SPDS (X75)

Question 1

What is the power supply for SPDS?

Answer 1

Vital AC for both units

Question 2

What do the SPDS colors mean?

Answer 2

PCIS
Green - No demand or demand satisfied
Orange – Demand signal present
Red – Demand not met within prescribed time

Measured Parameters
Yellow – potential instrument problem – channel signal out of acceptable range
Red – the measured parameter is above or below a predetermined level
Green – Everything is beautiful

SRVs
Green – SRV is closed/ No Demand
RED – SRV is open. Uses tailpipe pressure switch (85#)

Status Indicator (center of SRVs)
Green – No signal or signal is met
Orange – Demand signal present (>1120 #/ ADS Timer)
Red (ADS Only) – ADS valve(s) failed to open

Keys
Orange whenever the valve’s isolation function has been overridden

Question 3

What do the SCRAM messages/colors mean on SPDS?

Answer 3

Orange – for up to 10 seconds

Red – after 10 seconds if All Rods Not (WILL DISPLAY RED SCRAM if rods at 02, even tho Rx still S/D)

All Rods In – Replaces the message “Scram” when all rods are in. Does not count 02 position. Only counts reed switch 00, 51, 52

Question 4

What does “Hot Legs May Boil” mean on SPDS?

Answer 4

DW temp near RWL reference legs temps are within 10F of RPV saturation temp

Question 5

What does “May Miss Trip” mean on SPDS?

Answer 5

Actual RWL (corrected) is below the lower tap before uncorrected level has reached -101” level.

Pointing out a variance in corrected v uncorrected.

Question 6

What is the difference for PCIS “Part” and “All” on SPDS?

Answer 6

Part indicates isolation has not fully completed.

All indicates the isolation is complete.

Orange means demand, Green means isolation happened within the preprogrammed time, Red means isolation did not occur within the preprogrammed time.