RQ-C-4821 (SGTR Analysis & E-3) Flashcards
Given RCS & SG Pressures before and after Reactor Trip and a primary to secondary leak rate (either before or after trip), what relationship can be used to determine the unknown leakrate (either before or after trip).
Qbefore/Qafter = sqrt (dPbefore)/sqrt (dPafter)
What conditions require a transition from E-3 to ECA-3.1 or ECA-3.2
- SGTR w/ a LOCA
- SG that is ruptured AND faulted
- Unable to isolate intact SG from ruptured SG
What are the time critical action time limits in E-3 for initiating the cooldown, initiating RCS Depressurization and for Terminating SI?
- Cooldown 4 min
- Depressurize 3 min
- Terminate SI 2 min
Why is it important that the ruptured SG is isolated from at least one intact SG in E-3
Cooldown and depressurization is dependent on isolating at least one intact SG.
If intact SG is not able to be isolated then when SG is used for cooldown the ruptured SG pressure will lower requiring further RCS depressurization.
What is the primary reason to transition to ECA-3.1 if the ruptured SG pressure is not greater than 450#
The cooldown target temperature would end up being less than the temperature required to avoid an ORANGE path on Integrity which would result in stopping the cooldown
If the ruptured SG pressure is lowering after the cooldown in E-3, why is a cooldown limit of 100 deg F is 60 mins required?
A lower cooldown rate is an attempt to maintain adequate dP (250#). If 250# cannot be maintained further cooldown will not be able to maintain adequate subcooling.
