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

WCNOC-NRC Pre-submittal Meeting Modification to Essential Service Water System August 7, 2013 1

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

Presentation Objective Discuss the Wolf Creek Waterhammer Mitigation Modification 3

Project Team

• Rich Clemens Vice President - Strategic Projects

• Russell Bowie ESW Project Director

• Tom Sydnor Water Hammer Mitigation PM

• Kamran Derakhshandegan ESW Project Engineer

• Larry Stevens Licensing Engineer

• Rich Kokesh Sargent & Lundy - Project Manager

• Tony Ryan Sargent & Lundy - Lead Engineer

• Donald Graf MPR Associates - Consultant 4

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

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

System Operation

1. Initiating event

2. Service water shutdown, system begins to drain down

3. EDG start

4. Sequencer operation

5. Cross-tie valve operation

6. Start ESW pumps

7. ESW flow in bypass mode

8. Main ESW Valves open, full flow of ESW 8

Effects of this Modification

1. Reduces system column closure effects

2. Reduction in pressure pulse

3. Reduction in piping loads

4. Remains within design specifications 9

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

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.

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Schedule for Implementation

• Complete design Oct. 29, 2013

• Receive valves & materials Jan. 6, 2014

• Fabrication of sub-assemblies Jan. 17, 2014

• Start outage Feb. 1, 2014

• Start-up April 2, 2014 12

Any questions or comments?

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