Pressurizer system Flashcards
PZR program level and program Tave for each unit:
Unit 1 25-60% 557-586.5F
Unit 2 27-60% 557-581F
What is/are the purpose(s) of the pressurizer?
A: Maintain RCS press, accommodate transients, FP barrier
Why is water level in the PZR programmed to vary with RCS average temperature?
A: Minimize the mass xfer in and out of the RCS. This minimizes impact on CV when changing power
What is the design flow and setpoint of the PZR safeties based on?
A: Complete loss of load, with S/G safeties and FW flow, with: No Rx Trip, auto rod movement, No RY PORVS, No Steam dumps or MS PORVS, No RY level control actions or RY Sprays
What is the setpoint of the PZR safeties?
2460 psig
PZR contains about _____gallons per % level
120
Safety function of PORVs
LTOP
List PZR operational design criteria:
A: 5%/min w/o Rx Trip and Rods in Auto, 10% step change w/o Rx Trip or uncovering heaters, 50% step load reduction w/ rods in auto and steam dumps. Complete loss of load with Rx trip due to Hi PZR level and no water out safeties
PZR backup heaters auto energize when _____% above program level. This _________.
> =5%; Heats cold water from an insurge to saturation
PZR heater group setpoints, KW rating, and power supplies
A 21 on 2220 1400 KW 143 B 21 off 2225 144 C 18 full on 2220 400 KW 144 full off 2250 D 18 143
At PZR level of_____pzr heaters auto shutoff. Backup are _____reset. Variable are _______reset.
<17%. Backup heaters auto reset, variable must be reset manually.
PZR spray valves start to open at ______. Full open at ______.
2260psig; 2310 psig
Bypass flow to:
Max temp difference for spray:
Keep spray and surge lines warm
Mix Pzr and RCS
Prevent thermal shocking spray nozzle
Spray/Pzr vapor Delta T limit of 320°F
RY 455A opens at ______
RY 456 opens at________
Both reset at ______
2345#
2335#
2315#
PORV interlock setpoint_______
2185#
PRT rupture disc breaks at _____ psid
100 psid
RCDT level tree
60% RE 1003 opens, A pump starts
80% B pump starts
38% RE 1003 closes, B pump stops
What systems go into the PRT?
i. Miscellaneous Leak Offs
1) Valve Leak Offs (Hot & Cold Leg Isolation, RHR. Suction, L/D, etc.)
2) RCP Seal Water Relief Valve
3) Letdown Orifice Relief Valve
PZR (porv, safety)
Nitrogen
PW
3.4.10 PZR safety valves
3.4 REACTOR COOLANT SYSTEM (RCS)
3.4.10 Pressurizer Safety Valves
LCO 3.4.10 Three pressurizer safety valves shall be OPERABLE with lift
settings 2411 psig and 2509 psig.
—————————-NOTE—————————-
The lift settings are not required to be within the
LCO limits during MODE 3 for the purpose of setting the
pressurizer safety valves under ambient (hot) conditions.
This exception is allowed for 54 hours following entry into
MODE 3 provided a preliminary cold setting was made prior to
heatup.
————————————————————
APPLICABILITY: MODES 1, 2, and 3.
15 minutes to restore if one inop
Inop PORV actions.
IF PORV still capable of being cycled, block valve must be _____ and _______.
IF PORV can not be controlled manually, block valves must be ______and _______.
Closed; can remain energized
Closed; de energized
3.4.10 PZR TS
3.4 REACTOR COOLANT SYSTEM (RCS)
3.4.9 Pressurizer
LCO 3.4.9 The pressurizer shall be OPERABLE with:
a. Pressurizer water level <= 92%; and
b. Two groups of pressurizer heaters OPERABLE with the
capacity of each group >=150 kW and capable of being
powered from redundant Engineered Safety Features (ESF)
power supplied buses.
APPLICABILITY: MODES 1, 2, and 3.
3.4.12 LTOP
Mode 4, 5 and 6 (if vessel head on)
Max of 1 charging pump, no SI pumps capable of injecting.
Each accumulator isolated if >Max allowed RCS pressure
One of following relief capabilities:
-Two PORVs set per PTLR
-Two RHR suction reliefs <=450psig
-One PORV and one RHR suction relief
-or-RCS depressurized with RCS vent >=2.0 inch diameter
—————————-NOTES—————————
1. Operation in MODE 4 with all SI pumps and charging
pumps capable of injecting into the RCS is allowed when
all RCS cold legs exceed 330F.
2. For the purpose of protecting the decay heat removal
function, one or more SI pumps may be capable of
injecting into the RCS in MODE 5 and MODE 6 when the
reactor vessel head is on provided pressurizer level is
≤ 5 percent.
—————————-
PZR level setpoints:
Trip above P-7 92%
Hi level alarm 70%
Low level alarm 17%
17% closes orifice isol valves, LD isolation valves close, PZR heaters off
+5% deviation, BU heaters full on and alarm
-5% deviation, alarm
LTOP RC temp below arm setpoint _____
RC system cold pressure high_________
RC pressure high at low temp, PORV open______
360F
RC WR pressure w/i 20# of function generator lift stpt
RC WR pressure > func gen and C/S in arm
