L-MT-13-081, Maximum Extended Load Line Limit Analysis Plus License Amendment Request - Request for Additional Information Responses

Maximum Extended Load Line Limit Analysis Plus License Amendment Request - Request for Additional Information Responses

ML13246A080
Person / Time
Site:	Monticello
Issue date:	08/14/2013
From:	Schimmel M Northern States Power Co, Xcel Energy
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
L-MT-13-081, TAC ME3145
Download: ML13246A080 (39)

Text

ENCLOSURES 1, 3 AND 5 CONTAIN PROPRIETARY INFORMATION WITHHOLD FROM PUBLIC DISCLOSURE IN ACCORDANCE WITH 10 CFR 2.390 9@ XoeIEnergy Monticello Nuclear Generating Plant 2807 W County Rd 75 Monticello, MN 55362 August 14, 2013 L-MT-13-081 10 CFR 50.90 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Monticello Nuclear Generating Plant Docket 50-263 Renewed License No. DPR-22

Subject:

Maximum Extended Load Line Limit Analysis Plus License Amendment Request - Request for Additional Information Responses (TAC ME3145)

References:

1) Letter from T J O'Connor (NSPM), to Document Control Desk (NRC),

"License Amendment Request: Maximum Extended Load Line Limit Analysis Plus," L-MT-10-003, dated January 21, 2010. (ADAMS Accession No. ML100280558)

2) Email from T Beltz (NRC) to J Fields (NSPM), "Monticello -

MELLLA+ Review - Draft Requests for Additional Information (TAC No. ME3145).docx," dated April 9, 2013.

3) Letter from M A Schimmel (NSPM) to Document Control Desk (NRC), "Maximum Extended Load Line Limit Analysis Plus License Amendment Request - Request for Additional Information Responses (TAC ME3145)," L-MT-13-070, dated July 31, 2013.

4) Letter from M A Schimmel (NSPM) to Document Control Desk (NRC), "Maximum Extended Load Line Limit Analysis Plus License Amendment Request - Request for Additional Information Responses for TRACE/TRACG Differences (TAC ME3145),"

L-MT-12-108, dated December 21, 2012. (ADAMS Accession No. MLI13002A261)

In Reference 1, Northern States Power Company, a Minnesota corporation (NSPM),

doing business as Xcel Energy, requested approval of an amendment to the Monticello Nuclear Generating Plant (MNGP) Renewed Operating License (OL) and Technical

Document Control Desk Page 2 Specifications (TS). The proposed change would allow operation in the expanded Maximum Extended Load Line Limit Analysis Plus (MELLLA+) domain.

In Reference 2 the NRC provided Requests for Additional Information (RAIs) pertaining to the quench front velocity in the TRACG computer model.

In Reference 3 NSPM provided a response to a portion of the NRC RAIs in Reference 2. The purpose of this letter is to provide a response to the remaining RAIs. provides a report from General Electric - Hitachi (GEH) letter, GE-MNGP-AEP-3299R1, "GEH Response to MELLLA+ RAIs 1, 2 and 3.h." contains proprietary information. provides a non-proprietary copy of the Enclosure 1 RAI responses. The non-proprietary copy of the RAI responses is being provided based on the NRC's expectation that the submitter of the proprietary information should provide, if possible, a non-proprietary version of the document with brackets showing where the proprietary information has been deleted. provides a report from GEH letter, GE-MNGP-AEP-3299R1, "GEH Corrected Responses to MELLLA+ Round 1 RAIs 1, 3, 4 and 5." Enclosure 3 provides corrected responses to previously provided RAI responses provided in Reference 4.

This enclosure contains proprietary information. provides a non-proprietary copy of the Enclosure 3 RAI responses. provides a compact disc (CD), entitled "RAI-4 TRACG Inputs" containing data requested by the NRC to support responses to RAI 4 in Enclosure 3. The entire contents of the CD are considered proprietary information. As such this information is also covered by the affidavit provided by GEH in Enclosure 6. contains an affidavit executed to support withholding Enclosures 1, 3 and 5 from public disclosure. Information in Enclosures 1, 3 and 5 contain proprietary information as defined by 10 CFR 2.390. The affidavit sets forth the basis on which the information may be withheld from public disclosure by the NRC and addresses with specificity the considerations listed in 10 CFR 2.390(b)(4). Accordingly, NSPM respectfully requests that the proprietary information in Enclosures 1, 3 and 5 be withheld from public disclosure in accordance with 10 CFR 2.390(a)4, as authorized by 10 CFR 9.17(a)4.

Correspondence with respect to the copyright or proprietary aspects of GEH information or the supporting GEH affidavit in Enclosure 6 should be addressed to James F Harrison, Vice President, Regulatory Affairs, GE-Hitachi Nuclear Energy Americas LLC, 3901 Castle Hayne Road, Wilmington, NC 28401.

Document Control Desk Page 3 The supplemental information provided herein does not change the conclusions of the No Significant Hazards Consideration and the Environmental Consideration evaluations provided in Reference 1 for the MELLLA+ license amendment request.

In accordance with 10 CFR 50.91(b), a copy of this application supplement, without enclosures is being provided to the designated Minnesota Official.

Summary of Commitments This letter makes no new commitments or revisions to existing commitments.

I declare under penalty of perjury that the foregoing is true and correct.

Executed on: August14, 2013 Mark A. Schimmel Site Vice-President Monticello Nuclear Generating Plant Northern States Power Company-Minnesota Enclosures (6) cc: Regional Administrator, Region III, USNRC (w/o enclosures)

Project Manager, Monticello Nuclear Generating Plant, USNRC Resident Inspector, Monticello Nuclear Generating Plant, USNRC (w/o enclosures)

Minnesota Department of Commerce (w/o enclosures)

L-MT-13-081 ENCLOSURE 2 GE-MNGP-AEP-3299R1, ENCLOSURE 2 GEH RESPONSE TO MELLLA+ RAIS 1, 2 AND 3.H NON-PROPRIETARY 16 pages follow

ENCLOSURE 2 GE-MNGP-AEP-3299R1 GEH Response to MELLLA+ RAIs 1, 2 and 3.h Non-proprietary Information - Class I (Public)

NON-PROPRIETARY NOTICE This is a non-proprietary version of the Enclosure 1 of GE-MNGP-AEP-3299R1 which has the proprietary information removed. Portions of the document that have been removed are indicated by an open and closed bracket as shown here (( R

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Page 2 of 16

RAI 1

Data Matching

a. Please validate the performance of the GEH quench model using separate effects tests with conditions as close to those expected in an A TWS as possible. Tests with high reflood (coolant) velocities that help examine quenchfront propagationover a range ofpressure are particularly important.

Tests that couldfulfill this assessment include:

i. THTF Transient Blowdown Tests (see NUREG/CR-2525) such as 3.03.6AR, 3.06.6B, and 3.08.6C ii. FLECHT Group I Tests with reflood rates greaterthan 6 in/sec such as Tests 0303, 0408, 0509, 0913, 5019 (10 in/sec) and 4 (17.9 in/see) iii. FLECHT-SEASET Tests with reflood rates greaterthan 6 in/sec (see NUREG/CR-1532) such as 31701 (6.1 in/sec) and the initialportion of 33338 (14 in/sec)

GEH Response To further assess the TRACG quench model, selected LOCA Integral System Tests (ISTs) were evaluated with and without the quench model activated. Cases were selected for tests performed at facilities that had previously been evaluated in the TRACG Qualification LTR (Reference 1-1). Selected cases are those where the test data temperature traces indicate a quench. The tests evaluated in this response are: Thermal Hydraulic Test Facility (THTF) transient blow down tests 3.03.6AR, 3.06.6B, and 3.08.6C (References 1-5, 1-6); Two-Loop Test Apparatus (TLTA) test 6423 (Reference 1-7); and ROSA-11 tests 912 (Reference 1-8) and 926 (Reference 1-9). All tests except for THTF test 3.03.6AR were previously evaluated in Reference 1-1. Relevant details for the re-evaluations presented here are summarized in Table 1-1. All the TRACG calculations were executed using the Shumway Tmin correlation with the void term disabled and the cladding material appropriate for the test as indicated in Table 1-1.

The temperatures presented in Table 1-1 show that generally the TRACG calculated maximum temperature ((

)) for these LOCA-like cases the maximum temperature is reached and begins to decrease based on precursory steam cooling that exists prior to when the quench occurs. The LOCA scenarios are unlike the ATWSI scenario because for LOCA the cladding has a longer heatup time at a much lower heat flux in a fluid environment where there is very little liquid water. The ATWSI scenario with power and flow oscillations near the operating reactor pressure is much better represented by the Halden test cases where the reactor remains at power, flow is reduced to produce the boiling transition and is later increased after the dryout to simulate the flow surge and cause return to nucleate

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Page 3 of 16 boiling. For comparison of TRACG calculations to the Halden test data please see revision 1 of the response for RAI 3 (Enclosure 4).

For an ATWSI scenario, a representative calculated quench velocity is in the range of ((

)) m/s as shown in Figure 3.h-I of the response to RAI 3.h. Table 1-1 shows that for THTF tests 3.03.6AR and 3.06.6B the calculated quench velocity over the last second before the quench at the thermocouple (T/C) elevations are respectively 0.43 and 0.32 m/s (16.9 and 12.6 inch/s) similar to the FLECHT and FLECHT-SEASET quench velocities cited in the NRC RAI. The ATWSI power/flow oscillations occur near the normal operating pressure of a BWR whereas for the LOCA-like test cases the quench occurs for a range of lower pressures as indicated in Table 1-1.

Table 1-1: Test Data and TRACG Comparison Summary for LOCA-like Scenarios Maximum Temperature' (K) Velocity3 Quench(i)Pesr Estimated (m/s) Pressure Clad TRACG Last (MPa) at Material Test Quench Quench ation along Second Time of Data Model Model ()Before Quench OFF ON Quench Stainless THTF 3.03.6AR Steeless 9949 3.6 0.08 0.43 5.6 Stainles THTF 3.06.6B Stainless 1135 3.6 0.11 0.32 5.8 Steel THTF 3.08.6C Stainless 1204 2.4 0.10 0.07 6.6 Steel TLTA 6423 Inconel 802 2.0 0.01 0.05 0.60 ROSA-Ill 912 Inconel 839 0.94, 0.02 0.15 1.4 1.11 ROSA-Ill 926 Inconel 784 )) 0.94 0.01 0.07 0.40

'The M-airimum Temperature corresponds to the peak value for the specific rod and location that is being compared.

2 The elevation indicates where the maximum temperature was taken for the test data and TRACG. The maximum temperature from the node plotted for the respective test and elevation is used. For ROSA-Ill 912, the TRACG calculated temperature peak occurs for the node at 1.1 lm so it is the temperature trace at that elevation that is tabulated and plotted.

3 The Quench Velocity was calculated by dividing the distance the quench front traveled by the elapsed time to travel that distance based on the TRACG indicated position of the quench front with time.

Calculated TRACG temperature traces with time are compared to the test data in Figures 1-1 through 1-6. The red curves labeled "TRACG Nominal" in these figures are from calculations where the quench model was turned OFF. The blue curves labeled "TRACG Quench" are with the quench model turned ON. The green and turquoise curves show the measured data. For these LOCA scenarios the quench front movement is limited by the rate of liquid water

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Page 4 of 16 addition rather than the inability to return to nucleate boiling. Steam produced lower in the bundle serves to reduce measured temperatures at the higher elevations before the quench front propagates to the maximum measured temperature elevation. It is this precursory cooling process that is the reason both the measured and calculated temperature traces are trending downward even before quenching occurs. Quench is suggested at the shoulder in the measured temperature trace where the temperature suddenly drops.

It is not always possible from the measured temperature traces to distinguish a temperature drop due to quenching and a drop due to an improvement in the heat transfer mode that results when the surface temperature is reduced below the minimum stable film temperature (Tmin).

The need to make this distinction is not essential because the TRACG quench and Trin models work together. The Tmin model defines the maximum surface temperature for which return to nucleate boiling can occur if there is sufficient liquid. When the surface temperature ahead of the quench front is above Tmin, the quench model has a higher relative importance because it provides for heat removal via axial conduction to liquid near the saturation temperature that exists below the quench front. On the other hand, if the surface temperature decreases below Train above the quench front then a higher heat transfer coefficient is calculated above the quench front and the axial temperature profile and thus the quench heat removal mechanism is decreased.

The TRACG Quench calculations presented in Figures 1-1 through 1-6 demonstrate that the TRACG quench and Tmin models are working well together in matching the quench temperaturedata. For example, consider the results in Figure 1-2 for THTF test 3.06.6B. For pressures between 5 and 6 MPa the Shumway correlation predicts a T,*, value of about 770 K for stainless steel for low flows and no void enhancement. Graphically it can be seen For comparison with the TRACG calculations and the test data, the TRACE calculated results are depicted by the purple curves in Figures 1-1, 1-2, and 1-3. The Groeneveld-Stewart Tmran correlation (derived from Inconel data) is used in TRACE to predict a Tmin value around 685 K at 5 MPa. This value is about 90 K lower than the Shumway prediction for stainless steel at 5 MPa. The impact of the lower value for Tmi,, is most apparent in the purple curves on the left side of Figure 1-2 and the right side of Figure 1-3. Primarily because of the lower value for Tmin, TRACE predicts a quench temperature that is lower than the data by at least 50 K.

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Page 5 of 16 References 1-1 GE Nuclear Energy, "TRACG Qualification Licensing Topical Report," NEDE-32177P Revision 3, August 2007.

1-2 Not used 1-3 Not used 1-4 Not used 1-5 US Nuclear Regulatory Commission, "An Analysis of Transient Film Boiling of High-Pressure Water in a Rod Bundle," NUREG/CR-2469, March 1982.

1-6 TRACE V5.0 Assessment Manual, Appendix B: Separate Effects Tests, http://pbadupws.nrc.gov/docs/ML 1200/ML120060191 .pdf 1-7 BWR Large Break Simulation Tests - BWR Blowdown/Emergency Core Cooling Program, GEAP-24962, NUREG/CR-2229, March 1981.

1-8 Experiment Data of ROSA-III Integral Test Run 912, JAERI-M 82-010, January 1982.

1-9 ROSA-Ill 200% Double-ended Break Integral Test RUN 926, JAERI-M 84-008, February 1984.

References 1-2, 1-3, and 1-4 are retained here to enable alignment of the higher Reference numbers used in the figure legends.

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Page 6 of 16

((

Figure 1-1 Temperature Comparison for THTF Test 3.03.6AR

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Page 7 of 16

((

Figure 1-2 Temperature Comparison for THTF test 3.06.6B

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Page 8 of 16 Figure 1-3 Temperature Comparison for THTF Test 3.08.6C

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Page 9 of 16

[1 Figure 1-4 Temperature Comparison for TLTA[1-71 Test 6423

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Page 10 of 16 Figure 1-5 Temperature Comparison for ROSA-Ill test 91211-81

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Page 11 of 16 Figure 1-6 Temperature Comparison for ROSA-Ill Test 92611-9]

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Enclosure 2 Page 12 of 16 NRC RAI 2.a.

In response to RAI 3, sensitivity study resultsfor TRACG with and without the quench model are shown in Figure 3-12. When the quench model is not used, heatup begins at about 81 seconds into the runtime. When the quench model is used, heatup does not begin until about 84 seconds into the run time.

Please explain the difference in heatup initiationbetween the two scenarios.

• GEH Response After the main flow is shut off in Halden Test #12, there continues to be some flow through the channel. The high-power and low-flow conditions are such that the rod is very close to the critical heat flux. Very small changes in thermal or hydraulic conditions can lead to transition or film boiling. The Halden temperature result suggests this as indicated in the fluctuation in temperature.

The quench case heats up later because it benefits from the additional quench cooling. After the quench front completely drops below the thermocouple location, the cladding heats up.

With the revised TRACG04P code with the corrected quench model, there is also a difference in the heatup time, but in the revised response to RAI 3 (Enclosure 4), ((

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Page 13 of 16 RAI-2b:

Verify that the variable defined in 7TREF in the TRACG output deck is what is usedfor Tw+ in Equation (2-1) that describes the quench model. In addition,identify the location used to determine the "velocity upstream of the quenchfront" in Equation (2-5).

GEH Response:

The TTREF edit in the TRACG output file is:

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Page 14 of 16 RAI-3.h

3. DetailedCode Questions

h. The "Monticello Audit slides" show thatfor conditions typical ofATWS-1, the quenchfront velocity is calculatedto be (( )) using the correlation.In TRACG, the quench front velocity is limited to be less than (( )). In Figure5-5 (from the response to RAI 5), the quench front is moving at (( )) for the Shu'mway no void case and at about (( )) for the SS304 property case.

Please explain this result.

GEII Response Please note that Figure 5-5 referenced in the RAI is not included in the revised response to RAI 5 (Enclosure 4). The response to RAI 5 (Enclosure 4) was revised to correct an error in the TRACG quench model. In its place, Figure 3.h-1 is provided and shows the rod surface temperature for the hot rod node 17, the bottom elevation of node 17, the corresponding rod quench front elevation and velocity for the TRACG calculated bottom quench front (Vq). Vq is the velocity calculated using Equation 2-4 of Reference 3.h-1.

In the Monticello audit slides (Reference 3.h-2), the calculated velocity, Vq, of

(( )) is based on an assumed temperature of (( )) and the heat transfer coefficient for falling film quenching. Using a temperature of (( )) Vq is more consistent with the Vq value shown in Figure 3.h- 1 at the time the quench front enters node 17

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Page 15 of 16 1]

References:

3.h-I Response to Monticello Nuclear Generating Plant- Draft Request for Additional information re: MELLLA+ License Amendment Request Review (TAC No. ME3145) -

Revision 1, GE-MNGP-AEP-3223, December 14, 2012.

3.h-2 Presentations from the NRC Audit of Monticello MELLLA+ ATWS/I, October 24th and 25th, GE-MNGP-AEP-321, October 30, 2012.

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Page 16 of 16 Figure 3.h-1 Quench Movement

L-MT-13-081 ENCLOSURE 4 GE-MNGP-AEP-3299R1, ENCLOSURE 4 GEH CORRECTED RESPONSES TO MELLLA+ ROUND 1 RAIs 1, 3,4 AND 5 NON-PROPRIETARY 14 pages follow

ENCLOSURE 4 GE-MNGP-AEP-3299R1 GEH Corrected Responses to MELLLA+ Round 1 RAIs 1, 3, 4, and 5 Non-proprietary Information - Class I (Public)

NON-PROPRIETARY NOTICE This is a non-proprietary version of the Enclosure 3 of GE-MNGP-AEP-3299R1 which has the proprietary information removed. Portions of the document that have been removed are indicated by an open and closed bracket as shown here (( I].

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Page 2 of 14 NRC RAI 1 For a typical quenchfront calculatedby TRACGO4 for representativeATWSI [anticipatedtransients without scram with instability]conditions,provide the heat rate to the liquid and vapor state and the quench component of the heat rate. Compare with the measuredheat rate values published by Thompson in NED 1974, "On the Process of Rewetting a Hot Sulface by a FallingLiquid."

GEH Revised Response The requested plots are provided based on Halden Experiment 4 TRACG run from RAI 3 (See Figure 3-3). Figure 1-1 shows the heat rate to the liquid and vapor and the quench heat rate for heated Node 36 (Location of the upper temperature measurement). ((

The T. S. Thompson paper, listed in the RAI, evaluates the heat transfer at the quench front. Note that the paper used in this RAI (Reference 1-1) is the paper noted on the footnote on page one of the T. S.

Thompson paper listed in the RAI, as a better copy of the reference paper was available. Figures 13 and 14 show the heat flux in the vicinity of the interface (quench front) for variations in pressure and downstream temperature. This shows that the quench front is a "high-heat-flux zone" with heat flux as high as 30 times the liquid heat flux just 0.12 inches (0.3 cm) from the quench front.

The TRACG quench model predicts ((

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Page 3 of 14 II Figure 1-1 Quench Heat Rate References 1-1 T. S. Thompson, AECL-4516, "ON THE PROCESS OF REWETT[NG A HOT SURFACE BY A FALLING LIQUID FILM," Atomic Energy of Canada Limited, June 1973.

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Page 4 of 14 NRC RAI 3 Generate TRACG quench model inputsfor a number of Halden dr out experiments andprovide a comparison of the results to validate the quenchfiont velocity model at high power andpressures.

GEH Revised Response Since the original response to this RAI, there are 2 changes that were made to the code and model:

1. The TRACG04 quench model is corrected.

2. The Halden test reflood flow is updated.

In the original TRACG Halden test cases, the reflood flow was estimated based on figures from the Halden test report (Reference 3-1). However, these figures lacked sufficient detail to adequately determine actual reflood flowrates. Subsequently, additional information was provided from Halden that shows more accurate data that reflects higher reflood flowrates than previously estimated.

The final Halden experiments analyzed with TRACG in the original RAI response are repeated here.

All TRACG cases were performed with the modified Shumway (no void-term) Tmin correlation with zirconium (Zr) material properties unless otherwise indicated.

Experiment 3 The TRACG clad temperature result is shown in Figures 3-1. The results show good agreement in the quench.

Experiment 4 The TRACG clad temperature result is shown in Figures 3-2. The results show good agreement in the quench.

Several cases were performed to assess the effect of turning off the TRACG quench model and lowering the Tmin compared to the modified Shumway Tmin. Tmin is lowered by assuming Stainless Steel 304 (SS304) material properties in the modified Shumway correlation. Figure 3-3 shows the clad temperature results. The results show that the quench model is effective in reducing the clad temperature. ((

Experiment 1 Ic Experiment 11 involved a series of 6 dryout tests. Rather than attempt to model the series, only the dryout that resulted in the highest temperature is assessed. This portion of the test occurred between 900 and 1000 seconds and is called Test I Ic.

For Experiment 11, ((

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Page 5 of 14 The clad temperature result is shown in Figure 3-4. The results show that the TRACG quenching is reasonable compared to the test.

Experiment 12 For Experiment 12, ((

)) The clad temperature result is shown in Figure 3-5. The results show that the TRACG quenching occurs similar to the test.

Several cases were performed to assess the effect of turning off the quench model and lowering Tmin.

Tmin is lowered by assuming SS304 material properties in the modified Shumway correlation. ((

Figure 3-6 shows the clad temperature results. The results show that the quench model is effective in reducing the clad temperature and that quenching is crucial to adequately model the test.

In summary, the above TRACG comparison to the Halden experiments validates the TRACG quench model at ATWS with instability conditions.

Reference 3-1 HWR-552, "OECD Halden Reactor Project - The Third Dryout Fuel Behaviour Test Series in IFA-613." February 1998.

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Page 6 of 14 Figure 3-1. TRACG Clad Temperature Results Compared to Test 3 Figure 3-2. TRACG Clad Temperature Results Compared to Test 4

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Page 7 of 14 Figure 3-3. TRACG Clad Temperature Results Compared to Test 4 -

Effects of Quench Model and Tmin Model

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Page 8 of 14 Figure 3-4. TRACG Clad Temperature Results Compared to Test 11 1]

Figure 3-5 TRACG Clad Temperature Results Compared to Test 12

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Page 9 of 14 Figure 3-6. TRACG Clad Temperature Results Compared to Test 12 -

Effects of Quench Model and Tmin Model 11

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Page 10 of 14 NRC RAI 4 Provide the TRACG input decks for the Halden experiments including the digitized datafrom the experiments used to compare the results. In addition,pleaseprovide the TRACG outputfile and CEDAR file (in ascii ifpossible).

GEH Revised Response The following files are provided on the Enclosure 5 CD-ROM.

Case Steady-State Transient Input File Transient Output Transient Graphics File Basedeck File 03 ((

04 11 12 In addition, the file PCT Experiment.txt is provided that contains the measured clad temperatures extracted from the test report for the four experiments of interest.

The clad temperature is taken from 5 centimeters from the top of the heated portion of the rod. This corresponds to TRACG parameter RODT230136 for Cases 3 and 4 that use the fresh-fuel rod model and to RODT230138 for Cases 1I and 12 that use the irradiated rod model.

It is noted that the TRACG initial time corresponds to different experiment times:

• Experiment 3 test time of 15.0 seconds corresponds to a TRACG time of 0.0 seconds

• Experiment 4 test time of 30.0 seconds corresponds to a TRACG time of 0.0 seconds

• Experiment 1Ic test time of 930.0 seconds corresponds to a TRACG time of 930.0 seconds.

However, the TRACG input conditions prior this time differ. TRACG assumes steady conditions prior to this time.

• Experiment 12 test time of 40.0 seconds corresponds to a TRACG time of 40.0 seconds.

However, the TRACG input conditions prior this time differ. TRACG assumes steady conditions prior to this time.

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Enclosure 4 Page 11 of 14

RAI 5

Reproduce the ATWSI calculationsfor MNGP with and without applying the void and the Zr credit in the Shumway T,,i,, correlation using the latest version of the TRACG code.

Provide a comparison of results.

Provide a plot that shows the hot rod clad temperature on the same plot as the calculatedT,,i as function of time.

Provide a comparisonfor the variablesshown in Figs 9-12 through 9-14 of NEDC-33435P, Revision 1.

GEH Revised Response GEH identified an error in the TRACG04 code that affects the results previously provided in RAI 5.

The error is in the bottom reflood quench model and is described in RAI 3.g. Modifications were made to TRACG04 to correct the error. With the corrected bottom reflood quench model the bottom reflood quench is not as effective and potentially results in negative impact on the calculated Peak Cladding Temperature (PCT) for ATWSI scenarios. Note that there is no effect on the TRACG ATWS PCT results for the Main Steam Isolation Valve Closure PCT results presented in Table 9-4 and Figure 9-11 of Reference 5-1 because the quench model is not used in the calculations.

The Monticello ATWSI cases are rerun with the modified TRACG04 code. During these runs a few assumptions are changed to reduce the degree of conservatism in the analysis. The most significant conservatism was in the assumed time for manual action to lower water level following Turbine Trip with Full Bypass (TTWFB). The assumption used in the Monticello ATWSI TTWFB scenario was to initiate reactor water level reduction at 250 seconds (Reference 5-1, See section 9.3.3). This is significantly later that the expected operator action time. A value of 90 seconds is acceptable because this value is based on a time critical operator action that Monticello operators are required to demonstrate. As can be observed in the TTWFB results presented in Figures 9-12 through 9-14 of Reference 5-1 a water level reduction at 90 seconds would mitigate the ATWSI event before large oscillations develop and result in cladding heat-up at greater than 150 seconds into the event.

TRACG04 runs using the 90 second operator action time confirm that the event is mitigated before significant oscillations begin. Given this result, the two pump reactor Recirculation Pump Trip (RPT) event is limiting for ATWSI with respect to PCT. Another assumption that is changed is to increase the peaking of the hot channel hot rod power in TRACG to the fuel design Linear Heat Generation Rate (LHGR) limit; this results in a very large hot rod peaking factor. The analysis is performed with 5% margin to the limit at BOC and MOC. At EOC the fuel is CPR limited; therefore, the hot rod LHGR in TRACG is set to the peak core LHGR when the core CPR is within 5% of the limit. EOC is typically not limiting for ATWSI analysis. This assumption remains conservative and appropriate for use in the beyond design basis ATWSI analysis, as the core is designed with more than 5% margin to the thermal limits (typically 10 for LHGR). The MNGP MELLLA+ core design evaluation includes at least 10 % LHGR margin and for most of the cycle it is 15% or more.

GE-MNGP-AEP-3299R1 Non-Proprietary Information- Class I (Public)

Page 12 of 14 The discussion below is the revised response to RAI 5, which includes the results from the RPT event evaluation run with the modified TRACG04 bottom reflood quench model.

Three sensitivity cases are performed. Case 1, Shumway, is performed with the Shumway Minimum Stable Film Boiling Temperature (Tmin) correlation without modification. Case 2, Shumway -No Void, uses the Shumway Tmin correlation without the void dependence term applied (See Equation 19 of Reference 5-2). Case 3, Shumway - No Void, SS304 Properties, uses the Shumway Tmin correlation without the void dependence term and uses Stainless Steel 304 (SS304) material properties in the Shumway Beta Term (See Equation 10 and 19 in Reference 5-2). Use of the SS304 properties significantly lowers the Tmin value relative to using the Zr material properties, introducing a significant conservative bias in the Tmin correlation. The sensitivities are performed with the limiting RPT condition which is at BOC exposure and regional oscillation channel grouping.

The results of the RPT sensitivities are provided below. As can be seen the RPT scenario results in much lower temperatures than the TTWFB scenario presented in Reference 5-1 with the conservative water level reduction time assumption. Table 5-1 shows that ((

l1 Table 5-1 Train Sensitivity Results Original 2

I NEDC-33435P Shumway Shumway- No Void I

3 Shumway -No Void, SS304 Properties Figures 5-1 through 5-3 show the requested Tmin sensitivities with the same variables shown in Figures 9-12 through 9-14 of Reference 5-1. Figure 5-3 shows the peak cladding temperature and Tmin. The Figure shows that ((

GE-MNGP-AEP-3299RI Non-Proprietary Information- Class I (Public)

Page 13 of 14 Figure 5-1 Tmin Sensitivity Results - Core Power

((

Figure 5-2 Tmin Sensitivity Results - Hot Channel Power

GE-MNGP-AEP-3299R1 Non-Proprietary Information- Class I (Public)

Page 14 of 14 Figure 5-3 Tmin Sensitivity Results - PCT and Tm 1 in

References:

5-1 GE Hitachi Nuclear Energy, "Safety Analysis Report for Monticello Maximum Extended Load Line Limit Analysis Plus," NEDC-33435P, Revision 1, December 2009.

5-2 R. W, Shumway, EGG-RST-678 1, "TRAC-BWR HEAT TRANSFER: ASSESSMENT OF TMIN," January 1985.

L-MT-1 3-081 ENCLOSURE 6 GENERAL ELECTRIC - HITACHI AFFIDAVIT FOR WITHHOLDING PROPRIETARY INFORMATION 3 pages follow

GE-Hitachi Nuclear Energy Americas LLC AFFIDAVIT I, James F. Harrison, state as follows:

(1) I am the Vice President Fuel Licensing of GE-Hitachi Nuclear Energy Americas LLC (GEH), and have been delegated the function of reviewing the information described in paragraph (2) which is sought to be withheld, and have been authorized to apply for its withholding.

(2) The information sought to be withheld is contained in Enclosures 1, 3, and 5 of GEH letter, GE-MNGP-AEP-3299R1, "GEH Response to MELLLA Plus Requests for Additional Information," dated August 12, 2013. The GEH proprietary information in Enclosure 1, which is entitled "GEH Response to MELLLA+ RAIs 1, 2 and 3.h," and Enclosure 3 which is entitled "GEH Corrected Responses to MELLLA+ Round 1 RAIs 1, 3, 4, and 5," is identified by a dark red dotted underline inside double square brackets. ((Ti.s..sentence.isan.

example. (3 )). The content of Enclosure 5, which is a CD-ROM entitled "RAI-4 Information", is proprietary in its entirety. The label on the CD-ROM carries the notation "GEH Proprietary Information - Class III (Confidential){3}." In each case, the superscript notation ý3) refers to Paragraph (3) of this affidavit that provides the basis for the proprietary determination.

(3) In making this application for withholding of proprietary information of which it is the owner or licensee, GEH relies upon the exemption from disclosure set forth in the Freedom of Information Act (FOIA), 5 U.S.C. Sec. 552(b)(4), and the Trade Secrets Act, 18 U.S.C.

Sec. 1905, and NRC regulations 10 CFR 9.17(a)(4), and 2.390(a)(4) for trade secrets (Exemption 4). The material for which exemption from disclosure is here sought also qualifies under the narrower definition of trade secret, within the meanings assigned to those terms for purposes of FOIA Exemption 4 in, respectively, Critical Mass Energy Project v. Nuclear Regulatory Commission, 975 F.2.d 871 (D.C. Cir. 1992), and Public Citizen Health Research Group v. FDA, 704 F.2.d 1280 (D.C. Cir. 1983).

(4) The information sought to be withheld is considered to be proprietary for the reasons set forth in paragraphs (4)a. and (4)b. Some examples of categories of information that fit into the definition of proprietary information are:

a. Information that discloses a process, method, or apparatus, including supporting data and analyses, where prevention of its use by GEH's competitors without license from GEH constitutes a competitive economic advantage over GEH or other companies.

b. Information that, if used by a competitor, would reduce their expenditure of resources or improve their competitive position in the design, manufacture, shipment, installation, assurance of quality, or licensing of a similar product.

c. Information that reveals aspects of past, present, or future GEH customer-funded development plans and programs, that may include potential products of GEH.

Affidavit for GE-MNGP-AEP-3299RP Pagel1 of 3

GE-Hitachi Nuclear Energy Americas LLC

d. Information that discloses trade secret or potentially patentable subject matter for which it may be desirable to obtain patent protection.

(5) To address 10 CFR 2.390(b)(4), the information sought to be withheld is being submitted to the NRC in confidence. The information is of a sort customarily held in confidence by GEH, and is in fact so held. The information sought to be withheld has, to the best of my knowledge and belief, consistently been held in confidence by GEH, not been disclosed publicly, and not been made available in public sources. All disclosures to third parties, including any required transmittals to the NRC, have been made, or must be made, pursuant to regulatory provisions or proprietary or confidentiality agreements that provide for maintaining the information in confidence. The initial designation of this information as proprietary information, and the subsequent steps taken to prevent its unauthorized disclosure are as set forth in the following paragraphs (6) and (7).

(6) Initial approval of proprietary treatment of a document is made by the manager of the originating component, who is the person most likely to be acquainted with the value and sensitivity of the information in relation to industry knowledge, or who is the person most likely to be subject to the terms under which it was licensed to GEH. Access to such documents within GEH is limited to a "need to know" basis.

(7) The procedure for approval of external release of such a document typically requires review by the staff manager, project manager, principal scientist, or other equivalent authority for technical content, competitive effect, and determination of the accuracy of the proprietary designation. Disclosures outside GEH are limited to regulatory bodies, customers, and potential customers, and their agents, suppliers, and licensees, and others with a legitimate need for the information, and then only in accordance with appropriate regulatory provisions or proprietary or confidentiality agreements.

(8) The information identified in paragraph (2) above is classified as proprietary because it contains results of an analysis performed by GEH to support the Monticello Maximum Extended Load Line Limit Analysis Plus (MELLLA+) license application. This analysis is part of the GEH MELLLA+ methodology. Development of the MELLLA+ methodology and the supporting analysis techniques and information, and their application to the design, modification, and processes were achieved at a significant cost to GEH.

The development of the evaluation methodology along with the interpretation and application of the analytical results is derived from the extensive experience database that constitutes a major GEH asset.

(9) Public disclosure of the information sought to be withheld is likely to cause substantial harm to GEH's competitive position and foreclose or reduce the availability of profit-making opportunities. The information is part of GEH's comprehensive BWR safety and technology base, and its commercial value extends beyond the original development cost.

The value of the technology base goes beyond the extensive physical database and Affidavit for GE-MNGP-AEP-3299RI Page 2 of 3

GE-Hitachi Nuclear Energy Americas LLC analytical methodology and includes development of the expertise to determine and apply the appropriate evaluation process. In addition, the technology base includes the value derived from providing analyses done with NRC-approved methods.

The research, development, engineering, analytical and NRC review costs comprise a substantial investment of time and money by GEH. The precise value of the expertise to devise an evaluation process and apply the correct analytical methodology is difficult to quantify, but it clearly is substantial. GEH's competitive advantage will be lost if its competitors are able to use the results of the GEH experience to normalize or verify their own process or if they are able to claim an equivalent understanding by demonstrating that they can arrive at the same or similar conclusions.

The value of this information to GEH would be lost if the information were disclosed to the public. Making such information available to competitors without their having been required to undertake a similar expenditure of resources would unfairly provide competitors with a windfall, and deprive GEH of the opportunity to exercise its competitive advantage to seek an adequate return on its large investment in developing and obtaining these very valuable analytical tools.

I declare under penalty of perjury that the foregoing affidavit and the matters stated therein are true and correct to the best of my knowledge, information, and belief.

Executed on this 1 2 th day of August, 2013.

James F. Harrison Vice President Fuel Licensing GE-Hitachi Nuclear Energy Americas LLC 3901 Castle Hayne Rd Wilmington, NC 28401 james.harrison@ge.com Affidavit for GE-MNGP-AEP-3299R1 Page 3 of 3