While in E-2 (Faulted Steam Generator Isolation) what actions are taken if ALL steam generators are faulted
- Go to ECA-2.1 (Uncontrolled Depressurization of ALL SGs)
While in E-2 (Faulted Steam Generator Isolation) what actions are taken if Secondary Radiation levels (SG or SG PORV) are NOT normal
- Go to E-3 (Steam Generator Tube Rupture)
While in E-2 (Faulted Steam Generator Isolation) what actions are taken if subcooling, heat sink, RCS pressure, and Pzr Level are satisfactory
- Go to ES-1.1 (SI Termination)
While in E-2 (Faulted Steam Generator Isolation) what actions are taken if subcooling, heat sink, RCS pressure, and Pzr Level are NOT satisfactory
- Go to E-1 (Loss of Reactor or Secondary Coolant)
While in ECA-2.1 (Uncontrolled Depressurization of All Steam Generators) what actions are taken if Secondary Radiation levels (SG or SG PORV) are NOT normal
- Go to E-3 (Steam Generator Tube Rupture)
While in ECA-2.1 (Uncontrolled Depressurization of All Steam Generators) what actions are taken if RCS pressure is LESS THAN 300#
- Go to E-1 (Loss of Reacotr or Secondary Coolant)
LB LOCA in progress
While in ECA-2.1 (Uncontrolled Depressurization of All Steam Generators) what actions are taken if RWST Level is LESS THAN 30%
- Go to ES-1.3 (Transfer to Cold Leg Recirculation)
While in ECA-2.1 (Uncontrolled Depressurization of All Steam Generators) what actions are taken if RCS pressure is GREATER THAN 300# AND Accumulators DO NOT need to be isolated
- Loop in the procedure until Pressurizer Level is satisfactory THEN reduce ECCS flow
While in ECA-2.1 (Uncontrolled Depressurization of All Steam Generators) what actions are taken once ECCS flow has been reduced and RHR is placed in service for cooldown
- Cooldown the RCS at LESS THAN 100 deg F per 60 minutes until less than 200 deg F
What are the Major Action Categories of E-2 (Faulted Steam Generator Isolation)
- Check Main Steam Isolation
- Check for at least one Non-Faulted SG
- Identify and Isolate Faulted SG
- Check for SGTR
What is the time critical action associated with E-2 (Faulted Steam Generator Isolation)
- Isolate AFW to Faulted SG within 30 minutes of Reactor Trip
For a Steam Line Break upstream of the MSIVs what is the expected plant response
- MSIVs close and depressurization continues
For a Steam Line Break downstream of the MSIVs what is the expected plant response
- MSIVs close and depressurization stops (NO SI)
For a Feedwater break upstream of the FW Isolation check valves what is the expected plant response
- Check valves seat and depressurization stops (NO SI)
For a Feedwater break downstream of the FW Isolation check valves what is the expected plant response
- Check valves seat due to AFW, but depressurization continues
From E-2 (Faulted Steam Generator Isolation) what is the sequence of procedures that will be entered if NO SI is required
- E-0 -> ES-0.1
Since there’s no SI you transition to ES-0.1 after immediate action steps are verified by US
From E-2 (Faulted Steam Generator Isolation) what is the sequence of procedures that will be entered if SI is ACTUATED
- E-0 -> E-2 -> E-1 (if SG isn’t blown down) -> ES-1.1
With no operator action taken, what is the difference in plant response between a small and intermediate/large steam line break
- Small break - MFW maintains SG lvls (NO Rx Trip)
- Large break - Rx Trip will occur after approx. 5 mins
While in E-2 (Faulted Steam Generator Isolation) AFTER RCS temperature stabilizes WHY is AFW periodically reduced
- To maintain SG levels within band due to lowering decay heat levels
What are the important assumptions are made in the UFSAR Steamline break analysis
- Most reactive rod stuck out
- Return to criticality in part of the core
- ECCS injecting through ONE CCP at 2400 ppm will restore subcriticality
During a Steamline break WHY is it important to control AFW flow
- Prevent SG from drying out
- Minimize RCS cooldown
- Prevent SG overfill
- Control RCS temperature after SG blowdown complete
When mitigating a Steamline break, after transition is made to E-1 (Loss of Reactor or Secondary Coolant), if SG pressure is still lowering but attempts have been made to isolate the SG is transition back to E-2 (Faulted SG Isolation) required
- No, the intent of the RNO is satisfied since isolation was attempted in E-2
While in ECA-2.1 (Unctonrolled Depressurization of All Steam Generators) when can transition to E-2 (Faulted Steam Generator Isolation) be made?
- Per the FOP if ANY SG pressure boundary is restored, except while performing SI termination
While in ECA-2.1 (Uncontrolled Depressurization of All Steam Generators) why would you not transition to E-2 (Faulted Steam Generator Isolation) during SI termination or FR-H.1 (Response to Loss of Secondary Heat Sink)
- Because doing so would require introducing AFW to a potentially dried out SG and cause thermal shock
