Rapid Plant Shutdown

Question 1

What are the recommended shutdown rates based on RCS leakage?

Answer 1

Less than 50 gpm - 0.5 to 5% per min

Greater than 50 gpm - 5 to 10% per min

Question 2

What are the runbacks specified in RPSD?

Answer 2

Question 3

What RT is performed early in RPSD if RCS leak or steam leak inside RB?

Answer 3

RT-9 (Maximize RB Cooling)

Question 4

What actions are specified in RPSD if necessary to maintain makeup tank level?

Answer 4

Open BWST outlet and minimize/isolate L/D

Question 5

What actions are taken if desired to stop downpower above final ULD setpoint?

Answer 5

SG/RX demand to hand per Exhibit 1

Question 6

What power level is specified in RPSD for RCP trip?

Answer 6

Continue power reduction to 60 - 65% power and trip HD pump associated with tripped RCP. (Step 7)

Question 7

When are heater drain pumps tripped, what actions are required, and what power is specified in note that HD pumps can be maintained running?

Answer 7

HD pumps are tripped, heater drain tank levels maintained and low level condenser sprays opened when < 65% power.

The note specifies HD pumps can be maintained running down to 50% power and securing them can reduce sodium buildup in the secondary.

HD pumps auto trip at 75# and 42” in HD tank.

Question 8

When is zinc injection secured?

Answer 8

< 90% power

Question 9

When do the MFW block valves close and what is monitored? What actions are taken if they do not operate properly?

Answer 9

MFW Block valves close at approximately 45% FW loop demand (2.5 MPPH).

MFP measured variable monitored to ensure 60 to 80 psid is maintained, FW23 and FW27 (MFW valve control out LPA/B) are monitored that they track together and lower with power reduction, and FW19/20 (MFW flow error) are monitored to ensure remain near zero.

If MFW blocks are closed and FW control problems occur go to heat transfer upset. If DP not controlled 60 to 80 psid then place associated MFP in hand and ctrl discharge pressure 1050 - 1150 psig.

Question 10

Why is ULD lowered to 330 MW following runback to 40% (360 MW)?

Answer 10

To prevent trip on loss of turbine bypassed alarm from recurring.

Question 11

When are plant auxiliaries transferred?

Answer 11

If turbine will be taken offline and power < 50%

If SU1 unavailable and SU2 not degraded, A-1/A-2/H-1/H-2 busses are removed from PTL to allow auto transfer when plant is tripped. (U2 should place all their breakers for SU2 in PTL if mode 1-4 or check MVA loading if in mode 5,6 or defueled)

Question 12

What constitues SU2 xfmr as degraded and what actions are taken for plant auxiliaries based on its availability?

Answer 12

If SU2 degraded, vital buses are tied on to the diesels and based on attachment E (XFMR loading restrictions) non-vitals can be transferred.

If SU2 not available, DGs are aligned to vital buses.

Question 13

What actions are taken at Lo Level Limits to continue downpower < 20%

Answer 13

FW demands to hand and demanded to zero and reactor demand to hand.

If turbine only will be shutdown lower power to 10 to 12% with reactor demand.

Question 14

What actions are taken just prior to tripping the reactor?

Answer 14

Turbine to op auto or manual, adjust mvars within 50 MVARs of 0, header pressure setpoint to 45, and then trip RX.

Question 15

What actions are taken for the MFPs with small SG tube leak?

Answer 15

Open FW pump discharge crosstie (CV-2827), lower speed on the bad MFP and trip it and place MFP recirc valve in hand and close.

Question 16

What actions are required per Exhibit 2 for rapid plant shutdown with ICS major stations in hand?

Answer 16

If not on low level limits -> Lower FW demands (normally 5%) in increments followed by rod insertion (Tave 577 - 581) and adjust turbine load if in manual to maintain 870 - 920 psig.

If ON LL Limits, ensure FW demands at minimum and insert rods to lower power and maintain header pressure.

If CRD withdrawal desired, ensure power band provided.

Question 17

What actions are required by Exhibit 3 for MFP trip with ICS major stations in hand? (Used > 60%)

Answer 17

1) Initiate continuous rod motion
2) Perform initial actions per loss of SG feed AOP for MFP trip
3) When within capacity of one pump (60 - 70% TAve stabilizes) adjust FW demands and insert rods as needed to stabilize Tave 577 - 581 and Delta Tc -2 to 2 degF
4) Adjust FW demands to lower FW and insert rods until approximately 40%.

Question 18

What actions are required per Exhibit 4 for RPSD with Feedwater components and ICS Major stations in hand (MFP stations)?

Answer 18

If above 55%, Adjust MFPs in approximately 5% increments followed by rod insertion.

When < 55% and MFW blocks open, stop power reduction, take SU and LL valves to hand (TS 3.7.3 applies), Open FW pump discharge X-tie, while Block valves are closing adjust in service MFP to maintain FW flows and reduce MFP to be tripped to minimum speed and trip when block valve closed.

Adjust LL/SU valves to lower FW flows while maintaining MFP discharge pressure 1050 - 1150 psig down to 30%.

When < 30%, Maintain SU level 30-40”. Insert control rods to lower power and adjust FW as needed.

If RX trips, maintain sg su levels 30-40”, TBV 980-1010 psig if in hand.

Question 19

What actions are required by exhibit 5 for MFP trip with main feedwater components and major ICS stations in hand (MFP stations and other major ICS stations).

Answer 19

1) Initiate continuous rod insertion
2) Raise demand for remaining MFP to max
3) Perform MFP trip actions per loss of SG feed
4) Place SU and LL valves in hand (TS 3.7.3 applies)
5) When within capacity of one pump and MFW Block valves closed, adjust SU/LL valves to lower FW flow and insert rods while maintaining MFP discharge pressure 1050 - 1150 psig.
6) Continue lowering FW and Rods to 40% power.