Core Flood

Question 1

List the acceptance criteria for ECCS.

Answer 1

Hydrogen <= 1%
Oxidation of cladding <=17%
Temperature of cladding <=2200F
Cool-able geometry
Keep cool (Long Term)

Question 2

Why do we call Core Flood a passive system?

Answer 2

No outside power is required
No outside actuation signal is required
Nitrogen pressure provides the driving force

Question 3

What is required for ONE train of ECCS?

Answer 3

ONE train of HPI
ONE train of LPI
BOTH CFTs

Question 4

What are the 3 phases of a LOCA?

Answer 4

1. ) Blowdown- rapid loss of coolant
2. ) Refill- both CFT discharge
3. ) Reflood- HPI & LPI injection

Question 5

What is the Function of CFT System?

Answer 5

Core Protection after intermediate to large breaks
Passive injection when RCS <600#
Both tanks cover 3/4 of core

Question 6

What is the required CFT boron concentration?

Answer 6

2270-3500 ppm

Question 7

List ECCS Acceptance Criteria

Answer 7

• Peak clad temp. <= 2200 deg F
  
  • Clad oxidation <= 17% of clad thickness
  • Max H2 generation <= 1% of all that could be generated
  • Maintain coolable core geometry
  • Provide long-term cooling

Question 8

Core Flood Tank Tech Specs with 1 hr Conditions

Answer 8

Two CFTs operable
Modes 1 & 2, Mode 3 with RCS press >800psig

Condition: 1 CFT inop for reasons other than boron
Action: Restore to operable status
Completion Time: 1 hour

• Level: 12.6 to 13.4 feet
• Pressure: 560 to 640 psig
• MOV Discharge Valve de-energized open (TRM) One of Two pressure and One of Two level instrument channels per CFT

Question 9

Basis for pressure and level limits.

Answer 9

640# = sufficient volume to refill
560# = sufficient pressure to fully inject in time

13. 4’ = enough N2 to fully inject contents
14. 6’ = sufficient volume to refill

Question 10

Horn and lights if CFT MOV closed and RCS press >____psig

Answer 10

750psig

Question 11

In normal ops, MOVs opened when raising RCS press @ _______ psig.

Answer 11

700-730 psig

Question 12

In normal ops, CFT MOVs required to be open prior to ____ psig RCS press.

Answer 12

800 psig

Question 13

In normal ops, CFT MOVs required to be closed prior to ____ psig RCS press.

Answer 13

700 psig

Question 14

Describe interlocks between CFT outlet valves and DH valves.

Which CFT to which DH valve?

Answer 14

A CFT interlocked with CV-1050 and B CFT interlocked with CV-1410

Question 15

Decay heat iso valve will _____ if CFT outlet valve is removed from 100% _____ seat.

Answer 15

Close, closed