ML22236A020
| ML22236A020 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 05/14/2021 |
| From: | Chuck Zoia NRC/RGN-III/DRS/OLB |
| To: | Exelon Generation Co |
| Zoia C | |
| Shared Package | |
| ML20136A310 | List: |
| References | |
| Download: ML22236A020 (3) | |
Text
Scenario Outline Facility:
Dresden Generating Station Scenario No.:
2021-301 ILT-N-2 Op-Test No.: 2021-301 Examiners Operators
/ crew position
/ ATC
/ BOP
/ CRS Initial Conditions:
Unit 2 is at 85% Power.
Site is under a high winds advisory due to inclement weather.
Turnover:
A Condensate/Condensate Booster Pump is experiencing high vibrations and needs to be removed from service for maintenance once power is lowered to 82% per DGP 03-01, Power Changes, step G.4.
Critical Tasks:
- 1. If the RPV level trend is not reversible with an RPV injection source lined up with a pump running, initiate emergency depressurization by opening 5 ADSVs with RPV water level between the Top-of-Active Fuel and the Minimum Steam Cooling RPV Water Level or within 2 1/2 minutes after TAF is reached, whichever is later.
- 2. Per DEOP 100, RPV Control, with automatic ADS timer initiated, inhibit ADS before an automatic actuation occurs.
Event No.
Malf.
No.
Event Type*
Event Description #
1 NONE R
ATC Lower Power with flow 2
NONE N
BOP Secure RFP and C/CB Pump 3
HPRMBRKP C/T BOP / CRS HPCI Isolation due to Steam Leak 4
RDPPBTRP C/T ATC / CRS CRD Pump Trip 5
CSP501B C/T BOP / CRS Core Spray System Low Pressure 6
X10 C
F41 M
Team Recirc Leak in DW - Manual Scram 8
CS2AFTC CSLAUPPA C
BOP Core Spray Pump Fails to Auto Start 9
RLMRASP RLMRBSP M
Team Loss of Feed - Emergency Depressurization on Level
- (N)ormal, (R)eactivity, (I)nstrument, (C)omponent, (M)ajor, (T)ech Spec
- (New) - Event not used on previous 2 NRC Exams, (Pre) - Event used on previous 2 NRC Exams
Scenario Outline Facility:
Dresden Generating Station Scenario No.:
2021-301 ILT-N-3 Op-Test No.: 2021-301 Examiners Operators
/ crew position
/ ATC
/ BOP
/ CRS Initial Conditions:
Unit 2 is at 72% Power.
U2 Isolation Condenser is OOS for 2-1301-3 valve motor replacement.
Turnover:
During initial power ascension following a refuel outage, 345kV Bus Tie 4-5 CB tripped. Repairs have been completed and the 345kV Switchyard is ready to be returned to a normal lineup. Once restored, continue on with power ascension to raise reactor power to 90% using recirc flow per QNE guidance.
Critical Tasks:
- 1. With reactor scram required and reactor not shutdown, act per DEOP 400-5, Failure to Scram, to reduce power by inserting negative reactivity before Torus temperature reaches 110oF.
- 2. Once DEOP 400-5, Failure to Scram, is entered -AND-reactor power is > 6% -AND-reactor level is > the Top-of-Active Fuel - AND-drywell pressure is > 2 psig or an ERV is open -AND-torus temperature is > 110o F, terminate and prevent injection (with exception of SBLC and CRD) into the RPV prior to exceeding Heat Capacity Temperature Limit (HCTL).
Event No.
Malf.
No.
Event Type*
Event Description #
1 NONE N
BOP Restore 345kV Bus Tie 4-5 Circuit Breaker 2
NONE R
ATC Raise Reactor Power using Recirc Flow 3
RR02A C/T ATC / CRS Recirc Pump Speed Controller Failure 4
RADRBVAH VGDSTBYA VGDPRIMA VGDSTRTA C/T BOP / CRS RB Vent Rad Monitor Fails Upscale, SBGT Fails to Auto Start 5
T50 C
BOP Stator Water Cooling Pump Trip 6
CIGP1I M
Team Spurious Group 1 - SCRAM 7
RDHLVFPA RDHLDEGA RDHLVFPB RDHLDEGB M
Team Hydraulic ATWS 8
SCRLFVAD SCRLFVBD C
ATC SBLC Relief Valve Fails Open
- (N)ormal, (R)eactivity, (I)nstrument, (C)omponent, (M)ajor, (T)ech Spec
- (New) - Event not used on previous 2 NRC Exams, (Pre) - Event used on previous 2 NRC Exams
Scenario Outline Facility:
Dresden Generating Station Scenario No.:
2021-301 ILT-N-4 Op-Test No.: 2021-301 Examiners Operators
/ crew position
/ ATC
/ BOP
/ CRS Initial Conditions:
Unit 2 is in Mode 2. Reactor Power is stable at 7%
Turnover:
Per DGP 01-01, Unit Startup, step G.57, stop rejecting to the Condenser with RWCU. Once complete, continue raising power to 10% per DGP 01-01 in preparation to put the Mode Switch in RUN.
Critical Tasks:
- 1. When RPV water level cannot be determined by multiple direct or indirect indications as defined by DEOP 0010-10, exit DEOP 100 and enter DEOP 400-1, RPV Flooding before DW radiation levels exceed 100 R/hr.
- 2. When conditions are met per DEOP 400-1, RPV Flooding, the minimum number (2 ADSVs) of available ADSVs for RPV depressurization are opened before DW radiation levels exceed 100 R/hr to allow RPV injection with high capacity, low pressure sources (Condensate/Feedwater, LPCI and/or CS).
- 3. Following RPV depressurization during non-ATWS RPV Flooding, and before DW radiation levels exceed 100 R/hr, maximize injection with high capacity, low pressure sources (Condensate/Feedwater, LPCI and/or CS) and do not divert available RPV injection flow paths until the RPV is flooded to the Main Steam Lines.
Event No.
Malf.
No.
Event Type*
Event Description #
1 NONE N
BOP Secure Rejecting to Condenser with RWCU 2
NONE R
ATC Raise Power with Rods 3
ADS3ESD C/T BOP / CRS ERV Spurious Open 4
WTPPDSH1 HWWTPPDSH(1)
HWWTBPMP(1)
C BOP Degraded TBCCW Pump 5
NII17POT B15 I/T ATC / CRS IRM Fails Upscale - Partial Half Scram 6
NVM100BP M
TEAM Medium Range Level Reference Leg Leak, Rise in DW Press - Scram 7
B12 C
NVM100AP NVM129AP NVM106AP/BP NVML112P M
TEAM Loss of Level Indication - RPV Flooding
- (N)ormal, (R)eactivity, (I)nstrument, (C)omponent, (M)ajor, (T)ech Spec
- (New) - Event not used on previous 2 NRC Exams, (Pre) - Event used on previous 2 NRC Exams