ML19162A400
| ML19162A400 | |
| Person / Time | |
|---|---|
| Issue date: | 06/13/2019 |
| From: | Office of Nuclear Regulatory Research |
| To: | |
| T. Rivera | |
| Shared Package | |
| ML19162A398 | List: |
| References | |
| Download: ML19162A400 (19) | |
Text
NEI 00-01, Revision 2 May 2009 Table G-1 BWR Generic MSO List Plant type (note: may be applicable to other plant MPL # Scenario Description Notes types)
Reactivity Control C71 RPS SCRAM Circuits: Refer to the May be addressed by actions already included in the BWROG "White Paper" on IN 2007- plant EOPs. This is an issue inside and outside of
- 07. The "White Paper" explains that a the Control Room. Reactivity Control is addressed single hot, should it occur in the right by having as link between the Fire Safe Shutdown location in the right circuit, could Procedures and the Procedure to either vent the prevent 1/4 of the rods from inserting. scram air header or depower RPS (or reactor trip Similarly, two (2) hot shorts in the bus) to accomplish the SCRAM should manual 1a right location in the right circuit could scram from the Control Room not be effective. All prevent a full scram. Note: Single hot short can not also fail backup scram system C71 Multiple pilot valve fail to de-energize Scram pilot solenoids failure to de-energize so SV 1-17 & SV 1-18 scram valve pilot air header stays pressurized (might be redundant with 1a, check white paper) 1b All Reactor Coolant Makeup Control G-2
NEI 00-01, Revision 2 May 2009 Table G-1 BWR Generic MSO List Plant type (note: may be applicable to other plant MPL # Scenario Description Notes types)
B21 (Main Steam) Head vent valves (2) Valve Numbers MS-V-1, MS-V-2 or similar.
Spuriously Open. Scenario may be screened, depending on line size and criteria for required versus available RCS 2a Injection rate. Refer to PRA criteria about how big All of a steam line break is of concern, and use that to determine if the Scenario is of interest.
B21 (Main Steam) MSIV's hot short results Valve numbers MS-V-22A-D, MS-V-28A-D or in MSIVs failing to close or re- similar. The postulated scenario involves failure of opening. redundant, normally open, Main Steam Isolation Valves (MSIV) in one of the four Main Steam Lines 2b (MSL) to close on demand. Each MSIV has an AC BWR2/3/4/5/6 and a DC solenoid valve (Note: Some BWRs use all DC solenoids). Both valves de-energize to close the MSIV. May need to look at MSIV reopening, if closed on a fire.
B21 (Main Steam), Main Steam Line Drain Valve numbers MS-V-16, MS-V-19 (F016 and Shutoffs spuriously open. F019) or similar. May be an additional downstream manual valve MS-V-21 (F021) with an orificed 2c BWR2/4/5/6 bypass. Valve Motor may be removed or have power disconnected. May be able to analyze flow rate as an acceptable inventory loss.
B31 Failure to trip the Recirc pump on loss Reactor seal leakage. Spurious closure of IV-70-92, of cooling. Recirc pump seal failure loss of RBCLC pumps and loss of service water, Applicable to 2d LOCA results in loss of RBCLC and consequential seal one BWR2 LOCA.
C11 RPV coolant drain through the SDV vent and drain This scenario is a MSO initiated drain of reactor 2e coolant from the SCRAM Discharge Volume to the All Reactor Building sump. The scenario is triggered by MSO opening of the solenoid valves which supply control air to the air operated isolation valves.
G-3
NEI 00-01, Revision 2 May 2009 Table G-1 BWR Generic MSO List Plant type (note: may be applicable to other plant MPL # Scenario Description Notes types)
E12 Inventory control Hi/Lo pressure RHR-V-8, RHR-V-9 (F008, F009) or similar.
interface valve spurious operation - Removal of DC Control Power Fuses may resolve 2f BWR3/4/5/6 (Residual Heat Removal) SDC Suction (may not resolve 3-phase proper rotation hot shorts).
Isolation Valves This is the traditional Hi/Lo pressure interface.
E12 Inventory control valve spurious Possible path includes the Warm-up line. Valves operation - (Residual Heat Removal) RHR-V-53A & B, RHR-V-50A & B (F015A&B, Discharge to Recirc Loop Isolation F017A&B) or similar. Testable check valve will go 2g Valves closed on DP. Need to consider whether RHR BWR4/5/6 crosstie is open. T-H analysis of piping pressure/temperature may resolve. Power may be removed on Bypass.
E12 Inventory control valve spurious MOV -F022, MOV-F023 or similar. May be cut and operation - (Residual Heat Removal) Capped for some plants, or have a check valve to 2h BWR3/4 RHR Head Spray Valves prevent back flow.
E12 Spurious Operations that creates RHR RHR flow can be diverted to the containment Pump Flow Diversion from through the Containment Spray isolation valves RHR/LPCI. (E11-F016A, B and E11-F021A, B or similar),
Consider the possibility of failing either the primary containment boundary (drywell/torus junction) or internal structural elements of the pressure 2i BWR4 suppression design as a result of spraying the drywell under conditions where drywell sprays are not allowed by EOPs. Spraying into a hot dry environment in the drywell could result in a pressure reduction beyond what can be addressed by the containment vacuum breakers.
E12 Spurious Operations that creates RHR RHR flow can be diverted to the containment Pump Flow Diversion from through the RHR Torus or Suppression Pool return 2j RHR/LPCI, including diversion to the line isolation valves (E11-F024A, B and E11-Torus or Suppression Pool. F028A, B).
G-4
NEI 00-01, Revision 2 May 2009 Table G-1 BWR Generic MSO List Plant type (note: may be applicable to other plant MPL # Scenario Description Notes types)
E12 Spurious Operations that creates RHR RHR flow can be diverted to the containment Pump Flow Diversion from through the Torus or Suppression Pool Spray RHR/LPCI, including diversion to the 2k Header isolation valve (E11-F027A, B and F028 or Torus or Suppression Pool Spray similar) or RHR Warm-up Line (E11-F026B). F026 Header.
typically has power removed, and 53 is in line, typically normally closed.
E12 Spurious RHR min flow failure to open with failure to establish a RHR min flow failure to open (with spurious pump 2l discharge path. start at high pressure or RPV injection line valves All spuriously fail close). may lead to pump overheating/failure likely III.G.3 scenario.
E12 Spurious operation (open) of valve RHR A DISCH TO RADWASTE Valves F049, F040 (Radwaste letdown) or similar.
INBOARD ISOLATION and RHR F010 (Crosstie) spurious operation or if F010 is 2m BWR4/6 radwaste isolation valve open may divert flow from opposite train. F010 may have power removed.
E12 2n Spurious opening of two series RHR BWR4 unit cross tie valves BFN Only E12 2o Spurious opening of two series RHR F010 (Crosstie)valve or similar. Breaker power may BWR4 loop cross tie valves be removed.
E12 Spurious opening of F073 and F074 2p RHR service water to RHR injection flood up ESW emergency containment (core) flooder valves.
E21 Spurious Operation of normally closed Bypass Valve is normally down powered, DC Core Spray Discharge Check bypass MOV. 2 DC hot shorts can open the valve, resulting valve (equalizing valve) or testable in an alignment of High Pressure RCS pressure to 2q check valves, and core spray discharge the Low Pressure Core Spray Piping. Testable BWR5 valve F005. Check valve should go closed upon DP across valve.
G-5
NEI 00-01, Revision 2 May 2009 Table G-1 BWR Generic MSO List Plant type (note: may be applicable to other plant MPL # Scenario Description Notes types)
E21 Spurious Operations that Create Core Spray Pump Flow Diversion for CS flow can be diverted to the Torus or Suppression injection to the RPV Pool through the CS test line MOVs (E21-F015A, B or similar). Test Line is typically a 10" line with Orifice. This is a single spurious operation, so 2r should already be addressed in SSA (unless the line BWR2/4 includes 2 series valves). Should review for MSOs not addressed in SSA, such as combinations of CS test Line MOV opening and CS Discharge Valve Opening (Scenario 2O).
E21 Address Core Spray flow diversion to the equipment drains IV-40-30, 31, 32, The reference to IV-40-30, -31, -32 and -33(high 2s 33 and to the containment spray raw point vents, low point drains to Reactor Building Applicable to water system. Equipment Drain Tank{RBEDT]) MOV's should be one BWR2 pulled out as a separate specific item.
E21 Path from Core Spray injection discharge valve to reactor building Spurious actuation of vents (IV-40-30, 32) and CS equipment drain tank vent isolation Injection (10 or 11) or loop 2 (IV-40-31, 33 and 09 Applicable to 2t valves, scenario is plant specific or 08) requires 3-phase proper polarity hot shorts on one BWR2 IV-40-30 and 31 because power is removed.
E22 Spurious HPCS/HPCI operation (Note: Vessel Overfill into steam lines. Could Impair RCIC for plants where HPCI is a subset of operation (if credited) due to vessel overfill and Feedwater, scenario may involve water in the steam line. Can occur as a result of: a) continued operation of HPCI) Spurious valve Operation: Turbine Stop Valve and HPCI Discharge Shutoff Valve Spurious Operation 2u (HPCI-F067, F006 or similar), b) Damage to Cabling for transmitters (two required to start HPCI), c) Damage to High Level Trip Circuitry, or d) HPCI pump controls hot short (for either motor or TD HPCI).
G-6
NEI 00-01, Revision 2 May 2009 Table G-1 BWR Generic MSO List Plant type (note: may be applicable to other plant MPL # Scenario Description Notes types)
E41 HPCI inject to Core Spray (F037 &
2v F048 valves opening) over Potential Hi/Lo pressure interface scenario. BWR4 pressurizing CS.
E41 HPCI drain to the sump failing open AOV F004/F005 (F028, F029, and bypass is F055.)
on loss of air pressure.
2w or similar. Open drain flow path may not be BWR4 sufficient to fail HPCI function.
E41/E22 Spurious operation (open) of both of MSOs to the HPCI/HPCS discharge test line valves HPCI/HPCS CST Test Return/Bypass can divert flow to the Condensate Storage Tank. If valves. suction is from the Suppression Pool, the 2x Suppression Pool inventory is diverted to the CST. BWR4/6 Valves E41-F011, E41-F008 [E22*MOVF010 and E22*MOVF011] (MO2316, CV2315), E41-F042, E41-F041(MO2321, MO2322), or similar."
E51 RCIC Test flow to CST Stop and Valve numbers F022 and F011 or similar. The throttle valves flow diversion throttle valve and isolation valve in the return line to the Condensate Storage Tank are normally closed and at least one of the valves must remain closed to prevent flow diversion from the RCIC pump to BWR6 support the reactor inventory control function, especially during suppression pool cooling.
2y E51 RCIC Drain Pot Drains failing open on loss of air pressure AOV F025/F026 (RCIC) on the drain to the sump failing open on loss of air pressure. Does not appear to be a concern. 1inch steam line leak, assuming the BWR4 drain POT fails open. Trap would limit the flow.
Diversion would also require F0054 bypass to open.
Diversion may be too small to be a concern.
2z G-7
NEI 00-01, Revision 2 May 2009 Table G-1 BWR Generic MSO List Plant type (note: may be applicable to other plant MPL # Scenario Description Notes types)
E51 RCIC Pump Diversion through Mini The RCIC pump discharge can be diverted through Flow Line to the Suppression Pool or the test return line to the CST through a MOV test return Line. isolation valve and the common HPCI AOV throttle 2aa valve. RCIC min flow line MOV E51-F019 is BWR4 another path and a path from the pump suction to the suppression pool through MOVs E51-F029 and E51-F031.
E51 Spurious operation (open) of both of Valves 1E51*MOVF022 and 1E51*MOVF059 and RCIC TEST RETURN TO a Spurious startup signal or valves RCIC PUMP CONDENSATE STORAGE TANK DISCHARGE TEST LINE ISOLATION E51-F022, valves with suction on the Suppression RCIC PUMP TORUS SUCTION INBOARD 2ab Pool may route the RCIC inventory to ISOLATION E51-F03, RCIC PUMP TORUS BWR4/6 the CST. SUCTION OUTBOARD ISOLATION E51-F029, and HPCI/RCIC TEST RETURN REDUNDANT SHUTOFF VALVE E41-F011 or similar.
E51 RCIC Suction Valves (F010, F031 or similar) CST and Suppression Pool 2ac Suction Valves - There is a potential to isolate the BWR4 injection paths from the CST and Suppression pool to the RCIC pump.
G31 RPV bottom drain isolations to reactor Spurious operation of valves BV-37-08 and BV building equipment drain tank 09 (Dwg. C-18009). Thermal overload removed to spuriously opening prevent spurious operation. as Hi/Lo pressure interface. This is a 3-phase hot short of proper Applicable to 2ad polarity (May be only a two phase hot short because one BWR2 there are only two phases with thermal overload heaters. The third phase remains connected to the circuit).
G33 Spurious operation (open) of BOTH 1G33*MOVF001, 1G33*MOVF004 or similar.
REACTOR WATER CLEAN-UP Closed loop system, but may be a concern due to 2ae All ISOLATION Valves may route RPV high temperature in the piping for plants with low inventory into the RWCU system. pressure RWCU piping (e.g., older BWRs).
G-8
NEI 00-01, Revision 2 May 2009 Table G-1 BWR Generic MSO List Plant type (note: may be applicable to other plant MPL # Scenario Description Notes types)
G33 Spurious operation of RX Water Clean Valves RWCU-FCV-33, and RWCU-V-34 or Up valves(RWCU drain to condenser RWCU-V-35, or similar. Would require additional 2af BWR2/3/4/5 and/or radwaste collection tanks.) MOVs open to RWC; MOV 1 or 4 (or similar).
G38 Suppression Pool Drain down: One May be unique flow paths for each BWR, involving example: Suppression Pool Water any drain down path from the suppression pool. One Management system suction flow is example: If the one of two Torus Water diverted or that the return flow is Management System pumps are either running or diverted for some there may also have spuriously starts, and one of two normally closed the safeguards keep fill pumps with suction isolation MOVs open, and the normally 2ag lines to the ECCS injection lines. closed condenser isolation valve opens, then BWR4-6 Suppression Pool water is pumped to the condenser.
Torus Cleanup may be locked closed for many plants. Drain to the Condenser typically a 3" line.
Another example - Containment Spray at a plant that has a connection to RADWASTE that would divert torus water if failed open.
N21 Spurious Operations that Create Applicable to BWRs with SBFW system or other Standby Feedwater System(SBFW) motor driven FW pump.
2ah BWR4 (AC Driven FW Pump) Flow Diversion from RPV N21 Spurious operation of a feedwater or Valves 1FWS-P1A(B, C), 1FWS-MOV26A(B, C),
booster pump and a level control valve 1C33-LVF001A(B, C, D) 1C33-LVF002 or similar.
may cause uncontrolled feedwater Booster Pump operation would require decreased injection into the RPV. This could vessel pressure. Feedwater pumps may not be a also include continued operation of the concern if steam driven, and not driven of the main 2ai Feedwater Pump (driven off the main turbine shaft.. BWR2/3/6 turbine shaft). Fire damage to the feedwater pump clutch and/or associated controls could prevent tripping the pump, resulting in a serious overfeed situation.
G-9
NEI 00-01, Revision 2 May 2009 Table G-1 BWR Generic MSO List Plant type (note: may be applicable to other plant MPL # Scenario Description Notes types)
P11 Loss of CST Inventory to Hot Well Several paths exist that can cause a gravity drain of the CST to the Hotwell. The condition can happen due to spurious operation of MOVs alone, and if the normal hotwell pump or emergency hotwell pumps 2aj spuriously start, the condition is worsened. BWR2/4 Standpipes for drain paths may limit the minimum level in the CST. Should review Fire SSA assumptions for minimum level and effect of drain down.
P11 CST supply to Condensate Return This MSO involves spurious operation of MOVs in Tank (CRT) supply shutoff MOV the piping connecting the CST and CRT. If either of spurious operation two valves spuriously open, a gravity transfer can 2ak occur which can lower the water level significantly BWR4 in the CST. See discussion above on Standpipes.
Scenario not applicable to plants without a CRT or equivalent.
P11 CST discharge to Radwaste system Spurious operation of two MOVs in the Condensate shutoff MOV spurious operation system can set up a gravity drain path from the CST to the radwaste system. The water loss may need to 2al be evaluated to support the time line to reach such a BWR4 step in a manual action feasibility study. See discussion above on Standpipes.
Reactor Coolant System Pressure Control B21 Potential opening of all SRVs Multiple spurious can open a portion or all of the SRVs from conductor to conductor (cable) failures 3a or pressure switch instrumentation racks containing BWR2/4/5/6 all switches for the SRVs. GE Calc. available on SRV openings.
G-10
NEI 00-01, Revision 2 May 2009 Table G-1 BWR Generic MSO List Plant type (note: may be applicable to other plant MPL # Scenario Description Notes types)
B21 Multiple ERV (SRV) opening Safety Relief Valve-Two or More Spuriously Open "this failure requires two or more sustained fire 3b BWR2/4/5 induced failures in cables or within a control room panel to open more than one SRV."
B21 Spurious ADS: Safety Relief Valve- This postulated scenario features a failure that will Failure of ADS Initiation Logic, open multiple SRVs simultaneously and requires opening SRVs simultaneously due to energization of relays K6Aand K7A or K6B and energization of relays K7B in a two out or two taken twice logic scheme (ref. APED-B21-018<2>). As such this failure requires two sustained fire induced failures within 3c the control room panel with no damage to the BWR2/4 individual SRV control circuits to initiate ADS. It should be noted that the individual SRV control circuits are powered from and contain control logic within the panel. May not be applicable to plants that have installed confirmatory logic in ADS to prevent ADS for control room fires.
Decay Heat Removal E12 Loss of RHR suppression pool cooling Fire causes the loss of both loops of RHR due to suction valve interlock suppression pool cooling (flow control valve for interactions RHR A unavailable due to fire damage to cables; 4a BWR3/4/5/6 hot short causes shutdown cooling suction MOV RHR-V-6B to fail open, which fails RHR B suppression pool cooling due to interlocks).
E12 Failure due to diversion of suppression Loss of both loops of RHR suppression pool pool decay heat removal through 16B cooling. Loss of suppression pool leads to 4b BWR3/4/5/6
& 17B. Containment Failure the containment failure location fails HPCS.
G-11
NEI 00-01, Revision 2 May 2009 Table G-1 BWR Generic MSO List Plant type (note: may be applicable to other plant MPL # Scenario Description Notes types)
E14 Dedicated Shut Down Cooling System Spurious opening of normally closed heat exchanger
- "Spurious opening of SDC heat bypass air operated valves FCV 128, 131, and exchanger bypass valves(FCV 134. These valves fail open on loss of instrument 128, 131, and 134)" air and control power.SDC is a manually operated Applicable to 4c system and is used several hours after the event. If one BWR2 needed, these valves can be operated manually. May be a cold shutdown issue, if cooling is not needed for Hot standby.
E15 4d Dedicated Shut Down Cooling System
- "Spurious closure of Pump suction IV-80-01, 02, 21 and 22. Spurious closure {DWG BWR2 valves from torus (IV-80-01, 02, 21 18012, sh. 2}
and 22)"
E15 Dedicated Shut Down Cooling System
- "Spurious closure of Pump discharge IV-80-15, 16, 35 and 36. Spurious closure {DWG to drywell valves (IV-80-15, 16, 35 18012, sh. 1} Note: All four IV-80-15, 16, 35 and 4e BWR2 and 36)" 36 valves go open and they can not be re-positioned on loss of instrument air.
E15 Dedicated Containment Spray System
- "Spurious closure of the normally Spurious closure of the normally open MOVs BV- Applicable to 4f open Containment spray raw water 93-25, 26, 27 and 28. {DWG 18012, sh. 1} one BWR2 discharge valves (MOVs BV-93-25, 26, 27 and 28.)"
E15 Dedicated Containment Spray System Spurious opening of normally closed MOVs FCV-
- Spurious opening of normally closed 93-72 and 73. {DWG 18012, sh. 1}FCV-93-72 and Containment spray raw water to 73 are interlocked with BV-93-28 and 26 containment spray supply valves respectively (per system description SDBD 203). If Applicable to 4g (MOVs FCV-93-72 and 73) raw water intertie occurs when conditions are one BWR2 wrong, spraying the drywell with cold raw water could cause a failure of the pressure suppression function of containment.
G-12
NEI 00-01, Revision 2 May 2009 Table G-1 BWR Generic MSO List Plant type (note: may be applicable to other plant MPL # Scenario Description Notes types)
E15 Dedicated Containment Spray System Spurious opening of normally closed MOVs FCV-
- Spurious opening of normally closed 93-71 and 74. FCV-93-71 and 74 are interlocked Applicable to 4h Containment spray raw water to core with BV-93-25 and 27 respectively (per system one BWR2 spray supply valves (MOVs FCV description SDBD 203).
71 and 74)
E15 Dedicated Containment Spray System Spurious opening of normally closed MOVs IV - Spurious opening of normally closed 4i 114 and 115 causing flow diversion in containment BWR2 Containment spray venting valves(
spray. {DWG 18012, sh. 2}
MOVs IV-80-114 and 115)
E21 Dedicated Core Spray System -
"Spurious closure of normally open Spurious closure of normally open MOVs IV-81-01, 4j BWR2 torus suction valves (MOVs IV-81-01, 02, 21 and 22. {DWG 18007, sh. 1}
02, 21 and 22)"
E21 Dedicated Core Spray System -
Spurious closure of normally open Spurious closure of normally open MOVs IV-40-02 4k BWR2 RPV injection valve (MOVs IV-40-02 and 12. {DWG 18007, sh. 1}
and 12)
E52 Isolation Condenser - "Spurious closure of Steam line isolation valves Spurious closure of IV-39-07, 08, 09 or 10 results in (IV-39-07, 08, 09 or 10) results in failure of decay heat removal. Failure to isolate for pipe breaks. Based on the RIS evaluation, it was failure of decay heat removal. Failure to isolate for pipe breaks. " shown that credible circuit failure modes may exist 4l BWR2/3 to spuriously close the DC motor operated valves IV-39-07 and IV-39-08. This spurious closure is based on conductor to conductor hot short failures of two cables.
E52 Isolation Condenser - Condensate AOVs IV-39-05, 06 fail to open resulting in failure return isolation valve failure to 4m of EC system. Failure to stay closed for pipe BWR2/3 move/remain in correct position breaks. Dwg. 18017-1 G-13
NEI 00-01, Revision 2 May 2009 Table G-1 BWR Generic MSO List Plant type (note: may be applicable to other plant MPL # Scenario Description Notes types)
E52 Isolation Condenser - Failure of Vent Failure of IV-05-02 and 03 to close or hot short(s) to main steam line valve (IV-05-02 that keeps both valves open results in loss of and 03) to close or hot short(s) that inventory. These valves receive a signal to close on 4n keeps both valves open results in loss vessel Lo-Lo level. IV-05-01, 04, 11, 12 do not BWR2/3 of inventory. receive a signal to close on EC actuation. {DWG 18017, sh. 1}
E52 4o Isolation Condenser - "Failure of Vent Failure of IV-05-01, 11, 12, 04 to close results in to main steam line valves (IV-05-01, loss of inventory. These valves do not receive a BWR2/3 11, 12, 04) to close results in loss of signal to close on EC actuation. {DWG 18017, sh.
inventory." 1}
E52 4p Isolation Condenser - Spurious Spurious opening of normally-closed BV-05-05 and opening of normally-closed Vent to 07 results in loss of inventory. {DWG 18017, sh. 1}
BWR2/3 torus valves (BV-05-05 and 07) results in loss of inventory.
E52 4q Isolation Condenser - Spurious closure Spurious closure of BV-60-13 results in loss of of Cross-connect valve(BV-60-13) on cross-connect capability of makeup source. {DWG BWR2/3 makeup line results in loss of cross- 18017, sh. 1}
connect capability of makeup source.
T23 4r Containment Over Pressure (COP), A General Review of NPSH and Containment Over NPSH loss due to spurious initiation of Pressure should be performed to look for other containment sprays. pathways such as containment inerting system or other containment isolations, other than the 3 listed here. COP is only an issue for plants that credit COP for NPSH concerns. Sprays initiated with hot, dry Mark I drywell could result in a rapid depressurization of (BWR2/3/4) the drywell, that is so rapid the vacuum breakers can not mitigate, resulting in collapse of the torus ring header and possible loss of pressure suppression design function.
G-14
NEI 00-01, Revision 2 May 2009 Table G-1 BWR Generic MSO List Plant type (note: may be applicable to other plant MPL # Scenario Description Notes types)
T23 Containment Over Pressure (COP), Spurious opening of Containment Vent, resulting in NPSH loss, Spurious opening of Containment depressurization, following a loss of Containment Vent. Suppression pool cooling. Containment vent Mark I 4s through pathways not including the rupture disc. (BWR2/3/4)
COP is only an issue for plants that credit COP for NPSH concerns.
T23 Containment Over Pressure (COP), Spurious opening of the drywell floor drain sump, NPSH loss, Spurious opening of the since it isn't directly connected to the airspace. COP Mark I 4t drywell floor drain sump valves. is only an issue for plants that credit COP for NPSH (BWR2/3/4) concerns.
T23 Spurious opening of torus vent and Spurious opening of torus vent and purge valves IV-purge valves. 201-07, 08, 16, and 17 or BV-201-21 and 22 will 4u BWR2 lead to loss of containment isolation.
T23 4w Mark I containment with Torus Ring Header: too much flow through the NPSH Issue for the operating/credited pump. May ring header due to spurious operation be caused by a false LOCA signal.
of multiple pumps (more than allowed by design) from the ring header.
Support Systems E12 Additional components load onto credited diesel generator Scenario causes diesel generator overloading and inoperability. Note: Scenario very site specific.
Interlocks may prevent this from occurring. In 5a All addition, overloading may also occur if proper load sequencing is bypassed via hot shorts, causing simultaneous loading of multiple components onto the EDG.
G38 Spurious operation (open) of both Drain down of suppression pool below minimal 5b SUPPRESSION POOL CLEAN-UP level. 1RHS*AOV62, 1RHS*AOV63 or similar BWR6 ISOLATION Valves.
G-15
NEI 00-01, Revision 2 May 2009 Table G-1 BWR Generic MSO List Plant type (note: may be applicable to other plant MPL # Scenario Description Notes types)
P41 Emergency Service Water pump Prior to isolation of the circuits and component operation at shutoff head control at the remote shutdown panel, the Auto start or spurious Control Room fire induced start of the Emergency Service Water (ESW) Pump followed by a spurious closure of the ESW Pump Discharge Valve. The ESW Pump would be operating with no flow until isolation and control from remote station 5c is achieved. III.G.3 only because for non-III.G.3 BWR4/6 areas not employing isolation transfer switches such fire damage would also disable the ability of the pump to operate.
Spurious RHR Service Water pump Prior to isolation of the circuits and component operation at shutoff head control at the remote shutdown panel, the Control Room fire causes a start of the Residual Heat Removal Service Water (RHRSW) Pump followed by a spurious closure of the RHRSW Pump Discharge Valve. The RHRSW Pump would be operating with no flow until isolation and control 5d from remote station is achieved. III.G.3 only BWR4/6 because for non-III.G.3 areas not employing isolation transfer switches such fire damage would also disable the ability of the pump to operate.
G-16
NEI 00-01, Revision 2 May 2009 Table G-1 BWR Generic MSO List Plant type (note: may be applicable to other plant MPL # Scenario Description Notes types)
P41 Spurious operation (open) of both 1E12*MOVF094 AND 1E12*MOVF096 or similar.
RHR SERVICE WATER Diversion of Service Water could also cause failure ISOLATION (Crosstie) valves in a of the credited Service Water Pump due to runout.
5e BWR6 loop may result in diversion of service water flow from the RHR heat exchangers.
R43 Scenario causes damage to diesel generator by closing into a live bus out-of-phase. Note: Scenarios are very site specific. Interlocks may prevent this 5f Non-synchronous paralleling of EDG from occurring. All with on-site and off-site sources through spurious breaker operations R43 Non-Synchronous Paralleling -
inadvertent cross tie breaker operation between opposite divisions (e.g., Scenario causes damage to diesel generator by 4160V, 480V) of Div 1(2) EDGs closing into a live bus out-of-phase. Note: Scenario 5g All through Spurious Operation of 480 V very site specific. Interlocks may prevent this from Breakers or the Divisional Cross-Tie occurring.
through 4160 V Maintenance Tie Breakers R43 Non-Synchronous Paralleling -
inadvertent cross tying the off site Spurious breaker closings between separate 5h All power sources through the on-site divisions of off-site power.
busses & breakers.
G-17
NEI 00-01, Revision 2 May 2009 Table G-1 BWR Generic MSO List Plant type (note: may be applicable to other plant MPL # Scenario Description Notes types)
R43 Spurious Diesel generator operation without cooling water The fire causes the startup of the Emergency Diesel Generator, Spurious closure of the ESW Pump Discharge Valve or trip of the ESW Pump would stop the cooling water supply to the Emergency Diesel Generator. Running the Emergency Diesel 5i Generator with a loss of cooling water could trip the All diesel on high temperature. If the fire has resulted in the actuation of a LOOP or LOCA bypass of the high temperature trip, the diesel could continue to run until damage from over-temperature conditions stop it.
R43 Service Water System - Spurious operation (open) of both cross- 1SWP*MOV505A, 1SWP*MOV505B or similar, 5j connection valves would cause an for RHR Service Water, F119A/B or similar would All uncontrolled loss of service water to have to open.
the opposite division.
G-18
NEI 00-01, Revision 2 May 2009 Table G-1 BWR Generic MSO List Plant type (note: may be applicable to other plant MPL # Scenario Description Notes types)
R24N/A Spurious motor-operated valve General scenario is that fire damage to motor-operation, AND Wire-to-wire short(s) operated valve circuitry causes spurious operation.
bypass torque and limit switches If the same fire causes wire-to-wire short(s) such that the valve torque and limit switches are bypassed, then the valve motor may stall at the end of the valve cycle. This can cause excess current in the valve motor windings as well as valve mechanical damage. This mechanical damage may 5k be sufficient to prevent manual operation of the All valve. Scenario only applies to motor-operated valves. Note this generic issue may have already been addressed during disposition of NRC Information Notice 92-18. This disposition should be reviewed in the context of multiple spurious operations and multiple hot shorts.
T41 Loss of HVAC: Spurious isolation of Perform review to identify spurious failures that HVAC to credited loads could cause isolation of Heating Ventilation and Air Conditioning (HVAC) to credited loads. Credited loads may include pump rooms, switchgear rooms, and rooms containing solid state control systems.
5l Examples of spurious failures include spurious All damper isolation and spurious isolation of cooling flow to chillers. Also look at Fire-induced damage causes loss of both cooling fans and cooling pumps on startup transformer when offsite power is credited.
W25/W24 Cooling pond (UHS) inventory loss -
Cooling pond to tower cross tie.
Drain down of dedicated ultimate heat sink (cooling 5m HV12-111, HV12-113 fail open, Can All pond) to non- safety systems pump spray pond to the cooling tower (non-UHS).
G-19
NEI 00-01, Revision 2 May 2009 Table G-1 BWR Generic MSO List Plant type (note: may be applicable to other plant MPL # Scenario Description Notes types)
Process Monitoring 6a No generic Scenarios identified G-20