ML13275A269

10/3/13 Presentation Slides from Meeting with Duke Energy Carolinas, LLC, Oconee Nuclear Station Units 1, 2, and 3, Protected Service Water Alternate Cooling

ML13275A269
Person / Time
Site:	Oconee
Issue date:	10/03/2013
From:	Freudenberger R Duke Energy Carolinas
To:	Office of Nuclear Reactor Regulation
Guzman R
References
Download: ML13275A269 (25)

Text

Oconee Nuclear Station Protected Service Water System - Alternate Cooling - October 3, 2013

Duke Energy Participants Dave Baxter, VP, Regulatory Project Completion Rich Freudenberger, Manager, PSW Licensing Tim Brown, Manager, Nuclear Programs Engineering Jason Patterson, Project Manager, PSW Alternate Cooling For Information Only 2

Agenda Opening Remarks Dave Baxter

Background

Rich Freudenberger Reactor and Auxiliary Building Analyses Jason Patterson Reactor Building - Alternate Cooling Jason Patterson Auxiliary Building - Alternate Cooling Jason Patterson Power - Alternate Cooling Jason Patterson Design Basis Tim Brown Closing Remarks Dave Baxter For Information Only 3

Opening Remarks Provide an overview of alternate cooling for the Protected Service Water (PSW)

System.

Discuss status of alternate cooling design and capabilities.

Focus is on NFPA 805 Confirmatory Order compliance.

Understand Staffs needs in support of completion of the PSW System Safety Evaluation Report.

4 For Information Only

Protected Service Water System PSW Building 5

For Information Only

Protected Service Water System PSW Building 13.8KV, 4160VAC and 600VAC Switchgear and Transformers 6

For Information Only

Protected Service Water System PSW Building 125VDC System Equipment 7

For Information Only

Protected Service Water System PSW Building HVAC Equipment 8

For Information Only

Protected Service Water System Keowee Unit 2 Transition Junction Box External 9

For Information Only

Protected Service Water System PSW Project Keowee 13.8KV Switchgear Cabinet 10 For Information Only

Protected Service Water System PSW Pump Room 11 For Information Only

Protected Service Water System PSW Pump and Motor 12 For Information Only

=

Background===

Reactor Building Cooling Relies on Low Pressure Service Water (LPSW) and switchgear located in the Turbine Building.

Auxiliary Building Cooling Relies on LPSW, the existing chilled water system, and switchgear located in the Turbine Building.

Protected Service Water Provides an alternate means of achieving safe and stable conditions, without reliance on systems located in the Turbine Building.

13 For Information Only

=

Background===

Heat input from larger PSW pump was recognized in early design concepts.

Detailed design identified additional heat inputs from repowered High Pressure Injection (HPI) System and vital power components.

GOTHIC Models:

• Reactor Building (RB) model existed; Upgraded to GOTHIC and a PSW specific case was created.

• Auxiliary Building (AB) model has been developed.

14 For Information Only

Auxiliary Building Analyses Auxiliary Building (AB)

AB GOTHIC model PSW case conditions

• Assumed loss of AB ventilation systems.

• Heat loads applied from operating PSW/HPI components for 30 days.

Component evaluation / upgrade

• Approximately 1300 existing and 500 new AB components have been screened for acceptability at 60 C.

• Most AB areas are less than 60 C for the first 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />. Equipment that did not pass initial screening is being further reviewed for acceptability or modification.

• Evaluation of the control complex areas is also in progress.

15 For Information Only

Reactor Building Analyses Reactor Building (RB)

GOTHIC Containment model PSW case conditions

• Mass and energy released through head vents and/or high points to accommodate Reactor Coolant System (RCS) letdown and RCS cooldown activities.

• RCS cooldown begins after 15 hours1.736111e-4 days <br />0.00417 hours <br />2.480159e-5 weeks <br />5.7075e-6 months <br /> and concludes at the end of 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />.

Component evaluation / upgrade

• Approximately 450 components identified in containment were evaluated.

• Only 7 component types were identified which could not be analytically shown to operate for the entire 30 days following a loss of containment cooling.

• All component types except one were analytically capable of allowing a delayed start of a Reactor Building Cooling Unit (RBCU) for 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />. Additional qualification/upgrade activities of this component type are being pursued.

16 For Information Only

Auxiliary Building - Alternate Cooling 17 For Information Only

Auxiliary Building - Alternate Cooling

System Description

The Alternate Chilled Water system provides alternative chilled water and support functions to Air-Handling Units (AHUs) and exhaust fans to maintain an acceptable temperature for the Control Complex and the Auxiliary Building.

The system uses 2 portable 500 ton chillers that will connect to permanently installed piping.

There are 24 existing AHUs, 13 existing fans, and 4 new AHUs available to maintain acceptable temperatures.

Operation of AWC will require manual action to:

• Start-up the chillers

• Realign AHUs to be fed by AWC chilled water

• Manually position dampers with N2 bottles/manifold

• Start the AHU fans and/or Exhaust Fans 18 For Information Only

Auxiliary Building - Alternate Cooling 19 For Information Only

Reactor Building - Alternate Cooling

System Description

Alternate cooling water capability is being provided to a Reactor Building Cooling Unit (RBCU) to maintain equipment temperature limits.

Modifications are being installed to allow connection of a portable diesel pump to provide lake water to a RBCU for containment cooling.

Deployment and startup of the alternate RBCU cooling water supply is to be performed during a scenario involving loss of containment cooling.

20 For Information Only Portable Pump Reactor Building Intake RBCU Normal Supply

Power - Alternate Cooling

System Description

Provide alternate power feed from PSW to AWC equipment and RBCUs.

Major new components: 4160V switchgear, transformers, Motor Control Centers (MCCs), transfer devices.

Normal alignment will maintain power to the 4160V switchgear and chillers.

Alternate MCCs will be de-energized until required.

Transfer devices are used to swap from normal power source to alternate power source.

All electrical operations are local/manual operations.

21 For Information Only

Power - Alternate Cooling Electrical Block Diagram 22 For Information Only

Design Basis Design Basis Alternate cooling will be included in Oconees QA-5 Program.

Alternate cooling provides extended PSW/HPI system operations to meet NFPA 805 requirements.

Existing repowered equipment from alternate cooling will maintain current quality class.

Single failure will not apply; the Standby Shutdown Facility (SSF) provides diverse safe shutdown capability.

Since the PSW system is not credited for tornado or external flood mitigation, alternate cooling will not be protected from tornadoes or external floods.

Although alternate cooling will not be seismically designed, potential seismic interactions with other safety-related systems, structures, or components will be evaluated as part of its design (II over I).

Lake Keowee will be the credited cooling water source for RB alternate cooling.

23 For Information Only

Design Basis Design Basis (cont.)

Since the PSW system is not credited for mitigation of design basis events, PSW components do not fall within the scope of 10CFR50.49.

Existing safety systems and components that interface with the PSW system will retain their qualification in accordance with 10CFR50.49.

PSW components are being evaluated for the temperature profile specific to their location crediting alternate cooling.

24 For Information Only

Closing Remarks 25 For Information Only