ML15236A134

Presentation Slides for Public Meeting with Arizona Public Service Generic Letter 2004-02 for Palo Verde Nuclear Generating Station, Units 1, 2, and 3 (TAC Nos. MC4702, MC4703, and MC4704)

ML15236A134
Person / Time
Site:	Palo Verde
Issue date:	08/26/2015
From:	Watford M M Plant Licensing Branch IV
To:	Edington R K Arizona Public Service Co
Watford M M
References
TAC MC4702, TAC MC4703, TAC4704
Download: ML15236A134 (11)

Text

Palo Verde Nuclear Generating StationGeneric Letter 2004-02August 26th, 2015 IntroductionsTom WeberDepartment LeaderNuclear Regulatory Affairs

Background

• 12/18/2013 -APS submitted Revision 2 to Supplemental Response to NRC Generic Letter 2004-02*4/15/2015 -PVAR 4644513 documents that APS failed to identify and evaluate Microtherm on the Reactor Vessel*6/10/2015 -Initial Public Meeting with NRC-Beaver Valley Operating Experience with Microtherm-Communication with the Industry-Industry Testing of Microporous Insulation-Extent of Condition3 Microtherm Locations4 Break LocationsLimiting Break Location Steam Generator Hot Leg NozzleReactor Pressure Vessel (RPV) Nozzle break locations5 Extent of ConditionRed: Temp-Mat Impacting Existing Break Location(SG HL Nozzle)6Green: Temp-Mat Impacting New RPV Break LocationLOCATIONUnit 1Unit 2Unit 3Cold Leg 1A, 1B, 2A, 2B RTDXXXBelow RPV NozzleXXXRPV CavityXXXRPV ICIsXXXCrossover 1A, 1B, 2A, 2B RCP NozzleXCrossover 1A, 1B, 2A, 2B SG NozzleXCold Leg 1A, 1B, 2A, 2B RPV ElbowXUnit 3 Only Analysis to date*Debris Generation-Primary success path is removal of Temp-Mat in the D-rings for current limiting break-Microtherm ZOI (zone of influence) based on robustness of encapsulation-Encapsulated Microtherm ZOI and restrained separation of pipe at RPV nozzle break limits Microtherm quantity to the local region of the break location*Debris Transport-RPV nozzle break -Temp-Mat generated to the Reactor Cavity will not transport to strainers based on very low flow velocity and upward vertical flow path of 18 to 23 feet*Cold Leg RPV Elbow Temp-Mat is still being analyzed for impact (Unit 3 Only)-Generated Microtherm assumed to transport to the strainers7 Analysis to date (cont)*Industry Testing / NPSH-Salem U2 Test 6 Head Loss conditions (with Min-K) bound Palo Verde with Microtherm for post-LOCA flow scenarios-Comparative analysis indicates Palo Verde NPSH and structural limits should be bounded by existing SG HL Break location8 Actions to finalize*Confirm Removal of Temp-Mat from D-ring*Confirm Removal of Temp-Mat from Unit 3 RPV Cold Leg Elbows*Confirm impact of identified Temp-Mat and Microtherm for RPV on chemical effects*Finalize LPSI pump failure to trip after Recirculation Actuation Signal (RAS)

Scenario*Complete final review of assessment report9 Summary*A resolution path exists for D-ring and RPV nozzle break cases-Confirmation of chemical effects and LPSI flow scenario items in process-Open Strainer Area is expected to be comparable with original analysis*Confirm removal of Temp-Mat in D-Ring-Removal of RTD Temp-Mat (all 3 units)-Removal of Crossover Piping Temp-Mat in Unit 3*Confirm removal of Cold Leg RPV Elbows in Unit 3 *Supplement APS Response to GL 2004-0210 11We SAFELYand efficientlygenerate electricity for the long term