ML060400599

License Amendments, Activation of the Trip-Outputs of the Oscillation Power Range Monitor System

ML060400599
Person / Time
Site:	LaSalle
Issue date:	06/13/2006
From:	Sands S Plant Licensing Branch III-2
To:	Crane C Exelon Generation Co
Sands, S, NRR/DPLM/LPD III-2, 415-315
Shared Package
ML060400603	List: ML060400599 ML061670221
References
TAC MC3033, TAC MC3034
Download: ML060400599 (21)

Text

June 13, 2006 Mr. Christopher M. Crane, President and Chief Nuclear Officer Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555

SUBJECT:

LASALLE COUNTY STATION, UNITS 1 AND 2, ISSUANCE OF AMENDMENTS RE: OSCILLATION POWER RANGE MONITOR SYSTEM (TAC NOS. MC3033 AND MC3034)

Dear Mr. Crane:

The Nuclear Regulatory Commission has issued the enclosed Amendment No. 177 to Facility Operating License No. NPF-11 and Amendment No. 163 to Facility Operating License No. NPF-18 for the LaSalle County Station, Units 1 and 2, respectively. The amendments are in response to your application dated April 30, 2004, as supplemented by letters dated June 30 and December 17, 2004, July 5 and September 20, 2005, and June 1, 2006.

The amendments revise the technical specifications (TS) associated with the oscillation power range monitor (OPRM) instrumentation. Specifically, the amendments revise TS 3.3.1.3, Oscillation Power Range Monitor (OPRM) Instrumentation; TS 3.4.1, Recirculation Loops Operating; and TS 5.6.5, Core Operating Limits Report (COLR); to insert a new TS section for the OPRM instrumentation, delete the current thermal-hydraulic instability administrative requirements, and add the appropriate references for the OPRM trip setpoints and methodology.

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

Sincerely,

/RA/

Stephen P. Sands, Project Manager Plant Licensing Branch III-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-373 and 50-374

Enclosures:

1. Amendment No. 177 to NPF-11

2. Amendment No. 163 to NPF-18

3. Safety Evaluation cc w/encls: See next page

June 13, 2006 Mr. Christopher M. Crane, President and Chief Nuclear Officer Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555

SUBJECT:

LASALLE COUNTY STATION, UNITS 1 AND 2, ISSUANCE OF AMENDMENTS RE: OSCILLATION POWER RANGE MONITOR SYSTEM (TAC NOS. MC3033 AND MC3034)

Dear Mr. Crane:

The Nuclear Regulatory Commission has issued the enclosed Amendment No. 177 to Facility Operating License No. NPF-11 and Amendment No. 163 to Facility Operating License No. NPF-18 for the LaSalle County Station, Units 1 and 2, respectively. The amendments are in response to your application dated April 30, 2004, as supplemented by letters dated June 30 and December 17, 2004, July 5 and September 20, 2005, and June 1, 2006.

The amendments revise the technical specifications (TS) associated with the oscillation power range monitor (OPRM) instrumentation. Specifically, the amendments revise TS 3.3.1.3, Oscillation Power Range Monitor (OPRM) Instrumentation; TS 3.4.1, Recirculation Loops Operating; and TS 5.6.5, Core Operating Limits Report (COLR); to insert a new TS section for the OPRM instrumentation, delete the current thermal-hydraulic instability administrative requirements, and add the appropriate references for the OPRM trip setpoints and methodology.

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

Sincerely,

/RA/

Stephen P. Sands, Project Manager Plant Licensing Branch III-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-373 and 50-374

Enclosures:

1. Amendment No. 177 to NPF-11

2. Amendment No. 163 to NPF-18

3. Safety Evaluation cc w/encls: See next page DISTRIBUTION:

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LaSalle County Station Units 1 and 2 cc:

Site Vice President - LaSalle County Station Robert Cushing, Chief, Public Utilities Division Exelon Generation Company, LLC Illinois Attorney General's Office 2601 North 21st Road 100 W. Randolph Street Marseilles, IL 61341-9757 Chicago, IL 60601 LaSalle County Station Plant Manager Regional Administrator Exelon Generation Company, LLC U.S. NRC, Region III 2601 North 21st Road 801 Warrenville Road Marseilles, IL 61341-9757 Lisle, IL 60532-4351 Regulatory Assurance Manager - LaSalle Illinois Emergency Management Exelon Generation Company, LLC Agency 2601 North 21st Road Division of Disaster Assistance &

Marseilles, IL 61341-9757 Preparedness 110 East Adams Street U.S. Nuclear Regulatory Commission Springfield, IL 62701-1109 LaSalle Resident Inspectors Office 2605 North 21st Road Document Control Desk - Licensing Marseilles, IL 61341-9756 Exelon Generation Company, LLC 4300 Winfield Road Phillip P. Steptoe, Esquire Warrenville, IL 60555 Sidley and Austin One First National Plaza Senior Vice President of Operations Chicago, IL 60603 Exelon Generation Company, LLC 4300 Winfield Road Assistant Attorney General Warrenville, IL 60555 100 W. Randolph St. Suite 12 Chicago, IL 60601 Vice President - Licensing and Regulatory Affairs Chairman Exelon Generation Company, LLC LaSalle County Board 4300 Winfield Road 707 Etna Road Warrenville, IL 60555 Ottawa, IL 61350 Attorney General 500 S. Second Street Springfield, IL 62701 Chairman Illinois Commerce Commission 527 E. Capitol Avenue, Leland Building Springfield, IL 62706

LaSalle County Station Units 1 and 2 Director - Licensing and Regulatory Affairs Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 Assistant General Counsel Exelon Generation Company, LLC 200 Exelon Way Kennett Square, PA 19348 Manager Licensing - Dresden, Quad Cities and Clinton Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555

EXELON GENERATION COMPANY, LLC DOCKET NO. 50-373 LASALLE COUNTY STATION, UNIT 1 AMENDMENT TO FACILITY OPERATING LICENSE Amendment No. 177 License No. NPF-11

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

A. The application for amendment filed by the Exelon Generation Company, LLC (the licensee), dated April 30, 2004, as supplemented by letters dated June 30 and December 17, 2004, July 5 and September 20, 2005, and June 1, 2006, complies with the standards and requirements of the Atomic Energy Act of 1954, as amended (the Act), and the Commission's 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 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.

2. Accordingly, the license is amended by changes to the Technical Specifications as indicated in the enclosure to this license amendment and paragraph 2.C.(2) of the Facility Operating License No. NPF-11 is hereby amended to read as follows:

(2) Technical Specifications and Environmental Protection Plan The Technical Specifications contained in Appendix A, as revised through Amendment No. 177, and the Environmental Protection Plan contained in Appendix B, are hereby incorporated in the license. The licensee shall operate the facility in accordance with the Technical Specifications and the Environmental Protection Plan.

3. This license amendment is effective as of the date of its issuance and shall be implemented within 150 days of the date of issuance.

FOR THE NUCLEAR REGULATORY COMMISSION

/RA/

Daniel S. Collins, Chief Plant Licensing Branch III-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation

Attachment:

Changes to the Technical Specifications Date of Issuance: June 13, 2006

EXELON GENERATION COMPANY, LLC DOCKET NO. 50-374 LASALLE COUNTY STATION, UNIT 2 AMENDMENT TO FACILITY OPERATING LICENSE Amendment No. 163 License No. NPF-18

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

A. The application for amendment filed by the Exelon Generation Company, LLC (the licensee), dated April 30, 2004, as supplemented by letters dated June 30 and December 17, 2004, July 5 and September 20, 2005, and June 1, 2006, complies with the standards and requirements of the Atomic Energy Act of 1954, as amended (the Act), and the Commission's 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 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.

2. Accordingly, the license is amended by changes to the Technical Specifications as indicated in the enclosure to this license amendment and paragraph 2.C.(2) of the Facility Operating License No. NPF-18 is hereby amended to read as follows:

(2) Technical Specifications and Environmental Protection Plan The Technical Specifications contained in Appendix A, as revised through Amendment No. 163, and the Environmental Protection Plan contained in Appendix B, are hereby incorporated in the license. The licensee shall operate the facility in accordance with the Technical Specifications and the Environmental Protection Plan.

3. This license amendment is effective as of the date of its issuance and shall be implemented within 150 days of the date of issuance.

FOR THE NUCLEAR REGULATORY COMMISSION

/RA/

Daniel S. Collins, Chief Plant Licensing Branch III-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation

Attachment:

Changes to the Technical Specifications Date of Issuance: June 13, 2006

ATTACHMENT TO LICENSE AMENDMENT NOS. 177 AND 163 FACILITY OPERATING LICENSE NOS. NPF-11 AND NPF-18 DOCKET NOS. 50-373 AND 50-374 Replace the following pages of the Facility Operating License and Appendix A, Technical Specifications, with the enclosed pages. The revised pages are identified by an amendment number and contain marginal lines indicating the area of change.

Remove Insert Unit 1 License Page 3 Unit 1 License Page 3 Unit 2 License Page 3 Unit 2 License Page 3 i i

--- 3.3.1.3-1

--- 3.3.1.3-2

--- 3.3.1.3-3 3.4.1-1 3.4.1-1 3.4.1-2 3.4.1-2 3.4.1-3 3.4.1-3 3.4.1-4 ---

3.4.1-5 ---

3.4.1-6 ---

3.4.1-7 ---

5.6-3 5.6-3 5.6-4 5.6-4 5.6-5 5.6-5

(4) Exelon Generation Company, LLC, pursuant to the Act and 10 CFR Parts 30, 40, and 70, to receive, possess, and use in amounts as required any byproduct, source or special nuclear material without restriction to chemical or physical form, for sample analysis or instrument calibration or associated with radioactive apparatus or components; and (5) Exelon Generation Company, LLC, pursuant to the Act and 10 CFR Parts 30, 40, and 70, to possess, but not separate, such byproduct and special nuclear materials as may be produced by the operation of LaSalle County Station, Units 1 and 2.

C. This license shall be deemed to contain and is subject to the conditions specified in the Commissions regulations set forth in 10 CFR Chapter I and is subject to all applicable provisions of the Act and to the rules, regulations, and orders of the Commission now or hereafter in effect; and is subject to the additional conditions specified or incorporated below:

(1) Maximum Power Level The licensee is authorized to operate the facility at reactor core power levels not in excess of full power (3489 megawatts thermal).

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

(3) Conduct of Work Activities During Fuel Load and Initial Startup The licensee shall review by committee all Unit 1 Preoperational Testing and System Demonstration activities performed concurrently with Unit 1 initial fuel loading or with the Unit 1 Startup Test Program to assure that the activity will not affect the safe performance of the Unit 1 fuel loading or the portion of the Unit 1 Startup Program being performed. The review shall address, as a minimum, system interaction, span of control, staffing, security and health physics, with respect to performance of the activity concurrently with the Unit 1 fuel loading or the portion of the Unit 1 Startup Program being performed. The committee for the review shall be composed of at least three members, knowledgeable in the above areas, and who meet the qualifications for professional-technical personnel specified by Amendment No. 177

(5) Pursuant to the Act and 10 CFR Parts 30, 40, and 70 possess, but not separate, such byproduct and special nuclear materials as may be produced by the operation of LaSalle County Station Units 1 and 2.

C. This license shall be deemed to contain and is subject to the conditions specified in the Commissions regulations set forth in 10 CFR Chapter I and is subject to all applicable provisions of the Act and to the rules, regulations, and orders of the Commission now or hereafter in effect; and is subject to the additional conditions specified or incorporated below:

(1) Maximum Power Level The licensee is authorized to operate the facility at reactor core power levels not in excess of full power (3489 megawatts thermal). Items in Attachment 1 shall be completed as specified. Attachment 1 is hereby incorporated into this license.

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

(3) Conduct of Work Activities During Fuel Load and Initial Startup The licensee shall review by committee all Unit 2 Preoperational Testing and System Demonstration activities performed concurrently with Unit 2 initial fuel loading or with the Unit 2 Startup Test Program to assure that the activity will not affect the safe performance of the Unit 2 fuel loading or the portion of the Unit 2 Startup Program being performed. The review shall address, as a minimum, system interaction, span of control, staffing, security and health physics, with respect to performance of the activity concurrently with the Unit 2 fuel loading or the portion of the Unit 2 Startup Program being performed. The committee for the review shall be composed of at least three members, knowledgeable in the above areas, and who meet the qualifications for professional-technical personnel specified by section 4.4 of ANSI N18.7-1971. At least one of these three shall be a senior member of the Assistant Superintendent of Operations staff.

Amendment No. 163

SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 177 TO FACILITY OPERATING LICENSE NO. NPF-11 AND AMENDMENT NO. 163 TO FACILITY OPERATING LICENSE NO. NPF-18 EXELON GENERATION COMPANY, LLC LASALLE COUNTY STATION, UNITS 1 AND 2 DOCKET NOS. 50-373 AND 50-374

1.0 INTRODUCTION

By letter to the Nuclear Regulatory Commission (NRC, Commission) dated April 30, 2004, as supplemented by letters dated June 30 and December 17, 2004, July 5 and September 20, 2005, and June 1, 2006, Exelon Generation Company, LLC (EGC, the licensee), proposed changes to the technical specifications (TSs) for the LaSalle County Station, Units 1 and 2 (LSCS). The supplements dated June 30 and December 17, 2004, July 5 and September 20, 2005, and June 1, 2006, provided additional information that clarified the application, did not expand the scope of the application as initially noticed, and did not change the NRC staffs proposed no significant hazards consideration determination as published in the Federal Register dated June 8, 2004 (69 FR 32073).

EGC proposed changes to the TSs to support the oscillation power range monitor (OPRM) instrumentation as the long-term stability solution implementation for LSCS. The proposed changes include the following:

Adding a new TS Section 3.3.1.3, Oscillation Power Range Monitor (OPRM)

Instrumentation. The minimum number of required operable channels will be four channels and OPRM instrumentation will be required to be operable when reactor power is $ 25-percent rated thermal power (RTP). A note will be added in the Actions section that states, ?Separate Condition entry is allowed for each channel. Limiting Conditions for Operation (LCOs) A, B, and C, which are consistent with the referenced topical report, will be added to TS 3.3.1.3. An administrative change will be made to the Table of Contents to reflect the new TS Section 3.3.1.3.

Revising TS 3.4.1, ?Recirculation Loops Operating, to delete the wording ?within Region III of Figure 3.4.1.1, to delete Actions A, B, C, D1, D2, and E and to rearrange Actions D, F, G, and H in sequence as Actions A, B, C, and D, respectively.

Adding Surveillance Requirements (SRs) 3.3.1.3.1 through 3.3.1.3.6. A note is added, When a channel is placed in an inoperable status solely for performance of required Surveillances, entry into associated Conditions and Required Actions may be delayed for up to 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> provided the OPRM maintains trip capability. Also a statement is

added to SR 3.3.1.3.3 to clarify that the setpoints for the trip function are specified in the Core Operating Limit Report (COLR).

Adding Pages B 3.3.1.3-1 through B 3.3.1.3-11 to explain the basis for the TS Section 3.3.1.3. These pages are not included with the TS change pages, as they are maintained within the licensees bases change control program.

Adding a cycle-specific core operating parameter to TS 5.6.5.a.5, and a corresponding approved methodology to TS 5.6.5.b.25.

In a teleconference on June 6, 2005, between EGC and the NRC, the TS SR to calibrate the local power range monitors (LPRMs) associated with the OPRMs was discussed. This SR was included in the sample TS provided in CENPD-400-P, Revision, 1, Generic Topical Report with the Asea Brown Boveri (ABB) Option III Oscillation Power Range Monitor (OPRM), approved by the NRC in 1995; however, the SR was omitted from the April 30, 2004, submittal since the LPRM calibration was already required as part of the TS 3.3.1.1. As a result of this teleconference, EGC submitted a revised TS page 3.3.1.3-3 to add the LPRM calibration SR to the OPRM TS 3.3.1.3.

By letter dated June 29, 2001, General Electric submitted a Part 21 notification about the concern that stability reload licensing calculations using the generic delta critical power ratio (CPR) over initial minimum critical power ratio (MCPR) versus oscillation magnitude (DIVOM) curve could result in OPRM RPS trip setpoints which may not provide MCPR safety limit protection.

By letter dated September 30, 2003, the Boiling Water Reactor Owners Group (BWROG) submitted the resolution for the Part 21 notification. The resolution will require the licensee to use the plant-specific DIVOM curve, which will be generated or confirmed for each reload fuel cycle consistent with the process described in NEDO-32465-A, BWROG Reactor Core Stability Detect and Suppress Solutions Licensing Basis Methodology and Reload Applications. The plant-specific curves will be reasonably conservative, but not necessarily bounding, for a particular fuel cycle. In conjunction with the 95/95 statistical approach of the licensing methodology, the plant-specific DIVOM curves will result in a high probability that the fuel cladding integrity safety limit will not be violated as a result of anticipated instability events.

In its submittal, the licensee stated that the OPRM system has already been installed at LSCS and is currently being operated in the indicate only mode to evaluate the systems performance. Implementation of the proposed TS revisions will enable the licensee to use the trip function of the OPRM system.

2.0 REGULATORY EVALUATION

In Section 5.2 of Attachment 1 of its submittal, the licensee identified the following regulatory requirements for this amendment request:

General Design Criterion (GDC) 10, Reactor design, of Appendix A to Title 10 of the Code of Federal Regulations (10 CFR), requires that the reactor core and associated coolant, control, and protection systems shall be designed with appropriate margins 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, GDC 12, Suppression of reactor power oscillations, of Appendix A to 10 CFR Part 50, requires that the reactor core and associated coolant, control, and protection systems shall be designed to assure that power oscillations which can result in conditions exceeding specified acceptable fuel design limits are not possible or can be reliably and readily detected and suppressed.

The NRC staff finds that the licensee identified the applicable regulatory requirements in Section 5.0 of its April 30, 2005, submittal. The regulatory requirements that the NRC staff considered in its review of the application are in 10 CFR Part 50. The OPRM system is designed to meet the requirements specified in GDC 10 and GDC 12 of 10 CFR Part 50, Appendix A.

Pursuant to 10 CFR 50.36, Technical Specifications, TSs include items in the following five specific categories related to station operation: (1) safety limits, limiting safety system settings, and limiting control settings; (2) LCOs; (3) SRs; (4) design features; and (5) administrative controls. The rule does not specify the particular requirements to be included in a plants TSs.

As stated in 10 CFR 50.36(c)(2)(i), the Limiting conditions for operation are the lowest functional capability or performance levels of equipment required for safe operation of the facility. When an LCO of a nuclear reactor is not met, the licensee shall shut down the reactor or follow any remedial action permitted by the technical specification...

3.0 BACKGROUND

Under certain conditions, boiling water reactor (BWR) cores may exhibit thermal-hydraulic (T-H) instabilities. These instabilities are characterized by periodic power and flow oscillations. If the oscillations become large enough, the fuel cladding integrity MCPR safety limit and GDC 10 and 12 requirements may be challenged. Based on this possibility, LSCS is currently operating with the interim corrective actions (ICAs) described in the licensees response to NRC Generic Letter (GL) 94-02, ?Long-Term Solutions and Upgrade of Interim Operating Recommendations for Thermal-Hydraulic Instabilities in Boiling Water Reactors. The ICAs include restrictions on plant operation and procedural requirements for operator action in response to instability events.

The requirements of the ICAs and the existing TSs limit the probability of an instability event by restricting the duration of any entry into the regions of the power-flow map most susceptible to instability under the anticipated entry conditions. Actions are also required by the ICAs when conditions consistent with the onset of T-H oscillations are observed. These actions result in the suppression of conditions required for an instability event and thereby prevent any potential challenge to the MCPR safety limit.

Implementation of the proposed TS revisions would allow the RPS trip function of the OPRM system to be enabled consistent with the Asea Brown Boveri Combustion Engineering (ABB-CE) Option III long-term solution for the T-H instability issue. The OPRM reactor protection system (RPS) trip function would provide automatic detection and suppression of conditions that might result in a T-H instability event and would allow elimination of the ICAs.

As a result, the burden on the control room operators would be reduced.

The OPRM, which was installed at LSCS in 1999 to 2000, is currently being operated in the indicate only mode to evaluate the systems performance. The existing ICAs provide an acceptable method of ensuring an adequate margin to the MCPR safety limit until the OPRM RPS trip function is enabled.

The function of the OPRM is to detect core power oscillations and trip (scram) the plant if the magnitude of the oscillations exceeds the setpoint. The OPRM system consists of four OPRM channels and each OPRM channel consists of two OPRM modules either of which can initiate the trip signal for that channel. Each OPRM module receives input from 21 or 22 LPRMs in adjacent areas of the core. Each module also receives input from the other OPRM module in the trip channel, as well as from RPS average power range monitor (APRM) power and flow signals to automatically enable the trip function of the OPRM module. Using a smaller group of LPRMs to monitor instantaneous flux provides better resolution for detecting local oscillations than APRMs alone. The LPRM signals are grouped together so that the resulting OPRM response provides adequate coverage of anticipated oscillation modes. On detecting conditions consistent with the possibility that local oscillations in core power will lead to a T-H instability, the OPRM initiates a reactor scram through the existing RPS trip logic. This capability of the OPRM assures protection of the MCPR safety limit during all anticipated core-wide and regional T-H instability events.

The OPRM system logic configuration conforms to the existing 1-out-of-2-taken-twice logic configuration of the RPS. Each module executes the algorithms on the LPRM signals based on the configuration for that channel and generates alarms and trips. The assigned locations of modules are consistent with the RPS and neutron monitoring system separation requirements.

The system design accounts for isolator accuracy, instrument and system response times, system performance requirements, and addresses redundancy, diversity, separation, and electrical isolation requirements.

The OPRM trip function is enabled when APRM power is $ 28.6 percent of RTP and the recirculating drive flow is less than or equal to the value corresponding to approximately 60 percent of rated core flow. The OPRM provides annunciation to alert the operator when the system is enabled and also provides a pre-trip alarm on detecting an imminent onset of local core power oscillations. The purpose of this alarm is to alert the plant operator to the plant condition in time for compensatory actions to suppress the conditions for an instability event.

Each OPRM module uses three separate algorithms to detect and mitigate core power oscillations. The three algorithms are the period-based detection algorithm (PBDA), the amplitude-based algorithm, and the growth-rate algorithm. The PBDA actuates the RPS trip on detecting oscillations of a certain period and amplitude, and is the only algorithm that is credited in the analysis of the capability of the OPRM system to protect the MCPR safety limit. The remaining two algorithms provide defense-in-depth and additional protection for T-H instability events.

3.1 TECHNICAL EVALUATION

In its submittal, the licensee stated that the implementation of the proposed changes will reduce the reliance on the operator because the OPRM system automatically protects against MCPR safety limit violations during conditions that could lead to T-H instability and that the proposed changes will not cause any degradation in the existing APRM, LPRM, and RPS systems or adversely impact the design basis and operation of any interfacing equipment (i.e., the APRM,

RPS, recirculation flow unit, and LPRM systems). The NRC staff has previously reviewed the design and effectiveness of the OPRM system and has approved the system for meeting the regulatory requirements to detect and suppress conditions that could lead to a T-H instability.

The NRC staffs approval of the OPRM system is documented in safety evaluation reports (SERs) on the following topical reports:

1. NEDO-32645-A, BWROG Reactor Core Stability Detect and Suppress Solutions Licensing Basis Methodology and Reload Applications, August 1996,

2. NEDO-31960-A, BWROG Long-Term Stability Solutions Licensing Methodology, November 1995,

3. NEDO-31960-A, Supplement 1, BWROG Long Term Stability Solutions Licensing Methodology, November 1995, and

4. CENPD-400-P-A, Revision 1, Generic Topical Report for the ABB Option III Oscillation Power Range Monitor (OPRM), May 1995.

3.2 Specification 3.3.1.3 - Oscillation Power Range Monitor (OPRM) Instrumentation The licensee proposed to add a new TS for the OPRM instrumentation, which includes the LCO, Applicability, Actions and SRs (SR 3.3.1.3.1 through SR 3.3.1.3.6) necessary to define Operability of the OPRM channels, and the actions the plant operators must take when the instruments become inoperable.

The NRC staffs SER approving CENPD-400-P-A requires licensees to address the following six issues in their plant-specific submittals for implementing the ABB-CE Option III OPRM system as a permanent long-term solution for the T-H stability issue and to identify and justify any deviations from CENPD-400-P-A and the associated SER:

(I) Confirm the applicability of CENPD-400-P-A, including clarifications and reconciled differences between the specific plant design and the topical report design descriptions.

In its submittal the licensee stated that the LSCS installation and implementation of the OPRM are consistent with CENPD-400-P-A and the associated SER and there are no deviations.

(II) Confirm the applicability of the BWROG topical reports that address the OPRM and associated instability function, setpoints, and margins.

The BWROG topical reports that address the OPRM and associated instability functions, setpoints, and margins are NEDO-31960-A and its supplement NEDO-32465-A. In its submittal, the licensee confirmed the applicability of NEDO-31960-A and its supplement NEDO-32465-A for implementation of the Option III OPRM system at LSCS. The conditions and limitations in the NRC staffs SEs on these topical reports were addressed as follows:

(a) All three algorithms described in NEDO-31960-A and Supplement 1 should be used in Option III or III-A. These three algorithms are the high LPRM oscillation amplitude, the high-low detection algorithm, and the period-based algorithm.

The licensee confirmed that all three algorithms are included in the Option III design. Only the PBDA is used to demonstrate protection of the MCPR safety limit for anticipated reactor instabilities. The other two algorithms are included as defense-in-depth features. Only the PBDA is required for TS operability of the OPRM instrumentation. This is acceptable because an approved methodology is used and all three algorithms are included in LSCS Option III design.

(b) The validity of the scram setpoints selected should be demonstrated by analysis. These analyses may be performed for a generic representative plant when applicable, but should include an uncertainty treatment that accounts for the number of failed sensors permitted by the TSs of the plants applicant.

The licensee stated that the methodology as described in NEDO-32465-A was followed for the PBDA including analysis of sensor failure in the OPRM system, cycle-specific analysis for the applicability of the scram setpoints, and OPRM system operability. This is acceptable because the procedures specified in the approved methodology are used.

(c) Implementation of Option III will require that the selected bypass region outside of which the detect and suppress action is deactivated be defined in the TSs.

The licensee confirmed that this region is included in SR 3.3.1.3.5. The exclusion region methodology (safety analyses contained in NEDO-31960-A) would define a curved region on the power to flow operating map cutting across the corner of the map near the intersection of the natural circulation line and the highest flow control line.

The NRC staff has reviewed the licensees response and found it acceptable because the proposed exclusion region in conjunction with SR 3.3.1.3.5 is consistent with the boundaries discussed in NEDO-32465-A, Section 2.2.

(d) If the algorithms detect oscillations, an automatic protective action should be initiated.

This action may be a full scram or a selected rod insert (SRI).

The licensee confirmed that the automatic protective action of the OPRMs at LaSalle will be a full reactor scram, rather than an SRI.

The NRC staff has reviewed the licensees response and found it acceptable because the action is in compliance with GDCs 10 and 12.

(e) The LPRM groupings defined in NEDO-31960-A to provide input to Option III algorithms are acceptable for the intended oscillation detection function. These LPRM groupings are the OPRM for Option III.

The licensee explained that the four LPRMs per OPRM Cell - 4BL (Blockstanz-Lehmann Design) configuration is used at LSCS.

The NRC staff reviewed the licensees description and found it acceptable because this configuration is one of the Example LPRM assignments given in the approved TRs NEDO-32465P-A and NEDO-31960-A.

(III) Provide a plant-specific technical specification (TS) for the OPRM functions consistent with CENPD-400-P, Appendix A.

In its submittal, the licensee stated that the proposed TSs are consistent with CENPD-400-P, Appendix A, except for the following deviations:

a. The TS change in the topical report includes a SR (SR 3.3.1.3.2) to calibrate the LPRMs every 1000 megawatt days per metric ton (MWD/MTU). This value is bracketed in the topical report, which indicates that plant-specific information should be substituted. LSCS SR 3.3.1.1.8 currently requires this calibration at a frequency of 1000 effective full power hours (EFPHs) which is based on operating experience with LPRM sensitivity changes. Since 1 EFPH equals approximately 0.9 MWD/MTU at LSCS, the value specified is more conservative than in the topical report. Therefore, this change is acceptable to the NRC staff.

b. SR 3.3.1.3.3 states that the trip setpoint for this function is specified in the COLR (for consistency with the statement added to TS Section 5.6.5.a). The NRC staff finds this acceptable as this setpoint must be revised every refueling outage based on the reload analysis, which the NRC staff reviews for acceptability.

c. SR 3.3.1.3.5 verifies that the OPRM system is not bypassed with reactor power

$ 28.6 percent RTP and recirculation drive flow < 60 percent of rated recirculation drive flow. The 60-percent value is consistent with the value in the topical report. However, the 28.6-percent value is the plant-specific value and is based on the 5-percent power uprate. To preserve the same level of protection against the occurrence of a TH instability, the instability exclusion region boundaries were unchanged with respect to absolute power level. Since the reactor core flow did not change with the power uprate, its value did not change. However, the 30-percent RTP value was reduced by the ratio of 100 percent/105 percent, reducing the power portion of the enabled region to 28.6-percent RTP. Based on this, the NRC staff finds the proposed change acceptable.

(IV) Confirm that the plant-specific environmental (temperature, humidity, radiation, electromagnetic and seismic) conditions are enveloped by the OPRM equipment environmental qualification values.

In its submittal, the licensee stated that the OPRM is designed to meet the temperature, radiation, and seismic environmental conditions at LSCS. At LSCS, OPRM equipment is installed in the main control room and is qualified to perform its intended design functions continuously in the control room environment except at the lower end of the control room humidity range. The OPRM equipment is qualified to 30-percent relative humidity whereas the LSCS humidity could go as low as 20-percent on a temporary basis. The licensee has analyzed the effect of low humidity on OPRM equipment and has determined that it will continue to operate properly if relative humidity is temporarily below 30-percent. The OPRM system is designed to provide a high degree of immunity from electromagnetic interference/radio frequency interference (EMI/RFI), and to minimize EMI/RFI that may interfere with the devices connected to the system, the devices that share a common power source, and the devices located in the same enclosure. The licensee further stated that equipment for the

proposed OPRM trip has been qualified for EMI and RFI susceptibility. However, in response to the NRC staffs request to identify the EMI/RFI level to which these equipments are qualified, the licensee in its December 17, 2004, letter committed to confirm that the site-specific EMI/RFI level at the installed OPRM location is enveloped by the test level prior to arming the OPRM.

Based on this commitment, the NRC staff finds that the licensee has satisfactorily addressed this issue.

(V) Confirm that administrative controls are provided for manually bypassing OPRM channels or protective functions and for controlling access to the OPRM functions.

In its submittal, the licensee stated that the OPRM implementation at LSCS is consistent with the NRC staffs SER. Plant administrative control procedures will be provided for placing individual OPRM modules in manual bypass. When the OPRM modules are not in manual bypass, the OPRM protective function is automatically bypassed or automatically activated when the reactor power and recirculation flow in the appropriate regions of the reactor power/flow map require automatic bypass or activation. The main control room sequence of event recorder or indicating lights are activated if the OPRM has been manually bypassed or deliberately rendered inoperative.

(VI) Confirm that any changes to the plant operators main control room panel have received human factors reviews per plant-specific procedures.

In its submittal, the licensee stated that for OPRM implementation, the OPRM instrumentation and associated components, controls, and annunciators were evaluated for acceptability and conformance to human engineering design principles and were found acceptable. There are procedural requirements for placing an OPRM module in bypass and for verifying restoration.

Keylock access is necessary to manually bypass an OPRM module and changes to OPRM software require both keylock access and a password.

The licensees above-described responses to the six issues of the NRC staff SER are acceptable. On this basis, the NRC staff believes that LSCS will continue to meet the requirements of GDC 10 and 12, and therefore finds the proposed TS changes acceptable.

The LSCS is currently operating under the interim corrective actions described in the licensees response to NRC GL 94-02. The interim corrective actions include restrictions on plant operation and procedural requirements for operator actions in response to T-H instability events. Since the OPRM system trip function will provide reliable detection and suppression of conditions leading to T-H instability events, operation of the plant in regions of the power/flow map potentially susceptible to T-H instability will be acceptable. Therefore, the current TS requirements which limit plant operation in these regions of power/flow map are unnecessary and can be deleted. This is acceptable to the NRC staff.

In its submittal, the licensee stated that the capability of the OPRM to maintain the margin of safety associated with the MCPR safety limit for instability events has been demonstrated by a plant-specific analysis based on the NRC staff-approved methodology described in NEDO-32645-A and that this capability will be verified as part of the cycle-specific core reload analysis for future operating cycles. This is acceptable to the NRC staff.

The licensees proposed TS Bases are consistent with the referenced topical reports and with the removal of the ICAs and, therefore, are acceptable to the NRC staff.

3.3 Specification 3.4.1 - Recirculation Loop Operating The licensee proposed to delete Figure 3.4.1-1, Power versus Flow, and associated references to the figure from the LCO 3.4.1, Actions A, B, C, and E, and SR 3.4.1.2, and to revise/renumber Actions D, F, G, and H.

The NRC staff has reviewed the proposed changes and found them acceptable because the manual operator actions specified in TS LCO 3.4.1 (and its associated Conditions A, B, C, and E; Actions A.1 through A.3, B.1, C.1, and E.1; and SRs 3.4.1.2) are no longer in use due to the automatic functions provided by the OPRMs.

3.4 Specification 5.6.5 - Core Operating Limits Report (COLR)

The licensee proposed to add: (1) a new TS 5.6.5.a.5, ?The OPRM setpoints for the trip function for SR 3.3.1.3.3; and (2) a new TS 5.6.5.b.25 NEDO-32465-P-A, BWR Owners Group Reactor Stability Detect and Suppress Solutions Licensing Basis Methodology for Reload Applications, August 1996.

The NRC staff has reviewed the proposed changes and found them acceptable because NEDO-32465-P-A is an approved licensing topical report to support the new proposed TS 3.3.1.3 and SRs (SR 3.3.1.3.1 through SR 3.3.1.3.6) for determining the setpoint values of the applicable operating limits for OPRMs in the COLR. The licensee has provided cycle-specific parameters for the OPRM Amplitude Trip Setpoints and the associated OPRM Confirmation Count Trip Setpoint. The approved methodologies listed in TS 5.6.5.b should also be updated timely to reflect their appropriate use for application of the cycle-specific core operating parameters described in TS 5.6.5.a.

Based on the above evaluation, the NRC staff concludes that the OPRM system, when implemented, will provide timely automatic protection during T-H instability events and will reduce operator burden, and therefore will be beneficial. The licensees responses to the six conditions required by the NRC staffs SER are acceptable. The licensee should confirm that any corrective actions resulting from the licensees evaluation of the EMI/RFI qualification have been completed prior to activating the OPRM trip function. The proposed system will not degrade existing APRM, LPRM, and RPS systems. The proposed TS revisions to use the trip function of the OPRM are acceptable.

Additionally, based on the review of the licensees submittal, the NRC staff concludes that the above described TS changes, and associated Bases, involving the implementation of the BWROG long-term stability solution Option III, using ABB-CE OPRM instrumentation for LSCS are acceptable because the proposed TS changes are in accordance with the approved methodology.

As discussed above, the NRC staff has evaluated the proposed changes to TSs and the SRs related to the setpoint values of the operating limits for the OPRM. Based on the above evaluation, the NRC staff concludes that it is safe to operate the plant using the proposed

changes to the TSs and the SRs and, therefore, the proposed changes meet the requirements of 10 CFR 50.36. Based on this conclusion, the NRC staff further concludes that the proposed amendment is acceptable.

4.0 STATE CONSULTATION

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

5.0 ENVIRONMENTAL CONSIDERATION

This amendment changes 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 surveillance requirements. The staff has determined that the amendment involves no significant increase in the amounts, and no significant change in the types, of any effluent 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 (69 FR 32073; June 8, 2004). 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 amendment.

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) 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: H. Garg T. Huang Date: June 13, 2006