OPRM

Question 1

What power:flow combination is OPRM designed to monitor?

Answer 1

Power >25% and flow <60%

Question 2

What thermal limit is the OPRM system designed to protect?

Answer 2

MCPR - prevent onset of transition boiling

Question 3

What does OPRM do when valid oscillations are detected?

Answer 3

When a valid indication of flux oscillations is sensed, the OPRM generates an RPS 1/2 SCRAM. A full RPS SCRAM would occur if another 1/2 SCRAM exists concurrently in the opposite RPS division (both OPRMs sensing valid oscillations conncurrently).

Question 4

How many LPRMs are contained in an OPRM cell?

Answer 4

4

Question 5

How many LPRM signals does an OPRM monitor?

Answer 5

20/21 from it’s own and 20/21 from it’s companion 40-42 total

Question 6

What causes Thermal-hydraulic Oscillations?

Answer 6

Trip of RR Pump
Loss of FW Heating
Poison Burnout
Recirc Pump Controller Failure
Control Rod Withdrawal

Question 7

What are indications of Core Oscillations?

Answer 7

Increase of oscillations to 5-6% w/ frequency of 1.5-3.5sec (or .3-.7Hz)
Sharp Positive and Neg swings on SRM period Meter
LPRM/APRM high and downscale alarms cycle 1.5 to 3.5sec

Question 8

What does OPRM receive input from?

Answer 8

LPRM
APRM
Companion OPRM
“TWO MODULES TO EACH OPRM CHANNEL

Question 9

What does the OPRM Bypass Switch do?

Answer 9

Allows ONE OPRM to be bypassed per RPS division

Question 10

What are the Master/Slave OPRMS

Answer 10

Master: 1, 2, 4, 5
Slave: 3, 7, 6, 8

Question 11

What are the Trips for OPRM? what is their result?

Answer 11

Period
Amplitude
Growth Rate
SCRAM HALF SIGNAL

Question 12

What is the Period TRIP?

Answer 12

Only algorithm credited in safety analysis and needed for operability
Minimum number of oscillation counts have occurred and experienced AT LEAST a minimum increase in amplitude:
15 confirmed counts with growth rate >1.13

Question 13

What is the Amplitude based Trip?

Answer 13

Amplitude of 2 consecutive peaks exceed specified values

Question 14

What is the Growth Rate Trip?

Answer 14

First Peak exceeds specified min value and second peak exceeds calculated value. - 2 confirmed counts with growth rate of >1.3

Question 15

How many cells are in the OPRM system?

Answer 15

128 - each with 4 LPRMs

2 modules per channel (1/3,2/7,4/6,5/8)

Question 16

How many modules per OPRM channel are required to be OPERABLE?

Answer 16

As long as EITHER can trip, channel is OPERABLE

Question 17

What happens if OPRM is in TEST?

Answer 17

Disable output HI alarms and TRIP -freezes 20 minute buffer
Allows downlaoding event buffer and will cause Trouble/INOP alarm
CAN BYPASS 1 OPRM per division

Question 18

What indications are in the MCR and where are they?

Answer 18

White LIght on 5 panel - bypass
Green light on 5 panel - OPRM enabled
IF THERE ARE INDICATIONS OF OSCILLATIONS - SCRAM IMMEDIATELY
ANY LPRM OR APRM - noise level reaches grater than 2 times initial level w/ 1.5 to 3.5 sec. period

Question 19

What is the power supply for OPRM?

Answer 19

Module 1, 2, 3, 7 - RPS A

Module 4,5,6,8 - RPS B