ML060250038
| ML060250038 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 11/07/2005 |
| From: | Duke Energy Corp |
| To: | Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML060240605 | List: |
| References | |
| Download: ML060250038 (28) | |
Text
Duke Power Appendix R Reconstitution Oconee (ONS)
November 07, 2005 1 ATTACHMENT 5
Purpose
Present General Overview of Reconstitution Methodology
Show how Reconstitution Data/Information is used as a direct input into the Fire PRA
Discuss How Recent Staff Positions May Impact NFPA-805 Transition 2
Appendix R Reconstitution Safe Shutdown Methodology
Split into Three Phases:
Phase I - Safe Shutdown Equipment List (SSEL) and Logic Diagrams
Phase II - Cable and Fire Area Analysis -
identifies all cable/component hits
Phase III - Performance Based/Risk Informed analysis of multiple spurious actuations in accordance with NFPA-805 3
Appendix R Reconstitution Safe Shutdown Methodology -
continued
Phase I
Define Safe Shutdown Functions, Systems and Components
Safe Shutdown components listed in a Safe Shutdown Equipment List (SSEL)
System and Component Dependencies are documented on System and Component Logic Diagrams 4
Example System Logic Diagram Normal Plant Operating at Power Fire Occurs in Any Fire Area Reactor Pressure and Reactor Reactivity Control Decay Heat Removal Process Monitoring Support Functions Inventory Control Reactor Coolant System Reactor Pressure Control Reactor Coolant Reactor Coolant System Reactor Trip System Mechanical Support Functions Electrical Support Functions (RC) Inventory Control Instrumentation (RC)
Chemical & Volume Main Steam Systems Reactor Coolant System Reactor Coolant System Condenser Circulating Control Systems Steam Generator Level (MS/SD) (RC) (RC) Water System (CCW) Keowee Emergency (HPI/LPI/SF) and Pressure (FDW/MS)
Power (ELK)
Note 1 100KV Auxiliary Chemical & Volume Chemical & Volume Power (EL)
Control Systems Service Water Systems Emergency Feedwater Control Systems (HPI/LPI/CF) (LPS/HPS)
Systems (FDW/C/CCW) (HPI/LPI/SF) Tank Level Indicators Note 2 Note 1 Note 1 (C/LPI)
Component Cooling 230KV Switchyard & Keowee Underground System (CC) 125VDC System (SYD) Path (ELK)
Residual Heat Removal Residual Heat Removal System (LPI) System (LPI)
Diagnostic Indicators HVAC (VS)
SSF Diesel Generator 4160/600/208VAC SSF 4160/600/120VAC Auxiliary Power (EL)
Power (EL) 250VDC Power &
125VDC/120VAC SSF 125VDC/120VAC Vital Power (EL) Power (EL)
NOTES
- 1. Two paths are credited for Chemical and Volume Control: a) High Pressure Injection Pumps supplied from Note 4 the BWST (LPI System) with normal Letdown available, or b) SSF RC Makeup Pump (HPI System) supplied from the Spent Fuel Pool (SF System) with Letdown back to the Spent Fuel Pool.
- 2. Four paths are credited for Emergency Feedwater: a) Turbine Driven EFW Pump supplied from either the hotwell or the Upper Surge Tanks b) Motor Driven EFW Pumps supplied from either the hotwell or the Upper Surge Tanks, QA CONDITION 1 c) ASW pump supplied from the CCW System, and d) the SSF Auxiliary Service Water Pump supplied from the CCW System. REV. PREPARED BY DATE CHECKED BY DATE APPROVED BY DATE REVIEWED BY DISCIPLINE DUKE POWER COMPANY OCONEE NUCLEAR STATION UNITS 1, 2, & 3
- 3. Note Deleted APPENDIX R SAFE SHUTDOWN
- 4. The SSF diesel generator does not have enough capacity to power all required cold shutdown loads; therefore, SYSTEM LOGIC DIAGRAM SHEET 1 OF 1 the Keowee Underground Path is credited as a power source for an Appendix R fire requiring shutdown from the SSF. 1 0 James L. McGraw 12/20/01 Leonard J. LaCrosse 12/20/01 Joseph G. Redmond 12/20/01 DWG. NO. APPENDIX R - LOGIC - U0 - SLD - 001 5
Example Component Logic Diagram - HPI System Demand for HPI System LOGIC-U1-LPI-001 BWST Water Available (1) Via LPI System U1 & U2 SFP E 1HP VA0426 AVAILABLE OPEN E
1HP VA0023 OPEN NC/FAI Note 3 LOGIC-U1-LPS-002 NO/FAI Note 7 E 1SF VA0001 1HP VA0428 OPEN OPEN (1)
E 1HP VA0024 E 1HP VA0098 E 1HP VA0025 NO NC/FAI Note 3 OPEN OPEN OPEN E
1SF VA0097 1SF VA0002 NC/FAI NO/FAI NC/FAI OPEN OPEN E NC/FAI NO 1HP VA0115 1HP VA0116 OPEN OPEN E
1SF VA0082 SSF Letdown NO/FAI NC OPEN Path Established NC/FAI LPS System Supply to HPI Pump/Motor Cooling Jackets LOGIC-U1-HPI-003 1HPIPU0005 (1)
ON OFF Note 10 E
1HP VA0417 1HPIPU0001 1HPIPU0002 1HPIPU0003 CLOSED ON ON ON Letdown Path Established Note 5, 6 NC/FAI Note 3 Note 5, 6 Note 5 E
1HP VA0405 Note 1 LOGIC-U1-HPI-002 CLOSED NC/FAI Note 3 RC Inventory Control Established (Transition to (1)
E 1HP VA0398 OPEN Cold Shutdown)
E 1HP VA0409 E 1HP VA0410 OPEN OPEN NC/FAI NC/FAI NC/FAI Seal Injection & RC Makeup Flowpath Established Notes
- 1. To preclude excess boron dilution during Mode 5, one HPI pump is repaired (if required) to inject to the RCS with the suction aligned to the BWST. If additional letdown is needed, the RCS letdown can be provided back to the SFP for a "feed and bleed" method of increasing boron concentration through the RC Makeup System.
- 2. The instrumentation required to be functional is dependent on the HPI flow paths chosen for hot and cold shutdown.
1HP VA0031 1HP VA0140 E 1HP VA0027 3. Valves 1HP VA0405, 0417, 0426 & 0428 are shown on sheets 1 and 2 of this drawing OPEN THROTTLED OPEN series. Valves 1HP VA0001, 0002, 0003, & 0004 are shown on sheets 2 and 3 of this P
1HP VA0120 NT/FO NC NO/FAI drawing series.
OPEN 4. Instruments 1HPIPT0016 and 1HPIP0029 are currently credited for postulated fires in NT/FO West Penetration Room, Cable Trench and SSF. Since fires in these areas will not E
1HP VA0026 1HP VA0472 OPEN affect instrument air, assuming the power supply to the IA compressors are available, LOGIC-U1-HPI-002 LOGIC-U1-RC-002 OPEN 1HP VA0122 THROTTLED the devices can be credited for postulated fires in these areas. If Pressurizer Level NC/FAI indication is available then 1HPIPT0016 and 1HPIP0029 are not required. If these NC NC instruments are required for other fire scenarios, additional analysis will be required.
(3) (2) 1HP VA0355 OPEN Seal Injection Flowpath (Notes are continued on sheet 2.)
NC/FC Established LOGIC-U1-RC-002 Aux. Pressurizer Spray to RC System Charging (1) QA CONDITION 1 Flowpath Established REV. PREPARED BY DATE CHECKED BY DATE APPROVED BY DATE REVIEWED BY DISCIPLINE DUKE POWER COMPANY Note 1 OCONEE NUCLEAR STATION UNIT 1 LOGIC-U1-RC-001 (1)
APPENDIX R SAFE SHUTDOWN 2
COMPONENT LOGIC DIAGRAM LOGIC-U1-HPI-002 HIGH PRESSURE INJECTION SYSTEM (HPI)
(2) 1 Ronald J. Cichon 12/23/02 William M. McDevitt 12/23/02 Joseph G. Redmond 12/30/02 SHEET 1 OF 4 6 0 James L McGraw 12/20/01 Leonard J. LaCrosse 12/20/01 Joseph G. Redmond 12/20/01 DWG. NO. APPENDIX R - LOGIC - U1 - HPI - 001
Example Safe Shutdown Equipment List Page 7
Appendix R Reconstitution Safe Shutdown Methodology -
continued
Phase II
Identify cables for each component
Identify routing for each cable
Routing through each Fire Area documented
Fire Area damage assessments performed
Results of damage assessments used with Logic Diagrams to determine impact on Safe Shutdown Functions
Loss of Safe Shutdown Functions addressed through Appendix R Issue Resolution Process for spurious actuations within Design Basis 8
Example Circuit - HPI Pump 9
Example Safe Shutdown Cable Selection Worksheet Page 10
Example Cable Block Diagram 11
Example Cable Routing Worksheet Page 12
Example Simplified Cable Layout Turbine Bldg Electrical Switchgear Pump 3/ Cable Main Control Room Room Power Cable Control Room Cables Main Pump DC Control Control Power Board DC Control Equipment Power Cabinet Room 13
Example Fire Area Compliance Assessment Page 14
Appendix R Reconstitution Safe Shutdown Methodology -
continued
Phase III
As Dennis will be explaining in more detail, results of Phase II are combined with an extensive Multiple Spurious Review to address completeness of multiple spurious population
Deterministic Analysis Output (Phase II)
PRA Cut Set Review
Expert Panel Review 15
SSDA/Fire PRA
All critical data originally entered into the Safe Shutdown Database (ARTRAK) forms the basis for the Fire PRA
Components
Cables
Cable Routes
Fire Areas/Zones
Intent is to make the SSDA and Fire PRA databases match, one-for-one 16
NFPA-805 Deterministic Methodology Transition
In order to determine the need for Change Evaluations, each fire area must be evaluated to determine if it successfully meets one of the deterministic criteria in NFPA-805
One train maintained free of fire damage (old III.G.1)
Two trains in same area with deterministic solution (Old III.G.2)
3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> barrier between trains
1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> barrier with suppression and detection
20 foot of separation with suppression and detection and no intervening combustibles
Alternate Shutdown (old III.G.3) 17
Deterministic Category Impacts
Fire Areas/Zones where redundant trains are located in separate fire areas crediting III.G.1 with operator manual actions on the fire affected train may be transitioned as deterministic; prior approval not required (note that the manual action will be treated as performance based with respect to feasibility)
Fire Areas/Zones crediting III.G.2 that have manual actions will need to be transitioned as risk informed/performance based (under the current rules, they require prior NRC approval; under NFPA-805 rules, they will require a Change Evaluation)
Fire Areas/Zones crediting III.G.3 that have manual actions may be transitioned as deterministic; prior approval not required (but performance based with respect to feasibility) 18
Deterministic Category Impacts 3/
Pump Power Cable Room Electrical Switchgear A:
Pump A
Electrical Switchgear B
Pump Room 3/ Cable Main Control Room Power Cable Room DC Control DC Control Power Pump Power Main B DC Control DC Control Control Power Power Board Cabinet Cabinet Control B A: Cables Equipment Room 19
Potential Impact of Recent Staff Interpretations
Requirement to protect all associated circuit cables that could negatively impact safe shutdown may be impossible to achieve
Consider a simple example: (See next page)
A hypothetical plant has a switchgear room arrangement that requires one of the switchgear rooms to credit III.G.2 for safe shutdown (20 foot of separationetc.)
20
Potential Impact of Recent Staff Interpretations 3/
Pump Power Cable Room Electrical Switchgear B
Pump B
Electrical Switchgear A
Pump Room 3/ Cable Main Control Room Power Cable Room DC Control DC Control Power Pump Power Main A DC Control DC Control Control Power Power Board Cabinet Cabinet Control A B Cables Equipment Room 21
Potential Impact of Recent Staff Interpretations
Consider a fire in Switchgear Room A
Causes a spurious injection into RCS as a direct result of a single hot short that starts HPI Pump A
Start of HPI Pump A can have a direct impact on success of safe shutdown due to possible increase in Pressurizer level to the point where passing solid water through the Pressurizer Safety Valve fails the valve open
This negative impact results in consideration of spurious HPI pump start as Associated Circuit 22
Potential Impact of Recent Staff Interpretations 23
Potential Impact of Recent Staff Interpretations 24
Potential Impact of Recent Staff Interpretations
Consider a fire in Switchgear Room A -
continued
New interpretation that no manual actions are allowed prevents the ability to terminate the fire affected train
Normal controls could be damaged by fire
Design of injection systems normally means there is no redundant isolation valves in series (uses check valves)
Combination of Associated Circuit definition and III.G.2 manual action position would require that the circuit be protected 25
Recommendations
Consider revising policy to allow local operator manual actions to terminate undesirable impacts of spurious actuation of the fire affected train
This is not unlike the existing allowance for local operator manual actions in areas crediting III.G.1
Continuation of the current policy to require protection of associated circuits that are part of the fire affected train is impossible to meet
Would require fire wrap/protection in addition to 3-hour barriers separating trains 26
How This Affects NFPA-805 Transition
Inability to deterministically treat local operator manual actions to terminate injection/impacts on fire affected trains adds unnecessary change evaluations now and in the future (continuing configuration management) 27
Summary
Appendix R Reconstitution Data forms the foundation of the Fire PRA
Recent Staff Interpretations could have a substantial impact on transition scope, cost and schedule 28