Systems Exam 2 Comprehensive Deck for Review Flashcards
(321 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 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
What cools the RCPs?
A
→RCPs are cooled by CCW
→the motor portion and thermal barrier portions have separate return lines and a common supply line
9
Q
For the #1 seal, what is the temperature limitation?
A
Seal injection temperature should be kept less than 130°F to the #1 seal.
10
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
11
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.
12
Q
Normal RCS Parameters:
A
→Volume: 95,000 (91,000) gal
→Flow Rate 403,700 (408,000) gpm
→Pressure 2235 psig
→T-hot 618°F (620°F)
→T-cold 560°F (559°F)
→T-avg 557-585.4 (589.2)
→PZR Level 25%-60%
13
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.
14
Q
Pressurizer PORVs N2 Accumulators rating
A
→2 PORVs controlled by PZR Pressure Control System
→210,000 lbm/hr each
→use N2 for motive force
→supplied w/ N2 accumulators to allow associated valve to be stroked 100 times in 10 min
15
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)
16
Q
RCP Motor Start Limitations
A
Per SOP-108:
1. Two successive starts are permitted, provided the motor is allowed to coast to a stop between starts (5 minutes).
2. A third start may be made when the winding and the core have cooled by running a period of 20 minutes, or by standing idle for a period of 45 minutes.
3.Only one RCP is to be started at any one time
17
Q
RCP Start Motor Oil Lift Interlock
A
There is a permissive interlock in the RCP motor start circuit that does not allow the RCP to be started until:
→oil lift pressure has reached 600 psig (Blue Light)
→oil pump running; admin time of 2 minutes running prior to start.
18
Q
Are there any auto starts for the Oil Lift Pumps?
A
→there are no auto start features for oil lift pumps
→if the RCP trips or is stopped, the thrust bearing will maintain its oil wedge on coast down
19
Q
PZR Safeties:
→lift setpoint
→rated flow
→design function
A
→3 Safeties, 420,000 lbm/hr each
→lift setpoint 2460 psig with a 3% accumulation
→Designed for the maximum surge rate resulting from a complete loss of steam flow to the main turbine without a Rx Trip, auto rod control, steam dumps, PORVs or operator action
→Temp indication provided downstream of PORVs (common for both) and downstream of each safety, alarms provided at 160°F.
→Position indication uses magnetic reed switches to indicate either fully open or fully closed.
20
Q
RCP Trip Criteria (ABN-101) for seals
A
→#1 Seal Leakoff problems (see chart)
→Total #1 Seal Flow = #1 Seal Leakoff Flow + #2 Seal Leakoff Flow
→Exceeding Limits on the chart below requires:
→reactor trip
→stopping affected RCP
→closing the seal leakoff valve 3-5 mins after pump trip
Note: #2 Seal Leakoff Flow is assumed to be 1 gpm as long as “ANY SEAL 2 LEAKOFF FLO HI”, u-ALB-5A, window 3.2 is DARK.
21
Q
Tech Spec 3.4.2 Minimum Loop Temp for Criticality
A
TS 3.4.2 Minimum loop temp for criticality is ≥ 551°F, or be in MODE 2 with k-eff < 1.0 within 30 min
22
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.
23
Q
Define reflux boiling
A
Reflux boiling is characterized by boiling core water and condensing steam in the SG with flow back through the Hot Legs.
24
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
25
What actions should be taken if PRT temperature is quickly rising?
In the case of PRT temperature getting too high, use the RCDT to recirculate the contents and transfer heat to CCW via the RCDT heat exchanger
26
Where do the PZR Spray Lines tap off from?
→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
27
What does PZR Manual Bypass flow allow?
→ ~1 gpm of continuous spray flow
→prevents thermal shock to the spray nozzle
→keeps chemistry & boron concentration at equilibrium with the RCS
28
The Subcooled Margin Monitor (SMM) compares...
...wide range RCS pressure indication with the highest CET temperature and RCS hot and cold leg temperatures.
29
PZR Heaters Group A&B number of heating elements & capacity
→21 heater elements each
→heat capacity of 485KW.
(Can be operated at the RSP, TS 3.4.9 requires 2 heater groups >150 KW capacity each)
30
What are the secondary functions of the RCS?
→remove heat generated in the fuel due to fission product decay following a plant shutdown
→act as a carrier for soluble neutron poison (boron)
→act as second barrier against fission product release to the environment
→improve neutron economy by acting as a reflector
→increase probability of fission by moderating the neutron energy level to that of a thermal state
31
If DC Control Power to an RCP is lost...
→RCP will remain running
→RCP can't be tripped electronically
→RCP can only be tripped manually
32
At what temperature/flow do the RCP Thermal Barrier return lines isolate?
→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)
33
Pressurizer PORV basic facts
→two 3" power operated relief valves (PORVs)
→u-PCV-0455A and u-PCV-0456
→relieve steam from top of PZR at setpoint of 2335 psig
→each PORV has a 210,000 lbm/hr relief capacity
→pneumatic actuators powered by compressed nitrogen
→discharge to common line routed to PRT
→designed to minimize challenges to PZR safety valves and are used for LTOP
34
What are the automatic trips for the PZR control and backup heater supply breakers?
→SI
→low PZR level (17%)
→bus undervoltage
35
Pressurizer Pressure Control Basics
(Be familiar.)
36
What provides RCS Level Indication?
→two identical probe assemblies that detect the presence of liquid or vapor at eight discrete elevations above the core plate
→thermocouples detect presence of a void in the upper vessel head
37
Charging Flow - Letdown Flow - Total Seal Leakoff Flow = ?
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.
38
Three RCS Loop Flowmeters on each intermediate leg
→How many low pressure transmitters are there per leg?
→How many high pressure transmitters per leg?
→What happens if a low pressure transmitter fails?
→What happens if a high pressure transmitter fails?
→3
→1
→one channel fails
→all three channels fail
39
Tech Spec 3.4.3 RCS Pressure and Temperature Limits
RCS pressure, RCS temperature, and RCS heatup and cooldown rates shall be maintained within the limits specified in the PTLR (at all times)
Requirements not met in Modes 1-4
→restore parameters to within limits within 30 minutes AND
→determine RCS is acceptable for continued operation within 72 hrs
Requirements not met NOT in Modes 1-4
→initiate action to restore parameters to within limits immediately AND
→determine RCS is acceptable for continued operation prior to entering Mode 4
40
What are the Tech Specs for RCS Loop Operability in different Modes?
41
Tech Spec 3.4.9 Pressurizer Operability
The pressurizer shall be OPERABLE (MODES 1-3) with:
→Pressurizer water level ≤92%; and
→two groups of pressurizer heaters OPERABLE with the capacity of each group ≥150kW
42
Tech Spec 3.4.10 Pressurizer Safety Valves Operability
Three pressurizer safety valves shall be OPERABLE with lift settings ≥2410 psig and ≤2485 psig (±1%)
(Modes 1-3 and Mode 4 with all RCS cold leg temps > 320° F)
If one PZR safety is inoperable, restore valve to operable within 15 minutes.
43
Tech Spec 3.4.11 PORV Operability
Since PORVs are not assumed safety function, plant operation can be continued with PORVs isolated by their block valves if they are capable of being manually operated from the Control Board H/S
44
Tech Spec 3.4.13 RCS Operational Leakage
RCS operational leakage shall be limited to:
→no pressure boundary leakage
→1 gpm unidentified
→10 gpm identified (within makeup)
→150 gpd primary to secondary through any 1 SG
45
Tech Spec 3.4.14 RCS Pressure Isolation Valve (PIV) Leakage
Leakage from each RCS PIV shall be within limit
NOTE: leakage must be verified within 24 hours following check valve actuation due to flow through the valve (SR 3.4.14.1)
46
Tech Spec 3.4.15 RCS Leakage Detection Instrumentation
The following RCS leakage detection instrumentation shall be OPERABLE (Modes 1-4):
→one containment sump level and flow monitoring system
→one containment atmosphere particulate radioactivity monitor
→one containment air cooler condensate flow rate monitor or one containment atmosphere radioactivity monitor (gaseous)
If all required monitors inoperable, enter LCO 3.0.3 immediately.
47
Tech Spec 3.4.16 RCS Specific Activity
The limits on specific activity of the RCS ensures that the resulting 2-hour doses at the site boundary will not exceed a small fraction of the federal limits following a SGTR coincident with a loss of offsite power.
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
→If I-131 > 60 μCi/g, be in MODE 3 in 6 hours
→Dose Equivalent Xe-133 spec is ≤ 500 μCi/g
48
TR 13.4.14 RCS Pressure Isolation Valves
List of Valves
49
Tech Spec 3.4.1 RCS Pressure, Temperature, and Flow Departure from Nucleate Boiling (DNB) Limits
→One or more RCS DNB parameters not within limits: restore RCS DNB parameters to within limits within 2 hrs
→Measured RCS flow not within limits: maintain thermal power less than 85% RTP immediately
50
When are the RCS loops considered NOT filled?
RCS loops are considered NOT filled when:
→Unit 1: RCS level ≤872'10" (≈35% cold calibrated PZR level)
→Unit 2: RCS level ≤866'3" (≈17% cold cal PZR level)
OR
→prior to performance of RCS vacuum fill operations following operation below 35% (17% U2) cold cal PZR level
NOTE: The SGs shall not be considered as reliable heat sink during natural circ c/d when RCS is depressurized below 100psig
51
What is the RCS pressure safety limit?
2735 psig
52
When do the PZR safeties lift?
2460 psig
53
When does the reactor trip on PZR high pressure (or RCS overpressure)?
2385 psig
(2/4 channels)
54
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.
55
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)
56
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
57
What is normal operating RCS pressure?
2235 psig
58
When do PZR backup heaters turn on?
When do PZR backup heaters turn off?
on: 2210 psig
off: 2218 psig
59
At what pressure are PORVs blocked?
2185 psig
→channel 457 feeds PCV-455A
→channel 458 feeds PCV-456
60
When does P-11 happen?
1960 psig
→PZR SI block permissive
→2/3 channels
→channels 455, 456, 457
61
When does the reactor trip on PZR low pressure?
1880 psig
(2/4 channels)
62
When does SI actuate on PZR low pressure?
1820 psig
(2/4 channels)
63
Which channel is PZR spray driven by?
the top channel
64
Why do the RCPs have flywheels?
→keeps rotating after loss of power
→helps establish natural circ
→pawls stop reverse flow in stopped pumps
65
What does CCW cool in the RCPs?
→motor air cooler
→bearing lube oil reservoir coolers
→thermal barrier HX
→limits heat from RCS to pump bearing and shaft
66
RCP Shutdown Seals
→between seals 1 and 2
→passive, thermally actuated seal ring
→limits leakoff to <1 gpm following loss of all seal cooling
→actuates when seal leakoff temp is 260°-320° F
67
Normal RCS Parameters:
RCS Volume
Unit 1: 95,000 gal
Unit 2: 91,000 gal
68
Normal RCS Parameters:
RCS Flowrate
Unit 1: 403,700 gpm
Unit 2: 408,000 gpm
69
Normal RCS Parameters:
RCS Pressure
2235 psig
70
Normal RCS Parameters:
T-hot
Unit 1: 618
Unit 2: 620
71
Normal RCS Parameters:
T-cold
Unit 1: 560
Unit 2: 559
72
Normal RCS Parameters:
T-avg
Unit 1: 557-585.4
Unit 2: 557-589.2
73
Normal RCS Parameters:
PZR Level
25% - 60%
74
Is the High PZR Pressure (High RCS Pressure) Rx Trip always available?
What about the Low PZR Pressure Rx Trip?
High Pressure: yes, always available
Low Pressure: only above P-7 (above10% power)
75
What are the must-know RCS connections?
→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
76
What percentage of core flow is available to the core itself?
94%. The remaining 6% is core bypass flow.
77
Rx Vessel O-ring leakage is routed to the...
RCDT (identified leakage)
78
Which Rx Vessel O-ring seal is normally in service, i.e. open?
the inside ring
→Isolation valve for inside, uRC-8069B, O-ring normally open
→Isolation valve for outside, uRC-8069A, O-ring normally closed
→Valve u8032 provided downstream of manual isolations; normally open
(u8032 powered from uD2-3, fails open on loss of power)
79
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)
80
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.
81
What do neutron panels do?
provide neutron shielding for parts of the Rx vessel closest to the core in order to reduce neutron embrittlement
(could be different words used for neutron panels, e.g. thermal shield or similar)
82
Rx Vessel closure head vent penetration
1" diameter, vents non-condensable gases which may occur during natural circ or post-accident
2 vents in series
83
At what approximate temperature does ceramic fuel melt?
5080° F
84
What is the safety limit to the calculated fuel centerline temperature?
U1: 4700° F
U2: 5080° F at BOL, decreasing 9° F per 10,000 MWD/MTU Burnup
(U1 to change to be in line with U2 after 1RF24)
(based on remaining well under fuel melting temp)
85
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)
86
How to the Reactor Vessel O-Rings work?
→two self-energizing o-rings
→part of the RCS pressure boundary
→small holes allow pressurized water to expand the o-rings and seal them
87
How many fuel assemblies in the Rx Vessel?
How many control rods?
→193 fuel assemblies
→53 control rods
88
Tech Spec 2.1.1 Core Operating Safety Limits
→Modes 1 and 2, The departure from nucleate boiling ratio (DNBR) shall be maintained > the 95/95 DNB (95% probability at a confidence level of 95% that the hottest fuel rod is not in DNB)
→Modes 1 and 2, Peak fuel centerline temp. shall be maintained <4700°F (U1) or less than 5080° F at BOL, decreasing 9° F per 10,000 MWD/MTU Burnup. DNB assumptions for 1.30 DNBR
→If violated, restore compliance and be in Mode 3 in 1 hour.
Staying within the temp/press curve in COLR ensures acceptable DNBR is maintained
(If safety limit is violated restart must be authorized by NRC. Shutdown driven by TS → report to NRC within 4 hours.)
89
Tech Spec 2.1.2 RCS Pressure Safety Limits
→Modes 1,2,3, 4 and 5, ≤2,735 psig, based upon Turbine trip w/o Rx Trip
→If violated in mode 1 or 2 restore and be in mode 3 in 1 hour.
→If violated in mode 3, 4, or 5, restore compliance within 5 minutes.
PZR Safeties, SG Safeties and Hi Press Trip ensure safety limit not exceeded.
(If safety limit is violated restart must be authorized by NRC. Shutdown driven by TS → report to NRC within 4 hours.)
90
IPO-003A
During initial startup of each fuel cycle, before exceeding 20% Thermal Rated Power, after extended low-power operation (>27 days)...
→no single step increase in power shall exceed 3% full reactor power
→the rate of reactor power increase between 40% and 100% of full power should be ≤3% per hour
91
Control rod guide thimbles have a ______________ inner diameter at the top and ____________ at the bottom. This is for...
larger; smaller
...rapid control rod insertion which allows water to escape as rods are inserted; also creates a dashpot effect at the bottom of travel to slow the rods
92
Fuel design clad temperature is limited to _____________.
This is because...
2200° F
...zirc water reaction becomes auto-catalytic at 2600° F, and the exothermic reaction exceeds ECCS capability
93
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)
94
Tech Spec 3.4.3 RCS Pressure and Temperature (P/T) Limits
RCS pressure, RCS temperature, and RCS heatup and cooldown rates shall be maintained within the limits specified in the PTLR at all times.
Requirements not met in Mode 1-4:
→Restore parameter(s) to within limits within 30 minutes AND
→Determine RCS is acceptable for continued operation within 72 hrs
Requirements not met NOT in Mode 1-4:
→Initiate action to restore parameter(s) to within limits immediately AND
→Determine RCS is acceptable for continued operation prior to Mode 4
95
Tech Spec 3.4.12 Low Temperature Overpressure Protection (LTOP) System
An LTOP system shall be OPERABLE with a maximum of zero Safety Injection pumps and two charging pumps capable of injecting into the RCS and the accumulators isolated and ONE of the following pressure relief capabilities:
→two PORVs with lift settings within limits specified in the PTLR
→two RHR suction relief valves with setpoints ≥436.5 psig and 463.5 psig
96
Tech Spec 3.4.13 RCS Operational LEAKAGE
RCS operational LEAKAGE shall be limited to:
→no pressure boundary leakage
→1 gpm unidentified leakage
→10 gpm identified leakage
→150 gallons per day primary to secondary leakage through any one steam generator
97
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
98
RVLIS Light Setpoints
→if thermocouple ΔT >200°F, then light goes out
→if thermocouple ΔT <100°F, then light is on
99
CCM Operability
Tech Spec 3.3.3 requires 2 operable CETs per Train, per Quadrant (16 total)
→verify at least 2 Train A & B CETs per quadrant available with < 75° F difference
→in addition, 5 CETs per train operable (at least on CET per quadrant and one additional CET in the center of the core that is different from the first four)
100
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
101
CCM SMM Train A Inputs
→25 CETs (auctioneered highest)
→T-hot Loops 1&2
→T-cold Loops 3&4
→PZR NR Pressure PT-0455
→PAM WR Pressure Thimble Pressure PT-3613 (loop pressure)
102
CCM SMM Train B Inputs
→25 CETs (auctioneered highest)
→T-hot Loops 3&4
→T-cold Loops 1&2
→PZR NR Pressure PT-0458
→PAM WR Pressure PT-403 (loop pressure)
103
How does CCM utilize data from CETs?
The highest valid CET signal is used and displayed.
104
With subcooling less than 25°F and less than 11" level above the core plate and core exit thermocouples greater than 750°F...
actions to restore core cooling capability are required.
105
Shutdown Margin Monitor Inputs (4)
1. Highest CET
2. RCS Loop RTD temperatures
3. RCS Loop pressures
4. PZR pressure
106
What are the power supplies for CCM & RVLIS?
→Train A/B CCM powered from uEC5/uEC6
→Train A/B RVLIS powered from uEC5/uEC6
107
What are the power supplies for the CCM alarms?
Unit 1:
→Train A: XED1-1
→Train B: XED2-1
Unit 2:
→Train A: 2ED1-1
→Train B: 2ED2-1
108
PS-5385/5385A (upstream of PCV-131) provides local pressure indication and HELB alarm at...
≤ 200 psig
109
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.
110
Letdown HX Outlet Temp
95°F
(inlet temp is 260° F)
111
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
112
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 RCP seal
113
The CCP alternate miniflow relief valves recirc to where?
RWST
(lift at 2200 psig)
114
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.
115
How does PDP speed fail on loss of air?
to its maximum speed
(98 gpm)
116
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.
117
PDP Trips
→Train A SI (breaker is load shed/shunt tripped)
→Low Lube Oil Pressure (4 psig, >90 sec after pump start)
→Undervoltage
→Overcurrent
118
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
119
How do 8149A/B/C Orifice Isolation Valves operate?
120
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
121
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
122
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%)
123
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.)
124
→8145 Aux Spray should not be used when...
→8145 Aux Spray shall not be used when...
→ΔT exceeds 320° F between charging out of Regen Hx and PZR temp
→ΔT exceeds 625° F
125
VCT Level Control (Level Channel 112) makeup start and stop setpoint
→Makeup starts 46%
→Stops at 56%
(10% level ≈ 200 gal)
126
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
127
RCS Limits on Letdown Flow (per # of demins)
→ ≥500°F in RCS, limit letdown flow to 140 gpm
→ <500°F w/1 demin in service, limit flow to 170 gpm
→ <500°F w/2 demins in service limit flow to 195 gpm
128
Do Hagan controllers work automatically?
No.
129
What is the power supply for the PDP?
uEB1
130
Where does Normal Letdown tap off of?
Loop 3 intermediate leg
131
Where does Excess Letdown tap off of?
Loop 1 Intermediate Leg
132
What happens if TCV-4646 (Letdown HX CCW outlet valve) fails?
→fails open
→will cool letdown and might cause dilution event
133
What is the normal flow through the Seal Water Heat Exchanger?
72 gpm
(60 gpm CCW miniflow plus 12 gpm RCP seal return)
134
FT-132 (upstream of PCV-131) provides an alarm for excess letdown flow at...
140 gpm
(potential of channeling in demins)
135
What are the CCP auto-starts?
→train associated SIS start signal
→train associated BOS start signal
136
What are the CCP automatic trips?
→safeguards bus undervoltage
→86M motor lockout
137
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
138
Letdown Relief Valve 8117 Basic Facts
→relieves at what pressure?
→design flow
→relieves to
→600 psig
→195 gpm
→PRT
139
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)
140
CCP High Head Safety Injection
→Both CCPs start
→PDP trips
→CCP suction from RWST opens; suction from VCT closes
→normal miniflow closes; alternate miniflow to RWST opens
→normal charging path closes; SI path opens
→Letdown isolates
→RCP Seal Water Return isolates ("Phase A")
→flow directed to all 4 cold legs
141
TS 3.5.2 ECCS Operating (MODES 1-3)
Two ECCS trains shall be OPERABLE (Modes 1-3)
→ECCS trains are CCPs, SIPs, RHRPs and piping; accumulators and RWST are not considered part of ECCS for this LCO
→In Mode 3, LTOP system is allowed to prevent ECCS pumps from injecting for up to 4 hours or until all RCS cold leg temps >375° F, whichever comes first
→all ECCS subsystems are credited for LOCA
142
TS 3.5.3 ECCS Shutdown (MODE 4)
One ECCS train shall be OPERABLE (Mode 4)
→an RHR train is still operable during alignment for decay heat removal if it's capable of being manually realigned to ECCS
→if ECCS RHR subsystem inoperable, initiate action to restore immediately
→if ECCS CCP subsystem inoperable, restore within 1 hour
143
TS 3.5.5 Seal Injection Flow (MODES 1-3)
Reactor Coolant Pump seal injection flow shall be ≤40gpm with RCS pressure ≥2215psig and ≤2255psig and the charging flow control valve full open
Modes 1-3
144
TS 3.6.3 Containment Isolation Valves (MODES 1-4)
Each containment isolation valve shall be OPERABLE (MODES 1-4)
NOTE: Not applicable to Main Steam Safety Valves (MSSVs), Main Steam Isolation Valves (MSIVs), Feedwater Isolation Valves (FIVs), and associated Bypass Valves, and Steam Generator Atmospheric Relief Valves (ARVs).
One or more penetration flow paths with two containment isolation valves inoperable:
→isolate the affected penetration flow path by use of at least one closed and de-activated automatic valve, closed manual valve, or blind flange within 1 hour
(except for containment purge, hydrogen purge, or containment pressure relief valve leakage not within limit)
145
TS 3.4.16 RCS Activity (MODES 1-4)
Basis - SGTR
The limits on specific activity of the RCS ensures that the resulting 2-hour doses at the site boundary will not exceed a small fraction of the federal limits following a SGTR coincident with a loss of offsite power.
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
→If I-131 > 60 μCi/g, be in MODE 3 in 6 hours
→Dose Equivalent Xe-133 spec is ≤ 500 μCi/g
146
TR 13.1.31 Boron Injection System Operating (MODES 1-4)
Two OPERABLE paths:
→One BAT, one BA transfer pump or Gravity Feed, and one CCP
→RWST, Train A RWST Valve, Train A CCP
→RWST, Train B RWST Valve, Train B CCP
Note: Mode 4 - PDP can be used in place of CCP
147
TR 13.1.32 Boron Injection Systems Shutdown (MODES 5-6)
One OPERABLE path
If using RWST as borated water source in Modes 5 & 6, required to be operable with:
→minimum level of 24% (15% in Mode 6 with head removed and SIP injection path)
→minimum boron concentration of 2400 ppm
→minimum solution temperature of 40° F
148
Can you draw CVCS?
149
What are the three positions for the 1/u-LCV-0112A VCT Level Control Valve Handswitch?
→VCT: flows directly to VCT (will NOT auto-divert to RHUT)
→AUTO: allows valve position to be controlled by two VCT level transmitters, u-LT-0112/0185
→HUT: flows directly to RHUT
We maintain in VCT position with an alarm for if handswitch is out of position or if valve position has changed to divert letdown to RHUT.
150
When does the VCT low level alarm come in?
16%
151
When does the VCT high level alarm come in?
70%
152
When does letdown start automatically diverting some flow to the RHUT?
62% level in VCT
153
When is letdown flow being fully diverted to the RHUT?
98% level in VCT
(also high-high level alarm)
154
How much flow goes through each letdown orifice?
→A (top) 45 gpm
→B (middle) 75 gpm
→C (bottom) 75 gpm
155
PCV-115 VCT Vent to GWPS auto closes on...
→low VCT pressure of 14 psig
→both GWPS recombiner O2 supply valves close
→low waste gas compressor suction pressure
156
VCT Relief Valve 8120
→lifts at 75 psig
→relieves to RHUT
157
How does HCV-182 fail?
(seal injection flow control)
→fail open AOV
158
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
159
What powers u-8104 (Emergency Borate Valve)?
→uEB4-1
→Controlled by either MCB or RSP
→no automatic functions
160
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
161
Per the TRM, heat tracing must maintain temperature
Per TRM must maintain piping >65°F
162
Does FCV-110A fail open or closed?
Fail Open AOV (continue to manual emergency borate)
163
Control Modes
1. Off
2. Auto
3. Borate
4. Dilute
5. Alternate Dilute
6. Manual
NOTE: control relays powered from PC1, on loss of PC1 system can be manually operated to provide makeup flow.
164
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
165
BAT Tanks
→Useable vol 43,000 gals
→TRM min concentration of 7,000 ppm
→TRM minimum temperature of 65°F
→Room heaters set at 90°F
→Remote and local level and temperature indication, remote indication on U1 only
166
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
167
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
168
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
169
BA Flow Deviation Alarm
Desired flow is not obtained within ±1 gpm within 25 seconds. If occurs, it closes FCV-110B and FCV-111B.
170
When a blended flow of a concentration >1600 ppm is desired...
the maximum boric acid flow should NOT be expected to exceed 27 gpm. Therefore, a Manual Blended Makeup is required to achieve boron concentration >1600 ppm.
171
Emergency Boration Flowpaths
Preferred Emergency Boration
→BAT to BA transfer pump, through u-8104 to suction of CCPs
→75 gpm
172
Emergency Boration Flowpaths
Manual Emergency Boration
→BAT to BA transfer pump, through FCV-110A, through uCS-8439 to suction of CCPs
→36 gpm
173
Emergency Boration Flowpaths
Gravity Feed Emergency Boration
→gravity feed from BAT through u-8509 to suction of CCPs
174
Emergency Boration Flowpaths
Alternate Emergency Boration
→BAT to BA transfer pump, through FCV-110A, through blender, through FCV-110B to suction of CCPs
→27 gpm
175
BAT and RWST min level (MODES 1-4)
→BAT must be >50%
→RWST must be >95%
→per TR 13.1.31
176
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.)
177
TR 13.1.31 Boron Injection System Operating (MODES 1-4)
Two OPERABLE paths (2 out of the 3 paths below):
→1 BAT, BA transfer pump or Gravity Feed & CCP
→RWST, Train A RWST Valve, Train A CCP
→RWST, Train B RWST Valve, Train B CCP
Note: Mode 4 - PDP can be sued in place of CCP
178
TR 13.1.32 Boron Injection Systems Shutdown (MODES 5-6)
One OPERABLE path
If using RWST as borated water source in Modes 5 & 6, required to be operable with:
→minimum level of 24% (15% in Mode 6 with head removed and SIP injection path)
→minimum boron concentration of 2400 ppm
→minimum solution temperature of 40° F
179
The chem add lineup has an orifice to limit chem add flow to...
→2 gpm
→Used to add chemicals for pH control and O2 scavenging
→RMUW pumps provide driving force
180
Per ABN-107, Attachment 7, for stuck control rods...
...borate 1800 gallons of 7000 ppm boric acid OR equivalent for EACH control rod not fully inserted.
181
Which dilution control mode gives the quickest reactivity response?
alternate dilute
(can be aligned to bottom of VCT)
182
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
183
How do you calculate boric acid flow for blended flow?
BA Flow x BAT conc = TOTAL Flow x RCS conc
184
If TIS-382 fails high...
TCV-129 diverts to the VCT and bypasses the letdown demins.
185
Per SOP-106 the max allowable flow(s) through BTRS demins...
is 164 gpm for one, and 300 gpm for two.
186
If BTRS is not isolated and the plant trips...
we could cause an inadvertent dilution of the RCS, as flow is still passing through the demins.
187
What is the setpoint for TE-381?
TE-381 alarms @ 150°F
188
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.
189
What is the normal lineup for BTRS when in service?
Used for EOL dilution and crud burst cleanup (requires IPTE to use).
→Beds 1-2 used for crud burst
→Beds 3-5 used for dilution (100 ppm to 0 ppm)
190
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
191
What is the purpose of the u-7054 BTRS isolation valve?
Must be manually closed after entry into emergency procedures. Only directly addressed in FRS-0.1A(B) RESPONSE TO NUCLEAR POWER GENERATION/ATWT
192
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
193
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)
194
What is the function of PZR handswitch PS-455G?
Selects what pressure channel feeds the PZR chart recorder on CB-05.
195
PZR Handswitch PS-455F top channel feeds what?
PZR Handswitch PS-455F bottom channel feeds what?
→Top: PORV PCV-455A
→Bottom: PORV PCV-456
196
What is the function of PZR Handswitch PS-455F?
3 position selector switch used to select which 2 channels will be used for pressure control.
197
PZR Pressure Hi Alarm setpoint
2310 psig
(also spray full open)
198
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)
199
'Pressurizer Pressure Deviation High' alarm comes in at what pressure?
>75 psig above set point
(2310 psig)
200
Pressurizer pressure low alarm and turning on backup heaters actuate at what pressure?
>25 psig below setpoint
(2210 psig)
201
What does PK-455B feed?
What does PK-455C feed?
→PK-455B: PZR Spray valve PCV-455B, loop 1
→PK-455C: PZR Spray valve PCV-455C, loop 4
202
At what pressure do PORVs open?
At what pressure do PORVs close?
Open: 2335 psig
Close: 2315 psig
(blocked from opening below 2185 psig)
203
How are the PORV accumulators sized?
Designed to allow cycling 100 times in a 10 minute period
204
If a conflict occurs between Level Control and Pressure Control which takes priority?
Level control is dominant
205
PORV rated flow
210,000 lbm/hr
206
When do pressurizer heaters energize?
→Decreasing pressure (PK-455A output at ~42%)
→Pressurizer Level 5% above program
207
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.
208
What does LK-459 provide control for?
→PDP speed
→FCV-121 position
209
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.
210
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%
211
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.
212
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.
213
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
214
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
215
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.
216
What occurs if a PZR bottom level control channel fails high with no operator action?
→Hi level alarm (70%)
→1 of 3 coincidence on Rx trip on Hi-Hi Level (92%)
217
Which level transmitters are 'Post Accident Environmentally Qualified'?
LT-459/460/461
218
What is the function of LR-459?
Used to select which level channel inputs into the level recorder on CB-05
219
What is the function of LS-459D?
→Used to select which channels provide control functions.
→Normal position is 459/ 460.
220
What is the function of LT-462 and LT-459F?
→provide level indication only
→no control functions.
221
Per ABN-705 in response to a PZR PT failure...
PK-455A is taken to manual and then an alternate channel is selected if failed channel in control, this is to mitigate the possibility of a PORV opening due to the Proportional/Integral function of the controller
222
PZR Safety design
Designed for the maximum surge rate resulting from a complete loss of steam flow to the main turbine, w/o a reactor trip, automatic control response (rod control, condenser steam dumps, pressurizer PORVs, etc.) or operator action.
Peak RCS pressure is limited to less than 110% of design pressure by the safeties during a design basis transient.
223
PORV and Block Valve Power Supplies
→PORVs: train related 125 VDC
→Block Valve u8000A: uEB3-2
→Block valve u8000B: uEB4-2
224
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)
225
PORV Accumulator sizing
→sized for cycling 100 times in 10 mins
→located CTMT 905'
→alarm provided on MCB for <90 psig in Accumulator
226
Heater Control Group after trip
Control Group C H/S must be taken to ON to reclose supply breaker after trip
227
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
228
PZR Heater Power Supplies
→A: uEB3
→B: uEB2
→C: uEB1
→D: uEB4
"CBAD" for uEB1, 2, 3, then 4
229
PZR Heatup and Cooldown Limits
→100° F per hour heatup
→200° F per hour cooldown
(minimizes fatigue stress in accordance with ASME requirements)
230
1 Hour or Less PZR TS
→3.4.10 Pressurizer Safety Valves - 15 minutes
→3.4.11 Pressurizer Power Operated Relief Valves (PORVs) - 1 hour
231
Low Level in a Reference Leg of the PZR Level Detector channel can be identified by...
...comparing the level channel indications.
If a reference leg leaks, its PZR level channel will read erroneously high.
232
If steam inside containment significantly raises ambient temperature, how might that affect PZR level indication?
The water in the reference leg could boil away, causing level indication to read erroneously high. Could potentially affect all channels at the same time.
233
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%
234
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%.
235
What is the thumb rule for knowing demand vs what will happen in the pressurizer?
→If demand ↑, spray is at the top, so spray turns on.
→If demand ↓, heaters are at the bottom, so heaters turn on.
236
What level does the Hi PZR Level Alarm come in?
70%
237
What level does the Hi PZR Level Rx Trip come in?
92%
238
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
239
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%)
240
Temperature at which PORVs automatically arm for LTOP
≤350° F
(automatically disarm >350° F)
241
How many PORVs are required to prevent overpressure?
Only one
242
A single PORV has adequate relief capability to prevent overpressure if the transient is limited to:
1. starting an idle RCP with secondary water temperature
≤ 50°F above RCS CL temperature
2. the start of 2 charging pumps and their injection into a water solid RCS
243
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.
244
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.
245
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
246
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
247
LTOP is required when any CL temperature is...
(TS 3.4.12)
≤ 320°F
248
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
249
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
250
When is LCO 3.0.4.b not applicable regarding LTOP?
When entering MODE 4
251
Which PORV opens faster on NOP/NOT overpressure? Which PORV opens faster on LTOP actuation?
Overpressure: PCV-455A, due to the PI Controller
LTOP: They open simultaneously
252
What are the LTOP PORV setpoints for different temperatures?
253
Why do we add Argon to the VCT?
→in VCT for primary to secondary leak detection
→improves detection in Condenser Off Gas Radiation Monitor
254
STA-609 Fluoride and Chloride Action Levels
Action Level 1: >50ppb
Action Level 2: >150ppb
Action Level 3: >1500ppb
(each, not total)
255
Technical Requirements Manual Fluoride and Chloride Limits
→Steady State Limit: ≤0.15ppm
→Transient Limit: ≤1.5ppm
(n/a when RCS defueled)
256
STA-609 Dissolved Oxygen Action Levels
Action Level 1: >5ppb
Action Level 2: >100ppb
Action Level 3: >1000ppb
257
TRM Dissolved Oxygen Limits
→Steady State: ≤ 0.1ppm
→Transient: ≤1.0 ppm
(n/a when T-ave ≤ 250° F)
258
Action Level 1
→Initiate corrective actions to return the parameter within the Action Level 1 value range within seven (7) days.
→make appropriate notifications
Escalation: Technical Evaluation, Plan and Upgrade to Action Level 2
(Appropriate notifications can be to RP, Ops, and/or Core Performance Engineering.)
259
Action Level 2
→Restore parameters to within Action Level 2 limits within 24 hours.
→make appropriate notifications
Escalation:
→initiate orderly unit shutdown to Cold Shutdown
→may return to power if back in spec before shutdown completed
(Appropriate notifications can be to RP, Ops, and/or Core Performance Engineering.)
260
Action Level 3
→An orderly unit shutdown should be initiated immediately, with reduction of coolant temperature to < 250°F as rapidly as other plant constraints permit.
→make appropriate notifications
Note: May return to power if back in spec before shutdown completed
(Appropriate notifications can be to RP, Ops, and/or Core Performance Engineering.)
261
What kind of Lithium do we add and why?
→lithium hydroxide
→raises pH
→99.9% enriched Li-7
(Li-6 is a strong neutron absorber)
262
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
263
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)
264
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
265
PZR Instrument number designations
→they all begin with 4
→second number = which loop
→if 3rd number is 3 = wide range
→A = T-hot
→B = T-cold
→F = RSP instrument
266
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.
267
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
268
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
269
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)
270
T-ave Defeat Switch Operation
T-ave defeat switch is different in that when a channel is taken to defeat it is replaced by the previous channel (4 replaces 1, 1 replaces 2 etc.) such that 1 channel provides 2 inputs.
Note: if the channel that replacement channel reads significantly higher/lower than the failed channel, then it will affect both the T-ave and Ave T-ave indications and could cause changes to the plant accordingly.
271
Describe N-16 and how it varies with temperature
Although the half life of N-16 is short (7.11 sec) the loop travel time is ~10 secs therefore the N-16 detector not only detects the newly formed N-16 gammas but also those from the previous cycle (99% decayed away after 47 secs) therefore the detector is calibrated to compensate for this.
Additionally, the amount of N-16 gammas corresponds to the density of the water since the denser the water the more N16 therefore more gammas detected. To compensate for those times when the water temperature is not on program T-cold is input into the system to provide the density compensation.
272
N-16 Failure
If T-cold increases then gammas should decrease, therefore compensation increases N-16 indication since T-cold increasing corresponds to an increase in power (N-16 indication follows failure mode of T-cold)
273
OP N-16 Rx Trip Setpoint
112%
(kW/ft)
274
C-4 Setpoint & Actions
Setpoint:
N-16 within 3% of OP N-16 trip setpoint on 2/4 channels.
Automatic Actions:
1. Rod Stop, all outward motion stops
2. turbine runback at ~200% per minute for 1.5 seconds, with a 28.5 second pause (equivalent to 10%/min power reduction)
3. runback continues until either the condition clears or power is <15%.
275
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)
276
C-3 Setpoint & Actions
Setpoint:
N-16 within 3% of OT N-16 trip setpoint 2 of 4 channels
Automatic Actions:
1. Rod Stop: all outward motion stops
2. turbine runback at ~200% per minute for 1.5 seconds, with a 28.5 second pause (equivalent to 10%/min power reduction)
3. runback continues until either the condition clears or power is <15%.
277
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
278
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
279
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
280
What is the purpose of OT N-16?
How do changes in inputs correspond to changes in OT N-16 setpoint?
Purpose:
to prevent exceeding DNB limits
Setpoint Changes:
→as pressure ↓, setpoint ↓ because closer to DNB
→as pressure ↑, setpoint ↑ because farther from DNB
→as temperature ↑, setpoint ↓ because closer to DNB
→, as temperature ↓, setpoint ↑ because farther from DNB
→as long as ΔI remains "inside the doghouse," then no penalties/changes; if not, then setpoint lowers
281
What is the purpose of the OP N-16 Trip?
→provides assurance of fuel integrity (kW/foot) under all possible overpower conditions, e.g. no fuel pellet melting and less than 1% cladding strain
→limits the required range for an over temperature trip
→provides a backup to the High Neutron Flux trip
282
What's the difference between the OP N-16 setpoint and the OT N-16 setpoint?
The OT N-16 setpoint changes based on inputs. The OP N-16 setpoint does NOT change.
283
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
284
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
285
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
286
Tech Spec 3.6.3 Containment Isolation Valves (CIVs)
→each CIV shall be OPERABLE (Modes 1-4)
→7126 & 7150
→7135, 7136, 1003 (level control & bypass CIVs)
→also FC on Loss of Air
287
What is notable about Manual Bypass valve u7135?
→goes around LCV-1003
→locked closed
→classified as a CIV
288
What is the purpose of the RCDT?
The RCDT is used to recirculate, drain, or aid in purification of the contents of the PRT, RCS Loops, SI accumulators, and Refueling Cavity.
289
The PRT can be aligned to be cooled by...
the RCDT using the Hx.
290
Where can RCDT flow go?
→RHUT
→SFP
→WHT
→PRT
291
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
292
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
293
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
294
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
295
Tech Spec 3.6.3 Containment Isolation Valves (CIVs)
→each CIV shall be OPERABLE (Modes 1-4)
→7126 & 7150
→7135, 7136, 1003 (level control & bypass CIVs)
→also FC on Loss of Air
296
What is notable about Manual Bypass valve u7135?
→goes around LCV-1003
→locked closed
→classified as a CIV
297
What is the purpose of the RCDT?
The RCDT is used to recirculate, drain, or aid in purification of the contents of the PRT, RCS Loops, SI accumulators, and Refueling Cavity.
298
The PRT can be aligned to be cooled by...
the RCDT using the Hx.
299
Where can RCDT flow go?
→RHUT
→SFP
→WHT
→PRT
300
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
301
Max Containment Pressure and Temp
→max design pressure: 50 psig
→max design temp: 280°F
(applies to the structure, not the inside atmosphere)
302
Basis for Max Containment Pressure and Temp
1. Serve as the outermost barrier in preventing the release of radionuclides to the environment, in the event of an accident.
2. Protect the NSSS and its auxiliaries from outside hazards.
3. Serve as a support structure for various components.
4. Act as part of the CPSES Biological Shielding.
5. Meeting design temperature and pressure ensures CTMT does not exceed allowable leakage
303
Purpose of Charcoal Filters
Charcoal filters are used to remove iodine from CTMT atmosphere
304
Purpose of Particulate filters
Particulate filters remove aerosols
305
Design criteria for Containment Ventilation Isolation valves
Containment Ventilation Isolation valves must be capable of being closed during reduced inventory in case RHR cooling is lost
306
10CFR100 Criteria
1. Exclusion area (2 hours):
< 25 R whole body
< 300 R thyroid
2. Low Population Zone (duration of accident):
< 25 R whole body
< 300 R thyroid
307
Hydrogen Generation Aluminum and Zinc Corrosion
The use of aluminum inside the containment is limited, but zinc can be found in both the paint used in containment and also the galvanizing process used in the duct work. The hydrogen generated from zinc is completed during the first day after the accident.
308
Containment Leakage Detection
CNTMT Sumps provide CNTMT SUMP FILL RATE INCREASE alarm if level increases by 5/8" over preset time, fill rate and total flow required by TS
309
Describe the response of the Containment Sumps to a Phase A signal
The containment isolation valves will close on a Phase A signal. Valve closure results in a pump trip.
310
CNTMT PRESS HI 1 alarm
→3.2 psig (1/3)
→2/3 channels provides SI (Channels 2-4)
311
CNTMT PRESS HI 2 alarm
→6.2 psig (1/3)
→2/3 generates MSL Isolation (Channels 2-4)
312
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
313
Containment Atmosphere Hydrogen Analyzers
→continuously monitor the hydrogen content of the containment atmosphere during normal plant operation →shall be operational within 30 minutes following a LOCA
314
Containment Pressure IR Channels
Channel 1 - 937
Channel 2 - 936
Channel 3 - 935
Channel 4 - 934
315
TS 3.6.3 CIV notes
→separate condition entry is allowed for each penetration flow path.
→during fuel movement containment penetrations are required to be isolated or tracked by a LCOAR or fuel movement must be suspended
316
TS 3.6.4 CTNMT Pressure
→ctnmt pressure must be maintained ≥-0.3 psig and ≤1.3 psig
→use pressure relief system to maintain
317
TS 3.6.5 CTNMT Temperature
→ctnmt average temp must be ≤120°F
→start additional CACRS to maintain
318
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)
319
How are the valves that close on Phase A different than the valves that close on Phase B?
Phase B valves are MOVs because Instrument Air to Containment is isolated on Phase A.
320
What do the black labels under MCB instruments mean?
used for Post Accident Monitoring (PAM) - they're rated for use in adverse conditions inside Containment after an accident
321
What is the range of the Containment pressure indicator on the MCB?
-2.5 to 2.5 psig
