Zach Stubby's Heavy Hitters - Primary Systems Part 1 Flashcards
(160 cards)
1
Q
RCP Start Permissive
A
→ ≥600# Lift Oil pressure (Blue Light)
→Oil Lift Pump running to start RCP (Oil Lift pump manually S/D > 1 minute after RCP starts)
2
Q
What is the purpose of “Hot Loop/Cold Loop” control switch on RCP Breaker?
A
The “Hot Loop/Cold Loop” control switch used when starting RCPs
→”Cold Loop” position enables the “Locked Rotor” and “Failure to Accelerate” trips.
→”Hot Loop” blocks those trips to prevent a single point trip during normal plant operation in the event of a failed fuse
3
Q
RCP Trip Criteria (per ABN-101)
A
→ Seal Water Radial Bearing Temp ≥ 225°F
→ Motor Bearing Temp ≥ 195°F
→ Seal Water IN Temp ≥ 235°F
→ Motor Stator Winding Temp ≥ 300°F
→Loss of CCW Flow to Motor (Trip RCP w/in 1 minute)
→Loss of Seal Injection AND Thermal Barrier cooling
→Shaft vibration at 15 mils and increasing at > 1 mil/hr OR 20 mils
→Frame vibration at 3 mils and increasing at > 0.2 mils/hr OR 5 mils
4
Q
PRT Level band, pressure band, temp, rupture disc pressure?
A
→Filled 64-88% with reactor makeup water
→1-7 psig nitrogen atmosphere
→maintained <113°F
→Discharge into the PRT is through a sparger pipe beneath the water level
→Provided w/ 2 rupture discs @ 91 psid
→Normally cooled via RCDT HX
5
Q
Design temp of RCS
A
650°F, except for the PZR and its surge line, which is 680°F
6
Q
An RCP trip will also cause the associated SG to…
A
shrink and steam flow to drop off due to no heat transfer.
7
Q
Which RCP provides the best spray flow characteristics?
A
4 RCP. It is desirable to ensure it is kept available.
8
Q
How much seal leakoff flows up vs down the RCP shaft?
A
→ ~3 gpm flows UP the shaft, lubricating the radial bearing and leaking through the No. 1 seal
→ ~5 gpm flows DOWN the shaft, through the thermal barrier heat exchanger, and into the RCS
9
Q
Core Bypass Flow values
A
→ ~94% of the reactor coolant flow is available for heat removal; ~6% bypasses the core
The other 6%:
→2% - Control rod & instrument thimble bypass flow travels through the control rod guide and instrument thimble tubes of the fuel assemblies
→2% - Baffle cooling flow is the water that enters the baffle and former plate region just above the lower core plate and travels upward, removing heat, and exits the baffle and former plater region just below the upper core plate
→1% - Nozzle bypass flow travels directly from the inlet nozzles to the outlet nozzles.
→0.5% - Baffle wall bypass flow passes between the inside of the baffle wall and the fuel assemblies.
→0.5% - Head cooling bypass flow passes through holes drilled in the upper support structure flange & core barrel flange.
10
Q
Requirements to open #1 seal bypass valve
A
The No. 1 seal bypass valve should not be opened unless either the pump bearing temperature approaches 225°F or the No. 1 seal water inlet temperature approaches 235°F. These are also RCP trips.
The No. 1 seal bypass valve (u8142) should then be opened only if all of the following conditions are met:
→RCS pressure is between 100 psig and 1000 psig.
→No. 1 seal leakoff valve is opened.
→No. 1 seal leakoff flowrate is less than 1 gpm.
→Seal injection water flowrate to each RCP is at least 8 gpm.
11
Q
Mode 4 and 5 RCP start limitations
A
An RCP shall not be started in Mode 4 or 5 with any RCS cold leg temperature ≤350°F unless the secondary water temperature of each steam generator is <50°F above each of the RCS cold leg temperatures. (TS 3.4.6 and 3.4.7)
12
Q
What are some indications that natural circulation is occurring?
A
- RCS sub cooling - GREATER THAN 25°F (55°F FOR ADVERSE CONTAINMENT).
- SG pressures - STABLE OR DECREASING.
- RCS hot leg temperatures - STABLE OR DECREASING.
- Core exit TCs - STABLE OR DECREASING.
- RCS cold leg temperatures - AT SATURATION TEMPERATURE FOR SG PRESSURE.
13
Q
PRT Rupture Disc
A
The PRT is protected against a discharge exceeding the design value of 100 psig by:
→two rupture discs, set at 91 psid
→if containment press is 10 psig, then ruptures at 101 psig inside the PRT
→up until 91 psid, a stuck open PORV will drop RCS pressure at a decreasing rate; then, pressure drop rate will suddenly increase as the rupture disc fails
14
Q
Where do the PZR Spray Lines tap off from?
A
→two PZR spray valves modulate to control spray flow
→u-PCV-0455B provides spray flow from cold leg of loop 1
→u-PCV-0455C provides spray flow from cold leg of loop 4
→air-operated ball valves, fail closed on loss of air or power
15
Q
The Subcooled Margin Monitor (SMM) compares…
A
…wide range RCS pressure indication with the highest CET temperature and RCS hot and cold leg temperatures.
16
Q
At what temperature/flow do the RCP Thermal Barrier return lines isolate?
A
→Thermal Barrier return lines isolate on:
→high temperature 182.5°F on each pump (IRC) and uHV-4709 (ORC)
→high flow 64 gpm on uHV-4696 (IRC).
(The arrangement on the flow diagram is “TFT”)
(TFT = temperature, flow, temperature)
17
Q
Charging Flow - Letdown Flow - Total Seal Leakoff Flow = ?
A
0 gpm
can be used to determine quantity of RCS leaks as well as charging, letdown, or seal leakoff if given the other values.
Total Seal Leakoff might also be called seal return. Could be given per pump or the total of the four pumps together.
18
Q
Normal RCS Parameters:
RCS Volume
A
Unit 1: 95,000 gal
Unit 2: 91,000 gal
19
Q
Normal RCS Parameters:
RCS Flowrate
A
Unit 1: 403,700 gpm
Unit 2: 408,000 gpm
20
Q
Normal RCS Parameters:
T-cold
A
Unit 1: 560
Unit 2: 559
21
Q
Normal RCS Parameters:
T-avg
A
Unit 1: 557-585.4
Unit 2: 557-589.2
22
Q
Normal RCS Parameters:
PZR Level
A
25% - 60%
23
Q
What are the must-know RCS connections?
A
→Letdown - Loop 3 Intermediate Leg
→Excess Letdown - Loop 1 Intermediate Leg
→PZR Spray - Loops 1 & 4 Cold Legs
→PZR Surge Line - Loop 4 Hot Leg
→Charging - Loops 1 & 4 Cold Legs
→RHR - All 4 Cold Legs, Loops 2 & 3 Hot Legs
→SI - All 4 Cold Legs, All 4 Hot Legs
→CCP High Head Injection - All 4 Cold Legs
24
Q
Rx Vessel O-ring leakage is routed to the…
A
RCDT (identified leakage)
25
At what temperature does leakage from the Rx Vessel O-rings alarm in the Control Room?
alarms at 140°F
(uTE-0401 with indication on MCB)
26
What do the secondary core supports do?
Limits the distance the core barrel will drop in a postulated failure of the core barrel flange and is designed to absorb the energy of the drop and limit the fall to ensure that the control rods may be inserted, coolant flow will not be blocked, and all fuel assemblies will remain within the core baffles.
27
Head Vent Valves
→Where are they powered from?
→How do they fail?
→Where do they vent to?
Two key operated valves
→powered from uED1-1
→fail closed on loss of power
→vent to containment atmosphere
(piped in series → if one fails, there is still isolation from the vessel)
28
How many fuel assemblies in the Rx Vessel?
How many control rods?
→193 fuel assemblies
→53 control rods
29
What are the different parts and percentages of Core Bypass Flow?
→2% control rod and instrument thimble bypass flow
(flows through CR and instrument thimble tubes in fuel assemblies without removing any heat generated by core)
→2% baffle cooling flow
(enters baffle and former plate region above lower core plate, exits baffle and former plate region below upper core plate)
→1% nozzle bypass flow
(directly from inlet nozzles to outlet nozzles)
→0.5% baffle wall bypass flow
(passes between inside of baffle wall surrounding fuel assemblies and the fuel assemblies themselves without rmeoving any heat generated by core)
→0.5% head cooling bypass flow
(passes through holes drilled in upper support structure flange and core barrel flange to maintain reactor head area at cold leg temp)
(percentages are approximate)
30
RVLIS TS light requirements
TS requires 4 lights per train with min of 1 in the head and 3 in the core to be operable
31
RVLIS Light Setpoints
→if thermocouple ΔT >200°F, then light goes out
→if thermocouple ΔT <100°F, then light is on
32
How does the CCM Subcooled Margin Monitor (SMM) calculate Saturation Margin?
→Using the auctioneered hi temperature and auctioneered low pressure it calculates Saturation Margin
→(u-TI-3611-1) uses auctioneered Hi Temperature (Failed TCs are removed from scan)
→range: 300° F above to 300° F below saturation temp
33
Subcooled Margin Monitor Inputs (4)
1. Highest CET
2. RCS Loop RTD temperatures
3. RCS Loop pressures
4. PZR pressure
34
What are the power supplies for CCM & RVLIS?
→Train A/B CCM powered from uEC5/uEC6
→Train A/B RVLIS powered from uEC5/uEC6
35
PS-5385/5385A (upstream of PCV-131) provides local pressure indication and HELB alarm at...
≤ 200 psig
36
Closure of 8152 or 8160 (CIV downstream of orifice valves) will cause relief valve 8117 to lift and discharge to the PRT, resulting in a....
LOCA. Operator action required to isolate LTDN at this point.
37
Purpose of the mixed bed demins
(2 mixed beds, one in use at a time)
Use lithiated resin to remove corrosion products by filtration and ionic impurities (chemical contaminants and fission products) from the RCS
38
VCT Backpressures
→H2 pressure maintained around 25 psig
→ >15 psig for Seal #1 backpressure for adequate flow to #2 Seal
→10 psig when degassing to prevent reverse pressurization on #2 RCP seal
39
The CCP alternate miniflow relief valves recirc to where?
RWST
(lift at 2200 psig)
40
What PDP speed is required to maintain adequate oil pressure?
55 gpm. Otherwise the PDP is likely to trip on low oil pressure (4 psig) 90 seconds after breaker closure.
41
How does PDP speed fail on loss of air?
to its maximum speed
(98 gpm)
42
What is required to start the PDP?
→8109 must be open (PDP recirc valve)
→No train A BO (OL)
→No train A SI (AL)
→HS taken to START
Note: If HS is taken to START with 8109 closed, it will auto-open. Once 8109 is open, PDP HS will need to be taken back to START to start the pump.
43
PDP Trips
→Train A SI (breaker is load shed/shunt tripped)
→Low Lube Oil Pressure (4 psig, >90 sec after pump start)
→Undervoltage
→Overcurrent
44
What is the power supply for LCV-459/460?
How do they operate?
→uED1-1
→AOVs fail closed on loss of air or power
→power supplied from Train A only
45
How do 8149A/B/C Orifice Isolation Valves operate?
46
HCV-128 RHR to Letdown Line power supply and use
→Hagan controller powered from uPC1
→AOV, fails closed
→Used when RHR is aligned to letdown for Modes 4-6
→Used full open; flow is controlled via PCV-131.
→can come from either train RHR
47
TCV-129 CVCS Demin Bypass purpose and setpoints
→powered from uED1-1
→diverts to VCT; bypasses CVCS demins at 135° F (input from TIS-129) and BTRS at 155° F (TIS-382)
→three position handswitch: Demin, Normal, VCT
→if it diverts to VCT on high temp, when the temp comes back down, it will remain in VCT; must take handswitch back to Demin to change valve position back to demin
48
LCV-112B/C VCT Outlet Auto Close
→VCT Lo-Lo of 2% on BOTH LT-112 and LT-185
→SI
(also switches charging suction source to RWST on VCT Lo-Lo of 2%)
49
FCV-121 Alarms
→Lo Flow Alarm ≤ 55 gpm
→Hi Flow Alarm ≥ 150 gpm
→Mini flow in auto is 55 gpm
→fail open AOV fed from FT-121
→charging flow indication limited to 270 gpm due to FT-121
(Normally measures charging flow + RCP #1 seal leakoff. After SI, it will measure RCP Seal Injection flow.)
50
VCT Level Control (Level Channel 112) makeup start and stop setpoint
→Makeup starts 46%
→Stops at 56%
(10% level ≈ 200 gal)
51
What occurs when you raise/lower Letdown HX outlet temperature?
→Raise T: negative reactivity due to releasing boron
→Lower T: positive reactivity due to absorbing boron in mixed beds
→Per SOP-103, when placing a standby bed in service, special care should be taken not to add positive reactivity due to absorption of boron in the bed
52
What is the power supply for the PDP?
uEB1
53
What happens if TCV-4646 (Letdown HX CCW outlet valve) fails?
→fails open
→will cool letdown and might cause dilution event
54
What is the normal flow through the Seal Water Heat Exchanger?
72 gpm
(60 gpm CCW miniflow plus 12 gpm RCP seal return)
55
What are the CCP auto-starts?
→train associated SIS start signal
→train associated BOS start signal
56
What are the CCP automatic trips?
→safeguards bus undervoltage
→86M motor lockout
57
CCP Alternate Miniflow Basic Facts
1 set for each CCP
CCP u-01:
→8511A upstream valve - train A uEB1-1 - normally closed
→8512B downstream valve - train B uEB4-1 - normally open
→Discharge through 8510A relief to RWST - 2200 psig at 84 gpm
CCP u-02:
→8511B upstream valve - train B uEB4-1 - normally closed
→8512A downstream valve - train A uEB1-1 - normally open
→Discharge through 8510B relief to RWST - 2200 psig at 84 gpm
58
Letdown Relief Valve 8117 Basic Facts
→relieves at what pressure?
→design flow
→relieves to
→600 psig
→195 gpm
→PRT
59
What is the purpose of u-PCV-0131 (Letdown HX outlet pressure control valve)?
→maintains backpressure on letdown line between orifices and letdown HX until temp is low enough to prevent flashing in the HX
→controls RCS pressure during solid plant ops
→310 psig in, 35 psig out
→high pressure alarm at 499 psig
(AOV, fails open)
60
When does the VCT low level alarm come in?
16%
61
When does the VCT high level alarm come in?
70%
62
When does letdown start automatically diverting some flow to the RHUT?
62% level in VCT
63
When is letdown flow being fully diverted to the RHUT?
98% level in VCT
(also high-high level alarm)
64
HCV-182 & FCV-121 Failures
→both fail open AOVs
→if 121 fails open, max water to charging, max to seals
→if 182 fails open, max water to charging, minimum water to seals
65
What powers u-8104 (Emergency Borate Valve)?
→uEB4-1
→Controlled by either MCB or RSP
→no automatic functions
66
What happens to RMUW on SI?
→VCT outlet valves close after RWST to CCP valves open
→RMUW Pumps stop until SIS or BOS OL clears, restart after ~130 seconds
→Normal heat trace panels load shed
67
Does FCV-110A fail open or closed?
Fail Open AOV (continue to manual emergency borate)
68
How does AUTO makeup work?
→makeup starts at 46% VCT level
→makeup stops at 56% VCT level
→total max flow 127 gpm (max in auto)
→aligned to VCT outlet
69
Boric Acid Transfer Pump power supplies and flow
→X-01: uEB1-1
→X-02: uEB4-1
→75 gpm @ 100 psig
→can be controlled at RSP; no auto position on RSP
70
How are FK-111 and FK-110 maintained? Auto vs. manual.
→FK-111 and FK-110 maintained in manual
→swap to auto when an auto makeup occurs
→if manual pushbutton is pushed, it will seal in and prevent swap to auto
→to remove the seal-in, push the auto pushbutton
71
Pot settings and max flow for FK-110
→FK-110 is 10 turn pot to control flow 0-40 gpm
→controls flow from BATs
→27 gpm considered maximum flow
→pot setting is desired flow/4
72
BA Flow Deviation Alarm
Desired flow is not obtained within ±1 gpm within 25 seconds. If occurs, it closes FCV-110B and FCV-111B.
73
BAT and RWST min level (MODES 1-4)
→BAT must be >50%
→RWST must be >95%
→per TR 13.1.31
74
RMUW Flo Deviation Alarm
Desired flow is not obtained within ± 8 gpm within 25 seconds. If occurs closes FCV-110B and FCV-111B.
(FCV-111B should already be closed in this case since any flow with boron is directed to the bottom of the VCT.)
75
Pot settings and max flow for 111
→FK-111 is 10 turn pot to control flow 0-160 gpm
→controls makeup flow through blender (RMUW + BA)
→127 gpm hard setpoint for AUTO overrides pot setting
→pot setting is desired flow/16
76
How do you calculate boric acid flow for blended flow?
BA Flow x BAT conc = TOTAL Flow x RCS conc
77
If TIS-382 fails high...
TCV-129 diverts to the VCT and bypasses the letdown demins.
78
Per SOP-106 the max allowable flow(s) through BTRS demins...
is 164 gpm for one, and 300 gpm for two.
79
What is the setpoint for TE-382? What occurs at this setpoint?
TE-382 alarms @ 155°F and diverts TCV-129 to bypass the demins.
80
What is the fail position for BTRS?
Fails in a boration lineup, i.e. valves 7056, 7057, 7045, and 7046 fail to place demins in boration lineup
81
Pressurizer Pressure and Level Control systems are designed to accommodate what transients without a reactor trip?
→Loading or unloading at a rate of 5% per minute with automatic rod control
→Instantaneous load changes of 10% with automatic rod control
→Step-load reductions of 50% with automatic rod control and steam dumps
82
What is the 0% power Program PZR Level and T-ave?
What is the 100% power Program PZR Level and T-ave?
0%
→25% level,
→557°F no load T-ave
100%
→60% level
→585.4°F (589.2°F)
(Level controlled by average T-ave, not power)
83
PZR Handswitch PS-455F top channel feeds what?
PZR Handswitch PS-455F bottom channel feeds what?
→Top: PORV PCV-455A
→Bottom: PORV PCV-456
84
PZR Pressure Hi Alarm setpoint
2310 psig
(also spray full open)
85
PK-455A feeds what?
→PCV-455A
→Pressurizer pressure Deviation High alarm
→Pressurizer pressure low, backup heaters on
→Backup heater control
→Variable heater control
→PK-455B (loop 1 spray)
→PK-455C (loop 4 spray)
86
At what pressure do PORVs open?
At what pressure do PORVs close?
Open: 2335 psig
Close: 2315 psig
(blocked from opening below 2185 psig)
87
If a conflict occurs between Level Control and Pressure Control which takes priority?
Level control is dominant
88
PORV rated flow
210,000 lbm/hr
89
When do pressurizer heaters energize?
→Decreasing pressure (PK-455A output at ~42%)
→Pressurizer Level 5% above program
90
How is LT-462 calibrated, and when should it be used?
→Cold calibrated: Low temperature conditions (70°F).
→Whenever RCS temperature is < 450°F.
→Note: cold cal always indicates lower than hot cal.
91
What does LK-459 provide control for?
→PDP speed
→FCV-121 position
92
What is the PZR lower program level limit and what is it designed to prevent?
→Lower program level limit of 25%
→Prevents emptying PZR on Rx trip and from uncovering heaters on normal transient.
93
What is the PZR upper program level limit and what is it designed to prevent?
→Upper program level limit of 60%
→Leave enough room for surges
→Prevents Rx trip on high level for transient
→Prevents water going out the safeties on a load reduction of 100%
94
What occurs if a PZR bottom level control channel fails low, with no operator action?
→LCV-460 Closes
→Orifice isolation valves close
→All heaters de-energize
→PDP Speed decreases or FCV-121 throttles closed as actual level increases
→Actual level will increase (very very slowly) until Rx Trip occurs on hi level.
95
What occurs if a PZR top level control channel fails high, with no operator action?
→All heaters energize (insurge of > 5% above program)
→PDP Speed goes to min or -FCV-121 throttles closed
→Actual level decreases until 17% is reached which causes letdown to isolate and heaters to de-energize
→Actual level will increase (very very slowly) until Rx Trip occurs on hi level.
96
What occurs if a PZR top level control channel fails low, with no operator action?
→LCV-459 Closes
→Orifice isolation valves close
→All heaters de-energize
→PDP Speed goes to Max or FCV-121 goes full open
→Actual level increase until Rx Trip occurs
97
What occurs at 17% PZR level with a decreasing level?
→17% on the Primary Control Channel causes LCV-459 to close (letdown isolation)
→17% on the Secondary Control -Channel causes LCV-460 to close (letdown isolation)
→Orifice isolation valves close (either control channel)
→PZR Heaters de-energize (either channel)
→Low Level Alarm
98
High Failure of PZR top pressure Channel 455 or 457
→Spray Valves go FULL OPEN
→Heaters go to FULL OFF
→PORV PCV-455A sees an actuation signal and lifts since actual plant pressure, as sensed by channel 458, is above the interlock setpoint of 2185 psig.
→Plant pressure lowers rapidly
→At 2185 psig, the interlock signal from channel 458 is removed to allow PCV-455A to close.
→Pressure continues to lower due to the open spray valves.
→An OT N-16 turbine runback occurs (could also provide Rx trip)
→The reactor trips on lead-lag compensated low pressure because channels 456, 457, and 458 are still available to provide the necessary 2 of 4 logic at 1880 psig for the reactor trip.
→Plant pressure continues to drop after the plant trip. At 1820 psig an SI occurs.
99
PORV and Block Valve Power Supplies
→PORVs: train related 125 VDC
→Block Valve u8000A: uEB3-2
→Block valve u8000B: uEB4-2
100
Arming Interlocks
Interlock signals from PT-457 (for PCV-456) and PT-458 (for PCV-455A) are used to allow PORVs to open on hi pressure however if pressure drops below setpoint of 2185 psig then the signal is removed and the PORV is blocked from opening (or PORV is closed if open)
101
PORV Accumulator sizing
→sized for cycling 100 times in 10 mins
→located CTMT 905'
→alarm provided on MCB for <90 psig in Accumulator
102
Heater Control Group after trip
Control Group C H/S must be taken to ON to reclose supply breaker after trip
103
Backup Heaters After Trip
After trip, backup heater breakers will energize if demanded UNLESS they were ON before trip then they will need to be reset by taking H/S to OFF then to AUTO
104
PZR Heater Power Supplies
→A: uEB3
→B: uEB2
→C: uEB1
→D: uEB4
"CBAD" for uEB1, 2, 3, then 4
105
PZR Heatup and Cooldown Limits
→100° F per hour heatup
→200° F per hour cooldown
(minimizes fatigue stress in accordance with ASME requirements)
106
What is the thumb rule for finding what the programmed level for the pressurizer should be?
U1: (Actual T-avg - 557) x 1.23 + 25%
U2: (Actual T-avg - 557) x 1.09 + 25%
107
What is the thumb rule for determining demand on the master pressure controller?
→Demand signal is 50% at 2235 psig.
→Every pound of pressure above or below 2235 changes demand by 0.31%.
108
What level does the Hi PZR Level Alarm come in?
70%
109
What level does the Hi PZR Level Rx Trip come in?
92%
110
What does the top PZR level control channel control?
→LK-459 (PDP speed and FCV-121)
→heaters on - high level deviation
→closes LCV-459 (17%)
→heaters off (17%)
→orifice valves closed (17%)
→low level deviation alarm
→low level alarm
111
What does the bottom PZR level control channel control?
→high level alarm
→low level alarm
→closes LCV-460 (17%)
→heaters off (17%)
→orifice valves closed (17%)
112
Where does P-11 (PZR SI Block Permissive) input come from?
→PC1, 2, and 3 (NOT PC4)
→coincidence is 2/3
113
What is the RCS pressure safety limit?
2735 psig
114
When do the PZR safeties lift?
2460 psig
115
When does the reactor trip on PZR high pressure (or RCS overpressure)?
2385 psig
(2/4 channels)
116
When do the PORVs open?
When do they close?
open: 2335 psig
close: 2315
Note: setpoint for PORV 455A is based on controller output (top channel), so there could be some variation in what the actual pressure is when it begins to open. PORV 456 has a hard setpoint (bottom channel). It will open at 2335 psig.
117
When does PZR spray start to open?
When is PZR spray full open?
starts: 2260 psig
full open: 2310 psig
(spray driven by top channel)
118
When are PZR control/variable/proportional heaters on at minimum current?
When are PZR control/variable/proportional heaters at maximum current?
min: 2250 psig
max: 2220 psig
119
When do PZR backup heaters turn on?
When do PZR backup heaters turn off?
on: 2210 psig
off: 2218 psig
120
At what pressure are PORVs blocked?
2185 psig
→channel 457 feeds PCV-455A
→channel 458 feeds PCV-456
121
When does P-11 happen?
1960 psig
→PZR SI block permissive
→2/3 channels
→channels 455, 456, 457
122
When does the reactor trip on PZR low pressure?
1880 psig
(2/4 channels)
123
When does SI actuate on PZR low pressure?
1820 psig
(2/4 channels)
124
Which channel is PZR spray driven by?
the top channel
125
Why do we add Argon to the VCT?
→in VCT for primary to secondary leak detection
→improves detection in Condenser Off Gas Radiation Monitor
126
STA-609 Fluoride and Chloride Action Levels
Action Level 1: >50ppb
Action Level 2: >150ppb
Action Level 3: >1500ppb
(each, not total)
127
STA-609 Dissolved Oxygen Action Levels
Action Level 1: >5ppb
Action Level 2: >100ppb
Action Level 3: >1000ppb
128
When do we add chemicals to the RCS?
What is the exception to that?
→through CVCS when RCPs are running
→exception: SOP-101 - adding hydrazine into PZR before drawing a bubble
129
What are the TRM limits for dissolved oxygen below 250° F?
→prior to heatup above 180° F, O2 should be <2,000 ppb (2 ppm)
→prior to heatup above 250° F, O2 SHALL be ≤100 ppb (0.1 ppm)
130
Tech Spec 3.4.16 RCS Specific Activity
RCS Dose Equivalent I-131 and Dose Equivalent Xe-133 specific activity shall be within limits (Modes 1-4)
→Dose Equivalent I-131 spec is ≤ 0.45 μCi/g
→Dose Equivalent Xe-133 spec is ≤ 500 μCi/g
131
Max Containment Pressure and Temp
→max design pressure: 50 psig
→max design temp: 280°F
(applies to the structure, not the inside atmosphere)
132
CNTMT PRESS HI 1 alarm
→3.2 psig (1/3)
→2/3 channels provides SI (Channels 2-4)
133
CNTMT PRESS HI 2 alarm
→6.2 psig (1/3)
→2/3 generates MSL Isolation (Channels 2-4)
134
CNTMT PRESS HI 3 alarm
→18.2 psig (1/4)
→2/4 generates Containment Spray Actuation (Channels 1-4)
→requires relays to energize to actuate; loss of power will not cause CS actuation
135
Containment Pressure IR Channels
Channel 1 - 937
Channel 2 - 936
Channel 3 - 935
Channel 4 - 934
136
TS 3.6.4 CTNMT Pressure
→ctnmt pressure must be maintained ≥-0.3 psig and ≤1.3 psig
→use pressure relief system to maintain
137
TS 3.6.5 CTNMT Temperature
→ctnmt average temp must be ≤120°F
→start additional CACRS to maintain
138
Which accidents is containment designed to protect against?
→large break LOCA (i.e. double ended pipe shear)
→faulted S/G (a.k.a. major steam pipe rupture)
139
Temperature at which PORVs automatically arm for LTOP
≤350° F
(automatically disarm >350° F)
140
TS 3.4.12 requirements for LTOP
→2 RHR suction reliefs (lift @ 450 psig ± 3%), or
→2 PORVs, or
→1 of each
→0 SI pumps capable of injecting
→2 charging pumps capable of injecting
→0 accumulators capable of injecting
If these requirements are not met, then the RCS must be depressurized and a 2.98 sq in vent path must be made in the RCS pressure boundary.
141
Describe the LTOP circuitry by train
Each train consists of 4 inputs feeding 2 auctioneered low circuits with 1 train providing input into a setpoint generator and the other supplying the permissive to open the opposite train's PORV.
142
Train A LTOP Inputs
For PCV-455A:
→T-hot 413A (Loop 1)
→T-hot 423A (Loop 2)
→T-cold 433B (Loop 3)
→T-cold 443B (Loop 4)
→PT-405 (Loop 1 WR pressure)
Temperature arms Train B, but pressure operates Train A
143
Train B LTOP Inputs
For PCV-456:
→Tcold 413B (Loop 1)
→Tcold 423B (Loop 2)
→T-hot 433A (Loop 3)
→T-hot 443A (Loop 4)
→PT-403 (Loop 4 WR pressure)
Temperature arms Train A, but pressure operates Train B
144
LTOP is required when any CL temperature is...
(TS 3.4.12)
≤ 320°F
145
When LTOP is required by TS 3.4.12, the following is also required to ensure no heat transients beyond LTOP capability occur:
1. render all SIPs and one charging pump incapable of injection
2. close and deactivate SI accumulator discharge valves
3. preclude the start of RCPs if secondary water temperature is > 50°F above primary
146
Per TS 3.4.12, LTOP applies Mode 4, 5, and 6 (when RV head on), but does not apply when all RCS CL temperatures > 320°F and all of the following are met:
1. at least 1 RCP operating
2. PZR level ≤ 92%
3. Plant heatup rate is limited to 60°F per hour
Note: LTOP will still arm ≤350°F
147
What are the LTOP PORV setpoints for different temperatures?
148
Cold Leg Power Shadowing
Nuclear Engineering has estimated that the effect on PR NIS is approximately 0.8 % per degree at 100% power.
The effect is decreased proportionally with power. For example at 50% power, the effect is halved or 0.4% per degree.
149
Auctioneered Low T-ave is used to...
→generate C-16 at 553°F
OR
→generate C-16 when auctioneer low T-ave is < T-ref by 20°F
150
Ave T-ave provides input to...
1. Pressurizer Level - used to develop program level
2. Steam Dump Control
3. T-ave Deviation Alarm
4. Rod Control
5. Reactivity Computer
6. Rod Insertion Limit (wires hooked up but system set such that it has no effect)
7. High T-avg alarm 587.2°F (591°F)
8. Tavg - Tref Deviation Alarm ± 2.5°F
151
What signals does T-ave input to?
1. FW Isolation Signal (T-ave = 564°F AND P-4) requires 2 of 4 channels (Lo T-ave)
2. P-12 Lo-Lo T-ave permissive at 553°F causes Steam Dumps to isolate, requires 2 of 4 channels (can be bypassed for cooldown for 3 of 12 dumps)
152
Inputs to OT N-16 Setpoint Circuitry
1. PZR Pressure
2. PR Detectors (looks at ΔI for associated channel)
3. T-cold narrow range
(setpoint is 115% ± penalties)
153
N16/Tcold Fails Low
→affected T-ave channel fails low (510°F)
→may cause a "Stop Turbine Loading" (C-16) to be actuated. (low auctioneered T-ave less than 553°F or Tref-Tave mismatch greater than 20°F).
→channel failure low will cause rods to withdraw if rod control is in AUTO, stops at C11
→PZR reference level decrease with charging flow decrease when in auto
154
N16/T-cold Fails High
→affected T-ave channel fails high (630°F)
→rapid control rod insertion due to Tave-Tref mismatch if in AUTO.
→steam dumps will open if armed with a C-7 (loss of load).
→PZR reference level increase (to a maximum of 60%) with charging flow increase when in auto
155
How does an RTD fail on an open circuit?
How does it fail on a short circuit?
→open circuit = fails high, infinite resistance
→short circuit = fails low, zero resistance
156
RCDT Pump Trips
→Low level: 20%, manual restart
→Low flow: <50 gpm, manual restart
→must be manually restarted following blackout
→must be manually restarted after SI (buses are load shed, MCC must be energized again)
powered from:
→pump #1: uEB1-2
→pump #2: uEB2-2
157
RCDT HX Design
→HX designed to maintain RCDT <170°F (10 gpm @ 600°F and 25 gpm from excess letdown)
→Normal: cool PRT from 200°F to 120°F in 8 hours using CCW
→Abnormal - cool PRT using Rx Makeup fill/drain in 1 hour
158
LCV-1003 Design Reqs
→closes on phase A
→used to automatically maintain tank @ 39% by transfer to RHUT
→if both pumps running, RCDT HX must be bypassed and u-7135 must be opened to prevent exceeding design flow of HX (120 gpm) and LCV-1003 (80 gpm)
→discharges to RHT (Normal), SFP (Makeup Source) or WHT
159
Where can RCDT flow go?
→RHUT
→SFP
→WHT
→PRT
160
Where can RCDT flow come from?
→vessel head O-ring leakoff
→Excess Letdown
→#2 RCP seal
→RCS Loops (need spoolpiece)
→SI Accumulators (need spoolpiece)
→PRT (for cooling)
→Refueling Canal
