupons consisted of three (3) each of:

Galvanized steel plate, coated with ZRCTM cold galvanizing compound.

Galvanized steel plate welded to galvanized steel plate, coated with ZRCTM cold galvanizing compound.

Galvanized steel plate welded to uncoated carbon steel plate, coated with ZRCTM cold galvanizing compound.

The coupons were approximately 2 in by 4 in to 2 in by 6 in.

The plate thickness used for fabrication of the coupons was 1/4 in. The coupons were coated with ZRCTM cold galvanizing compound with a resulting DFT of approximately 1 to 4 mils.

Pre-test photographs of the coupons are included in Attachment 6.

The testing was performed with the following conditions and requirements:

" Coupons were exposed to a radiation dose of 3.44 x 108 Rads, at a dose rate of 1.02 x 106 Rads/hr.

The DBA testing was performed for 48 hours5.555556e-4 days 0.0133 hours 7.936508e-5 weeks 1.8264e-5 months following irradiation.

The temperature during DBA testing was performed at 235°F for five minutes followed by

a rapid drop to 1900F, holding at 190°F for 20 minutes, then slowly decreasing to 1200F over the next 47 hours5.439815e-4 days 0.0131 hours 7.771164e-5 weeks 1.78835e-5 months 30 minutes.

The pressure in the autoclave was established at 12 psig for the first four hours followed by a drop to 0 psig over the next 43 hours4.976852e-4 days 0.0119 hours 7.109788e-5 weeks 1.63615e-5 months 30 minutes.

The chemistry of the solution was established at 2000 ppm boric acid with a pH of approximately 9.0. NaOH was used to establish the pH in the solution.

to AEP-NRC-2008-17 Page 12 Approximately one half of the length of each of the coupons was submerged for the duration of the test, in the recirculating fluid, while the remainder of each of the coupons was sprayed with solution for the duration of the test.

A dual recirculation filter arrangement was used for the test. One filter was in service at a time. The in-service filters were swapped and replaced every half hour for the first six hours of the test, then after 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months , 30 hours3.472222e-4 days 0.00833 hours 4.960317e-5 weeks 1.1415e-5 months , and 48 hours5.555556e-4 days 0.0133 hours 7.936508e-5 weeks 1.8264e-5 months (conclusion of the test).

The filters were photographed following removal. These photographs are included in.

The status of the coupons was assessed following irradiation, within two hours following the 48 hour5.555556e-4 days 0.0133 hours 7.936508e-5 weeks 1.8264e-5 months DBA test, and then at 14 days after the end of the test. The coupons were photographed at each assessment. These photographs are included in Attachment 6.

The 48-hour duration was chosen since the expected duration for containment spray is expected to be less than 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months , and the majority of the cold galvanizing compound in the containments of CNP Unit 1 and Unit 2 exist in those areas that would only be subjected to spray.

The results of the assessments performed following each stage of the testing are contained in Table A:N:2008-17-3.b.3-1 below.

Table A:N:2008-17-3.b.3-1 Test Assessment Results Post-(1)

DBA End + 14 Coupon Irradiation DBA End + 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months days (2)

CNPCG1-1 Coating intact, Color is lighter, no other defects.

No change from Front no defects.

2 hour2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months evaluation.

CNPCG1-1 Coating intact, Color is lighter, no other defects.

No change from Back no defects.

2 hour2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months evaluation.

CNPCG1-2 Coating intact,

4 few and #6 medium intact blistering, No change from Front no defects, color is lighter, no other defects.

2 hour2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months evaluation.

CNPCG1-2 Coating intact, Color is lighter, no other defects.

No change from Back no defects.

2 hour2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months evaluation.

CNPCG1-3 Coating intact, Color is lighter, no other defects.

No change from Front no defects.

2 hour2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months evaluation.

CNPCG1-3 Coating intact,

8 medium intact blistering, color is lighter, No change from Back no defects, no other defects.

2 hour2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months evaluation.

A#4 few and #6 medium dense blistering.

CNPCG2-1 Coating intact, 10 to1%o'h otnghsdmntd No change from Front no defects.

10 to 12% of the coating has delaminated.

2 hour2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months evaluation.

Color is lighter, no other defects.

CNPCG2-1 Coating intact,

6 medium dense intact blistering. 1% of No change from Back no defects, the coating has delaminated. Color is 2 hour2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months evaluation.

lighter, no other defects.

2_hourevaluation.

CNPCG2-2 Coating intact,

6 medium intact blistering in center of No change from Front no defects.

panel. Color is lighter, no other defects.

2 hour2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months evaluation.

CNPCG2-2 Coating intact,

2 few, #6 medium dense intact blistering.-.- No change from Back no defects.

Color is lighter, no other defects.

2 hour2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months evaluation.

to AEP-NRC-2008-17 Page 13 Test.

Assessment Results Test Post-DBA End + 14 Coupon Irradiation DBA End + 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months (1)d

+21

___days (2)

CNPCG2-3 Coating intact,

6 medium dense and #8 medium dense No change from Front "

no defects.

intact blistering on lower half of panel.

2 hour2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months evaluation.

Color is lighter, no other defects.

CNPCG2-3 Coating intact, No change from BackColor is lighter, no other defects.

2 hour2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months evaluation.

CNPCG3-1 Coating intact,

6 and #8 medium dense intact blistering.

No change from Front no defects.

Color is lighter, no other defects.

2 hour2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months evaluation.

CNPCG3-1 Coating intact, Color is lighter, no other defects.

No change from Back no defects.

2 hour2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months evaluation.

CNPCG3-2 Coating intact, Coor is lighter, not other defects.

No change from Front no defects.

2 hour2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months evaluation.

CNPCG3-2 Coating intact,

4 few, #6 and #8 medium dense intact No 6hange from Back no defects.

blistering. Color is lighter, no other 2 hour2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months evaluation.

defects.

CNPCG3-3 Coating intact,

4 few and #6 dense intact blistering.

No change from Front no defects.

Color is lighter, no other defects.

2 hour2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months evaluation.

8 medium dense intact blistering on CNPCG3-3 Coating intact, center of panel and #6 medium dense No change from Back no defects.

intact blistering on lower half of panel.

2 hour2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months evaluation.

Color is lighter, no other defects.

(1) Assessment per ANSI N101.2-1972 (2) Assessment per ASTM D-3911 Based on the post-test assessments performed, only one of the coupons experienced any loss of coatings material. The assumed face surface area of all of the coupons, not counting the edges, is 96 in2. The quantity of failed material (delaminated) represents approximately 1.56 in 2, or 1.63% of the total assumed face surface area of all coupons. Table 3h5-4 of Reference 2 provides that there is 777.5 lbs of cold galvanizing compound that is assumed to fail (100%

failure) in each containment at CNP.

Based on the results of the testing performed, the minimum quantity of cold galvanizing compound that could be assumed to fail would be approximately 12.67 lbs. As a result of the testing, the assumed maximum failure, for margin considerations, is 5%, or approximately 39 lbs.

This reduction in quantity of failed cold galvanizing compound was not used as an input to strainer head loss testing, as described in Section 3.f of Reference 2. The results of this testing were used to inform the inputs used for the downstream effects wear evaluation described in Section 3.m of this response.

I&M Response to Information Item 3.b.4 The information provided in the Reference 2 response to Information Item 3.b.4 remains applicable.

to AEP-NRC-2008-17 Page 14 I&M Response to Information Item 3.b.5 I&M has completed removal of a significant quantity of labels, tags, signs, tape, and similar materials from the CNP Unit 1 and Unit/2 containments. I&M completed removal, to the extent practical, of these materials from Unit 1 during the Spring 2008 RFO. The currently established bounding values for the surface area of these materials are provided in Table 3b5-1 below, which is unchanged from that provided in Reference 2. The values, determined by walkdown and calculation, for unqualified labels for Unit 1 and Unit 2 have been added to the table to provide the margin that is available between the bounding values and the actual values.

Table 3b5-1 Bounding Quantity of Debris Available to Transport That Can Reduce Effective Strainer Area Debris Type Upper Loop Pipe Ice Containment Compartment Annulus Condenser Submerged Electromark Labels below Elevation 9.86 30.48 614 ft, ft2 Unqualified Labels, ft2 8.77 (bounding value)

Fire Barrier Tape Small Pieces (< 4 in), ft2 14.4 Fire Barrier Tape Large Pieces (> 4 in), ft2 54.1 Flexible Conduit PVC Jacketing, ft2 1.57 Ice Storage Bag Liner Shards, ft2 0.87 Pieces of Work Platform Rubber, ft2 0.22 Total, ft2 8.77 93.55 34.03 1.09 Unit 1 Specific Unqualified 3.23 5.62 3.46 Labels, ft2 3.2_5.2_346_

Unit 2 Specific Unqualified 1.75 5.43 2.40 Labels, ft2 1.75 5.43 2.40 to AEP-NRC-2008-17 Page 15 NRC Information Item 3.c - 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.

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 NRC-approved guidance.

I&M Response to NRC Information Item 3.c.

The information provided in the Reference 2 response to Information Item 3.c remains applicable.

NRC Information Item 3.d - 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.

I&M Response to Information Items 3.d.1, 3.d.2, and 3.d.3 The information provided in the Reference 2 response to Information Items 3.d.1, 3.d.2, and 3.d.3 remains applicable.

I&M Response to Information Item 3.d.4 The information provided for Information Item 3.d.4 in Reference 2, through Table 3d4-4, has been restated to provide the necessary background for a discussion of additional Unit 1 information.

The additional Unit 1 information is based on walkdowns performed during the Spring 2008 RFO. The additional Unit 1 information is presented following Table 3d4-4.

I&M has conservatively assigned 76 ft2 of the available surface area of the main strainer (900 ft2 total available) and 83 ft2 of the available surface area of the remote strainer (1072 ft2 total to AEP-NRC-2008-17 Page 16 available) for miscellaneous latent debris in containment. These sacrificial strainer areas were based on the area that was assumed to be blocked for large scale strainer testing (50 ft2 for the main, and 72 ft2 for the remote) as described in the response-to Information Item 3.f.4. Also contained in the response to Information Item 3.f.4 is the discussion of the additional sacrificial strainer area that was actually used during large scale testing as a result of not being able to test with a portion of a pocket. This resulted in an additional sacrificial strainer area of 26 ft2 for the main strainer and 11 ft2 for the remote strainer. In the response to Information Item 3.b.5, Table 3b5-1 provides the total bounding quantity of debris generated that could potentially block the main and remote strainers. With the debris transport fractions from Tables 3d4-1 and 3d4-2 applied to the debris generated, a bounding quantity of 34.75 ft2 of material is available for potential blockage of the main strainer, and 38.96 ft2 of material available for potential blockage of the remote strainer. Using the provisions of Section 3.5.2.2.2 of the SER, the assumed bounding effective strainer area blocked for the main strainer is (0.75)(34.75 ft2) := 26.06 ft2 and for the remote strainer is (0.75)(38.96 ft2) = 29.22 ft2. This provides margin for sacrificial strainer area of 50 ft2 for the main strainer and 54 ft2 for the remote strainer. Refer to Tables 3d4-1 and 3d4-2 for debris quantities expected to arrive at the main and remote strainers for both DEGB and DGBS.

Tables 3d4-1 and 3d4-2 are composite tables utilizing the worst case debris quantities from Unit 1 and Unit 2.

Table 3d4-1 Bounding Debris at Main Strainer for Sacrificial Strainer Area Consideration for DEGB and DGBS Type Debris Transport Debris at Debris Generated Fraction Strainer Electromark Labels (inside ZOI), ft2 0.7 0.13 0.091' Electromark Labels (outside ZOI), ft2 39.6 0.03 1.188 Unqualified Labels (.all of containment), ft" 25.94 0.86 22.308 Fire Barrier Tape Small 14.4 0.13 1.872 Pieces (< 4 in), ft2 Fire Barrier Tape Large Pieces (> 4 in), ft2 54.1 0.13 7.033 Flexible Conduit PVC Jacketing, ft2 1.57 1

1.57 Ice Storage Bag Liner 0.87 0.63 0.548 Shards, ft Pieces of Work Platform Rubber, ft2 0.22 0.63 0.139 Total, ft2 137.4 34.75 to AEP-NRC-2008-17

'Page 17 Table 3d4-2 Bounding Debris at Remote Strainer for Sacrificial Strainer Area Consideration for DEGB and DGBS Debris Type Debris Transport Debris at Generated Fraction Strainer Electromark Labels (inside ZOI), ft2 0.7 0.47 0.329 Electromark Labels (outside ZOI), ft2 39.6 0.69 27.324 Unqualified Labels (pall of containment), ftt 25.94 0.4 10.38 Fire Barrier Tape Small Pieces (< 4 in), ft2 14.4 0

0 Fire Barrier Tape Large Pieces (> 4 in), ft2 54.1 0

0 Flexible Conduit PVC Jacketing, ft2 1.57 0.3 0.471 Ice Storage Bag Liner 0.87 0.42 0.365 Shards, ft Pieces of Work Platform Rubber, ft2 0.22 0.42 0.092 Total, ft2 137.4 38.96 Based on data collection completed in Unit 2, Tables 3d4-3 and 3d4-4, below, provide the calculated quantities of debris for Unit 2 for the DEGB and DGBS that are considered for strainer sacrificial area, before applying the provisions of Section 3.5.2.2.2 of the SER. With the debris transport fractions from Tables 3d4-3 and 3d4-4 applied to the Unit 2 calculated quantity of debris, a quantity of 20.68 ft2 of material is available for potential blockage of the main strainer, and 32.41 ft2 of material available for potential blockage of the remote strainer. Using the provisions of Section 3.5.2.2.2 of the SER, the assumed effective Unit 2 strainer area blocked for the main strainer is (0.75)(20.68 ft2) = 15.51 ft2 and for the remote strainer is (0.75)(32.41 ft2) = 24.31 ft2.

to AEP-NRC-2008-17 Page 18 Table 3d4-3 Unit 2 Debris at Main Strainer for Sacrificial Strainer Area Consideration for DEGB and DGBS Debris Transport Debris at Debris Type Generated Fraction Strainer Electromark Labels (inside ZOI), ft2 0.7 0.13 0.091 Electromark Labels (outside ZOI), ft2 39.6 0.03 1.188 Unqualified Labels (all of containment), ft2 9.58 0.86 8.24 Fire Barrier Tape Small Pieces (< 4 in), ft2 14.4 0.13 1.872 Fire Barrier Tape Large 54.1 0.13 7.033 Pieces (> 4 in), ft2 Flexible Conduit PVC Jacketing, ft2 1.57 1

1.57 Ice Storage Bag Liner Shards, ft2 0.87 0.63 0.548 Pieces of Work Platform Rubber, ft2 0.22 0.63 0.139 Total, ft2 121.04 20.68 to AEP-NRC-2008-17 Page 19 Table 3d4-4 Unit 2 Debris at Remote Strainer for Sacrificial Strainer Area Consideration for DEGB and DGBS Debris Type Debris Transport Debris at Generated Fraction Strainer Electromark Labels (inside ZOI), ft2 0.7 0.47 0.329 Electromark Labels 39.6 0.69 27.324 (outside ZOI), ft2 39.6_0.69 27.324 Unqualified Labels (all of containment), ft2 9.58 0.4 3.83 Fire Barrier Tape Small Pieces (< 4 in), ft2 14.4 0

0 Fire Barrier Tape Large 54.1 0

0 Pieces (-> 4 in), ft2 Flexible Conduit PVC Jacketing, ft2 1.57 0.3 0.471 Ice Storage Bag Liner Shards, ft2 0.87 0.42 0.365 Pieces of Work Platform 0.092 Rubber, ft2 0.22

_0.42 Total, ft2 121.04 32.41 (Start of additional information for Unit 1)

Based on data collection completed in Unit 1, Tables A:N:2008-17-3d4-5 and A:N:2008-17-3d4-6, below, provide the calculated quantities of debris for'Unit 1 for the DEGB and DGBS that are considered for strainer sacrificial area, before applying the provisions of Section 3.5.2.2.2 of the SER. With the debris transport fractions from Tables A:N:2008-17-3d4-5 and A:N:2008-17-3d4-6 applied to the calculated Unit 1 debris quantity, 23.03 ft2 of material is available for potential blockage of the main strainer, and 33.50 ft2 of material is available for potential blockage of the remote strainer. Using the provisions of Section 3.5.2.2.2 of the SER, the assumed effective Unit 1 strainer area blocked for the main strainer is (0.75)(23.03 ft2) = 17.27 ft2 and for the remote strainer is (0.75)(33.50 ft2) = 25.13 ft2.

to AEP-NRC-2008-17 Page 20 Table A:N:2008-17-3d4-5 Unit I Debris at Main Strainer for Sacrificial Strainer Area Consideration for DEGB and DGBS Debris Transport Debris at Debris Type Generated Fraction Strainer Electromark Labels (inside ZOI), ft2 0.7 0.13 0.091 Electromark Labels (outside ZOI),

ft2 39.6 0.03 1.188 Unqualified Labels (all of containment), ft2 12.31 0.86 10.59 Fire Barrier Tape Small Pieces

(< 4 in), ft2 14.4 0.13 1.872 Fire Barrier Tape Large Pieces

(> 4 in), ft2 54.1 0.13 7.033 Flexible Conduit PVC Jacketing, ft2 1.57 1

1.57 Ice Storage Bag Liner Shards, ft2 0.87 0.63 0.548 Pieces of Work Platform Rubber, ft2 0.22 0.63 0.139 Total, ft2 123.77 23.03 Table A:N:2008-17-3d4-6 Unit I Debris at Remote Strainer for Sacrificial Strainer Area Consideration for DEGB and DGBS Debris Type Debris Transport Debris at Generated Fraction Strainer Electromark Labels (inside ZOI), ft2 0.7 0.47 0.329 Electromark Labels (outside ZOI),

ft2 39.6 0.69 27.324 Unqualified Labels (all of containment), ft2 12.31 0.4 4.92 Fire Barrier Tape Small Pieces

(< 4 in), ft2 14.4 0

0 Fire Barrier Tape Large Pieces

(> 4 in), ft2 54.1 0

0 Flexible Conduit PVC Jacketing, ft2 1.57 0.3 0.471 Ice Storage Bag Liner Shards, ft2 0.87 0.42 0.365 Pieces of Work Platform Rubber, ft2 0.22 0.42 0.092 Total, ft2 123.77 33.50 to AEP-NRC-2008-17 Page 21 NRC Information Item 3.e - 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

[DIs].

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.

I&M Response to Information Items 3.e The information provided in the Reference 2 response to Information Item 3.e remains applicable.

NRC Information Item 3.f - 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 (SBLOCA) and large-break loss-of-coolant accident (LBLOCA) 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.

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.

to AEP-NRC-2008-17 Page 22

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 temperature/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 strainer surface, and if so, summarize the methodology used to determine the available containment pressure.

I&M Response to Information Items 3.f.1 through 3.f.3, and 3.f.5 through 3.f.14 The information provided in the Reference 2 response to Information Item 3.f remains applicable for these information items.

I&M Response to Information Item 3.f.4 The following information is in addition to that provided in the Reference 2 response to Information Item 3.f.4.

Debris concentration analysis of water samples that were collected during debris only head loss testing at CCI was performed by ALION (Reference 10). These samples were collected after a stable head loss was achieved at 100% flow and 100% debris conditions. The samples were taken from a sample connection downstream of the test strainers in the pump discharge piping.

The estimated concentration in the test pool following completion of debris addition varied between about 4000 ppm for the DGBS tests and 6600 ppm for the DEGB tests. The results of this analysis are provided in Table A:N:2008-17-3.f.4.1, below.

The analysis results demonstrate the filtering capability of the CNP strainer system which provides significant conservatism to the assumptions used for debris quantities that would be resident in the systems downstream of the strainers and the time period foir which those quantities of debris are assumed to exist.

to AEP-NRC-2008-17 Page 23 Table A:N:2008-17-3.f.4-1 Sample Time From Final Sample Identification Test Description Debris Addition Concentration Identificatio

_hrs ppm T-2121-2 Standard (Homogeneous) DGBS 25 1.6 Head Loss Test T-2121-3 Standard (Homogeneous) DEGB 26 2.1 Head Loss Test T-2121-4 DGBS Debris Sequence Head Loss Test 2.5 89.8 T-2121-5 DEGB Debris Sequence Head Loss Test 2.3 198.6 T-2121-6 DGBS Event Sequence Head Loss Test 5.5 37.0 T-2121-7 DEGB Event Sequence Head Loss Test 3.8 125.8 NRC Information Item 3q - 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 LBLOCA and SBLOCAs.

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.

to AEP-NRC-2008-17 Page.24

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.

I&M Response to NRC Information Item 3.q.1 and 3.q.2 With the exception of the following information, the information provided in the Reference 2 response to Information Items 3.g.1 and 3.g.2 remains applicable.

Concurrent with the change in the design and licensing basis from a non-mechanistic 50%

blockage of the recirculation sump suction strainers to the mechanistic methodology required by GL 2004-02, the determination of the water level associated with NPSH was also changed.

Prior to the change in methodology, available NPSH for the pumps taking suction on the recirculation sump was determined based on a water level in containment of 602 ft 10 in, outside the recirculation sump.

As described in the response to Information Item 3.f in Reference 2, a decreasing water level inside the recirculation sump presents a greater challenge to the successful operation of the pumps taking suction on the recirculation sump.

The available NPSH for the RHR and CTS pumps is now determined by establishing the reference point for available water head at a water level of 601 ft 6 in inside the recirculation sump.

I&M Response to NRC Information Items 3.g.3 through 3.q.15 The information provided in the Reference 2 response to Information Item 3.g remains applicable for these information items.

I&M Response to NRC Information Item 3.q.16 Reference 2 Table 3g16-1 provided the NPSH margins for the RHR and CTS pumps which take suction from the recirculation sump.

Table A:N:2008-17-3g16-1, below, supersedes Reference 2 Table 3g16-1. The information in Table A:N:2008-17-3g16-1 reflects the change in reference point of the water head used in the determination of available NPSH.

Prior to the change in the design and licensing basis, the reference point was 602 ft 10 in water level in containment, outside the recirculation sump. The current design and licensing basis establishes the reference point at 601 ft 6 in inside the recirculation sump. The previous NPSH analysis assumed a head loss of approximately. 1 ft across the recirculation sump strainer. This resulted in a water level of 601 ft 10 in inside the recirculation sump. As a result of these changes, the NPSH margin for all cases has decreased by 4 in (0.3 ft), as reflected in the table.

to AEP-NRC-2008-17 Page 25 Table A:N:2008-17-3g16-1 NPSH Margins for RHR and CTS Pumps in Recirculation Mode Pump Flow NPSHa NPSHr Margin Unit 1 West RHR 4093 gpm 27.3 ftabs 16.6 ft abs 10.7 ft abs East RHR 4047 gpm 30.4 ft abs 16.3 ft abs 14.1 ft abs West CTS 3251 gpm 27.8 ft abs 14.0 ft abs 13.8 ft abs East CTS 3279 gpm 28.8 ft abs 14.1 ft abs 14.7 ft abs Unit 2 West RHR 4175 gpm 26.3 ft abs 17.1 ft abs 9.2 ft abs East RHR 4173 gpm 30.2 ft abs 17.0 ft abs 13.2 ft abs West CTS 3253 gpm 28.2 ft abs 14.0 ft abs 14.2 ft abs East CTS 3281 gpm 29.2 ft abs 14.1 ft abs 15.1 ft abs NRC Information Item 3.h - 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, Le., chips, particulate, size distribution and provide bases for the assumptions.

7. Describe any ongoing containment coating condition assessment program.

I&M Response to Information Item 3.h The information provided in the Reference 2 response to Information Item 3.h remains applicable.

NRC Information Item 3.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.

to AEP-NRC-2008-17 Page 26 Provide the information requested in GL 04-02 Requested Information 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, "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 (guidance 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 I&M Response to Information Items 3.i.1, 3.i.4, 3.i.5, 3.i.7, and 3.i.8 The information provided in the Reference 2 response to Information Item 3.i remains applicable for these information items.

to AEP-NRC-2008-17 Page 27 I&M Response to Information Item 3.i.2 The following information is in addition to that provided in the Reference 2 response to Information Item 3.i.2.

I&M has completed evaluating station programs and processes and has established the necessary controls to prevent the introduction of foreign material into containment that could challenge the recirculation function as required by the updated design and licensing basis.

The additional FME programmatic controls that have been implemented include:

" Changes to the station procedure that governs the issuance of maintenance permits to prohibit labels from being hung inside containment in Modes 1 - 4.

" Changes to the station procedure that provides for control of safety-related parts to require removal of the tracking tags upon installation inside containment.

Changes to the maintenance grouting procedure to prohibit the use of wet rags or plastic in containment in Modes 1 - 4.

Containment closeout and inspection procedures ensure that any such debris sources that may be used during Modes 5 and 6 are removed prior to ascending to Mode 4 during an outage.

I&M Response to Information Item 3.i.3 The following information is in addition to that provided in the Reference 2 response to Information Item 3.i.3.

I&M has revised the station procedure that is used to determine the applicable process for proposed changes to the plant to include consideration of changes that have the potential to impact the recirculation function and supporting analyses.

The new design and licensing basis associated with the mechanistic evaluation of the recirculation function was implemented on May 31, 2008, via UCR-1917 (Reference 11). The UFSAR (via Reference 11) now contains sufficient information to ensure changes to the facility will be evaluated in accordance with 10 CFR 50.59 requirements, including potential changes to programmatic and process controls that support and protect the recirculation function.

I&M Response to Information Item 3.i.6 The following information is in addition to that provided in the Reference 2 response to Information Item 3.i.6.

As provided in the Reference 2 response to Information Item 3.b.3, I&M performed destruction testing to qualify a double jacketing, increased banding configuration for the service water lines in the lower containment loop compartment that could be subjected to jet impingement. These lines are insulated with a foam insulation that is glued to the piping and itself and then jacketed with stainless steel jacketing that is banded in place. The pre-test configuration consisted of a to AEP-NRC-2008-17 Page 28 single-jacketed insulation with bands spaced at approximately 12 in intervals. The insulation on applicable service water lines in Unit 1 has been double jacketed with stainless steel jacketing with banding applied at intervals not to exceed six (6) in. This action was completed during the Unit 1 Spring 2008 RFO.

NRC Information Item 3.i - 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.

I&M Response to Information Item 3.j.1

The following information is in addition to that provided in the Reference 2 response to Information Item 3.j.1.

I&M has performed extensive plant modifications to support resolution of the GL 2004-02 concerns.

I&M has completed these changes in both Unit 1 and Unit 2.

During the Unit 1 Spring 2008 RFO, I&M completed installation of the remote strainer, flood-up overflow wall debris interceptor, annulus debris gate, and flood-up overflow flow wall openings and radiation shield modifications.

The description of the plant modifications is as described in the Reference 2 response to Information Item 3.j.1.

I&M Response to Information Item 3.J.2 The following information is in addition to that provided in the Reference 2 response to Information Item 3.j.2.

In Unit 1, I&M has performed the following plant modifications necessitated by installation of the remote strainer and waterway:

Relocation of a locked high radiation area gate Relocation of conduit pull boxes for pipe tunnel sump level switches.

Installation of a re-configured pipe tunnel sump cover.

Relocation of pipe tunnel sump level switches.

Relocation of pipe tunnel sump pumps.

Relocation of a Reactor Coolant Drain Tank relief valve line.

Partial removal of a pipe whip restraint.

Relocation of an accumulator drain line.

Relocation of a welding receptacle box.

Relocation of the RCS Loop 2 flow instrument manifold high and low side drains.

Relocation of plant grounding conductors.

to AEP-NRC-2008-17 Page 29 Removal of a type ABC fire extinguisher adjacent to the pipe tunnel sump.

Removal and capping off a segment of the previously disconnected stem packing leak off line.

9 Installation of a lateral support for the RHR line adjacent to the remote strainer waterway.

NRC Information Item 3.k - 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)(vii).

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.

I&M Response to Information Item 3.k.1 The following information is in addition to that provided in the Reference 2 response to Information Item 3.k.1.

A new remote strainer, described in the response to Reference 2 Information Item 3.j.1, has been installed in Unit 1 during the Spring 2008 RFO, utilizing the load cases described in the Reference 2 response to Information Item 3.k.1.

I&M Response to Information Item 3.k.2 The following information is in addition to that provided in the, Reference 2 response to Information Item 3.k.2.

The analyses for the Unit 1 remote strainer and waterway were performed with finite element analysis (using ANSYS and SAP methodologies) and static calculations.

The remote strainer for Unit 1 was analyzed by the strainer vendor, CCI, per Reference 12. The remote to AEP-NRC-2008-17P Page 30 strainer analysis performed for Unit 1 was the same as that performed for Unit 2 (bounding analysis). The waterway for Unit 1 was analyzed by S&L, per Reference 13.

Since the waterway layout for Unit 1 is essentially a mirror image of Unit 2, and the Unit 1 waterway was slightly redesigned based on lessons learned from Unit 2 resulting in a configuration that was less susceptible to high stresses as a result of thermal expansion, the resulting loads are comparable to, and in some cases, reduced from those determined for Unit 2 (Reference 14). In no case did the calculated load exceed the allowable load. In Reference 2, Table 3k2-5 provides the calculated stresses, allowable stresses, and interaction ratios.

Additionally, due to the redesign of the waterway, the flange connection.to the crane wall was eliminated, removing those load points that were provided in the Unit 2 table.

I&M Response to Information Items 3.k.3 and 3.k.4 The information provided in the Reference 2 response to Information Items 3.k.3 and 3.k.4 remains applicable for these information items.

NRC Information Item 3.1 - 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.

Provide a summary of the upstream effects evaluation including the information requested in GL 2004-02 Requested Information Item 2(d)(iv).

GL 2004-02 Requested Information Item 2(d)(iv).

The basis for concluding that the water inventory required to ensure adequate ECCS or CSS recirculation would not be held 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 has been evaluated, including likelihood of blockage and amount of expected holdup.

I&M Response to Information Item 3.1 The information provided in the Reference 2 response to Information Item 3.1 remains applicable.

to AEP-NRC-2008-17 Page 31 NRC Information Item 3.m - 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.

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 mesh spacing and state the basis for concluding that adverse gaps or breaches are not present on the screen surface.

GL 2004-02 Requested Information 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 NRC-approved methods were used (e.g., WCAP-16406-P with accompanying NRC SE), briefly summarize the application of the methods. Indicate where the approved methods were not used or exceptions were taken, and summarize the evaluation of those areas.

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.

I&M Response to Information Item 3.m.1 The following information is in addition to that provided in the Reference 2 response to Information Item 3.m.1.

I&M has completed evaluation of ex-vessel recirculation path blockage and wear from debris-laden fluid in accordance with WCAP-16406-P, Revision 1 (Reference 15), with the conditions and limitations of the NRC Safety Evaluation Report (Reference 16) considered. The wear evaluation was performed for I&M by S&L.

The evaluation of the potential for blockage in valves, orifices, heat exchangers, and instrumentation was provided in the Reference 2 response to Information Item 3.m.1.

The information contained within that response has not changed.

The pump wear evaluations considered both abrasive (free flow and packing) and erosive wear as described in Reference 15.

The pump wear evaluations also considered both hydraulic to AEP-NRC-2008-17 Page 32 effects and mechanical effects as a result of the wear evaluations. No exceptions were taken to the approved methodology or the conditions or limitations of References 15 and 16. For debris depletion consideration, no credit was taken for particulate debris filtration by the recirculation sump strainers or any other component within the recirculation flow path. The only particulate debris depletion method considered was the fraction of debris that could settle within the reactor vessel lower plenum. Fibrous debris depletion was considered to occur only on the first pass through the recirculation sump strainer.

A significant conservatism added to the pump wear evaluation was that the pumps were considered to be at their minimum operability limit for hydraulic verification at the start of recirculation, and used IST results to predict wear to the end of plant life and added the determined wear due to pumping debris-laden water for the pump mission time for mechanical verification.

As stated in the response to Information Item 3.b.3 in this attachment, the testing performed on cold galvanizing compound resulted in less than 2% of the compound failing. The downstream effects wear evaluation used a quantity of approximately 28.5% of the total (in containment) cold galvanizing compound that was assumed to pass through the recirculation sump strainers adding to the total debris fraction in the downstream fluid.

I&M Response to Information Item 3.m.2 The following information is in addition to that provided in the Reference 2 response to Information Item 3.m.2.

The evaluation described in the above response to Information Item 3.m.1 determined that the CC, RHR, and CTS pumps would function satisfactorily for the required 30 day mission time.

-The SI pumps were determined to be able to function satisfactorily, at their design flow rate, for a maximum of 15.4 days.

The limiting condition for the SI pumps was the conservatively determined wear that could result in mechanical (vibration) wear limits having been reached.

Based on CNP accident analysis requirements, the SI pumps are conservatively determined to be required for only the first 30 hours3.472222e-4 days 0.00833 hours 4.960317e-5 weeks 1.1415e-5 months following a LOCA.

The wear evaluation for other ex-vessel components determined that the installed throttle valves, heat exchangers, spray nozzles, and some of the installed orifices would have debris induced wear less than the guidance given in Reference 15. Some of the orifices installed in the systems were determined to wear in excess of the guidance.

To ensure that the necessary core and containment flow would be maintained after subjecting the pumps to the wear evaluations, pump curves were generated for each of the CNP pumps.

Additionally, to ensure pumps would not reach run-out conditions, an analysis (Reference 18) was performed of the systems that included the predicted wear of components within the flow paths integrated with the pump curves that were generated.

The results of this analysis determined that the necessary core and containment cooling would be maintained and that none of the pumps would reach a run-out condition based on system wear.

to AEP-NRC-2008-17 Page 33 The pump seals were also evaluated for the potential for failure due to pump operation with debris-laden fluid. This evaluation determined that for the design of seals installed on the CNP pumps, the seals would not fail, thus eliminating a potential common mode failure mechanism.

I&M Response to Information Item 3.m.3 The following information is in addition to that provided in the Reference 2 response to Information Item 3.m.3.

I&M has not made any design changes as a result of the ex-vessel wear evaluation that has been completed, and has determined that no physical changes are necessary.

I&M has enhanced the existing emergency operating procedures to provide guidance for the control room operators to request the Plant Evaluation Team in the Technical Support Center to consider removing unnecessary pumps from service to make them available for operation later in the event, if needed. The enhancement of this step in the procedures is consistent with the information previously contained in the ERGs.

NRC Information Item 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 NRC staff comments on that document. Briefly summarize the application of the methods. Indicate where the WCAP methods were not used or exceptions were taken, and summarize the evaluation of those areas.

I&M Response to Information Item 3.n.1 The following information is in addition to that provided in the Reference 2 response to Information Item 3.n.1.

I&M had Westinghouse perform an in-vessel evaluation of downstream effects per the guidance contained within WCAP-16793 (Reference 19) with consideration of NRC staff comments on that document, including the letter from the NRC to NEI (Reference 20). This evaluation is considered as the LOCADM evaluation.

I&M has also had Westinghouse perform an evaluation of the potential for fuel assembly bottom nozzle inlet blockage from fibrous debris.

to AEP-NRC-2008-17 Page 34 The results of the LOCADM evaluation are provided in Table A:N:2008-17-3n1-1, below.

Table A:N:2008-17-3n1-1 Results of All Cases Scale Total Total Max Clad Case Thickness Deposition Deposition Temperature Case

-inThickness Thickness (p~m)

(p~m)

(mils)

(0F)

Unit 1 (min sump volume) 151 443 17 365.71 Unit 1 (max sump 61 353 14 365.71 volume)

Unit 2 (min sump 122 414 16 358.10 volume)

Unit 2 (max sump 54 346 14 358.09 volume)

For the minimum sump water volume cases, LOCADM was also run with increased quantities of debris - in accordance with the "bump-up factor" methodology described in Reference 21. The "bump-up factor" had a negligible effect on both the total thickness and fuel cladding temperature.

The results of the fuel assembly bottom nozzle blockage determined that the fiber bed formed would be approximately 0.028 in thick, significantly less than the value assumed for formation of a thin bed, 0.125 in.

It should also be noted that the openings in the fuel assembly bottom nozzles for CNP are 5.66 mm (0.221 in) for Unit 1, and 4.83 mm (0.190 in) for Unit 2. The smallest of these openings, 4.83 mm is twice the size of the maximum recirculation sump strainer opening of 2.4 mm.

To determine the quantity of fiber that would pass through the strainer, a test was performed at CCI (Reference 22).

This test was performed in the MFTL using a strainer module that represented the main strainer only. The flow rate used for the test represented a plant flow rate of 9,720 gpm. This value represents the flow rate through the main strainer with this strainer 90% blocked (1.0% open area). The quantity of fiber that was determined to pass through the strainer was 1.16%. In addition to the latent debris fiber that is conservatively assumed to be resident in the CNP containments, the fiber contribution from Cal-Sil, Marinite, and Min-K was also included in the total fiber passing through the strainer. The total volume of fiber from all sources, available for capture by the fuel assembly bottom nozzles, was determined to be 0.228 ft3. This value considers the total quantity of fibers from all sources in containment that could pass through the main and remote strainers, as a function of the debris transport fractions and the bypass testing that was performed.

Based on the information provided above, it is reasonable to conclude that significant blockage of the fuel assembly bottom nozzles will not occur due to the size of the openings in relation to to AEP-NRC-2008-17 Page 35 the size of the debris that can pass through the strainers. Additionally, the deposition model demonstrates that the deposits on the fuel cladding will not result in unacceptable fuel clad temperatures or fuel clad deposition thickness.

NRC Information Item 3.o Chemical Effects I&M has restructured this section to include those items from the content guide (Reference 4) and the review guidance (Reference 23) to provide consecutively numbered sections and sub-sections.

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. Sufficient Clean Strainer Area a) 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.

3. Debris Bed Formation a) 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.

4. Plant Specific Materials and Buffers a) 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.

5. Approach to Determine Chemical Source Term a) Licensees should identify the vendor who performed plant-specific chemical effects testing.

to AEP-NRC-2008-17 Page 36

6.

WCAP Base Model a) For licensees proceeding from block 7 to diamond_10 in the Figure 1 flow chart, 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.

b) List the type (e.g., AIOOH) and amount of predicted plant-specific precipitates.

7. Solubility of Phosphates, Silicates and Al Alloys a) Licensees should clearly identify any refinements (plant-specific inputs) to the base WCAP-16530 model andjustify why the plant-specific refinement is valid.

b) For crediting inhibition of aluminum that is not submerged, licensees should provide the sdbstantiation 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 passivated.

c) 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 remains conservative when crediting solubility given that small amount of chemical precipitate can produce significant increases in head loss.

d) Licensees should list the type (e.g., AIOOH) and amount of predicted plant specific precipitates.

8.

Chemical Iniection into the Loop a) Licensees should provide the one-hour settled 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.

b) 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.

c) 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).

9. Pre-mix in Tank a) Licensees should discuss any exceptions taken to the procedure recommended for surrogate precipitate formation in WCAP-16530.

to AEP-NRC-2008-17 Page 37

10. Integrated Head Loss Test With Near-Field Settlement Credit a) Licensees should provide the one-hour or two-hour precipitate settlement values measured within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months of head loss testing.

b) Licensees should provide a best estimate of the amount of surrogate chemical debris that settles away from the strainer during the test.

11. Head Loss Testing Without Near Field Settlement a) 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.

b) 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 0.00667 hours 3.968254e-5 weeks 9.132e-6 months ).

12. Test Termination Criteria a) Provide the test termination criteria.

13. Data Analysis a) Licensees should provide a copy of the pressure drop curve(s) as a function of time for the testing of record.

b) Licensees should explain any extrapolation methods used for data analysis.

14. 30-day Integrated Head Loss Test a) 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.

b) Licensees should provide a copy of the pressure drop curve(s) as a function of time for the testing of record.

15. Data Analysis Bump Up Factor a) 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.

to AEP-NRC-2008-17 Page 38 I&M Response to Information Item 3.o.1 The following information is in addition to that provided in the Reference 2 response to Information Item 3.o.1.

The information related to the 30-Day Integrated Chemical Effects Test conducted at the Vuez facility is contained in the response to Information Items 3.o.14 and 3.o.15 below. This testing was performed for I&M by ALION.

I&M Response to Information Items 3.o.2 through 3.o.13 The information provided in the Reference 2 response to these Information Items remains applicable.

I&M Response to Information Item 3.o.14 In lieu of extracting a significant quantity of information from the ALION Vuez test report for CNP (Reference 24), the test report with those attachments that are not proprietary to ALION, or have been authorized by ALION to be released for public disclosure, is provided as Attachment 5 to this letter.

As described in the Reference 2 response to Information Item 3.o.15.a, the results of the CCI chemical effects test are being utilized to establish the design basis contribution of chemical effects to the overall recirculation sump strainer head loss. The results of the ALION Vuez 30-Day Integrated Chemical Effects Test determined that a head loss increase factor of 1.4 over the debris-only head loss was applicable. The head loss increase factor determined by testing at CCI was 1.53 for the equivalent test. I&M has further increased this factor to 1.7 times the previously factored debris-only head loss determined through testing and analysis, as described in the Reference 2 response to Information Items 3.f and 3.o. As can be seen from the test results, the head loss increase factors from the ALION Vuez and CCI chemical effects tests compared fairly reasonably. The ALION Vuez test demonstrates that there are conservatisms, and available margin, between analytically determined conditions (WCAP-1 6530 approach) and in-situ testing utilizing CNP-specific conditions and debris sources.

One of the other primary purposes for conducting the ALION Vuez 30-Day Integrated Chemical Effects Test was to determine the potential impact of potential organic materials and not previously considered debris sources that exist in containment on overall strainer head loss.

The ALION Vuez test, therefore, included ethylene glycol, RCP motor oil, grease, and iron oxide.

As stated in the test report (Attachment 5), specific analysis of the debris bed for presence of the organic materials was not performed.

The iron oxide contributed to overall head loss due to its particulate nature.

The quantity of ethylene glycol considered for the test was based on an evaluation performed of the worst case break location inside containment in the ice condenser refrigeration system.

The quantity of RCP motor oil considered for the test was based on a loss of oil from one RCP motor. Any failure of the RCP motor oil system is collected and directed to the oil collection tank to AEP-NRC-2008-17 Page 39 that is located in the loop compartment, mounted to the 598 ft 9-3/8 in elevation floor. This tank is vented to the containment atmosphere and would be fully submerged during the recirculation mode of operation. The open vent would allow for any oil in the tank to be released to the containment pool.

The quantity of grease considered for the test was based on an evaluation of the surface areas of the polar crane circumferential rail at the top of the crane wall, plus the trolley rails that span the space between the crane rail trucks. Not all of the considered surfaces would be covered with grease, so this was a very conservative determination.

For the glycol and RCP motor oil, neither of these are considered to exist or be created during a LOCA, but were included to ensure any failure that did occur within these systems would not result in an unanalyzed condition.

A portion of the iron oxide included in the test was established by considering that a percentage of the tightly adhering corrosion film that exists inside the ice condenser on support steel that is not coated could be released during the blowdown phase of the event. This steel is principally ASTM A588 steel, commonly known as COR-TEN or bridge steel, which is not required to be coated.

As stated above, a specific analysis of the debris bed was not performed to determine the potential interaction of the organic materials.

However, an individual representing I&M was present at the Vuez test facility for the start of the test and the conclusion of the test. Although not included within the report, the I&M individual's observations associated with these materials are provided in the following paragraphs at the request of the NRC RES Staff.

From direct observation during the test sequence, the following information in relation to the organic materials used during the testing were made.

Figures A:N:2008-17-3o14-1 and A:N:2008-17-3o14-2 below show the grease that was applied to a stainless steel coupon and the ethylene glycol and RCP motor oil that was added to the test tank. The grease coupon was suspended in the spray-only section of the test tank (see Figure A:N:2008-17-3o14-3), and the liquids were poured into the flowing test tank pool.

When the required amount of ethylene glycol was poured into the test tank pool, it was immediately diluted and absorbed into the solution. When the oil was poured into the testtank pool, it initially formed a film on the surface, but within a few seconds began to emulsify. In less than approximately one minute after addition, the oil was completely emulsified and had disappeared from view at the surface of the pool.

Figures A:N:2008-17-3o14-4 through A:N:2008-17-3o14-7 provide photographs taken in quick succession showing the emulsification of the oil on the pool surface. Due to the debris in the water, it was not possible to see if there was any visible indication of the oil in the water stream at the viewing window for the strainer cartridges. There was no indication of oil film on the viewing window. Observations over the next several hours did not identify any visible indications of oil.

to AEP-NRC-2008-17 Page 40 Figure A:N:2008-17-3o14-1: Test Coupon with Grease to AEP-NRC-2008-17 Page 41 Figure A:N:2008-17-3o14-3: Test Coupon with Grease Installed in Test Tank Prior to Test to AEP-NRC-2008-17 Page 42 Figure A:N:2008-17-3o14-4: Oil on Surface of Test Tank Water Shortly After Addition #1 F

2 to AEP-NRC-2008-17 Figure A:N:2008-17-3o14-6: Oil c Page 43 Surface of Test Tank Water Shortly After Addition #3 Figure A:N:2008-17-3o14-7: Oil on #4 to AEP-NRC-2008-17 Page 44 The I&M representative returned to the Vuez test facility for the end of the test.

Upon completion of the test sequence, the back panel of the test tank was removed, exposing the test coupons and surface of the test tank pool. Figure A:N:2008-17-3o14-8 shows the steel plate that the grease was applied to prior to the start of the test. This plate is shown suspended in the upper left quadrant of the picture. A closer examination of the plate determined that all of the grease had been removed during the test.

Observation of the test tank pool identified bubbles of petroleum based material on the pool surface along with a slight film. The petroleum material appeared to be coated with very fine debris from the test tank. The petroleum material was also visible on the galvanized steel panels, again covered by very fine debris.

These observations can be seen in Figures A:N:2008-17-3o14-9 and A:N:2008-17-3o14-10.

to AEP-NRC-2008-17 Page 45 Figure A:N:2008-17-3o14-9: End of Test Showing Oil on Water Surface and on Figure A:N:2008-17-3o14-10: End of Test Showing Oil on Water Surface and on Galvanized Steel Panels #2 to AEP-NRC-2008-17 Page 46 Figure A:N:2008-17-3o14-11 shows the surface of the water in the test tank, not directly above the test coupons. At this location, the petroleum product can be seen on the surface of the water with little or no other debris. It should be noted that the tank pool was not recirculating at this time and the water was being drained from the test tank.

During the draining of the tank, it was observed that what appeared to be bubbles on the surface of the galvanized steel test coupons was actually petroleum material captured on the coupon by a debris layer. When water level decreased sufficiently to allow the buoyancy of the petroleum material to break through the debris layer, the petroleum material would rise to the surface. In some cases, the petroleum material would bring part of the debris with it. Figures A:N:2008-17-3o14-12 through A:N:2008-17-3o14-15 show the galvanized steel panels in the tank during the draining evolution and removed from the tank, drying to obtain the post-test to AEP-NRC-2008-17 Page 47 weight. The other test coupons that were in the submerged portion of the test tank were observed to not have any petroleum material on them during the draining evolution and after having been removed from the test tank for drying. It was also noted that the location of the petroleum product on the galvanized steel test coupons was only on the upper quarter of the plates. An exact cause for the formation of the petroleum bubbles on the upper sections of the galvanized test coupons was not established.

Figure A:N:2008-17-3o14-12: End of Test Showing Petroleum Locations (I*n rnlvnni-yarl Rfol Pnnn~lafi1 to AEP-NRC-2008-17 Page 48 Figure A:N:2008-17-3o14-13: End of Test Showing Petroleum Locations (n (Ivnni7AI RPAI Pi*no_

fi2 Figure A:N:2008-17-3o14-14: End of Test Showing Petroleum Locations On Galvanized Steel Panels #3 to AEP-NRC-2008-17 Page 49 Figure A:N:2008-17-3o14-15: End of Test Showing Petroleum Locations On Galvanized Steel Panels #4 Following the completion of draining, the test strainer section was removed from the tank.

Consistent with the draining of the tank that resulted with the water level dropping below the strainer pockets, there was some evidence of a slight petroleum material sheen on the surface of the debris bed inside the pockets. Figures A:N:2008-17-3o14-16 and A:N:2008-17-3o14-17 to AEP-NRC-2008-17 Page 50 show the debris bed after removal from the test tank. As can be seen in the photographs, some of the debris bed was dislodged during the removal process. The slight sheen is not readily seen in the photographs.

to AEP-NRC-2008-17 Page 51 Based on observations by the I&M representative, it did not appear that the organic materials impacted the test results and should not have an impact on the recirculation function if they were to be present during an actual event.

I&M Response to Information Item 3.o.15.a The information provided in the following paragraphs supplements the information provided in Reference 2.

The results of the ALION Vuez 30-Day Integrated Chemical Effects Test have been provided in the response to Information Item 3.o.14. The results of that testing indicated an increase in strainer head loss by a factor of 1.4 (bump-up factor) due to chemical effects. As described in the Reference 2 response to Information Item 3.o.15.a, I&M has established a design basis bump-up factor of 1.7 above the factored strainer system head loss that is based on the results of the large scale testing performed at CCI (refer also to the response to Information Item 3.p in this attachment). The results of the ALION testing demonstrate that there is margin between a WCAP-16530 approach and a more prototypical approach for the determination of the impact of chemical effects on strainer head loss.

to AEP-NRC-2008-17 Page 52 As stated in the Reference 2 response to Information Items 3.f and 3.o, the tested configuration for both the large scale tests and the chemical effects tests could only be performed on representative portions of the installed strainer configuration. The ALION test also could only be performed on a representative portion of the installed strainer configuration.

The representativeness of that testing is provided in the test report and supporting information contained in Attachment 5.

NRC Information Item 3.p - 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. 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.

GL 2004-02 Requested Information Item 2(e)

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 GL.,Any licensing actions or exemption requests needed to support changes to the plant licensing basis should be included.

I&M Response to Information Item 3.p The following information is in addition to that provided in the Reference 2 response to Information Item 3.p.

UFSAR Changes Associated With Plant Modifications Changes to UFSAR Section 6.2, Section 6.3, Figure 6.2-1A, and Figure 9.3-1, to reflect installation of a new remote strainer in Unit 1 were made effective on the date that the associated systems were returned to operations following installation, April 29, 2008.

UFSAR Section 7.8, "Post Accident Monitoring," was changed to reflect the RG 1.97 classification of the new level switches which were installed inside the recirculation sump for Unit 1.

The UFSAR was changed following implementation of associated TS changes described below.

TS Changes The Reference 2 response to Information Item 3.p described the license amendment for changes to the TS to support the resolution of concerns identified in GL 2004-02, and stated to AEP-NRC-2008-17 Page 53 that those TS changes had been implemented for Unit 2. The TS changes were implemented for Unit 1 at the start of the Spring 2008 RFO.

Licensing Basis Changes Associated with Mechanistic Evaluation The UFSAR changes associated with the mechanistic evaluation of the effect of post-accident debris on the ECCS and CTS recirculation function as described in Reference 2 and this letter have been implemented. The associated 50.59 evaluation was approved on May 30, 2008,'and the UFSAR change was made effective on May 31, 2008. During the process of updating the UFSAR, administrative changes were also made to provide clarification and to renumber sections as a result of the new information. These administrative changes are not included in the following descriptions.

The portions of the UFSAR identified below were modified to reflect the mechanistic evaluation:

Section 1.4.7 - Engineered Safety Features (PSDC 37 - PSDC 65)

Unit 1 Section 3.5.4.1 - Design Basis (Upgrade) [Fuel]

Unit 2 Section 3.4.1.5 - Other Considerations [Fuel]

Section 6.1 - Application of ESF Design Criteria Section 6.2.2 - System Design and Operation [ECCS]

Section 6.2.4 - Safety Limits and Conditions [ECCS]

Section 6.2.6 - Programmatic Controls [ECCS]

Section 6.3.2 - System Design [CTS]

Table 6.1 Net Positive Suction Heads for Post-DBA Operational Pumps Table 6.2 Safety Injection System Code Requirements New Table 6.2 Recirculation Sump Design Load Combinations Section 7.5.2 - System Design [ESF Instrumentation]

Unit 1 - Section 14.3 - Reactor Coolant System Pipe Rupture (Loss of Coolant Accident)

UFSAR Unit 2 Section 14.3 -

Reactor Coolant System Pipe Rupture (Loss of Coolant Accident)

UFSAR Unit 1 Section 14.3.9 -

was re-titled as "Containment and Recirculation Sump Analyses" and revised to include the sub-sections listed below.

This Unit 1 Section is referenced by UFSAR Unit 2 Section 14.3.9.

14.3.9 - Containment and Recirculation Sump Analyses 14.3.9.1 -Accidents Leading to Sump Recirculation 14.3.9.2 - Accident Description - General System Performance 14.3.9.3 - Containment Sump Inventory Analysis 14.3.9.4 - Recirculation Sump Analyses 14.3.9.4.1 - Debris Generation 14.3.9.4.1.1 - Break Selection 14.3.9.4.1.2 - Debris Sources 14.3.9.4.1.3 - Results 14.3.9.4.2 - Debris Transport 14.3.9.4.2.1 - Computer Code Utilized 14.3.9.4.2.2 - Method of Analysis to AEP-NRC-2008-17 Page 54 14.3.9.4.2.3 - Results 14.3.9.4.3 - Recirculation Sump Hydraulic Analysis 14.3.9.4.3.1 - Computer Code Utilized 14.3.9.4.3.2 - Method of Analysis 14.3.9.4.3.3 - Results 14.3.9.5 - Recirculation Sump Strainer Head Loss 14.3.9.5.1 - Recirculation Sump Strainer Debris Only Testing 14.3.9.5.2 - Recirculation Sump Strainer Chemical Effects Testing 14.3.9.5.3 - System Head Loss Determination 14.3.9.5.3.1 - Method of Analysis 14.3.9.5.3.2 - System Head Loss Results 14.3.9.6 - Design Considerations for Upstream and Downstream Effects 14.3.9.6.1 - Upstream Effects 14.3.9.6.2 - Downstream Effects 14.3.9.6.2.1 - Method of Analysis 14.3.9.6.2.2 - Assumptions 14.3.9.6.2.3 -Acceptance Criteria 14.3.9.6.2.4 - Results 14.3.9.6.2.5 - Conclusions 14.3.9.7 - References for 14.3.9 The following new tables were added to UFSAR Unit 1 Section 14.3.9:

14.3.9 Bounding Insulation Quantities by Potential Break Location 14.3.9 DEGB Coatings Debris Generated Within ZOI 14.3.9 DGBS Coatings Debris Generated Within ZOI 14.3.9 Unqualified Coatings Debris Generated Outside ZOI 14.3.9 Latent Debris Location Unit 1 and Unit 2 Bounding Values 14.3.9 Containment Materials 14.3.9 Maximum ECCS/CTS Flow Rates 14.3.9 Loop 4 RCS Crossover Leg Break (DEGB) Debris Loads at the Main and Remote Strainer 14.3.9 Loop 4 Alternate RCS Loop Piping Break (DGBS) Debris Loads at the Main Strainer and Remote Strainer 14.3.9 Quantity of Debris at Main Strainer for Large Scale Testing for DEGB and DGBS 14.3.9 Quantity of Debris at Remote Strainer for Large Scale Testing for DEGB and DGBS 14.3.9 Debris Quantities for MFTL Head Loss Tests 14.3.9 Chemical Quantities for DEGB Chemical Effects Testing 14.3.9 Chemical Quantities for DGBS Chemical Effects Testing 14.3.9 Vuez Chemical Effects Testing Debris Quantities 14.3.9 Vuez Chemical Effects Testing Material Quantities Submerged in Containment Sump 14.3.9 Vuez Chemical Effects Testing Non-Submerged Material Quantities 14.3.9 Strainer Minimum Submergence Determination 14.3.9 In-Vessel Fuel Rod Debris Deposition to AEP-NRC-2008-17 Page 55 14.3.9 Bounding Debris at Main Strainer for Sacrificial Strainer Area Consideration for DEGB and DGBS 14.3.9 Bounding Debris at Remote Strainer for Sacrificial Strainer Area Consideration for DEGB and DGBS The following new figures were added to UFSAR Unit 1 Section 14.3.9:

Figure 14.3.9 Recirculation Sump General Arrangement Figure 14.3.9-14 Sheet 1 - Predicted Flow Split Through Main Strainer Figure 14.3.9-14 Sheet 2 -

Strainer System Head Loss as Function of Main Strainer Blockage Figure 14.3.9 DEGB Head Loss Test Results Figure 14.3.9 DEGB Event Sequence Head Loss Test Results Figure 14.3.9 DEGB Debris Sequence Head Loss Test Results Figure 14.3.9 DGBS Head Loss Test Results Figure 14.3.9 DGBS Event Sequence Head Loss Test Results Figure 14.3.9 DGBS Debris Sequence Head Loss Test Results Figure 14.3.9 DEGB MFTL Chemical Effects Head Loss Test Results Figure 14.3.9 DGBS MFTL Chemical Effects Head Loss Test Results Figure 14.3.9-23 Sheets 1 & 2 - 30 Day Chemical Effects Head Loss Testing Pressure Drop Time History Figure 14.3.9 ECCS Recirculation Flow Path Figure 14.3.9 CTS Recirculation Flow Path NRC Information Item 3 - Conclusions The following information is in addition to that provided in the Reference 2 response to Information Item 3 - Conclusions.

I&M has completed analysis of in-vessel and ex-vessel downstream effects.

Based on the conservatisms and margins provided below, I&M considers that in the event of a LOCA the recirculation function would provide the necessary core and containment cooling. The primary basis for this consideration is the conservative assumption that a significant portion of the debris capable of passing through the strainers is assumed to transport to, and pass through, the strainers. Information was provided in the response to Information Item 3.f.4 in this attachment that demonstrates that a significant portion of the debris would be captured by the strainers.

This is further supported by the information provided in the Reference 2 response to Information Item 3.f which identifies the increase in head loss that would occur upon introduction of the debris. Since the head loss would increase significantly, and CNP has a very small quantity of fibrous material other than that assumed to exist as latent debris (see the Reference 2 response to Information Item 3.d), it can be assumed that the majority of the head loss would occur as a result of the particulate capture by the strainers. This capture would reduce the quantity of material available to impact downstream components. Also, as part of the downstream effects analyses, the quantity of cold galvanizing compound assumed to be generated and pass to AEP-NRC-2008-17 Page 56 through the strainers is significantly greater than the quantity determined to fail through DBA testing.

Conservatisms and Margins A description of the conservatisms and margins for each aspect of the resolution of GL 2004-02 are provided in the Reference 2 response to Information Item 3 -" Conclusions, and in the discussions below. Additional discussions of these conservatisms and margins are provided in the responses to the indicated information items in this attachment.

Debris Generation (Information Item 3.b)

I&M conservatively assumed that 100% of all cold galvanizing compound would fail by the initiation of recirculation following a LOCA. This is conservative with respect to the results of the DBA testing performed at K&L which documented less than 2% failure of the cold galvanizing compound.

I&M conservatively assumed a bounding quantity of unqualified labels in the Unit 1 and Unit 2 containments of 25.94 ft2.

The documented quantity of unqualified labels was 12.31 ft2 for Unit 1, and 9.58 ft2 for Unit 2.

Downstream Effects - Components and Systems (Information Item 3.m)

I&M conservatively assumed that approximately 28.5% of the total cold galvanizing compound in containment would pass through the strainers and potentially impact the downstream components. The testing of the cold galvanizing compound described in the response to Information Item 3.b in this attachment determined that less than 2% of the total could fail. Conservatively assuming that 5% could fail results in a margin of

(.285

777.5) - (.05

777.5) = 182.7 lbs of particulate. This represents a significant reduction in the downstream effects source term.

Chemical Effects (Information Item 3.o)'

The ALION Vuez 30-Day Integrated Chemical Effects Test determined that for CNP containment materials, the potential increase in head loss as a result of chemical effects could be as high as a factor of 1.4. This value is below the assumed design basis value of 1.7, and below the maximum increase factor of 1.53 determined by the CCI testing.

ATTACHMENT 4 TO AEP-NRC-2008-17 RESPONSES TO NRC REQUEST FOR ADDITIONAL INFORMATION Unless otherwise noted, the sections referenced are from Attachment 3.

The information provided in Attachment 6 to Reference 2 remains applicable except for the following responses to RAI questions 10, 11, and 33.

No.

GL 2004-02 RAI Questions GL 2004-02 RAI Responses Plant-Specific Chemical Effects If bench-top testing is being used to inform plant specific head loss This information is provided in the response to testing, indicate how the bench-top test parameters (e.g., buffering agent Information Item 3.0, and in the response to concentrations, pH, materials, etc.) compare to your plant conditions.

information Item 3.o in the Reference 2 response.

Describe your plans for addressing uncertainties related to head loss

10.

from chemical effects including, but not limited to, use of chemical surrogates, scaling of sample size and test durations. Discuss how it will be determined that allowances made for chemical effects are conservative.

Plant Environment Specific Provide a detailed description of any testing that has been or will be This information is provided in the response to performed as part of a plant-specific chemical effects assessment.

Information Item 3.o, and in the response to Identify the vendor, if applicable, that will be performing the testing.

Information Item 3.o in the Reference 2 response.

Identify the environment (e.g., borated water at pH 9, deionized water, tap water) and test temperature for any plant-specific head loss or transport tests. Discuss how any differences between these test 11 environments and your plant containment pool conditions could affect the behavior of chemical surrogates. Discuss the criteria that will be used to demonstrate that chemical surrogates produced for testing (e.g., head loss, flume) behave in a similar manner physically and chemically as in the ICET environment and plant containment pool environment.

to AEP-NRC-2008-17 Page 2 No.

GL 2004-02 RAI Questions GL 2004-02 RAI Responses Plant Specific You indicated that you would be evaluating downstream effects in This information is provided in the response to accordance with WCAP 16406-P. The NRC is currently involved in Information Items 3.m and 3.n.

discussions with the Westinghouse Owner's Group (WOG) to address questions/concerns regarding this WCAP on a generic basis, and some of these discussions may resolve issues related to your particular station.

The following issues have the potential for generic resolution; however, if a generic resolution cannot be obtained, plant-specific resolution will be required. As such, formal RAIs will not be issued on these topics at this time, but may be needed in the future. It is expected that your final evaluation response will specifically address those portions of the WCAP used, their applicability, and exceptions taken to the WCAP. For your information, topics under ongoing discussion include:

33a

a. Wear rates of pump-wetted materials and the effect of wear on 33a component operation

b. Settling of debris in low flow areas downstream of the strainer or credit for filtering leading to a change in fluid composition 33c

c. Volume of debris injected into the reactor vessel and core region 33d

d. Debris types and properties 33e

e. Contribution of in-vessel velocity profile to the formation of a debris bed or clog 33f

f. Fluid and metal component temperature impact 33g

g. Gravitational and temperature gradients 33h

h. Debris and boron precipitation effects 33i

i. ECCS injection paths

_33j

j.

Core bypass design features 33k

k. Radiation and chemical considerations 331 L Debris adhesion to solid surfaces 33m

m. Thermodynamic properties of coolant

v t e Letter Sequence Request
TAC:MC4679, (Open)
Initiation Request, Request, Request, Request, Request, Request, Request Acceptance... Supplement Administration Meeting, Meeting Questions 18 March 2009 18 March 2009 3 April 2009 13 May 2009 26 August 2009 25 August 2009 13 May 2010 18 June 2009 8 July 2009 24 July 2009 31 July 2009 13 August 2009 31 August 2009 16 September 2009 9 September 2009 20 November 2009 Answers Results Approval... Other: ML060370547, ML061860257, ML062020768, ML101960128
MONTHYEAR2009-05-13 [Table View]

AEP-NRC-2008-17, Final Response to NRC Generic Letter 2004-02: Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized Water Reactors and Associated Request for Additional Information

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AEP-NRC-2008-17, Final Response to NRC Generic Letter 2004-02: Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized Water Reactors and Associated Request for Additional Information

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