05000338/FIN-2015008-02
From kanterella
Jump to navigation
Jump to search
Finding | |
|---|---|
| Title | ECST Level Indication/Setpoints and Associated Operator Action that Ensures the Auxiliary Feedwater Pumps have an Adequate Suction Source |
| Description | The inspectors identified an Unresolved Item (URI) associated with the emergency condensate storage tank (ECST) level indication/setpoints and associated operator actions that ensures the auxiliary feedwater (AFW) pumps have an adequate suction source. UFSAR, Section 7.4-2, states that the emergency condensate storage tank (ECST) was designed to supply the initial eight hours of water to the auxiliary feedwater (AFW) pumps during licensing bases events. The inspectors noted that the licensee utilized operator actions to reduce AFW flow during the initial stages of events which is typically accomplished in order to prevent over cooling of the primary RCS during events where maximum AFW is not required. For events where maximum AFW may be required, the licensee developed calculations to ensure that an adequate water supply was maintained. The licensees Calculation ME-0584, Maximum AFW Pump Flow and NPSH Analysis, (dated 11/04/1999) determined that AFW flow reduction was required within the initial 30 minutes of an event to ensure that the pumps had sufficient net positive suction head. The inspectors determined, in some cases, that operator actions would be required prior to the receipt of the ECST tank level alarm that was described UFSAR Section 10.4.3.3, which stated that the ECST had redundant ECST safety-level alarms (1/2-CN-LI-200A and -200B) to alert operators that sufficient inventory remained for 20 minutes of pump operation at the highest-volume flow rates. Additionally, the inspectors noted that a Virginia Electric Power Company letter, dated December 22, 1999, stated that Technical Specifications ensure that the level maintained in the ECST is adequate to mitigate the accident without operator action during a design basis accident. Therefore, the indication of ECST level is not required as a Type A variable. Indication of ECST level remains a Type D, Category 1 variable... This issue is unresolved pending the NRCs review of applicable licensing requirements, calculations, and operating procedures to assess the adequacy of the ECST level indication/setpoints and associated operator actions to ensure that the AFW pumps have an adequate suction source as described by their licensing design basis. This issue is identified as URI 05000338 & 05000339/2015008-02, ECST Level Indication/Setpoints and Associated Operator Action that Ensures the Auxiliary Feedwater Pumps have an Adequate Suction Source. |
| Site: | North Anna  |
|---|---|
| Report | IR 05000338/2015008 Section 4OA5 |
| Date counted | Dec 31, 2015 (2015Q4) |
| Type: | URI: |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | |
| Inspectors (proximate) | D Jones J Dymek M Thomas S Shaeffer W Monka Mastersd Lanyi G Croon G Eatmon |
| INPO aspect | |
| ' | |
Finding - North Anna - IR 05000338/2015008 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Finding List (North Anna) @ 2015Q4
Self-Identified List (North Anna)
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||