Text

Unit 2; License Amendment Request - One-Time Change to Support Proactive Upgrade of the Emergency - Cooling Pond Supply Piping
	ML21039A756
Person / Time
Site:	Arkansas Nuclear
Issue date:	02/08/2021
From:	Gaston R; Entergy Operations
To:	; Document Control Desk, Office of Nuclear Reactor Regulation
References
	0CAN022102
	Download: ML21039A756 (86)
	v • d • e

Entergy Operations, Inc.

1340 Echelon Parkway Jackson, MS 39213 Tel 601-368-5138 Ron Gaston Director, Nuclear Licensing 10 CFR 50.90 0CAN022102 February 8, 2021 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001

Subject:

License Amendment Request One-Time Change to Support Proactive Upgrade of the Emergency Cooling Pond Supply Piping Arkansas Nuclear One, Unit 1 and Unit 2 NRC Docket Nos. 50-313 and 50-368 Renewed Facility Operating License Nos. DPR-51 and NPF-6 As required by 10 CFR 50.90, Entergy Operations, Inc. (Entergy) hereby requests an amendment for Arkansas Nuclear One, Unit 1 and Unit 2 (ANO-1 and ANO-2) Emergency Cooling Pond (ECP) Technical Specifications (TSs), ANO-1 TS 3.7.8 and ANO-2 TS 3.7.4.1, to allow the ECP to remain operable on a one-time basis for up to 65 days to perform proactive upgrades to the ECP supply piping . This change will allow Entergy the time to perform upgrades on ECP piping from the ECP to the Service Water System (SWS) intake bays prior to a spring outage for each unit.

This proposed amendment request provides a risk-informed assessment of the change as set forth in Regulatory Guides (RG) 1.174, "An Approach for Using Probabilistic Risk Assessment in Risk-Informed Decisions on Plant-Specific Changes to the Licensing Basis," Revision 3, and RG 1.177, "An Approach for Plant-Specific, Risk-Informed Decisionmaking: Technical Specifications," Revision 1.

Approval of the proposed amendment is requested by March 31, 2022. Entergy currently plans to begin upgrade of the ANO-1 ECP piping upgrade 65 days before the start of a future ANO-1 spring outage. Likewise, the ANO-2 ECP piping upgrade is currently planned to begin 65 days before the start of a future ANO-2 spring outage. Once approved, the amendment shall be implemented within 30 days.

The enclosure provides a description and assessment of the proposed changes. In addition, the enclosure concludes that the proposed amendment does not involve a significant hazards consideration. Attachment 1 of the enclosure provides the existing TS pages marked up to

0CAN022102 Page 2 of 2 show the proposed changes. Attachment 2 of the enclosure provides existing TS Bases pages for both units marked up to illustrate the proposed changes, for information only, and will be incorporated in accordance with the plants' TS Bases Control Programs upon implementation of the approved amendment. Attachment 3 of the enclosure provides retyped (revised) TS pages.

The proposed change includes new commitments as summarized in Attachment 4 of the enclosure. Supporting information associated with the aforementioned risk assessment is provided in Attachment 5 of the enclosure. Attachment 6 contains simplified drawings of the temporary pumping system that will be available to supply ECP inventory to the SWS bays during the ECP piping upgrade period.

In accordance with 10 CFR 50.91, Entergy is notifying the State of Arkansas of this Amendment Request by transmitting a copy of this letter and enclosures to the designated State Official.

If there are any questions or if additional information is needed, please contact Riley Keele, Manager, Regulatory Assurance, Arkansas Nuclear One, at 479-858-7826.

I declare under penalty of perjury that the foregoing is true and correct.

Executed on February 8, 2021.

Sincerely,

!"# %"&'(&

Ron Gaston RWG/dbb

Enclosure:

Evaluation of the Proposed Change Attachments to

Enclosure:

1. Technical Specification Page Markups

2. Technical Specification Bases Page Markups - Information Only

3. Retyped Technical Specification Pages

4. List of Regulatory Commitments

5. Probabilistic Risk Assessment

6. Temporary ECP Pump System Configurations - Information Only cc: NRC Region IV Regional Administrator NRC Senior Resident Inspector - ANO NRC Project Manager - ANO Designated State Official - Arkansas

Enclosure 0CAN022102 Evaluation of the Proposed Change

0CAN022102 Enclosure Page 1 of 26 EVALUATION OF THE PROPOSED CHANGE 1.0

SUMMARY

DESCRIPTION The proposed amendment would modify Arkansas Nuclear One, Unit 1 (ANO-1) Technical Specification (TS) 3.7.8, "Emergency Cooling Pond (ECP)," and ANO, Unit 2 (ANO-2)

TS 3.7.4.1, "Emergency Cooling Pond," to permit the ECP to be considered operable for up to 65 days in support of a proactive upgrade on the ECP piping supply to the Service Water System (SWS) intake bays. The requested change involves no significant hazards consideration.

2.0 DETAILED DESCRIPTION 2.1 System Design and Operation Ultimate Heat Sink (UHS)

The UHS sources for both ANO-1 and ANO-2 are the Dardanelle Reservoir and the ECP. While the Dardanelle Reservoir is the preferred source, the Seismic Category 1 ECP is available in the unlikely event of the loss of the Dardanelle Reservoir. The design basis of the UHS is to provide sufficient heat removal for up to 30 days to support a normal shutdown of one unit, a normal shutdown of both units, or a normal shutdown of one unit with a simultaneous emergency shutdown of the other unit assuming a coincident loss of coolant accident (LOCA) on that unit.

As stated above, the UHS consists of two water sources:

a. The ECP with the following associated Seismic Category 1 reinforced concrete structures:

1. Pipe inlet structure,

2. Pipe outlet structure, and

3. SWS intake structure

b. The Dardanelle Reservoir with the associated Seismic Category 1 reinforced concrete SWS intake structure.

The design basis safety functions of the UHS are assured following:

a. The most severe natural phenomena associated with the site location, including earthquake, tornado, flood, or drought, taken individually,

b. Site-related events, such as canal blockage, ice formation, transportation accidents, oil spills, or fires that historically have occurred or that may occur during the plant lifetime, and

c. any single failure of a man-made structure, including failure of the downstream Dardanelle Dam, or any upstream dam or dams.

0CAN022102 Enclosure Page 2 of 26 Both the ECP and the Dardanelle Reservoir feed the SWS pump bays separately. The ECP and associated unit ECP supply pipe provides the necessary water volume to support SWS cooled loads to meet the SWS design basis. The normal intake flow from the Dardanelle Reservoir is provided with traveling screens for debris removal. There is no single failure that could prohibit the UHS from meeting its design basis as required by the General Design Criteria (GDC) of 10 CFR 50, Appendix B, or Regulatory Guide (RG) 1.27, "Ultimate Heat Sink for Nuclear Power Plants," Revision 1 (Reference 1).

Dardanelle Reservoir (Lake Dardanelle)

The Dardanelle Reservoir is part of the Arkansas River navigation project. The project provides a minimum 9-foot navigation depth from the mouth of the Arkansas River at the Mississippi River to Catoosa, Oklahoma, near Tulsa, on the Verdigris River, a distance of more than 500 miles. There are 17 locks and dams in the system. The Dardanelle Dam is located downstream of the ANO SWS intake and was designed and built by the Army Corps of Engineers to withstand the Probable Maximum Flood (PMF) and associated wind effects.

The Dardanelle Reservoir is the primary heat sink for both ANO-1 and ANO-2. The Dardanelle Reservoir is the source of cooling water for the SWS for both ANO-1 and ANO-2 during normal operating conditions. Switchover from the reservoir to the ECP may be accomplished by actuation of the motor operated sluice gates in the SWS intake structure, and either remote manual actuation of the SWS discharge return valves to the ECP if the ECP is used for normal shutdown or automatic actuation of the SWS discharge return valves to the ECP during accident conditions.

The station can obtain the required minimum cooling water from the Dardanelle Reservoir through the canals based on the low water level of 335 ft Mean Sea Level (MSL) in the Reservoir. At any water level below 335 feet in the intake canal, the station cannot be assured of obtaining sufficient cooling water for continuous rated power operation, both units will be shut down, and the water source shifted to the ECP.

Emergency Cooling Pond The Dardanelle Reservoir provides the primary heat sink during normal plant operation while the ECP is a backup Seismic Category 1 source for plant safe shutdown, if necessary, under normal or accident conditions. The ECP serves as a heat sink for simultaneously shutting down both units in the unlikely event of a loss of the Dardanelle Reservoir water inventory or blockage of the intake structure.

Each unit is designed with separate intake and discharge water lines from the ECP to the respective SWS pump bays. The ECP supply to the SWS intake structures is a gravity flow line.

As stated previously, the SWS of either unit can be aligned to discharge to the ECP. The ends of the lines terminating at the ECP are housed in Category 1 structures to prevent blockage of the pipe entrance and outlet. In addition, screens are provided on the ECP intake structure to prevent the inclusion of soil or foreign objects in the water delivered from the ECP.

The ANO-1 ECP TS Bases describes analysis assumptions for the worse case initial conditions considering the loss of the Dardanelle Reservoir. The operating limits are based on conservative heat transfer analyses for the worst-case initial conditions that could be present

0CAN022102 Enclosure Page 3 of 26 considering an ANO-2 design basis accident (DBA) concurrent with a normal shutdown of ANO-1 and a loss of the Dardanelle Reservoir water inventory. The ANO-1 and ANO-2 Safety Analysis Reports (SARs) provide the details of the assumptions used in the analysis. The minimum ECP requirements take into account: 1) water loss from evaporation due to heat load and climatological conditions, 2) fire pump usage, 3) ECP bottom irregularities, 4) water level at the suction pipe at the ECP, and 5) operator action in transferring the SWS discharge from the Dardanelle Reservoir to the ECP.

An indicated level of 5.05 ft corresponds to the TS-required volume of 70 acre-feet. An additional 0.15 ft is appropriate to account for measurement, calculation, and other uncertainties, resulting in the minimum ECP indicated level to ensure a 70 acre-feet volume of 5.2 ft. Operator action is credited in the inventory analysis for a loss of Lake Dardanelle event to transfer the SWS discharge to the ECP. Specifically, SWS returns are transferred to the ECP shortly after the Dardanelle Reservoir loss of inventory event begins and pump suctions are transferred later in the event, depending on pump bay level. In the time frame between the transfer of the SWS returns and the later transfer of SWS suctions to the ECP, Dardanelle Reservoir water is transferred to the ECP, increasing level by at least 4.5 inches. This additional water is required, along with that maintained in the ECP, to ensure a 66.9-inch depth, which in turn ensures a 30-day supply of cooling water. The ECP is designed in accordance with RG 1.27, which requires a 30-day supply of cooling water.

Service Water System The SWS provides required cooling water flows to Emergency Safeguards Features (ESF) equipment served by the system, as well as to various non safety-related portions of the plant.

Structures, systems, and components (SSCs) important to safety are cooled by the SWS. Each unit's SWS is designed with two redundant 100% capacity trains and three 100% capacity pumps which can be operated from offsite power or from onsite emergency power. The SWS consists of Seismic Category 1 and non-Seismic Category 1 portions. Non-Seismic Category 1 portions of the system are automatically isolated from the system upon receipt of appropriate ESF actuation signals.

The normal and preferred SWS source of water during normal and accident conditions is the Dardanelle Reservoir. The flow from the reservoir is provided with traveling screens for debris removal. When the Dardanelle Reservoir is not available, the ECP provides the necessary cooling water to the SWS.

Normal and Emergency Operation During normal power operation, the SWS is supplied by the preferred source, the Dardanelle Reservoir. However, when the Dardanelle Reservoir is not available the SWS will be temporarily supplied from the ECP. During emergency operations (DBA) the SWS is expected to remain supplied by the preferred Dardanelle Reservoir source. However, in the case of a failure of the downstream Dardanelle dam, the ECP will provide the UHS function.

The SWS components inside the intake structure include the SWS pumps and motors, basket strainers, pump discharge piping and associated valve operators, intake sluice gates and the gate operators, and sodium bromide/sodium hypochlorite injection piping. The intake structure also contains the bar gates, traveling water screens, prescreens, and screen wash water piping.

0CAN022102 Enclosure Page 4 of 26 2.2 Current TS Requirements ANO-1 has previously converted to the improved standard TS of NUREG-1430, "Standard Technical Specifications Babcock and Wilcox Plants" (Reference 2). ANO-2 has not converted to the improved standard TS of (NUREG-1432, "Standard Technical Specifications Combustion Engineering Plants" (Reference 3). The ANO-2 TSs are based on NUREG-0212, "Standard Technical Specifications for Combustion Engineering Pressurized Water Reactors" (Reference 4).

ANO-1 ECP TS 3.7.8 requires the ECP to be operable in Modes 1, 2, 3, and 4. If the ECP is inoperable for reasons other than a degradation of the ECP structure, the unit is required to be placed in Mode 3 within 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and in Mode 5 in 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months .

ANO-2 ECP TS 3.7.4.1 also requires the ECP to be operable in Modes 1, 2, 3, and 4. If the ECP is inoperable for reasons other than a degradation of the ECP structure, the unit is required to be placed in Mode 3 within 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and Mode 5 in the following 30 hours3.472222e-4 days 0.00833 hours 4.960317e-5 weeks 1.1415e-5 months .

2.3 Reason for the Proposed Change Entergy Operations, Inc. (Entergy) has submitted a relief request to the NRC for approval to use Carbon Fiber Reinforced Polymer (CFRP) at ANO to proactively upgrade the ECP supply piping from the ECP to the SWS intake bays. The proactive upgrade to the ECP piping is currently planned to take place 65 days before the start of a spring refueling outage for each unit individually.

While the ECP piping is being proactively upgraded, the ECP will be inoperable with respect to regulatory compliance. Currently, both the ANO-1 and ANO-2 TSs require a shutdown when the ECP is inoperable. The time needed to install the CFRP far exceeds normal refueling outage durations. To reduce an unnecessary burden of an extended plant shutdown, Entergy requests approval of a TS amendment to allow the ECP to be considered operable, based on a temporary pumping system (discussed later) for up to 65 days while the respective proactive upgrade to the ECP supply piping for each unit is taking place.

2.4 Description of the Proposed Change The proposed change to ANO-1 and ANO-2 TSs will add a Note to the Limiting Condition for Operation (LCO) that would allow the ECP to be considered operable on a one-time basis for up to 65 days during the proactive upgrade to the ECP supply piping, provided a loss of the Dardanelle Reservoir is not in progress and provided a temporary pumping system is available that is capable of supplying the SWS from the ECP. The following LCO Note is being proposed for ANO-1 and ANO-2.

The ECP may be considered OPERABLE on a one-time basis for up to 65 days during upgrade of the ECP supply piping to the SW System intake bays provided:

a. A loss of Lake Dardanelle event is not in progress, and

b. A temporary pumping system is capable of supplying the SWS from the ECP. The temporary pumping system may be unavailable for testing or necessary maintenance provided its availability is restored within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months .

0CAN022102 Enclosure Page 5 of 26

3.0 TECHNICAL EVALUATION

3.1 Background

The supply piping between the ECP and the SWS intake bays are experiencing natural degradation due to microbiological influenced corrosion (MIC). As a proactive measure, Entergy is planning to perform upgrades to the piping. The planned upgrade involves using a Carbon Fiber Reinforced Polymer (CFRP) Composite System wrap on the internal surfaces of the ECP supply piping. Entergy submitted a relief request on July 15, 2020, to allow use of the CFRP in buried piping (Reference 5).

The length of ECP supply piping for upgrade is approximately 2300 ft for each unit. The upgrade is currently scheduled to take 60 days for each unit. During the upgrade, the respective units ECP supply piping will be unavailable and, therefore, the ECP will be considered inoperable. The current TS for each unit requires the ECP to be restored to an operable status or the unit shutdown to Mode 3 within 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months . Entergy prefers to perform the proactive upgrade to the ECP supply piping while online and prior to a spring refueling outage.

Therefore, Entergy is requesting an amendment to the ANO-1 and ANO-2 TSs to allow the ECP to remain operable for up to 65 days prior to a spring refueling outage of each unit. The extra five days provides some margin to account for unforeseen circumstances, with the respective refueling outage providing any additional time that may be required to complete the CFRP installation. During this 65-day period, supply to the SWS will be from Lake Dardanelle (normal alignment); however, a temporary above ground engine-driven pumping system will also be made available to supply the SWS bays from the ECP should a loss of Lake Dardanelle occur.

If during the 65-day piping upgrade a loss of Lake Dardanelle event were to occur, the ECP will be considered inoperable and the Actions of respective unit's ECP LCO applied (i.e., the respective unit will be required to be in Mode 3 in 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and Mode 5 in 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months ).

For the purposes of the proposed LCO Note, a loss of Lake Dardanelle is considered an event that renders the Dardanelle Reservoir unavailable for an extended period of time, likely with no known time for recovery. Such events include failure of the downstream Dardanelle Dam, notification from the Army Corps of Engineers of more than a momentary draw down of lake level below 335 ft MSL, a major oil or chemical spill which renders Lake Dardanelle unfit for use to support cooling of station equipment, or any other event that would result in more than temporary lowering of the intake canal below 335 ft MSL.

There are other events, especially a phenomenon referred to as "shad runs", that can occur in the late fall and early winter months which require operator action to ensure an inventory source remains available to the SWS bays. Historically, the intake traveling screens have occasionally become clogged due to large shad fish kills when rapid changes to lake temperatures occur during the initial winter months. To prevent/limit these occurrences, Entergy installs fish nets (shad nets) at the entrance to the ANO intake canal from the Dardanelle Reservoir during the winter to capture shad should a temperature transient occur in the lake and cause a fish kill.

The shad nets are deployed as delineated in the environmental permit to minimize the amount of shad that wash into the SWS intake canal. Abnormal Operating Procedures (AOPs) provide the actions necessary to respond to shad runs and other temporary bay level events, which may include temporarily aligning one or more SWS bays to the ECP. Such temporary events that are appropriately addressed by station procedures are not considered loss of Lake Dardanelle events for the purposes of the proposed LCO Note.

0CAN022102 Enclosure Page 6 of 26 The intent of the "loss of Lake Dardanelle" portion of the LCO Note is to ensure prompt action is taken to enter the shutdown actions of the respective ECP TS should the Dardanelle Reservoir experience an event requiring the SWS bays to be transferred to the ECP for an extended period of time. This is considered a conservative action even though the temporary pumping system will be capable of supplying all safety-related SWS loads of both SWS loops (the accident analyses assumes only one SWS loop is available) for the unit undergoing the ECP piping upgrade. However, based on the temporary pump capability, it is not necessary to require immediate entry into the ECP TS shutdown actions for temporary level deviations such as during recovery from shad runs. Station procedures provide the necessary actions, which may include a shutdown of the unit depending on the circumstances present, for conditions that may require temporary use of the ECP temporary pumping system to supply the SWS bays. of this enclosure provides a markup of the TS Bases which includes the appropriate Operator guidance with respect to proper application of the proposed LCO Note.

3.2 Justification As stated previously, Lake Dardanelle is the preferred source for the SWS and is normally aligned to the SWS unless maintenance or surveillance testing is required. A review of station operator logs for the past 5 years determined the SWS has been aligned from the ECP, while in Modes 1, 2, 3, or 4, approximately 1% of the time excluding surveillance testing.

Lake Dardanelle is a reservoir formed by the Dardanelle Lock and Dam. The dam is controlled by the Army Corps of Engineers. Failure of the dam is considered to be practically impossible (although assumed to occur in the safety analysis). It is designed to withstand the Design Basis Earthquake (DBE) of 0.2g, probable maximum flood, and wind effects.

Entergy will install a temporary pumping system to supply water from the ECP to the SWS intake bays as a backup to Lake Dardanelle to ensure inventory can be supplied to the SWS if a loss of Lake Dardanelle occurs (as defined previously) or if temporary use is needed for non-loss of Lake Dardanelle events. See the Contingency Section below for more details on the temporary pumping system.

A probabilistic risk assessment (PRA) was performed to determine the risk to each unit during the upgrade (see Section 3.3 and Attachment 5). The probabilistic evaluations found that the risk increase to the plant during the period of the ECP piping upgrade with the temporary pumping system available are within the NRC risk increase criteria. The most limiting PRA case that maintains the risk increase less than 1 X 10-6 for Core Damage Frequency (CDF) and less than 1 X 10-7 for Large Early Release Frequency (LERF) shows that the amount of time the normal ECP supply can be unavailable with the temporary pumping system available is:

85 days (CDF) and 99 days (LERF) for ANO-1, and 75 days (CDF) and 88 days (LERF) for ANO-2.

Following are discussions of the contingencies (modeled in the PRA) and the defense in depth measures (not modeled in the PRA) that will be taken by Entergy to ensure that an acceptable safety margin is maintained during the ECP supply piping upgrade. The two contingency requirements included in the proposed LCO Note are mandatory for utilizing the TS Note and allowing the ECP to be considered operable during the ECP upgrade period. If either of the contingencies are not met, the affected unit will be required to immediately enter the applicable ECP TS Action(s) (6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months to be in Mode 3 and 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months to be in Mode 5). The defense in depth measures that ANO will perform enhances the margin to safety and are described later.

0CAN022102 Enclosure Page 7 of 26 Contingencies A temporary ECP diesel-driven pumping system will be utilized as a compensatory measure in the highly unlikely event the preferred UHS source (Dardanelle Reservoir) is lost or becomes temporary unavailable (as discussed previously) during the proactive upgrade of the ECP supply piping. Proper SWS bay level will be maintained by the pump using a mechanical float control valve to regulate flow from the temporary ECP pump. The temporary pumping system will be sized to provide adequate flow to support the safety-related equipment of both trains of the SWS to safely shutdown the unit under normal or accident conditions (the other ANO unit will maintain full ECP flow capacity from its normal ECP suction line). In accordance with the LCO Note, the temporary pumping system may be removed from service for testing or to support any necessary maintenance provided its availability can be restored within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months , consistent with the TS allowed time to restore an inoperable SWS loop. In both cases, single failure criterion would not be met and, therefore, time to recover from the condition is appropriately limited. This 72-hour allowance in which the temporary pumping system may be unavailable is considered reasonable since the likelihood of a loss of the Dardanelle Lake or SWS bay inventory event occurring in a 72-hour period during the 65-day ECP piping upgrade is low.

Furthermore, if an external flood event is projected to exceed an elevation of 350 ft MSL, the ANO-2 buried ECP piping upgrade activities will be terminated and the ECP piping closed to restore a flow path from the ECP to the ANO-2 SWS pumps within 48 hours5.555556e-4 days 0.0133 hours 7.936508e-5 weeks 1.8264e-5 months . This is prudent since the ANO-2 SWS sluice gate control circuits are not designed to remain available during post-flood conditions. An external flood event is not of concern for ANO-1 since the portions of the control circuits for the SWS bay sluice gates susceptible to flood damage are located above the Maximum Permissible Flood (MPF) level described in the SAR.

The following measures in support of the temporary ECP pumping system are considered regulatory commitments and will be maintained during the 65-day ECP piping upgrade. These commitments will expire at the end of the 65-day preventative maintenance window.

The temporary pump will be tested and minimum flow requirements verified prior to removing the installed ECP supply piping from service.

The Army Corps of Engineers will be briefed on the ECP piping upgrade activities and on the increased sensitivity of Lake Dardanelle level during the period of the ANO ECP piping upgrade. The Army Corps will be requested to minimize any activity and provide advanced notification of activity that could impact the lake level or amount of debris in the lake.

The 65-day allowance for the ECP to remain operable during the ECP supply piping upgrade will be applied only prior to a spring outage to provide additional margin to the TS maximum ECP temperature limit.

The temporary pump system will be started to ensure its continued availability on a weekly basis.

Personnel trained to start the pump will be dedicated and onsite 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months a day, stationed in reasonable proximity of the pump, during the ECP piping upgrade when the ECP temporary pump is being relied upon as a backup for the Dardanelle Reservoir, with direct communications with the respective ANO Control Room.

0CAN022102 Enclosure Page 8 of 26 During the ANO-2 ECP piping upgrade, equipment will be staged near each ECP pipe opening to allow pipe closure, within 48 hours5.555556e-4 days 0.0133 hours 7.936508e-5 weeks 1.8264e-5 months , when external flooding is projected to exceed 350 ft MSL.

No elective maintenance or elective testing will be performed that could challenge the Dardanelle Reservoir SWS suction source.

The SWS pumps, bays, traveling screens, and sluice gates that are important for ensuring cooling water is provided to the supported SSCs will be given protected train status.

The intake traveling screens will be inspected for debris and general physical condition at least once per shift.

The accessible portions of the temporary ECP system piping will be inspected weekly.

Fish nets will be installed in the Dardanelle Reservoir SWS intake canal when required by existing winter operations procedural guidance and inspected for any gross physical damage or large quantities of debris twice a week, weather permitting, to ensure the nets remain intact and capable of performing the intended function.

An adequate fuel supply will be maintained to supply the temporary pump for approximately 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months of continuous operation.

At least once per week, a briefing will be conducted for applicable personnel to ensure individuals remain cognizance of the cues that would prompt Operator action to start the temporary pumping system and open the discharge valve.

The ECP level will be maintained 5.5 ft during the 65-day preventative maintenance window.

The first three items above are performed prior to initial entry into the 65-day ECP piping upgrade window. Because unforeseen circumstances could arise that may temporarily prevent meeting one of the other ongoing commitments during the maintenance window, Entergy intends to consider the ECP to remain operable in such an event provided action is taken to restore the commitment without delay. This is considered reasonable since failure to meet one or more ongoing commitments does not immediately render the temporary ECP pumping system unavailable. The markup of the respective TS Bases included in Attachment 2 of this enclosure provides the Operator guidance necessary to properly apply the proposed LCO Note.

Plant Operation with Application of the LCO Note During normal power operation, the SWS is expected to be supplied by the preferred source, the Dardanelle Reservoir. If the Dardanelle Reservoir is lost (as defined previously) during the 65-day piping upgrade, a unit shutdown will be required. The temporary ECP pumping system will be capable of supplying the SWS with the necessary flow to facilitate a normal plant shutdown or a shutdown during accident conditions.

During shutdown operations (Mode 5) the ECP is not required to be operable by the TSs and the SWS is expected to be supplied by the preferred source, the Dardanelle Reservoir.

However, when needed for shutdown risk mitigation, the ECP is maintained available as a backup SWS supply source, except for short periods during the outage when surveillance testing is performed or maintenance is required. The temporary system will be designed to provide adequate flow to support shutdown operation.

0CAN022102 Enclosure Page 9 of 26 With respect to shutdown operations, both unit's ECP TSs are applicable only in Modes 1, 2, 3, and 4. Any unit shutdown that may occur during the 65-day ECP piping upgrade window requiring entry into Mode 5 would render the LCO Note no longer applicable. To support restart of the unit during the 65-day ECP piping upgrade period, the TS Bases is modified to provide Operator guidance for reapplying the proposed LCO Note upon entry into Mode 4 from Mode 5.

Any subsequent application of the LCO Note following initial application requires the 65-day time period to have commenced retroactive to the initial application of the LCO Note. For example, if a unit shutdown occurs 10 days following the commencement of the ECP piping upgrade and the unit remains in Mode 5 for 12 days, the proposed LCO Note may be reapplied upon entry into Mode 4 during plant restart; however, the time remaining in the original 65-day ECP piping upgrade window has now been reduced to 43 days (65 12 = 43).

During emergency operations (DBA), the SWS is expected to be supplied by the preferred source, the Dardanelle Reservoir. However, in the case of a failure of the Dardanelle dam or intake canal blockage, the ECP can provide the UHS function. The temporary system will be designed to provide adequate flow to both SWS trains to remove design basis heat loads during emergency operation. The ECP temperatures will be lower during the ECP supply piping upgrade because the modification will be performed during the pre-spring months, which will provide additional margin to the current design basis 100 °F maximum ECP temperature.

Based on the SAR, the capability of transferring SWS suction from Dardanelle Reservoir to the ECP within two hours of notification of a potential failure of the Dardanelle Dam must be maintained. To ensure this capability, a formal agreement between Entergy and the U.S. Army Corps of Engineers has been previously established (reference ANO Emergency Plan, Section 1.2.1.3) to ensure ANO is promptly notified of an imminent loss of Lake Dardanelle.

Existing procedures direct Operators to transfer the suction of the SWS pumps from the reservoir to the ECP if bay level drops below 333 ft MSL. This is accomplished by first initiating manual closure of the Dardanelle Reservoir sluice gate and then opening the ECP supply sluice gate once level in the SWS bay starts to drop. This sequence minimizes ECP inventory loss to the lake. The same sequence would be followed when the temporary system is in place but rather than opening the ECP sluice gate, the temporary pump would be started since the pump discharges directly into the respective SWS pump bay.

Temporary Pumping System The temporary pumping system will consist of a diesel-driven pump, fuel tank, suction strainer, high density polyethylene (HDPE) and carbon steel (CS) suction and discharge piping, and valves to control flow. The pump and fuel tank will be located adjacent to the ECP with a containment system to prevent any potential fuel spill from entering the ECP. The fuel tank capacity will provide sufficient fuel supply to run the pump for approximately 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months without refueling.

To minimize debris from entering the system, temporary strainers will be installed in the ECP with a screen mesh equivalent to the existing ECP intake screens. The strainers will be sized to meet the pump net positive suction head (NPSH) requirements at the current design basis ECP temperature and level. While the temporary ECP system is in place, stop logs will be installed in the ECP intake to allow access to the ECP pipe. The stop logs will be designed to withstand seismic, hydrostatic pressure, and appropriate wind loads.

0CAN022102 Enclosure Page 10 of 26 The HDPE piping will be run from the submerged strainer up to the pump skid and then generally above ground to the SWS intake building. The routing has been chosen to minimize potential tornado missile damage by locating the pipe adjacent to robust structures. The pipe will transition to CS prior to entering the SWS intake building through existing doorways and then be routed along the floor down into two of the three SWS pump bays through existing openings. The pump bay without the temporary ECP pipe will be drained to allow upgrade of the section of the buried ECP piping entering the bay.

Once the upgrade is completed for a given bay, it will be reflooded and the temporary ECP pipe to the bay will be installed and tested. Each of the other two bays will then be taken out of service one at a time, drained, and have its buried ECP piping upgraded. Two SWS pump bays will have temporary ECP supply available at all times. The SWS pump bay level will be maintained by a flow regulating valve installed in the temporary ECP pipe feeding each pump bay actuated by a mechanical float installed in the pump bay. To improve the temporary system reliability, external electrical power will not be required for the system. The only device requiring electrical power will be the engine control panel which is supplied by the engine DC battery.

Exposure to Low Temperatures The temporary ECP system pump and piping will be exposed to ambient conditions during the winter/early spring season. This area of Arkansas can experience temperatures below freezing for several days during this time period. To preclude freezing within the temporary ECP system, temporary heating to the pump area, and insulating the piping or establishing sufficient minimum flow through the piping will be performed.

Seismic Considerations Although the temporary ECP supply system does not fully meet the quality, seismic, or tornado missile design basis, the temporary ECP pump and piping will be restrained or protected to ensure functionally during high wind and seismic events.

The temporary ECP pumping system is a commercial non-safety related system being installed as a compensatory measure. However, to provide high confidence that the system to remain functional during a seismic event, the system piping and equipment anchorage will be analyzed to withstand seismic loads generated from the current ANO maximum DBE ground acceleration of 0.20g. The seismic capability of the temporary equipment will be established through qualitative evaluation using generic industry data compared with the ANO DBE. Restraints will be provided, if necessary, such that the system will remain functional during a seismic event.

The temporary pump skid and wind barriers will be located far enough from the ECP edge such that the pond embankment will not be affected by the skid during a seismic event.

Wind Considerations The wind load is considered minimal due to the shape factor of the pipe and that the pipe will be on the ground or inside the intake structure. To reduce the risk of wind damage to the pump and fuel tank, both will be enclosed by barriers. The barriers around the pump will have sufficient wind loading capacity to resist the ANO-2 80 mph maximum wind speed which is bounding for the two units.

The temporary piping and equipment will be restrained to limit movement and stresses due to wind, seismic, and thermal expansion within ASME code or Plastic Pipe Institute limits.

0CAN022102 Enclosure Page 11 of 26 Fire Considerations The diesel and electric fire pumps take suction from the ANO-1 "A" and "C" SWS pump bays, respectively. When the "A" or "C" SWS pump bay is removed from service, the corresponding fire pump will also be removed from service. An alternate fire water supply source will be established for the out of service fire pump as required by the ANO-1 and ANO-2 Technical Requirements Manuals (TRMs). The overall fire risk to the site with respect to the temporary pump system has been evaluated in accordance with NFPA 805 implementation methodology as defined in the Fire Hazards Analysis (FHA). See Attachment 5 for the evaluation of fire risk due to the temporary ECP pump system. In order not to increase the combustible loading in the SWS intake building and potentially affect redundant SWS trains, the portion of the temporary pipe routed in the SWS intake building will be made from non-combustible material.

Defense-in-depth and safety margins for the fire systems will be maintained by utilization of an alternate fire water supply when the fire pump is removed from service.

Intake Building Considerations During installation and use of the temporary ECP piping, one or both of the SWS intake building access doors will be removed to allow routing the temporary ECP pipe into the SWS bays.

Temporary security measures will be in place to limit access to the building. Temporary closure of the door opening will be provided, when needed, to maintain ambient temperatures inside the Intake Building during extreme cold weather conditions.

External Flood Considerations The existing maximum design flood level for the ANO site is 361 ft MSL. The new piping will be routed and constrained such that it does not alter the external flood level or cause major redirection of flood drainage. The temporary ECP pump will be located below the maximum flood level and will not be available to provide ECP supply to the SW pump bays during an external flood. Due to adverse impact to the ANO-2 sluice gate control circuits during a flooding event, SWS pump suction is transferred to the ECP prior to flood level entering the SWS Intake Building. The MPF flood analysis as discussed in the SAR concludes that the rise in the Dardanelle Reservoir level would be relatively slow and predictable over a 5-day period. When the Dardanelle reservoir reaches the flood stage (345 ft MSL), ANO AOPs require the installation of flood barriers and the sealing of openings that could allow flood water to affect SSCs required for safe shutdown. In support of the revised ECP LCO, equipment will also be removed from the buried ECP pipe, the access opening closed, and the buried ECP pipe returned to service to provide flow, if needed, to the SWS pump bays from the ECP.

Internal Flood Considerations The temporary ECP piping will be supported to resist the current ANO design basis seismic ground response of 0.20g. The piping will not be a new source of flooding due to pipe breaks for ANO-1 since the ANO-1 licensing basis does not include evaluation of breaks in seismically qualified piping. However, a pipe break is considered a new source of flooding for ANO-2 because the ANO-2 licensing basis does include evaluation of seismically qualified pipe breaks.

The existing design basis evaluations related line breaks in the SWS Intake Building demonstrates that existing floor openings on the 354 ft elevation have adequate capacity to drain break flow and mitigate flooding before it can impact safety related equipment. All components of ESF equipment located in the intake structure whose operation could be

0CAN022102 Enclosure Page 12 of 26 degraded by flooding have been located above the 361 ft level of the intake structure. Existing floor openings have sufficient margin to mitigate flooding from pipe breaks even with the ECP temporary piping reducing the flow area through the floor opening into the respective SWS bay such that the water level at the 354 ft elevation remains well below the 361 ft PMF level.

Testing and Preparedness Entergy will test the temporary ECP pump and piping to ensure it can deliver the minimum required flow to the SWS in the time required for starting the system. The transfer of SWS pumps to ECP suction is currently designed to be a manual action. The manual startup of the temporary ECP supply pump/piping system has also been shown to be acceptable (see Section 3.4 and Attachment 5). Weekly starts of the temporary ECP pump will be performed to ensure continued pump reliability. In addition, weekly visual inspections of the temporary above grade ECP piping will also be completed to verify the continued integrity of the temporary system.

A dedicated individual trained to operate the pump will be stationed onsite when the temporary pump is being relied upon as a backup to the Dardanelle Reservoir. Having a dedicated individual available to start the pump and initiate flow will minimize the pump start delay time, minimizing the time in which inventory reaches the SWS intake bays.

FLEX The existing diverse and flexible coping strategies (FLEX) utilize five separate tanks as potential sources of makeup water to the Spent Fuel Pool (SFP) and Qualified Condensate Storage Tank (QCST). If none of the tanks are available due to wind damage, two alternate sources are provided. The first method uses the diesel fire pump taking suction from the associated SWS bay. The second method installs a portable pump at the ECP taking suction with hoses from the ECP. The ECP temporary pump, having enhanced wind protection features, can be utilized for refilling the QCST in addition to the established FLEX features. The alternate equipment haul path will be blocked in two places by the temporary HDPE pipe where it crosses the haul road. The primary haul path is not affected. Existing FLEX deployment strategies account for potential large debris blocking a haul path and the existing FLEX haul equipment has the resources and capability to remove the section of HDPE pipe crossing the road if the alternate haul path is needed. The FLEX strategies will still provide an indefinite coping capability to prevent damage to the fuel in the reactors and SFPs and to maintain the containment function by using installed equipment, on-site portable equipment, and pre-staged off-site resources.

Summary of Measures to Increase Operating Margin The ECP upgrade will take place during the winter and early spring. During this time the lake and ECP temperatures will be lower than during other parts of the year. This maximizes the cooling capability of the SWS and reduces the heat removal burden on the ECP.

In addition, performing the work just prior to a spring outage will ensure the 65 days are not exceeded since the unit is scheduled to shutdown for the spring refueling outage at the end of 65 days even if the upgrade is not completed. In Modes 5 and 6, the ECP is not required to be operable. The unit would not be allowed to startup from the refueling outage thereafter until the buried ECP supply line is returned to service and the line is capable (i.e., operable) of supplying the required ECP volume to the SWS intake bays.

0CAN022102 Enclosure Page 13 of 26 The current ECP volume TS limit is 70 acre-ft (a level of 5.2 ft); however, the level is normally maintained 5.5 ft. During the ECP supply piping upgrade, this level range will be maintained, providing significant margin to the TS limit.

In addition, TS surveillance requirements (SRs) and PMs that have the potential to require SWS suction to be transferred to the ECP (including the activities associated with sluice gates, strainers, screens, etc.) will be performed, where possible, prior to the start of the ECP piping upgrade or after the ECP piping upgrade is completed. The SWS pumps, bays, traveling screens, and sluice gates that are important for ensuring cooling water is provided to the supported SSCs will be given protected train status. This will lessen the likelihood of inadvertent loss of required equipment.

Traveling screens will be inspected for debris and general physical condition at least once per shift. This will ensure proactive cleaning of the screens to ensure excessive debris does not hinder SWS flow from Lake Dardanelle. The shad nets will also be inspected for any gross physical damage or large quantities of debris twice a week, weather permitting, to ensure the nets remain intact and capable of performing the intended function.

An opening is provided in the net to allow local public access to the shore area. Prior to 2018, the opening was located upstream of the intake canal entrance. The normal lake and canal current would direct some of the dead fish through the net opening and into the canal. To prevent this, in 2018, the net opening was moved downstream from the canal opening so that any dead fish would either float past the opening or onto shoreline. As discussed previously, for the purposes of the proposed LCO Note, events that temporarily clog a SWS traveling screen or pump strainer are not considered a loss of Lake Dardanelle event. Station procedures dictate actions to recover from such events and provide limits for when a unit shutdown may be required should recovery actions be unsuccessful. These events are not expected to be long-lived as would be the case for the analyzed loss of Lake Dardanelle event. The proposed TS Bases changes supporting the subject LCO Note provides appropriate Operator guidance (see Attachment 2).

3.3 Risk Assessment Summary As discussed in RG 1.177 the NRC has identified a four-element approach to evaluating proposed changes to a plants design, operations, and other activities that require NRC approval. The four elements are as follows:

Element 1: Define the Proposed Change (Sections 2.1, 2.2, 2.3, 2.4, 3.1, 3.2, and 3.3)

Element 2: Perform Engineering Analysis (Section 3.3 and Attachment 5)

Element 3: Define Implementation and Monitoring Program (Sections 3.1 and 3.2)

Element 4: Submit Proposed Change (ANO Letter 0CAN022102)

A risk assessment (Attachment 5) was performed to support this license amendment request.

The basis of the risk assessment evaluated the 65-day period during the ANO ECP supply piping upgrade on one ANO unit at a time, in which the normal ECP system would be taken out of service and replaced with a temporary system to supply the SWS bays. While the proposed change does not involve TS completion times or surveillance frequencies, RG 1.177 and, by

0CAN022102 Enclosure Page 14 of 26 reference, RG 1.174 were used to determine the acceptability of the risk impact with respect to meeting the intent of the Commissions Safety Goal Policy Statement. The information below is a summary of the information in the PRA Report located in Attachment 5 of this submittal.

PRA Model As modeled in the PRA, the ECP provides a shared heat sink between ANO-1 and ANO-2, utilizing each units SWS, for removing operating heat from safety-related components and decay heat from the reactor core and transferring it the ECP. The ECP system normally provides the SWS bays by gravity flow via mostly buried piping. During the 65-day ECP supply piping upgrade, the SWS will be supplied from the ECP with a temporary pumping system with the piping above ground.

The risk assessment considered the following features of the temporary pumping system:

A skid-mounted, diesel-driven pump (DDP), with an attached secondary fuel tank (SFT),

located close to the ECP intake and shoreline and surrounded by the DDP structure consisting of stacked concrete blocks or other suitable barriers; A strainer on the DDP suction located near the bottom of the ECP, with a check valve and manually operated butterfly discharge isolation valve near the DDP; A total of about 3000 of HDPE piping running above ground from the ECP to the DDP suction and then from the DDP discharge to the intake structure; Prior to entering the intake structure for each unit, the piping branches to separate feeds for SWS pump bays A and C, then transitions to carbon steel to supply the pump bays from above; One locked-open manual butterfly isolation valve to each SWS pump bay (not modeled);

and One mechanical float-actuated level control valve for controlling level in each associated SWS pump bay.

Engineering Analysis For a one-time change to a TS requirement, RG 1.177 identifies the risk metrics of merit to be the Incremental Conditional Core Damage Probability (ICCDP) and the Incremental Conditional Large Early Release Probability (ICLERP). These risk metrics account for the limited time in which the plant configuration change exists. In particular, the guidance in Sections 2.4 and 2.5 of RG 1.174, for annualized risk expressed as the change in Core Damage Frequency (CDF) and the change in Large Early Release Frequency (LERF), is not applicable because the amendment request does not propose a permanent TS change and does not result in a permanent change to the CDF or LERF.

The risk assessment comprised a blend of qualitative, quantitative, and reasonably bounding analyses.

0CAN022102 Enclosure Page 15 of 26 Transition risk was not addressed because no change is proposed to any requirement for a controlled shutdown (i.e., the time allocated to transition through hot standby to hot shutdown or to cold shutdown) after the ECP was removed from service (inoperable).

Shutdown risk was addressed because ECP operability is proposed to be redefined, and the ECP is a system potentially needed for decay heat removal.

The risk assessment focused on increased contributions to at-power risk because the conditions under which the ECP would be considered operable are proposed to be modified while remaining at-power.

The at-power (ICCDP) (or at-power ICLERP) was calculated as the respective risk increase between a conditional configuration and a baseline configuration for the duration of 65 days that is proposed by the request.

For Internal Events, Internal Flood, and Internal Fire, each respective at-power ICCDP (or at-power ICLERP) was based on the quantification of a suitable PRA model for that hazard.

For seismic and high winds hazards where no suitable PRA model exists, each respective at-power ICCDP (or at-power ICLERP) was determined from a reasonably bounding analysis based on a simplified hazard model of a Loss of Offsite Power (LOOP) with no recovery and with the Alternate AC Diesel Generator (AACDG) and electrical bus crosstie postulated as representative surrogate failures.

The risk assessment considered other hazards from the Individual Plant Examination for External Events (IPEEE) Program.

Refer to Attachment 5 for more details on the specific treatment of the above features and the associated risk modeling, and the calculated risk measures including uncertainty and sensitivity analysis.

An evaluation of the risk impacts and the compensatory actions that could mitigate the risk increase is as follows. As a bounding configuration, the risk assessment assumed the SWS pump bay B and SWS pump B would be out of service for the entire 65-day period.

The following compensatory actions were not specifically credited in the PRA but would mitigate some portion of the associated risk.

A weekly briefing would maintain responsible personnel cognizant of the cues that would prompt operator action to start the DDP and open the discharge valve.

Weekly start testing of the DDP would promote reliable execution of the operator action to start the DDP.

A weekly walkdown of the temporary pumping system would ensure the normally locked open or locked closed manual isolation valves are maintained in the proper alignment.

See the full report in Attachment 5 for the evaluation of Uncertainty and Sensitivity Analysis.

0CAN022102 Enclosure Page 16 of 26 Conclusion The comparison of the change in plant risk relative to the acceptance guidelines shows that ANO-1 and ANO-2 maintain an ICCDP less than 1 X 10-6 and an ICLERP less than 1 X 10-7.

Therefore, the risk impact of the proposed one-time TS change was demonstrated to be acceptable based on the guidance in RG 1.177. This provides reasonable assurance that the risk increase is small and consistent with the intent of Commissions Safety Goal Policy Stations for the operations of nuclear power plants.

The most limiting PRA case that maintains the risk increase less than 1 X 10-6 for CDF and less than 1 X 10-7 for LERF shows that the amount of time the normal ECP supply can be unavailable with the temporary pumping system available is:

85 days (CDF) and 99 days (LERF) for ANO-1, and 75 days (CDF) and 88 days (LERF) for ANO-2.

Because an extended time interval between NRC approval of the LAR and the actual upgrade of the ECP supply piping may exist, Entergy will reassess the risk impact against the acceptance guidelines for a small risk increase as defined in RG 1.177 (ICCDP < 1E-6 and ICLERP < 1E-7) prior to entry into the 65-day preventative maintenance window. If either criterion is not met, Entergy will inform the NRC before proceeding. This is considered a regulatory commitment and is include in Attachment 4 of this enclosure.

3.4 Defense-in-Depth Principles In addition to the contingencies and proactive measures to prevent anomalies (discussed above), the Work Management Program and the associated procedures and programs that implement the Maintenance Rule Program provide for controls and assessments to ensure system reliability, establishing the defense-in-depth principles described in RG 1.177 and RG 1.174. The following elements, as identified in RG 1.174, Section 2.1.1.2, have been evaluated. The impact of the proposed change on these elements is as follows:

Preserve a reasonable balance among the layers of defense.

Prevention of core damage depends on the ability to continuously remove decay heat after an initiating event with the UHS. During the ECP piping upgrade, if a DBA were to occur, the reservoir would remain available and provide a source of cooling to the SWS for decay heat removal. Should a failure occur in the Lake Dardanelle dam, the temporary ECP pumping system would be available to supply cooling water to the SWS.

The temporary ECP system will be sized to deliver the design basis SWS flowrate to support two loops of SWS operation during normal shutdown or emergency shutdown (DBA). A dedicated person trained on operating the temporary pump system will be onsite 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months a day with direct communication to the Control Room during the ECP piping upgrade to start the pump when required such that the existing operations staff will not be challenged with additional actions.

Dam operation or maintenance activities that could reduce the reservoir level will be coordinated with the Army Corp of Engineers to avoid the ECP upgrade window.

Likewise, operation and maintenance activities that could reduce the ability of the intake screens and fish nets to remove debris will also be schedule outside the ECP upgrade

0CAN022102 Enclosure Page 17 of 26 window. Periodic inspections will be performed on the screens and fish nets to detect degradation and allow repair before loss of function. These actions will be taken to minimize the challenges to the plant due to a potential loss of reservoir level.

The installation of the temporary ECP pumping system as described in Section 3.1 and the temporary pipe spool pieces to restore the ECP buried pipe, provides defense-in-depth.

This defense-in-depth measure is aimed at ensuring availability of the ECP as an UHS and maintaining the required flow to the SWS should an external flood occur. The current ECP design for delivering supply to the SWS pump bays is passive, except for the sluice gates. The temporary ECP pumping system is an active system. These differences were taken into account in the PRA and found to be a small increase to the overall plant risk.

These defense-in-depth measures have been established to prevent core damage, containment release, and to preserve consequence mitigation. The ability of the Entergy staff to respond to an emergency at ANO is not impacted by this change.

Preserve adequate capability of design features without an overreliance on programmatic activities as compensatory measures.

The proposed change will allow the ECP to remain Operable while upgrades are being performed on ECP supply piping to the SWS. The ECP is one of two systems that makeup the UHS. The preferred system normally used to satisfy the UHS requirements for ANO, the Dardanelle Reservoir, will remain available and aligned to the SWS. A temporary pumping system from the ECP to the SWS will be installed as a compensatory measure to mitigate a loss of lake event. The temporary system (discussed in Section 3.2) is designed to provide the necessary flow to the SWS as the current ECP pipe supplies to the SWS during shutdown and emergency operation. There will be programmatic activities (see Section 3.2) established to enhance the reliability of the reservoir and the temporary pumping system. The addition of the temporary pumping system, the pre-planned ability to re-close the ECP pipe, and the availability the Dardanelle Reservoir ensures that there is not an overreliance on the programmatic activities. Therefore, the proposed change preserves adequate capability of design features without an overreliance on programmatic activities as compensatory measures.

Preserve system redundancy, independence, and diversity commensurate with the expected frequency and consequences of challenges to the system, including consideration of uncertainty.

The UHS function is provided by either the Lake Dardanelle Reservoir or the ECP for redundancy. The capability of the temporary pumping system has been shown to provide the necessary flow to meet the design basis SWS flow requirements. The interaction of the temporary pumping system with the ECP does not degrade the ECP ability to remove decay heat or its ability to withstand external events. The pump piping and valves used by the temporary system remain independent from offsite and onsite power. The ability of the temporary pumping system to withstand the wind and seismic events has been shown through risk insights to be equivalent to the existing ECP delivery system for the 65-day duration of the planned upgrade activity. Since the temporary ECP spool pieces will provide the ability to supply flow to the SWS pumps during a flood, ECP functionality will be restored to support safe shutdown. Therefore, the temporary ECP pumping system and piping provides an acceptable means to remove decay heat from the SWS and maintains UHS redundancy.

0CAN022102 Enclosure Page 18 of 26 Independence between the two UHS sources will be maintained since operation and design of the existing Dardanelle Reservoir sluice gates that separate the two sources are not impacted by the temporary designs. The temporary ECP pumping system or piping spool pieces do not introduce any additional interactions between the two sources.

The method of cooling and the inventory quantity provided by the ECP will not change by use of the temporary ECP pumping system and piping, ensuring it remains diverse from the Dardanelle Reservoir.

The PRA analysis indicates that the proposed temporary ECP pumping system provides acceptable system redundancy, independence, and diversity commensurate with the expected frequency and consequences of challenges to the system, including consideration of uncertainty.

Preserve adequate defense against potential Common Cause Failures (CCFs).

Currently, there are no CCFs that could render both the Dardanelle Reservoir and the ECP incapable of supplying inventory to the SWS. As described in Section 2.1, both systems, the ECP and the Dardanelle Reservoir, feed the SWS pump bays separately.

The temporary pumping system that will be in place while the ECP supply piping is being upgraded, will also feed the SWS from the ECP and is also separate from the Dardanelle Reservoir. Therefore, the proposed change preserves adequate defense against potential CCFs.

Maintain multiple fission product barriers.

The proposed change does not impact the three fission barriers. The SWS bays will continue to be supplied by the preferred source, the Dardanelle Reservoir, and if the Dardanelle Reservoir is not available, the temporary ECP pumping system is capable of supplying the required inventory to the SWS bays to meet the design basis. The probabilistic evaluations found that the risk increase to the plant during the period of the ECP upgrade with the temporary ECP pumping system available are within the NRC risk increase criteria (CDF < 1 x 10-6 and LERF < 1 x 10-7). Therefore, the proposed change maintains the multiple fission product barriers.

Preserve sufficient defense against human errors.

Entergy will provide management oversight and support for emergent issues to ensure the impact on the UHS is thoroughly evaluated. Defense-in-depth measures include a trained person with communication from the control room available to start and monitor the temporary ECP pumping system. The 65-day ECP allowance is scheduled to end at the start of a spring refueling outage which provides a backstop that prevents extension of the 65-day allowance. The temporary pumping system will be pre-staged and tested prior to the start of the 65-day allowance. Temporary ECP piping spool pieces will be staged shortly after opening the ECP buried piping. Pre-job briefs will be conducted prior to and during the evolution to reinforce good human performance behaviors and other barriers that reduce risk. Other defense-in-depth measures will be established, as outlined in Section 3.1, providing additional barriers that are intended to minimize the potential for human errors. Therefore, the proposed change preserves sufficient defense against human errors.

0CAN022102 Enclosure Page 19 of 26 Continue to meet the intent of the plants design criteria.

The intent of the ANO-1 and ANO-2 design criteria with respect to this activity is to ensure an ultimate heat sink is available for at least 30 days to support normal, shutdown, and emergency operations. The temporary ECP pumping system is a compensatory measure which provides an alternate means of delivering ECP water to the SWS pump bays. The temporary equipment is intended to provide features that maintain the ECP's ability to fulfill its required design function when utilized as planned during piping upgrade period. Although the temporary equipment and piping material will not be designed or manufactured to nuclear quality standards, the temporary pumping system will be tested to nuclear quality standards as identified in the ANO-1 and ANO-2 SAR. A system hydrostatic and functional test will be performed prior to placing the temporary pumping equipment in service to ensure the pressure boundary material meets design pressure and the equipment performs as designed. In addition, periodic pump test and physical inspections on accessible portions of the system will be performed to detect any future material degradation or reliability concerns. These measures will provide equivalent quality methods that demonstrate reasonable assurance as to the materials and equipment ability to function as designed.

The temporary system pump, associated controls, fuel tank, and valve's seismic capability is substantiated through comparison to generic industry data. Based on the robustness of the temporary pumping system, the PRA found that the system provided sufficient capability to resist seismic events that have the potential to occur during the pipe upgrade window. A similar approach was taken with respect to wind resistance and tornado missile protection. While the system does not provide complete protection against high winds and tornado missiles, the PRA found that the wind capacity of the temporary ECP pumping system and the site features do provide sufficient protection against the potential wind events that could occur during the piping upgrade window. The external flooding event is not considered to occur coincident with any other events.

Additional details regarding compliance with the 10 CFR 50, Appendix A, GDC are provided in Section 4.1 of this enclosure.

3.5 Safety Margin An assessment of the principles from RG 1.177 and RG 1.174 have been evaluated to ensure sufficient safety margin is being maintained as a result of the proposed TS change.

The proposed change does not alter the assumptions or inputs in the accident analyses. The worst-case event with regard to the ECP is the loss of the Dardanelle Reservoir coincident with LOCA on ANO-2 with a normal shutdown of ANO-1 in progress. The temporary system and piping are sized to deliver the maximum design basis demand. The ECP maximum temperature, volume, flow requirements, and structural capability are not changed. Although the temporary equipment will not be manufactured under a 10 CFR 50, Appendix B, program, installation testing and inspections will demonstrate the functional and pressure capability of the equipment to meet design requirements which will provide reasonable assurance that the equipment is free of defects. While the physical protection of the temporary pumping system from wind and seismic events does not fully meet the SAR assumptions, enhanced capability to resist tornado and seismic events have been provided in the design of the temporary system.

0CAN022102 Enclosure Page 20 of 26 The PRA results for the 65-day piping upgrade indicate that the risk is within the NRC guidance for acceptable change. Therefore, this TS change will not significantly affect safety margin in that sufficient safety margin is maintained and the accident analyses acceptance criteria are met.

The evaluations in Sections 3.1 through 3.4 and in this section have concluded the proposed licensing amendment is consistent with the principle (from RG 1.174 and RG 1.177) that sufficient safety margins are maintained.

4.0 REGULATORY EVALUATION

4.1 Applicable Regulatory Requirements/Criteria ANO-1 was not licensed to the 10 CFR 50, Appendix A, GDC. ANO-1 was originally designed to comply with the 70 "Proposed General Design Criteria for Nuclear Power Plant Construction Permits," published in July 1967. However, the ANO-1 Safety Analysis Report (SAR) provides a comparison with the Atomic Energy Commission (AEC) GDC published as Appendix A to 10 CFR 50 in 1971.

In addition, ANO-2 was not licensed to the 10 CFR 50, Appendix A, GDC. ANO-2 was originally designed to comply with the 70 "Proposed General Design Criteria for Nuclear Power Plant Construction Permits," published in July 1967. However, like ANO-1, the ANO-2 SAR provides a comparison with the AEC GDC published as Appendix A to 10 CFR 50 in 1971.

GDC-5, Shared of Structures, Systems, and Components (SSCs)

GDC 5 for ANO-1 and ANO-2 requires SSCs important to safety shall not be shared between nuclear power units unless it is shown that their ability to perform their safety function will not be significantly impaired by the sharing.

The ECP serves as the source of emergency cooling water for simultaneously shutting down both ANO-1 and ANO-2 in the unlikely event of a loss of the Dardanelle Reservoir water inventory. The ECP is sized to contain sufficient water for dissipating the total combined heat transferred to the ANO-1 and ANO-2 SWSs during the design basis LOCA in one unit and a normal plant shutdown of the other unit, while limiting the cooling pond temperature to a maximum of 116 °F. The ECP is also sized to provide adequate fire protection water as part of the design basis. Separate suction and discharge water lines are used for supplying pond water to the ANO-1 and ANO-2 SWSs. The terminating ends of the lines at the cooling pond are housed in seismic Category 1 structures to prevent blockage of the pipe entrance and outlet.

GDC-44, Cooling Water GDC-44 for both ANO-1 and ANO-2 requires a system to transfer heat from SSCs important to safety to a UHS to be provided. The system safety function shall be to transfer the combined heat load of these SSCs under normal operating and accident conditions. The UHS is also required to have redundancy and be able to withstand a single failure.

0CAN022102 Enclosure Page 21 of 26 The ANO-1 and ANO-2 SSCs important to safety are cooled by the SWS. The SWS is redundant with two 100 percent capacity trains and three 100 percent capacity pumps which can be operated either from offsite power or from onsite emergency power. Two redundant sources of cooling water are available for reactor equipment to use as a UHS, the ECP and the Dardanelle Reservoir. These two sources feed the SWS separately and there is no single failure that could prohibit the UHS from meeting its design basis.

RG 1.174, "An Approach for using Probabilistic Risk Assessment in Risk-Informed Decisions on Plant-Specific Changes to the Licensing Basis" (Reference 6), and RG 1.177, "An Approach for Plant-Specific, Risk-Informed Decisionmaking: Technical Specifications" (Reference 7), are applicable to this amendment request. The NRC staff has defined an acceptable approach to analyzing and evaluating proposed TS changes. This approach supports the NRCs desire to base its decisions on the results of traditional engineering evaluations, supported by insights (derived from the use of PRA methods) about the risk significance of the proposed changes.

Decisions concerning proposed changes are expected to be reached in an integrated fashion, considering traditional engineering and risk information, and may be based on qualitative factors as well as quantitative analyses and information.

In implementing risk-informed decision making, TS changes are expected to meet a set of key principles. Some of these principles are written in terms typically used in traditional engineering decisions (e.g., defense-in-depth). Although written in these terms, it should be understood that risk analysis techniques can be, and are encouraged to be, used to help ensure and show that these principles are met. These principles include the following:

1. The proposed change meets current regulations unless it is explicitly related to a requested exemption or rule change.

2. The proposed change is consistent with defense-in-depth philosophy.

3. The proposed change maintains sufficient safety margins.

4. When proposed changes result in an increase in CDF or risk, the increases should be small and consistent with the Commissions Safety Goal Policy Statement.

5. The impact of the proposed change should be monitored using performance measurement strategies.

Each of these key safety principles are met as described in Sections 3.3 through 3.5 and .

RG 1.27, Revision 1, "Ultimate Heat Sink for Nuclear Power Plants" (Reference 1), is applicable to this amendment request. RG1.27, Revision 1, requires the UHS to perform two principal safety functions: (1) dissipation of residual heat after reactor shutdown and (2) dissipation of residual heat after an accident. In considering a multiple unit station, it is recognized that the design of each nuclear reactor unit includes sufficient safety in depth that it is highly unlikely that more than one reactor unit will be in an accident condition at any particular time. On this basis, the UHS complex serving multiple units should be capable of providing sufficient cooling water to permit simultaneous safe shutdown and cooldown of all units it serves and to maintain the units in a safe shutdown condition. Also, in the event of an accident in one unit, the UHS should be able to dissipate the heat for that accident safely, to permit concurrent safe shutdown and cooldown of the remaining units, and to maintain all of the units in a safe shutdown condition.

0CAN022102 Enclosure Page 22 of 26 The UHS complex, whether composed of single or multiple water sources, should be capable of withstanding, without loss of the sink safety functions, the following events:

The most severe natural phenomena expected taken individually, The site-related events (e.g. transportation accident, river diversion) that historically have occurred or that may occur during the plant lifetime.

Reasonably probable combination of less severe phenomena and/or site-related events.

A single failure of man-made structural features.

The UHS should consist of at least two sources, including the necessary retaining structures, each with the capability to perform the safety functions. While not discussed in RG 1.27, Revision 1, Operator action is allowed as discussed in RG 1.27, Revision 3, to switch from one UHS source to another.

The UHS sources for both ANO-1 and ANO-2 are the Dardanelle Reservoir and the ECP. While the Dardanelle Reservoir is the preferred source, the ECP is available in the unlikely event of the loss of the Dardanelle Reservoir. The design basis of the ANO UHS meets RG 1.27 by providing sufficient heat removal to shutdown one unit normally, shutdown both units normally, or shutdown of one unit normally with a simultaneous emergency shutdown of the other unit due to a LOCA.

Both the ECP and the Dardanelle Reservoir feed the SWS bays separately. There is no single failure that could prohibit the UHS from meeting its design basis as required by GDC 44 and Regulatory Guide 1.27.

The proposed change does not affect compliance with these regulations or guidance and will ensure that the lowest functional capabilities or performance levels of equipment required for safe operation are met.

4.2 Precedent The following precedent is associated with extended outages of safety related equipment and not necessarily associated with modification of a UHS supply pipe.

Brunswick - Control Room Emergency Ventilation System Instrumentation allowed to be considered Operable for a maximum of 63-Days during the upgrade of the control room air conditioning system (Reference 8)

Seabrook Day Allowed Outage Time (AOT) received for CR HVAC to replace chilled water piping (Reference 9)

Surry Day and 14-Day AOT received for CR and emergency switchgear room AC, and mechanical equipment room chilled water piping (Reference 10)

Susquehanna day AOT received for RHR, UHS and ESW to replace buried ESW piping over 4 refueling outages (Reference 11)

Callaway Day AOT received for essential SW to replace piping (Reference 12)

0CAN022102 Enclosure Page 23 of 26 Harris Day AOT received for Essential Chilled Water to perform maintenance (Reference 13)

Limerick- 7-Day AOT received for SFC, RHR, RHRSW, ESW, and EDG to replace RHRSW piping (Reference 14) 4.3 No Significant Hazards Consideration Analysis Entergy Operations, Inc. (Entergy) has evaluated the proposed changes to the Technical Specifications (TSs) using the criteria in 10 CFR 50.92 and has determined that the proposed changes do not involve a significant hazards consideration.

Entergy proposes a change to Arkansas Nuclear One, Unit 1 (ANO-1) TS 3.7.8, "Emergency Cooling Pond (ECP)," and ANO, Unit 2 (ANO-2) TS 3.7.4.1, "Emergency Cooling Pond," to allow the ECP to be considered operable on a one-time basis for up to 65 days during the proactive upgrade to the ECP supply piping, provided a loss of Lake Dardanelle event is not in progress and the Service Water System (SWS) is capable of being supplied from the ECP by a temporary pumping system should a loss of Lake Dardanelle occur. The proposed change permits the temporary pumping system to be unavailable for up to 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months , consistent with the TS allowance for an inoperable SWS loop, in order to perform testing or maintenance.

Basis for no significant hazards consideration determination: As required by 10 CFR 50.91(a),

the no significant hazards consideration is presented below:

1. Does the proposed change involve a significant increase in the probability or consequences of an accident previously evaluated?

Response: No The proposed change has been evaluated using the risk-informed processes described in Regulatory Guide (RG) 1.174, "An Approach for Using Probabilistic Risk Assessment in Risk-Informed Decisions on Plant-Specific Changes to the Licensing Basis," and RG 1.177, "An Approach for Plant-Specific, Risk-Informed Decision Making: Technical Specifications."

The risk associated with the proposed change was found to be acceptably small and, therefore, not a significant increase in the probability or consequences of an accident previously evaluated.

In addition, the proposed change does not affect the initiators of analyzed events or the assumed mitigation of accident or transient events. During the 65 days in which the ECP supply piping is being upgraded, cooling water to the SWS will continue to be supplied by the Dardanelle Reservoir, which is the preferred source during normal and emergency operation. The ultimate heat sink (UHS) and SWS will continue to perform the required functions during the 65-day period. If the temporary pumping system were to become unavailable for more than 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months or if a loss of Lake Dardanelle were to occur, the affected unit will be required to shutdown within 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months . Permitting the temporary pumping system to be removed from service for up to 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months is consistent with the time in which one of the two safety-related SWS loops may be inoperable in accordance with the TSs. In either case, safety functions are maintained by the availability of the Dardanelle Reservoir and the remaining operable SWS loop. As a result, accident probabilities and accident consequences are not affected by this proposed change.

0CAN022102 Enclosure Page 24 of 26 Therefore, this change does not involve a significant increase in the probability or consequences of an accident previously evaluated.

2. Does the proposed change create the possibility of a new or different kind of accident from any accident previously evaluated?

Response: No The proposed change does not involve a change in the UHS inventories relied upon to respond to plant transients. There is no alteration to the parameters within which the plant is normally operated or in the setpoints, which initiate protective or mitigative actions. The UHS and SWS will continue to perform the required safety functions since the Dardanelle Reservoir will remain available and a temporary pumping system will be capable of supplying the design basis ECP inventory to the SWS intake bays. Consequently, no new failure modes are introduced by the proposed change that would cause a new or different kind of accident.

Therefore, this change does not create the possibility of a new or different kind of accident from an accident previously evaluated.

3. Does the proposed change involve a significant reduction in a margin of safety?

Response: No Margin of safety is established through the design of the plant structures, systems, and components, the parameters within which the plant is operated, and the establishment of the setpoints for the actuation of equipment relied upon to respond to an accident or transient event. The proposed change does not prevent the UHS and SWS to perform the required safety functions. The preferred source of cooling water (Dardanelle Reservoir) to the SWS for normal and emergency conditions is expected to remain available. In addition, compensatory actions are also required to ensure the ECP inventory is available via a temporary pumping system or the buried pipe from the ECP to the SWS intake bays.

Furthermore, the proposed change has been evaluated using the risk-informed processes described in RG 1.174 and RG 1.177 and found that the risk associated with the proposed change was found to be acceptably small.

Therefore, this change does not involve a significant reduction in a margin of safety.

Based upon the reasoning presented above, Entergy concludes that the requested change involves no significant hazards consideration, as set forth in 10 CFR 50.92(c), Issuance of Amendment.

4.4 Conclusions In conclusion, based on the considerations discussed above, (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 Commissions regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.

0CAN022102 Enclosure Page 25 of 26

5.0 ENVIRONMENTAL CONSIDERATION

The proposed change would change a requirement with respect to installation or use of a facility component located within the restricted area, as defined in 10 CFR Part 20, and would change an inspection or surveillance requirement. However, the proposed change does not involve (i) a significant hazards consideration, (ii) a significant change in the types or significant increase in the amounts of any effluents that may be released offsite, or (iii) a significant increase in individual or cumulative occupational radiation exposure. Accordingly, the proposed change meets the eligibility criterion for categorical exclusion set forth in 10 CFR 51.22(c)(9).

Therefore, pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the proposed change.

6.0 REFERENCES

1. Regulatory Guide (RG) 1.27, "Ultimate Heat Sink for Nuclear Power Plants," Revision 1, (ML13038A084), March 1974.

2. U.S. Nuclear Regulatory Commission (NRC) NUREG-1430, Revision 4, "Standard Technical Specifications Babcock & Wilcox Plants," (ML12100A177), published April 2012.

3. NRC NUREG-1432, Revision 4, "Standard Technical Specifications Combustion Engineering Plants," (ML12102A165), published April 2012.

4. NRC NUREG-0212, Revision 0, "Standard Technical Specifications for Combustion Engineering Pressurized Water Reactors," (ML17266A003), dated March 15, 1977.

5. Entergy Operations, Inc. (Entergy) letter to NRC, "Proposed Alternative to ASME Boiler &

Pressure Vessel Code Section XI Requirements for Repair/Replacement of Emergency Cooling Pond (ECP) Supply Piping in accordance with 10 CFR 50.55a(z)(1)," Arkansas Nuclear One, Unit 1 and Unit 2, (0CAN072001) (ML20218A672), dated July 15, 2020.

6. RG 1.174, "An Approach for Using Probabilistic Risk Assessment in Risk-Informed Decisions on Plant-Specific Changes to the Licensing Basis," Revision 3, (ML17317A256),

January 2018.

7. RG 1.177, "An Approach for Plant-Specific, Risk-Informed Decisionmaking: Technical Specifications," Revision 1, (ML100910008), May 2011.

8. NRC letter to Carolina Power and Light Company, "Issuance of Amendment No. 191 to Facility Operating License No. DPR-71 and Amendment No. 222 to Facility Operating License No. DPR-62 Revising Technical Specifications Associated with the Control Room Emergency Ventilation System - Brunswick Steam Electric Plant, Units 1 and 2 (TAC Nos.

MA0112 and MA0113)," (ML020370049), dated February 6, 1998.

9. NRC letter to North Atlantic Energy Service Corporation, "Seabrook Station Unit No. 1 -

Issuance of Amendment Re: Control Room Air Conditioning Allowed Outage Time Extension (TAC No. MA5937)," (ML011920184), dated September 17, 1999.

0CAN022102 Enclosure Page 26 of 26

10. NRC letter to Virginia Electric and Power Company, "Surry Power Station, Unit Nos. 1 and 2, Issuance of Amendments Regarding Replacement of Main Control Room and Emergency Switchgear Room Air-Conditioning System Chilled Water Piping (TAC Nos.

MD4622 and MD4623)," (ML073480287), dated January 23, 2008.

11. NRC letter to Susquehanna Nuclear, LLC, "Susquehanna Steam Electric Station, Units 1 and 2 - Issuance of Amendment Nos. 275 and 257 Re: Temporary Changes to Allow Replacement of the Emergency Service Water System Piping (EPID L-2019-LLA-0004),"

(ML19248A844), dated January 17, 2020.

12. NRC letter to Union Electric Company, Callaway Plant, Unit 1 - Issuance of Amendment Re: One-Time Extension of Completion Time for Essential Service Water System Piping Replacement (TAC No. MD7252), (ML082810643), dated October 31, 2008.

13. NRC letter to Shearon Harris Nuclear Power Plant, "Shearon Harris Nuclear Power Plant, Unit 1 - Issuance of Amendment No. 176 Regarding the Extension of the Essential Services Chilled Water System Allowed Outage Time and Removal of an Expired Note from Technical Specifications (EPID L-2019-LLA- 0025)," (ML20050D371), dated March 31, 2020.

14. NRC letter to Exelon Nuclear, "Limerick Generating Station, Units 1 and 2 - Issuance of Amendments Re: Allowed Outage Time Extensions to Support Residual Heat Removal Service Water Maintenance (TAC Nos. ME3551 and ME3552)," (ML111960066), dated July 29, 2011.

ATTACHMENTS

1. Technical Specification Page Markups

2. Technical Specification Bases Page Markups

3. Retyped Technical Specification Pages

4. List of Regulatory Commitments

5. Probabilistic Risk Assessment

6. Temporary ECP Pump System Configurations

Enclosure, Attachment 1 0CAN022102 Technical Specification Page Markups (4 pages)

ECP 3.7.8 3.7 PLANT SYSTEMS 3.7.8 Emergency Cooling Pond (ECP)

LCO 3.7.8 The ECP shall be OPERABLE.

NOTE-------------------------------------------

The ECP may be considered OPERABLE on a one-time basis for up to 65 days during upgrade of the ECP supply piping to the SWS intake bays provided:

a. A loss of Lake Dardanelle event is not in progress, and

b. A temporary pumping system is capable of supplying the SWS from the ECP. The temporary pumping system may be unavailable for testing or necessary maintenance provided its availability is restored within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months .

APPLICABILITY: MODES 1, 2, 3, and 4.

ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. Degradation of the ECP A.1 Determine ECP remains 7 days noted pursuant to acceptable for continued SR 3.7.8.4 below or by operation.

other inspection.

B. Required Action and B.1 Be in MODE 3. 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months associated Completion Time of Condition A not AND met.

B.2 Be in MODE 5. 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months OR LCO not met for reasons other than Condition A.

ANO-1 3.7.8-1 Amendment No. 215,229,264,

ECP 3.7.8 SURVEILLANCE REQUIREMENTS Move to next page SURVEILLANCE FREQUENCY SR 3.7.8.1 Verify that the indicated water level of the ECP is In accordance with greater than or equal to that required for an ECP the Surveillance volume of 70 acre-ft. Frequency Control Program ANO-1 3.7.8-1 Amendment No. 215,229,264,

ECP 3.7.8 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY Moved from SR 3.7.8.1 Verify that the indicated water level of the ECP is In accordance with Page 3.7.8-1 greater than or equal to that required for an ECP the Surveillance volume of 70 acre-ft. Frequency Control Program SR 3.7.8.2 -------------------------------NOTE-----------------------------

Only required to be performed from June 1 through September 30.

Verify average water temperature is 100 °F. In accordance with the Surveillance Frequency Control Program SR 3.7.8.3 Perform soundings of the ECP to verify: In accordance with the Surveillance

1. A contained water volume of ECP Frequency Control 70 acre-feet, and Program

2. The minimum indicated water level needed to ensure a volume of 70 acre-feet is maintained.

SR 3.7.8.4 Perform visual inspection of the ECP to verify In accordance with conformance with design requirements. the Surveillance Frequency Control Program ANO-1 3.7.8-2 Amendment No. 215,229,264,

PLANT SYSTEMS 3/4.7.4 EMERGENCY COOLING POND LIMITING CONDITION FOR OPERATION 3.7.4.1 The emergency cooling pond (ECP) shall be OPERABLE1 with:

a. A minimum contained water volume of 70 acre-feet.

b. An average water temperature of 100 °F.

APPLICABILITY: MODES 1, 2, 3 and 4.

ACTION:

a. With the volume and/or temperature requirements of the above specification not satisfied or, with the requirements of Action b not met, be in at least HOT STANDBY within 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days 0.00833 hours 4.960317e-5 weeks 1.1415e-5 months .

b. If degradation is noted pursuant to 4.7.4.1.d below or by other inspection, perform an evaluation to determine that the ECP remains acceptable for continued operation within 7 days.

SURVEILLANCE REQUIREMENTS 4.7.4.1 The ECP shall be determined OPERABLE:

a. In accordance with the Surveillance Frequency Control Program by verifying that the indicated water level of the ECP is greater than or equal to that required for an ECP volume of 70 acre-feet.

b. In accordance with the Surveillance Frequency Control Program during the period of June 1 through September 30 by verifying that the pond's average water temperature at the point of discharge from the pond is within its limit.

c. In accordance with the Surveillance Frequency Control Program by making soundings of the pond and verifying:

1. A contained water volume of ECP 70 acre-feet, and

2. The minimum indicated water level needed to ensure a volume of 70 acre-feet is maintained.

d. In accordance with the Surveillance Frequency Control Program by performance of a visual inspection of the ECP to verify conformance with design requirements.

Note 1: The ECP may be considered OPERABLE on a one-time basis for up to 65 days during upgrade of the ECP supply piping to the SWS intake bays provided:

a. A loss of Lake Dardanelle event is not in progress, and

b. A temporary pumping system is capable of supplying the SWS from the ECP. The temporary pumping system may be unavailable for testing or necessary maintenance provided its availability is restored within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months .

ARKANSAS - UNIT 2 3/4 7-16 Amendment No. 153,271,315,

Enclosure, Attachment 2 0CAN022102 Technical Specification Bases Page Markups - Information Only (6 pages)

ECP B 3.7.8 LCO The ECP is a backup system that is required to be OPERABLE to support the SWS. To be considered OPERABLE, the ECP must contain a sufficient volume of water at or below the maximum temperature that would allow the SWS to operate for at least 30 days following the design basis event without exceeding the maximum design temperature of the equipment served by the SWS. To meet this condition, the ECP initial temperature should not exceed 100 °F, and the volume of water should not fall below 70 acre-feet during normal unit operation.

The LCO is modified by a Note which permits the ECP to be considered OPERABLE on a one-time basis for up to 65 days during upgrade of the ECP supply piping to the SWS intake bays provided:

a. A loss of Lake Dardanelle event is not in progress, and

b. A temporary pumping system is capable of supplying the SWS from the ECP. The temporary pumping system may be unavailable for testing or necessary maintenance provided its availability is restored within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months .

For the purposes of the proposed LCO Note, a loss of Lake Dardanelle is considered an event that renders the Dardanelle Reservoir unavailable for an extended period of time, likely with no known time for recovery. Such events include failure of the downstream Dardanelle Dam, notification from the Army Corps of Engineers of more than a momentary draw down of lake level below 335 ft mean sea level (MSL), a major oil or chemical spill which renders Lake Dardanelle unfit for use to support cooling of station equipment, or any other event that would result in more than temporary lowering of the intake canal below 335 ft MSL.

Other events that may require short duration use of the temporary pumping system such as clogging of SWS traveling screens are controlled by station procedures and are not considered a loss of Lake Dardanelle event with respect to this LCO Note.

Once the LCO Note is applied, the Note may be reapplied during startup should a unit shutdown occur during the 65-day period. If a unit shutdown occurred early in the 65-day maintenance window, the LCO would be exited upon entry into Mode 5; however, the LCO Note may be reapplied when entering Mode 4 from Mode 5, with the start of the 65-day allowable period being retroactive to the initial application of the LCO Note prior to the unit shutdown. For example, if a unit shutdown occurs 10 days following the commencement of the ECP piping upgrade and the unit remains in Mode 5 for 12 days, the proposed LCO Note may be reapplied upon entry into Mode 4 during plant restart; however, the time remaining in the original 65-day ECP piping upgrade window has now been reduced to 43 days (65 12 = 43).

The temporary pumping system is considered capable of supplying the SWS from the ECP provided it can be aligned to at least two SWS bays without delay during a loss of Lake Dardanelle event. Application of this LCO Note also requires the following compensatory and/or defense-in-depth measures to be maintained during the 65-day ECP supply piping upgrade.

Unforeseen circumstances which may invalidate one or more measures listed below are acceptable provided action is initiated immediately to restore the associated capability.

ANO-1 B 3.7.8-2 Amendment No. 215 Rev. 15,

ECP B 3.7.8 LCO (continued)

The temporary pump will be tested and minimum flow requirements verified prior to removing the installed ECP supply piping from service.

The Army Corps of Engineers will be briefed on the ECP piping upgrade activities and on the increased sensitivity of Lake Dardanelle level during the period of the ANO ECP piping upgrade. The Army Corps of Engineers will be requested to minimize any activity and provide advanced notification of activity that could impact the lake level or amount of debris in the lake.

The 65-day allowance for the ECP to remain operable during the ECP supply piping upgrade will be applied only prior to a spring outage to provide additional margin to the TS maximum ECP temperature limit.

The temporary pump system will be started to ensure its continued availability at least weekly.

Personnel trained to start the pump will be dedicated and onsite 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months a day, stationed in reasonable proximity of the pump, during the ECP piping upgrade when the ECP temporary pump is being relied upon as a backup for the Dardanelle Reservoir, with direct communications with the respective Control Room.

No elective maintenance or elective testing will be performed that could challenge the Dardanelle Reservoir SWS suction source.

The SWS pumps, bays, traveling screens, and sluice gates that are important for ensuring cooling water is provided to the supported SSCs will be given protected train status.

The intake traveling screens will be inspected for debris and general physical condition at least once per shift.

The accessible portions of the temporary ECP system piping will be inspected weekly.

Fish nets will be installed in the Dardanelle Reservoir SWS intake canal when required by existing winter operations procedural guidance and inspected for any gross physical damage or large quantities of debris twice a week, weather permitting, to ensure the nets remain intact and capable of performing the intended function.

An adequate fuel supply will be maintained to supply the temporary pump for approximately 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months of continuous operation.

At least once per week, a briefing will be conducted for applicable personnel to ensure individuals remain cognizant of the cues that would prompt operator action to start the temporary pumping system and open the discharge valve.

The ECP level will be maintained 5.5 ft during the 65-day preventative maintenance window.

The first three items above are performed prior to initial entry into the 65-day ECP piping upgrade window. Because unforeseen circumstances could arise that may temporarily prevent meeting one of the other ongoing commitments during the maintenance window, the LCO Note remains applicable (i.e., the ECP may be considered to remain operable) provided action is taken to restore the commitment without delay. This is considered reasonable since failure to meet one or more ongoing commitments does not immediately render the temporary ECP pumping system unavailable.

ANO-1 B 3.7.8-2 Amendment No. 215 Rev. 15,

ECP B 3.7.8 LCO (continued)

With the conditions associated with the LCO Note as defined above not met, the ECP may no longer be considered OPERABLE and Condition B becomes applicable.

APPLICABILITY In MODES 1, 2, 3, and 4, the ECP is a backup system that is required to support the OPERABILITY of the equipment serviced by the SWS and is required to be OPERABLE in these MODES.

In MODES 5 and 6, the OPERABILITY requirements of the ECP are determined by the systems it supports. Although the systems it supports may be required to be OPERABLE, the ECP is not required to meet the same OPERABILITY requirements in MODES 5 and 6 as it must in MODES 1, 2, 3, and 4. The definition of OPERABILITY embodies the principle that a system can perform its function(s) only if all necessary support systems are capable of performing their related support functions. If the supported system is capable of performing its safety function without reliance on the ECP, then the ECP is not required to be OPERABLE. Similarly, operation with the ECP in a less than fully qualified state is acceptable provided an assessment has been performed to determine that the supported system remains capable of performing its safety function. It is important to recognize that single failure criteria is not applicable in MODES 5 and 6. Therefore, the availability of Lake Dardanelle as a heat sink during periods of ECP unavailability may be acceptable provided the probability of a loss of lake and the time to respond to a loss of lake event are considered when planning ECP unavailability periods.

ACTIONS A.1 If degradation is noted during performance of SR 3.7.8.4 or during other inspection, the impact on ECP OPERABILITY must be assessed. As discussed in the SR 3.7.8.4 Bases below, an engineering evaluation is performed of any apparent changes in visual appearance or other abnormal degradation to determine OPERABILITY. The Completion Time associated with this action is reasonable based on the low probability that a loss of the Dardanelle Reservoir would occur in any 7-day period. If, by evaluation, the ECP is determined to be inoperable at any point during the 7-day evaluation period, the ECP must immediately be declared inoperable and Action B applied.

B.1 and B.2 If the ECP is inoperable, the unit must be placed in a MODE in which the LCO does not apply.

To achieve this status, the unit must be placed in at least MODE 3 within 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and in MODE 5 within 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months . The allowed Completion Times are reasonable, based on operating experience, to reach the required unit conditions from full power conditions in an orderly manner and without challenging unit systems.

ANO-1 B 3.7.8-2 Amendment No. 215 Rev. 15,

PLANT SYSTEMS BASES 3/4.7.4 EMERGENCY COOLING POND The limitations on the Eemergency Ccooling Ppond (ECP) volume and temperature are based on worst case initial conditions which could be present considering a simultaneous normal shutdown of Unit 1 and emergency shutdown of Unit 2 following a LOCA in Unit 2, using the ECP as a heat sink. The minimum indicated ECP level of 5.2 feet is based on soundings and includes measurement, calculation, and other uncertainties (equivalent to 0.15 feet) to ensure a minimum contained water volume of 70 acre-feet (equivalent to an indicated level of 5.05 feet),

crediting operator action to initiate makeup to the ECP upon a loss of Dardanelle Reservoir event as discussed below. These soundings ensure degradation is within acceptable limits such that the indicated level is consistent with the required volume and the pond meets its design basis. The measured ECP temperature at the discharge from the pond is considered a conservative average of total pond conditions since solar gain, wind speed, and thermal current effects throughout the pond will essentially be at equilibrium conditions under initial stagnant conditions. Visual inspections are performed to ensure erosion, undercut caused by wave action, or any physical degradation is within acceptable limits to enable the ECP to fulfill its safety function. An engineering evaluation shall be performed by a qualified engineer of any apparent changes in visual appearance or other abnormal degradation within 7 days to determine operability.

The limitations on minimum water level and maximum temperature are based on providing a 30-day cooling water supply to safety-related equipment without exceeding their design basis temperature and is consistent with the recommendations of Regulatory Guide 1.27, "Ultimate Heat Sink for Nuclear Plants," March 1974. Operator action is credited in the inventory analysis during the transfer of the Sservice Wwater Ssystem (SWS) to the pond. Specifically, pump returns are transferred to the pond shortly after a loss of lake event and pump suctions are transferred later in the event depending on pump bay level. In the time frame between the transfer of the returns and suctions to the pond, lake water is pumped into the pond, increasing level by at least 4.5 inches. This additional water is required, along with that maintained by Technical Specifications, to ensure a 66.9-inch pond depth, which ensures a 30-day supply of cooling water.

The LCO is modified by a Note which permits the ECP to be considered OPERABLE on a one-time basis for up to 65 days during upgrade of the ECP supply piping to the SWS intake bays provided:

a. A loss of Lake Dardanelle event is not in progress, and

b. A temporary pumping system is capable of supplying the SWS from the ECP. The temporary pumping system may be unavailable for testing or necessary maintenance provided its availability is restored within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months .

For the purposes of the proposed LCO Note, a loss of Lake Dardanelle is considered an event that renders the Dardanelle Reservoir unavailable for an extended period of time, likely with no known time for recovery. Such events include failure of the downstream Dardanelle Dam, notification from the Army Corps of Engineers of more than a momentary draw down of lake level below 335 ft mean sea level (MSL), a major oil or chemical spill which renders Lake Dardanelle unfit for use to support cooling of station equipment, or any other event that would result in more than temporary lowering of the intake canal below 335 ft MSL.

ARKANSAS - UNIT 2 B 3/4 7-5 Amendment No. 153 Revised by letter dated 9/8/95 Rev. 26,33,56,

3/4.7.4 EMERGENCY COOLING POND (continued)