Excore (NI)

Question 1

What are the power supplies for the Start-up Channels?

Answer 1

NNN-D11 and NNN-D12 (120Vac)

Question 2

What kind of detector is used in the Start-up Channels?

Answer 2

BF3 proportional counters (located mid-plane of the core)

Question 3

What are the power supplies for the Safety Channels?

Answer 3

PNA-D25 Channel
PNB-D26
PNC-D27 Channel
PND-D28

Question 4

What power ranges are the Safety Channels rated for?

Answer 4

2E-8% to 200% power

Question 5

What is the plant response to a loss of the top fission detector in a Safety Channel?

Answer 5

Trips and pre-trips on DNBR and LPD. That channel read 67% power (log power unaffected). Enter LCO 3.3.1 for that channel.

Question 6

What is the plant response to a loss of the middle fission detector in a Safety Channel?

Answer 6

Trips and pre-trips on DNBR and LPD. That channel read 67% power (log power reads zero).

Question 7

What kind of detector is used in the Safety Channels?

Answer 7

Fission chamber coated with enriched U-235

Question 8

What bistables are associated with the Safety Channel logarithmic circuits?

Answer 8

Log 1 bistable (> 10-4%): provides a permissive to permit bypass of the high log power trip.
o Bypass is automatically removed when power lowers below the bistable.
o Alarm LIT until bypassed (Hi Log Pwr Lvl Byp Perm)
Log 2 bistable (≤10-4%): provides a permissive to permit bypass the DNBR and LPD trips (CPC trips).
o Bypass is automatically removed when power rises above the bistable.
o Conservatively set to 10-5% during initial startup

Question 9

What is the power supply for the Control Channels?

Answer 9

NNN-D11/D12

Question 10

How would a Control channel respond to a loss of the top detector?

Answer 10

Channel fails to 1/2 (50%)

Question 11

What action is taken when Startup channel counts reach 10,000 during a Reactor Startup?

Answer 11

Startup channels are turned off by selecting the Control channel on B04 and pushing the HV PERMIT pushbotton