TS 3.3.4 RPS Logic and Trip Initiation

Question 1

LCO 3.3.4 ___ channels of RPS Matrix Logic, ___ channels of RPS Initiation Logic, ___ channels of RTCBs, and ___ channels of Manual Trip shall be OPERABLE.

APPLICABILITY: ___

Answer 1

6 of RPS Matrix Logic

4 channels of all the others

APPLICABILITY: MODES 1 and 2,
MODES 3, 4, and 5, with any RTCBs closed and any CEA capable of being withdrawn

Question 2

During AOOs, which are those events expected to occur one or more times during the plant life, the acceptable limits are:
___
___
___

Answer 2

1. DNBR shall be maintained above the Safety Limit value to prevent departure from nucleate boiling
2. Fuel centerline melting shall not occur; and
3. The RCS pressure SL of 2750 psia shall not be exceeded.

Question 3

Each RTCB is operated by either ___, ___ or ___

Answer 3

Manual Trip push button
Supplementary Protection System trip relay
RPS actuated initiation relay

Question 4

LCO 3.3.4 on the RPS Logic channels ensures that each of the following requirements are met:
___
___
___

Answer 4

1. A RX Trip will be initiated when necessary
2. The required protection system coincidence logic is maintained (minimum 2 out of 3, normal 2 out of 4); and
3. Sufficient redundancy is maintained to permit a channel to be OOS for testing or maintenance

Question 5

A matrix logic is considered inoperable if ___

Answer 5

…if a coincident trip in the same function in the 2 OPERABLE channels monitored by the Logic Matrix will not remove power from the coils of all 4 matrix relays.

• OPERABILITY of the Matrix Logic isn’t affected by bypassed or inoperable measurement channels

Question 6

Loss of a single vital bus will de-energize 1 of 2 power supplies in each of 3 matrices. This will result in ___

Answer 6

2 RTCBs opening; however, the remaining 2 closed RTCBs will prevent a RX Trip

Question 7

An Initiation Logic is considered inoperable if ___

Answer 7

…the contacts on the initiation relay will not operated when power is removed from the coils of ANY of the 6 matrix relays in the trip paths.

Question 8

If 1 RTCB has been opened in response to a single RTCB channel, Initiation Logic channel, or Manual Trip channel failure, the affected RTCB may be closed for up to ___

Answer 8

…1 hour for Surveillance on the OPERABLE Initiation Logic, RTCB, and Manual Trip channels.

Question 9

If a single matrix power supply or vital bus failure has opened 2 RTCBs, Manual Trip and RTCB testing on the closed breakers ___

Answer 9

…CANNOT be performed without causing a trip.

Question 10

Manual Trip push buttons are also provided at the RX Trip switchgear (locally) in case the CR push buttons become inoperable or the CR becomes uninhabitable. These are ___

Answer 10

…not part of the RPS and cannot be credited in fulfilling LCO OPERABILITY requirement. Furthermore, LCO actions need not be entered due to failure of local Manual Trip.

Question 11

LCO 3.3.4 CONDITION
A. One Matrix Logic inoperable OR

3 Matrix Logic channels inoperable due to a common power source failure de-energizing 3 matrix power supplies

Answer 11

A.1 Restore channel to OPERABLE status (48 Hours)

Question 12

LCO 3.3.4 CONDITION
B. 1 channel of Manual Trip, RTCB, or Initiation Logic inoperable in MODE 1 or 2

NOTE: RTCBs associated with 1 inoperable channel may be closed for up to 1 hour for the performance of an RPS CHANNEL FUNCTIONAL TEST

Answer 12

B.1 Open the affected RTCB (1 Hour) OR

B.2.1 Open the redundant RTCB in the affected Trip Leg (1 Hour) AND
B2.2 Open the affected RTCB (48 Hours)

Question 13

Required actions B.2.1 and B.2.2 provide for opening 1 of the redundant RTCB in the affected Trip leg within 1 hour and opening the affected RTCB within 48 hours. These actions allow a RTCB that fails to open to ___

Answer 13

…remain undisturbed for 48 hours for FAILURE ANALYSIS

Question 14

LCO 3.3.4 CONDITION
C. 1 Channel of Manual Trip, RTCB, or Initiation Logic inoperable in MODE 3, 4 or 5

*Same Note as Condition B

Answer 14

C.1 Open the affected RTCB (48 Hours)

Question 15

LCO 3.3.4 CONDITION

D. 2 channels of RTCBs, Manual Trip or Initiation Logic affecting the same trip leg inoperable.

Answer 15

D.1 Open the affected RTCBs (Immediately)

Question 16

With both (Initiation Logic channels) failed in a non-trip condition, the reactor will ___

Answer 16

…NOT trip automatically when required.

• Affected RTCBs must be opened immediately by using the appropriate Manual Trip push buttons

Question 17

LCO 3.3.4 CONDITION
E. Required Action and associated Completion Time of Condition A, B, or D not met. OR

1 or more Functions with more than one Manual Trip, Matrix Logic, Initiation Logic, or RTCB channel inoperable for reasons other than Condition A or D

Answer 17

E.1 Be in MODE 3 (6 hours) AND

E.2 Open all RTCBs (6 hours)