Reactor Trips Flashcards
Manual reactor trip
1 of 2 switches, operator judgement
Power range, neutron flux
High setpoint 2/4 PR ch >109%RTP (RTP=100%) DNB concern
Low setpoint 2/4 PR ch >25%RTP Startup accident
Can be blocked manually >P-10
PR, neutron flux high positive rate
2/4 PR ch increase >5% of RTP within 2 seconds - Rod ejection
Intermediate range, neutron flux
1 of 2 IR ch >25% of RTP - Startup accident
Can be blocked manually >P-10
SR, neutron flux
1/2 SR ch >1.0E5 cps- startup accident
Can be blocked manually >P-6
Overtemp delta T
2/4 ch >132.5F (+-)penalties- DNB
OPdeltaT
2/4 delta T ch>107.2F (-) penalties- Overpower accident
Pressurizer Pressure-low
2/4 <1885psig (Rate sensitive) DNB
Auto P7 block
Pressurizer pressure high
2/4 Pzr pressure ch >2385 psig- loss of RCS integrity
Reactor coolant flow-low
2/3 rcs flow ch <90% of loop min measure flow (386000 gpm, 96500 gpm/loop),
on 1/4 loops when above P-8 Auto blockP8
on 2/4 loops when between P-7 and P-8 Auto block P7
SGWL Low Low
2/4 NR level ch <18.0% (36.3%) on 1/4 SGs- Loss of heat sink
UV - RCPs
2/4 RCP buses <5268VAC for 0.7 seconds
DNB
Auto P7 block
UF RCPs
2/4 RCP buses <57.0Hz (time delay)- DNB
Auto P7 block
Turbine trip
a. Emergency trip header pressure 2/3 EH P<1000#
b. Turbine throttle valve closure All 4 turbine TVs <1% open
Loss of heat sink
Auto P8 Block
Safety injection input from ESF
Any SI signal- Backup, initiates reactor trip if a rx trip signal not already generated.
