ML13150A181
| ML13150A181 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 11/19/2013 |
| From: | Pacific Gas & Electric Co |
| To: | Office of Nuclear Reactor Regulation |
| Warren Lyon | |
| References | |
| Download: ML13150A181 (8) | |
Text
Trade Trade--Off Between Tank Off Between Tank Vortexing Vortexing M
i M
ti Margin Margin and ECCS and ECCS Function Function Volume Control Tank Volume Control Tank Volume Control Tank Volume Control Tank Refueling Water Tank Refueling Water Tank g
Containment Recirculation Sump Containment Recirculation Sump NRC Meeting On Vortexing April 18 2013 Anderson Lin Diablo Canyon Power Plant April 18, 2013 Diablo Canyon Power Plant (805) 545-4286 Axle@pge.com
Transfer From VCT to RWST Transfer From VCT to RWST Transfer From VCT to RWST Transfer From VCT to RWST Upon S signal CCP suctions are aligned to Upon S signal CCP suctions are aligned to Upon S signal, CCP suctions are aligned to Upon S signal, CCP suctions are aligned to the RWST the RWST RWST water level is at the highest to RWST water level is at the highest to RWST water level is at the highest to RWST water level is at the highest to compress any entrained gas from the VCT compress any entrained gas from the VCT CCPs are boosted by the RWST static head CCPs are boosted by the RWST static head CCPs are boosted by the RWST static head CCPs are boosted by the RWST static head CCPs are multi CCPs are multi--stage pumps tolerate void well stage pumps tolerate void well (recent tests and Roadmap Report)
(recent tests and Roadmap Report)
(recent tests and Roadmap Report)
(recent tests and Roadmap Report)
If VCT level were increased to prevent any If VCT level were increased to prevent any vortex less VCT volume available for charging vortex less VCT volume available for charging vortex, less VCT volume available for charging vortex, less VCT volume available for charging
& letdown inventory control and H2 control
& letdown inventory control and H2 control
Transfer From the RWST to Sump Transfer From the RWST to Sump Transfer From the RWST to Sump Transfer From the RWST to Sump
Transfer From the RWST to Sump Transfer From the RWST to Sump Transfer From the RWST to Sump Transfer From the RWST to Sump For a 40 diameter RWST its it is For a 40 diameter RWST its it is For a 40 diameter RWST, its it is For a 40 diameter RWST, its it is
~9,400 gal/ft.
~9,400 gal/ft.
A conservative 9 requirement to A conservative 9 requirement to prevent vortexing quarantines prevent vortexing quarantines 84,000 84,000 p
g q p
g q gallon of RWST inventory gallon of RWST inventory
Transfer From the RWST to Sump Transfer From the RWST to Sump Transfer From the RWST to Sump Transfer From the RWST to Sump RWST inventory is relied upon for core RWST inventory is relied upon for core RWST inventory is relied upon for core RWST inventory is relied upon for core cooling and containment cooling and containment depressurization depressurization depressurization depressurization If too much RWST inventory was If too much RWST inventory was reserved to prevent vortexing reserved to prevent vortexing reserved to prevent vortexing, reserved to prevent vortexing, EOP setpoint revision EOP setpoint revision Reduce credited core delta BTU transfer Reduce credited core delta BTU transfer Increase containment post LOCA P / T Increase containment post LOCA P / T
Transfer From the RWST to Sump Transfer From the RWST to Sump Transfer From the RWST to Sump Transfer From the RWST to Sump RWST inventory is credited to submerge RWST inventory is credited to submerge sump screens sump screens Without submerge the sump screens, Without submerge the sump screens, Without submerge the sump screens, Without submerge the sump screens, screen performance would change from screen performance would change from pipe flow to channel flow pipe flow to channel flow pipe flow to channel flow pipe flow to channel flow Flowrate through the screen relies on Flowrate through the screen relies on t
l l d i
id th t
l l d i
id th water level drops inside the screen water level drops inside the screen Lowered the water level inside the sump Lowered the water level inside the sump screen creates even worse vortexing screen creates even worse vortexing concerns to pump suctions concerns to pump suctions
Transfer From the RWST to Sump Transfer From the RWST to Sump Transfer From the RWST to Sump Transfer From the RWST to Sump RWST inventory to deliver boron for RWST inventory to deliver boron for RWST inventory to deliver boron for RWST inventory to deliver boron for sump pH control sump pH control b
d b
d Sump pH must be maintained 8.0 Sump pH must be maintained 8.0 - 9.5 9.5 Too much RWST inventory quarantined in Too much RWST inventory quarantined in the RWST could result in higher pH the RWST could result in higher pH Post LOCA equipment qualification may Post LOCA equipment qualification may Post LOCA equipment qualification may Post LOCA equipment qualification may need to be revised need to be revised
What Would Be A Reasonable What Would Be A Reasonable Permissible Air Ingestion Permissible Air Ingestion No Void At All ?
No Void At All ?
No Void At All ?
No Void At All ?
Minimal Sporadic Ingestion ?
Minimal Sporadic Ingestion ?
Minimal Sporadic Ingestion ?
Minimal Sporadic Ingestion ?
2% ?
2% ?
3% ?
3% ?
Continuous 1% ?
Continuous 1% ?
What is the reasonable air ingestion ?
What is the reasonable air ingestion ?