ML13218A021

Licensee Slides, 08/07/13 Preapplication Meeting with Wolf Creek Nuclear Operating Corporation to Discuss Long-Term Corrective Actions for Water Hammer Events in the Essential Service Water System at Wolf Creek

ML13218A021
Person / Time
Site:	Wolf Creek
Issue date:	08/07/2013
From:	Wolf Creek
To:	Office of Nuclear Reactor Regulation
Lyon C
References
TAC MF2457
Download: ML13218A021 (13)

Text

1 Modification to Essential Service Water System August 7, 2013 WCNOC-NRC Pre-submittal Meeting 2 Meeting Agenda*Introduction of the team*State the objectives of the meeting*Describe the waterhammer phenomena*Explain how this modification will address the issue*Describe the approach to the modification 2

3 Presentation Objective Discuss the Wolf Creek Waterhammer Mitigation Modification 3

4 Project Team*Rich ClemensVice President -Strategic Projects*Russell BowieESW Project Director*TomSydnorWater Hammer Mitigation PM

• Kamran DerakhshandeganESW Project Engineer

• Larry StevensLicensing Engineer

• RichKokeshSargent& Lundy -Project Manager

• Tony RyanSargent& Lundy -Lead Engineer*Donald GrafMPR Associates -Consultant 4

5 5 Description of the Total ESW Initiative

• Buried Piping Replacement Project (BPRP)

• Above Ground Replacement Project (AGRP)*Waterhammer Mitigation Project

• ESW System Inspection and Repair Program 5 6 6 Description of the Waterhammer Mitigation Modification*The use of a bypass line around the ESW Pump discharge valve*The closure of the ESW Pump discharge valve for a fixed time period to force flow through the bypass*The locking shut of ESW cross-tie valves

• A time-delay relay in-line to ESW Pump discharge valve open signal 6

Waterhammer Phenomena*Present design results in a pressure transient (waterhammer) when ESW flow is initiated upon shutdown of the normal Service Water (SW) system 7 7 System Operation1.Initiating event2.Service water shutdown, system begins to drain down3.EDG start 4.Sequencer operation5.Cross-tie valve operation6.Start ESW pumps 7.ESW flow in bypass mode8.Main ESW Valves open, full flow of ESW 8 8 9 9 Effects of this Modification1.Reduces system column closure effects2.Reduction in pressure pulse3.Reduction in piping loads4.Remains within design specifications 9

10 10 Analytical Methods Used Computer modeling (vice hand calculation) using the same calculation methods as existing plant license

• Hydraulic network evaluation

• Void closure pressure -Joukowsky Equation 10 11 11 Conclusion*The 50.59 process has concluded that prior NRC approval not required*WCNOC intends to implement the proposed modifications to the ESW by completion of mid-cycle outage during spring of 2014.

11 12 12 Schedule for Implementation*Complete design Oct. 29, 2013*Receive valves & materials Jan. 6, 2014

• Fabrication of sub-assemblies Jan. 17, 2014

• Start outageFeb. 1, 2014

• Start-upApril 2, 2014 12 13 13 Any questions or comments?

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