Permissive interlocks

Question 1

P-4 Reactor trip
What does it do? (5 items)

Answer 1

Setpoint and coincidence
Rx trip breaker and associated bypass breaker not racked in and closed. (RTA and BY A input to trn A SSPS) (RTB and BY B input to trn B SSPS)
Function
1. Actuates turbine trip
2. Actuates FW isolation (Coincident with low Tave)
3. Seals in FW isol from SI or P-14
4. Permit Auto SI block
5. Open main FW pump recircs (in modulate)

Question 2

P-6 Source range

Answer 2

Setpoint and coincidence
1 of 2 IR >1.0E-5% Power
2 of 2 IR<5.0E-6% to clear
Function
Allows manual block of SR high flux trip

Question 3

P-7 At power

Answer 3

Setpoint and coincidence
Power above either the P-10 or the P-13 setpoint (either 1 of the 2)
Power below P-10 AND P-13 to clear 2 of 2
Function
Unblock/block 6 reactor trips
1. 2-loop low of flow
2. PZR low pressure
3.PZR high level
4. RCP breaker open
5. RCP bus UV
6. RCP bus UF

Question 4

P-8 3 loop flow

Answer 4

Setpoint
2 of 4 PR>30%
3 of 4 <30% to clear
Function
Unblock/block 2 reactor trips
1. single loop loss of flow
2. Turbine trip

Question 5

P-10 Nuclear at power

Answer 5

Setpoint and coincidence
2 of 4 PR >10%
3 of 4 PR ch <10% to clear
Function
1. Auto blocks SR high flux trip
2. Permit manual block of IR high flux trip and C1 rod stop
3. Permit manual block of PR high flux, low set point trip
4. Input to P-7 permissive

Question 6

P-11 PZR SI

Answer 6

Setpoint and coincidence
2 of 3 PZR pressure channels <1930 psig (ch455, 456 and 457 only)
SSPS input relays from bistables de-energized >1930 psig
SSPS slave relay to SI 8808s de-energized >1930 psig
Function
1. Permit manual block of PZR and steamline low pressure SIs
2. Permit block of steamline isolation on low steam pressure and enables neg. rate steamline isol P-11
4. Enables following above P-11:
a. PZR pressure low SI
b. Steamline pressure low SI and steamline isol
c. Auto block steamline rate isol

Question 7

P-12 steam dump valve

Answer 7

Setpoint and coincidence
2 of 4 Tave ch<550F
3 of 4 Tave ch >550F to clear
Function
1. Blocks normal steam dump operation. Can be bypassed.

Question 8

P-13 Turbine at power

Answer 8

Setpoint and coincidence
1 of 2 P-impulse ch >10%
2 of 2 P-impulse ch <10% to clear
Function
1. Input to P-7 permissive

Question 9

P-14 SG high-2 level

Answer 9

Setpoint and coincidence
2 of 4 NR ch >88.0% (80.8%) on any 1 of 4 SGs
3 of 4 NR level ch <88.0% (80.8%) on all 4 SGs to clear

Functions:
1. Actuates FW isolation
2. Trips main FW pumps
3. Closes FW 002s
4. Trips main turbine