LIC-13-0105, License Amendment Request (LAR) 13-03, Request to Revise Updated Safety Analysis Report to Allow Implementation of Modification EC 55394, Raw Water Pump Operation and Safety Classification of Components During a Flood

License Amendment Request (LAR) 13-03, Request to Revise Updated Safety Analysis Report to Allow Implementation of Modification EC 55394, Raw Water Pump Operation and Safety Classification of Components During a Flood

ML13231A178
Person / Time
Site:	Fort Calhoun
Issue date:	08/16/2013
From:	Cortopassi L Omaha Public Power District
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
LIC-13-0105, LAR 13-03
Download: ML13231A178 (32)

Text

444 South 16!1h Street Mall Omaha, NE 68102-2247 LIC-13-0105 August 16, 2013 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001

References:

1. Docket No. 50-285

2. Letter from NRC (J. A. Clark) to OPPD (D. J. Bannister), Fort Calhoun - NRC Integrated Inspection Report Number 05000285/2012002, dated May 11, 2012 (NRC-12-0049) (EA-2012-095) (ML12132A395)

3. Letter from OPPD (D. J. Bannister) to NRC (Document Control Desk), Response to NRC Inspection Report 05000285/2012002, EA-2012-095, dated June 11, 2012 (LIC-12-0080) (ML12164A431)

4. Letter from NRC (T. M. Blount) to OPPD (Lou Cortopassi), Denial of Violation in NRC Inspection Report 05000285/2012002, dated September 14, 2012 (NRC 0088) (EA-2012-095) (ML12258A293)

5. Letter from OPPD (Lou Cortopassi), Response to Denial of Violation in NRC Inspection Report 05000285/2012002, dated November 6, 2012 (LIC-12-0152)

(ML12312A109)

6. Letter from NRC (M. Hay) to OPPD (L. P. Cortopassi), Fort Calhoun - NRC Inspection Report 05000285/2013011 and Notice of Violation, dated March 11, 2013 (NRC-13-0029) (EA-13-043)

SUBJECT:

License Amendment Request (LAR) 13-03, Request to Revise Updated Safety Analysis Report to Allow Implementation of Modification EC 55394, Raw Water Pump Operationand Safety Classificationof Components during a Flood The Omaha Public Power District (OPPD) is submitting this license amendment request (LAR) to revise the design basis method for controlling the raw water (RW) intake cell level during periods of elevated river levels. Additionally, this amendment will resolve the violations of 10 CFR 50, Appendix B, Criterion Ill, Design Control, delineated in References 2 and 6, which identified that OPPD failed to properly classify the six (6) intake structure exterior sluice gates and their motor operators as Safety Class 3 (SC-

3) components as defined in the Updated Safety Analysis Report (USAR), Appendix N.

OPPD hereby requests an amendment to the Fort Calhoun Station (FCS), Unit No. 1, Renewed Facility Operating License No. DPR-40, to approve revisions to the current licensing basis (CLB) as described in the USAR to allow implementation of plant modification engineering change (EC) 55394, Raw Water Pump Operation and Safety Classification of Components during a Flood. Specifically, OPPD proposes to change the CLB described in the USAR Sections 2.7, Hydrology, and 9.8; Raw Water Systems, to provide the bases for the safety classification of components required for operation of the safety class 3 (SC-3) RW pumps. The modification EC 55394 would employ the trash rack blowdown portion of the circulating water system to allow river water to flow into four (4) of those pipes and then through four (4) newly installed safety class valves for control of cell level (RW pump suction level) using river level as the driving force. Implementing this strategy would eliminate the need for the exterior sluice gates to be safety class, thereby resolving the violation issued in Reference 2.

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U. S. Nuclear Regulatory Commission LIC-13-0105 Page 2 This LAR will therefore address the Nuclear Regulatory Commission (NRC) regional inspection and NRC Technical Specification (TS) Branch staff concerns regarding the current safety classification of components required for operation of the SC-3 RW pumps. The proposed change will ensure components required to protect the RW pumps are maintained and able to function for a flooding event.

The associated Basis for TS Limiting Condition for Operation (LCO) 2.16, River Level, is also being modified to reflect the function of the sluice gates during elevated river levels due to a flood. These TS Bases Changes (TSBCs) are included for information and will be processed in accordance with TS 5.20, TS Bases Control Program.

OPPD concludes that the proposed LAR presents no significant hazards consideration under the standards set forth in 10 CFR 50.92(c). Pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment needs to be prepared in connection with the issuance of this amendment.

The enclosure contains OPPD's evaluation of the proposed changes, including the supporting technical evaluation, and the significant hazards consideration determination. Attachment 1 of the enclosure provides the existing Updated Safety Analysis Report (USAR), marked-up to show the proposed changes. Attachment 2 of the enclosure provides the retyped (clean) version of the affected USAR sections. Attachment 3 provides the existing TS Bases pages marked-up to show the proposed changes to TS 2.16 Basis. Attachment 4 provides the associated retyped (clean) TS Bases pages. Attachment 5 provides the figure depicting the intake flood cell level control for modification engineering change (EC) 55394.

OPPD requests approval of the proposed amendment by August 16, 2014. Once approved, the amendment shall be implemented within 120 days.

There are no regulatory commitments associated with this proposed change.

In accordance with 10 CFR 50.91, a copy of this application, with attachments, is being provided to the designated State of Nebraska official.

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.

I declare under pe y of pe jury that the foregoing is true and correct. Executed on August 16, 2013.

Louis P. Cortopassi Site Vice President and CNO

Enclosure:

OPPD's Evaluation of the Proposed Change(s) c: S. A. Reynolds, Acting NRC Regional Administrator, Region IV J. M. Sebrosky, NRC Senior Project Manager L. E. Wilkins, NRC Project Manager J. C. Kirkland, NRC Senior Resident Inspector Manager Radiation Control Program, Nebraska Health & Human Services, R & L Public Health Assurance, State of Nebraska

LIC-13-0105 Enclosure Page 1 OPPD's Evaluation of the Proposed Change(s)

License Amendment Request (LAR) 13-03, Request to Revise Updated Safety Analysis Report to Allow Implementation of Modification EC 55394, Raw Water Pump Operationand Safety Classificationof Components during a Flood 1.0

SUMMARY

DESCRIPTION 2.0 DETAILED DESCRIPTION

4.0 REGULATORY EVALUATION

4.1 Applicable Regulatory Requirements/Criteria 4.2 Precedent 4.3 Significant Hazards Consideration 4.4 Conclusions

6.0 REFERENCES

ATTACHMENTS:

1. Updated Safety Analysis Pages [Mark-up Pages]

2. Updated Safety Analysis Pages [Retyped ("Clean") Pages]

3. Technical Specification Bases Information Only Page - Markups

4. Retyped ("Clean") Technical Specifications Bases Information Only Page

5. Figure 1 - Intake Flood Cell Level Control for EC 55394

LIC-13-0105 Enclosure Page 2 1.0

SUMMARY

DESCRIPTION The Omaha Public Power District (OPPD) hereby requests an amendment to the Fort Calhoun Station (FCS), Unit No. 1, Renewed Facility Operating License No. DPR-40, to approve revisions to the current licensing basis (CLB) as described in the Updated Safety Analysis Report (USAR) to allow implementation of plant modification engineering change (EC) 55394, Raw Water Pump Operation and Safety Classification of Components during a Flood.

Specifically, OPPD proposes to change the CLB described in the USAR Sections 2.7, Hydrology, and 9.8, Raw Water Systems, to provide the basis for the safety classification of components required for operation of the Safety Class 3 (SC-3) raw water (RW) pumps.

This license amendment request (LAR) will address Nuclear Regulatory Commission (NRC) regional inspection and NRC Technical Specifications (TS) Branch staff concerns regarding the current safety classification of components required for operation of the SC-3 RW pumps.

The proposed change will ensure components required to protect the RW pumps are maintained and able to function for a flooding event.

The associated TS Bases for TS Limiting Conditions for Operation (LCO) 2.16, River Level, which are provided for information purposes, are also being revised in accordance with TS 5.20, TS Bases Control Program.

2.0 DETAILED DESCRIPTION The proposed changes for LAR 13-03 are as follows:

Modification Engineering Change (EC) 55394 (Reference 6.12)

The external flooding 95002 preparation team identified that the quality classification for the intake structure cell level control equipment may be incorrect. This issue was discussed during an NRC inspection conducted from November 18, 2012, to February 28, 2013, and a violation of NRC requirements was identified. (Reference 6.16) The violation is restated below:

Title 10 CFR 50, Appendix B, Criterion Ill, "Design Control," requires,in part that measures shall be established to assure that applicable regulatory requirements and the design basis, as defined in 10 CFR 50.2, for those structures, systems, and components are correctly translatedinto specifications, drawings, procedures,and instructions. Contraryto the above, the licensee failed to establish measures to assure that applicable regulatory requirements and the design basis for those components were correctly translated into specifications, drawings, procedures, and instructions. Specifically, the licensee failed to classify the six intake structure exterior sluice gates and their motor operators as Safety Class 3 as defined in the Updated Safety Analysis Report, Appendix N.

The original licensing basis utilized the sluice gates to severely restrict water during a flooding event and then varying the RW pump output to remove the inlet flow. This strategy is implemented under abnormal operating procedure, AOP-01, Acts of Nature, which involves closing five (5) of the six (6) exterior sluice gates and positioning the remaining gate such that a balance between inflow and RW pump discharge is achieved prior to river water level rising to 1004 feet mean sea level (msl). This method of cell level control and use of non-nuclear safety class sluice gates has been called in to question by the NRC. This LAR eliminates the need to regulate flow into the circulating and RW cells using the sluice gates.

LIC-13-0105 Enclosure Page 3 OPPD hereby requests approval to allow implementation of modification EC 55394, Raw Water Pump Operation and Safety Classificationof Components during a Flood, which closes six (6) riverside traveling screen sluice gates and utilizes four (4) new SC-3 butterfly valves off four (4) Limited CQE (augmented quality) trash rack backwash lines that supply water to the RW pumps during a flood. The butterfly valves are manually controlled and minimize the impact of cycling a second RW pump for controlling cell level. (See Enclosure, Attachment 5 -

Figure 1)

USAR Changes The changes to USAR Section 2.7.1.2 and USAR Section 9.8.6 for which NRC approval is sought are found in Attachments 1 and 2. Attachment 1 contains the markup of these sections showing new text in double underline and deleted text in strikeout. Attachment 2 contains the revised (i.e., clean) pages showing the text with revision bars in the right margin denoting where changes were made.

USAR Section 2.7, Site and Environs, Hydrology The proposed changes to USAR Section 2.7.1.2, River Stage and Flow, to incorporate the modification are as follows:

Flooding protection against the 1,009.3 foot flood in the intake structure is provided by removable flood barriers which extend to at least 1014 feet and intake cell level control maintained by the raw water pumps. When required, these flood barriers are installed in all exterior openings on the operating level of the intake structure. In addition, a flood barrier is installed at the outlet of the screen wash discharge trough at the south end of the traveling screens. The intake cell level will be maintained below 1,007.5 feet by ajoustii*g

~j~pgthe exterior sluice gates to severely restrict flow into the cells and the,, and throttling the intake cell flood water inlet valves and/or varying the raw water pump output to remove the inlet flow. (Reference 39)

The proposed USAR 2.7.1.2 changes implement the use of the intake cell flood water inlet valves installed via modification EC 55394. The amendment will be added to the USAR Section 2 References as Reference 39 (or the next available number in the reference sequence) during implementation.

USAR Section 9.8, Auxiliary Systems, Raw Water Systems The proposed changes to USAR Section 9.8.6, to incorporate the modification, are as follows:

Protection for the raw water pumps and their drives against floods is provided at three elevations as indicated on Figure 9.8-1. The pumps are permanently protected against any water level up to elevation 1,007.5 feet by the Class I concrete substructure of the intake building. See Section 2.7 for additional information. Protection against the 1,009.3 foot and 1,014 foot floods (discussed below) is provided by gasketed steel closures at exterior doorway openings and the screen wash discharge trough. The water level inside the intake cells can be controlled by pre positionin I9-2 the exterior sluice gates (i.e., befoFe floodwater reaches the elevation that prevents access to the 8sluice gate actuators) toem-sev=Ly rest-rit the infRlw i*nt* the -ells. intake cell level is then controlled by and throttling the intake cell flood water inlet valves and/or varying the raw water pump output to remove the inlet flow.

LIC-13-0105 Enclosure Page 4 if the cel! intake througjh the riVer Sluice gates is,blocked during flooding condition (possibly due to debris or other failre mne*hanism) an alterate flow path to the cells can be provided by allo)wing flow backward through one of the circulating pumps. Cell level would then be controlled using either the cirulating water pump flooding conditions if the river flow has a high debris load to minimize sand/debris buildup iR the cells. (The plant must be shutdo', with the circulatffing watr system The proposed USAR Section 9.8.6 changes implement the use of the intake cell flood water inlet valves installed via modification EC 55394 (Reference 6.12).

Technical Specification Basis Changqe (TSBC) - For Information Purposes The associated TSBCs for TS LCO 2.16 proposed by this LAR are to provide clarification for the use of the intake cell flood water inlet valves for controlling intake cell water level. The proposed TSBCs are provided for information purposes and will be processed in accordance with TS 5.20 as part of the amendment implementation.

TS 2.16 Basis (Mark-up):

The intake structure can be protected from these Missouri River floods using removable flood gates on doorways and the screen wash discharge trough. The water level inside the intake cells can be controlled by position*lg' the exterior sluice gates to restFiGt the flow into the cells and throttling the intake cell flood water inlet valves and/or varying the raw water pump output to remove the inlet flow.

3.0 TECHNICAL EVALUATION

Fort Calhoun Station (FCS) is designed to provide flood protection for safety related structures up to the license basis flood level of 1,014 feet msl. The current method for providing protection of the intake structure is accomplished by installation of removable flood barriers which extend to at least 1014 feet and intake cell level control maintained by adjusting exterior sluice gates to severely restrict flow and then varying the RW pump output to remove inlet flow. (References 6.5 and 6.7, USAR Sections 2.7.1.2 and 9.8.6) 3.1 Design Basis Flood - Defined The design basis flood is defined for FCS in USAR Section 2.7, Site and Environs, Hydrology, (Reference 6.5).

The requirement to protect the plant from flooding conditions is provided in the 70 Draft Design Criteria (GDC), Criterion 2 as stated in the FCS USAR Appendix G (Reference 6.2)

Those systems and components of reactorfacilities which are essential to the prevention of accidents which could affect public health and safety or to mitigation of their consequences shall be designed, fabricated, and erected to performance standards that will enable the facility to withstand, without loss of the capability to protect the public, the additional forces that might be imposed by natural phenomena such as earthquakes, tornadoes, flooding conditions, winds, ice and other local site effects. The design bases so established shall reflect: (a) appropriateconsiderationfor the most severe of these natural phenomena that have been recorded for the site and the surrounding area and (b) an appropriate margin for withstanding forces greater than those recorded to reflect uncertaintiesabout the historicaldata and their suitability as a basis for design.

LIC-13-0105 Enclosure Page 5 3.2 System Descriptions Raw Water and Component Cooling Water (CCW) Systems:

Heat removed by the CCW system is transferred to the RW system by the CCW heat exchangers. The RW system is a once through system operating with screened river water.

Redundancy has been provided in the CCW and RW systems to provide for both normal and emergency operation with pumping and heat exchange equipment out of service. Further, the system arrangement permits the raw water to be circulated through portions of the CCW system piping to provide direct cooling of vital engineered safeguards components in the unlikely event of all of the CCW pumps and heat exchangers being unavailable to fulfill their design function. (Reference 6.4, Section 1.2.8.3)

Four RW pumps are installed in the intake structure pump house to provide screened river water to the CCW heat exchangers. The pump discharge piping is arranged as two headers which are interconnected and valved at the pumps and in the auxiliary building. Each header was designed to accommodate sufficient flow to the CCW heat exchangers to support normal modes of plant operation. System pressures, flows and valve positions are displayed in the control room. Water level instrumentation in the intake structure will alarm in the control room if water from any source should endanger the RW pumps. A majority of the system operational and control functions can be performed from the control room. (Reference 6.7, Section 9.8.2) 3.3 System Classification Classification of Equipment The external flooding 95002 preparation team identified that the quality classification for the intake structure cell level control equipment may be incorrect (condition report (CR) 2011-10302). This issue was also raised in NRC Integrated Inspection Report Number 05000285/2012002 dated May 11, 2012. (Reference 6.9) The proposed change will address the quality classification of the components that supply and control the flow of river water to the RW pumps during flood conditions while the plant is operating under abnormal operating procedure AOP-01, Acts of Nature, and will provide a flow path for water from the river to the RW pumps under flood conditions that will eliminate the need to regulate flow into the circulating water (CW) cells using the sluice gates.

Critical Quality Elements (CQE) are defined as those structures, systems, components, or items whose satisfactory performance is required to prevent or mitigate the consequences of postulated accidents that could cause undue risk to the health and safety of the public.

Safety Class 3 (SC-3) shall apply to equipment, not included in SC-1 or -2, that is designed and relied upon to accomplish the following nuclear safety functions:

• Ensure nuclear safety functions provided by SC-1, -2, or -3 equipment (e.g., provide heat removal of SC-1, -2, or -3 heat exchangers, provide lubrication of SC-2 or -3 pumps, or provide fuel oil to the emergency diesel engine). (Reference 6.10, USAR Appendix N)

Limited Critical Quality Elements (Limited CQE) are defined as those structures, systems, components or items whose satisfactory performance is required to prevent or mitigate the failure of those structures, systems, components or items identified as CQE.

LIC-13-0105 Enclosure Page 6 Non-Critical Quality Elements (Non-CQE) are defined as those structures, systems, components or items that have no special performance or quality requirements as defined for CQE, Limited CQE or Non-CQE with special requirements.

Flood protection barriers are required in the intake structure to protect safety related equipment from the design basis flood. The flood protection barriers must provide an adequate seal for these opening and resist structural failure from the required hydrostatic loading. The flood protection barriers function to protect safety related equipment; therefore, they are classified as Limited CQE. (Reference 6.11, CQE List)

Critical Quality Elements (CQE)

Intake Cell Flood Water Inlet Valves The new intake cell flood water inlet valves, CW-323, CW-324, CW-325 and CW-326, installed under modification EC 55394 are classified as SC-3. The ability to open and throttle these valves is required to establish a flow path of river water to the RW pumps when the traveling screen sluice gates are closed and the piping leading to the valves is intact.

Limited Critical Quality Elements (Limited CQE)

Traveling Screen and Circulating Water Sluice Gates As part of the implementation of modification EC 55394, the six (6) traveling screen sluice gates, CW-14AIB/C/D/E/F, and the three (3) CW pump sluice gates, CW-15A/B/C will all be procedurally closed under flooding conditions via AOP-01, Acts of Nature,Section I, Flood (Reference 6.3). The sluice gates will no longer be in the flow path for river water to the RW pumps under these conditions. The six (6) traveling screen sluice gates CW-14A through F provide a passive function during a flooding event. They are designed to severely restrict water from the river side during a flooding event. The normal position for the gates during operation is in the open condition. Since manual operation of the sluice gates is credited under flooding conditions, the components required for manual operation are also Limited CQE. This includes the operators associated with each of the gates (CW-14A-O to CW-14F-0).

The circulating water sluice gates CW-15A/B/C provide a passive function during a flooding event. They are designed to severely restrict water from the CW pump inlet tunnel during a flooding event. The normal position for the gates during operation is in the open condition.

Since manual operation of the sluice gates is credited under flooding conditions, the components required for manual closure are also Limited CQE. This includes the operators associated with each of the gates (CW-15A-0 to CW-15C-O). The gates are redundantly backed up by non-safety CW pump discharge check valves FCV-1904A/B/C and CW pump discharge valves HCV-1905A/B/C which are closed once the CW pumps are secured. These three barriers are designed to restrict the back flow of water during normal and flooding conditions.

18-inch Piping and Stop Valves The 18-inch trash rack backwash piping from and including valves, CW-149, CW-150, CW-151, CW-152, CW-153 and CW-154, trash rack grid backwash stop valves, downstream to where the trash rack backwash lines exit the intake structure are flood barriers for the intake structure and therefore, are classified as Limited CQE.

LIC-13-0105 Enclosure Page 7 Intake Cell Flood Water Isolation Valves Intake cell flood water isolation valves, CW-327, CW-328, CW-329 and CW-330, are only used upon a failure of an intake cell flood water inlet valve during an AOP-01 flood event. The isolation valves would be closed and function as a flood barrier if an active failure of the inlet valve was to occur. These valves and the components required for manual closure of the valves are classified as Limited CQE.

Non-Critical Quality Elements (Non-CQE)

Traveling Screen and Circulating Water Sluice Gate OperatorMotors The operator motors for the sluice gates are Non-CQE. The motors, limit and torque switches, and operating push buttons are not credited for operation for a flooding event. The motors can be used to close the gates; however, full closure is credited by manual gate control.

Following a flooding event, the river level decreases to the point where there is insufficient flow through the backwash supply header and the exterior sluice gates will need to be reopened.

However, the motors for the exterior sluice gates could be damaged which could impair the ability to reopen the sluice gates and establish sufficient flow to the intake bays. Therefore, AOP-01 directs, upon receding river level, to manually open one sluice gate prior to insufficient flow conditions.

Trash Grids The trash grids upstream of the traveling screen sluice gates are Non-CQE. These grids perform a passive function by preventing large objects from entering the intake cells. Since the CW pumps are not in operation during a flood, the flow through the trash grids is reduced and therefore the flow path will not be impeded by debris.

Traveling Screens The traveling screens downstream of the traveling screen sluice gates are Non-CQE. These screens are not in operation during a flood and perform a passive function by preventing debris from entering the intake cells. Since the CW pumps are not in operation during a flood, the flow through the traveling screens is reduced and therefore the flow path will not be impeded by debris. In addition, the flow path through the trash rack backwash piping is such that water is taken from 5 feet above the bottom of the river which is at minimum 25 feet below the surface of the river during the AOP-01 entry condition of 1,000 feet. This flow path minimizes the impact of silt and river debris from entering the cells.

3.4 Functional Requirements Under flood conditions, the grid backwash piping will be isolated from the usual circulating water intake tunnel water source using the trash rack grid backwash stop valves, CW-149 through CW-154. The sluice gates are isolated and function as a flood barrier. The intake cell flood water inlet valves are then throttled open to allow river water to back flow through the grid backwash piping into the circulating water cells to supply the RW pump(s) during flood conditions while operating under AOP-01. The intake cell flood water inlet valves, CW-323, CW-324, CW-325 and CW-326, and the intake cell flood water isolation valves, CW-327, CW-328, CW-329 and CW-330, are located at elevation 998' 10" accessible just above the walkway grating level between the east wall of the intake structure and the traveling screens.

The valves are equipped with long stem manual operators. This allows the valves to be operated from the main operating floor, elevation 1007' 6", of the intake structure.

LIC-13-0105 Enclosure Page 8 The piping and intake cell flood water inlet valves off the trash rack backwash lines have been sized to provide sufficient flow capacity to supply one RW pump with river water during flood conditions after the traveling screen sluice gates are closed under AOP-01. The number of intake cell flood water inlet valves needed to match the flow output of one RW pump is dependent upon the river level and presence of inleakage (if any). In the event an intake cell flood water inlet valve fails open, an intake cell flood water isolation valve or second RW pump is available to restrict or remove excess water to maintain intake cell level.

The non-safety traveling screens are de-energized under AOP-01 and are not required for RW pump operation. Since the CW pumps are not in operation during a flood, the flow through the traveling screens is reduced and therefore the flow path will not be impeded by debris.

The non-safety trash grids are unable to be cleaned during a flood due to CW pumps being isolated per AOP-1 and the trash grid backwash pipe lines are reversed in flow for supplying water to the intake cells during a flood. Since the CW pumps are not in operation during a flood, the flow through the trash grids is reduced and therefore the flow path will not be impeded by debris.

In addition, the flow path through the trash rack backwash piping is such that water is taken from 5 feet above the bottom of the river which is at minimum 25 feet below the surface of the river during the AOP-01 entry condition of 1,000 feet. This flow path minimizes the impact of silt and river debris from entering the cells.

3.5 Preventive Maintenance (PM) Activities To ensure the function of the intake structure flood barriers, the following PM activities and planned recommended frequencies are implemented with EC 55394 (exact frequencies to be determined via the FCS PM Program):

• Determine In-Leakage through the Sluice Gates

" Perform Visual Inspection of Intake Structure Sluice Gates

• Cycle and Inspect Intake Cell Flood Water Inlet Valves

• Cycle and Inspect Intake Cell Flood Water Isolation Valves

• Inspect Trash Rack Grid Backwash Stop Valves

• Inspect Traveling Screen Sluice Gate Visual Level Indicators

• CW-14A/BIC/D/E/F Cycle Sluice Gates through Full Range

• CW-15A/B/C Cycle Sluice Gates through Full Range

" Clean and Inspect CW-14A/B/C/D/E/F Sluice Gates

" Clean and Inspect CW-15A/B/C Sluice Gates The sluice gate operators are inspected and/or overhauled via the existing PM tasks.

LIC-13-0105 Enclosure Page 9 3.6 Seismic The intake cell flood water inlet valves installed under modification EC 55394 are not required to be seismically qualified or seismically supported. This applies also to the portion of the trash rack backwash lines that are classified as Limited CQE, the traveling screen and CW pump sluice gates, and all flood barriers. These components are not credited for any other nuclear safety function. USAR Section 5.11, Structures Other Than Containment; EA1 0-032, External Flooding Design Basis; and calculation FC07808, Intake Structure Substructure Analysis, (References 6.6, 6.1, and 6.14, respectively), specify that hydrostatic flood loads and seismic loads are not considered concurrently on USAR Appendix F, Class I structures (Reference 6.13).

This is consistent with other Design Basis Events which do not require multiple concurrent events or accidents to be analyzed. In addition, this is consistent with CQE List, Part One, Attachment V, ANSI/ANS 51.1-1983, Table 3-5, Basic Requirements for Equipment by Safety Class, Note 9, which states that some design approaches may allow exceptions to be taken for seismic requirements. (Reference 6.15) 3.7 Safety Class Interface USAR, Appendix N (Reference 6.10) provides the following requirements for safety class interface:

"If failure of Safety Class or NNS equipment connected to other Safety Class equipment could prevent the latter equipment from accomplishing its nuclear safety function, an interface barrieror isolation device shall be provided to protect the latter equipment." (Reference 6.10, Section 3.0)

"Safety class interfaces between NNS CL-1 and NNS CL-2 shall be a single closed manual valve..." (Reference 6.10, Section 3.5)

The piping has been designed to withstand hydrostatic loads due to the flood event which are bounded by normal operation design loads. In addition, the safety class interface between piping performing a flood barrier function (NNS CL-1) and the remaining non-safety backwash piping (NNS CL-2) is isolated by a single closed manual valve. This is consistent with CQE List, Part One, Attachment V, ANSI/ANS 51.1-1983, Table 3-5, Note 4, which states that it shall not cause the loss of a nuclear safety function of SC-1, -2 or -3 equipment. This is accomplished by the use of passive components that are capable of withstanding much higher pressures and temperatures than those that occur during flood conditions. (Reference 6.15)

4.0 REGULATORY EVALUATION

4.1 Applicable Regulatory RequirementslCriteria 4.1.1 Regulations Code of Federal Regulations Part 50:

10 CFR Part 50.36, Technical Specifications, Criteria:

10 CFR 50.36(c)(2)(ii) states that, "A technical specification limiting condition for operation of a nuclear reactor must be established for each item meeting one or more of the following criteria:

LIC-13-0105 Enclosure Page 10 (A) Criterion 1 - Installed instrumentation that is used to detect, and indicate in the control room, a significant abnormal degradation of the reactor coolant pressure boundary.

(B) Criterion 2 - A process variable, design feature, or operating restriction that is an initial condition of a design basis accident or transient analysis that either assumes the failure of or presents a challenge to the integrity of a fission product barrier.

(C) Criterion 3 - A structure, system, or component that is part of the primary success path and which functions or actuates to mitigate a design basis accident or transient that either assumes the failure of or presents a challenge to the integrity of a fission product barrier.

(D) Criterion 4 - A structure, system, or component which operating experience or probabilistic risk assessment has shown to be significant to public health and safety."

There are no changes required to the current FCS Technical Specifications as a result of modification EC 55394 or the proposed USAR changes due to the classification of the sluice gates. However, LAR 12-03 (Reference 6.8) was submitted to the NRC in April 2012 to revise the TS 2.16, River Level, LCO applicability, objective, and requirements; to provide a new TS surveillance requirement for measurement of the river water level for verification that the Missouri River water level is within in its required limits; and to revise the Emergency Action Levels for flood level to 1004 ft. msl. This LAR also included information only changes to TS 2.16 Bases Section. OPPD is currently awaiting the NRC staff approval of this LAR.

10 CFR 50.36(c)(2) states, "When a limiting condition for operation of a nuclear reactor is not met, the licensee shall shut down the reactor or follow any remedial action permitted by the technical specifications until the condition can be met." There are no proposed revised TS actions, therefore this regulation is met.

10 CFR 50.36(c)(3) criteria states that "surveillance requirements are requirements relating to test, calibration, or inspection to assure that the necessary quality of systems and components is maintained, that facility operation will be within safety limits, and that the limiting conditions for operation will be met." Reliability centered inspections and maintenance overhauls, while important, do not meet the requirements set forth in 10 CFR 50.36 for incorporation into the TS, and are not activities that are generally used to demonstrate component operability. Therefore, this regulation is met by modification EC 55934.

10 CFR 50.65, Requirements for Monitoring the Effectiveness of Maintenance at Nuclear Power Plants: The overall objective of this performance-based rule is to ensure that nuclear power plant structures, systems, and components (SSCs) will be maintained so that they will perform their intended function when required. Modification EC 55394 implements preventive maintenance actions for the intake structure sluice gates and the new intake cell flood water inlet valves to ensure these components meet their intended functions for flood protection which meets the requirements of this regulation.

LIC-13-0105 Enclosure Page 11 General Design Criteria:

FCS Unit No. 1 was licensed for construction prior to May 21, 1971, and is committed to the draft General Design Criteria (GDC) published for comment in the Federal Register on July 11, 1967 (32 FR 10213) in lieu of 10 CFR 50, Appendix A. Appendix G of the FCS Updated Safety Analysis Report (USAR) shows that draft GDC 2 is most applicable to the proposed amendment.

CRITERION 2 - PERFORMANCE STANDARDS Those systems and components of reactorfacilities which are essential to the prevention of accidents which could affect public health and safety or to mitigation of their consequences shall be designed, fabricated, and erected to performance standardsthat will enable the facility to withstand, without loss of the capability to protect the public, the additionalforces that might be imposed by natural phenomena such as earthquakes, tornadoes, flooding conditions, winds, ice and other local site effects. The design bases so established shall reflect.- (a) Appropriate consideration for the most severe of these natural phenomena that have been recorded for the site and the surroundingarea and (b) an appropriatemargin for withstanding forces greaterthan those recorded to reflect uncertaintiesabout the historicaldata and their suitability as a basis for design.

This criterion is met. The systems and components of the Fort Calhoun Station, Unit No. I reactor facility that are essential to the prevention or mitigation of accidents that could affect public health and safety are designed, fabricated, and erected to withstand without loss of capability to protect the public, the additional forces that might be imposed by natural phenomena such as earthquakes,tornadoes, floods, winds, ice and other local site effects.

The containment will be designed for simultaneous stresses produced by the dead load, by 60 psig internal pressure at the associated design temperature, and by the application of forces resulting from an earthquake whose ground motion is 0.08g horizontally and 0.053g vertically. Further, the containment structure will be designed to withstand a sustained wind velocity of 90 mph in combination with the dead load and design internal pressure and temperature conditions. The wind load is based on the highest velocity wind at the site location for 100-year period or recurrence: 90 mph base wind at 30 feet above ground level. Other Class I structures will be designed similarly except that no internal pressure loading is applicable. Class I systems will be designed for their normal operating loads acting concurrently with the earthquake described above.

The containment structure is predicted to withstand without loss of function the simultaneous stresses produced by the dead load, by 75 psig internalpressure and temperature associated with this pressure and by an earthquake whose ground motion is 0. 10 horizontally and 0.07 vertically.

The containment structure is predicted to withstand without loss of function 125% of the force corresponding to a 90 mph wind impinging on the building concurrently with the stresses associated with the dead load and 75 psig internalpressure.

LIC-13-0105 Enclosure Page 12 With no earthquake or wind acting, the structure is predicted to withstand 90 psig internalpressure without loss of function.

Under each of these conditions, stresses in the structural members will not exceed 0. 95 yield.

The facility is designed so that the plant can be safely shutdown and maintained in a safe shutdown condition during a tornado. Design considerationsassociatedwith tornadoes are further explained in Section 5.4.7 of the USAR.

Flooding of Fort Calhoun Station, Unit No. 1 is considered highly unlikely.

Furtherinformation is available in USAR Section 2.7. 1.2.

The proposed LAR provides for implementation of modification EC 55394 for controlling intake structure cell water level during flood conditions. The physical changes being made to the plant and the associated USAR revisions to control in-flow to the intake cells provide protection of the RW pumps and the intake structure from an external flood hazard. This criterion will continue to be met.

4.1.2 Design Basis USAR Chapter 14 accident analyses assume availability of the Missouri River water (heat sink) based on the required availability of the RW pumps. The modification EC 55394 was installed for flood protection considerations. There are no USAR accident analyses impacted by the modification, the USAR Sections 2.7 and/or 9.8 revisions, or the proposed TS Basis revision.

As previously stated in Section 3.0, USAR Sections 2.7, Site and Environs, Hydrology, and 9.8, Auxiliary Systems, Raw Water System, are applicable to this LAR and OPPD is requesting NRC approval of the proposed changes as indicated.

4.1.3 Approved Methodologies There are no new plant-specific approved methodologies associated with this proposed LAR.

4.1.4 Analysis No new analyses were performed or needed in support of this proposed LAR.

4.2 Precedent There is no plant-specific precedence cited for this LAR for revising the current licensing basis due to safety classification.

LIC-13-0105 Enclosure Page 13 4.3 Significant Hazards Consideration The Omaha Public Power District (OPPD) has evaluated whether or not a significant hazards consideration is involved with the proposed amendment by focusing on the three standards set forth in 10 CFR 50.92, "Issuance of amendment," as discussed below:

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

Response: No.

The proposed modification engineering change (EC) 55394, Raw Water [RW]

Pump Operation and Safety Classificationof Components during a Flood, installed intake cell flood water inlet valves at Fort Calhoun Station (FCS). The modification would employ the trash rack blowdown portion of the circulating water system to allow river water to flow into four of those pipes and then through four newly installed safety class valves for control of cell level (RW pump suction level) using river level as the driving force. This modification EC 55394 enhances the flood protection provided to the RW pumps for an external flooding event thus assuring the availability of the ultimate heat sink and core cooling. As such, the proposed change does not increase the consequences of an accident previously evaluated.

In addition, implementing this strategy eliminates the need for the exterior sluice gates to be safety class and allows for continuous control of the intake cell level during a design basis flood event. The proposed Updated Safety Analysis Report (USAR) changes for implementing modification EC 55394 allow for maintaining RW pump operation during a flooding event at FCS.

Therefore, the proposed change does not involve a significant increase in the probability or consequences of an accident previously evaluated.

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

Response: No.

The proposed modification EC 55394 to provide control of the intake cell level by operation of the manual valves and the associated USAR changes do not alter the safety limits or safety analysis assumptions associated with the operation of the plant. Hence, the proposed changes do not introduce any new accident initiators, nor do they reduce or adversely affect the capabilities of any plant structure or system in the performance of their safety function. The proposed amendment revises the USAR to include the necessary information to support the implementation of the modification allowing for maintaining RW pump operation during an abnormal operating procedure AOP-01 flooding event at FCS.

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

LIC-13-0105 Enclosure Page 14

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

Response: No.

The proposed modification, which provides control of the intake cell level by operation of the manual valves, and the associated USAR changes do not alter the safety limits or safety analysis assumptions associated with the operation of the plant. The proposed modification and associated USAR revisions ensure there is adequate protection to the RW pumps from an external flood hazard thus assuring adequate protection during a flood. Providing RW pump intake cell level control during flooding conditions allows for adjustment of flow and control of the intake cell level throughout the duration of the flood since the new valves are located inside the intake structure; thereby ensuring the RW pumps remain operable during a flood condition and will not adversely impact any margin of safety.

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

Based on the above, OPPD concludes that the proposed amendment presents no significant hazards consideration under the standards set forth in 10 CFR 50.92(c),

and, accordingly, a finding of "no significant hazards consideration" is justified.

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 Commission's 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.

5.0 ENVIRONMENTAL CONSIDERATION

A review has determined that the proposed amendment would change a requirement with respect to installation or use of a facility component located within the restricted area, as defined in 10 CFR 20, or would change an inspection or surveillance requirement. However, the proposed amendment does not involve (i) a significant hazards consideration, (ii) a significant change in the types or significant increase in the amounts of any effluent that may be released offsite, or (iii) a significant increase in individual or cumulative occupational radiation exposure. Accordingly, the proposed amendment 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 amendment.

LIC-13-0105 Enclosure Page 15

6.0 REFERENCES

6.1 Engineering Analysis EA10-032, External Flooding Design Basis, Revision 1, dated February 16, 2011 (EC 51632) 6.2 Updated Safety Analysis Report (USAR) Appendix G, Responses to 70 Criteria,Revision 21, December 1,2011 6.3 Abnormal Operating Procedure, AOP-01, Acts of Nature, Revision 37 6.4 USAR Section 1.2, Summary and Plant Description, Component Cooling and Raw Water Systems, Revision 36, dated April 15, 2011 6.5 USAR Section 2.7, Site and Environs, Hydrology, Revision 12, dated July 19, 2012 6.6 USAR Section 5.11, Structures Other than Containment, Revision 11, dated December 12, 2012 6.7 USAR Section 9.8, Raw Water System, Revision 31, dated July 19, 2012 6.8 Letter from OPPD (D. J. Bannister) to NRC (Document Control Desk), License Amendment Request (LAR) 12-03, ProposedChange to Revise OperatingRequirements for Technical Specification 2.16, River Level, and Establish Emergency Action Level Classification Criteria for External Flooding Events under the Radiological Emergency Response Plan for Fort Calhoun Station, dated April 27, 2012 (LIC-12-0056)

(ML12121A565) 6.9 Letter from NRC (J. A. Clark) to OPPD (D. J. Bannister), Fort Calhoun - NRC Integrated Inspection Report Number 05000285/2012002, dated May 11, 2012 (NRC-1 2-0049) (EA-2012-095) (ML12132A395) 6.10 USAR, Appendix N, Reclassification of Systems, Revision 10, dated March 31, 2010 6.11 CQE List Part One-Section II, Mechanical and Structural, CQE List Requirements, Section 1.2.6.E(1), Revision 41, dated October 2, 2012 6.12 Modification Engineering Change (EC) 55394, Raw Water Pump Operation and Safety Classificationof Components during a Flood 6.13 USAR Appendix F, Classificationand Equipment and Seismic Criteria, Revision 10 6.14 Calculation FC07808, Intake Structure, Sub-structure Analysis, Revision 0 6.15 CQE List, Part One, Attachment V, Mechanical and Structural,ANSI/ANS-5.1-1983, Revision 24, dated May 17, 2005 6.16 Letter from NRC (M. Hay) to OPPD (L. P. Cortopassi), Fort Calhoun - NRC Inspection Report 05000285/2013011 and Notice of Violation, dated March 11, 2013 (NRC 0029) (EA-13-043)

LIC-13-0105 Enclosure, Attachment 1 Page 1 Updated Safety Analysis Pages Section 2.7 and 9.8 Mark-up Pages

[Word-processormark-ups using "redline-doubleunderline/strikeout"feature for "newtext/deleted text," respectively.]

Page 1 of 18 I USAR-2.7 Site and Environs Hydrology Rev 1-2 13 Safety Classification: Usage Level:

I Safety I Information Change No.: E4-56665 Reason for Change: ThIs USAR changc is' i;c...... to CR2012 02142 013, which requires the U-A- be udated with the design and licensing basis for protection of credited components from river borne debfis-.

Preparer: EdWards, M.I1A. Filips Issued: 07-4942--3:00 pmn Fort Calhoun Station

USAR-2.7 Information Use Page 8 of 18 Hydrology Rev. 1-213 The basis for providing passive protection to 1,007 feet is as stated in Reference 20:

It was recommended that based on Corps of Engineers' letter dated February 7, 1967 (Reference 12), and the flood data presented by them that the finished grade site elevation could safely be set at 1,004 feet since the 0.1% [Note, Reference 20 lists this value as 0.01%, which has subsequently been found to be a typographical error] probability flood is in this range. However, although the Corps of Engineers have stated that the 1952 flood should not be repeated because of better flood controls on the Missouri River, it is prudent to set the plant sill elevation at 1,007 feet as this was the high water mark according to local eye-witnesses at the Fort Calhoun site during this 1952 flood.

1,009.3 Feet The Corps of Engineers "preliminary estimate" of probable maximum flood that might occur as a result of runoff from a probable maximum rainstorm over the area below Gavins Point coupled with an assumed outflow of 50,000 CFS from Gavins Point reservoir is 1,009.3 feet (Reference 21).

Flooding protection against the 1,009.3 foot flood in the auxiliary building is provided by removable flood barriers which extend to 1014 feet. When required, these flood barriers are installed in openings leading to safety related equipment on the 1,007 foot floor elevation.

Flooding protection against the 1,009.3 foot flood in the intake structure is provided by removable flood barriers which extend to at least 1014 feet and intake cell level control maintained by the raw water pumps.

When required, these flood barriers are installed in all exterior openings on the operating level of the intake structure. In addition, a flood barrier is installed at the outlet of the screen wash discharge trough at the south end of the traveling screens. The intake cell level will be maintained below 1,007.5 feet by aduti' g j the exterior sluice gates to severely restrict flow in÷,to the cells, and then and throttlina the intake cell flood water inlet valves and/or varying the raw water pump output to remove the inlet flow. (Reference 39) 1,014 Feet The Corps of Engineers estimate of the flood level that might result from the failure of Oahe or Fort Randall dams coincident with the probable maximum flood that produces the 1,009.3 foot flood is 1,014 feet.

Page 1 of 14 USAR-9.8 I Auxiliary Systems Raw Water System Rev 34 32 Safety Classification: Usage Level:

II Safety It Information Change No.: EC 56563 I EC 56655 Reason for Change: Revising dcI of sluice gatc and raw water pump operation during a flood to r-eflect the intended functions as originally included in the FSAR and iMncorrectly removed by EC 29062 (USAR 9.8, RIO). f This USAR change i" in rpn. %seto CR2012042142 013, which requires the USRb updated with the design and IIensing basis for-protection Of credited

____________________ omponents from river borne debris-.

Preparer: Scofield, C. I Edwards.,,M Owner: Nuclear Licensing Issued: 0719*942 30*.pn Fort Calhoun Station

USAR-9.8 Information Use Page 10 of 14 Raw Water System Rev. 3432 Air accumulators inside the intake structure provide instrument air to operate the raw water system valves in the intake structure even upon failure of the Instrument Air system. The air-operated raw water strainer back flush valves (HCV-2805A/B),

however, do not have air accumulators. These valves fail to the open position upon loss of instrument air.

Water level instrumentation in the intake structure will alarm in the control room if water from any source should endanger the raw water pumps.

Protection for the raw water pumps and their drives against floods is provided at three elevations as indicated on Figure 9.8-1. The pumps are permanently protected against any water level up to elevation 1,007.5 feet by the Class I concrete substructure of the intake building. See Section 2.7 for additional information. Protection against the 1,009.3 foot and 1,014 foot floods (discussed below) is provided by gasketed steel closures at exterior doorway openings and the screen wash discharge trough. The water level inside the intake cells can be controlled by pre positioning c- n the exterior sluice gates (i.e., before floodwater reaches the elevation that prevents access to the sluice gate actuators) fe-seizefehy restrict the inflow...into the ce. ntake cell level is then Gcntrolled by and throttli the intake cell flood water inlet valves and/or varying the raw water pump output to remove the inlet flow.

If the celinortake through the river wluice gates is blocked during flooding ondition (possibly due to debris or other failure fechanism) an alternate flow path tothe cells can be provided by allowing flow backward through oe of the circulating pumps. Cell level would then l beontroted using either the iwate pump discharge valve or suction gate. This flow path meay also be used during exlrem floodingconditions if the river flow has a high dekris loaed to minirize sand/debris buildup inthe ell. (The plant must be shutdown with the cirfcuating water system The reinforced concrete perimeter walls of the intake structure extend to elevation 1,014.5 feet. However, above 1,007.5 feet MSL, the walls are designed only for the hydrostatic load from a 1,014 foot flood.

For further information on flood protection, see Section 2.7 Theoretical flood levels:

1,009.3 feet Computed peak level flood resulting from the simultaneous occurrence of:

1. The maximum probable rain storm and runoff downstream from Gavins Point;

2. The maximum outflow from Gavins Point resulting from a maximum probable rain storm and runoff upstream from Gavins Point.

LIC-13-0105 Enclosure, Attachment 2 Page 1 Updated Safety Analysis Report (USAR)

Sections 2.7 and 9.8 Retyped ("Clean") Pages

USAR-2.7 Information Use Page 8 of 18 Hvdrolocly Rev. 13 II USAR-2.7 I Site and Environs Hydrology Rev 13 Safety Classification: Usage Level:

Safety Information Change No.: EC 55394 Reason for Change: This USAR change is to implement Amendment No.

Preparer:

Issued: 3:00 pm Fort Calhoun Station

USAR-2.7 Information Use Page 8 of 18 Hydrology Rev. 13 The basis for providing passive protection to 1,007 feet is as stated in Reference 20:

It was recommended that based on Corps of Engineers' letter dated February 7, 1967 (Reference 12), and the flood data presented by them that the finished grade site elevation could safely be set at 1,004 feet since the 0.1% [Note, Reference 20 lists this value as 0.01%, which has subsequently been found to be a typographical error] probability flood is in this range.

However, although the Corps of Engineers have stated that the 1952 flood should not be repeated because of better flood controls on the Missouri River, it is prudent to set the plant sill elevation at 1,007 feet as this was the high water mark according to local eye-witnesses at the Fort Calhoun site during this 1952 flood.

1,009.3 Feet The Corps of Engineers "preliminary estimate" of probable maximum flood that might occur as a result of runoff from a probable maximum rainstorm over the area below Gavins Point coupled with an assumed outflow of 50,000 CFS from Gavins Point reservoir is 1,009.3 feet (Reference 21).

Flooding protection against the 1,009.3 foot flood in the auxiliary building is provided by removable flood barriers which extend to 1014 feet. When required, these flood barriers are installed in openings leading to safety related equipment on the 1,007 foot floor elevation.

Flooding protection against the 1,009.3 foot flood in the intake structure is provided by removable flood barriers which extend to at least 1014 feet and intake cell level control maintained by the raw water pumps. When required, these flood barriers are installed in all exterior openings on the operating level of the intake structure. In addition, a flood barrier is installed at the outlet of the screen wash discharge trough at the south end of the traveling screens. The intake cell level will be maintained below 1,007.5 feet by closing the exterior sluice gates and throttling the intake cell flood water inlet valves and/or varying the raw water pump output to remove the inlet flow. (Reference 39) 1,014 Feet The Corps of Engineers estimate of the flood level that might result from the failure of Oahe or Fort Randall dams coincident with the probable maximum flood that produces the 1,009.3 foot flood is 1,014 feet.

USAR-9.8 Information Use Page 10 of 14 Raw Water System Rev. 32 USAR-9.8 Auxiliary Systems Raw Water System Rev 32 Safety Classification: Usage Level:

I Safety I Information Change No.: EC 55394 Reason for Change: Revise USAR to Implement Amendment No.

Preparer:

Owner: Nuclear Licensing Issued: 3:00pm Fort Calhoun Station

USAR-9.8 Information Use Page 10 of 14 Raw Water System Rev. 32 Air accumulators inside the intake structure provide instrument air to operate the raw water system valves in the intake structure even upon failure of the Instrument Air system. The air-operated raw water strainer back flush valves (HCV-2805A/B),

however, do not have air accumulators. These valves fail to the open position upon loss of instrument air.

Water level instrumentation in the intake structure will alarm in the control room if water from any source should endanger the raw water pumps.

Protection for the raw water pumps and their drives against floods is provided at three elevations as indicated on Figure 9.8-1. The pumps are permanently protected against any water level up to elevation 1,007.5 feet by the Class I concrete substructure of the intake building. See Section 2.7 for additional information. Protection against the 1,009.3 foot and 1,014 foot floods (discussed below) is provided by gasketed steel closures at exterior doorway openings and the screen wash discharge trough. The water level inside the intake cells can be controlled by closing the exterior sluice gates and throttling the intake cell flood water inlet valves and/or varying the raw water pump output to remove the inlet flow.

The reinforced concrete perimeter walls of the intake structure extend to elevation 1,014.5 feet. However, above 1,007.5 feet MSL, the walls are designed only for the hydrostatic load from a 1,014 foot flood.

For further information on flood protection, see Section 2.7 Theoretical flood levels:

1,009.3 feet Computed peak level flood resulting from the simultaneous occurrence of:

1. The maximum probable rain storm and runoff downstream from Gavins Point;

2. The maximum outflow from Gavins Point resulting from a maximum probable rain storm and runoff upstream from Gavins Point.

LIC-1 3-0105 Enclosure, Attachment 3 Page 1 Technical Specifications Bases Page Information Only Markups TS 2.16 Bases - Information only Total Attached Pages - 1

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TECHNICAL SPECIFICATIONS 2.0 LIMITING CONDITIONS FOR OPERATION 2.16 River Level Applicability Applied to Missouri River level as measured at the intake structure at the Fort Calhoun Station.

Objective To specify maximum and minimum Missouri River levels which must be present to assure safe reactor operation.

Specifications

1) If the Missouri River level exceeds 1009(1) feet the reactor will be placed in a cold shutdown condition using normal operating procedures. When the river level reaches elevation 1004.2 feet and rising, the emergency plan to protect the plant will be instituted.

(2) If the Missouri River level is less than 976 feet 9 inches the reactor will be placed in a cold shutdown condition using normal operating procedures. At river levels less than 980 feet a continuous watch will be maintained to assure no sudden loss of water supply occurs.

Basis At the Fort Calhoun Station (FCS) site, the probable maximum flood that might occur as a result of runoff from a probable maximum rainstorm over the area below the Gavins Point dam coupled with an assumed outflow of 50,000 cubic feet per second from Gavins Point reservoir is 1009.3 feet. In the unlikely event that the Oahe or Fort Randall dams fail at that time, the Corps of Engineers has estimated that the flood level could be as high as 1014 feet(1 ).

The intake structure can be protected from these Missouri River floods using removable flood gates on doorways and the screen wash discharge trough. The water level inside the intake cells can be controlled by p.**tiRi..g c the exterior sluice gates and throttling the intake cell flood water inlet valves and/or to re ic.nt ells and then.,varying the raw water pump output to remove the inlet flow. The auxiliary building can be protected to 1009.5 feet using its installed flood gates. Protection of the auxiliary building to 1014 feet requires the installation of removable flood barriers and sandbagging at the 1013 foot elevation of the equipment hatch room (Room 66).

The minimum river level of 976 feet 9 inches provides adequate suction to the raw water (RW) pumps for cooling plant components. The minimum elevation of the RW pump suction is 973 feet 9 inches. An intake cell level of 976 feet 9 inches is required for RW pump minimum submergence level (MSL)(2). The partial loss of this supply is considered highly unlikely.

However, provisions for low water levels during winter and spring ice conditions are considered necessary. When river level is low, head loss from debris and/or ice on the traveling screens and/or trash racks could reduce intake cell levels such that the required RW pump MSL is not achieved. This could lead to pump degradation from the formation of vortices at the free water surface. Thus, when the continuous watch requirement is in effect, in addition to river level, the level of the intake cells is monitored.*

2.16 - Page 1 TSBC-07-002-0, TSBC-10-001-0, TSBC-1 0-003-0

LIC-1 3-0105 Enclosure, Attachment 4 Page 1 Retyped ("Clean")

Technical Specifications Bases Page Information Only TS Bases 2.16 - Page 1 (Information only)

Total Attached Pages - I

-CHNICAL SPECIFICATIONS 2.0 LIMITING CONDITIONS FOR OPERATION 2.16 River Level Applicability Applied to Missouri River level as measured at the intake structure at the Fort Calhoun Station.

Objective To specify maximum and minimum Missouri River levels which must be present to assure safe reactor operation.

Specifications

1) If the Missouri River level exceeds 1009(1) feet the reactor will be placed in a cold shutdown condition using normal operating procedures. When the river level reaches elevation 1004.2 feet and rising, the emergency plan to protect the plant will be instituted.

(2) If the Missouri River level is less than 976 feet 9 inches the reactor will be placed in a cold shutdown condition using normal operating procedures. At river levels less than 980 feet a continuous watch will be maintained to assure no sudden loss of water supply occurs.

Basis At the Fort Calhoun Station (FCS) site, the probable maximum flood that might occur as a result of runoff from a probable maximum rainstorm over the area below the Gavins Point dam coupled with an assumed outflow of 50,000 cubic feet per second from Gavins Point reservoir is 1009.3 feet. In the unlikel event that the Oahe or Fort Randall dams fail at that time, the Corps of Engineers has estimated that the flood level could be as high as 1014 feet *.

The intake structure can be protected from these Missouri River floods using removable flood gates on doorways and the screen wash discharge trough. The water level inside the intake cells can be controlled by closing the exterior sluice gates and throttling the intake cell flood water inlet valves and/or-varying the raw water pump output to remove the in[et flow. The auxiliary I

building can be pr6tected to 1009.5 feet using its installed flood gates. Protection of the auxiliary building to 1014 feet requires the installation of removable flood barriers and sandbagging at the 1013 foot elevation of the equipment hatch room (Room 66).

The minimum river level of 976 feet 9 inches provides adequate suction to the raw water (RW) pumps for cooling plant components. The minimum elevation of the RW pump suction is 973 feet 9 inches. An intake cell level of 976 feet 9 inches is required for RW pump minimum submergence level (MSL)(2). The partial loss of this supply is considered highly unlikely.

However, provisions for low water levels during winter and spring ice conditions are considered necessary. When river level is low, head loss from debris and/or ice on the traveling screens and/or trash racks could reduce intake cell levels such that the required RW pump MSL is not achieved. This could lead to pump degradation from the formation of vortices at the free water surface. Thus, when the continuous watch requirement is in effect, in addition to river level, the level of the intake cells is monitored.*

2.16 - Page 1 TSBC-07-002-0 TSBC-10-001-0 TSBC-1 0-003-0 TSBC-I

5 3

LIC-1 Attachment EnclOsure, 1

Figure

/1

/Raw Water PUMPS I~

ý Ct~$kSs.