Loss of Neutron Flux

Question 1

What are entry conditions for loss of power range ni channels?

Answer 1

1) Power range indication reading incorrectly
2) RPS Trouble, Unit master in track or FW is RX limited alarms
3) Large neutron error indicated

Question 2

What are major actions for loss of one or more power range ni channels?

Answer 2

1) Perform heat transfer upset section if required
2) Check voltage on failed detector (590 to 600V)
3) If all power range channels failed and no on scale indication then trip Rx and perform RX Trip EOP
4) If 3 or less power range channels failed, reference TS 3.3.1 (RPS) and 3.3.11 (EFIC).
5) Place ICS in auto and bypass applicable RPS channel if desired.
6) Reset power supply if normal voltage not indicated and if returns to normal, reset bistables and remove RPS channel from bypass.

Question 3

What are entry conditions for loss of intermediate range in mode 2?

Answer 3

1) Int range indication reading incorrectly
2) RPS Trouble
3) CRD Withdrawal inhibited alarm

Question 4

What are major actions for loss of intermediate range channels?

Answer 4

1) Trip Rx if no one scale flux indications
2) Check normal voltage (590 to 610V)
3) If both failed, reference TS 3.3.10, if > 2% then perform plant shutdown per 1102.016 (power reduction and plant s/d).
4) If one Int range still operable, continue operation (Only 1 required per TS 3.3.10).
5) If normal voltage not indicated then reset power supplies

Question 5

What constitues no on scale neutron flux indication?

Answer 5

If all of the following apply:

1) 3 of 4 power range = 5%
2) BOTH int range = 10^-10 amps
3) BOTH source range >/= 10^5 cps
4) Wide Range Power indicator (NR-502) inoperable

Question 6

What are entry conditions for loss of intermediate range in mode 2?

Answer 6

Question 7

What are major actions for loss of source range channels in mode 2 - 5?

Answer 7

1) If required due to no on scale neutron flux available, trip RX
2) If both source range fail and both int range = 10^ -10 amps, then refer to TS 3.3.9A (suspend pos rx changes and 3.3.15)
3) If both source range fail and INT range > 10^-10, continue plant operations and refer to 3.3.15
4) If only one source range operable, continue operations and refer to 3.3.15.

Question 8

What actions are required by TS 3.3.9 condition A if both source range channels inoperable (modes 2-5)?

Answer 8

1) Suspend positive RX additions

and

2) Initiate action to insert all control rods immediately

and

3) Open CRD trip breakers in 1 hour

and

4) Verify SDM adequate in 1 hour and every 12 hours after.

Question 9

What actions are required by TS 3.3.10 condition A if both intermediate range channels inoperable (modes 2-5)?

Answer 9

If both INT range fail then

1) Suspend positive rx additions immediately

AND

2) Open CRD breakers in 1 hour

Question 10

What actions are required by TS 3.3.1 for inoperable power range channels?

Answer 10