RBG-43608, Application for Amend to License NPF-47,to Enhance Operation of Plant,Thereby Yielding Economic Benefit to RBS Through Extended Power production.NEDC-32611P Encl.Rept Withheld

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Application for Amend to License NPF-47,to Enhance Operation of Plant,Thereby Yielding Economic Benefit to RBS Through Extended Power production.NEDC-32611P Encl.Rept Withheld
ML20134A698
Person / Time
Site: River Bend Entergy icon.png
Issue date: 01/20/1997
From: Mcgaha J
ENTERGY OPERATIONS, INC.
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML19355E516 List:
References
RBEXEC-97-005, RBEXEC-97-5, RBF1-97-0004, RBF1-97-4, RBG-43608, NUDOCS 9701290050
Download: ML20134A698 (14)
v • d • e


Text

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Entergy operations,Inc. '

9 R ver Bend Stabon 5485 U S Highway 31 RO. Box 220 l

I i] g St. Francisville. LA 70775 Tel 504 3814374 Fax 504 3814872 John R. McGaha, Jr.

Vice Presdent Operations January 20,1997 U. S. Nuclear Regulatory Commission Document Control Desk Mail Station Pl-37 Washington, DC 20555

Subject:

River Bend Station - Unit 1 Docket No. 50-458 License No. NPF-47 License Amendment Request (LAR) 96-54, Maximum Extended Load Line Limit Analysis File Nos.: G9.5, G9.42 i i

l RBEXEC-97-005 i RBF1-97-0004 RBG-43608 Gentlemen:

In accordance with 10 CFR 50.90, Entergy Operations, Inc. (EOI) hereby applies for -

amendment of Facility Operating License No. NPF-47, Appendix A - Technical Specifications, for River Bend Station (RBS). The proposed change is to Technical Specifications Table 3.3.1.1-1," Reactor Protection System Instrumentation," and LCO 3.4.1, "Recirulation Loops Operating."

This change request will enhance the operation of the plant, thereby yielding economic benefit to RBS through extended power production. The request allows operation at 100% power l with lower core flows and the use of flow control spectral shift strategies to increase cycle energy. Based on the Cycle 7 energy projection, it is estimated that 30 additional days at full power would be available if this change were implemented. RBS plans to utilize the flow control spectral shift mode of operation in Cycle 8 begining October 1997 and it will be factored into the core design, fuel reload safety analysis and power performance planning. 1 This improvement has been licensed for the other BWR6 plants in the United States.

Therefore, it is requested this change be approved in time to support startup from the next refueling outage, scheduled to begin September 12,1997. ,

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License Amendment Request (LAR) 96-54, Maximum Extended Load Line Limit Analysis January 20,1997 l RBEXEC-97-005 RBF1-97-0004 RBG-43608 Page 2 of 3 i

Based on the guidelines in 10 CFR 50.92, Entergy Operations has concluded that this proposed amendment involves no significant hazards considerations. Attachment 2 provides I the basis for this determination in a detailed description of the proposed changes, a justification for the proposed changes and the No Significant Hazards Considerations.

Attachment 3 is a copy of the marked-up TS pages.

Attachment 4 is the General Electric (GE) report NEDC-32611P," Maximum Extended Load Line Limit Analyses For River Bend Station Reload 6 Cycle 7," Revision 0, dated November 1996. This report contains the plant specific safety analysis prepared by GE in support of this change to the RBS license. Attachment 4 contains information proprietary to GE. GE requests that the documents be withheld from public disclosure in accordance with 10 CFR 2.790 (a) (4). The affidavits supporting this request in accordance with 10 CFR 2.790 (a) (4),

are provided with attachment 4.

This request has been discussed with the NRR project manager for RBS. It has also been reviewed and approved by the RBS Facility Review Committee and the Nuclear Review Board. If you have any questions regarding this request or require additional information, please contact Mr. T. W. Gates at (504) 381-4866.

Sincerely, JRM/RJK/BMB/kvm attachments

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License Amendment Request (LAR) 96-54, Maximum Extended Load Line Limit Analysis January 20,1997 IGEXEC-97-005 IGF1-97-0004 RBG-43608 Page 3 of 3.

cc: Mr. David L. Wigginton U. S. Nuclear Regulatory Commission M/S OWFN 13-H-15

. Washington, DC 20555 NRC Resident Inspector P. O. Box 1050 St. Francisville, LA 70775 U. S. Nuclear Regulatory Commission Region IV '

611 Ryan Plaza Drive, Suite 400 -

Arlington, TX 70611 '  :

Department of Environmental Quality l Radiation Protection Division  !

P. O. Box 82135  :

Baton Rouge, LA 70884-2135 '

Attn: Administrator i

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i 4- j

BEFORE Tile UNITED STATES NUCLEAR REGULATORY COMMISSION LICENSE NO. NPF-47 IN THE MATTER OF ENTERGY GULF STATES, INC.

CAJUN ELECTRIC POWER COOPERATIVE AND ENTERGY OPERATIONS, INC.

AFFIRMATION I, John R. McGaha, state that I am Vice President-Operations of Entergy Operations, Inc., at River Bend Station; that on behalf of Entergy Operations, Inc., I am authorized by Entergy Operations, Inc., to sign and file with the Nuclear Regulatory Commission, this River Bend Station License Amendment Request (LAR) 96-54, Change to Technical Specifications concerning the " Maximum Extended Load Line Limit Analysis;" that I signed this letter as Vice President-Operations at River Bend Station of Entergy Operations, Inc.; and that the statements made and the matters set forth therein are true and correct to the best of my knowledge, information, and belief.

ohn R. McGaha STATE OF LOUISIANA PARISH OF WEST FELICIANA SUBSCRIBED AND SWORN TO before me, a Notary Public, commissioned in the Parish above named, this JOO day of O Raut anu 1997.

O j (SEAL) 0lLudh Q h vit Claudia F. IIurst Notary Public My Commission expires with life e __ __

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ATTACIIMENT 2 ENTERGY OPERATIONS INCORPORATED RIVER BEND STATION l DOCKET 50-458/ LICENSE NO. NPF-47 i Maximum Extended Load Line Limit Analysis 1 l

(LAR 96-54) l 1

DOCUMENT INVOLVED I

Technical Specifications: Table 3.3.1.1-1, Reactor Protection System Instrumentation j LCO 3.4.1, Recirculation Loops Operating

Background

The RBS power / flow operating regions, described in the Safety Analysis Report (USAR)

~ Chapter 4, section 4.4.3.3, provide the basic operating envelope within which normal reactor operations are conducted. The current operating power / flow map is bounded by the 105% rod line, rated power line and the 107% core flow line. The proposed Maximum Extended Load Line Limit (MELLL) operation mode and the associated Technical Specification changes expand the operating domain along the 121% rod line to the power / flow point of 100% power and 75%

core flow. These limits continue to meet the necessary safety margins including thermal and reactivity limits. The technical analysis is referred to as the MELLL analysis and the defined domain is referred to as the MELLL region.

An enlarged power / flow map for RBS permits improved power ascension capability by extending plant operation at rated power with less than rated core flow during the fuel cycle.

Operation in the MELLL region domain enhances plant operational flexibility and increases plant capacity factor, thereby yielding economic benefit to RBS through extended power production. The MELLL allows operation at 100% power with core flows as low as 75% and the use of flow control spectral shift strategies to increase cycle energy. Based on the Cycle 7 energy projection, it is estimated that 30 additional days at full power would be available if this change were implemented. RBS plans to utilize the flow control spectral shift mode of operation in Cycle 8 scheduled to begin October 1997 and it will be factored into the core design, fuel reload safety analysis and power performance planning. This improvement has been licensed for the other BWR6's in the United States (Grand Gulf Nuclear Station, Perry Nuclear Power Plant and Clinton Power Station).

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The Maximum Extended Operating Domain (MEOD) is a GE BWR6 performance improvement 4 program as described in GESTAR-Il (US supplement section S.5.2.7 Reference 4). The MEOD improvement package includes MELLL, Increased Core Flow (ICF) and T-Factor Setdown Elimination to achieve optimal core operational flexibility.

Operation in the increased core flow region, up to 107% rated flow, was previously implemented late in Cycle 6. The T-Factor Setdown Elimination has been submitted for RBS under a separate license amendment request, Reference 2. The T-factor elimination request proposed revised operating limit Minimum Critical Power Ratio (MCPR) and flow dependent Linear Heat j Generation Rate (LHGR) limits to ensure acceptable thermal margin for power operation. In addition to the MEOD improvements identified above, other performance enhancements ,

previously approved for RBS in license amendments No. 37 for non-cycle-extension Feedwater Heater Out of Service (FWHOS) and No. 31 for Single Loop Operation (SLO) were also considered in the MELLL analyses.  ;

l The General Electric (GE) analysis which supports this request and the changes to the Technical Specifications are included in GE report NEDC-32611P (Attachment 4). In addition to the fuel protection limits, additional evaluations were conducted to ensure acceptable margins were  !

maintained for other issues associated with operation in the MELLL region. These evaluations )

addressed: ATWS, stability, vessel overpressure, containment vessel overprotection and reactor internals. This report shows that RBS can operate within the extended MELLL regions while continuing to support required safety margins.

The limiting anticipated operational occurrences (AOOs) and fuel-dependent events for the MELLL region were examined to ensure the operating limit minimum critical power ratio (OLMCPR) will continue to defend the safety limit minimum critical power ratio (SLMCPR).

These analyses show that the OLMCPR for operation in the MELLL region remains bounded by the OLMCPR established for current rated conditions of 100% power and 107% flow. The power and flow dependent thermal limits (MCPR-f, MCPR-p) for the current operating cycle were used in this analysis. Operation within these limits ensures that the consequences of the analyzed AOOs and accidents are acceptable.

This request for operation in the MELLL region is not dependent on the SLMCPR revision Technical Specification change (Reference 5). The changes to the OLMCPR and associated MCPR-p and MCPR-flimits have been previously implemented. This early implementation was acceptable because the changes necessary for SLMCPR are conservative to the current specified limits.

The T-factor elimination is a less restrictive initial condition for the MELLL analysis therefore, this request for operation in the MELLL region is not dependent on the implementation of the T-Factor Setdown Elimination. The T-factor elimination conditions were also confirmed to be acceptable in this analysis. The T-Factor elimination is desirable from an operational point of view for operating flexibility. With the approval of the T-Factor elimination request, changes to the MCPR-p, MCPR-f, LHGR-p and LHGR-flimits will replace LCO 3.2.4 and will continue to provide sufficient protection for fuel integrity.

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The average power range monitors (APRM) setpoints are revised as shown in the marked-up changes in Attachment 3 to allow operation in the region defined by the MELLL. APRM flow biased rod block and scram are not credited in GE safety analyses. No hardware change is necessary for this change, and existing RBS procedures will be used to adjust these setpoints to their MEL.LL values. These limits, contained in the Core Operating Limits Report (COLR), will be verified and adjusted as necessary for future cycles.

ANALYSIS RESULTS Each of the limiting AOOs was analyzed for the MELLL region. These limiting core-wide AOOs include: Pressure Regulator Failure Downscale (PRFDS), Generator Load Rejection with No Bypass (LRNBP), Feedwater Controller Failure maximum demand (FWCF), and Fuel Loading Error (FLE) event. These events were examined for impact on the OLMCPR when operating in the MELLL region. For the fuel-dependent evaluations of reactor pressurization events, these analyses show that the OLMCPR for operation in the MELLL region remains bounded by the current rated conditions. For non-pressurization events, the Fuel Loading Error-Mislocated Bundle is the limiting event at rated conditions for GE8 fuel. The power and flow dependent thermal limits (MCPR-f, MCPR-p) for the current operating cycle (Cyciq,7) were used in this analysis. These limits will be verified and adjusted as necessary for future cycles.

~ Operation within these limits ensures that the consequences of all AOOs and accidents are acceptable.

The APRM setpoints are revised as shown in the marked-up changes in Attachment 3 to allow operation in the region defined by the MELLL. With the revised setpoints, the APRM's continue to maintain margins to thermal limits. No other hardware change is necessary and existing RBS procedures will be used to adjust these setpoint to their MELLL values. General Electric (GE) has provided the necessary safety analyses, system analysis and feasibility analysis which supports the requested changes to the Technical Specifications. This report shows that RBS can operate within the extended regions bounded by the rod line which passes through the 100%

power /75% core flow point (approximately 121% rod line), the rated power line and the 107%

rated flow line. The effect of operating with MELLL during SLO will change specification 3.4.1 to identify a new power limit of 83% to restrict operation within the analyzed region.

The proposed changes to RBS Technical Specifications are based on the GE report NEDC-3261IP provided as Attachment 4 of this submittal. Thejustifications for MELLL operation provided by these analyses are summarized below.

Anticipated Operational Occurrences (AOO) Analyses The effects of various transient events were analyzed to ensure that the proposed expansion of the power / flow region of USAR Chapter 4 (section 4.4.3.3) described above will maintain adequate margins. This margin is assured when the results of an event are maintained above the fuel cladding integrity Safety Limit MCPR. Maintaining this limit assures that 99.9 Page 3 of 10 e  ;

percent of the fuel rods are expected to avoid boiling transition. The change in CPR of an event is added to the SLMCPR to obtain the OLMCPR. The events analyzed are consistent with the Cycle 7 reload analysis (Reference 3) and the standard MELLL evaluation identified in GESTAR-II, section S.5.2.7. This analysis includes the core wide rapid pressurization events of: PRFDS, described in USAR Section 15.2; LRNBP, described in USAR Section 15.2; and FWCF, described in USAR Section 15.1. Although not considered a limiting event, the Pressure Regulator Failure (PRFDS) event was also analyzed to verify that it will not become limiting for operation in the MELLL region. The results of this analysis indicates the LRNBP remains the most limiting in the MELLL region for gel 1 fuel. FWCF is also the limiting event with FWIlOS as described in USAR section 15.1.7.

Analysis has concluded that operation in the MELLL region is bounded by the current Cycle .

7 OLMCPR in the RBS Cycle 7 COLR. Use of the operating limits currently set forth in the l COLR and the Technical Specification T-Factor Setdown requirements (LCO 3.2.4) will ensure that operation is within the MCPR safety limits and the fuel cladding 1% plastic strain limit in all power / flow regions. Upon approval and implementation of the T-Factor Setdown Elimination (RBG-43161), the T-Factor setdown requirements (LCO 3.2.4) will be replaced by the flow and power dependent LIIGR limit. Ilowever, the implementation of the T-Factor Setdown Elimination before the MELLL is only desirable from an operational point of view and not a requirement for implementation of MEuuL. In addition, ,

applicability of the OLMCPR in future fuel cycles will be verified on a cycle-specific basis.

These limits, which are contained in the COLR, will be verified and adjusted as necessary for future cycles.

Thermal-Hydraulic Stability RBS has implemented the GE Service Information Letter (SIL) 380, Revision 1, "BWR Core Thermal llydraulic Stability," recommendations. RBS is also in compliance with the interim measures of USNRC Bulletin 88-07, Supplement 1, " Power Oscillations in Boiling Water Reactors (BWRs)." In addition, core / channel decay ratio as well as the stability exclusion region are reanalyzed for new fuel designs to demonstrate stability performance.

In addition to the measures taken in response to the GE SIL and the USNRC Bulletin, RBS is expecting to implement additional protection to limit the likelihood and effects of a stability condition. These efforts include the implementation of option IA included in the ,

BWROG topical report, NEDO-32339-A, " Reactor Stability Long-Term Solutions:

Enhanced Option I-A." The implementation of these measures is currently scheduled for late 1997 (after RF7), as identified in the RBS response to USNRC Generic Letter 94-02 (RBG-40869, dated September 12,1994).

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Other impact Evaluations Single Loop Operation (SLO) analyses were reviewed to ensure their applicability in the MELLL region. The maximum power / flow state point achievable with one recirculation pump operation is 83% power /54% flow. Technical Specification 3.4.1 will be changed to identify this new power limit of 83% and therefore to restrict operation within the analyzed region. The remaining restrictions, including the maximum recirculation loop flow rate of 33,000 gpm, will continue to be applicable to plant operation in the MELLL domain and will be confirmed for each fuel cycle. These limits, which are contained in the COLR and supplemental reload licensing report, will be verified and adjusted as necessary for future cycles.

The Control Rod Drop Accident results for Cycle 7, the Cycle 7 Fuel Loading Error results and the Loss of Feedwater Heating transient are applicable to operation in the MELLL domain. The most important parameters affecting the Rod Withdrawal Error (initial control rod pattern and rod position) are not affected by the operation in the MELLL region.

Therefore, for these events, previous analyses remain valid for operation in the MELLL region.

The current ATWS analysis performed for RBS was reviewed and it was determined there is no impact on the plant systems required to mitigate postulated ATWS events in the expanded operating region.

Loss-of-Coolant Accident (LOCA) Analysis Operation at a higher core power and lower core flow condition, relative to the current power /ilow region, results in an earlier boiling transient and slightly increases the Peak Clad Temperature (PCT). An ECCS-LOCA analysis was conducted to determine the impact of MELLL operation on the RBS LOCA analysis PCT. The result was an estimated change of l less than 5 F from the value for operation in the currently approved power / flow regime.

This evaluation was conducted using the current RBS licensing basis method SAFE /REFLOOD as described in GESTAR-II section S.2.2.3.2 (Reference 4).

Prior to implementation of MELLL in Cycle 8, EOl will ensure adequate PCT margin exists to absorb this small additional impact. RBS expects to have implemented the newer GE SAFER /GESTR code before the end of Cycle 7. The methodology improvements in GE SAFER /GESTR are expected to result in several hundred degrees ci thermal margin to 10 CFR 50.46 PCT limits. The preliminary SAFER /GESTR analyses, conducted with inputs which bound both cycle 7 and 8, have resulted in a PCT of about 1300 F. This result is well within the guidance recommended by the NRC in the safety evaluation report on the use of SAFER /GESTR. With MELLL scheduled to be implemented prior to startup for Cycle 8, the increased PCT will not affect compliance with safety limits after y implementation of the SAFER /GESTR ECCS analysis methodology. Potential avenues also j exist for revising the current SAFE /REFLOOD calculations to ensure compliance with PCT i l

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limits while supporting MELLL implementation. These include revising assumptions J l concerning MAPLHGR limits, initial MCPR, or performing additional plant specific PCT l

j. calculations.

l l Containment Response 1

Bounding short-tenn containment response analyses of the design basis LOCA event were l ' performed to demonstrate that operation in the MELLL domain will not result in exceeding j containment design limits. The SAR steamline break analysis is applicable to the MELLL

! conditions. The analysis performed for implementation of MELLL determined that there is i no change in the steam conditions in the reactor steam dome and therefore the containment analysis remains unchanged for operation in the MELLL region. Therefore, the analysis

results in SAR section 6.2 for steamline break remain valid in the MELLL region.

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! The recirculation line break in the MELLL region was analyzed to show that the drywell-l wetwell pressure differential response remains well below the design value of 25 psid. The

drywell airspace temperature is within the current recirculation line break analysis results in a

the SAR. In addition, it was concluded that operation under MELLL conditions will not significantly affect containment dynamic loads. Any resulting increase in current containment dynamic loads is judged to be acceptable due to the existing conservatism in the 1 design margin.  !

i Vessel Overpressure Protection The Main Steam Isolation Valve (MSIV) closure event was re-analyzed as described in SAR section 15.2.4 and demonstrated conformance to the ASME code in the MELLL region. The results of this analysis confirmed that the peak pressure of 1295 psig for MELLL operation i is bounded by the current Cycle 7 result of 1311 psig.

I ReactorInternals Integrity \

l An evaluation was performed to identify potential increases in reactor internal pressure differences (RIPDs). This evaluation shows that the RIPDs for MELLL conditions resulting from recirculation pump runout are bounded by the current design basis results for the upset  !

condition. Therefore, it has been concluded that RBS can operate in the MELLL region without any detrimental effects on the reactor intemals due to flow induced vibration.

CONCLUSION EOI has performed the analyses necessary for implementation of MELLL using current cycle limits to determine the impact of operation in the MELLL region as part of an ongoing program of MEOD improvements. No significant issues have emerged from the analyses that would create a barrier to operation in the MELLL region. The impact on PCT will be addressed prior to implementation to ensure that the PCT limit of 10 CFR .'0.46 will be satisfied. Based on our Page 6 of 10

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analysis, operation in the MELLL region will be acceptable. Operation in the MELLL region does not introduce a significant change in the response of the plant to an event and the required

margins will be maintained. The changes necessary for implementation of the request are l described below. As discussed above, the cycle-to-cycle limits will be submitted to the NRC in
' the COLR in accordance with Operating License section 5.6.5 and will be verified and adjusted i

as necessary for future cycles. .

PROPOSED CIIANGES ,

To implement this request, changes will be required to the APRM flow-biased scram and rod block limits. The T-Factor setdown elimination is desirable from an operational point of view l but is not required for MELLL to be implemented. The necessary TS changes are desenbed in l l Attachment 3.

In addition to the required Technical Specification changes, the following Technical Requirements Manual and BASES changes will be made in support of this request in accordance with 10CFR50.59. The table below summarizes the changes necessary and is provided for information:

l TRM Sections Current Values Proposed Changes TSR 3.4.1.1.2, page TR 3.4-3 Verify TilERMAL POWER is 5 Verify THERMAL POWER is 5 70% RTP 83% RTP Table 3.3.2.1-1, Function 5.a.1, page Nominal Setpoint: .66W + 42 % Nominal setpoint: .66W + 58 %

TR 3.3-10 RTP RTP Table 3.3.2.1-1, Function 5.a.1, page Allowable Value: .66W + 45 % Allowable Value: .66W + 61 % RTP TR 3.3-10 RTP Table 3.3.2.1-1, Function 5.a.2, page Nominal Setpoint: .66W + 36.7 % Nominal setpoint: .66W + 52 %

TR 3.310 RTP RTP Table 3.3.2.1-1, function 5.a.2, page Allowable Value: .66W + 39.7 % Allowable Value: .66W + 55 % RTP TR 3.3-10 RTP Table 3.3.1.1-1, function 2.b, page 0.66W + 48% RTP and i 11% RTP 0.66W + 64% RTP and 111% RTP TR 3.3-2 Table 3.3.1.1-1, Footnote (b), page Nominal setpoint is 0.66 W + 42.7% Nominal setpoint is 0.66 W + $8%

TR 3.3-2 RTP when reset for single loop RTP when reset for single loop operation per LCO 3.4.1, operation per LCO 3.4.1,

" Recirculation Loops Operating." " Recirculation Loops Operating."

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BASES Current Value Proposed changes LCO, page B3.4-3 70% RTP 83% RTP ACTION B.1, page B3.4-5 70% RTP 83% RTP In addition, related SAR sections including Chapter 4,6 and 15 will be revised in accordance with RBS procedures.

ENVIRONMENTAL IMPACT CONSIDERATION EOI has reviewed this request against the criteria of 10CFR51.22 for environmental considerations. Since this request involves (i) no significant hazard consideration, (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, EOI has concluded that the proposed change meets the criteria given in 10CFR51.22 (c)(9) for a categorical exclusion from the requirement for an environmental impact statement.

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NO SIGNIFICANT IIAZARDS CONSIDERATION

1. The proposed changes do not significantly increase the probability or consequences of an accident previously evaluated.

Abnormal operational transients or accidents analyzed in the SAR have been examined for any impact caused by MELLL operation. The limiting abnormal operation transients, including the Generator Load Rejection with No Bypr.ss (LRNBP) event and the Feedwater Controller Failure (FWCF) maximum demand event, have been evaluated in detail. The LOCA, Fuel Loading Error (FLE), rod drop accident, rod withdrawal error, and the Anticipated Transient Without Scram (ATWS) analyses have also been evaluated for the effects of MELLL operation. The flow and power dependent MCPR curves for otT-rated and rated conditions and the MAPLHGR criteria establish limits on power operation. These limits ensure that the core is operated within the assumptions and initial conditions of the transient or accident analyses. Operation within these limits will ensure that the consequences of a transient or accident remain within the acceptable limits of the analyses.

The APRM scram in the Technicel Specifications and affected rod block setpoints are revised to ensure that operation remains within the analyzed MELLL region. This  ;

restriction ensures the consequences of abnormal operation and accidents are acceptable. j The probability of an accident is not affected by the proposed Technical Specification I changes since no systems or eqtiipment which could initiate an accident are affected. l

, Therefore, the proposed changes do not significantly increase the probability or consequences of any previously evaluated accident. )

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, 2. The request does not create the possibility of occurrence of a new or different kind of accident from any accident previously evaluated.

Operation in the MELLL domain expands the current power / flow along the 121% rod line to 100% power at 75% rated core flow and improves flexibility and capacity factor. Abnormal operation transients or accidents have been evaluated and the most limiting cases have been analyzed for applicability for operation in the MELLL region. The proposed Technical Specification changes prohibit power operation outside the MELLL region and do not constitute or require any system or equipment changes that might create an accident of a different type then previously evaluated. The MAPLHGR, the power and flow dependent MCPR and LHGR and the revised Technical Specifications will continue to assure that plant operation is consistent with the assumptions, initial conditions and assumed power distribution and therefore will not create a new type of accident. The proposed Technical Specification changes do not introduce any new modes of plant operation nor involve new system interactions. Therefore, the proposed changes do not create the possibility of a new or different kind of accident from any previous analyzed.

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3. The request does not involve a significant reduction in a margin of safety.

The proposed Technical Specifications prohibit power operation outside the allowable MELLL region. The transients and accidents described in the SAR are evaluated for operation in the MELLL region. NEDC-3261IP,"MELLL Analysis for River Bend Station '

Reload 6 Cycle 7," shows that the OLMCPR for operation in the MELLL region is bounded j by the OLMCPR established for current conditions (100% power /107% flow). The thermal ,

limits MCPR and LHGR curves and the MAPLHGR limits establish limits on power operation and thereby ensure that the core is operated within the assumptions and initial conditions of the transient and accident analyses.-

As demonstrated in the analysis provided in Attachment 4, operation within these limits,  !

using the MCPR limits, LHGR limits and MAPLHOR criteria, will ensure that the margin of safety will be maintained to the same level described in the Technical Specifications Bases and the SAR and the consequences of the postulated transient or accidents are not increased. l The MCPR safety limit, mechanical performance limits and overpressure limit are not l

exceeded during any transient or postulated accident. Therefore, the proposed Technical Specifications to allow operation in the MELLL region do not involve a significant reduction in margin of safety. - '

On this basis,it is concluded that: (1) the proposed changB does not constitute a significant hazards consideration as defined by 10CFR50.92; (2) there is a reasonable assurance that the 1 health and safety of the public will not be endangered by the proposed change; and (3) this action will not result in a condition which significantly alters the impact of the station on the environment as described in the NRC final environmental statement.

REFERENCES

1. Amendment No. 31 " Single Loop Operation" and Amendment No. 37 "Feedwater Heater Out of Service."
2. T-Factor Setdown Elimination; LAR 96-23, RBG-43161 dated August 29,1996.
3. Supplemental Reload Licensing Report for River Bend Station Reload 6 (Cycle 7), General Electric report 24A5188 Rev. 2,.
4. General Electric Standard Application for Reactor Fuel (GESTAR-II), NEDE-20411-P-A.
5. Safety Limit /CPR Change, LAR 96-42, RBG-43326 dated November 15,1996.

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