ML072780167
| ML072780167 | |
| Person / Time | |
|---|---|
| Site: | Harris  |
| Issue date: | 08/07/2007 |
| From: | Thompson S Nuclear Generation Group, Progress Energy Co |
| To: | Office of Nuclear Reactor Regulation |
| Oudinot D | |
| Shared Package | |
| ML072830337 | List:
|
| References | |
| Download: ML072780167 (9) | |
Text
NFPA 805 Transition August Pilot Observation Target Selection Sarah Thompson, Fire Protection Engineer August 7, 2007 Bethesda, MD
Page 2 NFPA 805 Target Selection Introduction O Iterative Approach O Fire PRA scenarios Z Full compartment and ignition source basis Z Start with scoping results Z Include transient Z More refined analysis as needed O Change Evaluations Z Start with Fire PRA scenario results Z Add detail as needed to support evaluations O Document analysis results in common calc Z Only includes detail beyond scoping level
Page 3 NFPA 805 Target Selection Fire PRA Scenario Scoping Recap O Purpose - NUREG/CR-6850 Z Screen out those fixed ignition sources that do not pose a threat to the targets within a specific fire compartment, and Z To assign severity factors to unscreened fixed ignition sources O Zone of Influence (ZOI) Determination Z NRC Fire Dynamics Tools (FDTs)
O Walkdowns by Source to Identify Targets Z Collected target data, where targets included conduits, plan points, cable trays, other sources, and intervening combustibles O Source-Target Database Z Multiple HRR
Page 4 NFPA 805 Target Selection Fire PRA Scenario Refinements O NUREG/CR-6850 Methods for Reducing ZOI Z Double-wall cabinets with air gap - limits horizontal flame propagation Z Non-vented cabinets with multiple points of contact -
flame propagation limited O Addressing HGL Z Screen based on the most conservative of the MQH natural ventilation and Beyler closed door methods O Examples from the supporting calculation Z MCC Example w/ FDTs Z MQH/Beyler HGL Screen Z Transient, Detailed Flame Spread Tool w/ CFAST
Page 5 NFPA 805 Target Selection Treatment of Transients O Transient Exclusion Zones Z Do not postulate specific transient fires for change evaluations Z PRA addresses potential breakdown of administrative controls O Non-Exclusion Zones Z Postulate transients fire scenarios based on change evaluations needs Z PRA placement of transients same as that for exclusion zones
Page 6 NFPA 805 Target Selection Change Evaluation Support O Change Evaluation Target Selection Z Fixed ignition sources that could directly impact the targets of concern based on physical location. Target data captured in PRA database - refine as needed.
Z Fixed ignition sources that could remotely impact the targets of concern via flame spread or fire propagation.
Z Fixed ignition sources that could remotely impact the targets of concern through generation of a hot gas layer.
Z Transient ignition sources, in addition to those in the PRA database, are postulated when needed.
O Task iteration is expected Z As we develop more data about each fire scenario we can better determine the need for additional data to address the issues.
Page 7 NFPA 805 Target Selection Data Packaging O Most of data is in the PRA database O Refinements for select scenarios are in a calculation by compartment/fire area O Engineering review process used for calculation O Quality is driven by NUREG-1824, Verification and Validation of Selected Fire Models for Nuclear Power Plant Applications
Page 8 NFPA 805 Target Selection Closing O Where are we now?
Z Completed initial target data collection for fixed ignition sources Z Finalizing PRA target selection for transient ignition sources Z Performing ZOI refinement Z Scenario selection and fire modeling using simple tools as a first cut O Whats next?
Z Use risk input to have a focused approach on more detailed and complex modeling efforts
Page 9 NFPA 805 Target Selection Questions?
Comments?
Concerns?