ML121220204

Issuance of Amendment Reactivity Anomalies Surveillance

ML121220204
Person / Time
Site:	Peach Bottom
Issue date:	05/25/2012
From:	Richard Ennis Plant Licensing Branch 1
To:	Pacilio M Exelon Nuclear
Ennis R, NRR/DORL, 415-1420
References
TAC ME6356, TAC ME6357
Download: ML121220204 (20)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 May 25,2012 Mr. Michael J. Pacilio President and Chief Nuclear Officer Exelon Nuclear 4300 Winfield Road Warrenville, IL 60555

SUBJECT:

PEACH BOTTOM ATOMIC POWER STATION, UNITS 2 AND 3 -ISSUANCE OF AMENDIVIENTS RE: REACTIVITY ANOMALIES SURVEILLANCE (TAC NOS. ME6356 AND ME6357)

Dear Mr. Pacilio:

The Commission has issued the enclosed Amendments Nos. 284 and 287 to Renewed Facility Operating License Nos. DPR-44 and DPR-56 for Peach Bottom Atomic Power Station, Units 2 and 3. These amendments consist of changes to the Technical Specifications (TSs) and Facility Operating Licenses in response to your application dated June 2, 2011, as supplemented by letter dated November 10, 2011.

The amendments modify TS 3.1.2, "Reactivity Anomalies," to change the method used to perform the reactivity anomaly surveillance. Specifically, the amendments allow performance of the surveillance based on the difference between the monitored (i.e., actual) core reactivity and the predicted core reactivity. The surveillance was previously performed based on the difference between the monitored control rod density and the predicted control rod density.

A copy of the safety evaluation is also enclosed. Notice of Issuance will be included in the Commission's Biweekly Federal Register Notice.

Sincerely, Richard B. Ennis, Senior Project Manager Plant Licensing Branch 1-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-277 and 50-278

Enclosures:

1. Amendment No. 284 to Renewed DPR-44

2. Amendment No. 287 to Renewed DPR-56

3. Safety Evaluation cc w/encls: Distribution via Listserv

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 EXELON GENERATION COMPANY, LLC PSEG NUCLEAR LLC DOCKET NO. 50-277 PEACH BOTTOM ATOMIC POWER STATION, UNIT 2 AMENDMENT TO RENEWED FACILITY OPERATING LICENSE Amendment No. 284 Renewed License No. DPR-44

1. The Nuclear Regulatory Commission (the Commission) has found that:

A. The application for amendment by Exelon Generation Company, LLC (Exelon Generation Company), and PSEG Nuclear LLC (the licensees), dated June 2, 2011, as supplemented by letter dated November 10, 2011, complies with the standards and requirements of the Atomic Energy Act of 1954, as amended (the Act), and the Commission's rules and regulations set forth in 10 CFR Chapter I; B. The facility will operate in conformity with the application, the provisions of the Act, and the rules and regulations of the Commission; C. There is reasonable assurance (i) that the activities authorized by this amendment can be conducted without endangering the health and safety of the public, and (ii) that such activities will be conducted in compliance with the Commission's regulations; D. The issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public; and E. The issuance of this amendment is in accordance with 10 CFR Part 51 of the Commission's regulations and all applicable requirements have been satisfied.

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2. Accordingly, the license is amended by changes to the Technical Specifications as indicated in the attachment to this license amendment, and paragraph 2.C(2) of Renewed Facility Operating License No. DPR-44 is hereby amended to read as follows:

(2) Technical Specifications The Technical Specifications contained in Appendices A and B, as revised through Amendment No. 284, are hereby incorporated in the renewed license.

Exelon Generation Company shall operate the facility in accordance with the Technical Specifications.

3. This license amendment is effective as of its date of issuance and shall be implemented within 60 days.

FOR THE NUCLEAR REGULATORY COMMISSION Y-"y\ V'-'--...w-_ _ _-

Meena K. Khanna, Chief Plant Licensing Branch 1-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation

Attachment:

Changes to the Technical Specifications and Facility Operating License Date of Issuance: May 25, 2012

ATTACHMENT TO LICENSE AMENDMENT NO. 284 RENEWED FACILITY OPERATING LICENSE NO. DPR-44 DOCKET NO. 50-277 Replace the following page of the Renewed Facility Operating License with the attached revised page. The revised page is identified by amendment number and contains marginal lines indicating the areas of change.

Remove Insert Page 3 Page 3 Replace the following pages of the Appendix A Technical Specifications with the attached revised pages. The revised pages are identified by amendment number and contain marginal lines indicating the areas of change.

Remove Insert 3.1-5 3.1-5 3.1-6 3.1-6

(5) Exelon Generation Company, pursuant to the Act and 10 CFR Parts 30 and 70, to possess, but not to separate, such byproduct and special nuclear material as may be produced by operation of the facility, and such Class B and Class C low-level radioactive waste as may be produced by the operation of Limerick Generating Station, Units 1 and 2.

C. This renewed license shall be deemed to contain and is subject to the conditions specified in the following Commission regulations in 10 CFR Chapter I: Part 20, Section 30.34 of Part 30, Section 40.41 of Part 40, Section 50.54 of Part 50, and Section 70.32 of Part 70; all applicable provisions of the Act and the rules, regulations, and orders of the Commission now or hereafter in effect; and is subject to the additional conditions specified below:

(1) Maximum Power Level Exelon Generation Company is authorized to operate the Peach Bottom Atomic Power Station, Unit 2, at steady state reactor core power levels not in excess of 3514 megawatts thermal.

(2) Technical Specifications The Technical Specifications contained in Appendices A and B, as revised through Amendment No. 284, are hereby incorporated in the license. Exelon Generation Company shall operate the facility in accordance with the Technical Specifications.

(3) Physical Protection Exelon Generation Company shall fully implement and maintain in effect all provisions of the Commission-approved physical security, training and qualification, and safeguards contingency plans including amendments made pursuant to provisions of the Miscellaneous Amendments and Search Requirements revisions to 10 CFR 73.55 (51 FR 27817 and 27822), and the authority of 10 CFR 50.90 and 10 CFR 50.54(p). The combined set of plans 1 , submitted by letter dated May 17, 2006, is entitled: "Peach Bottom Atomic Power Station Security Plan, Training and Qualification Plan, Safeguards Contingency Plan, and Independent Spent Fuel Storage Installation Security Program, Revision 3." The set contains Safeguards Information protected under 10 CFR 73.21.

Exelon Generation Company shall fully implement and maintain in effect all provisions of the Commission-approved cyber security plan (CSP),

including changes made pursuant to the authority of 10 CFR 50.90 and 10 CFR 50.54(p). The Exelon Generation Company CSP was approved by License Amendment No. 283.

(4) Fire Protection The Exelon Generation Company shall implement and maintain in effect all provisions of the approved fire protection program as described in the Updated Final Safety Analysis Report for the facility, and as approved in the NRC Safety Evaluation Report (SER) dated May 23, 1979, and Supplements dated August 14, September 15, October 10 and November 24, 1980, and in the NRC SERs dated September 16, 1993, and August 24, 1994, subject to the following provision:

1 The Training and Qualification Plan and Safeguards Contingency Plan are Appendices to the Security Plan.

Renewed License No. DPR-44 Revised by letter dated October 28, 2004 Revised by letter dated May 29, 2007 Amendment No. 284 Page 3

Reactivity Anomalies 3.1.2 3.1 REACTIVITY CONTROL SYSTEMS 3.1.2 Reactivity Anomalies LCO 3.1.2 The reactivity difference between the monitored core kMf and the predi cted core keff sha 11 be wi thi n +/- 1% ak/k.

APPLICABILITY: MODES 1 and 2.

ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. Core reactivity A.1 Restore core 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> difference not within reactivity difference 1imit. to within limit.

B. Required Action and B.1 Be in MODE 3. 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> associated Completion Time not met.

PBAPS UNIT 2 3.1-5 Amendment No. 284

Reactivity Anomalies 3.1.2 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.1.2.1 Verify core reactivity difference between Once within the monitored core keff and the predicted 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> after core keff ; 5 within +/- U Ak/k. reaching equilibrium conditions following startup after fuel movement withi n the reactor pressure vessel or control rod replacement

.8RIl 1000 MWD/T thereafter during operations in MODE 1 PBAPS UN IT 2 3.1-6 Amendment No.284

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 EXELON GENERATION COMPANY, LLC PSEG NUCLEAR LLC DOCKET NO. 50-278 PEACH BOTTOM ATOMIC POWER STATION, UNIT 3 AMENDMENT TO RENEWED FACILITY OPERATING LICENSE Amendment No. 287 Renewed License No. DPR-56 1 The Nuclear Regulatory Commission (the Commission) has found that:

A. The application for amendment by Exelon Generation Company, LLC (Exelon Generation Company), and PSEG Nuclear LLC (the licensees), dated June 2, 2011, as supplemented by letter dated November 10, 2011, complies with the standards and requirements of the Atomic Energy Act of 1954, as amended (the Act), and the Commission's rules and regulations set forth in 10 CFR Chapter I; B. The facility will operate in conformity with the application, the provisions of the Act, and the rules and regulations of the Commission; C. There is reasonable assurance (i) that the activities authorized by this amendment can be conducted without endangering the health and safety of the public, and (ii) that such activities will be conducted in compliance with the Commission's regulations; D. The issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public; and E. The issuance of this amendment is in accordance with 10 CFR Part 51 of the Commission's regulations and all applicable requirements have been satisfied.

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2. Accordingly, the license is amended by changes to the Technical Specifications as indicated in the attachment to this license amendment, and paragraph 2.C(2) of Renewed Facility Operating License No. DPR-56 is hereby amended to read as follows:

(2) Technical Specifications The Technical Specifications contained in Appendices A and B, as revised through Amendment No. 287, are hereby incorporated in the renewed license.

Exelon Generation Company shall operate the facility in accordance with the Technical Specifications.

3. This license amendment is effective as of its date of issuance and shall be implemented within 60 days.

FOR THE NUCLEAR REGULATORY COMMISSION Meena K. Khanna, Chief Plant Licensing Branch 1-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation

Attachment:

Changes to the License and Technical Specifications Date of Issuance: May 25, 2012

ATTACHMENT TO LICENSE AMENDMENT NO. 287 RENEWED FACILITY OPERATING LICENSE NO. DPR-56 DOCKET NO. 50-278 Replace the following page of the Renewed Facility Operating License with the attached revised page. The revised page is identified by amendment number and contains marginal lines indicating the areas of change.

Remove Insert Page 3 Page 3 Replace the following pages of the Appendix A Technical Specifications with the attached revised pages. The revised pages are identified by amendment number and contain marginal lines indicating the areas of change.

Remove Insert 3.1-5 3.1-5 3.1-6 3.1-6

(S) Exelon Generation Company, pursuant to the Act and 10 CFR Parts 30 and 70, to possess, but not to separate, such byproduct and special nuclear material as may be produced by operation of the facility, and such Class B and Class C low-level radioactive waste as may be produced by the operation of Limerick Generating Station, Units 1 and 2.

C. This renewed license shall be deemed to contain and is subject to the conditions specified in the following Commission regulations in 10 CFR Chapter I: Part 20, Section 30.34 of Part 30, Section 40.41 of Part 40, Section SO.S4 of Part SO, and Section 70.32 of Part 70; all applicable provisions of the Act and the rules, regulations, and orders of the Commission now or hereafter in effect; and is subject to the additional conditions specified below:

(1) Maximum Power Level Exelon Generation Company is authorized to operate the Peach Bottom Atomic Power Station, Unit No.3, at steady state reactor core power levels not in excess of 3S14 megawatts thermal.

(2) Technical Specifications The Technical Specifications contained in Appendices A and B, as revised through Amendment No. 287, are hereby incorporated in the license. Exelon Generation Company shall operate the facility in accordance with the Technical Specifications. 1 (3) Physical Protection Exelon Generation Company shall fully implement and maintain in effect all provisions of the Commission-approved physical security, training and qualification, and safeguards contingency plans including amendments made pursuant to provisions of the Miscellaneous Amendments and Search Requirements revisions to 10 CFR 73.SS (S1 FR 27817 and 27822), and the authority of 10 CFR SO.90 and 10 CFR SO.S4(p). The combined set of plans 2, submitted by letter dated May 17, 2006, is entitled: "Peach Bottom Atomic Power Station Security Plan, Training and Qualification Plan, Safeguards Contingency Plan, and Independent Spent Fuel Storage Installation Security Program, Revision 3." The set contains Safeguards Information protected under 10 CFR 73.21.

Exelon Generation Company shall fully implement and maintain in effect all provisions of the Commission-approved cyber security plan (CSP),

including changes made pursuant to the authority of 10 CFR SO.90 and 10 CFR SO.S4(p). The Exelon Generation Company CSP was approved by License Amendment No. 286.

1Licensed power level was revised by Amendment No. 2S0, dated November 22, 2002, and will be implemented following the 14th refueling outage currently scheduled for Fall 2003.

2The training and Qualification Plan and Safeguards Contingency Plan and Appendices to the Security Plan.

Renewed License No. DPR-S6 Revised by letter dated October 28, 2004 Revised by letter dated November S, 2004 Revised by letter dated May 29,2007 Amendment No. 287 Page 3

Reactivity Anomalies 3.1. 2 3.1 REACTIVITY CONTROL SYSTEMS 3.1.2 Reactivity Anomalies LCO 3.1.2 The reactivity difference between the monitored core keff and the predicted core keff shall be within +/- 1% .1.k/k.

APPLICABILITY: MODES 1 and 2.

ACTIONS CONDIT ION REQUIRED ACTION CaMP LET ION TIME A. Core reactivity A.1 Restore core 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> difference not within reactivity difference limit. to withi n 1imit.

B. Required Action and B.1 Be in MODE 3. 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> associated Completion Time not met.

P8APS UN IT 3 3.1-5 Amendment No. 287

Reactivity Anomalies 3.1. 2 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.1.2.1 Verify core reactivity difference between Once within the monitored core keff and the predicted 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> after core keff is within +/- 1% ~k/k. reaching equilibrium conditions following startup after fuel movement within the reactor pressure vessel or control rod replacement 1000 MWD/T thereafter during operations in MODE 1 PBAPS UNIT 3 3.1-6 Amendment No. 287

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NOS. 284 AND 287 TO RENEWED FACILITY OPERATING LICENSE NOS. DPR-44 AND DPR-56 EXELON GENERATION COMPANY, LLC PSEG NUCLEAR LLC PEACH BOTTOM ATOMIC POWER STATION, UNITS 2 AND 3 DOCKET NOS. 50-277 AND 50-278

1.0 INTRODUCTION

By application dated June 2, 2011, as supplemented by letter dated November 10, 2011 (Agencywide Documents Access and Management System (ADAMS) Accession Nos.

ML111540122 and ML113180234, respectively), Exelon Generation Company, LLC (Exelon, the licensee), requested changes to the Technical Specifications (TSs) for Peach Bottom Atomic Power Station (PBAPS), Units 2 and 3. The proposed amendments would modify TS 3.1.2, "Reactivity Anomalies," to change the method used to perform the reactivity anomaly surveillance. Specifically, the amendments would allow performance of the surveillance based on the difference between the monitored (i.e., actual) core reactivity and the predicted core reactivity. The surveillance is currently performed based on the difference between the monitored control rod density and the predicted control rod density.

The supplement dated November 10, 2011, provided additional information that clarified the application, did not expand the scope of the application as originally noticed, and did not change the Nuclear Regulatory Commission (NRC or the Commission) staff's original proposed no significant hazards consideration determination as published in the Federal Register on September 6,2011 (76 FR 55129).

2.0 REGULATORY EVALUATION

The construction permit for PBAPS, Units 2 and 3, was issued by the Atomic Energy Commission (AEC) on January 31, 1968. As discussed in Appendix H to the PBAPS Updated Final Safety Analysis Report (UFSAR), during the construction/licensing process, both units were evaluated against the then-current AEC draft of the 27 General Design Criteria (GDC) issued in November 1965. On July 11, 1967, the AEC published for public comment, in the Federal Register (32 FR 10213), a revised and expanded set of 70 draft GDC (hereinafter referred to as the "draft GDC"). Appendix H of the PBAPS UFSAR contains an evaluation of the design basis of PBAPS, Units 2 and 3, against the draft GOC. The licensee concluded that PBAPS, Units 2 and 3, conforms to the intent of draft GDC.

Enclosure

- 2 On February 20, 1971, the AEC published in the Federal Register (36 FR 3255) a final rule that added Appendix A to Title 10 of the Code of Federal Regulations (10 CFR) Part 50, "General Design Criteria for Nuclear Power Plants" (hereinafter referred to as the "final GOC").

Differences between the draft GOC and final GOC included a consolidation from 70 to 64 criteria. As discussed in the NRC's Staff Requirements Memorandum for SECY-92-223, dated September 18, 1992 (ADAMS Accession No. IVlL003763736), the Commission decided not to apply the final GOC to plants with construction permits issued prior to May 21, 1971. At the time of promulgation of Appendix A to 10 CFR Part 50, the Commission stressed that the final GOC were not new requirements and were promulgated to more clearly articulate the licensing requirements and practice in effect at that time. Each plant licensed before the final GOC were formally adopted was evaluated on a plant-specific basis, determined to be safe, and licensed by the Commission.

The licensees for PBAPS, Units 2 and 3, have made changes to the facility over the life of the plant that may have invoked the final GOC. The extent to which the final GOC have been invoked can be found in specific sections of the UFSAR and in other plant-specific design and licensing basis documentation.

In Section 4.1 of Attachment 1 to the licensee's application dated June 2, 2011, the licensee cited the following final GOC as being applicable to the proposed amendment:

• GOC 26, "Reactivity control system redundancy and capability"

• GOC 28, "Reactivity limits"

• GOC 29, "Protection against anticipated operational occurrences" Consistent with the requirements in GOC 26, GOC, 28, and GOC 29: (1) reactivity shall be controllable such that subcriticality is achievable and maintainable under cold conditions (most reactive conditions); and (2) specified applicable fuel design limits must not be exceeded during normal operation and anticipated operational occurrences.

The NRC's regulatory requirements related to the content of the TSs are contained in 10 CFR 50.36, Technical specifications." Paragraph (c)(2)(i) of 10 CFR 50.36 states, in part, that limiting conditions for operation (LCOs) "are the lowest functional capability or performance levels of equipment required for safe operation of the facility." Paragraph (c)(3) of 10 CFR 50.36 states that surveillance requirements (SRs) are "requirements relating to test, calibration, or inspection to assure that the necessary quality of systems and components is maintained, that facility operation will be within safety limits, and that the limiting conditions for operation will be met."

As shown in Attachment 2 of the licensee's application dated June 2, 2011, the proposed amendment would revise PBAPS, Units 2 and 3, TS 3.1.2 to change LCO 3.1.2 and SR 3.1.2.1.

The specific changes are discussed below.

- 3 LCO 3.1.2 currently reads as follows:

The reactivity difference between the monitored rod density and the predicted rod density shall be within +/- 1% ~k/k.

The proposed amendment would revise LCO 3.1.2 to read as follows:

The reactivity difference between the monitored core keff and the predicted core keff shall be within +/- 1% ~k/k.

SR 3.1.2.1 currently reads as follows:

Verify core reactivity difference between the monitored rod density and the predicted rod density is within +/- 1% ~k/k.

The proposed amendment would revise SR 3.1.2.1 to read as follows:

Verify core reactivity difference between the monitored core keff and the predicted core keff is within +/- 1% ~k/k.

The reactivity anomaly check required by PBAPS TS 3.1.2 serves, in part, to satisfy the above GOC by comparing the observed reactivity behavior of the core (at hot operating conditions) to the expected reactivity behavior that was calculated prior to the start of operation for a particular operating cycle. This ensures that certain assumptions in the design-basis accident and transient safety analyses remain valid. Any difference between these two observations is compared to the TS 3.1.2 acceptance criterion of +/- 1% ~k/k and if the criterion is not met, the action required by the TS is then taken.

3.0 TECHNICAL EVALUATION

3.1 Current Method for Reactivity Anomaly Check The measure of criticality is the effective neutron multiplication factor, k-effective, or keff. The multiplication factor is the ratio of the rate of neutron production to neutron loss (e.g., due to absorption or leakage). Criticality is achieved when keff is equal to 1.0 (Le., neutron population is constant). When keff is less than 1.0, the reactor is subcritical. When keff is greater than 1.0, the reactor is supercritical. Reactivity is the measure of the fractional change in neutron population and is defined as (keff - 1)/keff . Therefore, in a critical reactor, reactivity is equal to zero. Although reactivity is unitless, it is assigned the units of ~k1k for convenience.

The PBAPS TSs currently require that the reactivity anomaly check be done by comparing a predicted control rod density (calculated prior to the start of operation for a particular cycle) to an actual control rod density. The comparison is done at the frequencies specified by SR 3.1.2.1.

As discussed in Exelon's application dated June 2, 2011:

The current method of performing the reactivity anomaly surveillance uses rod density for the comparison primarily because early core monitoring systems did

- 4 not calculate core critical keff values for comparison to design values. Instead, rod density was used as a convenient representation of core reactivity.

Allowing the use of a direct comparison of keff' as opposed to rod density, provides for a more direct measurement of core reactivity conditions and eliminates the limitations that exist for performing the core reac~ivity comparisons with rod density.

Comparison of predicted control rod density to actual control rod density is done via a set of reactivity anomaly curves. Development of the curves begins with predicted critical core keff values, which have been calculated for projected operating states and conditions throughout the life of the cycle, and their associated derived control rod patterns. A calculation is made of the number of notches inserted in these rod patterns and also the number of average notches required to make a change of +/- 1% fl.k/k around the predicted critical core keff values. The notches are converted to control rod density and plotted as a function of cycle exposure to produce a predicted control rod density curve with upper and lower bounds that represent the

+/- 1% fl.k/k TS acceptance criterion. As a result, the comparison is still based on critical keff' but with a "translation" of acceptance criteria to control rod density.

Under the current method, an anomaly would be the difference between the predicted and measured control rod density in the reactor under the existing conditions (e.g., time in cycle, power level and control rod pattern). The observed anomaly is then translated into a reactivity difference between the two values (the measured versus the predicted control rod density) for comparison to the TS limit of +/- 1% fl.k/k. If the limit is exceeded, the licensee has 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to restore the reactivity difference to within the limit or else be in hot shutdown in the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.

The licensee stated that, while being a convenient measurement of core reactivity, the control rod density method has limitations, such as differing impacts on reactivity from deeply inserted central control rods versus control rods on the outer edge of the core, or shallowly inserted rods.

The licensee indicated that it is not uncommon for reactivity anomaly concerns to arise during operation simply because of greater use of near-edge or shallow inserted control rods than anticipated, when in fact no true anomaly exists.

3.2 Proposed Method for Reactivity Anomaly Check The proposed change to the TSs would eliminate the translation of core keff into control rod density. Instead, the revised method for evaluating a potential reactivity anomaly would compare the measured core keff and the predicted core keff directly. The proposed TS change will not change the frequency of surveillance or any condition within the SR.

Advances in computational methods and computer technology support the proposed PBAPS TS amendment. PBAPS utilizes the Global Nuclear Fuels (GNF) core monitoring system, 3D MONICORE, which incorporates the three-dimensional (3D) core simulator code, PANACEA Version 11. The system allows for a direct comparison of predicted core keff to monitored core keff . Measured core keff is calculated by PANAC11 using measured plant operating data provided by 3D MONICORE. The predicted core keff' as a function of cycle exposure, is developed using PANAC 11 prior to the start of each operating cycle. The PANAC 11-computed

- 5 measured core keff behavior from the previous cycle is used as the starting point for the calculation. Any fuel vendor recommended adjustments due to planned changes in fuel design, core design, or operating strategy for the upcoming cycle are also incorporated into the development of the predicted core keff .

By letter dated March 11, 1999 (ADAMS Accession No. ML993140059), the NRC approved the power distribution uncertainty for the 3D MONICORE system by accepting licensing topical report NEDC-32694P, "Power Distribution Uncertainties for Safety Limit MCPR [minimum critical power ratio] Evaluation," with limitations, for referencing in license applications. Further, by letter dated November 10,1999 (ADAMS Accession No. ML993230184), the NRC staff documented an evaluation of a version of the PANACEA core simulator code, referred to as PANAC11. In that evaluation, the NRC staff concluded that a proposed improvement in General Electric (GE) steady-state methods (reflected in PANAC11) was acceptable and appropriate for inclusion into the GE licensing topical report for core design, NEDE-24011-P-A.

The NRC staff has reviewed the information provided by the licensee and concludes that the use of monitored (i.e., actual) to predicted core keff' instead of rod density: (1) eliminates the limitations described in Section 3.1 of this safety evaluation (SE); (2) provides for a technically superior comparison; and (3) is a simple and straightforward approach utilizing appropriate computer codes and methods.

The licensee also assessed the impact of this request on the PBAPS transient and accident analyses, and determined that the proposed changes will not affect any of the transient and accident analyses. This is because only the method of performing the reactivity anomaly surveillance is changing, and the proposed method will provide an adequate acceptable comparison as discussed above. Furthermore, the anomaly check will continue to be performed at the current required frequency. The NRC staff agrees with this assessment and therefore concludes that the proposed surveillance will continue to ensure that the assumptions in the transient and accident analysis regarding core reactivity remain valid with this change.

3.3 Technical Evaluation Conclusion The NRC staff has reviewed the licensee's request to revise TS 3.1.2 and, based on the discussion above in SE Sections 3.1 and 3.2, concludes that the proposed TS revisions are acceptable and will provide an improved approach for the determination of reactivity anomalies.

Therefore, the NRC staff concludes that the proposed amendment is acceptable.

Exelon's application dated June 2, 2011, also provided proposed changes to the TS Bases to be implemented with the associated TS changes discussed above. The TS Bases pages were provided for information only and will be revised in accordance with the TS Bases Control Program.

4.0 STATE CONSULTATION

In accordance with the Commission's regulations, the Pennsylvania State official was notified of the proposed issuance of the amendments. The State official had no comments.

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5.0 ENVIRONMENTAL CONSIDERATION

The amendments change a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and changes SRs.

The NRC staff has determined that the amendments involve no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that the amendments involve no significant hazards consideration, and there has been no public comment on such finding (76 FR 55129). Accordingly, the amendments meet the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9). Pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendments.

6.0 CONCLUSION

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

Principal Contributors: A. K. Heller A. Attard R. Ennis Date: May 25, 2012

May 25,2012 Mr. Michael J. Pacilio President and Chief Nuclear Officer Exelon Nuclear 4300 Winfield Road Warrenville, IL 60555

SUBJECT:

PEACH BOTTOM ATOMIC POWER STATION, UNITS 2 AND 3 -ISSUANCE OF AMENDMENTS RE: REACTIVITY ANOMALIES SURVEILLANCE (TAC NOS. ME6356 AND ME6357)

Dear Mr. Pacilio:

The Commission has issued the enclosed Amendments Nos. 284 and 287 to Renewed Facility Operating License Nos. DPR-44 and DPR-56 for Peach Bottom Atomic Power Station, Units 2 and 3. These amendments consist of changes to the Technical Specifications (TSs) and Facility Operating Licenses in response to your application dated June 2, 2011, as supplemented by letter dated November 10, 2011.

The amendments modify TS 3.1.2, "Reactivity Anomalies," to change the method used to perform the reactivity anomaly surveillance. Specifically, the amendments allow performance of the surveillance based on the difference between the monitored (i.e., actual) core reactivity and the predicted core reactivity. The surveillance was previously performed based on the difference between the monitored control rod density and the predicted control rod density.

A copy of the safety evaluation is also enclosed. Notice of Issuance will be included in the Commission's Biweekly Federal Register Notice.

Sincerely, lraJ Richard B. Ennis, Senior Project Manager Plant Licensing Branch 1-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-277 and 50-278

Enclosures:

1. Amendment No. 284 to Renewed DPR-44

2. Amendment 1\10. 287 to Renewed DPR-56

3. Safety Evaluation cc w/encls: Distribution via Listserv DISTRIBUTION:

PUBLIC RidsAcrsAcnw_MailCTR Resource RidsNrrDssSnpb Resource LPL 1-2 R/F RidsOgcRp Resource RidsNrrDorlDpr Resource RidsRgn1 MailCenter Resource Ridsl'JrrDorILpI1-2 Resource RidsNrrDssStsbResource RidsNrrPMPeachBottom Resource GHill,OIS RidsNrrLAABaxter Resource KHelier, NRR/DSS/SNPB ADAMS Accession No* ML121220204 *concurred via email OFFICE LPL 1-2/PM LPL 1-2/LA

• SNPB/BC STSB/BC OGC LPL 1-2/BC NAME REnnis ABaxter AMendiola RElliott JLindel1 MKhanna DATE 5/22 05/02/12 514/12 5/9/12 5/21112 5/25/12 OFFICIAL RECORD COpy