FirePRA - User contributions [en]

Fire PRA Documentation (Task 16)

2017-07-15T06:59:39Z

144.58.50.174:

==Task Overview==

===Background===
This provides suggestions for documenting a Fire PRA.

===Purpose===
This procedure provides the general practice considered necessary for documenting the Fire PRA and its results.

===Scope===
This procedure covers the recommended documentation of the Fire PRA, including coverage of all the major tasks of the Fire PRA, as outlined in this document.

==Related Element(s) of ASME/ANS PRA Standard, ASME-RA-Sb-2013==

==Related NUREG/CR-6850 Appendices:==

==Supplemental Guidance==

Uncertainty and Sensitivity Analyses (Task 15)

2017-07-15T06:58:32Z

144.58.50.174:

==Task Overview==

===Background===
This task describes the approach to follow for identifying and treating uncertainties throughout the Fire PRA process. The treatment may vary from quantitative estimation and propagation of uncertainties where possible (e.g., in fire frequency and non-suppression probability) to identification of sources without quantitative estimation, where knowledge of a quantitative treatment of uncertainties is beyond the state-of-the-art. The treatment may also include one-at-a-time variation of individual parameter values to determine the effect on the overall fire risk (sensitivity analysis).

===Purpose===
This procedure describes the approach for identifying and treating uncertainties throughout the Fire PRA process and identifying sensitivity analysis cases. It also prescribes a review for the identified uncertainties among the Fire PRA analysts to establish an integrated approach of addressing the effects of these uncertainties on the results of the analysis. At this time, the procedure provides a general approach to be followed and does not provide a comprehensive list of specific uncertainties to be addressed. As pilot Fire PRAs and other studies are completed, this procedure may be revised accordingly.

===Scope===
This procedure covers the identification and treatment of uncertainties throughout the Fire PRA. As such, it provides: (1) background on the subject of uncertainty found in Appendix U, (2) classification of types of uncertainty, and (3) a general approach with regard to practical implementation of treating expected uncertainties in the Fire PRA, as described in Appendix V.

==Related Element(s) of ASME/ANS PRA Standard, ASME-RA-Sb-2013==

==Related NUREG/CR-6850 Appendices:==

==Supplemental Guidance==

Fire Risk Quantification (Task 14)

2017-07-15T06:56:58Z

144.58.50.174:

==Task Overview==

===Background===
The task description provides recommendations for quantification and presentation of fire risk results.

===Purpose===
This section describes the procedure for performing fire risk quantification. This procedure provides the user a general method for quantifying the final Fire PRA Model to generate the final fire risk results.

===Scope===
This procedure addresses the following major steps for each of the major fire risk quantification tasks:

* Step 1–Quantify Final Fire CDF Model
* Step 2–Quantify Final Fire LERF Model
* Step 3–Conduct Uncertainty Analysis

In this task, the final Fire PRA model is quantified to obtain the final fire risk results. The final CDF and LERF models are quantified for each fire scenario.

Note that per Task 7, Quantitative Screening, it is expected that a number of fire compartments or fire scenarios will be screened out from the formal fire quantification results (i.e., not added into the calculated total plant fire-related CDF and LERF). It is expected that as a minimum, total plant CDF and LERF estimates will be provided by summing all the CDFs and LERFs for the unscreened fire compartments/scenarios. The significant contributors to the plant CDF and LERF should also be provided. In addition, it is also expected that the nature (e.g., type of sequences) of the screened out compartments/scenarios are at least identified and as a check of the cumulative screening criteria discussed in Task 7, it is recommended that the screened CDFs and LERFs also be summed separately to provide a perspective on the total residual risk from the screened compartments/scenarios. It should be emphasized that these screened portions of the results represent various levels of analysis (for instance, some may only involve fire scoping modeling; others may involve both detailed fire modeling and some detailed circuit analysis, etc.). Thus any ranking of these screened scenarios is not particularly appropriate and these screened summations of CDF/LERF are upper bounds of the residual risk and that in actuality, the residual risk is probably much less than these sums would indicate.

==Related Element(s) of ASME/ANS PRA Standard, ASME-RA-Sb-2013==

==Related NUREG/CR-6850 Appendices:==

==Supplemental Guidance==

Seismic Fire Interactions (Task 13)

2017-07-15T06:54:59Z

144.58.50.174:

==Task Overview==

===Background===
This task is a qualitative approach to help identify the risk from any potential interactions between an earthquake and fire.

===Purpose===
The Fire Risk Scoping Study [13.1] identified the following four seismic-fire interaction issues:

* 1.8. Seismically induced fires
* 2.9. Degradation of fire suppression systems and features
* 3.10. Spurious actuation of suppression and/or detection systems
* 4.11. Degradation of manual firefighting effectiveness

It is recommended that a Fire PRA include a qualitative assessment of these issues. In this procedure, a recommended approach is given.

This procedure does not provide a methodology for developing models and quantifying risk associated with fires caused by a severe seismic event. This is due to a combination of limitations in the state of the art, and the perceived low level of risk from these fires. The low risk is based on the low frequency of an earthquake that can initiate a challenging fire and degrade various plant fire protection defense-in-depth elements, and the general seismic ruggedness of the NPPs as part of their design basis. This procedure outlines a series of steps intended to verify this premise. If the verification steps outlined in this procedure do not preclude the risk significance, either a quantitative assessment or consideration of physical or procedural changes may follow.

===Scope===
Consistent with the recommendations of Reference [13.1] and those outlined in the EPRI FIVE [13.2] and Fire PRA Implementation Guide [13.3], recommended practice in the seismic fire interactions assessment utilizes a qualitative, walkdown-based approach, rather than quantitative methods to estimated associated risk. This task provides a stand-alone study of the effects of a fire due to an earthquake. This task is not intended to develop quantitative estimates of the risk associated with seismic-fire interactions.
==Related Element(s) of ASME/ANS PRA Standard, ASME-RA-Sb-2013==

==Related NUREG/CR-6850 Appendices:==

==Supplemental Guidance==

Post-Fire Human Reliability Analysis (Task 12)

2017-07-15T06:52:28Z

144.58.50.174:

==Task Overview==

===Background===
This task considers operator actions for manipulation of plant components. The analysis task procedure provides structured instructions for identification and inclusion of these actions in the Fire PRA. The procedure also provides instructions for estimating screening human error probabilities (HEPs) before detailed fire modeling results (e.g., fire growth and damage behaviors) have been developed. Estimating HEP values with high confidence is critical to the effectiveness of screening in a Fire PRA. This report does not develop a detailed fire HRA methodology. There are a number of HRA methods that can be adopted for fire with appropriate additional instructions that superimpose fire effects on any of the existing HRA methods, such as SHARP, ATHEANA, etc. This would improve consistency across analyses i.e., fire and internal events PRA.

===Purpose===
This document describes the procedure for evaluating the impact of fire scenarios on the human actions addressed in the base PRA study (i.e., the Internal Events PRA or original Fire IPEEE analysis) used to create the Fire PRA Model, as well as how to identify and quantify new actions to be performed as part of the plant fire mitigation plans and procedures. Evaluating the reliability for these human actions supports the Fire PRA Model for calculating such metrics as CDF, CCDP, LERF, and CLERP for fire-induced initiating events. The initial quantification of these metrics makes use of screening probabilities for human failure events (HFEs) where appropriate. As necessary, more detailed best estimate analyses of some human actions will be needed to obtain more realistic assessments of fire risk.

===Scope===
Task 12 addresses a process for performing both screening and detailed analysis of post-fire human actions identified in accident sequences initiated by a fire. The main focus is to foster the process for assessing the impact of location-specific fires on the human actions taken in response to a fire-induced initiating event, thus preventing core damage and mitigating releases. This task procedure covers three essential elements of most human reliability analysis (HRA) studies.

* Identification of the HFEs to be included in the Fire PRA.
* The assignment of screening human error probabilities for the identified HFEs to assist in focusing the modeling and fire risk analysis to those scenarios and human actions most important to the overall risk results.
* Considerations for the detailed best-estimate quantification of the more important HFEs to properly consider the fire effects on human performance.

In covering the above scope, it is important to stress that this procedure focuses on those unique fire considerations that need to be included in performing a HRA for the Fire PRA using whatever method (e.g., ASEP [12.1], etc.) is chosen by the analyst. It is therefore equally important to stress what this procedure does not do. This procedure is not a handbook or a similar stand-alone manual for doing a Fire HRA, in that it does not attempt to duplicate all the typical activities in carrying out a HRA like that specified by the ASME Standard ASME-RA-S2002 [12.2]. Nor does this procedure attempt to provide a new or particularly prescriptive method for assessing the HEPs in a Fire PRA, since introducing such a method would be a research project far beyond the intended boundaries and resources for producing these fire procedures. Use of this procedure and the unique fire-related considerations that it covers is expected to be used in concert with already-available HRA techniques and calculation tools by an experienced HRA analyst(s) to perform a defensible and realistic HRA for a Fire PRA.

Notably, the scope of this procedure does not include pre-initiator human failure events specifically related to fire systems, barriers, or programs. Undetected pre-initiator human failures such as improperly restoring fire suppression equipment after test, compromising a fire barrier, or incorrectly storing a transient combustible can all affect the fire risk. Tasks 6, 8, and 11 make use of industry-wide data that within it contains contributions from such human failures. Hence to that extent, these pre-initiator failures are treated within the Fire PRA. Nevertheless, no specific steps are provided here for performing a plant-specific review of the potential for such human failures and thus influencing the use of the industry-wide data. This does not preclude the expectation that pre-initiator human failure events from the Internal Events PRA (i.e., not specifically related to fires) should remain in the Fire PRA Model covering their contribution to component unavailability for safe shutdown systems within the PRA model structure.

==Related Element(s) of ASME/ANS PRA Standard, ASME-RA-Sb-2013==

==Related NUREG/CR-6850 Appendices:==

==Supplemental Guidance==

Detailed Fire Modeling (Task 11)

2017-07-15T06:50:24Z

144.58.50.174:

==Task Overview==

===Background===
This task describes the method to examine the consequences of a fire. This includes consideration of scenarios involving single compartments, multiple fire compartments, and the main control room. Factors considered include initial fire characteristics, fire growth in a fire compartment or across fire compartments, detection and suppression, electrical raceway fire barrier systems, and damage from heat and smoke. Special consideration is given to turbine generator (T/G) fires, hydrogen fires, high-energy arcing faults, cable fires, and main control board (MCB) fires. There are considerable improvements in the method for this task over the EPRI FIVE and Fire PRA Implementation Guide in nearly all technical areas.

===Purpose===
In the preceding tasks, the analyses were organized around compartments, assuming that a fire would have widespread impact within the compartment. In Task 11, for those compartments found to be potentially risk-significant (i.e., unscreened compartments), a detailed analysis approach is provided. As part of the detailed analysis, fire growth and propagation is modeled and possibility of fire suppression before damage to a specific target set is analyzed.

The detailed fire modeling process generally follows a common step structure, but the details of the analyses often vary depending on the specifics of the postulated fire scenario. This chapter provides separate procedures for three general categories of fire scenarios: fires affecting target sets located inside one compartment (discussed in Section 11.5.1); fires affecting the main control room (MCR; Section 11.5.2); and fires affecting target sets located in more than one fire compartment (multicompartment fire analysis; Section 11.5.3).

Task 11 provides final estimates for the frequency of occurrence of fire scenarios involving a specific fire ignition source failing a predefined target set before fire protection succeeds in protecting the target set. This result is combined in the final quantification steps that follow this task, with the CCDP/CLERP given failure of the target set to estimate the CDF/LERF contribution for each fire scenario. The CCDP/CLERP may include modified human error probabilities based on fire scenario specifics

===Scope===
Detailed fire modeling encompasses an analysis of the physical fire behavior (i.e., fire growth and propagation analysis), equipment damage, fire detection, and fire suppression. The fire scenarios to analyze as part of this detailed analysis task are divided into three categories:

* ''General single compartment fire scenarios''. This general category covers fire scenarios damaging target sets located within the same compartment, exclusive of those scenarios within or impacting the MCR. In general, in this category, the fire ignition source is in the same compartment as the target set. The majority of fire scenarios analyzed generally falls into this category. The procedures applicable to the analysis of these fire scenarios are presented in Section 11.5.1.
* ''MCR fire scenarios''. This general category covers all fires that occur within the MCR. This category also covers scenarios involving fires in compartments other than the MCR that may force MCR abandonment. The MCR analysis procedures are presented in Section 11.5.2.
* ''Multicompartment fire scenarios'': This general category covers all fire scenarios where it is postulated that a fire may spread from one compartment to another and damage target elements in multiple compartments. In this category of scenarios, damaging effects of a fire (e.g., heat) are assumed to spread beyond the compartment of fire origin. The multicompartment fire analysis procedures are presented in Section 11.5.3.

A detailed fire modeling analysis is performed for each fire scenario in each unscreened fire compartment. For many compartments, it may be appropriate to develop several fire scenarios to appropriately represent the range of unscreened fire ignition sources (i.e., scenarios that would not screen out in Task 8) that might contribute to the fire risk. Detailed fire modeling may utilize a range of tools to assess fire growth and damage behavior, and the fire detection and suppression response, for specific fire scenarios.

The ultimate output of Task 11 is a set of fire scenarios, frequency of occurrence of those scenarios, and a list of target sets (in terms of fire PRA components) associated with the scenarios. For scenarios involving the MCR, the possibility of forced abandonment is also noted. Note that a fire scenario represents a specific chain of events starting with ignition of a fire ignition source, propagation of the fire effects to other items, and possibility of damaging a set of items identified as target set before successful fire suppression.

==Related Element(s) of ASME/ANS PRA Standard, ASME-RA-Sb-2013==

==Related NUREG/CR-6850 Appendices:==

==Supplemental Guidance==

Circuit Failure Mode Likelihood Analysis (Task 10)

2017-07-15T06:47:13Z

144.58.50.174:

==Task Overview==

===Background===
This task considers the relative likelihood of various circuit failure modes. This added level of resolution may be a desired option for those fire scenarios that are significant contributors to the risk. The methodology provided in this document benefits from the knowledge gained from the tests performed in response to the circuit failure issue.

===Purpose===
Conducting a Fire PRA in accordance with this methodology necessitates an analysis of fireinduced circuit failures beyond that typically conducted during original Fire PRAs. The circuit analysis elements of the project are conducted in three distinct phases:

# Fire PRA cable selection (Task 3),
# Detailed circuit failure analysis (Task 9), and
# Circuit failure mode likelihood analysis (Task 10).

This task provides methods and instructions for conducting the third phase of circuit analysis – circuit failure mode likelihood analysis for Fire PRA cables. Task 10 estimates the probability of hot short cable failure modes of interest, which in turn can be correlated to specific component failure modes. As discussed in Section 3.3.2 of Volume 1, the methods and techniques for deriving circuit failure mode probability estimates are based on limited data and experience. Consequently, this area of analysis is not yet a mature technology, and undoubtedly further advances and refinements will come with time. Nonetheless, the methods and techniques presented in this chapter represent the current state of knowledge and provide a reasonable approach for establishing first-order circuit failure mode probability estimates, albeit with relatively high uncertainty tolerances.

===Scope===
Chapter 10 provides methods and technical considerations for assigning probability estimates to specific cable failure modes associated with fire-induced cable damage.

This task does not address the implementation of plant-specific quality assurance or configuration control requirements that might apply to a Fire PRA. Nor is it intended to validate the accuracy of plant-specific data extracted from plant drawings, documents, or databases. Each plant should follow appropriate quality assurance, administrative, and configuration control procedures applicable to the work being conducted. The need to validate input source documents should be addressed as part of assembling the prerequisite information in Step 1.

==Related Element(s) of ASME/ANS PRA Standard, ASME-RA-Sb-2013==

==Related NUREG/CR-6850 Appendices:==

==Supplemental Guidance==

Detailed Circuit Failure Analysis (Task 9)

2017-07-15T06:44:55Z

144.58.50.174:

==Task Overview==

===Background===
This task provides an approach and technical considerations for identifying how the failure of specific cables will impact the components included in the Fire PRA SSD plant response model.

===Purpose===
Conducting a Fire PRA in accordance with this methodology necessitates an analysis of fireinduced circuit failures beyond that typically conducted during original Fire PRAs. The circuit analysis elements of the project are conducted in three distinct phases:

# Fire PRA cable selection (Task 3)
# Detailed circuit failure analysis (Task 9), and
# Circuit failure mode likelihood analysis (Task 10).

This chapter provides methods and instructions for conducting the second phase of circuit analysis–detailed circuit failure analysis (Task 9). The purpose of Task 9 is to conduct a more detailed analysis of circuit operation and functionality to determine equipment responses to specific cable failure modes. These relationships are then used to further refine the original cable selection by screening out cables that cannot prevent a component from completing its credited function. The output of this task supports the quantitative screening process under Task 7.

As discussed in Chapter 3, in most cases it is advantageous to perform some aspects of Task 9 along with the basic cable selection process of Chapter 3. Analysts are encouraged to screen out early in the cable selection/analysis process those cables that are readily identifiable as not posing a risk to the credited PRA function. A full and complete detailed circuit failure analysis can be time consuming and resource intensive. Accordingly, this level of analysis should be reserved for cases in which the quantitative screening demonstrates a clear need and advantage to fully developing a circuit’s failure modes and response to fire-induced cable failures. Ultimately, each plant will need to find the most efficient balance point with respect to how much detailed circuit analysis is conducted coincident with the cable section.

===Scope===
Chapter 9 provides methods and technical considerations for identifying the potential response of circuits and equipment to specific cable failure modes associated with fire-induced cable damage. This task contains the following key elements:

* Determine the component response to postulated conductor/cable failure modes, and
* Screen out cables that do not impact the ability of a component to complete its credited function.

This task does not address implementation of plant-specific quality assurance and configuration control requirements that might apply to a Fire PRA. Nor is it intended that this procedure validate the accuracy of plant-specific data extracted from plant drawings, documents, or databases. Each plant should follow appropriate quality assurance, administrative, and configuration control procedures applicable to the work being conducted. The need to validate input source documents should be addressed as part of assembling the prerequisite information in Step 1.

==Related Element(s) of ASME/ANS PRA Standard, ASME-RA-Sb-2013==

==Related NUREG/CR-6850 Appendices:==

==Supplemental Guidance==

Scoping Fire Modeling (Task 8)

2017-07-15T06:41:56Z

144.58.50.174:

==Task Overview==

===Background===
This step provides simple rules to define and screen fire ignition sources (and therefore fire scenarios) in an unscreened fire compartment.

===Purpose===
This task has two main objectives:

* To screen out those fixed ignition sources that do not pose a threat to the targets within a specific fire compartment, and
* To assign severity factors to unscreened fixed ignition sources.

It must be noted that only those ignition sources should be considered in this task that were included in establishing the fire ignition frequency in Task 6. All other potential ignition sources that were screened out in Task 6 should neither be addressed in this task. With this task, the level of effort for detailed fire propagation analysis may be reduced. Furthermore, applying severity factors may reduce the compartment frequency calculated in Task 6, resulting in some compartments being screened before detail fire modeling studies are conducted.

===Scope===
This procedure contains instructions for identifying and screening fixed ignition sources. The procedure also provides some general notes on how to assign severity factor values for ignition sources included in the generic fire frequency model.

The procedure recommends two work forms: (1) the walkdown screening form, and (2) the zone of influence (ZOI) form. The walkdown screening form should be filled during the walkdown. It compiles information about the ignition sources relative to nearby equipment. The ZOI form specifies a zone of influence for ignition sources in a specific compartment.

The focus of this task is twofold.

# Refine the information about fixed ignition sources. The direct fire effects on fire PRA components or circuits are not addressed. The basic assumption about loss of all fire PRA components (including cables) present in the fire compartment is still maintained in this task. That is, no equipment in the fire PRA component list is screened. Therefore, the location and specific characteristics of the cables carrying fire PRA component-related circuits are not needed for performing this task.
# Application of severity factors to each ignition source. After applying the severity factor, the compartment fire frequencies calculated in Task 6 are reevaluated.

==Related Element(s) of ASME/ANS PRA Standard, ASME-RA-Sb-2013==

==Related NUREG/CR-6850 Appendices:==

==Supplemental Guidance==

Quantitative Screening (Task 7)

2017-07-15T06:38:59Z

144.58.50.174:

==Task Overview==

===Background===
A Fire PRA allows the screening of fire compartments and scenarios based on their contribution to fire risk. This approach considers the cumulative risk associated with the screened compartments (i.e., the ones not retained for detailed analysis) to ensure that a true estimate of fire risk profile (as opposed to vulnerability) is obtained.

===Purpose===
This section describes the procedure for performing the following quantitative screening tasks:

* Task 7A–Quantitative Screening I
* Task 7B–Quantitative Screening II
* Task 7C–Quantitative Screening III (Optional)
* Task 7D–Quantitative Screening IV (Optional)

This procedure provides the user an approach to quantify the Fire PRA Model using the procedure provided in Task 5, and to screen out fire compartments based on quantitative criteria. This procedure develops the bases for the quantitative screening criteria and provides specific methods for implementing the screening process.

===Scope===
This procedure addresses the following steps for each of the major quantitative screening tasks.

* Step 1–Quantify CDF Model
* Step 2–Quantify LERF Model
* Step 3–Quantitative Screening

In Tasks 7A and 7B, the Fire PRA Model is quantified at the fire compartment level. In Tasks 7C and 7D, the Fire PRA Model is quantified at the fire scenario level. Although not recommended, the quantitative screening can be implemented for screening fire scenarios. Therefore, Tasks 7C and 7D are considered optional tasks in this procedure. The basis for the quantitative screening criteria is developed and an approach for implementing the screening process is provided. To address future use of the Fire PRA Model for risk-informed applications, quantitative screening criteria also consider the impact of equipment unavailability.

==Related Element(s) of ASME/ANS PRA Standard, ASME-RA-Sb-2013==

==Related NUREG/CR-6850 Appendices:==

==Supplemental Guidance==

Fire Ignition Frequency (Task 6)

2017-07-15T06:36:20Z

144.58.50.174:

==Task Overview==

===Background===
This task describes the approach to develop frequency estimates for fire compartments and scenarios. Significant changes from the EPRI FIVE method have been made in this task. The changes generally relate to use of challenging events, considerations associated with data quality, and increased use of a fully component based ignition frequency model (as opposed to the location/component-based model used, for example, in FIVE).

===Purpose===
This section describes the procedure for estimating the fire-ignition frequencies associated with fire ignition sources. Generic ignition frequencies that can be specialized to plant conditions in terms of plant characteristics and plant fire event experience are provided. Uncertainties in the generic frequencies are also provided in terms of 5th, 50th, and 95th percentiles.

===Scope===
This work package addresses the following fire-ignition frequency related issues:

* Plant specific fire event data review and generic fire frequency update using Bayesian approach,
* Equipment (ignition source) count by compartment,
* Apportioning of ignition frequencies according to compartment-specific configurations, and
* Uncertainty considerations in the fire frequencies.

==Related Element(s) of ASME/ANS PRA Standard, ASME-RA-Sb-2013==

==Related NUREG/CR-6850 Appendices:==

==Supplemental Guidance==

Plant Fire-Induced Risk Model (Task 5)

2017-07-15T06:34:31Z

144.58.50.174:

==Task Overview==
===Background===
This task discusses steps for the development of a logic model that reflects plant response following a fire. Specific instructions have been provided for treatment of fire-specific procedures or preplans. These procedures may impact availability of functions and components, or include fire-specific operator actions (e.g., self-induced-station-blackout).

===Purpose===
This section describes the procedure for developing the Fire PRA Model to calculate CDF, CCDP, LERF, and CLERP for fire events. The procedure addresses the process of implementing temporary or permanent changes to the Internal Events PRA to quantify fire-induced CDF, CCDP, LERF, and CLERP, and for developing special models to address FEPs. The procedure also addresses the transition from temporary changes to permanent changes to the Internal Events PRA Model during the development of the Fire PRA Model.

===Scope===
This procedure addresses the following major steps for developing the Fire PRA Model for calculating CDF/CCDP and LERF/CLERP for fire events.
* Step 1–Develop the Fire PRA CDF/CCDP Model.
* Step 2–Develop the Fire PRA LERF/CLERP Model.

==Related Element(s) of ASME/ANS PRA Standard, ASME-RA-Sb-2013==

==Related NUREG/CR-6850 Appendices:==

==Supplemental Guidance==

Qualitative Screening (Task 4)

2017-07-15T06:33:05Z

144.58.50.174:

==Task Overview==
===Background===
This task identifies fire analysis compartments that can be shown to have little or no risk significance without quantitative analysis. Fire compartments may be screened out if they contain no components or cables identified in Tasks 2 and 3, and if they cannot lead to a plant trip due to either plant procedures, an automatic trip signal, or technical specification requirements.

===Purpose===
This procedure describes the criteria for qualitatively screening the fire compartments defined in Task 1.

===Scope===
This work package addresses the following issues in qualitative screening:

* Definition of screening criteria and basis, including definition of plant trip initiator and controlled manual shutdown;
* Reference to Fire PRA component list used in qualitative screening and criteria for equipment selection; and

In most fire IPEEE analyses, the primary containment was qualitatively screened. In this methodology description, the examination of potential risk associated with fires in primary containment will follow steps similar to other locations of the plant.

==Related Element(s) of ASME/ANS PRA Standard, ASME-RA-Sb-2013==

==Related NUREG/CR-6850 Appendices:==

==Supplemental Guidance==

Fire PRA Cable Selection (Task 3)

2017-07-15T06:29:19Z

144.58.50.174:

==Task Overview==

=== Background ===
This task provides instructions and technical considerations associated with identifying cables supporting those components selected in Task 2. In previous Fire PRA methods (such as EPRI FIVE and Fire PRA Implementation Guide) this task was relegated to the SSD analysis and its associated databases. This document offers a more structured set of rules for selection of cables.

=== Purpose ===
Conducting a Fire PRA in accordance with this procedure necessitates an analysis of fireinduced circuit failures beyond that typically conducted during original Fire PRAs. The circuit analysis elements of the project are conducted in three distinct phases:

* Fire PRA cable selection (Task 3),
* Detailed circuit failure analysis (Task 9), and
* Circuit failure mode likelihood analysis (Task 10).

This chapter provides methods and instructions for conducting the first phase of circuit analysis–selecting Fire PRA cables (Task 3). The purpose of Task 3 is to identify for all Fire PRA components the circuits/cables3 associated with the components and the routing/plant location of the identified circuits/cables. These relationships can then be used to determine the Fire PRA components potentially affected by postulated fires at different plant locations.

In most cases, it is advantageous to perform some or all of Task 9 (detailed circuit failure analysis) coincident with Task 3. The degree to which Task 3 and Task 9 are combined is highly dependent on numerous plant-specific factors. Considerations for combining the two tasks are incorporated in relevant sections of Chapter 3.

=== Scope ===
Chapter 3 provides methods and technical considerations for identifying cables to be included in the Fire PRA Cable List. This task contains the following key elements:

* Identify cables associated with Fire PRA equipment,
* Determine plant routing and location for the Fire PRA cables,
* Identify Fire PRA power supplies, and
* Correlate Fire PRA cables to Fire PRA equipment and plant locations (fire compartments and/or fire areas).

Implementation of plant-specific quality assurance and configuration control requirements that might apply to a Fire PRA is not within the scope of this task. Nor does this task address validating the accuracy of plant-specific data extracted from plant drawings, documents, or databases. Each plant should follow appropriate quality assurance, administrative, and configuration control procedures applicable to the work conducted. The need to validate input source documents should be addressed as part of assembling the prerequisite information.

==Related Element(s) of ASME/ANS PRA Standard, ASME-RA-Sb-2013==

==Related NUREG/CR-6850 Appendices:==

==Supplemental Guidance==