Text

Flooding Walkdown Report in Response to the 50.54(f) Information Request Re Near-Term Task Force Recommendation 2.3: Flooding.
	ML123350124
Person / Time
Site:	Fort Calhoun
Issue date:	11/02/2012
From:	Pandit B; Sargent & Lundy
To:	; Office of Nuclear Reactor Regulation, Omaha Public Power District
Shared Package
ML123350126	List: LIC-12-0170, 180-Day Response to NRC Request for Information Re Flooding Aspects of Recommendation 2.3 of Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident; ML123350124;
References
	LIC-12-170
	Download: ML123350124 (52)
	v • d • e

FLOODING WALKDOWN REPORT IN RESPONSE TO THE 50.54(f) INFORMATION REQUEST REGARDING NEAR-TERM TASK FORCE RECOMMENDATION 2.3: FLOODING for the FORT CALHOUN STATION 9610 POWER LANE, BLAIR, NE 68008 Facility Operating License No. DPR-40 NRC Docket No. 50-285 Omaha Public Power District 444 South 16th Street Mall Omaha,. NE 68102-2247 Prepared by:

Sargent,& Lundy LLC 55'E; Monroe Chicago IL, 60603 SL-011503, Rev. 0 November 2, 2012 Printed Name/Title Affiliation Signature Date Preparer: Bansi Pandit/ Sargent & Lundy Prepaer: ___ Lundv . ' 11-2/. 12 Program Manager . ....

Brian Jelke/

Reviewer: Brianaeer Sargent & Lundy .

Project Manager x 4 v i* i_

Approver: Joseph Gasper

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. ...Omaha .- /) . I Carmen Ovici . ......

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NTTF Recommendation 2.3 (Walkdowns): Flooding Fort Calhoun Station Revision 0 Contents

1. EXECUTIVE SUM MARY ............................................................................................................................... 2

2. PURPOSE ........................................................................ ........................................................................... 3

a. Ba ckg ro u n d ........................................................................................................................................... 3

b. Site De scrip tio n ..................................................................................................................................... 4

c. Requested Actions ................................................................................................................................ 5

d. Requested Inform ation ......................................................................................................................... 5

3. M ETHODOLOGY ......................................................................................................................................... 5

a. Overview of NEI 12-07 (W alkdow n Guidance) ................................................................................. 5

b. Application of NEI 12-07 .............................................................................................................. 5

c. Reasonable Sim ulations .............................................................................................................. 6

d. W alkdow n Inspection Guidance ...................................................................................................... 7

4. RESULTS ...................................................................................................................................................... 7

a. Requested Inform ation Item 2(a) - Design Basis Flood Hazards ..................................................... 7

b. Requested Information Item 2(b) -CLB Protection and Mitigation Features ................................ 8

c. Requested Inform ation Item 2(c) - Flood W arning System s .......................................................... 9

d. Requested Information Item 2(d) - Flood Protection System/Barrier Effectiveness .................... 10

e. Requested Information Item 2(e) - Implementation of Walkdown Process ................................ 11

f. Requested Information Item 2(f) - Findings and Corrective Actions Taken/Planned ................... 12

g. Requested Information Item 2(g) - Cliff-Edge Effects and Available Physical Margin .................. 13

h. Requested Information Item 2(h) - Planned/Newly-Installed Flood Protection Enhancements ....... 13

5. CONCLUSIONS .......................................................................................................................................... 14

6. REFERENCES ............................................................................................................................................. 17

7. ATTACHM ENTS ........................................................................................................................................ 17 Page 1

NTTF Recommendation 2.3 (Walkdowns): Flooding Fort Calhoun Station Revision 0

1. EXECUTIVE

SUMMARY

In response to the NRC Request for Information regarding Near Term Task Force (NTTF) Recommendation 2.3, a flooding protection walkdown was conducted at Fort Calhoun Station (FCS) to identify and address plant-specific degraded, nonconforming, or unanalyzed conditions of the plant's flood protection features.

The flooding walkdown was conducted between September 14 and October 5, 2012 and included visual inspections of flood protection features and a walk-thru of the applicable flood protection procedure steps.

However, during this period access to sixty seven (67) penetrations was restricted due to construction activities or because access to these penetrations requires additional maintenance support or lack of reasonable physical access. Inspections of these barriers will be conducted upon completion of construction activities which will allow access to these barriers, with the exception of three areas which are considered inaccessible. These inspections will be completed by March 31, 2013.

The scope of the flooding walkdown was developed following a detailed review of all relevant current licensing documents. The flooding walkdown scope consisted of the following three main parts:

" The credited flood protection features in the Intake Structure, Auxiliary Building and Containment were inspected.

" An outdoor walkdown was conducted to ensure no topography changes, added structures or security barriers affect site drainage as described in the current licensing basis (CLB).

" The below-grade structures (i.e., basement walls and basement slabs and penetrations through these walls and floors) in the Intake Structure, Auxiliary Building and Containment were inspected.

These areas are credited in the CLB to keep groundwater and runoff from local rainfall out of the safety related buildings.

The methodology and acceptance criteria for the evaluation of flood protection features were based on NEI report 12-07 [Rev O-A], Guidelinesfor Performing Verification Walkdowns of PlantProtectionFeatures.

Visual inspections of walls, floors and penetrations through the walls and floors were conducted to verify there are no observable structural deficiencies that may impact the structure's ability to remain watertight.

The inspections of walls, floors and penetrations confirmed that credited flood barriers are in place and no deficiencies were identified that render these features incapable of performing their intended function.

Reasonable simulation of the flood protection procedures was not conducted. In place of the simulations, the data from the installation of new flood barriers in March 2011 and the procedures used for installation of these barriers during the flood of summer 2011 at FCS were used to demonstrate that the FCS procedures that cover implementation of the flood protection strategy can be executed as written. All CRs entered into the CAP have been addressed and are not deficiencies.

Whether conduits from manholes or cable vaults could provide a path for ground water or rain water to enter safety related buildings was considered relative to the walkdown scope. When conduits from manholes/cable vaults are routed to the safety related buildings, water sealed (Flood Protected) penetrations are provided. The walkdown scope included inspections of the external conduit seals. Internal conduit seals could not be visually inspected; however, plant design documentation provides reasonable assurance that the internal seals are installed, and evidence of groundwater/rainwater leakage through Page 2

NTTF Recommendation 2.3 (Walkdowns): Flooding Fort Calhoun Station Revision 0 conduits into safety related buildings at FCS was not identified during the walkdowns. Conduits at FCS do not provide a path for ground water or rain water to enter safety related buildings.

As an enhancement, FCS is in the process of installing wireless level measurement devices in manholes containing safety related cables. Installing the new level instrumentation will provide a reliable way to monitor the level of water in the manholes. It will also provide a tool for the plant to observe the pattern of water inleakage into manholes.

Visual inspection of the sluice gates in the Intake structure, which are active flood protection components within the walkdown scope, was not performed because they are located under water. However, these features are acceptable based on the fact that they are used during normal operation and are covered by the station's preventive maintenance program that periodically checks their integrity and function.

Performance of the walkdowns provided confirmation that flood protection features are in place, are in good condition and will perform as credited in the current licensing basis. Minor issues identified were addressed and dispositioned under the CAP program.

A total of 14 CRs were entered into the CAP as a result of this effort. These are described in Table 2 in the Conclusions section of this report. The outcome of the CAP dispositions identified no deficiencies as defined in NEI 12-07.

2. PURPOSE

a. Background In response to the nuclear fuel damage at the Fukushima-Dai-ichi power plant due to the March 11, 2011 earthquake and subsequent tsunami, the United States Nuclear Regulatory Commission (NRC) established the Near Term Task Force (NTTF) to conduct a systematic review of NRC processes and regulations, and to make recommendations to the Commission for its policy direction. The NTTF issued a set of recommendations that were intended to clarify and strengthen the regulatory framework for protection against natural phenomena.

On March 12, 2012, the NRC issued an information request pursuant to Title 10 of the Code of Federal Regulations, Section 50.54 (f) (10 CFR 50.54(f) or 50.54(f)) (Reference 3), which included the following six (6) enclosures:

" [NTTF] Recommendation 2.1: Seismic

[NTTF] Recommendation 2.1: Flooding

[NTTF] Recommendation 2.3: Seismic

[NTTF] Recommendation 2.3: Flooding

" [NTTF] Recommendation 9.3: EP

Licensees and Holders of Construction Permits In Enclosure 4 of Reference 3, the NRC requested that licensees 'perform flood protection walkdowns to identify and address plant-specific degraded, nonconforming, or unanalyzed conditions and cliff-edge effects (through the corrective action program) and verify the adequacy of monitoring and maintenance procedures'. (See note below regarding 'cliff-edge effects'.)

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NTTF Recommendation 2.3 (Walkdowns): Flooding Fort Calhoun Station Revision 0 This report provides the information requested in the March 12, 50.54(f) letter; specifically, the information listed under the 'Requested Information' section of Enclosure 4, paragraph 2 ('a' through 'h') (Reference 3).

The 'Requested Information' section of Enclosure 4, paragraph 1 ('a' through 'j'), regarding flooding walkdown procedures, was addressed via OPPD's June 8, 2012 (Reference 1), acceptance of the industry walkdown guidance (Reference 2).

Note Regarding Cliff-Edge Effects Cliff-edge effects were defined by the NTTF Report (Reference 5), which noted that 'the safety consequences of a flooding event may increase sharply with a small increase in the flooding level'. While the NRC used the same term as the NTTF Report in the March 12 50.54(f) information request (Reference 3), the information the NRC expects utilities to obtain during the Recommendation 2.3: Flooding Walkdowns is different. To clarify, the NRC is now differentiating between cliff-edge effects (which are dealt with under Enclosure 2 of Reference 3) and a new term, Available Physical Margin (APM). APM information will be collected during the walkdowns, but will not be reported in the response to Enclosure 4 of Reference 3. The collected APM information will be available for use in developing the response to of Reference 3.

b. Site Description The Fort Calhoun Station (FCS) is located on the west bank of the Missouri River, approximately 19 miles north of Omaha, and 3 miles southeast of Blair. The plant site is bounded on the northeast and southeast by a portion of Blair Bend of the Missouri River. The Corps of Engineers (CoE) maintains river structures to prevent further meandering of the channel within the alluvial flood plain; the structures take the form of pile dikes and bank revetments. There are six dams upstream of the plant site that control the river flow.

These structures are listed in the table below in the order from the nearest to the site (Gavins Point) to the most distant (Fort Peck). There are no dams, locks, or similar structures on the Missouri downstream of the plant site.

MISSOURI RIVER DAMS Name Location Near Year of Initial Operation Gavins Point Yankton, South Dakota 1956 Fort Randall Lake Andes, South Dakota 1953 Big Bend Chamberlain, South Dakota 1964 Oahe Pierre, South Dakota 1962 Garrison Bismarck, North Dakota 1956 Fort Peck Glasgow, Montana 1940 The structures that house safety-related equipment are the Containment, Auxiliary Building and Intake Structure. The site grade elevation is nominally set at 1004.5 feet above main sea level (MSL). The probable maximum flood (PMF) for FCS resulting from maximum rainfall downstream of the Gavins Point dam and an assumed maximum outflow from the Gavins Point dam would produce a peak flood elevation of approximately 1009.3 feet MSL. The failure of Oahe or Fort Randall combined with a probable maximum flood from a storm below Gavins Point Dam would produce a flood peak of about 1013 to 1014 feet MSL (Reference 9).

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NTTF Recommendation 2.3 (Walkdowns): Flooding Fort Calhoun Station Revision 0

c. Requested Actions Per Enclosure 4 of Reference 3, the NRC requests that each licensee confirm use of the industry-developed, NRC-endorsed, flood walkdown procedures or provide a description of plant-specific walkdown procedures.

In a letter dated June 8, 2012 (Reference 1), OPPD confirmed that the flooding walkdown procedure (Reference 2), endorsed by the NRC on May 31, 2012, will be used as the basis for the flooding walkdowns.

d. Requested Information Per Enclosure 4 of Reference 3,

1. The NRC requests that each licensee confirm that it will use the industry-developed, NRC endorsed, flooding walkdown procedures or provide a description of plant-specific walkdown procedures. As indicated previously, OPPD's letter dated June 8, 2012 (Reference 1), confirmed that the flooding walkdown procedure (Reference 2), endorsed by the NRC on May 31, 2012, will be used as the basis for the flooding walkdowns.

2. The NRC requests that each licensee conduct the walkdown and submit a final report which includes the results of the walkdown including key findings and identified degraded, nonconforming, or unanalyzed conditions.

3. METHODOLOGY

a. Overview of NEI 12-07 (Walkdown Guidance)

In a collaborative effort with NRC staff, NEI developed and issued report 12-07 [Rev O-A], Guidelinesfor Performing Verification Wolkdowns of Plant Protection Features, dated May 2012 (Reference 2). The NRC endorsed NEI 12-07 on May 31, 2012 with amendments. NEI 12-07 was updated to incorporate the amendments and re-issued on June 18, 2012. On June 8, 2012, OPPD issued a letter to the NRC (Reference 1) stating that the endorsed flooding walkdown procedure (Reference 2) will be used as the basis for the flooding walkdowns.

b. Application of NEI 12-07 OPPD's approach to the flooding walkdowns included the following three phases:

Phase 1 - Preparation, Training, Data Gathering, and Scoping OPPD developed and presented a training course for walkdown team members to ensure a complete and consistent implementation of NEI 12-07 guidelines. In addition, all walkdown team members completed the applicable NANTeL training and testing. Data gathering began with identification of station-specific licensing commitments and station design basis relative to external flooding events. This included review of the Fort Calhoun Station Updated Safety Analysis Report (USAR) (Reference 7), identification of drawings showing flood protection features and review of station procedures and calculations relative to external flooding events. A walkdown scope was developed to ensure station features credited as performing a flood protection function in the current licensing basis would be inspected. Based on the walkdown scope a walkdown list (see Attachment A) was prepared identifying the specific features to be inspected. For each feature on the walkdown list a walkdown package was prepared for use by the walkdown team in performing and documenting the walkdown.

The, scope developed for the walkdowns at FCS included the following:

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NTTF Recommendation 2.3 (Walkdowns): Flooding Fort Calhoun Station Revision 0

" The floors and exterior watertight walls (up to PMF elevation of 1014 feet) of the Auxiliary building and the Intake structure. Scope included inspection of all penetrations and watertight doors in the walls inspected. Interior walls between rooms were not inspected.

The Containment building was not included in the inspection scope because the exterior walls and the floor may be credited with leak tightness based on the periodic ILRT testing.

" Whether conduits from manholes or cable vaults could provide a path for ground water or rain water to enter safety related buildings was considered relative to the walkdown scope.

When conduits from manholes/cable vaults are routed to the safety related buildings, water sealed (Flood Protected) penetrations are provided. The walkdown scope included inspections of the external conduit seals. Internal conduit seals could not be visually inspected but were confirmed to be installed by reviewing the associated design and construction drawings. Evidence of groundwater/rainwater leakage through conduits into safety related buildings at FCS has not been identified in the past and was not identified during the walkdowns. Conduits at FCS do not provide a path for ground water or rain water to enter safety related buildings.

An outdoor walkdown to identify topography changes was conducted and documented in the NEI 12-07 Walkdown Record Form. The visual inspection of the site and the review of the grade elevations shown on the most recent site topographic map confirmed that no topography changes, added structures or security barriers affected site drainage as described in the CLB.

Phase 2 - Inspections and Reasonable Simulations Visual inspection of each feature was performed during the walkdowns and the results were documented on the Walkdown Record Forms. The condition of each feature as observed was compared to the acceptance criteria defined in NEI 12-07. See item 3C below for a discussion of reasonable simulations.

Phase 3 - Final Reporting The Walkdown Record Forms were completed and assembled into a package that included a list of credited flood protection feature at FCS as shown in Attachment A. Completion of the Walkdown Record Forms was performed in accordance with the guidance provided in Section 7 of NEI 12-07.

A Flooding Walkdown Report (this report) was prepared to address the items outlined in the "Requested Information" section of the "Recommendation 2.3: Flooding" enclosure from the 10CFR5O.54 (f) letter 07.

c. Reasonable Simulations The purpose of reasonable simulations is to verify required flood protection procedures or activities can be executed as specified/written.

Fort Calhoun Station flood protection features do include temporary or active features that require implementation of a procedure for performance of manual/operator actions in order for the feature to perform its intended flood protection function. Therefore, procedure walk-through was conducted at Fort Calhoun Station. However, reasonable simulation of the flood protection procedures was not conducted. In place of the simulations the verifications completed as part of the process of installing new flood barriers in March 2011 and the procedures used for installation of the barriers during the flood of summer 2011 at FCS were used to demonstrate that the FCS Page 6

NTTF Recommendation 2.3 (Walkdowns): Flooding Fort Calhoun Station Revision 0 procedures that cover implementation of the flood protection strategy can be executed as written.

Where degraded, non-conforming or unanalyzed conditions were identified, these findings were documented and entered into the station corrective action program.

d. Walkdown Inspection Guidance Walkdown inspection guidance from NEI 12-07 (Reference 2) was used for specific features, listed below, as applicable.

Incorporatedor Exterior Passive Features:

o Site Elevations and Topography o Earthen Features(i.e., Flood Protection Berm, Dike, Levee) o Concrete and Steel Structures o Wall, Ceiling, and Floor Seals (e.g. PenetrationSeals, Cork Seals) o Passive Flood Barriers or Water Diversion Structures o Drainsand Catch Basins o Plugs and Manhole Covers o DrainagePathways (Swales, Subsurface DrainageSystem, etc.)

o Piping and Cable Vaults and Tunnels, Electrical Cable Conduit o FloorHatches o Flap Gate/Backwater Valve/Duckbill Valve o Flood Wall

Incorporatedor Exterior Active Features:

o CreditedWater Tight Doors o CreditedNon- WatertightDoors o Pumps o Water Level Indication o Gate Valves

Temporary Passive Features:

o PortableFlood Barriers and Inflatable Rubber Seals o Flood Gate

" Temporary Active Feature o Pumps The FCS specific flood protection features that were walked down are listed in Attachment A.

4. RESULTS The information requested in Reference 3, Enclosure 4, under paragraph 2 of the 'Requested Information' section, is provided below. The contents of each item were developed in accordance with Reference 2, Appendix D.

a. Requested Information Item 2(a) - Design Basis Flood Hazards Describe the design basis flood hazard level(s) for all flood-causing mechanisms, including groundwater ingress.

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NTTF Recommendation 2.3 (Walkdowns): Flooding Fort Calhoun Station Revision 0 The Fort Calhoun Station (FCS) design basis for external flooding is described in FCS USAR Sections 2.7 and 9.8 (Reference 7) and PLDBD-CS-56 (Reference 9). FCS is designed to be protected from the effects of river flooding and local rainwater.

The Fort Calhoun Station was licensed in accordance with the draft criteria set forth in the 70 General Design Criteria for Nuclear Power Plant Construction, which were published for comment in the Federal Register (32 FR 10213) on July 11, 1967. Appendix A, Criterion 2 of USAR (Reference 7) defines the FCS design criterion for external flooding. FCS is not committed to later codes and standards related to flooding such as Reg. Guide 1.59, Design Basis Floods for Nuclear Power Plants, dated August 1977 or Reg. Guide 1.102. FCS was not analyzed for certain conditions required by later codes and standards.

Per the current licensing basis (CLB), FCS is not analyzed for Probable Maximum Precipitation (PMP) as defined in NEI 12-07. FCS Design Basis includes maximum rainfall (not PMP). Flood time duration is not discussed in the CLB. However, seven (7) days on-site supply requirements are assumed. Per the CLB, hurricane surge and seiche are not applicable to the FCS Design Basis.

During review of the Preliminary Safety Analysis Report (PSAR), the Atomic Energy Commission requested consideration of Probable Maximum Flood (PMF) (without a dam failure) and PMF coincident with a hydrologically induced dam failure. The probable maximum flood (PMF) resulting from maximum rainfall downstream of the Gavins Point dam and an assumed maximum outflow from the Gavins Point dam would produce a peak flood elevation of approximately 1009.3 feet MSL. The failure of Oahe or Fort Randall Dam would require a pyramiding of additional maximum probable conditions beyond those specified. But assuming such a failure and timing it critically with a probable maximum flood from a storm below Gavins Point Dam would produce a flood peak of about 1013 to 1014 feet.

The elevations for the PMFs with and without dam failure did not include wave action. Based upon the current licensing basis, it is a regulatory requirement to protect the plant for external flooding levels less than or equal to 1014 feet, based on a PMF coincident with an Oahe or Fort Randall Dam Failure.

b. Requested Information Item 2(b) - CLB Protection and Mitigation Features Describe protection and mitigation features that are considered in the licensing basis evaluation to protect againstexternalingress of water into SSCs importantto safety.

Safety related equipment at Fort Calhoun Station that could be impacted by flooding is located in the Containment, Auxiliary Building and Intake Structure. The Containment structure is provided with passive flood protection. The personnel access hatch and equipment hatch penetrations are located such that the lower elevation of the penetrations is at elevation 1011.5 feet. Containment penetrations may be open during plant shutdown modes. Flood barriers installed in the Auxiliary Building provide protection to 1014 feet for Containment and Auxiliary Building mechanical and electrical penetrations below that elevation. The Containment design includes the effect of external hydrostatic loads resulting from a maximum flood level of elevation of 1014 feet (Reference 7, Section 5.4.9).

Permanent passive protection for the Auxiliary Building and Intake Structure is provided to a level of 1007 feet. This passive protection is accomplished by placing openings to portions of these structures containing safety related equipment above 1007 feet. Below 1007 feet, portions of these structures containing safety related equipment are constructed of sealed concrete. These structures were also designed for an external hydrostatic load due to flooding to elevation 1014 feet (Reference 7, Section 5.11).

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NTTF Recommendation 2.3 (Walkdowns): Flooding Fort Calhoun Station Revision 0 The railroad siding/truck bay (Room 25) on the west side of the Auxiliary Building is at elevation 1004 feet. However, flooding of the railroad siding would not affect systems or components necessary for plant operation, or for maintenance of safe shutdown for flood elevations to 1007 feet (without additional protection) or 1014 feet with flood barriers installed.

The Auxiliary Building is designed for an external hydrostatic load due to flooding up to elevation 1014 feet. Limited-CQE (Critical Quality Equipment) metal flood barriers are provided for protection of Auxiliary Building openings as needed, for flood levels between 1007 feet and 1014 feet. The design criterion for Auxiliary Building penetrations is that they are capable of sealing against the differential pressure of flood levels up to elevation of 1014 feet. Sandbagging is used inside the Auxiliary Building to control flooding in equipment hatch Room 66. The Safety Injection and Refueling Water Storage Tank (SIRWT) have two goose neck vents in Room 25. The tops of the vents are at approximately 1015 feet, and the hinge points are at approximately 1005 feet. Gaskets are installed at the hinge points to prevent flood water from entering the SIRWT.

The Intake Structure is designed for an external hydrostatic load due to flooding up to elevation 1014 feet. The design criterion for Intake Structure penetrations is that they are capable of sealing against the differential pressure of flood levels up to elevation of 1014 feet. Limited-CQE metal flood barriers are provided for protection of Intake Structure door openings for flood levels between the floor elevation of 1007.5 feet and the licensing basis flood level of 1014 feet.

Direct communication exists between the Intake Structure operating floor and the Circulating Water Pump cells. For cell levels above 1007.5 feet, throttling of the traveling screen sluice gates is performed to prevent flooding of the Intake Structure and Raw Water Pump vault via this path.

Sandbagging is also used inside the Intake Structure.

The planned operating strategy for floods greater than the site grade elevation of 1004.5 feet, and less than or equal to 1014 feet, is to place the plant on shutdown cooling. This approach uses the Shutdown Cooling System for decay heat removal, with primary-to-secondary heat removal available for additional margin.

The licensing basis does not discuss flood duration or assumed weather conditions concurrent with flooding. The only parameter that is affected by the duration is the ability to maintain station power by way of a diesel generator. Calculations have shown that power can be provided for 7 days if loads are minimized and only one diesel generator is running. Operations is provided with this guidance in the emergency flood protection procedures. It is assumed, although not stated, that the organization will provide a method for replenishing fuel oil supplies within that 7 day period, if needed.

The flood protection features at FCS are not dependent on weather. In addition, FCS flood protection features are designed to function during any plant mode of operation. The allowance for protection for floods is based on information provided by the Corps of Engineers that it would take approximately two days for a flood crest due to dam failure to travel from the Gavins Point reservoir to the Fort Calhoun plant site. This expected transit time provides sufficient warning time to shut down the plant and implement adequate emergency procedures. There are no time dependent actions required.

c. Requested Information Item 2(c) - Flood Warning Systems Describe any warning systems to detect the presence of water in rooms importantto safety.

FCS has no warning systems in rooms important to safety credited to detect flooding from external sources. During routine operations FCS monitors the Missouri River for conditions which would initiate Page 9

NTTF Recommendation 2.3 (Walkdowns): Flooding Fort Calhoun Station Revision 0 flood response actions. Flood response actions and entry conditions into the emergency flood protection procedures are initiated when one or more of the following exist:

- The National Weather Service or the U.S. Army Corps of Engineers forecasts the possibility of river level exceeding 1004 feet.

- River level reaches the 1000 foot level.

- Notification by the U.S. Army Corps of Engineers that an upstream dam or dams have failed with flooding expected in the Fort Calhoun area.

If notified by U.S. Army Corps of Engineers or county/state/federal authorities that an upstream dam or dams have failed or are anticipated to fail with flooding expected to exceed 1004 feet MSL in the Fort Calhoun area, the Emergency Response Plan will be activated immediately to allow for longest lead times to safely shutdown the plant and maintain it in a safe shutdown condition. Based on the information provided by U. S. Army Corps of Engineers, it would take approximately two days for a flood crest due to dam failure to travel from the Gavins Point reservoir to the Fort Calhoun plant site.

This expected transit time provides sufficient warning time to shut down the plant and implement adequate emergency procedures (Reference 9).

d. Requested Information Item 2(d) - Flood Protection System/Barrier Effectiveness Discuss the effectiveness of flood protection systems and exterior, incorporated, and temporary flood barriers.Discuss how these systems and barrierswere evaluated using the acceptance criteriadeveloped as part of Requested Information Item 1.h [in Enclosure 4 of the March 12, 2012, 50.54(f) letter]

Section 6 of NEI 12-07 defines 'acceptance' as:

"Flood protection features are considered acceptable if no conditions adverse to quality were identified during walkdowns, verification activities, or program reviews as determined by the licensee's Corrective Action Program. Conditions adverse to quality are those that prevent the flood protection feature from performing its credited function during a design basis external flooding event and are 'deficiencies' Deficiencies must be reported to the NRC in the response to the 50.54(f) letter."

As indicated in Section 3d, inspection guidance was used as included in NEI 12-07 (Reference 2). All observations that could not be immediately judged as acceptable were entered into the Corrective Action Program (CAP) for evaluation.

The purpose of the walkdowns performed in response to the NRC Request for Information regarding NTTF Recommendation 2.3, is to verify conformance with FCS's current licensing basis. The adequacy of the current licensing basis will be addressed in response to Recommendation 2.1.

Acceptance criteria for visual inspections performed during the walkdowns was used as included in NEI 12-07 (Reference 2) to insure that any conditions adverse to quality were identified. Considerations taken into account when flood protection features were reviewed included the following:

Flood protection configuration is in accordance with design drawings and the station's current licensing basis.

Visual inspection did not identify any material degradation. A detailed listing of acceptance criteria for visual inspections based upon NEI 12-07 (Reference 2) was available to the

-walkdown-team during performance of the walkdowns.

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NTTF Recommendation 2.3 (Walkdowns): Flooding Fort Calhoun Station Revision 0

When applicable, PMs or periodic inspections are in place, within their required periodicity, and of adequate scope.

No topography changes, including security barrier installations, adversely affect the site drainage.

Walkdowns were conducted to verify that flood protection systems and exterior, incorporated, and temporary flood barriers credited for keeping water out of safety-related areas are in good condition.

Flood protection features inspected at FCS (see Attachment A) also include flood doors, removable metal barriers providing flood protection for the Auxiliary Building and the Intake structure, and the associated tools and equipment required to install these barriers. An outdoor walkdown to identify topography changes was conducted and documented in the NEI 12-07 Walkdown Record Form. The visual inspection of the site and the review of the grade elevations shown on the site topographic map confirmed that no topography changes, added structures or security barriers affected site drainage as described in the CLB. Whether conduits from manholes or cable vaults could provide a path for ground water or rain water to enter safety related buildings was considered relative to the walkdown scope.

When conduits from manholes/cable vaults are routed to the safety related buildings, water sealed (Flood Protected) penetrations are provided. In a few cases there are entering conduits that turn up and terminate above grade level such that no path for water is provided. The walkdown scope included inspections of the external conduit seals. Internal conduit seals could not be visually inspected but are provided by design. Evidence of groundwater/rainwater leakage through conduits into safety related buildings at FCS was not identified during the walkdowns. Conduits at FCS do not provide a path for ground water or rain water to enter safety related buildings.

The walkdowns, procedure walk-through and document reviews verify that flood protection features incorporated in the FCS design provide effective barriers for keeping external flooding from reaching safety-related systems and equipment. The walkdowns, procedure walk-through, and document reviews did, however, result in some observations that were entered into the corrective action program (CAP) for disposition.

e. Requested Information Item 2(e) - Implementation of Walkdown Process Present information related to the implementation of the walkdown process (e.g., details of selection of the walkdown team and procedures) using the documentation template discussed in Requested Information Item 1.j [in Enclosure 4 of the March 12, 2012, 50.54(f) letter], including actions taken in response to the peer review.

Station walkdowns were implemented in accordance with the guidelines provided in NEI 12-07 (Reference 2). The FCS walkdown team included four Sargent & Lundy employees as well as one FCS Operator and the FCS Lead Responsible Engineer for flooding issues. All team members are familiar with the station licensing basis relative to external flooding, were badged at FCS and completed both NANTeL based training and OPPD's specific training on implementation of the walkdowns in accordance with NEI 12-07 guidelines. The Sargent & Lundy team consisted of four engineering and design support personnel (Mechanical/Structural/Electrical) familiar with Fort Calhoun Station. At least two team members performed all visual inspections. Walkdown results were documented using the NEI 12-07 recommended form. Walkdown packages, one for each flooding feature, where prepared in advance and included the NEI 12-07 walkdown form with Parts A and B already completed as well as reference drawings and documentation. The remaining parts of the walkdown forms were finalized after the Page 11

NTTF Recommendation 2.3 (Walkdowns): Flooding Fort Calhoun Station Revision 0 feature walkdown was completed, and the identification of any item requiring further action was entered into corrective action program (CAP).

f. Requested Information Item 2(f) - Findings and Corrective Actions Taken/Planned Results of the walkdown including key findings and identified degraded, non-conforming, or unanalyzed conditions. Include a detailed description of the actions taken or planned to address these conditions using the guidance in Regulatory Issues Summary 2005-20, Rev 1, Revision to NRC Inspection Manual Part 9900 Technical Guidance, "OperabilityConditions Adverse to Quality or Safety," including entering the condition in the corrective action program.

The walkdown scope was developed to confirm that flood protection features credited in the current licensing basis are acceptable and capable of performing their credited flood protection functions. For Fort Calhoun Station (FCS) the scope primarily consisted of visual inspections of flood protection systems and exterior, incorporated, and temporary flood barriers. In addition, an outdoor walkdown was conducted to confirm surface drainage provisions have not been impacted by changes to topography, such as might result from installation of new security barriers. Inspections of credited walkdown features were performed by the walkdown team following the guidance provided in NEI 12-07 and were documented in walkdown packages using the NEI 12-07 walkdown forms. Walkdown record forms are retained onsite in accordance with plant procedures. Where degraded, non-conforming or unanalyzed conditions were identified, these findings were documented and entered into the station corrective action program (CAP).

The inspections of flood protection features verified that credited flood barriers are in place and no deficiencies were identified that render these features incapable of performing their intended flood protection function. However, some CRs noting identified discrepancies were generated and entered into the CAP. These have been addressed and are not deficiencies as defined in NEI 12-07. None of the issues identified during the walkdowns and documented in the CRs resulted in an operability concern.

A total of 14 CRs were generated in the process of performing the walkdowns. These are listed in Table 2.

Observations Not Immediately Judged As Acceptable Several CRs were generated to document some of the wall cracks and stains and signs of past water leakage observed during the walkdown. These CRs are listed in Table 2.

Observations Designated through CAP as Deficient None, Observations Not Evaluated for Deficiencies in CAP None, Restricted Access Area During this walkdown access to sixty four (64) flooding features (penetrations and walls) was restricted due to ongoing construction activities, or because access to these penetrations requires additional maintenance support. Approximately 38 of these penetrations (associated with Manhole 31) are being modified per EC 54662 to install upgraded conduit supports and new conduit seals to protect equipment from water intrusion from Manhole 31 via conduits. The remaining penetrations and walls are located in the Intake Structure and Auxiliary Building.

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NTTF Recommendation 2.3 (Walkdowns): Flooding Fort Calhoun Station Revision 0 Inspections of these barriers will be conducted upon availability of required maintenance support and completion of construction activities which will allow access to these barriers. These inspections will be completed by March 31, 2013.

Inaccessible Area The exterior Auxiliary Building concrete wall in Room 27 is covered by a metal plate and is inaccessible.

There is reasonable assurance that the feature is available and will perform the external flood protection for the full duration of the flood condition based on inspection of accessible areas of the exterior Auxiliary Building concrete wall. No signs of water leakage at the bottom of the plate where it mated up with the floor were observed in this room during the 2011 flood.

The exterior Auxiliary Building concrete wall in Room 8 and 17 is inaccessible due no reasonable means of physical access to these rooms. These rooms are not surveyed and the radiation level in the rooms is unknown. There is reasonable assurance that this feature is also available and will perform the external flood protection for the full duration of the flood condition based on inspection of accessible areas of the exterior Auxiliary Building concrete wall and that no leakage of water was observed from these rooms during the 2011 flood.

g. Requested Information Item 2(g) - Cliff -Edge Effects and Available Physical Margin Document any cliff-edge effects identified and the associated basis. Indicate those that were entered into the corrective action program.Also include a detailed description of the actions taken or planned to address these effects.

Cliff-edge effects were defined in the NTTF Report (Reference 5) as "the safety consequences of a flooding event may increase sharply with a small increase in the flooding level". As indicated in Section 3.12 of NEI 12-07 (Reference 2), the NRC is no longer expecting the Recommendation 2.3: Flooding Walkdowns to include an evaluation of cliff-edge effects. The NRC is now differentiating between cliff-edge effects, which are addressed in Enclosure 2 of Reference 3, and Available Physical Margin (APM).

As indicated in Section 3.13 of NEI 12-07 (Reference 2), APM describes the flood margin available for applicable flood protection features at a site (not all flood protection features have APMs). The APM for each applicable flood protection feature is the difference between licensing basis flood height and the flood height at which water could affect an SSC important to safety.

APM information was collected by OPPD to primarilysupport the response to Enclosure 2 of Reference 3 and, as such, is not included in this report. APM determinations did not involve calculating cliff-edge effects (i.e. the safety consequences). During the Integrated Assessment (see Enclosure 2 of Reference 3), the cliff-edge effects and the associated safety risks will be evaluated using the APMs and other information, such as the specific SSCs that are subjected to flooding and the potential availability of other systems to mitigate the risk. Furthermore, observations of 'small margin and significant consequences' were entered into the CAP for furtherevaluation.

h. Requested Information Item 2(h) - Planned/Newly-Installed Flood Protection Enhancements Describe any other planned or newly installed flood protection systems or flood mitigation measures including flood barriers that further enhance the flood protection. Identify results and any subsequent actions taken in response to the peer review.

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NTTF Recommendation 2.3 (Walkdowns): Flooding Fort Calhoun Station Revision 0 To further enhance FCS's flood protection program, OPPD has written CR 2012-16901 to develop and implement a procedure for periodic surveillance/maintenance of flood protection penetrations that are not already covered by such a program. The flood protection penetrations that also serve as fire protection barriers are already covered by the station's surveillance test program.

FCS is also in the process of installing wireless level measurement devices in manholes containing safety related cables. Installing the new level instrumentation will provide a reliable way to monitor the level of water in the manholes. It will also provide a tool for the plant to observe the pattern of water inleakage into manholes.

EC 55394 proposes to revise AOP-01 to provide Raw Water Pump intake cell level control during flooding conditions from (current) five sluice gates closed with the sixth sluice gate pre-positioned with a small opening to (new) all sluice gates closed and control level by operating 4 manual valves. The proposed configuration allows for better adjustment of flow and control of the intake cell level throughout the duration of the flood because the new valves are accessible from inside the intake structure, thus ensuring that the Raw Water Pumps remain available during a flood.

5. CONCLUSIONS Inspections of flood protection features identified no deficiencies that would render these features incapable of performing their intended function. All CRs entered into the CAP have been evaluated and there are no deficiencies. A reasonable simulation was not conducted. In place of the simulations the verifications completed as part of the process of installing new flood barriers in March 2011 and the barrier installation during the flood of summer 2011 at FCS were used to demonstrate that the applicable FCS flood protection procedure can be performed successfully. No other changes were determined necessary as a result of the flood walkdowns at FCS.

Visual inspection of the sluice gates in the Intake structure, which are active flood protection components within the walkdown scope, was not performed because they are located under water. However, these features are acceptable based on the fact that they are used during normal operation and are covered by the station's preventive maintenance program that periodically checks their integrity and function.

No operability issues were identified and no degraded, non-conforming or unanalyzed conditions require performance of additional actions.

Table 1 provides a summary of the number and type of features included in the walkdown scope.

Table 2 provides the list of the CRs generated and entered into the station corrective action program (CAP) as a result of the walkdown. None of these CRs resulted in an operability concern and none are reportable deficiencies.

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NTTF Recommendation 2.3 (Walkdowns): Flooding Fort Calhoun Station Revision 0 Table 1: Features Included in the Walkdown Scope Type # of Visual 4 of Simple # of Complex # of Drills or Inspections Simulations Simulations Exercises Incorporated/Exterior Passive 388 0 0 0 Incorporated/Exterior Active 14 0 0 0 Temporary Passive 20 0 0 0 Procedure Walk Through 3 0 0 0 Temporary Active 0 0 0 0 Totals 425 0 0 0 Table 2: CRs Generated in CAP CR Description Number 2012- During NRC Inspection of Near Term Task Force Recommendation 2.3 Flooding Walkdowns conducted per TI 14265 2515/187, the NRC inspector asked for the reason why the Intake Structure Sluice gates CW-14A/B/C/D/E/F were not included in the scope FCS flooding walkdown per NEI 12-07. In response to this question, the flood barriers included in the scope were reviewed and it was determined that the sluice gates should have been included in the scope and evaluated per NEI 12-07.

2012- Flooding walkdowns conducted per Fukushima NTTF 2.3 and NEI 12-07 state that "components with an active 15194 function can be assumed to function properly if included in a routine PM or surveillance program and the testing is performed under the program is acceptable". VD-681 and VD-682 were installed under EC 50514 and they serve to prevent flooding of the switchgear rooms during a design basis flood. The valves are not included in the preventive maintenance program, thus their operation during a flood cannot be assured. The valves are cycled on a quarterly basis as part of the Fire Protection drain valve flush procedure, OP-PM-FP-1000.

2012- While performing flooding walkdowns for the NTTF 2.3 in the Auxiliary Building, contract engineers found 14579 cracking in excess of 0.04" on the South wall adjacent to the SIRWT. While this wall is not an exterior wall and is not subject to exterior flooding inspection per NEI 12-07, this is a condition that may require additional engineering evaluation.

2012- While performing flooding walkdowns for the NTTF 2.3 in the Auxiliary Building, contract engineers found 14595 cracking in excess of 0.04" on the South wall. This wall is an exterior wall and is subject to exterior flooding inspection per NEI 12-07, thus this is a condition that requires additional engineering evaluation to determine if the wall can perform its design basis function.

2012- While performing flooding walkdowns for the NTTF 2.3 in Room 25 of the Auxiliary Building, contract engineers 14787 found a vent line off the SIRWT which has a flanged connection. The flanged connection is right above fire barrier 25-F-2 and is below the flood level during a design basis flood. Although the flange has a rubber gasket, there is no documentation that it is capable of providing a tight enough connection to prevent flood water leakage into the SIRWT. This connection needs to be evaluated and determine if it is an adequate flood penetration.

Page 15

NTTF Recommendation 2.3 (Walkdowns): Flooding Fort Calhoun Station Revision 0 CR Description Number 2012- While performing flooding walkdowns for the Fukushima NTTF 2.3, contract engineers observed stains and signs of past leakage around the drain line coming from the Railroad Bay/Room 25 into Room 24A. During a design basis flood, the drain line is isolated at the downstream valve WD-250, thus water will back up and leak if drain is not tight.

2012- While performing flooding walkdowns for the NTTF 2.3 in Room 19 of Auxiliary Building, contract engineers 14256 observed stains and rust around flood penetration 19-N-01, on the North wall, which may be indicative of past leakage around the penetration.

2012- While performing flooding walkdowns for the NTTF 2.3 in the Intake Structure, contract engineers found 142617 cracking in excess of 0.04" on the West wall. Evaluation of the capability of this structure to perform its design basis function is required.

2012- While performing flooding walkdowns for the NTTF 2.3 in the Auxiliary Building, contract engineers found 14278 cracking in excess of 0.04" on and around a plugged penetration on the west wall of Corridor 4. Evaluation of the capability of this flooding barrier to perform its design basis function is required. Photos of the observed cracks are attached for reference. Leakage from this wall was also identified during the 2011 Flood under CR 2011-5605, but no resolution of the issue can be found.

2012- Guidelines for Performing Verification Walkdowns of Plant Flood Protection Features conducted (NEI 12-07) 16874 states that "components with an active function can be assumed to function properly if included in a routine PM or surveillance program and the testing is performed under the program is acceptable". SD-127 and SD-128 were installed under EC 52290. WD-1303 was installed under EC 52184. Both ECs were developed in response to the 2011 FCS flooding and the valves serve as flood barriers. The ECs require that a PM be developed to inspect and cycle the valves every 5 years, however the ECs are not closed and new PMs are not prepared and made active. The CR is written to document the findings of the flooding walkdowns and to ensure that the PMs are developed and implemented as required by the ECs to satisfy the requirements of NEI 12-07.

2012- Guidelines for Performing Verification Walkdowns of Plant Flood Protection Features (NEI 12-07) states that 16884 "components with an active function can be assumed to function properly if included in a routine PM or surveillance program and the testing is performed under the program is acceptable". WD-250 is a normally locked open valve for the Railroad Area Sump Isolation. The valve is designated as a Flood Hazard component and AOP-1 requires that it be closed in case of a flood. There are no PMs associated with this valve that would ensure its functionality. The CR is written to document the findings of the flooding walkdowns and to ensure that a PM is developed and implemented as required by NEI 12-07.

2012- Guidelines for Performing Verification Walkdowns of Plant Flood Protection Features (NEI 12-07)states that 16891 components with an active function can be assumed to function properly if included in a routine PM or surveillance program and the testing is performed under the program is acceptable". WD-1216, WD-1217, WD-1218 and WD-1219 are Radwaste building Sump pump isolation valves designated as a Flood Hazard components and AOP-1 requires that they be closed in case of a flood. There are no PMs associated with these valves to ensure their functionality. The CR is written to document the findings of the flooding walkdowns and to ensure that a PM is developed and implemented as required by NEI 12-07.

2012- As a result of the NRC required Flooding Walkdown performed by OPPD, it was determined that some flood 16901 protection features are not included in a periodic test, monitoring or inspection program to ensure that their functionality is adequately maintained. Specifically, the flood protection penetrations that do not serve as a fire barrier are not covered by such a program. In accordance with the NRC endorsed NEI 12-07, Guidelines for Performing Verification Walkdowns of Plant Flood Protection Features, these flood protection penetrations are to be included in a periodic test, monitoring or inspection program to ensure that their functionality is adequately maintained. These flood protection penetrations are listed in the attachment.

2012- Approximately a 2' long crack was found on the floor (greater than .04) at El. 993'-6". A crater in the slab the 17040 size of approximately 2" to 3" in diameter and about 1" deep with loose aggregate inside is located on the floor at El. 974'-8" between Column Row 103 & 104 along Col. Row AA, 13' north of column row 103 and 6' to 7' east of the west wall. Gaps between the floor slab & the bottom of the wall observed around the 3 sides (east, south & west sides) of the room in several places. This CR is written per the requirements of NEI-12-07 acceptance criteria, which states that cracks in excess of 0.04"require evaluation.

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NTTF Recommendation 2.3 (Walkdowns): Flooding Fort Calhoun Station Revision 0

6. REFERENCES

1. Omaha Public Power District Letter No.: LIC-12-0078, dated June 8, 2012 to U.S. Nuclear Regulatory Commission, "OPPD 90-Day Response to NRC Request for Information Pursuant to 10 CFR 50.54(f)

Regarding Recommendations 2.1 and 2.3 (Flooding), of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident"

2. Nuclear Energy Institute (NEI), Report 12-07 [Rev 0-A]. Guidelines for Performing Verification Walkdowns of PlantProtection Features. May 2012 [NRC endorsed May 31, 2012; updated and re-issued June 18, 2012].

3. Letter from NRC (E. J. Leeds & M. R. Johnson) to OPPD (D. J. Bannister), "Request for Information Pursuant to Title 10 of the Code of Federal Regulations 50.54(f) Regarding Recommendations 2.1, 2.3, and 9.3 of the Near-Term Task Force Review of Insights from the Fukushima Dai-lchi Accident,"

dated March 12, 2012 (ML12053A340) (NRC-12-0021)

4. Letter from NRC (E. J. Leeds) to OPPD (D. J. Bannister), "Prioritization of Response Due Dates For Request for Information Pursuant to Title 10 of the Code of Federal Regulations 50.54(f) Regarding Recommendations 2.1, 2.3, and 9.3, of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident," dated May 11,2012 (ML2097A509) (NRC-12-0048)

5. U.S. Nuclear Regulatory Commission. Recommendations for Enhancing Reactor Safety in the 21st Century, The Near Term Task Force Review of Insights from the Fukushima Dai-ichiAccident. July 12, 2011.

6. U.S. Nuclear Regulatory Commission. Operability Determinations & Functionality Assessments for Resolution of Degraded or Nonconforming Conditions Adverse to Quality or Safety. NRC Inspection Manual. Part 9900: Technical Guidance. Regulatory Issues Summary 2005-20, Revisions 1.

September 26, 2005

7. Fort Calhoun Station USAR

8. Letter from NRC (D. L. Skeen) to NEI (A. P. Heymer), "Endorsement of Nuclear Energy Institute (NEI) 12-07, Guidelinesfor Performing Verification Walkdowns of PlantFlood Protection Features," dated May 31,2012 (ML12144A142)

9. PLDBD-CS External Flooding, Rev. 1

7. ATTACHMENTS A. Flood Protection Features List, Fort Calhoun Station, dated 11/21/2012 Page 17

Attachment A - Flooding Walkdown Report Flood Protection Features List 11/21/2012 Fort Calhoun Station Item Feature ID/ Description Bldg./Area CLB Feature Room Other Description Feature/Barrier Type CLB Flood El.

Procedure No. Elevation (if any) At Feature 1 04-W-01 Abandoned FP Aux Bldg 998'-4" 4 - Basement Aux Abandon FP penetration-Grouted Incorporated or Exterior 1014 ft penetration-Grouted Building Control Area Passive (IEP) 2 0971-02 Water Tight Door to Aux Bldg 971'-0" 22 - East SI Pump Water Tight Door to Stressing Gallary Incorporated or Exterior 1014 ft Stressing GaIlary Room Active (IEA) 3 1013-04 Access Door from DG Aux Bldg 1013' 65 - Diesel Vent Room Access Door from DG Rooms to Temporary Passive (TP) 1014 ft Rooms to Equipment Equipment Hatch Room Hatch Room 4 10-N-P7 Chem Lab Drains to Aux Aux Bldg 999'-6" 10 - Monitor Tank Chem Lab Drains to Aux Building WD Incorporated or Exterior 1014 ft Building WD Room Passive (IEP) 5 19-E-01 Penetration Aux Bldg 1009'-8" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 6 19-E-02 Penetration Aux Bldg 10091-8" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 7 19-E-03 Penetration Aux Bldg 1009'-8" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 8 19-E-04 Penetration Aux Bldg 10091-8" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 9 19-E-05 Penetration Aux Bldg 10081-10" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 10 19-E-06 Penetration Aux Bldg 1008'-10" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 11 19-E-07 Penetration Aux Bldg 1008'-4" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 12 19-E-08 Penetration Aux Bldg 10081-10" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 13 19-E-09 Penetration Aux Bldg 1008'-10' 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP)

Page 1 of 34

Attachment A - Flooding Walkdown Report Flood Protection Features List !11121/2012 Fort Calhoun Station Item Feature ID/ Description Bldg./Area CLB Feature Room Other Description Feature/Barrier Type CLB Flood El.

Procedure No. Elevation (if any) At Feature 14 19-E-10 Penetration Aux Bldg 1008'-10" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 15 19-E-11 Penetration Aux Bldg 10081-10" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 16 19-E-12 Penetration Aux Bldg 10081-10" 19- Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 17 19-E-13 Penetration Aux Bldg 10081-10" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 18 19-E-14 Penetration Aux Bldg 1008'-2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 19 19-E-15 Penetration Aux Bldg 1008'-2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 20 19-E-16 Penetration Aux Bldg 1008'-2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 21 19-E-17 Penetration Aux Bldg 10081-2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 22 19-E-18 Penetration Aux Bldg 1008'-2" 19- Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 23 19-E-19 Penetration Aux Bldg 1008'-2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 24 19-E-20 Penetration Aux Bldg 1008'-2" 19- Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 25 19-E-21 Penetration Aux Bldg 1008'-2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 26 19-E-22 Penetration Aux Bldg 1008'-2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP)

Page 2 of 34

Attachment A - Flooding Walkdown Report Flood Protection Features List 11121/2012 Fort Calhoun Station Item Feature ID/ Description Bldg./Area CLB Feature Room Other Description Feature/Barrier Type CLB Flood El.

Procedure No. Elevation (if any) At Feature 27 19-E-23 Penetration Aux Bldg 1008'-4" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 28 19-E-24 Penetration Aux Bldg 1008'-4" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 29 19-E-25 Penetration Aux Bldg 1008'-4" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 30 19-E-26 Penetration Aux Bldg 1008'-10" 19- Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 31 19-E-27 Penetration Aux Bldg 1008'-8" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 32 19-E-28 Penetration Aux Bldg 10081-8" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 33 19-E-29 Penetration Aux Bldg 1008'-8' 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 34 19-E-30 Penetration Aux Bldg 1008'-8" 19- Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 35 19-E-31 Penetration Aux Bldg 1008'-8" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 36 19-E-32 Penetration Aux Bldg 10081-8" 19- Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 37 19-E-33 Penetration Aux Bldg 1008'-8" 19- Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 38 19-E-34 Penetration Aux Bldg 1008'-8" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 39 19-E-35 Penetration Aux Bldg 1008'-8" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP)

Page 3 of 34

Attachment A - Flooding Walkdown Report Flood Protection Features List 11/21/2012 Fort Calhoun Station Item Feature ID/ Description Bldg./Area CLB Feature Room Other Description Feature/Barrier Type CLB Flood El.

Procedure No. Elevation (if any) At Feature 40 19-E-36 Penetration Aux Bldg 1008'-0" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 41 19-E-37 Penetration Aux Bldg 1008'-0" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 42 19-E-38 Penetration Aux Bldg 10081-8' 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 43 19-E-39 Penetration Aux Bldg 10081-0" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 44 19-E-40 Penetration Aux Bldg 1008'-0" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive ((EP) 45 19-E-41 Penetration Aux Bldg 1008'-0" 19- Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 46 19-E-42 Penetration Aux Bldg 10081-0" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 47 19-E-43 Penetration Aux Bldg 1008'-0" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 48 19-E-44 Penetration Aux Bldg 1008'-0" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 49 19-E-45 Penetration Aux Bldg 1008'-8" 19- Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 50 19-E-46 Penetration Aux Bldg 10081-8" 19- Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 51 19-E-47 Penetration Aux Bldg 1008'-8" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 52 19-E-48 Penetration Aux Bldg 10081-8" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP)

Page 4 of 34

Attachment A - Flooding Walkdown Report Flood Protection Features List 11/21/2012 Fort Calhoun Station Item Feature ID/ Description Bldg./Area CLB Feature Room Other Description Feature/Barrier Type CLB Flood El.

Procedure No. Elevation (if any) At Feature 53 19-E-49 Penetration Aux Bldg 1008'-0" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 54 19-E-50 Penetration Aux Bldg 1008'-8" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 55 19-E-51 Penetration Aux Bldg 1009'-0" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 56 19-E-52 Penetration Aux Bldg 1008'-10" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 57 19-E-53 Penetration Aux Bldg 1008'-10" 19- Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 58 19-E-54 Penetration Aux Bldg 10091-0" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 59 19-E-55 Penetration Aux Bldg 1008'-8" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 60 19-E-57 Penetration Aux Bldg 10081-10" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 61 19-E-58 Penetration Aux Bldg 1008'-10" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 62 19-E-59 Penetration Aux Bldg 1008'-10" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 63 19-E-60 Penetration Aux Bldg 1008'-7" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 64 19-E-61 Penetration Aux Bldg 1009'-6" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 65 19-E-62 Penetration Aux Bldg 1008'-7" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP)

Page 5 of 34

Attachment A - Flooding Walkdown Report Flood Protection Features List 11/21/2012 Fort Calhoun Station Item Feature ID/ Description Bldg./Area CLB Feature Room Other Description Feature/Barrier Type CLB Flood El.

Procedure No. Elevation (if any) At Feature 66 19-E-63 Penetration Aux Bldg 1010'-2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 67 19-E-64 Penetration Aux Bldg 1009'-6" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 68 19-E-65 Penetration Aux Bldg 1009'-6" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 69 19-E-66 Penetration Aux Bldg 1009'-6" 19- Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 70 19-E-67 Penetration Aux Bldg 10081-8" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 71 19-E-68 Penetration Aux Bldg 10081-10' 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 72 19-E-69 Penetration Aux Bldg 1008'-10" 19- Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 73 19-E-70 Penetration Aux Bldg 10081-10" 19- Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 74 19-N-01 Penetration Aux Bldg 9991-0" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 75 19-S-59 Abandoned Service Aux Bldg 997'-2" 19 -Air Compressor Abandoned Service Water penetration Incorporated or Exterior 1014 ft Water penetration Room Passive (IEP) 76 19-S-60 Sewer Line Aux Bldg 997'-2" 19 - Air Compressor Sewer Line Incorporated or Exterior 1014 ft Room Passive (IEP) 77 19-S-61 Penetration Aux Bldg 996'-0" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 78 19-5-62 Penetration Aux Bldg 996-0" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP)

Page 6 of 34

Attachment A - Flooding Walkdown Report Flood Protection Features List 11/21/2012 Fort Calhoun Station Item Feature ID/ Description Bldg./Area CLB Feature Room Other Description Feature/Barrier Type CLB Flood El.

Procedure No. Elevation (if any) At Feature 79 19-S-E01 Penetration Aux Bldg 1008-10 1/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 80 19-S-E02 Penetration Aux Bldg 1008'-10 1/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 81 19-S-E03 Penetration Aux Bldg 1008'-10 1/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 82 19-S-E04 Penetration Aux Bldg 1008'-10 1/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 83 19-S-EOS Penetration Aux Bldg 1008'-3 1/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 84 19-S-E07 Penetration Aux Bldg 1008'-3 1/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 85 19-S-EO8 Penetration Aux Bldg 1008'-3 1/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 86 19-S-E09 Penetration Aux Bldg 1008'-3 1/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 87 19-S-E10 Penetration Aux Bldg 1008'-3 1/2" 19 -Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 88 19-S-Eli Penetration Aux Bldg 1008'-3 1/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 89 19-S-E13 Penetration Aux Bldg 1007'-8 1/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 90 19-S-E14 Penetration Aux Bldg 1007'-8 1/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 91 19-S-El5 Penetration Aux Bldg 1007'-8 1/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP)

Page 7 of 34

Attachment A - Flooding Walkdown Report Flood Protection Features List 11/21/2012 Fort Calhoun Station Item Feature ID/ Description Bldg./Area CLB Feature Room Other Description Feature/Barrier Type CLB Flood El.

Procedure No. Elevation (if any) At Feature 92 19-S-E16 Penetration Aux Bldg 1007'-8 1/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 93 19-S-E17 Penetration Aux Bldg 1007-8 1/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 94 19-S-E18 Penetration Aux Bldg 1007'-8 1/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 95 19-S-E19 Penetration Aux Bldg 1007'-8 1/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 96 19-S-E20 Penetration Aux Bldg 1007-8 1/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 97 19-S-E21 Penetration Aux Bldg 1008'-10 1/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 98 19-S-E22 Penetration Aux Bldg 1008'-3 1/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 99 19-S-E23 Penetration Aux Bldg 1008'-3 1/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 100 19-S-E24 Penetration Aux Bldg 1008'-10 1/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 101 19-S-E25 Penetration Aux Bldg 1008'-3 1/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 102 19-S-E26 Penetration Aux Bldg 1008'-3 1/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 103 19-S-E27 Penetration Aux Bldg 1008'-3 1/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 104 19-S-E28 Penetration Aux Bldg 1008'-3 1/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP)

Page 8 of 34

Attachment A - Flooding Walkdown Report Flood Protection Features List 11/21/2012 Fort Calhoun Station Item Feature ID/ Description Bldg./Area CLB Feature Room Other Description Feature/Barrier Type CLB Flood El.

Procedure No. Elevation (if any) At Feature 105 19-S-E29 Penetration Aux Bldg 1008'-3 1/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 106 19-S-E30 Penetration Aux Bldg 1008'-3 1/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 107 19-S-E31 Penetration Aux Bldg 1008'-3 1/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 108 19-S-E32 Penetration Aux Bldg 1008'-3 1/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 109 19-S-E34 Penetration Aux Bldg 1007-8 1/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 110 19-S-E35 Penetration Aux Bldg 1007'-8 1/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 111 19-S-E36 Penetration Aux Bldg 1007'-8 1/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 112 19-S-E37 Penetration Aux Bldg 1007-8 1/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 113 19-S-E38 Penetration Aux Bldg 1007'-8 1/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 114 19-S-E40 Penetration Aux Bldg 1007'-8 1/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 115 19-S-E41a Penetration Aux Bldg 1007'-8 1/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 116 19-S-E41b Penetration Aux Bldg 1008'-3 1/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 117 19-S-E42 Penetration Aux Bldg 1008'-3 1/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP)

Page 9 of 34

Attachment A - Flooding Walkdown Report Flood Protection Features List 11/21/2012 Fort Calhoun Station Item Feature ID/ Description Bldg./Area CLB Feature Room Other Description Feature/Barrier Type CLB Flood El.

Procedure No. Elevation (if any) At Feature 118 19-S-E42a Penetration Aux Bldg 1007-8 1/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 119 19-S-E43 Penetration Aux Bldg 1008'-3 1/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 120 19-S-E44 Penetration Aux Bldg 1008'-3 1/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 121 19-S-E45 Penetration Aux Bldg 1008'-3 1/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 122 19-S-E46 Penetration Aux Bldg 1008'-3 1/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 123 19-S-E47 Penetration Aux Bldg 1008'-3 1/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 124 19-S-E48b Penetration Aux Bldg 1008'-3 1/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 125 19-S-E49a Penetration Aux Bldg 1008'-3 1/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 126 19-S-E49b Penetration Aux Bldg 1007'-8 1/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 127 19-S-E50a Penetration Aux Bldg 1008'-3 2/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 128 19-S-E50b Penetration Aux Bldg 1007'-8 1/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 129 19-S-E51 Penetration Aux Bldg 1007-8 1/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 130 19-S-E52 Penetration Aux Bldg 1007'-8 1/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP)

Page 10 of 34

Attachment A - Flooding Walkdown Report Flood Protection Features List 11/21/2012 Fort Calhoun Station Item Feature ID/ Description Bldg./Area CLB Feature Room Other Description Feature/Barrier Type CLB Flood El.

Procedure No. Elevation (if any) At Feature 131 19-S-ES3b Penetration Aux Bldg 1007-8 1/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 132 19-S-E54 Penetration Aux Bldg 1007'-8 1/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 133 19-S-E55 Penetration Aux Bldg 1007'-8 1/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 134 19-S-ES6 Penetration Aux Bldg 1007'-8 1/2" 19 - Air Compressor Incorporated or Exterior 1014 ft Room Passive (IEP) 135 22-S-01 Penetration Aux Bldg 983'-3" 22 - East SI Pump Incorporated or Exterior 1014 ft Room Passive (IEP) 136 24a-S-01 Penetration Aux Bldg Rm 1001'-0" 2- SIRWT Unassigned Capped pipe sleeve Incorporated or Exterior 1014 ft 24a Passive (IEP) 137 25-F-01 Penetration Aux Bldg RR 1007'-0" 24- Fuel Transfer SIRWT Vent Rm 2 to Rm 25 Incorporated or Exterior 1014 ft Bay I Canal Pump Room Passive (IEP) 138 25-F-02 Penetration Aux Bldg RR 1007'-0" 24 - Fuel Transfer SIRW-T Vent Rm 2 to Rm 25 Incorporated or Exterior 1014 ft Bay Canal Pump Room Passive (IEP) 139 25-F-03 Penetration Aux Bldg 1007-0" Room 25 Incorporated or Exterior 1014 ft Passive (IEP) 140 25-F-04 Penetration Aux Bldg 1007'-0" Room 25 Incorporated or Exterior 1014 ft Passive (IEP) 141 26-N-38 Penetration Aux Bldg 1017'-8" Room 26 Not a flood penetration Incorporated or Exterior 1014 ft Passive (IEP) 142 27-W-06 Penetration Aux Bldg 1007'-0" 27 - Drumming Area aux building penetration for ATCOR Incorporated or Exterior 1014 ft (Sealed) Passive (IEP) 143 29-W-01 Penetration Rad Waste 1012'-9 1/2" 29 - VCT Room Incorporated or Exterior 1014 ft Passive (IEP)

Page 11 of 34

Attachment A - Flooding Walkdown Report Flood Protection Features List 11/21/2012 Fort Calhoun Station Item Feature ID/ Description Bldg./Area CLB Feature Room Other Description Feature/Barrier Type CLB Flood El.

Procedure No. Elevation (if any) At Feature 144 29-W-02 Penetration Rad Waste 1012'-9 1/2" 29 - VCT Room Incorporated or Exterior 1014 ft Passive (IEP) 145 29-W-04 Penetration Rad Waste 1011'-6" 29 - VCT Room Incorporated or Exterior 1014 ft Passive (IEP) 146 29-W-05 Penetration Rad Waste 1010'-0" 29 - VCT Room Incorporated or Exterior 1014 ft Passive (IEP) 147 29-W-06 Penetration Rad Waste 1010'-0" 29 - VCT Room Incorporated or Exterior 1014 ft Passive (IEP) 148 29-W-09 Penetration Rad Waste 1011'-6" 29 - VCT Room Incorporated or Exterior 1014 ft Passive (IEP) 149 29-W-10 Penetration Rad Waste 1011'-2" 29 - VCT Room Incorporated or Exterior 1014 ft Passive (IEP) 150 29-W-11 Penetration Rad Waste 1011'-2" 29 - VCT Room Incorporated or Exterior 1014 ft Passive (IEP) 151 56E-S-03 Penetration Aux Bldg 1011'-8" 56E - Switchgear Incorporated or Exterior 1014 ft Room (East) Passive (IEP) 152 56E-S-04 Penetration Aux Bldg 10111-8" 56E - Switchgear Incorporated or Exterior 1014 ft Room (East) Passive (IEP) 153 56E-S-05 Penetration Aux Bldg 1011'-8" 56E - Switchgear Incorporated or Exterior 1014 ft Room (East) Passive (IEP) 154 56E-S-06 Penetration Aux Bldg 10111-8" 56E - Switchgear Incorporated or Exterior 1014 ft Room (East) Passive (IEP) 155 56E-S-07 Penetration Aux Bldg 10111-8" 56E - Switchgear Incorporated or Exterior 1014 ft Room (East) Passive (IEP) 156 56E-S-08 Penetration Aux Bldg 10111-8" 56E - Switchgear Incorporated or Exterior 1014 ft Room (East) Passive (IEP)

Page 12 of 34

Attachment A - Flooding Walkdown Report Flood Protection Features List 11/21/2012 Fort Calhoun Station Item Feature ID/ Description Bldg./Area CLB Feature Room Other Description Feature/Barrier Type CLB Flood El.

Procedure No. Elevation (if any) At Feature 157 56E-S-09 Penetration Aux Bldg 10111-8" 56E - Switchgear Incorporated or Exterior 1014 ft Room (East) Passive (IEP) 158 56E-S-10 Penetration Aux Bldg 1011'-8" 56E - Switchgear Incorporated or Exterior 1014 ft Room (East) Passive (IEP) 159 56E-S-11 Penetration Aux Bldg 10111-8" 56E - Switchgear Incorporated or Exterior 1014 ft Room (East) Passive (IEP) 160 56E-S-12 Penetration Aux Bldg 1011'-81" S6E - Switchgear Incorporated or Exterior 1014 ft Room (East) Passive (IEP) 161 56E-S-13 Penetration Aux Bldg 10111-8" 56E - Switchgear Incorporated or Exterior 1014 ft Room (East) Passive (IEP) 162 $6E-S-14 Penetration Aux Bldg 1011'-8" 56E - Switchgear Incorporated or Exterior 1014 ft Room (East) Passive (IEP) 163 56E-S-15 Penetration Aux Bldg 1011'-8" 56E - Switchgear Incorporated or Exterior 1014 ft Room (East) Passive (IEP) 164 56E-S-16 Penetration Aux Bldg 1011'-8" 56E - Switchgear Incorporated or Exterior 1014 ft Room (East) Passive (IEP) 165 56E-S-17 Penetration Aux Bldg 10111-81" 56E - Switchgear Incorporated or Exterior 1014 ft Room (East) Passive (IEP) 166 56E-S-18 Penetration Aux Bldg 1011'-8" 56E - Switchgear Incorporated or Exterior 1014 ft Room (East) Passive (IEP) 167 56E-S-19 Penetration Aux Bldg 1014'-0" S6E - Switchgear Incorporated or Exterior 1014 ft Room (East) Passive (IEP) 168 56E-S-20 Penetration Aux Bldg 1014'-0" 56E - Switchgear Incorporated or Exterior 1014 ft Room (East) Passive (IEP) 169 56E-S-21 Penetration Aux Bldg 1014'-0" 56E - Switchgear Incorporated or Exterior 1014 ft Room (East) Passive (IEP)

Page 13 of 34

Attachment A - Flooding Walkdown Report Flood Protection Features List 11/21/2012 Fort Calhoun Station Item Feature ID/ Description Bldg./Area CLB Feature Room Other Description Feature/Barrier Type CLB Flood El.

Procedure No. Elevation (if any) At Feature 170 56E-S-22 Penetration Aux Bldg 1014'-0" 56E - Switchgear Incorporated or Exterior 1014 ft Room (East) Passive (IEP) 171 56E-S-23 Penetration Aux Bldg 1014'-0" 56E - Switchgear Incorporated or Exterior 1014 ft Room (East) Passive (IEP) 172 56E-S-24 Penetration Aux Bldg 1014'-0" 56E - Switchgear Incorporated or Exterior 1014 ft Room (East) Passive (IEP) 173 56E-S-25 Penetration Aux Bldg 1014'-0" 56E - Switchgear Incorporated or Exterior 1014 ft Room (East) Passive (IEP) 174 56E-5-26 Penetration Aux Bldg 1014'-0" 56E - Switchgear Incorporated or Exterior 1014 ft Room (East) Passive (IEP) 175 56E-S-27 Penetration Aux Bldg 1013'-5" 56E - Switchgear Incorporated or Exterior 1014 ft Room (East) Passive (IEP) 176 56E-S-28 Penetration Aux Bldg 1013'-5" 56E - Switchgear Incorporated or Exterior 1014 ft Room (East) Passive (IEP) 177 56E-S-29 Penetration Aux Bldg 1013'-5" 56E - Switchgear Incorporated or Exterior 1014 ft Room (East) Passive (IEP) 178 56E-S-30 Penetration Aux Bldg 1013'-5" 56E - Switchgear Incorporated or Exterior 1014 ft Room (East) Passive (IEP) 179 56E-S-31 Penetration Aux Bldg 1013'-5" 56E - Switchgear Incorporated or Exterior 1014 ft Room (East) Passive (IEP) 180 56E-S-32 Penetration Aux Bldg 1013'-5" 56E - Switchgear Incorporated or Exterior 1014 ft Room (East) Passive (IEP) 181 56E-S-33 Penetration Aux Bldg 1013'-5" 56E - Switchgear Incorporated or Exterior 1014 ft Room (East) Passive (IEP) 182 56E-S-34 Penetration Aux Bldg 1013'-5" 56E - Switchgear Incorporated or Exterior 1014 ft Room (East) Passive (IEP)

Page 14 of 34

Attachment A - Flooding Walkdown Report Flood Protection Features List 11/21/2012 Fort Calhoun Station Item Feature ID/ Description Bldg./Area CLB Feature Room Other Description Feature/Barrier Type CLB Flood El.

Procedure No. Elevation (if any) At Feature 183 56E-S-35 Penetration Aux Bldg 1012'-10" 56E - Switchgear Incorporated or Exterior 1014 ft Room (East) Passive (IEP) 184 56E-5-36 Penetration Aux Bldg 1012'-10" 56E - Switchgear Incorporated or Exterior 1014 ft Room (East) Passive (IEP) 185 56E-S-37 Penetration Aux Bldg 1012'-10" 56E - Switchgear Incorporated or Exterior 1014 ft Room (East) Passive (IEP) 186 56E-S-38 Penetration Aux Bldg 1012'-10" 56E - Switchgear Incorporated or Exterior 1014 ft Room (East) Passive (IEP) 187 56E-S-39 Penetration Aux Bldg 1012'-10" 56E - Switchgear Incorporated or Exterior 1014 ft Room (East) Passive (IEP) 188 56E-S-40 Penetration Aux Bldg 1012'-10" 56E - Switchgear Incorporated or Exterior 1014 ft Room (East) Passive (IEP) 189 56E-S-41 Penetration Aux Bldg 1012'-10" 56E - Switchgear Incorporated or Exterior 1014 ft Room (East) Passive (IEP) 190 56E-S-42 Penetration Aux Bldg 1012'-10" 56E - Switchgear Incorporated or Exterior 1014 ft Room (East) Passive (IEP) 191 56E-S-43 Penetration Aux Bldg 1012'-3" 56E - Switchgear Incorporated or Exterior 1014 ft Room (East) Passive (IEP) 192 56E-S-44 Penetration Aux Bldg 1012'-3" 56E - Switchgear Incorporated or Exterior 1014 ft Room (East) Passive (IEP) 193 56E-S-45 Penetration Aux Bldg 1012'-3" 56E - Switchgear incorporated or Exterior 1014 ft Room (East) Passive (IEP) 194 56E-S-46 Penetration Aux Bldg 1012'-3" 56E - Switchgear Incorporated or Exterior 1014 ft Room (East) Passive (IEP) 195 56E-5-47 Penetration Aux Bldg 1012'-3" 56E - Switchgear Incorporated or Exterior 1014 ft Room (East) Passive (IEP)

Page 15 of 34

Attachment A - Flooding Walkdown Report Flood Protection Features List 11/21/2012 Fort Calhoun Station Item Feature ID/ Description Bldg./Area CLB Feature Room Other Description Feature/Barrier Type CLB Flood El.

Procedure No. Elevation (if any) At Feature 196 56E-S-48 Penetration Aux Bldg 1012'-3" 56E - Switchgear Incorporated or Exterior 1014 ft Room (East) Passive (IEP) 197 56E-S-49 Penetration Aux Bldg 1012'-3" 56E - Switchgear Incorporated or Exterior 1014 ft Room (East) Passive (IEP) 198 56E-S-50 Penetration Aux Bldg 1012'-3" 56E - Switchgear Incorporated or Exterior 1014 ft Room (East) Passive (IEP) 199 56E-S-51 Penetration Aux Bldg 1011'-8" 56E - Switchgear Incorporated or Exterior 1014 ft Room (East) Passive (IEP) 200 56E-S-52 Penetration Aux Bldg 1011'-8" 56E - Switchgear Incorporated or Exterior 1014 ft Room (East) Passive (IEP) 201 56E-S-53 Penetration Aux Bldg 1011'-8" 56E - Switchgear Incorporated or Exterior 1014 ft Room (East) Passive (IEP) 202 56E-S-54 Penetration Aux Bldg 10111-8" 56E - Switchgear Incorporated or Exterior 1014 ft Room (East) Passive (IEP) 203 56E-S-55 Penetration Aux Bldg 1011'-8" 56E - Switchgear Incorporated or Exterior 1014 ft Room (East) Passive (IEP) 204 56E-S-56 Penetration Aux Bldg 10111-8" 56E - Switchgear Incorporated or Exterior 1014 ft Room (East) Passive (IEP) 205 56E-S-57 Penetration Aux Bldg 10111-8' 56E - Switchgear Incorporated or Exterior 1014 ft Room (East) Passive (IEP) 206 56E-S-58 Penetration Aux Bldg 1011'-8" 56E - Switchgear incorporated or Exterior 1014 ft Room (East) Passive (IEP) 207 63-S-01 Penetration Aux Bldg 1008' 6" 63 - D1 Room Incorporated or Exterior 1014 ft Passive (IEP) 208 63-S-05 Penetration Aux Bldg 1007' 6" 63 - Dl Room Incorporated or Exterior 1014 ft Passive (IEP)

Page 16 of 34

Attachment A - Flooding Walkdown Report Flood Protection Features List 11/21/2012 Fort Calhoun Station Item Feature ID/ Description Bldg./Area CLB Feature Room Other Description Feature/Barrier Type CLB Flood El.

Procedure No. Elevation (if any) At Feature 209 63-S-06 Penetration Aux Bldg 1007' 8" 63 - D1 Room Incorporated or Exterior 1014 ft Passive (IEP) 210 63-S-07 Penetration Aux Bldg 1013' 63 - D1 Room Incorporated or Exterior 1014 ft Passive (IEP) 211 AC-10A/B/C/D/ Raw Water Pump IS- Intake 999'-4' IS- Intake Structure Incorporated or Exterior 1014 ft Structure Active (lEA) 212 AE-13A Mechanical Penetration IS- Intake 1009, 0" IS- Intake Structure Incorporated or Exterior 1014 ft Structure Passive (IEP) 213 AE-13B Mechanical Penetration IS- Intake 1009' 0" IS- Intake Structure Incorporated or Exterior 1014 ft Structure Passive (IEP) 214 AE-16 / IS-2 Flood barrier for South IS- Intake 1007'-6" IS- Intake Structure Temporary Passive (TP) 1014 ft west intake structure Structure door (IS-1) 215 AE-17/ Flood barrier for South IS-Intake 1007'-6" IS- Intake Structure Flood barrier for South East intake Temporary Passive (TP) 1014 ft IS-2 East intake structure door Structure structure door (IS-2)

(IS-2) 216 AE-18/ Flood barrier for North IS-Intake 1007'-6" IS- Intake Structure Flood barrier for North East intake Temporary Passive (TP) 1014 ft IS-3 East intake structure door Structure structure door (IS-3)

(IS-3) 217 AE-19 / IS-4 Flood barrier for North IS-Intake 1004'-6" IS - Intake Structure Temporary Passive (TP) 1014 ft West intake structure Structure door (IS-4) 218 AE-20/ IS-5 Flood barrier for intake IS-Intake 1004'-6" IS- Intake Structure Temporary Passive (TP) 1014 ft structure truck dockdoor Structure (IS-5) 219 AE-21/ Screen Wash Trough IS-Intake 1007'-6" IS- Intake Structure Screen Wash Trough Discharge Temporary Passive (TP) 1014 ft IS-F-32 Discharge Penetration Structure Penetration 220 AE-22/ Roll-up Door to Rad Aux Bldg 1007-0" 26 - Aux Building Roll-up Door to Rad Waste Building Temporary Passive (TP) 1014 ft 1007-01A/B Waste Building Main Floor Corridor 221 AE-23/ Door From Corridor 26 to Aux Bldg 1007' 26 - Aux Building Door From Corridor 26 to Chem Lab Temporary Passive (TP) 1014 ft 1007-09 Chem Lab Main Floor Corridor Page 17 of 34

Attachment A - Flooding Walkdown Report Flood Protection Features List 11/21/2012 Fort Calhoun Station Item Feature ID/ Description Bldg./Area CLB Feature Room Other Description Feature/Barrier Type CLB Flood El.

Procedure No. Elevation (if any) At Feature 222 AE-24/ Aux Building Access Door Aux Bldg 1007' 52 - Corridor to Aux Aux Building Access Door Temporary Passive (TP) 1014 ft 1007-19 Bldg Locker Room 223 AE-25/ Door To Corridor 53 Aux Bldg 1011, 53 - Corridor to Door To Corridor 53 Temporary Passive (TP) 1014 ft 1011-01 Switchgear Room 224 AE-26/ East Door to Battery Aux Bldg 1011' 54 - East Battery East Door to Battery Room Temporary Passive (TP) 1014 ft 1011-02 Room Room 225 AE-27/ North East Door to Aux Bldg 1011' 56E - Switchgear North East Door to Switchgear Room Temporary Passive (TP) 1014 ft 1011-03 Switchgear Room Room (East) 226 AE-28/ South East Door to Aux Bldg 1011' 56E - Switchgear South East Door to Switchgear Room Temporary Passive (TP) 1014 ft 1011-04 Switchgear Room Room (East) 227 AE-29/ Equipment Access Door Aux Bldg 1011' 19 - Air Compressor Equipment Access Door to Room 19 Temporary Passive (TP) 1014 ft 1011-11 to Room 19 Room 228 AE-30/ Corridor Rail Road Siding Access Aux Bldg BOT OF DOOR Aux Bldg Corridor 26 Rail Road Siding Access Temporary Passive (TP) 1014 ft 26 1007'-0" RR Bay 229 CW-14A-F Traveling Screen Sluice IS-Intake 974'-0" Intake Structure Incorporated or Exterior 1014 ft Gates Structure Active (lEA) 230 IS East Wall 1014'-6 "dn to 1007'- IS-Intake 1014'-6 "dn to Intake Structure Incorporated or Exterior 1014 ft 6along col row AA, 1007' Structure 1007'-6"along Passive (IEP) 6" dn to 970'-0" col row AA, 1007'-6" dn to 231 IS Floors 1007'-6",993'-6", 974'-6" IS- Intake 1007'-6",993'- Intake Structure Incorporated or Exterior 1014 ft

& 966'-2" Structure 6", 974'-6" & Passive (IEP) 966'-2" 232 IS North Wall 1014'-6 "dn to 1007'- IS- Intake 1014'-6 "dn to Intake Structure Incorporated or Exterior 1014 ft 6along col row 106, Structure 1007'-6"along Passive (IEP) 105A 1007'-6" dn to 975'- col row 106, 0" 105A 1007'-6" Idrn tn)q7';'-0" I Page 18 of 34

Attachment A - Flooding Walkdown Report Flood Protection Features List 11/21/2012 Fort Calhoun Station Item Feature ID/ Description Bldg./Area CLB Feature Room Other Description Feature/Barrier Type CLB Flood El.

Procedure No. Elevation (if any) At Feature 233 IS South Wall 1014'-6 "dn to 1004'- IS-Intake 1014'-6 "dn to Intake Structure Incorporated or Exterior 1014 ft 6"along col row 101, Structure 1004'-6"along Passive (IEP) 1007'-6" dn to 985' south col row 101, wall col row 102 985' dn 1007'-6" dn to to 966'-2" 985' south wall col row 102 985' dn to 966-2" 234 IS West Wall 1014'-6 "dn to 1004'- IS-Intake 1014'-6 "dn to Intake Structure Incorporated or Exterior 1014 ft 6"along col row DD, west Structure 1004'-6"along Passive (IEP) wall 21'-4 7/8" west of col row DD, col row DD 1004'-6" dn to west wall 21-4 974'-8" 7/8" west of col row DD 1004'-6" dn to 974'-8" 235 IS-E-01 120 vac power receptical IS-Intake 1007'-6" IS- Intake Structure 120 vac power receptical penetration Incorporated or Exterior 1014 ft penetration Structure __EP) Passive 236 IS-E-02 120 vac power receptical IS-Intake 1007-6" IS - Intake Structure 120 vac power receptical penetration Incorporated or Exterior 1014 ft Structure

_enetration Passive IEP) 237 IS-E-03 CW-17 Conduit IS-Intake 1004'-6" IS- Intake Structure CW-17 Conduit Penetration from Control Incorporated or Exterior 1014 ft Penetration from Control Structure Station to Motor Passive (IEP)

Station to Motor 238 IS-E-04 CW-17 Conduit IS- Intake 1003'-6" IS-CELL - Intake CW-17 Conduit Penetration Power from Incorporated or Exterior 1014 ft Penetration Power from Structure Structure, intake Cell Cable Tray to Motor Passive (IEP)

Cable Tray to Motor Space 239 IS-E-05 CW-14F Conduit IS- Intake 1004'-6" IS - Intake Structure CW-14F Conduit Penetration from incorporated or Exterior 1014 ft Penetration from Control Structure Control Station to Motor Passive (IEP)

Station to Motor 240 IS-E-06 CW-14F Conduit IS-Intake 1004'-6" IS-CELL - Intake CW-14F Conduit Penetration Power from Incorporated or Exterior 1014 ft Penetration Power from Structure Structure, Intake Cell Cable Tray to Motor Passive (IEP)

Cable Tray to Motor Space 241 IS-E-07 CW-14 Conduit IS-Intake 1004'-6" IS - Intake Structure CW-14 Conduit Penetration from Control Incorporated or Exterior 1014 ft Penetration from Control Structure Station to Motor Passive (IEP)

Station to Motor I I Page 19 of 34

Attachment A - Flooding Walkdown Report Flood Protection Features List 11/21/2012 Fort Calhoun Station Item Feature ID/ Description Bldg./Area CLB Feature Room Other Description Feature/Barrier Type CLB Flood El.

Procedure No. Elevation (if any) At Feature 242 IS-E-08 CW-14E Conduit IS- Intake 1004'-6" IS-CELL - Intake CW-14E Conduit Penetration Power Incorporated or Exterior 1014 ft Penetration Power from Structure Structure, Intake Cell from Cable Tray to Motor Passive (IEP)

Cable Tray to Motor Space 243 IS-E-09 CW-14D Conduit IS-Intake 1004'-6" IS- Intake Structure CW-14D Conduit Penetration from Incorporated or Exterior 1014 ft Penetration from Control Structure Control Station to Motor Passive (IEP)

Station to Motor 244 IS-E-10 CW-14D Conduit IS-Intake 1004'-6" IS-CELL - Intake CW-14D Conduit Penetration Power Incorporated or Exterior 1014 ft Penetration Power from Structure Structure, Intake Cell from Cable Tray to Motor Passive (IEP)

Cable Tray to Motor Space 245 IS-E-11 CW-14C Conduit IS-Intake 1004'-6" IS- Intake Structure CW-14C Conduit Penetration from Incorporated or Exterior 1014 ft Penetration from Control Structure Control Station to Motor Passive (IEP)

Station to Motor 246 IS-E-12 CW-14C Conduit IS-Intake 1004'-6" IS-CELL - Intake CW-14C Conduit Penetration Power Incorporated or Exterior 1014 ft Penetration Power from Structure Structure, Intake Cell from Cable Tray to Motor Passive (IEP)

Cable Tray to Motor Space 247 IS-E-13 CW-14B Conduit IS- Intake 1004'-6" IS- Intake Structure CW-14B Conduit Penetration from Incorporated or Exterior 1014 ft Penetration from Control Structure Control Station to Motor Passive (IEP)

Station to Motor 248 IS-E-14 CW-14B Conduit IS- Intake 1004'-6" IS-CELL - Intake CW-14B Conduit Penetration Power Incorporated or Exterior 1014 ft Penetration Power from Structure Structure, Intake Cell from Cable Tray to Motor Passive (IEP)

Cable Tray to Motor Space 249 IS-E-15 CW-14A Conduit IS-Intake 1004'-6" IS- Intake Structure CW-14A Conduit Penetration from Incorporated or Exterior 1014 ft Penetration from Control Structure Control Station to Motor Passive (IEP)

Station to Motor 250 IS-E-16 CW-14A Conduit IS-Intake 1004'-6" IS-CELL - Intake CW-14A Conduit Penetration Power Incorporated or Exterior 1014 ft Penetration Power from Structure Structure, Intake Cell from Cable Tray to Motor Passive (IEP)

Cable Tray to Motor Space 251 IS-E-17 Compressed Air to IS- Intake 1004' 0" IS- Intake Structure Compressed Air to Veranda Penetration Incorporated or Exterior 1014 ft Veranda Penetration Structure Passive (IEP) 252 IS-E-18 "A" Cell Screen Wash IS- Intake 974-8" IS-CW - Circulating "A" Cell Screen Wash Suction Incorporated or Exterior 1014 ft Suction Penetration Structure Water Pump Bay Penetration Passive (IEP) 253 IS-E-19 "B" Cell Screen Wash IS- Intake 974'-8" IS-CW - Circulating "B" Cell Screen Wash Suction Incorporated or Exterior 1014 ft Suction Penetration Structure Water Pump Bay Penetration Passive (IEP)

Page 20 of 34

Attachment A - Flooding Walkdown Report Flood Protection Features List 11/21/2012 Fort Calhoun Station Item Feature ID/ Description Bldg./Area CLB Feature Room Other Description Feature/Barrier Type CLB Flood El.

Procedure No. Elevation (if any) At Feature 254 IS-E-20 "C" Cell Screen Wash IS- Intake 974'-8" IS-CW - Circulating "C"Cell Screen Wash Suction Incorporated or Exterior 1014 ft Suction Penetration Structure Water Pump Bay Penetration Passive (IEP) 255 IS-E-21 Surface Sluide IS-Intake 9881-6" IS-CELL - Intake Surface Sluice Penetration incorporated or Exterior 1014 ft Penetration Structure Structure, Intake Cell Passive (IEP)

Space 256 IS-E-22 IS-2 Security Card Reader IS-Intake 1007'-6" IS - Intake Structure IS-2 Security Card Reader Penetration Incorporated or Exterior 1014 ft Penetration Structure Passive (IEP) 257 IS-E-23 "F" Cell Grid Backwash IS- Intake 998'-10" IS-CELL - Intake "F" Cell Grid Backwash Penetration Incorporated or Exterior 1014 ft Penetration Structure Structure, Intake Cell Passive (IEP)

Space 258 IS-E-24 "E" Cell Grid Backwash IS-Intake 998'-10" IS-CELL - Intake "E" Cell Grid Backwash Penetration Incorporated or Exterior 1014 ft Penetration Structure Structure, Intake Cell Passive (IEP)

Space 259 IS-E-25 "D"Cell Grid Backwash IS- Intake 998'-10" IS-CELL - Intake "D" Cell Grid Backwash Penetration Incorporated or Exterior 1014 ft Penetration Structure Structure, Intake Cell Passive (IEP)

Space 260 IS-E-26 "C" Cell Grid Backwash IS- Intake 9981-10" IS-CELL - Intake "C" Cell Grid Backwash Penetration Incorporated or Exterior 1014 ft Penetration Structure Structure, Intake Cell Passive (IEP)

Space 261 IS-E-27 "B" Cell Grid Backwash IS- Intake 998'-10" IS-CELL - Intake "B" Cell Grid Backwash Penetration Incorporated or Exterior 1014 ft Penetration Structure Structure, Intake Cell Passive (IEP)

Space 262 IS-E-28 "A" Cell Grid Backwash IS- Intake 998'-10" IS-CELL - Intake "A" Cell Grid Backwash Penetration Incorporated or Exterior 1014 ft Penetration Structure Structure, Intake Cell Passive (IEP)

Space 263 IS-E-30 Surface Sluice Air Hoist IS- Intake 1003'-6" IS-CELL - Intake Surface Sluice Air Hoist Power Conduit Incorporated or Exterior 1014 ft Power Conduit Structure Structure, Intake Cell Penetration Passive (IEP)

Penetration Space 264 IS-E-31 IS-3 Security Card Reader IS- Intake 1007'-6" IS - Intake Structure IS-3 Security Card Reader Penetration Incorporated or Exterior 1014 ft Penetration Structure Passive {IEP) 265 IS-E-34 Trash Rack Sluice Hoist IS- Intake 10081-9" IS- Intake Structure Trash Rack Sluice Hoist Cable Temporary Passive (TP) 1014 ft Cable Structure 266 IS-E-35 Trash Rack Sluice Hoist IS- Intake 1008' 9" IS- Intake Structure Trash Rack Sluice Hoist Control Rod Temporary Passive (TP) 1014 ft Control Rod Structure Page 21 of 34

Attachment A - Flooding Walkdown Report Flood Protection Features List 11/21/2012 Fort Calhoun Station Item Feature ID/ Description Bldg./Area CLB Feature Room Other Description Feature/Barrier Type CLB Flood El.

Procedure No. Elevation (if any) At Feature 267 IS-E-40 Flood barrier for South IS- Intake 1007'-6" IS - Intake Structure Temporary Flood Barrier Temporary Passive (TP) 1014 ft East intake structure door Structure (IS-2) 268 IS-E-41 Flood barrier for North IS- Intake 1007'-6" IS - Intake Structure Temporary Flood Barrier Temporary Passive (TP) 1014 ft East intake structure door Structure (IS-3) 269 IS-E-42 Intake Structure El 974'-8 IS- Intake 974' 8" IS-CW - Circulating Intake Structure El 974'-8 Ground Wire Incorporated or Exterior 1014 ft Ground Wire (South) Structure Water Pump Bay (South) Passive (IEP) 270 IS-E-43 Intake Structure El 974'-8 IS- Intake 974' 8" IS-CW - Circulating Intake Structure El 974'-8 Ground Wire Incorporated or Exterior 1014 ft Ground Wire (North) Structure Water Pump Bay (North) Passive (IEP) 271 IS-F-01 FP-1B Relief Valve Return IS- Intake 993' 6" IS-RW - Raw Water FP-1B Relief Valve Return to Cell Incorporated or Exterior 1014 ft to Cell Penetration Structure Pump Bay Penetration Passive (IEP) 272 IS-F-02 FP-1A Suction Casing IS- Intake 993' 6" IS-RW - Raw Water FP-1A Suction Casing Penetration Incorporated or Exterior 1014 ft Penetration Structure Pump Bay Passive (IEP) 273 IS-F-03 FP-1A Relief Valve Return IS- Intake 993' 6" IS-RW - Raw Water FP-1A Relief Valve Return to Cell Incorporated or Exterior 1014 ft to Cell Penetration Structure Pump Bay Penetration Passive (IEP) 274 IS-F-04 FP-1B Suction IS- Intake 993' 6" IS-RW - Raw Water FP-1B Suction Penetration Incorporated or Exterior 1014 ft Penetration Structure Pump Bay Passive (IEP) 275 IS-F-20 "A" Raw Water Pump IS- Intake 993'-6" IS - Intake Structure "A" Raw Water Pump Penetration Incorporated or Exterior 1014 ft Penetration Structure Passive (IEP) 276 IS-F-21 "B" Raw Water Pump IS- Intake 993'-6" IS- Intake Structure "B" Raw Water Pump Penetration Incorporated or Exterior 1014 ft Penetration Structure Passive (IEP) 277 IS-F-22 "C" Raw Water Pump IS-Intake 993'-6" IS- Intake Structure "C" Raw Water Pump Penetration Incorporated or Exterior 1014 ft Penetration Structure Passive (IEP) 278 IS-F-23 "D" Raw Water Pump IS- Intake 993'-6" IS - Intake Structure "D"Raw Water Pump Penetration Incorporated or Exterior 1014 ft Penetration Structure Passive (IEP) 279 IS-F-25 B-C Cell Cross Connect IS- Intake 993' 6" IS-RW - Raw Water B-C Cell Cross Connect Gate Operator Incorporated or Exterior 1014 ft Gate Operator Structure Pump Bay Penetration Passive (IEP)

Penetration I I Page 22 of 34

Attachment A - Flooding Walkdown Report Flood Protection Features List 11/21/2012 Fort Calhoun Station Item Feature ID/ Description Bldg./Area CLB Feature Room Other Description Feature/Barrier Type CLB Flood El.

Procedure No. Elevation (if any) At Feature 280 IS-F-26 A-B Cell Cross Connect IS- Intake 993' 6" IS-RW - Raw Water A-B Cell Cross Connect Gate Operator Incorporated or Exterior 1014 ft Gate Operator Structure Pump Bay Penetration Passive (IEP)

Penetration 281 IS-F-27 "C" Circulating Pump IS-Intake 993' 6" IS-RW - Raw Water "C" Circulating Pump Suction Gate Incorporated or Exterior 1014 ft Suction Gate Operator Structure Pump Bay Operator Penetration Passive (IEP)

Penetration 282 IS-F-28 "B" Circulating Pump IS- Intake 993' 6" IS-RW - Raw Water "B" Circulating Pump Suction Gate Incorporated or Exterior 1014 ft Suction Gate Operator Structure Pump Bay Operator Penetration Passive (IEP)

Penetration 283 IS-F-29 "A"Circulating Pump IS-Intake 993' 6" IS-RW - Raw Water "A" Circulating Pump Suction Gate Incorporated or Exterior 1014 ft Suction Gate Operator Structure Pump Bay Operator Penetration Passive (IEP)

Penetration 284 IS-F-33 "A" Raw Water Strainer IS- Intake 993'-6" 1S-RW - Raw Water "A"Raw Water Strainer Back Wash Incorporated or Exterior 1014 ft Back Wash Penetration Structure Pump Bay Penetration Passive (IEP) 285 1S-F-34 "B" Raw Water Strainer IS-Intake 993'-6" IS-RW - Raw Water "B" Raw Water Strainer Back Wash Incorporated or Exterior 1014 ft Back Wash Discharge Structure Pump Bay Discharge Penetration Passive (IEP)

Penetration 286 IS-F-35 River Level Bubbler IS- Intake 1007'-3" IS- Intake Structure River Level Bubbler Tubing Penetration Incorporated or Exterior 1014 ft Tubing Penetration Structure Passive (IEP) 287 IS-N-02 Service Water Supply IS- Intake 997'-0" IS-CW - Circulating Service Water Supply Pipe Penetration Incorporated or Exterior 1014 ft Pipe Penetration Structure Water Pump Bay Passive (IEP) 288 IS-N-03 Potable Water Supply IS- Intake 997'-0" IS-CW - Circulating Potable Water Supply Pipe Penetration Incorporated or Exterior 1014 ft Pipe Penetration Structure Water Pump Bay Passive (IEP) 289 IS-N-04 Capped Pipe Penetration IS- Intake 997'-0" 1S-CW - Circulating Capped Pipe Penetration Incorporated or Exterior 1014 ft Structure Water Pump Bay Passive (IEP) 290 IS-N-05 Capped Pipe Penetration IS- Intake 997'-0" IS-CW - Circulating Capped Pipe Penetration Incorporated or Exterior 1014 ft Structure Water Pump Bay Passive (IEP) 291 IS-N-06 Intake Structure Sump IS- Intake 981'-9" IS-CW - Circulating Intake Structure Sump Pump Discharge Incorporated or Exterior 1014 ft Pump Discharge Structure Water Pump Bay Penetration Passive (IEP)

Penetration 292 IS-N-07 Discharge Tunnel IS- Intake 977'-2" IS- Intake Structure Discharge Tunnel Manhole Penetration Incorporated or Exterior 1014 ft Manhole Penetration Structure Passive (IEP)

Page 23 of 34

Attachment A - Flooding Walkdown Report Flood Protection Features List 11/21/2012 Fort Calhoun Station Item Feature ID/ Description Bldg./Area CLB Feature Room Other Description Feature/Barrier Type CLB Flood El.

Procedure No. Elevation (if any) At Feature 293 IS-N-08 Security System Conduit IS- Intake 1008-1" IS - Intake Structure Security System Conduit Penetration Incorporated or Exterior 1014 ft Penetration Structure Passive (IEP) 294 IS-N-09 Security System Conduit IS- Intake 10081-1" [IS - Intake Structure Security System Conduit Penetration Incorporated or Exterior 1014 ft Penetration Structure Passive (IEP) 295 IS-N-IO Security System Conduit IS-Intake 1007'-5" IS - Intake Structure Security System Conduit Penetration Incorporated or Exterior 1014 ft Penetration Structure Passive (IEP) 296 IS-N-11 Security System Conduit IS- Intake 1007'-5" IS - Intake Structure Security System Conduit Penetration Incorporated or Exterior 1014 ft Penetration Structure Passive (IEP) 297 IS-N-12 "B" Raw Water Strainer IS- Intake 990-0" 1S-RW - Raw Water "B" Raw Water Strainer Discharge Incorporated or Exterior 1014 ft Discharge Penetration Structure Pump Bay Penetration Passive (IEP) 298 &S-N-13 Screen Wash Piping IS- Intake 993'-6" 1S-RW - Raw Water Screen Wash Piping Penetration Incorporated or Exterior 1014 ft Penetration Structure Pump Bay Passive (IEP) 299 IS-N-14 Fire Protection Header IS-Intake 992'-6" IS-CELL - Intake Fire Protection Header Penetration Incorporated or Exterior 1014 ft Penetration Structure Structure, Intake Cell Passive (IEP)

Space 300 IS-N-1S Raw Water Header IS-Intake 9911-0" IS-CELL - Intake Raw Water Header Penetration Incorporated or Exterior 1014 ft Penetration Structure Structure, Intake Cell Passive (IEP)

Space 301 IS-S-03 Vacuum Priming Pipe IS-Intake 996' 0" IS-CW - Circulating Vacuum Priming Pipe Penetration Incorporated or Exterior 1014 ft Penetration Structure Water Pump Bay Passive (IEP) 302 IS-S-04 Service Air Pipe IS-Intake 996' 0" IS-CW - Circulating Service Air Pipe Penetration Incorporated or Exterior 1014 ft Penetration Structure Water Pump Bay Passive (IEP) 303 IS-S-OS Instrument Air Pipe IS-Intake 996' 0" IS-CW - Circulating Instrument Air Pipe Penetration Incorporated or Exterior 1014 ft Penetration Structure Water Pump Bay Passive (IEP) 304 IS-S-06 Potable Water Pipe IS-Intake 996' 0" IS-CW - Circulating Potable Water Pipe Penetration Incorporated or Exterior 1014 ft Penetration Structure Water Pump Bay Passive (IEP) 305 IS-S-07 Service Water Pipe IS-Intake 996'-0" IS-CW - Circulating Service Water Pipe Penetration (capped) Incorporated or Exterior 1014 ft Penetration (capped) Structure Water Pump Bay Passive (IEP)

Page 24 of 34

Attachment A - Flooding Walkdown Report Flood Protection Features List 11/2112012 Fort Calhoun Station Item Feature ID/ Description Bldg./Area CLB Feature Room Other Description Feature/Barrier Type CLB Flood El.

Procedure No. Elevation (if any) At Feature 306 IS-S-08 Fire Protection Header IS-Intake 997-6" IS-CW - Circulating Fire Protection Header Penetration Incorporated or Exterior 1014 ft Penetration Structure Water Pump Bay Passive (IEP) 307 IS-S-09 Auxiliary IS-Intake 996'-0" IS-CW - Circulating Auxiliary Steam/Condensate Penetration Incorporated or Exterior 1014 ft Steam/Condensate Structure Water Pump Bay Passive (IEP)

Penetration 308 IS-S-10 Raw Water Header IS-Intake 994' 0" IS-CW - Circulating Raw Water Header Penetration Incorporated or Exterior 1014 ft Penetration Structure Water Pump Bay Passive (IEP) 309 IS-S-11 "A" Raw Water Strainer IS-Intake 995' 4" IS-RW - Raw Water "A" Raw Water Strainer Discharge Incorporated.or Exterior 1014 ft Discharge Penetration Structure Pump Bay Penetration Passive (IEP) 310 IS-S-12 Instrument Air to RW IS-Intake 1005'-0" IS-RW - Raw Water Instrument Air to RW Pump Bay Incorporated or Exterior 1014 ft Pump Bay Structure Pump Bay Passive (IEP) 311 IS-S-13 Lighting Conduit IS-Intake 1005'-2" lS-RW - Raw Water Lighting Conduit Incorporated or Exterior 1014 ft Structure Pump Bay Passive (IEP) 312 IS-W-01 Pipe Penetration IS-Intake 1000'-6" IS-CW - Circulating Pipe Penetration (Capped) Incorporated or Exterior 1014 ft (Capped) Structure Water Pump Bay Passive (IEP) 313 IS-W-02 Vacuum Priming to IS-Intake 1000'-6" IS-CW - Circulating Vacuum Priming to Pressure Tunnel Incorporated or Exterior 1014 ft Pressure Tunnel Structure Water Pump Bay Penetration Passive (IEP)

Penetration 314 IS-W-03 Vacuum Priming to IS-Intake 1000'-6" IS-CW - Circulating Vacuum Priming to Pressure Tunnel Incorporated or Exterior 1014 ft Pressure Tunnel Structure Water Pump Bay Penetration Passive (IEP)

Penetration 315 IS-W-04 120 vac Power Receptical IS-Intake 1007'-6" IS- Intake Structure 120 vac Power Receptical Penetration incorporated or Exterior 1014 ft Penetration Structure Passive (IEP) 316 IS-W-05 Diesel Driven Fire Pump IS-Intake 1012'-6" IS- Intake Structure Diesel Driven Fire Pump Fuel Oil Incorporated or Exterior 1014 ft Fuel Oil Penetration Structure Penetration Passive (IEP) 317 IS-W-06 Diesel Driven Fire Pump IS-Intake 1014'-0" IS- Intake Structure Diesel Driven Fire Pump Exhaust Incorporated or Exterior 1014 ft Exhaust Penetration Structure Penetration Passive (IEP) 318 IS-W-10 A CW PUMP DISCHARGE IS-Intake 992'-0' IS-CW - Circulating A CW PUMP DISCHARGE PIPE Incorporated or Exterior 1014 ft PIPE Structure Water Pump Bay Passive (IEP)

Page 25 of 34

Attachment A - Flooding Walkdown Report Flood Protection Features List 11/21/2012 Fort Calhoun Station Item Feature ID/ Description Bldg./Area CLB Feature Room Other Description Feature/Barrier Type CLB Flood El.

Procedure No. Elevation (if any) At Feature 319 IS-W-11 B CW PUMP DISCHARGE IS- Intake 992'-0' IS-CW - Circulating B CW PUMP DISCHARGE Incorporated or Exterior 1014 ft Structure Water Pump Bay Passive (IEP) 320 IS-W-12 C CW PUMP DISCHARGE IS- Intake 992'-0' IS-CW - Circulating C CW PUMP DISCHARGE Incorporated or Exterior 1014 ft Structure Water Pump Bay Passive (IEP) 321 IS-W-13 20" PIPE PEN TO DISC IS- Intake 10001-5 IS-CW - Circulating 20" PIPE PEN TO DISC TUNNEL Incorporated or Exterior 1014 ft TUNNEL Structure Water Pump Bay Passive (IEP) 322 IS-W-15 Intake Structure El 974'-8 IS- Intake 974'-8" IS-CW- Circulating Intake Structure El 974'-8 Ground Wire Incorporated or Exterior 1014 ft Ground Wire (South) Structure Water Pump Bay (South) Passive (IEP) 323 IS-W-16 Intake Structure El 974'-8 IS- Intake 974'-8" IS-CW - Circulating Intake Structure El 974'-8 Ground Wire Incorporated or Exterior 1014 ft Ground Wire (North) Structure Water Pump Bay (North) Passive (IEP) 324 IS-W-50 Strainer Power Conduit IS- Intake 1005' IS-RW - Raw Water Strainer Power Conduit Penetration Incorporated or Exterior 1014 ft Penetration A7325/PB- Structure Pump Bay A7325/PB-73T Passive (IEP) 73T 325 IS-W-S1 AIPE Original RW Strainer IS- Intake 1004'-10" IS-RW - Raw Water AIPE Original RW Strainer Power Conduit Incorporated or Exterior 1014 ft Power Conduit Structure Pump Bay Penetration Passive (IEP)

Penetration 326 1S-W-52 Ground Wire Penetration IS- Intake 1003'-6" IS-RW - Raw Water Ground Wire Penetration Incorporated or Exterior 1014 ft Structure Pump Bay Passive (IEP) 327 IS-W-53 "A" Strainer Power IS- Intake 996'-6" IS-RW - Raw Water "A" Strainer Power Conduit Penetration Incorporated or Exterior 1014 ft Conduit Penetration Structure Pump Bay Passive (IEP) 328 IS-W-54 PA System Conduit IS- Intake 1005'-0" IS-RW - Raw Water PA System Conduit Penetration Incorporated or Exterior 1014 ft Penetration Structure Pump Bay Passive (IEP) 329 IS-W-55 LT-2889 Control Conduit IS- Intake 1004'-0" IS-RW - Raw Water LT-2889 Control Conduit Penetration Incorporated or Exterior 1014 ft Penetration EB7311 Structure Pump Bay EB7311 Passive (IEP) 330 IS-W-56 RW Valve Control IS- Intake 1002'-6" IS-RW - Raw Water RW Valve Control Conduit Penetration Incorporated or Exterior 1014 ft Conduit Penetration Structure Pump Bay EA7313/EA7306 Passive (IEP)

EA7313/EA7306 331 1S-W-57 AIPE/ AC-10A Motor IS- Intake 1005'-0" IS-RW - Raw Water AIPE/ AC-10A Motor Heater Conduit Incorporated or Exterior 1014 ft Heater Conduit Structure Pump Bay Penetration Passive (IEP)

Penetration I I Page 26 of 34

Attachment A - Flooding Walkdown Report Flood Protection Features List 11/21/2012 Fort Calhoun Station Item Feature ID/ Description Bldg./Area CLB Feature Room Other Description Feature/Barrier Type CLB Flood El.

Procedure No. Elevation (if any) At Feature 332 IS-W-58 AC-10A Motor Power IS-Intake 1002'-6" IS-RW - Raw Water AC-10A Motor Power Conduit EA66 Incorporated or Exterior 1014 ft Conduit EA66 Structure Pump Bay Passive (IEP) 333 IS-W-59 AC-12A Junction Box IS-Intake 1005'-0" IS-RW - Raw Water AC-12AJunction Box Conduit Incorporated or Exterior 1014 ft Conduit Penetration Structure Pump Bay Penetration Passive (IEP) 334 IS-W-60 AC-1OB Motor Power IS- Intake 1002'-6" lS-RW - Raw Water AC-10B Motor Power Conduit Incorporated or Exterior 1014 ft Conduit Penetration EB67 Structure Pump Bay Penetration EB67 Passive (IEP) 335 IS-W-61 RW Valves Control IS- Intake 1002'-6" IS-RW - Raw Water RW Valves Control Conduit Penetration Incorporated or Exterior 1014 ft Conduit Penetration Structure Pump Bay EB7309/EB7214 Passive (IEP)

EB7309/EB7214 336 IS-W-62 RW Valves Control IS- Intake 1002'-6" IS-RW - Raw Water RW Valves Control Conduit Penetration Incorporated or Exterior 1014 ft Conduit Penetration Structure Pump Bay EC7316/EC7320 Passive (IEP)

EC7316/EC7320 337 IS-W-63 AC-10C Motor Heater IS- Intake 1005'-0" IS-RW - Raw Water AC-10C Motor Heater Conduit Incorporated or Exterior 1014 ft Conduit Penetration 7317 Structure Pump Bay Penetration 7317 Passive (IEP) 338 lIS-W-64 AC-10C Motor Power IS- Intake 1002'-6" IS-RW - Raw Water AC-10C Motor Power Conduit Incorporated or Exterior 1014 ft Conduit Penetration EC68 Structure Pump Bay Penetration EC68 Passive (IEP) 339 IS-W-65 AC-10D Motor Power IS- Intake 1002'-6" IS-RW - Raw Water AC-10D Motor Power Conduit Incorporated or Exterior 1014 ft Conduit Penetration Structure Pump Bay Penetration ED69 Passive (IEP)

ED69 340 IS-W-66 AC-10b Motor Heater IS- Intake 1005'-0" IS-RW - Raw Water AC-bOD Motor Heater conduit Incorporated or Exterior 1014 ft conduit Penetration 7324 Structure Pump Bay Penetration 7324 Passive (IEP) 341 IS-W-67 RW Valve Control IS- Intake 1005'-0" IS-RW - Raw Water RW Valve Control Conduit Penetration Incorporated or Exterior 1014 ft Conduit Penetration Structure Pump Bay ED7321/ED7323 Passive (IEP)

E07321/ED7323 342 IS-W-68 Abandon in place IS- Intake 1005'-0" IS-RW - Raw Water Abandon in place Penetration (original Incorporated or Exterior 1014 ft Penetration (original AC- Structure Pump Bay AC-12B Power) Passive (IEP) 12B Power) 343 IS-W-69 AC-12B Power Conduit IS- Intake 1000'-0" IS-RW - Raw Water AC-12B Power Conduit Penetration Incorporated or Exterior 1014 ft Penetration Structure Pump Bay Passive (IEP) 344 IS-W-70 AC-12B Strainer Power IS- Intake 1005'-0" IS-RW - Raw Water AC-12B Strainer Power Conduit Incorporated or Exterior 1014 ft Conduit Penetration Structure Pump Bay Penetration 7334A/B7330 Passive (IEP) 7334A/B7330 I Page 27 of 34

Attachment A - Flooding Walkdown Report Flood Protection Features List 11/21/2012 Fort Calhoun Station Item Feature ID/ Description Bldg./Area CLB Feature Room Other Description Feature/Barrier Type CLB Flood El.

Procedure No. Elevation (if any) At Feature 345 IS-W-71 Lighting Conduit IS- Intake 1003'-6" IS-RW - Raw Water Lighting Conduit Penetration Incorporated or Exterior 1014 ft Penetration Structure Pump Bay Passive (IEP) 346 IS-W-72 Seal Water Backup to RW IS- Intake 1001-0" IS-RW - Raw Water Seal Water Backup to RW Pump Seals Incorporated or Exterior 1014 ft Pump Seals Penetration Structure Pump Bay Penetration Passive (IEP) 347 IS-W-73 Ground Wire Penetration IS- Intake 1003'-6" IS-RW - Raw Water Ground Wire Penetration Incorporated or Exterior 1014 ft Structure Pump Bay Passive (IEP) 348 IS-W-74 Screen Wash Pipe IS- Intake 10001-0" IS-CELL - Intake Screen Wash Pipe Penetration from SW Incorporated or Exterior 1014 ft Penetration from SW Structure Structure, Intake Cell pumps Passive (IEP) pumps Space 349 IS-W-75 Grid Backwash Header IS- Intake 993'-8" IS-CELL - Intake Grid Gackwash Header Penetration Incorporated or Exterior 1014 ft Penetration Structure Structure, Intake Cell Passive (IEP)

Space 350 IS-W-76 Compressed Air Pipe IS- Intake 10011-0" IS-CELL - Intake Compressed Air Pipe Penetration Incorporated or Exterior 1014 ft Penetration Structure Structure, Intake Cell Passive (IEP)

Space 351 LI-1900 River Level Gauge IS- Intake 9991-0" Intake Structure Incorporated or Exterior 1014 ft Structure Active (lEA) 352 MH31-E-03 MH-31 Conduit, 1900 Yard 1002'-7" MH-31 - Man Hole 31 MH-31 Conduit, 1900 series instrument Incorporated or Exterior 1014 ft series instrument conduit conduit Passive (IEP) 353 MH31-E-04 MH-31 Conduit Yard 1002'-7" MH Man Hole 31 MH-31 Conduit Incorporated or Exterior 1014 ft Passive (IEP) 354 MH31-E-0S MH-31 Conduit Yard 996'-7" MH Man Hole 31 Incorporated or Exterior 1014 ft Passive (IEP) 355 MH31-E-06 MH-31 Conduit Yard 997'-7" MH Man Hole 31 Incorporated or Exterior 1014 ft Passive (IEP) 356 MH31-E-07 MH-31 Conduit Yard 998'-7" MH Man Hole 31 Incorporated or Exterior 1014 ft Passive (IEP) 357 MH31-E-08 MH-31 Conduit Yard 1002'-7" MH Man Hole 31 Incorporated or Exterior 1014 ft Passive (IEP)

Page 28 of 34

Attachment A - Flooding Walkdown Report Flood Protection Features List 11/21/2012 Fort Calhoun Station Item Feature ID/ Description Bldg./Area CLB Feature Room Other Description Feature/Barrier Type CLB Flood El.

Procedure No. Elevation (if any) At Feature 358 MH31-E-09 MH-31 Conduit Yard 997'-7" MH Man Hole 31 Incorporated or Exterior 1014 ft Passive (IEP) 359 MH31-E-10 MH-31 Conduit Yard 1001'-7" MH Man Hole 31 Incorporated or Exterior 1014 ft Passive (IEP) 360 MH31-E-11 MH-31 Conduit Yard 998'-7" MH Man Hole 31 Incorporated or Exterior 1014 ft Passive (IEP) 361 MH31-E-12 MH-31 Conduit Yard 998'-7" MH Man Hole 31 Incorporated or Exterior 1014 ft Passive (IEP) 362 MH31-E-13 MH-31 Conduit Yard 995'-7" MH Man Hole 31 Incorporated or Exterior 1014 ft Passive (IEP) 363 MH31-E-14 MH-31 Conduit Yard 995'-7" MH Man Hole 31 Incorporated or Exterior 1014 ft Passive (IEP) 364 MH31-E-15 MH-31 Conduit Yard 1001'-7" MH Man Hole 31 Incorporated or Exterior 1014 ft Passive (IEP) 365 MH31-E-16 MH-31 Conduit Yard 1001'-7" MH Man Hole 31 Incorporated or Exterior 1014 ft Passive (IEP) 366 MH31-E-17 MH-31 Conduit Yard 1002'-7" MH Man Hole 31 Incorporated or Exterior 1014 ft Passive (IEP) 367 MH31-E-18 MH-31 Conduit Yard 995'-7" MH Man Hole 31 Incorporated or Exterior 1014 ft Passive (IEP) 368 MH31-E-19 MH-31 Conduit Yard 997'-7" MH Man Hole 31 Incorporated or Exterior 1014 ft Passive (IEP) 369 MH31-E-20 MH-31 Conduit Yard 996'-7" MH Man Hole 31 Incorporated or Exterior 1014 ft Passive (IEP) 370 MH31-E-21 MH-31 Conduit Yard 1002'-7" MH Man Hole 31 Incorporated or Exterior 1014 ft Passive (IEP)

Page 29 of 34

Attachment A - Flooding Walkdown Report Flood Protection Features List 11/21/2012 Fort Calhoun Station Item Feature ID/ Description Bldg./Area CLB Feature Room Other Description Feature/Barrier Type CLB Flood El.

Procedure No. Elevation (if any) At Feature 371 MH31-E-22 MH-31 Conduit Yard 1002'-7" MH Man Hole 31 Incorporated or Exterior 1014 ft Passive (IEP) 372 MH31-E-25 MH-31 Conduit Yard 998'-7" MH Man Hole 31 Incorporated or Exterior 1014 ft Passive (IEP) 373 MH31-E-26 MH-31 Conduit Yard 998'-7" MH Man Hole 31 Incorporated or Exterior 1014 ft Passive (IEP) 374 MH31-E-27 MH-31 Conduit Yard 1001'-7" MH Man Hole 31 Incorporated or Exterior 1014 ft Passive (IEP) 375 MH31-E-28 MH-31 Conduit Yard 997'-7" MH Man Hole 31 Incorporated or Exterior 1014 ft Passive (IEP) 376 MH31-E-29 MH-31 Conduit Yard 1002'-7" MH Man Hole 31 Incorporated or Exterior 1014 ft Passive (IEP) 377 MH31-E-30 MH-31 Conduit Yard 998'-7" MH Man Hole 31 Incorporated or Exterior 1014 ft Passive (IEP) 378 MH31-E-31 MH-31 Conduit Yard 997'-7" MH Man Hole 31 Incorporated or Exterior 1014 ft Passive (IEP) 379 MH31-E-32 MH-31 Conduit Yard 996'-7" MH Man Hole 31 Incorporated or Exterior 1014 ft Passive (IEP) 380 MH31-E-33 MH-31 Conduit Yard 996'-7" MH Man Hole 31 Incorporated or Exterior 1014 ft Passive (IEP) 381 MH31-E-34 MH-31 Conduit Yard 997'-7" MH Man Hole 31 Incorporated or Exterior 1014 ft Passive (IEP) 382 MH31-E-35 MH-31 Conduit Yard 996'-7" MH Man Hole 31 Incorporated or Exterior 1014 ft Passive (IEP) 383 MH31-E-36 MH-31 Conduit Yard 1002'-7" MH Man Hole 31 Incorporated or Exterior 1014 ft Passive (IEP)

Page 30 of 34

Attachment A - Flooding Walkdown Report Flood Protection Features List 11/21/2012 Fort Calhoun Station Item Feature ID/ Description Bldg./Area CLB Feature Room Other Description Feature/Barrier Type CLB Flood El.

Procedure No. Elevation (if any) At Feature 384 MH32-E-37 MH-31 Conduit Yard 1001'-7" MH Man Hole 31 Incorporated or Exterior 1014 ft Passive (IEP) 385 MH31-E-38 MH-31 Conduit Yard 1001'-7" MH Man Hole 31 Incorporated or Exterior 1014 ft Passive (IEP) 386 MH31-E-39 MH-31 Conduit Yard 9951-7" MH Man Hole 31 Incorporated or Exterior 1014 ft Passive (IEP) 387 MH31-E-40 MH-31 Conduit Yard 995'-7" MH Man Hole 31 Incorporated or Exterior 1014 ft Passive (IEP) 388 MH31-N-01 Conduit Penetration for Yard 1000'-0" MH Man Hole 31 Conduit Penetration for RW strainer Incorporated or Exterior 1014 ft RW strainer power power Passive (IEP) 389 MH31-N-02 Conduit Penetration for Yard 10001-0" MH Man Hole 31 Conduit Penetration for RW strainer Incorporated or Exterior 1014 ft RW strainer power power Passive (IEP) 390 Proc AOP-01 Acts of Nature N/A N/A N/A N/A Procedure N/A 391 Proc EPIP-TSC-2 Catastrophic Flooding N/A N/A N/A N/A Procedure N/A Preparations 392 Proc PE-RR-AE- Flood Barrier and N/A N/A N/A N/A Procedure N/A 1001 Sandbag Staging and Installation 393 Room 02 Walls and Floors Aux Bldg 1004'-8" Room 2 Incorporated or Exterior 1014 ft Wallls/Floors Passive (IEP) 394 Room 04 Walls and Floors Aux Bldg 989'-8" Room 4 Incorporated or Exterior 1014 ft Walls/Floors Passive (IEP) 395 Room 06 Walls and Floors Aux Bldg 989'-8" Room 6 Incorporated or Exterior 1014 ft

_Wallis/Floors Passive (IEP) 396 Room 07 Walls and Floors Aux Bldg 989'-8" Room 7 Incorporated or Exterior 1014 ft Wallis/Floors Passive (IEP) 397 Room 08 Walls and Floors Aux Bldg 1007'-8" Room 8 Incorporated or Exterior 1014 ft Wallls/Floors Passive (IEP)

Page 31 of 34

Attachment A - Flooding Walkdown Report Flood Protection Features List 11/21/2012 Fort Calhoun Station Item Feature ID/ Description Bldg./Area CLB Feature Room Other Description Feature/Barrier Type CLB Flood El.

Procedure No. Elevation (if any) At Feature 398 Room 09 Walls and Floors Aux Bldg 989'-8" Room 9 Incorporated or Exterior 1014 ft Wallis/Floors Passive (IEP) 399 Room 10 Walls and Floors Aux Bldg 989'-8" Room 10 Incorporated or Exterior 1014 ft WaIlls/Floors Passive (IEP) 400 Room 16 Walls and Floors Aux Bldg 989'-8" Room 16 Incorporated or Exterior 1014 ft Wallis/Floors Passive (IEP) 401 Room 17 Walls and Floors Aux Bldg 1007'-8" Room 17 Incorporated or Exterior 1014 ft Wallls/Floors Passive (IEP) 402 Room 19 Walls and Floors Aux Bldg 989'-1007' Room 19 Fir. El. 989'-0", walls El. 1007' down. Incorporated or Exterior 1014 ft Walls/Floor El. 989'-0" along Col Row C between Passive (IEP)

Col. Rows la & 9 & along Col. Row D between C61. Rows la & 2b 403 Room 22 Walls and Floors Aux Bldg 971'-8" Room 22 Incorporated or Exterior 1014 ft Walls/Floor Passive (IEP) 404 Room 23 Walls and Floors Aux Bldg 971'-8" Room 23 Incorporated or Exterior 1014 ft WallIs/Floors Passive (IEP) 405 Room 24 Walls and Floors Aux Bldg 989'-8" Room 24 Incorporated or Exterior 1014 ft Walls/Floor Passive (IEP) 406 Room 24a Walls and Floors Aux Bldg 989'-8" Room 24a Incorporated or Exterior 1014 ft Wallis/Floors Passive (IEP) 407 Room 25 Walls and Floors Aux Bldg 1004'-8" Room 25 Incorporated or Exterior 1014 ft Walls/Floor Passive (IEP) 408 Room 25a Walls and Floors Aux Bldg 1007'-8" Room 25a Incorporated or Exterior 1014 ft Wallis/Floors Passive (IEP) 409 Room 26 Walls and Floors Aux Bldg 1004'-8" Room 26 Incorporated or Exterior 1014 ft Wallis/Floors Passive (IEP) 410 Room 27 Walls and Floors Aux Bldg 1007'-8" Room 27 Incorporated or Exterior 1014 ft Walls/Floor Passive (IEP) 411 Room 29 Walls and Floors Aux Bldg 1004'-8" Room 29 Incorporated or Exterior 1014 ft Walls/Floor Passive (IEP) 412 Room 34 Walls and Floors Aux Bldg 1004'-8" Room 34 Incorporated or Exterior 1014 ft WaIlls/Floors Passive (IEP)

Page 32 of 34

Attachment A - Flooding Walkdown Report Flood Protection Features List 11121/2012 Fort Calhoun Station Item Feature ID/ Description Bldg./Area CLB Feature Room Other Description Feature/Barrier Type CLB Flood El.

Procedure No. Elevation (if any) At Feature 413 Room 52 Walls and Floors Aux Bldg 1004'-8" Room 52 Incorporated or Exterior 1014 ft Wallls/Floors Passive (IEP) 414 Room 56 Fir. Slab 1011' & walls Aux Bldg 1011' - 1014' Room 56 Fir. Slab 1011' & walls along Col. Incorporated or Exterior 1014 ft Walls/Floor along Col. Rows C &D Rows C & D between Col. Rows la Passive (IEP) between Col. Rows la thru Col. Row 9 thru Col. Row 9 415 Room 63 1007"-0" to 1014'-0" Aux Bldg 1007'-0" Room 63 Flr.DG-#1 Flr.1007"-O", walls 1014, Incorporated or Exterior 1014 ft Walls/Floor DG#1 dn. 1007'-0" along Col Row la, & 64' Passive (IEP) west of Col. Row D, 15' north of Col. Row DG-#1 DG-#2 Divider wall (south face) & wall Along Col. Row D.1007', Walls 1014 dn. To 1007, 416 SD-127 Drain line Isolation valve Aux Bldg 999'-0" Room 19 Manual Isolation Valve, TCS Drains to Aux Incorporated or Exterior 1014 ft Bldg Active ( EA) 417 SD-128 Drain line Isolation valve Aux Bldg 997'-0" Room 19 Manual Isolation Valve, Aux Bldg Drains to Incorporated or Exterior 1014 ft Lift Station Active (IEA) 418 VD-681 Drain line Isolation valve Aux Bldg 10111-0" 56 - Switchgear Room SWITCHGEAR ROOM A AHU VA-87 DRAIN Incorporated or Exterior 1014 ft LINE ISOLATION VALVE Active (lEA) 419 VD-682 Drain line Isolation valve Aux Bldg 10111-0" 56- Switchgear Room UP ELEC PENN &SWTCHGR AHU VA-85, 86 & Incorporated or Exterior 1014 ft 88 DRAIN LINE SOL VALVE Active (lEA) 420 WD-1303 Drain line Isolation valve Aux Bldg 989'-0" Room 10 Isolation Valve, CARP TO SPENT REGEN Incorporated or Exterior 1014 ft TANK Active (lEA) 421 WD-250 Drain line Isolation valve Aux Bldg 993'-0" Room 24A ISOLATION VALVE, RAILROAD DOCK AREA Incorporated or Exterior 1014 ft SUMP Active (lEA) 422 WD-1216 Rad 1005'-0" Room 502 Incorporated or Exterior 1014 ft Sump Pump WD-30B WasteBldg. Sump Pump WD-30B Discharge Isolation Active (IEA)

Discharge Isolation Valve Valve _

423 WD-1217 Rad 10101-0" Room 506 Incorporated or Exterior 1014 ft Sump Pump WD-30A WasteBldg. Sump Pump WD-30A Discharge Isolation Active (lEA)

Discharge Isolation Valve _ Valve Page 33 of 34

Attachment A - Flooding Walkdown Report Flood Protection Features List 11/21/2012 Fort Calhoun Station Item Feature ID/ Description Bldg./Area CLB Feature Room Other Description Feature/Barrier Type CLB Flood El.

Procedure No. Elevation (if any) At Feature 424 WD-1218 Rad 1010'-0" Room 506 Incorporated or Exterior 1014 ft Pump WD-31B Discharge WasteBldg. Active (lEA)

Isolation Valve Pump WD-31B Discharge Isolation Valve 425 WD-1219 Rad 10101-0" Room 506 Incorporated or Exterior 1014 ft Pump WD-31A Discharge WasteBldg. Active (lEA)

Isolation Valve I Pump WD-31A Discharge Isolation Valve Page 34 of 34

ML123350124

Text

SUMMARY

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