RPS Flashcards by Unknown Unknown

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

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RPS
Purpose

Protects
Reactor core against fuel cladding failure

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RPS Trip Scheme:
RC pressure low
basis

RCS pressure <1900#
Prevents flue clad damage (min DNBR)

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RPS Trip Scheme:
Flux/delta flux/flow

Power> 1.08x % RC flow-imbalance

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RPS Trip Scheme:
Power/pumps

> 55% pwr w/ 1 RCP per loop,

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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)

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RPS Trip Scheme:
Power/pumps

> 0% power loss of both RCPs

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RPS trip scheme:
High power

RX >105.1%

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RPS trip scheme:
RCS pressure high

RCS pressure >2355#

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RPS trip scheme:
RC temp HIGH

RC temp > 618.8F

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RPS trip scheme:
Reactor bldg. high

RB pressure > 4#

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RPS trip scheme:
Anticipatory Rx trips

<75# FWP lube oil (95# reset)

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RPS trip scheme:
Anticipatory RX trips

<4EH00# EHC pressure (500# reset)

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RPS electronic trip signal is sent if:

Manual pushbutton on CC depressed
Both safety grade wide range RCS pressure transmitters >2500 psig

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RPS
Energize or de energize to trip?
When relay on CRD supply bkrs?

De-energize to trip
UV relay on CRD supply bkrs

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DSS
Energize or de-energize
How to trip?

De-energize to trip
61 gate drives

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What system provides ATWS protection?

DSS

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What is the basic RPS trip logic?

2 out of 4

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What is diverse about DSS?

Energize to actuate, different signals, acts on 61 gate drivers

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How does DSS actuate?

Energize to tells gate drivers to remove power to the SRPS

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RPS de-energizes undervoltage coils of the CRD bkrs

Yes that’s true

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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

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How does this system work with malfunction? If A and B CRD don’t work, did we trip the reactor?

Yes

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DSS
Setpoints
(2 of them)

Manual DSS pushbutton (always press when we trip)
2 out of 2 RCS pressure >2500 psig

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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