Text

License Amendment Request - Expanded Actions for LEFM Conditions
	ML18239A355
Person / Time
Site:	Peach Bottom
Issue date:	08/27/2018
From:	David Helker; Exelon Generation Co
To:	; Document Control Desk, Office of Nuclear Reactor Regulation
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ML18239A353	List: ML18239A355;
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	Download: ML18239A355 (170)
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200 Exelon Way Exelon Generation Kennett Square, PA 19348 www.exeloncorp.com PROPRIETARY INFORMATION -WITHHOLD UNDER 10 CFR 2.390 August 27, 2018 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Peach Bottom Atomic Power Stations, Units 2 and 3 Renewed Facility Operating License Nos. DPR-44 and DPR-56 NRC Docket Nos. 50-277 and 50-278 10 CFR 50.90 10 CFR 2.390

Subject:

License Amendment Request - Expanded Actions for LEFM Conditions

Reference:

(1) Exelon letter to the NRC, "Request for License Amendment Regarding Measurement Uncertainty Recapture Power Uprate," dated February 17, 2017 (ADAMS Accession No. ML17048A444)

(2) NRC letter to Exelon, "Peach Bottom Atomic Power Station, Units 2 and 3 -

Issuance of Amendments Re: Measurement Uncertainty Recapture Power Uprate," dated November 15, 2017(ML17286A013)

In accordance with 1 O CFR 50.90, "Application for amendment of license or construction permit," Exelon Generation Company, LLC (EGC) requests an amendment to Renewed Facility Operating License (RFOL) Nos. DPR-44 and DPR-56 for Peach Bottom Atomic Power Station (PBAPS), Units 2 and 3, respectively, for off-normal conditions of the Leading Edge Flow Meter (LEFM) ~ + (CheckPlus) system. The Measurement Uncertainty Recapture (MUR) License Amendment Request (LAR) (Reference 1) submitted by EGC for an increase in licensed thermal power based upon the improved accuracy of the LEFM CheckPlus system was approved by the NRC with the issuance of the Final Safety Evaluation Report and RFOL Amendments 316 and 319 for PBAPS Units 2 and 3, respectively (Reference 2).

The LEFM CheckPlus system has been operational at PBAPS since 2002. The MUR LAR, as approved by the NRC, specified the actions to be taken in the event that one or more LEFMs degraded from the CheckPlus (NORMAL) to the Check (MAINTENANCE) or FAIL mode.

Included among those approved actions was authorization to operate at a power level less than the maximum allowable licensed power but greater than pre-MUR level (referred to as an "Intermediate Power Level") when one or more of the LEFMs are in the Check mode. transmitted herewith contains Proprietary Information. When separated from Attachment 4, this document is decontrolled.

U.S. Nuclear Regulatory Commission Expanded Actions for LEFM Conditions August27,2018 Page2 The proposed change requested herein would expand the number of Intermediate Power Levels from one to four. Specifically, it would establish three separate Intermediate Power Levels for the LEFM CheckPlus system conditions in which one, two or three LEFMs are in Check mode, with none in FAIL mode. A fourth Intermediate Power Level would be for the LEFM condition in which the flow measurement input to the core thermal power calculation for one of the three feedwater lines is from the differential pressure Feedwater (FW) flow nozzle measurement (venturi) as a result of the associated LEFM being in the FAIL mode or otherwise not available for service. The Intermediate Power Levels correspond to the total power uncertainties conservatively calculated for each of the LEFM conditions. The LEFM system installation at PBAPS is unique in that some of the equipment is not accessible during power operation and a degraded LEFM could require a reactor outage to make repairs. This LAA would allow operation at power levels commensurate with the uncertainties in the measurement of core thermal power.

The proposed changes have been reviewed by the PBAPS Plant Operations Review Committee in accordance with the requirements of the EGC Quality Assurance Program.

EGC requests approval of the proposed changes by June 30, 2019.

In accordance with 1 O CFR 50.91, "Notice for public comment; State consultation,"

paragraph (b), EGC is notifying the Commonwealth of Pennsylvania and the State of Maryland of this application for license amendment by transmitting a copy of this letter and its attachments to the designated State Officials. contains an evaluation of the proposed changes including an assessment of how implementation will adhere to the principles of simple decision making for the operator and conservative plant operation. contains markups of the proposed Technical Requirements Manual Section 3.20 and the associated Bases (for information only), governing the maximum allowed power levels when any of the LEFMs are in other than the CheckPlus mode. provides the EGC PBAPS uncertainty calculation for the FW flow nozzle. provides the Cameron Total Power Uncertainty calculations for the three Check mode LEFM conditions. It also combines the FW flow nozzle uncertainty calculated in with the LEFM uncertainties to determine the Total Power Uncertainty when the flow measurement input for one feedwater line is from the FW flow nozzle. provides a proprietary version of the Cameron calculations, ER-464P, "Uncertainty Analysis for Thermal Power Determination at Peach Bottom Unit 2 Using the LEFM./+System," Revision 9, and ER-463P," Uncertainty Analysis for Thermal Power Determination at Peach Bottom Unit 3 Using the LEFM./ + System," Revision 8. Attachment 5 provides two affidavits executed by Cameron for withholding certain information contained in.

U.S. Nuclear Regulatory Commission Expanded Actions for LEFM Conditions August27,2018 Page 3 provides a non-proprietary version of Attachment 4. In accordance with 1 O CFR 2.390, "Public inspections, exemptions, requests for withholding," EGC requests withholding of Attachment 4.

Should you have any questions concerning this request, please contact Mr. David Neff at (267) 533-1132.

I declare under penalty of perjury that the foregoing is true and correct. Executed on the 271h day of August 2018.

Respectfully, David P. Helker Manager - Licensing & Regulatory Affairs Exelon Generation Company, LLC Attachments:

1. Evaluation of Proposed Changes

2. Markup of Proposed Technical Requirements Manual and Bases Pages (For Information Only)

3. Exelon Calculation PM-1209 Revision 0, "Peach Bottom Feedwater Flow Uncertainty as Measured in the Plant Computer as Measured by the Flow Nozzles Without Calibration by the LEFM"

4. Cameron ER-464P," Uncertainty Analysis for Thermal Power Determination at Peach Bottom Unit 2 Using the LEFM./+System," Revision 9 (Proprietary Version), and ER-463P," Uncertainty Analysis for Thermal Power Determination at Peach Bottom Unit 3 Using the LEFM./+System," Revision 8 (Proprietary Version)

5. Cameron Affidavit Supporting Withholding Attachment 4 from Public Disclosure

6. Cameron ER-464NP," Uncertainty Analysis for Thermal Power Determination at Peach Bottom Unit 2 Using the LEFM./+System," Revision 9 (Non-Proprietary Version), and ER-463NP," Uncertainty Analysis for Thermal Power Determination at Peach Bottom Unit 3 Using the LEFM./+System," Revision 8 (Non-Proprietary Version) cc:

USNRC Region I, Regional Administrator USNRC Senior Resident Inspector, PBAPS USNRC Project Manager, PBAPS A. A. Janati, Pennsylvania Bureau of Radiation Protection D. A. Tancabel, State of Maryland

License Amendment Request Expanded Actions for LEFM Conditions Page 1 of 20 Docket Nos. 50-277 and 50-278 Evaluation of Proposed Changes 1.0

SUMMARY

DESCRIPTION 2.0 DETAILED DESCRIPTION 2.1 PBAPS LEFM System 2.2 Current LEFM Compensatory Measures 2.3 Proposed Changes to the LEFM Compensatory Measures for LEFM in Check 2.4 Proposed Changes to the LEFM Compensatory Measures for One LEFM in Fail

3.0 TECHNICAL EVALUATION

3.1 Background

3.2 General Approach 3.3 Plant Implementation 3.4 Disposition of NRC Criteria for Use of LEFM Topical Reports 3.5 Deficiencies and Corrective Actions 3.6 Reactor Power Monitoring 4.0 ADDITIONAL CONSIDERATIONS 4.1 Plant Modifications 4.2 Operator Training, Human Factors, and Procedures 4.3 Testing

5.0 REGULATORY EVALUATION

5.1 Applicable Regulatory Requirements/Criteria 5.2 Precedent 5.3 No Significant Hazards Consideration 5.4 Conclusions

6.0 ENVIRONMENTAL CONSIDERATION

7.0 REFERENCES

License Amendment Request Expanded Actions for LEFM Conditions Page 2 of 20 Docket Nos. 50-277 and 50-278 Evaluation of Proposed Changes 1.0

SUMMARY

DESCRIPTION In February 2017, Exelon Generation Company, LLC (EGC) submitted a Measurement Uncertainty Recapture (MUR) License Amendment Request (LAR) (Reference 1) to revise the Operating License and Technical Specifications (TS) for the Peach Bottom Atomic Power Station (PBAPS) Renewed Facility Operating License (RFOL) Nos. DPR-44 and DPR-56. The 2017 MUR LAR resulted in an increase of 65 megawatts thermal (MWt, approximately 1.66% increase) in rated thermal power (RTP) from 3951 MWt to 4016 MWt. This request was based on the increased accuracy of the Cameron Holding Corporation (hereinafter Cameron) + (CheckPlus) Leading Edge Flow Meter (LEFM) ultrasonic feedwater flow measurement instrumentation relative to the feedwater (FW) flow nozzle differential pressure measurement (venturi or venturi meter) when used in the calculation of reactor core thermal power (CTP). The Cameron LEFM system has two operating modes (CheckPlus and Check); and an inoperable mode (Fail). The NRC issued a Safety Evaluation Report (SER) and approved the requested changes on November 15, 2017, with issuance of RFOL Amendments 316 and 319 for PBAPS Units 2 and 3, respectively (Reference 2). These amendments included authorization to operate at a power level of 4010 MWt after a Technical Requirements Manual (TRM)

Required Compensatory Measures Completion Time of 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months if one or more LEFMs remain in the Check mode and no LEFMs are in the Fail mode. Following successful power ascension testing, PBAPS Units 2 and 3 achieved the new licensed power level in January 2018.

The LEFM system has been the primary means of FW flow measurement since its installation following implementation of the initial MUR License Amendments 247 and 250 (Reference 3) in 2003. The licensing basis analyses performed for the Extended Power Uprate (EPU) license amendments received in 2014 (Reference 4) did not incorporate a MUR uprate using the improved accuracy of the LEFM system. Therefore, operation at EPU power levels did not include an MUR uprate or restrictions regarding the status of the LEFM system.

The NRCs Safety Evaluation of Cameron Topical Report ER-157P, Revision 8 (Reference 5) requires that, 1) for any single component failure to the LEFM CheckPlus system, continued operation at the pre-failure power level for a pre-determined time and

2) the decrease in core thermal power that must occur following the pre-determined time are plant-specific and must be justified. Accordingly, the 2017 MUR LAR provided the PBAPS plant-specific justification for 1) continued operation at the MUR uprate power level (i.e., 4016 MWt) for up to 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months after one, two or three LEFM(s) degraded to either the Check or the Fail mode and 2) to decrease power level to 4010 MWt if one or more LEFMs remain in the Check mode for greater than 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months and none are in Fail mode.

Since implementation of the MUR in 2018, the required compensatory measure if an LEFM changes from the CheckPlus to the Check or Fail mode or is otherwise taken out of service is to switch the FW flow input for the CTP calculation from the affected LEFM(s) to the associated FW lines nozzle within two hours. If any LEFM is in the Fail mode by the end of the TRM Required Compensatory Measures Completion Time, power must be reduced by 65 MWt to the pre-MUR licensed level of 3951 MWt.

License Amendment Request Expanded Actions for LEFM Conditions Page 3 of 20 Docket Nos. 50-277 and 50-278 Evaluation of Proposed Changes The LEFM acoustic transducers and cabling are located in the main steam tunnel where the radiation dose rate levels are elevated. This area is a Locked High Radiation Area and inaccessible during normal plant operation. If any of the LEFM components located in the steam tunnel cause the LEFM to be in Fail mode, reactor power is limited to 3951 MWt until the plant is shut down to identify and correct the problem. This installation configuration is unique to PBAPS. The standard LEFM acoustic transducer installation and associated LEFM system equipment is normally installed in plant areas that are accessible during power operations.

The current Maximum Allowable Power Level (MAPL) TRM limit of 4010 MWt when one or more LEFMs are in Check mode and none in Fail mode is based on the Cameron calculations in ER-464/463 Revision 5 (Attachment 1 of Reference 12) which assume that all three LEFMs are in Check mode. The compensatory measures and the intermediate power level for this condition were implemented by a revision to the TRM in January 2018.

This LAR provides the plant-specific analyses to support the proposed compensatory measures for operation of the LEFM system at three separate intermediate power levels for an indefinite period when the mass flow input to the CTP calculation is from one, two or three FW lines in Check mode with none in Fail mode; and a fourth intermediate power level when not more than one LEFM is in Fail mode and flow measurement is being provided by the associated FW flow nozzle. The proposed changes would allow operation at power levels commensurate with the uncertainties in the measurement of core thermal power and reduce the magnitude of the required reactivity maneuver and plant power level change for degradation of the LEFM system.

Since the proposed intermediate MAPL limits are based on total power uncertainties (TPUs) calculated at the same 95% confidence levels as the current MAPL limits, the probability of exceeding the thermal power level for which the Emergency Core Cooling Systems have been analyzed in accordance with 10 CFR 50, Appendix K, remains very low.

The LEFM flow measurement uncertainties are based on the same calculation methodology used to support the MUR LAR (Reference 1, Attachment 8 and Reference 12, Attachment 1). In this LAR, EGC is proposing that credit be taken for the lower uncertainties calculated for the condition when only one or two LEFMS are in the Check mode with none in Fail mode rather than considering that all are in Check mode.

Similarly, the calculation of the TPU for the condition in which one LEFM is in Fail mode is based on the LEFM Check mode uncertainties calculated for the MUR LAR combined with the FW flow nozzle uncertainty calculated for this LAR (Attachment 3).

The Cameron calculations supporting the LEFM FW flow uncertainties, which the four intermediate power levels are based upon, are provided in Attachment 4. The Cameron calculations use the methodology documented in NRC approved Cameron Topical Report ER-157P-A Revision 8 (Reference 5) and the PBAPS MUR Amendments 316 and 319 (Reference 2).

License Amendment Request Expanded Actions for LEFM Conditions Page 4 of 20 Docket Nos. 50-277 and 50-278 Evaluation of Proposed Changes The calculation for the uncertainty associated with the measurement of FW flow by the FW flow nozzle is provided in Attachment 3 and is based on the instrument setpoint uncertainty calculation methodology described in American Society of Mechanical Engineers (ASME) PTC 6 Report (Reference 11).

The TPU for each of the LEFM operating conditions is determined using the square-root-sum-of-squares (SRSS) approach which is the industry accepted method for combining instrument accuracies. The MAPL for each of the four proposed intermediate LEFM operating conditions is then determined by the following equation:

MAPL 4030 MWt / (1+), where 4030 MWt is 102% of pre-MUR licensed power level of 3951 MWt and

= TPU for a particular condition The proposed compensatory measures and intermediate power levels differ from those approved by the NRCs SER for the MUR LAR, although the LEFM uncertainty and TPUs supporting this LAR are consistent with Cameron Topical Report ER-157P-A Revision 8 (Reference 5). The topical report, however, did not consider using the uncertainty associated with FW flow nozzle as an input to a TPU calculation. EGC therefore concluded that NRC pre-approval in the form of a license amendment is required.

2.0 DETAILED DESCRIPTION The changes to the MAPLs associated with each of the LEFM conditions are described in Section 2.2. If approved, they will be incorporated into a revision to TRM Section 3.20 as shown by the marked-up pages provided in Attachment 2. No changes are required to the Operating Licenses or to the TS by this LAR.

2.1 PBAPS LEFM System The PBAPS LEFM System consists of three LEFMs, one on each of the three FW lines.

Each LEFM contains two independent subsystems or planes with each plane containing four acoustic paths. The LEFM system has two operating modes (CheckPlus and Check) and an inoperable mode (Fail). In the CheckPlus mode (also described in this LAR as the Normal mode), both planes of transducers are in service. If an LEFM is subjected to a failure involving a transducer on one plane of operation, that LEFM reverts to the Check mode (also described in this LAR as the Maintenance mode). The flow data from an LEFM with a single functioning plane (Check mode) has greater associated measurement uncertainty than that from an LEFM with both planes functioning, but less associated measurement uncertainty than that from a FW flow nozzle.

Conditions for operation, required actions, and completion times for the LEFM system are currently contained in TRM Section 3.20, Leading Edge Flow Meter (LEFM) System. In accordance with PBAPS Updated Final Safety Analysis Report (UFSAR), Section 13.6.8, Requirements Relocated Out of Technical Specifications, the TRM is a licensee-controlled procedure described in the UFSAR and therefore, changes to the TRM are subject to the requirements of 10 CFR 50.59, Changes, tests, and experiments. As such, changes to the LEFM TRM are controlled under the provisions of 10 CFR 50.59.

License Amendment Request Expanded Actions for LEFM Conditions Page 5 of 20 Docket Nos. 50-277 and 50-278 Evaluation of Proposed Changes 2.2 Current LEFM Compensatory Measures The LEFM status is determined and reported by the LEFM System computer based upon the number of functional planes in the LEFM and the data quality. If one or more LEFMs go into the Check mode with none in Fail mode, operators must switch flow input to the CTP calculation from the LEFM(s) that are not in CheckPlus mode to the associated calibrated FW flow nozzle within two hours. By the end of the 72-hour TRM Required Compensatory Measures Completion Time, either all LEFMs must be restored to the CheckPlus mode with all flow input to the CTP calculation from the LEFMs or MAPL must be reduced to 4010 MWt.

If one or more LEFM FW flow nozzle(s) reverts to the Fail mode or is not providing flow input to the CTP calculation, flow measurement from that FW line must be transferred to its calibrated FW flow nozzle within two hours. A FW flow nozzle is considered calibrated when a venturi correction factor (VCF) is applied to the FW flow nozzle measurement in accordance with station procedures. The VCF is the ratio of the flow measurement from the LEFM in CheckPlus mode to that of the associated FW flow nozzle. Under the current requirements, power must then be reduced to the pre-MUR level of 3951 MWt before the end of the 72-hour TRM Required Compensatory Measures Completion Time if all of the LEFMs have not been restored to either the CheckPlus or Check mode.

If an LEFM changes to a status other than CheckPlus after a TRM condition has been entered for that LEFM (i.e., mode status changes from Check to Fail or Fail to Check),

then the completion times for the new required compensatory measures of the applicable TRM condition(s) must be completed based on a start time corresponding to initial entry into the TRM condition.

As stated above, repair of an LEFM that degrades to the Maintenance or Fail mode may have to be delayed until the next refueling outage or require an unscheduled plant shutdown due to the high radiation levels during power operation in the vicinity of the spool pieces containing the flow measurement transducers and cabling.

2.3 Proposed Changes to the LEFM Compensatory Measures for LEFMs in Check The proposed changes would expand the number of intermediate power levels from one to four. The intermediate power levels correspond to the total power uncertainties (TPUs) conservatively calculated for each of the LEFM system meter conditions. The existing LEFM System TRM Section 3.20 would be revised to include the proposed changes to the Conditions, Required Compensatory Measures and Completion Times. Except for the specific LEFM condition and the interim power levels, the TRM actions and completion times are the same as currently contained in the NRC approved TRM. The LEFM status and proposed maximum interim power levels are described below:

1. Three separate intermediate power levels for the LEFM system meter conditions in which one, two, or three LEFMs are in Maintenance mode, with none in Fail mode.

2. A fourth intermediate power level is for one LEFM in the Fail mode with the other two LEFMs in Normal or Maintenance mode. The FW line FW flow nozzle is then used for the LEFM in Fail mode as the input to the core thermal power calculation.

License Amendment Request Expanded Actions for LEFM Conditions Page 6 of 20 Docket Nos. 50-277 and 50-278 Evaluation of Proposed Changes 2.4 Proposed Changes to the LEFM Compensatory Measures for One LEFM in Fail As with the current LEFM TRM Section 3.20 Required Compensatory Measures and Completion Times, the proposed changes in this LAR require that the FW flow signal from an LEFM that changes from CheckPlus to Check or Fail mode be switched to its associated calibrated FW flow nozzle within two hours.

As with the current LEFM TRM Section 3.20 Required Compensatory Measures and Completion Times, the proposed changes in this LAR require that, when one or more LEFMs are in Check mode with none in Fail mode by the end of the TRM Required Compensatory Measures Completion Time, flow input to the CTP calculation must be switched back to the LEFM and power reduced to the prescribed MAPL. For this LAR, two interim power levels are proposed for one and two LEFMs in the Check Mode based on the TPU for that condition as shown in the table below.

If one LEFM goes into Fail mode or is otherwise not providing flow input to the CTP calculation, and has not been restored to CheckPlus or Check mode by the end of the TRM Required Compensatory Measures Completion Time, power must be reduced to the MAPL commensurate with the TPU for the one LEFM in Fail mode condition shown in the table. If the affected LEFM is restored to the Check mode, power must be reduced to the MAPL appropriate to the LEFM operating condition (i.e., one, two, or three in Check mode with none in Fail mode) shown in the table below.

If this LAR is approved, the MAPLs for the various LEFM operating conditions shown in the table below will be incorporated into a revision to TRM Section 3.20 as provided in.

License Amendment Request Expanded Actions for LEFM Conditions Page 7 of 20 Docket Nos. 50-277 and 50-278 Evaluation of Proposed Changes LEFM OPERATING CONDITION TPU MAPL (MWt)

Existing or New TRM Condition All LEFMs in CheckPlus mode 0.34%

4016 Existing One LEFM in Check mode; none in Fail mode 0.37%

4015 New Two LEFMs in Check mode; none in Fail mode 0.43%

4012 New Three LEFMs in Check mode 0.51%

4009 New One LEFM in Fail mode with the other two LEFMs in CheckPlus or Check mode, flow measurement by associated FW flow nozzle 1.19%

3982 New Two or three LEFMs in Fail mode 2%1 3951 Existing

3.0 TECHNICAL EVALUATION

3.1 Background

PBAPS Units 2 and 3 have received the following license amendments authorizing increases in licensed CTP:

In 1994 and 1995, Amendments 198 and 211 to the Units 2 and 3 operating licenses, respectively, authorized a stretch power uprate of 5% from OLTP of 3293 MWt to 3458 MWt In 2002, Amendments 247 and 250 to the Units 2 and 3 operating licenses, respectively, authorized an MUR uprate from 3458 MWt to 3514 MWt based on the reduced uncertainty in feedwater flow measurement using the installed LEFM systems (Reference 3).

In 2014, Amendments 293 and 296 to the Units 2 and 3 RFOLs authorized an EPU increasing power from 3514 MWt to 3951 MWt (Reference 4).

In 2017, Amendments 316 and 319 to the Units 2 and 3 RFOLs, respectively, authorized an MUR uprate from 3951 MWt to 4016 MWt based on the reduced uncertainty in feedwater flow measurement using the installed LEFM systems (Reference 2).

1 To comply with 10 CFR 50 Appendix K analysis.

License Amendment Request Expanded Actions for LEFM Conditions Page 8 of 20 Docket Nos. 50-277 and 50-278 Evaluation of Proposed Changes 3.2 General Approach The uncertainties associated with the LEFM operating conditions shown above are calculated as follows:

The uncertainty calculated for the condition in which feedwater flow on one of the three feedwater lines is being measured by the FW flow nozzle conservatively assumes that the LEFMs on the other two feedwater lines are in Check mode.

Calculation of the feedwater mass flow uncertainty for a line being measured by the FW flow nozzle assumes that the instrument loop has not been calibrated by the LEFM (i.e., VCF = 1.000).

The methodology used to calculate the loop uncertainty for the FW flow nozzle is based on EGC-accepted PBAPS plant setpoint methodology. In accordance with this methodology, independent error terms are combined via square root sum of the squares (SRSS) and taken to 2 or a 95% confidence level. Dependent errors are combined according to their dependency relationships and the biases algebraically summed. ASME PTC-6 (Reference 11) is used to determine the error in the FW flow nozzles because it provides a conservative means to quantify the FW flow nozzle uncertainties, and it takes into account the upstream and downstream flow disturbances due to piping configurations.

The methodology for the calculation of the feedwater mass flow uncertainty as measured by an LEFM in Check mode is the same as that performed for the MUR LAR (Reference 1) and is consistent with the methodology of Cameron Topical Report ER-157P-A Revision 8 (Reference 5).

Where PBAPS Units 2 and 3 plant specific data is used, the most conservative value from each Unit is used in the Uncertainty Analysis for thermal power determination.

The total feedwater mass flow uncertainty is calculated by combining the results for the LEFM and the FW flow nozzle uncertainties as appropriate for each LEFM operating condition using SRSS methodology consistent with ER-157P-A Revision 8.

The TPU for each LEFM operating condition is calculated by combining the feedwater mass flow uncertainty with other plant specific terms (steam enthalpy, moisture carryover, etc.) using SRSS methodology consistent with ER-157P-A Revision 8.

The TPU calculation (Attachment 4) differs from the methodology described in Cameron Topical Report ER-157P-A Revision 8 (Reference 5) only for the LEFM operating condition in which the flow input to the CTP for one of the FW lines is being measured by the FW flow nozzle.

The inputs and assumptions for the TPU calculation for the LEFM System condition of three LEFMs in the Check Mode are the same as those used in the TPU calculation for the MUR LAR submitted in 2017 (Reference 1, Attachment 8, Appendix B-1), except for the Time Measurement, Item 8, Non-Fluid Delay (Refer to this LAR Attachment 4, Appendix B-2). This uncertainty parameter increased slightly (i.e., from 0.50% to 0.51%)

due to a change that corrected an error in the previous revision of the uncertainty

License Amendment Request Expanded Actions for LEFM Conditions Page 9 of 20 Docket Nos. 50-277 and 50-278 Evaluation of Proposed Changes calculation. The total uncertainty in the time spent by ultrasonic pulses in a non-fluid media for a single meter is made up of a random component and a systematic component that are root sum squared together (Refer to Reference 1 Attachment 8 Appendix A.5 and this LAR Attachment 4, Appendix A.5). When calculating the impact across multiple meters, the random portion of the term is divided by the square root of the number of meters (i.e., for PBAPS = sqrt(3)) because not only is it random within the meter, but also between meters. The effect of the systematic term though cannot be decreased in this manner and should remain constant even when considering multiple loops. The earlier LEFM calculation (Reference 1 Attachment 8, Appendix B-1) combined both the random and systematic terms and then divided that value by the sqrt(3) incorrectly. This has been corrected in the calculations provided in this LAR (Attachment 4, Appendix B-2).

Using the corrected Time Measurement values and the resulting TPU for three LEFMs in Check mode, the MAPL limit for TRM Required Compensatory Measure calculated value slightly decreased and due to rounding for conservatism, the proposed TRM MAPL limit is lowered from 4010 MWt to 4009 MWt. The Time Measurement parameter change is also used in the TPU calculations for the other LEFM system conditions described in this LAR. This correction was evaluated for impact on current LEFM TRM Required Compensatory Measure actions and appropriate corrective actions have been taken.

3.3 Plant Implementation The revised compensatory measures will be incorporated into the existing TRM Section 3.20. Only minor changes to other existing procedures will be required. A description of the impact of the implementation of the proposed change with respect to operator decision making and conservative plant operation is provided in Section 3.4 Criterion 1 below.

3.4 Disposition of NRC Criteria for Use of LEFM Topical Reports to the MUR LAR (Reference 1) described how the nine criteria established by the NRC in References 7, 8 and 9 for licensees incorporating the LEFM methodology into the licensing basis are satisfied. The NRC approved this request in Amendments 316 and 319 (Reference 2) and specifically discussed in SER Section 3.5.4, Thermal Power Measurement Uncertainty. The paragraphs below confirm or update the disposition of these criteria at PBAPS as necessary for LEFM system conditions in which either one, two, or three LEFMs are in Check mode; and for the condition in which the FW flow input from one FW line to the CTP calculation is based on the associated FW flow nozzle.

Criterion 1 Discuss maintenance and calibration procedures that will be implemented with the incorporation of the LEFM, including processes and contingencies for inoperable LEFM instrumentation and the effect on thermal power measurements and plant operation.

License Amendment Request Expanded Actions for LEFM Conditions Page 10 of 20 Docket Nos. 50-277 and 50-278 Evaluation of Proposed Changes Response to Criterion 1 Calibration and Maintenance The proposed changes will not affect the calibration and maintenance procedures as described in the MUR LAR (Reference 1) for the LEFM system.

With respect to flow measurement by the FW flow nozzle, existing procedures require the calibration of the FW flow nozzle instrument loop every refueling outage. If measurement of FW flow is transferred from an LEFM to the FW flow nozzle, VCF is applied to the FW flow nozzle measurement. The VCF is based on inputs obtained within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months from the time that the LEFM went into Check or Fail mode, or was otherwise removed from service. Operators in the main control room can assess the VCF displayed value which is updated continuously on the Plant Monitoring System (PMS) display. PBAPS Engineering performs a periodic comparison of the VCF value to established trends.

These measures will ensure the accuracy of the CTP calculation while relying on feedwater flow measurement from the FW flow nozzle.

LEFM Inoperability The disposition of Criterion 1, LEFM Inoperability contained in the MUR LAR is not changed by this LAR with the exception of the discussion of TRM Section 3.20 (5th paragraph of corresponding section in the MUR LAR) which is replaced by the discussion below.

As described in the following sections, the proposed changes to the compensatory measures requested in this LAR are consistent with the principles of simple decision making on the part of the control room operator and conservative plant operation.

Simple Decision Making The range of decisions and actions facing the operator will not be fundamentally different or made more complex by the proposed changes than those on which PBAPS operators have been trained on and implemented since the LEFM system was commissioned in 2002. On-line, continuous monitoring of system parameters generates PMS alarms in the control room that immediately alert the operator to a change in status of an LEFM.

The operators then execute existing procedure steps to calibrate the FW flow nozzle and switch the CTP calculation input to the FW flow nozzle. Then, if the LEFM is not restored to NORMAL status, the operators must reduce power by 1 to 34 MWt, depending on the LEFM malfunction, by lowering reactor recirculation flow within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months of the initial failure. Additionally, for an LEFM retained in the Maintenance mode, operators must re-align the associated FW flow nozzle measurement input to the plant CTP calculation back to the LEFM by the end of the 72-hour TRM Completion Time period using similar PMS computer input actions.

If for some reason it is not possible to calibrate the FW flow nozzle to its associated LEFM (e.g., a valid Venturi Correction Factor cannot be obtained), the proposed Required Compensatory Measures B.1.1, D.1.1, and F.1 require that power be reduced to a level supported by the uncertainty analysis after two hours. These power levels are specified in TRM Table 3.20-1 for LEFM(s) in the Check mode, or directly in the Compensatory Measures for an LEFM in the Fail mode. Operators would reduce reactor

License Amendment Request Expanded Actions for LEFM Conditions Page 11 of 20 Docket Nos. 50-277 and 50-278 Evaluation of Proposed Changes power by lowering reactor recirculation flow using existing reactor power control procedure actions. Operator actions per this TRM are consistent with existing TS actions.

There are no new alarms or operator actions and no changes to operator response times introduced due to this TRM change. A minor revision to existing operating procedures will be made to reflect the new intermediate power levels. Swapping CTP inputs between the LEFM and the FW flow nozzle is a task performed several times a year using a procedure that has been in place since the installation of the LEFMs in 2002.

Because the proposed revision to TRM 3.20 has only a minor impact on existing operating procedures by adding intermediate power levels for when LEFM(s) enter non-Normal statuses, the revision will only have a minor impact on human factors in the areas of human performance and operator training. No additional training (apart from normal training for plant procedure changes) is required to operate the plant due to this TRM revision. The actions for communicating the TRM and procedure changes to the operators will be tracked using the existing Exelon configuration change control process.

A Human Factors Engineering (HFE) evaluation was performed using the guidance in NUREG 1764, Guidance for the Review of Changes to Human Actions, Revision 1. The HFE determined the following key conclusions:

Operator actions as they relate to monitoring reactor power via the calorimetric heat balance are not risk significant.

All operator actions including monitoring, adjusting CTP input parameters, and reducing power as required, have a high probability of success and do not result in the likelihood of undiscovered failures.

None of the operator actions required by the proposed change are included in Appendix A of NUREG-1764 Revision 1 as Generic Human Actions that are Risk-Important for BWRs.

The proposal does not change operator actions on systems that are of high or moderate risk-importance.

No changes are involved with the proposed LAR that would require additional reviews for Personnel Functions and Tasks, Design Support for Task Performance or Performance Shaping Factors.

The proposed TRM change only needs a Level III HFE review.

The control room operator therefore faces a simple set of criteria in deciding what actions to take for an inoperable LEFM, has adequate time to take such actions, and will use existing procedures that have been in place for a substantial period of time.

License Amendment Request Expanded Actions for LEFM Conditions Page 12 of 20 Docket Nos. 50-277 and 50-278 Evaluation of Proposed Changes Conservative plant operation Conservative plant operation under the new proposed compensatory measures starts with the calculations of the LEFM, FW flow nozzle and total power uncertainties on which the proposed changes to the LEFM system compensatory measures are based. Use of NRC-approved and industry-accepted methodologies and conservative assumptions will provide margin to ensure that the plants will not operate above the licensed thermal power. Plant monitoring instrumentation and procedures will verify that the assumptions underlying the uncertainty calculations remain valid.

The calculations of LEFM uncertainty use the same methodology as in the MUR LAR and are consistent with ER-157P-A Revision 8. Since there is some variation in the calculated LEFM uncertainties for each unit, the uncertainty values from the most limiting meter are applied to all of the LEFM meters. Another element of the conservatism in the LEFM uncertainty calculation is in the assumption made for plane balance variability (PBV). Plane balance refers to the ratio of the FW flow velocities as measured by each of the two planes of transducers in an LEFM CheckPlus system. Uncentered vortex and axial motions known as swirl can cause cross velocities which affect the accuracy of the measurement of feedwater mass flow from each plane and thereby change the plane balance. When operating in the CheckPlus mode, the LEFM flow measurement system will, by design, cancel out the cross velocities impacting each plane and they therefore do not contribute uncertainty to flow measurement. However, during operation in the Check mode, with only one plane of transducers, the uncancelled cross velocities must be considered in the determination of the LEFM uncertainty. Although recent plant-specific operating data indicates an uncertainty attributed to PBV of only 0.19% at a 2 confidence level, the LEFM uncertainty calculations supporting this LAR (Attachment 4) which, as stated above are the same as those approved by the NRC for the MUR LAR, apply a PBV uncertainty of 0.35%.

The calculation of the flow measurement error for the FW flow nozzle (Attachment 3) uses the ASME PTC-6 Report 1985 (Reference 11) methodology to determine the error in the FW flow nozzle, including upstream and downstream disturbances. FW flow nozzle instrument loop uncertainty is based on EGC setpoint methodology in which independent error terms are combined via SRSS and taken to a 2 or a 95% confidence level, and dependent errors are combined according to their dependency relationships and biases algebraically summed. The calculation for FW mass flow uncertainty as measured by the FW flow nozzle also assumes that it has not been calibrated to its associated LEFM which assumes a conservative uncertainty as further discussed below.

The TPU calculations which combine the LEFM and FW flow nozzle measurement uncertainties for each of the four intermediate MAPL limits also account for other plant-specific terms along with the FW mass flow uncertainty and combine these terms using SRSS methodology of ASME PTC 19.1 (Reference 10) consistent with ER-157P-A Revision 8.

The accuracy of CTP measurement with flow input from one FW flow nozzle can be maintained indefinitely, if necessary. The feedwater flow process is calibrated every refueling outage. Changes in FW flow nozzle differential pressure for a particular flow are usually due to fouling or erosion which occur over long periods. LEFM to FW flow nozzle measurement ratios are constantly updated in the plant process computer and nightly checks are made to ensure predetermined limits are not exceeded. Any slight drift of the FW flow nozzle measurements while operating at the proposed new intermediate point

License Amendment Request Expanded Actions for LEFM Conditions Page 13 of 20 Docket Nos. 50-277 and 50-278 Evaluation of Proposed Changes due to FW flow nozzle fouling would result in a higher than actual indication of feedwater flow and an overestimation of the calculated calorimetric power level. A sudden de-fouling event while on the FW flow nozzle is unlikely and any significant sudden de-fouling would be detected by other plant parameters.

Criterion 2 For plants that currently have LEFMs installed, provide an evaluation of the operational and maintenance history of the installed installation and confirmation that the installed instrumentation is representative of the LEFM system and bounds the analysis and assumptions set forth in Topical Report ER-80P.

Response to Criterion 2 As stated in the MUR LAR, the PBAPS LEFM system installed instrumentation is representative of and bounded by the analysis and assumptions set forth in Topical Report ER-80P (Reference 6).

A review of the maintenance history of the LEFM system since January 2011 indicates the LEFM system continues to be highly reliable. During the period, no LEFMs were in the Fail mode. The LEFM system continued to be used for the FW flow measurement input but the improved uncertainty was not used between implementation of the EPU and MUR amendments. TRM actions for degraded LEFMs were re-instituted with implementation of the MUR amendment in January 2018. Since implementation of the MUR amendments, there were no instances on Unit 3 and one instance on Unit 2 when an LEFM was in the Check mode requiring MAPL reduction. In this instance, Unit 2 power was reduced to 4010 MWt in accordance with the TRM requirements. The Unit 2, Meter 1 transducer coupling has become degraded and has resulted in this LEFM entering the Check mode several times for short periods of time. A forced outage is required to troubleshoot and repair this LEFM.

EGC continues to follow an LEFM system preventive maintenance program based on vendor recommendations, industry lessons learned and performance data reviews.

Transducers and LEFM electronics are replaced as determined to be necessary by a review of the equipments operational history by the LEFM system vendor.

Criterion 3 Confirm that the methodology used to calculate the uncertainty of the LEFM in comparison to the current feedwater instrumentation is based on the accepted plant setpoint methodology (with regard to the development of instrument uncertainty). If an alternative approach is used, the application should be justified and applied to both venturi and ultrasonic flow measurement instrumentation installations for comparison.

Response to Criterion 3 The LEFM system uncertainty calculation methodology continues to be based on EGC-accepted PBAPS plant setpoint methodology as described in Attachment 1 to the MUR LAR. The calculation of the FW flow nozzle uncertainty is also based on EGC-accepted PBAPS plant setpoint methodology.

License Amendment Request Expanded Actions for LEFM Conditions Page 14 of 20 Docket Nos. 50-277 and 50-278 Evaluation of Proposed Changes The methodology for combining the FW flow nozzle and LEFM uncertainties to determine the total mass flow uncertainty, and then combining this with other plant-specific parameters (steam enthalpy, moisture carry-over, etc.) to calculate the TPU is based on the methodology described in the ASME PTC 19.1 methodology (Reference 10).

Criterion 4 For plants where the ultrasonic meter (including LEFM) was not installed with flow elements calibrated to a site-specific piping configuration (i.e., flow profiles and meter factors not representative of the plant specific installation), additional justification should be provided for its use. The justification should show that the meter installation is either independent of the plant specific flow profile for the stated accuracy, or that the installation can be shown to be equivalent to known calibrations and plant configurations for the specific installation including the propagation of flow profile effects at higher Reynolds numbers. Additionally, for previously installed calibrated elements, confirm that the piping configuration remains bounding for the original LEFM installation and calibration assumptions.

Response to Criterion 4 Disposition of this Criterion is not changed by this LAR from that provided in Attachment 1 to the MUR LAR as reviewed and approved by the NRC.

Criterion 5 Justification for continued operation at the pre-failure level for a pre-determined time and the decrease in power that must occur following that time are plant-specific and must be acceptably justified.

Response to Criterion 5 Justification for continued operation at 4016 MWt for up to 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months with one or more LEFMs either in Fail or in Check mode is not changed from that provided in Attachment 1 to the MUR LAR as reviewed and approved by the NRC.

Justification for the required decreases in power by the end of the TRM Required Compensatory Measures Completion Time for each of the proposed intermediate LEFM conditions is provided in the response to Criterion 1 above.

Criterion 6 A CheckPlus operating with a single failure is not the same as an LEFM Check. Although the effect on hydraulic behavior is expected to be negligible, this must be acceptably quantified if a licensee wishes to operate using the degraded CheckPlus at a degraded uncertainty.

Response to Criterion 6 Disposition of this Criterion is not changed by this LAR from that provided in Attachment 1 to the MUR LAR as reviewed and approved by the NRC (Reference 2).

Criterion 7 An applicant with a comparable geometry can reference the above Section 3.2.1 finding

[of the Final NRC Safety Evaluation for Caldon Topical Report ER-157P Rev 8] to support a conclusion that downstream geometry does not have a significant influence on CheckPlus calibration. However, CheckPlus results do not apply to a Check and downstream effects with use of a CheckPlus with disabled components that make the

License Amendment Request Expanded Actions for LEFM Conditions Page 15 of 20 Docket Nos. 50-277 and 50-278 Evaluation of Proposed Changes CheckPlus comparable to a Check must be addressed. An acceptable method is to conduct applicable Alden Laboratory tests.

Response to Criterion 7 Disposition of this Criterion is not changed by this LAR from that provided in Attachment 1 to the MUR LAR as reviewed and approved by the NRC (Reference 2).

Criterion 8 An applicant that requests an MUR with the upstream flow straightener configuration discussed in Section 3.2.2 [of the Final NRC Safety Evaluation for Caldon Topical Report ER-157P Rev 8] should provide justification for claimed CheckPlus uncertainty that extends the justification provided in Reference 17. Since the Reference 17 evaluation does not apply to the Check, a comparable evaluation must be accomplished if a Check is to be installed downstream of a tubular flow straightener.

Response to Criterion 8 Disposition of this Criterion is not changed by this LAR from that provided in Attachment 1 to the MUR LAR as reviewed and approved by the NRC (Reference 2).

Criterion 9 An applicant assuming large uncertainties in steam moisture content should have an engineering basis for the distribution of uncertainties or, alternatively, should ensure that their calculations provide margin sufficient to cover the differences shown in Figure 1 of Reference 18.

Response to Criterion 9 Disposition of this Criterion is not changed by this LAR from that provided in Attachment 1 to the MUR LAR as reviewed and approved by the NRC (Reference 2).

3.5 Deficiencies and Corrective Actions The handling of any problems, performance or reliability issues with the LEFMs as reported in the MUR LAR is not changed by this LAR. Problems with plant instrumentation, including the LEFM system and FW flow nozzles are documented in the PBAPS corrective action program and necessary corrective actions are identified and implemented. Deficiencies associated with the vendors processes or equipment are reported to the vendor to support corrective action.

3.6 Reactor Power Monitoring PBAPS Unit 2 and Unit 3 have procedures that provide guidance for monitoring and controlling reactor power and ensuring that reactor power remains within the requirements of the operating license.

4.0 ADDITIONAL CONSIDERATIONS 4.1 Plant Modifications No plant modifications are required.

4.2 Operator Training, Human Factors, and Procedures

License Amendment Request Expanded Actions for LEFM Conditions Page 16 of 20 Docket Nos. 50-277 and 50-278 Evaluation of Proposed Changes Implementation of this LAR would only have a minor impact on human factors in the areas of operating procedure changes, operator training and operator human performance. Existing procedures will be modified to reflect the revised TRM Section 3.20 (Attachment 2). There are no changes to the control room, indications, alarms, computer displays or the simulator necessary to implement this LAR. Operators will be trained on implementation of the revised TRM Section 3.20 requirements in accordance with the PBAPS Licensed Operator Training program before implementation. The actions for communicating the TRM and procedure changes to the operators will be tracked using the existing EGC configuration change control process.

As discussed in Section 3.4 under Criterion 1, the proposed change will not impose any complex decision making requirements on the operators and only Level III HFE review is warranted.

4.3 Testing No additional testing is necessary for implementation of this LAR.

5.0 REGULATORY EVALUATION

5.1 Applicable Regulatory Requirements/Criteria 10 CFR 50, Appendix K, ECCS Evaluation Models, requires that emergency core cooling system evaluation models assume that the reactor has been operating continuously at a power level at least 1.02 times the licensed power level to allow for instrumentation error. A change to this paragraph, which became effective on July 1, 2000, allows a lower assumed power level, provided the proposed value has been demonstrated to account for uncertainties due to power level instrumentation error.

The NRC issued a safety evaluation report (Reference 2) on the license amendment request (LAR) submitted by Exelon Generating Company, LLC (EGC) for a Measurement Uncertainty Recapture Power Uprate (Reference 1) and amended the PBAPS Units 2 and 3 operating licenses to allow an increase in maximum licensed thermal power based on a lower calculated uncertainty associated with the measurement of the feedwater flow input to the core thermal power (CTP) calculation from the LEFM system.

This application for a LAR approval is for a change to the compensatory measures for degraded LEFM conditions. The proposed changes would allow operation at power levels commensurate with the uncertainties in the measurement of CTP as calculated in Attachments 3 and 4 for conditions in which the flow from either one, two or three feedwater (FW) lines is being measured by LEFMs that have degraded from the CheckPlus to the Check mode with none in Fail mode as well as when one LEFM is in Fail mode or not providing flow input to CTP, with flow measurement provided by the associated FW flow nozzle.

This application is consistent with the requirements and criteria described in 10 CFR 50, Appendix K and 10 CFR 50.90.

License Amendment Request Expanded Actions for LEFM Conditions Page 17 of 20 Docket Nos. 50-277 and 50-278 Evaluation of Proposed Changes 5.2 Precedent The NRC has approved an intermediate power level for a Check (Maintenance) mode for the following plants:

PLANT LAR Accession No.

NRC SER Accession No.

PBAPS 2&3 ML17048A444 ML17286A013 Columbia ML16183A365 ML17095A117 Turkey Point 3&4 ML103610319 ML11293A359 St. Lucie 1 ML103560429 ML12191A220 St. Lucie 2 ML110730341 ML12235A463 Shearon Harris ML11356A096 ML11124A180 Prairie Island ML093650061 ML102030573 In the Turkey Point and St. Lucie 1 and 2 safety evaluation reports, the NRC discussed simple decision making and conservative plant operation in the evaluation of the MUR requests. The PBAPS demonstration of compliance with these criteria is provided above in Section 3.4 in the response to Criterion 1.

5.3 No Significant Hazards Consideration The NRC approved a license amendment request (LAR) by Exelon Generation Company, LLC (EGC) for a Measurement Uncertainty Recapture Power Uprate (Reference 1) and authorized an increase of 65 megawatts in maximum licensed thermal power from 3951 megawatts thermal (MWt) to 4016 MWt in Amendments 316 and 319 to the Peach Bottom Atomic Power Station (PBAPS) Unit 2 and Unit 3 Renewed Facility Operating License (RFOL), respectively. The approved license amendments were based on the increased accuracy of the Cameron Holding Corporation (hereinafter Cameron) +

(CheckPlus) Leading Edge Flow Meter (LEFM) ultrasonic flow measurement instrumentation relative to the feedwater (FW) flow nozzle (venturi meter) differential pressure measurement installed at PBAPS in the calculation of core thermal power (CTP).

In accordance with 10 CFR 50.90, Application for Amendment of License, Construction Permit, or Early Site Permit, EGC is proposing that RFOL Nos. DPR 44 and DPR-56 for PBAPS Units 2 and 3, respectively, be amended to allow operation at power levels based on the uncertainties calculated for the measurement of CTP when either one, two or three LEFMs are operable but in a degraded condition (Check mode) with none inoperable; and when one LEFM is inoperable (Fail mode) or the flow input to the CTP calculation for one of the FW lines is from the associated FW flow nozzle. EGC has evaluated whether a significant hazards consideration is involved with the proposed changes in accordance with the three standards set forth in 10 CFR 50.92, Issuance of Amendment, as discussed below.

1.

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

License Amendment Request Expanded Actions for LEFM Conditions Page 18 of 20 Docket Nos. 50-277 and 50-278 Evaluation of Proposed Changes Response: No, the proposed change does not significantly increase the probability or consequences of an accident previously evaluated.

The proposed change does not affect system design or operation and thus does not create any new accident initiators or increase the probability of an accident previously evaluated. Accident mitigation systems are not affected and will function as designed.

The proposed change does not increase the licensed thermal power level and will not cause the thermal power level at which the Emergency Core Cooling Systems have been analyzed in accordance with Appendix K to 10 CFR 50 to be exceeded. All safety analyses continue to be bounded by the safety analyses for the current licensed thermal power.

Therefore, the proposed change does not involve a significant increase in the probability or consequences of an accident previously evaluated.

2.

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

Response: No, the proposed change does not create the possibility of a new or different kind of accident from any accident previously evaluated.

No new accident scenarios, failure mechanisms, or limiting single failures are introduced as a result of operation at power levels based on the uncertainties in the calculation of CTP for the stated LEFM system conditions. Calculation of the uncertainty associated with these plant conditions as well as existing plant instrumentation and procedures ensure that the licensed thermal power and the thermal power level at which the Emergency Core Cooling Systems have been analyzed in accordance with Appendix K to 10 CFR 50 will not be exceeded. No new equipment or procedure changes are involved that could add new accident initiators.

Therefore, the proposed change does not create the possibility of a new or different kind of accident from any accident previously evaluated.

3.

Does the proposed change involve a significant reduction in a margin of safety?

Response: No, the proposed change does not involve a significant reduction in a margin of safety.

Operation at power levels based on the uncertainties in the calculation of CTP for the stated LEFM system conditions does not involve a significant reduction in a margin of safety. Calculation of the uncertainties associated with the measurement of core thermal power for these plant conditions as well as existing plant instrumentation and procedures ensure that the licensed thermal power and the thermal power level at which the Emergency Core Cooling Systems have been analyzed in accordance with Appendix K to 10 CFR 50 will not be exceeded.

License Amendment Request Expanded Actions for LEFM Conditions Page 19 of 20 Docket Nos. 50-277 and 50-278 Evaluation of Proposed Changes Therefore, the proposed change does not involve a significant reduction in a margin of safety.

5.4 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 Commissions regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or the health and safety of the public.

Based on the above evaluation, EGC concludes that the proposed amendment presents no significant hazards consideration under the standards set forth in 10 CFR 50.92, paragraph (c), and accordingly, a finding of no significant hazards consideration is justified.

6.0 ENVIRONMENTAL CONSIDERATION

10 CFR 51.22, "Criterion for categorical exclusion; identification of licensing and regulatory actions eligible for categorical exclusions or otherwise not requiring environmental review," addresses requirements for submitting environmental assessments as part of licensing actions. 10 CFR 51.22, paragraph (c)(9) states that a categorical exclusion applies for Part 50 license amendments that meet the following criteria:

i.

No significant hazards consideration (as defined in 10 CFR 50.92(c));

ii.

No significant change in the types or significant increase in the amounts of any effluents that may be released offsite; and iii.

No significant increase in individual or cumulative occupational radiation exposure.

The proposed change does not involve a significant hazards consideration. No new accident scenarios, failure mechanisms, or limiting single failures are introduced as a result of the proposed change. Operation in accordance with the proposed license amendments will not involve a significant reduction in a margin of safety.

No significant changes in types or amounts of effluents released into the environment will occur as a result of the proposed change. The Pennsylvania Department of Environmental Protection (PDEP) National Pollutant Discharge Elimination System (NPDES) permit provides the effluent limitations and monitoring requirements for wastewater at the site.

There is no 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, paragraph (c)(9). Therefore, pursuant to 10 CFR 51.22, paragraph (b), no environmental impact statement or environmental assessment needs to be prepared in connection with the proposed amendment.

License Amendment Request Expanded Actions for LEFM Conditions Page 20 of 20 Docket Nos. 50-277 and 50-278 Evaluation of Proposed Changes

7.0 REFERENCES

1. Exelon letter to NRC, Request for License Amendment Regarding Measurement Uncertainty Recapture Power Uprate, dated February 17, 2017 (ADAMS Accession No. ML17048A444)

2. NRC letter to Exelon, Peach Bottom Atomic Power Station, Units and 3 - Issuance of License Amendment Re: Measurement Uncertainty Recapture Power Uprate dated November 15, 2017 (ML17286A013)

3. Letter from NRC to John L. Skolds, Peach Bottom Atomic Power Station, Units 2 And 3

- Issuance of Amendment Re: 1.62% Increase In Licensed Power Level (TAC Nos.

MB5192 and MB5193), dated November 22, 2002

4. NRC letter to Exelon, Peach Bottom Atomic Power Station, Units and 3 - Issuance of License Amendment Re: Extended Power Uprate, (TAC Nos. ME9631 and ME9632),

dated August 14, 2014 (Accession No. ML14133A046)

5. Caldon (now Cameron) Topical Report ER-157P-A, Supplement to Caldon Topical Report ER-80P: Basis for Power Uprates with an LEFM TM or an LEFM CheckPlus TM System, Rev. 8, dated May 2008

6. Caldon (now Cameron) Topical Report ER-80P, Improving Thermal Power Accuracy and Plant Safety While Increasing Operating Power Level Using the LEFM + System, Rev 0 dated March 1997

7. NRC letter to Florida Power and Light Company, Turkey Point Units 3 and 4 - Issuance of Amendments Regarding Extended Power Uprate, dated June 15, 2012 (ML11293A365)

8. NRC letter to Florida Power and Light Company, St. Lucie Plant, Unit 1 - Issuance of Amendments Regarding Extended Power Uprate, dated July 9, 2012 (ML12191A220)

9. NRC letter to Florida Power and Light Company, St. Lucie Plant, Unit 2 - Issuance of Amendments Regarding Extended Power Uprate, dated September 24, 2012 (ML12235A463)

10. ASME PTC 19.1-1998, Test Uncertainty, Instruments and Apparatus, American Society of Mechanical Engineers, 1998

11. ANSI/ASME PTC-6 Report 1985, Guidance for the Evaluation of Measurement Uncertainty in Performance Tests of Steam Turbines

12. Exelon letter to NRC, Request for License Amendment Regarding Measurement Uncertainty Recapture Power Uprate - Supplement 1 - Request for Non-Proprietary Version of Cameron Corporation Proprietary Documents, dated March 20, 2017 (ADAMS Accession No. ML17080A067)

ATTACHMENT 2 License Amendment Request Peach Bottom Atomic Power Station, Units 2 and 3 Docket Nos. 50-277 and 50-278 License Amendment Request - Expanded Actions for LEFM Conditions Markup of Proposed Technical Requirements Manual and Bases Pages (For Information Only)

Unit 2 3.20-1 3.20-2 3.20-3 3.20-4 B 3.20-1 B 3.20-2 B 3.20-3 Unit 3 3.20-1 3.20-2 3.20-3 3.20-4 B 3.20-1 B 3.20-2 B 3.20-3

Leading Edge Flow Meter (LEFM) System 3.20 PBAPS UNIT 2 3.20-1 Revision 4a 3.20 LEADING EDGE FLOW METER (LEFM) SYSTEM TRMS 3.20 Three Leading Edge Flow Meters (LEFM) shall be NORMAL and providing flow input to Core Thermal Power calculation.

APPLICABILITY:

MODE 1 with THERMAL POWER > 3951 MWt COMPENSATORY MEASURES

NOTE ----------------------------------------------------------

See Bases for Definitions of a Flow Meter in NORMAL, MAINTENANCE and FAIL status.

Separate Condition entry is allowed for each Flow Meter.

CONDITION REQUIRED COMPENSATORY MEASURE COMPLETION TIME A.

One or more Flow Meters in MAINTENANCE A.1 Replace flow input to the Core Thermal Power calculation from the affected Flow Meter with input from the associated calibrated feedwater flow nozzle.

AND A.2 Restore affected Flow Meter to NORMAL and ensure it is providing flow input to the Core Thermal Power calculation.

2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months 72 hours

Leading Edge Flow Meter (LEFM) System 3.20 PBAPS UNIT 2 3.20-2 Revision 4a B.

Required Compensatory Measure and associated Completion Time of Condition A not met.

B.1.1 Reduce MAPL to less than or equal to value listed in Table 3.20-1.

AND B.1.2 Ensure flow input to the Core Thermal Power calculation is from the affected Flow Meter in MAINTENANCE.

OR B.2 Reduce MAPL to less than or equal to 3951 MWt Immediately Immediately Immediately C.

One Flow Meter in FAIL or not providing flow input to the Core Thermal Power calculation.

C.1 Replace flow input to the Core Thermal Power calculation from affected Flow Meter with input from the associated calibrated feedwater flow nozzle.

AND C.2 Restore affected Flow Meter to NORMAL and ensure it is providing flow input to the Core Thermal Power calculation.

2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months 72 hours

Leading Edge Flow Meter (LEFM) System 3.20 PBAPS UNIT 2 3.20-3 Revision 4a D.

Required Compensatory Measure and associated Completion Time of Condition C not met.

D.1.1 Reduce MAPL to less than or equal to 3982 MWt.

AND D.1.2 Ensure flow input to the Core Thermal Power calculation is from the associated feedwater flow nozzle.

OR D.2 Reduce MAPL to less than or equal to 3951 MWt Immediately Immediately Immediately E.

Two or more Flow Meters in FAIL or not providing flow input to the Core Thermal Power calculation.

E.1 Replace flow input to the Core Thermal Power calculation from affected Flow Meters with input from the associated calibrated feedwater flow nozzles.

AND E.2 Restore affected Flow Meters to NORMAL and ensure they are providing flow input to the Core Thermal Power calculation.

2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months 72 hours

Leading Edge Flow Meter (LEFM) System 3.20 PBAPS UNIT 2 3.20-4 Revision 4a F.

Required Compensatory Measure and associated Completion Time of Condition E not met.

F.1 Reduce MAPL to less than or equal to 3951 MWt.

Immediately LEFM TEST REQUIREMENTS TEST FREQUENCY TR 3.20.1 Perform CHANNEL CALIBRATION 24 months Table 3.20-1 Allowable MAPL for LEFM System Status LEFM System Status MAPL (MWt) 1 Flow Meter in MAINTENANCE, 2 in NORMAL 4015 2 Flow Meters in MAINTENANCE, 1 in NORMAL 4012 3 Flow Meters in MAINTENANCE, 0 in NORMAL 4009

PBAPS UNIT 2 B 3.20-1 Revision 4a Leading Edge Flow Meter (LEFM) System B 3.20 B 3.20 LEADING EDGE FLOW METER (LEFM) SYSTEM BASES This TRMS is provided to ensure that Core Thermal Power (CTP) is maintained at a level consistent with the feedwater flow measurement uncertainty. The three LEFM System Flow Meters shall be NORMAL and providing flow input to the CTP calculation for power operations above 3951 MWt or CTP must be limited in accordance with this TRMS. This TRMS allows Separate Condition Entry for each LEFM System Flow Meter.

The LEFM System consists of three Flow Meters, one in each of the three feedwater lines. Each Flow Meter contains flow transducers arranged in two planes. Plane 1 consists of flow transducer paths 1 through 4 and Plane 2 consists of flow transducer paths 5 through 8. The flow data from a Flow Meter with a single functioning plane has greater associated measurement uncertainty than that from a Flow Meter with both planes functioning, but less associated measurement uncertainty than that from a feedwater flow nozzle (Venturi), except within the first 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months following Venturi calibration. It has been demonstrated that Venturi-supplied flow data exhibits an insignificant deviation during this period following calibration by a Flow Meter with both planes functioning (see Reference 3). For this reason, following the loss of an LEFM plane, swapping flow input to the associated calibrated Venturi is preferable for the first 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months , and CTP is not required to be lowered during this time interval.

The LEFM System computer converts the Flow Meter data into feedwater flow and temperature signals for that loop, and provides a self-check via Plant Monitoring System computer alarms. There are three possible statuses for a Flow Meter:

NORMAL, MAINTENANCE, and FAIL.

A Flow Meter status is considered NORMAL IF:

The LEFM System Computer indicates that Flow Meter status (mode) to be Normal (also known as CheckPlus Mode).

A Flow Meter status is considered MAINTENANCE IF:

The LEFM System Computer indicates that Flow Meter status (mode) to be Maintenance (also known as Check Mode).

A Flow Meter status is considered FAIL IF:

The LEFM System Computer indicates that Flow Meter status (mode) to be Fail.

PBAPS UNIT 2 B 3.20-2 Revision 4a Leading Edge Flow Meter (LEFM) System B 3.20 The Flow Meter status is determined and reported by the LEFM System computer based upon the number of functional planes in the Flow Meter and upon its data quality. For additional background information on the criteria used by the LEFM System computer to determine the status of an individual Flow Meter, see References 1 and 2.

When this TRMS is applicable (greater than 3951 MWt) and except as explicitly directed otherwise in the TRM, the feedwater flow input to the Core Thermal Power calculation from a Flow Meter that is not NORMAL is to be replaced with that from the associated calibrated feedwater flow nozzle (Venturi). A feedwater flow nozzle is calibrated when a correction factor based on the LEFM/Venturi ratio is applied to the feedwater flow nozzle measurement in accordance with station operating procedures.

This will ensure accuracy of the Core Thermal Power calculation while relying on the feedwater flow nozzle input to the Core Thermal Power calculation. See Reference 3.

The feedwater flow signal from a Flow Meter in FAIL status is to remain replaced by its corresponding feedwater flow nozzle as long as the Flow Meter remains in FAIL. In the case of a single Flow Meter in FAIL, Compensatory Measure D.1.1 allows for operation at an intermediate power level of 3982 MWt beyond 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months , since long-term feedwater flow nozzle instrument drift has been accounted for in the uncertainty analysis (Reference 4). Compensatory Measure D.1.2 does not require the flow nozzle to be calibrated by its associated LEFM since the additional uncertainty is encompassed by the lower intermediate power level.

The remaining two Flow Meters must remain in either NORMAL or MAINTENANCE status. If a second LEFM enters FAIL mode, Condition E applies and the completion time clocks for Compensatory Measures E.1 and E.2 immediately start.

The feedwater flowrate signal from a Flow Meter in MAINTENANCE status is to provide input to the Core Thermal Power calculation when operating at an intermediate power level specified in Table 3.20-1. These intermediate power levels are predicated upon all three feedwater flow inputs being provided by Flow Meters that are all in either NORMAL or MAINTENANCE status.

If all three Flow Meters are restored to the NORMAL status after entry into Required Compensatory Measure B.1, then all three Flow Meters must provide feedwater flow input to the Core Thermal Power calculation prior to raising power greater than the value specified in Table 3.20-1.

If the status of a Flow Meter changes to a status other than NORMAL after a TRM Condition has been entered for that Flow Meter (i.e., status from MAINTENANCE to FAIL or FAIL to MAINTENANCE), then the Completion Time(s) for the new Required Compensatory Measure(s) of the applicable TRM Condition(s) must be completed based upon a start time corresponding to initial entry into the TRM for the specific Flow Meter. The accuracy of the calibrated feedwater flow nozzle (Venturi) can only be credited for 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months based on the insignificant instrument drift, see Reference 3. If

PBAPS UNIT 2 B 3.20-3 Revision 4a Leading Edge Flow Meter (LEFM) System B 3.20 the Flow Meter cannot be restored to NORMAL in the 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months Completion Time, then CTP must be lowered as directed by the appropriate Required Compensatory Measure based on Flow Meter status at the time.

The analysis supporting the allowable power levels provided in the TRM is contained in References 1 and 2.

The LEFM System and feedwater flow nozzle transmitter calibration are checked at regularly scheduled intervals. The frequency has been selected based on the reliability of the system. Additionally, parameters which input into the Core Thermal Power calculation are routinely validated to be within established bands.

CTP restrictions imposed by this TRM are controlled via plant procedures by changing the Maximum Allowable Power Level (MAPL). Changing the MAPL setting within the Plant Monitoring System computer ensures operation is within allowable limits.

REFERENCES:

1. Calculation PM-1201, Uncertainty Analysis for Thermal Power Determination at PB2 Using the LEFM CheckPlus System, VNDR DWG NUMBER ER464

2. Calculation PM-1202, Uncertainty Analysis for Thermal Power Determination at PB3 Using the LEFM CheckPlus System, VNDR DWG NUMBER ER463

3. Technical Evaluation 624827, LEFM SYSTEM POST-MUR LAR TECHNICAL EVALUATION

4. Calculation PM-1209, Peach Bottom Feedwater Flow Uncertainty in the Plant Computer as Measured by the Flow Nozzles Without Calibration by the LEFM

Leading Edge Flow Meter (LEFM) System 3.20 PBAPS UNIT 3 3.20-1 Revision 3a 3.20 LEADING EDGE FLOW METER (LEFM) SYSTEM TRMS 3.20 Three Leading Edge Flow Meters (LEFM) shall be NORMAL and providing flow input to Core Thermal Power calculation.

APPLICABILITY:

MODE 1 with THERMAL POWER > 3951 MWt COMPENSATORY MEASURES

NOTE ----------------------------------------------------------

See Bases for Definitions of a Flow Meter in NORMAL, MAINTENANCE and FAIL status.

Separate Condition entry is allowed for each Flow Meter.

CONDITION REQUIRED COMPENSATORY MEASURE COMPLETION TIME A.

One or more Flow Meters in MAINTENANCE A.1 Replace flow input to the Core Thermal Power calculation from the affected Flow Meter with input from the associated calibrated feedwater flow nozzle.

AND A.2 Restore affected Flow Meter to NORMAL and ensure it is providing flow input to the Core Thermal Power calculation.

2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months 72 hours

Leading Edge Flow Meter (LEFM) System 3.20 PBAPS UNIT 3 3.20-2 Revision 3a B.