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#REDIRECT [[LIC-14-0092, Response to NRC Request for Additional Information Regarding License Amendment Request (LAR) 13-03, Revising Method for Controlling Raw Water Intake Cell Level]]
| number = ML14226A738
| issue date = 08/13/2014
| title = Fort Calhoun, Unit 1 - Response to NRC Request for Additional Information Regarding License Amendment Request (LAR) 13-03, Revising Method for Controlling Raw Water Intake Cell Level
| author name = Cortopassi L P
| author affiliation = Omaha Public Power District
| addressee name =
| addressee affiliation = NRC/Document Control Desk, NRC/NRR
| docket = 05000285
| license number = DPR-040
| contact person =
| case reference number = LAR 13-03, LIC-14-0092
| document type = Letter
| page count = 14
}}
 
=Text=
{{#Wiki_filter:-n m iOmaha Public Power Distct444 South leh Street MallOmaha, NE 68102-2247LIC-14-0092August 13, 2014U.S. Nuclear Regulatory CommissionAttn: Document Control DeskWashington, DC 20555-0001Fort Calhoun Station, Unit No. 1Renewed Facility Operating License No. DPR-40NRC Docket No. 50-285
 
==Subject:==
OPPD Response to NRC Request for Additional Information Regarding LicenseAmendment Request (LAR) 13-03, Revising Method for Controlling Raw Water IntakeCell Level
 
==References:==
: 1. Letter from OPPD (L. P. Cortopassi) to NRC (Document Control Desk),"License Amendment Request (LAR) 13-03, Request to Revise UpdatedSafety Analysis Report to Allow Implementation of Modification EC 55394,Raw Water Pump Operation and Safety Classification of Components duringa Flood," dated August 16, 2013 (ML13231 A178) (LIC-13-0105)2. E-mails from NRC (J. Sebrosky / J. Rankin) to OPPD (B. Hansher), "FortCalhoun Request for Additional Information Associated with LicenseAmendment Request to Revise the Method for Controlling Raw Water IntakeCell Level During Floods (MF2591)," dated June 2, 5, 6, and 10, 2014(ML14156A222 (June 5th E-mail) / ML14162A376 (June 10th E-mail)) (NRC-14-0086)This letter responds to an NRC request for additional information (RAI) (Reference 2) regardingLicense Amendment Request (LAR) 13-03 (Reference 1), which proposed revisions to theUpdated Safety Analysis Report (USAR) to allow implementation of Modification EC 55394,"Raw Water Pump Operation and Safety Classification of Components During a Flood."The attachment contains OPPD's response to the NRC questions, which were received inseveral e-mails from the NRC.This letter contains no regulatory commitments.If you should have any questions regarding this submittal or require additional information,please contact Mr. Bill R. Hansher, Supervisor-Nuclear Licensing, at 402-533-6894.Employment with Equal Opportunity U. S. Nuclear Regulatory CommissionLIC-14-0092Page 2I declare under penalty of perjury that the foregoing is true and correct. Executed onAugust 13, 2014.R espectfully,Louis P. CortopassiSite Vice President and CNOLPC/CCS/mle
 
==Attachment:==
OPPD Response to NRC Request for Additional Information Regarding LicenseAmendment Request (LAR) 13-03, Revising Method for Controlling Raw WaterIntake Cell Level LIC-1 4-0092AttachmentPage 1OPPD Response to NRC Request for Additional InformationRegarding License Amendment Request (LAR) 13-03, RevisingMethod for Controlling Raw Water Intake Cell Level LIC-14-0092AttachmentPage 2By letter dated August 13, 2013 (Agencywide Documents Access and ManagementSystem (ADAMS) Accession No. ML13231A178) Omaha Public Power District (OPPD)submitted a license amendment application to revise the method for controlling rawwater intake cell level during floods. The U.S. NRC staff has reviewed the informationprovided in your August 13, 2013, license amendment request and determined thatadditional information is required in order to complete its review. These requests foradditional information (RAIs) can be found below. Please provide a response to theseRAIs by July 7, 2014. Should the NRC determine that the RAIs found below are no longernecessary prior to the dates found above, the request will be withdrawn. Ifcircumstances result in the need to revise the requested response date, please contactme or Jennie Rankin.REQUEST FOR ADDITIONAL INFORMATIONON LICENSE AMENDMENT FOR REVISING THE METHODFOR CONTROLLING RAW WATER INTAKE CELL LEVELFORT CALHOUN STATIONOMAHA PUBLIC POWER DISTRICTDOCKET NO. 50-285SBPB RAI 1The revised intake cell water level control method assumes that the travelling screensluice gates are fully closed. If a sluice gate cannot be closed, then the protection of theRaw Water (RW) pumps from flooding is not ensured by the proposed method forcontrolling the intake cell water level. Provide the following information regarding thesluice gates.a) How are the sluice gates verified closed in the event of a flood?b) Should a sluice gate fail to travel to the fully closed position, operators must beable to set it into place by other means. Describe the methods available to move asluice gate that fails to travel to the fully closed position.c) What steps are taken to ensure the sluice gates are maintained free ofobstructions (e.g., ice or debris)?d) Inadvertent opening of a sluice gate during a flood render the proposed methodfor controlling intake cell water level ineffective. What steps will be taken toprevent the inadvertent opening of a sluice gate during a flood?OPPD Responsea) A stem indicator is installed on each stem. The indicators were adjusted during postmaintenance testing (PMT), which utilized divers to verify full closure of each sluice gate.Operators manually ensure all "SLUICE GATE(S)", CW-14A/B/C/D/E/F are fully closedby verifying stem horizontal position marks are aligned (Intake Structure Veranda) asrequired by Abnormal Operating Procedure (AOP)-1, "Acts of Nature."b) Updated Safety Analysis Report (USAR), Section 2.7.1.2, "River Stage and Flow" showsthat it takes approximately two days before large flows reach Fort Calhoun Station, LIC-14-0092AttachmentPage 3which is sufficient time to prepare for the design basis flood. Standing Order (SO)-G-124 "Flood Barrier Impairment" is used in the event there is a degraded flood barrier. Inthis case, the degraded barrier (i.e., sluice gate) would be reviewed and actionsimplemented (e.g., flush seat, lower gate with rigging equipment, divers, etc.) to fullyshut the gate. The sluice gates and gate operators are maintained, inspected, andcycled to ensure that the sluice gates will fully close for a flooding event.c) The sluice gates are cycled on a frequency determined by the Preventive Maintenance(PM) program. The PM ensures that the sluice gates can be fully closed and are freefrom debris. In addition, the sluice gates are normally cycled weekly for trash rackbackwashing activities. Additionally, during walkdowns, Operations personnel visuallyensure that the stems are not bound by ice or other potential issues that could adverselyimpact functionality of the sluice gates. Finally, the sluice gates are operated in amanner that allows the seats of the sluice gates to be flushed prior to full closure.d) The sluice gates cannot be accessed during a flood. The sluice gate operators areinaccessible once the intake veranda is secured for flood protection using AOP-01 andPE-RR-AE-1001, "Flood Barrier and Sandbag Staging and Installation." In addition,AOP-01 requires the power to be removed from the sluice gate motor operators toprevent inadvertent opening of a sluice gate.SBPB RAI 2The revised intake cell water level control method must be established beforefloodwaters impact the RW pumps. In the event of a design basis flood, sufficient timemust be available to perform the operator actions associated with establishing therevised intake cell water level control method. Provide the following informationregarding the ability to perform operator actions within the available time.a) Are the actions to establish and verify the effectiveness of the revised intake cellwater level control method maintained in procedures?b) Following a plant shutdown in response to flood warnings or river level, howmuch time is available to establish the proposed intake cell water level controlmethod before the RW pumps are impacted by flood waters?c) Following a plant shutdown, how much time passes before the RW system coolingloads can be met by the flow provided using the revised intake cell water levelcontrol method? (i.e., with only one RW pump in operation, as described in theUpdated Final Safety Analysis Report (UFSAR) and License Amendment Request(LAR).d) Is the revised intake cell water level control method capable of supporting two RWpumps in operation?OPPD Responsea) AOP-01 contains steps for maintaining intake cell water level control prior to floodwatersimpacting the RW pumps. AOP-01 ensures that intake cell water level control isestablished prior to river level exceeding 1,004 feet MSL because all sluice gates mustbe closed at that level.
LIC-1 4-0092AttachmentPage 4b) As stated above, USAR Section 2.7.1.2, "River Stage and Flow" shows that it takesapproximately two days before large flows reach Fort Calhoun Station, which is sufficienttime to prepare for the design basis flood. The Shift Manager (SM) is responsible forshutting the plant down and implementing the required lineup prior to the river levelreaching 1,004 feet mean sea level (MSL). Additional considerations such as the rate ofriver rise also factor into the determination of AOP-01 entry. The current USAR Section2.7.1.2 described methodology requires five (5) of the six (6) sluice gates to be fullyclosed. Operations personnel then manipulate the remaining sluice gate nearly closed(i.e., -1" gap) to stabilize intake cell water level between 983 feet and 988 feet MSL.RW pump(s) are used to remove excess inflow. In contrast, the proposed method isless complex, more reliable, and quicker to implement because all six (6) sluice gatesare closed and the new flood control inlet valves are opened to stabilize intake cell waterlevel. RW pump operation is unchanged from the current methodology.c) The SM is responsible for initiating plant shutdown prior to the river reaching 1,004 feetMSL and aligning for single RW pump operation. As previously mentioned, the rate ofriver rise and the forecast are taken in account to allow for adequate lineups as requiredby station Technical Specifications and AOP-01. Thus, the time required to go onshutdown cooling varies but analysis shows that shutdown cooling can be achievedwithin 24 hours. This assumes reactor coolant system (RCS) temperature of 350°F (2hours after plant trip from full power), river temperature of 900F, component coolingwater (CCW) temperature as high as 1120F, and only one shutdown cooling heatexchanger (i.e., nominal fouling levels). An additional shutdown cooling heat exchangeris available to cool down at a faster rate. During hot weather (i.e., river temperature900F) in the summer, the typical time to cool down is from 12 to 24 hours and in thewinter, the time to cool down is approximately 3 hours.d) The revised method is designed for the operation of one (1) RW pump. However, two(2) RW pumps can be operated in nearly all situations but the operating duration of thesecond RW pump will depend on river level as well as sluice gate leakage. Forexample, two (2) RW pumps can run continuously during a 1,014 foot MSL flood, but foronly short durations when the river level is at 1,004 feet MSL. Per AOP-01, the stationmust have only one (1) RW pump in operation prior to establishing the new method ofcontrolling intake cell water level. A second RW pump can then be started to helpmaintain intake cell water level if necessary. The operation of one (1) RW pump is alsopreferred because it helps conserve fuel for the emergency diesel generators (EDG) inthe event that off site power is lost.SBPB RAI 3In order to maintain acceptable water level in the intake cells during a flood, the IntakeCell Flood Water Inlet Valves are operated manually to adjust inflow. Changes in the RWsystem flow rate and changes in the external flood elevation may require valveadjustments to adjust inflow. Therefore, operators should be available to take promptaction to control the intake cell water level. Provide the following information regardingthe capability of operators to control the intake cell water level.a) Will an operator be stationed at the valves for the duration of a flooding event?b) Indication of the intake cell water level is necessary for the operator to determinewhether valve adjustments were effective. Is there indication of the intake cell LIC-14-0092AttachmentPage 5water level visible to the operator adjusting the Intake Cell Flood Water InletValves? Describe how the indication provided is adequate to support theoperator's assignment.c) Is the operator protected from outside conditions while stationed at the intakestructure?OPPD Responsea) An operator is stationed in the intake structure during the entire flooding event and isdedicated to controlling intake cell water level per AOP-01.b) The operator will use the Distributed Control System (DCS) display for cell water levelindication. DCS screens are available in the intake structure and the control room. TheDCS screen in the intake structure is display only. The intake structure DCS display islocated just south of the new flood control inlet valves. In addition, the operator can getvisual indication from the north stairway or by removing a traveling screen panel. Thedigital DCS allows for reading twelve (12) different points for cell water level based onsix (6) traveling screens with a transmitter upstream and a transmitter downstream ofeach screen. During a flood, the water level in all three (3) circulating water cells isnearly identical in height because of the low flow. The six (6) traveling screentransmitters downstream of each screen alarm when water level reaches 979 feet MSL.In the event the DCS is lost, manual measurements can be performed per AOP-01.c) Yes, the operator is inside the intake structure and is protected from the outsideenvironment. Access to the intake structure is implemented by station flood mitigationprocedures with access gained by transiting over the truck dock flood barrier. The intakestructure is easily accessed because it is near the service building. The site layout isshown in USAR Figure 1.2-1 "Site Plan."SBPB RAI 4Potential failures or inadvertent actuation of equipment may require actions to correctthe intake cell water level by manipulating the Intake Cell Flood Water Inlet Valves.Sufficient time must be shown to be available for an operator to perform correctiveactions before the RW pumps are impacted by high or low water levels. For the followingscenarios, describe how much time is available to identify the problem and performcorrective actions:a) With water level being maintained at the minimum acceptable level allowed byprocedure, an additional RW pump is started.b) With water level being maintained at the minimum acceptable level allowed byprocedure, flow through one fully open Intake Cell Flood Water Inlet Valve ceases.c) With water level being maintained at the maximum acceptable level allowed byprocedure, one additional Intake Cell Flood Water Inlet Valves goes full open.
LIC-1 4-0092AttachmentPage 6OPPD ResponseNo analysis has been performed for the specific scenarios mentioned above. However, theassessment below demonstrates that operator error or valve failure does not pose an immediatethreat and that there is adequate time for an operator to recover. The total volume of the intakecells is very large (i.e., approximately 45,000 ft3 or 336,600 gallons). With only a nominal RWpump output of 5,325 gallons per minute (GPM), gradual increases (or decreases) in cell waterlevel would be detected by the dedicated operator and corrected prior to challenging the RWpumps. Changes in cell level from operator error (e.g., valve mispositioning) could also cause agradual increase or decrease in cell level.In maintaining cell water level between 983 feet to 988 feet MSL, gradual increases ordecreases in cell level would be detected with sufficient time to adjust the flood control valves.These cell levels are well within the range that the RW pumps are designed to operate, which isfrom 976 feet-9 inches to 1,007 feet-6 inches MSL. These level bands encompass the scenarioof a loss of a running EDG and allow sufficient time to manually start the standby EDG and anadditional RW pump to prevent intake cell water level from reaching 1,007 feet-6 inches MSL.The following hypothetical scenarios were evaluated to determine rate of cell rise and fall in theevent an operator severely mispositions a valve:* Intake cell starting level 983 feet MSL, zero sluice gate leakage, flood control valvesclosed, one (1) RW pump operation, river level 1,004 feet MSL. This scenario results ina cell water level decrease to 976 feet-9 inches MSL (i.e., RW pump minimumsubmergence level) in approximately 15 minutes." Intake cell starting level 983 feet MSL, 3,500 gpm sluice gate leakage, flood controlvalves closed, one (1) RW pump operation, river level 1,004 feet MSL. The scenarioresults in a cell water level decrease to 976 feet-9 inches MSL (i.e., RW pump minimumsubmergence level) in approximately 2 hours." Intake cell starting level 988 feet MSL, 3,500 gpm sluice gate leakage, 1 flood controlvalve open, one (1) RW pump operation, river level 1,014 feet MSL. The scenarioresults in a cell water level increase to 1,007 feet-6 inches (i.e., operating deck level) inapproximately 55 minutes.These hypothetical scenarios demonstrate that there is sufficient time for an operator to react inthe event that a valve is incorrectly positioned. Furthermore, it is unlikely that in an attempt tomaintain intake cell water level between 983 feet to 988 feet MSL, a trained and dedicatedoperator would make such extreme adjustments so as to cause a rapid rise or fall in cell level.In any case, the scenarios above demonstrate there is sufficient time to correct an error (e.g.,valve misposition).Finally, it should be noted that the current licensing basis for throttling flow using the sluicegates also allows cycling RW pump(s) on and off as needed to control intake cell water levelduring a flood. While the proposed method replaces the sluice gates as a means to controlflow, it does not change that aspect of RW pump operation.SBPB RAI 5The trash rack backwash piping must remain intact throughout a flooding event toensure the water level in the intake structure can be maintained. Fort Calhoun UFSARAppendix N requires components that "resist failure that could prevent any SC-1, -2, or -3 LIC-14-0092AttachmentPage 7equipment from performing its nuclear safety function" be classified as Non-NuclearSafety Class 1. Appendix N also states that the requirements for Non-Nuclear SafetyClass 1 equipment "are established on a case-by-case basis commensurate with thespecific NNS function performed."The LAR states that the trash rack backwash piping 'has been designed to withstandhydrostatic loads due to the flood event which are bounded by normal operation designloads." Describe the normal design loads of the trash rack backwash piping.OPPD ResponseThe piping is standard industrial process pipe (i.e., Schedule 40 ASTM A106 Gr. B with 150 lb.flanges). The maximum pressure and temperature that occurs in the trash rack backwashpiping during a design flood is 16.1 psi @ 900F, which the piping can easily withstand as it wasdesigned for a pressure and temperature of 50 psi @ 1500F.SBPB RAI 6The new intake cell flood water inlet valves are classified as Safety Class 3. Per USARAppendix N, Safety Class 3 corresponds to the USAS B31.7 Class III or ASME Section IIIClass 3 component design codes. The design conditions for Class 3 piping contained inthese codes include a requirement to consider the effects of seismic events.Additionally, USAR Appendix N states that Safety Class 1, 2, and 3 components areconsidered to be Seismic Category I. In Section 3.6, the LAR states that the intake cellflood water inlet valves are not required to be seismically qualified or seismicallysupported. Provide justification for the discrepancy between the code requirements andthe piping system with the intake cell flood water inlet valve design.OPPD ResponseA flood and a seismic event are not required to be postulated at the same time. Below 1,007feet-6 inches MSL, the intake structure is a Class I Structure designed to protect the safety-related RW system. This includes the operating floor above the RW pumps, the RW vault, andthe nosing of the intake structure in the river. The superstructure, which is that portion of theintake structure above 1,007 feet-6 inches MSL, is not a Class I structure and housesequipment that is not required to operate during a seismic event. Failure of the superstructureduring a seismic event will not cause the Class I substructure to fail, which ensures that the RWsystem is protected.USAR Section 9.8.6 shows the RW pumps are permanently protected against any water levelup to 1,007 feet-6 inches MSL by the Class I concrete substructure of the intake building.USAR Section 5.11.3 "Design Criteria -Class I Structures," a. "Loadings" shows that Class Istructures other than containment (e.g., the intake structure) were designed for an externalhydrostatic load from flooding up to elevation 1,014 feet MSL.Class I structures were also designed on the basis of no loss of function for load combinationsthat do not assume a flooding event concurrent with a seismic event:Flood (i.e., no seismic or tornado load):U = 1/ 0 (1.OD + 1.25H + 1.OF')
LIC-14-0092AttachmentPage 8Seismic (no flood)U = 1/ 4) (1.0D + 1.01L + 1.0E'); where live load is a considerationD = Dead loadE'= Seismic load from maximum hypothetical earthquakeF' = Hydrostatic load to elevation 1,014 feetH = Soil PressureL = Live loadBecause a seismic event is not postulated to occur simultaneous with a flooding event, the newflood control valves are not required to be seismically qualified or supported.PRA Operations and Human Factors Branch (APHB) RAI 1List and describe the procedure revisions required to support the LAR.OPPD ResponseEC 55394 will track implementation of the LAR and the following documents are listed asprocedures and other documents that will be revised during amendment implementation:Document Description of ChangeUSAR Section 2.7, Hydrology Modify description of how the intake cell waterlevel is maintained below 1,007 feet-6 inchesby closing the exterior sluice gates to severelyrestrict flow into the cells and then throttlingthe intake cell flood water inlet valves and/orvarying the raw water pump output to removethe inlet flow.This change includes removal of the alternateflow path during a flood due to the change inmethodology. Reference 01-CW-1 revisionbelow.USAR Section 9.8, Raw Water System Same as change to USAR Section 2.7.USAR Section 2.11, Section 2 References Will add reference to Amendment.STM-CW Volume 7, Circulating Water Same as change to USAR Section 2.7.SystemSTM-RW Volume 35, Raw Water System Same as change to USAR Section 2.7.
LIC-1 4-0092AttachmentPage 9AOP-01, Acts of NatureAOP-01 previously required all but one or twoof the sluice gates to be closed with throttlingdone by an open sluice gate to maintain cellwater level.AOP-01 was modified to instead maintainintake cell water level below 1,007 feet-6inches by closing all exterior sluice gates toseverely restrict flow into the cells and thenthrottling the intake cell flood water inlet valves(i.e., CW-323, -324, -325, & -326) and/orvarying the raw water pump output to removethe inlet flow.No change from current licensing basisregarding ability to start additional RWpump(s) to maintain cell level less than thedesign level of 1007 feet-6 inches MSL.01-CW-1 Attachment 18 is removed asdescribed under 01-CW-1 below.TBD-AOP-01, Acts of Nature Same as change to AOP-01.01-CW-1, Circulating Water System Normal Removes Attachment 18, "Sand IntrusionOperation Mitigation," which provided a method ofcontrolling intake cell water level by backflowfrom the discharge tunnel. This method wasdeveloped as a contingency if the partiallyopen sluice gate was blocked. However,because of the enhanced reliability of the newfloodwater inlet valves, Attachment 18 is nolonger needed.01-RW-1, Raw Water System Normal Removes mention of alternate flow path to theOperation intake structure of 01-CW-1, Attachment 18.SO-G-124, Flood Barrier Impairment References intake cell floodwater inlet valvesand removes Attachment 9, "Intake Cell LevelControl Components," and references to 01-CW-1, Attachment 18, "Sand IntrusionMitigation."New preventive maintenance (PM) procedure Inspects new flood control valves.for new valves (i.e., CW-323 through CW-326)New PM procedure for new stop valves (i.e., Inspects new flood control valves.CW-1 49 through CW-1 54)APHB RAI 2Describe the training that will be provided to support the LAR and the audience for thetraining.
LIC-14-0092AttachmentPage 10OPPD ResponseLicensed operators and non-licensed operators were given on shift training prior to theprocedures being issued. These procedures were issued to support the compensatorymeasures associated with the interim measures used for controlling intake cell water levelduring a flood. Lesson plans for Circulating Water for both non-licensed and licensed operatortraining programs and AOP-01 lecture for licensed operator training program will be updated forcontinuing training upon approval of this LAR.APHB RAI 3Describe the alarms, displays, and controls that operators will use to accomplish theproposed actions.OPPD ResponseDCS screens are available in the intake structure and the control room. The DCS screen in theintake structure is display only. In the event the DCS is lost, manual measurements can beperformed in accordance with AOP-01. An example DCS screen is shown below. The controlroom would receive the alarm, and open the alarm manager and take actions in accordancewith Annunciator Response Procedure ARP-DCS-TWS, "Traveling Water Screens DCSAnnunciator Response Procedure." River level alarms are as follows:High alarm: 999 feet MSLLow alarm: 982 feet MSLLow-low alarm: 980 feet MSLThe intake structure operator observes DCS cell water levels and manually adjusts any or all ofthe intake cell flood water inlet valves (i.e., CW-323, -324, -325, -326) to maintain the desiredcell level (i.e., 983 to 988 feet MSL). (During a flood, all three (3) intake cells are nearlyidentical in height because of the low flow.) If cell levels continue to rise, the operator isdirected to start additional RW pump(s) and stop them when cell levels reach 980 feet MSL.
LIC-14-0092AttachmentPage 11NýSMMS.-WDCS ScreenshotAPHB RAI 4Describe the method(s) that will be used to validate that the actions are feasible, reliable,and can be completed in the time available.OPPD ResponseThe current licensing bases requires installing flood gates, closing five (5) sluice gates andmaintaining one (1) sluice gate approximately one (1) inch open, the stationing of an operatorinside the intake structure to monitor intake cell levels. RW pump(s) are used to maintain intakecell levels. The only significant difference between the current method and the new method isthat the new method closes all six (6) sluice gates and then uses the new intake cell flood waterinlet and isolation valves to control intake cell level. Operation of the RW pump(s) is similar tothe current method.FCS demonstrated the ability to control intake cell levels for an extended period using thecurrent method during the 2011 Missouri River flood. A Notification of Unusual Event due tohigh river levels was declared on June 6, 2011 as described in Event Number 46929, which wasterminated on August 29, 2011. During that period, flood gates were installed, five (5) sluice LIC11 4-0092AttachmentPage 12gates were closed and one (1) throttled, and the current method of controlling intake cell levelswhile maintaining plant cooling functions was demonstrated.The use of manual control valves for controlling cell level is a significant improvement over thecurrent method. The operation of the manual control valves in this application has beendetermined to be well within an operator's capability. Engineering change (EC) 55394 containsthe analysis documenting the feasibility (i.e., the basis, valve sizing, etc.) of these actions. SO-G-74, "Fort Calhoun Station EOP/AOP Generation Program" was used to implement thechanges to AOP-01. SO-G-74 requires a verification and validation of the actions, whichincludes reviews, challenges, walkdowns, etc., of the proposed changes to ensure that theactions are feasible, reliable and can be completed in the available time.}}

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