Interlocks and Permissive Flashcards
TRA00144
What provides power to the permissive bus?
670-E-73 from E-15.
Impact of opening permissive bus breaker during operation.
Reverse.
Location and supply for 24V interface relay ABT?
Located by door to RDAS room from RCR
IP2 and E-183 are power sources
Why is rod withdrawal inhibited if power is lost to one quadrant?
Operator must be able to insert all rods before ANY withdrawal is allowed.
What function to console displays of rod interlocks provide?
Display of current state and aids in troubleshooting rod control issues.
What is the function of the Reactor On and Startup Alarm Bypass Test Block?
allows shutdown testing of the key switch functions without sounding startup horn or lighting the reactor on signs.
How many rods can be withdrawn during reactor shutdown using test blocks and how does the system provide this function?
One of each kind (except SR which all can be withdrawn), one at a time.
What will happen if the reactor on keyswitch is turned to OFF during normal reactor operation?
Reactor reverse will occur due to loss of the START relay.
What is the purpose of the startup test block?
Turns off horn and reactor on light for rod testing during shutdown.
What is the purpose of the shutdown test blocks for individual rod groups?
bypasses relays to allow withdrawal for testing during reactor shutdown while also providing interlocks to prevent excessive rod withdrawal.
What is the power supply to the permissive bus?
E-73 from E-15 diesel/comm
How do we ensure inward rod motion always overrides outward motion?
In over out - outward movement always blocked by inward movement.
A loss of diesel/comm E-15 has just occurred. What will happen to control rods?
Loss of permissive bus power, reverse actuated but rods have no power for 60 seconds at which point E-80 transfers to utility UPS and the OSCCs and NSRs are inserted. Nothing automatically happens to the SRs.
Which SR interlocks are bypassed by a LogN channel being >10-5 Nf?
LCRM on scale, NSR/OSCC at inner/lower limits, SU timer interlocks
How long does it take to withdraw SRs on the timer?
4 minutes in normal speed, 20 minutes in timer mode.
How do we meet the SRs at lower limit interlock when w/d the SRs?
There is a latching relay that will stay latched until the permissive bus is de-energized
Which interlocks must be met to withdraw the reg rods?
No fission chamber motion, reverse cleared, start relay energized. All SRs at the upper limit or neck shim shut down test block removed.
Which interlocks must be met to withdraw neck shim rods?
No RR in manual motion, reactor period 30 sec, timer, sr w/d no reverse, no insert, voltage available to insert bus, no fission chamber motion.
When can we withdraw the neck shim rods in GROUP?
Both Log-Ns must be <10-5 and the withdraw interlock tree must be met.
How many fission chambers can be withdrawn at the same time?
Only one at a time.
What is the power supply for the fission chamber drive motors?
R1 from E-73 from E-15
Which interlocks are required to place the RR in AUTO?
RR at >42 inches and Reactor in run
Which interlocks are required to place the reactor in RUN?
Fission chamber at outer limit and power <10-3 Nf
Which interlocks are associated with reactor period?
30 sec (bypassable, non in run), 15 sec (not bypassable) - lose w/d permit, 5 second - REVERSE
How is a scram from PPS system recognized by the reactor interlock system?
Opto isolators in the RCCC circuits sense a change in RCCC current and are sent to E350 and then RC5 where RS relays are de-energized
What can give you a reverse?
Reverse timers (25 mins after scram if all safety rods are not fully withdrawn to their upper limit), xy bus undervolt, 5 sec period, rx not in start
What is the function of the EBR switches and how do they achieve this?
Scram rx and give a reverse, used for evacuation - reverse drops the 27 MA and MB relays, scram kills power to the RCCCs.
What can give you a slow setback?
Exp loops (if >3NL), quad water power, neutron level, PCS Tin
