Text

Company, Llc'S 180-day Response to NRC Request for Information Pursuant to 10 CFR 50.54(f) Regarding the Flooding Aspects of Recommendation 2.3 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident
	ML123250714
Person / Time
Site:	Peach Bottom
Issue date:	11/19/2012
From:	Jesse M; Exelon Generation Co
To:	; Document Control Desk, Office of Nuclear Reactor Regulation
References
	RS-12-174
	Download: ML123250714 (106)
	v • d • e

10 CFR 50.54(f)

RS-12-174 November 19, 2012 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk 11555 Rockville Pike Rockville, MD 20852 Peach Bottom Atomic Power Station, Units 2 and 3 Renewed Facility Operating License Nos. DPR-44 and DPR-56 NRC Docket Nos. 50-277 and 50-278

Subject:

Exelon Generation Company, LLC's 180-day Response to NRC Request for Information Pursuant to 10 CFR 50.54(f) Regarding the Flooding Aspects of Recommendation 2.3 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident

References:

1. NRC Letter, 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 March 12, 2012

2. Exelon Generation Company, LLC's 90-day Response to NRC Request for Information Pursuant to 10 CFR 50.54(f) Regarding Recommendations 2.1 and 2.3, of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident (Flooding), dated June 11,2012

3. NRC Letter, "Endorsement of Nuclear Energy Institute (NEI) 12-07, "Guidelines For Performing Verification Walkdowns of Plant Flood Protection Features," dated May 31, 2012 On March 12,2012, the Nuclear Regulatory Commission (NRC) issued Reference 1 to all power reactor licensees. Enclosure 4 of Reference 1 contains specific Requested Actions, Requested Information, and Required Responses associated with Recommendation 2.3 for Flooding. On June 11, 2012, Exelon Generation Company, LLC (EGC) submitted the 90-day response (Reference 2) requested in Enclosure 4 of Reference 1, confirming that EGC would use the NRC-endorsed flooding walkdown procedure.

U.S. Nuclear Regulatory Commission 180-Day Response to 50.54(f) Letter NTTF Recommendation 2.3: Flooding November 19, 2012 Page 2 For flooding Recommendation 2.3 (walkdowns), Enclosure 4 of Reference 1 states that within 180 days of the NRC's endorsement of the walkdown process (Reference 3), each addressee will submit a final response, including a list of any areas that are unable to be inspected due to inaccessibility and a schedule for when the walkdown will be completed. This letter provides the Peach Bottom Atomic Power Station, Units 2 and 3 (PBAPS Units 2 and 3) 180-day response to Reference 1 for Flooding Recommendation 2.3.

Conditions identified during the walkdowns were documented and entered into the corrective action program. to this letter provides the requested information for PBAPS Units 2 and 3.

This letter contains new regulatory commitments, which are identified in Enclosure 2.

Should you have any questions concerning the content of this letter, please contact Ron Gaston at (630) 657-3359.

I declare under penalty of perjury that the foregoing is true and correct. Executed on the 19th day of November 2012.

Respectfully,

Enclosures:

1. Flooding Walkdown Report In Response To The 50.54(f) Information Request Regarding Near-Term Task Force Recommendation 2.3: Flooding for the Peach Bottom Atomic Power Station, Units 2 and 3

2. Summary of Regulatory Commitments

U.S. Nuclear Regulatory Commission 180-Day Response to 50.54(f) Letter NTTF Recommendation 2.3: Flooding November 19, 2012 Page 3 cc: Director, Office of Nuclear Reactor Regulation Regional Administrator - NRC Region I NRC Senior Resident Inspector - PBAPS Units 2 and 3 NRC Project Manager, NRR - PBAPS Units 2 and 3 Director, Bureau of Radiation Protection - Pennsylvania Department of Environmental Resources S. T. Gray, State of Maryland R. R. Janati, Chief, Division of Nuclear Safety, Pennsylvania Department of Environmental Protection, Bureau of Radiation Protection

U.S. Nuclear Regulatory Commission 180-Day Response to 50.54(f) Letter NTTF Recommendation 2.3: Flooding November 19, 2012 Page 5 Enclosure 1 Flooding Walkdown Report In Response To The 50.54(f) Information Request Regarding Near-Term Task Force Recommendation 2.3: Flooding for the Peach Bottom Atomic Power Station, Units 2 and 3 (100 pages)

I PEACH BOTTOM ATOMIC POWER STATION 1848 Lay Road, Delta, PA 17314 Facility Operating License Nos. DPR-44 & DPR-56 NRC Docket Nos. 50-277 & 50-278 Exelon Generation Company, LlC 300 Exelon Way Kennett Square, PA 19348 Prepared by:

ENERCON 12420 Milestone Center Drive, Suite 200 Germantown, MD 20876 November 5, 2012 Printed Name Signature Date EOC Preparer: Tom O'Reilly 11/5/12 EOC Reviewer: Waseem Chughtai 11/5/12 EOC Approver: Ray Sacramo 11/5/12 Lead Responsible Engineer: J'e ~.se LvLI\S "1511'2-Branch Manager: -rC~6"

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Senior Manager Design Engineering: (f1'~ L"-'flDtytV Corporate Acceptance: Joseph V. Bellini 11/07/12

NTIF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 Contents

1. EXECUTIVE

SUMMARY

............................................................................................................................... 2

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

a. Background ............................................................................................................................................ 3

b. Site Description ...................................................................................................................................... 4

c. Requested Actions ................................................................................................................................. 4

d. Requested Information .......................................................................................................................... 5

3. METHODOLOGY ......................................................................................................................................... 6

a. Overview of NE112-07 (Walkdown Guidance) ...................................................................................... 6

b. Application of NE112-07 ........................................................................................................................ 7

c. Reasonable Simulations ......................................................................................................................... 8

d. Walkdown Inspection Guidance .......................................................................................................... 12

4. RESULTS ................................................................................................................................................... 13

a. Requested Information Item 2(a) - Design Basis Flood Hazards ......................................................... 13

b. Requested Information Item 2(b) - CLB Protection and Mitigation Features ..................................... 15

c. Requested Information Item 2(c) - Flood Warning Systems ............................................................... 16

d. Requested Information Item 2(d) - Flood Protection System/Barrier Effectiveness .......................... 17

e. Requested Information Item 2(e) -Implementation of Walkdown Process ....................................... 20

f. Requested Information Item 2(f) - Findings and Corrective Actions Taken/Planned ......................... 20

g. Requested Information Item 2(g) - Cliff -Edge Effects and Available Physical Margin ....................... 21

h. Requested Information Item 2(h) - Planned/Newly-Installed Flood Protection Enhancements ........ 22

5. CONCLUSIONS .......................................................................................................................................... 22

6. REFERENCES ............................................................................................................................................. 98 Page 1

NTTF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 This Flooding Walkdown Report provides the Peach Bottom Atomic Power Station (PBAPS) response to the Recommendation 2.3 Flooding Enclosure 4 of the March 12, 2012 10CFR50.54(f) letter concerning the Near Term Task Force (NTIF) review of the accident at the Fukushima-DaHchi nuclear facility. To address Recommendation 2.3, walkdowns were performed to verify that plant features credited in the current licensing basis (CLB) for protection and mitigation from external flood events are available, functional, and properly maintained. Additionally, simulations of actions taken to provide flood protection measures credited in the CLB were performed to confirm that the actions could be executed as defined in plant procedures. Based on walkdowns, simulations and review, it is concluded that the flood protection features at PBAPS are capable of performing their licensed design function. In addition, flood mitigation procedures can be implemented in time to safely mitigate the design basis flood.

The effort was accomplished by following the guidance in NEI 12-07, Rev. O-A, "Guidelines for Performing Verification Walkdowns of Plant Flood Protection Features". The CLB flood levels were identified and then plant features credited in the CLB to protect against the flood level and/or mitigate the flood were identified. The features include passive items such as walls and penetration seals, and active items such as watertight doors. Flood protection actions taken via plant procedures were identified. Walkdown packages were assembled for each feature to identify its location, critical characteristics, and acceptance criteria in order to be properly prepared for the visual inspection performed on the walkdown. Similarly, a plan was developed for the reasonable simulations to accurately mimic the flood protection actions accomplished in the procedures.

The scope of the PBAPS walkdowns included a visual inspection of the features currently credited for protection from external floods. These features create the external flood barrier for the CLB flood. The features protect the Reactor Building, Emergency Pump Structure, Diesel Generator Building, Emergency Cooling Tower, and Radwaste Building from the CLB flood. 1,409 flood protection features were included in the walkdown scope. Six (6) reasonable simulations were performed to mimic actions that protect the Emergency Pump Structure, the Diesel Generator Building, and the Radwaste Building. A simulation to ensure that the watertight doors are closed and secure demonstrates that the external flood boundary will be maintained. Other simulations included placing the Emergency Cooling Tower in service, which demonstrates transfer of the heat sink from Conowingo Pond to the on-site emergency reservoir as credited in the CLB. The reasonable simulations demonstrated that the actions could be accomplished prior to being impeded by the flood waters. Refer to Table 2 in Section 5 of this report for a list of the reasonable simulations. Manholes in the yard are not external flood protection features.

Results of the flood protection feature walkdowns are categorized as:

a) Immediately Judged as Acceptable, b) Not Immediately Judged as Acceptable (enter into CAP),

c) Restricted Access (inspect at a later time), or d) Inaccessible (cannot be inspected).

All items in the second group - Not Immediately Judged as Acceptable - were determined to be Operable for their external flood protection function.

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NTTF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 All items in the third group - Restricted Access - will be inspected pending Operations risk review, which may require that safety related equipment is de-energized for internal conduit flood seal inspections.

All items in the fourth group Inaccessible have reasonable assurance that the components will perform their external flood protection function.

Section 5 of this report has a separate table for each group, with component 10 numbers.

2. PURPOSE

a. Background In response to the nuclear fuel damage at the Fukushima-OaHchi 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 reported 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 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'.)

Structures, systems, and components (SSCs) important to safety are designed either in accordance with, or meet the intent of, Appendix A to 10 CFR Part 50, General Design Criteria (GDC) 2. GDC 2 states that SSCs important to safety at nuclear power plants must be designed to withstand the effects of natural phenomena, including floods, without loss of capability to perform their intended safety functions. For flooding walkdowns, identifying/addressing plant-specific degraded, nonconforming, or unanalyzed conditions (through the corrective action program) and verifying the adequacy of monitoring and maintenance procedures is associated with flood protection and mitigation features credited in the current design/licensing basis. New flood hazard information will be considered in response to Enclosure 2 of Reference 3.

On behalf of Exelon Generation Company, LLC (helon), 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'). The 'Requested Information' section of Enclosure 4, paragraph Page 3

NTTF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 1 ('a' through T), regarding flooding walkdown procedures, was addressed via Exelon's June 11, 2012, 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 Susquehanna River and its tributaries form the major drainage system of southeastern Pennsylvania.

The Peach Bottom Atomic Power Station (PBAPS) is located on the west bank of Conowingo Pond, formed in the Susquehanna River by the Conowingo Dam, located 9 miles downstream; and Holtwood Dam, located 6 miles upstream.

The general grade at the PBAPS site is established at Elevation 115 feet in the area surrounding the Turbine Building and other structures on the river side of the plant. Top of ground floor of the structures in this area is at Elevation 116 feet. Grade rises abruptly in the area surrounding the Reactor Building to a nominal elevation of 134 feet with the top of ground floor at elevation 135 feet. All elevations in this report are referenced to the Conowingo Datum (CD.), which is 0.7 feet above mean sea level.

Normal elevation of Conowingo Pond is between 104 feet and 109.25 feet. During the record flood of 1972 the water level rose to 113.5 feet, exclusive of wave run-up.

The Probable Maximum Flood (PMF) of 1,750,000 cfs produces a still-water level at PBAPS of 131.5 feet.

Combined with a postulated Holtwood Dam failure, evaluated to produce a transient wave of 0.5 feet, results in a maximum still-water elevation of 132.0 feet. Peach Bottom structures required for safe shutdown are flood protected to elevation 135 feet, which is 3.5 feet of margin above the maximum calculated still-water level.

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 11, 2012 (Reference 1), Exelon 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.

Other NRC's requested actions include:

(1) Perform flood protection walkdowns using an NRC-endorsed walkdown methodology; Page 4

NTIF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 (2) Identify and address plant~specific degraded, nonconforming, or unanalyzed conditions, as well as, cliff-edge effects through the corrective action program, and consider these findings in the Recommendation 2.1 hazard evaluations, as appropriate; (3) Identify any other actions taken or planned to further enhance the site flood protection; (4) Verify the adequacy of programs, monitoring and maintenance for protection features; and (5) Report to the NRC the results of the walkdowns and corrective actions taken or planned. of Reference 3 also states, 'If any condition identified during the walkdown activities represents a degraded, nonconforming, or unanalyzed condition (i.e. noncompliance with the current licensing basis) for an SSC, describe actions that were taken or are planned to address the condition using the guidance in Reference 6, including entering the condition in the corrective action program. Reporting requirements pursuant to 10 CFR 50.72 should also be considered.

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, helon's letter dated June 11, 2012 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 walkdowns and submit a final report which includes the following:

a. Describe the design basis flood hazard level(s) for all flood-causing mechanisms, including groundwater ingress.

b. Describe protection and mitigation features that are considered in the licensing basis evaluation to protect against external ingress of water into SSCs important to safety.

c. Describe any warning systems to detect the presence of water in rooms important to safety.

d. Discuss the effectiveness of flood protection systems and exterior, incorporated, and temporary flood barriers. Discuss how these systems and barriers were evaluated using the acceptance criteria developed as part of Requested Information item 1.h.

e. 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, including actions taken in response to the peer review.

f. Results of the walkdown including key findings and identified degraded, nonconforming, 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, Revision 1, Revision to NRC Inspection Manual Part 9900 Technical Guidance, "Operability Conditions Adverse to Quality or Safety," including entering the condition in the corrective action program.

g. 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 Page 5

NTTF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 taken or planned to address these effects. See note in Section 2a regarding the NRC's change in position on cliff-edge effects.

h. 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.

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], Guidelines for Performing Verification Walkdowns 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 11, 2012, Exelon issued a letter to the NRC stating that the endorsed flooding walkdown procedure (Reference 2) will be used as the basis for the flooding walkdowns. NE112-07 provides guidance on the following items:

Definitions o Incorporated Barrier/Feature o Temporary Barrier/Feature o Exterior Barrier/Feature o Current Licensing Basis (CLB) o Design Bases o Inaccessible o Restricted Access o Deficiency o Flood Protection Features o Reasonable Simulation o Visual Inspection o Cliff-Edge Effects o Available Physical Margin o Variety Of Site Conditions o Flood Duration

Scope o Basis for Establishing Walkdown Scope o Identify Flood Protection Features (Walkdown List)

Methodology o Develop Walkdown Scope o Prepare Walkdown Packages o Walkdown Team Selection and Training o Perform Pre-Job Briefs o Inspection of Flood Protection And Mitigation Features

General

Incorporated or Exterior Passive Flood Protection Features

Incorporated or Exterior Active Flood Protection Features

Temporary Passive Flood Protection Features Page 6

NTIF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012

Temporary Active Flood Protection Features

Procedure Walk-through and Reasonable Simulation o Review of The Maintenance and Monitoring of Flood Protection Features o Review of Operating Procedures o Documentation of Available Physical Margins o Documenting Possible Deficiencies o Restricted Access, or Inaccessible

Acceptance Criteria

Evaluation and Reporting Results of The Walkdown

Related Information Sources

Examples

Walkdown Record Form

Sample Training Content

Walkdown Report

b. Application of NE112-07 At PBAPS, the approach to the flooding walkdowns included three phases:

Phase 1 - Preparation, Training, Data Gathering, and Scoping The walkdown list was developed using the guidance provided in Section 4.2 of NEI 12-07. The existing design and licensing documents, such as the UFSAR, plant drawings, and flood response procedures, were reviewed to identify the plant features credited for protection and mitigation against external flooding events. Plant specific documents used to develop the walkdown list are identified in the Reference Section.

The critical attributes of each feature are reported in Part A of the NEI 12-07 Walkdown Record Form.

Topics and items reviewed to develop the walkdown list included the following:

The barriers important to resisting the effects of external flooding (e.g., structures, walls, floors, doors, etc.).

Penetrations through barriers, such as trenches and cable openings, that could provide a path for flood water to enter buildings and the means to seal these penetrations. Temporary penetrations and equipment hatches that could provide a path for floodwater to enter buildings were also identified. The means and process to isolate these penetrations, if they are open, within the required time were identified.

Instrumentation relied upon to detect water in rooms and the associated warning system

Features or pathways credited for flood water relief (e.g., surface drainage swales, subsurface drainage system, culverts, floor/yard drains, etc.).

Plant response procedures for external floods to identify any incorporated or exterior equipment that is credited for flood protection or mitigation.

Situations for which temporary plant equipment (e.g., portable pumps, sandbags, temporary barriers, etc.) is credited to protect or mitigate the effects of the external flooding event.

Flood response procedures to evaluate the practicality of the associated actions performed by site personnel, i.e., Reasonable Simulation.

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NTIF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012

Training provided to support implementation of plant flood procedures to determine if it is adequate (content, frequency, and participants) and reflects any time sensitive actions.

PBAPS does not have any flood protection features associated with bullets 3 or 4 as shown in the above list.

A walkdown package was developed for each feature. The purpose of the packages was to ensure that the teams had at their disposal the relevant information to ensure efficient and thorough walkdowns.

In preparation for the actual walkdowns, preliminary walkthroughs of the different areas were conducted.

This activity helped familiarize the team with the conditions as well as offering an opportunity to identify additional features that may not have been identified by review of plant documentation.

Each team member was trained to NEI 12-07 and passed the NANTEL Generic Verification Walkdowns of Plant Flood Protection Features test. Confined space and fall protection training was obtained to prepare for the need to enter confined spaces, such as manholes and access features via ladders and scaffolding.

Phase 2 -Inspections and Reasonable Simulations Visual inspection of each feature was performed on the walkdowns and the results were documented on the Walkdown Record Forms. The condition of each feature as observed on the walkdowns was compared to the acceptance criteria defined in the Supplemental Walkdown/lnspection Guidance (Reference 29).

Six (6) reasonable simulations were performed to demonstrate compliance with licensing basis requirements in regard to protection from external floods. The simulations were walk-throughs of various steps in Flood Procedure SE-4 (Reference 14) that align with licensing basis flood protection commitments and/or protect SSCs required for safe shutdown.

Phase 3 - Final Reporting The Walkdown Record Forms were completed and assembled into a package that included a summary and a cover page to document a management review of the entire package. 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 IIRecommendation 2.3: Flooding" enclosure from the 10CFRS0.54 (f) letter.

c. Reasonable Simulations A procedure walk-through, or 'Reasonable Simulation', was conducted for temporary and/or active features that require manual/operator actions to perform their intended flood protection function. The purpose of the reasonable simulations was to verify that the procedure or activity could be executed as specified/written. Per NEI 12-07 (Reference 2), reasonable simulation included the following:

Verify that any credited time dependent activities can be completed in the time required. Time-dependent activities include detection (some signal that the event will occur, has occurred, or is occurring), recognition (by someone who will notify the plant), communication (to the control room), and action (by plant staff).

Verify that specified equipment/tools are properly staged and in good working condition.

Verify that connection/installation points are accessible.

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NTIF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012

Verify that the execution of the activity will not be impeded by the event it is intended to mitigate or prevent. For example, movement of equipment across unpaved areas on the site could be impeded by soft soil conditions created by excessive water.

Review the reliance on the station staff to execute required flood protection features. If during the review several activities are identified to rely on station staff! then perform and document an evaluation of the aggregate effect on the station staff to demonstrate all actions can be completed as required.

Verify that all resources needed to complete the actions will be available. (Note that staffing assumptions must be consistent with site access assumptions in emergency planning procedures.)

Show that the execution of the activity will not be impeded by other adverse conditions that could reasonably be expected to simultaneously occur (for example, winds, lightning! and extreme air temperatures).

Personnel/departments that have responsibility for supporting or implementing the procedure should participate in the simulation effort.

The simulation should demonstrate that the personnel assigned to the procedure do not have other duties that could keep them from completing their flood protection activities during an actual event. Actions that would be performed in parallel during an event should be simulated in parallel; not checked individually and the results combined.

Reasonable simulation need not require the actual performance of the necessary activities if they have been previously performed and documented or it is periodically demonstrated and documented that the activities can be completed in the credited time.

Six (6) reasonable simulations, listed below! were performed to demonstrate compliance with licensing basis requirements in regard to protection from external floods. The simulations are walk-throughs of specific steps in Flood Procedure SE-4 that align with licensing basis flood protection commitments and/or protect SSCs required for safe shutdown.

Each simulation was timed and the total time to complete was used to determine if the activity could be performed satisfactorily. Per UFSAR Section 2.4.3.5.5 (Reference 13), it is estimated that 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months will elapse as the water rises from elevation 111' to 113', allowing the greatest portion of decay heat to be rejected to the river. Based on this statement, a flood level increase rate of lft/hr is determined. The total time to complete was compared to this rate of rise to determine if the flood level would prevent the activity from being performed.

Simulation #1 protects the emergency pump structure, which houses the ESW and HPSW pumps, by re-aligning the drainage from the protected roof area (inside the parapet) from its normal destination discharging outside the structure to the emergency pump structure sump. This change to the drainage path will prevent flood waters from back flowing to the roof.

Simulation #2 ensures that the external flood boundary is maintained by confirming that water tight doors are closed and secure.

Simulation #3 seals a drain in the Turbine Building that flows to a tank in the Radwaste Building.

This action will prevent overflowing the tank with flood water from the Turbine Building and serves to protect the Radwaste Building from flood water.

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NTTF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012

Simulation #4 opens Turbine Building sump pump breakers, which disables the pumps, to prevent overwhelming the Radwaste system with flood water from the Turbine Building. This action serves to protect the Radwaste BUilding from flood water.

Simulation #5 protects the Diesel Generator Building by preventing backflow through the Diesel Generator Building sump overflow drain line.

Simulation #6 demonstrates placing the Emergency Cooling Water system in service.

Each simulation is described below. The Procedure Instructions are as stated in SEA and SO 48.1.B for all simulations.

Simulation #1 - Valve Positioning in Emergency Pump Structure Applicable Procedure: SE-4, Section 4.3 Procedure Instructions: J£ river elevation at Peach Bottom reaches +111.0 ft, THEN perform the following in the Unit 3 High Pressure Service Water Pump room:

Close HV-0-28A-11443, "Circ Water Pp Structure Roof Drn to Pp Bay Blk Vlv"

Open HV-0-28A-11444, "Circ Water Pp Structure Roof Drn to Sump Blk Valve" Reasonable Simulation:

Dispatch operator from the administration building to position valves.

Record time to reach location of valves and simulate positioning both valves.

Simulation is complete when the operator provides notification that both valves have been positioned.

Simulation #2- Watertight Doors Applicable Procedure: SE-4, Section 4.7.3 Procedure Instructions: J£ the predicted river elevation is in excess of +115.0 ft, THEN immediately Close AND secure sill water tight doors at OR below elevation 116.0 ft ..

The water tight doors at or below elevation 116' are taken from CC-PB-201 and are listed below.

Door #D032 - RADWASTE GENERAL ACCESS AREA / TURBINE BUILDING HALLWAY - el. 91'-6"

Door #D073 - U/2 RBCCW ROOM / TB 2 COND DEMIN HALLWAY - el. 116'

Door #D075 - U/2 BAND D CORE SPRAY ROOM / BAND D CORE SPRAY AIRLOCK - el. 116'

Door #D079 - U/2 TB COND DEMIN HALLWAY / RB SOUTHEAST STAIRWELL - el. 116'

Door #D144 - U/3 TB COND DEMIN HALLWAY / RB NORTHEAST STAIRWELL - el. 116'

Door #D147 U/3 A AND C CORE SPRAY ROOM / BAND D CORE SPRAY AIRLOCK - el. 116'

Door #D149 - U/3 RBCCW ROOM / TB 3 COND DEMIN HALLWAY - el. 116'

Door #C01- U/2 HPSW AND ESW PUMP ROOM - el. 112'

Door #C02 - U/3 HPSW AND ESW PUMP ROOM - el. 112'

Door #C03 - U/2 HPSW AND ESW PUMP ROOM - el. 112'

Door #503 - RADWASTE CORRIDOR TO TURBINE BLDG - el. 116' Page 10

NTIF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 Reasonable Simulation:

Dispatch operator from the administration building to check and simulate securing doors.

Record time to reach location of doors and simulate check and securing of doors.

Simulation is complete when the operator provides notification that all doors have been checked.

Simulation #3 - Turbine Building Floor Drains Applicable Procedure: SE-4, Section 4.7.6 Procedure Instructions: !.E. the predicted river elevation is in excess of +115.0 ft, THEN IF required, take the necessary actions to seal the following Turbine Building drain as directed by Shift Management.

Radioactive Lab Waste floor drain located in old Hot Chemistry Lab.

Reasonable Simulation:

Dispatch operator from the administration building to seal the drain.

Record time to seal the drain.

Simulation is complete when the operator provides notification that the drain has been sealed.

Simulation #4 - Turbine Building Sump Pump Breakers Applicable Procedure: SE-4, Section 4.7.7 Procedure Instructions: !.E. the predicted river elevation is in excess of +115.0 ft, THEN IF required, remove power from the following sump pumps by opening the feeder breaker AND applying an Equipment Status Tag to the control switch AND breaker stating "De-energized in accordance with SE-4" as directed by Shift Management.

2AP045, "Turbine Building Equipment Drain Sump Pump A", 1G4-G-B (3043)

2BP045, "Turbine Building Equipment Drain Sump Pump B", 2G4-G-B (3121)

2AP094, "Turbine Building Equipment Drain Sump Pump A", 1G4-G-B (3041)

2BP094, "Turbine Building Equipment Drain Sump Pump B", 2G4-G-B (3161)

2AP095, "Turbine Building Floor Drain Sump Pump A", 1G4-G-B (3042)

2BP095, "Turbine Building Floor Drain Sump Pump B", 2G4-G-B (3162)

OAP044, "Turbine Building Floor Drain Sump Pump A", 2PS4-W-B (4345)

OBP044, "Turbine Building Floor Drain Sump Pump B", 4PS4-W-B (4454)

3AP045, "Turbine Building Equipment Drain Sump Pump A", 3G4-G-B (3043)

3BP045, "Turbine Building Equipment Drain Sump Pump B", 4G4-G-B (3121)

3AP094, "Turbine Building Equipment Drain Sump Pump A", 3G4-G-B (3041)

3BP094, "Turbine Building Equipment Drain Sump Pump B", 4G4-G-B (3161)

3AP095, "Turbine Building Floor Drain Sump Pump A", 3G4-G-B (3042)

3BP095, "Turbine Building Floor Drain Sump Pump B", 4G4-G-B (3162)

Page 11

NTTF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 Reasonable Simulation:

Dispatch operator from the administration building to simulate opening the breakers.

Record time to open all breakers.

Simulation is complete when the operator provides notification that all breakers have been opened.

Simulation #5 - Diesel Generator Building Oily Waste Valve and 41/ Plug Applicable Procedure: SE-4, Sections 4.7.16 and 4.7.17 Procedure Instructions: lE. the predicted river elevation is in excess of +115.0 ft, THEN, Close HV-0 10152, "DIG Building Oily Waste Interceptor Tank Inlet Block Valve", and Lift the grate above the catch basin located under the fuel oil fill station on the south wall of the Emergency Diesel Generator Building AND install a 4" plug into the drain hole.

Reasonable Simulation:

Dispatch operator from the administration building.

Record time to arrive at location and simulate closing the valve and installing the 4" plug.

Simulation is complete when the operator provides notification that the valve has been closed and the plug is installed.

Simulation #6 - Activation of Emergency Cooling Water System Applicable Procedure: SE-4 Section 4.5, SO 48.1.B Procedure Instructions: lE. river level reaches 113.0 ft, THEN place the Emergency Cooling Water System in service using SO 48.1.B, "Emergency Cooling Water System Startup" (Reference 33).

Reasonable Simulation:

Perform actions that would occur in the Control Room by using the Simulator.

Dispatch operators to perform equipment manipulations in the field as required by SO 48.1.B.

Record total time to perform all steps defined in SO 48.1.B required to place the emergency cooling water system in service.

Simulation is complete when the Emergency Cooling Tower is in service.

d. Walkdown Inspection Guidance A 'Walkdown Inspection Guidance' was developed by Exelon to supplement NEI 12-07 (Reference 2), based largely on Appendix A of NEI 12-07 (Examples). The guidance was intended to supplement, not supersede, NE112-07 and provide inspection guidance for specific features, listed below.

Incorporated or 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. Penetration Seals, Cork Seals) o Passive Flood Barriers or Water Diversion Structures Page 12

NTTF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 o Drains and Catch Basins o Plugs and Manhole Covers o Drainage Pathways (Swales, Subsurface Drainage System, etc.)

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

Incorporated or Exterior Active Features:

o Credited Water Tight Doors o Credited Non-Watertight Doors o Pumps o Water Level Indication o Gate Valves

Temporary Passive Features:

o Portable Flood Barriers and Inflatable Rubber Seals o Flood Gate

Temporary Active Feature o Pumps

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.

The PBAPS site flooding analysis is based on historical data of the six greatest floods at Harrisburg. There are no historical floods on the Susquehanna River resulting from ice jams or landslides. Surges, seiches and tsunamis are not considered in the PBAPS site flooding analysis due to the extremely low probability of occurrence.

The assumptions used in the flooding analysis are as follows:

Rainfall is assumed to fall Simultaneously over the entire Susquehanna River watershed to generate PMF riverflows.

Holtwood Dam is assumed to fail coincident with the PMF.

The Conowingo Dam is assumed to remain intact even as water levels rise above the maximum dam design limits. This maximizes the water level at PBAPS and provides analytical conservatism.

With all gates open, the Conowingo dam spillway and power plant will pass a river flow of 840,000 cfs and maintain normal headwater elevation of 108.5 feet (at Conowingo).

Backwater effect produces a river elevation of 113.0 feet at the PBAPS.

Page 13

NTTF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 Flooding analysis assumptions assure that adequate considerations are formulated to determine the worst case scenario involving flood.

Data on historical floods of the Susquehanna River at Harrisburg, Pennsylvania are compiled in several reports by the Commonwealth of Pennsylvania and the U.S. Geological Survey. In the flood studies performed for PBAPS, the PMF hydrography at the Conowingo Dam is evaluated to be the same as that at Harrisburg with a peak discharge of 1,750,000 CFS.

The PMF was determined by the u.s. Army Corp of Engineers, Baltimore District, utilizing the probable maximum precipitation (PMP) estimated by the u.S. Weather Bureau over the Susquehanna River watershed above Harrisburg, PA. The Corps of Engineers developed tributary hydrographs, using sub-basin rainfall and appropriate unit-hydrographs. Inflows from sub-basins were combined and routed downstream.

Based on historic data from the major floods and backwater computations, the PMF at PBAPS is estimated to be Elevation 131.5 feet.

Coincident with the PMF, Holtwood Dam is evaluated to fail in a manner that results in an instantaneous additional outflow of 200,000 CFS, and at the precise time that produces a maximum water elevation at the PBAPS. The transient wave produced by this failure is estimated to be 0.5 feet at PBAPS. Superimposing the height of the transient wave, conservatively estimated at 0.5 feet, on the steady-state backwater profile at a PMF of 1,750,000 CFS, produces a maximum PBAPS water level of Elevation 132.0 feet.

The height of wind-generated waves is computed using the greatest weighted average fetch, 2.0 miles, which will produce the most severe effect at the PBAPS site.

Postulated waves on Conowingo Pond were determined based on the following conservative conditions and factors:

a sustained wind of 45 MPH for over a 20 minute duration the wind acts on a 2 mile fetch of the Conowingo Pond Significant wave height 2.7 feet, measured from trough to tip, tip assumed to be two-thirds of wave height or 1.8 feet Maximum wave estimated to be approximately 1.67 times greater than significant wave or 4.5 feet, only 1% of all waves reach this maximum height.

Superimposing an additional 1.8 feet of wind-generated waves on the conditions assumed previously yields a peak elevation top of wave tip of Elevation 133.8 feet. Compared to the protection level provided of Elevation 135.0 feet, this leaves additional freeboard of 1.2 feet.

This margin of freeboard, together with the conservative assumptions used in computing the water level under hypothesized PMF conditions, is considered more than adequate for the safety criteria of the plant.

The maximum wave of the spectrum analyzed is estimated to be approximately 1.67 times the significant wave height, or 4.5 feet high. Only a small percentage (1%) of all waves reach this maximum height. Wave run-up is defined as the height above still-water level to which a wave rises when it encounters an obstruction. The wave run-up heights estimated are greater than the height that might occur. It is estimated that the significant waves will run up 3.5 feet and the maximum waves 5.4 feet. The maximum wave run-up superimposed on the steady-state PMF Elevation of 131.5 feet results in an Elevation of 136.9 feet.

Page 14

NTTF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 Groundwater ingress or local intense precipitation is not specifically identified or discussed in the licensing basis.

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 against external ingress of water into SSCs important to safety.

The flooding licensing basis identifies actions taken in response to the rising flood waters, and also describes the protection provided to SSCs important to safety and required for safe shutdown. These actions and protections credited in the CLB are described below.

The flood protection features protect against external floods during all modes of operation. For operating modes where a flood barrier may be removed, the flood procedure, SEA, includes instructions to replace the barrier if the predicted river elevation is in excess of 115'. SE-4 contains steps to review the CC-PB-201 Barrier Breach Log (Reference 27), and AD 20A.1, "Temporary Removal And Installation of Flood Barriers In The Reactor Building Drainage System" (Reference 22) to identify open flood barriers and take the necessary actions to seal them. During an outage, an open barrier could have temporary hoses, cables, or other temporary services running through the opening, which would need to be removed and would add to the time required to seal the barrier. Due to the large number of staff and craft workers on-site during an outage, it is reasonable to conclude that there would be enough people available to take the necessary actions to clear the opening of the temporary services and replace the barrier.

The CLB does not define the duration of the flood.

The flood protection features consist of the following incorporated passive features: walls, floors, penetration seals, and internal conduit seals. The Emergency Cooling Tower Structure, Diesel Generator Building, and Emergency Pump Structure are flood protected to 137.5'. The Reactor Building structure is sealed to Elevation 135'. The Radwaste Building is flood protected to Elevation 135'.

Penetrations in the exterior walls are sealed to ensure leak tightness.

The flood protection features consist of the following incorporated active features: watertight doors, level switches indicating river level, valves, and sluice gates. Protection provided by these active features is as follows. The Diesel Generator Building, Emergency Pump Structure, and Reactor Building have watertight doors. Reactor building doors above Elevation 135' are weather stripped for leak tightness. Small amounts of water which might leak through the doors' weather stripping would not threaten operation of credited equipment. Valves in the Emergency Pump Structure prevent flood water from backing up to the roof of the pump structure, and a valve at the Diesel Generator Building prevents backflow through the Diesel Generator Building sump overflow drain line. The sluice gates will be closed when the river level reaches Elevation 113', and their closure is part of placing the Emergency Cooling Tower in service. The operation of the service water systems is then transferred from river supply to the on-site emergency reservoir. The isolation of the service water systems, from the normal heat sink, will be accomplished via procedures.

The turbine building will be allowed to flood to equalize the water level to avoid excessive unbalanced hydrostatic loads on the exterior walls.

Page 15

NTIF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 Procedure AO 28.2, "Response to High/Low River Level" (Reference 28) is entered and actions are initiated when river level is greater than or equal to 109.5', which is slightly higher than the high end of the normal elevation range of Conowingo Pond, which is 109.25'. Flood protection and mitigation actions are defined in the Flood Procedure SEA. As identified in Section 3.c of this report, six (6) reasonable simulations were performed to demonstrate that flood mitigation actions defined in SE-4 could be executed. A credited time for these actions is not defined. However, the time required to perform the actions was compared to a river level rate of rise of 1 ft/hr to assess whether or not the action could be performed without being impeded by the rising flood water.

Warnings for high river level leading to an external flood can come from either a high alarm on the intake canal level or notification to the PBAPS Main Control Room from any offsite agency that high river flows are expected. Notification from an off-site agency would be made via the following chain of communications. Personnel from Muddy Run dam or Conowingo dam would notify the Power Team or PJM (grid operators), who in turn would notify the Exelon Nuclear Duty Officer, who would notify PBAPS. Initial actions include contacting the Conowingo Control Room to verify actions are being taken to control river level. If river level continues to rise above 109.5' and is greater than or equal to 111' and river flow is greater than 600,000 cfs, and if not previously entered, the flood procedure, SE-4 is entered. If river level reaches 111' and river flow is predicted greater than 600,000 cfs, flood related shutdown actions are initiated. Reactors will be shut down to MODE 4 using procedure GP-3, "Normal Plant Shutdown" (Reference 30). At river level 112', the reactors are manually scrammed using procedure GPA, "Manual Reactor Scram" (Reference 31) and then cooled down to MODE 4. The gratings in the operating floor of the Circulating Water Pump Structure will allow water from the circulating bays to rise into the pump structure. At water level 113' , the circulating water pump system would trip. At river level 113', the Emergency Cooling Water System startup procedure is initiated. SE-4 contains other actions for providing flood protection that are initiated when the river elevation is predicted to be greater than 115'. These other actions performed via SE-4 that align with the flood protection measures defined in the ClB were executed as reasonable simulations, as identified in Section 3.c of this report.

For SE-4 procedure steps that require personnel to walk outside of the buildings to complete an action, it is assumed that adverse weather conditions (e.g., heavy rain and high winds and ice) exist simultaneous to the design basis flood. Adverse weather would increase the time required for activity completion because it would take longer for operators to walk outdoors, from building to building. But walking time is a small proportion of activity time, and adverse weather would not prevent an operator from completing any action.

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

The ClB does not credit room water level warning systems for protection from external flooding. The rooms important to safety that contain equipment required for safe shutdown are protected by the structures that house these SSCs. These structures include the Reactor Building, Diesel Generator Building, Emergency Pump Structure, and Emergency Cooling Tower Facility. These buildings are flood protected as identified in Section 4.b of this report and therefore form an external flood barrier to prevent flood waters from entering any rooms containing equipment important to safety. The rooms in the Diesel Generator Building and the ESW pump rooms contain water level indicators that provide an alarm to the Control Room. These level indicators and alarms are not features credited in the ClB for external flooding events, Page 16

NTTF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 but do provide defense in depth and a secondary notification of a flood condition at the site if the external flood barrier should fail.

It is noted that the Emergency Core Cooling System (ECCS) Pump Room water level indicators are not plant features credited in the licensing basis for protection from or mitigation of external flooding events. These features are designed for protection/mitigation from internal flooding events resulting from a pipe break in the ECCS pump suction piping.

The primary flood warning system comes from monitoring river level. There are six river water level indicators in the main control room providing indication from the Intake Canal side of each of the Circulating Water Traveling Screens. These level indicators continuously indicate river level, periodically are logged, and provide input to the plant monitoring system computer for high and low level alarms.

Procedure AO 28.2, "Response to High/Low River Level" would be entered when river level is greater than or equal to 109.5'. Procedure actions include contacting Conowingo and monitoring river flow, but TRM actions do not commence until a river elevation of 111' (References 34 and 35).

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 barriers were evaluated using the acceptance criteria developed as part of Requested Information Item l.h [in Enclosure 4 of the March 12, 2012, 50.54(f) letter]

Section 6 of NE112-07 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 n. Deficiencies must be reported to the NRC in the response to the 50.54(j) letter. "

As indicated in Section 3.d, inspection guidance was developed, supplementing NEI 12-07, to provide more specific criteria for judging acceptance. All observations that cannot be immediately judged as acceptable were entered into the site's Corrective Action Program (CAP) where an evaluation of the observation can be made.

Visual inspections of the external flood protection features were performed with the objective of comparing the observed condition of the feature to the acceptance criteria as defined in Section 6 of NEI 12-07 and the Supplemental Walkdown Inspection Guidance (Reference 29). This approach provided the basis for assessing the feature's ability to perform its intended external flood protection function and identifying conditions warranting entry into the corrective action program. Observations entered into the corrective action program are discussed in Section 4.f of this report.

The CLB defines that all structures required for safe shutdown have watertight doors and have waterproofing installed to Elevation 135'. Penetrations in the exterior walls are sealed to ensure leak tightness. With the exception of the features entered into the corrective action program (those listed in Table 4 in Section 5 of this reportL the inspections revealed that the features met the acceptance criteria.

Table 3 in Section 5 of this report lists the features that were immediately judged as acceptable via the visual inspections. Details of these acceptable features are as follows. The concrete walls and floors Page 17

NTTF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 identified as external flood barriers were inspected and found to have no signs of material degradation or cracks. The interior surfaces did not show signs of water intrusion or leakage such as stains or calcification.

As a result, it was determined that the walls and floors are effectively performing their flood protection function. Associated penetration seal material did not show any signs of degradation nor visible gaps or holes in the seal material. There was no evidence of water leakage from the penetrations. As a result, it was determined that the penetration seals are effectively performing their flood protection function. The Structures Monitoring Program ER-PB-450-1006 (Reference 21), provides periodic confirmation of the features' ability to perform its flood protection function. The examination criteria in this program match the acceptance criteria used during these walkdowns.

The watertight doors in the Diesel Generator Building, Emergency Pump Structure, Radwaste Building, and Reactor Building credited as flood protection features were inspected and found to meet the acceptance criteria. That is, the door hardware was in place and in satisfactory condition, and the seals were installed and showed no signs of degradation. Further, periodic inspection of the doors via the routine tests in the water tight door sur\ley RT-M-045-980-2 (Reference 25) provides reassurance that these features will continue to perform their flood protection function. The five (5) watertight Diesel Generator Equipment Doors are inspected periodically per the routine test in the "Water Tight Diesel Equipment Access Door Survey" RT-M-045-990-2 (Reference 26), which is performed every three years during the associated diesel generator preventative maintenance window. The most recent performance of this routine test was satisfactory revealing that all seals were in place and not degraded. Thus, based on the results of the latest routine test, it is concluded that these doors can perform their flood protection function.

The river water level instrumentation is available and capable of providing a warning of riSing river level.

TRM Section 3.7 requires that river water level indicator operability be verified by visual observation once every 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months . In addition, this instrumentation is periodically maintained by the preventive maintenance program. Re\liew of recent maintenance work on the valves in the Emergency Pump Structure (HV-O-28A-11443 and HV-O-28A-11444) and the valve at the Diesel Generator Building (HV-O-52-10152) that are positioned via steps in the flood procedure SEA confirmed they are in good working order (Reference 36).

The sluice gate motor operators were inspected and found to be in good condition without signs of degradation or corrosion. In addition, the sluice gate motor operators are periodically maintained by the preventive maintenance program. Therefore, these active features meet the acceptance criteria and are capable of performingtheirflood protection functions.

The reasonable simulations performed showed that credited procedures/actions could be accomplished before being impeded by rising flood waters. As mentioned previously, a flood level increase of 1 foot/hr was used to assess the ability to perform the actions. Six (6) simulations of activities, defined in flood procedure SE-4 were conducted. Refer to the simulations defined in Section 3.c of this report. The activities were timed, and in all cases the duration of the simulation showed that the activity could be completed prior to flood water riSing to the grade level. The material and equipment necessary to complete the activities was available. Adequate personnel resources would be available at the site during a flooding event to perform the activities in parallel.

The simulation determined that the time to place the Emergency Cooling Tower (ECT) in service to the point at which it is performing its design function of providing cooling to the Emergency Diesels and Primary Containment is 9S minutes. This part of the activity could be performed prior to the flood level reaching the plant grade of 115', because the activity is started when water level reaches 113' and CLB estimates a 1 foot per hour water rise.

The time to complete the Emergency Cooling Water startup procedure (SO 48.1.B) was 189 minutes, per the sequence of the controlled procedure revision during the simulation. The additional time, beyond 95 Page 18

NTTF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 minutes to put the ECT in service, was to close manually operated sluice gates (31 minutes); close manual loop isolation valves (30 minutes); and close two ESW valves in the RBCCW rooms (33 minutes). The manual sluice gates and manual loop isolation valves are redundant to motor operated components.

Closure of the ESW valves in the RBCCW rooms prevents ESW inventory loss in the event of a (corrosion sample skid) line break. Since these ESW valves are indoors, they have no impact on implementing the procedure prior to water reaching plant grade. Therefore the timeline, as the procedure was written, without counting the indoor procedure step, was 156 minutes, which is longer than the 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months available until water rises from 113' to 115'. IR 1435150 (reference 37) identified the time difference in the corrective action program, and PCRA's 1411311-01 and 901631-04 made enhancements to SEA and SO 48.1.B, respectively.

Based on enhancements to SO 48.B.l, this time is expected to reduce from 156 minutes to 110 minutes. An enhancement will reduce the time for putting the ECT in service from 95 minutes to 80 minutes by paralleling procedure tasks. An enhancement totally eliminates the sluice gates time constraint by moving this task up in the procedure. The closure of manual loop isolation valves is unchanged at 30 minutes, for a post-enhancement time of 110 (80 +30) minutes. This is a margin of 10 minutes under the 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months available until water rises from 113' to 115'.

For the actions required during simulations #3 and #4, the equipment operators are dispatched from the administration building directly to areas inside the Turbine Building to perform the procedure steps. As a result, these activities can be executed without the need to leave the plant buildings, and thus would not be impeded by any weather conditions related to the flooding event. For the other simulations that would require traversing across the plant grade, it is expected that weather conditions could slow the travel time but would not prevent the equipment operators from reaching their destination and performing the required actions prior to the flood waters reaching plant grade. The durations to perform the actions, as timed during the simulations, are such that additional time would remain prior to flood water reaching plant grade. This additional time can be used to account for any delays that may be caused by adverse weather conditions. Simulation #1 was performed in 18 minutes leaving 222 minutes until flood water would reach plant grade. Simulation #5 was performed in 31 minutes leaving 29 minutes until flood water would reach plant grade. The Emergency Cooling Tower was placed in service such that it would perform its design function in 95 minutes leaving 25 minutes until flood water would reach plant grade. For all simulations, sufficient additional time exists after completion of the actions such that flood water would not have reached the plant grade. This shows that delays due to adverse weather conditions could occur and the actions could still be completed prior to being impeded by flood waters.

The Licensed Operators are trained to procedure SE-4 during their initial training and then are retrained to the procedure every 2 years. The equipment operators (EO) are trained to procedure SE-4 during their initial training. IR 1411382 has been created for the Curriculum Review Committee (CRC) to consider SE-4 for EO Continuing Training.

The manholes in the yard were not inspected because they are not external flood protection features. The conduits from the manholes to the equipment in safety related structures are internally sealed. The internal seal is an external flood protection feature. Further, all rooms containing safety related SSCs below the flood level were walked down, so any signs of external water ingress originating from a manhole and flowing down the outside of a conduit and into a building would have been seen.

Page 19

NTTF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5,2012

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 l.j lin Enclosure 4 of the March 12, 2012, 50.54(f) letter}, including actions taken in response to the peer review.

The selection of the walkdown team considered site familiarity and diversity of disciplines. The walkdown team consisted of a member from the mechanical, electrical and civil diSciplines and one member with experience on performing plant mod ifications. There were a total of four individuals on the Peach Bottom walkdown team.

All team members participated in eight hours of training conducted by Exelon that reviewed the content of the Reference 2, NEI 12-07 guidelines. Team members were required to perform a review of the NEI 12-07 document prior to attending the training in an effort to have increased engagement during the training sessions.

All team members completed the NANTEL Generic Flood Protection Awareness and Generic Radiation Worker Training courses. All team members also passed the NANTEL Generic Verification Walkdowns of Plant Flood Protection Features test. Documentation was obtained from INPO and provided to the site to demonstrate that the walkdown team members had completed the required training.

Pre-walk bys of many areas to be inspected were conducted to facilitate scope definition prior to any inspections being performed. During the initial walk bys, team members practiced performing visual inspections to the acceptance criteria for various types of features. These exercises lead to discussions and approaches to be prepared for effective walkdown inspections when they were scheduled to be performed.

The walkdowns were conducted by teams of two ENERCON employees and one Exelon delegated Task Manager (minimum). Exelon Operations and Maintenance supplemented the walkdown team as required.

During the visual inspection each flood protection feature was identified by each member of the team to ensure that data being collected was associated with the same plant feature. The walkdowns were conducted following the guidance of NEI 12-07 and no exceptions were taken to this guidance. A peer review of the walkdown results documented on the walkdown record forms, including those documenting reasonable simulations, was performed.

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 descri ption 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, flOperability Conditions Adverse to Quality or Safety," including entering the condition in the corrective action program.

Observations made during the visual inspections not immediately judged as acceptable were entered into the Corrective Action Program (CAP). The features contained in this category are listed in Table 4 in Section 5 of this report. Table 4 shows that component operability has been demonstrated for these features. The table also identifies the actions planned to resolve the identified conditions.

Page 20

NTTF Recommendation 2.3 (Walkdowns); Flooding Exelon Corporation November 5, 2012 Features classified as restricted access are listed in Table 5 in Section 5 of this report. Table 5 provides the reason for being classified as restricted access.

There are two blockouts in the Restricted table. All other items in the Restricted table are internal conduit seals. The Restricted items will be inspected in accordance with site procedures and processes that minimize operational and personnel risk.

Reasonable assurance that these features are available and capable of performing their external flood protection or mitigation function for the full duration of the flood condition was based on design-quality, component-level configuration documentation in the Component Record List (CRL).

The CRL documents the internal conduit seals were installed per drawing E-1315, section 1.2.2.1, which indicates external flood seals are installed and inspected per Specification NE-075. NE-075 Section 7.5.2 defines the performance criteria and seal material requirements. Since original installation, if a seal is modified or re-worked, a penetration detail (PO) series drawing is specified, and the CRL is updated with this information. PO drawings provide cross-sections and specifications, augmenting NE-07S.

Features classified as inaccessible are listed in Table 6 in Section 5 of this report. The following discussions provide the basis for the reasonable assurance that the features are available and able to perform their credited external flood protection functions.

Some penetration seals in the Diesel Generator Building are classified as inaccessible due to a personnel safety hazard and a risk to plant operations. These penetrations enter, from beneath, into MCCs that would need to be removed out of service entirely, and disassembled, in order to inspect. Total de-energization of the MCCs is not feasible because the diesel generators are shared between both units and removal from service to perform inspections does not coincide with either unit outage. Routine maintenance is performed on MCC buckets individually, but the entire MCC remains energized. Therefore the penetration seal inspection does not fit into any outage window.

Penetration ECT-114-829-3001 in the Emergency Cooling Tower Structure is classified as inaccessible because it is underground.

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 lithe safety consequences of a flooding event may increase sharply with a small increase in the flooding level". As indicated in Sections 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 Sections 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.

Page 21

NTTF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 APM information was collected during the walkdowns in accordance with guidance provided in NEI 12-07 and the final resolution to FAQ-006. APM was collected to primarily support 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 APM and other information, such as the specific SSCs that are subjected to flooding and the potential availability of other systems to mitigate the risk.

Since the walkdowns were completed prior to the final resolution of FAQ-006 (September 13, 2012), APM information was collected and documented on the Walkdown Record Form using the "old approach", that is, a simple measurement of the difference between the licensing basis flood height and the flood height at which water could affect an SSC important to safety.

h. Requested Information Item 2(b) - 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.

During the review and performance of the reasonable simulations of activities defined in Flood Procedure SE-4, enhancements, which improve the station's response to a flood, were identified (PCRA 1411311-01).

The enhancements consist of items such as annotating those procedure steps that are credited in the current licensing basis so that they can be prioritized, referencing a list of watertight doors to be checked, and reordering procedure steps so that actions can be performed in parallel to gain margin. These changes have since been incorporated into the procedure.

Additionally, IR 1411382 was written to request that the equipment operator curriculum review committee consider adding SE-4 training to the continuing training topics for equipment operators. Currently, equipment operators only have initial training on SE-4. Periodic training would better prepare the station staff to respond to a flooding event.

During the review and performance of the reasonable simulations of activities defined in Emergency Cooling Water System Startup Procedure SO 48.1.B, enhancements, which improve the station's response to a flood, were identified (PCRA 901631-04). The enhancements consist of items such as reordering procedure steps so that actions can be performed in parallel to gain margin and directing performance of certain manual actions in parallel with other actions. These changes have since been incorporated into the procedure.

This section of the report includes six (6) tables that provide the results of the walkdowns. Table #1 provides a summary of the number and type of features included in the walkdown scope. A total of 1,409 features were included in the scope of this effort.

Table #2 summarizes the reasonable simulations performed to mimic actions in Flood Procedure SE-4. The results show the actions that protect equipment required for safe shutdown align with the CLB external flood protection, and can be performed in sufficient time such that the rising flood waters would not Page 22

NTTF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 prevent the actions from being accomplished. In addition, enhancements to Flood Procedure SE-4 to improve station flood response have been identified and incorporated into the procedure.

The results of the visual inspections during the flooding walkdowns showed that 976 features meet the NEI 12-07 acceptance criteria and are thus capable of performing their flood protection function. Table #3 provides this list of features that were immediately judged to be acceptable.

Table #4 provides the list of features that did not meet the acceptance criteria as observed during the walkdowns. 27 features fall into this category. The table identifies that these features have been determined to be operable, and provides the tracking mechanism for resolution of the identified conditions.

Table 5 provides the list of features classified as restricted access. Detailed discussion of restricted access internal conduit seals is provided in section 4.f of this report. 300 features are classified as restricted access.

Table #6 lists 106 features that are classified as inaccessible. The reason for this classification is provided along with a summary of the reasonable assurance that has been provided to ensure the flood protection feature can perform its function. Detailed discussions of reasonable assurance are provided in section 4,f of this report.

Table #1: SUmmary - Features Included in the Walkdown Scope Feature Type Total Number Passive - Incorporated 1375 Passive - Temporary 0 Active -Incorporated 34 Active - Temporary a Table #a: Reasonable Simulation R.S.# Description Purpose Prevent flood water from backing up to roof of pump 1 Valve Positioning in Pump Structure structure 2 Closing/securing watertight doors Maintains the external flood boundary Plug radioactive lab waste floor drain in Prevent overflowing a tank in the Radwaste Building with 3

the old Hot Chemistry Lab flood waterfrom the Turbine Building Prevent overwhelming the Radwaste Building with Open Turbine Building Sump Pump 4 flood water since the affected sump pumps direct Breakers water to the Radwaste Building Close Diesel Generator Building Oily Prevent backflow through the Diesel Generator Building 5

Waste Valve and Insert 4/1 Plug sump overflow drain line.

Transfer of the service water system from river supply to Activation of Emergency Cooling Water 6 the on-site emergency reservoir as described in the System flooding CLB Page 23

NTTF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 Table II: I~ FloodillJ Features Meeting Acceptance Criteria Featum Immediately Judged lIS Aecaptable No. Feature 1.0. Number Description Passive!Active Incorporated/Temporary 88' /91' 1102' RadVIIllSte Bulldmg, Reactor Building. Turbine Building ~ Passive Features 1 RB2-091-001-3001 4"SLV w/l" P, STL. PLATE ASSLV Passive Incorporated 2 RB2*091-001-3002 4"SLVw/l"P, STL. PLATE ASSLV Passive Incorporated 3 RB2*091-001*3003 4"SLVw/l"P, STL. PLATE ASSLV Passive - Incorporated 4 RB2-091*001-3004 4" SLVw/l" P. STL. PLATE AS SLY Passive Incorporated 5 RS2-091-001*300S 12" CSW/6" P Passive - Incorporated 6 RB2*091*001*3006 10" ell W/6" P Passive - Incorporated 7 RB2*091*001*Slab Slab Passive Incorporated 20" DIA. CORE BORE FOR 16" DIA.

8 RB2-091-001-6001 Passive Incorporated PIPE 9 RB2-091-002*East Wall East Wall Passive Incorporated 10 RB2*091-002-South Wall South Wall Passive Incorporated 11 RB2-091-002-West Wall West Wall Passive Incorporated 12 RB2-091-002*Slab Slab Passive - Incorporated 13 RB2*091-003-West Wall West Wall Passive* Incorporated 14 RB2-091*003-Slab Slab Passive* Incorporated 15 RB2-091-004-West Wall West Wall Passive Incorporated 16 RB2-091-004-Slab Slab Passive Incorporated 17 RB2-091-00S-West Wall West Wall Passive Incorporated 18 RB2-091-005*Slab Slab Passive - Incorporated 19 RW2-088-006*Floo r Slab Passive - Incorporated 20 RW2-088-006-West Wall West Wall Passive - Incorporated 21 RW2*088-007 -Floo r Slab Passive - Incorporated Page 24

NTTF Recommendation 2.3 (Walkdowns); Flooding Exelon Corporation November 5, 2012 Table 13: Impeded Flooding Features Meeting Ac.:epmnce Criteria Features Immediately Judged liS Ai:cepmble No. Feature 1.0. Number Description Passive/Active Incorporated/Temporary 22 RW2*088*00S-2001 6" C #ZD2l014 w/O.Z. BUSHING Passive - Incorporated 23 RW2-08S*00S-2002 16" SLY wI 14" FIBER INS. P Passive - Incorporated 24 RW2*0SS-008-2003 24" SLY w/lS" FIBER INS. P Passive Incorporated 25 RW2*0SS-00S*2004 24" SLY w/1S" FIBER INS. P Passive Incorporated 26 RW2*0SS*00S-2005 24" SLY w/lS" FIBER INS. P Passive -Incorporated 27 RW2-0SS*008-2006 4" SlVw/2" P Passive -Incorporated 28 RW2-0SS-008-2007 2" CBw/1" P Passive - Incorporated 29 RW2-08S*00S-200S 2" CBw/!" P Passive Incorporated 30 RW2-0SS*008-2009 4" SLY w/2" P Passive - Incorporated 31 RW2-0SS*00S-201O 6" C OE w/PG w/o CABLE Passive* Incorporated 32 RW2-0SS*00S*2011 8" SLY w/4" P Passive Incorporated 33 RWZ*OSS-00S-2012 14" SLY w/10" P Passive - Incorporated 34 RWZ*OS8-00S-2013 14" SLY w/6" INSUl P Passive -Incorporated 35 RW2-0S8-008-2014 8" SLVw/4" P Passive Incorporated 36 RW2-088-00S-201S 22" SLY w/1S" INS. P Passive - Incorporated 37 RW2-0SS-00S-2016 7" SLY w/3" P Passive - Incorporated 3S RW2-08S-008-2017 4" SLVw/3" P Passive - Incorporated 39 RW2-088-008-2018 6" SlVw/3" P Passive Incorporated 40 RW2-0S8-008-2019 5" SLY Passive - Incorporated 41 RW2-088-008-2019A 2" P Passive - Incorporated 42 RW2-0S8-008-2020 4"X6" IT Passive - Incorporated 43 RW2-0SS*008-2021 12" SLY w/10" INS. P Passive - Incorporated 44 RW2-088-008-2022 1" C Passive - Incorporated Page 25

NTIF Recommendation 2.3 (Walkdowns); Flooding Exelon Corporation November 5, 2012 Tabla 113: Inspected Flooding Features Meeting Acteptanee CriterIa Feat\lteslrnmedlately Judged "Acceptable No. Feature 1.0. Number Description Passive!Active Incorporated/Temporary 45 RW2-088-oo8-2023 %/C Passive - Incorporated 46 RW2-088-oo8-2024 3" CB WI (2) 1/2" P Passive - Incorporated 47 RW2-088-008-East Wall East Wall Passive - Incorporated 48 RW2-088-008-Floor Slab Passive - Incorporated 49 RB2-091-009-East Wall East Wall Passive - Incorporated 50 RB2-091-009-Floor Slab Passive - Incorporated 51 RB2-091-010*Floor Slab Passive* Incorporated 52 RB2-091-011-East Wall East Wall Passive - Incorporated 53 RBZ*091-011-Floor Slab Passive - Incorporated 54 RB2-091-012-South Wall South Wall Passive - Incorporated 5S RB2-091-012-Floor Slab Passive Incorporated 56 TB2-102-016-4001 6" C #ZA2L001 Passive - Incorporated 57 TB2-102-016-4oo2 6" C #ZA2L004 Passive - Incorporated 58 TB2-102-016-4003 6" C OE w/PG wlo CABLE Passive Incorporated 59 TB2-102-016-4004 8" CB w/3" INS. P Passive Incorporated 60 TB2-102-016-4005 6" C ItZD2L014 w/O.Z. BUSHING Passive - Incorporated 61 TB2-102-016-4006 6" C OE w/PG wlo CABLE Passive - Incorporated 62 TB2-102-016-4007 6" C ItZC2L010 w/O.Z. BUSHING Passive - Incorporated 63 TB2-102-016-4008 6" P Passive - Incorporated 64 1B2 -102 -016-4009 1" C Passive - Incorporated 65 1B2-102-016-401O %" C (EYS FTG. A-SIDE) Passive Incorporated 66 1B2-102-016-4011 4"x 8" IT Passive - Incorporated 6" C #ZB2L012 w/O.Z. BUSHING (A-67 1B2-102-o16-4012 Passive - Incorporated SIDE)

Page 26

NTTF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 lable '3: Inspected fIoodlftl Ftaatufe5 Mli!li!tiftlAueptance Criteria Features Immediately Jlldged as Acceptable No. Feature I.D. Number Description PassivelActive Incorporated!Temporary 68 TB2-102-016*4013 6" (OE w/PG wlo (ABLE Passive Incorporated 69 TB2*102-016*4014 6" (ltZ82L013 Passive Incorporated 70 TB2*102*016*4015 6" (ltZA38152 Passive* Incorporated 71 TB(*091*017*4001 6" (ItZD2l016 Passive Incorporated 72 TB(*091*017-4002 2" (ltZP445 Passive Incorporated 73 T8(*091-017-4003 3" SlV Passive* Incorporated 74 TB(*091-017-4004 8" x 20" OVAL SLV Passive* Incorporated 75 TB(*091-017-4005 10" SlV w/6" P Passive Incorporated 76 TB(*091*017-400SA 2" P Passive Incorporated 77 TB(*091-017*4oo5B 2" P Passive* Incorporated 78 TB(*091-017-4006 8" x 15" OVAL SlV w/6" P & 4" P Passive* Incorporated 79 TB(*091-017-4007 3" SLV w/1 );," (U P Passive* Incorporated 80 TB(*091-017-4007A 2" P Passive* Incorporated 81 TB(*091-017 -4007B 2" P Passive* Incorporated 82 TB(*091-017-4008 %C Passive Incorporated 83 TB(*091-017-4009 %,"C Passive Incorporated 84 TB(*091-017-401O 4" SlVw/2" P Passive* Incorporated 85 TB(-091-017-4011 6" (DE Passive - Incorporated 86 TB(*091-017-4012 6" (DE Passive - Incorporated 87 TB(*091-017-4013 6" C OE (C OE USED AS SlV) Passive - Incorporated 88 TBC*091-017 -4014 6"COE Passive* Incorporated 89 TBC*091-017-4019A 2" P Passive - Incorporated 90 TBC*091-017-4015 8" SlV w/(2) 1 );," P Passive* Incorporated Page 27

NTTF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 Table.a: I~ Floodlnl Features MeetIng Acceptance Criteria Featul'e$lmlnfldlate!y Judged as Aa:eptable No. Fl!ature I.D. Number Description Passive/Active Incorporated/Temporary 91 TBC-091-017-4018 10" SlV w/ 6" 55 P Passive - Incorporated 92 TBC-091-017-4021 4" SLY w/2" INS. P Passive - Incorporated 93 TBC-091*017-4022 3')( 1'5" BO Passive* Incorporated 94 TBC-091-017-4023 10" SLY w/6" P Passive - Incorporated 95 TBC-091-017-4023A 2" P Passive - Incorporated 96 TBC-091-017-4024 8"SLVw/4" P Passive - Incorporated 97 TBC-091-017-4025 8" SLVw/4" P Passive Incorporated 98 TBC-091-017-4026 8" SLVw/4" P Passive - Incorporated 99 TBC-091-017-4027 1'-6" x 2' BO Passive Incorporated 100 TBC-091-017 -4028 8" SLVw/4" P Passive - Incorporated 101 TBC-091-017-4028A 2" P Passive Incorporated 102 TBC-091-017-4028B 2" P Passive Incorporated 103 TBC-091-017-4029 RADWASTE GENERAL ACCESS AREA Passive - Incorporated 104 TBC-091-017-4029A 2" P Passive -Incorporated 105 TBC-091-017-4029B 20" SLVw/18" HVAC Passive - Incorporated 106 TBC-091-017-West Wall West Wall Passive - Incorporated 107 RWC-091-024-Floor Slab Passive -Incorporated 108 RWC-091-025-Floor Slab Passive -Incorporated 109 RWC-091-026-Floor Slab Passive Incorporated 110 RWC*091.Q27-Floor Slab Passive -Incorporated 111 RWC-091-028-Floor Slab Passive -Incorporated 112 RWC-091-029-Floor Slab Passive - Incorporated 113 RWC-091-030-Floor Slab Passive -Incorporated Page 28

NTIF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 TaliII'! 113: 1nspec:ted flooding Features Meeting A~m:e Criteria

~Immedlately Judled _Acceptable No. Feature 1.0. Number Description PassivelActive Incorporated/Temporary 114 RWC-091-031-Floor Slab Passive Incorporated 115 RWC-091-032-Floor slab Passive Incorporated 116 RWC-091-033-Floor Slab Passive Incorporated 117 RWC-091-033-West Wall West Wall Passive - Incorporated 118 RWC-091-034-Floor Slab Passive Incorporated 119 RWC-091-034-We5t Wall West Wall Passive - Incorporated 120 RB3-091-037-1001 10" CB w/6" P 8 X" HUB Passive - Incorporated 121 RB3-091-037-2001 8" CBw/6" P Passive Incorporated 122 RB3-091-037-2002 4" EMB. RECEPTACLE Passive - Incorporated 123 RB3-091-037-Z003 4" EMB. RECEPTACLE Passive Incorporated 124 RB3-091-037-2004 4" EMB. RECEPTACLE Passive - Incorporated 125 RB3-091-037-Z00S 2" x 4" WALL RECEPTACLE Passive Incorporated 126 RB3-091-037-2006 %"C Passive Incorporated 127 RB3-091-037-North Wall North Wall Passive - Incorporated 128 RB3-091-037-West Wall West Wall Passive Incorporated 129 RB3-091-03 7-Floor Slab Passive - Incorporated 20" DIA. CORE BORE FOR 16" DIA.

130 RB3-091-037-6001 Passive Incorporated PIPE 131 RB3-091-039-West Wall West Wall PaSSive Incorporated 132 RB3-091-039-Floor Slab Passive Incorporated 133 RB3-091-040-West Wall West Wall Passive Incorporated 134 RB3-091-040-Floor Slab Passive - Incorporated 135 RB3-091-041-East Wall East Wall Passive - Incorporated 136 RB3-091-041-North Wall NorthWaU PaSSive - Incorporated Page 29

NlTF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 Table 13: Inspetted FIoodlne Features Meetlne Acceptance Criteria features Immediately Judged as Aeceptable No. Feature I.D. Number Description PassivelActive IncorporatedfTernporary 137 RB3-091-041-West Wall West Wall Passive - Incorporated 138 RB3-091-041-Floor Slab Passive - Incorporated 139 RB3-091-042-North Wall North Wall Passive - Incorporated 140 RB3-091-042-Floor Slab Passive Incorporated 141 RB3-091-043-2001 10" SLV wfTEMP CABLE Passive Incorporated 2" P 142 Passive - Incorporated RB3-091-043-2oo1A 143 RB3-091-043-2oo2 4" C tlZB3LOO7 Passive Incorporated 144 RB3-091-043-2oo3 6" C OE w/PG w/o CABLE Passive -Incorporated 4" EMB. LIGHT RECEPTACLE (WHITE 145 RB3-091-043-2004 Passive - Incorporated LIGHT) 146 RB3-091-043-2005 NOT IN PIMS Passive Incorporated 147 RB3-091-043-East Wall East Wall Passive - Incorporated 148 RB3-091-043-Floor Slab Passive - Incorporated 149 RB3-091-044-Floor Slab Passive - Incorporated 150 RB3-091-044-2001 4" C tlZC3L012 Passive - Incorporated 151 RB3-091-044-2002 6" C OE w/PG w/o CABLE Passive - Incorporated 152 RB3-091-044-East Wall East Wall Passive - Incorporated 153 RB3-091-045-Floor Slab Passive - Incorporated 154 RW3-088-046-2001 2" SLV w/PG Passive - Incorporated 155 RW3-088-046-2002 12" SLV w/8" INS. P Passive - Incorporated 156 RW3-088-046-2003 6" SLVw/4" P Passive Incorporated 157 RW3-088-046-2004 6" SLVw/4" P Passive - Incorporated 158 RW3-088-046-2005 6" SLVw/4" P Passive -Incorporated 159 RW3-088-046-2006 24" SlV w/20" INS. P Passive - Incorporated Page 30

NTTF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 Table #3: ln~ Flooding featurE!$ Meeting Acceptance CrIteria Featureslmrnedla1ely Judged all Acceptable No. Feature 1.0. Number Description Passive/Active Incorporated/Temporary 160 RW3-088-046-2007 3" SlV w/IZ) }S" PIPES Passive Incorporated 161 RW3-088-046-2008 8" xl' 4" OVAL SlV w/(l) 4" INS. P Passive Incorporated 162 RW3-088-046-Z009 12" SLV w/10" P Passive Incorporated 163 RW3-088-046-Z010 6" SLV w/O.Z. BUSHING (B-SIDE) Passive* Incorporated 164 RW3-088-046-2011 6" C OE w/PG w/o CABLE Passive Incorporated 165 RW3-088-046-2012 18" SLV w/l4" INS. P Passive Incorporated 166 RW3-088-046-2013 22" SLV w/18" INS. P Passive - Incorporated 167 RW3-088-046-2014 20" SLV w/l8" INS. P Passive Incorporated 168 RW3-088-046-2015 2" SlV w/l" P Passive - Incorporated 169 RW3-088-046-2016 2" SLVw/l" P Passive Incorporated 170 RW3-088-046-2017 20" SLV w/18" INS. P Passive Incorporated 171 RW3-088-046-2018 2"P Passive Incorporated 172 RW3-088-046-2019 3" SlVw/2" P Passive* Incorporated 173 RW3-088-046-2020 6" C OE w/PG wlo CABLE Passive* Incorporated 174 RW3-088-046-2021 3" CB W/ (2) 1/2" P Passive - Incorporated 175 RW3-088-046-East Wall East Wall Passive - Incorporated 176 RW3-088-046-Floor Slab Passive - Incorporated 177 RW3-088-048-West Wall West Wall Passive - Incorporated 4" C #ZC3L010 w/CONDUIT SEALING 178 TB3-102-053-4001 Passive - Incorporated BUSHING 6" C IIZB3L013 w/CONDUIT SEALING 179 TB3-102-053-4002 Passive Incorporated BUSHING 4" C #ZD3LOOl w/CONDUIT SEALING 180 TB3-102-053-4003 Passive Incorporated BUSHING 181 RWC-108-l4l-4001 4'0" X 4'0" B.D. Passive - Incorporated 182 RWC-I08-141-4002 20" SLV W/l2" PRoof DRN Passive - Incorporated Page 31

NTTF Recommendation 2.3 {Walkdowns}: Flooding Exelon Corporation November 5, 2012 Table IS; Inspected floodll'll Features Meetll'll Acceptance Criteria Features Immediately Judged liS Acceptable No. Feature 1.0. Number Description Passive/Active Incorporated/Temporary 183 RWC*108-141*4003 10" SLV W/6" P F.5. Passive . Incorporated 184 RWC*I08-141*4004 8" CSW/s" P Passive . Incorporated 185 RWC*I08*141*4005 36" 5BGT Exhaust Duct Passive Incorporated 186 RB2*091*ST18*East Wall East Wall Passive* Incorporated 187 RB2-091-ST18-Floor Slab Passive Incorporated 188 RB2*091-ST18-South Wall South Wall Passive Incorporated 189 RB2-091-ST19-East Wall East Wall Passive Incorporated 190 RB2*091-EL19*East Wall East Wall Passive - Incorporated 191 RB3*091-ST22-2001 4" EMB. LIGHT RECEPTACLE Passive* Incorporated 192 RB3-091-EL22-East Wall East Wall Passive* Incorporated 193 RB3-091-ST22*East Wall East Wall Passive Incorporated 194 RB3*091*ST23-2001 4" C #ZD3L004 Passive* Incorporated 195 RB3*091*ST23-2002 7" SLV w/LEAD PG (B-SIDE) Passive - Incorporated 196 RB3*091-ST23-East Wall East Wall Passive - Incorporated 197 RB3-091-ST23-North Wall North Wall Passive - Incorporated 198 RB3-091-ST23-Floor Slab Passive - Incorporated 116' RadwasteBulldlng, Reactor Building, Turbtne Building. Passive Features 199 H33 Hatch Passive - Incorporated 200 H34 Hatch Passive - Incorporated 201 RB2-116-101*2001 3" COL Passive -Incorporated 202 RB2-116-101-2002 3"C.OE Passive -Incorporated 203 RB2-116-101-2003 3" CO.E. Passive -Incorporated 204 RB2-116-101-East Wall East Wall Passive - Incorpo rated Page 32

NTTF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 Table ta: Inspeded Flooding Features Meeting Awiptance Criteria Features Immediately Judged as Acceptable No. Feature I.D. Number Description Passive!Active Incorporated/Temporary 205 RB2-116-101-South Wall South Wall Passive Incorporated 206 RB2-116-101-West Wall West Wall Passive - Incorporated 207 RB2-116-102-West Wall West Wall Passive Incorporated 208 H17 Hatch Passive* Incorporated 209 RB2-116-103-4001A 2" P Passive* Incorporated 210 RB2-116-103-West Wall West Wall Passive Incorporated 211 HIS Hatch Passive Incorporated 212 H16 Hatch Passive Incorporated 213 H18 Hatch Passive Incorporated 214 RW2-116-104-4001 6" C#2LOS4 Passive Incorporated 215 RW2-116-104-4002 6" C#2L056 Passive* Incorporated 216 RW2-116-104-4003 6" C #2L058 Passive - Incorporated 217 RW2-116-104-4004 6" C#2L061 (EMBEDDED) Passive - Incorporated 218 RW2-116-104-4005 6" C #2l063 (EMBEDDED) Passive Incorporated 219 RW2-116-104-4006 6" C #2L060 (EMBEDDED) Passive Incorporated 220 RW2-116-104-4007 6" C #2L062 (EMBEDDED) Passive - Incorporated 221 RW2-116-104-4008 6" C#2L059 Passive - Incorporated 222 RW2-116-104-4009 6" C #2L057 Passive - Incorporated 223 RW2-116-104-401O 6" C #2LOS5 Passive* Incorporated 224 RW2-116-104-4012 6" C #2L064 (EMBEDDED) Passive Incorporated 225 RW2-116-104-4013 6" C#2L066 (EMBEDDED) Passive Incorporated 226 RW2-116-104-4014 6" C #2L068 (EMBEDDED) Passive - Incorporated 227 RW2-116-104-4015 8" C#2L069 Passive - Incorporated Page 33

NTIF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 Table #3: In$~ FIoodlrtg Features Meetirtg AcceptanceCriterilil Features Immediately Judged 11$ Acceptable No. Feature 1.0. Number Description Passive/Active Incorporated/Temporary 228 RW2-116-104-4016 6" C 1i2L067 (EMBEDDED) Passive - Incorporated 229 RW2-116-104-4017 6" C 1i2L065 (EMBEDDED) Passive Incorporated 230 RW2-116-104-West Wall West Wall Passive Incorporated 231 H19 Hatch Passive Incorporated 232 RW2-116-lOS-2001 6" CB w/Al FLEX CONDUIT Passive Incorporated 233 RW2-116-105-2002 2" CB Passive Incorporated 234 RW2-116-105-2003 6" C #2B226 (2L061 TO J188) Passive - Incorporated 235 RW2-116-105-2004 6" C #2B225 (2L063 TO J188) Passive - Incorporated 236 RW2-116-10S-2005 6" C #2B228 (2L060 TO J188) Passive - Incorporated 237 RW2-116-10S-2006 6" C #2B229 (2l062 TO J188) Passive - Incorporated 238 RW2-116-10S-2007 2" C Passive Incorporated 239 RW2-116-10S-2008 2" C Passive - Incorporated 240 RW2-116-105-2009 1" C Passive Incorporated 241 RW2-116-lOS-2010 1" C Passive Incorporated 242 RW2-U6-105-2011 2" C OE #2M720 Passive - Incorporated 243 RW2-116-lOS-2012 2" C OE #2M710 Passive - Incorporated 244 RWH16-105-Z013 2" C OE #2M70S Passive - Incorporated 245 RW2-116-10S-2014 2" C OE #2M697 Passive - Incorporated 246 RW2-116-105-201S 4" SLV w/2" CU P Passive Incorporated 247 RW2-116-lOS-2016 3" SLY w/l" CU P Passive - Incorporated 248 RW2-116-105-2017 5" SLY w/3" CU P Passive Incorporated 249 RW2-116-105-2018 4" SLY w/3" CU P Passive - Incorporated D

250 RW2-116-105-2019 6" SLY w/3 P & ALS Passive - Incorporated Page 34

NTTF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 Table :113: tns~ flooding Features Meeting Atteptance Criteria Features Immediately Judged as Acceptable

~.

No. Feature 1.0. Number Description Passive/Active Incorporated/Temporary 251 RW2*116*105*2020 5" SlVw/2" P Passive Incorporated 252 RW2*116-105*2021 4" SLV w/2" CU P Passive* Incorporated 253 RW2*116*10S*2022 2 v," C OE w/PG w/o CABLE Passive* Incorporated 254 RW2*116*105*2023 2 v," C OE w/PG w/o CABLE Passive* Incorporated 255 RW2*116*105*2024 2" C OE w/PG w/o CABLE Passive* Incorporated 256 RW2*116*105*2024A 11/2" C 2B288 Passive* Incorporated 257 RW2*116*105*2025 2 v," C OE w/PG w/o CABLE Passive Incorporated 258 RW2*116*105*2026 2" CB Passive Incorporated 259 RW2*116*105*2027 1 y," CB, y," TUBING (1) TUBE Passive* Incorporated 260 RW2*116*105*2028 3" CB w/1" 5.5. P Passive Incorporated 261 RW2*116*105*2030 7" CB Passive* Incorporated 262 RW2*116*105*4018 16" x 8" B.O. Passive Incorporated 263 RW2*116*105*4019 12" INSUL P ESW RETURN Passive Incorporated 264 RW2*116*105-East Wall East Wall Passive Incorporated 265 RW2*116*105*West Wall West Wall Passive* Incorporated 266 RW2*116-105*2029 SEISMIC GAP Passive* Incorporated 267 RB2*116-107*2001 1" C Passive* Incorporated 268 RB2-116-107-2002 8" CB w/CO*X & AlS LINES Passive* Incorporated 269 RB2*116*107*2003 l' x l' BO Passive* Incorporated 270 RB2*116*107*2004 Iv,"C Passive* Incorporated 271 RB2*116-107*East Wall East Wall Passive* Incorporated 272 RB2*116-108*200l 12" SL V W /6" INSUL P Passive - Incorporated REACTOR BUILDING PENETRATION 273 RB2*116*108-2006 Passive - Incorporated SEAL Page 35

NTTF Recommendation 2.3 {Walkdowns}: Flooding Exelon Corporation November 5, 2012 Table 13~ Inspected Flooding FeltIIn!$ Meetln" Acce,ta~ Criteria features Immediately Judpd as Aci1eptable No. Feature 1.0. Number Description Passive/Active Incorporated/Temporary 274 RB2-116-108-2oo7 6"SlVw/2W'P PaSSive Incorporated 275 RB2-116-108-2008 4" SlVw/2" P Passive Incorporated 3" CB w/1" FLEX ALS & (4) v," AlS &

276 RB2-116*108-2009 Passive Incorporated (1) 3/8" ALS (TEMP. WElDING CABLE) 277 RB2-116-108'2010 2" CB PaSSive Incorporated 6'0" x TO" B.O. w/(3) 2" CABLES CUT 278 RB2-116-108-3001 PaSSive Incorporated OFF 2" P 279 Passive Incorporated RB2-116-108-3OO1A 2" P 280 Passive Incorporated RB2-116-108-3OO1B 281 RB2-116-108-East Wall East Wall Passive Incorporated 282 RB2-116-108-South Wall South Wall Passive

Incorporated 283 TBC-116-126-4001 l' x l' BO PaSSive Incorporated 284 TBC-116-126-4001A 2" P Passive -Incorporated 285 T8C-116-126-4oo1B 2" P Passive Incorporated 286 TBC-116-126-4004 2" C OE wlo PG wlo CABLE Passive Incorporated 287 TBC-116-126-4005 1"C Passive* Incorporated 288 TBC-116-126-4006 1" C Passive* Incorporated 289 TBC-116-126-4007 2"COE Passive* Incorporated 290 TBC-116-126-4oo8 2" C w/CABLES Passive Incorporated 291 TBC-116-126-4009 2" C OE w/PG wlo CABLE Passive* Incorporated 292 TBC-116-126-4010 2" C OE w/PG w/o CABLE PaSSive Incorporated 293 TBC-116-126-4011 5'9" x 2'10" BO w/ALS CABLES Passive* Incorporated 294 TBC-116-126-4011A 2" P Passive* Incorporated 295 TBC-116-126'40118 2" P Passive* Incorporated 296 TBC-116-126-4011C 2" P Passive Incorporated Page 36

NTTF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November S, 2012 Table .a: Inspected Aoodin8 features Meetil1l Acceptant(! Criteria fUture$lmmedlate!y Judged as Acceptable No. Feature 1.0. Number Description Passive/Active Incorporated/Temporary 297 TBC-116-12~4011D 2" P Passive - Incorporated 298 TBC-116-126-4011E 2" P Passive - Incorporated 299 TBC-116-126-4011F 2" P Passive - Incorporated 300 TBC116-126-4011G 2" P Passive - Incorporated 301 TBC-116-126-4018 3" C#2B877 Passive - Incorporated 302 TBC-116-126-4019 3" C #2B869 Passive - Incorporated 303 TBC -116-126-4020 4" C #2B870, JB (B-SIDE) Passive Incorporated 304 TBC-116-126-4021 3" C U2B871, JB (B-SIDE) Passive - Incorporated 305 TBC-116-126-4022 2' x 8" BO Passive - Incorporated 306 TBC-116-126-4022A 6" SLV wI CABLES Passive Incorporated 307 TBC*116*126-4022B 6" SLV wI CABLES Passive Incorporated 308 TBC-116*126-4022C 6" SLVwl ALS Passive - Incorporated 309 TBC-116-126*4022D 3/4" C Passive - Incorporated 310 TBC-116-126-4023 1 )1," C U3P158 Passive - Incorporated 311 TBC-116-126-4024 %" CU3P156 Passive - Incorporated 312 TBC-116-126-4025 %" ( Passive - Incorporated 313 TBC-116-126*4026 4" C OE #2B874 Passive - Incorporated 314 TBC-116-126-4027 4" C OE #2B878 Passive - Incorporated 315 TBC-116-126-4028 4" C OE #2 B870 Passive - Incorporated 316 TBC-11~ 126-4029 3" COE Passive - Incorporated 317 TBC-116-126-4030 1 y," C OE #3P016 Passive - Incorporated 318 TBC-116-126-4031 2'x8"BO Passive - Incorporated 319 TBC-116-126-4031A 6" SlV wi CABLES Passive - Incorporated Page 37

NTTF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 Table 13: Inspected Floodinl Features MeetingAcceptante Criteria Features.mmedlately JudCed as ActII!ptable No. Feature 1.0. Number Description PassivelActive Incorporated/Temporary 320 TBC-116-12fY4031B 6" SLV wi CABLES PaSSive -Incorporated 321 TBC-1l6-126-4031C 6" SLV wi CABLES PaSSive -Incorporated 322 TBC -116-126-4032 6" CB w/ALS LINES & CO-X (B-SIDE) PaSSive - Incorporated 323 TBC-116-126-4034 2" CaE w/pG w/o CABLE PaSSive -Incorporated 324 TBC-116-126-4035 2" C OE w/pG wlo CABLE Passive - Incorporated 325 TBC-116-126-4036 2" C OE w/pG w/o CABLE Passive Incorporated 326 TBC-116-126-4037 8" CB w/(4) 1" CU AIR LINES Passive Incorporated 327 TBC-116-126-4038 6" CB w/(4) 1" CU AIR LINES Passive - Incorporated 328 TBC-116-126-4039 3" CB w/CABLES Passive - Incorporated 329 TBC-116-126-West Wall West Wall Passive Incorporated 330 RWC-I08-141-4006 4' x 4' B.O. Passive Incorporated 331 H21 Hatch PaSSive Incorporated 332 H22 Hatch Passive - Incorporated 333 H23 Hatch Passive - Incorporated 334 H24 Hatch Passive - Incorporated 335 RW3-116-156-4001 7" OD SLEEVE PaSSive - Incorporated 336 RW3-116-1S6-4002 7" aD SLEEVE Passive - Incorporated 337 RW3-116-1S6-4003 7" OD SLEEVE Passive -Incorporated 338 RW3-116-156-4004 7" OD SLEEVE Passive - Incorporated 339 RW3-116-156-4005 7" aD SLEEVE Passive - Incorporated 340 RW3-11fY156-4006 7" aD SLEEVE PaSSive - Incorporated 341 RB3-116-157-4002 6" SLV Passive - Incorporated 342 RB3-116-157-West Wall West Wall Passive - Incorporated Page 38

NTTF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 Table #3: Inspected Floodil1lFeatuf.s Meeting A~ptana! Criteria Features!mmediately Judaed as Aeeeptable No. feature I.D. Number Description Passive/Active Incorporated/Temporary 343 RB3-116-158-400l 18" P Passive - Incorporated 344 RB3-116-158-West Wall West Wall Passive - Incorporated 345 RB3*116*159* 2001 3" C.D£. IIZD3L019 Passive* Incorporated 346 RB3*116*lS9*2002 3" CO£. IIZD3L021 Passive - Incorporated 347 RB3-116*l59-2003 3" CO£. IIZD3L023 Passive - Incorporated 348 RB3-116*159-East Wall East Wall Passive* Incorporated 349 RB3-116-159-North Wall North Wall Passive* Incorporated 350 RB3-116-159-West Wall West Wall Passive Incorporated 351 RB3-116-l60-1001 12" SLV w/lO" P Passive Incorporated 352 RB3-116-l60*1002 22" SLY w/20" P Passive Incorporated 3" CB w/AL COATED CABLE & FLEX. Al 353 RB3-116*160-200l Passive - Incorporated COA rED CABLE 354 RB3*116-l60*2002 5" SLY w/2 )1," P Passive Incorporated 4" SLY w/2" P (B-SIDE CUT PIPE 355 RB3*116-160*2003 Passive* Incorporated w/WELDED CAP) 356 RB3*116*160-2004 5" SLVw/3" P Passive* Incorporated 357 RB3-116-160-2009 12" CB Passive - Incorporated 358 RB3-116-160-2009A 2" P Passive - Incorporated 359 RB3-116-160-2013 1)1," C w/o CABLE, SPARE Passive - Incorporated 360 RB3-116-160-2014 1 y," C w/o CABLE, SPARE Passive Incorporated 361 RB3-116-160-2015 1 H CB. Passive - Incorporated 362 RB3-116-160-East Wall East Wall Passive - Incorporated 363 RB3-116-160-North Wall North Wall Passive - Incorporated 364 RB3-116-161-2001 3/8" CB (DOOR FRAME) Passive - Incorporated 365 RB3-116-161-2002 6" CB w/(2) y," ALS & (3) ~" ALS Passive - Incorporated Page 39

NTIF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 Table '3: In$pe(;ted Flooding Features Meeting Acceptance Criteria Features Imnredlately Judged as Acceptable No. Feature 1.0. Number Description PassivelActive Incorporated/Temporary 366 RBHlt).161*2003 yC PaSSive Incorporated 367 RBHI6*161*2004 1 Yo" CB Passive Incorporated 368 RB3*116*161* 2005 1 Yo" CB Passive Incorporated 369 RB3*116*161*2006 2" CB Passive Incorporated 370 RB3*116*161*2007 1" C PaSSive Incorporated 371 R83-116-161*2008 3")( 6" BO w/CABLE (CUT-OFF) Passive - Incorporated 372 RB3*11t).161-2009 %"( PaSSive -Incorporated 373 RB3*116-161-2010 2" CB. w/CONDUIT Passive Incorporated 374 RB3-116-161-2011 2" CB PaSSive Incorporated 375 RB3-116-161-East Wall East Wall Passive Incorporated 376 H2O Hatch Passive Incorporated I 377 RW3-116-162-2001 4" SLY w/2" CU P Passive - Incorporated 378 RW3*116-162-2002 4" SLY w/2" CU P Passive . Incorporated 379 RW3-116-162-2003 6" SLY w/3" P Passive Incorporated 380 RW3-116-162-2004 1" C 113P530 Passive Incorporated 381 RW3-116-162 -2005 1" C 113P529 PaSSive Incorporated 382 RW3-116-162-2006 2" CII3M697 Passive* Incorporated 383 RW3-116-162-2007 2" C1I3M720 Passive* Incorporated 384 RW3-116-162-2008 2" CII3M710 Passive* Incorporated 385 RW3-116-162-2009 2" CII3M70S Passive* Incorporated 386 RW3-116-162*2010 4" SLY w/(8) ALS & (1) 1" FLEX ALS Passive* Incorporated 387 RW3-116-162-2011 4" SLY w/3" CU P Passive* Incorporated 388 RW3-116-162-2012 8" SLVw/ALS Passive* Incorporated Page 40

NTIF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 Table 113: Inspeded Flooding Features Meeting JW:eptance Criteria Featureslmmedlatl!ly JudJed as Acceptable No. Feature 1.0. Number Description Passive/Active Incorporated/Temporarv 389 RW3-116-162-2013 4" SlV w/3" CU P Passive Incorporated 6" C w/CA8lE #38226, #3L1010, l8-390 RW3-116-162-2014 Passive - Incorporated 1437 391 RW3-116-162-2015 6" C #38225, #3L063, JB-l437 Passive - Incorporated 392 RW3-116-162-2016 6" C #38229, #3L062, JB-J436 Passive - Incorporated 6" C w/CA8LE #38228, #3LI011, JB-393 RW3-116-162-2017 Passive Incorporated J436 394 RW3-116-162-2018 4" SlV w/ 1 W' INS, p, Passive - Incorporated 39S RW3-116-162-2019 4" CB Passive Incorporated 396 RW3-116-162-2020 2" C OE w/o PG w/CA8lE Passive Incorporated 397 RW3-116-162-2021 2" C OE w/CABLE Passive - Incorporated 398 RW3-116-162-2022 2" C OE w/PG w/o CABLE Passive - Incorporated 399 RW3-116-162-2023 2" C OE w/PG wlo CABLE Passive - Incorporated 400 RW3-116-162-2024 2" CB Passive - Incorporated 401 RW3-116-162-2025 1 y," CB, y," TUBING (1 TUBE) Passive Incorporated 402 RW3-116-162-2026 3" CB w/ 1" S5, P Passive - Incorporated I 403 RW3-116-162-2028 6" SLEEVE Passive Incorporated 404 RW3-116-162-4001 18" CB w/12" INSUL P (E5W RETURN) Passive Incorporated 405 RW3-116-162-4002 12" INSUL P ESW "A" PMP DISCHG Passive Incorporated 406 RW3-116-162-East Wall East Wall Passive Incorporated 407 RW3-116-162-West Wall West Wall Passive Incorporated 408 RW3-116-162-2027 SEISMIC GAP Passive - Incorporated 409 RB2-135-2-Floor Exterior Unit 2 West Side @ 135' Passive - Incorporated 410 RB3-135-3-Floor Exterior Unit 3 West Side @ 135' Passive - Incorporated 411 RB2-116-ST18-2001 1" C (BLUE LIGHT) Passive -Incorporated Page 41

NTIF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 Table 1$: Inspected Flooding Features Meetifll Atceptance Criteria FeatllfeSlmrnediateiy Judged as Acceptable No. Feature 1.0. Number DKcriptlon Passive/Active Incorporated/Temporary 412 RB2-116-ST1S-East Wall East Wall Passive Incorporated 413 RB2-11~ST18-South Wall South Wall Passive -Incorporated 414 RB2-116-EL19-East Wall East Wall Passive Incorporated 415 RB2-116-ST19-East Wall East Wall Passive - Incorporated 416 RB3-116-ST22-East Wall East Wall Passive Incorporated 417 RB3-116-EL22-East Wall East Wall Passive Incorporated 418 RB3-116-ST22-2001 3" WALL RECEPTACLE Passive Incorporated 419 RBH16-ST22-Z002 3" EMDI LIGHT RECEPTACLE Passive - Incorporated 420 RB3-116-ST23-2001 %"C Passive - Incorporated 421 RB3-116-ST23-East Wall East Wall Passive Incorporated 422 RB3-116-ST23-North Waif North Wall Passive Incorporated 112' Emergency Pump Structure. Passive Features 423 CWZ-112-S01-2001 2)1," CB Passive - Incorporated 424 CW2-112-801-Z002 2 y," CB Passive Incorporated 425 CW2-112-S01-2003 5" x W' C REDUCER Passive - Incorporated 426 CW2-112-801-Z004 1" C Passive - Incorporated 427 CW2-112-801-200S 1" C Passive Incorporated 428 CW2-112-S01-2006 1"C Passive Incorporated 429 CW2-112-80i-2007 l"C Passive - Incorporated 430 CW2-112-801-200S 3" x4" B.O. Passive Incorporated Page 42

NTTF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 Table 13: Inspeded FIoacIlnt feltufts MMtq ~","ce Criteria Futures l~eIy Jud&ed as ~bIe No. Feature 1.0. Number Description Passive/Active Incorporated{Temporary 431 CW2-112-801-Z009 1" C #ZB2G062 Passive - Incorporated 432 CW2-112-801-2010 1" C #ZB2C259 Passive - Incorporated 433 CW2-112-801 -2011 1" C #2G061 Passive - Incorporated 434 CW2-112 -801-2012 1" C #2G059 Passive - Incorporated 435 CW2-112 -801-2013 2" C #ZB2C060 Passive -Incorporated 436 CW2-112-801-2014 2~" C#2G214 Passive - Incorporated 437 CW2-112-801-5001 NOT IN PIMS Passive - Incorporated 438 CW2-112-801-S002 2" C #2B2 C060 Pa ssive - Incorporated 439 CW2-112-801-5003 1" C#2GOS9 Passive - Incorporated 440 CW2-1l2-801-5004 1" C#ZG061 Passive - Incorporated 441 CWZ-llZ-801-500S 1 X" C #ZB2GZS9 Passive - Incorporated 442 CW2-llZ-801 -S006 LEVEL INDICATOR Passive - Incorporated 443 CW2-112-801-S007 1" C #ZB2G062 Passive - Incorporated 444 CWZ-llZ-801-S008 8" SLVw/4" P Passive - Incorporated 445 CWZ-llZ-801-5009 1" C Passive -Incorporated 446 CW2-1l2-801-S010 1" C Passive - Incorporated Page 43

NTIF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 Table 13: In~ floodlnl features Meetlnl AUeptance Criteria featUres Immediately Judpd as Acceptable No. Feature 1.0. Number Description Passive/Active Incorporated/Temporary 447 CW2, llHJ01 ,5011 1" C Passive - Incorporated 448 CW2-112-801-5012 3" C Passive - Incorporated 449 CW2-112-801-5013 %" C Passive - Incorporated 450 CW2-11Z-801-5014 %11 C Passive Incorporated 451 CW2-11Z-801-5015 5" C Passive Incorporated 452 CW2-112-801-5016 1" C#2G456 Passive - Incorporated 453 CW2-112-801-S017 1" C Passive Incorporated 454 CW2-112-801-5018 1" C Passive Incorporated 24" SLV w/lO" P ESW "A" PMP 455 CW2-112-801-5019 Passive - Incorporated DISCHG 456 CWZ-112-801-5020 1" C PLUGGED Passive - Incorporated 457 CWZ-112-801-5020A 1" CPLUGGED Passive Incorporated 458 CW2-112-801-5021A 2" C PLUGGED Passive -Incorporated 459 CW2-112-801-5021 2" C PLUGGED Passive - Incorporated 460 CW2-1l2-801-5022 2" ( Passive -Incorporated 461 CW2 -112-801-5023 2"( Passive -Incorporated 462 CW2-1l2-801-5024 %"C Passive -Incorporated Page 44

NTTF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 Table t#~: InspectEd Floodin, features MCletll'11 Aa:eptanC8 Criteria features Immediately Judged as Aa:eptable No. Feature 1.0. Number Description PassivelActive Incorporateci/Temporary 463 CW2-112-801-5025 8" 5LVw/3" P Passive Incorporated 464 CW2-112*801*5026 16" SLV w/12" P Passive* Incorporated 465 CW2*112*801*5027 8" SLVw/6" P Passive* Incorporated 466 (W2-112*801*5028 12" SLV w/lO" P Passive Incorporated 467 CWZ-112-801-5029 1)1," C#ZB2G213 Passive Incorporated 468 CW2*112-801*S030 1" C Passive - Incorporated 469 CW2-l12*801*5031 1" C Passive* Incorporated 470 CW2*112*801*5032 1" C Passive* Incorporated 471 CW2*112*S01*S033 1"C Passive Incorporated 472 CWZ*112-S01-S034 1" C Passive* Incorporated 473 CW2-112*S01-S035 2" C Passive Incorporated 474 CW2-112-S01*S036 1" C Passive* Incorporated 475 CW2-112-801-5037 W'C Passive* Incorporated 476 CW2*112*801-S038 1" C Passive* Incorporated 477 CW2-112-S01*S039 1" C Passive - Incorporated 478 CWZ-llZ-801-5040 1 It, C #ZA2G236 Passive - Incorporated Page 45

NTIF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 Table #3: Inspec:ted Floodin& Features Meeting Acceptance Criteria features Immediately Judged as Acceptable No, Feature I.D. Number Description PassivelActive Incorporated/lemporary 479 CW2~112~801-S041 1 Yi" C IIZB2G234 Passive ~ Incorporated 24" SLV w/18" P HPCI TO RHR "A" &

480 CWH12-801-S042 lIe li Passive Incorporated 481 CW2-112-801-S043 1" C Passive - Incorporated 482 CWZ-112-801-S044 1 y," C Passive Incorporated 483 CW2-112-801-S045 1" CIIZG1S2 Passive - Incorporated 484 CW2-112 -801-S046 1" C Passive - Incorporated 485 CW2-112-801-S047 3" SLY w/1" DRN P Passive - Incorporated 486 CW2-112-801-S048 1" CIIZG452 Passive Incorporated 487 CWZ-llZ-801-S049 1" CIIZG467 Passive - Incorporated 488 CW2-112-801-50S0 2" C Passive Incorporated 489 CW2-112-801-S0S1 6" C Passive Incorporated C 112A480 IN 12" x 32" x 3" METAL 490 CW2-112-801-50S2 Passive - Incorporated FRAME 491 CW2-112-801-S0S4 2 )1," C 112B2G278 Passive -Incorporated 492 CW2-1l2-801-S0SS 1 y," CII2A688 Passive - Incorporated 493 CW2-1l2-801-S0S6 %/C Passive - Incorporated 494 CW2-1l2-801-S0S7 2 Yi" C 112G301 Passive Incorporated Page 46

NTIF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 T." 'J: Inspected FIoodinI tI.nS .. ~Ct Fatura ImrnedIItety Judplas ~

No. Feature 1.0. Number DescriptIon Passive/Active Incorporatecl/Ternporary 495 CVV2-112~1-50S8 6" C Passive - locorporated 496 CVV2-112-801-5059 1" C IIZG2A631 Passive - Incorporated 497 CVV2-112-801-SOGO 1" C Passive - Incorporated 498 CVV2 -112-801-5OG1 1" C Passive - Incorporated 499 CVV2-112-801-S062 3" CB w/3/4" P Passive - Incorporated 500 CVV2-112-801-5OG3 1" (IIZG152 Passive - Incorporated 501 CVV2-112-801-5OG4 1 W C#2AG610 Passive - Incorporated 502 CVV2-112-801-5OG5 W' (#ZB2G279 Passive - Incorporated 503 CVV2 -112 -801-5066 4" FLR DRN Passive - Incorporated 504 CVV2-1l2-801-5067 1" (#2A167 Passive - Incorporated 505 CVV2-1l2-801-5068 24" SLY w/18" P Passive - Incorporated 506 CVV2-1l2-801-5069 1 W (1I2A612 Passive - Incorporated 507 CVV2-112-801-5070 %" (1I2G659 Passive - Incorporated 508 CVV2-112-801-5071 1" (1I2G456 Passive - Incorporated 509 CVV2-112-801-50n 1n (#2G466 Passive -Incorporated 510 CVV2-112-801-5073 1W( Passive - Incorporated Page 47

NTTF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 Table #3: Inspeded FIoodIRg features MeetiRg A<<:eptance Criteria Features Immediately ludSed all Ael:eptable No. Feature 1.0. Number Description PassivelActive Incorporated/Temporary 511 CW2*112*801*5074 3" CB w/3/4" DRN P Passive Incorporated S12 CW2*112*801*S075 %11 C Passive Incorporated 513 CW2*112*801*5076 :y.U( Passive Incorporated 514 CW2*112*801*5077 4" C Passive Incorporated 515 CW2*112*801*5078 6" C Passive* Incorporated 516 CW2*11Z*801*5079 2" CItZGZ72 Passive Incorporated 517 CW2*112 *801*5080 1 W' C ItZB2G276 Passive* Incorporated 518 CW2*112*801*5081 %/C Passive . Incorporated 519 CW2*112*801*5082 1" C Passive . Incorporated 520 CW2*112*801*5083 4" C PLUGGED Passive . Incorporated 521 CW2*112*801*5083A 4" C PLUGGED Passive Incorporated 522 CW2*112*801*5084 4" C PLUGGED Passive* Incorporated 523 CW2*112-801-5084A 4" C PLUGGED Passive - Incorporated 524 CW2-112-801-5085 4" C PLUGGED Passive Incorporated 525 CW2*112-801*5085A 4" C PLUGGED Passive* Incorporated 526 CW2-1l2*801-5086 4"C PLUGGED Passive* Incorporated Page 48

NTIF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5,2012 Table '3: Inspeaed Flooding Features Meeting Acceptance Criteria Features Immediately Judged as Acceptable No. Feature 1.0. Number Description PassivelActive Incorporated/Temporary 527 CW2-112-801-5086A 4" C PLUGGED Passive - Incorporated 528 CWZ-112-801-5087 6"( Passive - Incorporated 529 CW2-112-801-5088 1 y," C #ZD2A619 Passive Incorporated 530 CW2-112-801-5089 1" C #2G466 Passive - Incorporated 531 CVVl-112-801-5090 2 v," C #2G214 Passive - Incorporated 532 CVV2-112-801-5091 1" C#2G659 Passive Incorporated 533 CW2-112-801-509Z 1" C Passive Incorporated C #ZC2484IN 12" x 32" X 3" METAL 534 CWl-112-801-5093 Passive - Incorporated FRAME 535 CW2-112-801-5093A C #ZC2484 Passive - Incorporated C #ZA2A635 IN 12" x 32" X 3" METAL 536 CW2-112-801-5094 Passive - Incorporated FRAME 537 CW2-112-801-5094A C#ZA2A635 Passive - Incorporated 538 CW2-112-801-East Wall East Wall Passive - Incorporated 539 CW2-112-801-South Wall South Wall Passive - Incorporated 540 CW2-112-801-West Wall West Wall Passive - Incorporated 541 CVV3-112-143-1001 3" CB Passive - Incorporated 542 CW3-1l2-143-1002 3"CB Passive - Incorporated Page 49

NTIF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 1lJble #1: l~d Floodins Futures Meetins A<<eptanM Criteria features Jmmediately Judged as Acceptable No. feature 1.0. Number Description PassivelActive Incorporated/Temporary 543 CW3-112-143-1003 3"CB Passive - Incorporated 544 CW2-112-802-Z001 4)1," PLUG Passive -Incorporated 545 CW2-112-80Z*2002 4)1," PLUG Passive* Incorporated 546 CW2-112*802*2003 1" C Passive - Incorporated 547 CW2-112*802*2004 1" C Passive Incorporated 548 CW2-112-802-2005 1" C Passive Incorporated 549 CW2-112*802*2006 1" C Passive Incorporated 550 CW2-112-802*2007 1" C Passive* Incorporated 551 CW2*112-145*300S 4" SLY Passive Incorporated 552 CW2-112-145*3006 4"SLV Passive* Incorporated 553 CW2*112-145*3007 14" C B w/12" P Passive Incorporated 554 CW2-112-145-3008 1" C #2G81O (EY5 FTG.) Passive Incorporated 555 CW2-112-145-3009 12" CB w/l0" INS P Passive Incorporated 556 CW2-112-145-3010 1 X" C #2G667 (EYS FTG.) Passive* Incorporated 557 CW2-112-145-3011 10" SLY w/(2) 2" PIPES Passive Incorporated 558 CW2-112-145*3011A 3/4" CONDUIT Passive* Incorporated Page 50

NTTF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5,2012 Table '9: Inspeded Flooding Features Meeting Ac:tfilplance Criteria Features Immediately Judged as Ac:tfilptable No. Feature 1.0. Number Description PassivelActive Incorporatoo/Temporary 559 CWZ-llZ-145-3012 5" CSw/3" P Passive Incorporated 560 CW2-11Z-145-3013 3" CB w/1 W' CU P Passive -Incorporated 561 CW2-112-145-3014 3" CB w/1 W' CU P Passive - Incorporated 562 CWZ-I1Z-145-3015 3" CB Passive - Incorporated 563 CW2-112-145-3016 3" CB Passive - Incorporated 564 CW2-112-145-3017 3" CB Passive Incorporated 565 CWZ-112-802-5001 4"5lVw/2"CUP Passive - Incorporated 566 CWZ-I1Z-802-5002 4" SLY w/2 " CU P Passive - Incorporated 567 CWZ-112-802-5003 5" CB w/4" P Passive - Incorporated 568 CW2-11Z-80Z-5004 1" C #ZB2G212 Passive - Incorporated 569 CW2-112-80Z-5005 5" CB w/4" P Passive - Incorporated 570 CW2-112-802-S006 5" CB w/4" P Passive Incorporated 571 CW2-11Z-802-5007 1" C Passive - Incorporated 572 CWZ-llZ-802-5008 10" SLY w/6" P Passive Incorporated 573 CW2-112-802-5009 5" SLVw/2" P Passive -Incorporated 574 CW2-11Z-80Z-5010 2" C #ZB2G260 Passive - Incorporated Page 51

NTTF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 Table '3: Insptlded FIoodIrll Fealun;s Meeting A<<eptance Criteria Features Itnmediately Judged as A<<eptable No. Feature I.D. Number Description PassivelActive Incorporated/Temporary 575 CW2-112-802-S012 1"C Passive - Incorporated 576 CW2-112-802-S013 1" C 112B2G212 Passive Incorporated 577 CW2-112*802-S014 3" C IIZB2G178 Passive - Incorporated 578 CW2-112*802*5015 2"P Passive* Incorporated 579 CW2-112-802-S016 FLOOR DRAIN PIPE Passive - Incorporated 580 CW2-112-802-East Wall East Wall Passive* Incorporated 581 CW2-112-145-South Wall South Wall Passive - Incorporated 582 CW2-112-802-Slab Slab Passive* Incorporated 583 CW3-112-803-2001 1" C 113G233 Passive Incorporated 584 CW3-112-803-2002 2" C #ZA3G841 Passive - Incorporated 585 CW3-112-803-2003 2" CII2G961 Passive - Incorporated 586 CW3-112-803-2004 2" C #203G005 Passive* Incorporated 587 CW3-112-803-2005 2" CIIZG960 Passive - Incorporated 588 CW3-112-803-2006 2" C IIZB3G003 Passive - Incorporated 589 CW3-112-803-2007 2" C IIZC3G003 Passive Incorporated 590 CW3-112-803-2008 2" C#26792 Passive - Incorporated Page 52

NTTF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5,2012 Table #3: jnspeeted flooding features Meeting AlXf!9tance Criteria f'eatureslmmediatelv judged a5 Acceptable No. Feature 1.0. Number Description PassivelActive Incorporated/Temporary 591 CW3-112-803-2009 1" C#3G059 Passive Incorporated 592 CW3-112-803-2010 8" SLV w/4" PROOF ORN Passive Incorporated 593 CW3*112-803-2011 4 v," COL w/PLUG Passive - Incorporated 594 CW3-112-803-2012 4 v," CO.E. w/PLUG Passive Incorporated 595 CW3-112 -803-2013 4 v," CO.E. w/PLUG Passive Incorporated 596 CW3-112*803*2014 4 v," e.O.E. w/PLUG Passive* Incorporated 597 CW3-112-803-2015 4 X" x %" C. REDUCER Passive - Incorporated 598 CW3-112-803-2016 1 );," C #3G297 Passive Incorporated 599 CW3-112*803-2017 1" C #3G061 Passive Incorporated 600 CW3-112-803-2018 1 );," C #3A620 Passive* Incorporated 601 CW3-112-803-2019 1 Yz" C #ZA3G259 Passive Incorporated 602 CW3*112-803-2020 2" C #ZA2GOS8 Passive - Incorporated 603 CW3-112-803-2021 1" CSPARE Passive - Incorporated 604 CW3-112-803-2022 2" C#2G441 Passive - Incorporated 605 CW3-112-803-2023 1Yz"C Passive - Incorporated 606 CW3-112 -803-2024 1"C Passive* Incorporated Page 53

NTIF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012

.- -~------- . -- .*..

Table '3: Inspected AoocfIna "-tUffl Me AccepGnctO Futures Imrne4JIte+y JudIe pta" No. Feature 1.0. Number Description Passive/ActIve Incorporated/Temporary 607 CW3-112-803-2025 1" CSPARE Passive - Incorporated 608 CW3-112-803-East Wall East Wall Passive - Incorporated 609 CW3-112-803-S001 5" C ItZA3A487 Pa ssive - Incorporated 610 CW3-112-803-5002 5" C ItZD3A476 Pa ssive - Incorporated 611 CW3-112-803-5003 6" P w/PLUG Pa ssive - Incorporated 612 CW3-112-803-5004 6" P w/PLUG Pa ssive - Incorporated 613 CW3-112-803-5005 Z" DRN CAPPED Passive - Incorporated 614 CW3 -112-803-5006 1 X" C #3A623 Pa ssive - Incorporated 615 CW3-112-803-5007 %" C Passive - Incorporated 616 CW3-112-803-S008 %"C Passive - Incorporated 617 CW3-112-803-5009 1 )1," C ItZB2G297 Passive - Incorporated 618 CW3-112-803-5010 3" C 1t2G537 Passive - Incorporated 619 CW3-112-803-5011 %" ( Pa ssive - Incorporated 620 CW3-112-803-5012 %" C Passive - Incorporated 621 CW3-112-803-5013 2" DRN CAPPED Passive - Incorporated 622 CW3-112-803-5014 4" SLY w/3" C #3A492 Passive - Incorporated Page 54

NTTF Recommendation 2.3 (Walkdowns): Flooding helon Corporation November 5, 2012 Table #3: In~ed FIoodIn,g Features fIIleetIn,gAC(eptana! criteria Features Immediately Judged as AC(eptable No. Feature 1.0. Number Description PassivelActive Incorporated/Temporary 623 CW3*112*803*5015 1 y," C #ZA3A663 Passive* Incorporated 624 eW3*112*803*5016 1 y," C 113A017 Passive Incorporated 625 CW3*112*803*5017 1 y," e #ZC3A634 Passive Incorporated 626 CW3*112*803*5018 1 y," C 113A638 Passive* Incorporated 627 CW3*112*803*5019 1 y," ell3A637 Passive Incorporated 628 CWH12*803*S020 NOT IN PIMS Passive Incorporated 629 CW3*112*803*5021 Iy," CII3A668 Passive Incorporated 630 CW3*112 *803*5022 1 y," C Passive Incorporated 631 CWH12*803*S023 3" C #2G301 Passive Incorporated 632 CW3*112*803*5024 3" C IIZA3GOOl Passive* Incorporated 633 CW3*112*803*5025 1"C Passive* Incorporated 634 CW3*112*803*5026 1"C Passive Incorporated 635 CW3*112*803*5027 %"C Passive* Incorporated 636 eW3*112*803*5028 2" C #3G272 Passive Incorporated 637 CW3*112*803*5029 2" e #ZA2G291 Passive* Incorporated eIRe WATER STRUCTURE PEN SEAL!"

638 CW3*112*803*5030 Passive* Incorporated C

Page 55

NTIF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 Table '3: 'l'Ispeded Flooding Feature$ Meeting Atcepmnt;e Criteria Features Immediately Judged as Atceptable No. Feature J.D. Number Description PassivelActive Incorporated/Temporary 639 CW3*112*803*5031 2" C Passive Incorporated 640 CW3*112*803*5032 1" C Passive* Incorporated 641 CW3*112*803*5033 1" C Passive* Incorporated 642 CW3*112*803*5034 1" C#2G962 Passive Incorporated 643 CW3*112*803*5035 1" C Passive* Incorporated 644 CW3*112*803*5036 1" C Passive Incorporated 645 CW3*112*803*5037 1" C Passive Incorporated 646 CW3*112*803*5037A 5" CO,E. w/PLUG Passive Incorporated 647 CW3*112*803*5038 6"C Passive Incorporated 648 CW3*112*803*5039 11/2" C Passive . Incorporated 649 CW3*112*803*5040 %"C Passive* Incorporated 650 CW3*112*803*5041 %"C Passive* Incorporated 651 CW3*112*803*5042 2" DRN CAPPED Passive . Incorporated 652 CW3*112*803*5043 6" C Passive* Incorporated 653 CW3*112*803*5044 11/2" C Passive . Incorporated 654 CW3*112*803*5045 %IJC Passive* Incorporated Page 56

NTTF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 Table #J: Inspeded FIoodi. Features Meeti. ~ptance Criteria features Immediately JlIdpd as Aeceptable No. Feature 1.0. Number Description Passive/Active Incorporated/Temporary 655 ON3-112-B03-5046 ~JJC Passive Incorporated 656 CW3-112-803-5047 2" DRN CAPPED Passive - Incorporated 657 CW3-112 -S03-S04S 1 )1," C Passive Incorporated 658 CW3-112-S03-S049 1" Cw/PLUG Passive Incorporated 659 CW3-112-S03-50S0 6" Pw/PlUG Passive Incorporated 660 CW3-112-803-S0S1 %" e.O.E. w/PLUG Passive - Incorporated 661 CW3-112-S03-S0S2 4" C #ZB2A460 Passive Incorporated 662 CW3-112-803*5053 4" C #ZB2AS09 Passive Incorporated 663 CW3-112 *803-5054 1}s" C Passive - Incorporated 664 CW3-112-S03-5055 1" C Passive - Incorporated 665 CW3-112-803-5056 ly,"C Passive - Incorporated 666 CW3-112*S03*5057 5" e.O.E. w/PLUG Passive Incorporated 667 CW3-112*S03-5057A 5" e.O.E. w/PLUG Passive - Incorporated 66S CW3*112-S03-5058 5" e.O.E. w/PLUG Passive - Incorporated 669 CW3-1l2 -803-5058A 5" e.0.E. w/PLUG Passive - Incorporated 670 CW3-112-803-50S9 5" e.O.E. w/PLUG Passive Incorporated Page 57

NTTF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 Table#a~ In~ PIood.usFeatures Meeting~ptanceCriterla Features Immediately JudSed as Acceptable No. Feature I.D. Number Description Passive/Active Incorporated/Temporary 671 CW3~112~803~5059A 5" e.O.£. w/PLUG Passive Incorporated 672 CW3~112-803~5060 5" e.O.E. w/PLUG Passive Incorporated 673 CW3-112 ~803-5060A 5" e.O.E. w/PlUG Passive Incorporated 674 CW3-112~803*5061 1 y,' C Passive - Incorporated 675 CW3*112 -803-5062 ly,'C Passive Incorporated 24" SLV w/20" P ESW PMP "B" 676 CW3*112-803-5063 Passive - Incorporated DISCHG 14" SlVw/12" P MOTOR FIRE PMP 677 CW3*112-803-5064 Passive - Incorporated DISCHG 678 CW3*112-803-5065 3'-8 W' DIA MAN HOLE Passive Incorporated 679 CW3-112-803-5066 1" C #2G293 Passive - Incorporated 680 CW3-112-803-5067 1" C #2G292 Passive Incorporated 681 CW3-112-803-5068 1" C Passive - Incorporated 682 CW3-112-803-5069 1" C Passive Incorporated 4" CB FOR LC(5SLAB NOT 683 CW3-112-803-5070 Passive - Incorporated PENETRATED) 684 CW3-112-803-5071 1 W' C ltZB3G060 Passive Incorporated 685 CW3-11Z-803-S072 8" SlV w/4" P (PMP BAY VENT) Passive - Incorporated Page 58

NTTF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 Table #3; Inspected floodln, felJtures Meetil1l Acceptance Criteria FeatUfeSlmmedlately Jl.ldBfild as Acceptable No. Feature 1.0. Number Description PassivelActive Incorporated/Temporary 686 CW3-112-803-5073 2"C Passive Incorporated 687 CW3-112-803-5074 1" C Passive Incorporated 688 CW3-112-803-507S 2" C Passive

Incorporated 689 CW3-112-803-5076 1 }>" C #ZAZGOS8 Passive Incorporated 690 CW3-112 -803-5077 1}>,' C #3A620 Passive Incorporated 691 CW3-112-803-S078 1" C#3G061 Passive Incorporated 692 CW3-112-803-S079 1 y," C#3G297 Passive - Incorporated 693 CW3-112-803-S080 7' -6" W x 3' -10" D SUMP PIT COVER Passive - Incorporated 694 CW3-112-803-5081 W' P w/SOCET & PLUG Passive Incorporated 695 CW3-112 -803-5082 6" CB w/4" P (LS-3447 ESW PMP RM) Passive* Incorporated 6" CB w/4" P (LT-3804A HPSW WATER 696 CW3-112-803-5083 Passive - Incorporated LEVEL) 6" CB w/4" P (LT-3804B HPSW WATER 697 CW3-112-803-5084 Passive Incorporated LEVEl) 698 CW3-112 -803-5085 8" SLVw/6" P Passive Incorporated 12" SL V w/l(J' P MOTOR FIRE PMP 699 CW3-112-803*5086 Passive Incorporated DISCHG Page 59

NTTF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 Tabll! #1: Inspected FIoodIn& Features Meetina A<:teptanm CrIteria Features Immediately JuiJled as A<:teptable No. Feature 1.0. Number Description PassivelActive Incorporated/Temporary 700 CW3~ 112~803~5087 %"( Passive Incorporated 701 CW3*112~803*5088 1W'C Passive Incorporated 702 CW3*112*803*S0S9 4" HR DRN w/l2" GRILL Passive - Incorporated 703 CWH 12-803*5090 3'*8 )4" DIA MAN HOlE Passive Incorporated 704 CW3*112 *803~5091 y." P w/SOCKET & PLUG Passive - Incorporated 705 CW3*112-803*5092 1" C#3G059 Passive* Incorporated 706 CW3*112*803*5093 10" SLVw/6" P Passive* Incorporated 707 CW3*112-S03*5094 5" 5LV w/1 y," P Passive Incorporated 70S CW3*112 *803*5095 W' C#3G233 Passive* Incorporated 709 CW3*112*S03*5096 2" P w/SOCKET & PLUG Passive Incorporated 710 CW3*112*S03~S097 1" P w/SOCKET & PLUG Passive - Incorporated 711 CW3-112-S03-S098 8" SLVw/6" P Passive Incorporated 712 CW3-l12*S03*S099 1" C #AZ3G212 Passive - Incorporated 713 CW3-112*S03-S100 11/2" C Passive - Incorporated 714 CW3-112-S03-5100A 11/2" C Passive - Incorporated 715 CW3-112-S03-5101 1" C Passive* Incorporated Page 60

NTIF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 T.bIe U : IMf*t.ed Aaad" Fulures Meet. . ~ criteria I Fatur"I~ Jucfpd .. ~Ie No. Feature 1.0. Number Description Passive/Active Incorporated/Temporary 716 CW3*112-803*510lA 1" C Passive* Incorporated 22" SlV w/1S" P HPSW TO RHR HX 717 CW3*112 -803*5102 Passive - Incorporated UA" & fIr:

718 CVV3*112~03-5103 11/2" C Passive* Incorporated 719 CW3-112-S03-S103A 11/2" C Passive* Incorporated 720 CW3-112-803-5104 1" C #3G152 Passive - Incorporated 721 CW3-112-803-S10S 1 Yz" C #ZB3A610 Passive* Incorporated 722 CVV3-112 *S03-5106 1 }S" C #ZA3G291 Passive -Incorporated 723 CW3-112-S03-5107 22" SlV w/1S>> P HPSW TO RHR B & 0 Passive* Incorporated 724 CW3-112-803-5108 lX"C Passive* Incorporated 725 CW3-112-803-5109 1 y," C Passive - Incorporated 726 CVV3-1l2-803-5110 1" C Passive - Incorporated 727 CWH 12-803-5 111 1"C Passive - Incorporated 728 CVV3-112-803-Slab Slab Passive* Incorporated 729 CVV2-112-144-3001 4" SlV wlY INS. P Passive - Incorporated Page 61

NTTF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 Table #3: 'lIlIpetted FIoodI", Features Meetl", Acceptan(e Criteria Featul'U Immediately Judged as Acceptable No. Feature 1.0. Number Description Passive!Active Incorporated/Temporary 730 CWH12-144-3002 3"CB Passive - Incorporated 731 CW2-112-144-3003 3" CB Passive - Incorporated 732 CW2-112-144-3004 3" CB Passive Incorporated 733 CW2-112-144-3005 4" CB Passive - Incorporated 734 CW2-112-144-3006 4" CB Passive Incorporated 735 CW2-112-144-3007 4" CB Passive - Incorporated 736 CW2-112-144-3008 4" SlV Passive Incorporated 737 CWH12-144-3009 2" C Passive Incorporated 738 CW2-112-144-3010 8" SlV w/4" INS. P Passive -Incorporated 739 CW2-112-144-3011 2" C#ZA1377 Passive Incorporated 740 CW2-112-144-3012 2" C (EYS FIG.) Passive Incorporated 741 CW2-112-144-3013 1 y," C #ZG261 (EYS FIG.) Passive -Incorporated 742 CW2-112-144-3014 1 y," C (EYS FTG.) Passive Incorporated 743 CW2-112-144-3015 1 v," C #2G263 (EYS FTG.) Passive - Incorporated 744 CW2-112-144-3016 6"C8 Passive Incorporated 745 CW2-112-144-3017 3"C8 Passive - Incorporated Page 62

NTIF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 Table '3: Inspected Flooding F.eaturesl\lleetiDl Acceptance Criteria ftlatllrAS Immediately Judged as Acceptable No. Feature I.D. Number Description Passive!Active Incorporated/Temporary 746 CWH12*144*3018 3"CB Passive Incorporated 747 CWHIH44*3019 3"CB Passive Incorporated 748 CW2*112*144*3020 2" CB Passive . Incorporated 749 CW2*112*144*3021 2" CB w/l" P Passive Incorporated 750 CW2*112*144*3022 4" CB w/2" P Passive

Incorporated 751 CW2*112*144*3023A 2"CB Passive* Incorporated 752 CW2*112*144*3024 X" C (DOOR JAMB) Passive* Incorporated 753 CW2*11H44*3025 %" C (DOOR JAMB) Passive Incorporated 754 CWH12*144*3026 2" CB Passive Incorporated 755 CW2*l12*144*3027 2" x 4" EMB. ELECTRICAL RECEPTACLE Passive* Incorporated 756 CW2*112*144*3028 1" CB wjCO*X CABLE Passive* Incorporated 757 CWH12*144*3029 1" CB wjCO*X CABLE Passive* Incorporated 758 CWHl2-144*4001 4" EMB RECEPTACLE Passive Incorporated 759 CW2*112*144*4002 3"CB Passive* Incorporated Create CRL per IR 1401537 &

760 CWH12*144*4003 Passive* Incorporated fCR 02*00429 (4" Plug)

Create CRL per IR 1401537 &

761 CW2-112-144*4004 Passive* Incorporated fCR 02*00429 (4" Plug)

Page 63

NTIF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 Table 113: Inspected Flooding Features Meeting Acceptance Criteria Features lrnmedfately Judged as Acceptable No. Feature 1.0. Number Description Passive/Active Incorporated/Temporary Create CRl per IR 1401537 &

762 CW2*112*144*4005 Passive Incorporated EeR 02*00429 (4" Plug)

Create CRL per IR 1401537 &

763 CW2*112*144*4006 Passive Incorporated ECR 02*00429 (4" Plug) 764 CW2*112*144*4007 2" P Passive

Incorporated 765 CW2*112*144*4008 X"C Passive

Incorporated 766 CW2*112*144*4009 Y,II C Passive* Incorporated 767 CW2*112*801*5Iab Slab Passive Incorporated 768 CW2*112*144*North Wall North Wall Passive Incorporated 769 CW2*112*144*$outh Wall South Wall Passive Incorporated 770 CW2*112*144*West Wall West Wall Passive* Incorporated 771 CW2*112*145*3001 10" SlV w/(2) 1" PILOT HOLES Passive* Incorporated 772 CWH 12 *145* 3003 4" CB Passive* Incorporated 773 CVV2*112*145*3004 4" CB Passive - Incorporated 774 CW2*112*145*3002 3" SlV w/2" PIPE Passive* Incorporated 775 CW3*112*143*1004 3" CB Passive* Incorporated 776 CW3*112*143*1005 3" x 5" ROUGH OPENING Passive* Incorporated 777 CVV3*112-143-1006 3"CB Passive Incorporated Page 64

NTIF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 Tabla "3: Inspected floodl.. Features Meeti.. ~ptanCli! Criteria Features Immediately Judged liS Ac:teptable No. Feature 1.0. Number Description PassivelActive Incorporated/Temporary 778 CW3-112-143-1007 3" CB Passive Incorporated 779 CW3-112-14HOO8 2" CB Passive Incorporated 780 CW3-11H4HOO9 3" SlV w/1 )1," INS. P Passive Incorporated 781 CW3-112-143-1010 4" SlVw/2" P Passive Incorporated 782 CW3-112-143-1011 4" CB Passive Incorporated 783 CW3-112-143-1012 8" SlV w/4" INS. P Passive - Incorporated 784 CW3-112-14H013 3" C REDUCED TO 1 )1," C ItZD3GOOl PaSSive - Incorporated 785 CW3-112-143-1014 3" C REDUCED TO 1 y," C #2G671 Passive Incorporated 786 CW3-112-143-1015 3" C REDUCED TO 1 Yz" C PaSSive - Incorporated 787 CW3-112*143-1016 3"C Passive* Incorporated 788 CW3*112-143-1017 3" COEw/o PG Passive Incorporated 789 CW3-112-143-1018 4" SlVw/2" P Passive - Incorporated 790 CW3-112-143-1019 4" CB Passive - Incorporated 791 CW3-112-143-1020 6"CB Passive Incorporated 792 CW3-11H43-1021 6"CB Passive - Incorporated 793 CW3-112-143-1022 4"SlV Passive - Incorporated Page 65

NTIF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 Table 13: Inspeded flooding Futures Meeting Acceptance Criteria Features Immediately Judged as AcceptabJe No. Feature 1.0. Number Description Passive/Active Incorporated/Temporary 794 CW3-112-143-1023 12" CB w/l(J' INS. P Passive - Incorporated 795 CW3-112-143-1024 2" CB Passive Incorporated 796 CW3-112-143-1025 2" CB Passive Incorporated 797 CW3-112-143-1026 6" SLV w/3" P Passive -Incorporated 798 CW3-112-143-1027 6" SlV w/2" CU P Passive - Incorporated 799 CW3-112-143-1028 3" SlV w/2" CU P Passive Incorporated 800 CW3-112-143-1029 4" CB Passive Incorporated 801 CW3-112-143-1030 %"C Passive* Incorporated 802 CW3-112-143-1031 2" CB Passive - Incorporated 803 CWH12-143-1032 W' C (DOOR JAMB) Passive -Incorporated 804 CW3-112-143-1033 2" x 4" RECEPTACLE Passive - Incorporated 80S CW3-112-143-1034 10" SLV Passive Incorporated 806 CW3-112-143-1035 4" SLV Passive - Incorporated 807 CW3-112-143-1036 4" SLV Passive Incorporated 808 CWH12-143-1037 12" SLV Passive - Incorporated 809 CWH12-143-1038 1" CB w/CO-X CABLE Passive - Incorporated Page 66

NTTF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 Table 113: I~ flooding Futures MeetIng Acteptante Criteria Features Immediately ludsed as Atteptable No. Feature 1.0. Number Description Passive/Active Incorporated/Temporary Create CRl per IR 1401537 &

810 CW3-112-143-4001 Passive Incorporated ECR 02-00429 (6" Plug)

Create CRl per IR 1401537 &

811 CW3-112-143A002 Passive Incorporated ECR 02*00429 (6" Plug)

Create CRl per IR 1401537 &

812 CW3*112 *143*4003 Passive Incorporated ECR 02*00429 (6" Plug)

Create CRL per IR 1401537 &

813 CW3-112-143-4004 Passive Incorporated ECR 02-00429 (6" Plug) 814 CW3-112*143AOOS 0/." C OE wlo PG w/o CABLE Passive Incorporated 815 CW3-112*143-North Wall North Wall Passive - Incorporated 816 CW3*112*143-West Wall West Wall Passive Incorporated 817 CW3*112-143*1024A 1 )1," ( #203G002 Passive Incorporated 818 CW3*112*143*1025A 1 )1," ( #2B3G004 Passive* Incorporated 819 CW3-112-143-1029A 2" CB Passive Incorporated 127' Diesel Generator 8uilding

Passive Features 820 OGC-127-815-2001 2" CB Passive Incorporated 821 OGC-127-815*2002 2" (B Passive -Incorporated 822 OG(-127-815-2003 2" CB Passive - Incorporated 823 OG(-127-815-2004 2" (B Passive Incorporated 824 OG(-127-815-2005 24"SlVw/20" P Passive -Incorporated 825 DGC-127-815-2006 28" SlV w/24" P Passive - Incorporated Page 67

NTIF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 Table '3: Inspected Flooding Featum MeetillB Acceptance Criteria featulfI$lmmedlately Judged as Acceptable No. Feature 1.0. Number Description Passive/Active Incorporated/Temporary 826 DGC-127-815-2oo7 24" SlV w/20" P Passive - Incorporated 827 OGC-127-815-2008 20" SlV w/16" P Passive - Incorporated 828 OGC-12 7-815-2009 4" SLVw/2" P Passive Incorporated 829 DGC-127-815-2010 4" CB w/2" P Passive Incorporated 830 OGC-127-815-2011 8" CB w/4" P Passive Incorporated 831 OGC-127-815-2012 8" CB w/4" P Passive . Incorporated 832 OGC-127-815-2013 4" SlVw/2" P Passive

Incorporated 833 DGC-127-815-2014 8" CB w/4" P Passive* Incorporated 834 DGC-127-815-2015 8" CB w/4" P Passive Incorporated 835 DGC-127-81S-2016 6" CB w/4" P Passive . Incorporated 836 DGC-127 -815-2017 28" SLV w/24" P Passive Incorporated 837 DGC-127-815-2018 20" SLV w/16" P Passive Incorporated 838 DGC-127-815-2019 3" CB w/1 y," C #2A1892 Passive - Incorporated Create CRl per IR 1401537 &

839 DGC-127-815-2020 Passive

Incorporated ECR 02-00429 Create CRl per IR 1401537 &

840 DGC-127 -815-2021 Passive Incorporated ECR 02-00429 841 DGC-127-815-3001 3" CB w/ 1 y," P Passive* Incorporated

NTIF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5,2012 Table #31 Inspected Flooding' Features Meeting Aeteptance Criteria Features immedIately Judged as Acceptable No. Feature 1.0. Number Description PassivelActive Incorporated/Temporary 842 OGC-127-815-3OO2 3" CBw/1 W' P Passive Incorporated 843 OGC-127-815-3003 3" CB w/l" P Passive Incorporated 844 OGC-127-815-3004 1" C Passive - Incorporated 845 OGC-127-815-4001 24" SLV w/20" P Passive Incorporated 846 DGC-127-815-4002 28" SlV w/24" P Passive - Incorporated 847 DGC-127 -815-4003 24" SlV w/20" P Passive - Incorporated 848 DGC-127-815-4004 20" SlV w/16" P Passive - Incorporated 849 OGC-127-815-4005 4" 5LV w/1)1" C 1t2AL587 Passive Incorporated 850 DGC-127-815-4006 4" 5LV wi 1 X" C 1t2AL592 Passive Incorporated 851 DGC-127-815-4007 3" CO.E. PLUGGED Passive - Incorporated 852 OGC-127-815-4oo8 3" C ItZC2A1595 Passive - Incorporated 853 OGC-127-815-4009 3" C ItZB2A1594 Passive - Incorporated 854 OGC-127-815-4010 3" C ItZB2A1591 Passive - Incorporated 855 OGC-127-815-4011 3" C ItZB2A1590 Passive - Incorporated 856 DGC-127-815-4012 1 W' C #2A1128 Passive Incorporated 857 OGC-127-815-4013 28" SlV w/24" P Passive - Incorporated

NnF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 Table #3: Inspected Flooding Featuru Meeti. Al:(eptance Criteria Featul1l$lmrnediatefy Judged as Acceptable No. Feature 1.0. Number Description PassivelActive Incorporated/Temporary 858 DGC-127 -815-4014 2" P Passive Incorporated 859 DGC*127-81S-4015 8" CB w/4" P Passive Incorporated 860 DGC-127*815*4016 1" C Passive Incorporated 861 DGC*127*815*4017 1" P Passive Incorporated 862 DGC-I27*815*4018 3"5LV Passive -Incorporated 863 DGC-127-815-4019 3" 5lV Passive -Incorporated 864 DGC*127*81S-East Wall East Wall Passive Incorporated 865 DGC*127-815-50uth Wall South Wall Passive Incorporated 866 DGC*127*815*West Wall West Wall Passive . Incorporated 867 DGC-127*815*Slab Slab Passive Incorporated 868 DGC-127*816*200l 4"SLVw/2"P Passive Incorporated 869 DGC-127-816-2002 1 y," P Passive Incorporated 870 DGC*127*816*2003 2" P Passive Incorporated 871 DGC*127-816-2004 1" P Passive* Incorporated 872 DGC*127-816-200S 6" SLV Passive* Incorporated 873 DGC*127-816* 2006 4" CO.E. CAPPED Passive* Incorporated PalZe 70

NTIF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 Table '3: Inspatted Flooding Features Meeting Aceeptanee Criteria Features Imrnedlatety Judged as Aceeptable No. Feature I.D. Number Description PassivelActive Incorporated/Temporary 874 DGC-127-816-2007 W C CARD READER (S-SIDE) Passive Incorporated 875 DGC-127-816-2008 %IfC Passive Incorporated 876 DGC-127-816-2009 y."C Passive Incorporated 877 DGC-12 7-816-4001 2 y," )( 4" OUTLET Passive Incorporated 878 DGC-127-816-West Wall West Wall Passive Incorporated 879 DGC-127-816-East Wall East Wall Passive - Incorporated 880 DGC-127-816-Slab Slab Passive Incorporated 881 OGC-127-817-2001 %,11 C Passive Incorporated 882 DGC-127-817-2002 %,'C Passive Incorporated 883 DGC-127-817-100S Create CRl per IR140153 7 Passive Incorporated 884 DGC-127-817-2006 Create CRL per IR1401537 Passive Incorporated 885 DGC-127-817-2007 Create CRL per IR1401537 Passive Incorporated 886 DGC-127-817-2008 Create CRl per IR1401537 Passive* Incorporated 887 DGC*127*817-2009 Create CRl per IR1401537 Passive Incorporated 888 DGC-127-817-2010 Create CRl per IR1401537 Passive . Incorporated 889 DGC-127-817-4001 1" C Passive Incorporated Page 71

NTIF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 Table 413: Inspected Floodtn, Features Meeting Acceptance Criteria Features Immediately Jud,ed as Acceptable No. Feature 1.0. Number Description PasslvelActive Incorporated/Temporary 890 OGC-127-817-4002 OUTLET Passive - Incorporated 891 OGC-127-817-East Wall East Wall Passive - Incorporated 892 OGC-127-817-West Wall West Wall Passive - Incorporated 893 OGC-127-817-Slab Slab Passive Incorporated 894 OGC-127-818-2001 3" CB Passive -Incorporated 895 OGC-127-818-2002 1" C Passive - Incorporated 896 OGC-127-818-2003 3/4" C Passive - Incorporated 897 OGC-127-818-2004 4" CCAPPED Passive Incorporated 898 OGC-127-818-2005 6" SlV Passive - Incorporated 899 OGC-127-818-2006 3" SlVw/1" P Passive Incorporated 900 OGC-127-818-2007 4" SlVw/2" P Passive -Incorporated 901 OG(-127-818-2008 4" SlV w/1 y," P Passive Incorporated 902 OG(-127-818-2009 4" SlV w/2" P Passive - Incorporated 903 OGC-127-818-4001 %"C Passive - Incorporated Create CRl per IR 1401537 &

904 OGC-127-818-4002 Passive - Incorporated fCR 02-00429 90S OGC-127-818-East Wall East Wall Passive Incorporated

NTIF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 Table IS: Inspected FIoodII'll Features Meetll'll Acceptance eritn Featureslmmed'iately Judged u Acceptable No. Feature 1.0. Number Description Passive!Active Incorporated/Temporary 906 DGC-127-818-West Wall West Wall Passive Incorporated 907 DGC-127-818-Slab Slab Passive - Incorporated 90S DGC-127-S19-1001 X" e.O.£. IN OUTLET BOX Passive - Incorporated 909 DGC-127-S19-2001 3"CB Passive Incorporated 910 DGC-127-S19-2002 3" P EMB Passive Incorporated 911 DGC-127-819-2003 1" C Passive - Incorporated 912 DGC-127-819-2004 X" e.O.E. IN OUTLET BOX Passive Incorporated 913 DGC-127-819-2005 4" CCAPPED Passive Incorporated 914 DGC-127-819-2006 6"SlV Passive Incorporated 915 DGC-127-819-2007 3" SLY w/1" P Passive - Incorporated 916 DGC-127-819-2008 4" SlVw/2" P Passive* Incorporated 917 DGC-127-819-2009 4" SLY w/1 y," P Passive -Incorporated 918 DGC-127-819-2010 4" SLY w/2" P Passive - Incorporated 919 OGC-127-819-2011 W' e.O.E. Passive* Incorporated 920 DGC-127-819-4001 };;" e.O.E. IN OUTLET BOX Passive* Incorporated 921 OGC-127-819-East Wall East Wal! Passive Incorporated Page 73

NTIF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 Table 13; Inspec:tecf flooding Features Meeting Al:ceptance Ctlteria FeaturslfBmedlately Judpd as Acceptable No. Feature 1.0. Number Description Passive/Active Incorporated/Temporary 922 DGC-127-B19-West Wall West Wall Passive Incorporated 923 DGC-127-B19-North Wall North Wall Passive - Incorporated 924 DGC-127-B19-Slab Slab Passive - Incorporated 114' Emergencv Cooling Tower* Passive Features 92S ECT-114-B2B-3001 4" SLY w/2" P Passive - Incorporated 926 ECT-114-B28-3002 28" SLY w/24" P Passive - Incorporated 927 ECT-114-B28-3003 S" CB w/4" C ItZB3A432 Passive Incorporated 928 ECT-114-82B-3004 28" SLY w/24" P Passive - Incorporated 929 ECT-114-828-3005 20" SLY w/16" P Passive - Incorporated 930 ECT-114-828-3006 20" SLY w/16" P Passive - Incorporated 931 ECT-114-828-3007 22" SLY w/18" P Passive Incorporated 932 ECT-114-828-300B 6" e.O.E. PLUGGED SPARE Passive -Incorporated 933 ECH14-828-3009 6" e.O.E. PLUGGED ItZA3A445 Passive Incorporated 934 ECT-114-B28-3010 6" e.O.E. PLUGGED ItZA3A444 Passive Incorporated 935 ECT-114-828-3011 6" e.O.E. PLUGGED ItZA3A443 Passive Incorporated 936 ECT-114-828-3012 6" e.0.E. PLUGGED ItZA3A442 Passive -Incorporated 937 ECT-114-828-3013 6" e.O.E. PLUGGED ItZA3A441 Passive -Incorporated 938 ECT-114-828-Slab Slab Passive -Incorporated 939 ECT-114-B29-East Wall East Wall Passive - Incorporated 940 ECT -114-B29-North Wall North Wall Passive - Incorporated 941 ECT-114-829-South Wall South Wall Passive - Incorporated 942 ECT-114-829-West Wall West Wall Passive - Incorporated Page 74

NTTF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 Table ,I: I~ FloodingFatufft l\lleetlngA~ptant:e Criteria Features Immediately Judged as A<<eptable No. Feature 1.0. Number Description Passive/Active Incorporated/Temporary All ActIVe Featufft 943 Door #032 TB 2 WASTE SLUOGE PUMP ROOM Active Incorporated 944 Ooor#073 U!2 RBCCW ROOM Active Incorporated 945 000r#075 RB 2 BAND D CORE SPRAY ROOM Active Incorporated 946 000r#079 TB 2 COND DEMIN HALLWAY Active Incorporated 947 000r#147 RB 3 A ANO C CORE SPRAY AIRLOCK Active Incorporated 948 Door #144 RB 3 NORTHEAST STAIRWEll Active Incorporated 949 000r#149 U/3 RBCCW ROOM Active Incorporated 950 Door #503 RADWASTE CORR. TO TURBINE BLDG. Active Incorporated 951 Door#COl U/2 HPSW AND ESW PUMP ROOM Active Incorporated 952 Door#C02 U!2 HPSW AND ESW PUMP ROOM Active Incorporated 953 Door#C03 U/2 HPSW AND ESW PUMP ROOM Active Incorporated 954 Door#D01 Equipment Access Door Active - Incorporated 955 Door #D13 ESW BOOSTER PUMP ROOM Active -Incorporated 956 DoorllD02 Equipment Access Door Active - Incorporated E1 STANDBY DIESEl GENERATOR 957 Door #012 Active - Incorporated ROOM 958 Door#D03 Equipment Access Door Active -Incorporated E2 STANDBY DIESEL GENERATOR 959 Door #011 Active Incorporated ROOM 960 Door#D04 Equipment Access Door Active - Incorporated E3 STANDBY OIESEl GENERATOR 961 Door#D10 Active -Incorporated ROOM 962 Door#D05 Equipment Access Door Active -Incorporated E3 STANDBY DIESEl GENERATOR 963 Door#D09 Active - Incorporated ROOM CIRC WATER PP STRUCTURE ROOF 964 HV-0-28A-11443 Active - Incorporated DRAIN TO PP BAY BlK VlV Page 75

NTTF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 Table #3: lnsped;ed Floodi08 Features Meeti08 Acce,tance Criteria Features Immediately Judced as Acceptaole No. Feature 1.0. Number Description PassivelActive Incorporated/Temporary eIRe WATER PP STRUCTURE ROOF 965 HV-0-28A-11444 Active Incorporated DRAIN TO SUMP BLK VLV DIG Bldg. Oily Waste Interceptor Tank 966 HV-0-52-10152 Active Incorporated Inlet Blk 967 MO-2-30-2233A Unit 2 A Sluice Gate Active - Incorporated 968 MO-2-30-2233B Unit 2 B Sluice Gate Active Incorporated 969 MO-3-3Q-3233A Unit 3 A Sluice Gate Active Incorporated 970 MO-3-30-3233B Unit 3 B Sluice Gate Active - Incorporated 971 LS-2278A U2 eiRe. WATER BAY 'N LEVEL Active Incorporated 972 LS-2278B U2 eiRe. WATER BAY 'B' LEVEL Active - Incorporated 973 LS-2278e U2 ClRe. WATER BAY 'C' LEVEL Active Incorporated 974 LS-3278A U3 eiRe. WATER BAY 'A' LEVEL Active - Incorporated 975 LS-3278B U3 eiRe. WATER BAY 'B' LEVEL Active Incorporated 976 LS-3278C U3 eiRe. WATER BAY 'c' LEVEL Active Incorporated Table #4: Inspected Features Not Immediately Judged as Acceptable Flood Features &!tMeeting Acceptance Criteria

Feature ID # Description Observation Component Resolution Operability The stains are trended in the Maintenance Rule structural Yes-see monitoring program established Water Intrusion on Wall showed signs of 1 RB2-091-001-East Wall discussion in in Site Engineering with no East Wall water seepage Resolution column adverse trend noted. There are no existing or historical action requests for this wall.

Page 76

NTTF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 Table 14: tnspKted Futures Not immediately Judcecl IS Acuptabte Rood Futures !2S.MHtlnc AcapUnc.e Cttteria II F ~tur lOll Descrlptlon Observ t50n COmponent Resolution Operability The stains are trended In the Maintenance Rule ructUfilI Yes - see mon Loring progra m established Wier Inl ru~ on on W lishowdslgn5of 2 RBHl9 1-OO1-South W II d n n n Itl! En n rins wlth no Soulh W II wi er p; Resolution column d Be trend noted Th re are no exlstins or historical action requests for t his wall The sta.lns are trended In th Mainlenance Rule Siructur I Yes -s monitoring program est bhshed

~aler Intrusion BaV 1 Wall showed SIlIns of 3 RB2..()gl-OOl -WI!SI W II cfiscussion In in Site Engineering with no Un \ 2 Torus w erseepag R solution column ~d rse trend noted. Th re are no existing or hlstoriQI ct on requests for t his waU.

The sUins are tre nd d in the Maintenance Rule stJuClural Ves - monhorins program established Water Intruslon on Wall showed s ns 0 4 AB3-09HI37-East Wall dlscu slon n in S Ie Ens neerin with no East W JI wal r p ge Rcsolution column d rs Ifend nOled. Th re ar no exlstin or historical action requests for this wall.

Aoor slab showed 34 RHR Room SI b Yes* Documented 5 Rw)..()g1-038* Floor signs of waler Repair per Al822015 91 ' IIlIRl 2564 23 seepa~

3A RHR Room West Wall showed 5i8n5 of Yes-Dotum nted 6 RW3-091-038-West Wall Repa r per A1822015 Wallg1' waler seepage In IR1256423 The stains arc trended in the Maintenance Rule structural Y - See monitoring program established R.eI.C. Pump Ar Floor slab showed 7 RW3*088-047-Floor discusSion en n ite Engineenng with no Room Slab 88' 1lgos or calcificat on Resolution column dverse trend noted. There ar no e. stlng or historical actIon requests for t his wall.

The SUIllS are vended In the Ma intenance Rule struCluT

: Features Clas$lfied as Inaccessible No. Feature 1.0. Number Description Reason Resolution Cable cross-tied among 3" C ZA2A400 to multiple EDG's, always 44 OOC-127-816-5OO4 Reasonable Assurance Documented in IR1402625 OAC97 energized, never out of service Cable cross-tied among mUltiple EDG's, always 45 DGC-127 -816-5005 2" C 2AS32 to OAC97 Reasonable Assurance Documented in IR1402625 energized, never out of service Cable cross-tied among 2" C ZA2A398 to J- multiple EDG's, always 46 DGC-127 -816-5006 Reasonable Assurance Documented in IR1402625 5S9 energized, never out of service Cable cross-tied among multiple EDG's, always 47 DGC-127-816-5007 4" C 2A419 to J-5S9 Reasonable Assurance Documented in IR1402625 energized, never out of service Cable cross-tied among 3" C ZA2A40l to multiple EDG's, always 48 DGC-127-S16-5OOS Reasonable Assurance Documented in IR1402625 00B53 energized, never out of service Cable cross-tied among 4" C ZA2A399 to multiple EDG's, always 49 DGC-127-S16-5009 Reasonable Assurance Documented in Ill. 1402625 00B53 energized, never out of service Cable cross-tied among multiple EDG's, always 50 DGC-127-816-5010 5" CZA2A402 Reasonable Assurance Documented in IR1402625 energized, never out of service Cable cross-tied among mUltiple EDG's, always 51 DGC-127-S16-5011 5" CZA2A403 Reasonable Assurance Documented in IR1402625 energized, never out of service Cable cross-tied among mUltiple EDG's, always 52 DGC-127-816-5012 5" CZA2A404 Reasonable Assurance Documented in Ill. 1402625 energized, never out of service Cable cross-tied among 11/2" C 2A661to multiple EDG's, always 53 DGC-127-S16-5013 Reasonable Assurance Documented in IR1402625 00B53 energized, never out of service Cable cross-tied among mUltiple EDG's, always 54 DGC-127-816-5014 3" C 2AS21 to 00B53 Reasonable Assurance Documented in IR1402625 energized, never out of service Cable cross-tied among 3" C ZA2A1l27 to J- multiple EDG's, always 55 DGC-127-816-5015 Reasonable Assurance Documented in IR1402625 596 energized, never out of service Cable cross-tied among 3" C ZB2A1735 to J- multiple EDG's, always 56 OGC-127-817-500l Reasonable Assurance Documented in IR1402625 1107 energized, never out of service Cable cross-tied among multiple EDG's, always 57 DGC-127-817-5002 3" C OE W/Plug Reasonable Assurance Documented in IR1402625 energized, never out of service Cable cross-tied among 58 OGC-127-817-5OO3 3" C OE W/Plug multiple EDG's, always Reasonable Assurance Documented in IR1402625 energized, never out of Page 94 NTTF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 Table #6: Features Classifil!d as lnac:cessible No. Feature I.D. Number Description Reason Resolution service Cable cross-tied among 3" C ZB2A408 to multiple EOG's, always 59 DGC-127*817*5004 Reasonable Assurance Documented in IR 1402625 OBC97 energized, never out of service Cable cross*tied among multiple EDG's, always 60 DGC-127*817*5005 2" C 2A824 to OBC97 Reasonable Assurance Documented in IR1402625 energized, never out of service Cable cross-tied among 3" C ZB2A41O to J- multiple EDG's, always 61 DGC*127-817*5006 Reasonable Assurance Documented in IR1402625 590 energized, never out of service Cable cross-tied among mUltiple EDG's, always 62 DGC*127*817*5007 4" C 2A416 to J-590 Reasonable Assurance Documented in IR1402625 energized, never out of service Cable cross-tied among 3" C ZB2A411 to multiple EDG's, always 63 DGC-127-817*5008 Reasonable Assurance Documented in IR1402625 00B54 energized, never out of service Cable cross-tied among 3" C ZB2A409 to mUltiple EDG's, always 64 DGC-127-817*5009 Reasonable Assurance Documented in IR1402625 00B54 energized, never out of service Cable crosNied among multiple EDG's, always 65 DGC*127-817-501O 5" C ZB2A405 Reasonable Assurance Documented in IR140262S energized, never out of service Cable cross-tied among multiple EDG's, always 66 DGC-127*817-S011 5" CZB2A406 Reasonable Assurance Documented in IR1402625 energized, never out of service Cable cross*tied among multiple EDG's, always 67 DGC-127-817-5012 5" CZB2A407 Reasonable Assurance Documented in IR1402625 energized, never out of service Cable cross-tied among 3" C ZB2A1126 to J- multiple EDG's, always 68 DGC-127-817-5013 Reasonable Assurance Documented in IR1402625 595 energized, never out of service Cable cross-tied among 2" C 2A581 to PAB multiple EDG's, always 69 DGC-12H17-5014 Reasonable Assurance Documented in IR 1402625 CABINET energized, never out of service Cable cross-tied among 2" C 2A582 to PAB multiple EDG's, always 70 DGC*127*817-S015 Reasonable Assurance Documented in IR1402625 CABINET energized, never out of service Cable cross-tied among multiple EDG's, always 71 DGC-127*817-5016 2" C SPARE Reasonable Assurance Documented in IR1402625 energized, never out of service Major eqUipment Reasonable Assurance Documented in E-1315, 72 DGC-127-818-2001A Internal Conduit Seal disassembly to access accessed 3 locations and verified. NTIF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 Table 116: Features Claslifted a$lm'lcces$lble No. Feature 1.0. Number Description Reason Resolution Cable cross-tied among 3" CZC2A1733 to J- multiple EOG's, always 73 OGC-127-818-5001 Reasonable Assurance Documented in IR1402625 1108 energized, never out of service Cable cross-tied among multiple EOG's, always 74 OGC-127-818-5002 3" C OE W /Plug Reasonable Assurance Documented in IR1402625 energized, never out of service Cable cross-tied among mUltiple EDG's, always 75 OGC-127-818-5003 3" C OE W /Plug Reasonable Assurance Documented in IR1402625 energized, never out of service Cable cross-tied among 3" C ZC2A432 to multiple EDG's, always 76 OGC-127-818-5004 Reasonable Assurance Documented in IR1402625 OCC97 energized, never out of service Cable cross-tied among mUltiple EDG's, always 77 OGC-127-818-500S 2" C 2A825 to OCC97 Reasonable Assurance Documented in IR1402625 energized, never out of service Cable cross-tied among 3" C ZC2A430 to J- multiple EDG's, always 78 DGC-127-818-S006 Reasonable Assurance Documented in IR1402625 591 energized, never out of service Cable cross-tied among multiple EOG's, always 79 DGC-127-818-5007 4" C 2A417 to J-591 Reasonable Assurance Documented in IR1402625 energized, never out of service Cable cross-tied among 3" C ZC2A431 to multiple EDG's, always 80 OGC-127-818-S008 Reasonable Assurance Documented in IR1402625 OOBSS energized, never out of service Cable cross-tied among 3" C ZC2A433 to mUltiple EDG's, always 81 OGC-127-818-S009 Reasonable Assurance Documented in IR1402625 00B55 energized, never out of service Cable cross-tied among multiple EOG's, always 82 OGC-127-818-501O S" CZC2A427 Reasonable Assurance Documented in IR1402625 energized, never out of service Cable cross-tied among multiple EDG's, always 83 OGC-127-818-5011 S" CZC2A428 Reasonable Assurance Documented in IR1402625 energized, never out of service Cable cross-tied among multiple EOG's, always 84 OGC-127-818-5012 5" C ZC2A429 Reasonable Assurance Documented in IR140262S energized, never out of service Cable cross-tied among 3" C 2A 703 to 71l multiple EDG's, always 85 OGC-127-818-S013 Reasonable Assurance Documented in IR1402625 PANEL energized, never out of service Cable cross-tied among multiple EDG's, always 86 DGC-127-818-5014 3"C2A549 Reasonable Assurance Documented in IR1402625 energized, never out of service Cable cross-tied among 3" C 2A5S0 to F/A 87 OGC-127-818-5015 multiple EDG's, always Reasonable Assurance Documented in IR1402625 CAB #1 energized, never out of Page 96 NTIF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 Table #&~'dtures Clamtied aSINlI:CeS$lble No. feature 1.0. Number Description Reason Resolution service Cable cross"tied among 4" C 2M13 to EtA multiple EOG's, always 88 DGC-127-818-5016 Reasonable Assurance Documented in IR1402625 CAB #1 energized, never out of service Cable cross-tied among 3" C ZC2A1125 to J- multiple EOG's, always 89 DGC-127-818-5017 Reasonable Assurance Documented in IR1402625 594 energized, never out of service Major equipment Reasonable Assurance Documented in E-1315, 90 DGC-127-819-2001A Internal Conduit Seal disassembly to access accessed 3 locations and verified. Cable cross-tied among 3" C ZD2A1734 to J- multiple EOG's, always 91 DGC-127-819-5001 Reasonable Assurance Documented in IR1402625 1109 energized, never out of service Cable cross-tied among multiple EDG's, always 92 DGC-127-819-5002 3" C OF W/Plug Reasonable Assurance Documented in IR1402625 energized, never out of service Cable cross-tied among multiple EOG's, always 93 DGC-127-819-5003 3" C OE W /Plug Reasonable Assurance Documented in IR1402625 energized, never out of service Cable cross-tied among 3" C ZD2A391 to multiple EDG's, always 94 DGC-127-819-5004 Reasonable Assurance Documented in IR1402625 ODC97 energized, never out of service Cable cross-tied among mUltiple EOG's, always 95 DGC-127-819-5005 2" C 2A826 to ODC97 Reasonable Assurance Documented in IR1402625 energized, never out of service Cable cross-tied among 3" C ZD2A393 to J- multiple EDG's, always 96 DGC-127-819-5006 Reasonable Assurance Documented in IR 1402625 592 energized, never out of service Cable cross-tied among mUltiple EDG's, always 97 DGC-127-819-5007 5" C 2A412 to J-592 Reasonable Assurance Documented in IR1402625 energized, never out of service Cable cross-tied among multiple EDG's, always 98 DGC-127-819-5008 4" C 2M15 to J-592 Reasonable Assurance Documented in IR1402625 energized, never out of service Cable cross-tied among multiple EOG's, always 99 DGC-127-819-5009 3" C 2A394 to 00B56 Reasonable Assurance Documented in IR 1402625 energized, never out of service Cable cross-tied among multiple EDG's, always 100 DGC-127-819-5010 4" C 2A392 to 00856 Reasonable Assurance Documented in IR1402625 energized, never out of service Cable cross-tied among multiple EOG's, always 101 DGC-127 -819-5011 5" CZD2A395 Reasonable Assurance Documented in IR1402625 energized, never out of service Page 97 NTIF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012 Table 116: features Classified as Inaccessible No. Feature 1.0. Number Description Reason Resolution Cable cross-tied among multiple EDG's, always 102 DGC*127-819-5012 5" CZD2A396 Reasonable Assurance Documented in IR1402625 energized, never out of service Cable cross-tied among multiple EDG's, always 103 DGC*127-819-5013 5" CZD2A397 Reasonable Assurance Documented in IR1402625 energized, never out of service Cable cross-tied among multiple EDG's, always 104 DGC-127-819-5014 4" C 2A418 TO J*593 Reasonable Assurance Documented in IR1402625 energized, never out of service Cable cross-tied among 3" C ZD2A1124 TO J- multiple EDG's, always 105 DGC-127-819-S01S Reasonable Assurance Documented in IR1402625 593 energized, never out of service 114' Emergency CoolingTower Reasonable Assurance Documented in IR 12" P EMS. 106 ECT-114-829-3001 Underground 01393061 and inspected similar penetration OVERFLOW seals in ECT Room 828

1. Exelon letter to U.S, Nuclear Regulatory Commission. Exelon Generation Company, LLe's 90-Day Response to March 12, 2012 Request for Informatian Pursuant to Title 10 of the Code of Federal Regulations 50.54(f) Regarding Recommendations 2.1 and 2.3, of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident (Flooding). June 11, 2012.

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

3. U.s. Nuclear Regulatory Commission. letter to licensees. 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. March 12,2012.

4. U.S. Nuclear Regulatory Commission. Demonstrating the Feasibility and Reliability of Operator Manual Actions in Response to Fire. NUREG-1852. October 2007.

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-ichi Accident. 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. Page 98 NTTF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012

7. Institute of Nuclear Power Operations. Fukushima Dai-ichi Nuclear Station Fuel Damage Caused by Earthquake and Tsunami. INPO Event Report 11-1. March 15, 2011.

8. U.S. Nuclear Regulatory Commission. Follow-up to the Fukushima Dai-ichi Nuclear Station Fuel Damage Event. Inspection Manual. Temporary Instruction 2515/183. ML113220407. November 2011.

9. U.S. Nuclear Regulatory Commission. Inspection of Structures, Passive Components, and Civil Engineering Features at Nuclear Pawer Plants. Inspection Manual. Inspection Procedure 62002.

Section 03.01(h), Dams, Embankments and Canals.

10. U.s. Nuclear Regulatory Commission. Evaluate Readiness to Cope with External Flooding. Inspection Procedures. Attachment 71111.01. Adverse Weather Protection. Section 02.04.

11. U.S. Nuclear Regulatory Commission. NRC Inspector Field Observation Best Practices. NUREG/BR-0326, Rev. 1. August 2009.

12. U.S. Nuclear Regulatory Commission. Flaod Pratection for Nuclear Power Plants. Regulatory Guide 1.102.

13. PBAPS UFSAR, Rev. 23, Sections 2.4 and 12.2

14. SE-4 Flood Procedure, Rev. 32

15. P-T-Ol, Rev. 8, Structural Design Basis Document - PBAPS Units 2 and 3

16. P-T-07, Rev. 2, External Hazard Design Basis Document - PBAPS Units 2 and 3

17. PS- Series Penetration Drawings

18. A-484, Sht. 1, Rev. 6, Barrier Plan Elev. 91'-6"

19. A-485, Sht. 1, Rev. 8, Barrier Plan Elev. 116'-0"

20. A-490, Sht. 1, Rev. 4, Barrier Plans C.W. Pump Structure, Emergency Cooling Tower & Diesel Generator Building

21. ER-PB-450-1006, Rev. 1, Peach Bottom Structures Monitoring Instructions

22. AO 20A.1, Rev. 14, Temporary Removal and Installation of Flood Barriers in the Reactor Building Drainage System

23. RT-W-020-930-2, Rev. 4, Survey for Flood Barriers in Reactor Building Drainage System (Unit 2)

24. RT-W-020-930-3, Rev. 4, Survey for Flood Barriers in Reactor Building Drainage System (Unit 3)

25. RT-M-045-980-2, Rev. 4, Water Tight Door Survey

26. RT-M-045-990-2, Rev. 1, Water Tight Diesel Equipment Access Door Survey

27. CC-PB-201, Rev. 0, Hazard Barrier Control Program

28. AO 28.2, Rev. 2, Response to High/Low River Level

29. Supplemental Walkdown/lnspection Guidance, Rev. 1,8/17/12

30. GP-3, Rev. 127, Normal Plant Shutdown

31. GP-4, Rev. 4, Manual Reactor Scram Page 99

NTIF Recommendation 2.3 (Walkdowns): Flooding Exelon Corporation November 5, 2012

32. NE~075, Rev. 4, Specification for Penetration Seals in Hazard Barriers at Peach Bottom Atomic Power Station and Limerick Generating Station

33. SO 48.1.B Emergency Cooling Water System Startup, Rev. 14

34. PBAPS Technical Requirements Manual for both Units 2 and 3, Section 3.15, River Level

35. PBAPS Technical Requirements Manual for both Units 2 and 3, Section 3.7, River Level Instrumentation

36. IR 01414866 Fukushima ~ Flood WID'S - Valves not Stroked Periodically

37. IR 1435150 - Flood Procedure Improvement Details Page 100

U.S. Nuclear Regulatory Commission 180-0ay Response to 50.54(f) Letter NTTF Recommendation 2.3: Flooding November 19, 2012 Page 6 Enclosure 2

SUMMARY

OF REGULATORY COMMITMENTS The following table identifies commitments made in this document. (Any other actions discussed in the submittal represent intended or planned actions. They are described to the NRC for the NRC's information and are not regulatory commitments.)

COMMITIED COMMITMENT TYPE COMMITMENT DATE OR ONE-TIME ACTION PROGRAMMATIC "OUTAGE" (Yes/No) (Yes/No)

Exelon Generation Company, LLC (EGC) will P3R20 Yes No complete the walkdown of the PBAPS Unit 2 Fall 2015

& 3 items classified as restricted access (ref:

PBAPS Report Table #5).

RS-12-174, Company, Llc'S 180-day Response to NRC Request for Information Pursuant to 10 CFR 50.54(f) Regarding the Flooding Aspects of Recommendation 2.3 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident

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Text

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References:

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RS-12-174, Company, Llc'S 180-day Response to NRC Request for Information Pursuant to 10 CFR 50.54(f) Regarding the Flooding Aspects of Recommendation 2.3 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident

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Subject:

References:

Enclosures:

SUMMARY

SUMMARY

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