Text

AEP:NRC:8054-02, Attachment 3, I&M Response to Information Item 3.f.4, to NRC Information Item 3 - Conclusions.
	ML080770396
Person / Time
Site:	Cook
Issue date:	02/29/2008
From:	; Indiana Michigan Power Co
To:	; Office of Nuclear Reactor Regulation
References
	GL-04-002 AEP:NRC:8054-02
	Download: ML080770396 (135)
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Attachment 3 to AEP:NRC:8054-02 Page 181 I&M Response to Information Item 3.f.4 I&M used the ECCS sump strainer supplier, CCI, to perform CNP-specific strainer head loss testing. Two different test loop configurations were used for head loss testing during the strainer qualification program:* Multi Functional Test Loop at CCI's facility in Winterthur, Switzerland, using a one-sided strainer array and horizontal flow for chemical effects head loss testing. A description of the testing using the MFTL is provided in the response to Information Item 3.o.1.* Large scale tank testing in Winterthur, Switzerland, using a two-sided strainer array and horizontal flow. The large scale tank testing is described below.Larqe Scale Test Loop The Large Scale Test Loop contained a two-sided strainer array with three CCI strainer cartridges, per side, with 60 pockets per side. The array was placed in a water-filled pool. The strainer cartridges were the same design (dimpled pockets) that are installed in the CNP Unit 2 remote strainer and will be installed in the Unit 1 remote strainer during the Spring 2008 refueling outage. The strainer cartridges are two columns wide by ten rows high. Walls were erected in the test tank, around the strainer module, to simulate the main and remote strainer configuration at CNP. See Figure 3f4-1, below, for a sketch showing a plan view of the test pool configuration.

Figure 3f4-1 CCI Large Scale Test Configuration for CNP Testing I- r Attachment 3 to AEP:NRC:8054-02 Page 182 As shown in Figure 3f4-1, the test configuration provided for separate strainer areas to facilitate debris additions to the main and remote strainer in the quantities determined by the output of the debris generation (Reference

26) and debris transport (Reference

28) calculations.

The test configuration also provided the ability to determine nominal percentage of flow to each of the strainer areas. The area called "Recirc Flow Path" in Figure 3f4-1, was constructed as shown in the sketch showing an elevation view provided in Figure 3f4-2, below.Figure 3f4-2 Outline of Flow Window Location and Numbering Looking from Strainer Towards Sparger Pipe Eli 1 Remote Main rI 4 D] 2 Dý 5 D3D I IT I1 The flow openings provided for the use of a propeller type flow measuring device to determine the approximate flow distribution to each side of the strainer.

These measurements were taken after stable head loss conditions were achieved for 100% debris, 100% flow.The large scale test loop was equipped with a pump that had a flow capability of 100 m 3/h.Testing was conducted with the 100% plant flow rate scaled to 80 m 3/h to allow for testing above the nominal 100% plant flow rate value. The test loop contained instrumentation to determine flow rate, head loss (differential pressure), temperature, turbidity, and pump speed.The test configuration differed from the CNP installation in that there was not a waterway in series with the remote strainer, and the outlet from the test strainer was not vented. The response to Information Item 3.f.10 includes a discussion of the analysis that provided the correlation between the tested configuration and the plant configuration.

Attachment 3 to AEP:NRC:8054-02 Page 183 The large scale test facility was used by I&M to perform testing in late 2005 and in late Summer of 2007. The testing performed in 2005 was used to validate the design proposed for CNP.The testing performed in 2007 was used to establish bounding head loss values for the debris source term that had been updated since the 2005 testing.Strainer Pockets Figure 3f4-3, below, provides an illustration of a CCI strainer cartridge pocket. This illustration does not show the dimples in the four perforated faces of the pocket for the CNP design. The dimension markers (A, B, and C) on this illustration are used in the discussion of scaling for both the Large Scale Test Loop and MFTL testing.Figure 3f4-3 Basic Construction of a CCI Strainer Cartridge Pocket Scaling The scaling for the large scale test was evaluated for both test loop pump capacity and available strainer area. Figures 3f4-4 through 3f4-6, below, show the scaling factor determinations for each of these parameters.

Attachment 3 to AEP:NRC:8054-02 Page 184 Figure 3f4-4 Scaling Factor Based on Pump Capacity Flow Rate Flow Rate INPUT WPM) (m^3/h)DC Cook Pump Capacity 14400 3273 Test Pump Capacity 440 100 100% Scaled Flow Desired 352 80 IOUTPUT 1 Resultant

% flow (at max test pump capacity) 125%Scaling Factor (Max Pump Capacity) 41 Figure 3f4-5 Scaling Factor Based on Available "Main Strainer" Area INPUTS PROPOSED POCKETS TEST POCKETS Units mm inch mm inch A 109 4.29 109 4.29 B 70 2.76 70 2.76 C 288 11.34 288 11.34 Radius= A/2 54.5 2.15 54.5 2.15 Filtering Surfaces of a Pocket, Units mm2 in2 mm2 in2 1 Bent Plate 52305 81.07 52305 81.07 2 Flat Plates 72115 111.78 72115 111.78 Total Area / Pocket 124420 192.85 124420 .192.85_ _ _ _ _ _ _ _ _ I_ _ _ _ I_ _ _ _I___ I_ _ _ I SNumber of Pockets 1 1 I I (Main Strainer) for RMVI 672 672 60 60 Total Pocket Filtering Surface 83610240 129596 7465200 11571_ _ _ _ _ _ _ _ _ _ _ _ I II I_ _ _RESULTS m2 ft2 m2 ft2 Upper Cartridge Cover 0 0.00 0 0.00 Front Side Covers 0 0.00 0 0.00 Overall Total Area 83.61 899.97 7.47 80.35 Reduction (Tapes, Tags &Stickers) 4.65 50.00 0 0.00 Effective Resultant Area 78.96 849.97 7.47 80.35 Scaling Factor (Main Strainers) 11 Attachment 3 to AEP:NRC:8054-02.Page 185 Figure 3f4-6 Scaling Factor Based on Available "Remote Strainer" Area I Number of Pockets (Remote Strainer) 800 800 60 60 Total Pocket Filtering Surface 99536000 154281 7465200 11571 RESULTS m2 ft2 m2 ft2 Upper Cartridge Cover 0 0.00 0 0.00 Front Side Covers 0 0.00 0 0.00 Overall Total Area 99.54 1071.40 7A47 80.35 Reduction (Tapes, Tags &Stickers) 6.64 71.40 0 0.00 Effective Resultant Area 92.90 1000.00 7.47 80.35 4, ... .. ..Scaling Factor (Remote Strainer)12 Based on the evaluation of the scaling factor determinations, the scaling factor used for testing was 41 as a result of the flow rate limitations of the test loop pump. The available number of test strainer pockets required to support this testing were then determined using this scaling factor. The resulting numbers of test strainer pockets used are shown in Figure 3f4-7, below.Figure 3f4-7 Determination of Test Strainer Pockets Based on Scaling Factor INPUT Pockets ftA2 2 Main Strainer (installation) 635 850.41 Remote Strainer (installation) 747 J 1000.41 Scaling Factor (pump limited) F-41 OUTPUT (based on scaling factor) Pockets ftA2"Main" side of test unit 15.49 20.74 used: 15 pockets"Remote" side of test unit "18.22 24.40 used: 18 pockets The actual strainer configuration installed at CNP has a main strainer with approximately 900 ft 2 of strainer surface area, and a remote strainer with approximately 1072 ft 2 of strainer surface area. The values shown in Figure 3f4-7 account for the assumed sacrificial strainer area of 50 ft 2 for the main strainer and 72 ft 2 for the remote strainer.

For the main strainer, the number of pockets used for the testing (15), provided an additional margin of approximately 26 ft 2 of sacrificial strainer area. For the remote strainer, the number of pockets used for the testing (18), provided an additional margin of approximately 11 ft 2 of sacrificial strainer area.To provide for this reduced strainer area, panels with cutouts were placed over the face of the strainers to allow water and debris to enter only the number of pockets specified in Figure 3f4-7.Figure 3f4-8 provides a photograph of the strainer faces covered with the cutout panels.

Attachment 3 to AEP:NRC:8054-02 Page 186 Figure 3f4-8 Strainer Faces Covered to Provide Reduced Strainer Surface Area"Remote" Strainer "Main" Strainer The debris quantities were also scaled based on the scaling factor of 41. The debris that were used for testing are provided in Tables 3f4-1 through 3f4-3 below.Table 3f4-1 Quantity of Debris at Main Strainer Following Pool Fill quantities of for DEGB and DGBS Test Test Debris Type Units DEGB DGBS Quat Quantity Quantity RMI ft 2 5270.07 128.54 2836.07 69.17 Cal-Sil Fines lbs 89.568 2.18 23.2 0.57 Marinite I Fines lbs 0.0448 0.001 0 0 Marinite 36 Fines Ibs 0.3456 0.01 0.2528 0.01 Min-K lbs 0.512 0.01 0 0 Epoxy Paint (inside ZOI) lbs 68.576 1.67 1.28 0.03 Alkyd Paint (inside ZOI) lbs 0.192 0.005 0.192 0 Unqualified OEM Epoxy (outside ZOI) lbs 0 0 0 0 Unqualified OEM Alkyd (outside ZOI) lbs 0 0 0 0 Unqualified Non-OEM Epoxy (outside ZOI) lbs 0 0 0 0 Unqualified Non-OEM Alkyd (outside ZOI) lbs 0 0 0 0 Unqualified Cold Galvanizing Compound lbs 0 0 0 0 Dirt/Dust lbs 76.5 1.87 76.5 1.87 Latent Fiber ft 3 5.625 0.137 5.625 0.137 Fire Proof Tape Fines ft 3 0.0192 0.0005 0.0192 0.0005 Ice Storage Bag Fibers ft 3 0.0117 0.0003 0.0117 0.0003 Attachment 3 to AEP:NRC:8054-02 Page 187 Test DGS euatit Debris Type Units DEGB ati DGBS T Quantity Quantity Ice Storage Bag Liner Shards ft 3 0.000099 0.0000 0.000099 0.0000 Pieces of Work Platform Rubber ft 3 0.0009 0.0000 0.0009 0.0000 Fire Proof Tape Pieces (1) ft 3 0.0588 0.0014 0.0588 0.0014 Electromark Label (inside ZOI) (') ft 2 0.0602 0.0015 0.0602 0.0015 Electromark Label (outside ZOI) (1) ft 2 0 0 0 0 Unqualified Labels (1) ft 2 0 0 0 0 Flex Conduit PVC Jacketing (1) ft 2 0 0 0 0 (1) These debris materials were included in the sacrificial strainer area.Table 3f4-2 Quantity of Debris atMain Strainer (Total) During Recirculation for DEGB and DGBS Test Test Debris Type Units DEGB Quantity DGBS Quantity RMI ft 2 9064.52 221.09 4878.04 118.98 Cal-Sil Fines Ibs 143.557 3.50 35.815 0.87 Marinite I Fines Ibs 0.0974 0.002 0 0 Marinite 36 Fines Ibs 0.8028 0.02 0.5965 0.01 Min-K Ibs 0.688 0.02 0 0 Epoxy Paint (inside ZOI) Ibs 92.149 2.25 1.72 0.04 Alkyd Paint (inside ZOI) Ibs 0.258 0.01 0.258 0.00 Unqualified OEM Epoxy (outside ZOI) Ibs 7.04 0.17 7.04 0.17 Unqualified OEM Alkyd (outside ZOI) Ibs 10.556 0.26 10.556 0.26 Unqualified Non-OEM Epoxy (outside ZOI) Ibs 8.32 0.20 8.32 0.20 Unqualified Non-OEM Alkyd (outside ZOI) Ibs 2.088 0.05 2.088 0.05 Unqualified Cold Galvanizing Compound Ibs 723.075 17.64 723.075 18 Dirt/Dust Ibs 105.4 2.57 105.4 2.57 Latent Fiber ft 3 7.75 0.19 7.75 0.19 Fire Proof Tape Fines ft 3 0.0258 0.001 0:0258 0.001 Ice Storage Bag Fibers ft 3 0.01612 0.0004 0.01612 0.0004 Ice Storage Bag Liner Shards ft 3 0.000136 0.0000 0.000136 0.0000 Pieces of Work Platform Rubber ft 3 0.00124 0.0000 0.00124 0.0000 Fire Proof Tape Pieces (1) ft 3 0.1008 0.002 0.1008 0.002 Electromark Label (inside ZOI) ft 2 0.1032 0.003 0.1032 0.003 Electromark Label (outside ZOI) (W) ft 2 3.047 0.07 3.047 0.07 Unqualified Labels (1) ft 2 24.9024 0.61 24.9024 0.61 Flex Conduit PVC Jacketing (1) ft 2 1.57 0.04 1.57 0.04 (1) These debris materials were included in the sacrificial strainer area.

Attachment 3 to AEP:NRC:8054-02 Page 188 Table 3f4-3 Quantity of Debris at Remote Strainer for DEGB and DGBS Test Test Debris Type Units DEGB Tit DGBS Quat Quantity-Quantity RMI ft 2 0 0 0 0 Cal-Sil Fines Ibs 164.108 4.003 41.412 1.010 Marinite I Fines lbs 0.0906 0.002 0 0 Marinite 36 Fines lbs 0.72 0.018 0.532 0.013 Min-K Ibs 0.832 0.020 0 0 Epoxy Paint (inside ZOI) Ibs 111.436 2.718 2.08 0.051 Alkyd Paint (inside ZOI) lbs 0.312 0.008 0.312 0.008 Unqualified OEM Epoxy (outside ZOI) lbs .12.672 0.309 12.672 0.309 Unqualified OEM Alkyd (outside ZOI) lbs 67.86 1.655 67.86 1.655 Unqualified Non-OEM Epoxy (outside ZOI) lbs 0 0 0 0 Unqualified Non-OEM Alkyd (outside ZOI) lbs 2.124 0.052 2.124 0.052 Unqualified Cold Galvanizing Compound lbs 272.125 6.637 272.125 6.637 Dirt/Dust lbs 73.1 1.783 73.1 1.783 Latent Fiber ft 5.375 0.131 5.375 0.131 Fire Proof Tape Fines ft3 0.0312 0.001 0.0312 0.001 Ice Storage Bag Fibers ft 0.01118 0.0003 0.01118 0.0003 Ice Storage Bag Liner Shards ft 0.0001 0.0000 0.0001 0.0000 Pieces of Work Platform Rubber ft3 0.00086 0.0000 0.00086 0.0000 Fire Proof Tape Pieces (1) ft 0.4032 0.010 0.4032 0.010 Electromark Label (inside ZOI) (1) ft2 0.4128 0.010 0.4128 0.010 Electromark Label (outside ZOI) (1) ft2 18.559 0.453 18.559 0.453 Unqualified Labels (1) ft2 8.5602 0.209 8.5602 0.209 Flex Conduit PVC Jacketing (1) ft2 0.471 0.011 0.471 0.011 (1) These debris materials were included in the sacrificial strainer area.The debris quantities listed in the tables above were. converted to metric units for the testing.The RMI and fiber debris were converted to an equivalent mass for determination of the quantity to be used for testing. Tables 3f4-4 through 3f4-6, below identify the materials used for testing.The "stone flour" entry at the bottom of Tables 3f4-4 through 3f4-6 refers to items from Tables 3f4-1 through 3f4-3 that are not specifically listed on Tables 3f4-4 through 3f4-6, and were not considered to be materials that contributed to blocked strainer area. These items were represented by stone flour in the testing. A discussion on the acceptability of using stone flour as a surrogate for coating debris is provided in the response to Information Items 3.h.3 and 3.h.4. The use of stone flour as a surrogate for materials in Tables 3f4-4 through 3f4-6 is considered acceptable on the same basis as was provided for the coating debris.~~2 Attachment 3 to AEP:NRC:8054-02 Page 189 Table 3f4-4 Debris Quantities at Main Strainer During Pool Fill Test Material Units Mass"Pool Fill" Fibrous Debris Nukon kg 0.152 Particulate Debris RMI kg 4.796 CalSil kg 1.387 Marinite I kg 0.000 Wollastonite kg 0.001 Min-K kg 0.006 Unqual Non-OEM Epoxy kg 0:000 Unqual Non-OEM Alkyd kg 0.000 Stone Flour for Cold Galvanizing kg 0.000 Stone Flour kg 1.989 Table 3f4-5 Debris Quantities at Main and Remote Strainer During Recirculation for DEGB Mass Mass Test Material Unit Main Strainer Remote Strainer Fibrous Debris Nukon kg 0.210 0.155 Particulate Debris RMI kg 8.248 0.000 CalSil kg 1.984 1.822 Marinite I kg 0.001 0.001 Wollastonite kg 0.003 0.002 Min-K kg 0.008 0.009 Unqual Non-OEM Epoxy kg 0.092 0.000 Unqual Non-OEM Alkyd kg 0.023 0.024 Stone Flour for Cold Galvanizing kg 5.360 2.018 Stone Flour kg 2.971 4.074 Table 3f4-6 Debris Quantities at Main and Remote Strainer DGBS During Recirculation for Mass Test Material Unit Mass Remote Main Strainer Strainer Fibrous Debris Nukon kg 0.210 0.155 Particulate Debris RMI kg 4.439 0.000 CalSil kg 0.792 0.463 Marinite I kg 0.000 0.000 Attachment 3 to AEP:NRC:8054-02 Page 190 Mass Test Material Unit Main Remote Main Strainer Strainer Wollastonite kg 0.002 0.002 Min-K kg 0.000 0.000 Unqual Non-OEM Epoxy kg 0.092 0.000 Unqual Non-OEM Alkyd kg 0.023 0.024 Stone Flour for Cold Galvanizing kg 5.360 2.018 Stone Flour kg 1.469 2.258 The Wollastonite, listed in Tables 3f4-4 through 3f4-6, was the surrogate material used for the fibers in Marinite 36, which is the asbestos containing fire board material installed in the CNP containments.

I&M performed an evaluation of the Marinite 36 (Reference

91) to determine an appropriate surrogate for testing. Since Marinite 36 is a combination of asbestos fibers (30% by weight) and calcium silicate material, the quantity of Cal-Sil used for testing was increased by the quantity of calcium silicate material contributed by Marinite 36, in addition to that contributed by the Wollastonite fibers. As can be seen from the tables, the contribution of Wollastonite was a very small fraction of the overall quantity.Debris Preparation RMI used in the testing was composed of pre-shredded stainless steel foils with a thickness of 0.002 in. The foils were prepared by a commercial shredding company, which tears and crumples the RMI foils using a mechanical process to approximate the size distribution given in Appendix VI, Page VI-16, of the SER. Figure 3f4-9, below, provides a photograph of the representative RMI debris used for testing. The unit of measure on the ruler in the photograph is centimeters.

Attachment 3 to AEP:NRC:8054-02 Page 191 esentative RMI Debris Used for T The fiber material used in the testing was low density Nukon fiberglass.

The preparation of the fiber material was as described below." The fibers were then baked by placing them in an oven with a regulated temperature of 250 0 C for 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months prior to testing." The fibers were then cut in pieces approximately 50 mm x 50 mm in size.* The material was then weighed.* The fibers were then split into batches of 3 dm 3 to 4 dm 3 (0.1 to 0.14 ft 3).* Each batch was then soaked in 2 liters (- 1/2 gal) of water.* Adherence between fibers was then decomposed by a high pressure water jet with a pressure capacity of 100 bar, with the jet at a distance of +/- 0.05 m from the water surface, for approximately 4 minutes for each batch.* The insulation was then visually inspected to ensure that the decomposed fiber was suspended in water in pieces smaller than 10 mm.* Several batches, prepared as described above, were then mixed together to create the quantity needed for testing.

Attachment 3 to AEP:NRC:8054-02 Page 192 Figure 3f4-1 0, below, provides a photograph of the fiber debris that was prepared for the testing.The fiber debris solution is approximately 18 in diameter.re 3f4-10 Fiber Debris Prepared for Testina The Cal-Sil, Marinite I, and Min-K materials used in the testing were pulverized into a fine powder by mechanical means. Since the Min-K installed at CNP has a fiberglass covering, the covering was shredded into fines for the testing. The Wollastonite material did not require any preparation since it was in its uncombined form. Refer to Figures 3f4-11 through 3f4-14 for pictures of the prepared Cal-Sil, Marinite I, Min-K, and Wollastonite debris.

Attachment 3 to AEP:NRC:8054-02 Page 193 Attachment 3 to AEP:NRC:8054-02 Page 194 Attachment 3 to AEP:NRC:8054-02 Page 195 The unqualified non-OEM epoxy and alkyd coatings test debris was prepared by first coating plastic sheets with the material.

Once dry, the material was peeled from the plastic. The material was then processed through a brush/leaf shredder at least twice. To create very small particles, a portion of the material was then processed in a food processor.

The coatings materials were sieved to achieve the correct size distribution.

The coating debris was represented in the testing by chips as follows:* 10% by weight -250 to 500 microns diameter* 80% by weight -500 to 1000 microns diameter 0 10% by weight -1000 to 4000 microns diameter The response to Information Item 3.h.3 provides additional information regarding these coatings debris sources. Figures 3f4-15 through 3f4-20, below, provide photographs of the prepared non-OEM epoxy and alkyd coatings.

I Attachment 3 to AEP:NRC:8054-02 Page 196 Attachment 3 to AEP:NRC:8054-02 Page 197 3f4-19 500 -1000 Micron Head Loss Testinq Debris-only strainer head loss testing was performed on the large scale test loop for both DEGB and DGBS scenarios.

The tests that were performed were 1) the "standard" head loss test consisting of stepped flow rates and stepped homogeneous debris additions, 2) debris sequence tests, and 3) event sequence tests. The details associated with each test are provided below.

Attachment 3 to AEP:NRC:8054-02 Page 198 DEGB Head Loss Test The DEGB head loss test steps, with the data recorded at the designated points are provided in Figure 3f4-21, below.Figure 3f4-21 DEGB 100% Flow 100% Debris Extended Duration Head Loss Test with Flow Reduction and Flow Restart to 120% Flow 120% Debris Test Time [hh:mm) Fluid tampern- Ap U4ube Ap Flow rato Remarks step ture (MmHt (mbarj [ml]0 09:18 16.66 0.1 0.0615 48 60% flow rate 1 12:29 17.14 5.6 5.716 48 60% flow rate, 60% debris 2 14:15 17.44, 14.3 14.33 64 80% flow rate, 80% debris 09)04107 3* 16:37 21.96 23.6 22.98 80 100% flow rate, 100% debrts 4 18:19 21.94 14.6 14.44 61.1 76.4% flow rate, 100% debris 5 19:31 21.84 7.9 7.95 42.2 52.8% flow rate, 100% debris 6 20:01 21.78 2.2 2.11 21.1 26.4% flow rate, 100% debris Pump stop; restart 7 20,18 21.76 0.3 0.14 21.1 26.4% flow rate, 100% debris 8 21:05 21.66 0.6 0.60 40 50% flow rate, 100% debris.09105&07 9* 00:09 22.08 13.5 13.494 80" 100 % flow rate, 100% debris 10 02:10 22.36 39.7 38.856 96 120% flow rate, 120% debris The annotation of Test Steps 3 and 9 with an

indicates that were taken during these steps as indicated in Figure 3f4-22.flow propeller measurements As discussed in the response to Information.

Item 3.f.1, debris additions occurred to the respective side of the test strainer at the designated points in the test. The debris was added directly in front of the strainer pockets to minimize any settling of the debris. No credit was taken for any near-field settling of material in this or any of the tests performed.

The data that was recorded at each of the test steps was obtained at the condition described in the "Remarks" column. The test steps are described below.Test Step 0: Test Step1: Test Step 2: Test Step 3: Flow was established at 60%.60% of the debris was added to the main and remote strainer sides, then head loss was allowed to stabilize.

20% of the debris quantities were added to the respective side of the test strainer, i.e., the total debris was now 80%. Head loss was allowed to become reasonably stable. kAt that time, flow was increased to the 80%point. Head loss was monitored until it was again reasonably stable.Another 20% debris addition was made, and head loss was monitored until it became reasonably stable. Flow was then increased to 100%. The objective of this part of test, and the subsequent DGBS test, was to Attachment 3 to AEP:NRC:8054-02 Page 199 determine if head loss would continue to increase over an extended time.The tests were to maintain flow for a minimum of 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months following achieving a 100% flow, 100% debris condition.

After the 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months time, head loss was checked to determine if it was stable, i.e., less than 1%increase in two consecutive 30 minute periods. Once stable head loss was achieved, flow propeller measurements were taken to provide an approximate flow distribution between the main and remote strainers.

This information was used as one of the inputs to establish an overall system head loss since the waterway connecting the remote strainer to the recirculation sump could not be tested in the test loop. After the propeller measurements were obtained, the testing proceeded into a flow reduction sequence.

Since I&M is utilizing the GR and SER Chapter 6 approach for the DEGB, test data to determine the CNP-specific debris mixture response to a flow reduction sequence was an important input to the effectiveness of reducing flow and its result on head loss across the strainer.Test Step 4: Test Step 5: Test Step 6: Test Step 7: Test Step 8: Test Step 9: Test Step 10: The flow reduction sequence consisted of first reducing flow equivalent to removing one CTS pump from operation.

Head loss was allowed to become reasonably stable between each of the flow reduction steps.The second flow reduction step was to reduce flow equivalent to removing another CTS pump.The third flow reduction step was to reduce flow equivalent to removing an RHR pump.The final flow reduction step was to reduce flow to zero (equivalent to stopping the last running pump), and then restarting flow equivalent to an RHR pump within about a minute to a minute and a half. The purpose of this step was to determine if a limited hydraulic backflush would occur.Note that I&M is not crediting stopping all pumps to mitigate a high head loss condition at the recirculation sump within design basis response to an event. This action would be solely a "beyond design basis" action.Once flow was re-established equivalent to restarting an RHR pump, it was incrementally increased equivalent to restarting a CTS pump, The flow was increased equivalent to starting a second RHR and CTS pumps at the same time. Head loss was allowed to become reasonably stable between the incremental changes in flow.After a stable head loss at 100% flow was achieved, the debris quantity was increased to 120% of the calculated debris quantity, followed by an increase in flow to the 120% value.

Attachment 3 to AEP:NRC:8054-02 Page 200 The step results of this sequence are provided in Figure 3f4-21 above for the DEGB. Based on the testing, it was determined that a flow reduction sequence would be effective in reducing the head loss across the recirculation sump strainers.

Based on the reduction in head loss observed during the testing, it is not anticipated that removal of more than one pump would be required to return head loss to an acceptable value.Figure 3f4-22, below, provides the flow propeller measurements taken at Test Steps 3 and 9. At each of the required test points, two data points were taken at each of the flow holes.Refer to Figure 3f4-2 for the location of the measuring points.Figure 3f4-22 Flow Propeller Measurements for the DEGB Test) low Window 1 Window 2 Window 3 Window 4 Window 5 Window 6 Tfws3ment 4[1 I43m 1 o 38 271m 270 2q37 TS 3:_1 401 433 389 271 270 237 TS 3.2 426 462 401 270 238 245 TS9.1 805 539 585 120 47 52 TS 2 .553 545 614 114 44 63 Figure 3f4-23, below, provides the graphical representation above for the DEGB scenario.of the sequence described Figure 3f4-23 DEGB Test Plot 20MO 1800 1400 11200 1000 aw so 45 40 35.30 .251.20 As 10.5 ,0 600 400 200 0 .o 9:04:10 1I5:. 2 1:54:25 1454:12 20:44:14 2:34:17 8:24:19 14:14i21 20.04:23 As can be seen from the test plot, the head loss during the extended time at 100% debris, 100% flow varied within about a 5 mbar range, but ultimately reached a very stable value.To provide for equivalent comparison of the head loss values obtained, the head loss values Attachment 3 to AEP:NRC:8054-02 Page 201 were normalized to 200C. This temperature is below the temperature that would be expected in the containment recirculation sump pool, which provides conservative results.The highest head loss during that period was 11.3 in H 2 0 at approximately 16 hours1.851852e-4 days 0.00444 hours 2.645503e-5 weeks 6.088e-6 months after achieving the 100% debris, 100% flow condition.

The head loss at the end of the 24-hour period was approximately 9.5 in H 2 0 and slowly decreasing.

DGBS Head Loss Test The same test sequence was performed for the DGBS test as was described for the DEGB test. In the figures provided below, Figure 3f4-24 provides the DGBS test data points, Figure 3f4-25 provides the flow propeller measurement data, and Figure 3f4-26 provides the test plot.Figure 3f4-24 DGBS 100% Flow 100% Debris Extended Duration Head Loss Test with Flow Reduction and Flow Restart to 120% Flow 120% Debris Test Time [hh:mm] Fluid tempera- Ap U-tube AP Flow rate Remarks step tufr (C] [cmiNA (mbarj ("m111 1 14:44 17.18 1.7 1.764 48 60% flow rate, 60% debris 2 16:05 17.34 5.8- 5:782 64 80%O flow rate, 80% debris 3* 17:26 21.86 13.0 12.825 80 100% flow rate, 100% debris 08128/07 4 18:01 21.88 8.2 7.990 61.1 76.4%f fow rate, 100% debris 5 18:38 21.84 4.3 4.164 42.2 52.8% flow rate, 100% debris 6 19:05 21.80 1.2 1.134 21.1 26.4% flow rate, 100% debris k _Pump stop; restart 7 19:25 21.74 0.2 0.12 21.1 26.4% flow rate, 100% debris 8 19:56 21.70 0.3 0.293 40 50% flow rate, 100% debris 08129107 9* 01:09 -22.32 9.6 9.840 80 10o % flow rate, 100% debris 10 08:02 23.86 24.5 23.450 96 120% flow rate, 120% debEs Figure 3f4-25 Flow Propeller Measurements for the DGBS Test{) Flow Window I Window 2 Window 3 Window 4 Window 5 Window 6 measurement

[rpm] [rpm] [rpm] [rpm]. [m] [r m]TS 3:1 363 341 313 356 365 293 TS 3:2 364 336 345 345 371 313 TS9: 1 410 414 379 268 275 235.... TS9:2 413 443 424 282 261 236 Attachment 3 to AEP:NRC:8054-02 Page 202 Figure 3f4-26 DGBS Test Plot 1200 1000 Z W0 A 400 L.-30 25 20~0 200 0 1-3 -13:*D:00 19.49.02 2:29:05 9:09:07 iS 4d:10 2229:12 s:0o:1s As can be seen from the test plot, the head loss during the extended time at 100% debris, 100% flow varied within an approximate 2 mbar range, and reached a stable value. The highest head loss during the 100% period was 5.6 in H 2 0 at approximately 23 hours2.662037e-4 days 0.00639 hours 3.80291e-5 weeks 8.7515e-6 months after achieving the 100% debris, 100% flow condition.

The head loss at the end of the 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months period was approximately 5.4 in H 2 0 and slowly decreasing.

The head loss values provided are the 20 0 C normalized values.DEGB Event Sequence Test The steps of the test that were performed, with the data recorded from the test at the designated points are provided in Figure 3f4-27, below.Figure 3f4-27 DEGB Event Sequence Test Tea Time 0 0luM temeira- Ap U-lbd AP Flow raft ReMtlmM steU". rcq I-HA~ ORM4. W"'0 8.13 15.44 0.0 0038 30.6 38.2% flow rate 1 851 15.46 0.2 0.213 30.6 38.2% flow rate, 30 nmn stabiulzaton with pool Al debris to main sWrainer 2 911 15.50 0.4 0.567 39.4 49.3% flow rate, 15 min stabilzation with pool fir detis ato main strainer 3 923 15.54 3.0 3.081 40 50% flow rete, T stabitization removed blanking cover, 100% debris 9:44 Adding of 384 kg Main and 1.52k Remote stone flour due to new_oGalsc"Zincdensty 250 bM*)4* 14.29 17.16 21.8 21.380 80 100% flow rate wtth 100% debris 5 16.08 17.54 26.2 25.581 80 100% flow roe, 100% debris+ 25% increase of unqualified parnt chi:s to main and remote strainer Attachment 3 to AEP:NRC:8054-02 Page 203 The annotation of Test Step 4 with an

indicates that flow propeller measurements were taken during this step as indicated in Figure 3f4-28.Test Step 0 Test Step 1 Test Step 2: Test Step 3 An equivalent flow was established through the main strainer side of the test strainer (38.2%), with the remote strainer side blocked off, that was calculated in Reference 28 to exist during the pool fill period of an event.The quantities of debris that are assumed to be at the main strainer, as given in Table 3f4-4, were added to the main strainer side. This configuration was then maintained for 30 minutes to establish the debris bed.The flow rate was increased to 49.3% and allowed to stabilize approximately 15 minutes.After 30 minutes, the following steps were performed simultaneously.

The flow rate was increased to 50% to represent the transfer of one RHR and one CTS pump to the recirculation alignment.

The blanking cover was removed from the remote strainer side of the test strainer.Debris additions were made to both sides of the test strainer to bring the total debris quantity to 50%.These conditions were maintained for approximately 5 minutes.Flow was increased to 100% and debris for both the main strainer and remote strainer sides were increased to 100% of the total recirculation flow quantities as given in Table 3f4-5. Head loss was then allowed to reach stable conditions of less than 1% increase in two consecutive 30 minute periods. After stable head loss conditions were reached,, flow propeller measurements were obtained.An additional 25% of the total unqualified coatings, as chips, were added to the respective sides of the test strainer.

The test was then allowed to run for approximately one and a half hours, at which time a reasonably stable head loss had been achieved.Test Step 4 Test Step 5 The objective of this test, and the similar DGBS test, was to determine if the expected pre-loading of the main strainer during pool fill would result in head loss values significantly different than those determined during the stepped sequence debris and flow increases described previously in the response to this information item. The objective of adding the extra paint chips was to determine the impact on the strainer head loss of this magnitude increase in paint chips.

Attachment 3 to AEP: NRC:8054-02 Page 204 Figure 3f4-28, below, provides the flow propeller measurements taken at Test Step 4. Two data points were taken at each of the flow holes. Refer to Figure 3f4-2 for the location of the measuring points.Figure 3f4-28 Flow Propeller Measurements for the DEGB Event Sequence Test 0) F"Mw Window I WIndow 2 WindowI 3 Wow 4 d5 Window 8 rnoaswsmre"t Yinxn Irml M-)I1 [mm? YM s i fm TS 4:1 384 378 400 151 158 138 TS 4. 2 428 458 478 113 149 134 Figure 3f4-29, below, provides a graphical representation of the sequence described above for the DEGB event sequence scenario.Figure 3f4-29 DEGB Event Sequence Test Plot 2600 240D 120 30 25 20 I 10 5 400 o -2 8:0521 t05:22 100522 11D05.22 12:0523 13:05 23 14:0624 15:05,24 16805.24 As can be seen from the test plot, the head loss slowly increased to a peak value over an approximate three hour period and then varied within an approximate 2 mbar range until head loss started to steadily decrease until the additional significant quantity of paint chips were added to the test loop. The highest head loss during the 100% period was 8.4 in H 2 0 at approximately four hours after initiation of the recirculation phase. The head loss at the end of the 100% test period was approximately 7.9 in H 2 0 and slowly decreasing.

The head loss values provided are the 200C normalized values.

Attachment 3 to AEP:NRC:8054-02 Page 205 DGBS Event Sequence Test The same test sequence was performed for the DGBS event sequence test as was described for the DEGB test, except that the additional coatings chips were not added at the end of the test. Figure 3f4-30 below provides the DGBS event sequence test data points, Figure 3f4-31 provides the flow propeller measurement data, and Figure 3f4-32 provides the test plot.Figure 3f4-30 DGBS Event Sequence Test Tomt k thhpmM) Fid" imtpers- Ap U-tul wt ReAwatrw Step th"[ r[c [cmnHA Cmbafl DRIN 0 8:08 13.36 0.10 0.042 30.6 38.2% flow rate 1 8:50 13.48 0.15 0.115 30.6 382% flow rate, 30 min stabOuabon with "pool f dens to main strw 2 9:06 13.52 0.25 0.192 39.4 49.3% low raft, 15 min stabuIizaton with oo W debrIS to main strainer 3 9:17 13.58 0.8 0.903 40 50% flow rate, r stabustion with 100% debis to Main and Remote stne and removed biang cover 4V 13:35 15.14 20.4 19.95 80 100% fow rate, 100% debls Figure 3f4-31 Flow Propeller Measurements for the DGBS Event Sequence Test O Flow Window I Window 2 Window 3 Window 4 Window 5 Window6 rmsnuc, mfnt [rn [pm] [nxl MI [(PM Ion!n TS4:1 572 566 559 148 156 118 TS 4.2 58 529 563 144 158 109 Figure 3f4-32 DGBS Event Sequence Test Plot 1500 1250 750 1500.25.20 i.15*ioA 03 250 0 79 75.M35 a:39,35 0335 91.36 92:9%36 10.39:36 11.19.36 11:59.37 12.3937 13:19:37 Attachment 3 to AEP:NRC:8054-02 Page 206 As can be seen from the test plot, the head loss slowly increased to a peak value and then varied within an approximate 1 mbar range until head loss started to slowly decrease.

The highest head loss achieved during this test was 7.2 in H 2 0 approximately 3 3/4 hours after reaching 100% flow. At the end of the test, the head loss was at approximately 7.0 in H 2 0 and decreasing slowly. The head loss values provided are the 200C normalized values.DEGB and DGBS Debris Sequence Tests The test was initiated by establishing 100% flow in the test loop. Nukon fibers, prepared as described above in "Debris Preparation," were added in increments of 40%, 40%, and 20%of the total quantity determined, as given in Table 3f4-5, with five pool turnovers (15 minutes, 35 seconds) provided between each addition.

The Cal-Sil and Marinite debris were then added in the same incremental steps with the same pool turnovers provided between each addition.

The particulate debris was then added, again with the same incremental steps and time between steps. Finally, the RMI was added in increments of 50% per addition, with the same pool turnovers provided between additions.

The objective of this test, and the similar DGBS test was to determine if a debris addition sequence that pre-loads the test strainer with purely fibrous debris, then with debris that contains both fibers and particulate, in the quantities that have been calculated for CNP, would potentially form a thin bed that would result in higher head losses than a homogeneously mixed debris when the substantial quantities of particulate were added.Strainer Head Loss Testinq Conclusions Based on the strainer testing performed, the addition of a homogenous debris mixture has been determined to be the most limiting for CNP. The response to Information Item 3.f.10 provides the most limiting strainer head loss values as a result of this testing, normalized to 200C. This temperature was chosen solely as a convenient point to establish equivalent head loss values since, as could be seen from the test plots, temperature in the test loop tended to increase during the test sequences.

Note that, during testing, the strainers performed as a very effective filter for removing suspended particulate from the flow stream. For the long duration tests, the pool water clarity was very high. This is also evidenced by the significant reduction in measured turbidity in the test loop. Water samples were collected at selected points during the tests performed.

I&M will report on the analysis of those samples in the final response to GL 2004-02 in accordance with the schedule provided in the response to Information Item 2.All information on chemical effects testing is provided in the response to Information Item 3.0.I&M Response to Information Item 3.f.5 Due to the unique configuration of the CNP recirculation sump strainers, there are no conditions where the maximum predicted debris loads would cause a loss of available strainer area. The main strainer consists of vertical rows of pockets, approximately 5 ft high by 15 1/2 ft across.Refer to the Figures 3j1-1 and 3j1-2 in the response to Information Item 3.j.1 for a sketch of the Attachment 3 to AEP:NRC:8054-02 Page 207 main strainer and a photograph of the installed configuration.

The main strainer is located inside the loop compartment and would be loaded with a substantial quantity of debris during the pool fill (injection) phase of the event. Upon transfer to recirculation flow, since the majority of the debris is inside the loop compartment, the main strainer would become the most heavily loaded of the two strainers.

The remote strainer, located in the annulus, would be exposed to less debris than the main strainer.

As described in the response to Information Item 3.e.6, the total debris fractions for many of the debris types would exceed 1.0 if the fraction assumed to reach the main strainer and the fraction assumed to reach to the remote strainer were summed.Since neither strainer is within a pit or other confined area, the concern of filling an interstitial volume does not exist.. Based on the design configuration, the recirculation sump strainers would be capable of accommodating the maximum quantity of debris predicted to arrive.I&M Response to Information Item 3.f.6 The only significant fiber debris source at CNP is that material assumed to result from latent debris. The quantity of fiber assumed (30 Ibs, 12.5 ft 3) would form a uniform 1/8 in thin bed on 1200 ft 2 of the strainer surface area. Since there will be 1972 ft 2 of strainer area in each unit following completion of the plant modifications described in the response to Information Item 3.j, a fiber-only thin bed is not credible for CNP. The most problematic debris constituent at CNP, with respect to thin bed formation, is Cal-Sil. Since there is not a defined thickness for a Cal-Sil thin bed, it is assumed that a Cal-Sil thin bed will form on the CNP strainers.

During vendor strainer testing, debris sequence tests were performed for both DGBS and DEGB debris loads (References 80 and 81). As described in the response to Information Item 3.f.4, the debris sequence test was performed in the following sequence.

The flow rate was established at 100% equivalent flow. Nukon fibers, prepared as described above in "Debris Preparation," were added in increments of 40%, 40%, and 20%, with five pool turnovers (15 minutes, 35 seconds) provided between each addition.

The Cal-Sil and Marinite debris were then added in the same incremental steps, with the same pool turnovers provided between each addition.

The particulate debris was then added, again with the same incremental steps and time between steps. Finally, the RMI was added in increments of 50% per addition with the necessary pool turnovers provided between additions.

the measured head loss, after allowing for stabilization, was 3.993 mbar (1.6 in H 2 0) for the DGBS test, and 11.9 mbar (4.8 in H 2 0) for the DEGB test. These head loss values were not normalized to 200C. Figures 3f6-1 and 3f6-2 provide the plots of these tests. These head loss results were significantly below the head loss results described in the response to Information Item 3.f.4 which combined the debris types for introduction into the test loop. For the tests described in Information Item 3.f.4, the debris quantities were the maximum quantities assumed from the debris generation and debris transport analyses, scaled to the test setup, as provided in Table 3f4-5. Discussion of the scaling used for strainer vendor testing is included in the response to Information Item 3.f.4.

Attachment 3 to AEP:NRC:8054-02 Figure 3f6-1 DGBS Debris Sequence Plot Test 2121_4: DGBS Debris Sequence Case I Page 208 1400 1200 z 1000 E 800.2 60 CL E 400 1!4 3 2 I 200 0 -PC 8:04:01 0 8:54:02 9:44:02 10:34:02 11:24:03 12:14:03 13:04:03 13:54:04 Figure 3f6-2 DEGB Debris Sequence Plot Test 2121_5: DEGB Debris Sequence Case I 2500o 2000-S1500-!0oo.500.16 14 12 10 61 4 0 .8.07;39&.57;39 9-47.40 10.37,40 11:27.40 12:17-41 13107,41 Attachment 3 to AEP:NRC:8054-02 Page 209 This testing demonstrates that the CNP strainers would be capable of resisting the formation of a fully developed fiber thin bed, but may be susceptible to formation of a partial thin bed from the Cal-Sil debris. Refer to the test results described in the response to Information Item 3.f.4.I&M Response to Information Item 3.f.7 The strainer design maximum head loss at minimum recirculation water level for a DEGB is 2.8 ft H 2 0. The strainer design maximum head loss at minimum recirculation water level for a DGBS is 2.65 ft H 2 0. This design limit is based on the available driving head of water at the fully vented recirculation sump. This is in accordance with information contained in NUREG/CR-6808 (Reference 89), Section 1.3.2. One-half the available pool height (minus 0.3 ft for the curb height) was used to establish the available driving head for flow through the strainer, which establishes the maximum allowable head loss across the strainer.

This head loss limit protects the calculated vortex limit of 601.5 ft described in the response to Information Item 3.f.3. As discussed in the response to Information Item 3.g.16, the elevation associated with the required NPSH for the pumps taking suction from the recirculation sump is substantially below the elevation associated with the assumed maximum head loss. The maximum head loss assumed for the structural analysis is approximately 15 ft, significantly greater than the maximum allowed head loss for recirculation operation.

I&M Response to Information Item 3.f.8 There are several conservatisms that provide margin for the assumed strainer head loss and the maximum allowable strainer head loss. These conservatisms, and quantifiable margins (where available) are described below. These conservatisms are not necessarily captured directly in the vortex and head loss analyses, but are reflected in the inputs to those analyses.Containment Water Level The containment minimum water level analysis documented in Reference 32 applied the following conservatisms to minimize ice melt which is a significant contributor to overall sump level." The mass and energy release from the RCS summed the contribution of water and steam flows leaving the RCS and assumed a thermodynamic equilibrium for this mixture. This maximized the water enthalpy and minimized the steam released to the containment atmosphere.

The actuation setpoint for CTS was biased low such that CTS would provide a greater contribution to cooling the containment atmosphere." The CEQ fan flow was biased low to minimize flow through the ice condenser.

CTS was assumed to remain in service until a low biased reset point was reached." The volumes of the annulus and loop compartment were modeled without displacement from internal structures.

Including a conservatively low volume for this displacement would provide an additional 2.2 in to the minimum water level.* Assuming a maximum cooldown rate of 100°F/hr decreased the energy discharged into containment, decreasing the ice melt rate.

Attachment 3 to AEP:NRC:8054-02 Page 210* Conservatively high flow rates were assumed for the ECCS and CTS while on recirculation.

A reasonably assumed 10% reduction in flow would result in an approximate 15% reduction in head loss.Based on these considerations, and assuming the conservatively determined vortex limit of 601.5 ft, the allowable head loss across the strainer could be increased by a significant margin.Debris Quantity The quantity of debris assumed to arrive at the sump strainers has been conservatively established such that in many cases, the deliverable quantity is greater than the total quantity of debris generated.

Vortex Limit The vortex limit conservatively considers the potential for vortex formation as a function of the column height of water from the water level in the vent pipe to the recirculation sump suction piping. For CNP's design, there is no flow in the vent pipe, thus the potential for a vortex to develop in the vent pipe and continue to the suction piping is not considered to be a probable event until such time the water level in the sump had dropped significantly below the assumed elevation.

For any vortices that form in the front section of the sump, the probability of a vortex extending below the partition wall in the sump is remote. Refer to Figure A4-1, in Attachment 4.I&M Response to Information Item 3.f.9 As described in the response to Information Item 3.f.4, the strainer installation at CNP consists of a main strainer at the recirculation sump in the loop compartment, and a remote strainer in the annulus with a connecting waterway to the recirculation sump. Since strainer head loss testing was performed with parallel path equivalent main and remote strainers, the contribution of the waterway to the overall system head loss was not tested. An analysis by I&M (Reference 142) was performed to determine the head loss for the installed configuration based on the strainer testing performed at CCI. Additionally, CCI performed an analysis to determine head loss (Reference 143) of the installed configuration based on the strainer testing results.As shown in Figures 3f4-1 and 3f4-2, the configuration used during strainer testing resulted in different areas for each side of the strainer test assembly to represent the main and remote strainers.

The flow to each pool area on each side of the strainer assembly was passed through equivalent sized flow holes to allow for comparative flow measurements to evaluate the flow split between the strainers.

The results of these flow splits during clean strainer head loss testing were used as inputs to the clean strainer head loss determination.

For the clean strainer head loss determination, Reference 142 used results obtained from Reference 27 and Reference 81 to determine the overall system head loss. With the information from the strainer testing and the CFD-based hydraulic analysis, the determination of applicable K-factors for the main and remote strainer were calculated.

Once these K-factors were obtained, the head loss for the main strainer, remote strainer, and waterway were calculated.

For the installed configuration, the head loss of the main strainer will be equal to the Attachment 3 to AEP:NRC:8054-02 Page 211 sum of the head loss of the remote strainer and the head loss of the remote waterway.

The calculation determined the system clean strainer head loss to be 0.018 ft H 2 0.CCI performed a system head loss determination subsequent to the completion of the calculation described in the previous paragraph.

CCI used the clean strainer head loss obtained from the testing performed on the MFTL, with a velocity head correction applied due to the location of the downstream pressure tap. With the correction, the as tested clean strainer head loss was 0.072 ft H 2 0. This clean strainer head loss was then used to determine a K-factor for the strainer.

To determine the system clean strainer head loss, CCI performed a CFD analysis to predict the head loss in the waterway.

This CFD analysis evaluated the 100% and 50% flow cases. Figure 3f9-1 depicts the calculation domain used in the analysis.

This domain included a portion of the remote strainer, the waterway, and an arbitrary large box to represent the sump. The use of the large box to represent the sump to ensure the velocity head at the waterway exit does not influence the losses calculated for the waterway.Figure 3f9-1 CCI CFD Calculation Domain Strainer connectin duct r~utletThe computational mesh was created by the ANSYS ICEMCFD tool. The mesh was fully hexahedral and contained 786,000 cells. Figure 3f9-2 illustrates the computational mesh used for the analysis.For the analysis, the CFD code AnsysCFX, Version 11, was used. It used a finite volume scheme to discretise the differential equations governing the conservation of mass, momentum, and energy (Navier-Stokes equations).

The differential equations were first integrated over individual computational cells and then approximated in terms of cell-centered nodal values of the dependent variables.

This approach had the merit of ensuring that the discretised forms preserved the conservation properties of the parent differential equations.

The "High Attachment 3 to AEP:NRC:8054-02 Page 212 Resolution" differencing scheme was used for the spatial discretisation.

Implicit methods were employed to solve the steady-state equation by an iterative technique, i.e. the time derivate terms were deleted from the finite volume equations.

For the transient runs every time step was solved with 4 -8 inner iterations that were exported as a resulting file. The turbulence was modeled by the Shear Stress Transport model. The temperature assumed in the analysis was 100 0 F.Figure 3f9-2 Computational Mesh The CFD analysis determined the head loss of the waterway at the equivalent 100% flow rate to be 1.105 ft H 2 0, and the head loss at the equivalent 50% flow rate to be 0.278 ft H 2 0. These head losses were then used to determine the appropriate K-factor.

With the determined K-factor, the system head losses were then calculated using a series of calculations that considered the distribution of flow between the main and remote strainers.

The resulting system clean strainer head loss was determined to be approximately 0.05 ft H 2 0.As determined by I&M's calculation, and CCI's analysis, the clean strainer head losses for the CNP configuration are very low, providing an insignificant contribution to debris laden strainer head loss.I&M Resnonse to Information Item 3.f.10 I M Resnonse to Information Item V.10 As described in the response to Information Item 3.f.9, a similar methodology was used for determining the system head losses for debris laden strainers as it was for clean strainers.

Attachment 3 to AEP:NRC:8054-02 Page 213 The limiting debris head loss case for the DEGB was determined to be an all debris case, designated as Test Case T2121-3, that utilized homogeneous debris mixtures added to the test loop in increments of 60% for the first debris addition, and then 20% debris addition for the next two additions (100% total debris). For the test, the flow rate was established at 60% flow and then the 60% debris quantity was added. As described in the response to Information Item 3.f.4, the test pool was separated so that debris additions would be made to the main and remote strainer sides of the test configuration per the test specification directed quantities.

These test specification quantities were provided to CCI by I&M for the testing. For subsequent increases in flow or debris quantities, the debris quantity was increased to the next increment, e.g., 60% to 80%, then the head loss was allowed to stabilize prior to increasing the flow rate to the next increment, e.g., 60% to 80%. Again, the head loss was allowed to reach a level of stability prior to increasing the debris quantity again. After achieving 100% debris and 100%flow, the test was allowed to run for 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months . The highest head loss achieved during the 24-hour run was 11.3 in H 2 0 at approximately 16 hours1.851852e-4 days 0.00444 hours 2.645503e-5 weeks 6.088e-6 months after 100% debris, 100% flow was achieved.

The head loss at the end of 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months from the 100% debris, 100% flow point was approximately 9.5 in H 2 0 and slowly decreasing.

The head loss values provided are the 20°C normalized values. Figure 3f1 0-1, below, provides the plot for this test.Figure 3f10-1 DEGB All Debris Head Loss Test Plot 2000-1800 1600 1400,.50 45*40#1200 1000 600 400 200 35 30 I 25 20~15 0 0 o 9:04:10 1:54:25 14.54:12 20:44:14 2:34:17 8:24:19 14-14:21 20:04:23 The DEGB test also included a flow reduction sequence which represented removal of one pump from service at a time, followed by returning flow to the equivalent 100% value, then increasing debris to 120%, and then increasing flow to 120%.

Attachment 3 to AEP:NRC:8054-02 Page 214 The limiting debris head loss case for the DGBS was determined to be an event sequence test, designated as Test T2121-6, that used homogeneous debris mixtures.

This test was intended to mimic the sequence of events that would occur in the plant following a LOCA. For this test, the remote strainer inlets were blocked off and flow was initiated through the remote strainer at approximately 75% of the flow rate that was calculated by the debris transport analysis (Reference

28) to occur through the main strainer during pool fill. With this flow rate established, the quantity of debris determined to be transported to the main strainer during pool fill was added to the main strainer side of the test strainer.

After 30 minutes, the flow rate was increased to 100% of the calculated pool fill flow rate through the main strainer.

This flow rate was maintained for 15 minutes. After this time period, the blanking plate was removed from the remote strainer side of the test strainer, and the 100% quantity of debris determined to be transported to remote strainer, and the difference in debris quantity between the pool fill value and the 100% value for the main strainer was added to the respective sides of the strainer.Also, the flow rate was increased to 50% of the total flow rate to represent the alignment of the first train of ECCS and CTS pumps to the recirculation sump. These last steps (removal of blanking plate, addition of debris, and increase of flow rate) were accomplished as simultaneously as possible.

Approximately five minutes after these actions were completed, the flow rate was increased to 100% of the total flow rate to represent the final alignment in which both trains of ECCS and CTS take suction from the recirculation sump. The highest head loss achieved during this test was 7.2 in H 2 0 approximately 3 3/4 hours after reaching 100% flow. At the end of the test, the head loss was at approximately 7.0 in H 2 0 and decreasing slowly. The head loss values provided are the 20 0 C normalized values. Figure 3f10-2, below, provided the plot for this test.Figure 3f10-2 DGBS Event Sequence Head Loss Test Plot 12502 1 500 ~2 Pool °C 17 0-6 nU 10004I 75O0 4 ,o!250-o7 3 0 8:3935 9.19.36 9:59.36 10:39:36 11.19.36 11:59.37 1239.37 13:19:37 Attachment 3 to AEP:NRC:8054-02 Page 215 With the limiting debris only head loss cases established for the DEGB and DGBS, the determination of the overall system head loss is necessary.

As discussed in the response to Information Item 3.f.9, there were two methods used to determine the overall system head loss.One method was documented in an I&M calculation (reference 142), and the other method was documented in a CCI calculation (Reference 143). To provide an understanding of these two methods, the applicable text in Reference 142 and Reference 143 has been excerpted and presented below.I&M Calculation The method used in the I&M calculation was described specifically for each test case. The descriptive text from Reference 142 on of the method used for Test Case 2121-3 is as follows:

Attachment 3 to AEP:NRC:8054-02 Page 216 5.3 Test Case 2121-3 Test Case 2121-3 measured and recorded the head loss for the strainer system test configuration with reflective metal insulation (RMI) and "Loop 4 Break -Maximum Particulate Debris (DEGB)". The RMI and DEGB debris are characterized in Reference 10.1.5.3.1 Determine Test Case 2121-3 Open Strainer Areas and Head Losses for the Main and Remote Strainers The head loss for the strainer system test configuration for Test Case 2121-3 is: hLca.je3 11.317in Design Input 3.3 ,,al .f Test achieved 100% of the design flow. Qd I i00% 00 , or Qd -i 32.083-rm 3' 8 see the test was scaled to a factor of 1 :41.From the test report Qd Design Inputs 3.6 and 3.7 Ot SF fl3 Qj 0.783-see From test data RatioCase3Av gRSAvg,\S z !.C43 From the definition of the Ratio.AvgRSAvgMS:

Qrs3 Qrs3 -= RQ 1 i°Case3AvgRS,A 1 3 S'Qms3 Design Input 3.3+RaroC ase Attachment 3 to AEPNRC:8054-02 Page 217 Qd'SF= 0.783- Qt+ RafbCaie3AvgRSPAvVANS Qrns3 ft 3 QmO3 Sec Qrs3 Qt Ofi -ti.0 Qr3 -0.486-f Ste K-factors for the main .and remote strainers were calculated for the test configuration in Section 5.1.1 Kmsi =2491.19 Krsi =` 20 1-056 Determine strainer area and head losslfor the strainer system test configuration using the Mathcad Solver Block..Enter guess values for the n unknowns.Ares3:= ;5ft 2 A 3 s 3 5f2.hLn3 := I ft hLrs3 := Ift Attachment 3 to AEP:NRC:8054-02 Page 218 Write n equations for n unknowns, and use Mathcad Solver Block to ca~lculate the solution.Given:2 hLino n3-,3 ;2.hL~s3rs hLIKm3 = ILs3 hLcase3 -he 1 m 1 3 hLrm 3 Find the solution: veC.-zrFind{

Am-ts3 "ý-isv 1 Lms3 hLiS3.)Solufion: 1,34lft2 vee = .98ft-1.88ISftT I 86fi I Attachment 3 to AEP:NRC:8054-02 Page 219 Write the solution to the unknowns: 0AtfLO'3 1 341 f v"NO 1.98 ""2 hLnus386 = 1.6ft UL'S3 Vec3 hLr 3 ý 1,886 ft Check head loss against the test data for reasonableness.

1 hLnms3 hLrs3 hL-cae3 7,11.317 in Checks okay with the test data.( {Qms3'2 2g ILM&3 1,886ft Checks okay with the solution.

Attachment 3 to AEP:NRC:8054-02 Page 220 5.3.2 Determine the Strainer System Head Loss Based on Case 2121-3 for the Actual Configuration Use the main and remote strainer areas (i.e., open strainer area) calculated in Section 5.3.1 to determine the head: loss for the strainer system actual configuration.

Known Values: 14400 Srain Qd SF' Design Inputs 3-6 and 3.7 K 1.85 Kdct3-Design Input 3.13 K-factors for the main and remote strainers were calculated for the test configuration in Section 5.1. 1.KmsI = 2491.19 Knil 7 201L056 5. 727fC Design Input 3.10 Area of strainers were determined by strainer area that remained open from Test Case 2121-3 data reduction in Section 5.3.1.1.341 fl 2 Ars3 -1 98 ft2 Determine the flow through the main and remote strainers considering the additional head loss due the duct being in series with the remote strainer.

Flow represents three of the unknowns (iQe., Qms 0Q, Qduc 4.- The unknown flows also result in unknown head losses for the main and remote strainers, and the duct (hm, hLm, htduct). The last unknown is the overall strainer system head loss for the actual configuration (i.e., hLsyS).

Attachment 3 to AEP:NRC:8054-02 Page 221 Use the Mathcad Solve Block to solve the nonlinear system of equations that can be written for the strainer system configuration.

Enter n guess values for the n unknowns.hLsyS3 0O. 1 ft'7 " rO t f3 Qms3 :z 20.SLC Qrs-31 20 -see-fi 3 Qduct3 '=20 41" hLdC,3 := 0, 10ft Write n equations for n unknowns, and use Mathcad Solver Block to calculate the solution.Given h 1 Lsys.3 -Shn L3 hrL3 + hLdc 0 rnQs3 "i 22 A= k~~~5 i ns3=KtSv3 I g Attachment 3 to AEP:NRC:8054-02 Page 222 S41Qdud3 hLd=L3 = KducL3 9" Q rs3 = Odtc O hLa.3-hLrt3 4 hLduct3 Find the solution: '¢ ec Fi,'td(Q ns 3 , Q N3. ddit"h m 3 hLrs3 , hLduct3 , h L~v .,3)Solution: 0312- I 0,47-t.e Vec 0,471 gee 2.09f'rt: 1.766ftl 03,6.ft 1.046rt Attachment 3 to AEP:NRC:8054-02 Page 223 Write the solution to the unknowns: Qts3 m 139.968 -al rai vet ~ r3. 21.25 -3.fllsale SF es 0 nOs3.futl.szae

= SF.QmS3 QvO3 :m vecI Qrs,3 = 211,251 min '),s3S.fsade

- SFýQrsi rat Qduct3 :2= vet 2 21,25 1 L Qduct3.fudlicale

= SF.Qduc3 (ýd= Qdut3- millSFQd.n hLnI3 3 LmO = 2,092 ft h Ln3 = 25.107 in"Lrs3 := vet 4 hL,,,3 = hLrs3 = 21A39in hLdtct3 ve5 c Ld uct3 ý 0.326fi hLduct3 13917in ShLsysi :e, hLsVS3 1 1046 II hLsvs3 12.553 ift Note that the full scale flow is SF (e.g., 41) times the calculated test flow.Check the solution for reasonableness.

Qms3,Thllsc-Qe m5738.699-.---

mill min QAuc.nulfscale

= 8661.301 -raii RatioCae3AvgRsS.A

= 1 643 Qrs 3 The ratio (Q0 , Qms) was reduced from1f64 to 1.5 due to additional duct= 1.509 head loss in series with the remote strainer.

This reduction is expected.Thus, the strainer system head loss at the design flow of 14400 galtmin for Case 2121-3 reconciled to the actual configuration is ht-ws3.hLl-sys, 12,553 in. h1L~v3 = 1. 46 ft Attachment 3 to AEP:NRC:8054-02 Page 224 CCI Calculation The method used in the CCI calculation provided the framework for making the determinations and then provided the results in tabular form. The descriptive text from Reference 143 on the method used for Test Case 2121-3, DEGB with all debris, is provided below.6.3 System head losses The system head losses are derived here for the conditions of the large size strainer tests performed in the university hydraulics pool.Since the large size testing had negligible clean pocket head losses, the measured head losses are just debris layer head losses for practical purposes.

Since the flow through a debris layer is laminar, the head loss is a linear function of the flow velocity through the screen, and we can write: HLd,ms = Kms * (FRms / Ams), HLd,rs = Krs * (FRrs / Ars), Where HL = head loss (ft WC), including chemical bump-up factor, FR = flow rate (m3/s), A= screen area (ft2), index ms = main strainer, index rs = remote strainer, d = debris.We can determine the Kms and Krs for each tested condition, since all other values are known from the tests.For the system head losses, we can set up the following 4 equations:

(1) HLms = HLc,ms + HLd,ms = Kc * (FRms/Ams)A2

+ Kms * (FRms/Ams)

(2) HLrs = HLc,rs + HLd,r§ + HLd = Kc * (FRrs/Ars)A2

+ Krs * (FRrs/Ars)

+ Kd

FRrsA2 (3) HLms = HLrs (4) FRtot = FRms + MRrs or FRms = FRtot -MRrs Equating (1) and (2) according to (3), and substituting FRms from (4), we get a quadratic equation with the only unknown FRrs as follows Kc * ((FRtot-FRrs)/Ams)A2

+ Kms * (FRtot-FRrs)/Ams

= Kc * (FRrs/Ars)A2

+ Krs * (FRrs/Ars)

+ Kd

FRrsA2 Rearranging on the right hand side yields FRrsA2 * (Kc/ArsA2+Kd-Kc/AmsA2)

+ FRrs * (Krs/Ars+Kms/Ams+2*Kc*FRtot/AmsA2)+

(- FRtotA2 *Kc/AmsA2

-FRtot

Kms/Ams) = 0 Attachment 3 to AEP:NRC:8054-02 Page 225 This equation can be solved for the basic quadratic equation xA2

a + x

b + c = 0 as follows (x being FRrs) : X = -b/(2*a) + SQRT (bA2/(4*aA2)

-c/a)Equation [4] then yields the value of FRms. Then, with equations (1) or (2), the system head losses can be calculated, and should yield the same value.

Attachment 3 to AEP:NRC:8054-02 Page 226 The following table contains the whole calculation for the large size Test Case #4 (T2121-3).

Derivation of Test K-factors for Debris Derivation of S stem Head Losses Test FRtot Ams Ars No. m3/s ft2 ft2 4 0.9084 1.347 87033 850 1000 b Mrs m3/s FMrs m3/s HLms ftwc=HLrs ftwc 1.3136 5.153539 -2.8643 0.493669 0.41473062 1.2830232 1.2830232 The head loss value calculated is not temperature corrected, but does include the "bump-up factor" (identified in NRC Requested Information Item 3.o.15) determined for chemical effects. Removing this bump-up factor results in a calculated debris only system head loss of 0.9 ft H 2 0, normalized to 20 0 C.

Attachment 3 to AEP:NRC:8054-02 Page 227 As shown above, the two approaches shown for determining system head loss produced differing results. To ensure the determined maximum strainer head loss is appropriately bounded, the calculated head loss determined by the I&M method will be increased by 50% for both the DEGB and DGBS cases. This will ensure uncertainty is bounded and will also provide margin. For the DEGB case, the assumed maximum debris only head loss will be 1.57 ft H 2 0. This provides a margin of 0.524 ft H 2 0 to the calculated system head loss based on strainer testing. For the DGBS case, the assumed maximum debris only head loss will be 1.23 ft H 2 0. This provides a margin of 0.41 ft H 2 0 to the calculated system head loss based on strainer testing.The response to this information item has focused on the test results that provided the maximum debris-only head loss. Refer to the response to Information Item 3.f.4 for the discussion of other tests that were performed and their results.I&M Response to Information Item 3.f. I As previously described in the responses to Information Items 3.f.3 and 3.f.7, the CNP recirculation sump design is a fully vented design. Figure A4-1, in Attachment 4, provides a cross-section view of the recirculation sump configuration.

For purposes of establishing the maximum allowable head loss across the strainer, I&M is using the guidance from NUREG/CR-6808 that limits the maximum head loss across the strainer to one-half of the available pool height. For CNP, the limit for water level inside the recirculation sump is based on vortexing, not NPSH, as described in the response to Information Item 3.f.3. As described in the response to Information Item 3.k.2, the main and remote strainers are qualified for a head loss of 15 ft which bounds the maximum flood-up elevation in containment assuming a strainer is fully blocked with debris.I&M Response to Information Item 3.f.12 I&M did not take any credit for near-field settling.

For testing in the CCI test facilities, both the large scale test loop in Winterthur, Switzerland, and the CCI MFTL, the debris is added just upstream of the strainer elements to maximize the debris ingestion into the strainer pockets. Based on the debris transport CFD analysis that was performed for the worst case break (RCS Loop 4 Crossover Leg DEGB), the flow distribution in the vicinity of the main strainer does not show a flow field that would appear to support significant settling of smaller debris. For the remote strainer, the flow field could result in settling of debris. Refer to Figure 3f12-1, below, for the flow velocity illustration reviewed for this assessment.

However, no credit is being taken for near field settling of fine debris and testing was conducted in manner intended to preclude near-field settling.

Attachment 3 to AEP:NRC:8054-02 Page 228 Figure 3f12-1 Vectors Showing Po Direction for Loop 4 Break 2007-11-21 DC Cook Task 1 Loop 4 90% Blocked unlLvectors.bmp The main and remote strainers are in the lower right hand quadrant of the figure.I&M Response to Information Item 3.f.13 I&M did not scale the results of the head loss testing to expected plant pool temperature.

Since CNP is an ice condenser plant, the pool temperature is substantially lower than the temperature experienced in large dry containments.

This is due to the ice melt from the ice condenser.

The lowest expected temperature for the containment pool is 80OF (Reference 25).

Attachment 3 to AEP:NRC:8054-02 Page 229 I&M Response to Information Item 3.f.14 I&M did not credit containment accident pressure for any aspect of resolving the issues associated with GL 2004-02. Since the CNP recirculation sump is a fully vented design, the atmospheric pressure inside the recirculation sump is the same as the pressure outside the sump.

Attachment 3 to AEP:NRC:8054-02 Page 230 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.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.g.1 The ECCS and CTS each include two trains of pumps. Each ECCS train consists of one high head CCP, one intermediate head SI pump, and one low head RHR pump. Each CTS train also includes a single containment spray pump. The CCPs are normally aligned to the VCT providing normal charging and seal injection to the RCS and RCPs. The remaining pumps are normally aligned to the RWST. The CC, SI, and RHR pumps are started either automatically based on SIS actuation logic, or manually.

Upon actuation of an SI signal, the suction of the CCPs automatically realigns from the VCT to the RWST. The CTS pumps are started by either containment spray actuation logic, or manually.

Attachment 3 to AEP:NRC:8054-02 Page 231 The ECCS and CTS pumps are aligned to the containment recirculation sump by manual operator action once a pre-determined minimum RWST level has been reached. Following completion of switchover to recirculation, the RHR and CTS pumps take suction directly from the containment recirculation sump. The SI pump and CCP suctions are each aligned to the discharge of their train-specific RHR pumps.The pump flow rates associated with the minimum NPSH margin cases for each individual pump which takes suction from the containment recirculation sump are shown in Table 3g1-1.Table 3g1-1 Recirculation Minimum NPSH Cases -Individual Pump Flow Rates Pump Unit 1 Unit 2 West RHR 4093 gpm (1) 4175 gpm (1)East RHR 4047 gpm (1) 4173 gpm (1)West CTS 3251 gpm 3253 gpm East CTS 3279 gpm 3281 gpm (1)_ Failure of opposite RHR pump assumed with running pump supplying two SI pumps and two CCPs.The maximum assumed flow for two-pump operation of the RHR pumps is 3800 gpm per pump.The maximum assumed flow for two-pump operation of the CTS pumps during recirculation is 3400 gpm per pump. Therefore, a maximum/bounding recirculation sump flow of 14400 gpm was utilized for hydraulic and head loss analysis associated with resolution of GL 2004-02. The assumed RHR pump flows for sump recirculation assume both pumps are in-service which results in a higher total flow rate and resulting head loss across the strainer.

The maximum flow case for the CTS pumps for NPSH considerations, provided in Table 3g1-1, above, is conservatively less than that assumed for sump strainer head loss considerations.

During recirculation mode, the SI pumps and CCPs operate in piggyback mode with their suction aligned to the discharge of the RHR pumps. Therefore, the limiting NPSH for these pumps is during the injection mode when these pumps take their suction from the RWST.The containment recirculation sump temperature assumed in the NPSH analysis for recirculation flow is 190'F.The containment water level assumed in the NPSH analyses is 602 ft 10 in, which is-approximately 4 ft above the containment floor. The minimum containment water level calculated for a LBLOCA is 5.9 ft above the floor at 9.1 hours1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months after the initiation of the event.The minimum containment water level calculated for a 2 in SBLOCA is 5.1 ft above the floor at approximately 10 hours1.157407e-4 days 0.00278 hours 1.653439e-5 weeks 3.805e-6 months after the initiation of the event.I&M Response to NRC Information Item 3.q.2 I&M has performed calculations for the ECCS and CTS pumps during the recirculation phase for determination of NPSH margin. A series of hydraulic cases were evaluated including various combinations of pump performance curves, failure of an RHR pump and minimum containment water level. ECCS pumps were assumed to be operating at their maximum pump curves during Attachment 3 to AEP:NRC:8054-02 Page 232 the recirculation phase. From these cases, the bounding case for each pump was selected based on the lowest NPSH margin (References 37 and 38).The sump temperature utilized in the NPSH analysis is 190'F, as provided in UFSAR Sections 6.1 and 6.3.2, and Table 6.1-1. This temperature corresponds to the initial and maximum sump temperature, and is therefore conservative.

The containment water level used in the NPSH analyses is 602 ft 10 in, as provided in the UFSAR Section 6.3.2, which is approximately 4 ft above the containment floor. This water level was established during licensing of CNP Unit 2 by assuming water inventories available without credit for ice melt.The bounding NPSH cases for the RHR and CTS pumps when taking suction from the recirculation sump is determined assuming the failure of an RHR pump (single failure assumption) with the remaining RHR pump supplying two trains of ECCS (two SI pumps and two CCPs). The basis for this approach is to maximize flow through the single operating RHR pump and to minimize the available NPSH (References 37 and 38).I&M Response to NRC Information Item 3.gq.3 The required NPSH values are specified by the individual pump manufacturers, and are shown on the certified pump performance curves. Pump manufactures typically set the required NPSH using a test loop where pressure is lowered in the suction source until a drop of 3% of the total head is measured.

The available NPSH at which the 3% head drop occurs is then defined as the required NPSH for that flow. This method of required NPSH determination is used unless an alternate method was specified by the customer.

Since I&M did not specify an alternate method to calculate required NPSH, it is assumed that the 3% head drop method was utilized.I&M Response to NRC Information Item 3.g.4 Friction and other losses are determined by the use of the Proto-FIoTM hydraulic analysis code.This code determines friction and line losses of the system by using the physical description of the system (pipe lengths, number of elbows and fittings, junction points, etc.) and the operating mode (pump status, valve line-up, boundary pressure conditions, etc.). Suction line head losses include entrance losses and friction losses through pipe, valves and fittings associated with the ECCS or CTS pump being evaluated.

Head losses considered include friction losses based on pipe roughness, pipe length, velocity head losses, sump outlet pipe head losses and the number and type of valves, and fittings in the suction piping. In addition to these parameters, component differential pressures (heat exchangers, strainers, etc) at a given flow rate are utilized to determine the losses at another flow rate. The code utilizes the Bernoulli Equation and the Darcy-Weisbach Equation as a means of determining the friction losses.I&M Response to NRC Information Item 3.gq.5 The system response scenario for a LBLOCA begins with a complete depressurization of the RCS. This depressurization results in the initiation of a reactor trip and SI actuation signal.Containment pressure rapidly increases resulting in a containment spray actuation signal. The CC, SI, and RHR pumps receive a start signal from the SI actuation signal and begin'injection Attachment 3 to AEP:NRC:8054-02 Page 233 into the RCS cold legs from the RWST. The CCP that was aligned to the VCT automatically realigns to take its suction from the RWST. The CTS pumps start on the containment spray actuation signal, taking suction from the RWST, and discharging to the CTS headers in upper containment, loop compartment, and annulus. The SAT contents (sodium hydroxide) are transferred to CTS via eductors in the tank outlet lines.As containment pressure starts to increase from the break, the ice condenser lower inlet doors (48) would open admitting non-condensable gases and steam into the ice condenser, initiating ice melt. The ice condenser lower inlet doors are held closed only by the cold head of air that exists inside the ice condenser.

Additionally, when lower containment pressure increases above a nominal 1.1 psig, the CEQ fans receive a start signal, circulating air through containment, including forcing flow through the ice condenser.

Once RWST level is less than 20% (approximately 18 to 20 minutes from start of event), and containment water level is confirmed to be above 602 ft 10 in, the manual switchover to the recirculation mode begins. The water level at this point is calculated to be 7.7 ft above the containment floor. The manual switchover sequence involves stopping the east train RHR and CTS pump, then initiating closure-of their suction isolation valves (from the RWST). The west train RHR and CTS pumps are then stopped and their suction isolation valves are given a close signal. Once the east train pumps' suction isolation valves are closed, the east train recirculation sump isolation valve is opened. When the valve is full open, the east train RHR and CTS pumps are restarted.

When the west train RHR and CTS pumps' suction isolation valves are closed, the west train recirculation sump isolation valve is opened. When the valve is full open, the west train RHR and CTS pumps are restarted.

The next steps in the sequence are to reset the containment spray actuation signal and close the motor-operated SAT outlet valves and eductor supply valves, terminating sodium hydroxide addition to containment.

When RWST level decreases to less than 11%, the SI pump discharge crosstie valves are closed. The SI pump recirculation valves and the CCP leakoff valves are then closed. The east and west train RHR supply valves to the CCPs and SI pumps are then opened, and the crosstie valves between these two lines are then opened. Once the realignment to the piggyback mode is complete, the RWST outlet isolation valve and the CC and SI pumps' RWST suction isolation valves are closed.If only one CTS pump had started, and at least one CC and SI pump were operating, and at least 50 min had elapsed since event initiation, then one train of RHR spray to upper containment would be initiated.

This is accomplished by closing the RHR injection valve to the RCS and opening the RHR spray to containment valve.For the SBLOCA, since the GR and SER do not require consideration of breaks less than 2 in, the response to the break would be similar to the LBLOCA. For the 2 in break, the pressurizer is not expected to refill following the break, but the time for RCS pressure to decrease below the shutoff head of the RHR pumps would be slightly extended.

This would extend the time to recirculation.

The most significant difference for a break of this size would be the reduction in the initial containment peak pressure that would occur and the extended time to melt out the ice bed. As discussed in the response to Information Item 3.f.4, the minimum sump water level Attachment 3 to AEP:NRC:8054-02 Page 234 would be lower for a break of this size, but still over a foot above the minimum water level assumed for the NPSH available calculation.

For both scenarios, the EOPs currently stop CTS pumps when containment pressure drops below 2 psig. This recirculation sump flow reduction would occur sooner for-the SBLOCA than the LBLOCA.I&M ResDonse to NRC Information Item 3..q.6 Prior to the initiating event, the ECCS and CTS pumps will be in a state of stand-by readiness, with the exception of one CCP which is normally aligned for RCS charging.

The remaining seven ECCS and CTS pumps start in response to reaching the SI and containment spray setpoints.

Each of these pumps takes its suction direct from the RWST during the injection phase, Following realignment to recirculation (refer to the response to Information Item 3.g.5), each train of RHR and CTS pumps are taking suction from the recirculation sump through train specific suction piping. The SI pumps and CCPs are aligned to receive their suction from the discharge of the associated RHR train's heat exchanger.

In the event that both CTS pumps are not available after the initial 50 minutes, and at least one CC and SI pump are running,-

an operating RHR pump is realigned to provide upper containment spray in addition to supplying the operating CC and SI pump.I&M ResDonse to NRC Information Item 3.g.7 The limiting single failure assumption relevant to pump operation is the failure of one RHR pump. This assumption results in the remaining operating pump supplying two trains of ECCS (two SI pumps and two CCPs). This assumption then allows the determination of maximum RHR pump flow and minimum NPSH available.

Per CNP's UFSAR (Section 14.3.1.2), the limiting single failure for core and containment cooling is the loss of an entire train of ECCS and CTS. In the event that only a single train operated following a DEGB LOCA, the head loss across the strainer would not result in a challenge to the head loss limit since the flow rate would only be approximately 50% of tested equivalent flow rate.. Testing performed at CCI determined that for a 23.6% reduction in flow, the corresponding reduction in debris-only head loss across the strainer was approximately 38%. For a 47.2%reduction in flow, the corresponding reduction in debris only head loss across the strainer was approximately 66%. CNP's licensing basis for single failure criteria (UFSAR Sections 1.4.7 -Criterion 41, 6.2.1, 6.2.3, Table 6.2-6, and Table 6.2-7) assumes an active failure during the injection phase, or an active or passive failure during the recirculation phase. For sump inventory analysis, the assumed limiting single failure is the failure of one of the two CEQ fans.If this failure is not assumed, the resulting minimum containment water level would be higher than is currently assumed. This would result in a greater allowable head loss across the strainer.I&M ResDonse to NRC Information Item 3.g.8 The containment recirculation sump water level was determined via an inventory analysis which was submitted to the NRC and subsequently approved by the NRC (Reference 32).

Attachment 3 to AEP:NRC:8054-02 Page 235 As described in Reference 32, containment recirculation sump water level was determined via an analysis which evaluated the containment sump level history for postulated LOCA conditions, including the injection phase, the transfer from injection to recirculation, and the recirculation phase. The MAAP4 code was used for this analysis since it provides an integrated evaluation of the RCS and containment response.

Both the RCS and containment were considered since the water inventory in the sump is influenced by:* the RWST injection and containment spray,* the melted ice condenser ice mass,* the holdup in the RCS and other piping systems,* the holdup in containment,* the extent of accumulator injection, and* the water flow between containment compartments.

A complete spectrum of RCS break sizes was evaluated for Mode 1 conditions beginning with the DECL break and including all break sizes which are sufficient to initiate containment sprays (1/2 in). In addition, the analysis also considered postulated breaks associated with MODE 3-operations, and below, -with the initial RCS temperature at 350 0 F. The operator actions associated with establishing recirculation and RCS cooldown were also included in the analysis.Furthermore, as a conservatism, this analysis considered plant conditions that were judged to be the most limiting in terms of the mass of ice melted since this water inventory is added to the containment sump and is an important element of the sump water level determination.

This analysis also considered different system configurations, such as one train of ECCS/safeguards operating and two trains performing with an individual single failure. A FMEA was performed to determine the most limiting condition(s) related to the containment sump inventory under the spectrum of LOCA conditions evaluated.

Since ice melt inventory was part of the containment sump evaluation, the FMEA conditions were directed toward minimizing the extent of ice melt with the particular focus being the lowest spray temperatures which produce the maximum steam condensation, i.e., minimize the ice melt. Specifically, these related to the minimum RWST temperature and the minimum ultimate heat sink temperature that was providing cooling water for the CCW systems. In all aspects of this analysis, the potential variables were considered in a direction that would minimize the quantity of water available in the post-LOCA containment.

I&M Response to NRC Information Item 3..q.9 The assumptions contained in the containment water level analysis (Reference

32) were based on a FMEA to determine the most limiting conditions relevant to the containment sump inventory under a spectrum of conditions.

Since the ice melt inventory is part of the containment sump evaluation, the FMEA conditions were directed toward minimizing the extent of ice melt with the particular focus being the lowest containment spray temperatures, which produce the maximum steam condensation, i.e., minimize the ice melt. Specifically, those relate to the minimum RWST temperature (based on the minimum TS limit) and the minimum lake temperature that is the cooling water for the ESW system. In addition, other elements of the containment analysis resulted in containment sprays being initiated at the earliest time in the accident.

The results of the FMEA analysis included:

Attachment 3 to AEP:NRC:8054-02 Page 236* RWST temperature of 70'F" Initial containment pressure 15 psia" Initial containment temperature in all compartments 60°F (minimizes the steam partial pressure to be condensed)

Lake water temperature used for ESW system was 33 0 F* CCW heat exchanger inlet temperature is 60'F* Initiation signal including uncertainty for the CEQ fans start was 0.5 psig* Setpoint including uncertainty for initiation of containment sprays was 2.3 psig Additionally, several conservatisms were included in the water level analysis.The free volumes in the analysis represent total volumes of the pipe annulus and lower compartment and no assessment was made for the volume occupied by internal structures such as pipes, valves, etc. Not including an allowance for the displacement of liquid volume is a conservatism in the current water level analysis.The SAT inventory (approximately 5,000 gals) was not included in the sump inventory, which represents a conservatism in the current water level analysis.The mass and energy releases to the containment were provided by the MAAP4 code using the assumption that the steam and water discharged from the break were in thermodymanic equilibrium.

This resulted in the maximum water enthalpy and therefore the minimum steam, mass produced as the mixture flashes into the containment.

Therefore, the use of the MAAP4 mass and energy releases produced the minimal ice melt for a given break size which represents a conservatism in the current water level analysis.As provided in the response to Information Item 3.g.2, the minimum water level assumed for NPSH availablewas established at 602 ft 10 in during the licensing of CNP Unit 2. This value was the level in containment, determined at that time, that did not include any ice melt contribution.

I&M Response to NRC Information Item 3.g.10 The containment sump water level analysis (Reference

32) included conservative determination of holdup or unavailable water volumes. The water holdup evaluation included determining the volume of water in the spray piping, the airborne spray water in the containment, film drainage on the containment walls, holdup on horizontal surfaces such as the top of the SG enclosures in upper containment, and areas where water would be trapped and unavailable for sump inventory.

The spray piping holdup volume was determined by summing the volumes of the respective piping configurations.

Airborne spray was determined by calculating the spray fall height in respective compartments and then multiplying the spray flow in each compartment by the fall height, and then dividing by the terminal velocity of the droplets.

Film drainage on containment walls was determined by determining the average film thickness and applying this thickness to the various wall areas on the containment compartments.

Additionally, a water holdup of 9500 gals was assumed for the refueling cavity. The volume transferred from the RWST was based on the minimum RWST volume required by the TSs, and considered the Attachment 3 to AEP:NRC:8054-02 Page 237 timing of operator actions to transfer the suction of the ECCS and CTS pumps from the RWST to the recirculation sump.I&M Response to NRC Information Item 3.g.11 The sump inventory analysis (Reference

32) utilized the total volumes of the various containment compartments and no assessment was made for the volume occupied by internal structures such as pipes, valves, and equipment.

This approach yielded conservative results since internal structures occupy volume and would result in a higher water level.I&M Response to NRC Information Item 3.ci.12 From Reference 32, the water sources providing pool volume included the following:

An RWST volume of 297,900 gals was assumed transferred to the RCS and containment, which includes 314,000 gallons taken from the RWST minus 16,100 gallons assumed as holdup volume (refer to the response to Information Item 3.g.10).An ice mass of 2.11 x 106 Ibm (253,089 gallons) was assumed transferred to the containment sump. This value corresponded to the TS required minimum ice mass for each unit. The modeling of the ice condenser drainage included a small holdup on the ice condenser floor. It should be noted that the analysis did not immediately provide this quantity of ice melt. Since the analysis was biased toward minimizing ice melt, the total volume of ice melt was not reached prior to the termination of the analysis.An accumulator volume of 27,618 gallons was assumed transferred to the containment sump based on the TS required minimum volume for each accumulator.

Approximately half of the RCS volume is transferred to the containment sump since the RCS volume cannot be refilled for a large break. This was approximately 41,700 gallons.I&M Response to NRC Information Item 3.q.13 No credit is taken for containment pressure in determining NPSH available.

The NPSH analysis assumes a containment pressure of -1.5 psig, the lowest pressure allowed by TSs.I&M Response to NRC Information Item 3.q.14 The NPSH calculation conservatively utilizes a containment pressure of -1.5 psig, which corresponds to the minimum pressure allowed by the Technical Specifications.

The sump temperature utilized in the NPSH analysis is 190 0 F. This temperature corresponds to the initial and maximum sump temperature, and is therefore conservative.

The containment sump pool temperature quickly reduces from this temperature as a function of ice melt, providing additional NPSH margin.

Attachment 3 to AEP:NRC:8054-02 Page 238 I&M ResDonse to NRC Information Item 3.g.15 The containment accident pressure is not set to the vapor pressure corresponding to the sump liquid temperature.

No credit is taken for containment overpressure.

The containment pressure is set to -1.5 psig in determining available NPSH, which is the minimum pressure allowed by the TSs.I&M Response to NRC Information Item 3.q.16 Table 3g16-1 provides the NPSH margins for the RHR and CTS pumps which take suction from the recirculation sump.Table 3g16-1 NPSH Margins for RHR and CTS Pumps in Recirculation Mode Pump Flow NPSHa NPSHr Margin Unit 1 West RHR 4093 gpm 27.6 ft abs 16.6 ft abs 11.0 ft abs East RHR 4047 gpm 30.7 ft abs 16.3 ft abs 14.4 ft abs West CTS- 3251 gpm 28.1 ft abs 14.0 ft abs 14.1 ft abs East CTS 3279 gpm 29.1 ft abs 14.1 ft abs 15.0 ft abs Unit 2 West RHR 4175 gpm 26.6 ft abs 17.1 ft abs 9.5 ft abs East RHR 4173 gpm 30.5 ft abs 17.0 ft abs 13.5 ft abs West CTS 3253 gpm 28.5 ft abs 14.0 ft abs 14.5 ft abs East CTS 3281 gpm 29.5 ft abs 14.1 ft abs 15.4 ft abs I&M will provide an update to the calculated NPSH margins following completion of analysis associated with determination of head loss across the strainer, including chemical effects. This update will be provided per the schedule contained in the response to Information Item 2.

Attachment 3 to AEP:NRC:8054-02 Page 239 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, i.e., 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.1 At the time of initial construction of CNP Unit 1 and Unit 2, the specified coating systems for containment application were as follows.* Concrete Surfaces -Carboline 195 surfacer with Carboline Phenoline 305 primer/top coat. The total DFT for this system was specified as 15 mils.* Steel Surfaces -Carboline Carbo Zinc 11 primer with Carboline Phenoline 305 top coat.The total DFT for this system was specified as 8 mils.During the extended shutdown of CNP Unit 1 and Unit 2 from 1997 to 2000, a significant effort was undertaken to recoat containment interior surfaces.

During this effort, essentially all surfaces in lower containment were recoated as well as accessible areas of the containment liner, floor surfaces, and portions of the dome in upper containment.

The walls and floors associated with the SG enclosures were recoated following SG replacements in 1989 (Unit 2)and 1999 (Unit 1). The coating systems used during the 1989.SG replacement were the same'as the initial coating systems described above. The coating systems used during the extended shutdown were as follows.* Concrete Surfaces -Carboline Starglaze 2011S with Carboline 890 primer/top coat.The total DFT for this system was specified as 4.5 to 12 mils.* Steel Surfaces -Carboline 890 primer and top coat. The total DFT for this system was specified as 3 to 12 mils.The current requirements for the coating systems DFT are the same as those listed above for the extended shutdown.

Attachment 3 to AEP:NRC:8054-02 Page 240 CNP has not developed a calculation to estimate the total qualified coating surfaces in containment.

For the determination of those qualified coating systems within a ZOI, and the unqualified coatings in containment, see the response to Information Items 3.h.5 and 3.h.6.I The types of unqualified coatings in CNP Unit 1 and Unit 2 containments is provided in the response to Information Items 3.h.5 and 3.h.6.I&M Response to Information Item 3.h.2 The debris transport analysis included the following assumptions with regard to post-LOCA paint debris transport.

The unqualified coatings and other miscellaneous unqualified debris types outside the ZOI were assumed to fail during recirculation.

This is a reasonable assumption since this debris is outside the ZOI and would fail gradually.

Based on this assumption, the unqualified debris in upper containment would be distributed in the vicinity of. the refueling canal drains (where the majority of the upper containment spray would enter the recirculation pool), the unqualified debris in the annulus was assumed to be uniformly distributed in the annulus, and the unqualified debris in the loop compartment was assumed to be uniformly distributed in the loop compartment.

Coatings material that is dislodged during the blowdown from a pipe break is not retained by equipment or structural elements within containment and would be available for transport.

It was assumed that the fines generated by the LOCA blast would be distributed to the ice condenser, annulus, and reactor cavity in proportion to the blowdown flow split arrived at in the TMD analysis (Reference 94). This is a reasonable assumption since fine debris generated by the LOCA jet would be easily entrained and carried with the blowdown flow. As a result, 8% of the coatings material (fine. particulate) generated-within the ZOI were assumed to be transported to the reactor cavity, an inactive volume." Unqualified coatings in upper containment and the annulus were assumed to be washed down with containment spray. Coatings debris that is blown into the ice condenser during the blowdown were assumed to be washed down to the loop compartment with the ice melt. These coating materials were assumed to reside in the containment pool at the initiation of recirculation.

It was assumed that the settling velocity of fine debris (insulation, dirt and dust, and paint particulate) could be calculated using Stokes' Law. This is a reasonable assumption since the particulate debris is generally spherical and would settle slowly, which is within the applicability of Stokes' Law.* The settling velocity and TKE required to keep the 10 micron paint particulate in suspension was calculated in the same manner as was the settling velocity for dirt and dust. For larger particulates, the settling velocity was high enough that it was outside the Attachment 3 to AEP:NRC:8054-02 Page 241 range of Stokes' Law. Therefore, the settling velocity for larger particulates was calculated using a standalone CFD simulation.

The unqualified coatings debris that is assumed to fail as chips at CNP includes the unqualified epoxy (4 mils thick, 94 Ib Vft 3) and unqualified alkyd (4 mils thick, 98 lbm/ft 3)paint. For this analysis, the alkyd chips were conservatively assumed to be transported in a similar manner as unqualified paint particulate.

The settling and tumbling velocity metrics for the epoxy chips were taken from NUREG/CR-6916 (Reference 95). The testing described in NUREG/CR-6916 was performed using different sizes of paint chip debris for a variety of coatings systems typically used in nuclear power plants. Since the size distribution and the exact coating system of the unqualified epoxy chips at CNP was not known, the most conservative epoxy chip settling and bulk tumbling velocity metrics were selected from NUREG/CR-6916.

The most conservative settling velocity reported in NUREG/CR-6916 (0.13 ft/s) was for the two coat epoxy system with a chip size of 1/64 in to 1/32 in. For larger two coat epoxy chips and the other epoxy chips tested, the settling velocities were as high as 0.46 ft/s.The most conservative bulk tumbling velocity reported in NUREG/CR-6916 (0.27 ft/s)was also for the two coat epoxy system, but for curled 1 in to 2 in chips rather than the 1/64 in to 1/32 in chips. The smaller 1/64 in to 1/32 in two coat epoxy chips had a much higher bulk tumbling velocity of 1.01 ft/s reported in NUREG/CR-6916.

The 0.27 ft/s tumbling velocity is also bounding for the majority of incipient tumbling velocities measured, although a few of the chip types/sizes tested had lower incipient tumbling velocities.

The incipient and bulk tumbling velocities for this testing were defined as the velocity at which the first chip begins to move, and the velocity at which 80% of the chips move. The bulk tumbling velocity was judged to be the most appropriate transport metric for this analysis, since it is most representative of the paint chip debris. Also, the incipient tumbling velocity for a distribution of various sizes of the same two coat epoxy chips was measured to be 0.32 ft/s, which is bounded by the bulk tumbling velocity used for this analysis.Given the low turbulence required to keep fine material suspended, if the turbulence is low enough for fines to settle, it is virtually guaranteed that the water velocity will not be high enough to slide the fines along the floor. Therefore, the tumbling or sliding of fine sunken (settled) material (e.g., individual fibers, coatings particulate, dirt and dust) along the floor was not considered.

Figure 3e1-10 in the response to Information Items 3.e.1 and 3.e.3 shows the debris distribution for fine debris and unqualified coatings.

Table 3h2-1, below, provides the overall transport fractions for coatings as provided in the debris transport analysis.

As indicated by the values in bold script, all coatings except for non-OEM epoxy chips have a resulting transport fraction that exceeds 100% of the debris available for transport.

This provides significant conservatism in the assumed coatings debris load at the strainers.

Attachment 3 to AEP:NRC:8054-02 Page 242 Table 3h2-1 Combined Coatings Transport Fraction to Main and Remote Strainers for Loon 4 Breaks Debris Type Size Transport Fraction Qualified Epoxy Fines (1) 96%Unqualified Epoxy (Inside ZOI) Fines (1) 96%Unqualified Alkyd (Inside ZOI) Fines (1) 96%Unqualified OEM Epoxy (Outside ZOI) Fines 112%Unqualified OEM Alkyd (Outside ZOI) Fines 104%Unqualified Non-OEM Epoxy (Outside Chips ZOI) (htsde52%Unqualified Non-OEM Alkyd (Outside Fines 117%ZOI)Unqualified Cold Galvanizing Fines 128%Compound (Outside ZOI)(1) 8% of these fines are assumed to be transported to the reactor cavity (an inactive volume) during blowdown transport and are unavailable for pool fill or recirculation transport.

Therefore, even though this table shows less than 100% are assumed to be transported to the strainers, the transport fraction still shows greater than the available quantity (92%) are assumed to be transported.

I&M Response to Information Items 3.h.3 and 3.h.4 Strainer head loss testing was performed with the use of surrogate material (stone flour) for all coatings debris except for unqualified non-OEM epoxy and non-OEM alkyd. The basis for acceptability for use of stone flour as the surrogate is provided below.The coatings particulates are assumed to have a sphere diameter of 10 microns, consistent with SER Section 3.4.2.1. The strainer vendor, CCI, used stone flour as the surrogate material since it has an S, value similar to that of a 10 micron sphere. The Sv for a 10 micron sphere is 0.6 m 2/cm 3.The Sv for stone flour is 0.776 m 2/cm 3.The stone flour has a size of approximately 7.7 microns. The density of the stone flour was determined to be 167.4 lbs/ft 3.The densities for the coatings are indicated on Table 3h5-1, Table 3h5-2, and Table 3h5-4.Testing was performed using a volume of stone flour equal to the volume of coating material.To establish this volume, the total mass of the coatings particulate was divided by its density.The resulting volume was then multiplied by the density of the stone flour to obtain the mass of stone flour to be used for testing. This was done for each of the coatings particulates listed in Table 3h5-1, Table 3h5-2, and Table 3h5-4.The non-OEM epoxy and alkyd coatings were represented by coatings chips for testing as follows: ' 10% by weight -250 to 500 microns diameter 80% by weight -500 to 1000 microns diameter 10% by weight -1000 to 4000 microns diameter Attachment 3 to AEP:NRC:8054-02 Page 243 The coatings materials were sieved to achieve the correct size distribution.

The coatings thickness was approximately 4 mils DFT prior to processing into chips.As discussed in the response to Information Item 3.d.3, CNP does not have any purely fibrous debris except for that quantity assumed as latent fiber. The area of the strainers provides substantial margin against the formation of a fiber only thin bed. CNP does have sufficient quantities of Cal-Sil to effectively form a Cal-Sil thin bed on the strainers.

Since the SER does not address a Cal-Sil thin bed and does not address which type of coatings debris to use for testing with this type of a bed, engineering judgment was used to specify the size distribution.

The majority of the equivalent coatings debris used for testing was in the form of fine particulate (stone flour). A small fraction was used in the form of actual paint chips with the sizes as described above. Since the majority of the paint chips used were smaller than the openings of the strainer, the intent of using small particulate was met for the strainer testing that was performed.

I&M Response to Information Items 3.h.5 and 3.h.6 The debris generation analysis made the following assumptions with respect to qualified and unqualified coatings in containment.

The ZOI radius assumed for safety related coatings is 10D based on SER Section 3.4.2.1. Based on results of qualified coatings testing documented in WCAP-16568-P,"Jet Impingement Testing to Determine the Zone of Influence (ZOI) for DBA-Qualified/Acceptable Coatings" (Reference 87), the.ZOI for epoxy coatings could be reduced to 4D. The analysis conservatively used 5D and provided data for both the 10D and 5D ZOIs. A CAD model was used to calculate the surface areas of the walls, floors, and steel surfaces in the sphere. All coatings within the ZOI were postulated to fail. Outside of the ZOI, unqualified coatings were postulated to fail; qualified coatings were assumed to remain intact.* All OEM unqualified coatings, except IOZ, outside of the coatings ZOI were assumed to fail initially as paint chips with a thickness equivalent to the original coating thickness.

The EPRI report for OEM coating failures documented autoclave DBA tests of non-irradiated and irradiated unqualified OEM coatings (Reference 92). The EPRI report documented testing on various types of unqualified coatings, alkyds, epoxies and IOZ.A 100% failure of all OEM unqualified coatings is conservative, since Reference 92 has indicated that only about 20% of unqualified OEM coatings actually detached as a result of autoclave DBA testing. Detachment is considered failure of a coating system. Any non-detached coatings are not considered failed. This illustrates that assuming 100%failure of OEM unqualified coatings is conservative.

The coatings detach initially as chips that have a thickness equivalent to the original coating thickness which is consistent with Reference

92. The EPRI report concluded from the autoclave tests that the failed coating average particle size was 83 microns for some samples and 301 microns for other samples. These particles were retrieved from the DBA test autoclave from recirculating loop filters, and hence the coating debris was constantly being recirculated throughout the autoclave test. Therefore, an average particle size of 83 Attachment 3 to AEP:NRC:8054-02 Page 244 microns was conservatively used in this calculation for unqualified OEM epoxy and alkyd coatings outside the ZOI. Additionally, the report "Failed Coating Debris Characterization" (Reference

96) documents use of autoclave test data gathered by the BWROG Containment Coating Committee to simulate LOCA exposure and gain insight into post-LOCA failure mechanisms.

The results showed that all but the IOZ paint failed in macro-sized pieces.The non-OEM -unqualified coatings outside the ZOI have the same failure rate as the OEM coatings outside the ZOI (100%). Since the non-OEM unqualified coatings are not applied to a correctly prepared substrate, it is expected that these coatings would fail as chips of various sizes. Therefore, the non-OEM unqualified epoxy and alkyd coatings outside the ZOI were assumed to fail with chip sizes of 10% (250 -500 microns), 80%(500 -1000 microns), and 10% (1000 -4000 microns).

Autoclave testing (Reference

97) indicates that paint chips would be generated in sizes larger than 4000 microns which shows that the distribution used in this calculation is conservative.

The cold galvanizing coating used at CNP is an organic zinc material.

Absent test data, it was assumed to fail as 10 micron particulate, which is conservative for head loss.I&M conducted extensive walkdowns to obtain input for development of a calculation to quantify the unqualified coatings in containment (Reference 67). This calculation documented the estimated quantity of unqualified coatings, with substantial conservatism, to be used as input for the debris generation analysis.The two types of unqualified coatings are non-OEM epoxy and non-OEM alkyd. The source of non-OEM epoxy coatings consists principally of the single top coat applied to embedded galvanized unistrut and copper grounding cables. The non-OEM epoxy coating was qualified for other applications but not qualified for the galvanized unistrut or copper grounding cable applications.

The source the non-OEM alkyd coatings consists principally of the color coding applied to galvanized cable tray splice plates, galvanized conduits, and stainless steel labels wired to conduits to differentiate the electrical trains and channels.The coatings debris determined by the debris generation analysis, for the bounding breaks as described in the response to Information Item 3.a.3, are provided in Tables 3h5-1 through 3h5-4, below, for the DEGB and DGBS.

Attachment 3 to AEP:NRC:8054-02 Page 245 Table 3h5-1 DEGB Coating Debris Generated Within ZOI Coating Type Area, ft2 Thickness, Analysis Size, Volume, Density, Weight, mils microns ft 3 lbs/ft 3 lbs Qualified Coatings -Concrete Surfaces 894 12 10 0.894 111.6 99.8 (ZOI -5D)Qualified Coatings -Steel Surfaces 1,007 12 10 1.007 111.6 112.7 (ZOI -5D)Total Qualified 1,901 --1.90 -212.5 (ZOI -5D)Unqualified Alkyd Coatings 57.7 4 10 0.019 98 1.9 (ZOI -1OD)Unqualified Epoxy Coatings 112.0 4 -10 0.037 94 3.5 (ZOI -1OD)Total Unqualified 169.7 --0.056 -5.4 (ZOI -IOD)Table 3h5-2 DGBS Coating Debris Generated Within ZOI ft= Thickness, Analysi's Size, Volume, Density, Weight, Coating Type Area, mils microns ft 3 Ibs/ft 3 lbs Qualified Coatings-Concrete 0 12 10 0.0 111.6 0.0 Surfaces (ZOI -5D)Qualified Coatings-Steel Surfaces 20 12 10 0.02 111.6 2.2 (ZOI -5D)Total Qualified 20 --0.02 -2.2 (ZOI -5D)Unqualified Alkyd Coatings 16.9 4 10 0.006 98 0.6 (ZOI -10D)Unqualified Epoxy Coatings 56.0 4 10 0.019 94 1.8 (ZOI -1OD)Total Unqualified 72.9 0.025 -2.4 (ZOI -10D) _ 9_

Attachment 3 to AEP:NRC:8054-02 Page 246 Table 3h5-3 Unqualified Coatings Location Unit I and Unit 2 Bounding Values Debris Type Upper Loop Pipe Ice Total Containment Compartment Annulus Condenser Total Unqualified OEM EoyCatins lbs 3.96 3.29 10.61 0 17.86 Epoxy Coatings, Ibs.Unqualified OEM aldCins lbs 5.89 4.30 64.97 0.30 75.46 Alkyd Coatingls, Ibs Unqualified Non-OEM Epoxy 7.86 9.28 15.76 0 32.9 Coatings, lbs Unqualified Non-OEM Alkyd 0.78 1.46 1.58 0 3.82 Coatings, lbs Unqualified Cold Galvanizing 34.21 56.76 56.76 629.77 777.5 Compound, lbs Table 3h5-4 Unqualified Coatings Debris Generated Outside ZOI ft2 Thickness, Analysis Size, Volume, Density, Weight, Coating Type Area, mils microns ft 3 Ibs/ft 3 lbs Unqualified OEM Alkyd Handwheels, and Limitorque 1,429.5 4 83 0.48 98 47.0 Coatings outside 1OD ZOI Remaining Unqualified OEM 841.7 4 83 0.28 98 27.4 Alkyd Coatings outside 10D ZOI Remaining Unqualified OEM 538.0 4 83 0.18 94 16.9 Epoxy Coatings outside 10D ZOI Unqualified non- 10% (250-500)OEM Alkyd 105.8 4 80% (500-1000) 0.035 98 3.4 Coatings outside 10%(1000-4000) 1OD ZOI Unqualified non- 10% (250-500)OEM Epoxy 991.2 4 80% (500-1000) 0.33 94 31.0 Coatings outside 10% (1000-4000) 1OD ZOI Cold Galvanizing 9,324.98 4 10 3.11 250 777.5 Compound I_3,31.1 -I4.415 -_903.2 Total 13211Unqualified 13211- 4.415 -903.2 Attachment 3 to AEP:NRC:8054-02

'Page 247 I&M Response to Information Item 3.h.7 As provided in I&M's response to GL 98-04 (Reference 108), I&M has implemented a Safety Related Coatings Program. This coatings program has been further enhanced to provide additional evaluation of coatings failures.

This program is governed by EHI-5065, Safety-Related Coatings Program (Reference 98). The safety related coatings program includes the following elements." Selection/Qualification of Coating Systems The requirements for qualification and selection of safety-related coatings are delineated in specification ES-CIVIL-0408-QCN, Requirements for Material Selection, Surface Preparation, Application and Inspection (Reference 99).* Material Procurement and Management The requirements for the material procurement and management of safety-related coatings are delineated in specification ES-CIVIL-0400-QCN, Procurement, Receipt Inspection, Storage and Documentation of Protective Coatings (Reference 100).* Surface Preparation, Coating Application and Inspection The requirements for surface preparation, application and inspection of safety-related coatings are delineated in Reference 99, and are implemented by the following procedures:

12-CHP-5021-CCD-011, Application of Protective Coating to Steel Surfaces in Areas Classified as Coating Service Level I and for Coating Service Level III Lining Applications (Reference 101)." 12-CHP-5021-CCD-012, Application of Protective Coating to Concrete Floor, Wall, Ceiling and Block Wall Surfaces in Areas Classified as Coating Service Level I (Reference 102).* Condition Assessment The requirements for the assessment of the safety-related coatings are delineated in procedure 12-EHP-5065-SRC-001, Condition Assessment of Safety-Related Coatings (Reference 103)." Management and Evaluation of Non-Conforming Coatings The evaluation of safety-related coating assessments and non-conforming coatings are delineated in procedure 12-EHP-5065-SRC-002, Management and Evaluation of Non-Conforming Coatings (Reference 104).

Attachment 3 to AEP:NRC:8054-02 Page 248* Qualification/Certification of Coating Applicators and Inspectors The qualification/certification requirements for safety-related coating applicators are delineated in specification DCC-CEST-145-QCN, Painter Training, Qualification and Certification (Reference 105).The qualification/certification of safety-related coating inspectors are delineated in procedure PDP-7040-001, Qualification and Certification of Inspection, Test, Examination and NDE Personnel (Reference 106).I&M performs an assessment of containment coatings each refueling outage per the requirements of Reference 103. The personnel performing this assessment are coatings certified Performance Verification (Quality Control) inspectors.

This inspection is a visual inspection which is validated by EPRI Report No. 1014883, "Plant Support Engineering:

Adhesion Testing of Nuclear Coating Service Level I Coatings," August 2007 (Reference 107).Reference 103 requires that a report be developed to document the results of the inspection as well as requiring entering each area of degraded or non-conforming coatings.

into CNP's Corrective Action Program. The Safety-Related Coatings Program owner is required to evaluate the results of the coatings inspection per the requirements of Reference 104. This evaluation includes determination of the probable cause of the coatings failure, the extent of condition, and any additional inspection or testing that may be required to fully bound the condition.

I&M performs remediation of identified degraded or non-conforming safety-related coatings inside containment prior to ascension to Mode 4 during the outage in which the coating failure is identified, or performs a non-conformance evaluation to demonstrate that the quantity of deficient coatings will not impact the inputs and assumptions associated with the recirculation function.

Attachment 3 to AEP:NRC:8054-02 Page .249 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.

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), pro vide 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 Attachment 3 to AEP:NRC:8054-02 Page 250 I&M Response to Information Item 3.i.1 I&M has procedures and processes to assure containment cleanliness is maintained at a level that will ensure the latent debris burden inside containment remains at or below the total quantity assumed in the recirculation sump strainer analyses.

The necessary housekeeping requirements are a part of the work package and pre-job brief for each work activity inside containment.

I&M has a housekeeping procedure (Reference 121.) in place that requires: " All personnel maintain a "clean-as-you-go" approach to all work activities throughout the plant." I&M and contractor personnel to be trained in housekeeping and material condition program requirements." Restoring work areas to conditions which are equal to or better than the pre-start condition." That, upon completion of a work activity (including clean-up), the work group supervisor ensures the work area is returned to a better state of cleanliness than when the activity started.During outage periods, periodic assessments of the status of containment cleanliness conditions are performed -and reported to station management.

Prior to the end of the scheduled outage, an extensive containment cleaning effort is undertaken including vacuuming of accessible surfaces.

Following cleaning in an area of containment, multiple walkdowns are performed by members of station management, members of the Performance Assurance organization, and by Operations personnel as part of their containment close-out inspection.

The Operations Department procedures for containment inspections (References 122 and 123)contain requirements for Operations personnel to look for accumulation of tightly adhered films of dirt and grime on surfaces, or unencapsulated insulation.

Upon identification of these items, the procedure requires that the conditions be entered into the corrective action process.Commencing with the Unit 2 Spring 2009 RFO, and for every Unit 1 and Unit 2 RFO thereafter, the Containment Recirculation Sump Protection Program Owner will (in accordance with Reference 124) be directing the performance of an assessment of containment debris sources to ensure the associated analytical assumptions and numerical inputs that provide assurance of compliance with 10 CFR 50.46 and related regulatory requirements have been maintained.

I&M will perform sampling of latent debris in containment when major work activities that could result in the generation of significant quantities of latent debris are performed, e.g., SG replacement.

I&M has implemented programmatic and process controls as described throughout the response to this information item, and has determined the quantity of latent debris in containment with substantial conservatism as described in the response to Information Item 3.d.3.

Attachment 3 to AEP:NRC:8054-02 Page 251 I&M Response to Information Item 3.i.2 I&M has established extensive and comprehensive programmatic and process controls to limit the introduction of debris sources into containment during outage periods and during containment entries. These controls include both engineering requirements for changes to the plant and process controls to ensure materials taken into containment are limited and controlled to ensure the inputs and assumptions that support overall resolution of GL 2004-02 will be maintained.

The FME programmatic controls that have been implemented include:* Establishment of a procedure that defines the attributes of, and responsibilities for, implementation of the Containment Recirculation Sump Protection Program (Reference 125).* Changes to the procedure for FME (Reference 126) that requires that each individual entering containment, during the periods in which containment is required by TS to be operable, to document all items being taken into containment on a Personnel Tool/Material Accountability Log, and to verify that these items were removed upon exit from containment, or satisfactorily dispositioned as having been installed or intentionally left in containment per previously approved and evaluated work order instructions." Changes to the containment access control procedure (Reference 127) that requires an evaluation be performed of major maintenance activities, e.g., work that has the possibility of creating or introducing significant amounts of dirt, dust, or other debris sources. This procedure also requires personnel that enter containment to attest, by signature, that all items taken into containment were removed except as provided by the specific work order activity instructions.

This procedure also requires verification that, when the associated areas are entered, the TS required flow paths (CEQ Fan Room drains and Flood-up Overflow Wall openings) are not obstructed by debris, and that there is no debris in the area that could obstruct them. This procedure applies during those periods when containment is required by TS to be operable.* Changes to the work order task planning procedure (Reference 128) that requires planners to ensure the evaluation required by the containment access control procedure, when necessary, is completed to support the task planning." Changes to the procedures (References 129 and 130) that provide the requirements for procurement of materials, such that any item intended to be installed inside containment is required to meet the engineering specification for materials inside containment (Reference 131).* Changes to the plant labeling procedure (Reference 132) that requires any new labels to be installed on plant equipment inside containment (valves, etc.), be fabricated of etched, engraved, or stamped stainless steel and attached with stainless steel tie wire or tie wraps." Development of an engineerinrg program, with attendant procedures (References 124 and 133), for the containment recirculation sump function which includes the assessment of debris sources described in the response to Information Item 3.i.1, and provides for continuous monitoring of conditions potentially affecting the recirculation function.

Attachment 3 to AEP:NRC:8054-02 Page 252* Changes to the engineering specification that establishes the requirements for material inside containment (Reference 131).I&M will maintain the necessary programmatic and process controls, such as those described above, to ensure the ECCS and CTS recirculation functions are maintained in accordance with the applicable regulatory requirements identified in GL 2004-02.I&M is continuing to evaluate station programs and processes to ensure the necessary controls to prevent the introduction of foreign material into containment will be in place prior to implementation of the new mechanistic design and licensing basis requirements that support resolution of GL 2004-02, as approved by Reference

16. Implementation of any additional necessary changes will be established in accordance with the schedule provided in the response to Information Item 2.I&M Response to Information Item 3.i.3 I&M has revised the applicable Engineering Change Reference Guide (Reference 134) to ensure any changes to SSCs inside containment or that-are part of the recirculation flow path are fully evaluated to ensure the changes will not adversely impact the inputs and assumptions associated with the analyses that support resolution of GL 2004-02. This procedure is invoked by engineering change procedures and other change review procedures.

Engineering change processes are supported by engineering specifications and standards.

Those specifications and standards that were considered to be important for preventing the introduction of debris sources or other materials that could impact the recirculation function were changed to prevent potentially adverse impacts.Upon implementation of the new design and licensing basis associated with the mechanistic evaluation of the recirculation function, the UFSAR will contain sufficient information to ensure changes to the facility are evaluated in accordance with 10 CFR 50.59 requirements.

I&M Response to Information Item 3.i.4 An assessment of risk associated with maintenance activities is required for HSSSs in accordance with 10 CFR 50.65(a)(4).

This 10 CFR 50.65 paragraph requires that, before performing maintenance activities (including but not limited to surveillance, post-maintenance testing, and corrective and preventive maintenance), the licensee shall assess and manage the increase in risk that may result from the proposed maintenance activities.

The scope of the assessment may be limited to SSCs that a risk-informed evaluation process has shown to be significant to public health and safety. The containment recirculation sump function of accumulating and directing water to support the ECCS and CTS functions is classified as a HSSS per the associated CNP Maintenance Rule Scoping Document (Reference 140).The CNP On-Line Risk Management procedure (Reference 135) provides guidance for performing a risk impact resulting from maintenance activities with a unit in Mode 1, 2, or 3.Risk levels are determined via a risk assessment using appropriate quantitative (PRA/IPE methods and models) and qualitative (judgment) means. The proposed work schedule risk assessment is performed independently by at least two qualified individuals (at least one of ,whom is an Operations individual) prior to the work week in which the activity is scheduled.

Attachment 3 to AEP:NRC:8054-02 Page 253 Schedule changes are reviewed for potential impact on risk by at least two qualified individuals and, if a PRA related SCC function is affected, then the risk assessment is revised to account for the proposed change. The risk assessment considers a variety of factors including:

TS requirements.

The degree of redundancy available for performance of the safety functions(s) served by the out-of-service SSC.* The duration of the out-of-service or testing condition.

The likelihood that the maintenance activity will significantly increase the frequency of a risk-significant initiating event.* Component and system dependencies that are affected, including consideration of work in progress on one unit that may impact the availability of SSCs on the other unit." Significant performance issues for the in-service redundant SSCs. /* The impact of temporary plant modifications and temporary procedure changes on the risk level of the plant.* The impact of external conditions, such as weather, switchyard work, and grid reliability, including limitations that may be imposed on activities in the event that severe weather or degraded grid conditions may -prevail.The risk assessment also considers the impact on alterations associated with the maintenance activity on plant safety functions.

A determination is made of the appropriate actions to control risk for a maintenance activity, which is specific to the particular activity.

This determination considers the impact on risk and the practical means available to control the risk.Compensatory measures may also be employed, either prior to or during maintenance activities, to mitigate risk impacts.The Plant Shutdown Safety and Risk Management procedure (Reference 136) provides guidance for maintaining an adequate level of shutdown safety during outages (Modes 4, 5, 6, and defueled).

Outage schedules are developed with due consideration of defense in depth.Specifically, focus is placed on:* Maximizing the number of flow paths to inject water to RCS.* Maximizing reliability of equipment important to shutdown safety.* Minimizing time spent in reduced inventory or mid-loop condition.

Potential PRA impact on the other unit.Prior to starting a planned outage, the overall proposed outage schedule is reviewed by a RAT and a representative from the PRA Group. The schedule review considers all facets of shutdown safety. To ensure that all aspects of shutdown safety are considered, the shutdown risk assessment is performed in eight discrete functional areas (referred to as key safety functions) which include shutdown cooling and inventory control, as examples.The schedule evaluation is performed using the CNP shutdown risk model in the ORAM program, which is a computerized model for shutdown risk monitoring, or equivalent logic sequence.

Time blocks in the schedule are assessed for level of defense associated with a key safety function.

If a reduced level of defense is noted, contingency plans may be developed to maintain an adequate level of defense.

Attachment 3 to AEP:NRC:8054-02 Page 254 I&M Response to Information Item 3.i.5 I&M removed the Cal-Sil insulation from the PRT and PZR safety and relief valve discharge line below the PZR floor in both Units 1 and 2 (approximately 210 ft 3 in each unit). In Unit 1, LDFG insulation on the combined non-RCS systems relief valve discharge line to the PRT was removed (approximately 4 ft 3). In Unit 2, the Cal-Sil insulation on the PRT drain line was removed (approximately 10 ft 3). These last two insulation sources did not exist in the opposite unit. These insulation removal efforts occurred during the Unit 1 Fall 2006 RFO and the Unit 2 Fall 2007 RFO.I&M Response to Information Item 3.i.6 As provided in the 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 single jacketed insulation with bands spaced at approximately 12 in intervals.

The insulation on applicable service water lines in Unit 2 has been double jacketed with stainless steel jacketing with banding applied at intervals not to exceed 6 in. A design standard (Reference 137) was developed detailing the installation requirements.

The engineering specification for insulation requirements (Reference 138) and the maintenance procedure for installation of insulation (Reference 139) were also revised to require the configuration of the foam insulation installed on the service water lines in the affected area meet the requirements of the engineering standard (Reference 137).I&M Response to Information Item 3.i.7 As described in the response to Information Items 3.b.5, 3.i.5, and 3.i.6, I&M removed a significant quantity of labels from containment.

I&M also removed areas of leveling compound from the floor in the loop compartment in Unit 2 containment during the Fall 2007 RFO that would have contributed a significant quantity of unqualified coatings to the overall debris source term. This material was previously removed in Unit 1.I&M Response to Information Item 3.i.8 A description of the actions that I&M has taken to modify or improve the containment coatings program was provided in the response to Information Item 3.h.7.

Attachment 3 to AEP:NRC:8054-02 Page 255 NRC Information Item 3.m -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 I&M has performed extensive plant modifications to support resolution of the GL 2004-02 concerns.

I&M has completed these changes in Unit 2. I&M has completed these changes in Unit 1, except for the remote strainer, flood-up overflow wall debris interceptor, annulus debris gate, and flood-up overflow flow wall openings and radiation shield. In accordance with Reference 16, I&M will complete installation of the Unit 1 plant modifications during the Spring 2008 RFO. The plant modifications are described below.Recirculation Sump Strainers The CNP ice condenser containment is significantly smaller than the containments for non-ice condenser plants. Consequently, the size of the original recirculation trash racks and screens could not be significantly increased.

I&M elected to replace the existing trash racks and screens with CCI pocket-style strainers that integrate the trash rack and screen functions while significantly increasing the overall surface area. I&M also elected to provide additional capacity by installing a remote strainer in the annulus outside the RCS loop compartment.

This remote strainer is connected to the recirculation sump via a sealed waterway that penetrates the divider wall in the recirculation sump. This divider wall is an extension of the containment crane wall.Refer to Attachment 4, Figure A4-1, for a drawing illustrating this installation.

The total recirculation sump strainer area was increased from 85 ft 2 to 1972 ft 2.The main strainer has an effective strainer area of 900 ft 2 and the remote strainer has an effective area of 1072 ft 2.The screen/strainer openings were reduced from nominal 1/4 in square openings to nominal 2.1mm (- 1/12 in.), maximum 2.4mm (- 3/32 in.), circular openings.

The strainers are constructed primarily of stainless steel. The minimum submergence of the strainers at the minimum water level for a LBLOCA is greater than 6 in. Refer to Figures 3j1-1 through 3j1-4 for illustrations and photographs of the new recirculation sump strainers.

The Unit 1 and Unit 2 main and remote strainers are essentially mirror images of each other.The new main strainer replaced the previously installed grating and screen. The new main strainer was anchored to the existing embedded anchor bolts. The 7 in high concrete curb at the base of the old grating and screen was removed and a nominal 4 in support base for the new strainer was installed.

A total of 28 cartridge assemblies, each containing 24 pockets (arranged in 2 columns of 12 rows) were installed.

Separating the cartridge assemblies at specified intervals are portions of the strainer module frame (stiffener plates) to provide rigidity to the structure.

The strainer cartridges are attached to the bottom support base with lock bars and fasteners.

The tops of the strainer cartridges are held in place with the upper support brackets to which the stiffener platesare also bolted. End sealer panels are installed at the Attachment 3 to AEP:NRC:8054-02 Page 256 ends of the strainer cartridges.

The end sealer panels are bolted to the recirculation sump side walls and the end.cartridge stiffener plates.Figure 3j1-1 Unit _ Main Strainer Illustration 2 3 4 5.... I DC COOK MAIN STRAINER MODULE ARRANGEMENT UNIT ONE (1)(2)(3)(4)(5)Upper Frame Supports Base Frame Supports Strainer Module Frame (stiffener plates)End Sealer Panels Strainer Modules (cartridges)

Attachment 3 to AEP:NRC:8054-02 Page 257 The remote strainer (installed in the annulus) consists of three interconnected self-supporting sections.

Two of the sections are full length sections and one section was shortened to allow the overall strainer assembly to fit into the desired location.

There is a slight angular offset between each of the sections to provide access between the strainer assembly and refueling cavity wall. A total of 40 strainer cartridges, each containing 20 pockets (arranged in 2 columns of 10 rows) were installed.

The flow channels in the center of each section vary in width. The section farthest from the outlet has the narrowest channel, the center section has a wider channel, and the section connected to the waterway has the widest channel. This was done to reduce the head loss in the flow channel. The strainer sections are anchored to the annulus floor.

Attachment 3 to AEP:NRC:8054-02 Page 258 Figure 3j1-3 Unit 2 Remote Strainer Illustrations (Note: Illustrations do not show all cartridges installed) 001 Attachment 3 to AEP:NRC:8054-02 Page 259 rg 2UI.-A I nit I RamnfaA trminar Recirculation Sump Vents I&M modified the recirculation sump vents to ensure the design vent functions would not be inhibited by accident generated debris, and ensure that debris larger than the recirculation sump strainer openings would not bypass the strainers.

The previous configuration had nominal 1/4 in openings in both the front compartment section vent pipe covers (directly behind the main recirculation sump strainer) and in the rear compartment vent pipe that extends above the maximum containment flood elevation.

The 3/4 in vent holes in the front section cover were enclosed with collector boxes that were piped to the 6 in vent pipe from the rear section of the sump. The top of the 6 in vent pipe was reconfigured such that the vent surface was changed from a horizontal configuration to a vertical configuration with a solid top flat plate. This change also increased the available vent area for the 6 in vent pipe.Recirculation Sump Level Instruments New level instruments were added inside the recirculation sump enclosures to provide indication and alarm in the control room. During the recirculation phase of ECCS operation, these instruments would alert the operators to a condition in which head loss across the strainers had caused the water level inside the sump to decrease to the analyzed vortex limit. The operators could then take action to reduce flow and restore sump level in accordance with in the CNP Attachment 3 to AEP:NRC:8054-02 Page 260 Emergency Operating Procedures.

The level instruments are environmentally qualified float switches that are installed behind stilling well covers. The level instruments are located on the section of the crane wall inside the recirculation sump enclosure.

The level instruments meet RG 1.97 requirements for post-accident monitoring as described in References 11, 12, and 14.Debris Interceptors I&M installed debris interceptors over the drains from the CEQ fan rooms to ensure drainage of CTS water from the upper compartment of containment to the lower containment sump pool.Debris interceptors were installed on the loop compartment side of the flood-up overflow wall to reduce the potential for the flow holes in the flood-up overflow wall to become blocked during pool fill and recirculation.

Debris interceptors were also installed around the openings of the Containment Wide Range Level instruments stilling wells to reduce the potential for debris to completely block their inlet openings.

A debris gate was installed in the annulus area outside the crane wall to provide defense in depth against the transport of debris inadvertently left in containment to the remote strainer.

Refer to Figure 3jl-5 for a picture of the flood-up overflow wall debris interceptor (one section).ira Ail A unit 2 Finnti-I in flvgrflnwwnii flahria Intrr~i Flood-Up Overflow Wall Openinqs and Radiation Shield I&M modified the openings on the five existing 10 in diameter openings that exist in the flood-up overflow wall by flaring the edges of the holes to reduce head loss across the openings.Additionally, the radiation shields that are installed on the annulus side of the openings were modified by removing approximately 2 in from the bottom of the shields to prevent debris from building up between the shields and the flow openings, potentially impacting flow through these openings.

The same modifications will be completed in Unit 1 in the Spring 2008 RFO as allowed by Reference

13.

Attachment 3 to AEP:NRC:8054-02 Page 261 Lower Containment Sump to Recirculation Sump Crossover Pipe I&M installed a blank plate in the crossover pipe that connects the lower containment sump to the recirculation sump. These sumps are adjacent to each other inside the crane wall.Previously, the connecting pipe had a nominal 3/16 in mesh screen installed to limit the size of debris that could be transported from the lower containment sump to the recirculation sump.Installation of the blank plate will prevent any debris from bypassing the recirculation sump strainers through the crossover pipe.CEQ Fan Room Drain Paths In Unit 2, I&M installed a vent on the lower containment sump, and removed the internals from the check valves in the west CEQ fan room drain lines to ensure any CTS water entering the CEQ fan rooms could flow to the containment sump pool. The check valve internals had previously been removed from the Unit 2 east CEQ fan room drain line. In Unit 1, the CEQ fan room drains are routed to the pipe tunnel sump, outside the crane wall, which has an existing flow opening. The check valve internals in the Unit 1 CEQ fan room drains had previouslybeen removed.I&M Response to Information Item 3.0.2 In Unit 2, I&M 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.* Re-orientation of pipe tunnel sump level switches.* Removal of valves, piping, and a support for the Containment Penetration and Weld Channel Pressurization system, and installation of pipe caps on the lines.* Relocation of a Reactor Coolant Drain Tank relief valve line.* Partial removal of a pipe whip restraint.

Relocation of an accumulator drain line.* Removal of stud bolts on containment pipe tunnel sump cover.* Removal of a type ABC fire extinguisher adjacent to the Pipe Tunnel sump.* Removal and capping of a segment of the previously disconnected stem packing leak off line.* Shortening of a demineralized water line.* Replacement of a support for RCS Loop 2 flow instrument manifold valves with a new design.In Unit 1, I&M will be performing 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.

Attachment 3 to AEP:NRC:8054-02 Page 262* 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.

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.V

-Attachment 3 to AEP:NRC:8054-02 Page 263 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 Reque~ted 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 As stated in the response to Information Item 3.j.1, a new main strainer has been installed in Unit 1 and Unit 2, a remote strainer has been installed in Unit 2, and a remote strainer will be-installed in Unit 1 during the Spring 2008 RFO.The new main strainer is anchored to the existing embedded anchor bolts in the floor, walls, and cover for the recirculation sump enclosure.

The remote strainer is anchored to the floor of the annulus with undercut style anchor bolts.The design inputs for the strainer qualification consisted of the containment seismic response spectra, maximum flood elevation, temperatures based on event time, flow rates for pool fill and recirculation, waterway loads acting on the remote strainer connections, debris loads on the strainers, and differential pressure from the short term mass and energy release. The governing code for qualification of the strainer is the CNP code of record, AISC, 7 th Edition. The input used for the qualification of the strainers is provided below.The following load cases were used for the design and qualification of the main strainer for Unit 1 and Unit 2, and the remote strainer for Unit 2. The same load cases are being applied to the Unit 1 remote strainer which will be installed in the Unit 1 Spring 2008 RFO. Load cases 1 through 4 were used for design and qualification of the waterway for Unit 2, and will be used for the design and qualification of the waterway for Unit 1.

Attachment 3 to AEP:NRC:8054-02 Page 264 Load Case 0 (Original Case: Full Recirculation Flow with Clean Main Strainer Applicable to Main Strainer and Remote Strainer)DW + TAL + DBE + FRHL + DL + NL(t)Load Case Oa (Original Case: Full Hydrostatic Load with Assumed Blocked Strainer Applicable to Main Strainer and Remote Strainer)DW + TAL + HTL + DBE + DL + HD Load Case 1 (Immediately after Break: Applicable to Main Strainer and Remote Strainer)DW + TBL + DBE + NL(t)Load Case 2 (Containment Fill: Forward Flow Through Main Strainer with Reverse Flow Through Waterway to the Remote Strainer)DW + TFL + DBE + NL(t) + PFHL Load Case 3 (Dirty Main Strainer with Recirculation Flow from Remote Strainer)DW + TAL + DBE + FRHL + DL + NL(t)Load Case 4 (Pressure Pulse at Instant of Break; Applicable to Main Strainer and Remote Strainer)DW + TOL + PP + NL(t)Load Definitions:

DBE Design Basis Earthquake.

DL Debris Load of 1986 lbs for the main strainer and 1530 lbs for the remote strainer.DW Dead Weight.FRHL Full ECCS recirculation hydraulic loads (14,400 gpm).HD Hydrodynamic load from seismic induced slosh of pool.HTL Hydrostatic Load of 15.1 ft of water (maximum containment flood elevation) treated as maximum head loss for analysis purposes.NL(t) Nozzle Loads, applicable only to the remote strainer and local conditions at the time of the load case.PFHL Pool Fill Hydraulic Loads -reverse flow and waterway loads.PP Short term pressure (pressure pulse) of 5.0 psid for the main strainer, and 2.5 psid for the remote strainer.TAL Thermal effects at accident temperature of 160'F.TBL Thermal effects at post-break containment environment temperature of 236 0 F.TFL Thermal Loads During Pool Fill (200 0 F).TOL Thermal effects at normal (maximum) operating temperature of 160°F for the main strainer and 120'F for the remote strainer.

Attachment 3 to AEP:NRC:8054-02 Page 265 For CNP, the vertical seismic acceleration is assumed to be 2/3 of the horizontal seismic acceleration as provided in UFSAR Section 2.5.2. A damping of 2% is applied to the strainers and their elements for the DBE. From the AISC code of record, allowable stresses can be increased 1/3 above the normal allowable values for those conditions that consider seismic loads. The normal allowable stresses from the AISC are provided below in terms of the yield stress, FY.0 0.60 Fy (sometimes designated as Sy) for tension (membrane stress), except at pin holes.* 0.45 Fy for tension at pin holes.* 0.40 Fy for shear.* 0.66 Fy for tension and compression in bending on extreme fibers of compact sections having an axis of symmetry in the plane of bending (membrane plus bending stress).* 0.60 Fy for tension and compression in bending on extreme fibers of unsymmetrical members, box-type members, rolled shapes, built-up members, and plate girders.* 0.60 Fy for tension on bolts and threaded parts.* 0.30 Fy for shear on bolts and threaded parts.* 1.35 Fy for bearing stress on projected area of bolts in bearing-type connections.

The PFHL was established by a CFD analysis of the recirculation sump including the strainers and waterway (Reference 27), and through a finite element analysis of the waterway considering hydraulic loads (from the CFD), temperature stresses on the waterway, and seismic stresses in both the waterway and remote strainer.

The CFD determined the maximum reverse flow rate through the waterway and remote strainer would be 6,400 gpm.I&M Response to Information Item 3.k.2 The primary recirculation sump components for CNP consist of the strainer cartridge assemblies, the main strainer assembly, the remote strainer assembly, and the waterway connecting the remote strainer to the recirculation sump. The results of the structural qualification, and design margins, for each of these components are presented below.The analyses were performed with finite element analysis (using ANSYS and SAPmethodologies) and static calculations.

The main strainers and the strainer cartridges for Unit 1 and Unit 2 main and remote strainers, and the remote strainer for Unit 2 were analyzed by the strainer vendor, CCI, per References 70, 71, and 72. The waterway for Unit 2 was analyzed by S&L, per Reference 59.Strainer Cartridge Assemblies As described in the response to Information Item 3.j.1, the main strainer uses a 24 pocket cartridge and the remote strainer uses a 20 pocket cartridge.

These cartridges were analyzed separately.

Table 3k2-1, below, provides the results of the analysis for the main and remote strainer cartridges and pockets.

Attachment 3 to AEP:NRC:8054-02 Page 266 Table 3k2-1 Main and Remote Strainers Cartridges Structural Analysis Results Element Analyzed Load Case Allowable Stress at 160°F, MPa(4)Allowable Stress at 236°F, MDn(4)Calculated Stress, MPa IR (1)Main Strainer 111 (M)Pocket Non- DW+DL+Perforated HTL (2)Section 122 (M+B)Main Strainer DW+DL+ 46 (M)Pocket Perforated HTL 2 5 Section HTL___51 (M+B)Main Strainer 111 (M)Cartridge Non- DW+DL+Perforated HTL (2)Sheets 122 (M+B)30 0.27 80 0.66 20 0.43 50 0.98 24 0.22 116.9 0.96 14.8 0.32 49.5 0.97 Main Strainer Cartridge Perforated Sheets DW+DL+HTL (2)Remote Strainer DW+TFL+Pocket Non- PFHL at Perforated 2000 F Section Remote Strainer DW+TFL+Pocket Perforated PFHL at Section 2000 F 103 (M) 45 0.44 114 (M+B) 80 0.70 at 200'F 42.9 (M) 12 0.28 47.5 (M+B) 44 0.93 Remote Strainer Cartridge Non-Perforated Sheets 111 (M)99 (M)49 0.44 0.49 DW+DL+HTL (2)122 (M+B)109 (M+B)81 0.66 0.74 0.51 0.63+ F I F Remote Strainer Cartridge Perforated Sheets DW+DL+HTL DW+DL (2)51 (M)122 (M+B)41(M)26 50 [ 0.41 45.4 (M+B) (3)20 0.44 (1) IR = interaction ratio, i.e., the calculated stress divided by the allowable stress.(2) The normal load case using the equivalent load of the hydrostatic head of water was determined to govern over the seismic loading case for an individual pocket due to increased allowable stresses for the seismic case. This case considers the pockets are blocked preventing water movement through them.(3) For this case, the hydrostatic pressure load was not included since it does not occur coincident with the high temperature condition., (4) M = Membrane Stress, B = Bending Stress.

Attachment 3 to AEP:NRC:8054-02 Page 267 Main Strainer Assembly Table 3k2-2, below, provides the results of structural analysis performed for the main strainer support structure.

Table 3k2-2 Main Strainer Support Structure Structural Analysis Results d Allowable Calculated Element Analyzed Aloae Element Case (1) Stress at 236 0 F, Stress, IR (2)MPa(3) MPa Main Strainer DW+TBL+ 89.6 (T) 8.6 0.10 Upper Anchor DBE+HTL+Bolts DL 67.2 (S) 23.4 0.35 Main Strainer DW+TBL+ 99 (T) 4 0.04 Lower Anchor, DBE+HTL+Bolts DL 66 (S) 61 0.92 Main.Strainer DW+TBL+ 109 (B) 52.3 0.48 Upper Retaining DBE+HTL+Angle DL 66.2 (S) 4.2 0.06 Main Strainer Upper Anchor DW+TBL+Bolts from DBE+HTL+ 89.6 (T) 10.8 0.12 Retaining Angle DL Bending Main Strainer DW+TBL+DBE+HTL+ 158 (S) 93 0.59 Cartridge Bolts DL 662()2 0.03 Main Strainer DW+TBL+ 66.2(5)DBE+HTL+ 109 (B) Edge 35 0.32 Sealing Plates D 109 (B) Center 52.4 0.48 Main Strainer DW+TBL+Sealing Plates DBE+HTL+ 67.2 (5) 21.7 0.32 Anchor Bolts DL Main Strainer Sealing Plates DWTL Stainer DBE+HTL+ 158 (S) 41.3 0.26 Strainer Connection Bolts D (1) A bounding load combination was developed trom the applicable load cases.(2) IR = interaction ratio, i.e., the calculated stress divided by the allowable stress.(3) T = Tension Stress, S = Shear Stress, B = Bending Stress.

Attachment 3 to AEP:NRC:8054-02 Page 268 Remote Strainer Assembly Tables 3k2-3 and 3k2-4 below provide the results of structural analyses performed for the remote strainer support structure and waterway connection box.Table 3k2-3 Remote Strainer Support Structure Structural Anal sis Results Allowable Allowable Calculated Element Analyzed Stress at Stress at Stress, IR (2)Case (1) 160OF, 236 0 F, MPa (3) MPa (3) MPa DW+HD+ 0.56 HTL+DL 103.5 (M+B) 85 (M+B) 58 0.6 Standard Support HT+L.0.68 Structure Plates DW+HD+ 0.78 HTL+DL 137.6 (M+B) 124.3 (M+B) 107+/- DBE 0.86 DW+HD+ 353.8 (C) 315.6 (C) 17.5 0.05 Standard Support HTLi-DL 5 0.06 Structure Leveling DW+HD+Screws HTL+DL 353.8 (C) 315.6 (C) 68 0.9+DBE 0.22 Standard Support 280.5 (M) 29.3 0.10 Structure Base All N/A 280.5 (M+B) 119.2 0.42 Support Bolt 140.3(S) 16.1 0.11 Standard Support 280.5 (M) 62 0.22 Structure Unit A All N/A 280.5 (M+B) 190.2 0.68 Base Support Bolt 140.3(S) 23 0.16 DW+HD+ 122.2 (M+B) 113.2 0.93 Blind Cartridges HTL+DL U-Plates DW+HD+ N/A HTL+DL 162.5 (M+B) 137.3 0.84+DBE 0.55 DW+ 94.2 (M) 85 (M) 52 0.61 HTL+DL 0.67 Duct Section 103.5 (M+B) 93.5 (M+B) 69 0.74 Plates 0.74 DW+HD+ 0.84 HTL+DL 137.6 (M+B) 124.3 (M+B) 115+/- DBE 0.93 Cartridge Shear DW+HD+ 176.9 (S) 90 0.51 Pins & Bearing HTL++/-DL N/A Stress in Cartridge

+DBE 221.4 (R) 219.6 0.99 (1)(2)A bounding loaa combination was developed from tne applicable loaa cases.IR = interaction ratio, i.e., the calculated stress divided by the allowable stress.

Attachment 3 to AEP:NRC:8054-02 Page 269 (3) S = Shear Stress, B = Bending Stress, C = Compression Stress, M = Membrane Stress, R =Bearing Stress.Table 3k2-4 Remote Strainer Support Structure and Waterway Connection Box Structural Analysis Results tAnalyzed Allowable Stress Allowable Calculated Case (1) at 160°F, Stress, Stress, IR (2)MPa(3) MPa(3) MPa DW+HD+/- 163.83 (S)Cartridge Shear HTL+DL+ N/A (at 2000 F) 22.5 0.14 Pins & Bearing DBE Stress in Cartridge DW+HD+/- 155.2 (R) 17.5 0.11 (Reverse Flow HTL+DL (at 2000 F)Case 2) DW+HD+/- N/A 206.4 (R)HTL+DL+ (at 2000 F) 54.8 0.27 DBE Cartridge Shear N/A. -157.8(S) 28 0.18 Pins & Bearing DW+TBL+ (at 2360 F)Stress in Cartridge DBE 198 (R)(Case 1) N/A (at 2360 F) 68.4 0.35 Cartridge Shear 190(s) 24.5 0.13 Pins & Bearing DW+TOL+. N/A (at 1200 F)Stress in Cartridge PP 177.9 (R) 59.9 0.34 (Case 4) (at 1200 F).Unit A Support DW+HTL+/-

93.5 (M+B)(connects to outlet DW+HL+/- N/A 93.5 ( ) 80 0.86 UntoxSppr DBE+NL(t) (at 2360 F)box)Bounding 85 (M) 0.56 Loads for 94.2 (M) (at 2360 F) 0.62 Load Cases 0.89 Oa, 2, 3, 4 103.5 (M+B) 93.5 (M+B) 92 First Module with out (at 236 F)0.98 Support (furthest DBE from outlet) Bounding 113 (M) 53 0.42 Loads for 125.1 (M) (at 236' F) 0.47 Load Cases 124.3 (M+B) 0.78 Oa, 2, 3, 4 137.6 (M+B) (at 2360 F) 107 0.86 with DBE Unit A Outlet Bounding 99.2 (M) @160 = 108 0.97 Connection Box Loads for 111.1(M) (at 2360 F) @236 =20.2 0.20 Limiting Plate Load Cases 0.88 Element (side u- Oa, 2, 3, 4 122.2 (M+B) 109.2 (M+B) 108 plate) w/o DBE (at 2360 F) 0.99 (1) A bounding load combination was developed from the applicable load cases.(2) IR = Calculated Stress divided by Allowable Stress Attachment 3 to AEP:NRC:8054-02 Page 270 (3) S = Shear Stress, B = Bending Stress, M = Membrane Stress, R = Bearing Stress.Several other fasteners on the remote strainer assembly were also analyzed.

The limiting fastener was the metric size M10 bolt that connects the reinforcing angle to the connection box u-plate. This bolt has a calculated shear stress of 135.8 MPa with an allowable shear stress of 177.0 MPa.Waterway Connectinng the Remote Strainer to the Recirculation Sump Table 3k2-5, below, provides the results of the structural analysis performed for the Unit 2 waterway and supports.Table 3k2-5 Waterway Structural Analysis Results Allowable Calculated Element Governing Stress, Stress, IR (1)Load Case(s) ksi(3) ksi Shell 24.1 (M+B) 18.8 0.78 (3/8 in plate steel 2 .1 welded together to form waterway) 13.9 (S) 7.6 0.55 Waterway Flange 1 63.9 (T) 37.1 0.58 Bolts 36.6 (S) 13.5 0.37 Waterway Flange 1 24.1 (B) 23.9 0.99 Plates Structural Bolts at 3 49.3 (T) 0.25 0.005 Crane Wall Flange 1 36.6 (S) 25.6 0.70 Waterway Support Members 3 22.5 (M+B) 6.98 0.31 Waterway Support 1 36.6 (S) 22.5 0.61 Bolts Support Base 3 24.3 (B) 15.3 0.63 Plates Welds for Waterway and Waewyad3,5 5(4) 0.74 (2)Supports Bounding Case (1)(2)(3)(4)IR = interaction ratio, i.e., the calculated stress divided by the allowable stress.Bounding interaction ratio (coefficient) for all welds. The limiting element was the support plate weld.T = Tension Stress, S = Shear Stress, B = Bending Stress, M = Membrane Stress.Load Case 5 was a special case to evaluate uplift loads, 0.95DW + DBE (vertical).

Attachment 3 to AEP:NRC:8054-02 Page 271 I&M Response to Information Item 3.k.3 I&M performed an evaluation of the Unit 1 and Unit 2 main strainer, main strainer vent line, remote strainer and waterway, and the DI at the flood-up overflow wall hole for susceptibility to jet impingement and pipe whip from HELBs inside containment (Reference 113). This evaluation did not consider a HELB from the RCS loop piping since I&M has been granted a LBB exemption for this piping, per Reference 21.Other HELBs in containment were considered for their potential impact on the recirculation sump components (Reference 113). The break locations that were considered are identified in References 39 and 112. Per the CNP UFSAR, Section 5.2.2.7, the effect of jet impingement is limited to within ten diameters of the break location.

All applicable HELBs were determined to be more than ten pipe diameters from the recirculation sump components.

The break locations were also evaluated to determine if pipe whip from the break could impact the sump components.

The evaluation determined that none of these breaks would result in a pipe whip that would impact the sump components.

Therecirculation sump strainers are protected from externally generated missiles since they are located within the Containment building which is designed to withstand these missiles (UFSAR Section 5.1). The design criteria for all systems structures and components within containment is that their failure can not result in missile generation that could potentially impact required safety related equipment (UFSAR Section 1.4). The accident analysis section of UFSAR Section 14.2.6.1.1.6) considers the ejection of a Control Rod Drive mechanism from the top of the reactor vessel. This-event is postulated to occur in a section of containment for which a missile shield is provided and is significantly separated from the location of the proposed recirculation sump strainers.

I&M Response to Information Item 3.k.4 I&M is not crediting a backflushing strategy for mitigating an excessive strainer head loss condition.

Regarding reverse flow through a strainer, the information provided in the response to Information Item 3.k.2 included evaluation of reverse flow through the remote strainer and waterway during the pool fill condition.

The evaluation determined that the remote strainer and waterway had adequate structural capability, with margin, to withstand reverse flow.

Attachment 3 to AEP:NRC:8054-02 Page 272 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 3.1.1 I&M evaluated the flowpaths associated with the recirculation function inside containment.

Considered in this evaluation were those flow paths considered in the containment sump inventory analysis (Reference 32), and those flow paths associated with the location of recirculation sump strainers both inside and outside the crane wall.The debris transport analysis (Reference

28) also performed an evaluation of the potential choke points in the recirculation transport paths.The potential choke points identified in the evaluation of the flow paths were as follows:* 10 in diameter openings in the flood-up overflow wall* CEQ fan room drains* Ice Condenser drains* Refueling canal drains The choke points were evaluated as described below.10 in Diameter Openings in the Flood-Up Overflow Wall The 10 in diameter openings in the flood-up overflow wall were considered since the blockage of these openings could result in insufficient supply of water to the remote Attachment 3 to AEP:NRC:8054-02 Page 273 strainer in the event the main strainer became blocked with debris to the extent that the majority of the flow being supplied to the recirculation sump would be from the remote strainer.

As a result, the. openings in the flood-up overflow wall were determined to be essential for maintaining adequate core and containment cooling.CEQ Fan Room Drains The CEQ fan room drains consist of one drain in the east CEQ fan room and two drains in the west CEQ fan room. The CEQ fan room drains in Unit 1 drain to the annulus (pipe tunnel) sump and the CEQ fan room drains in Unit 2 drain to the lower containment sump inside the crane wall (adjacent to the recirculation sump). Approximately 127 gpm of the upper containment CTS flow would flow through the CEQ fan room drains (References 156 and 157). Debris blockage of these drain lines would result in decreasing the sump inventory over time, reducing the minimum containment sump water level, decreasing the available head for flow through the main and remote strainers.

As a result, these drains were determined to be essential for maintaining adequate core and containment cooling.Ice Condenser Drains There are 21 drains in the ice condenser of each unit. If one or more of these drains were to become obstructed by debris, there are sufficient drains available to drain the ice melt water from the ice condenser.

By design, there are no obstructions between drain locations that would prevent ice melt water from flowing to available drains.Refueling Canal Drains There are three refueling canal drains with two of the drains having a 12 in diameter and the remaining drain having a 10 in -diameter.

These drains are of sufficient diameter and quantity that blockage of the necessary openings was determined to be unlikely.Additionally, an analysis was performed (Reference 141) that demonstrated that any two of the three drains provided excess capability for draining CTS water in upper containment to the containment sump pool.I&M Response to Information Item 3.1.2 The measures taken by I&M to mitigate the potential choke points determined to be essential to the success of maintaining core and containment cooling are as described below.10 in Diameter Openings in the Flood-Up Overflow Wall For the flood-up overflow wall openings, the modifications associated with the resolution of GL 2004-02 included installation of a DI on the loop compartment side of the flood-up overflow wall openings.

The response to Information Item 3.j.1 provides additional information regarding this DI. The capability of the DI to pass the necessary flow was determined as described in the response to Information Items 3.e.3 and 3.e.4.Additionally, the radiation shields installed on the annulus side of the flood-up overflow Attachment 3 to AEP:NRC:8054-02 Page 274 wall were modified to further assure adequate flow through the 10 in opening in the wall.The lower 2 in of the shields was removed to allow fine and small debris to be more readily swept away from the openings.

This modification was performed even though the radiation shields had sufficient flow area on the sides of the shield areas to pass the required flow and allow debris to be swept from the area of the openings.

To ensure the flood-up overflow wall flow openings and flow path remain available, associated Surveillance Requirements have been added to the TS as documented in References 11, 12, and 14. The associated Surveillance Requirements ensure that there is no debris that could block the flow openings and that the DI is installed and free of structural distress.CEQ Fan Room Drains DIs have been installed over the CEQ fan room drain openings to prevent washdown debris from blocking the drains. The response to Information Item 3.j.1 provides additional information regarding these DIs. Additionally, the CEQ fan room drain lines in both units have had their drain covers and check valve internals removed to assure adequate transfer of water from the fan rooms to the containment sump pool. In Unit 2, the CEQ fan room drain is routed to the lower containment sump. A flow opening was created in the lower containment sump to ensure the water that drains to the sump will be able to enter the containment pool. In Unit 1, the CEQ fan room drains are routed to the pipe tunnel sump, outside the crane wall, which has an existing opening. To ensure the CEQ Fan Room paths remain available, associated Surveillance Requirements have been added to the TS as documented in References 11, 12, and 14. The associated Surveillance Requirements ensure there is no debris that could block the drains, the DIs are installed and free of structural distress, and the flow openings in the associated containment sump are not obstructed.

Ice Condenser Drains and Refueling Canal Drains The ice condenser drains and the refueling canal drains both have associated Surveillance Requirements for ensuring these flow paths are available.

I&M Response to Information Item 3.1.3 An evaluation was made of the potential holdup of water in the refueling cavity as documented in Reference

32. This evaluation conservatively determined that approximately 9,500 gallons of water would be withheld from the containment pool in the refueling cavity. As also documented in Reference 32, approximately 117,795 gallons of water would be held up in the reactor cavity from, the floor elevation to the top of the flood-up overflow wall. There are small communication paths between the reactor cavity and the loop compartment through the primary shield wall starting at approximately 1 ft above the floor of the loop compartment.

Once water level in the loop compartment reached this point, a portion of the sump pool would flow into the reactor cavity.For the DI at the flood-up overflow wall, the overall height of the perforated vertical sections is approximately 34 in with a 6 in opening between the vertical section and the top cover. The flow capability of the DI was evaluated as documented in the debris Attachment 3 to AEP:NRC:8054-02 Page 275 transport analysis (Reference

28) and is described in the response to Information Item 3.e.4. As described in the response to Information Item 3.j.1, the previously existing 7 in curb at the entrance to the recirculation sump was removed and the installed main strainer support base created an approximate 4 in curb. Additionally, there is an approximate 12 in curb on the annulus side of the flood-up overflow wall openings.Since CNP's minimum water level is substantially above the elevations of these curbs, the impact of these curbs with respect to water hold up, is judged to be negligible.

I&M Response to Information Item 3.1.4 The potential blockage of the refueling canal drains, including likelihood of blockage and amount of expected holdup, has been provided in the response to Information Item 3.1.2.

Attachment 3 to AEP:NRC:8054-02 Page 276 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 I&M has completed an evaluation of ex-vessel recirculation path blockage from debris laden fluid in accordance with WCAP-16406-P, Revision 0 (Reference 23). This evaluation considered potential blockage in valves, orifices, heat exchangers, etc. The evaluations of downstream effects within pumps, the reactor vessel, and the reactor core will be completed in accordance with the schedule described in References 15 and 16.I&M has performed a review of the differences between WCAP-16406-P, Revision 0 and Revision 1 (Reference 114) with regard to ex-vessel blockage, and has-also reviewed the Safety Evaluation Report (Reference 111) issued by the NRC for WCAP-1 6406-P, Revision 1. I&M has determined that the evaluation of ex-vessel recirculation path'blockage that was performed for CNP.Unit 1 and Unit 2 per WCAP-16406-P, Revision 0 Attachment 3 to AEP:NRC:8054-02 Page 277 meets the guidance requirements of WCAP-16406-P, Revision 1, and the NRC Safety Evaluation Report.The evaluation performed for the ex-vessel blockage was performed by Enercon, under contract to Westinghouse (Reference 29). The evaluation was a bounding evaluation for Unit 1 and Unit 2 using a detailed methodology to evaluate systems, components, and instrumentation that could be affected by debris that could pass through the recirculation sump strainers.

Documents from both units were reviewed and the most limiting condition or component was used for the evaluation.

The recirculation flow path alignments were reviewed to ensure that all required flow paths and components impacted by debris passing through the strainers were evaluated.

Once the flow paths ,and components were identified, the size of the limiting flow passageways was compared to the size of the debris that could pass through an assumed 1/8 in strainer opening. This assumed strainer opening bounds the nominal opening size in the CNP strainers of 1/12 in (2.1 mm), and bounds the maximum opening size of 3/32 in (2.4 mm)at the dimple areas in the strainer pockets. Additionally, the procedure (Reference 115)that implements TS Surveillance Requirements for inspecting the recirculation sump and its connected components ensures that there are no gaps or openings that would allow bypass of debris greater than the strainer opening. The specific inspection criteria in that procedure are as follows:* All gaps shall be less than 1.5 mm (-0.060 in).* All gaps between 1.0 mm (-0.040 in) and 1.5 mm shall be no longer than 2 in and there shall be at least 1/2 in between such gaps.* There shall be no more than a total of 4 in of 1.0 mm to 1.5 mm gap in any 1 ft running length of interface.

Therefore, the size of the strainer openings assumed in the evaluation (1/8 in) was conservative with respect to the actual size that could pass through or bypass the installed strainers.

A determination of the expected velocity in the various ex-vessel flow paths was also performed to ensure that sufficient velocity existed to prevent debris settling and accumulation that could lead to blockage.The ex-vessel wear, abrasion, erosion, and pump blockage evaluations are being performed for CNP by S&L utilizing the guidance of WCAP-16406-P, Revision 1, as clarified and accepted by the associated NRC Safety Evaluation Report.I&M Response to Information Item 3.m.2 The evaluation described in the response to Information Item 3.m.1 determined that there are no locations where blockage from debris laden fluid would occur. The potentially limiting components within the recirculation flow path were determined to be instrument lines, throttle valves, orifices, and spray nozzles. The evaluation of the instrument lines determined that there were none that were installed below the centerline of the instrumented pipe or involved flow through the associated instruments.

The evaluation of the orifices determined that their openings were substantially larger than the conservatively assumed maximum particle size of 1/4 in. The evaluation of the spray nozzles in the CTS and RHR systems determined that the minimum opening dimension Attachment 3 to AEP:NRC:8054-02 Page 278 was 3/8 in, which is also larger than the conservatively assumed maximum particle size of 1/4 in. The evaluation of the six throttle valves that exist in the intermediate head and high head injection flow paths determined that these valves are controlled by procedures (References 116 through 119) which limit the opening inside the valve to ensure that a 1/4 in particle will pass through the valves. The current limit on the position of these throttle vales ensures that there is an opening of at least 0.354 in (approximately).

The results of the ex-vessel wear, abrasion, erosion, and pump blockage evaluations will be provided in the final response to GL 2004-02, submitted in accordance with the schedule provided in the response to Information Item 2.I&M Response to Information Item 3.m.3 I&M has not made any design or operational changes as a result of the ex-vessel blockage evaluation that has been completed.

Any design or operational changes as a result of the remaining ex-vessel blockage evaluation will be provided in the final response to GL 2004-02, submitted in accordance with the schedule provided in the response to Information Item 2.

Attachment 3 to AEP:NRC:8054 Page 279 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 I&M is currently performing an evaluation of downstream effects for the fuel and reactor vessel per the guidance contained within WCAP-16793 (Reference

88) with consideration of NRC staff comments on that document, including the letter from the NRC to 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.... (Reference 120). I&M's evaluation is being performed by Westinghouse.

Preliminary results indicate the CNP Unit 1 and Unit 2 do not have a core cooling concern as a result of the potential debris ingestion into the reactor vessel and core. The evaluations of downstream effects within the fuel and reactor vessel will be completed in accordance with the schedule described in References 15 and 16. The results of that evaluation will be provided in the final response to GL 2004-02, submitted in accordance with the schedule provided in the response to Information Item 2.

Attachment 3 to AEP:NRC:8054-02 Page 280 NRC Information Item 3.o Chemical Effects I&M has restructured this section to include those items from the content guide (Reference 9)and the review guidance (Reference 144) 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 I 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..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 Attachment 3 to AEP:NRC:8054-02 Page 281 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 and justify why the plant-specific refinement is valid.b) For crediting inhibition of aluminum that is not submerged, licensees should provide the substantiation for the following:

(1) the threshold concentration of silica or phosphate needed to passivate aluminum, (2) the time needed to reach a phosphate or silicate level in the pool that would- result in aluminum passivation, and (3) the amount of containment spray time (following the achieved threshold of chemicals) before aluminum that is sprayed is assumed to be 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.

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.

Attachment 3 to AEP:NRC:8054-02 Page 282 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.I&M Response to Information Item 3.o.1 Backgqround I&M has performed chemical effects testing at the strainer vendor, CCI, using a methodology aligned with WCAP-16530-NP (Reference 24), and a 30-day integrated chemical effects test at the Vuez facility, through ALION. The final test report for the Vuez facility testing has not been received by I&M. The findings documented in that report will be discussed in the final response to GL 2004-02 in accordance with the schedule provided in the response to Information Item 2.The remainder of the response in this section provides the applicable information for the chemical effects testing performed at CCI.

Attachment 3 to AEP:NRC:8054-02 Page 283 The testing performed at CCI was conducted in the latter half of 2007 using the MFTL with CNP strainer cartridges that included dimpled pockets. A description of the MFTL and test setup is provided below.The MFTL configuration used for CNP testing consisted of two CNP strainer cartridges, each having 20 pockets, and three Plexiglas modules. Refer to Figure 3o1-1, below for a sketch showing the arrangement.

To replicate the 4 in curb that exists at the CNP main strainer installation, the bottom row of pockets (four) were blocked off and a false floor with an approach ramp was installed in front of the strainer cartridges.

Figure 3o1-1 MFTL Configuration Used for CNP Testing (false floor not shown)The MFTL was equipped with a pump having a capacity of 200 m 3/hr, a differential pressure flow measurement device, and a temperature measurement device.The configuration of the MFTL was such that the testing applied only to the CNP main strainer.The other difference between the test setup and the CNP configuration was that the MFTL test configuration used a non-vented outlet from the strainer, whereas the outlet of the CNP strainer is vented.Two different tests were performed to determine chemical effects impacts on the recirculation sump strainers debris bed. One test was performed for the DEGB and one test was performed for the DGBS. Since only the equivalent of the CNP main strainer could be tested, the head Attachment 3 to AEP:NRC:8054-02 Page 284 loss results cannot be directly used for determination of an overall head loss including chemical effects. The response to Information Item 3.o.15.a provides a discussion of application of the chemical effects test results to I&M's resolution of strainer head loss.The test strainer area was used to determine the scaling factor for the testing. This scaling factor was 19.2, for both flow and strainer area. The assumed plant strainer area was 850 ft 2 , which provides 50 ft 2 of sacrificial strainer area. The flow rate used for the testing was 114.90 m 3/hr, which is representative of a plant flow rate of 9,720 gpm. This flow rate is the value (determined as documented in Reference

27) that would exist if the main strainer was 90%blocked. The use of this flow rate is conservative in that it would produce a higher head loss for a given debris and chemical precipitate loading. Testing performed on the large scale test loop as described in the responses to Information Items 3.f.4 and 3.f.10 demonstrate that the system head loss would be substantially below the values seen during the MFTL testing. Due to the CNP main and remote strainer configuration, as the head loss on the main strainer increases, the flow through the main strainer would decrease and the flow through the less heavily loaded remote strainer would increase.

Debris preparation for the MFTL testing was the same as that described for the large scale testing in the response to Information Item 3.f.4.The downstream effects from the chemical precipitates are currently being evaluated in accordance with WCAP-16793-NP (Reference 88). The results of this evaluation will be provided in the final response to GL 2004-02, per the schedule provided in the response to Information Item 2.The debris quantities used for both the DEGB and DGBS chemical effects test are provided in Figure 3ol-2, below.Figure 3ol-2 Debris Quantities for Head Loss Tests Debris Name Unit Mass (SI) Mass (SI)(SI) Test I (DEGB) Test 2 (DGBS)Fibrous Debris Nukon (kg) 0.447 0.447 Particulate Debris RMI (kg) 17.590 9.466 CalSil fkt) 3.402 0.855 Marinite I (kg) 0.002 0.000 Wollastonite (kg) 0.006 0.004 Min-K (kg) 0.016 0.000 Unqual Non-OEM Epoxy (kg) 0.196 0.083 Unqual Non-OEM Alkyd (kg) 0.049 0.249 Stone Flour (kg) 17.766 14.564 The chemicals and quantities used for the DEGB chemical effects test are 3o1-1, below.provided in Table Attachment 3 to AEP:NRC:8054-02 Page 285 Table 3o1-1 Chemical Addition Table DEGB 100% Chemical Addition Amount DEGB Test, kg Boric Acid 25.311 Sodium Tetraborate (borax) 12.753 Sodium Aluminate Solution 36% 35.666 Calcium Chloride Solution 34% 39.550 Sodium Silicate Solution 38% 26.926 The chemicals and quantities used for the DGBS chemical effects test are provided in Table 3ol-2, below.Table 3ol-2 Chemical Addition Table DGBS 100% Chemical Addition Amount DGBS Test, kg Boric Acid 25.311 Sodium Tetraborate (borax) 12.753 Sodium Aluminate Solution 36% 35.666 Calcium Chloride Solution 34% 39.550 Sodium Silicate Solution38%

26.926 The test sequences used for the DEGB and DGBS tests are provided in Figures 3ol-3 and Figures 3ol-4, below. The tables in these figures provide the parameters monitored and data collected during the tests, and the time sequence for the tests. The first steps in these tests were to establish the base chemistry in the loop through addition of boric acid and sodium tetraborate.

The debris was then added to establish the debris bed in the test strainer.

The tests were then allowed to run overnight prior to the chemical'additions.

The chemical additions were then performed incrementally starting at 40%, increasing to 70%, and then to 100% of the total'calculated quantity.

The tests were then allowed to run overnight.

The chemical quantities for the DEGB test were then incrementally increased to 120% and 140% of the total calculated quantity.

For the DGBS test, an error in the test specification provided the quantities of chemicals required for the DEGB test to be added to the DGBS test (as provided in Table 3ol-2). This was discovered after the 120% sodium aluminate solution had been added to the test loop. For the DGBS test, the actual 100% quantity of calcium chloride solution that should have been added was 13.796 kg, and the actual 100% quantity of sodium silicate solution that should have been added was 9.031 kg. As a result, the actual percentage of calcium chloride solution added to the test was 287%, and the actual percentage of sodium silicate solution added to the test was 298%. The sodium aluminate was correctly added to the 140% value.After the final chemicals were added to the test loop, the tests were allowed to run continuously for nearly four days. Once the test termination criteria, less than 1% increase in head loss in two consecutive 30 minute periods was verified, a flow reduction sequence was initiated for both tests. The flow reductions were equivalent to removing a CTS pump from service, allowing head loss to achieve a reasonably stable value, and then reducing flow again, equivalent to removing an RHR pump from service. For the DEGB test, an additional flow reduction step Attachment 3 to AEP:NRC:8054-02 Page 286 equivalent to removing another CTS pump was performed.

After a reasonably stable head loss was achieved following the flow reductions, the tests were terminated.

Figure 3ol-3 DEGB Test Data Flow Rate Time Date Debris Temp Ap Remarks (m 3/h) (%) C (mbar)0.0 08:50 18.09. 0 16.9 0.0 level 4cm over cartridges 114.9 09:10 0 16.0 3.0 Boron added 114.9 11:00 0 17.7 3.0 Borax added 114.5 13:50 50 20.1 74.0 114.8 13:53 100 20.1 174.3 debris added 114.9 16:00 100 22.1 87.0 114.9 08:20 19.09. 100 30.4 63.5 114.9 09:20 100 31.4 70.5 40% Aluminat 114.9 10:00 100 31.4 74.5 40% Calcium Chlorid 114.9 10:30 100 31.8 82.7 40% Silicate 114.9 12:10 100 32.7 83.3 70% Aluminat 114.9 12:40 100 32.8 84.2 70% Calcium Chloride 114.9 14:10 100 33.2 86.6 70% Silicate 114.9 14:48 100 33.7 87.0 100% Aluminat 114.9 15:22 100 33.7 87.2 100% Calcium Chloride 114.9 16:57 100 33.8 89.4 100% Silicate 114.9 08:05 20.09. 100 34.6 82.2 114.9 09:05 100 34.1 82.0 120% Aluminat 114.9 09:40 100 35.5 82.0 120% Calcium Chloride 114.9 10:15 100 35.5 82.5 120% Silicate 114.9 11:15 1 100 35.5 82.0 5.163 kg Nitric Acid 114.9 13:30 100 35.7 81.7 140% Aluminat 114.9 14"02 100 35.7 81.6 140% Calcium Chloride 114.9 14:39 ' 100 35.7 82.5 140% Silicate 114.9 15:39 100 35.7 82.3 2.916 kq Nitric Acid 114.9 07:50 21.09. 100 35.7 83.0 114.9 07:05 24.09. 100 39.3 84.0 run over weekend, test end 88.0 07:10 100 39.3 51.2 flow rate 87.8 m 3/h 57.5 08:55 100 37.5 22.6 flow rate 57.5 m 3/h 30.3 10:00 100 37.4 7.2 flow rate 30.3 m 3/h Attachment 3 to AEP:NRC:8054-02 Page 287 Figure 3ol-4 DGBS Test Data Flow Rate Time Date Debris Temp Ap Remarks (m 3/h) (%) t°C) (mbar)0 08:00 25.09. 0 17.0 0.0 level 4cm over cartridges 114.9 09:30 0 20.0 2.6 Boron added 114.9 11:20 0 20.2 2.7 Borax added 114.9 14:05 0 22.8 2.7 clean head loss 114.6 14:20 33 23.0 22.0 114.6 14:30 66 23.1 153-0 114.7 14:35 100 23.2 219.0 debrisadded 114.9 15:05 100 23.6 175.5 114.9 07:45 26.09. 100 32.0 101.1 115.2 08:40 100 32.8 1137 40% Alurninat 115 09:15 100 33.0 117-5 40% Calcium Chlorid 115 10:45 100 33.3 129.5 40% Silicate 115 11:15 100 33.8 132.2 70% Aluminat 115 11:47 100 33.9 133.7 70% Calcium Chlorid 115 13:17 100 34.3 138.5 70% Silicate 115 13:51 100 34.7 139.0 100% Aluminat 115 14:25 100 35.0 139-5 100% Calcium Chloride 115 14:57 100 35.1 141.6. 100% Silicate 115 15:57 100 35.2 141-6 pH 9.1, 3.500kg NitricAcid 115 17:00 100 35.2 141 9 pH 8.8 115 07:55 27.09. 100 36.4 142-9 pH 8.8 115 08:20 100 36.6 142.9 120% Aluminate 115 08:55 100 36.6 142.8 pH 9.1, 3.000 kg Nitric Acid 115.1 10:41 100 36.8 143.3 140% Aluminate 115 11:15 100 37.0 143.5 pH 9.2, 3.500 kg NitricAcid 115 16:00 100 37.3 143.3 pH 8.9 115 08:15 28.09. 100 37.0 143.0 pH 8.9 115 08:15 01.10. 100 38.8 142.0 run over weekend, testend 87.8 08:20 100 37.5 84.9 flow rate 87.8 m 3/h 57.8 09:07 1 1 100 37.3 38.0 flow rate 57.5 m 3 lh As described above, the test loops were operated overnight following the debris additions.

Prior to the chemical additions the following morning, it was noted that the water in the test loop had high visual clarity with little to no debris settling in the test loop. These tests, like the large scale)

Attachment 3 to AEP:NRC:8054-02 Page 288 tests described in the response to Information Item 3.f.4, demonstrated that the CNP debris bed is very effective at filtering particulates from the pool water in a relatively short period of time.This clarity can be seen in the pictures contained in Figures 3ol-5 and 3ol-6, below.ure 3o1-5 DEGB MFTL Prior to Chemical Addition Attachment 3 to AEP:NRC:8054-02 Page 289 For both the DEGB and the DGBS tests, significant quantities of chemical precipitate were generated.

This can be seen in the pictures provided in Figures 3ol -7 through 3ol -11, below.Fl ure 3o1-7 DEGB MFTL Post Test Precipitate Accumulation on Test Strainer Ut~ rJJ3i Attachment 3 to AEP:NRC:8054-02 FinurA 3nl1-R DIFrB MFTL r Page 290 Attachment 3 to AEP:NRC:8054-02 Page 291 Figure 3ol-9 DEGB MFTL Debris Accumulation in Test Module After Removal from Test Attachment 3 to AEP:NRC:8054-02 Page 292 Attachment 3 to AEP:NRC:8054-02 Page 293 Figure 3o1-11 DGBS MFTL Debris Accumulation in Test Module After Removal from Test Attachment 3 to AEP:NRC:8054-02 Page 294 I&M Response to Information Item 3.o.2.a I&M did not perform a simplified chemical effects analysis since no credit is being taken for bare ,strainer area.I&M Response to Information Item 3.o.3.a The debris from the selected DEGB and DGBS are considered the worst case debris loads from a chemical effects perspective because 1) these breaks generate the greatest quantities of calcium silicate based materials that are available for transport to the main and remote strainers, and 2) CNP does not have any fibrous debris other than latent debris. The calcium silicate based materials have been shown to produce higher head losses than tests conducted without it where a fiber thin bed cannot be formed on its own (Reference 145). Additionally, since the CNP calcium silicate, quantities are not large enough to create inhibition effects as evaluated in WCAP-16785-NP (Reference 146), with the maximum containment water volume used for this analysis, they will not contribute to a reduction in chemical precipitates that calculations indicate would be formed in the post accident containment sump pool.I&M Response to Information Item 3.o.4.a The chemical effects analysis for CNP determined both the quantity of chemicals which are dissolved in the post-LOCA sump as well as the predicted quantity of precipitate present in the post-LOCA sump using the methodology provided in Reference

24. The inputs to the chemical effects analysis are provided below.Containment Materials Contributinq to Chemical Precipitate Generation Table 3o4a-1, below, provides the containment debris materials and quantities considered in the.chemical effects evaluation (Reference 147).Table 3o4a-1 Containment Debris Sources Considered in Chemical Effects Evaluation Insulation Debris Density, Loop 4 Alternate lb/ft 3 Break, Loop 4 lb Break, lb Cal-Sil 14.5 511.9 118.9 Marinite I (calcium silicate) 46 0.4 0 Marinite 36 (calcium silicate) 36 3.6 2.7 Total Marinite (calculated) 14.5 4.0 2.7 Min-K 16 1.6 0 Other Debris Latent Debris 200 lb Latent debris fiber 15% 30 lb Latent debris particulate (dust & dirt) 85% 170 lb Attachment 3 to AEP:NRC:8054-02 Page 295 Materials not considered in the evaluation were those evaluated in Reference 24 as not contributing to the quantity of dissolved chemicals, such as RMI, epoxy coatings, RCP motor oil, other organics, and copper.Containment AtmosDhere TempDerature Profile Figure 3o4a-1, below, provides the lower containment temperature time history. This figure is from CNP's UFSAR (Figure 14.3.4-8).

Figure 3o4a-1 Lower Containment Temperature 230 220 210_ 200*. 190 d 180 2YJ 220 210 200 190 1J80 170 170 SGO lime (S)The containment temperature response beyond 100,000 seconds is discussed"Assumptions" section provided later in the response to this information item.in the Sumo Water TemDerature Profile Figure 3o4a-2, below, provides the containment sump temperature time history. This figure is from CNP's UFSAR (Figure 14.3.4-9).

Attachment 3 to AEP:NRC:8054-02 Page 296 Figure 3o4a-2 Containment Sump Temperature 690 180 U--o 160 L-.0-E 150 H--140 130 ISO 1480 130 Time (s)The containment sump temperature response beyond 100,000 seconds is"Assumptions" section provided later in the response to this information item.discussed in the Ice Melt Profile Figure 3o4a-3 provides the ice condenser ice melt time history for the analysis.

This figure is from CNP's UFSAR (Figure 14.3.4-10).

Figure 3o4a-3 Ice Condenser Ice Melt Transient.25E+07 -_ _ _ _ _ __".2E+07-.15E407.1E+07 0 containment integrity.25E+07.2E+07 E.15E+07 -.1E+07, 500000 ILJ -l 10 All ice in the ice condenser is melted in approximately one hour.

Attachment 3 to AEP:NRC:8054-02 DH Time History and Water Volumes Page 297 Table 3o4a-2, below, provides .the pH values and supporting information considered and used for the chemical effects evaluation.

This information is from Reference 147.Table 3o4a-2 pH Time History & Water Volumes Beginning Spray pH 9.74 End of Injection

-Spray pH 9.91 End of Injection

-Sump pH 8.74 Start of Recirculation

-Time (minutes) 32.5 Start of Recirculation

-Spray pH 12.72 End of SAT Eduction -Time, min 37.5(1)End of SAT Eduction -Spray pH (high) 12.76 End of SAT Eduction -Spray pH (low) 8.93 Elapsed time at high pH, minutes, (calculated) 5.00 8-Hour -Sump and Spray pH 8.79 End of ice melt -Sump and Spray pH 8.91 CTS Minimum Flow 2942 gpm SI + RHR minimum Flow 4542 gpm RCS volume (maximum) 12,911 RCS density (maximum) 6.354 lb/gal RWST volume (maximum) 385,432 gal Accumulator (maximum) 29,052 gal SAT w/ normal isolation

-maximum delivered 4138 gal SAT wt% NaOH (minimum) 30 Wt%Density for 30 wt% NaOH 11.06 lb/gal Ice melt (minimum) 2,200,000 lb Refuel Canal 9,500 gal/A\ /----I I\k-I) value equals sum OT dZ.O minutes kstart OT recirculation) plus five minutes kelapsed time at nign prl).Containment Materials Contributinq to Chemical Effects Table 3o4a-3, below provides the quantity of materials, and whether they are submerged or subjected to containment spray in the Unit 1 and Unit 2 containments.

This list was developed from plant walkdowns and dimensions shown on design drawings (References 147 and 148).

Attachment 3 to AEP:NRC:8054-02 Page 298 Table 3o4a-3, Containment Materials Submerged Aluminum Metal (Below El. 614 ft) Mass, lb Area, ft 2 Electrical Equipment (Limit Switches) 1.5 0.44 Fans and Motors 2.31 3.67 Radiation Detectors 0.72 0.36 Miscellaneous Components 17.72 6.46 NSSS Components (NRI-32,-36,-41A thru -44B) -244.00 83.00 Located in Reactor Cavity TOTAL -Including Components in Reactor Cavity 266.25 93.93 TOTAL -Excluding NSSS Components in Reactor 22.25 10.93 Cavity Non-submerged Aluminum Metal (Above El. 614 ft) Mass, lb Area, ft7 Electrical Equipment 0.80 0.81 Radiation Detectors 0.03 0.06 Valve Components 8.00 2.47 Crane Components 1.05 0.72 Miscellaneous Components 22.97 9.33 NSSS Components (RCP Cooling Coils) 1,152.00 8,000.00 TOTAL 1,184.85 8,013.39 Uncoated Concrete (Exposed Concrete)

Area, ft 2 Submerged (Below El. 614 ft) 6,412.78 Non-submerged (Above El. 614 ft) 1,077.10 Zinc Coated Steel Area, ft 2 Galvanized Steel (Below El. 614 ft) 70,831.64 Cold Zinc Coated Steel (Below El. 614 ft) 330.98 Total submerged zinc coated steel 71,162.62 Galvanized Steel (Above El. 614 ft) 495,734.96 Cold Zinc Coated Steel (Above El. 614 ft) 8994.00 Total non-submerged zinc coated steel 504,728.96 Assumptions The assumptions considered for the chemical effects (Reference 147).evaluation included the following* For the purposes of the chemical dissolution rate, the sump mixing option in the spreadsheet, was used to determine if the concentration of the chemical being considered was based on a single source (e.g., calcium silicate) or all the sources. As the concentration Attachment 3 to AEP:NRC:8054-02 Page 299 increases, the dissolution rate decreases, therefore, it was conservative to assume a late start of mixing.* For purposes of the calculation, it was assumed that the sump was not mixed until eight hours after the event. This was a conservative assumption because delaying the start of mixing resulted in slightly greater dissolution by assuming lower concentrations of the dissolved material in the sump water and, therefore, a greater dissolution rate." The submerged material was assumed to be exposed to the containment temperature and containment spray pH for the first 32.5 minutes (1950 seconds), the maximum time at which recirculation begins. After 1950 seconds, the submerged material was modeled to be at the sump temperature and pH. This conservatively assumed the material in the sump was subject to the higher spray pH and temperature until recirculation begins.* All latent debris is assumed to be submerged.

The latent debris will be carried into the sump by the initial flow of water from the break and the containment spray. Therefore, it was reasonable to assume that all of the particulate concrete was submerged.

This is a conservative assumption because the maximum available calcium, silicon, and aluminum in the debris will be released to the water in the sump." It was assumed that the mass attributed to the submerged and non-submerged exposed concrete surfaces (excluding particulate concrete) was sufficiently high such that the dissolution of calcium, silicon, and aluminum from these materials was unlimited.

This is a conservative assumption.

The density of water was assumed to be 62.4 Ib/ft 3.The water released into the containment was computed in terms of mass, based on the density from the various sources and then converted into a volume. The WCAP-16530-NP spreadsheet required a volume and density of water, which is converted back to a mass in the spreadsheet." The latent particulate debris was conservatively assumed to be cement and the fiber was assumed to be insulation, in proportion (by mass) to the insulation debris.* After 100,000 seconds (27.8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months ), the temperature was assumed to drop linearly to 100°F over the next 30 days. This is a conservative assumption because the temperature is expected to drop to a lower temperature after 30,days." When determining the time-pH profile for the containment spray and the containment sump, a high pH was conservative.

Therefore, the pH at the end of ice melt was used for time greater than eight hours even though the end of ice melt can occur earlier. This is conservative since the end of ice melt pH is greater than the pH at eight hours.The reactor cavity was considered sequestered for this analysis.

Containment water does enter the reactor cavity. However, once in the reactor cavity, the water does not mix with the rest of containment.

The bottom of the reactor cavity is at elevation 567.3 ft and the spill over elevation is 610 ft. The sump water level is at elevation 614 ft. Since there are no other flows entering the reactor cavity that would cause the water in the cavity to mix with the rest of containment, it was acceptable to consider the reactor cavity and its components sequestered.

Attachment 3 to AEP:NRC:8054-02 Page 300 I&M Response to Information Item 3.o.5.a The strainer vendor, CCI, performed the WCAP-16530 based chemical effects testing. ALION performed a 30-day integrated chemical effects test in the Vuez large loop facility.

The response to Information Item 3.o.1 provides additional discussion of the Vuez testing.I&M Response to Information Item 3.o.6.a The chemical effects analysis performed for I&M used the spreadsheet based on WCAP-16530-NP to perform the calculation of the quantity of aluminum, calcium, and silicon released, and the quantity of precipitate expected to form in the containment sump. The spreadsheet used for the analysis was that distributed with the Westinghouse August 7, 2006 letter, OG-06-255 (Reference 159), with the error described in the August 28, 2006 letter OG-06-273 (Reference 160), corrected.

The chemical effects analysis performed for I&M, by S&L, made certain refinements to the base model spreadsheets, but did not take any exceptions to the model. These refinements are described below." The two worksheets for submerged and non-submerged aluminum categories were split into four worksheets:

Submerged aluminum metal Non-submerged aluminum metal Submerged thin aluminum Non-submerged thin aluminum The input for each group was the area and the mass of aluminum.

The additional worksheets were copies of the original worksheets.

This change allowed a more accurate determination of the mass of aluminum that dissolves by. removing the area of the aluminum that has completely dissolved from further consideration.

The worksheet for concrete was divided into three separate sets of worksheets:

Particulate concrete Submerged solid concrete Non-submerged solid concrete The particulate concrete was input as pounds and converted to an equivalent area.The additional worksheets were copies of the original worksheet.

This change allowed for more accurate determination of the mass of material that dissolves from the concrete.The worksheet for the particulate concrete was revised to limit the calcium, silicon, and aluminum from the particulate concrete to the amount of each element present in the concrete.

The mass fractions of calcium, silicon, and aluminum in concrete are:

Attachment 3 to AEP:NRC:8054-02 Page 301 calcium -11.87 wt %silicon -6.74 wt %aluminum.-

2.45 wt %This change limited the mass of each material that could dissolve from the particulate to no more than 100% of the material in the particulate concrete." The summary sheets (Results Table, Releases by Materials, Precipitate by Material, and Precipitate by Time) were revised to accommodate these changes.* An Input Preparation Worksheet was added and all inputs (Time, Temp, pH Input, Materials Input, and Materials Conversion) were linked to that page." A Results Worksheet was added. Results from other worksheets are linked to this worksheet and appropriate calculations and organization for use in this calculation are performed in this worksheet.

I&M Response to Information Item 3.o.6.b The type and maximum quantities of chemical precipitates predicted to form for the 30-day duration for both the DEGB and DGBS are provided in Table 3o6b-1, below.Table 3o6b-1 Ty pes and Quantities of Chemical Precipitates Formed for 30 Day Duration Precipitate

-Mass, g PDEGB DGBS Sodium Aluminum Silicate 202,070 67,802 Aluminum Oxyhydroxide 86,701 117,371 Total Precipitate 288,771 185,173 I&M Response to Information Item 3.o.7.a through 3.o.7.d The I&M chemical effects analysis did not utilize any of the refinements described in Reference 146.I&M Response to Information Item 3.o.8.a The one-hour settled volume for precipitate prepared with the same sequence as with the chemical injection performed during the chemical effects strainer testing was 88 ml (Reference 78). This test was performed in a 100 ml graduated cylinder with a height corresponding to the 100 ml mark of 18.8 cm.I&M Response to Information Item 3.o.8.b Table 3o8b-1, below, provides the quantity of chemicals injected into the MFTL during chemical effects testing for the DEGB and DGBS tests, and the quantity of the chemicals remaining in solution (Reference 78).

Attachment 3 to AEP:NRC:8054-02 Page 302 Table 3o8b-1 Chemicals Injected and Chemicals that Remained Dissolved DEGB DGBS Chemical Injected, Percentage Injected, Percentage ppm Precipitated ppm Precipitated Aluminum 1,600 100% 1,600 100%Calcium 2,700 89% 2,700 89%Silica 3,800 100% 3,800 100%I&M Response to Information Item 3.o.8.c For the DEGB test, the chemicals were added to 140% of the total calculated at increments of 40%, 70%, 100%, 120%, and 140%.For the DGBS test, the chemicals were added to 140% for aluminum, and 100% of the DEGB quantities for calcium and silica. As discussed in the response to Information Item 3.o.1, the quantities of chemicals to be added were the values for the DEGB test. The final quantities of calcium and silica that were added were 287% and 298%, respectively, of calcium chloride solution and sodium silicate solution.I&M Response to Information Item 3.o.9.a I&M did not perform testing that included the creation of surrogates outside the test loop.I&M Response to Information Items 3.o.10.a and 3.o.10.b I&M did not credit near-field settlement in any of their chemical effects testing.I&M Response to Information Item 3.o.11.a During the MFTL chemical effects testing, the only visible debris on the test flume floor was the RMI. The flow rate used for the testing prevented any of the other debris from settling on the test flume floor (Reference 77). As can be seen in Figures 3ol-7 through 3o1-11, there was chemical precipitate settlement on top of the strainer cartridge.

I&M Response to Information Item 3.o.11.b Precipitate settlement values were not obtained within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months of the start of the MFTL chemical effects tests.Laboratory bench tests were performed as documented in Reference

79. The bench testing that was performed was based on the chemical quantities associated with the DEGB. The one-hour precipitate settled volume was 88%.I&M Response to Information Item 3.o.12.a Attachment 3 to AEP:NRC:8054-02 Page 303 The test termination criteria was less than 1% change in 30 minutes for two consecutive 30 minute periods.I&M Response to Information Item 3.o.13.a Figures 3o13a-1 and 3o13a-2, below, provide the plots of the head loss for the DEGB and DGBS chemical effects tests, respectively.

Figure 3o13a-1 DEGB MFTL Chemical Effects Test Plot Test Trend, DC Cook Test 1, 18.- 24.09.2007 240 120 220- 110-Head Loss 200- Temperature 100 180 -Flow Rate 90 v 160 80, 140 70o-- 0 120 60 o100 50 L.-: 80 40 E4 60 30 40 20 20 10 0 0 0 ...P 4.1 ..v ...d P A4 A.4 ., ., ., .,.Tm .,e .,Q Time Attachment 3 to AEP:NRC:8054-02 Page 304 Figure 3o13a-2 DGBS MFTL Chemical Effects Test Plot Test Trend, DC Cook Test 2, 25.09. -01.10.2007 240 120 220 -Head Loss 110 200 Temperature 100 180 90 160 80 140 70 120 60 ,a, 100 50 -" 80 40 60 30 40- 20 20- 10 0 0., .b .0 416 4P .b\ k .0 %:,1.-..T e 01" d" ," K,, Kp -, -I ,VI q,q, -V ý" !v ! q," Y/" " V ," q ,- V Time As described in the response to Information Item 3.o. 1, the chemical effects testing performed in the MFTL at CCI was performed on the equivalent of the main strainer only. As a result, the measured head loss values cannot be used as a direct input to the maximum system head loss determination.

The results of this testing were used to establish an appropriate bump-up factor as described in the response to Information Item 3.0.15.a.I&M Response to Information Item 3.o.13.b I&M did not use any extrapolation methods for data analysis of the MFTL chemical effects test results.I&M Response to Information Item 3.o.14.a and 3.o.14.b I&M will provide a response to this item in accordance with the schedule provided in the response to Information Item 2, which reflects the extension granted per Reference

16. The test report for the 30-day integrated chemical effects test that was performed in the large loop at the Vuez facility has not been received from the vendor that performed the testing, ALION.

Attachment 3 to AEP:NRC:8054-02 Page 305 I&M Response to Information Item 3.o.15.a I&M intends to use a chemical effects bump-up factor of 1.7 times the maximum determined head loss obtained from the large scale testing for both the DEGB and DGBS cases. The maximum head loss observed from the large scale tests was reported in the response to Information Item 3.f.4 and 3.f.10. The response to Information Item 3.f.10 also provided information describing I&M's increase of the measured head loss values by a factor of 1.5 to account for testing uncertainties and to provide additional margin.As a result of the chemical additions to the fully developed, debris-only bed in the strainer, head loss increased by a factor of 1.43 for the DEGB test, and 1.53 for the DGBS test. This was based on the recorded data from the test which occurred at different test loop temperatures.

To provide consistency in establishing the true head loss increase, the head loss values were temperature normalized to 20 0 C. The results of these temperature-normalized head loss values are provided in Table 3o15a-1, below.Table 3o15a-1 MFTL Chemical Effects Head Loss Test Results Normalized to 20 0 C 20 0 C Adjusted Head Loss Values Test Debris with Ratio Debris-only Chemical Effects DEGB 2.67 ft H 2 0 3.83 ft H 2 0 1.43 DGBS 4.43 ft H 2 0 6.80 ft H 2 0 1.53 As a result of this normalization, a chemical effects bump-up factor will be used to establish the overall system head loss for CNP. The bump-up factor that will be applied is 1.7 for chemical effects. For the DEGB, the head loss for the recirculation sump strainers will be established at 2.67 ft H 2 0. For the DGBS, the head loss for the recirculation sump strainers will be established at 2.09 ft H 2 0.The basis for the acceptability of the use of the debris-only head loss increase factor was established as described in the response to Information Item 3.f.4. The basis for the acceptability of the chemical effects bump-up factor is provided below.As stated previously in the response to Information Item 3.o.1, the chemical effects testing was performed with an equivalent to only the main strainer.

The main strainer would be the most heavily loaded of the two strainers following an event, as predicted by the debris generation (Reference

26) and debris transport analyses (Reference 28). The 20 0 C normalized debris-only head loss for the DEGB chemical effects test was 2.67 ft H 2 0. For the DGBS chemical effects test, this head loss was 4.43 ft H 2 0. As determined in the response to Information Item 3.f.4, the 200C normalized maximum overall system head loss for the DEGB case was 1.046 ft H 2 0, and was 0.819 ft H 2 0 for the DGBS case.The effective head loss across the main strainer during the limiting large scale tests for the DEGB and DGBS case would be, by observation of the flow split between the main and remote strainer sections, significantly higher than the head loss across the remote strainer if a flow rate equivalent to the flow rate used for the MFTL chemical effects were applied to each strainer Attachment 3 to AEP:NRC:8054-02 Page 306 section. Using the flow propeller measurements provided in Figure 3f4-22, averaging the measurements for the main and remote strainers, the determined flow for the main strainer and remote strainer were 37.8% and 62.2%, respectively.

Since the MFTL testing was performed with a flow rate equivalent to 67.5% of the total system flow, the equivalent head loss for the main strainer in the large scale test at an equivalent flow rate of 67.5% can be determined by the square of the ratios of 67.5% to 37.8%. The resulting head loss for the large scale test for the main strainer only would be 3.002 ft H 2 0. This compares favorably with the DEGB MFTL debris-only head loss, normalized to 200C, of 2.67 ft.Using the same approach for the limiting DGBS large scale test, the main strainer only head loss would be 6.916 ft H 2 0. This is approximately a factor of one and a half higher than that measured in the MFTL DGBS test. Since the DGBS case, for both the large scale and MFTL tests, demonstrates that the head loss across the main strainer would be higher than it would be for the DEGB case, the plausible explanation is that the DGBS cases experience higher head loss due to having less RMI to effectively act as a filter.Both the large scale test and MFTL test were performed with the same debris materials.

As a result, the chemical effects precipitate would be expected to behave similarly if they could have been used in the large scale test loop.The remote strainer will be loaded with significantly less debris, including latent fiber, as established in the debris generation (Reference

26) and debris transport analyses (Reference 28). The remote strainer also has a larger effective surface area (1000 ft 2 vs 850 ft 2 for the main strainer).

Based on the information provided above, I&M considers the application of a conservative bump-up factor of 1.7, determined as a result of the MFTL chemical effects testing, to be applicable to the debris-only head loss values obtained in the large scale tests.Information Item 3.o Conclusion One of the other conservatisms applied to the determination of precipitate formed from the reaction between aluminum in containment and spray. The single greatest contributor to the sprayed aluminum material in containment was the RCP motor air cooler fins. These coolers are mounted on the RCP such that the cooler face is vertical with air flowing horizontally through the cooler. Only one face of each cooler (2 per RCP) is exposed to the containment environment.

The top of the cooler is solid preventing introduction of CTS into the center of the cooler. The coolers are approximately 9 3/4 in deep by 26 7/8 in high by 73 3/4 in long, not counting the end bells. The tube bundle is approximately 6 1/2 in deep by 24 in high by 72 in long. The tubes bundle is recessed approximately 1 in from the face of the cooler. The coolers are approximately 20 ft below the CTS spray nozzles. By the time the spray gets to the vicinity of the coolers, most of the droplet direction will be vertical.

The spray will not be able to reach all of the aluminum fins in the coolers since there is nothing to force flow through the cooler. The chemical analysis assumed 100% participation of the fins with the spray. It can be reasonably concluded that 30% or more of the fins would be unaffected by spray. Refer to Figure 3o-CON-1 below for a photograph of the installed configuration.

Attachment 3 to AEP:NRC:8054-02 Page 307 3o-CON-1 RCP Motor Air Co4 As described in the response to Information Item 3.o.14, I&M has not received the test report for the 30-day Integrated Chemical Effects test. Until this test report is received and accepted by I&M, the final determination of the chemical effects impact on strainer head loss can not be established.

I&M has provided an expected and conservative maximum head loss contribution from chemical effects in the response to Information Item 3.o.15. I&M will provide the final determination of the impact of chemical effects on strainer head loss considering the CCI testing and ALION testing in the final response to GL 2004-02, which will be submitted in accordance with the schedule provided in the response to Information Item 2.

Attachment 3 to AEP:NRC:8054-02 Page 308 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 As detailed below, the licensing bases changes supporting resolution of the concerns identified in GL 2004-02 consist of UFSAR changes associated with plant modifications, TS changes to assure operability of required components, and licensing basis changes associated with the post accident debris mechanistic evaluation described in this letter.UFSAR Changes Associated With Plant Modifications The UFSAR changes associated with the plant modifications identified in the response to Information Item 3.j.1 are described below. The 50.59 evaluation dates for these UFSAR changes have been provided as requested in NRC Information Item 3.p. However, these dates do not reflect the dates that the UFSAR changes have been or will be made effective.

Therefore, the status of the UFSAR changes has also been included.UFSAR Section 6.2, "Emergency Core Cooling Systems," and Section 6.3, "Containment Spray Systems," were revised to reflect replacement of the previously installed trash racks and screens at the entrance to the recirculation sump with the new pocket-type strainer.

The Unit 1 50.59 evaluation was completed August 29, 2006. The Unit 2 50.59 evaluation was completed May 2, 2007. These UFSAR changes have been made effective.

UFSAR Figure 6.2-1A, "Emergency Core Cooling System (RHR) Units No. 1 or 2," and UFSAR Figure 9.3-1, "Emergency Core Cooling (RHR)," were revised to reflect replacement of the ,previously installed trash racks and screens at the entrance to the recirculation sump with the*new pocket-type strainer, and to delete the pipe connecting the lower containment sump to the recirculation sump since this pipe has been capped. The Unit 1 50.59 evaluation was completed August 29, 2006. The Unit 2 50.59 evaluation was completed May 2, 2007. These UFSAR changes have been made effective.

Attachment 3 to AEP:NRC:8054-02 Page 309 UFSAR Section 6.2 was revised to remove details regarding the pipe connecting the recirculation sump to the lower containment sump since this pipe has been capped. The Unit 1 50.59 evaluation was completed August 29, 2006. The Unit 2 50.59 evaluation was completed May 2, 2007. These UFSAR changes have been made effective.

UFSAR Section 6.2 and Section 6.3 were revised to reflect installation of a new remote strainer.The Unit 1 50.59 evaluation was completed January 10, 2008. The Unit 2 50.59 evaluation was completed September 10, 2007. The UFSAR changes for Unit 2 have been made effective.

The UFSAR changes for Unit 1 will be made effective prior to restart from the Spring 2008 RFO in accordance with the extension approved by Reference 16.UFSAR Figure 6.2-1A and UFSAR Figure 9.3-1 were revised to depict the addition,of the remote strainer.

The Unit 1 50.59 evaluation was completed January 10, 2008. The Unit 2 50.59 evaluation was completed September 10, 2007. The UFSAR changes for Unit 2 have been made effective.

The UFSAR changes for Unit 1 will be made effective prior to restart from the Spring 2008 RFO, in accordance with the extension approved by Reference 16.UFSAR Section 6.3.2, "System Design," was revised to reflect the new level switches which were installed inside the recirculation sump. The Unit 1 50.59 evaluation was completed August 29, 2006. The Unit 2 50.59 evaluation was completed May 2, 2007. These UFSAR changes have been made effective.

UFSAR Section 7.8, "Post Accident Monitoring," was revised to reflect the RG 1.97 classification of the new level switches which were installed inside the recirculation sump for Unit 2. The .UFSAR change for Unit 2 has been made effective.

UFSAR Section 7.8 will be revised for Unit 1 following implementation of as'sociated TS changes described below, but prior to restart from the Spring 2008 RFO. These UFSAR changes were/will be evaluated under 10 CFR 50.71(e).UFSAR Unit 1 Section 14.3.4.1.3.1.1.e, "Effect of Steam Bypass," and Section 14.3.9.1,"Accident Description," (which apply to both units) were revised to reflect the removal of the internals from the check valves installed on the west CEQ fan room drain lines in Unit 2. The 50.59 evaluation was completed September 10, 2007. These UFSAR changes have been made effective.

TS Changes A license amendment request for changes to the TS to support the resolution of concerns identified in GL 2004-02 was submitted to the NRC by Reference 11 on June 27, 2007. The NRC approved the license amendment by Reference 14 on October 18, 2007. The approved TS changes are summarized below.TS Section 3.6.14, "Containment Recirculation Drains," was revised to ensure the availability of two flow paths needed to assure adequate water level- in the recirculation sump following a LOCA.TS Table 3.3.3-1, "Post Accident Monitoring (PAM) Instrumentation," was revised to add a new Function 25, "Containment Recirculation Sump Water Level." The new function provides an-alarm if the water level in the sump drops below an acceptable level.

Attachment 3 to AEP:NRC:8054-02 Page 310 TS Surveillance Requirement SR 3.5.2.7 was modified by changing the terms "trash racks and screens" to "strainers" to provide a more appropriate description of the sump configuration after the installation of a pocket-type strainer assembly.These TS changes have been implemented for Unit 2. In accordance with Reference 14, the TS changes will be implemented for Unit 1 following the Spring 2008 Unit 1 RFO. Submittal and NRC-approval of this amendment request did not require a 10 CFR 50.59 evaluation.

Licensinq Basis Changes Associated with Mechanistic Evaluation I&M intends to change the licensing basis to reflect the mechanistic evaluation of the effect of post accident debris on the ECCS and CTS recirculation function as described in this letter.I&M intends to implement this licensing basis change by the end of May 2008, which is in accordance with the extension approved by Reference

16. The associated 10 CFR 50.59 evaluation will be completed as necessary to support the implementation date.

Attachment 3 to AEP:NRC:8054-02 Page 311 NRC Information Item 3- Conclusions As described in the responses to Information Items 3.a through 3.p, I&M has completed significant actions to resolve the GL 2004-02 concerns.

As also described in .those responses, the remaining actions will be completed in accordance with the NRC-approved extension (References 13 and 16). The following provides discussion on I&M's use of the alternate evaluation methodology addressed in Chapter 6 of the GR and SER, and provides a summary of the conservatisms and margins inherent in I&M's resolution of the GL 2004-02 concerns.Alternate Evaluation Methodology As described in the responses to Information Items 3.f and 3.o, I&M performed testing for both a DEGB and a DGBS. The purpose of performing testing for the two different break sizes was to support use of the alternate evaluation provisions of Chapter 6 of the GR and SER. The testing determined the overall system head loss for the DEGB to be approximately 0.13 ft H 2 0 less than the allowable strainer head loss of 2.8 ft H 2 0. As was described in References 11, 12, and 14, the strategy for mitigating an excessively high head loss would be to reduce flow through the strainers.

In accordance with EOPs, operators would accomplish this by securing a CTS pump, and if necessary, securing an RHR pump. Based on the testing results, a reduction in flow equivalent to securing a CTS pump would result in a decrease in head loss across the strainers of approximately 38% (3.f.4, Figure 3f4-21 and 3.g.7). This would provide approximately 1.14 ft H 2 0 margin to the established vortex limit of 601 ft 6 in.As described in the response to Information Item 3.g.7, the assumed single failure for containment minimum sump water inventory is one of the two CEQ fans. A single failure of a CEQ fan is limiting for minimum containment minimum sump water inventory because it would result in less flow through the ice bed, which would result in less ice melt. A single failure of a CEQ fan is also, limiting with respect to strainer head loss. If the single failure component was one of the operating ECCS or CTS pumps rather than one of the CEQ fans, the reduction in head loss that was described in the previous paragraph would result. The limiting single failure for CNP, as described in the UFSAR (Section 14.3.1.2), is the loss of an entire train of ECCS and CTS. With only a single train operating following a DEGB LOCA, the head loss across the strainers would be approximately 66% less than the full flow head loss. A further reduction in flow by the operators would not be required since strainer head loss would be well below the allowable head loss.The CNP licensing basis for single failure criteria (UFSAR Sections 1.4.7 -Criterion 41, 6.2.1,*6.2.3, Table 6.2-6, and Table 6.2-7) requires assumption of an active failure during the injection phase, or an active or passive failure during the recirculation phase. In the unlikely event that.the operating pump that corresponds to the pump that was stopped to reduce head loss failed, the pump that had been secured could be restarted to restore the function.

Since the CNP licensing basis does not require assumption of multiple failures, a failure of an operating pump.following a failure of a CEQ fan would be considered to be a beyond design basis condition.

If strainer head loss exceeded the allowable head loss, indicator ights and an audible annunciator would actuate in the control room. The operators would respond to the condition by securing a CTS pump, as described above. Since the predicted maximum head loss is slightly Attachment 3 to AEP:NRC:8054-02 Page 312 less than the maximum allowable head'loss, and will occur several hours following the event, as described in the response to Information Item 3.f.4, this condition will develop slowly. This will provide the operators with a significant quantity of time to respond to the condition.

As described in the response to Information Item 3.f.3, the established vortex limit was conservatively determined assuming the potential vortex formation would be in the same chamber of the recirculation sump as the pump suction pipes. The vortex elevation determined, 601 ft 6 in, implies that the vortex would form in the vent pipe in the rear chamber of the recirculation sump. Since there is no flow through the vent pipe, the potential for a vortex to form is significantly reduced. As described in Reference 31, the maximum vortex that did form in the front section of the scaled recirculation sump test configuration did not introduce air bubbles into the flow stream.Given these analysis and testing results, it is reasonable to assume that the water level inside the recirculation sump would have to drop to a substantially lower level to result in significant air entrainment to the suctions of the RHR and CTS pumps. Based on the limited potential for development of significant air entrainment, and the slowly developing head loss, it is reasonable to assume that the operators would have greater than thirty -minutes to recognize and take action to reduce head loss across the recirculation sump strainers.

In summary, the proposed mitigation strategy of securing a CTS pump, and if necessary, an RHR pump, to ensure continued core and containment cooling following a DEGB LOCA with an excessive recirculation sump strainer head loss, is considered to be in accordance with the requirements of the GR and SER.Conservatisms and Margins A description of the conservatisms and margins for each aspect of the resolution of GL 2004-02 are provided below. Additional discussions of these conservatisms and margins are provided in the responses to the indicated information items.Debris Generation (Information Item 3.b)* I&M conservatively assumed that 100% of all unqualified coatings have failed by the initiation of recirculation following a LOCA. This is conservative with respect to the results of EPRI testing of unqualified coatings documented in Reference 92, in which none of the coatings tested failed completely.

I&M conservatively calculated the total quantity of unqualified coatings (Reference 67), by assuming greater coating thicknesses and surface areas than likely exist in containment.

The assumed quantity could likely be reduced through extensive surveys and testing.* I&M assumed a conservative value for the quantity of debris generated and the associated ZOI with respect to the destructive test results documented in Reference 30 for the associated materials.

Attachment 3 to AEP:NRC:8054-02 Page 313 I l&M conservatively applied a ZOI of 5D for qualified coatings within a ZOI in lieu of 4D recommended by WCAP-1 6568-P (Reference 87).Latent Debris (Information Item 3.d)* I&M conservatively assumed a bounding quantity of latent debris in containment of 200 lbs. This provided margins of at least 20 lbs for Unit 1 and at least 60 lbs for Unit 2 with respect to the quantity determined by sampling during walkdowns (References 33, 34, and 35).* I&M conservatively assumed 15% of the latent debris to be fiber. This is conservative because there is very little fiber insulation in the CNP containments, and none in an area that would be subjected to jet impingement from an event that would lead to recirculation.

Very little of the debris collected during walkdowns (References 33, 34, and 35) was identified as fibrous or fiber-like.

I&M conservatively assumed the available sacrificial strainer areas to be 76 ft 2 for the main strainer and 83 ft 2 for the remote. This provides a margin of approximately 50 ft 2 for the main strainer and 54 ft 2 for the remote strainer based on the quantity of material that was determined to be at the strainers, i.e., approximately 26 ft 2 and 29 ft 2 , respectively.

Debris Transport (Information Item 3.e)I&M conservatively assumed that:* Unqualified labels and PVC jacketing would be transported the same as readily transportable fines.* Debris in the sump pool would not transport to the reactor cavity while it was filling through the nuclear instrumentation positioning device penetrations.

All debris in, or blown into, the ice condenser would wash back into the containment pool.* There would be no debris hold-up on containment equipment or structural elements as a result of transport from the initial blowdown, or during washdown.* Water falling from the break would enter the pool without impacting any interferences, maximizing the pool turbulence and providing for greater debris transport potential.

100% of the debris sources in upper containment would fail and be transported to the area of the refueling canal drains..0 Debris that had not been transported to the annulus or into the main strainer would be evenly distributed within the loop compartment, increasing the total quantity of material available for transport during recirculation.

This was conservative because a significant quantity of the debris in the loop compartment would actually be at, or near, the overflow wall DI and main strainer at the conclusion of pool fill, therefore reducing the quantity of debris available for transport to the main strainer.* Additionally, a significant number of the debris sources were conservatively assigned transport fractions for the main and remote strainer, that when added together, resulted in a greater quantity of debris available for transport than would exist in the active containment pool.

Attachment 3 to AEP:NRC:8054-02 Page 314 Head Loss and Vortexing (Information Item 3.f)" The head loss results from strainer testing were conservatively normalized to 200C (68°F), which is below the expected minimum sump temperature of 800 to 1000 F.0 A multiplier of 1.5 was conservatively applied to the calculated system head loss for the DEGB and DGBS that was based on the large scale strainer test results. This multiplier provided a margin of 0.524 ft H 2 0 for system head loss for the DEGB, and a margin of 0.41 ft H 2 0 for the DGBS." The head loss analysis conservatively assumed the water level in containment was at its minimum water level at the time of maximum head loss.* The vortex analysis conservatively evaluated the potential for formation of a vortex assuming the water surface being evaluated was in the same chamber of the sump as the suction piping for the recirculation sump, even though the water surface would actually be in the front chamber of the recirculation sump (flowing area) and the vent pipe (non-flowing area).* Conservatively high flow rates were assumed for the ECCS and CTS while on recirculation.

A reasonably assumed 10% reduction in flow would result in an approximate 15% reduction in head loss.The containment water level analysis that established the minimum water level for containment included several conservatisms." The assumed mass and energy release from the RCS summed the contribution of water and steam flows leaving the RCS and assumed a thermodynamic equilibrium for this mixture. This maximized the water enthalpy and minimized the steam released to the containment atmosphere.

The assumed actuation setpoint for CTS was biased low such that CTS would provide a greater contribution to cooling the containment atmosphere.

The assumed CEQ fan flow was biased low to minimize flow through the ice condenser.

CTS was assumed to remain in service until a low biased reset point was reached.* The volumes of the annulus and loop compartment were modeled without displacement from internal structures.

Including a conservatively low volume for this displacement would provide an additional 2.2 in to the minimum water level." Input parameters were conservatively assumed to be at a value that would minimize ice melt.* Assumed hold-up volumes were conservatively biased high to minimize water available for the containment sump pool.NPSH (Information Item 3.g)The most conservative assumption used for determination of NPSH margin for the pumps that take suction on the recirculation sump was the use of 190OF water temperature, even though this temperature would exist for only a short duration at the beginning of recirculation.

However, since CNP is air entrainment limited and not NPSH limited, the conservatisms associated with determination of NPSH provide little margin in sump strainer head loss considerations.

Attachment 3 to AEP:NRC:8054-02 Pg 1 Page 315 Downstream Effects -Components and Systems (Information Item 3.g)The completed portion of this evaluation is the blockage evaluation of the components in the recirculation flow path, not including the pumps or reactor vessel and reactor core. In this evaluation, it was conservatively assumed that the size of the openings in the strainer was 33% larger than the size of the actual maximum strainer opening.Chemical Effects (information Item 3.o)" A bump-up factor of 1.7 was applied to the results of the chemical effects testing rather than the determined maximum increase of 1.53.* The test specification for the DGBS test conservatively used the values for chemical addition that were determined for the DEGB test. This resulted in the addition of non-aluminum chemicals of nearly three times the 100% value.* The pH values used for determination of the chemical precipitates was conservatively biased higher than the values expected in the post accident containment pool.* In the analysis to determine the amount of precipitate formed by the reaction between aluminum in containment and CTS spray, it was assumed that 100% of the RCP motor air cooler aluminum fins were subjected to the spray. However, due to the configuration of the fins and the primarily vertical direction of the spray flow, it is unlikely that the spray would reach all fins in the coolers. It is likely that 30% or more of the fins would not be subjected to the spray.

ML080770396

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