Shut Down Cooling Flashcards
Prior to placing SDC in service, what is done to prevent Spurious Group 5 isolations?
MO 2(3)-1301-4 should be closed and should be opened again after SDC is removed from service
What can cause spurious group 5 isolations when starting SDC?
Process noise from the SDC system. avoided by closing 1301-4 valve
When SDC is injecting into a RR Loop, when affect will this have on the RPV level instrumentation?
SDC injection into a RR loop will cause Fuel Zone Lvl indicator on that loop to read high.
As a result, should use Fuel Zone Lvl indicator on loop opposite to SDC injection or OTHER available level indicator
Why is SDC Pp discharge vlv opening speed opened slowly when placed in service?
When Mod. Temp >135F, open disch vlv slowly (20-25 sec) to minimize thermal stress on LPCI/Recirc piping tee, and to prevent flashing RBCCW.
What adverse affects can quickly placing SDC into service and oping valves have?
Thermal stress on LPCI/RR Piping Tee and Flashing RBCCW when quickly opening SDC Pp Discharge vlv
What conditions need to be avoided w/ SDC operating with no Recirc Pumps on? How?
RPV Stratification - If Rx SHUTDOWN and RR Pps not running and less than full Rx flow through two SDC loops, THEN RAIS level to at or above +48in
+48IN provides NATURAL CIRCULATION through moisture separator and prevents stratifications
Monitor RPV metal temps once per hour
What is done to prevent RPV Stratification with no RR Pps running?
Natural Circ via raising water level to +48IN
OR
SDC Pp Discharge vlv opened to max specified or until discharge pressure drops to 100psig
How are teh RBCCW and SDC trains lined up durign SDC Startup?
W/ Rx Temp >212F MAXIMIZE RBCCW Flow to SDC Hx - 2 RBCCW trains
What limitations are placed on the RBCCW Hx Outlet Vlv?
Max opening:
11 seconds w/ one SDC Hx valved in
16 seconds w/ two SDC Hx valved in
<42A on RBCCW Pp Motors or >50psig RBCCW Pp discharge header pressure w/ 3 Hx in service
Why is Rx cooldown w/ only 1 RBCCW train in service?
can result in inadequate cooling supplied
What is the valve sequence for SDC startup?
Initial: MO 3704 (RBCCW Outlet) opened max while throttling SDC Pp discharge vlv
At Rx Water <280F: 3704 may be throttled w/ Unit Sup Permission
At Rx Water <212F - cooldown rate controlled by throttling 3704 w/ SDC Pp discharge full open
AT NO POINT SHALL RBCCW DISCHARGE EXCEED 200F
What SHALL NOT BE DONE if Rx Water temp >212F?
DO NOT PLACE SDC IN SERVICE W/ RBCCW VALVED OUT
When is Primary Containment Integrity Requried Per TS?
Mode 3 >212F or Modes 1 and 2
What is pressure limitation for admitting Rx water to SDC?
RPV pressure <119.9psig analytically, 100.9psig setpoint
If a RR pp is not running, what should be done prior to admitting SDC to that loop?
Close EITHER suction or discharge vlv to prevent short cycling
