AP-19 (Malf of Rx MU cntrl)

Question 1

AP-19

What inputs does LT-112 feed into?

What happens if LT-112 fails high?

What happens if LT-112 fails low?

Answer 1

LT-112 outputs

• auto m/u (14% -> 24%)
• charging suct xfr -> RWST (1/2 chnl)
• trip open LCV-112A (87%, also alarm)
• ind (VB 2)

fails high

• LCV-112A opens => Lactual goes down
• no m/u
• empties VCT (no swap to RWST)
• lose CCP’s

fails low

• auto m/u => Lactual goes up
• LCV-112A modulates open (based on LT-114)
• m/u overpowers LCV-112A (100 > 75 gpm)
• VCT goes solid (relieves to LHUT)

Question 2

AP-19

What inputs does LT-114 feed into?

What happens if LT-114 fails high?

What happens if LT-114 fails low?

Answer 2

LT-114 inputs

• modulates open LCV-112A
• CCP suction xfr -> RWST
• indication (VB 2 and HSDP)

Fails high

• LCV-112A modulates open => Lactual goes down
• auto m/u at 14% => Lactual goes up
• when m/u stops @ 24% => Lactual goes down
• L_actual will cycle between 14 and 24%

Fails low

• Low VCT alarm, Lactual will not move
• half channel made up to xfr CCP suction to RWST

Question 3

AP-19

What will give you a m/u deviation alarm?

What happens when you get this alarm to m/u control system?

Answer 3

Boric acid flow >/= 1.5 gpm from flow setpoint for 30 sec

Primary wtr flow >/= 8 gpm from flow setpoint for 30 sec

if m/u controller not in manual FCV’s 110A, B, 111A, B all go closed

Question 4

AP-19

What will LT-112 indicate if a rupture in the reference leg occurs?

What will LT-114 indicate if a rupture in the variable leg occurs?

Answer 4

reference leg break = indicates high

variable leg break = indicates low

level = D/P, => D/P up, Level up

D/P = P_var - P_ref