ML031060008

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Request for Notice of Enforcement Discretion Concerning Direct Current Electrical Power Distribution Systems
ML031060008
Person / Time
Site: LaSalle Constellation icon.png
Issue date: 04/11/2003
From: Barnes G
Exelon Generation Co, Exelon Nuclear
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
Download: ML031060008 (14)


Text

ExekrnSM Exelon Generation Company, LLC www exeloncorp corn Nuclear LaSalle County Station 2601 North 21' Road Marseilles, IL 61341-9757 April 11, 2003 United States Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555 LaSalle County Station, Unit 1 Facility Operating License No. NPF-1 1 NRC Docket No. 50-373

Subject:

Request for Notice of Enforcement Discretion Concerning Direct Current (DC) Electrical Power Distribution Systems The purpose of this letter is to docket a request by Exelon Generation Company (EGC), LLC, for Enforcement Discretion from compliance with LaSalle County Station (LSCS) Unit 1 Technical Specifications (TS) 3.8.4, "DC Sources - Operating" and 3.8.7, "Distribution Systems - Operating."

The Unit 1, Division 2, battery charger began exhibiting a fluctuating amperage output on April 7, 2003. The battery charger was subsequently rendered inoperable for repair activities at 1742 on April 9, 2003. Use of a temporary non-class 1E battery charger during maintenance activities will also render the associated Unit 1, Division 2 125 VDC electrical power distribution subsystem inoperable. Repair and testing of the battery charger will require up to 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> beyond the 2-hour Completion Time for TS 3.8.4 Condition A and the 2-hour Completion Time for TS 3.8.7 Condition B before commencing a unit shutdown.

LSCS TS 3.8.4 Condition A allows the Division 1 or 2 125 VDC electrical power subsystem to be inoperable for two hours. If operability cannot be restored, then Required Action E.1 requires the unit to be in Mode 3 in 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and Required Action E.2 requires the unit to be in Mode 4 in 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />.

LSCS TS 3.8.7 Condition B allows Division 1 or 2 125 VDC electrical power subsystem to be inoperable for two hours. If operability cannot be restored, then Required Action D.1 requires the unit to be in Mode 3 in 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and Required Action D.2 requires the unit to be in Mode 4 in 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />.

April 11, 2003 U.S. Nuclear Regulatory Commission Page 2 To remedy the battery charger's fluctuating ampere output, we believe it is prudent to repair the battery charger and restore operability to the DC electrical power distribution system without having to place the unit in a shutdown transient. Specifically, we request a one-time relief from TS 3.8 4, Required Actions A.1 and TS 3.8.7 Required Action B.1 to extend the Completion Time an additional 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> to restore the inoperable division to OPERABLE status. LSCS Unit 1 entered TS 3.8.4 Condition A and TS 3.8.7, Condition B at 1742 on April 9, 2003.

The attached enclosure provides the following information necessary for approval of the requested enforcement discretion:

- TS or other license conditions that will be violated;

- Circumstances surrounding the situation, including apparent root causes, the need for prompt action and identification of any relevant historical events;

- Safety basis for the request, including an evaluation of the safety significance and potential consequences of the proposed course of action; -

- Justification for the duration of the request;

- Basis for the determination that the noncompliance will not be of potential detriment to the public health and safety and that no significant hazard consideration is involved;

- Basis for concluding that the noncompliance will not involve adverse consequences to the environment;

- Proposed compensatory actions;

- Acknowledgement of Plant Operations Review Committee approval;

- Basis for concluding that the NOED criteria are satisfied and how they are satisfied;

- Marked up Technical Specification pages (Not Applicable);

- Severe weather or other external condition detailed information (Not Applicable); and

- Other supporting information.

April 11,2003 U.S. Nuclear Regulatory Commission Page 3 This request was verbally transmitted to members of the NRC staff on April 9, 2003, at 1200 hours0.0139 days <br />0.333 hours <br />0.00198 weeks <br />4.566e-4 months <br />, with subsequent approval being verbally granted at 1358 hours0.0157 days <br />0.377 hours <br />0.00225 weeks <br />5.16719e-4 months <br />.

Should you have any questions concerning this letter, please contact Mr. Glen T. Kaegi, Regulatory Assurance Manager, at (815) 415-2800.

Respectfully, George P. Barnes Site Vice President LaSalle County Station

Enclosure:

Request for Enforcement Discretion for Concerning Direct Current (DC) Electrical Power Distribution System cc: Regional Administrator - NRC Region IlIl NRC Senior Resident Inspector - LaSalle County Station

ENCLOSURE LASALLE COUNTY STATION UNIT I REQUEST FOR ENFORCEMENT DISCRETION FOR TECHNICAL SPECIFICATION DC SOURCES - OPERATING FACILITY OPERATING LICENSE NPF-11

1.0 TECHNICAL SPECIFICATION OR LICENSE CONDITIONS THAT WILL BE VIOLATED; Exelon Generation Company (EGC), LLC, LaSalle County Station (LSCS) Unit 1 is requesting enforcement discretion from the Completion Time requirements of Technical Specification (TS) 3.8.4 Condition A and TS 3.8.7 Condition B. If operability of the Unit 1, Division 2 125 volt direct current (VDC) battery charger can not be restored within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> as directed by TS 3.8.4, Required Action A.1 and TS 3.8.7, Required Action B.1, then TS 3.8.4, Required Action E.1 and TS 3.8.7, Required Action D.1 directs that Unit 1 be in Mode 3 in 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and TS 3.8.4, Required Action E.2 and TS 3.8.7, Required Action D.2 directs that Unit 1 be in Mode 4 in 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />.

The OPERABILITY of direct current (DC) subsystems is consistent with the initial assumptions of the accident analyses and is based upon meeting the design basis of the unit. This includes maintaining DC sources OPERABLE during accident conditions including an assumed loss of all offsite alternating current (AC) power or of all onsite AC power; and a worst case single failure. The minimum specified independent and redundant DC power sources and distribution systems satisfy the requirements of General Design Criteria 17, "Electrical power systems," of Appendix A to 10 CFR Part 50. The DC electrical power system provides the AC emergency power system with control power. It also provides both motive and control power to selected safety related equipment. As required by 10 CFR 50, Appendix A, GDC 17, the DC electrical power system is designed to have sufficient independence, redundancy, and testability to perform its safety functions, assuming a single failure.

The 125 VDC electrical power system for each unit consists of independent and redundant safety-related Class 1E DC electrical power subsystems (i.e., Division 1, 2, 3, and Division 2 of the opposite unit). Each subsystem consists of one 125 VDC battery, the associated battery charger for each battery, and all the associated control equipment and interconnecting cabling.

Each system is required to be operable to ensure the availability of the required power to shut down the reactor and maintain it in a safe condition after a design basis accident (DBA). Loss of any division DC electrical power system does not prevent the required safety function from being performed.

An operable DC electrical power subsystem specifies the required battery and respective charger to be operating and connected to the associated DC bus. Each Division of DC electrical power system battery charger has ample power output capacity for the steady state operation of connected loads required during normal operation, while at the same time maintaining its battery bank fully charged.

TS 3.8.4, Condition A and TS 3.8.7 Condition B allows Division 1 or 2 125 VDC electrical power subsystem to be inoperable for 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />, which results in a loss of ability to completely respond to an event, and a potential loss of ability for the DC division to remain energized during normal operation. The 2-hour limit is consistent with the time allowed for an inoperable DC division.

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2.0 CIRCUMSTANCES SURROUNDING THE SITUATION, INCLUDING APPARENT ROOT CAUSES, THE NEED FOR PROMPT ACTION AND IDENTIFICATION OF ANY RELEVANT HISTORICAL EVENTS; At the time of this request, LSCS Unit 1 is operating in Mode 1, (Power Operations), at approximately 100% power. During operation, it was identified that the Unit 1, Division 2 125-volt battery charger ampere output was fluctuating To repair the battery charger, it was necessary to render the battery charger inoperable and install a temporary, non-class 1E battery charger on the distribution system. This resulted in the Unit 1, Division 2 125 volt DC subsystem being rendered inoperable at 1742 on April 9, 2003. The repair, and post maintenance testing of the battery charger will require up to 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> beyond the 2-hour TS Completion Time before commencing a unit shutdown.

Immediate plans were developed to troubleshoot and/or repair the affected battery charger and restore it to OPERABLE status. Troubleshooting has verified that the there are no internal shorts or grounds. Voltage checks have been performed on the voltage sensing card, amplifying modulation card, and firing module and indications of oscillations are present at the input of the firing module. This indicates a stability problem in the voltage sensing card or amplifying modulation card. A plan was developed to replace these cards and perform associated post-maintenance testing.

Replacing these cards will require rendering the Unit 1 Division 2 battery charger inoperable and installing a temporary non-class 1E battery charger to the DC distribution subsystem. Should it be determined that the problem is also associated with the capacitor filters, silicon controlled rectifiers, or power portion of the firing module, it may require a four-hour battery charger capacity test for post-maintenance testing.

At approximately 1023 on April 8, 2003, two Reactor Core Isolation Cooling (RCIC) valve indications (1E51 -F004 (F-004), RCIC Barometric Condenser Condensing Pump Discharge to the Reactor Building Equipment Drain Tank and 1E51 -F025 (F025), RCIC Steam Supply Drain Pot Outlet Upstream Stop) were lost. This resulted in a loss of control power, which rendered Unit 1 RCIC inoperable. Maintenance and Operations performed an inspection of Bus 12Y, breaker number 3, which provides the control power for the F-004 and F-025 (this is a double pole double throw breaker). It was observed that the breaker was still in the ON position. Voltage readings were taken on the load side of the breaker that resulted in a negative 66 VDC on both leads, indicating that the positive terminal on the breaker was impacted. The breaker was then opened and voltage measurements verified that the breaker properly opened and the voltage and current oscillations on the Unit 1; Division 2 battery charger continued at the same amplitude and frequency. During removal of breaker number 3 it was noted that on the positive side of the breaker where it bolts to the bus, the screw was backed off approximately 2 turns. A new tested breaker was installed in the number 3 position of Bus 112Y, post-maintenance testing was satisfactorily performed and RCIC was declared operable at 1700 on April 8,12003. Bench testing of the removed breaker consisted of cycling the breaker several times and taking resistance readings across the contacts of both poles. These results were satisfactory, indicating the breaker was operating properly. As further validation that the breaker was operating properly, it was then put on a portable testing device for a load test and load trip check. Once again the results were satisfactory, indicating that the breaker was functioning properly. Based on the above information, it is our conclusion that the loose connection on the positive lead 3

of the breaker caused the loss of positive DC voltage coming from Bus 112Y. Therefore, the battery charger problems on the Unit 1, Division 2 are unrelated to the failure of this breaker.

There were no precursors to this degradation of the battery charger. An extent of condition review was conducted for the other LSCS class 1E battery chargers to determine if they exhibited the same symptoms. None of the other LSCS class 1E battery chargers exhibit the fluctuating current or voltage symptoms. The plant currently has a request to adopt Technical Specification Task Force (TSTF) 360, "DC Electrical Rewrite," Revision 1, Battery Allowed Outage Time (AOT) extension, planned for submittal in the fall of 2003. This change will allow the battery charger AOT to be increased to 7 days when the associated battery is maintained at its float voltage.

Additionally, a redundant class IE 125 VDC battery charger is scheduled to be installed on Unit 1 during the January 2004 refuel outage.

Enforcement discretion is requested to allow completion of the repair and post maintenance testing of the Unit 1, Division 2 battery charger without having to put the unit in a shutdown transient. Specifically, enforcement discretion is requested for TS 3.8.4 and 3.8.7, for a one-time extension of the Completion Time to restore the inoperable division to OPERABLE status by an additional 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.

3.0 SAFETY BASIS FOR THE REQUEST, INCLUDING AN EVALUATION OF THE SAFETY SIGNIFICANCE AND POTENTIAL CONSEQUENCES OF THE PROPOSED COURSE OF ACTION; This Regional Notice of Enforcement Discretion (NOED) from TS is requested in order to avoid placing LSCS Unit 1 in a shutdown condition, and cycling the unit through a thermal transient. The integrity of the reactor vessel and other components of the primary system of a nuclear plant can be adversely affected by the number of thermal transients that they are subjected to during their lifetime. As each additional thermal transient can affect this integrity, it is prudent to avoid such transients provided the health and safety of the public is preserved. Enforcement discretion is requested from TS 3.8.4, Required Actions A.1 and TS 3.8.7, Required Actions B.1 for LSCS Unit 1.

LSCS Unit 1 is currently operating in Mode 1. A one-time 12-hour extension to the Completion Time is proposed for restoration of the inoperable Division 2 DC electrical power subsystem.

LSCS Unit 1 is provided with three independent Class 1E 125 VDC electrical power subsystems, Divisions 1, 2, and 3. Unit 1, Division 1 battery supplies Engineered Safeguards Feature (ESF) Division 1 load requirements and Unit 1, Division 2 Battery supplies ESF Division 2 load requirements. The Division 3 safety related DC power provides power for the High Pressure Core Spray diesel generator field flashing control logic and switching function of 4.16 kV Division 3 breakers. They are electrically isolated and physically separated so that any failure involving one train cannot jeopardize the function of the other train.

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The DC electrical power distribution system provides the AC emergency power distribution system with control power. It also provides both motive and control power to selected safety related equipment.

The Class 1E 125 VDC battery systems supply power to Class 1E loads without interruption during normal operations or DBA conditions. Each Class 1E 125 VDC system consists of one battery, one main distribution bus, one static battery charger, and local distribution panels. Redundancy and independence of components precludes the loss of both systems as a result of a single failure. There is no sharing between redundant Class 1E trains of equipment such as batteries, battery chargers, or distribution panels.

Each Class 1E 125 VDC system has the capacity to continuously supply the normally connected normal running loads while maintaining its respective battery in a fully charged condition. Each battery was sized based upon supplying the design duty cycle in the event of loss of offsite AC power concurrent with a LOCA and a single failure of a diesel generator. There are fifty-eight (58) cells for each 125 VDC battery. Fifty-seven (57) cells are required for operability of the battery.

The primary sources of Class I E DC power systems are the battery chargers. Each battery charger is capable of floating the battery on the bus or recharging a completely discharged battery while supplying the largest combined demands of the various steady state loads under all plant operating conditions. Each battery charger is fed from a 480-volt alternating current (VAC) ESF switchgear bus of the same division. A temporary non-class 1E battery charger powered from a non-safety related source will maintain the Unit 1, Division 2 battery fully charged during non-accident conditions. The temporary non-class 1E battery charger has the same ratings as the installed class 1E battery charger (i.e., same input loading and 200 ampere current capability) with a 100 amphere output breaker to the DC bus. A contingency has been prepared to power the temporary non-class 1E battery charger from a safety related source should it be required. With a fully charged battery, the plant can withstand the DBA without a qualified charger and assuming a single failure.

Extending the Completion Times for LSCS Unit 1 for 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> involves operating for the requested additional time frame, without one of three subsystems of operable Class 1E 125 VDC power. The consequences of any accident on LSCS Unit 1 during the proposed 12-hour extension to the Completion Time remain unchanged from the consequences associated with complying TS 3.8.4 Required Action A.1 and TS 3.8.7 Required Action B.1. The redundancy and independence of the DC electrical power subsystems ensure the required safety functions are performed as designed consistent with single failure criteria. I Currently, the redundant Class 1E 125 VDC Division 1 and opposite Unit 2, Division 2 power supply is OPERABLE and will be protected during this repair evolution. The Unit 1, Division 1 125 VDC system surveillances were last completed satisfactorily on January 29, 2002. The Unit 2, Division 2 125 VDC system surveillances were last completed satisfactorily on January 29, 2003. The Unit 1, Division 1 Technical Specification Quarterly Surveillance was last completed satisfactorily on April 3, 2003.

The Unit 1, Division 2 Technical Specification Quarterly Surveillance was last completed 5

satisfactorily on January 23, 2003. The Unit 1, Division 3 Technical Specification Quarterly Surveillance was last completed satisfactorily on January 16, 2003. The Unit 2, Division 2 Technical Specification Quarterly Surveillance was last completed satisfactorily on January 9, 2003.

The RCIC system is designed to operate either automatically or manually following reactor pressure vessel (RPV) isolation accompanied by a loss of coolant flow from the feedwater system to provide adequate core cooling and control of RPV water level.

Under these conditions, the High Pressure Core Spray (HPCS) and RCIC systems perform similar functions. The RCIC System is not an ESF System and no credit is taken in the safety analyses for RCIC System operation.

The risk associated with continued operation of LSCS Unit 1 for 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> beyond applicable LCO time with a class 1E battery charger unavailable was evaluated. The LSCS Probabilistic Risk Assessment (PRA) models the 125 and 250 VDC batteries and their associated chargers for significant plant upset conditions. The battery chargers are required over the 24-hour mission time assumed by the PRA model. Without a battery charger, the battery is assumed to fail prior to the 24-hour mission time. A temporary non-class 1E battery charger fed off a non-safety related power source will be in operation during the time the normal class 1E battery charger is unavailable. Due to the magnitude of the loads and the non-safety related power supply, it was conservatively assumed that the temporary non-class 1E battery charger is inadequate for Loss of Offsite Power (LOOP) and for Loss of Coolant Accidents (LOCAs). During these scenarios, it was assumed that the Division 2 battery fails prior to the 24-hour mission time.

A review of the dominant risk cutsets shows the increase in risk is largely due to LOOP scenarios. This risk was quantified and found to be small when appropriate credit, as described above, was provided for the temporary non-class 1E battery charger, prior to consideration of other compensatory measures. Based on the results of the risk evaluation, there is no significant increase in radiological risk as a result of the unavailability of the Unit 1, Division 2 battery charger. The impact on quantifiable risk associated with continued operation is not risk significant in comparison with the acceptance criteria stated in the Electrical Power Research Institute (EPRI) "PSA Applications Guide." In addition, the compensatory actions described in Section 7.0 of this NOED request provide a reduction in risk. Furthermore, continued operation avoids the risk incumbent in a forced shutdown compared to continued operation in a relatively steady-state mode. Therefore, there is no net increase in radiological risk as a result of the unavailability of the Unit 1, Division 2 battery charger.

4.0 JUSTIFICATION FOR THE DURATION OF THE NONCOMPLIANCE; The 12-hour duration is based on the time required to execute necessary repairs and complete post-maintenance testing. LSCS has determined that there is no net increase in the safety consequence of delaying the shutdown time for an inoperable DC electrical power subsystem by an additional 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. The increased risk of extending the Completion Time for the battery prior to a plant shutdown is mitigated by the compensatory actions that are in place to mitigate the consequences of any potential 6

accident or transient. In addition, there is the inherent risk introduced by imposing the operational transient of unnecessarily shutting down the unit. The inherent risk of a unit shutdown is judged to offset the minimal risk associated with the approval of this request. Therefore, the short duration of the requested Enforcement Discretion is justified.

5.0 BASIS FOR DETERMINING THAT THE NONCOMPLIANCE WILL NOT BE OF POTENTIAL DETRIMENT TO THE PUBLIC HEALTH AND SAFETY AND THAT NO SIGNIFICANT HAZARDS CONSIDERATION IS INVOLVED; EGC has evaluated the proposed request and determined that it involves no significant hazards considerations. According to 10 CFR 50.92(c), the proposed request involves no significant hazards considerations if operation of the facility in accordance with the Enforcement Discretion would not:

1. Involve a significant increase in the probability or consequences of an accident previously evaluated; or
2. Create the possibility of a new or different kind of accident from any accident previously evaluated, or
3. Involve a significant reduction in a margin of safety.

A. The proposed Enforcement Discretion does not involve a significant increase in the probability of occurrence or consequences of an accident previously evaluated.

The proposed action allows continued operation, for up to an additional 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, with an inoperable 125 VDC battery charger and electrical power distribution subsystem. An inoperable battery charger and electrical power distribution subsystem are not considered as an initiator of any analyzed event. Therefore, this change will not significantly increase the probability of occurrence of any event previously analyzed in the current LSCS Updated Final Safety Analysis Report (UFSAR).

The consequences of a previously analyzed event are dependent on the initial conditions assumed in the analysis, and the availability and successful functioning of equipment assumed to operate in response to the analyzed event, and the setpoints at which these actions are initiated. The failure of one train (i.e., Single Failure Criteria) of Class 1E 125 VDC power is a condition assumed in the analyses. The ability to respond to a LOOP/LOCA in conjunction with a limiting single failure is maintained. Continued operation with an inoperable battery charger and electrical power distribution subsystem for an additional 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> will not significantly increase the consequences of an accident previously evaluated in the UFSAR since the Division 2 battery in a fully charged state and the redundant train of Class 1E 125 VDC power has the full capability of supplying power to all of the division 2 ESF loads.

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B. The Proposed Enforcement Discretion does not create the possibility of a new or different kind of accident from any accident previously evaluated.

The proposed action does involve the installation of a non-class 1E battery charger. A review of this installation has been performed and has determined that it does not introduce the possibility of a new or different failure mode. There is no change being made to the parameters within which the unit is operated.

There are no setpoints at which protective or mitigative actions are initiated that are affected by this proposed action. This proposed action will not alter the manner in which equipment operation is initiated, nor will the function demands on credited equipment be changed. No alteration in the procedures, which ensure the unit remains within analyzed limits, is proposed, and no change is being made to procedures relied upon to respond to an off-normal event. As such, no new failure modes are being introduced. The proposed action does not alter assumptions made in the safety analysis. Therefore, the proposed action does not create the possibility of a new or different kind of accident from any accident previously evaluated.

C. The proposed Enforcement Discretion does not involve a significant reduction in a margin of safety.

Margins of safety are established in the design of components, the configuration of components to meet certain performance parameters, and in the establishment of setpoints to initiate alarms or actions. This proposed action will allow the unit to remain at power for an additional 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> with an inoperable battery charger. This condition will not significantly reduce the margin of safety previously evaluated in the UFSAR since the redundant subsystems of Class 1E 125 VDC power have the required capability. Therefore, there is no significant reduction in the margin of safety.

Therefore, based on the above evaluation, EGC has concluded that this request for enforcement discretion does not involve significant hazards consideration.

6.0 BASIS FOR CONCLUDING THAT THE REQUEST DOES NOT INVOLVE ADVERSE CONSEQUENCES TO THE ENVIRONMENT; EGC has evaluated this requested enforcement discretion against the criteria for identification of licensing and regulatory actions requiring environmental assessment in accordance with 10 CFR 51.21. It has determined that this requested action meets the criteria for a categorical exclusion set forth in 10 CFR 51.22(c)(9) and as such, has determined that no irreversible consequences exist in accordance with 10 CFR 50.92(b).

This determination is based on the fact that this change is being proposed as enforcement discretion, to a license issued pursuant to 10 CFR 50 that reflects a requirement with respect to the use of a facility component located within the restricted area, as defined in 10 CFR 20, and the action meets the following specific criteria:

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The proposed action involves no significant hazards consideration. As demonstrated in Section 5.0 of this submittal, this proposed action does not involve any significant hazards consideration.

(i) There is no net change in the types or increase in the amounts of any effluent that may be released offsite. The proposed action does not affect the generation of any radioactive effluent. The proposed action would allow the operation of LSCS Unit 1 at power for a longer period of time one DC electrical power distribution subsystem inoperable. There is no net increase in risk during the additional time period. It is, expected that plant equipment would operate as expected in the event of an accident to minimize the potential for any leakage of radioactive effluents.

(ii) There is no net increase in individual or cumulative occupational radiation exposure.

The proposed action will not change the level of controls or methodology used for processing of radioactive effluents or handling of solid radioactive waste, nor will the proposed action result in any change in the normal radiation levels within the plant.

Therefore, there will be no increase in individual or cumulative occupational radiation exposure resulting from this change.

7.0 PROPOSED COMPENSATORY ACTIONS; The following compensatory actions have been or will be implemented 7.1 Operating crews on-shift during the period of this discretion will be briefed on the current conditions and the provisions of this request.

7.2 The Unit 1, Division 2 DC system voltage will be monitored hourly via a special log.

7.3 The Unit 1, Division 2 battery will be maintained in a fully charged condition (i.e.,

greater than or equal to 128 VDC) by a non-class 1E battery charger that is powered from a non-safety related power source. Provisions have been made to provide a safety related feed to the non-class 1E battery charger, if necessary.

The 128 VDC will be verified by Compensatory Action 7.2.

7.4 Work schedules were reviewed and adjusted as necessary to ensure no other Unit 1 Division 1 or 3 safety-related equipment or remaining Unit 1 Division 2 safety-related equipment will be removed from service for planned maintenance or surveillance testing unless required by the Technical Specifications.

Additionally, the Primary Containment Hydrogen Recombiners, Standby Gas Treatment, and Control Room Area Filtration and Ventilation Air Conditioning Systems will not be removed from service for planned maintenance or surveillance testing unless required by the Technical Specifications during the period of this NOED. It has been verified that there are no scheduled Technical Specification Surveillance Requirements which would render equipment inoperable scheduled for this period. The only Technical Specification Surveillance Requirements that will be performed are non-intrusive data acquisition surveillances.

7.5 Should the temporary non-class 1E charger fail, another temporary non-class 1E charger is available to be promptly installed to maintain the Unit 1 Division 2 battery at a full charge greater than or equal to 128 VDC.

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7.6 The Division 1 and opposite unit Division 2 DC electrical power distribution systems will be protected by posting, shift briefings, discussion at the Plan of the Day meetings, and walkdowns twice per shift of the protected areas by non-licensed operators or field supervisors.

7.7 The Unit 1, Division 1 AC electrical power distribution system will be protected by posting, shift briefings, discussion at the Plan of the Day meetings, and walkdowns twice per shift of the protected areas by non-licensed operators or field supervisors.

7.8 Appropriate operators and electrical maintenance personnel will continued to be briefed on clearance orders and procedures necessary to crosstie Unit 1 and 2 Division 2 DC as a contingency should a LOOP occur on Unit 1.

7.9 Activities will be restricted in the LSCS electrical switchyard to minimize the possibility of an induced loss of offsite power. It has been verified that there are no abnormal weather patterns or conditions expected during the period of this NOED that would adversely impact the LSCS electrical switchyard or Commonwealth Edison electrical power grid. Currently, the Commonwealth Edison electrical power grid is stable and is classified as being in a Green condition.

7.10 Nuclear Oversight independently verified the compensatory actions were established.

7.11 Should any of the parameters specified in this NOED be exceeded (e.g., if voltage oscillations are still observed during post-maintenance testing following replacement of the firing module), TS 3.8.4, Condition E and TS 3.8.7, Condition D will be immediately entered.

8.0 ACKNOWLEDGEMENT OF PLANT OPERATIONS REVIEW COMMITTEE APPROVAL; This request has been reviewed and approved by the LSCS Plant Operations Review Committee (PORC) to meet the requirements of station administrative procedures.

9.0 BASIS FOR CONCLUDING THAT THE NOED CRITERIA ARE SATISFIED AND HOW THEY ARE SATISFIED; EGC has evaluated the requested enforcement discretion against the criteria specified in NUREG-1600. It has been determined that the requested actions meet the NOED criteria for an operating plant. This determination is based on the avoidance of an undesirable transient caused by the shutdown of the reactor as a result of forcing compliance with the Technical Specifications and, thus, minimizes potential safety consequences and operational risks associated with a plant shutdown.

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10.0 MARKED-UP TECHNICAL SPECIFICATION PAGES IDENTIFYING PROPOSED CHANGES (IF APPLICABLE);

Due to the short duration of the request for Enforcement Discretion, a Technical Specification change is not required.

11.0 SEVERE WEATHER OR OTHER EXTERNAL CONDITION DETAILED INFORMATION; This is not applicable for this request.

12.0 OTHER SUPPORTING INFORMATION.

No other supporting information is provided for this NOED.

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