3.1 Reactivity Control Systems

Question 1

3.1.1 SDM - RTBs open

LCO 3.1.1 SDM shall be greater than the value in the COLR

Applicability: MODES 3, 4, and 5 with RTBs open

Answer 1

SDM not within limit: Initiate boration to restore SDM within 15 minutes

To meet this, borate > 26 gpm from a 4000 ppmB source (RWT) within 15 minutes

Question 2

What is the definition of Shutdown Margin (SDM)?

Answer 2

Instantaneous amount of reactivity that the reactor is subcritical (or would be subcritical) if all FSCEAs are gully inserted into the core, with the exception of the CEA of highest worth.

Question 3

3.1.2 SDM RTBs Closed

LCO 3.1.2 Reactivity controlled by:
A. SDM > value in COLR
B. Kn-1 < 0.99 when Tc < 500F
C. Criticality not achieved with a shutdown group

Applicability: Modes 3, 4, and 5 with RTBs closed

Answer 3

A. SDM not within limit: borate within 15 minutes
B. Kn-1 not within limit when Tc < 500F. Vary CEAs. 15 minutes
OR. AND
Criticality achieved with a shutdown group : Borate. 15 minutes

Question 4

3.1.5 CEA Alignment

LCO 3.1.5 All FS CEAs shall be Operable
AND
Aligned within 6.6 inches of its Group

Applicability: Modes 1 and 2

Condition A

Answer 4

Operable means moveable and trippable with a less than 4 second drop time.

A. One or more CEA misaligned >6.6” but < 9.9” Reduce power within 1 hour
OR. AND
One CEA misaligned > 9.9”. Restore alignment within 2 hours

Question 5

3.1.5 CEA Alignment

LCO 3.1.5 All FS CEAs shall be Operable
AND
Aligned within 6.6 inches of its Group

Applicability: Modes 1 and 2

Condition B

Answer 5

B. One CEA rod position indicator operable. Restore bad one to operable within 6 hours
OR
Verify CEA group is fully out or fully in within 6 hours, then once per
12 hours.

Question 6

3.1.5 CEA Alignment

LCO 3.1.5 All FS CEAs shall be Operable
AND
Aligned within 6.6 inches of its Group

Applicability: Modes 1 and 2

Condition C

Answer 6

C. One or more FS CEAs inoperable. Be in Mode 3 within 6 hours

Operable means trippable

Question 7

3.1.5 CEA Alignment

LCO 3.1.5 All FS CEAs shall be Operable
AND
Aligned within 6.6 inches of its Group

Applicability: Modes 1 and 2

Condition D

Answer 7

D. Two or more CEAs misaligned by > 9.9”. Trip the reactor IMMEDIATELY

Question 8

3.1.6 Shutdown CEAs

LCO 3.1.6 All Shutdown CEAs withdrawn > 147.75”

Applicability: Mode 1, and 2 with any Regulating CEA not fully inserted.

Answer 8

A. One SD CEA not > 147.75”. Restore within 2 hours

Question 9

3.1.7 Regulating CEA Insertion Limits

LCO 3.1.7 The PDIL circuit shall be Operable, and with the COLSS in service. If COLSS is out of service the CEAs shall be limited to the withdrawal sequence and insertion limits from the COLR.

Applicability: Modes 1 and 2

NOTE: Not applicable for up to 2 hours following a RPCB

Condition A

Answer 9

A. Reg groups inserted beyond TIL with or without COLSS. Restore CEAs OR Reduce Power within 2 hours