RPS Flashcards
Tech Spec
3.5-1
Min degree of redundancy of 1 for RPS instruments. ON loss of min degree of redundancy, restore in how long or be in what in how many hours?
Restore in 1 hour
OR
Be in HSD in 6 hours
RPS
Purpose
Protects
Reactor core against fuel cladding failure
RPS Trip Scheme:
RC pressure low
basis
RCS pressure <1900#
Prevents flue clad damage (min DNBR)
RPS Trip Scheme:
Flux/delta flux/flow
Power> 1.08x % RC flow-imbalance
RPS Trip Scheme:
Power/pumps
> 55% pwr w/ 1 RCP per loop,
The reactor coolant system pressure shall not exceed what pressure when there are fuel assemblies in the reactor vessel. What is the design basis?
2750 psig
To not exceed 110% of 2500 psig (design maximum pressure)
RPS Trip Scheme:
Power/pumps
> 0% power loss of both RCPs
RPS trip scheme:
High power
RX >105.1%
RPS trip scheme:
RCS pressure high
RCS pressure >2355#
RPS trip scheme:
RC temp HIGH
RC temp > 618.8F
RPS trip scheme:
Reactor bldg. high
RB pressure > 4#
RPS trip scheme:
Anticipatory Rx trips
<75# FWP lube oil (95# reset)
RPS trip scheme:
Anticipatory RX trips
<4EH00# EHC pressure (500# reset)
RPS electronic trip signal is sent if:
Manual pushbutton on CC depressed
Both safety grade wide range RCS pressure transmitters >2500 psig
RPS
Energize or de energize to trip?
When relay on CRD supply bkrs?
De-energize to trip
UV relay on CRD supply bkrs
DSS
Energize or de-energize
How to trip?
De-energize to trip
61 gate drives
What system provides ATWS protection?
DSS
What is the basic RPS trip logic?
2 out of 4
What is diverse about DSS?
Energize to actuate, different signals, acts on 61 gate drivers
How does DSS actuate?
Energize to tells gate drivers to remove power to the SRPS
RPS de-energizes undervoltage coils of the CRD bkrs
Yes that’s true
How does this system work with malfunction?
If the A and C CRD didn’t work, do we trip?
No, then DSS will have to trip it
How does this system work with malfunction? If A and B CRD don’t work, did we trip the reactor?
Yes
DSS
Setpoints
(2 of them)
Manual DSS pushbutton (always press when we trip)
2 out of 2 RCS pressure >2500 psig
DSS
CT-3 fed from what power supply and what type?
1G 480 V
BOP
DSS
Is it operable during a loss of power?
Nope
RPS
How many channels of RPS, colors?
4 channels
A is red
B is green
C is yellow
D is blue (normal colors)
RPS Trip scheme basis:
Low rcs pressure
Prevents fuel clad damage (min DNBR)
RPS Trip scheme basis:
Flux/flow imbalance
Min DNBR and max linear heat rate
RPS Trip scheme basis:
Flux to RC pumps
Min DNBR
RPS Trip scheme basis:
Variable low press/temp
Min DNBR
RPS Trip scheme basis:
High power
Min DNBR and centerline melt by reactivity excursions too raped for press/temp response
RPS Trip scheme basis:
High RCS pressure
RCS safety limits (2750#) and startup accident (low power) or slow rod withdrawal (high power)
RPS Trip scheme basis:
High temp
Excessive core coolant temp exceeding FSAR assumption of 620 F
RPS Trip scheme basis:
High RB pressure
Protects against steam leak/LOCA that does NOT hit 1900# low pressure
RPS Trip scheme basis:
FWP anticipatory
Prevents challenging porv/safeties
RPS Trip scheme basis:
Turbine anticipatory
Prevents challenging PORV/safeties
Which NI’s are inputs for RPS, associated channel?
NI 5,6,7, and 8
5 = A
6 = B
7 = C
8 =D
Main turbine system signals
EHC oil press at what pressure does it open and what pressure does it reset?
400 psi and 500 psi
Where does RPS power come from?
Channel A-D powered by vital bus A-D, respectively
RPS
Manual bypass
What type of switch?
Key switch
RPS
Manual bypass
If in bypass, the trip relay stays what?
Trip relay energized
RPS
Manual bypass
If in manual bypass, how many out of how many logic are we in?
2 out of 3
RPS
Manual bypass
Used for what?
Mostly maintenance
RPS
Manual Bypass tech spec
The key oiperated channel bypass switch associated with each reactor protection cahannel may be used to lock the reactor trip module in the untripped state as indicated by a light.
Only one channel shall be locked in this untripped state at one time. United operation at rated power shall be permitted to continue with table 3.5-1, column A. only one channel bypass key shall be kept in the CR.
If we took a second key to manual bypass what happens?
Nothing, we can’t energize the trip relay
RPS
Loss of vital bus: failure of a vital bus or channel power supply -> what AND what trip because the UV coil loses power and shunt trip receives DC?
Channel and CRD breaker(s) trip
EOP-001 entry
Any unplanned condition requiring an auto or manual reactor trip requires entry into EOp-001 to manually trip the reactor. IAAT statement?
IAAT conditions exist beyond RPS setpoints and a reactor trip has not occurred, trip the reactor and enter EOP-001
Manual bypass, channel bypass mode for testing -> 2 out of 3 logic. Normally used for which testing?
I & C testing
Only how many channels can be taken to which position at a time?
Only 1 channel to manually bypass at a time
IF one channel is in manual bypass and 2 other channels get valid trip signals, which cabinets and CRD bkrs will do what?
All 4 cabinets and CRD bkrs trip
Rx trip module (RTM) removal: trips channel (even in bypass) trips associated CRD bkr, And…
Forces ALL other channels OUT of bypass condition
RPS
Shutdown Bypass
Break before make connection, meaning the channel will trip when placed in shutdown bypass UNLESS…..
It’s already in manual bypass
RPS
Shutdown Bypass
Auto inserts high RCS pressure trip at what pressure?
1720# into the RPS trip logic
RPS
Anticipatory trip
Set points (2 of them)
FWPs >7%
Turbine trip >45%
RPS
Anticipatory Trip
Basis
Basis is that this event will cause a reactor trip on high pressure, so this feature proactively trips the reactor to prevent challenging the porv/code safeties
SSO reactor trip module
Sub-system light goes BRIGHT on what?
Will NOT go BRIGHT on what?
Goes Bright on any trip string logic tripped
Will NOT go BRIGHT on manual bypass
SSO reactor trip module
BRIGHT RED means what?
Circuit breaker OPEN (52 contact OPEN).
SSO Reactor trip module
Status of 4 channels. Lamp Bright means what?
Relay de-energized, channel tripped
SSO reactor trip module
Manual bypass lamp lit means what?
Means its in manual bypass
RPS
Conditions causing channel trip relay to de-energize: (3 of them)
RPS trip setpoint exceeded
RPS module in TEST without being in manual bypass
Removal of an RPS critical module relay
RPS
Conditions which Trip CRD breaker: (3 of them, sort of…)
Loss of associated vital bus: channel AND bkr trips b/c UV coil loses power
2 out of 4 logic conditions met:
-2 RPS channels tripped opens all 4 CRD bkrs
-2 “simulate trip” switches taken to TRIP in single cabinet opens that CRD bkr
3.) Removal of RX TRIP module (power to UV coil goes through this)
RCP power monitoring system
Purpose
Monitors rcp power consumption statis in lieu of 52 bkr contacts for a theoretical sheared shaft. RPS sees a loss of RCP at what MW (nominal is what MW)
RPS sees a loss of RCP at <2.1 Mwe (nomial is 6 Mwe)
Buffer amplifiers: RPS cabinets have buffer amplifiers which do NOT allow non-safety grade instrumentation to affect safety grade instrumentation due to electromagnetic interference (EMI) non-safety grade instruments get fed through this buffer amplifier before going into RPS cabinet so safety grade instrumentation is NOT affected