ML21348A745
| ML21348A745 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  (DPR-044, DPR-056) |
| Issue date: | 12/03/2021 |
| From: | Exelon Generation Co LLC |
| To: | Thomas Setzer Operations Branch I |
| Setzer T | |
| Shared Package | |
| ML21263A160 | List: |
| References | |
| CAC 000500 | |
| Download: ML21348A745 (7) | |
Text
N/A N/A N/A N/A N/A N/A N/A N/A N/A 12/2/21 12/2/21
Appendix D Scenario Outline ES-D-1 2021 NRC Re-Exam Scenario #1 D-1 Rev 0 Simulation Facility PBAPS Scenario No. #1 Op Test No. 2021 NRC Re-Exam Examiners Operator ________________ CRS (SRO)
________________ URO (ATC)
________________ PRO (BOP)
Scenario Summary The scenario begins with the reactor at approximately 95% power with no equipment out of service. The B loop of RHR is operating in Torus Cooling. Two control rods (38-07 and 34-07) have been partially inserted for testing and are ready to be withdrawn.
Following shift turnover, the crew will secure Torus Cooling on the B loop of RHR.
While securing the lineup, a fire will develop in the D HPSW pump. The crew will secure the D HPSW pump and dispatch the Fire Brigade. The CRS will declare the D HPSW pump inoperable per T.S. 3.7.1.A.
Once the technical specification declaration has been made, the crew will withdraw control rods to their full out position. Control Rod 38-07 will be stuck. The crew will perform the actions of SO 62.1.A-2 to raise drive water pressure to unstick the control rod.
Once drive water pressure has been restored to normal, a steam leak will develop in the Secondary Containment from the HPCI steam piping. HPCI room temperatures will rise and require entry into T-103, Secondary Containment Control. The PRO will isolate the steam leak by closing the HPCI Steam Supply Valve. The CRS will declare HPCI inoperable per T.S. 3.5.1.C.
Once the HPCI steam leak has been isolated and the appropriate tech spec call has been made, the crew will receive alarms for high vibrations on the B RFP.
The crew will check vibration levels and determine the B RFP is required to be secured. The crew will place the B RFP in standby per SO 6D.2.A-2.
While the crew is securing the B RFP, a steam leak will occur in the drywell.
Drywell pressure will rise and the crew will enter OT-101, High Drywell Pressure, and attempt to isolate the leak. A vacuum breaker will fail open, causing a loss of suppression function of the containment. When drywell pressure reaches 1.2 psig, the crew will perform a GP-4 shutdown.
Seven control rods will fail to fully insert, requiring the crew to enter T-117, ATWS RPV Control. The crew will bypass ADS and perform alternate actions to insert the remaining control rods. All control rods can be manually inserted.
Drywell pressure will continue to rise and the crew will enter T-102, Primary Containment Control, and initiate containment sprays to control drywell pressure.
The scenario may be terminated once drywell sprays are in service and RPV parameters are being controlled.
Appendix D Scenario Outline ES-D-1 2021 NRC Re-Exam Scenario #1 D-1 Rev 0 Initial Conditions IC-14 95% Power Turnover Unit 2 is at 95% power with no equipment out of service. HPCI has been secured from a test run and is aligned for autostart. B loop of RHR is in Torus Cooling. Control Rods 34-07 and 38-07 have been partially inserted for testing.
Critical Tasks Critical Task 1: Isolate the steam leak prior to a Secondary Containment Temperatures in a second area reach the Maximum Safe Limit.
Critical Task 2: Insert control rods to shutdown the reactor during a failure to scram.
Critical Task 3: Initiate containment sprays prior to drywell pressure exceeding the PSP Limit.
Appendix D Scenario Outline ES-D-1 2021 NRC Re-Exam Scenario #1 D-1 Rev 0 Event No.
Malfunction No.
Event Type*
Event Description 1
See Scenario Guide N
PRO CRS Secure Torus Cooling 2
See Scenario Guide C
TS PRO CRS Fire in B HPSW Pump 3
See Scenario Guide R
URO CRS Withdrawing Control Rods 4
See Scenario Guide C
URO CRS Stuck Control Rod 5
See Scenario Guide C
See Scenario Guide C
See Scenario Guide M
ALL Steam Leak in the Drywell 8
See Scenario Guide C
ALL Low Power ATWS
- (N)ormal, (R)eactivity, (I)nstrument, (C)omponent, (M)ajor, (TS) Tech Spec
Appendix D Scenario Outline ES-D-1 2021 NRC Re-Exam Scenario #2 D-1 Rev 0 Simulation Facility PBAPS Scenario No. #2 Op Test No. 2021 NRC Re-Exam Examiners Operator ________________ CRS (SRO)
________________ URO (ATC)
________________ PRO (BOP)
Scenario Summary The scenario begins with the reactor at approximately 4-5% power during a reactor startup.
Following shift turnover, the crew will perform ST-O-003-450-2, Scram Discharge Vent and Drain Valve Functional Test. The URO will cycle the Scram Discharge Valves closed, then back open per the surveillance procedure. Once completed, the crew will continue the reactor startup by withdrawing control rods until 3 bypass valves are open.
While withdrawing Control Rods, a spurious Rod Worth Minimizer rod block will occur. The crew will perform the alarm response and re-initialize the RWM. The fault will clear once the system is initialized.
Once the RWM has been initialized, a trip of the A Instrument Air Compressor will occur. A Instrument Air header pressure will lower. The crew will enter ON-119, Loss of Instrument Air, start the backup air compressor, and cross-connect the air headers to restore instrument air pressure.
Once instrument air pressure has been restored, a spurious start of the RCIC turbine will occur. The crew will respond to trip RCIC and the CRS will declare RCIC inoperable per T.S. 3.5.3.A.
After RCIC has been tripped and the technical specification declaration has been completed, a loss of continuity will occur on the B SBLC squib valve. The CRS will declare the B SBLC pump inoperable per T.S. 3.1.7.B.
Once the technical specification declaration has been completed, C APRM will fail upscale. The crew will perform the alarm response and bypass the C APRM.
After the D APRM has been bypassed, a rupture in the Torus will occur. Torus water level will begin to lower. The crew will enter T-102, Primary Containment Control, and align injection sources to attempt to restore Torus level. Torus water level will continue to lower, requiring the crew to scram the reactor. The reactor will fail to scram. The crew will initiate ARI to shutdown the reactor. EHC pumps will trip, requiring the crew to control RPV pressure with SRVs.
Torus water level will continue to lower and the crew will perform an RPV Blowdown. One ADS valve will fail to open, requiring the crew to open an additional SRV.
The scenario may be terminated when an RPV blowdown is in progress and plant parameters are being controlled.
Appendix D Scenario Outline ES-D-1 2021 NRC Re-Exam Scenario #2 D-1 Rev 0 Initial Conditions IC-9 4-5% Power Turnover Unit 2 is at 4-5% power during a reactor startup.
Critical Tasks Critical Task 1: Initiate ARI to shutdown the Reactor within 10 minutes of the failure of the Mode Switch and Scram Pushbuttons.
Critical Task 2: Perform an RPV blowdown before RPV water level lowers below 7.
Appendix D Scenario Outline ES-D-1 2021 NRC Re-Exam Scenario #2 D-1 Rev 0 Event No.
Malfunction No.
Event Type*
Event Description 1
See Scenario Guide N
URO CRS Perform SDV Functional Test 2
See Scenario Guide R
URO CRS Continue Reactor Startup 3
See Scenario Guide I
See Scenario Guide C
PRO CRS Instrument Air Compressor A Trip 5
See Scenario Guide I
TS PRO CRS RCIC Spurious Start 6
See Scenario Guide TS CRS B SLC Squib Valve Loss of Continuity 7
See Scenario Guide I
URO CRS D APRM Fails Upscale 8
See Scenario Guide M
ALL Torus Water Leak 9
See Scenario Guide I, MC ALL ATWS (ARI Functional) 10 See Scenario Guide C
URO CRS EHC Pump Trip 11 See Scenario Guide I
URO CRS ADS Valve Fails to Open
- (N)ormal, (R)eactivity, (I)nstrument, (C)omponent, (M)ajor, (TS) Tech Spec