ML22153A529

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ES-D-1 Clinton Jan 2022
ML22153A529
Person / Time
Site: Clinton Constellation icon.png
Issue date: 01/28/2022
From: Bruce Bartlett
NRC/RGN-III/DRS/OLB
To:
AmerGen Energy Co
Bartlett B
Shared Package
ML20136A320 List:
References
Download: ML22153A529 (9)
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ILT 20-1 NRC Exam Scenario 1 Rev. 0 ILT 20-1 NRC Exam Scenario 1 D-1.docx Page 1 of 9 Appendix D Scenario Outline Form ES-D-1 Facility: Clinton Power Station Scenario No.: 1 Operating Test No.: 2022-301 Examiners: ____________________________

Operators: ____________________

Initial Conditions:

Mode 1 at ~76% power to support performance of CPS 9031.07 Main Turbine Control Valve Tests on the next shift.

Thunderstorms are expected in the area within the next hour.

CY Pump B (0CY01PB) is OOS for maintenance. Not expected back this shift.

Turnover:

First Priority - Perform CPS 9061.03C012 Week 12 - CM, SF, SM, LD ISOL Valve Operability Checklist sections 8.12.7 (Method B). Position indication testing is NOT required. Do NOT restart SF after the completion of 9061.03C012/D012.

Maintain power at ~76% power throughout the shift.

Critical Tasks:

[CT-1] Shut SRV prior to Suppression Pool Temperature reaching 110F.

[CT-2] TSA-2 Initiate ADS (7 SRVs) within 17.5 minutes of blowdown being required (Rx Level at TAF).

[CT-3] Maximizes ECCS injection by starting the LPCS Pump and opening 1E21-F005 to restore RPV water level above TAF within 10 minutes after RPV level reaches -187.

Event No.

Malf. No.

Event Type*

Event Description 1

None N-BOP (NEW) Perform 9061.03C012 Week 12 - SF Valve Operability Checklist 2

A01_A01_02_5_TVM=2 C-ATC B RWCU pump seal plate temperature high 3

A11_A05_S40_2 ON A11_A02_07_4_TVM 2 A_11_A08_DS30_1 OFF TS-SRO Loss of Control Power to Suppression Pool Dump Valve (1SM001A) 4 A01_A02_01_8_TVM steady C-ATC (NEW) Clogged oil filter Condensate Booster Pump A 5

YPXMALSE_77 to 50 C-BOP Inadvertent opening of a SRV 6

A05_A01_A0108_3_TVM steady A05_A01_A0108_5_TVM steady C-BOP TS-SRO Failure of DG Fuel Oil Transfer Pump 1A to auto start 7

YFFWPPSS_11 YAFWPPDE_9 C-BOP R-ATC Loss of CY - Rapid Plant Shutdown 8

RAT_B_OVERCURRENT YARIMVFP_2 = 0 ED17B221C1FO YPXMALSE_511 YP_XMFTB_3986 M-All (NEW) LOCA / RAT trip / E51-F013 Failure / Loss Div 3 4160V Bus / TAF Blowdown 9

YP_XMFTB_4106 lp11acld001fsp=True C-All (NEW) LPCS Fails To Auto Start LPCS Injection Valve 1E21F005 Fails to Auto Open at 472 psig RPV pressure (N)ormal, (R)eactivity, (I)nstrument, (C)omponent, (M)ajor NEW - Not used on the previous two (2) NRC exams.

ILT 20-1 NRC Exam Scenario 1 Rev. 0 ILT 20-1 NRC Exam Scenario 1 D-1.docx Page 2 of 9 Appendix D Scenario Outline Form ES-D-1 Scenario No.: 1 Operating Test No.: 2022-301 Narrative Summary Event #

Description

1.

Perform 9061.03C012 Week 12 - SF Valve Operability Checklist The SRO directs BOP to perform CPS 9061.03C012 Week 12 - SF Valve Operability Checklist section 8.12.7 (Method B).

2.

B RWCU pump seal plate temperature high Annunciator 5000-2E CLEANUP PUMP SEAL GLAND PLATE TEMP HI comes in due to RWCU Recirc Pump B (1G33-C001B) developing excessive seal leak. The ATC Operator will secure RWCU pump B, throttle F/D bypass valve (1G33-F044) to maintain RT system flow ~ 150 gpm and coordinate field actions per CPS 3303.01 Reactor Water Cleanup (RT) Sections 8.1.3 System/Filter Demin Flow Control and 8.1.4 Removing RWCU Pump from Service.

3.

Loss of Control Power to Suppression Pool Dump Valve (1SM001A)

Annunciator 5041-7D NOT AVAILABLE SM SYSTEM DIVISION 1 comes in due to a blown control power fuse deenergizing relay 74-SM1A (1SM001A Bkr Overload relay). The BOP operator will dispatch an Equipment operator to investigate. Technical Specification LCO 3.6.2.4, Action C.1 will be evaluated requiring the restoration of the SPMU subsystem to operable status within 7 days.

4.

Clogged Oil Filter Condensate Booster Pump A Annunciator 5001-1H CLOGGED OIL FILTER CB PUMP 1A will be received. An Equipment Operator will be dispatched to turn the CUNO filter handle several times in an attempt to clear the alarm, but will be unsuccessful.

The SRO will direct the ATC to start a non-running Condensate Booster Pump and secure CB Pump 1A per CPS 3104.01 Condensate/Condensate Booster (CD/CB), section 8.2.2 Starting Additional/Shifting Condensate Booster Pumps.

5.

Inadvertent opening of a SRV Annunciators 5066-5B ADS OR SAFETY RELIEF VALVE LEAKING and 5067-8L SRV MONITORING SYSTEM TROUBLE come in due to SRV 1B21-F041G failing ~ 50 % open. The BOP operator will diagnose and determine the problem is with 1B21-F041G. The SRO will direct the BOP operator to sound the containment evacuation alarm and coordinate with the ATC and attempt to close the SRV IAW CPS 4009.01 Inadvertent Opening Safety/Relief Valve. The SRO will enter and execute CPS 4005.01 Loss of Feedwater Heating and direct the ATC to restore and maintain reactor power at or below the original power level. SRV 1B21-F041G will shut when the first fuse is simulated removed for the associated A solenoid at 1H13-P661.

6.

Failure of DG Fuel Oil Transfer Pump 1A to auto start Annunciators 5060-8C LOW LEVEL DG DAY TANK 1A and 5060-8E TROUBLE DIESEL GEN 1A are received. The BOP will report that the Fuel Oil Transfer Pump (FOTP) failed to auto start. The SRO will direct the BOP to manually start the FOTP. The ATC/BOP will dispatch an operator to DG 1A room to determine the cause of the alarm. The Equipment Operator will report that the alarm is due to low fuel level in the Div 1 DG Day Tank; currently at 45% and lowering/rising based on whether the FOTP running. Annunciators will clear approximately 1 minute after the FOTP has started. The SRO will declare Div 1 DG inoperable and take actions for TS 3.8.1 Action B.

7.

Loss of CY - Rapid Plant Shutdown The scenario starts with the B CY Pump out of service. In this event the shaft shears on the running CY Pump (0CY01PC). The BOP operator will start the A CY Pump and secure the C CY Pump. However, the A CY pump capacity begins to degrade and annunciator 5014-2B Low Press Cycle Cond Xfer Pump Disch Hdr will be received.

Due to the complete loss of CY system pumps, the crew will perform a Rapid Plant Shutdown and attempt to scram the reactor per CPS 3208.01 Cycled / Makeup Condensate (CY/MC).

8.

LOCA / RAT trip / E51-F013 Failure / Loss Div 3 4160V Bus / TAF Blowdown When the unit is scrammed in event 7, the Main Generator will trip on reverse power (normal post-scram response).

When the Generator trips, a series of malfunctions will result in a loss of all high pressure injection sources to the RPV. A LOCA will then commence, resulting in a loss of RPV inventory and causing DW pressure to increase. The LOCA will escalate, causing RPV level to fall to TAF, requiring an emergency depressurization to be performed (ADS fails to automatically initiate).

9.

LPCS Fails To Auto Start / LPCS Injection Valve 1E21F005 Fails to Auto Open at 472 psig RPV pressure The Low Pressure Core Spray Pump will fail to auto start when DW pressure reaches 1.68 psig and will have to be manually started. In addition, 1E21-F005 LPCS Injection Valve will fail to automatically open at 472 psig RPV pressure, requiring the injection valve to be manually opened to recover RPV level above TAF.

ILT 20-1 NRC Exam Scenario 1 Rev. 0 ILT 20-1 NRC Exam Scenario 1 D-1.docx Page 3 of 9 CT Bases Information

1.

[CT-1] Shuts Safety Relief Valves (SRVs) before Suppression Pool temperature reaches 110F.

a)

This critical task was derived from ITS 3.6.2.1 Suppression Pool Average Temperature and EOP-6 Primary Containment Control. Per B3.6.2.1, Average temperature shall be 110°F when THERMAL POWER is 1%

RTP. This requirement ensures that the plant will be shut down at > 110°F. The pool is designed to absorb decay heat and sensible heat but could be heated beyond design limits by the steam generated if the reactor is not shut down. Taking mitigating actions to prevent an unnecessary reactor shutdown is therefore critical.

2. [CT-2] RPV-1.1/TSA-2 Initiate ADS (7 SRVs) within 17.5 minutes of blowdown being required (Rx Level at TAF).

a)

This critical task was derived from OP-CL-102-106 Operator Response Time Master List at CPS and applies during Medium LOCA associated inventory loss rate events, requiring depressurization of the reactor after ADS fails to initiate for any reason. In this scenario, ADS automatic initiation is defeated and a medium sized leak in the lower RPV plenum is initiated (1-2% magnitude). A task is essential to safety if its improper performance or omission by an operator will result in direct adverse consequences or significant degradation in the mitigative capability of the plant. In this instance, depressurization of the reactor is required to allow low pressure ECCS systems to restore RPV water level above TAF and is therefore critical. The 17.5-minute time boundary is based on the CPS Master List of Time Sensitive Actions (TSA 2) which requires ADS initiation within 17.5 minutes after a blowdown is required.

3.

[CT-3] Maximizes ECCS injection by starting the LPCS Pump and opening 1E21-F005 to restore RPV water level above TAF within 10 minutes after RPV level reaches -187.

a)

Although limited low pressure injection will commence as soon as RPV pressure drops below the shutoff head for each of the affected systems, the magnitude of the leak is such that RPV water level will not recover above TAF if Low Pressure Core Spray (LPCS) is not manually initiated. OP-CL-101-111-1001, Strategies for Successful Transient Mitigation, states that available injection sources (RHR, LPCS, HPCS, RCIC, CD/CB/FW) must be maximized in EOP-1 with RPV level below TAF, regardless of RPV pressure.

b)

This critical task was derived from the EOP-SAG Technical Bases which states that following the blowdown, injection into the RPV is maximized to restore RPV water level above TAF. This critical task applies when there are no automatic actions that will restore reactor water level above top of active fuel and failure to perform the task will result in a loss of core cooling via core submergence. The barrier criteria of -187 is selected because EOP-1 directs exiting all EOP flowcharts and entering all SAG flowcharts if RPV level cannot be maintained above -187 (the Adequate Core Conditions specified in EOP-1) in anticipation of core geometry changes. The time limit of 10 minutes was agreed upon between the NRC Chief Examiner and the facility and is considered adequate for a competent operator to complete the task. A task is essential to safety if its improper performance or omission by an operator will result in direct adverse consequences or significant degradation in the mitigative capability of the plant. In this instance, challenging fuel integrity with inadequate cooling would result in a fuel rod perforation. An action that mitigates the event and restores adequate core cooling via submergence is therefore critical.

Appendix D Scenario Outline Form ES-D-1

ILT 20-1 NRC Exam Scenario 1 Rev. 0 ILT 20-1 NRC Exam Scenario 1 D-1.docx Page 4 of 9 Facility: Clinton Power Station Scenario No.: 2 Operating Test No.: 2022-301 Examiners: ____________________________

Operators: ____________________

Initial Conditions:

Mode 2 at ~7%

Weather conditions are calm and clear.

Turnover:

Power ascension is in progress. CPS 3002.01 Heatup and Pressurization is complete up to and including step 8.7.2. CPS 3004.01 Turbine Startup and Generator Synchronization is completed up to and including step 5.2.

Priorities for the shift are as follows:

  • First Priority - Cross-tie 480V Buses 1L & 1M with 1L supplying per CPS 3502.01 480 VAC Distribution.
  • Complete the remaining steps of CPS 3002.01 Heatup and Pressurization, including the following milestones:
  • Power ascension to 10%.
  • Transition to Mode 1.

Critical Tasks:

[CT-1] ATC inserts a manual scram before area temperature reaches max safe in any one area.

[CT-2] Enters and executes blowdown in EOP-1 within 15 minutes of 1TR-CM326 point 12 and 1TR-CM327 point 14 exceeding 140F. (CT-3 can also be satisfied by anticipating blowdown and opening bypass valves per EOP-1.)

Event No.

Malf. No.

Event Type*

Event Description 1

None N-BOP Cross-tie 480V Buses 1L & 1M with 1L supplying 2

None R-ATC Raise power with rods 3

LS06_MALF C-ATC Control Rod Reed Switch Stuck Open 4

YP_XMFTB_4901 Failed C-ATC Stuck IRM F Detector 5

YP_XMFTB_4053 TS-SRO (NEW) NSPS Bus 1A Inverter Trip 6

A05_A02_A0203_5_TVM Steady C-BOP TS-SRO (NEW) RCIC Suppression Pool Level Transmitter Failure - High 7

A11_A02_03_7_TVM 2 C-BOP (NEW) Clogged CW Pump 1C TW Supply Strainer 8

YP_XMFTB_5082 M-All RPV Instrument Line Leak 9

CAM1PR006(A/B/C/D)

TV_VALUE1 = 21-24 mr A11_A03_01_4_TVM 4 A11_A03_02_3_TVM 4 A18_A03_S11 = 1 A18_A03_S10 = 1 A12_A01_07_6_TVM 2 A12_A02_07_6_TVM 2 C-BOP Radiation Monitor fails to isolate VF / Startup VG (N)ormal, (R)eactivity, (I)nstrument, (C)omponent, (M)ajor NEW - Not used on the previous two (2) NRC exams.

ILT 20-1 NRC Exam Scenario 1 Rev. 0 ILT 20-1 NRC Exam Scenario 1 D-1.docx Page 5 of 9 Appendix D Scenario Outline Form ES-D-1 Scenario No.: 2 Operating Test No.: 2022-301 Narrative Summary Event #

Description

10. Cross-tie 480V Buses 1L & 1M with 1L supplying Following shift turnover, the SRO will direct the BOP Operator to cross-tie 480V Buses 1L & 1M with 1L supplying per CPS 3502.01 480 VAC Distribution section 8.1.4 Transferring a 480V Bus: Paralleling Method.
11. Raise power with rods to enter Mode 1 The crew will continue the power ascension to 10% by withdrawing control rods in accordance with Step 8.7.3 of CPS 3002.01 Heatup and Pressurization.
12. Control Rod Reed Switch Stuck Open Annunciator During the attempted withdrawal of the control rod 24-25, a rod position reed switch fails (stuck open) in one channel of the two channel position probe. The ATC will determine which channel is inaccurate and enter substitute position data IAW CPS 3304.02 Rod Control and Information System (RC&IS) Section 8.2.4 Entering Substitute Data. Once substitute position data has been substituted for the control rod with the failed reed switch, the crew will continue the power ascension.
13. Stuck IRM F Detector When the ATC operator attempts to withdraw IRM detectors IAW CPS 3306.01 Source/Intermediate Range Monitors (SRM/IRM), the IRM F detector IN light will remain illuminated. The ATC Operator will inform the SRO, review CPS 3306.01 section 8.2.1 Stuck SRM/IRM Detector and recommends attempting to free the detector by driving it in the opposite direction. This action frees the stuck detector and allows all IRM detectors to be withdrawn when attempted the second time.
14. NSPS Bus 1A Inverter Trip The Div 1 NSPS Inverter DC input breaker will trip resulting in transfer of Div 1 NSPS power supply to the 480V /

120V transformer alternate supply. The SRO will evaluate and enter ITS 3.8.7 Inverters - Operating Required Action A.1 Restore Div 1 inverter to OPERABLE status within 7 days.

15. RCIC Suppression Pool Level Transmitter Failure - High Annunciator 5063-3E Suppression Pool Water Level High is received. The crew will recognize that the RCIC suction source failed to automatically shift to the Suppression Pool. The SRO will direct the BOP to transfer RCIC suction to the Suppression Pool IAW CPS 3310.01 Reactor Core Isolation Cooling (RI) section 8.1.9.2 Shifting RCIC Suction to Suppression Pool. The SRO will enter ITS LCO 3.3.5.3 RCIC System Instrumentation A.1, D.1. and (D.2.1 or D.2.2).
16. Clogged CW Pump 1C TW Supply Strainer Annunciator 5041-3G LOW FLOW CW PUMP 1C BRG SEAL WATER comes in due to CW Pump C seal water flow less than the setpoint (15 gpm). The BOP operator will dispatch an Equipment Operator to investigate. Seal water flow to Circulating Water (CW) Pump 1C cannot be restored. The BOP/ATC operator(s) will closely monitor main condenser vacuum (may enter Loss of Vacuum off-normal) while securing CW Pump 1C and starting CW Pump.
17. RPV Instrument Line leak An RPV instrument line will break resulting in a partial loss of RPV instrumentation, a steam leak in the secondary containment and EOP-8 entry. Secondary containment temperatures will rise requiring a reactor scram. Two areas in secondary containment will exceed Maximum Safe temperature requiring blowdown. The crew may Anticipate Blowdown using bypass valves prior to two areas reaching max safe.
18. Radiation Monitor fails to isolate VF / Startup VG Due to the RPV instrument line leak in the secondary containment, the VF exhaust radiation monitors trend up to the trip isolation set point but fail to actuate VF system isolation and start of VG. Per EOP-8, if either action did not occur automatically, it should be initiated manually (by BOP operator). High VF exhaust radiation is an indication of a break into the secondary containment and high radiation levels may limit access to the secondary containment. VF operation is the preferred method of maintaining a negative secondary containment pressure under emergency conditions since the effluent is processed and discharged through an elevated release point, mitigating the radioactive release and allowing operator access to the secondary containment.

ILT 20-1 NRC Exam Scenario 1 Rev. 0 ILT 20-1 NRC Exam Scenario 1 D-1.docx Page 6 of 9 CT Bases Information

4.

[CT-1] ATC inserts a manual scram before area temperature reaches max safe in any one area.

a)

This critical task was derived from the EOP Technical Bases, and applies when secondary containment temperatures are approaching max safe values. A task is essential to safety if its improper performance or omission by an operator will result in direct adverse consequences or significant degradation in the mitigative capability of the plant. In this instance, the scram reduces the rate of energy production and thus the heat input, radioactivity release, and break flow into the secondary containment. An action that mitigates the event and precludes heat input, radioactivity release, and break flow into the secondary containment is therefore critical.

5.

[CT-2] Enters and executes blowdown in EOP-1 within 15 minutes of 1TR-CM326 point 12 and 1TR-CM327 point 14 exceeding 140F. (CT-2 can also be satisfied by anticipating blowdown and opening bypass valves per EOP-1.)

a)

This critical task was derived from the EOP Technical Bases and applies when secondary containment temperatures exceed max safe values. The time limit of 15 minutes was agreed upon between the NRC Chief Examiner and the facility and is considered adequate for a competent operator to complete the task when blowdown parameters are exceeded. A task is essential to safety if its improper performance or omission by an operator will result in direct adverse consequences or significant degradation in the mitigative capability of the plant. In this instance, the blowdown is required because parameters above the maximum safe operating values in two separate areas is indicative of a wide-spread problem posing a direct and immediate threat to secondary containment, equipment in the secondary containment, and safe operation of the plant. An action that mitigates the event and precludes heat input, radioactivity release, and break flow into the secondary containment is therefore critical.

ILT 20-1 NRC Exam Scenario 1 Rev. 0 ILT 20-1 NRC Exam Scenario 1 D-1.docx Page 7 of 9 Appendix D Scenario Outline Form ES-D-1 Facility: Clinton Power Station Scenario No.: 3 Operating Test No.: 2022-301 Examiners: ____________________________

Operators: ____________________

Initial Conditions:

Mode 1 at ~90% power.

Weather conditions are calm and clear.

CCW Pump A (1CC01PA) is OOS for maintenance. Not expected back this shift.

HPCS Suction is aligned to the Suppression Pool.

Turnover:

Priorities for the shift are as follows:

  • Maintain power at ~90% power throughout the shift.

Critical Tasks:

[CT-1] Close inboard and/or outboard Main Steam Isolation Valves prior to RPV pressure reaching 380psig to prevent exceeding RPV cooldown rate.

[CT-2] Manually inject with HPCS prior to Reactor Water Level reaching TAF.

Event No.

Malf. No.

Event Type*

Event Description 1

HP17FSREM04REMIN Pulled N-BOP TS-SRO (NEW) Swap HPCS Suction to RCIC Storage Tank, Perform HPCS Valve Operability Test, Suppression Pool Suction Valve (1E22-F015) fails closed 2

N/A R-ATC EPR for Grid Load Reduction 3

YFFWPPSS_13 C-BOP (NEW) MC Pump B coupling failure 4

S_K603A 4 OPEN SLOW C-ATC A RR Flow Control Valve (FCV) drifts Open 5

A01_A08_A01_1 I-ATC Hotwell Overflow Controller Failure 6

ed_ek20=true C-BOP TS-SRO Trip of ERAT SVC 7

YP_XMFTB_4063 YPXMALSE_588 100%

RAT_B_Differential A02_A05_02_11_TVM M-All Generator Trip / Turbine Trip / Bypass Valve 1 sticks open / RAT Failure after MSIVs closed /

LOCA 8

YPXMALSE_510 0.1%

YP_XMFTB_4101 YFRIPPSS hp10con45fsp=True C-BOP RCIC failure / HPCS Pump fails to auto start /

HPCS Injection Valve fails to auto open (N)ormal, (R)eactivity, (I)nstrument, (C)omponent, (M)ajor NEW - Not used on the previous two (2) NRC exams.

ILT 20-1 NRC Exam Scenario 1 Rev. 0 ILT 20-1 NRC Exam Scenario 1 D-1.docx Page 8 of 9 Appendix D Scenario Outline Form ES-D-1 Scenario No.: 3 Operating Test No.: 2022-301 Narrative Summary Event #

Description

19. Swap HPCS Suction to RCIC Storage Tank, Perform HPCS Valve Operability Test, Suppression Pool Suction Valve (1E22-F015) fails closed The scenario begins with the HPCS Pump suction aligned to the Suppression Pool IAW CPS 3309.01 High Pressure Core Spray (HPCS). The BOP operator will be directed to swap HPCS Suction back to the RCIC Storage Tank IAW CPS 3309.01 High Pressure Core Spray (HPCS) section 8.1.7.2 Shifting HPCS Suction to RCIC Storage Tank.

When this task has been completed, the BOP operator will be directed to perform CPS 9051.02 HPCS Valve Operability Test. During performance of CPS 9051.02, when the control switch for 1E22-F015 HPCS Suppr Pool Suction Valve is positioned to open, annunciator 5062-8E HPCS OUT OF SERVICE comes in due to trip of the circuit breaker for 1E22-F015 HPCS Suppr Pool Suction Valve. CPS 3309.01 High Pressure Core Spray (HPCS) NOTE for section 8.1.7 states in part, Per ITS LCO 3.5.1/2, HPCS must be capable of taking a suction from the Suppression Pool. The SRO will declare HPCS INOPERABLE and enter T.S. 3.5.1 Required Actions B.1 Verify by administrative means RCIC System is OPERABLE when RCIC is required to be OPERABLE, and B.2 Restore HPCS System to OPERABLE status within 14 days. The SRO will also declare 1E22-F015 INOPERABLE and enter T.S. 3.6.1.3 Primary Containment Isolation Valves (PCIVs) Required Action A.1 Isolate the affected penetration flow path (4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />) and A.2 Verify the affected penetration flow path is isolated (once per 31 days).

20. EPR for Grid Load Reduction The Transmission System Operator (TSO) will call the MCR and direct CPS to lower Generator output by 80 MWe to mitigate degraded grid conditions. IAW OP-CL-108-107-1002 Degraded Grid Actions, the SRO will direct performance of an Emergency Power Reduction. The ATC will lower power by 80 MWe within 15 minutes of the TSO request.
21. MC Pump B coupling failure Annunciator LOW PRESS MAKE-UP COND XFER PUMPS DISCH HDR (5014-2C) comes in due to the Make-Up Condensate Transfer Pump 1B (0MC01PB) shaft shear. The BOP Operator will dispatch an Equipment operator to investigate. Upon the report of a shaft shear, the BOP operator will stop the failed pump and start the standby pump per CPS 3208.01 Cycled/Makeup Condensate Section 8.1.1.
22. A RR Flow Control Valve (FCV) drifts Open The A RR Flow Control Valve slowly drifts open causing reactor power to rise and requires the ATC to perform an emergency shutdown of the A RR Hydraulic Power Unit to stop further RR FCV movement. The crew will enter and execute CPS 4008.01 Abnormal Reactor Coolant Flow. The crew will evaluate core thermal limits by demanding a 3D Monicore Case to ensure core thermal limits are within TS limits. The crew will also evaluate RR loop flow mismatch to ensure operation within ITS 3.4.1 Recirculation Loops Operating limits.
23. Hotwell overflow controller failure Annunciator 5014-4B Not Fully Closed Cdsr Emerg O/Flow Vlv 1CD020 is received and lowering hotwell level will be observed. The ATC will diagnose the failure of the Hotwell Overflow to CY Cond Storage Tank 1LC-CD057A controller and will take manual control per CPS 3104.01 Condensate / Condensate Booster (CD/CB) section 8.6.2 Abnormal Condenser Hotwell Level LOW Level.
24. Trip of ERAT SVC Annunciator 5011-8E ERAT SVC TRIP comes in due to a trip of the ERAT Static VAR Compensator for unknown reasons. The ARP will direct the BOP/ATC to dispatch an Equipment Operator to investigate, the BOP to place the ERAT SVC control switch to OFF and to transfer the 1A1 bus to the RAT. The SRO will enter CPS 4200.01 Loss Of AC Power, ensure/make necessary notifications to the Power Team and TSO (Ameren) and will declare the 138KV Offsite Source inoperable and take actions for TS 3.8.1.
25. Generator Trip / Turbine Trip / Bypass Valve 1 sticks open / RAT Failure after MSIVs closed The Main Generator will trip resulting in a Turbine trip and reactor scram. The Steam Bypass Valves will initially open as expected following the Main Turbine trip, but #1 Bypass Valve will remain open causing RPV pressure to decrease. The crew will diagnose the failure of the Bypass Valves to control Reactor pressure and will shut the MSIVs to prevent exceeding the 100°F/hr cooldown rate limitation and to prevent flooding the MSLs with feedwater.

Shutting the MSIVs will eliminate the RFPTs as a high pressure injection source. A RAT trip will occur due to a fault when the MSIVs are closed (not related), resulting in a loss of BOP power and eliminating the FW/CD/CB system as a feed source. Finally, an unisolable RCS leak occurs in the DW, causing DW pressure to exceed 1.68 psig.

26. RCIC failure / HPCS Pump fails to auto start / HPCS Injection Valve fails to auto open The RCIC pump shaft will fail if automatically or manually initiated. The HPCS Pump will fail to automatically start and 1E22F004 HPCS Injection Valve will fail to automatically open, requiring the MCR to manually start the HPCS Pump and open the injection valve for inventory control and to avoid the necessity for performing a blowdown when RPV level reaches TAF.

CT Bases Information

ILT 20-1 NRC Exam Scenario 1 Rev. 0 ILT 20-1 NRC Exam Scenario 1 D-1.docx Page 9 of 9

6.

[CT-1] Close inboard and/or outboard Main Steam Isolation Valves prior to RPV pressure reaching 380psig to prevent exceeding RPV cooldown rate.

a)

The critical task was derived from ITS 3.4.11 RCS P/T Limits. Per B3.4.11, the consequence of violating the LCO limits is that the RCS has been operated under conditions that can result in brittle failure of the RCPB, possibly leading to a nonisolable leak or loss of coolant accident. Taking mitigating actions to prevent exceeding the cooldown rate limitation is therefore critical. In this case, these mitigating actions are accomplished by closing the inboard and/or outboard Main Steam Isolation Valves prior to RPV Pressure reaching 380#.

7.

[CT-2] Manually inject with HPCS prior to Reactor Water Level reaching TAF.

a)

This critical task was derived from the EOP-SAG Technical Bases and applies when there are no automatic actions that will maintain reactor water level above top of active fuel and failure to perform the task will result in either an automatic or manual depressurization. A task is essential to safety if its improper performance or omission by an operator will result in direct adverse consequences or significant degradation in the mitigative capability of the plant. In this instance, challenging the plant with an unnecessary blowdown would result in an unnecessary transient and risks associated with that transient. An action that mitigates the event and precludes blowdown is therefore critical. For this scenario, manual injection with HPCS is the only viable method of maintaining water level above TAF.

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