Systems Exam 5 - Solid State Protection System (SSPS) Flashcards
(27 cards)
What does this relay or contact do?
33
position switch
(detects position of something)
What does this relay or contact do?
a
contact position follows breaker
(usually open when de-energized)
What does this relay or contact do?
b
contact position opposite of breaker
(usually closed when de-energized)
SSPS General Power Supplies
→each train of SSPS contains two dual voltage power supplies (15 and 48 volt)
→redundant supplies are auctioneered to form one 48 VDC and one 15 VDC bus
→Train A has two 15 VDC and two 48 VDC power supplies
→the loss of any of the four output voltages will give a General Warning Alarm on the Train and on the Main Control Board
SSPS Train Related Power Supplies
Train A:
→DC power supply comes from Input Bays 1 and 3 (uPC1 and 3)
→slave (output) relays powered from uPC1
→loss of uPC1 means Train A slave relays will NOT actuate
Train B:
→DC power supply comes from Input Bays 2 and 4 (uPC2 and 4)
→slave (output) relays powered from uPC2
→loss of uPC2 means Train B slave relays will NOT actuate
Note:
→48 VDC is for Master Relays
→15 VDC is for Testing Relays
→118 VAC is for Slave Relays
What inputs into SSPS?
→output from 7300
→NIS
→field contacts
SSPS Basic Process
→inputs go to Universal Logic Cards
→if coincidence is met, generates an output signal for either Rx Trip or ESF
→Rx Trip signals are sent to the UV Card, which de-energizes the UV Coils and Shunt Trip Relay, causing Rx Trip
→ESF Signals are sent to the Safeguards Driver Cards, which energize Master Relays, which then energize Slave Relays
→in some cases, the Slave Relays will input back into other Logic Cards to generate other logic (e.g. generating Rx Trip on an SI)
If SSPS is in TEST with the IEI Switch in INHIBIT…
→SI will NOT function with either an automatic or manual signal for that train
→a manual Rx Trip will still trip all closed Rx Trip breakers
→an automatic Rx Trip will open the unaffected Rx Trip and Bypass breakers (i.e. Train A being in “Test” will prevent RTA and BYB from opening)
Note: the RO should re-block all blocks via the Control Board during SSPS testing after Permissives and Memories but before IEI is returned to “Normal.” Otherwise, the blocks may not be in effect, so could result in a Rx Trip.
SSPS Input Error Inhibit Switch
→NORMAL - aligns ground path to allow system to operate normally
→INHIBIT - removes ground path from system and prevents circuits from actuating
→INHIBIT will not prevent Rx Trip; only prevents any external signals other than manual from being input into SSPS
→INHIBIT will still allow manual ESF for that train
Note: CVI input does not go through the Input Error Inhibit switch, so it is the only automatic actuation that will occur in “Inhibit.”
The P-4 signal in SSPS inputs to…
→inputs to the AUTO SI BLOCK circuit (Rx Trip breakers must be cycled closed in order to remove the block after the initial SI actuation)
→inputs to the Lo T-ave and P-4 Feedwater Isolation circuit
→inputs to the logic card that causes an SI or P-14 signal to seal-in Feedwater Isolation until P-4 is reset
Which P-4 signals do NOT go to SSPS?
Instead, they go directly from the Reactor Trip Switchgear to the applicable systems.
→the P-4 signal that trips the Main Turbine (either train’s P-4)
→the P-4 signal that places Steam Dumps into the Plant Trip Controller (Tr. B P-4)
→the P-4 signal that goes to the SER (either train’s P-4) to cause the PCIP “Rx Trip Perm P-4” window 1.5 to light
Rx Trip Breakers
On a Reactor Trip, the shunt trip relay will de-energize, which closes a Normally Open contact to energize the Shunt Trip Coil, which will forcefully trip the breaker
125 VDC uED1-1 or uED2-1 required for shunt coil to function
SSPS Undervoltage Output Card
→supplies current to undervoltage coil of the Reactor trip and bypass breakers of the rod control system
→on a loss of input voltage, the UV Card provides a ground path for the UV and Shunt Trip coils causing them to de-energize and therefore actuate
→ a 15 V Threshold Cutout Circuit monitors the 15 VDC supplied to the UV driver card and will stop the UV driver card from outputting 48 VDC if the 15 VDC bus drops to <12.7 Volts
Which SSPS input relays are “energized to actuate?”
In general, the Input Relays are de-energized to actuate except for:
→RWST Lo-Lo Level
→Hi-3 Containment Pressure
→P-6.
This is done to ensure that those actuations do not occur on a loss of power because they could have detrimental effects on the plant if actuated when not required.
SSPS General Warning
→Power Supply Loss: Either of the 48 VDC or either of 15 VDC
→Circuit card not properly inserted (except the Isolation cards A 503-506)
→MULTIPLEXER SWITCH in INHIBIT
→LOGIC A Switch NOT in the “OFF” position
→PERMISSIVES Switch NOT in the “OFF” position
→MEMORIES Switch NOT in the “OFF” position
→MASTER RELAY SELECTOR Switch NOT in the “OFF” position
→INPUT ERROR INHIBIT switch in the “INHIBIT” position
→ Bypass breaker connected and shut
→ MODE SELECTOR, slave relay test, switch in the “TEST” position (unless S604 is in MODE 5/6)
→Loss of 118 VAC power to either output cabinet
Note:
→a GW on the Train in test will cause a reactor trip if the opposite Train receives a GW for any of the above
→if below P-9 (<50%), there is no light on the first out panel
→if above P-9 (>50%) there is a first out light for “Reactor Greater than 50% Power Turbine Trip”
Do Bypass Breakers shunt trip?
Bypass breakers receive a shunt trip on a manual Rx Trip, but not with an automatic trip. (only receive UV trip with an automatic trip)
Rx Trip Breakers receive UV and shunt trip on both automatic and manual trips.
How do the Reactor Trip Breakers and Bypass Breakers send train related signals for SSPS General Warning as well as Reactor Trip?
SSPS General Warning:
→Train A Bypass Breaker gives a Train A General Warning
→Train B Bypass Breaker gives a Train B General Warning
Reactor Trips:
→Train A Rx Trip Breaker sends trip signal to Train B Bypass Breaker
→Train B Rx Trip Breaker sends trip signal to Train A Bypass Breaker
Why are Containment Spray / Phase B actuation hand switches unique?
Both switches must be turned to the actuate position at the same time for the actuation to take place.
(CB-02 or CB-07)
SSPS Multiplexer Test Switch
→ NORMAL - allows Train A or B to cause trip indication for the TSLB
→ INHIBIT - data from the associated train isn’t sent to multiplexer (prevents affected train from inputting to PCIP, TSLBs, and ALBs)
→ A + B - allows input from both trains to the multiplexer
→normally, one train is in “Normal,” and the other is in “A + B”
→TSLBs and PCIP window will blink if multiplexers don’t agree (i.e. 1 train of SSPS didn’t actuate)
SSPS Input Bays
→input from external systems first comes into the Input Bays
→bays are physically and electrically independent
→powered by associated protection channel (uPC1-4 for Bays 1-4)
→Input Bays supply power to respective channel field contacts for Turbine Trip (HP Stop & EHC Pressure), RCP UV, and RCP UF trips (when field contact trips, causes input relay to de-energize)
How are the Rx Trip hand switches on CB-07 and CB-10 different?
→both switches will trip the breakers
→switch on CB-10 will NOT close them; it can only trip
What happens if both trains of Bypass breakers are connected and closed at the same time?
→a Bypass breaker being connected and closed causes a General Warning signal on its associated train
→when closing a second Bypass breaker, the second breaker will close momentarily, which will cause a General Warning signal on the second train
→General Warning on both trains will cause a Rx Trip by de-energizing the UV trip coils on all Rx Trip and Bypass breakers and energize the shunt trip relays on the Rx Trip breakers
When a Rx Trip breaker is bypassed, is its associated protection train considered operable?
No
The First-Out annunciators are driven by…
…the Sequence Events Recorder (SER).
