ECA-2.1 (depres all S/G's)

Question 1

ECA-2.1

What is the flowrate controlled at if c/d is greater than 100 deg/ any one hour (minimum flow to faulted S/G)?

Why?

Answer 1

25 gpm

• prevent dryout in S/G
  
  • minimize thermal shock if reweted
• minimize further c/d
• minimize inventory in S/G (later in CNMT or ENVMT)

Question 2

ECA-2.1

When checking if RCPs should be stopped in this procedure is there any difference in the RCP trip criteria?

If so why?

Is the basis for stopping the RCPs the same or different than other procedures?

Answer 2

Yes, normal trip criteria

• Prcs < 1300 psig
• at least one ECCS pump injecting

additional criteria

• Subcooling < 20 deg

in this procedure you are very likely to be less than 1300 psig because of huge c/d but you don’t want to secure RCPs unless the RCS is not intact. Thats why you add subcooling criteria

basis is same (dont want to lose RCPs later in casualty and possibly have worse core cooling/ core uncovery)

Question 3

ECA-2.1

What is different about SI termination criteria in this procedure vs. all other procedures?

Answer 3

Normal SI term

• subcooling > 20 deg
• P_rcs stable or rising
• L_pzr > 12 %
• heat sink
  
  • L _s/g > 15% OR
  • F _s/g > 435 gpm

ECA-2.1

• no heat sink criteria (action taken in procedure to intensionally remove heatsink)(25 gpm flow)

Question 4

ECA-2.1

When you are trying to start RCP 2 for spray control, what do you do if RVLIS upper range < 100%?

Why take these actions?

Answer 4

• raise Lpzr > 57%
• raise subcooling > 38 deg
• use Pzr htrs to saturate

pressure transient will be more significant if Pzr is not saturated when RCP is started