ML16344A126

Issuance of Amendment Regarding Minimum Critical Power Ratio

ML16344A126
Person / Time
Site:	Hatch
Issue date:	01/06/2017
From:	Michael Orenak Plant Licensing Branch II
To:	Pierce C Southern Nuclear Operating Co
Orenak M, DORL/LPLII-1, 415-3229
References
CAC MF8309
Download: ML16344A126 (13)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 January 6, 2017 Mr. C. R. Pierce Regulatory Affairs Director Southern Nuclear Operating Company, Inc.

Post Office Box 1295, Bin - 038 Birmingham, AL 35201-1295

SUBJECT:

EDWIN I. HATCH NUCLEAR PLANT, UNIT NO. 2, ISSUANCE OF AMENDMENT REGARDING MINIMUM CRITICAL POWER RATIO (CAC NO. MF8309)

Dear Mr. Pierce:

The U.S. Nuclear Regulatory Commission has issued the enclosed Amendment No. 226 to Renewed Facility Operating License NPF-5 for the Edwin I. Hatch Nuclear Plant, Unit No. 2, in response to the license amendment application dated August 29, 2016, as supplemented by letter dated November 18, 2016. The amendment revises the Technical Specification value of the Safety Limit Minimum Critical Power Ratio to support operation in the next fuel cycle.

A copy of the related Safety Evaluation is also enclosed. A Notice of Issuance will be included in the Commission's biweekly Federal Register notice.

Sincerely,

~~

Michael Orenak, Project Manager Plant Licensing Branch 11-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-366

Enclosures:

1. Amendment No. 226 to NPF-5

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

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 SOUTHERN NUCLEAR OPERATING COMPANY, INC.

GEORGIA POWER COMPANY OGLETHORPE POWER CORPORATION MUNICIPAL ELECTRIC AUTHORITY OF GEORGIA CITY OF DALTON, GEORGIA DOCKET NO. 50-366 EDWIN I. HATCH NUCLEAR PLANT, UNIT NO. 2 AMENDMENT TO RENEWED FACILITY OPERATING LICENSE Amendment No. 226 Renewed License No. NPF-5

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

A. The application for amendment to the Edwin I. Hatch Nuclear Plant, Unit No. 2 (the facility) Renewed Facility Operating License No. NPF-5 filed by Southern Nuclear Operating Company, Inc. (the licensee), acting for itself, Georgia Power Company, Oglethorpe Power Corporation, Municipal Electric Authority of Georgia, and City of Dalton, Georgia (the owners), dated August 29, 2016, as supplemented by letter dated November 18, 2016, complies with the standards and requirements of the Atomic Energy Act of 1954, as amended (the Act), and the Commission's rules and regulations as 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 set forth in 10 CFR Chapter I; 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.

Enclosure 1

2. Accordingly, the license is hereby amended by page 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. NPF-5 is hereby amended to read as follows:

(2) Technical Specifications The Technical Specifications contained in Appendix A and the Environmental Protection Plan contained in Appendix B, as revised through Amendment No. 226 are hereby incorporated in the license. Southern Nuclear shall operate the facility in accordance with the Technical Specifications and the Environmental Protection Plan.

3. This license amendment is effective as of its date of issuance and shall be implemented prior to reactor startup following the Unit 2 spring 2017 refueling outage.

FOR THE NUCLEAR REGULATORY COMMISSION

~~~

Michael T. Markley, Chief Plant Licensing Branch 11-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation

Attachment:

Changes to Renewed Facility Operating License No. NPF-5 and the Technical Specifications Date of Issuance: January 6, 2017

ATTACHMENT TO LICENSE AMENDMENT NO. 226 EDWIN I. HATCH NUCLEAR PLANT. UNIT NO. 2 RENEWED FACILITY OPERATING LICENSE NO. NPF-5 DOCKET NO. 50-366 Replace the following pages of the License and the Appendix A Technical Specifications (TSs) with the attached revised pages. The revised pages are identified by amendment number and contain marginal lines indicating the areas of change.

Remove Pages Insert Pages License License Page 4 Page4 TSs TSs 2.0-1 2.0-1

(6) Southern Nuclear, pursuant to the Act and 10 CFR Parts 30 and 70, to possess, but not separate, such byproduct and special nuclear materials as may be produced by the operation of the facility.

(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 the additional conditions 2 specified or incorporated below:

(1) Maximum Power Level Southern Nuclear is authorized to operate the facility at steady sate reactor core power levels not in excess of 2,804 megawatts thermal, in accordance with the conditions specified herein.

(2) Technical Specifications The Technical Specifications (Appendix A) and the Environmental Protection Plan (Appendix 8); as revised through Amendment No. 226 are hereby incorporated in the renewed license. Southern Nuclear shall operate the facility in accordance with the Technical Specifications and the Environmental Protection Plan.

(3) Additional Conditions The matters specified in the following conditions shall be completed to the satisfaction of the Commission within the stated time periods following the issuance of the renewed license or within the operational restrictions indicated. The removal of these conditions shall be made by an amendment to the license supported by a favorable evaluation by the Commission.

(a) Fire Protection Southern Nuclear shall implement and maintain in effect all provisions of the fire protection program, which is referenced in the Updated Final Safety Analysis Report for the facility, as contained 2 The original licensee authorized to possess, use, and operate the facility with Georgia Power Company (GPC). Consequently, certain historical references to GPC remain in certain license conditions.

Renewed License No. NPF-5 Amendment No. 226

SLs 2.0 2.0 SAFETY LIMITS (SLs) 2.1 SLs 2.1.1 Reactor Core SLs 2.1.1.1 With the reactor steam dome pressure < 685 psig or core flow

< 10% rated core flow:

THERMAL POWER shall bes 24% RTP.

2.1.1.2 With the reactor steam dome pressure ~ 685 psig and core flow

~ 10% rated core flow:

MCPR shall be~ 1.1 Ofor two recirculation loop operation or~ 1.13 for single recirculation loop operation.

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

2.1.2 Reactor Coolant System (RCS) Pressure SL Reactor steam dome pressure shall bes 1325 psig.

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

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

HATCH UNIT2 2.0-1 Amendment No.2 2 6

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 226 TO RENEWED FACILITY OPERATING LICENSE NO. NPF-5 SOUTHERN NUCLEAR OPERATING COMPANY, INC.

EDWIN I. HATCH NUCLEAR PLANT, UNIT NO. 2 DOCKET NO. 50-366 1.0. INTRODUCTION By letter dated August 29, 2016 (Agencywide Documents Access and Management System (ADAMS), Accession No. ML16245A257), as supplemented by letter dated November 18, 2016 (ADAMS Accession No. ML16328A303), Southern Nuclear Operating Company, Inc. (SNC, the licensee), submitted a license amendment request (LAR) for the Edwin I. Hatch Nuclear Plant (HNP), Unit No. 2. The proposed amendment revises technical specification (TS) 2.0, "Safety Limits (SLs)," by changing the safety limit minimum critical power ratio (SLMCPR) for both single and dual recirculation loop operation. The supplement dated November 18, 2016, provided additional information that clarified the application, did not expand the scope of the application as originally noticed, and did not change the staff's original proposed no significant hazards consideration determination as published the Federal Register on October 11, 2016 (81 FR 70184).

The U.S. Nuclear Regulatory Commission (NRC, the Commission) staff's evaluation of the licensee's proposed changes is provided below.

2.0 REGULATORY EVALUATION

2.1 Background Fuel design limits can be exceeded if the fuel produces heat equal to or greater than critical power. In a boiling water reactor (BWR), heat produced by the fuel causes the water to partially vaporize in a stable process called nucleate boiling. As the amount of heat produced by the fuel increases, more of the water vaporizes and the vapor production changes the way the water boils. At a certain point, the efficiency of heat removal is impeded by vapor production and the temperature of the fuel cladding rises disproportionately to the heat generated. Critical power is a term used for the power at which the fuel departs from nucleate boiling and enters a transition to film boiling.

For BWRs, the critical power may be predicted using a correlation known as the GE (General Electric) critical quality boiling length correlation, or better known as the GEXL correlation. Due

to core wide and operational variations, the margin to boiling transition is most easily described in terms of a critical power ratio (CPR), which is defined as the rod critical power, as calculated by GEXL, divided by the actual rod power. The more a CPR value exceeds 1.0, the greater the margin to boiling transition is. The SLMCPR represents a conservative margin relative to the conditions required to maintain fuel cladding integrity and is calculated using a statistical process that takes into account operating parameters and uncertainties. The SLMCPR is verified on a cycle-specific basis because it is necessary to account for the core configuration-specific neutronic and thermal-hydraulic response.

2.2 Proposed Changes The current (i.e, Cycle 24) TS 2.0, "Safety Limits," Section 2.1.1.2 states:

With the reactor steam dome pressure 2: 685 psig and core flow 2: 10% rated core flow:

MCPR shall be 2: 1.09 for two recirculation loop operation or 2: 1.12 for single recirculation loop operation.

The revised TS 2.0, "Safety Limits," Section 2.1.1.2 states:

With the reactor steam dome pressure 2: 685 psig and core flow 2: 10% rated core flow:

MCPR shall be 2: 1.10 for two recirculation loop operation or 2: 1.13 for single recirculation loop operation.

2.3 Regulations and Guidance The regulation in Title 10 of the Code of Federal Regulations (10 CFR) 50.36(c)(1 )(i)(A) requires that safety limits be included in a plant-specific TS. Safety limits are limits upon important process variables that are found to be necessary to reasonably protect the integrity of certain physical barriers that guard against the uncontrolled release of radioactivity.

The regulation in 10 CFR Part 50, Appendix A, General Design Criterion (GDC) 10 states, in part, that the reactor core and associated coolant, control, and protection systems shall be designed to assure that specified acceptable fuel design limits are not exceeded during any condition of normal operation, including the effects of anticipated operational occurrences.

Additionally, NUREG-800, "Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants: LWR Edition," Standard Review Plan (SRP) Section 4.4, "Thermal and Hydraulic Design," (ADAMS Accession No. ML070550060) states that the Critical Power Ratio is to be established such that at least 99.9 percent of the fuel rods in the core would not be expected to experience departure from nucleate boiling or boiling transition during normal operation or anticipated operational occurrences. The guidance provided within the SRP forms the basis of the NRC staff's review and ensures that the criteria of GDC 1O are met.

Generic Letter 88-16, "Removal of Cycle-Specific Parameter Limits from Technical Specifications," (ADAMS Accession No. ML031130447) provides guidance on modifying cycle-specific parameter limits in the TS. For each fuel vendor licensee, NRC approves the licensing and analytical method and codes used to perform the safety analyses. For each

operating cycle, the licensee or the fuel vendor performs the cycle-specific safety analyses using the NRG-approved licensing methodology and the NRG-approved analytical methods and codes. The cycle Core Operating Limit Report provides the cycle-specific core operating parameter. Section 5.0 of the TS references the applicable documents that describe the NRC-approved licensing and analytical methods. Therefore, the licensee can perform the reload analyses and establish the cycle operating parameters under 10 CFR 50.59, because the (1) the required reload analyses are specified in the NRG-approved licensing methodology, and (2) the analyses are performed using NRG-approved analytical methods and the codes. However, any significant changes or modifications to the NRG-approved licensing methodology, analytical methods or codes or the use of a code or analytical method that do not meet the 10 CFR 50.59 criteria would require NRC review and approval, before using these analytical methods or codes to perform the reload safety analyses. A change of SLMCPR constitutes a significant change that requires NRC review and approval.

3.0 TECHNICAL EVALUATION

3.1 HNP, Unit No. 2, Cycle 25 Core HNP, Unit No. 2, is a BWR/4 with two recirculation loops. For Cycle 25, the licensee proposed to change the SLMCPR value in TS Section 2.1.1.2 from 1.09 to 1.10 for two recirculation loop operation, and from 1.12 to 1.13 for single recirculation loop operation. This requirement would be in effect when the reactor vessel steam dome pressure is greater than or equal to 785 pounds per square inch gauge (psig) and the core flow is greater than or equal to 10 percent of rated core flow.

The HNP, Unit No. 2, Cycle 25 core loading will consist of 224 GNF2 and 4 GNF3 fresh fuel bundles, 224 GNF2 once burnt fuel bundles and 108 twice burnt GE14 fuel bundles in the core.

All fuel design types are manufactured by Global Nuclear Fuels-Americas, LLC (GNF).

3.2 Methodology The licensee developed the HNP, Unit No. 2, Cycle 25 SLMCPR values using the following NRG-approved methodologies and uncertainties:

• NEDE-24011-P-A, "General Electric Standard Application for Reactor Fuel (GESTAR II)," November 2015 (including Supplement for United States) (Proprietary information; not publically available). A non-proprietary version titled as NED0-24011-A and supplement are available at ADAMS Accession No. ML15324A144.

NEDC-32505P-A, "R-Factor Calculation Method for GE11, GE12, and GE13 Fuel,"

July 1999 (Proprietary information; not publicly available.). A non-proprietary version titled as NED0-32505-A available at ADAMS Accession No. ML060520636

• NEDC-32601 P-A, "Methodology and Uncertainties for Safety Limit MCPR [minimum critical power ratio] Evaluations," August 1999 (Proprietary information; not publicly available). A non-proprietary version titled as NED0-32601-A and supplement are available at ADAMS Accession No. ML14093A216.

NEDC-32694P-A, "Power Distribution Uncertainties for Safety Limit MCPR Evaluations,"

August 1999 (Proprietary information; not publicly available)

Plant-specific use of these methodologies must adhere to certain restrictions.

3.2.1 Methodology Restrictions Based on the review of Topical Reports (TRs) NEDC-32601 P-A, NEDC-32694P-A, and Amendment 25 to NEDE-24011-P-A (GESTAR II), the NRC staff identified the following restrictions for the use of these TRs:

1. The TGBLA (lattice physics code) fuel rod power calculation uncertainty should be verified when applied to fuel designs not included in the benchmark comparisons of Table 3.1 of NEDC-32601 P, since changes in fuel design can have a significant effect on calculation accuracy.

2. The effect of the correlation of rod power calculation uncertainties should be reevaluated to insure the accuracy of R-Factor uncertainty when the methodology is applied to a new fuel lattice.

3. In view of the importance of Minimum Critical Power Ratio Importance Parameter (MIP) criterion and its potential sensitivity to changes in fuel bundle designs, core loading and operating strategies, the MIP criterion should be reviewed periodically as part of the procedural review process to insure that the specific value recommended in NEDC-32601 P is applicable to future designs and operating strategies.

4. The 3D-MONICORE bundle power calculation uncertainty should be verified when applied to fuel and core designs not included in the benchmark comparisons in Tables 3.1 and 3.2 of NEDC-32694P.

3.2.1.1 Restrictions (1), (2), and (4)

NEDE-24011-P-A provides a fuel design and core reload process that allows licensees to modify fuel assembly designs without undergoing a formal NRC submittal and review, as long as they provide written notification to the NRC outlining the new design and acknowledging compliance with the requirements of NEDE-24011-P-A. On March 14, 2007, GNF sent the NRC the aforementioned notification and generic compliance report for the GNF2 fuel assembly design (ADAMS Accession No. ML070780335). As part of an NRC audit related to this report, the analysis and evaluation of the GNF2 fuel design was verified to have been evaluated in accordance with the above restrictions (ADAMS Accession No. ML082690382). The NRC subsequently issued a finding that upon incorporation of Amendment 33, NEDE-24011-P (ADAMS Accession No. ML102440481) was acceptable for use with the GNF2 fuel design without any restriction.

Based on the above, use of the NEDE-24011-P-A methodology by the licensee is acceptable.

The NRC staff concludes that restrictions (1 ), (2), and (4) to the plant-specific application of the NEDE-24011-P-A methodology have been addressed for the GNF2 fuel design.

3.2.1.2 Restriction (3)

The third restriction in the Safety Evaluation associated with the SLMCPR methodology is more general in that it applies not only to fuel bundle designs but also core configuration. Since it involves the methodology and uncertainty deviations to be discussed in Section 3.3 of this safety evaluation (SE), the evaluation on this restriction is addressed in Section 3.5 of this SE following the evaluation of those deviations.

In summary, the NRC staff concludes that the licensee has adequately addressed the four restrictions of TRs NEDC-32601 P-A, NEDC-32694P-A, Amendment 25 to NEDE-24011-P-A (GESTAR II), and NEDC-32505P-A, and that the use of these TRs to evaluate the HNP, Unit No. 2, Cycle 25 SLMCPR is acceptable.

3.3 Departures from the NRG-Approved Methodology and Uncertainties 3.3.1 R-Factor Uncertainty Due To Channel Bow The R-factor is an input into the GEXL correlation used to describe the local pin-by-pin power distribution and the fuel assembly and channel geometry on the fuel assembly critical power.

The R-factor uncertainty analysis includes an allowance for power peaking modeling uncertainty, manufacturing uncertainty, and channel bow uncertainty. GNF has generically increased the GEXL R-Factor uncertainty to account for an increase in channel bow due to a previously unforeseen phenomenon called control blade shadow corrosion-induced channel bow, which is not accounted for in the channel bow uncertainty component of the approved R-Factor uncertainty, as described in a letter from GNF to the NRC dated November 10, 2004 (ADAMS Accession No. ML043480033).

As a result, the licensee has increased this uncertainty for all SLMCPR calculations to account for the potential impact of control blade shadow corrosion induced bow. The HNP, Unit No. 2, Cycle 25 analysis showed that the expected channel bow uncertainty for HNP, Unit No. 2, is bounded by the increase in R-Factor uncertainty as technically justified in the November 10, 2004, letter.

Thus, the NRC staff concludes that the use of the higher GEXL R-Factor uncertainty described in the November 10, 2004, letter adequately accounts for the expected control blade shadow corrosion-induced channel bow for HNP, Unit No. 2, Cycle 25.

3.3.2 Core Flow Rate and Random Effective Traverse In-core Probe (TIP) Reading GNF agreed to expand the state points used in the determination of the SLMCPR as described in a GE Nuclear Energy letter dated August 24, 2004 (ADAMS Accession No. ML042720293).

Consistent with the August 24, 2004, letter, the applicant performs analyses at the rated core power and minimum licensed core flow point in addition to analyses at the rated core power and rated core flow point. The NRG-approved SLMCPR methodology is applied at each state point.

For two-loop operation calculations performed at 92.9 percent of rated core flow, the NRG-approved uncertainty values for the core flow rate (2.5 percent) and the random effective TIP reading (1.2 percent) are adjusted by dividing them by 0.929. The treatment of the core flow and random effective TIP reading uncertainties is based on the assumption that the

signal-to-noise ratio deteriorates as core flow is reduced. The licensee stated that this increase is conservative based on the expectation that the variability in the absolute flow will decrease as flow decreases.

The core flow and random TIP reading uncertainties used in single-loop operation minimum core flow SLMCPR analysis remain the same as in the rated core flow SLMCPR analysis because these uncertainties (which are substantially larger than used in two-loop operation analysis) already account for the effects of operating at reduced core flow.

Since the increase in the uncertainty described above bounds the original non-flow dependent uncertainties, the NRC staff concludes that it is acceptable for HNP, Unit No. 2, Cycle 25.

3.3.3 Fuel Axial Power Shape Penalty The GEXL correlation critical power uncertainty and bias are established for each fuel product line according to a process described in NEDE-24011-P-A. GNF determined that higher uncertainties and non-conservative biases in the GEXL correlations for certain types of axial power shapes could exist relative to the NRG-approved methodology values. The GE14 and GNF2 product lines are potentially affected in this manner only by Double-Hump (D-H) axial power shapes. The GNF3 lead use assemblies (LUAs) in this core analysis are using the same GEXL correlation as GNF2, and therefore, the same axial power shape biases apply.

The D-H axial shape did not occur on any of the limiting bundles (i.e., those contributing to the 0.1 percent rods susceptible to transition boiling) in the current and/or prior cycle limiting cases.

Therefore, D-H power shape penalties were not applied to the GEXL critical power uncertainty or bias.

The licensee determined that none of the limiting bundles had one of these types of axial power shapes. Therefore, no power shape penalties were applied to the calculated HNP, Unit No. 2, Cycle 25 SLMCPR values. This approach is consistent with prior precedent for NRC approval of SLMCPR license amendment request submittals using the NEDE-24011-P-A methodology.

The NRC staff concludes that the licensee adequately considered the potential for a higher SLMCPR value resulting from non-conservatisms in the GEXL correlation due to certain axial power shapes within limiting bundles. Therefore, the use of no axial power shape penalties is acceptable.

3.3.4 Flow Area Uncertainty GNF calculated the flow area uncertainty for GNF2 and GE14 using the process described in Section 2.7 of NEDC-32601P-A. The flow area uncertainty for GNF2 and GE14 is conservatively set by a bounding value. Because this bounding value is larger than the value approved in NEDC-32601 P-A, the bounding value was used in the SLMCPR calculations.

The flow area uncertainty applied to the GNF3 LUAs in this core analysis is the same as used for GNF2 and GE14. This is acceptable because the GNF3 LUAs are in core locations that are not limiting in the MCPR and are not contributing to the SLMCPR calculation. Therefore, small inaccuracies in the flow area uncertainty would not significantly affect the limiting SLMCPR.

The NRC staff concludes that the channel flow area uncertainty value applied to both GNF2 and GE14 fuels conservatively bounds the reference value when utilizing the same calculation methodology. Therefore, the proposed SLMCPR limits adequately address the uncertainties in channel flow areas for the GE14 and GNF2 fuel designs.

3.4 Evaluation of Restriction (3)

Restriction (3) states that the MIP criterion should be reviewed periodically as part of the procedural review process to insure that the specific value recommended in NEDC-32601 P is applicable to future designs and operating strategies. The NRC staff evaluated the licensee's response to Restriction (3) by taking into account (1) the factors discussed in Section 3.3 of this safety evaluation that affect the evaluation of Restriction (3); (2) the use of 92.9 percent of rated flow, and (3) the number of CNF 2 fuel bundles.

In Section 3.3, of this safety evaluation, the NRC staff reviewed the factors that affect the MIP, which are the R-factor (Section 3.3.1 ), core flow rate (Section 3.3.2 and 3.3.4) and random effective TIP reading (Section 3.3.2). As stated in each of those sections, the NRC staff finds that these factors are acceptable for use by the licensee.

Table 1 of GNF-003N7688-R1-P, "GNF Additional Information Regarding the Requested Changes to the Technical Specification SLMCPR," (proprietary information; not publically available) showed that the state point used in the determination of Cycle 25 SLMCPR for two recirculation loop operation would be the minimum core flow at rated core power instead of the rated core flow at rated core power that was used in Cycle 24. The NRC staff has found that the use of 92.9 percent of rated flow as the minimum flow for HNP, Unit No. 2, Cycle 25 is consistent with the analysis of record (i.e. Section 4.4.3.3, "Power-To-Flow Map," of HNP, Unit No. 2, Updated Final Safety Analysis Report Rev. 34).

In comparison with Cycle 24, more GNF2 fuel bundles than GE14 fuel bundles will be used in the Cycle 25 core. Since the critical power correlation uncertainty for GNF2 is higher than GE14's, the NRC staff finds that the Cycle 25 SLMCPR would be higher than in Cycle 24 and the proposed TS 2.1.1.2 changes are consistent with this determination.

Based on the review of the HNP, Unit No. 2, application and associated references, the NRC staff has determined that SNC has used appropriate vendor specific methodologies and assumptions for determination of the SLMCPR values for Cycle 25. These methodologies and assumptions are consistent with previous applications associated with determining SLMCPR values for the specific fuel utilized by HNP, Unit No. 2 in Cycle 25. Therefore, the NRC staff concludes that Restriction (3) has been addressed.

3.5 Rounding of the Single Recirculation Loop Monte Carlo Result The proposed SLMCPRs of 1.10 for two recirculation loop operation and 1.13 for single recirculation loop operation are based on Monte Carlo calculated results. The single recirculation loop MCPR value, 1.13, is a non-conservative rounded value from a Monte Carlo calculated value. In the supplement dated November 18, 2016, the licensee stated that the rounded value is based on standard rounding practices (i.e., to two places past the decimal point). The NRC staff reviewed the rounding method for the single recirculation loop MCPR value. The licensee's degree of rounding is less than the level of significance established as

part of the NRG-approved methodology in topical report NEDC-33173P-A, "Applicability of GE Methods to Expanded Operating Domains," (proprietary information; not publicly available).

Although the round off process is in a non-conservative direction, the NRC staff has determined that there is no safety significance with the round off when considering the inherent variability of the Monte Carlo process used to establish the SLMCPR values. Based on the use of NEDC-33173P-A and the volatility of the Monte Carlo process, the NRC staff finds the non-conservative rounding of the single recirculation loop MCPR value for HNP, Unit No. 2, for Cycle 25 to be acceptable.

3.6 Summary The licensee's proposed Cycle 25 SLMC(PR values of 1.10 for two recirculation loop operation and 1.13 for single recirculation loop operation were developed through the appropriate use of NRG-approved methodologies and meet the requirements of 10 CFR)50.36(c)(1 )(i)(A) and GDC 10. Therefore, the NRC staff concludes that the SLMCPR values are acceptable for HNP, Unit No. 2, Cycle 25.

4.0 STATE CONSULTATION

In accordance with the Commission's regulations, the Georgia State official was notified of the proposed issuance of the amendments on December 9, 2016. The State official had no comments.

5.0 ENVIRONMENTAL CONSIDERATION

The amendment changes a requirement with respect to the installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20. 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 amendment involves no significant hazards considerations, and there has been no public comment on the finding (81 FR 70184, October 11, 2016). Accordingly, the amendment meets 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 Contributor: S. Peng Date:

part of the NRG-approved methodology in topical report NEDC-33173P-A, "Applicability of GE Methods to Expanded Operating Domains," (proprietary information; not publicly available).

Although the round off process is in a non-conservative direction, the NRC staff has determined that there is no safety significance with the round off when considering the inherent variability of the Monte Carlo process used to establish the SLMCPR values. Based on the use of NEDC-33173P-A and the volatility of the Monte Carlo process, the NRC staff finds the non-conservative rounding of the single recirculation loop MCPR value for HNP, Unit No. 2, for Cycle 25 to be acceptable.

3.6 Summary The licensee's proposed Cycle 25 SLMCPR values of 1.10 for two recirculation loop operation and 1.13 for single recirculation loop operation were developed through the appropriate use of NRG-approved methodologies and meet the requirements of 10 CFR)50.36(c)(1 )(i)(A) and GDC 10. Therefore, the NRC staff concludes that the SLMCPR values are acceptable for HNP, Unit No. 2, Cycle 25.

4.0 STATE CONSULTATION

In accordance with the Commission's regulations, the Georgia State official was notified of the proposed issuance of the amendments on December 9, 2016. The State official had no comments.

5.0 ENVIRONMENTAL CONSIDERATION

The amendment changes a requirement with respect to the installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20. 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 amendment involves no significant hazards considerations, and there has been no public comment on the finding (81 FR 70184, October 11, 2016). Accordingly, the amendment meets 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 Contributor: S. Peng Date: January 6, 2017

January 6, 2017 Mr. C. R. Pierce Regulatory Affairs Director Southern Nuclear Operating Company, Inc.

Post Office Box 1295, Bin - 038 Birmingham, AL 35201-1295

SUBJECT:

EDWIN I. HATCH NUCLEAR PLANT, UNIT NO. 2, ISSUANCE OF AMENDMENT REGARDING MINIMUM CRITICAL POWER RATIO (CAC NO. MF8309)

Dear Mr. Pierce:

The U.S. Nuclear Regulatory Commission has issued the enclosed Amendment No. 226 to Renewed Facility Operating License NPF-5 for the Edwin I. Hatch Nuclear Plant, Unit No. 2, in response to the license amendment application dated August 29, 2016, as supplemented by letter dated November 18, 2016. The amendment revises the Technical Specification value of the Safety Limit Minimum Critical Power Ratio to support operation in the next fuel cycle.

A copy of the related Safety Evaluation is also enclosed. A Notice of Issuance will be included in the Commission's biweekly Federal Register notice.

Sincerely, IRA!

Michael Orenak, Project Manager Plant Licensing Branch 11-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-366

Enclosures:

1. Amendment No. 226 to NPF-5

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

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OFFICE NRR/LPL2-1/PM NRR/LPL2-1/LA DSS/SRXB/BC NRR/DSS/STSB/BC NAME MOrenak KGoldstein EOesterle AKlein DATE 12/19/16 12/29/16 12/1/16 12/22/16 OFFICE OGC N RR/LPL2-1 /BC NRR/LPL2-1/PM NAME STurk MMarkley MOrenak DATE 12/28/16 01/06/17 01/06/17 OFFICIAL RECORD COPY