COLSS: Core Operatng Limit Supervisory System

Question 1

What is the basis for the COLSS DNBR POL?

Answer 1

Assures that the worst AOO wont cause DNBR < 1.34.

Question 2

What is the basis for the COLSS LDP POL?

Answer 2

13.1 kw/ft assures that 2200F Tclad is not exceeded on a LOCA = assures that fuel wont melt.

Question 3

What is used to calibrate the excore NIs?

Answer 3

JSCALOR

Question 4

What is COLSS made up of?

Answer 4

CMC and PC: both run identical programs simultaneously and can drive either meter in the Control Room (CMC is normally connected)

Question 5

How are the inputs divided up between the CMC and the PC?

Answer 5

The same inputs go to both computers

Question 6

What must be done if COLSS is lost?

Answer 6

You have to manually surveil DNBR, LHR, Tilt, and ASI.

Question 7

How does a loss of the PC affect the CMC?

Answer 7

The CMC will no longer receive pulse counts = no CEA sequencing

Question 8

What are the inputs to JSCALOR?

Answer 8

Feed Flow
Feed Temp
Steam Flow
Steam Pressure

Question 9

What are the inputs to NKBDELT?

Answer 9

Tc
Th
Ppzr
RCS Mass Flow Rate:
 - RCP RPM
 - RCP D/P

Question 10

Which inputs in COLSS have redundant sensors that will swap on sensor failure?

Answer 10

RCP RPM
RCP D/P
Pressurizer Pressure
Th
Tc
Steam Flow
(basically everything in the can)

Question 11

How is the Power Limit Margin (Red LED Meter on B05) determined?

Answer 11

Displays the most restrictive of the difference between current Selected Power and DNBR POL, LPD POL, and the License Power Limit. At 100% power, the most restrictive is the License Power Limit (~101.5%).

Question 12

Which inputs in COLSS will not swap on sensor failure?

Answer 12

Feed Flow
Feed Temp
Steam Pressure

Question 13

What COLSS Secondary Power reading gets smoothed to provide JSCALOR?

Answer 13

BSCRAW

Question 14

What is the equation used to determine Secondary Power?

Answer 14

Qsec = m(hstm - hfw) - gains + losses - SGBD

Question 15

How does JSCALOR react if the Blowdown Constant is increased?

Answer 15

JSCALOR reads lower.

Question 16

What is the result of NKBDELT calibrated by JSCALOR?

Answer 16

JCPCAL

Question 17

How does JCPCAL relate with JSCALOR?

Answer 17

JCPCAL is slowly moved toward JSCALOR (1 hr)

Question 18

What is used to calibrate NKBTFST? What results?

Answer 18

JSCALOR

NKCBTFST

Question 19

How does NKCBTFST relate with JSCALOR?

Answer 19

NKCBTFST is slowly moved toward JSCALOR (1 hr)

Question 20

What does it mean if JSCALOR > NKCBTFST?

Answer 20

It means theres a steam leak somewhere

Question 21

What does it mean if JCPCAL and NKCBTFST inputs are bad?

Answer 21

It means COLSS is out of service

Question 22

From what is AZTILT calculated?

Answer 22

Incores

9 calculations at 5 levels

Question 23

What parts of the AZTILT calculation could put COLSS OOS?

Answer 23

< 75% of incore detectors available
< 3 levels available
< 5 calculations

Question 24

What happens if AZTILT > CPC value?

Answer 24

Must change the addressable constant in CPC to be more conservative than the COLSS calculated value.

Question 25

Planar Radial Peaking Factors (Fxy) are computed for _____ levels using CEAs and _____.

Answer 25

20 levels

CEAs and Tc

Question 26

What is the JSCALOR uncertainty?

Answer 26

2%

Question 27

How long does it take to fully reflect a JCSALOR error in Plant Power?

Answer 27

about an hour

Question 28

DNBR POL _________ as ASI gets more negative

Answer 28

lowers

Question 29

How does Tc deviation from 555F affect POLs?

Answer 29

They all decrease (especially LPD)

Question 30

Higher RCP D/P means _______ flow and ________ DNBR POL.

Answer 30

lower

lower

Question 31

If COLSS needs to be restarted, how should this be done?

Answer 31

On one computer at a time

Allow 10-15 minutes for values to stabilize