ML14342A229

License Amendment Request - Safety Limit Minimum Critical Power Ratio Change

ML14342A229
Person / Time
Site:	Peach Bottom
Issue date:	12/05/2014
From:	Jim Barstow Exelon Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
Download: ML14342A229 (43)

Text

xelon Generation@

PROPRIETARY INFORMATION -WITHHOLD UNDER 10 CFR 2.390 10 CFR 50.90 10 CFR 2.390 December 5, 2014 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555-0001 Peach Bottom Atomic Power Station, Unit 2 Renewed Facility Operating License No. DPR-44 NRC Docket No. 50-277

Subject:

License Amendment Request - Safety Limit Minimum Critical Power Ratio Change

Reference:

1. Exelon letter to the NRC, "License Amendment Request - Maximum Extended Load Line Limit Analysis Plus," dated September 4, 2014 (ADAMS Accession No. ML14247A503)

2. GE Hitachi Nuclear Energy, "General Electric Boiling Water Reactor Maximum Extended Load Line Limit Analysis Plus," NEDC-33006P-A, Revision 3, June 2009.

In accordance with 10 CFR 50.90, Exelon Generation Company, LLC (Exelon) requests a change to the Technical Specifications (TS) Section 2.1.1 ("Reactor Core SLs") for the Peach Bottom Atomic Power Station (PBAPS) Unit 2. Specifically, this change incorporates revised Safety Limit Minimum Critical Power Ratios (SLMCPRs) due to the cycle specific analysis performed by Global Nuclear Fuel for Peach Bottom Atomic Power Station (PBAPS) Unit 2 Cycle 21. The re-analysis was performed to accommodate operation in the Maximum Extended Load Line Limit Analysis Plus (MELLLA+) operating domain as discussed in Reference 1.

The proposed changes have been reviewed by the PBAPS Station Plant Operations Review Committee, and approved by the Nuclear Safety Review Board in accordance with the requirements of the Exelon Quality Assurance Program.

Exelon requests approval of this proposed LAR by September 9, 2015, with an implementation period to coincide with the PBAPS Unit 2 implementation of the MELLLA+

LAR (Reference 1).

There are no commitments contained within this letter. contains the evaluation of the proposed changes. Attachments 2 and 3 provide the marked up TS page and the retyped TS page, respectively.

Attachment 4 contains Proprietary Information.

When separated from Attachment 4, this document is decontrolled.

U.S. Nuclear Regulatory Commission License Amendment Request Safety Limit Minimum Critical Power Ratio Change December 5, 2014 Page 2 (letter from C. F. Lamb (Global Nuclear Fuel) to J. Tusar (Exelon), dated May 12, 2014) specifies the new SLMCPRs for PBAPS Unit 2 Cycle 21 for MELLLA+ conditions. contains information proprietary to Global Nuclear Fuel. Global Nuclear Fuel requests that the document be withheld from public disclosure in accordance with 10 CFR 2.390. Attachment 5 contains a non-proprietary version of the Global Nuclear Fuel document. An affidavit supporting this request is also contained in Attachment 4. contains the power/flow map for PBAPS Unit 2 Cycle 21 that shows both the current MELLLA and the proposed MELLLA+ operating domains.

In accordance with 10 CFR 50.91, Exelon is notifying the Commonwealth of Pennsylvania of this application for license amendment by transmitting a copy of this letter and its attachments to the designated State Official.

Should you have any questions concerning this letter, please contact David Neff at (610) 765-5631.

I declare under penalty of perjury that the foregoing is true and correct. Executed on the 5th day of December 2014.

Respectfully, ~--

Jame~~

Director, Licensing & Regulatory Affairs Exelon Generation Company, LLC Attachments: 1. Evaluation of Proposed Changes

2. Markup of Technical Specifications Page

3. Retyped Technical Specifications Page

4. Proprietary Version of Global Nuclear Fuel Report

5. Non-Proprietary Version of Global Nuclear Fuel Report

6. Power/Flow Map for Cycle 21 with MELLLA+ Operating Domain cc: USNRC Region I, Regional Administrator w/attachments USNRC Senior Resident Inspector, PBAPS w/attachments USNRC Project Manager, PBAPS w/attachments R.R. Janati, Commonwealth of Pennsylvania w/o proprietary attachment S. T. Gray, State of Maryland w/o proprietary attachment

ATTACHMENT 1 Evaluation of Proposed Changes Peach Bottom Atomic Power Station, Unit 2 Renewed Facility Operating License No. DPR-44

ATTACHMENT 1 CONTENTS

SUBJECT:

Safety Limit Minimum Critical Power Ratio Change 1.0

SUMMARY

DESCRIPTION 2.0 DETAILED DESCRIPTION

4.0 REGULATORY EVALUATION

4.1 Applicable Regulatory Requirements/Criteria 4.2 Precedents 4.3 No Significant Hazards Consideration 4.4 Conclusions

6.0 REFERENCES

License Amendment Request Attachment 1 Safety Limit Minimum Critical Power Ratio Page2 1.0

SUMMARY

DESCRIPTION This evaluation supports a request to amend Renewed Facility Operating License No. DPR-44 for Peach Bottom Atomic Power Station (PBAPS) Unit 2.

The proposed change modifies Technical Specification (TS) 2.1.1 ("Reactor Core SLs").

Specifically, a change to the Safety Limit Minimum Critical Power Ratio (SLMCPR) is requested to allow operation in the expanded Maximum Extended Load Line Limit Plus (MELLLA+)

operating domain. This change in being proposed to coincide with the PBAPS Unit 2 implementation of the MELLLA+ License Amendment Request (LAR) (Reference 1) requested for September 2015.

2.0 DETAILED DESCRIPTION The proposed change involves revising the SLMCPRs contained in TS 2.1.1 for two recirculation loop operation and single recirculation loop operation. The SLMCPR value for two recirculation loop operation is being changed from 2 1.10 to 2 1.15. The SLMCPR value for single recirculation loop operation is being changed from 2 1.14 to 2 1.15. This change is being proposed to coincide with the PBAPS Unit 2 implementation of the MELLLA+ LAR (Reference 1). A License Amendment Request (LAR) for implementation of the MELLLA+ operating strategy was submitted in Reference 1.

Two sets of reload licensing analyses were performed for PBAPS Unit 2 Cycle 21: one for operation without operation in the MELLLA+ operating domain and one with expanded operation to include the MELLLA+ operating domain. Performance of two sets of reload licensing analyses was necessary due to the restriction in the NRC approved License Topical Report (LTR) for Constant Pressure Power Uprate (Reference 3) that a licensee must first request and obtain a license for an Extended Power Uprate (EPU) prior to requesting a MELLLA+ power flow map expansion. The NRC approved the EPU for PBAPS Unit 2 and Unit 3 in August 2014 (Reference 4). Implementation of the EPU for PBAPS Unit 2 is planned for the fourth quarter of 2014 in operating Cycle 21. The second reload analysis with the MELLLA+ operating domain was performed for Cycle 21 assuming implementation would occur during Cycle 21 following NRC approval of the MELLLA+ LAR (Reference 1). As stated in Reference 1, Attachment 4, Section 2.2.1, based on the potential for MELLLA+ implementation affecting the SLMCPR, the NRC approved LTR for MELLLA+ (Reference 2) allows that the SLMCPR be calculated based on the actual core loading pattern for each reload core. During this second reload analysis it was determined that the cycle specific SLMCPR for PBAPS Unit 2 Cycle 21 in the MELLLA+ operating domain is not bounded by the current PBAPS Unit 2 TS value. Since the Cycle 21 core design and re-analysis were not completed at the time of the MELLLA+ LAR submittal, a separate LAR is necessary.

Marked up TS page 2.0-1 showing the requested changes is provided in Attachment 2. No changes are necessary to the TS Bases for this LAR. The retyped TS page 2.0-1 is provided in .

3.0 TECHNICAL EVALUATION

The proposed TS change will revise the SLMCPRs contained in TS 2.1.1 for two recirculation loop operation and single recirculation loop operation to reflect the changes in the cycle specific

License Amendment Request Attachment 1 Safety Limit Minimum Critical Power Ratio Page 3 analysis performed by Global Nuclear Fuel for PBAPS Unit 2 Cycle 21 with implementation of the MELLLA+ operating strategy.

The new SLMCPRs are calculated using NRG-approved methodology described in NEDE-24011-P-A, "General Electric Standard Application for Reactor Fuel," Revision 20 (Reference 5). A listing of the associated NRG-approved methodologies for calculating the SLMCPRs is provided in Section 1.0 ("Methodology") of Attachment 4.

The SLMCPR analysis establishes SLMCPR values that will ensure that during normal operation and during anticipated operational transients, at least 99.9% of all fuel rods in the core do not experience boiling transition if the limits are not violated. The SLMCPRs are calculated to include cycle specific parameters and, in general, are dominated by two key parameters: 1) flatness of the core bundle-by-bundle MCPR distribution, and 2) flatness of the bundle pin-by-pin power/R-Factor distribution. Information to support the cycle specific SLMCPRs is included in . That attachment summarizes the methodology, inputs, and results for the change in the SLMCPRs. The PBAPS Unit 2 Cycle 21 core consists of GNF2 fuel type only. contains the PBAPS Unit 2 Power I Flow Map for Cycle 21 that shows both the current MELLLA and the proposed MELLLA+ operating domains referred to in Section 2.9 of .

The proposed changes do not involve any new modes of operation, any changes to setpoints, or any plant modifications beyond those associated with the MELLLA+ LAR (Reference 1).

4.0 REGULATORY EVALUATION

4.1 Applicable Regulatory Requirements/Criteria 10 CFR 50.36, "Technical Specifications," paragraph (c)(1), requires that power reactor facility TS include safety limits for process variables that protect the integrity of certain physical barriers that guard against the uncontrolled release of radioactivity. The SLMCPR analysis establishes SLMCPR values that will ensure that during normal operation and during anticipated operational transients, at least 99.9% of all fuel rods in the core do not experience boiling transition if the limits are not violated. Thus, the SLMCPR is required to be contained in TS.

4.2 Precedents The NRC has approved a similar SLMCPR change at the following plant:

1. Letter from P. Tam (U.S. Nuclear Regulatory Commission) to T. J. O'Connor (Northern States Power Company - Minnesota), "Monticello Nuclear Generating Plant, Issuance of Amendment RE: Minimum Critical Power Ratio Safety Limit (TAC No. ME4790)," dated May 4, 2011 (ADAMS Accession No. ML11101A111)

License Amendment Request Attachment 1 Safety Limit Minimum Critical Power Ratio Page4 4.3 No Significant Hazards Consideration Exelon Generation Company, LLC (Exelon) has evaluated whether or not a significant hazards consideration is involved with the proposed amendment by focusing on the three standards set forth in 10 CFR 50.92, "Issuance of amendment," as discussed below:

1. Does the proposed amendment involve a significant increase in the probability or consequences of an accident previously evaluated?

Response: No.

The derivation of the cycle specific Safety Limit Minimum Critical Power Ratios (SLMCPRs) for incorporation into the Technical Specifications (TS), and their use to determine cycle specific thermal limits, has been performed using the methodology discussed in NEDE-24011-P-A, "General Electric Standard Application for Reactor Fuel," Revision 20 (Reference 5).

The basis of the SLMCPR calculation is to ensure that during normal operation and during anticipated operational transients, at least 99.9% of all fuel rods in the core do not experience boiling transition if the limit is not violated. The new SLMCPRs preserve the existing margin to boiling transition.

The MCPR safety limit is reevaluated for each reload using NRG-approved methodologies. The analyses for Peach Bottom Atomic Power Station (PBAPS) Unit 2 Cycle 21, with the addition of operation in the MELLLA+ operating domain, have concluded that a two recirculation loop MCPR safety limit of ~ 1.15, based on the application of Global Nuclear Fuel's NRG-approved MCPR safety limit methodology, will ensure that this acceptance criterion is met. For single recirculation loop operation, a MCPR safety limit of ~ 1.15 also ensures that this acceptance criterion is met. The MCPR operating limits are presented and controlled in accordance with the PBAPS Unit 2 Core Operating Limits Report (COLR).

The requested TS changes do not involve any additional plant modifications or operational changes that could affect system reliability or performance or that could affect the probability of operator error beyond those associated with the MELLLA+ LAR (Reference 1). The requested changes do not affect any postulated accident precursors, do not affect any accident mitigating systems, and do not introduce any new accident initiation mechanisms. Therefore, the proposed TS changes do not involve a significant increase in the probability or consequences of an accident previously evaluated.

2. Does the proposed amendment create the possibility of a new or different kind of accident from any accident previously evaluated?

Response: No.

The SLMCPR is a TS numerical value, calculated to ensure that during normal operation and during anticipated operational transients, at least 99.9% of all fuel rods in the core do not experience boiling transition if the limit is not violated. The new SLMCPRs are

License Amendment Request Attachment 1 Safety Limit Minimum Critical Power Ratio Page 5 calculated using NRG-approved methodology discussed in NEDE-24011-P-A, "General Electric Standard Application for Reactor Fuel," Revision 20 (Reference 5). The proposed changes do not involve any new modes of operation, any changes to setpoints, or any plant modifications beyond those associated with the MELLLA+ LAR (Reference 1). The proposed revised MCPR safety limits have been shown to be acceptable for Cycle 21 operation with the MELLLA+ operating domain. The core operating limits will continue to be developed using NRG-approved methods. The proposed MCPR safety limits or methods for establishing the core operating limits do not result in the creation of any new precursors to an accident. Therefore, this proposed change does not create the possibility of a new or different kind of accident from any previously evaluated.

3. Does the proposed amendment involve a significant reduction in a margin of safety?

Response: No.

There is no significant reduction in the margin of safety previously approved by the NRC as a result of the proposed change to the SLMCPRs. The new SLMCPRs are calculated using methodology discussed in NEDE-24011-P-A, "General Electric Standard Application for Reactor Fuel," Revision 20 (Reference 5). The SLMCPRs ensure that during normal operation and during anticipated operational transients, at least 99.9% of all fuel rods in the core do not experience boiling transition if the limits are not violated, thereby preserving the fuel cladding integrity. Therefore, the proposed TS changes do not involve a significant reduction in the margin of safety previously approved by the NRC.

Based on the above, Exelon concludes that the proposed amendment does not involve a significant hazards consideration under the standards set forth in 10 CFR 50.92(c), and, accordingly, a finding of no significant hazards consideration is justified.

4.4 Conclusions In conclusion, based on the considerations discussed above, (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.

5.0 ENVIRONMENTAL CONSIDERATION

A review has determined that the proposed amendment would change a requirement with respect to installation or use of a facility component located within the restricted area, as defined in 10 CFR 20, or would change an inspection or surveillance requirement. However, the proposed amendment does not involve (i) a significant hazards consideration, (ii) a significant change in the types or significant increase in the amounts of any effluent that may be released offsite, or (iii) a significant increase in individual or cumulative occupational radiation exposure. Accordingly, the proposed amendment meets the eligibility criterion for categorical exclusion set forth in 10 CFR 51.22(c)(9). Therefore, pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the proposed amendment.

License Amendment Request Attachment 1 Safety Limit Minimum Critical Power Ratio Page 6

6.0 REFERENCES

1. Exelon letter to the NRC, "License Amendment Request - Maximum Extended Load Line Limit Analysis Plus," dated September 4, 2014. (ADAMS Accession No. ML14247A503)

2. GE Hitachi Nuclear Energy, "General Electric Boiling Water Reactor Maximum Extended Load Line Limit Analysis Plus," NEDC-33006P-A, Revision 3, June 2009.

3. GE Hitachi Nuclear Energy, "Constant Pressure Power Uprate," NEDC-330004P-A, Revision 4, July 2003.

4. Letter from USNRC to Exelon Nuclear, Peach Bottom Atomic Power Station, Units 2 and 3 - Issuance of Amendment RE: Extended Power Uprate (TAC NOS. ME9631 and ME9632), dated August 25, 2014. (ADAMS Accession No. ML14133A046)

5. NEDE-24011-P-A, "General Electric Standard Application for Reactor Fuel,"

Revision 20.

ATTACHMENT 2 Markup of Technical Specifications Page Revised TS Page 2.0-1 (Unit 2)

SLs 2.0 2.0 SAFETY LIMITS (SLs)

2. 1 SLs 2.1.1 Reactor Core SLs 2.1.1.1 With the reactor steam dome pressure< 785 psig or core flow< 10% rated core flow:

THERMAL POWER shall be~ 23% RTP.

2.1.1.2 With the reactor steam dome pressure~ 785 psig and core flow~ 10% rated core flow: 1 . 1 1 15 MCPR shall be~~ for two recirculation loop operation or~ ~14 for single recirculation loop operation.

11.1s . _ _ I_ _: : . / ,

2.1.1.3 Reactor vessel water level shall be greater than the top of active irradiated fuel.

2.1.2 Reactor Coolant System Pressure SL Reactor steam dome pressure shall be~ 1325 psig.

2.2 SL Violations With any SL violation, the following actions shall be completed within 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />s:

2.2.1 Restore compliance with all SLs; and 2.2.2 Insert all insertable control rods.

(continued)

PBAPS UNIT 2 2.0-1 Amendment No. 293

ATTACHMENT 3 Retyped Technical Specifications Page Revised TS Page 2.0-1 (Unit 2)

SLs 2.0 2.0 SAFETY LIMITS (SLs) 2.1 SLs 2.1.1 Reactor Core SLs 2.1.1.1 With the reactor steam dome pressure< 785 psig or core flow< 10% rated core flow:

THERMAL POWER shall be~ 23% RTP.

2.1.1.2 With the reactor steam dome pressure~ 785 psig and core flow~ 10% rated core flow:

MCPR shall be~ 1.15 for two recirculation loop operation or~ 1.15 for single recirculation loop operation.

2.1.1.3 Reactor vessel water level shall be greater than the top of active irradiated fuel.

2.1.2 Reactor Coolant System Pressure SL Reactor steam dome pressure shall be~ 1325 psig.

2.2 SL Violations With any SL violation, the following actions shall be completed within 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />s:

2.2.1 Restore compliance with all SLs; and 2.2.2 Insert all insertable control rods.

(continued)

PBAPS UNIT 2 2.0-1 Amendment No.

ATTACHMENT 5 Non-Proprietary Version of Global Nuclear Fuel Report

Non-Proprietary Information - Class I (Public) 6 November 2014 PLM Report Specification 001N0184.3-NP GNF Additional Information Regarding the Requested Changes to the Technical Specification SLMCPR Peach Bottom Unit 2 Cycle 21 Copyright 2014 Global Nuclear Fuel - Americas, LLC All Rights Reserved Peach Bottom Unit 2 Cycle 21 Page 1 of27

Non-Proprietary Information - Class I (Public)

Information Notice This is a non-proprietary version of the document 001N0184.3-P, 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 (( )) .

Important Notice Regarding Contents of this Report Please Read Carefully The design, engineering, and other information contained in this document is furnished for the purpose of providing information regarding the requested changes to the Technical Specification SLMCPR for Exelon Peach Bottom Unit 2. The only undertakings of Global Nuclear Fuel-Americas, LLC (GNF-A) with respect to information in this document are contained in contracts between GNF-A and Exelon, and nothing contained in this document shall be construed as changing that contract. The use of this information by anyone other than Exelon, or for any purposes other than those for which it is intended is not authorized; and with respect to any unauthorized use, GNF-A makes no representation or warranty, and assumes no liability as to the completeness, accuracy, or usefulness of the information contained in this document.

Information Notice Page 2 of27

Non-Proprietary Information - Class I (Public)

Table of Contents 1.0 Methodology .............*.....................*.....................**......................*.............................*............................**.*..... 4 2.0 Discussion ......................................................................................................................................................... 4 2.1. Major Contributors to SLMCPR Change ..................................................................................................... .4 2.2. Deviations in NRC-Approved Uncertainties ................................................................................................. 5 2.2.1. R-Factor................................................................................................................................................. 5 2.2.2. Core Flow Rate and Random Effective TIP Reading............................................................................. 6 2.2.3. LPRM Update Interval and Calculated Bundle Power.......................................................................... 6 2.3. Departure from NRC-Approved Methodology .............................................................................................. 7 2.4. Fuel Axial Power Shape Penalty ................................................................................................................... 7 2.5. Methodology Restrictions .............................................................................................................................. 8 2.6. Minimum Core Flow Condition .................................................................................................................... 9 2.7. Limiting Control Rod Pattems ....................................................................................................................... 9 2.8. Core Monitoring System ................................................................................................................................ 9 2.9. Power/Flow Map ........................................................................................................................................... 9 2.10. Core Loading Diagram .............................................................................................................................. 9 2.11. Figure References ...................................................................................................................................... 9 2.12. Additional SLMCPR Licensing Conditions ............................................................................................ 10 2.13. 10 CFR 21 Evaluation .............................................................................................................................. 10 2.14. Summary .................................................................................................................................................. 10 3.0 References.........................................................................................**............................................................ 11 List of Figures Figure 1. Current Cycle Core Loading Diagram ........................................................................................................ 12 Figure 2. Previous Cycle Core Loading Diagram ....................................................................................................... 13 Figure 3. Figure 4.1 from NEDC-32601P-A .............................................................................................................. 14 Figure 4. Figure III.5-1 from NEDC-32601P-A ......................................................................................................... 15 Figure 5. Relationship Between MIP and CPR Margin .............................................................................................. 16 List of Tables Table 1. Description of Core ...................................................................................................................................... 17 Table 2. SLMCPR Calculation Methodologies .......................................................................................................... 18 Table 3. Monte Carlo Calculated SLMCPR vs. Estimate ........................................................................................... 19 Table 4. Non-Power Distribution Uncertainties ......................................................................................................... 21 Table 5. Power Distribution Uncertainties .................................................................................................................. 24 Table 6. Critical Power Uncertainties ......................................................................................................................... 27 Table of Contents Page 3 of27

Non-Proprietary Information - Class I (Public) 1.0 Methodology Global Nuclear Fuel (GNP) performs Safety Limit Minimum Critical Power Ratio (SLMCPR) calculations in accordance to NEDE-24011-P-A "General Electric Standard Application for Reactor Fuel" (Revision 20) using the following Nuclear Regulatory Commission (NRC)-

approved methodologies and uncertainties:

• NEDC-32601P-A, "Methodology and Uncertainties for Safety Limit MCPR Evaluations," August 1999.

• NEDC-32694P-A, "Power Distribution Uncertainties for Safety Limit MCPR Evaluations," August 1999.

• NEDC-32505P-A, "R-Factor Calculation Method for GEl l, GE12 and GE13 Fuel,"

Revision 1, July 1999.

The latter reference is applicable to GNF's current fuel offerings of GE14 and GNF2. Both are lOxlO lattice designs with two water rods, the same as GE12.

Table 2 identifies the methodologies used for the Peach Bottom Unit 2 Cycle 20 and Cycle 21 SLMCPR calculations.

2.0 Discussion In this discussion, the TLO nomenclature is used for two recirculation loops in operation, and the SLO nomenclature is used for one recirculation loop in operation.

2.1. Major Contributors to SLMCPR Change The calculated Monte Carlo SLMCPR values for the prior cycle and the current cycle are presented in Table 3.

In general, the calculated safety limit is dominated by two key parameters: (1) flatness of the core bundle-by-bundle Minimum Critical Power Ratio (MCPR) distribution; and (2) flatness of the bundle pin-by-pin power/R-Factor distribution. Greater flatness in either parameter yields more rods susceptible to boiling transition and thus a higher calculated SLMCPR. MCPR Importance Parameter (MIP) measures the core bundle-by-bundle MCPR distribution and R-Factor Importance Parameter (RIP) measures the bundle pin-by-pin power/R-Factor distribution. The effect of the fuel loading pattern on the calculated TLO SLMCPR has been correlated to the parameter MIPRIP, which combines the MIP and RIP values.

Another factor besides core MCPR distribution or bundle R-factor distribution that significantly affects the SLMCPR is the expansion of the analysis domain that comes with the initial application of Maximum Extended Load Line Limit Analysis Plus (MELLLA+). The rated Methodology Page 4 of27

Non-Proprietary Information - Class I (Public) power/minimum core flow point is analyzed at a lower core flow (than without MELLLA+)

using increased uncertainties (see Section 2.2.2) that tend to increase the SLMCPR. Also, a new point at off-rated power/off-rated flow is analyzed using the increased uncertainties. It is expected that in most cases this off-rated power/off-rated flow point will set the overall limit.

Table 3 presents the MIP and RIP parameters for the previous cycle and the current cycle along with the TLO SLMCPR estimates using MIPRIP correlations. The MIPRIP prediction is correlated to Monte Carlo results for rated power/rated flow. Predictions for the MELLLA+

domains (at rated power/minimum core flow and off-rated power/off-rated core flow) must be adjusted by an amount estimated to account for the effect of the larger (SLO) uncertainties. In addition, Table 3 presents estimated effects on the TLO SLMCPR due to methodology deviations, penalties, and/or uncertainty deviations from approved values. Based on the MIPRIP correlation and any effects due to deviations from approved values, a final estimated TLO SLMCPR is determined. Table 3 also provides the actual calculated Monte Carlo SLMCPR.

Given the bias and uncertainty in the MIPRIP correlation (( ))

and the inherent variation in the Monte Carlo results (( )), the change in the Peach Bottom Unit 2 Cycle 21 calculated Monte Carlo TLO SLMCPR is consistent with the corresponding estimated TLO SLMCPR value.

The intent of the final estimated TLO SLMCPR is to provide an estimate to check the reasonableness of the Monte Carlo result. It is not used for any other purpose. The methodology and final SLMCPR is based on the rigorous Monte Carlo analysis.

The items in Table 3 that result in the increase of the estimated SLMCPR are discussed in Section 2.2.

2.2. Deviations in NRC-Approved Uncertainties Tables 4 and 5 provide a list of NRC-approved uncertainties along with values actually used. A discussion of deviations from these NRC-approved values follows; all of which are conservative relative to NRC-approved values. Also, the estimated effect on the SLMCPR is provided in Table 3 for each deviation.

2.2.1. R-Factor At this time, GNF has generically increased the GEXL R-Factor uncertainty from ((

)) to account for an increase in channel bow due to the emerging unforeseen phenomena called control blade shadow corrosion-induced channel bow, which is not accounted for in the channel bow uncertainty component of the approved R-Factor uncertainty. The step "cr RPEAK" in Figure 4.1 from NEDC-32601P-A, which has been provided for convenience in Figure 3, is affected by this deviation. Reference 4 technically justifies that a GEXL R-Factor uncertainty of

(( )) accounts for a channel bow uncertainty of up to (( )).

Discussion Page 5 of27

Non-Proprietary Information - Class I (Public)

Peach Bottom Unit 2 has experienced control blade shadow corrosion-induced channel bow to the extent that an increase in the NRC-approved R-Factor uncertainty (( )) is deemed prudent to address its effect. Accounting for the control blade shadow corrosion-induced channel bow, the Peach Bottom Unit 2 Cycle 21 analysis shows an expected channel bow uncertainty of (( )), which is bounded by a GEXL R-Factor uncertainty of (( )).

Thus the use of a GEXL R-Factor uncertainty of (( )) adequately accounts for the expected control blade shadow corrosion-induced channel bow for Peach Bottom Unit 2 Cycle 21.

2.2.2. Core Flow Rate and Random Effective TIP Reading In Reference 5, GNF committed to the expansion of the state points used in the determination of the SLMCPR. Consistent with the Reference 5 commitments, GNF performs analyses at the rated core power and minimum licensed core flow point in addition to analyses at the rated core power and rated core flow point. The approved SLMCPR methodology is applied at each state point that is analyzed.

For the TLO calculations performed in the MELLLA+ domain at rated power/minimum core flow and off-rated power/off-rated core flow, the approved uncertainty values for the core flow rate (2.5%) and the random effective Traversing In-Core Probe (TIP) reading (1.2%) are conservatively adjusted by using the SLO uncertainty values of 6.0% and 2.85% for the core flow rate and random effective TIP reading respectively. The steps "a CORE FLOW" and "a TIP (INSTRUMENT)" in Figure 4.1 from NEDC-32601P-A, which has been provided for convenience in Figure 3, are affected by this deviation, respectively.

The treatment of the core flow and random effective TIP reading uncertainties is based on the assumption that the signal to noise ratio deteriorates as core flow is reduced. GNF believes this is conservative.

2.2.3. LPRM Update Interval and Calculated Bundle Power To address the Local Power Range Monitor (LPRM) update/calibration interval in the Peach Bottom Unit 2 Technical Specifications, GNF has increased the LPRM update uncertainty in the SLMCPR analysis for Peach Bottom Unit 2 Cycle 21. The approved uncertainty values for the contribution to bundle power uncertainty due to LPRM update, (( )) and the resulting total uncertainty in calculated bundle power, (( )) are conservatively increased, as shown in Table 5. The steps "a TIP (INSTRUMENT)" and "a BUNDLE (MODEL)" in Figure 4.1 from NEDC-32601P-A, which has been provided for convenience in Figure 3, are affected by this difference.

((

Discussion Page 6 of27

Non-Proprietary Information - Class I (Public)

)) The total bundle power uncertainty is a function of the LPRM update uncertainty as detailed in Section 3.3 of NEDC-32694P-A.

2.3. Departure from NRC-Approved Methodology No departures from NRC-approved methodologies were used in the Peach Bottom Unit 2 Cycle 21 SLMCPR calculations.

2.4. Fuel Axial Power Shape Penalty At this time, GNF has determined that higher uncertainties and non-conservative biases in the GEXL correlations for the various types of axial power shapes (i.e., inlet, cosine, outlet, and double hump) could potentially exist relative to the NRC-approved methodology values (References 3, 6, 7, and 8). The following table identifies, by marking with an "X", this potential for each GNF product line currently in use:

((

))

Axial bundle power shapes corresponding to the limiting SLMCPR control blade patterns are determined using the PANACEA 3D core simulator. These axial power shapes are classified in accordance to the following table:

((

))

Discussion Page 7 of27

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If the limiting bundles in the SLMCPR calculation exhibit an axial power shape identified by this table, GNF penalizes the GEXL critical power uncertainties to conservatively account for the effect of the axial power shape. Table 6 provides a list of the GEXL critical power uncertainties determined in accordance to the NRC-approved methodology contained in NEDE-24011-P-A along with values actually used.

For the limiting bundles, the fuel axial power shapes in the SLMCPR analysis were examined to determine the presence of axial power shapes identified in the above table. These power shapes were not found; therefore, no power shape penalties were applied to the calculated Peach Bottom Unit 2 Cycle 21 SLMCPR values.

2.5. Methodology Restrictions The four restrictions identified on Page 3 of NRC' s Safety Evaluation (SE) relating to the General Electric (GE) Licensing Topical Reports (LTRs) NEDC-32601P, NEDC-32694P, and Amendment 25 to NEDE-24011-P-A (March 11, 1999) are addressed in References 1, 2, 3, and 9.

The four restrictions for GNF2 were determined acceptable by the NRC review of "GNF2 Advantage Generic Compliance with NEDE-24011-P-A (GESTAR II)," NEDC-33270P, Revision 0, FLN-2007-011, March 14, 2007. Specifically, in the NRC audit report ML081630579 for the said document, Section 3.4.1 (page 59) states:

"The NRC staffs SE of NEDC-32694P-A (Reference 19 of NEDC-33270P) provides four actions to follow whenever a new fuel design is introduced. These four conditions are listed in Section 3.0 of the SE. The analysis and evaluation of the GNF2 fuel design was evaluated in accordance with the limitations and conditions stated in the NRC staffs SE, and is acceptable."

GNF's position is that GNF2 is an evolutionary fuel product based on GE14. It is not considered a new fuel design as it maintains the previously established 1Ox10 array and 2 water rod makeup, as stated by the NRC audit report ML081630579, Section 3.4.2.2.1 (page 59):

"The NRC staff finds that the calculational methods, evaluations and applicability of the OLMCPR and SLMCPR are in accordance with existing NRC-approved methods and thus valid for use with GNF2 fuel."

As such, no new GNF fuel designs are being introduced in Peach Bottom Unit 2 Cycle 21; therefore, the NEDC-32505P-A statement" .. .if new fuel is introduced, GENE must confirm that the revised R-Factor method is still valid based on new test data" is not applicable.

Discussion Page 8 of27

Non-Proprietary Information - Class I (Public) 2.6. Minimum Core Flow Condition For Peach Bottom Unit 2 Cycle 21, the most limiting SLMCPR calculation occurred at the 78.8% rated power/55.0% rated flow point. At low core flows, the search spaces for the limiting rod pattern and the nominal rod pattern are essentially the same. Additionally, the condition that MIP (( )) establishes a reasonably bounding limiting rod pattern. Hence, the rod pattern used to calculate the SLMCPR at 78.8% rated power/55.0% rated flow reasonably assures that at least 99.9% of the fuel rods in the core would not be expected to experience boiling transition during normal operation or anticipated operational occurrences during the operation of Peach Bottom Unit 2 Cycle 21. Consequently, the SLMCPR value calculated from the 78.8% rated power/55.0% rated core flow condition limiting MCPR distribution reasonably bounds this mode of operation for Peach Bottom Unit 2 Cycle 21.

2.7. Limiting Control Rod Patterns The limiting control rod patterns used to calculate the SLMCPR reasonably assure that at least 99.9% of the fuel rods in the core would not be expected to experience boiling transition during normal operation or anticipated operational occurrences during the operation of Peach Bottom Unit 2 Cycle 21.

2.8. Core Monitoring System For Peach Bottom Unit 2 Cycle 21, the 3DMONICORE system will be used as the core monitoring system.

2.9. Power/Flow Map The utility has provided the current and previous cycle power/flow map in a separate document.

2.10. Core Loading Diagram Figures 1 and 2 provide the core-loading diagram for the current and previous cycle respectively, which are the Reference Loading Pattern as defined by NEDE-24011-P-A. Table 1 provides a description of the core.

2.11. Figure References Figure 3 is Figure 4.1 from NEDC-32601P-A. Figure 4 is Figure IIl.5-1 from NEDC-32601P-A.

Figure 5 is based on Figure III.5-2 from NEDC-32601P-A, and has been updated with GE14 and GNF2 data.

Discussion Page 9 of27

Non-Proprietary Information - Class I (Public) 2.12. Additional SLMCPR Licensing Conditions For Peach Bottom Unit 2 Cycle 21, the additional SLMCPR licensing condition that the SLMCPR shall be established by adding 0.02 (Reference 10) to the cycle-specific SLMCPR value calculated using the NRC-approved methodologies documented in NEDE-24011-P-A has been applied (see Table 3).

2.13. 10 CFR 21 Evaluation There are no known 10 CFR 21 factors that affect the Peach Bottom Unit 2 Cycle 21 SLMCPR calculations.

2.14. Summary The requested changes to the Technical Specification SLMCPR values are 1.15 for TLO and 1.15 for SLO for Peach Bottom Unit 2 Cycle 21. These values bound the calculated results for Peach Bottom Unit 2 Cycle 21.

Discussion Page 10 of27

Non-Proprietary Information - Class I (Public) 3.0 References

1. Letter, Glen A. Watford (GNF-A) to NRC Document Control Desk with attention to R. Pulsifer (NRC), "Confirmation of 1Ox10 Fuel Design Applicability to Improved SLMCPR, Power Distribution and R-Factor Methodologies," FLN-2001-016, September 24, 2001.

2. Letter, Glen A. Watford (GNF-A) to NRC Document Control Desk with attention to Joseph E. Donoghue (NRC), "Confirmation of the Applicability of the GEXL 14 Correlation and Associated R-Factor Methodology for Calculating SLMCPR Values in Cores Containing GE14 Fuel," FLN-2001-017, October 1, 2001.

3. Letter, Glen A. Watford (GNF-A) to NRC Document Control Desk with attention to Joseph E. Donoghue (NRC), "Final Presentation Material for GEXL Presentation -

February 11, 2002," FLN-2002-004, February 12, 2002.

4. Letter, John F. Schardt (GNF-A) to NRC Document Control Desk with attention to Mel B.

Fields (NRC), "Shadow Corrosion Effects on SLMCPR Channel Bow Uncertainty,"

FLN-2004-030, November 10, 2004.

5. Letter, Jason S. Post (GENE) to NRC Document Control Desk with attention to Chief, Information Management Branch, et al. (NRC), "Part 21 Final Report: Non-Conservative SLMCPR," MFN 04-108, September 29, 2004.

6. Letter, Glen A. Watford (GNF-A) to NRC Document Control Desk with attention to Alan Wang (NRC), "NRC Technology Update - Proprietary Slides - July 31 - August 1, 2002,"

FLN-2002-015, October 31, 2002.

7. Letter, Jens G. Munthe Andersen (GNF-A) to NRC Document Control Desk with attention to Alan Wang (NRC), "GEXL Correlation for lOXlO Fuel," FLN-2003-005, May 31, 2003.

8. Letter, Andrew A. Lingenfelter (GNF-A) to NRC Document Control Desk with cc to Michelle C. Honcharik (NRC), "Removal of Penalty Being Applied to GE14 Critical Power Correlation for Outlet Peaked Axial Power Shapes," FLN-2007-031, September 18, 2007.

9. Letter, Andrew A. Lingenfelter (GNF-A) to NRC Document Control Desk with cc to Stephen S. Philpott (NRC), "Amendment 33 to NEDE-24011-P, General Electric Standard Application for Reactor Fuel (GESTAR II) and GNF2 Advantage Generic Compliance with NEDE-24011-P-A (GESTAR II), NEDC-33270P, Revision 3, March 2010," MFN 10-045, March 5, 2010.

10. Applicability of GE Methods to Expanded Operating Domains, Licensing Topical Report, NEDC-33173P-A, Revision 4, November 2012.

References Page 11 of27

Non-Proprietary Information - Class I (Public) 60 10 19 11 19 19 8 8 8 8 19 19 20 21 20 58 9 8 19 8 26 24 22 22 22 22 24 26 20 19 8 9 56 19 20 8 1 23 26 4 25 4 24 24 4 25 4 26 23 1 20 8 10 54 11 8 22 4 4 4 4 5 4 5 5 4 5 4 4 4 4 22 8 11 52 8 1 25 4 13 12 28 6 27 3 27 27 3 27 6 28 12 13 4 25 8 1 50 11 8 19 25 4 4 12 25 6 6 7 26 5 5 26 7 6 6 25 12 4 4 25 19 19 11 48 20 8 25 4 25 12 25 6 22 3 25 5 24 24 5 25 3 22 6 25 12 25 4 25 8 8 46 9 8 22 4 4 12 26 6 25 3 22 5 25 3 3 25 5 22 3 25 6 26 12 4 4 22 8 9 44 20 8 10 4 13 12 25 6 28 12 22 5 24 3 24 24 3 24 5 22 12 28 6 25 12 13 4 10 8 19 42 21 11 23 4 12 25 6 25 12 22 2 23 3 26 5 5 26 3 23 2 22 12 25 6 25 12 4 23 11 8 40 19 8 26 4 28 6 22 3 22 2 25 3 27 2 24 24 2 27 3 25 2 22 3 22 6 28 4 26 8 9 38 9 26 4 4 6 6 3 22 5 23 3 26 5 22 7 7 22 5 26 3 23 5 22 3 6 6 4 4 26 19 36 8 24 25 5 27 7 25 5 24 3 27 5 28 3 26 26 3 28 5 27 3 24 5 25 7 27 5 25 24 8 34 20 22 4 4 3 26 5 25 3 26 2 22 3 25 5 5 25 3 22 2 26 3 25 5 26 3 4 4 22 11 32 8 22 24 5 27 5 24 3 24 5 24 7 26 5 22 22 5 26 7 24 5 24 3 24 5 27 5 24 22 8 30 8 22 24 5 27 5 24 3 24 5 24 7 26 5 22 22 5 26 7 24 5 24 3 24 5 27 5 24 22 8 28 19 22 4 4 3 26 5 25 3 26 2 22 3 25 5 5 25 3 22 2 26 3 25 5 26 3 4 4 22 8 26 8 24 25 5 27 7 25 5 24 3 27 5 28 3 26 26 3 28 5 27 3 24 5 25 7 27 5 25 24 8 24 19 26 4 4 6 6 3 22 5 23 3 26 5 22 7 7 22 5 26 3 23 5 22 3 6 6 4 4 26 9 22 9 19 26 4 28 6 22 3 22 2 25 3 27 2 24 24 2 27 3 25 2 22 3 22 6 28 4 26 8 19 20 21 8 23 4 12 25 6 25 12 22 2 23 3 26 5 5 26 3 23 2 22 12 25 6 25 12 4 23 11 21 18 20 8 10 4 13 12 25 6 28 12 22 5 24 3 24 24 3 24 5 22 12 28 6 25 12 13 4 10 8 20 16 9 8 22 4 4 12 26 6 25 3 22 5 25 3 3 25 5 22 3 25 6 26 12 4 4 22 8 9 14 8 1 25 4 25 12 25 6 22 3 25 5 24 24 5 25 3 22 6 25 12 25 4 25 20 1 12 11 19 8 25 4 4 12 25 6 6 7 26 5 5 26 7 6 6 25 12 4 4 25 8 19 11 10 8 20 25 4 13 12 28 6 27 3 27 27 3 27 6 28 12 13 4 25 19 8 8 11 20 22 4 4 4 4 5 4 5 5 4 5 4 4 4 4 22 20 11 6 10 8 8 1 23 26 4 25 4 24 24 4 25 4 26 23 1 8 8 10 4 9 11 19 8 26 24 22 22 22 22 24 26 8 19 8 9 2 11 8 20 19 19 8 8 8 8 19 19 20 19 11 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51 53 55 57 59 Fuel Type 1=GNF2-PlODG2B393-15GZ-lOOT2-150-T6-3334 (Cycle 19) 13=GNF2-Pl ODG2B417-2G8.0/10G7.0-100T2-150-T6-4288 (Cycle 21) 2=GNF2-Pl ODG2B403-14GZ-1 OOT2-150-T6-4285 (Cycle 21) 19=GNF2-P 1ODG2B388-6G8.0/6G7.0/2G6.0-1 OOT2-150-T6-3336 3=GNF2-Pl ODG2B403-14GZ-1 OOT2-150-T6-4285 (Cycle 21) (Cycle 19) 4=GNF2-PlODG2B417-2G8.0/lOG7.0-lOOT2-150-T6-4288 (Cycle 21) 20=GNF2-P10DG2B392-15GZ-100T2-150-T6-3335 (Cycle 19) 5=GNF2-P10DG2B402-13G8.0-100T2-150-T6-4286 (Cycle 21) 21 =GNF2-P10DG2B392-15GZ-100T2-150-T6-3332 (Cycle 19) 6=GNF2-P 1ODG2B409-14GZ-1 OOT2-150-T6-4287 (Cycle 21) 22=GNF2-P10DG2B392-15GZ-100T2-150-T6-3335 (Cycle 20) 7=GNF2-P10DG2B402-13G8.0-100T2-150-T6-4286 (Cycle 21) 23=GNF2-P10DG2B397-14GZ-100T2-150-T6-4128 (Cycle 20) 8=GNF2-PlODG2B406-12G6.0-lOOT2-150-T6-3337 (Cycle 19) 24=GNF2-PlODG2B399-11G7.0/2G6.0-lOOT2-150-T6-4130 (Cycle 20) 9=GNF2-PlODG2B393-15GZ-lOOT2-150-T6-3334 (Cycle 19) 25=GNF2-PlODG2B403-12GZ-lOOT2-150-T6-4129 (Cycle 20) 1O=GNF2-P lODG2B388-6G8.0/6G7.0/2G6.0-lOOT2-l 50-T6-3336 26=GNF2-P10DG2B392-15GZ-100T2-150-T6-3335 (Cycle 20)

(Cycle 19) 27=GNF2-P10DG2B397-14GZ-100T2-150-T6-4128 (Cycle 20) 11 =GNF2-P10DG2B392-15GZ-100T2-150-T6-3335 (Cycle 19) 28=GNF2-P10DG2B403-12GZ-100T2-150-T6-4129 (Cycle 20) 12=GNF2-Pl ODG2B409-14GZ-1 OOT2-150-T6-4287 (Cycle 21)

Figure 1. Current Cycle Core Loading Diagram Figure 1. Current Cycle Core Loading Diagram Page 12 of27

Non-Proprietary Information - Class I (Public) 60 17 18 17 15 14 15 18 18 15 14 15 17 18 17 58 16 14 18 17 15 14 14 18 18 14 14 15 17 18 14 16 56 15 15 17 14 14 19 20 8 11 8 8 11 8 20 19 14 14 17 15 15 54 16 14 15 1 8 25 25 8 25 28 28 25 8 25 25 8 1 15 14 16 52 14 18 18 8 25 24 25 24 25 22 19 19 22 25 24 25 24 25 8 18 18 14 50 17 16 18 10 8 24 25 8 24 19 25 11 24 24 11 25 19 24 8 25 24 8 10 18 16 17 48 15 14 18 8 19 28 22 25 11 26 11 22 19 19 22 11 26 11 25 22 28 19 8 18 14 15 46 16 17 17 8 24 28 19 22 9 26 8 23 11 26 26 11 23 8 26 9 22 19 28 24 8 17 17 16 44 17 14 14 1 25 25 22 22 21 26 21 23 11 27 21 21 27 11 23 21 26 21 22 22 25 25 1 14 14 17 42 18 18 18 8 24 8 25 9 26 10 22 11 26 19 22 22 19 26 11 22 10 26 9 25 8 24 8 18 18 18 40 15 15 19 25 25 24 11 26 21 22 20 26 10 24 19 19 24 10 26 20 22 21 26 11 24 25 25 19 15 15 38 15 18 20 25 24 19 26 8 23 11 26 20 22 21 27 27 21 22 20 26 11 23 8 26 19 24 25 20 18 15 36 17 18 8 8 25 25 11 23 11 26 10 22 21 27 10 10 27 21 22 10 26 11 23 11 25 25 8 8 18 17 34 15 14 11 25 22 11 22 11 27 19 24 21 27 9 22 22 9 27 21 24 19 27 11 22 11 22 25 11 14 15 32 18 15 8 28 19 24 19 26 21 22 19 27 10 22 9 9 22 10 27 19 22 21 26 19 24 19 28 8 15 18 30 18 15 8 28 19 24 19 26 21 22 19 27 10 22 9 9 22 10 27 19 22 21 26 19 24 19 28 8 15 18 28 15 14 11 25 22 11 22 11 27 19 24 21 27 9 22 22 9 27 21 24 19 27 11 22 11 22 25 11 18 15 26 17 18 8 8 25 25 11 23 11 26 10 22 21 27 10 10 27 21 22 10 26 11 23 11 25 25 8 8 18 17 24 15 18 20 25 24 19 26 8 23 11 26 20 22 21 27 27 21 22 20 26 11 23 8 26 19 24 25 20 18 15 22 15 15 19 25 25 24 11 26 21 22 20 26 10 24 19 19 24 10 26 20 22 21 26 11 24 25 25 19 15 15 20 18 18 18 8 24 8 25 9 26 10 22 11 26 19 22 22 19 26 11 22 10 26 9 25 8 24 8 14 18 18 18 17 14 14 1 25 25 22 22 21 26 21 23 11 27 21 21 27 11 23 21 26 21 22 22 25 25 1 14 14 17 16 16 17 17 8 24 28 19 22 9 26 8 23 11 26 26 11 23 8 26 9 22 19 28 24 8 17 17 16 14 15 14 18 8 19 28 22 25 11 26 11 22 19 19 22 11 26 11 25 22 28 19 8 18 14 15 12 17 16 18 10 8 24 25 8 24 19 25 11 24 24 11 25 19 24 8 25 24 8 10 18 16 17 10 14 18 18 8 25 24 25 24 25 22 19 19 22 25 24 25 24 25 8 18 18 14 8 16 14 15 1 8 25 25 8 25 28 28 25 8 25 25 8 1 15 14 16 6 15 15 17 14 14 19 20 8 11 8 8 11 8 20 19 14 14 17 15 15 4 16 14 18 17 15 14 14 18 18 14 14 15 17 18 14 16 2 17 18 17 15 14 15 18 18 15 14 15 17 18 17 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51 53 55 57 59 Fuel Type 1=GNF2-P10DG2B393-15GZ-100T2-150-T6-3334 (Cycle 19) 19=GNF2-P10DG2B388-6G8.0/6G7.0/2G6.0-100T2-150-T6-3336 8=GNF2-PlODG2B406-12G6.0-lOOT2-150-T6-3337 (Cycle 19) (Cycle 19) 9=GNF2-P10DG2B393-15GZ-100T2-150-T6-3334 (Cycle 19) 20=GNF2-P10DG2B392-15GZ-100T2-150-T6-3335 (Cycle 19) 1O=GNF2-P1ODG2B388-6G8.0/6G7.0/206.0-1OOT2-l50-T6-3 336 2l=GNF2-P10DG2B392-15GZ-100T2-150-T6-3332 (Cycle 19)

(Cycle 19) 22=GNF2-P10DG2B392-15GZ-100T2-150-T6-3335 (Cycle 20) 11 =GNF2-P10DG2B392-15GZ-100T2-150-T6-3335 (Cycle 19) 23=GNF2-P10DG2B397-14GZ-100T2-150-T6-4128 (Cycle 20) 14=GE14-P10DNAB420-13GZ-100T-150-T6-3097 (Cycle 18) 24=GNF2-P10DG2B399-11G7.0/2G6.0-100T2-150-T6-4130 (Cycle 20) 15=GE14-P10DNAB416-15GZ-100T-150-T6-3098 (Cycle 18) 25=GNF2-P10DG2B403-12GZ-100T2-150-T6-4129 (Cycle 20) 16=GE14-P10DNAB416-15GZ-100T-150-T6-2911 (Cycle 18) 26=GNF2-Pl ODG2B392-15GZ-1 OOT2-150-T6-3335 (Cycle 20) 17=GE 14-P10DNAB41 l-15GZ-100T-150-T6-3099 (Cycle 18) 27=GNF2-PlODG2B397-14GZ-100T2-150-T6-4128 (Cycle 20) 18=GE14-P10DNAB409-15GZ-100T-150-T6-2913 (Cycle 18) 28=GNF2-P10DG2B403-12GZ-100T2-150-T6-4129 (Cycle 20)

Figure 2. Previous Cycle Core Loading Diagram Figure 2. Previous Cycle Core Loading Diagram Page 13 of27

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((

))

Figure 3. Figure 4.1 from NEDC-32601P-A Figure 3. Figure 4.1 from NEDC-32601P-A Page 14 of27

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((

))

Figure 4. Figure 111.5-1 from NEDC-32601P-A Figure 4. Figure 111.5-1 from NEDC-32601P-A Page 15 of27

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((

))

Figure 5. Relationship Between MIP and CPR Margin Figure 5. Relationship Between MIP and CPR Margin Page 16 of27

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Table 1. Description of Core Previous Cy,~le:. Previous Cycle Current Rated Power :*~ ~:, Rated Power OtJ-Rated Min.

tm.u,m. , .Ft . : ~*

.~

Rated . - ..- Off-Rated Core Flow -. *~ ~~.. Core Flow hniting.case Limiting Case Number of Bundles in the Core I 764 I 764 Limiting Point (i.e.,

Beginning of Cycle (BOC)/Middle of I EOR I EOR I MOC I EOR I MOC I MOC Cycle (MOC)/End of Cycle (EOC))

Cycle Exposure at Limiting Point I 13,400 I 13,400 I 7,000 I 12,275 I 7,500 I 7,700 (MWd/STU)

% Rated Core Power I 100.0 I 100.0 I 78.8 I 100.0 I 100.0 I 100.0

% Rated Core Flow I 82.8 I 100.0 I 55.0 I 83.0 I 100.0 I 110.0 Reload Fuel Type I GNF2 I GNF2 Latest Reload I 37.7 I 42.9 Batch Fraction,%

Latest Reload Average Batch, I 3.97 I 4.08 Wt% Enrichment Core Fuel,%

GNF2 73.3 I 100.

GE14 I 26.7 Core Average I 4.01 I 4.02 Wt% Enrichment Table 1. Description of Core Page 17 of27

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Table 2. SLMCPR Calculation Methodologies Description Non-Power Distribution NEDC-32601P-A NEDC-32601P-A Uncertainty Power Distribution NEDC-32601P-A NEDC-32601P-A Methodology Power Distribution NEDC-32694P-A NEDC-32694P-A Uncertainty Core Monitoring System 3DMONICORE 3DMONICORE R-Factor Calculation NEDC-32505P-A NEDC-32505P-A Methodology Table 2. SLMCPR Calculation Methodologies Page 18 of27

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Table 3. Monte Carlo Calculated SLMCPR vs. Estimate Previq;U~l{:ycle 'revious Cycle; Current Cycle ' Ciiff~tii.i RatedPow~r Rated Power , -OJr-Rated Pow~r Rated'l'd Minimum Rated - --~~ -~. ofi-nted ri!*" ""' -

Minimum CoreFJow . Cote _F low CQre _Flow Limitfug Case Limiting Cue Limiting Case-

((

Table 3. Monte Carlo Calculated SLMCPR vs. Estimate Page 19 of27

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Table 3. Monte Carlo Calculated SLMCPR vs. Estimate Previous* Cyqe PP~fiwili Cycle Cµ.rrent Cycle Current Cycle Current Cycle

~-Rated Power kat~Power Of[-Rated Power ~tedPower -Rated Power Minimum Rated Oft-rated Minimum Rated Core Flow Core Flow

• CoreFlow Limiting Case Limiting Case Limiting Case

))

Note:

(( ))

Table 3. Monte Carlo Calculated SLMCPR vs. Estimate Page 20 of27

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Table 4. Non-Power Distribution Uncertainties c(iiff~ilt Cycle .,..

Off-Rated J>ower

()ff-Jhted Core Flow Core Flow Limiting Limiting

"- Case Case GETAB Feedwater Flow 1.76 NIA NIA NIA NIA NIA NIA Measurement Feedwater Temperature 0.76 NIA NIA NIA NIA NIA NIA Measurement Reactor Pressure 0.50 NIA NIA NIA NIA NIA NIA Measurement Core Inlet Temperature 0.20 NIA NIA NIA NIA NIA NIA Measurement Total Core 2.5 TLO Flow 6.0 SLO NIA NIA NIA NIA NIA NIA Measurement Channel Flow Area Variation 3.0 NIA NIA NIA NIA NIA NIA Friction Factor Multiplier 10.0 NIA NIA NIA NIA NIA NIA Table 4. Non-Power Distribution Uncertainties Page 21 of27

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Table 4. Non-Power Distribution Uncertainties Current Cycle Rated Power

• Minimum Core Flow Core Flow Limiting Limiting

. Case Case Channel Friction Factor 5.0 NIA NIA NIA NIA NIA NIA

' Multiplier NEDC-32601P-A Feedwater Flow I (( )) I (( )) I (( )) I (( )) I (( )) I (( )) I (( ))

Measurement Feedwater Temperature Measurement I (( )) I (( )) I (( )) I (( )) I (( )) I (( )) I (( ))

Reactor Pressure I (( )) I (( )) I (( )) I (( )) I (( )) I (( )) I (( ))

Measurement Core Inlet Temperature I 0.2 I 0.2 I 0.2 I 0.2 I 0.2 I 0.2 I 0.2 Measurement Total Core 2.5 TLO 3.02 TLO 2.5 TLO 2.5 TLO 2.5 TLO Flow 6.0TLO 6.0TLO Measurement I 6.0 SLO I 6.0 SLO I 6.0 SLO I I I 6.0 SLO I 6.0 SLO Table 4. Non-Power Distribution Uncertainties Page 22 of27

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Table 4. Non-Power Distribution Uncertainties P;revigus Current

['Cycle Cycle Rated Pnwer Off-Rated Power*

Rated Off-Rated Table 4. Non-Power Distribution Uncertainties Page 23 of27

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Table 5. Power Distribution Uncertainties Previous Previous Cycle *~" :;"T; - Cycle Rated~ower Rated Power Off-Rated PdW~r Mihlmum Rated *  : . Off-Rated CoreFlow ~ ~ CoreFlow *d Core Flow :,*;: : Core Flow '.'~ Col9e Flow

. ._ JI * ~ ~ t'*,.. * -- * * -.... * . * *

• Limiting "' Limiting  ;::i;~ L*UJiting *~ri, }~=-=-, LUD.J.ting  ;*_ :::~. Lumting Case ,. - r Case -

~_... c ase- * '%~~ :~v~*

~**"- -{'- ~'-~*.

Case - *:. n\ . . .. c ase GETAB/NEDC-32601P-A GEXL R-Factor I (( )) I (( )) I (( )) I (( )) I (( )) I (( )) I (( ))

Random 1.2 TLO Effective TIP I 2.85 SLO I NIA I NIA I NIA I NIA I NIA I NIA Reading Systematic Effective TIP I 8.6 I NIA I NIA I NIA I NIA I NIA I NIA Reading NEDC-32694P-A, 3DMONICORE GEXL R-Factor I (( )) I (( )) I (( )) I (( )) I (( )) I (( )) I (( ))

Random 1.2 TLO 1.45 TLO 1.2 TLO 1.2 TLO 1.2 TLO Effective TIP I 2.85 SLO I 2.85 SLO I 2.85 SLO I 2.85 TLO I 2.85 TLO I 2.85 SLO I 2.85 SLO Reading TIP Integral I (( )) I (( )) I (( )) I (( )) I (( )) I (( )) I (( ))

Table 5. Power Distribution Uncertainties Page 24 of27

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Table 5. Power Distribution Uncertainties

?revious ~-

Cycl~ " , -< °'* - Cyc~~

Rated Power ~ Otl-Ra~ Power Rated , * -._, Off-Rated Core *Flf)W Eim!Ong

--*r*.... ---~ ~ --~ - I -. --~ *. - ,. ~- ,. . **- Case Four Bundle Power Distribution I (( )) I (( )) I (( )) I (( )) I (( )) I (( )) I (( ))

Surrounding TIP Location Contribution to Bundle Power Uncertainty I (( )) I (( )) I (( )) I (( )) I (( )) I (( )) I (( ))

DuetoLPRM Update Contribution to Bundle Power Due to I (( )) I (( )) I (( )) I (( )) I (( )) I (( )) l (( ))

Failed TIP Contribution to Bundle Power Due to I (( )) (( )) I (( )) I (( )) 1:

(( )) I (( )) I (( ))

Failed LPRM Total Uncertainty in Calculated I (( )) I (( )) I (( )) I (( )) I (( )) I (( )) I (( ))

Bundle Power Table 5. Power Distribution Uncertainties Page 25 of27

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Table 5. Power Distribution Uncertainties CprrEIIf Current' Cycle - Cycle Off-Rated -Power Rated Power Off-Rated Minimum Core'Flow Core Flow Limiting Limiting

• • Case Case Uncertainty of TIP Signal Nodal

(( )) (( )) (( )) (( )) (( )) (( )) (( ))

Uncertainty Table 5. Power Distribution Uncertainties Page 26 of27

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Table 6. Critical Power Uncertainties Previous -~ *, ! frevious i('*;1\~ent ~ ~:,~ Iw - ;;flil!l~*i, Cycle  :, ** Cycle . ., : ._;; Cycle Cy~le Rated Power ~ Rated P.ower

• O.U:Rpted Power Rated Power Minimum  ;. . Rated ~* :.c~ Off-Rated Minimum Core Flow Co~Flow Limiting Limiting Case Case rr

))

Table 6. Critical Power Uncertainties Page 27 of27

ATTACHMENT 6 Power/Flow Map for Cycle 21 with MELLLA+ Operating Domain

PBAPS Unit 2 Power to Flow Map with MELLLA+ Conditions Core Flow (Mlb!hr) 0 10 20 30 40 50 60 70 80 90 100 110 120 120 . . I; . . 4741 PailllS of Intan&t lrnoo/o a...TP

• 3951 MWt I l ft. Qnftowf-.1 ftDws"ftJiil I100% Core Flow - 102.5 Mlb hr I 110 --* ICF Increased Core flow Reoion 4346 A Natured Circulation B 30% Minimum Pum >Speed [IJ CT]_ ITJ D;J 100 -- c 38.0 54.9 ~

3951

~

D E

99.0 100.0 100.0 160.0 IMElllA+ Boundarv I / /

v 3556 90 .~

F 110.0 +oo.o *-

110.0 21.3

/

G H 100.0 21.3 I K / /

v 80 -~

I 37.4 21.3 -;----1 J

_,.,__~~.,..._ v .-._,._ .._~--,.-

3161 J 83.0 +oo.o

'# 70 -~

K L

55.0 55.0 78.8 68.4 yr Jtl ... / ',,._.,._ ..._.._ ___

• ~, ....----------*--- 2766 C'

I'

~

~

• 60

('/

I I A Rnt nrl;1rv I ---@}-* .,._...._.,._~--v.*~~-.-.._~w~~ .... - -

2370 e t

'"Cl Q

50

/to ,.,._.,._-~-,. w. * --*......_,.._,...,, ..,_ .... ,._ ~,.__.._,.w,_-~,-.~- .._ - ..... ,-.w -

1975

~

t

= 40 y.y ........... ,,_._..... ,. ........ _.,._.,._, _ _

1580 A? ((

30 . ----*- 1185 I J 20 790 I lJ u u

)  ;~ LJ !Cavitation IntErlo:k I_:

10 395

-~

~--- .J....,,.-..--*;**:"'"

..//

0 . 0 0 10 20 30 40 50 60 70 80 90 100 110 120 Core Flow (%)

Figure 1-1 Power/Flow Operating Map for MELLLA+