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
What affect does the rupture of “a” bellows on a PZR level detector have?
None, each detector has two bellows
Which pressure transmitters feed P-11?
PT-455, 456, 457
RCS pressure control (increasing)
2460# Safeties lift 2385 Reactor trip 2345 RY-455 lifts 2335 RY-456A lifts 2310 Spray valves full open 2260 Spray valves start to open 2250 Variable heaters full off 2235 NOP 2225 BU heaters full off 2220 BU heaters full on 1930 SI block permissive P-11 clears
RCS pressure control decreasing
2315 PORVS closed 2310 Spray valves start to close 2260 Spray valves full closed 2250 Variable heaters start increasing 2235 NOP 2220 BU and variable heaters full on 2185 PORVS blocked 1930 SI block permissive P-11 clears 1885 Rx trip- rate sensitive 1829 Safety injection
What is the effect on PZR level when each of the following occurs? Cont temp increases Ref leg leaks DP diaphragm ruptures Variable leg loss
Up; Up; Up; Down
CV-121 is clipped on the low end at _____ to maintain _____.
52 GPM; 13 gpm seal injection flow for each RCP
PZR pressure alternate actions occur if:
4 ch bad
4 ch exceed 80# deviation
2 ch bad and 2 good exceed deviation
1ch bad and 3 good exceed deviation
Alternate action locks in lagged input and forces master pzr press controller to manual
PZR level control alternate actions occur if:
3 channels bad quality
3 channels exceed dev band 10%
1 channel bad quality and
1other channel exceeds dev band
If an alternate action occurs on pzr level, then master pzr level controller is switched to manual, letdown isolation logic is blocked for the drop in the alt. action.
Charging flow alternate action occurs if:
Single charging flow input is bad quality. PZR level will control based on level error only.
What is the flow rate of the spray valves and bypasses?
450 gpm and 1 gpm
If RCPs are unavailable, can pzr spray be used?
Aux spray
Which heater groups can be controlled from outside the control room?
A and B BU heaters from remote shutdown panel.
what is the pressure which results in a pressurizer pressure high deviation control alarm?
2310#
At what PRT pressure will the gas analyzer line be auto isolated?
6#
What are the three items that must be met to meet the TS for the pressurizer?
Level <= 92%
2 groups with 150 KW each
ESF to non-ESF cross tie available (must be able to power from EDG)
PAM required channels
2 NR pzr level
TRM pressurizer temp limitations
100F/Hr heatup rate
200F/hr cooldown rate
<=320F spray to pressurizer DT limit
SI termination criteria, in general
pressurizer level, inventory
Pressure, stable or increasing
Subcooling, including a secondary heat sink
Adverse containment
5psig, or 1E5 R/Hr
