Text

Table B-2 Nuclear Safety Capability Assessment Methodology Review
	ML11276A121
Person / Time
Site:	Fort Calhoun
Issue date:	09/28/2011
From:	; Omaha Public Power District
To:	; Office of Nuclear Reactor Regulation
References
	LIC-11-0099
	Download: ML11276A121 (229)
	v • d • e

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.1 Nuclear Safety Capability System and Equipment Selection NEI 00-01 Section 3.0 Guidance 3.1.3.2 Identify Combinations of Given the criteria/assumptions defined in Section 3.1.1, identify the available combinations of systems capable of achieving the safe Systems That Satisfy Each shutdown functions of reactivity control, pressure control, inventory control, decay heat removal, process monitoring and support Safe Shutdown Function systems such as electrical and cooling systems (refer to Section 3.1.2). This selection process does not restrict the use of other systems. In addition to achieving the required safe shutdown functions, consider spurious operations and power supply issues that could impact the required safe shutdown function.

ADolicabilitv Comments Applicable Alignment Statement Aligns Alianment Basis Engineering analysis EA10-036, Attachment 1:

Engineering analysis EA10-036, Attachment 1 outlines the safe shutdown functions and systems that fulfill the safe shutdown performance criteria. The functions are defined as follows:

- Reactivity Control

- Inventory and Pressure Control

- Decay Heat Removal

- Vital Auxiliaries

- Process Monitoring This document includes supporting components when required for proper operation. Associated circuits by spurious operation (generally controllers, relays or interlocks found on the circuit schematics) are captured in cable logics or supporting component logics; these relationships are described in this document, and are determined in the component and cable selection process. Power supplies are also determined as part of component and cable selection, but are generally not described in this document. Power supply relationships are also identified using supporting component logics, which are documented in Attachment 6 to engineering analysis EA10-036. Credit is not taken for spurious operation of automatic signals which aid in performing the safe shutdown function.

Comments Reference Document DochDetails FCS Engineering Analysis EA10-036 Attachments 1 and 6 Page B-41

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.1 Nuclear Safety Capability System and Equipment Selection NEI00-01 Ref NEI 00-01 Section 3.0 Guidance 3.1.3.3 Define Combination of Select combinations of systems with the capability of performing all of the required safe shutdown functions and designate this set of Systems for Each Safe systems as a safe shutdown path. In many cases, paths may be defined on a divisional basis since the availability of electrical power Shutdown Path and other support systems must be demonstrated for each path. During the equipment selection phase, identify any additional support systems and list them for the appropriate path.

Aoolicabilitv Comments Applicable Alignment Statement Aligns Alignment Basis Engineering analysis EA10-036, Attachments 3 and 5: of engineering analysis EA10-036 identifies the NFPA 805 performance goals that represent the safe shutdown functions that are modeled. For each performance goal, path numbers are assigned to each combination of safe shutdown systems that are required to fulfill the safe shutdown function. The logic diagrams (engineering analysis EA10-036, Attachment 5) illustrate the various interrelationships between systems and can be used to determine the combinations of systems required to achieve safe shutdown on a fire area basis.

Comments Reference Document Doc. Details FCS Engineering Analysis EA10-036 Attachments 3 and 5 Page B-42

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.1 Nuclear Safety Capability System and Equipment Selection NEI 00-01 Ref NEI 00-01 Section 3.0 Guidance 3.1.3.4 Assign Shutdown Paths to Assign a path designation to each combination of systems. The path will serve to document the combination of systems relied upon for Each Combination of safe shutdown in each fire area. Refer to Attachment 1 to this document for an example of a table illustrating how to document the Systems various combinations of systems for selected shutdown paths.

Aolabilitv Comments Applicable Alignment Statement Aligns Alignment Basis Engineering analysis EA10-036, Attachments 3 and 5: of engineering analysis EA10-036 identifies the NFPA 805 performance goals that represent the safe shutdown functions that are modeled. For each performance goal, path numbers are assigned to each combination of safe shutdown systems that are required to fulfill the safe shutdown function. The logic diagrams (engineering analysis EA10-036, Attachment 5) illustrate the various interrelationships between systems and can be used to determine the combinations of systems required to achieve safe shutdown on a fire area basis. Fire area assessments using a relational database determine which systems are available for a given fire area.

Comments Reference Document Doc, Details FCS Engineering Analysis EA10-036 Attachments 3 and 5 Page B-43

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.1 Nuclear Safety Capability System and Equipment Selection NEI00-01 Ref NEI 00-01 Section 3.0 Guidance 3.2 Safe Shutdown Equipment The previous section described the methodology for selecting the systems and paths necessary to achieve and maintain safe Selection shutdown for an exposure fire event (see Section 5.0 DEFINITIONS for "Exposure Fire"). This section describes the criteria/assumptions and selection methodology for identifying the specific safe shutdown equipment necessary for the systems to perform their Appendix R function.

The selected equipment should be related back to the safe shutdown systems that they support and be assigned to the same safe shutdown path as that system. The list of safe shutdown equipment will then form the basis for identifying the cables necessary for the operation or that can cause the maloperation of the safe shutdown systems.

Applicable Alignment Statement Not Required Alianment Basis Generic paragraph. Detailed alignment discussed in subsequent reference paragraphs.

Comments Reference Document Doc. Details Page B-44

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.1 Nuclear Safety Capability System and Equipment Selection NEI 00-01 Rf NEI 00-01 Section 3.0 Guidance 3.2.1 Criteria/Assumptions Consider the following criteria and assumptions when identifying equipment necessary to perform the required safe shutdown functions:

Alicabilitv Comments Applicable Alignment Statement Not Required Alianment Basis Generic paragraph. Detailed alignment discussed in subsequent reference paragraphs.

Comments Reference Document Doc, Details Page B-45

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.1 Nuclear Safety Capability System and Equipment Selection NE100-01 Ref NEI 00-01 Section 3.0 Guidance 3.2.1.1 Criteria/Assumptions Safe shutdown equipment can be divided into two categories. Equipment may be categorized as (1) primary components or (2) secondary components. Typically, the following types of equipment are considered to be primary components:

- Pumps, motor operated valves, solenoid valves, fans, gas bottles, dampers, unit coolers, etc.

- All necessary process indicators and recorders (i.e., flow indicator, temperature indicator, turbine speed indicator, pressure indicator, level recorder)

- Power supplies or other electrical components that support operation of primary components (i.e., diesel generators, switchgear, motor control centers, load centers, power supplies, distribution panels, etc.).

Secondary components are typically items found within the circuitry for a primary component. These provide a supporting role to the overall circuit function. Some secondary components may provide an isolation function or a signal to a primary component via either an interlock or input signal processor. Examples of secondary components include flow switches, pressure switches, temperature switches, level switches, temperature elements, speed elements, transmitters, converters, controllers, transducers, signal conditioners, hand switches, relays, fuses and various instrumentation devices.

Determine which equipment should be included on the Safe Shutdown Equipment List (SSEL). As an option, include secondary components with a primary component(s) that would be affected by fire damage to the secondary component. By doing this, the SSEL can be kept to a manageable size and the equipment included on the SSEL can be readily related to required post-fire safe shutdown systems and functions.

Applicability Comments Applicable Alignment Statement Aligns Allanment Basis Equipment selection efforts were completed consistent with FCS engineering analysis EA10-036, Attachment 14 (the procedure for post fire safe shutdown/Fire PRA component identification). The procedure was developed using guidance from Section 3.0 of NEI 00-01.

Engineering analysis EA10-036: 4, Section 5.2:

"The validation activity for SSEL components will be performed through a review of flow paths for systems and system boundaries. Components in the flow paths that require operation/repositioning to allow the system to function, and components that could spuriously operate and impair safe shutdown shall be identified/verified and included in the Page B-46

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.1 Nuclear Safety Capability System and Equipment Selection SSEL. Support system (e.g., electrical power and control, instrumentation, instrument air, cooling and ventilation, etc.) components shall also be included in the SSEL.

Components from the SSEL that are validated and determined necessary to support the nuclear safety objectives will be designated as safe shutdown equipment.

5.2.1 All pumps and fans required to fulfill the safe shutdown success criteria shall be included. This includes loads that should be secured to ensure the success criteria.

5.2.2 Valves/ dampers (including fire dampers)/ support system components required to fulfill safe shutdown success criteria shall be included.

5.2.3 Valves/ dampers constituting system boundaries should be included in the SSEL. Normally closed manual valves and properly oriented check valves credited as system boundaries are not required to be listed in the SSEL.

5.2.4 Manual drain, vent, and instrument root valves are not required for post-fire safe shutdown operation and should not be included in the SSEL.

5.2.5 Valves/dampers (including fire dampers) in the flow path whose spurious operation could adversely affect system operation shall be included in the SSEL. Manual valves/dampers requiring repositioning during the post-fire shutdown should also be included. Properly positioned manual valves and dampers, and properly oriented check valves in the flow path that do not require manual actions or re-positioning during the post-fire shutdown should not be included in the SSEL.

5.2.6 Safety/Relief valves provided for equipment and piping protection should not be included. However, safety/relief valves providing an active safe shutdown function, such as atmospheric dump valves and power operated relief valves, shall be included. Also, safety/relief valves that provide high-low pressure interface shall be included.

5.2.7 Loops or bypasses within a system where spurious operation would not result in a loss of flow or inadequate flow to safe shutdown success paths should not be included in the SSEL. The basis for not including these bypasses shall be documented and supported by a calculation, or addressed in an engineering evaluation, where required.

5.2.8 For tanks, all outlet lines should be evaluated for their functional requirements. For lines not required to be functional, a means of isolation should be included when necessary to prevent unnecessary drawdown of the tank. Tank fill lines should also be evaluated as necessary. The basis for not including an outlet and/or fill line shall be documented and supported by a calculation, or addressed in an engineering evaluation, where required.

5.2.9 Steam traps in the safe shutdown flow path, designed to remove condensate and trap steam, should not be included in the SSEL. Based on this design function, steam exiting via these flow paths is considered to have a negligible impact on RCS cooldown and secondary inventory control.

5.2.10 Interrelated circuitry, which may be identified on the P&IDs by dashed lines between safe shutdown components and safe shutdown/non-safe shutdown components, should be reviewed to identify potential additional components that may affect safe shutdown. These components shall be included in the SSEL as appropriate.

It should be noted that interrelated circuits as identified on the P&IDs are not all inclusive. Electrical drawings and other design documents should also be reviewed to completely identify such additional components.

5.2.11 Instrument air piping and components (e.g., accumulators) should be considered for viability during and after the fire in providing the motive force for credited components.

5.2.12 Pilot valves shall not be listed in the SSEL. The process valve with which the pilot valves are associated shall be identified in the SSEL. Solenoid valves related with the process valves shall be included in the SSEL and the process valves they are identified with shall be included in the SSEL.

5.2.13 Components for functions not involving mechanical/fluid flow paths (e.g., process monitoring and other support systems) shall be identified. The following guidelines should be used:

-For the process monitoring function, the guidance provided in NEI 00-01 shall be used in the identification of the minimum set of instruments that are required to monitor Plant process variables. In addition, diagnostic and monitoring instrumentation for existing manual actions shall be reviewed and included if that manual action is still a valid action.

-Instruments included in the SSEL shall be consistently identified. The instrument shall be identified as the Equipment ID for the display or control device. All other subcomponents (Pressure Transmitter, Pressure Switch, etc.) are not required to be identified separately (this is preferred to keep the SSEL to a manageable list). Any subcomponents are tied to the primary component (display device) by the circuit analysis process and the association of required cables to the components on the SSEL.

Example: Instrumentation components that are used for display or readout (e.g., indicator or recorder), for an action (e.g., hand indicating controller, auto/manual controller), for auto process control (e.g., auto-pressure controller), etc. shall be included in the SSEL. Other support components within the instrument loop (e.g., loop processor like summator, loop power supply module, etc.) need not be included. All power supplies to a loop, including power supply to a recorder, must be included.

Transmitters may be used as a subcomponent to represent/ collect the location(s) of the instrument sensing lines."

Despite what Attachment 14 to engineering analysis EA10-036 identifies as a guideline for the identification of instrumentation in the analysis, the FCS NFPA 805 safe shutdown model identifies instrumentation with the key ID being the database ID for the transmitter (i.e., A/PT-1 02 rather than the indicator). This minor difference was determined to be Page B-47

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.1 Nuclear Safety Capability System and Equipment Selection acceptable for the transition to NFPA 805 in order to maintain consistency with the naming convention previously established in the FCS 10 CFR 50 Appendix R safe shutdown model. 4, Section 5.2:

"-Electrical onsite power components (including alternative or dedicated) associated with safe shutdown requirements shall be identified in the SSEL.

Electrical components, as a minimum, shall be identified at the bus level (e.g., 4160V Bus, MCC, Load Center, and Distribution Panel) and at the equipment level (e.g., power transformer, distribution transformer, battery, battery charger, inverter, power transfer switch, isolation cabinet, sequencer panel, etc.). Subcomponents may be identified with the primary component and the rationale/ methodology documented." 4, Section 5.2:

"-Off-site power can be used as a source of power for Safe Shutdown equipment. All equipment required to support the portion of off-site power relied upon to achieve the nuclear safety performance criteria should also be identified.

-Mechanical components susceptible to fire damage (some soldered instrument lines, instrument tubing for credited instruments may be subject to inaccurate indication) shall be identified and evaluated on a fire area basis. This may take the form of a standalone evaluation or may be incorporated into the SSEL and fire area compliance strategies."

The safe shutdown analysis for NFPA 805 includes an assessment of fire effects to Instrument Tubing Sense Lines, contained in Attachment 10 to engineering analysis EA10-036. The attachment documents the methodology and the results of the assessment.

The list of equipment credited for safe shutdown is Attachment 2 to engineering analysis EA10-036. The list was developed in accordance with the guidelines of Attachment 14 of engineering analysis EA10-036.

Comments Reference Document Doc. Details FCS Engineering Analysis EA10-036 Attachments 2 and 10 Attachment 14, Section 5.2 Page B-48

Omaha Public Power District FCS NFPA 805 TransitionReport Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.1 Nuclear Safety Capability System and Equipment Selection NEI 00-01 Section 3.0 Guidance 3.2.1.2 Criteria/Assumptions Assume that exposure fire damage to manual valves and piping does not adversely impact their ability to perform their pressure boundary or safe shutdown function (heat sensitive piping materials, including tubing with brazed or soldered joints, are not included in this assumption). Fire damage should be evaluated with respect to the ability to manually open or close the valve should this be necessary as a part of the post-fire safe shutdown scenario.

Apolicabili Comments Applicable Alignment Statement Aligns Alionment Basis Engineering analysis EA10-036, Assumption 4.2.9 "Exposure fire damage to manual valves and piping does not adversely impact their ability to perform their pressure boundary or safe shutdown function (heat sensitive piping materials, including tubing with brazed or soldered joints, are not included in this assumption). Fire damage shall be evaluated with respect to the ability to manually open or close the valve should this be necessary as a part of the post-fire safe shutdown scenario."

Comments Reference Document DocA Details FCS Engineering Analysis EA10-036 Assumption 4.2.9 Page B-49

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.1 Nuclear Safety Capability System and Equipment Selection NEI 00-01 Section 3.0 Guidance 3.2.1.3 Criteria/Assumptions Assume that manual valves are in their normal position as shown on P&IDs or in the plant operating procedures.

Aoolicabilit Comments Applicable Alignment Statement Aligns Alianment Basis Engineering analysis EA10-036, Assumption 4.2.2 "Plant equipment is assumed to be in its normal expected position or condition at the onset of the fire (with the plant at power operation). In cases where the status of equipment is indeterminate or could change as a result of expected plant conditions, worst-case initial conditions are assumed for the purpose of cable selection. The normal position for equipment and references are identified in Attachment 2, "Combined Appendix R and NFPA 805 Nuclear Safety Performance Criteria Equipment List"."

Engineering analysis EA10-036, Attachment 1, "Notes":

"-All manual valves are assumed to be inthe normal, at-power position, as shown on the respective Piping and Instrumentation Diagram (P&ID) or as indicated in other plant documentation."

Reference Document Doc. Details FCS Engineering Analysis EA10-036 Assumption 4.2.2 Attachment 1, "Notes" Page B-50

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.1 Nuclear Safety Capability System and Equipment Selection NEI 00-01 Section 3.0 Guidance 3.2.1.4 Criteria/Assumptions Assume that a check valve closes in the direction of potential flow diversion and seats properly with sufficient leak tightness to prevent flow diversion. Therefore, check valves do not adversely affect the flow rate capability of the safe shutdown systems being used for inventory control, decay heat removal, equipment cooling or other related safe shutdown functions.

Alablitv Comments Applicable Alignment Statement Aligns with Intent Alignment Basis Engineering analysis EA10-036, Attachment 14, Section 5.2.3:

"Valves/dampers constituting system boundaries should be included in the SSEL. Normally closed manual valves and properly oriented check valves credited as system boundaries are not required to be listed in the SSEL."

This guideline indicates that check valves do not adversely affect the proper flow paths, and can be credited as system boundaries.

Comments Reference Document Doc. Details FCS Engineering Analysis EAIO-036 Attachment 14, Section 5.2.3 Page B-51

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.1 Nuclear Safety Capability System and Equipment Selection NEI 00-01 RQf NEI 00-01 Section 3.0 Guidance 3.2.1.5 Criteria/Assumptions Instruments (e.g., resistance temperature detectors, thermocouples, pressure transmitters, and flow transmitters) are assumed to fail upscale, midscale, or downscale as a result of fire damage, whichever is worse. An instrument performing a control function is assumed to provide an undesired signal to the control circuit.

Aoicabilitv Applicable Alignment Statement Aligns Alignment Basis Engineering analysis EA10-036, Assumption 4.2.11:

"Instruments (e.g., resistance temperature detectors, thermocouples, pressure transmitters, and flow transmitters) are assumed to fail upscale, midscale, or downscale as a result of fire damage, whichever is worse. An instrument performing a control function is assumed to provide an undesired signal to the circuit."

Reference Document Doc. Details FCS Engineering Analysis EA10-036 Assumption 4.2.11 Page B-52

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.1 Nuclear Safety Capability System and Equipment Selection NEI 00-01 Section 3.0 Guidance 3.2.1.6 Criteria/Assumptions Identify equipment that could spuriously operate or mal-operate and impact the performance of equipment on a required safe shutdown path during the equipment selection phase. Consider Bin 1 of RIS 2004-03 during the equipment identification process.

Applicability Applicable Alignment Statement Aligns Alignment Basis Engineering analysis EA10-036, Attachment 14, Section 5.2:

"Components in the flow paths that require operation/repositioning to allow the system to function, and components that could spuriously operate and impair safe shutdown shall be identified/verified and included in the SSEL."

Regarding the consideration of RIS 2004-03 Bin 1, the equipment selection methodology utilized for the Fort Calhoun NFPA 805 Transition Project does not incorporate any binning process, and does not place any limit upon the number of, or combination of concurrent spurious component operations that are to be assumed by the analyst, in accordance with Assumption 4.2.12 of engineering analysis EA10-036. Consequently, the methodology is more conservative than the prescribed guidance. The identification of equipment that could spuriously operate and impact the performance of safe shutdown functions is an inherent part of the equipment selection and circuit analysis processes.

Comments Reference Document Doc. Details FCS Engineering Analysis EAI0-036 Assumption 4.2.12 Attachment 14, Section 5.2 Page B-53

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.1 Nuclear Safety Capability System and Equipment Selection NEI 00-01 Ref NEI 00-01 Section 3.0 Guidance 3.2.1.7 Criteria/Assumptions Identify instrument tubing that may cause subsequent effects on instrument readings or signals as a result of fire. Determine and consider the fire area location of the instrument tubing when evaluating the effects of fire damage to circuits and equipment in the fire area.

A laklic l Comments Applicable Alignment Statement Aligns Alignment Basis See Alignment Basis for NEI 00-01 Section 3.4.1.8.

Comments Reference Document Doc. Details Page B-54

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.1 Nuclear Safety Capability System and Equipment Selection NEI 00-01 Ref NEI 00-01 Section 3.0 Guidance 3.2.2 Methodology for Refer to NEI 00-01 Rev 1 Figure 3-3 for a flowchart illustrating the various steps involved in selecting safe shutdown equipment.

Equipment Selection Use the following methodology to select the safe shutdown equipment for a post-fire safe shutdown analysis:

Aoilicabiliv Comments Applicable Alignment Statement Not Required Alignment Basis Generic paragraph. Detailed alignment discussed in subsequent reference paragraphs.

Comments Reference Document Doc. Details Page B-55

Omaha Public PowerDistrict FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.1 Nuclear Safety Capability System and Equipment Selection NEI 00-01 fRL NEI 00-01 Section 3.0 Guidance 3.2.2.1 Identify the System Flow Mark up and annotate a P&ID to highlight the specific flow paths for each system in support of each shutdown path. Refer to Path for Each Shutdown Attachment 2 for an example of an annotated P&ID illustrating this concept.

Path Anplicabilt Comments Applicable Alignment Statement Aligns with Intent Alignment Basis Engineering analysis EA10-036, Attachment 14, Section 5.2:

"Based upon plant P&IDs, components on the SSEL for the subject system(s) will be reviewed to identify that they are necessary to support the nuclear safety objectives."

"The validation activity for SSEL components will be performed through a review of flow paths for systems and system boundaries."

The methodology used in the development of the list of credited safe shutdown equipment and validation of system lineups credits the review of plant P&IDs. Though P&IDs were not marked up or annotated to be maintained as basis for system selection, the methodology aligns with the intent of the guidance to ensure that system lineups are verified using the appropriate drawings.

Comments Reference Document Doc. Details FCS Engineering Analysis EA10-036 Attachment 14, Section 5.2 Page B-56

Omaha Public PowerDistrict FCS NFPA 805 TransitionReport Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.1 Nuclear Safety Capability System and Equipment Selection NEI 00-01 Section 3.0 Guidance 3.2.2.2 Identify the Equipment in Review the applicable documentation (e.g. P&IDs, electrical drawings, instrument loop diagrams) to assure that all equipment in each Each Safe Shutdown system's flow path has been identified. Assure that any equipment that could spuriously operate and adversely affect the desired System Flow Path system function(s) is also identified. If additional systems are identified which are necessary for the operation of the safe shutdown Including Equipment That system under review, include these as systems required for safe shutdown. Designate these new systems with the same safe May Spuriously Operate shutdown path as the primary safe shutdown system under review (Refer to Figure 3-1).

and Affect System Operation ARolicabili Comments Applicable Alignment Statement Aligns with Intent Alignment Basis Engineering analysis EA10-036, Attachment 14, Section 5.2:

"The validation activity for SSEL components will be performed through a review of flow paths for systems and system boundaries. Components in the flow paths that require operation/repositioning to allow the system to function, and components that could spuriously operate and impair safe shutdown shall be identified/verified and included in the SSEL. Support system (e.g., electrical power and control, instrumentation, instrument air, cooling and ventilation, etc.) components shall also be included in the SSEL.

Components from the SSEL that are validated and determined necessary to support the nuclear safety objectives will be designated as safe shutdown equipment."

The review of the safe shutdown paths and safe shutdown system flowpaths, inclusive of equipment that may spuriously operate and affect system operation, is documented in of engineering analysis EA10-036. In addition, the FCS NFPA 805 safe shutdown model is contained in a relational database which maintains the following relationships: Performance Goal (Shutdown Path)-to-System; System-to-Equipment; Equipment-to-System; Equipment-to-Equipment; Equipment-to-Cable; Equipment-to-Fire Area; Cable-to-Fire Area. Consequently, there is no direct association maintained between a component and the Shutdown Path/Paths that the component ultimately supports.

This relationship is implicit through the logical relationships that are maintained in the database. These relationships are also documented in tables as Attachments 3, 4, 6, and 7 to engineering analysis EA10-036 and Attachments 4, 5, 6, and 7 to engineering analysis EA10-037. The relationships between Performance Goal (Shutdown Path)-to-System and System-to-Equipment are also identified in logic diagrams as Attachment 5 to engineering analysis EA10-036.

Multiple safe shutdown paths typically credit different combinations of redundant safe shutdown systems, with the result that most systems are assigned to more than one safe shutdown path. Therefore, safe shutdown paths are not designated for each system and component. Otherwise, the plant documentation is in alignment with the intent of the NEI 00-01 guidance.

Page B-57

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.1 Nuclear Safety Capability System and Equipment Selection Reference Document Doc, Details FCS Engineering Analysis EA10-036 Attachments 1, 3, 4, 5, 6, and 7 Attachment 14, Section 5.2 FCS Engineering Analysis EA10-037 Attachments 4, 5, 6, and 7 Page B-58

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.1 Nuclear Safety Capability System and Equipment Selection NEI 00-01 Section 3.0 Guidance 3.2.2.3 Develop a List of Safe Prepare a table listing the equipment identified for each system and the shutdown path that it supports. Identify any valves or other Shutdown Equipment and equipment that could spuriously operate and impact the operation of that safe shutdown system.

Assign the corresponding System and Safe Assign the safe shutdown path for the affected system to this equipment. During the cable selection phase, identify additional Shutdown Path(s) equipment required to support the safe shutdown function of the path (e.g., electrical distribution system equipment). Include this Designation to Each additional equipment in the safe shutdown equipment list. Attachment 3 to this document provides an example of a (SSEL). The SSEL identifies the list of equipment within the plant considered for safe shutdown and it documents various equipment-related attributes used in the analysis.

AD~licabili Applicable Alignment Statement Aligns with Intent Alianment Basis to engineering analysis EA10-036 contains the Safe Shutdown Equipment List (SSEL). The SSEL contains all components that support safe shutdown, or those components which may spuriously operate and impair safe shutdown.

Engineering analysis EA10-036, Attachment 14, Section 5.3.5:

"Electrical Properties: The normal power supply/source (and alternate power supply if one exists) associated with the safe shutdown component (including control power and indication only power, if applicable) shall be identified ..... and recorded". This is based on guidance from engineering analysis EA10-037, Attachment 8 (the procedure for post fire safe shutdown cable identification).

Engineering analysis EA10-037: , Section 5.3:

"Support components that are identified as necessary to support the function of SSD equipment being cable selected should be included in the Safe Shutdown Equipment List (SSEL), and associated with the SSD equipment being cable selected through SAFE component-to-component logic, system-to-component logic, or should otherwise be embedded within the cable selection for the SSD equipment being cable selected." , Appendix A, Section 3.5.3:

"Control Signals - The spurious cable selection should address any combination of the failure modes noted in this appendix. Included in this analysis are those cables that could negatively affect contact(s) in the control circuit being analyzed. This analysis may also result in the addition of supporting equipment logics, at which point the process of cable selection should continue by analyzing any newly identified components."

Page B-59

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.1 Nuclear Safety Capability System and Equipment Selection The circuit analysis and cable selection processes may identify additional supporting equipment (e.g., power supplies, instruments providing interlocks and/or permissives, etc.),

which are then added to the SSEL and subject to circuit analysis and cable selection. This process is performed iteratively until all safe shutdown support components and systems have been identified; in this manner, all of the electrical power supplies are typically verified, from low voltage AC and DC distribution up to the switchyard and emergency diesel generators. Review of Attachment 2 to engineering analysis EA10-036 shows that electrical distribution system components are included as safe shutdown components.

The review of the safe shutdown paths and safe shutdown system flowpaths, inclusive of equipment that may spuriously operate and affect system operation, is documented in of engineering analysis EA10-036. In addition, the FCS NFPA 805 safe shutdown model is contained in a relational database which maintains the following relationships: Performance Goal (Shutdown Path)-to-System; System-to-Equipment; Equipment-to-System; Equipment-to-Equipment; Equipment-to-Cable; Equipment-to-Fire Area; Cable-to-Fire Area. Consequently, there is not direct association maintained between a component and the Shutdown Path/Paths that the component ultimately supports.

This relationship is implicit through the logical relationships that are maintained in the database. These relationships are also documented in tables as Attachments 3, 4, 6, and 7 to engineering analysis EA10-036 and Attachments 4, 5, 6, and 7 to engineering analysis EA10-037. The relationships between Performance Goal (Shutdown Path)-to-System and System-to-Equipment are also identified in logic diagrams as Attachment 5 to engineering analysis EA10-036.

Multiple safe shutdown paths typically credit different combinations of redundant safe shutdown systems, with the result that most systems are assigned to more than one safe shutdown path. Therefore, safe shutdown paths are not designated for each system and component. Otherwise, the plant documentation is in alignment with the intent of the NEI 00-01 guidance.

Comments Reference Document Doc. Details FCS Engineering Analysis EA10-036 Attachments 1, 2, 3,4,5,6, and 7 Attachment 14, Section 5.3.5 FCS Engineering Analysis EA10-037 Attachments 4, 5, 6, and 7 Attachment 8, Section 5.3 and Appendix A, Section 3.5.3 Page B-60

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.1 Nuclear Safety Capability System and Equipment Selection NEI 00-01 Section 3.0 Guidance 3.2.2.4 Identify Equipment Collect additional equipment-related information necessary for performing the post-fire safe shutdown analysis for the equipment. In Information Required for order to facilitate the analysis, tabulate this data for each piece of equipment on the SSEL. Refer to Attachment 3 to this document for the Safe Shutdown an example of a SSEL. Examples of related equipment data should include the equipment type, equipment description, safe shutdown Analysis system, safe shutdown path, drawing reference, fire area, fire zone, and room location of equipment. Other information such as the following may be useful in performing the safe shutdown analysis: normal position, hot shutdown position, cold shutdown position, failed air position, failed electrical position, high/low pressure interface concern, and spurious operation concern.

AD&licabili Applicable Alignment Statement Aligns Alignment Basis Engineering analysis EA10-036, Attachment 14, Section 5.3 lists the information that is captured for each component on the SSEL. The SSEL in Attachment 2 of engineering analysis EA10-036 contains the following fields for each component:

-Equipment ID (Designation)

-Equipment Description

-System ID

-Fire Area (Fire Zone) Location

-High/Low Pressure Interface

-Normal Position

-Required Position - Hot

-Required Position - Cold

-Failed Position (Loss of Power)

-Failed Position (Loss of Air)

-Required Support Equipment - Power Supplies, Etc.

-Notes

-Primary References Comments Reference Document Doc. Details FCS Engineering Analysis EA10-036 Attachment 2 Attachment 14, Section 5.3 Page B-61

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.1 Nuclear Safety Capability System and Equipment Selection NEI 00-01 Rf NEI 00-01 Section 3.0 Guidance 3.2.2.5 Identify Dependencies In the process of defining equipment and cables for safe shutdown, identify additional supporting equipment such as electrical power Between Equipment, and interlocked equipment. As an aid in assessing identified impacts to safe shutdown, consider modeling the dependency between Supporting Equipment, equipment within each safe shutdown path either in a relational database or in the form of a Safe Shutdown Logic Diagram (SSLD).

Safe Shutdown Systems Attachment 4 provides an example of a SSLD that may be developed to document these relationships.

and Safe Shutdown Paths ADplicabilitv Comments Applicable Alignment Statement Aligns Alionment Basis* to engineering analysis EA10-036 contains the Safe Shutdown Equipment List (SSEL). The SSEL contains all components that support safe shutdown, or those components which may spuriously operate and impair safe shutdown.

The circuit analysis and cable selection processes, described in Attachment 8 of engineering analysis EA10-037, may identify additional supporting equipment (e.g., power supplies, instruments providing interlocks and/or permissives, etc.), which are then added to the SSEL and subject to circuit analysis and cable selection. This process is performed iteratively until all safe shutdown support components and systems have been identified; in this manner, all of the electrical power supplies are typically verified, from low voltage AC and DC distribution up to the switchyard and emergency diesel generators. Review of Attachment 2 to engineering analysis EA10-036 shows that electrical distribution system components are included as safe shutdown components.

The review of the safe shutdown paths and safe shutdown system flowpaths, inclusive of equipment that may spuriously operate and affect system operation, is documented in of engineering analysis EA10-036. In addition, the FCS NFPA 805 safe shutdown model is contained in a relational database which maintains the following relationships: Performance Goal (Shutdown Path)-to-System; System-to-Equipment; Equipment-to-System; Equipment-to-Equipment; Equipment-to-Cable; Equipment-to-Fire Area; Cable-to-Fire Area. Consequently, there is not direct association maintained between a component and the Shutdown Path/Paths that the component ultimately supports.

This relationship is implicit through the logical relationships that are maintained in the database. These relationships are also documented in tables as Attachments 3, 4, 6, and 7 to engineering analysis EA10-036 and Attachments 4, 5, 6, and 7 to engineering analysis EA10-037. The relationships between Performance Goal (Shutdown Path)-to-System and System-to-Equipment are also identified in logic diagrams as Attachment 5 to engineering analysis EA10-036.

The plant methodology is in alignment with NEI 00-01 guidance.

Comments Page B-62

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.1 Nuclear Safety Capability System and Equipment Selection Reference Document Doc. Details FCS Engineering Analysis EA10-036 Attachments 1, 2, 3, 4, 5, 6, and 7 FCS Engineering Analysis EA10-037 Attachments 4, 5, 6, 7, and 8 Page B-63

Omaha Public Power District FCS NFPA 805 TransitionReport Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.2 Nuclear Safety Capability Circuit Analysis 2.4.2.2.1 Circuits Required in Nuclear Safety Functions. Circuits required for the nuclear safety functions shall be identified. This includes circuits that are required for operation, that could prevent the operation, or that result in the maloperation of the equipment identified in 2.4.2.1. This evaluation shall consider fire-induced failure modes such as hot shorts (external and internal), open circuits, and shorts to ground, to identify circuits that are required to support the proper operation of components required to achieve the nuclear safety performance criteria, including spurious operation and signals. This will ensure that a comprehensive population of circuitry is evaluated.

2.4.2.2.2 Other Required Circuits. Other circuits that share common power supply and/or common enclosure with circuits required to achieve nuclear safety performance criteria shall be evaluated for their impact on the ability to achieve nuclear safety performance criteria.

(a) Common Power Supply Circuits. Those circuits whose fire-induced failure could cause the loss of a power supply required to achieve the nuclear safety performance criteria shall be identified. This situation could occur if the upstream protection device (i.e., breaker or fuse) is not properly coordinated with the downstream protection device.

(b) Common Enclosure Circuits. Those circuits that share enclosures with circuits required to achieve the nuclear safety performance criteria and whose fire-induced failure could cause the loss of the required components shall be identified. The concern is that the effects of a fire can extend outside of the immediate fire area due to fire-induced electrical faults on inadequately protected cables or via inadequately sealed fire area boundaries.

NEI 00-01 Ref NEI 00-01 Section 3.0 Guidance 3.3 Safe Shutdown Cable This section provides industry guidance on the recommended methodology and criteria for selecting safe shutdown cables and Selection and Location determining their potential impact on equipment required for achieving and maintaining safe shutdown of an operating nuclear power plant for the condition of an exposure fire. The Appendix R safe shutdown cable selection criteria are developed to ensure that all cables that could affect the proper operation or that could cause the maloperation of safe shutdown equipment are identified and that these cables are properly related to the safe shutdown equipment whose functionality they could affect. Through this cable-to-equipment relationship, cables become part of the safe shutdown path assigned to the equipment affected by the cable.

Aoolicabilit Comments Applicable Alignment Statement Not Required Alicnment Basis Generic paragraph. Detailed alignment discussed in subsequent reference paragraphs.

Comments Reference Document Doc. Details Page B-64

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.2 Nuclear Safety Capability Circuit Analysis NEI 00-01 Ref NEI 00-01 Section 3.0 Guidance 3.3.1 Criteria/Assumptions To identify an impact to safe shutdown equipment based on cable routing, the equipment must have cables that affect it identified.

Carefully consider how cables are related to safe shutdown equipment so that impacts from these cables can be properly assessed in terms of their ultimate impact on safe shutdown system equipment.

Consider the following criteria when selecting cables that impact safe shutdown equipment:

Apolicability Comments Applicable Alignment Statement Not Required Alignment Basis Generic paragraph. Detailed alignment discussed in subsequent reference paragraphs.

Comments Reference Document Doc. Details Page B-65

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.2 Nuclear Safety Capability Circuit Analysis NEI 00-01 Ref NEI 00-01 Section 3.0 Guidance 3.3.1.1 Criteria/Assumptions The list of cables whose failure could impact the operation of a piece of safe shutdown equipment includes more than those cables connected to the equipment. The relationship between cable and affected equipment is based on a review of the electrical or elementary wiring diagrams. To assure that all cables that could affect the operation of the safe shutdown equipment are identified, investigate the power, control, instrumentation, interlock, and equipment status indication cables related to the equipment. Consider reviewing additional schematic diagrams to identify additional cables for interlocked circuits that also need to be considered for their impact on the ability of the equipment to operate as required in support of postfire safe shutdown. As an option, consider applying the screening criteria from Section 3.5 as a part of this section. For an example of this see Section 3.3.1.4.

ADplicabilit Comments Applicable Alignment Statement Aligns Alianment Basis The circuit analysis and cable selection data that comprises the NFPA 805 at-power safe shutdown model, the Fire PRA, and the NFPA 805 non-power operations model is obtained from two source documents: (1) FCS engineering analysis EA-FC-97-044, which contains the legacy circuit analysis and cable selection data associated with the FCS 10 CFR 50 Appendix R Analysis, and (2) FCS engineering analysis EA10-037, which contains the circuit analysis and cable selection methodology and data for components added to the FCS NFPA 805 at-power safe shutdown model, the Fire PRA, and the NFPA 805 non-power operations model.

The legacy 10 CFR 50 Appendix R circuit analysis and cable selection methodology and data from EA-FC-97-044 was reviewed by FCS as part of the FCS NFPA 805 Transition Project to determine its applicability for use in the NFPA 805 at-power safe shutdown model, the Fire PRA, and the NFPA 805 non-power operations model. The circuit analysis and cable selection methodology described in EA-FC-97-044 was determined by FCS to be generally consistent with the assumptions/criteria of NEI 00-01. However, a number of discrepancies were identified by FCS in the legacy circuit analysis and cable selection data of EA-FC-97-044. These discrepancies were documented in FCS Condition Reports (see below), and were subsequently corrected and incorporated into EA10-037.

" CR2009-2711 (cables added to address random missing cables, and cables added to address the failure mode of multiple DC grounds)

" CR2009-4850 (cables added to address common power supply failure mode for 120V AC branch circuits lacking isolation between loads fed from common branch circuit)

" CR2009-4851 (cables added to address common power supply failure mode for 120V AC branch circuits lacking isolation between loads fed from common branch circuit)

" CR2009-4852 (cables added to address common power supply failure mode for 120V AC branch circuits lacking isolation between loads fed from common branch circuit)

" CR2009-4763 (cables added to address random missing cables)

" CR2009-4826 (miscellaneous corrections to safe shutdown cable IDs)

" CR2010-2173 (cables added to address the failure mode for non-robustly shielded instrumentation cables)

" CR2010-2202 (miscellaneous corrections to safe shutdown cable fire area locations)

" CR2010-2206 (cables added to address random missing cables, miscellaneous corrections to safe shutdown cable fire area locations)

" CR2010-3383 (cables added to address random missing cables)

" CR2010-6640 (miscellaneous corrections to safe shutdown cable fire area locations)

" CR2011-0244 (cables added to address random missing cables, and cables added to address instrument loop isolation)

Page B-66

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.2 Nuclear Safety Capability Circuit Analysis

" CR2011-0770 (cables added to address random missing cables, and cables added to address failure mode of multiple DC grounds)

" CR2011-0733 (miscellaneous corrections to safe shutdown cable fire locations)

" CR2011-0759 (miscellaneous corrections to safe shutdown cable fire area locations)

" CR2011-0964 (cables added to address random missing cables, and cables added to address failure mode of multiple DC grounds)

" CR2011-1007 (miscellaneous corrections to safe shutdown cable fire area locations)

The circuit analysis and cable selection methodology utilized by FCS for EA1 0-037 is based directly on the assumptions/criteria of NEI 00-01, Sections 3.3 and 3.5.

The deterministic safe shutdown analysis methodology utilized by FCS for EA10-036 is based directly on the assumptions/criteria of NEI 00-01, Sections 3.1, 3.2, 3.4, and 3.5.

Engineering analysis EA-FC-97-044, Section 5 and Attachment 2:

This NEI 00-01 criteria is explicitly identified in EA-FC-97-044 (Section 5). Review of the component cable selection data sheets in the body of the analysis (Attachment 2) provides objective evidence that this criteria is met with some exceptions, which have been documented and subsequently corrected through the FCS Condition Reports identified above.

Engineering analysis EA10-037, Attachment 8, Section 5 and Appendix A; and engineering analysis EA10-037, Attachment 4:

This NEI 00-01 criteria is explicitly identified in Attachment 8 of EA10-037 (Section 5 and Appendix A). Review of the component cable selection data sheets in the body of the analysis (Attachment 4) provides objective evidence that this criteria is met.

Comments Note that FCS engineering analysis EA-FC-97-044 and FCS engineering analysis EA10-037 will be combined into a single analysis following the transition to a NFPA 805 licensing basis.

Reference Document Doc. Details FCS Engineering Analysis EA-FC-97-044 Section 5 Attachment 2 FCS Engineering Analysis EA10-037 Attachment 8, Section 5 and Appendix A Attachment 4 Page B-67

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.2 Nuclear Safety Capability Circuit Analysis NEI 00-01 Rer NEI 00-01 Section 3.0 Guidance 3.3.1.2 Criteria/Assumptions In cases where the failure (including spurious actuations) of a single cable could impact more than one piece of safe shutdown equipment, include the cable with each piece of safe shutdown equipment.

Applicabilitv Comments Applicable Alignment Statement Aligns AUgnmenBais Engineering analysis EA-FC-97-044, Section 5 and Attachment 2:

This NEI 00-01 criteria is not explicitly identified anywhere in EA-FC-97-044; however, review of the component cable selection data sheets in the body of the analysis (Attachment 2) does provide objective evidence that this criteria is met. The same cable ID is mapped to more than one safe shutdown component.

Engineering analysis EA1 0-037, Attachment 8, Section 5 and Appendix A; and engineering analysis EA1 0-037, Attachment 4:

This NEI 00-01 criteria is explicitly identified in Attachment 8 of EA10-037 (Section 5 and Appendix A). Review of the component cable selection data sheets in the body of the analysis (Attachment 4) provides objective evidence that this criteria is met. The same cable ID is mapped to more than one safe shutdown component.

Reference Document Doc. Details FCS Engineering Analysis EA-FC-97-044 Section 5 Attachment 2 FCS Engineering Analysis EA10-037 Attachment 8, Section 5 and Appendix A Attachment 4 Page B-68

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.2 Nuclear Safety Capability Circuit Analysis NEI 00-01 Section 3.0 Guidance 3.3.1.3 Criteria/Assumptions Electrical devices such as relays, switches and signal resistor units are considered to be acceptable isolation devices. In the case of instrument loops, review the isolation capabilities of the devices in the loop to determine that an acceptable isolation device has been installed at each point where the loop must be isolated so that a fault would not impact the performance of the safe shutdown instrument function.

A1olicabiliY Applicable Aligns Alignment Basis Engineering analysis EA-FC-97-044, Assumption 4.1, Section 5, and Attachment 2:

This NEI 00-01 criteria is explicitly identified in EA-FC-97-044 for motive and control power circuits (Section 5). Review of the component cable selection data sheets in the body of the analysis (Attachment 2) provides objective evidence that this criteria has been met with some exceptions, as documented and corrected in FCS Condition Reports (see Table B-2, Section 3.3.1.1).

This NEI 00-01 criteria is not explicitly identified anywhere in EA-FC-97-044 for instrumentation loops. Review of the component cable selection data sheets in the body of the analysis (Attachment 2) provides objective evidence that this criteria has been met with some exceptions, as documented and corrected in FCS Condition Reports (see Table B-2, Section 3.3.1.1).

Engineering analysis EA10-037, Attachment 8, Section 5 and Appendix A; and engineering analysis EA10-037, Attachment 4:

This NEI 00-01 criteria is explicitly identified in Attachment 8 of EA10-037 (Section 5 and Appendix A). Review of the component cable selection data sheets in the body of the analysis (Attachment 4) provides objective evidence that this criteria is met.

Comments Reference Document Doc. Details FCS Engineering Analysis EA-FC-97-044 Assumption 4.1 Section 5 Attachment 2 FCS Engineering Analysis EA1O-037 Attachment 8, Section 5 and Appendix A Attachment 4 Page B-69

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.2 Nuclear Safety Capability Circuit Analysis NEI 00-01 Section 3.0 Guidance 3.3.1.4 Criteria/Assumptions Screen out cables for circuits that do not impact the safe shutdown function of a component (i.e., annunciator circuits, space heater circuits and computer input circuits) unless some reliance on these circuits is necessary. However, they must be isolated from the component's control scheme in such a way that a cable fault would not impact the performance of the circuit.

AnU)licabili Applicable Alignment Statement Aligns Alianment Basis Engineering analysis EA-FC-97-044, Section 5 and Attachment 2:

This NEI 00-01 criteria is explicitly identified in EA-FC-97-044 (Section 5). Review of the component cable selection data sheets in the body of the analysis (Attachment 2) provides objective evidence that this criteria has been met with some exceptions, as documented and corrected in FCS Condition Reports (see Table B-2, Section 3.3.1.1).

Cables associated with the scheme number for a given safe shutdown component, and which cannot impact the safe shutdown function of the given safe shutdown component are typically identified as being not required on the associated component cable selection data sheets in the body of the analysis.

Engineering analysis EA10-037, Attachment 8, Section 5 and Appendix A; and engineering analysis EA10-037, Attachment 4:

This NEI 00-01 criteria is explicitly identified in Attachment 8 of EA10-037 (Section 5 and Appendix A). Review of the component cable selection data sheets in the body of the analysis (Attachment 4) provides objective evidence that this criteria is met. Cables associated with the scheme number for a given safe shutdown component, and which cannot impact the safe shutdown function of the given safe shutdown component are typically identified as being not required on the associated component cable selection data sheets in the body of the analysis.

Reference Document Doc. Details FCS Engineering Analysis EA-FC-97-044 Section 5 Attachment 2 FCS Engineering Analysis EA10-037 Attachment 8, Section 5 and Appendix A Attachment 4 Page B-70

Omaha Public PowerDistrict FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.2 Nuclear Safety Capability Circuit Analysis NEI 00-01 Rer NEI 00-01 Section 3.0 Guidance 3.3.1.5 Criteria/Assumptions For each circuit requiring power to perform its safe shutdown function, identify the cable supplying power to each safe shutdown and/or required interlock component. Initially, identify only the power cables from the immediate upstream power source for these interlocked circuits and components (i.e., the closest power supply, load center or motor control center). Review further the electrical distribution system to capture the remaining equipment from the electrical power distribution system necessary to support delivery of power from either the offsite power source or the emergency diesel generators (i.e., onsite power source) to the safe shutdown equipment. Add this equipment to the safe shutdown equipment list. Evaluate the power cables for this additional equipment for associated circuits concerns.

ApDlicabilitv Comments Applicable Alignment Statement Aligns Alignment Basis Engineering analysis EA-FC-97-044, Section 5 and Attachment 2:

This NEI 00-01 criteria is explicitly identified in EA-FC-97-044 for identification and association of power cables to safe shutdown equipment (Section 5). Review of the component cable selection data sheets in the body of the analysis (Attachment 2) provides objective evidence that this criteria has been met with some exceptions, as documented and corrected in FCS Condition Reports (see Table B-2, Section 3.3.1.1). The iterative process of identifying additional support components (i.e., power supplies, etc.) through the cable selection process as described in NEI 00-01 is not described in the FCS analysis. The development of the NFPA 805 safe shutdown model for FCS included steps to review for the completeness of the components selected for the electrical distribution system, and other supporting systems/functions. This review is documented in engineering analysis EA10-036.

Engineering analysis EA10-037, Attachment 8, Section 5 and Appendix A; and engineering analysis EA10-037, Attachment 4:

This NEI 00-01 criteria is explicitly identified in Attachment 8 of EA10-037 (Section 5 and Appendix A). Review of the component cable selection data sheets in the body of the analysis (Attachment 4) provides objective evidence that this criteria is met. The iterative process of identifying additional support components (i.e., power supplies, etc.) through the cable selection process as described in NEI 00-01 is described in the FCS analysis.

Page B-71

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.2 Nuclear Safety Capability Circuit Analysis Reference Document Doc. Details FCS Engineering Analysis EA-FC-97-044 Section 5 Attachment 2 FCS Engineering Analysis EA10-037 Attachment 8, Section 5 and Appendix A Attachment 4 Page B-72

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.2 Nuclear Safety Capability Circuit Analysis NEI 00-01 Ref NEI 00-01 Section 3.0 Guidance 3.3.1.6 Criteria/Assumptions The automatic initiation logics for the credited post-fire safe shutdown systems are not required to support safe shutdown. Each system can be controlled manually by operator actuation in the main control room or emergency control station. If operator actions outside the MCR are necessary, those actions must conform to the regulatory requirements on manual actions. However, ifnot protected from the effects of fire, the fire-induced failure of automatic initiation logic circuits must not adversely affect any post-fire safe shutdown system function.

Applicable Alianment Statement Aligns Alignment Basis Engineering analysis EA-FC-97-044, Section 5 and Attachment 2:

This NEI 00-01 criteria is explicitly identified in EA-FC-97-044 (Section 5). Review of the component cable selection data sheets in the body of the analysis (Attachment 2) provides objective evidence that this criteria has been met.

Engineering analysis EA10-037, Attachment 8, Section 5 and Appendix A; and engineering analysis EA10-037, Attachment 4:

This NEI 00-01 criteria is explicitly identified in Attachment 8 of EA10-037 (Section 5 and Appendix A). Review of the component cable selection data sheets in the body of the analysis (Attachment 4) provides objective evidence that this criteria is met.

Comments Reference Document Doc, Details FCS Engineering Analysis EA-FC-97-044 Section 5 Attachment 2 FCS Engineering Analysis EA10-037 Attachment 8, Section 5 and Appendix A Attachment 4 Page B-73

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.2 Nuclear Safety Capability Circuit Analysis NEI 00-01 Ref NEI 00-01 Section 3.0 Guidance 3.3.1.7 Criteria/Assumptions Cabling for the electrical distribution system is a concern for those breakers that feed associated circuits and are not fully coordinated with upstream breakers. With respect to electrical distribution cabling, two types of cable associations exist. For safe shutdown considerations, the direct power feed to a primary safe shutdown component is associated with the primary component. For example, the power feed to a pump is necessary to support the pump. Similarly, the power feed from the load center to an MCC supports the MCC. However, for cases where sufficient branch-circuit coordination is not provided, the same cables discussed above would also support the power supply. For example, the power feed to the pump discussed above would support the bus from which it is fed because, for the case of a common power source analysis, the concern is the loss of the upstream power source and not the connected load. Similarly, the cable feeding the MCC from the load center would also be necessary to support the load center.

A iaklic y Applicable Alignment Statement Aligns Alignment Basis Engineering analysis EA10-036, Attachment 11: 1 of EA10-036 provides a summary of the review of FCS electrical design calculations which address breaker/fuse coordination. These FCS calculations demonstrate breaker/fuse coordination is maintained for the electrical distribution systems and system alignments that are analyzed in the FCS NFPA 805 at-power safe shutdown model, the Fire PRA, and the NFPA 805 non-power operations model.

Engineering analysis EA-FC-97-044, Section 5 and Attachment 2:

This NEI 00-01 criteria is explicitly identified in EA-FC-97-044 (Section 5). Review of the component cable selection data sheets in the body of the analysis (Attachment 2) provides objective evidence that this criteria is met.

Engineering analysis EA10-037, Attachment 8, Section 5 and Appendix A; and engineering analysis EA10-037, Attachment 4:

This NEI 00-01 criteria is explicitly identified in Attachment 8 of EA10-037 (Section 5 and Appendix A). Review of the component cable selection data sheets in the body of the analysis (Attachment 4) provides objective evidence that this criteria is met.

Comments Page B-74

Omaha Public PowerDistrict FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.2 Nuclear Safety Capability Circuit Analysis Reference Document Doc, Details FCS Engineering Analysis EA10-036 Attachment 11 FCS Engineering Analysis EA-FC-97-044 Section 5 Attachment 2 FCS Engineering Analysis EA10-037 Attachment 8, Section 5 and Appendix A Attachment 4 Page B-75

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.2 Nuclear Safety Capability Circuit Analysis NEI 00-01 Rf NEI 00-01 Section 3.0 Guidance 3.3.2 Associated Circuit Cables Associated Circuit Cables Appendix R, Section III.G.2, requires that separation features be provided for equipment and cables, including associated nonsafety circuits that could prevent operation or cause maloperation due to hot shorts, open circuits, or shorts to ground, of redundant trains of systems necessary to achieve hot shutdown. The three types of associated circuits were identified in Reference 6.1.5 and further clarified in a NRC memorandum dated March 22, 1982 from R. Mattson to D. Eisenhut, Reference 6.1.6.

They are as follows:

- Spurious actuations

- Common power source

- Common enclosure Cables Whose Failure May Cause Spurious Actuations Safe shutdown system spurious actuation concerns can result from fire damage to a cable whose failure could cause the spurious actuation/mal-operation of equipment whose operation could affect safe shutdown. These cables are identified in Section 3.3.3 together with the remaining safe shutdown cables required to support control and operation of the equipment.

Common Power Source Cables The concern for the common power source associated circuits is the loss of a safe shutdown power source due to inadequate breaker/fuse coordination. In the case of a fire-induced cable failure on a non-safe shutdown load circuit supplied from the safe shutdown power source, a lack of coordination between the upstream supply breaker/fuse feeding the safe shutdown power source and the load breaker/fuse supplying the non-safe shutdown faulted circuit can result in loss of the safe shutdown bus. This would result in the loss of power to the safe shutdown equipment supplied from that power source preventing the safe shutdown equipment from performing its required safe shutdown function. Identify these cables together with the remaining safe shutdown cables required to support control and operation of the equipment. Refer to Section 3.5.2.4 for an acceptable methodology for analyzing the impact of these cables on post-fire safe shutdown.

Common Enclosure Cables The concern with common enclosure associated circuits is fire damage to a cable whose failure could propagate to other safe shutdown cables in the same enclosure either because the circuit is not properly protected by an isolation device (breaker/fuse) such that a fire-induced fault could result in ignition along its length, or by the fire propagating along the cable and into an adjacent fire area.

This fire spread to an adjacent fire area could impact safe shutdown equipment in that fire area, thereby resulting in a condition that exceeds the criteria and assumptions of this methodology (i.e., multiple fires). Refer to Section 3.5.2.5 for an acceptable methodology for analyzing the impact of these cables on post-fire safe shutdown.

Applicabilitv Comments Applicable Alignment Statement Aligns Page B-76

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.2 Nuclear Safety Capability Circuit Analysis Alignment Basis Engineering analysis EA10-036, Attachment 11: 1 of EA10-036 addresses associated circuit concerns, inclusive of common power supply failures, common enclosure failures, current transformer failures due to open circuited secondary windings, high impedance faults - multiple high impedance faults, and high-pressure/low-pressure interface degradation. 1 of EA10-036 also provides a summary of the associated circuits concern regarding to spurious operation and high-pressure/low-pressure interface degradation.

Cables whose failure may cause spurious actuations, inclusive of high/low pressure interfaces, are identified through the circuit analysis and cable selection processes as described below:

Engineering analysis EA-FC-97-044, Assumption 4.3, Section 5, and Attachment 2:

This NEI 00-01 criteria is explicitly identified in EA-FC-97-044 (Assumption 4.3, Section 5). Review of the component cable selection data sheets in the body of the analysis (Attachment 2) provides objective evidence that this criteria has been met with some exceptions, as documented and corrected in FCS Condition Reports (see Table B-2, Section 3.3.1.1).

Although Assumption 4.3 of EA-FC-97-044 states the following: "Fire induced multiple simultaneous cable faults are not assumed to occur, except for high/low pressure interface components.", a review of the component cable selection data sheets in the body of the analysis was performed by FCS as part of the NFPA 805 Transition Project, and the review did not identify any safe shutdown component for which this assumption resulted in FCS not selecting a required safe shutdown cable. This assumption is not used in the circuit analysis and cable selection performed for the FCS NFPA 805 at-power safe shutdown model, the Fire PRA, and the NFPA 805 non-power operations model in engineering analysis EA10-037, and is not used in the NFPA 805 at-power safe shutdown analysis in engineering analysis EA10-036.

Engineering analysis EA10-037, Attachment 8, Section 5 and Appendix A; and engineering analysis EA10-037, Attachment 4:

This NEI 00-01 criteria is explicitly identified in Attachment 8 of EA10-037 (Section 5 and Appendix A). Review of the component cable selection data sheets in the body of the analysis (Attachment 4) provides objective evidence that this criteria is met.

Comments Reference Document Doc, Details FCS Engineering Analysis EA10-036 Attachment 11 FCS Engineering Analysis EA-FC-97-044 Assumption 4.3 Section 5 Attachment 2 FCS Engineering Analysis EA10-037 Attachment 8, Section 5 and Appendix A Attachment 4 Page B-77

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.2 Nuclear Safety Capability Circuit Analysis NEI 00-01 Ref NEI 00-01 Section 3.0 Guidance 3.3.3 Methodology for Cable Refer to Figure 3-4 for a flowchart illustrating the various steps involved in selecting the cables necessary for performing a post-fire Selection and Location safe shutdown analysis. Use the following methodology to define the cables required for safe shutdown including cables that may cause associated circuits concerns for a post-fire safe shutdown analysis:

ARnlicabili Comments Applicable Alignment Statement Not Required Alignment Basis Generic paragraph. Detailed alignment discussed in subsequent reference paragraphs.

Comments Reference Document Doc. Details Page B-78

Omaha Public PowerDistrict FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.2 Nuclear Safety Capability Circuit Analysis NEI 00-01 Ref NEI 00-01 Section 3.0 Guidance 3.3.3.1 Identify Circuits Required For each piece of safe shutdown equipment defined in section 3.2, review the appropriate electrical diagrams including the following for the Operation of the documentation to identify the circuits (power, control, instrumentation) required for operation or whose failure may impact the operation Safe Shutdown Equipment of each piece of equipment:

- Single-line electrical diagrams

- Elementary wiring diagrams

- Electrical connection diagrams

- Instrument loop diagrams.

For electrical power distribution equipment such as power supplies, identify any circuits whose failure may cause a coordination concern for the bus under evaluation.

If power is required for the equipment, include the closest upstream power distribution source on the safe shutdown equipment list.

Through the iterative process described in Figures 3-2 and 3-3, include the additional upstream power sources up to either the offsite or the emergency power source.

Aoolicabilitv Comments Applicable Alignment Statement Aligns Alignment Basis Engineering analysis EA10-036, Attachment 11: 1 of EA10-036 provides a summary of the review of FCS electrical design calculations which address breaker/fuse coordination. These FCS calculations demonstrate breaker/fuse coordination is maintained for the electrical distribution systems and system alignments that are analyzed in the FCS NFPA 805 at-power safe shutdown model, the Fire PRA, and the NFPA 805 non-power operations model.

Engineering analysis EA-FC-97-044, Section 5 and Attachment 2:

This NEI 00-01 criteria is explicitly identified in EA-FC-97-044 for identification and association of power, control and instrumentation cables to safe shutdown equipment (Sections 5.1.1 through 5.1.3). Review of the component cable selection data sheets in the body of the analysis (Attachment 2) provides objective evidence that this criteria has been met with some exceptions, as documented and corrected in FCS Condition Reports (see Table B-2, Section 3.3.1.1). The iterative process of identifying additional support components (i.e., power supplies, etc.) through the cable selection process as described in NEI 00-01 is not described in the FCS analysis. The development of the NFPA 805 safe shutdown model for FCS included steps to review for the completeness of the components selected for the electrical distribution system, and other supporting systems/functions. This review is documented in engineering analysis EA10-036.

Page B-79

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.2 Nuclear Safety Capability Circuit Analysis Engineering analysis EA10-037, Attachment 8, Section 5 and Appendix A; and engineering analysis EA10-037, Attachment 4:

This NEI 00-01 criteria is explicitly identified in Attachment 8 of EA10-037 (Section 5 and Appendix A). Review of the component cable selection data sheets in the body of the analysis (Attachment 4) provides objective evidence that this criteria is met. The iterative process of identifying additional support components (i.e., power supplies, etc.) through the cable selection process as described in NEI 00-01 is described in the FCS analysis.

Comments Reference Document Doc. Details FCS Engineering Analysis EA10-036 Attachment 11 FCS Engineering Analysis EA-FC-97-044 Section 5 Attachment 2 FCS Engineering Analysis EA10-037 Attachment 8, Section 5 and Appendix A Attachment 4 Page B-80

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.2 Nuclear Safety Capability Circuit Analysis NEI 00-01 Section 3.0 Guidance 3.3.3.2 Identify Interlocked Circuits In reviewing each control circuit, investigate interlocks that may lead to additional circuit schemes, cables and equipment. Assign to the and Cables Whose equipment any cables for interlocked circuits that can affect the equipment.

Spurious Operation or Mal-operation Could Affect While investigating the interlocked circuits, additional equipment or power sources may be discovered. Include these interlocked Shutdown equipment or power sources in the safe shutdown equipment list (refer to NEI-00-01 Rev 1 Figure 3-3) if they can impact the operation of the equipment under consideration.

ADlicabilit Comments Applicable Alignment Statement Aligns Alignment Basis Engineering analysis EA-FC-97-044, Section 5 and Attachment 2:

This NEI 00-01 criteria is explicitly identified in EA-FC-97-044 for identification interlocks (i.e., auxiliary contacts as input to control schemes) to safe shutdown equipment (Sections 5.1.1 and 5.1.2.5). Review of the component cable selection data sheets in the body of the analysis (Attachment 2) provides objective evidence that this criteria has been met with some exceptions, as documented and corrected in FCS Condition Reports (see Table B-2, Section 3.3.1.1). The iterative process of identifying additional support components (i.e., power supplies, etc.) through the cable selection process as described in NEI 00-01 is not described in the FCS analysis. The development of the NFPA 805 safe shutdown model for FCS included steps to review for the completeness of the components selected for the electrical distribution system, and other supporting systems/functions. This review is documented in engineering analysis EA10-036.

Engineering analysis EA10-037, Attachment 8, Section 5 and Appendix A; and engineering analysis EA10-037, Attachment 4:

This NEI 00-01 criteria is explicitly identified in Attachment 8 of EA10-037 (Section 5 and Appendix A). Review of the component cable selection data sheets in the body of the analysis (Attachment 4) provides objective evidence that this criteria is met. The iterative process of identifying additional support components (i.e., power supplies, etc.) through the cable selection process as described in NEI 00-01 is described in the FCS analysis.

Page B-81

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.2 Nuclear Safety Capability Circuit Analysis Reference Document Doc. Details FCS Engineering Analysis EA-FC-97-044 Section 5 Attachment 2 FCS Engineering Analysis EA10-037 Attachment 8, Section 5 and Appendix A Attachment 4 Page B-82

Omaha Public PowerDistrict FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.2 Nuclear Safety Capability Circuit Analysis NEI00-01 Rf NEI 00-01 Section 3.0 Guidance 3.3.3.3 Assign Cables to the Safe Given the criteria/assumptions defined in Section 3.3.1, identify the cables required to operate or that may result in maloperation of Shutdown Equipment each piece of safe shutdown equipment.

Tabulate the list of cables potentially affecting each piece of equipment in a relational database including the respective drawing numbers, their revision and any interlocks that are investigated to determine their impact on the operation of the equipment. In certain cases, the same cable may support multiple pieces of equipment. Relate the cables to each piece of equipment, but not necessarily to each supporting secondary component.

If adequate coordination does not exist for a particular circuit, relate the power cable to the power source. This will ensure that the power source is identified as affected equipment in the fire areas where the cable may be damaged.

ADplicabilit Comments Applicable Alignment Statement Aligns Allanment Basis Engineering analysis EA-FC-97-044, Section 5 and Attachment 2:

This NEI 00-01 criteria is explicitly identified in EA-FC-97-044 (Sections 5.1.1 through 5.1.3). The component cable selection data sheets in the body of the analysis (Attachment

2) provides objective evidence that this criteria has been met with some exceptions, as documented and corrected in FCS Condition Reports (see Table B-2, Section 3.3.1.1).

The information fields included on each component cable selection datasheet include the following:

Component Number "Component Type "Component Name "Component Power Supply "Normal Position "Desired Position "Failed Position (loss of power)

"Cable Number "Cable Type (typical - I, C, A, Power)

"Cable Fault Consequences (typical - LOP, LOC, SPUR, LOI, and NONE)

"Cable Required for Safe Shutdown Yes/No "Notes "Comments/Reference Drawings Page B-83

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.2 Nuclear Safety Capability Circuit Analysis Engineering analysis EA10-037, Attachment 8, Section 5 and Appendix A; and engineering analysis EA10-037, Attachment 4:

This NEI 00-01 criteria is explicitly identified in Attachment 8 of EA10-037 (Section 5 and Appendix A). Review of the component cable selection data sheets in the body of the analysis (Attachment 4) provides objective evidence that this criteria is met. The information fields included on each component cable selection datasheet include the following:

"Component ID "Component Description

" Fire Area Location "Motive Power Source ID "Control Power Source ID "Additional Power Sources "High-Low Pressure Interface Yes/No "Required for Hot Shutdown Active/Passive "Required for Cold Shutdown Active/Passive "Normal Position

Failed Air Position

" Failed Power Position

Hot Shutdown Position "Cold Shutdown Position "Fire PRA Position

NPO (Position)

"System ID "Cable Data

" Logic Classification

" Cable Required for Safe Shutdown Yes/No

" Cable Function (typical - Indication, Control, Power, LOC, SPO, LOI, etc.)

" Drawing Number

" Sheet Number

Revision Number

" Remarks/Comments Engineering analysis EA10-037, Attachment 6, provides a table of every cable required for the FCS NFPA 805 at-power safe shutdown model, the Fire PRA, and the NFPA 805 non-power operations model. This table includes the following:

" Equipment ID

Associated Cable ID

" Cable Function (from FACTS - i.e., power, control, or instrument)

Fire Area

" Cable from Equipment ID)

" Cable to Equipment ID Page B-84

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.2 Nuclear Safety Capability Circuit Analysis All of the hardcopy data described above is also maintained in a relational database (SAFE-PB).

Comments Reference Document Doc, Details FCS Engineering Analysis EA-FC-97-044 Section 5 Attachment 2 FCS Engineering Analysis EA10-037 Attachment 8, Section 5 and Appendix A Attachment 4 Page B-85

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.2 Nuclear Safety Capability Circuit Analysis NEI 00-01 Re NEI 00-01 Section 3.0 Guidance 3.5 Circuit Analysis and This section on circuit analysis provides information on the potential impact of fire on circuits used to monitor, control and power safe Evaluation shutdown equipment. Applying the circuit analysis criteria will lead to an understanding of how fire damage to the cables may affect the ability to achieve and maintain post-fire safe shutdown in a particular fire area. This section should be used in conjunction with Section 3.4, to evaluate the potential fire-induced impacts that require mitigation. Appendix R Section III.G.2 identifies the fire-induced circuit failure types that are to be evaluated for impact from exposure fires on safe shutdown equipment. Section IllI.G.2 of Appendix R requires consideration of hot shorts, shorts-to-ground and open circuits.

Aoli1cabiliy Comments Applicable Alignment Statement Not Required Allgnment Basis Generic paragraph. Detailed alignment discussed in subsequent reference paragraphs.

Reference Document Doc, Details Page B-86

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.2 Nuclear Safety Capability Circuit Analysis NEI 00-01 Ref NEI 00-01 Section 3.0 Guidance 3.5.1 Criteria/Assumptions Apply the following criteria/assumptions when performing fire-induced circuit failure evaluations.

ADplicability Comments Applicable Alignment Statement Not Required Alianment Basis Generic paragraph. Detailed alignment discussed in subsequent reference paragraphs.

Comments Reference Document Doc. Details Page B-87

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.2 Nuclear Safety Capability Circuit Analysis NEI 00-01 Re NEI 00-01 Section 3.0 Guidance 3.5.1.1 Criteria/Assumptions Consider the following circuit failure types on each conductor of each unprotected safe shutdown cable to determine the potential impact of a fire on the safe shutdown equipment associated with that conductor.

- A hot short may result from a fire-induced insulation breakdown between conductors of the same cable, a different cable or from some other external source resulting in a compatible but undesired impressed voltage or signal on a specific conductor. A hot short may cause a spurious operation of safe shutdown equipment.

- An open circuit may result from a fire-induced break in a conductor resulting in the loss of circuit continuity. An open circuit may prevent the ability to control or power the affected equipment. An open circuit may also result in a change of state for normally energized equipment. (e.g. [for BWRs] loss of power to the Main Steam Isolation Valve (MSIV) solenoid valves due to an open circuit will result in the closure of the MSIVs). Note that RIS 2004-03 indicates that open circuits, as an initial mode of cable failures, are considered to be of very low likelihood. The risk-informed inspection process will focus on failures with relatively high probabilities.

- A short-to-ground may result from a fire-induced breakdown of a cable insulation system, resulting in the potential on the conductor being applied to ground potential. A short-to-ground may have all of the same effects as an open circuit and, in addition, a short-to-ground may also cause an impact to the control circuit or power train of which it is a part.

Consider the three types of circuit failures identified above to occur individually on each conductor of each safe shutdown cable on the required safe shutdown path in the fire area.

Aplicabiliy Comments Applicable Alignment Statement Aligns Alignment Basis Engineering analysis EA-FC-97-044, Section 5.1.2.2:

"Based upon the elementary or scheme drawing and the component wiring diagram, postulate the following cable faults on each cable identified on the drawing:

Open Circuit: The conductor of the circuit opens to interrupt current flow.

Short To Ground: The conductor of the circuit shorts to circuit ground (for grounded circuits only).

Hot Short: The conductor shorts to an energized conductor through a wire to wire short within the cable of concern or through a short to another circuit powered from the same power supply. In the event of a grounded control circuit (i.e., 120 VAC control circuit for a motor operated valve), the hot short source cable does not need to be from the same power source in order to energize the "target" conductor within the cable/component of concern. Hot shorts assume that a "live" wire shorts to a safe shutdown cable conductor, Page B-88

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.2 Nuclear Safety Capability Circuit Analysis causing the safe shutdown circuit to energize inadvertently."

Engineering analysis EA10-037, Attachment 8, Appendix A, Section 3.0:

"The following conditions should be considered when performing cable selection:

Fire-induced cable damage may result in any one, or in a combination of the following circuit failures:

"Open circuits "Shorts to ground "Short circuits" FCS engineering analyses EA-FC-97-044 and EA10-037 consider the effects of open circuits, shorts to ground, and hot shorts in the course of circuit analysis and cable identification activities. The specific methodology used in the consideration of each circuit failure mode is discussed in detail in subsequent reference paragraphs.

Engineering analysis EA10-036, Attachment 12 (the procedure for review and update of the fire area assessment), provides guidance for performing individual fire area assessments. The guidance in the procedure directs the analyst to utilize engineering analysis EA1 0-037, Attachment 8 (the procedure for post fire safe shutdown cable identification), to evaluate circuit failures as a result of fire induced cable damage in a given fire area. The procedure for post fire safe shutdown cable identification is based on the guidelines contained in NEI 00-01.

Comments Reference Document Doc, Details FCS Engineering Analysis EA-FC-97-044 Section 5.1.2.2 FCS Engineering Analysis EA10-037 Attachment 8, Appendix A, Section 3.0 FCS Engineering Analysis EA10-036 Attachment 12 Page B-89

Omaha Public PowerDistrict FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.2 Nuclear Safety Capability Circuit Analysis NEI 00-01 Ref NEI 00-01 Section 3.0 Guidance 3.5.1.2 Criteria/Assumptions Assume that circuit contacts are positioned (i.e., open or closed) consistent with the normal mode/position of the safe shutdown equipment as shown on the schematic drawings. The analyst must consider the position of the safe shutdown equipment for each specific shutdown scenario when determining the impact that fire damage to a particular circuit may have on the operation of the safe shutdown equipment.

Apolicabilit omments Applicable Alignment Statement Aligns Alignment Basis The Table B-2 Nuclear Safety Performance Methodology Review performed for the Fort Calhoun NFPA 805 Transition Project has identified a potential weakness in the Fort Calhoun Appendix R Cable Selection engineering analysis, EA-FC-97-044, regarding the consideration of circuit contact positions (pre and post-fire). This potential weakness was identified in NFPA 805 Transition Project Action Item A2009-076. As closure to A2009-076, FCS performed a review of the cable selection data in Fort Calhoun Appendix R Cable Selection engineering analysis, EA-FC-97-044, to identify and then correct, as necessary, any inadequate cable selection which had not appropriately considered the guidance of NEI 00-01, Section 3.5.1.2, regarding the consideration of circuit contact positions (pre and post-fire). This review included a number of components that are designed to be operated from the Main Control Room and the Primary Control Station (panels AI-179, Al-185, and AI-212) following Main Control Room evacuation. No issues regarding the consideration of circuit contact positions (pre and post-fire) were identified from these reviews. The circuit analysis and cable selection in engineering analysis EA-FC-97-044 has appropriately considered the guidance of NEI 00-01, Section 3.5.1.2, regarding the treatment of circuit contact positions (pre and post-fire) during the circuit analysis and cable selection processes. Consequently, FCS has concluded that the guidance has been implemented consistent with the guidance of NEI 00-01, Section 3.5.1.2.

Engineering analysis EA10-037, Section 4.2, "Assumptions":

"Plant equipment is assumed to be in its normal expected position or condition at the onset of the fire (with the plant at power operation). In cases where the status of equipment is indeterminate or could change as a result of expected plant conditions, worst-case initial conditions are assumed for the purpose of cable selection. The normal position for equipment is identified in Attachment 2, "Combined Appendix R, NFPA 805 Nuclear Safety Performance Criteria, and Fire PRA Equipment List"."

Engineering analysis EA10-036, Attachment 12 (the procedure for review and update of the fire area assessment), provides guidance for performing individual fire area assessments. The guidance in the procedure directs the analyst to utilize engineering analysis EA10-037, Attachment 8 (the procedure for post fire safe shutdown cable identification), to evaluate circuit failures as a result of fire induced cable damage in a given fire area. The procedure for post fire safe shutdown cable identification is based on the guidelines contained in NEI 00-01.

Comments Page B-90

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.2 Nuclear Safety Capability Circuit Analysis Reference Document Doc. Details FCS Engineering Analysis EA-FC-97-044 FCS Engineering Analysis EA10-037 Section 4.2 Attachment 8 FCS Engineering Analysis EA10-036 Attachment 12 Page B-91

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.2 Nuclear Safety Capability Circuit Analysis NEI 00-01 Rf NEI 00-01 Section 3.0 Guidance 3.5.1.3 Criteria/Assumptions Assume that circuit failure types resulting in spurious operations exist until action has been taken to isolate the given circuit from the fire area, or other actions have been taken to negate the effects of circuit failure that is causing the spurious actuation. The fire is not assumed to eventually clear the circuit fault. Note that RIS 2004-03 indicates that fire-induced hot shorts typically self-mitigate after a limited period of time.

AoDlicabilitv Applicable Alignment Statement Aligns Engineering analysis EA-FC-97-044 does not provide explicit guidance or assumptions regarding the self-mitigation of circuit faults. This is an implicit assumption, as Sections 5.1.2.2 and 5.1.2.3 direct the analyst to postulate cable faults without any direction that any circuit faults should be assumed to clear eventually.

Engineering analysis EA10-037, Attachment 8, Appendix A, Section 3.0:

"The circuit analysis and cable selection performed per this procedure shall make no assumptions regarding self-healing of circuits (AC or DC), or circuits shorting to ground after a pre-defined time has passed (AC or DC). Each postulated circuit failure shall be assumed to remain in effect until such time as a positive action has been taken by plant personnel to mitigate the circuit failure."

Engineering analysis EA10-036, Assumption 4.2.10:

"Fire-induced circuit faults are assumed to exist until addressed by a mitigating action. The fire is not assumed to clear the circuit fault after a pre-determined period of time."

Regarding Section 3.5.1.3 of NEI 00-01, the circuit analysis and cable selection methodology utilized for the Fort Calhoun NFPA 805 Transition Project does not make any assumptions regarding self-mitigation of fire-induced hot shorts. The Fort Calhoun NFPA 805 Transition Project assumes that circuit failure types resulting in spurious operations exist until action has been taken to isolate the given circuit from the fire area, or other actions have been taken to negate the effects of circuit failure that is causing the spurious actuation.

Comments Page B-92

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.2 Nuclear Safety Capability Circuit Analysis Reference Document Doc. Details FCS Engineering Analysis EA-FC-97-044 Sections 5.1.2.2 and 5.1.2.3 FCS Engineering Analysis EA10-037 Attachment 8 FCS Engineering Analysis EA10-036 Assumption 4.2.10 Page B-93

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.2 Nuclear Safety Capability Circuit Analysis NEI 00-01 Ref NEI 00-01 Section 3.0 Guidance 3.5.1.4 Criteria/Assumptions When both trains are in the same fire area outside of primary containment, all cables that do not meet the separation requirements of Section III.G.2 are assumed to fail in their worst case configuration.

ADolicabilitv Applicable Alianment Statement Aligns Alignment Basis Engineering analysis EA10-036, Assumption 4.2.1:

"Only a single fire in a single fire area is postulated at a time. The postulated fire is assumed to affect all unprotected cables and equipment within the fire area. This assumes that neither the fire size nor the fire intensity is known. All affected cables are assumed to fail in their worst case configuration."

Comments Reference Document Doc. Details FCS Engineering Analysis EA10-036 Assumption 4.2.1 Page B-94

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.2 Nuclear Safety Capability Circuit Analysis NEI 00-01 Ref NEI 00-01 Section 3.0 Guidance 3.5.1.5 Criteria/Assumptions The following guidance provides the NRC inspection focus from Bin 1 of RIS 2004-03 in order to identify any potential combinations of spurious operations with higher risk significance. Bin 1 failures should also be the focus of the analysis; however, NRC has indicated that other types of failures required by the regulations for analysis should not be disregarded even if in Bin 2 or 3. If Bin 1 changes in subsequent revisions of RIS 2004-03, the guidelines in the revised RIS should be followed.

Cable Failure Modes.

For multiconductor cables testing has demonstrated that conductor-to-conductor shorting within the same cable is the most common mode of failure. This is often referred to as "intra-cable shorting." It is reasonable to assume that given damage, more than one conductor-to-conductor short will occur in a given cable. A second primary mode of cable failure is conductor-to-conductor shorting between separate cables, commonly referred to as "inter-cable shorting." Inter-cable shorting is less likely than intra-cable shorting.

Consistent with the current knowledge of fire-induced cable failures, the following configurations should be considered:

A. For any individual multiconductor cable (thermoset or thermoplastic), any and all potential spurious actuations that may result from intra-cable shorting, including any possible combination of conductors within the cable, may be postulated to occur concurrently regardless of number. However, as a practical matter, the number of combinations of potential hot shorts increases rapidly with the number of conductors within a given cable. For example, a multiconductor cable with three conductors (3C) has 3 possible combinations of two (including desired combinations), while a five conductor cable (5C) has 10 possible combinations of two (including desired combinations), and a seven conductor cable (7C) has 21 possible combinations of two (including desired combinations). To facilitate an inspection that considers most of the risk presented by postulated hot shorts within a multiconductor cable, inspectors should consider only a few (three or four) of the most critical postulated combinations.

B. For any thermoplastic cable, any and all potential spurious actuations that may result from intra-cable and inter-cable shorting with other thermoplastic cables, including any possible combination of conductors within or between the cables, may be postulated to occur concurrently regardless of number. (The consideration of thermoset cable inter-cable shorts is deferred pending additional research.)

C. For cases involving the potential damage of more than one multiconductor cable, a maximum of two cables should be assumed to be damaged concurrently. The spurious actuations should be evaluated as previously described. The consideration of more than two cables being damaged (and subsequent spurious actuations) is deferred pending additional research.

D. For cases involving direct current (DC) circuits, the potential spurious operation due to failures of the associated control cables (even if the spurious operation requires two concurrent hot shorts of the proper polarity, e.g., plus-to-plus and minus-to-minus) should be considered when the required source and target conductors are each located within the same multiconductor cable.

E. Instrumentation Circuits. Required instrumentation circuits are beyond the scope of this associated circuit approach and must meet the same requirements as required power and control circuits. There is one case where an instrument circuit could potentially be considered an associated circuit. If fire-induced damage of an instrument circuit could prevent operation (e.g., lockout permissive signal) or cause maloperation (e.g., unwanted start/stop/reposition signal) of systems necessary to achieve and maintain hot shutdown, then the instrument circuit may be considered an associated circuit and handled accordingly.

Page B-95

Omaha Public Power District FCS NFPA 805 TransitionReport Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.2 Nuclear Safety Capability Circuit Analysis Likelihood of Undesired Consequences Determination of the potential consequence of the damaged associated circuits is based on the examination of specific NPP piping and instrumentation diagrams (P&IDs) and review of components that could prevent operation or cause maloperation such as flow diversions, loss of coolant, or other scenarios that could significantly impair the NPP's ability to achieve and maintain hot shutdown.

When considering the potential consequence of such failures, the [analyst] should also consider the time at which the prevented operation or maloperation occurs. Failures that impede hot shutdown within the first hour of the fire tend to be most risk significant in a first-order evaluation. Consideration of cold-shutdown circuits is deferred pending additional research.

Aelicabiliv Comments Applicable Alignment Statement Aligns Alignment Basis Regarding Sections 3.5.1.5.A through 3.5.1.5.D of NEI 00-01, with the exception as identified below, the circuit analysis and cable selection methodology utilized for the Fort Calhoun NFPA 805 Transition Project in engineering analyses EA10-037 and EA10-036 does not incorporate any binning process, and does not place any limit upon the number of, or combination of concurrent circuit failures (i.e., open circuits, shorts to ground, and/or hot shorts) that are to be assumed by the analyst.

The Fort Calhoun circuit analysis and cable selection methodology does not allow the analyst to pre-screen any cable on the basis of material of construction (i.e., thermoset versus thermoplastic), or on the basis of physical protection within the plant (i.e., the cable provided with ERFBS, or the cable is contained in dedicated metallic conduit).

However, with additional engineering review and justification, these types of features may be credited in the area-by-area review as part of the deterministic analysis.

Engineering analysis EA10-036, Attachment 12 (the procedure for review and update of the fire area assessment), provides guidance for performing individual fire area assessments. The guidance in the procedure directs the analyst to utilize the guidelines contained in Section 3.5 of NEI 00-01 to evaluate circuit failures as a result of fire induced cable damage in a given fire area.

Engineering analysis EA-FC-97-044:

Section 5.1.2.2:

"All AC circuits must consider hot shorts, shorts to ground (for grounded systems), and open circuits. All DC ungrounded circuits must consider hot shorts of positive and negative polarity and open circuits. For high-low pressure interface components, a three phase AC hot short in the proper sequence or two DC hot shorts of the proper polarity must be considered."

Assumption 4.3:

"Fire induced multiple, simultaneous cable faults are not assumed to occur, except for high/low pressure interface components."

Page B-96

Omaha Public Power District FCS NFPA 805 TransitionReport Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.2 Nuclear Safety Capability Circuit Analysis The Table B-2 Nuclear Safety Performance Methodology Review performed for the Fort Calhoun NFPA 805 Transition Project has identified a potential weakness in the Fort Calhoun Appendix R Cable Selection engineering analysis, EA-FC-97-044, regarding the consideration of multiple, simultaneous cable faults. FCS has reviewed cable selection data in Fort Calhoun Appendix R Cable Selection engineering analysis, EA-FC-97-044, and has concluded that the cable selection for Appendix R safe shutdown equipment did not, in practice, result in the omission of safe shutdown cables on the basis of Assumption 4.3 of engineering analysis EA-FC-97-044.

Engineering analysis EA10-037, Attachment 8, Appendix A:

Section 3.0:

"Spurious Operation by Multiple Circuit and/or Cable Failures Although it typically may only take one hot short to cause the spurious operation of a given component, in performing the cable selection, the analyst shall postulate whichever number of circuit and/or cable failures is necessary to cause spurious operation of the component under review, as applicable to the specific component and circuit under review. In other words, circuits and/or cables shall not be excluded on the basis that it requires multiple circuit/cable failures to cause a spurious operation.

3.1 Additional Guidance for the Identification of Cables and Circuits for Safe Shutdown Components for "potentially high-consequence equipment" and Appendix R considerations for "high-low interface" equipment

Three-phase proper polarity hot shorts on AC power systems:

Fire PRA - considers the only credible three-phase proper polarity hot short to be on "potentially high-consequence equipment" with ungrounded or thermoplastic-insulated cables. Grounded AC systems, thermoset-insulated cables, armored cables, or cables in dedicated conduit are not to be included. Fire PRA engineers should identify "high-consequence equipment" during component selection. (Excerpts from NUREG/CR-6850)

Appendix R - considers the only credible three-phase proper polarity hot short to be in cases involving high-low pressure interface components. In all other cases the probability of getting a hot short on all three phases in the proper sequence so as to cause spurious operation of a motor is considered sufficiently low as to not require evaluation.

Systems/mechanical engineers should identify "high-low interface" equipment during component selection. (NEI 00-01 evaluation)

FCS methodology for both Fire PRA and Appendix R: In performing the cable selection, the analyst shall include the power cable for grounded and/or ungrounded AC circuits for any high consequence components (for FPRA) and high low pressure interface components (For Appendix R). This conservative method of performing cable selection for FPRA components may be resolved in the analysis phase per NUREG/CR-6850.

3.2 Additional Guidance for the Identification of Cables and Circuits for Safe Shutdown Components for "Ungrounded DC circuits"

- Compatible Polarity Multiple Hot Shorts on DC circuits Fire PRA: Compatible polarity hot shorts for ungrounded AC and DC circuits are evaluated to be a low-likelihood event; however, sufficient data is unavailable to screen out this particular cable failure mode from consideration. Hence, the evaluation of hot shorts should in general consider this failure mode. (Excerpts from NUREG/CR-6850)

Appendix R: For ungrounded DC circuits, if it can be shown that only two hot shorts of the proper polarity without grounding could cause spurious operation, no further evaluation is necessary except for any cases involving Hi/Lo pressure interfaces. (Excerpts from NEI 00-01)

FCS methodology for both Fire PRA and Appendix R: In performing cable selection for DC valves, the analyst shall include the cable(s) containing the solenoid (or motor Page B-97

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.2 Nuclear Safety Capability Circuit Analysis terminal leads) as a required cable even if the component does not require DC power for the desired safe shutdown function. This conservative method of performing cable selection for Appendix R components may be resolved in the analysis phase per NEI 00-01."

Section 3.5:

"Spurious Signals Spurious signals may result from fire-induced damage to safe shutdown circuits and/or cables. Spurious signal(s) could cause the spurious operation of active and/or passive safe shutdown components. For example, a spuriously induced Safety Injection signal or Containment Isolation signal could cause a system or component to align itself in such a manner as to adversely impact safe shutdown.

The following criteria must be considered in the spurious circuit analysis of a safe shutdown component:

3.5.1 Failure States - For consideration of spurious actuation, all possible functional failure states must be evaluated, that is, the component could be energized or de-energized by one or more failure modes. Therefore, valves could fail open or closed; pumps could fail running or not running; electrical distribution breakers could fail open or closed.

3.5.2 Ungrounded DC Circuits - Cable selection must consider that within control cables two hot shorts of the proper polarity (from the same source) without grounding can cause spurious operation of a component.

3.5.3 Control Signals - The spurious cable selection should address any combination of the failure modes noted in this appendix. Included in this analysis are those cables that could negatively affect contact(s) in the control circuit being analyzed. This analysis may also result in the addition of supporting equipment logics, at which point the process of cable selection should continue by analyzing any newly identified components.

3.5.4 Instrument Signals - (Excerpts from NUREG/CR-6850) Low voltage DC instrument circuits are typically comprised of instrument signal cables for monitoring, protection systems, or control valve circuits (sensor to I/P converter). Shielded, grounded signal cables are typically used for these applications. Considerations in the analysis of these circuits include:

3.5.4.1 Conductor-to-conductor shorts within an instrument signal cable or intermediate resistance grounds can produce false instrument signals that should be considered when determining equipment responses.

3.5.4.2 If the cable design can be verified as one that employs a rugged grounded metallic shield (e.g., armor, braid, etc.), then the analysis need only consider the effects of shorting between the conductors within the shield and shorting of the conductors to ground, i.e., the effects of shorts from external sources need not be considered."

Section 3.2 of NEI 00-01, Safe Shutdown Equipment Selection, contains the criteria/assumption 3.2.1.5 which is also relevant to the previous discussion of Instrumentation Circuits from Section 3.5.1.5 of NEI 00-01:

"Instruments (e.g., resistance temperature detectors, thermocouples, pressure transmitters, and flow transmitters) are assumed to fail upscale, midscale, or downscale as a result of fire damage, whichever is worse. An instrument performing a control function is assumed to provide an undesired signal to the control circuit."

Regarding Section 3.5.1.5.E of NEI 00-01, The Table B-2 Nuclear Safety Performance Methodology Review performed for the Fort Calhoun NFPA 805 Transition Project has identified a potential weakness in the Fort Calhoun Appendix R Cable Selection engineering analysis, EA-FC-97-044, regarding the consideration of instrument failure modes, Page B-98

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.2 Nuclear Safety Capability Circuit Analysis and instrumentation circuit failure modes. This potential weakness was identified in NFPA 805 Transition Project Action Item A2009-078. As closure to A2009-078, FCS performed a review of the cable selection data in Fort Calhoun Appendix R Cable Selection engineering analysis, EA-FC-97-044, to identify and then correct, as necessary, any inadequate cable selection which had not appropriately considered the guidance of NEI 00-01, Sections 3.2.1.5 and 3.5.1.5, regarding the consideration of instrument failure modes, and instrumentation circuit failure modes. This review identified several safe shutdown valves that were not adequately cable selected and could spuriously operate due to the instrument and instrumentation circuit failure modes. The corrected cable selection packages for the associated safe shutdown valves (LCV-101-1, LCV-101-2, PCV-103-1, and PCV-103-2) were incorporated into engineering analysis EA10-037. (Ref. CR2010-2173)

FCS Engineering Analysis EA-FC-97-044 Section 5.1.2.2 Assumption 4.3 FCS Engineering Analysis EA10-037 Sections 3.0 and 3.5 FCS Engineering Analysis EA10-036 Attachment 12 Page B-99

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.2 Nuclear Safety Capability Circuit Analysis NEI 00-01 Rf NEI 00-01 Section 3.0 Guidance 3.5.2 Types of Circuit Failures Appendix R requires that nuclear power plants must be designed to prevent exposure fires from defeating the ability to achieve and maintain post-fire safe shutdown. Fire damage to circuits that provide control and power to equipment on the required safe shutdown path and any other equipment whose spurious operation/mal-operation could affect shutdown in each fire area must be evaluated for the effects of a fire in that fire area. Only one fire at a time is assumed to occur. The extent of fire damage is assumed to be limited by the boundaries of the fire area. Given this set of conditions, it must be assured that one redundant train of equipment capable of achieving hot shutdown is free of fire damage for fires in every plant location. To provide this assurance, Appendix R requires that equipment and circuits required for safe shutdown be free of fire damage and that these circuits be designed for the fire-induced effects of a hot short, short-to-ground, and open circuit. With respect to the electrical distribution system, the issue of breaker coordination must also be addressed.

This section will discuss specific examples of each of the following types of circuit failures:

- Open circuit

- Short-to-ground

- Hot short.

ADDlicabilitv Comments Applicable Alianment Statement Not Required Alianment Basis Generic paragraph. Detailed alignment discussed in subsequent reference paragraphs.

Comments Reference Document Page B-100

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.2 Nuclear Safety Capability Circuit Analysis NEI 00 Ref NEI 00-01 Section 3.0 Guidance 3.5.2.1 Circuit Failures Due to an This section provides guidance for addressing the effects of an open circuit for safe shutdown equipment. An open circuit is a fire-Open Circuit induced break in a conductor resulting in the loss of circuit continuity. An open circuit will typically prevent the ability to control or power the affected equipment. An open circuit can also result in a change of state for normally energized equipment. For example, a loss of power to the main steam isolation valve (MSIV) solenoid valves [for BWRs] due to an open circuit will result in the closure of the MSIV.

NOTE: The EPRI circuit failure testing indicated that open circuits are not likely to be the initial fire-induced circuit failure mode.

Consideration of this may be helpful within the safe shutdown analysis. Consider the following consequences in the safe shutdown circuit analysis when determining the effects of open circuits:

- Loss of electrical continuity may occur within a conductor resulting in deenergizing the circuit and causing a loss of power to, or control of, the required safe shutdown equipment.

- In selected cases, a loss of electrical continuity may result in loss of power to an interlocked relay or other device. This loss of power may change the state of the equipment. Evaluate this to determine if equipment fails safe.

- Open circuit on a high voltage (e.g., 4.16 kV) ammeter current transformer (CT) circuit may result in secondary damage.

Alicabilitv Comments Applicable Alignment Statement Aligns Alignment Basis Engineering analysis EA-FC-97-044:

Section 5.1.2.2:

"Open Circuit: The conductor of the circuit opens to interrupt current flow."

Section 5.1.2.3:

"The given or NORMAL position of the component along with the DESIRED and FAIL positions of the component will determine which cables may impact the component's ability to perform its safe shutdown function. Components which are desired in more than one position should be analyzed in each position. Based upon the component positions identified in calculation FC06355, "10 CFR 50 Appendix R Functional Requirements and Component Selection", each cable should be analyzed to determine the possible fault consequences for each conductor. The possible fault consequences are as follows:

LOP Cable fault will result in loss of motive power.

Page B-101

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.2 Nuclear Safety Capability Circuit Analysis LOC Cable fault will result in loss of control capability (including loss of control power).

LOC (FO) Cable fault will result in loss of control power, failing the valve open (applicable only for safe shutdown valves).

LOC (FC) Cable fault will result in loss of control power, failing the valve closed (applicable only for safe shutdown valves).

SPUR Cable fault will spuriously operate the component to an undesired position.

LOI Cable fault will result in loss of safe shutdown indication (including loss of instrument power supply cables)."

Engineering analysis EA10-037, Attachment 8, Appendix A, Section 3.0:

"Circuit Failures Due to an Open Circuit An open circuit is a fire-induced break in a conductor resulting in the loss of circuit continuity. An open circuit will typically prevent the ability to control or power the affected equipment. An open circuit can also result in a change of state for normally energized equipment.

NOTE: Despite the EPRI circuit failure testing indicated that open circuits are not likely to be the initial fire-induced circuit failure mode, the EPRI testing was only done under high temperature considerations, however the structure damage (or tray breaking as a result of a fire) were not considered. Open circuits are postulated to occur during fires.

Consider the following consequences in the safe shutdown circuit analysis when determining the effects of open circuits:

- Loss of electrical continuity may occur within a conductor resulting in de-energizing the circuit and causing a loss of power to, or control of, the required safe shutdown equipment.

- In selected cases, a loss of electrical continuity may result in loss of power to an interlocked relay or other device. This loss of power may change the state of the equipment.

Evaluate this to determine if equipment fails safe.

- Open circuit on a high voltage (e.g. 4.16 kV) ammeter current transformer (CT) circuit may result in secondary damage."

The Fort Calhoun assessment for circuit failures due to open circuits in the secondary windings of current transformers is provided in Attachment 11, "Associated Circuits Review", in engineering analysis EA10-036 "Fort Calhoun Station Automation and Update of Safe Shutdown Analysis". It should be noted that the Current Transformer (CT) assessment was not previously included in the Fort Calhoun Appendix R program, but it has been added in this report to support the transition to NFPA 805.

Engineering analysis EA10-036, Attachment 12 (the procedure for review and update of the fire area assessment), provides guidance for performing individual fire area assessments. The guidance in the procedure directs the analyst to utilize the guidelines contained in Section 3.5 of NEI 00-01 to evaluate circuit failures as a result of fire induced cable damage in a given fire area.

Comments Reference Document Doc, Details FCS Engineering Analysis EA-FC-97-044 Sections 5.1.2.2 and 5.1.2.3 FCS Engineering Analysis EA10-037 Attachment 8, Appendix A, Section 3.0 FCS Engineering Analysis EA10-036 Attachments 11 and 12 Page B-102

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.2 Nuclear Safety Capability Circuit Analysis NEI00-01 Ref NEI 00-01 Section 3.0 Guidance 3.5.2.2 Circuit Failures Due to a This section provides guidance for addressing the effects of a short-to-ground on circuits for safe shutdown equipment. A short-to-Short-to-Ground ground is a fire-induced breakdown of a cable insulation system resulting in the potential on the conductor being applied to ground potential. A short-to-ground can cause a loss of power to or control of required safe shutdown equipment. In addition, a short-to-ground may affect other equipment in the electrical power distribution system in the cases where proper coordination does not exist. Consider the following consequences in the post-fire safe shutdown analysis when determining the effects of circuit failures related to shorts-to-ground:

- A short to ground in a power or a control circuit may result in tripping one or more isolation devices (i.e. breaker/fuse) and causing a loss of power to or control of required safe shutdown equipment.

- In the case of certain energized equipment such as HVAC dampers, a loss of control power may result in loss of power to an interlocked relay or other device that may cause one or more spurious operations.

ADnlicabilitv Applicable Alignment Statement Aligns Alignment Basis Engineering analysis EA-FC-97-044:

Section 5.1.2.2:

"Short To Ground: The conductor of the circuit shorts to circuit ground (for grounded circuits only)."

Section 5.1.2.3:

"The given or NORMAL position of the component along with the DESIRED and FAIL positions of the component will determine which cables may impact the component's ability to perform its safe shutdown function. Components which are desired in more than one position should be analyzed in each position. Based upon the component positions identified in calculation FC06355, "10 CFR 50 Appendix R Functional Requirements and Component Selection", each cable should be analyzed to determine the possible fault consequences for each conductor. The possible fault consequences are as follows:

LOP Cable fault will result in loss of motive power.

LOC Cable fault will result in loss of control capability (including loss of control power).

LOC (FO) Cable fault will result in loss of control power, failing the valve open (applicable only for safe shutdown valves).

LOC (FC) Cable fault will result in loss of control power, failing the valve closed (applicable only for safe shutdown valves).

Page B-103

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.2 Nuclear Safety Capability Circuit Analysis SPUR Cable fault will spuriously operate the component to an undesired position.

LOI Cable fault will result in loss of safe shutdown indication (including loss of instrument power supply cables)."

Table B-2 Nuclear Safety Performance Methodology Review performed for the Fort Calhoun NFPA 805 Transition Project has identified a potential weakness in the Fort Calhoun Appendix R Cable Selection engineering analysis, EA-FC-97-044, regarding the consideration for multiple DC grounds. This potential weakness was identified in NFPA 805 Transition Project Action Items A2009-057, A2009-058, A2009-077, and A2009-128. As closure to A2009-077, FCS performed a review of the cable selection data in Fort Calhoun Appendix R Cable Selection engineering analysis, EA-FC-97-044, to identify and then correct, as necessary, any inadequate cable selection that previously did not consider multiple DC grounds. This review identified a number of DC control circuits for various safe shutdown components that were not adequately cable selected and could lose DC control power due to multiple DC grounds. The corrected cable selection packages (CH-1A, CH-1 B, EE-57, FW-10, FW-4A, FW-4B, FW-4C, FW-54, RC-3A, RC-3B, RC-3C, RC-3D, SI-1A, SI-1B, SI-2C, and YCV-1045) for the associated safe shutdown components were incorporated into engineering analysis EA10-037. (Ref. CR2009-271 1, CR2011-0770, and CR2011-0964)

Engineering analysis EA10-037, Attachment 8, Appendix A, Section 3.0:

"Circuit Failures Due to a Short-to-Ground A short-to-ground is a fire-induced breakdown of a cable insulation system resulting in the potential on the conductor being applied to ground potential. A short-to-ground can cause a loss of power to or control of required safe shutdown equipment. In addition, a short-to-ground may affect other equipment in the electrical power distribution system in the cases where proper coordination does not exist.

Consider the following consequences in the post-fire safe shutdown analysis when determining the effects of circuit failures related to shorts-to-ground:

- A short to ground in a power or a control circuit may result in tripping one or more isolation devices (i.e. breaker/fuse) and causing a loss of power to or control of required safe shutdown equipment.

- In the case of certain energized equipment such as HVAC dampers, a loss of control power may result in loss of power to an interlocked relay or other device that may cause one or more spurious operations.

Short-to-Ground on Grounded Circuits Typically, in the case of a grounded circuit, a short-to-ground on any part of the circuit would present a concern for tripping the circuit isolation device thereby causing a loss of control power.

Short-to-Ground on Ungrounded Circuits In the case of an ungrounded circuit, postulating only a single short-to-ground on any part of the circuit may not result in tripping the circuit isolation device. Another short-to-ground on the circuit or another circuit from the same source would need to exist to cause a loss of control power to the circuit. Multiple grounds in ungrounded systems should always be assumed."

Engineering analysis EA10-036, Attachment 12 (the procedure for review and update of the fire area assessment), provides guidance for performing individual fire area assessments. The guidance in the procedure directs the analyst to utilize the guidelines contained in Section 3.5 of NEI 00-01 to evaluate circuit failures as a result of fire induced cable damage in a given fire area.

Page B-104

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.2 Nuclear Safety Capability Circuit Analysis Comments Reference Document Doc. Details FCS Engineering Analysis EA-FC-97-044 Sections 5.1.2.2 and 5.1.2.3 FCS Engineering Analysis EA10-037 Attachment 8, Appendix A, Section 3.0 FCS Engineering Analysis EA10-036 Attachment 12 Page B-105

Omaha Public Power District FCS NFPA 805 TransitionReport Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.2 Nuclear Safety Capability Circuit Analysis NEI 00-01 Rif NEI 00-01 Section 3.0 Guidance 3.5.2.3 Circuit Failures Due to a This section provides guidance for analyzing the effects of a hot short on circuits for required safe shutdown equipment. A hot short is Hot Short defined as a fire induced insulation breakdown between conductors of the same cable, a different cable or some other external source resulting in an undesired impressed voltage on a specific conductor. The potential effect of the undesired impressed voltage would be to cause equipment to operate or fail to operate in an undesired manner.

Consider the following specific circuit failures related to hot shorts as part of the post-fire safe shutdown analysis:

- A hot short between an energized conductor and a de-energized conductor within the same cable may cause a spurious actuation of equipment. The spuriously actuated device (e.g., relay) may be interlocked with another circuit that causes the spurious actuation of other equipment. This type of hot short is called a conductor-to-conductor hot short or an internal hot short.

- A hot short between any external energized source such as an energized conductor from another cable (thermoplastic cables only) and a de-energized conductor may also cause a spurious actuation of equipment. This is called a cable-to-cable hot short or an external hot short. Cable-to-cable hot shorts between thermoset cables are not postulated to occur pending additional research.

ADolicabilit Comments Applicable Alignment Statement Aligns Alignment Basis Engineering analysis EA-FC-97-044:

Section 5.1.2.2:

"Hot Short: The conductor shorts to an energized conductor through a wire to wire short within the cable of concern or through a short to another circuit powered from the same power supply. In the event of a grounded control circuit (i.e., 120 VAC control circuit for a motor operated valve), the hot short source cable does not need to be from the same power source in order to energize the "target" conductor within the cable/component of concern. Hot shorts assume that a "live" wire shorts to a safe shutdown cable conductor, causing the safe shutdown circuit to energize inadvertently."

Section 5.1.2.3:

"The given or NORMAL position of the component along with the DESIRED and FAIL positions of the component will determine which cables may impact the component's ability to perform its safe shutdown function. Components which are desired in more than one position should be analyzed in each position. Based upon the component positions identified in calculation FC06355, "10 CFR 50 Appendix R Functional Requirements and Component Selection", each cable should be analyzed to determine the possible fault consequences for each conductor. The possible fault consequences are as follows:

Page B-106

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.2 Nuclear Safety Capability Circuit Analysis LOP Cable fault will result in loss of motive power.

LOC Cable fault will result in loss of control capability (including loss of control power).

LOC (FO) Cable fault will result in loss of control power, failing the valve open (applicable only for safe shutdown valves).

LOC (FC) Cable fault will result in loss of control power, failing the valve closed (applicable only for safe shutdown valves).

SPUR Cable fault will spuriously operate the component to an undesired position.

LOI Cable fault will result in loss of safe shutdown indication (including loss of instrument power supply cables)."

Engineering analysis EA10-037, Attachment 8, Appendix A, Section 3.0:

"A hot short is defined as a fire-induced insulation breakdown between conductors of the same cable, a different cable or some other external source resulting in an undesired impressed voltage on a specific conductor. A potential effect of the undesired impressed voltage would be to cause equipment to operate or fail to operate in an undesired manner.

Consider the following specific circuit failures related to hot shorts as part of the post-fire safe shutdown analysis:

- Revision 2 of NEI 00-01 identifies that for components important to safe shutdown, the duration of a hot short may be limited to 20 minutes, and that after 20 minutes the hot short may be assumed to go to ground. However, the NRC does not endorse this assumption for DC circuits (see NRC Regulatory Guide 1.189, section 5.3), accordingly induced fire failure on DC circuits should be considered with no failure time limit.

A hot short between an energized conductor and a de-energized conductor within the same cable may cause a spurious actuation of equipment. The spuriously actuated device (e.g., relay) may be interlocked with another circuit that causes the spurious actuation of other equipment. This type of hot short is called a conductor-to-conductor hot short, an internal hot short, or an intra-cable short.

- A hot short between any external energized source such as an energized conductor from another cable and a de-energized conductor may also cause a spurious actuation of equipment. This is called a cable-to-cable hot short, an external hot short, or an inter-cable short.

The circuit analysis and cable selection performed per this procedure shall make no assumptions regarding self-healing of circuits (AC or DC), or circuits shorting to ground after a pre-defined time has passed (AC or DC). Each postulated circuit failure shall be assumed to remain in effect until such time as a positive action has been taken by plant personnel to mitigate the circuit failure.

A Hot Short on Grounded Circuits A short-to-ground is a more likely failure mode for a grounded control circuit. A short-to-ground as described above would result in de-energizing the circuit. This would further reduce the likelihood for the circuit to change the state of the equipment either from a control switch or due to a hot short. Nevertheless, a hot short still needs to be considered.

A Hot Short on Ungrounded Circuits In the case of an ungrounded circuit, a single hot short may be sufficient to cause a spurious operation. A single hot short can cause a spurious operation if the hot short comes from a circuit from the positive leg of the same ungrounded source as the affected circuit.

In performing the cable selection, the analyst shall not exclude any cables from being required based upon the likelihood of external hot shorts due to cable insulation properties (i.e., the RIS 2004-03 criteria for thermoset versus thermoplastic insulated cables), or due to the fact that a cable may be routed in a dedicated conduit, or otherwise protected (i.e., wrapped or embedded raceways)."

Engineering analysis EA10-036, Attachment 12 (the procedure for review and update of the fire area assessment), provides guidance for performing individual fire area Page B-107

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.2 Nuclear Safety Capability Circuit Analysis assessments. The guidance in the procedure directs the analyst to utilize the guidelines contained in Section 3.5 of NEI 00-01 to evaluate circuit failures as a result of fire induced cable damage in a given fire area.

Comments Reference Document Doc, Details FCS Engineering Analysis EA-FC-97-044 Sections 5.1.2.2 and 5.1.2.3 FCS Engineering Analysis EA10-037 Attachment 8, Appendix A, Section 3.0 FCS Engineering Analysis EAI0-036 Attachment 12 Page B-108

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.2 Nuclear Safety Capability Circuit Analysis NEI 00-01 Ref NEI 00-01 Section 3.0 Guidance 3.5.2.4 Circuit Failures Due to The evaluation of associated circuits of a common power source consists of verifying proper coordination between the supply Inadequate Circuit breaker/fuse and the load breakers/fuses for power sources that are required for safe shutdown. The concern is that, for fire damage to Coordination a single power cable, lack of coordination between the supply breaker/fuse and the load breakers/fuses can result in the loss of power to a safe shutdown power source that is required to provide power to safe shutdown equipment.

A coordination study should demonstrate the coordination status for each required common power source. For coordination to exist, the time-current curves for the breakers, fuses and/or protective relaying must demonstrate that a fault on the load circuits is isolated before tripping the upstream breaker that supplies the bus. Furthermore, the available short circuit current on the load circuit must be considered to ensure that coordination is demonstrated at the maximum fault level.

The methodology for identifying potential associated circuits of a common power source and evaluating circuit coordination cases of associated circuits on a single circuit fault basis is as follows:

- Identify the power sources required to supply power to safe shutdown equipment.

- For each power source, identify the breaker/fuse ratings, types, trip settings and coordination characteristics for the incoming source breaker supplying the bus and the breakers/fuses feeding the loads supplied by the bus.

- For each power source, demonstrate proper circuit coordination using acceptable industry methods.

- For power sources not properly coordinated, tabulate by fire area the routing of cables whose breaker/fuse is not properly coordinated with the supply breaker/fuse. Evaluate the potential for disabling power to the bus in each of the fire areas in which the associated circuit cables of concern are routed and the power source is required for safe shutdown. Prepare a list of the following information for each fire area:

- Cables of concern.

- Affected common power source and its path.

- Raceway in which the cable is enclosed.

- Sequence of the raceway in the cable route.

- Fire zone/area in which the raceway is located.

For fire zones/areas in which the power source is disabled, the effects are mitigated by appropriate methods.

- Develop analyzed safe shutdown circuit dispositions for the associated circuit of concern cables routed in an area of the same path as required by the power source. Evaluate adequate separation based upon the criteria in Appendix R, NRC staff guidance, and plant licensing bases.

Page B-109

Omaha Public Power District FCS NFPA 805 TransitionReport Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.2 Nuclear Safety Capability Circuit Analysis Ap~licabili* Comments Applicable Alionment Statement Aligns Alignment Basis The Fort Calhoun assessment for circuit failures due to inadequate circuit coordination is provided in Attachment 11, "Associated Circuits Review", in engineering analysis EA10-036, "Fort Calhoun Station Automation and Update of Safe Shutdown Analysis".

Calculation FC05188, Section 1.0:

"The purpose of this calculation is to determine the short circuit contribution to the 120Vac Instrument Buses via inverters. Also, this calculation evaluates the available short circuit current at several levels downstream of the instrument buses with respect to their associated protective devices' trip settings. Short circuit calculations are performed on the four CQE inverter systems A, B, C, D, EE-8T and EE-8U and two non-CQE inverter systems 1 and 2. Coordination studies are conducted to ensure that the protective devices in each inverter system are properly coordinated against the postulated short circuit faults."

FC05188 demonstrates selective circuit coordination for the vital 120 VAC electrical distribution network, down to the branch fuses.

Engineering analysis EA-FC-91-084, Section 2.0:

"This Breaker/Fuse Coordination Study shall encompass all electrical buses at the station as shown on reference 3.2.1, namely 4160 V and 480V switchgear, 480V MCCs, 120 VAC 1 C3A & 1 C4A buses, and the 125 VDC buses. The associated protective devices for each bus will be identified and modeled in CAPTOR. Short circuit and breaker/fuse coordination for 120 VAC instrument buses are analyzed and documented in Calculation FC05188 (Ref. 3.1.1) and are not included in this analysis. The operation of protective devices is established from the graphic representation of the time-current characteristic curves (TCC) for these devices. By plotting these TCCs on a common graph, the relationship of the characteristics among the protective devices is immediately apparent. Potential trouble spots such as overlapping of curves or unnecessarily long time intervals between devices will be revealed.

Each bus shall have protective device characteristic curves generated containing upstream overcurrent protective devices and the largest branch circuit protective device. The largest branch circuit protective device is defined as the device whose characteristic curve has the highest current clearing time of all the branch circuits off of that bus. These TCCs will be plotted on one drawing."

Engineering analysis EA-FC-91-084 demonstrates selective circuit coordination for the vital 4kV, 480V, and 125 VDC electrical distribution network, down to the branch fuses.

Comments 1 of EA10-036 refers to FCS calculation FC05188 and FCS engineering analysis EA-FC-91-084 regarding the acceptability of circuit coordination.

Page B-110

Omaha Public PowerDistrict FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.2 Nuclear Safety Capability Circuit Analysis Reference Document Doc. Details FCS Calculation FC05188 Section 1.0 FCS Engineering Analysis EA-FC-91-084 Section 2.0 FCS Engineering Analysis EA10-036 Attachment 11 Page B-111

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.2 Nuclear Safety Capability Circuit Analysis NEI 00-01 Ref NEI 00-01 Section 3.0 Guidance 3.5.2.5 Circuit Failures Due to The common enclosure associated circuit concern deals with the possibility of causing secondary failures due to fire damage to a Common Enclosure circuit either whose isolation device fails to isolate the cable fault or protect the faulted cable from reaching its ignition temperature, or Concerns the fire somehow propagates along the cable into adjoining fire areas.

The electrical circuit design for most plants provides proper circuit protection in the form of circuit breakers, fuses and other devices that are designed to isolate cable faults before ignition temperature is reached. Adequate electrical circuit protection and cable sizing are included as part of the original plant electrical design maintained as part of the design change process. Proper protection can be verified by review of as-built drawings and change documentation. Review the fire rated barrier and penetration designs that preclude the propagation of fire from one fire area to the next to demonstrate that adequate measures are in place to alleviate fire propagation concerns.

A Dolicabilit~

Applicable Alignment Statement Aligns Alignment Basis The Fort Calhoun assessment for circuit failures due to common enclosure concerns is provided in Attachment 11, "Associated Circuits Review", in engineering analysis EA10-036, "Fort Calhoun Station Automation and Update of Safe Shutdown Analysis".

Comments Reference Document Doc. Details FCS Engineering Analysis EA10-036 Attachment 11 Page B-112

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.3 Nuclear Safety Equipment and Cable Location Physical location of equipment and cables shall be identified.

NEI 00-01 Re NEI 00-01 Section 3.0 Guidance 3.3.3.4 Identify Routing of Cables Identify the routing for each cable including all raceway and cable endpoints. Typically, this information is obtained from joining the list of safe shutdown cables with an existing cable and raceway database.

ADnlicabilitv Comments Applicable Alignment Statement Aligns Fort Calhoun Automated Cable Tracking System (FACTS)

Cable routing information is maintained in the Fort Calhoun Automated Cable Tracking System (FACTS). This information includes the following:

"Cable ID "Origin (from Equipment ID)

" Destination (to Equipment ID)

" Routing (raceway sections)

Comments Reference Document Doc. Details Page B-113

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.3 Nuclear Safety Equipment and Cable Location NEI 00-01 Ref NEI 00-01 Section 3.0 Guidance 3.3.3.5 Identify Location of Identify the fire area location of each raceway and cable endpoint identified in the previous step and join this information with the cable Raceway and Cables by routing data. In addition, identify the location of field-routed cable by fire area. This produces a database containing all of the cables Fire Area requiring fire area analysis, their locations by fire area, and their raceway.

AoliCabilitv Comments Applicable Alignment Statement Aligns Alignment Basis Engineering analysis EA10-037, Attachment 9, Section 5; and engineering analysis EA10-037, Attachment 6 and Attachment 7:

The FCS Appendix R and NFPA 805 safe shutdown analyses both assign fire area locations directly to safe shutdown equipment and safe shutdown cables. Neither the Appendix R nor the NFPA 805 analyses maintain the relationships between safe shutdown cables and their associated raceways and cable endpoints, or the fire area location for the cable raceways and cable endpoints.

The assignment of fire area locations to each safe shutdown cable includes the fire area(s) of the cable via raceway sections, conduits, and the fire areas of the cable to and from destination equipment. The cable raceway via sections and the cable to and from destination equipment is provided by the FCS Automated Cable Tracking System (FACTS).

The assignment of fire area locations to safe shutdown equipment and safe shutdown cables involves use of the plant fire area partitioning boundary drawings, and plant conduit and raceway sections plan layout drawings. The general process involves tracing the cable from origin to destination on the plant conduit and raceway sections plan layout drawings and then assigning fire areas to the cable based on the aforementioned plant fire area partitioning boundary drawings. A similar process is utilized for safe shutdown equipment, which may also be supplemented by other controlled plant documents and/or walkdowns for nonelectrical plant equipment (i.e., manual valves, etc.).

For new safe shutdown cables added to support the Fire PRA and NFPA 805, the documentation associated with this process is maintained on cable fire area location data sheets as Attachment 5 to engineering analysis EA10-037.

For the legacy Appendix R cables that were previously assigned fire area locations in FCS engineering analysis, EA-FC-97-044, there is no documentation associated with this process. However, the NFPA 805 Transition Project included Task 4.6 and Task 4.7 to verify the accuracy of the legacy Appendix R safe shutdown cable fire area location data.

Task 4.6 was a sampling study performed by FCS to verify the fire area locations from EA-FC-97-044 for approximately 200 of the 2000 legacy Appendix R safe shutdown cables. Task 4.6 was documented in Letter from Westinghouse Electric Company (G. D. Auld) to OPPD (J. Mcmanis), "Omaha Public Power District, Fort Calhoun Station, NFPA 805 Fire PRA, NFPA 805 - Task 4.6 Sample Cable/Raceway Fire Area Location," dated July 27, 2009 (CFTC-09-56). The results of Task 4.6 were used to define the scope of Task 4.7, based on informed decisions to not verify the fire area locations for some cables (i.e., excluding cables contained entirely within the Containment, Main Control Room/Cable Spreading Room, Intake Structure, cable of less than 15 feet in length, etc.). Task 4.7 was performed by FCS personnel to verify the fire area locations from EA-FC-97-044 for a significant remainder of the legacy Appendix R safe shutdown cables. Task 4.7 was documented in Fort Calhoun engineering change EC50655, Revision 0, "FACTS Enhancements Identified During NFPA 805". The verifications performed for Task 4.6 and Task 4.7 were documented similarly to the cable location data Page B-114

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.3 Nuclear Safety Equipment and Cable Location sheets contained in this report. Safe shutdown cables that were found to require fire area location changes as the result of Task 4.6 and Task 4.7 were tracked through the FCS condition report process. (Ref. Task 4.6 - CR2010-2206; and Task 4.7 - CR2010-2202, CR2010-6640, CR2011-0733, CR2011-0759, and CR2011-1007)

Engineering analysis EA10-037, Attachment 6, provides a table of every cable required for the FCS NFPA 805 at-power safe shutdown model, the Fire PRA, and the NFPA 805 non-power operations model. This table includes the following:

Equipment ID

Associated Cable ID

Cable Function (from FACTS - i.e., power, control, or instrument)

" Fire Area

" Cable from Equipment ID)

Cable to Equipment ID Engineering analysis EA10-037, Attachment 7, provides a table of every cable analyzed in the FCS NFPA 805 at-power safe shutdown model, the Fire PRA, and the NFPA 805 non-power operations model. This table includes the following:

" Equipment ID "Associated Cable ID

" Cable Function (from FACTS - i.e., power, control, or instrument)

" Fire Area

Cable from Equipment ID)

" Cable to Equipment ID All of the hardcopy data described above is also maintained in a relational database (SAFE-PB).

Comments Reference Document Doc. Details FCS Engineering Analysis EA10-037 Attachment 9, Section 5 Attachment 6 Attachment 7 Westinghouse Letter CFTC-09-56 FCS Engineering Change EC50655 Page B-115

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.4 Fire Area Assessment An engineering analysis shall be performed in accordance with the requirements of Section 2.3 for each fire area to determine the effects of fire or fire suppression activities on the ability to achieve the nuclear safety performance criteria of Section 1.5. See Chapter 4 for methods of achieving these performance criteria (performance-based or deterministic).

NEI00-01 Rf NEI 00-01 Section 3.0 Guidance 3.4 Fire Area Assessment and By determining the location of each component and cable by fire area and using the cable to equipment relationships described above, Compliance Strategies the affected safe shutdown equipment in each fire area can be determined. Using the list of affected equipment in each fire area, the impacts to safe shutdown systems, paths and functions can be determined. Based on an assessment of the number and types of these impacts, the required safe shutdown path for each fire area can be determined. The specific impacts to the selected safe shutdown path can be evaluated using the circuit analysis and evaluation criteria contained in Section 3.5 of this document. Having identified all impacts to the required safe shutdown path in a particular fire area, this section provides guidance on the techniques available for individually mitigating the effects of each of the potential impacts.

ADlicability Comments Applicable Alianment Statement Not Required Alianment Basis Generic paragraph. Detailed alignment discussed in subsequent reference paragraphs.

Comments Reference Document Page B- 116

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.4 Fire Area Assessment NEI00-01 Ref NEI 00-01 Section 3.0 Guidance 3.4.1 Criteria/Assumptions The following criteria and assumptions apply when performing fire area compliance assessment to mitigate the consequences of the circuit failures identified in the previous sections for the required safe shutdown path in each fire area.

Applicabilitv Applicable Alignment Statement Not Required Alignment Basis Generic paragraph. Detailed alignment discussed in subsequent reference paragraphs.

Comments Reference Document Page B- 117

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.4 Fire Area Assessment NEI 00-01 Ref NEI 00-01 Section 3.0 Guidance 3.4.1.1 Criteria/Assumptions Assume only one fire in any single fire area at a time.

ADRlicability Comments Applicable Alianment Statement Aligns Alianment Basis Engineering analysis EA10-036, Assumption 4.2.1:

"Only a single fire in a single fire area is postulated at a time. The postulated fire is assumed to affect all unprotected cables and equipment within the fire area. This assumes that neither the fire size nor the fire intensity is known. All affected cables are assumed to fail in their worst case configuration."

Comments Reference Document Doc, Details FCS Engineering Analysis EA10-036 Assumption 4.2.1 Page B-118

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.4 Fire Area Assessment NE0I0 Ref NEI 00-01 Section 3.0 Guidance 3.4.1.2 Criteria/Assumptions Assume that the fire may affect all unprotected cables and equipment within the fire area. This assumes that neither the fire size nor the fire intensity is known. This is conservative and bounds the exposure fire that is required by the regulation.

AD~licabilit Applicable Alianment Statement Aligns Alignment Basis Engineering analysis EA10-036, Assumption 4.2.1:

"Only a single fire in a single fire area is postulated at a time. The postulated fire is assumed to affect all unprotected cables and equipment within the fire area. This assumes that neither the fire size nor the fire intensity is known. All affected cables are assumed to fail in their worst case configuration."

Comments Reference Document Doc. Details FCS Engineering Analysis EA10-036 Assumption 4.2.1 Page B-119

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.4 Fire Area Assessment NEI 00-01 Ref NEI 00-01 Section 3.0 Guidance 3.4.1.3 Criteria/Assumptions Address all cable and equipment impacts affecting the required safe shutdown path in the fire area. All potential impacts within the fire area must be addressed. The focus of this section is to determine and assess the potential impacts to the required safe shutdown path selected for achieving post-fire safe shutdown and to assure that the required safe shutdown path for a given fire area is properly protected.

Aoolicabilit Comments Applicable Alignment Statement Aligns with Intent Alignment Basis Engineering analysis EA10-036, Section 4.10:

Engineering analysis EA10-036, Attachment 12 (the procedure for review and update of the fire area assessment) describes the guidelines utilized to perform the automated deterministic fire area analysis using SAFE-PB software tool.

"The analysis is typically performed through an iterative process, with each iteration postulating a full area burn fire in the associated plant fire area. The analyst is to initially assume that all of the fire affected equipment in the fire area fails to the worst case position or status. In the initial iteration, the full area burn fails all of the safe shutdown cables and equipment located within the analyzed area. Consequently, other safe shutdown equipment also fail based on the logical associations to the directly fire affected equipment and cables, which in turn may fail other equipment, systems, and performance goals in the safe shutdown model. The safe shutdown model includes plant components whose fire induced spurious operation, alone, or in combination, could be adverse to one or more success paths associated with each performance goal, as applicable. As a result of the initial full area burn analysis in SAFE-PB, the analyst is provided with all of the potentially fire affected safe shutdown paths, systems, equipment, and cables in the analyzed fire area.

To resolve the deterministic analysis for each fire area, the analyst first reviews the initial area results to determine the least affected electrical distribution and mechanical support systems, and then identifies the key equipment and cable failures associated with these electrical distribution and mechanical support systems that must be addressed to recover a least one train of these systems. These key failures are further analyzed to determine the true nature of the fire impact, which are then documented as SAFE-PB equipment resolutions and/or SAFE-PB cable resolutions. Upon having identified the analysis resolutions and inputting them into SAFE-PB, the analyst re-performs the full area burn analysis (second iteration) for the associated area to demonstrate that at least one train of electrical distribution and mechanical support systems is recovered. In the second and any subsequent iterations of the full area burn analysis, the equipment and/or cables provided with SAFE-PB resolutions for the area (resolutions are area specific) are not blocked as failures, and do not contribute to the failure of any logically associated equipment, systems, and performance goals.

The analyst then reviews the fire area results again to identify least affected safe shutdown paths and their associated systems and equipment, and then identifies the key equipment and cable failures associated with these safe shutdown paths and their associated systems and equipment that must be addressed to demonstrate deterministic compliance. These key failures are further analyzed to determine the true nature of the fire impact, which are then also documented as SAFE-PB equipment resolutions and/or SAFE-PB cable resolutions. Upon having identified the analysis resolutions and inputting them into SAFE-PB, the analyst re-performs the full area burn analysis (third iteration) for the associated fire area to demonstrate that at least one safe shutdown success path is recovered for each performance goal. These iterations continue, as necessary, until Page B-120

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.4 Fire Area Assessment the analyst has successfully demonstrated that at least one safe shutdown success path is recovered for each performance goal.

The text associated with each SAFE-PB equipment resolution may typically include a description of:

(1) the justification for why a specific cable or supporting component failure is non-consequential to the safe shutdown function of the component (i.e., NFPA 805, Section 4.2.3.2),

(2) a proposed recovery action without prior NRC approval (for subsequent analysis using the performance based Risk Evaluation process per NFPA 805, Section 4.2.4),

(3) a credited recovery action with prior NRC approval (for subsequent analysis using the performance based Risk Evaluation process per NFPA 805, Section 4.2.4),

(4) the justification for why the subject equipment is considered to be deterministically compliant based on a prior NRC approval that is being transitioned forward to NFPA 805, (5) a proposed plant modification to achieve deterministic compliance (i.e., NFPA 805, Section 4.2.3.2), or (6) compliance based upon meeting the deterministic separation requirements of NFPA 805, Sections 4.2.3.3 or 4.2.4.4, as applicable.

The text associated with each SAFE-PB cable resolution may typically include a description of:

(1) compliance based upon the deterministic separation requirements of NFPA 805, Sections 4.2.3.3 or 4.2.4.4, as applicable (2) the justification for why the cable is considered to be deterministically compliant based on a prior NRC approval that is being transitioned forward to NFPA 805, or (3) a proposed plant modification to achieve deterministic compliance (i.e., NFPA 805, Section 4.2.3.2).

This process does not require the analyst to address every safe shutdown equipment and/or cable failure in the area. The analyst is only required to address the minimum set of fire affected safe shutdown equipment and/or cable to demonstrate the availability of one safe shutdown success path for each performance goal, based on the possible combinations allowed through logical safe shutdown model in SAFE-PB."

Comments Reference Document Doc, Details FCS Engineering Analysis EA10-036 Section 4.10 Page B-121

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.4 Fire Area Assessment NEI 00-01 Section 3.0 Guidance 3.4.1.4 Criteria/Assumptions Use manual actions where appropriate to achieve and maintain postfire safe shutdown conditions in accordance with NRC requirements.

Applicabilitv Comments Applicable Alignment Statement Aligns Alianment Basis Engineering analysis EA10-036, Section 4.10:

"The text associated with each SAFE-PB equipment resolution may typically include a description of:

(1) the justification for why a specific cable or supporting component failure is non-consequential to the safe shutdown function of the component (i.e., NFPA 805, Section 4.2.3.2),

(2) a proposed recovery action without prior NRC approval (for subsequent analysis using the performance based Risk Evaluation process per NFPA 805, Section 4.2.4),

(3) a credited recovery action with prior NRC approval (for subsequent analysis using the performance based Risk Evaluation process per NFPA 805, Section 4.2.4),

(4) the justification for why the subject equipment is considered to be deterministically compliant based on a prior NRC approval that is being transitioned forward to NFPA 805, (5) a proposed plant modification to achieve deterministic compliance (i.e., NFPA 805, Section 4.2.3.2), or (6) compliance based upon meeting the deterministic separation requirements of NFPA 805, Sections 4.2.3.3 or 4.2.4.4, as applicable.

The text associated with each SAFE-PB cable resolution may typically include a description of:

(1) compliance based upon the deterministic separation requirements of NFPA 805, Sections 4.2.3.3 or 4.2.4.4, as applicable (2) the justification for why the cable is considered to be deterministically compliant based on a prior NRC approval that is being transitioned forward to NFPA 805, or (3) a proposed plant modification to achieve deterministic compliance (i.e., NFPA 805, Section 4.2.3.2)."

Comments Reference Document Doc. Details FCS Engineering Analysis EA10-036 Section 4.10 Page B-122

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.4 Fire Area Assessment NEI 00-01 Re NEI 00-01 Section 3.0 Guidance 3.4.1.5 Criteria/Assumptions Where appropriate to achieve and maintain cold shutdown within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months , use repairs to equipment required in support of post-fire shutdown.

ADDlicabilitv Comments Applicable Alignment Statement Aligns with Intent Aligonment Basis Engineering analysis EAI0-036:

Assumption 4.2.7:

"Appendix R post-fire safe shutdown analysis assumes a 72-hour coping period starting with a reactor scram/trip. Under the NFPA 805 Performance-Based Standard, the nuclear safety goal is to provide reasonable assurance that a fire will not prevent the plant from maintaining the fuel in a safe and stable condition. Consequently, the analysis can demonstrate that the plant can be maintained in hot shutdown until such time that plant systems can be recovered for transition to cold shutdown. Fire-induced impacts that provide no adverse consequences to achieving and maintaining hot shutdown need not be included in the post-fire safe shutdown analysis. At least one train can be repaired or made operable using onsite capability to achieve cold shutdown.

The objective of safe and stable plant operations as defined for the FCS NFPA 805 NSPC analysis is to achieve and maintain Mode 3 (Hot Shutdown Condition) for a 24-hour coping time with the minimum shift operating staff, and to maintain Mode 3 (Hot Shutdown Condition) thereafter as supplemented with the assistance of the FCS Emergency Response Organization, etc. Safe and stable plant operation as defined for the FCS NFPA 805 NSPC analysis does not require the plant to achieve and maintain cold shutdown. However, it is noted that the FCS NFPA 805 NSPC analysis has maintained, from the FCS 10 CFR 50 Appendix R analysis, the analysis of cold shutdown capability, including the transition phase from Mode 3 (Hot Shutdown Condition) to cold shutdown, and the achievement and maintenance of cold shutdown. The fire area strategies for the transition to cold shutdown, and cold shutdown strategies include operator manual actions and repairs as actions to mitigate fire damage, where appropriate. These strategies, inclusive of repairs and operator manual actions, are not identified as Variances from the Deterministic Requirements of NFPA 805 (VFDRs)."

Comments Reference Document Doc, Details FCS Engineering Analysis EA10-036 Assumption 4.2.7 Page B-123

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.4 Fire Area Assessment NEI 00-01 Ref NEI 00-01 Section 3.0 Guidance 3.4.1.6 Criteria/Assumptions Appendix R compliance requires that one train of systems necessary to achieve and maintain hot shutdown conditions from either the control room or emergency control station(s) is free of fire damage (III.G.l.a). When cables or equipment, including associated circuits, are within the same fire area outside primary containment and separation does not already exist, provide one of the following means of separation for the required safe shutdown path(s):

- Separation of cables and equipment and associated nonsafety circuits of redundant trains within the same fire area by a fire barrier having a 3-hour rating (IllI.G.2.a)

- Separation of cables and equipment and associated nonsafety circuits of redundant trains within the same fire area by a horizontal distance of more than 20 feet with no intervening combustibles or fire hazards. In addition, fire detectors and an automatic fire suppression system shall be installed in the fire area (IlI.G.2.b).

- Enclosure of cable and equipment and associated non-safety circuits of one redundant train within a fire area in a fire barrier having a one-hour rating. In addition, fire detectors and an automatic fire suppression system shall be installed in the fire area (IIl.G.2.c).

For fire areas inside noninerted containments, the following additional options are also available:

- Separation of cables and equipment and associated nonsafety circuits of redundant trains by a horizontal distance of more than 20 feet with no intervening combustibles or fire hazards (lll.G.2.d);

- Installation of fire detectors and an automatic fire suppression system in the fire area (lII.G.2.e); or

- Separation of cables and equipment and associated non-safety circuits of redundant trains by a noncombustible radiant energy shield (IIl.G.2.f).

Use exemptions, deviations and licensing change processes to satisfy the requirements mentioned above and to demonstrate equivalency depending upon the plant's license requirements.

ADlicabilit Comments Applicable Alignment Statement Aligns Alianment Basis Engineering analysis EA10-036, Definition 4.3.3:

Page B-124

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.4 Fire Area Assessment "Deterministic Compliance - The deterministic compliance requirements of NFPA 805 Chapter 4 follow:

"4.2.3 Deterministic Approach. This section shall provide deterministic methods to meet the nuclear safety performance criteria described in Section 1.5.

4.2.3.1 One success path of required cables and equipment to achieve and maintain the nuclear safety performance criteria without the use of recovery actions shall be protected by the requirements specified in either 4.2.3.2, 4.2.3.3, or 4.2.3.4, as applicable. Use of recovery actions to demonstrate availability of a success path for the nuclear safety performance criteria automatically shall imply use of the performance-based approach as outlined in 4.2.4.

4.2.3.2 One success path of required cables and equipment shall be located in a separate area having boundaries consisting of fire barriers with a minimum fire resistance rating of 3 hours3.472222e-5 days 8.333333e-4 hours 4.960317e-6 weeks 1.1415e-6 months . Every opening in the fire barriers forming these boundaries shall be protected with passive fire protection features having a fire-resistive rating equivalent to the fire barrier. Exception: Fire resistance rating, if any, of exterior walls shall be determined by a fire hazard analysis.

4.2.3.3 Where required cables or equipment of redundant success paths of systems necessary to achieve and maintain the nuclear safety performance criteria are located within the same fire area outside of primary containment, one of the following means of ensuring that at least one success path is free of fire damage shall be provided.

1. Separation of required cables and equipment of redundant success paths by a fire barrier having a 3-hour fire resistance rating. Enclosure of cable and equipment and associated non-safety circuits of a redundant success path in a fire barrier or ERFBS having a 3-hour fire resistance rating.

2. Separation of required cables and equipment of redundant success paths by a horizontal distance of more than 20 ft (6.1 m) with no intervening combustible materials or fire hazards. In addition, automatic fire detectors and an automatic fire suppression system shall be installed throughout the fire area.

3. Enclosure of cable and equipment and associated nonsafety circuits of one redundant success path in a fire barrier or ERFBS having a 1-hour fire resistance rating. In addition, automatic fire detectors and an automatic fire suppression system shall be installed throughout the fire area.

4.2.3.4 Inside non-inerted containments one of the fire protection means specified in 4.2.3.3 or one of the following fire protection means shall be provided:

1. Separation of required cables and equipment of redundant success paths by a horizontal distance of more than 20 ft (6.1 m) with no intervening combustibles or fire hazards.

2. Separation of required cables and equipment of redundant success paths by a noncombustible radiant energy shield. These assemblies shall be capable of withstanding a minimum 1/2-hour fire exposure when tested in accordance with NFPA 251, Standard Methods of Tests of Fire Endurance of Building Construction and Materials.

3. Installation of automatic fire detectors and an automatic fire suppression system throughout the fire area.""

Comments Reference Document Doc. Details FCS Engineering Analysis EA10-036 Definition 4.3.3 Page B- 125

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.4 Fire Area Assessment NEI 00-01 Ref NEI 00-01 Section 3.0 Guidance 3.4.1.7 Criteria/Assumptions Consider selecting other equipment that can perform the same safe shutdown function as the impacted equipment. In addressing this situation, each equipment impact, including spurious operations, is to be addressed in accordance with regulatory requirements and the NPP's current licensing basis.

A2olicabilio Comments Applicable Alignment Statement Aligns with Intent Alignment Basis Engineering analysis EA10-036, Attachments 1 and 5: of EA10-036 provides a written description of the FCS NFPA 805 NSPC performance goals, systems, and equipment that constitute the NFPA 805 NSPC model.

The attachment also identifies the plant equipment that has been modeled based on the potential for adverse impact to safe and stable plant operation resulting from one or more spurious operation. The selection of FCS plant systems and equipment was developed with input from plant emergency operating procedures EOP-00 and EOP-20 to obtain a reasonable balance between the number of potential success paths and the overall complexity of the model. of EA10-036 includes logic diagrams that represent the FCS NFPA 805 NSPC performance goals, systems, and equipment that constitute the NFPA 805 NSPC model.

Reference Document Doc. Details FCS Engineering Analysis EA10-036 Attachments 1 and 5 FCS Emergency Operating Procedure EOP-00 FCS Emergency Operating Procedure EOP-20 Page B-126

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.4 Fire Area Assessment NEI 00-01 Ref NEI 00-01 Section 3.0 Guidance 3.4.1.8 Criteria/Assumptions Consider the effects of the fire on the density of the fluid in instrument tubing and any subsequent effects on instrument readings or signals associated with the protected safe shutdown path in evaluating postfire safe shutdown capability. This can be done systematically or via procedures such as Emergency Operating Procedures.

Aglicabilit Applicable Alignment Statement Aligns Alignment Basis Engineering analysis EA10-036, Attachment 10, Section 1.0:

"This analysis has been performed to address the potential adverse impact from fire exposure to instrument tubing sense lines for process instruments which are required to support the NFPA 805 NSPC.

The heating of instrument tubing sense lines from fire exposure has been postulated to cause erratic or erroneous signals from the associated process instrument.

Consistent with NFPA 805, 2001 Edition, Section B.2.1.(e) and NEI 00-01, Revision 2, Section 3.2.1.2, fire exposure to instrument tubing sense lines has also been postulated to cause failure of the associated pressure boundary for instrument tubing sense lines that are constructed with heat sensitive brazed or soldered connections.

The following discussion addresses the adequacy of instrument sensing lines for support of the deterministic NFPA 805 Nuclear Safety Performance Criteria (NSPC) Safe Shutdown Analysis (SSA). This evaluation covers the sensing line from the point where it "taps" into the process to the transmitter. The remainder of the instrument loop is covered by the NFPA 805 NSPC cable analysis. This will ensure that process monitoring instrumentation credited for NFPA 805 safe shutdown will be available to provide operations personnel with the necessary indications during safe shutdown, and that potentially adverse spurious instrument signals resulting from fire exposure to instrument sensing lines is adequately considered in the NFPA 805 NSPC SSA, as applicable. This applies to both safe shutdown performed from within and from outside the Main Control Room."

Comments Reference Document Doc. Details FCS Engineering Analysis EA10-036 Attachment 10, Section 1.0 Page B-127

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.4 Fire Area Assessment NEI 00-01 Re NEI 00-01 Section 3.0 Guidance 3.4.2 Methodology for Fire Area Refer to Figure 3-5 for a flowchart illustrating the various steps involved in performing a fire area assessment.

Assessment Use the following methodology to assess the impact to safe shutdown and demonstrate Appendix R compliance:

AR12licabilit Comments Applicable Alignment Statement Not Required Alignment Basis Generic paragraph. Detailed alignment discussed in subsequent reference paragraphs.

Comments Reference Document Page B-128

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.4 Fire Area Assessment NEI 00-01 Ref NEI 00-01 Section 3.0 Guidance 3.4.2.1 Identify the Affected Identify the safe shutdown cables, equipment and systems located in each fire area that may be potentially damaged by the fire.

Equipment by Fire Area Provide this information in a report format. The report may be sorted by fire area and by system in order to understand the impact to each safe shutdown path within each fire area (see Attachment 5 for an example of an Affected Equipment Report).

ARDlicabili Comments Applicable Alignment Statement Aligns Alignment Basis Engineering analysis EA10-036, Section 4.10:

Engineering analysis EA10-036, Attachment 12 (the procedure for review and update of the fire area assessment) describes the guidelines utilized to perform the automated deterministic fire area analysis using SAFE-PB software tool.

"The analysis is typically performed through an iterative process, with each iteration postulating a full area burn fire in the associated plant fire area. The analyst is to initially assume that all of the fire affected equipment in the fire area fails to the worst case position or status. In the initial iteration, the full area burn fails all of the safe shutdown cables and equipment located within the analyzed area. Consequently, other safe shutdown equipment also fail based on the logical associations to the directly fire affected equipment and cables, which in turn may fail other equipment, systems, and performance goals in the safe shutdown model. The safe shutdown model includes plant components whose fire induced spurious operation, alone, or in combination, could be adverse to one or more success paths associated with each performance goal, as applicable. As a result of the initial full area burn analysis in SAFE-PB, the analyst is provided with all of the potentially fire affected safe shutdown paths, systems, equipment, and cables in the analyzed fire area."

Engineering analysis EA10-036, Attachment 8:

Engineering analysis EA10-036, Attachment 8, "Compliance Strategy by Fire Area" documents the NFPA 805 NSPC compliance strategy for each fire area. This attachment includes the SAFE-PB equipment and cable resolutions, where applicable, that identify the justification or mitigating actions proposed for achieving safe shutdown. An overall summary of the NFPA 805 NSPC compliance strategy is also provided in Attachment 8 for each fire area. The attachment also includes the SAFE-PB output reports for each fire area, inclusive of the final iteration full area burn. This includes a listing of all safe shutdown equipment and cables in each fire area.

Comments Reference Document Doc. Details FCS Engineering Analysis EA10-036 Section 4.10 Attachment 8 Page B-129

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.4 Fire Area Assessment NEI 00-01 Ref NEI 00-01 Section 3.0 Guidance 3.42.2 Determine the Shutdown Based on a review of the systems, equipment and cables within each fire area, determine which shutdown paths are either unaffected Paths Least Impacted By a or least impacted by a postulated fire within the fire area. Typically, the safe shutdown path with the least number of cables and Fire in Each Fire Area equipment in the fire area would be selected as the required safe shutdown path. Consider the circuit failure criteria and the possible mitigating strategies, however, in selecting the required safe shutdown path in a particular fire area. Review support systems as a part of this assessment since their availability will be important to the ability to achieve and maintain safe shutdown. For example, impacts to the electric power distribution system for a particular safe shutdown path could present a major impediment to using a particular path for safe shutdown. By identifying this early in the assessment process, an unnecessary amount of time is not spent assessing impacts to the frontline systems that will require this power to support their operation.

Based on an assessment as described above, designate the required safe shutdown path(s) for the fire area. Identify all equipment not in the safe shutdown path whose spurious operation or mal-operation could affect the shutdown function. Include these cables in the shutdown function list. For each of the safe shutdown cables (located in the fire area) that are part of the required safe shutdown path in the fire area, perform an evaluation to determine the impact of a fire-induced cable failure on the corresponding safe shutdown equipment and, ultimately, on the required safe shutdown path.

When evaluating the safe shutdown mode for a particular piece of equipment, it is important to consider the equipment's position for the specific safe shutdown scenario for the full duration of the shutdown scenario. It is possible for a piece of equipment to be in two different states depending on the shutdown scenario or the stage of shutdown within a particular shutdown scenario. Document information related to the normal and shutdown positions of equipment on the safe shutdown equipment list.

Aomlicabillit Comments Applicable Alignment Statement Aligns Aligunment Basis Engineering analysis EA10-036, Section 4.10:

Engineering analysis EA10-036, Attachment 12 (the procedure for review and update of the fire area assessment) describes the guidelines utilized to perform the automated deterministic fire area analysis using SAFE-PB software tool.

"The analysis is typically performed through an iterative process, with each iteration postulating a full area burn fire in the associated plant fire area. The analyst is to initially assume that all of the fire affected equipment in the fire area fails to the worst case position or status. In the initial iteration, the full area burn fails all of the safe shutdown cables and equipment located within the analyzed area. Consequently, other safe shutdown equipment also fail based on the logical associations to the directly fire affected equipment and cables, which in turn may fail other equipment, systems, and performance goals in the safe shutdown model. The safe shutdown model includes plant components whose fire induced spurious operation, alone, or in combination, could be adverse to one or more success paths associated with each performance goal, as applicable. As a result of the initial full area burn analysis in SAFE-PB, the analyst is provided with all of the potentially fire affected safe shutdown paths, systems, equipment, and cables in the analyzed Page B-130

Omaha Public Power District FCS NFPA 805 Transition Report Table B-2 Nuclear Safety Capability Assessment Methodology Review NFPA 805 Section: 2.4.2.4 Fire Area Assessment fire area.

To resolve the deterministic analysis for each fire area, the analyst first reviews the initial area results to determine the least affected electrical distribution and mechanical support systems, and then identifies the key equipment and cable failures associated with these electrical distribution and mechanical support systems that must be addressed to recover a least one train of these systems. These key failures are further analyzed to determine the true nature of the fire impact, which are then documented as SAFE-PB equipment resolutions and/or SAFE-PB cable resolutions. Upon having identified the analysis resolutions and inputting them into SAFE-PB, the analyst re-performs the full area burn analysis (second iteration) for the associated area to demonstrate that at least one train of electrical distribution and mechanical support systems is recovered. In the second and any subsequent iterations of the full area burn analysis, the equipment and/or cables provided with SAFE-PB resolutions for the area (resolutions are area specific) are not blocked as failures, and do not contribute to the failure of any logically associated equipment, systems, and performance goals.

The analyst then reviews the fire area results again to identify least affected safe shutdown paths and their associated systems and equipment, and then identifies the key equipment and cable failures associated with these safe shutdown paths and their associated systems and equipment that must be addressed to demonstrate deterministic compliance. These key failures are further analyzed to determine the true nature of the fire impact, which are then also documented as SAFE-PB equipment resolutions and/or SAFE-PB cable resolutions. Upon having identified the analysis resolutions and inputting them into SAFE-PB, the analyst re-performs the full area burn analysis (third iteration) for the associated fire area to demonstrate that at least one safe shutdown success path is recovered for each performance goal. These iterations continue, as necessary, until the analyst has successfully demonstrated that at least one safe shutdown success path is recovered for each performance goal.