Steam Generating/SGWLC/Blowdown Flashcards
What side of the SG are most of the FW J Tubes?
- 80% are on the Hot Leg side of U-Tubes
What do the J tubes help to prevent?
- Maintain ring full to minimize water Hammer when AFW initiates
What is P-14 permissive?
- SG Hi HI Lvl at 67% on 1 SG (2/3)
What will P-14 permissive cause?
- Turbine Trip
- MFP Trip
- FWI
What enables AMSAC?
- > 40% Power (C-20, 2/2 Turbine first stage Impulse #)
What causes an AMSAC signal?
- FW flow < 25% (3/4 Feed flow)
What will AMSAC actuate?
- All 3 AFW Pumps
- Trips Main Turbine (30 Sec)
When do DCR-310-340 (BD isolation valves) automatically isolate?
- Phase A
- High Rad: R-19 (Sampling)
- High Rad: R-24 (Treatmnt)
- High Level in Flash Tank
- AFW Flow Conservation (MDAFP starts)
- TDAFP Start
When do BD sample isolation valves (DCR-301-304) automatically close?
- High Rad
- Phase A
What actuations does a high rad signal from R-19 cause? ***
- Closes BD Isolation DCRs 310-340
- Closes DRV-350 SGBD Flashtank to TRS
- Closes BD Sampling DCRs 301-304
- Override available
What actuations does a high rad signal from R-24 cause?
- Trips SGBD Treatment Pump
- Closes BD Isolation DCRs 310-340
- Closes DRV-350 SGBD Flashtank to TRS
- Closes BD Sampling DCRs 301-304
- Override available
Control air header pressure is lowering at a fast rate. At 80 psi, the reactor is manually tripped, and header pressure continues to lower. What will happen to the air reg valves in the BD system if pressure continues to lower?
- All air reg valves on BD system will isolate on loss of ctrl air
- DRV-350/352
- BD isolation valves
- BD Flow Ctrl Valves
- BD Sample Valves
What are the BDFT level alarms?
- High 75% alarms and closes BD isolation valves
- Low 55% alarms and trips BD treatment pump
- Low 53% alarms and closes DRV-350 (only in auto)
- Extreme low 51.5% alarms
What does SGWLC maintain?
- SGWLC maintains SG Narrow Range level at 43.8% for all power levels.
What is the dominant control for SG Level? ***
- Level Dominant (43.8%)
- Steam Generator Level overrides Feed flow/Steam Flow mismatch over time, level is a lag signal*
What causes a Steam Line Isolation (SLI)? ***
- Cnt # High-High at 2.8# (2/4)
- SG # low < 500# (1/1 on 2/4 SG)
- High Stm flow with P-12 (1.42E6/1.6E6) (1/2) on 2 SG
What is the definition of density compensation?
- converts volumetric flow rate of steam to mass flow rate for input into SGWLC circuit. (Left 2 Channels ctrl SG lvl)
Where do we measure SG Level?
- SG Downcomer
What is swell caused by? ***
- an increase in steam flow (which will cause an increased indication of SG lvl in the downcomer due to decreased SG #) (More intense boiling)
What is shrink caused by?
- reduction in steam flow (which will cause an decreased indication of SG lvl in the downcomer due to a rise in SG#) (Less intense boiling)
In MODES 1 and 2, the reactor is critical and thus has the potential to produce maximum THERMAL POWER. Thus, to ensure that the assumptions of the accident analyses remain valid, all RCS loops are required to be OPERABLE and in operation in these MODES to prevent ________ and _________.
- DNB
2. Core Damage
What constitutes an OPERABLE RCS Loop?
- An OPERABLE RCS loop consists of an OPERABLE RCP in operation providing forced flow for heat transport and an OPERABLE SG
With the plant in MODE 3 and the CRDM’s energized, how many RCS loops are required to be operable?
- When in MODE 3 with CRDM’s energized, 2 RCS loops shall be OPERABLE
What is the maximum permissible RCS to SG leakage? (TS 3.4.13)
- 150 gpd primary to secondary LEAKAGE through any one steam generator (SG)
Basis: Limit release to atmo outside ctmnt based on 10CFR100
If the steam flow indication fails high to your flow controller, what will happen the FRV?
- The FRV will go open because Feed Flow will want to match Steam Flow
If the steam flow indication fails low to your flow controller, what will happen the FRV?
- The FRV will go closed because Feed Flow will want to match Steam Flow
If the feed flow indication fails low to your flow controller, what will happen the FRV?
- The FRV will go open because Feed Flow will want to match Steam Flow
If the feed flow indication fails high to your flow controller, what will happen the FRV?
- The FRV will go closed because Feed Flow will want to match Steam Flow
With the plant in MODE 3 and the CRDM’s are not energized, how many RCS loops are required to be operable?
- When in Mode 3 with CRDMs not energized, 2 RCS loops shall be OPERABLE with one in operation
What, with respect to RCS Loops, is required to be operable in Mode 4? (TS 3.4.6)
- Two loops consisting of any combination of RCS loops and residual heat removal (RHR) loops shall be OPERABLE, and one loop shall be in operation.
Basis:
Accidental boron dilution event
What does TS 3.4.7 (RCS Loops Mode 5) require?
- One residual heat removal (RHR) loop shall be OPERABLE and in operation,
AND - a. One additional RHR loop shall be OPERABLE;
OR
b. The secondary side water level of at least two steam generators (SGs) shall be above the lower tap of the SG wide range level instrumentation by ≥ 420 inches.
Basis:
Accidental boron dilution event
Unit 1 was operating at 100% power when a loss of main feedwater occurs to a single SG due to the failure of the controlling feedwater flow instrument.
A valid indication on the affected SG “Flows / Level / Pressure” recorder for this failure would be a rapidly lowering SG level and a?
- high feedwater flow indication on the feedwater flow pen.
What will cause a FWI?
- SG High-High level (P-14) (67% NR 2/3 on 1 SG)
- SI
- Rx trip (P-4) with low Tavg (Tavg < 554°F on 2/4 loops)
What is the reactor trip associated with SG Lvl Low
15% (U1) 26% (U2) 1/2 channels on 1/4 SGs w/ SF/FF Mismatch 0.71M (U1) 1.47M (U2) 1/2 channels on the same SG
What happens on a SG Lvl Low-Low
5% (U1) 22% (U2) 2/3 channels on 1/4 SGs
- Rx Trip
- Auto start of MDAFP (1 SG)
- Auto start of TDAFP (2 SGs)
What are the SG Pressure and Temperature TRM limits
Primary and secondary temps in a SG must be greater than 70 deg when the pressure of either primary or secondary is greater than 200# to prevent brittle fracture (restore in 30 mins)
