ML19011A211

Revision 4 to Defueled Safety Analysis Report, Chapter 6, Engineered Safety Features

ML19011A211
Person / Time
Site:	San Onofre
Issue date:	12/06/2018
From:	Southern California Edison Co
To:	Office of Nuclear Reactor Regulation
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Download: ML19011A211 (2)

Text

San Onofre 2&3 UFSAR (DSAR)

ENGINEERED SAFETY FEATURES

6. ENGINEERED SAFETY FEATURES

6.1 INTRODUCTION

Engineered Safety Feature (ESF) Systems are no longer required to support permanent plant shutdown or defueled operations. The operational information has been removed from the UFSAR (DSAR) to indicate that the systems perform no licensing basis or design basis function.

Although the systems do not support operation, some systems may still contain fluids, gases or other hazards such as energized circuits, compressed air, radioactive material, etc. Equipment may not have been physically removed from the plant. See P&IDs, One Line Diagrams and General Arrangement Drawings for current plant configuration.

STRUCTURES/SYSTEMS/COMPONENTS STATUS Containment Building Partially Removed from Service Habitability Partially Removed from Service Containment Spray Removed from Service Emergency Operation Containment Ventilation Removed from Service Containment Isolation Removed from Service Safety Injection Removed from Service ESF Filter Removed from Service Auxiliary Feedwater Removed from Service Containment Dome Circulation Removed from Service Hydrogen Monitoring System Removed from Service Hydrogen Gas System Removed from Service Toxic Gas Isolation Removed from Service 6.2 CONTAINMENT BUILDING SYSTEMS In the permanently defueled condition, the Containment Building no longer provides an Engineered Safety Feature function. The containment building's remaining functions are passive.

1) The Updated Fire Hazards Analysis (UFHA) credits the existing structure to retain the residual radioactive material within the reactor-coolant-associated piping systems during a fire event.

2) The containment structure remains a Seismic Category 1 structure and will not interact with other Seismic Category 1 structures, equipment, or systems, e.g. Fuel Handling Building. A description of the containment and the design criteria relating to static loads, and seismic loads are provided or referenced in Chapter 3.

November 2018 6-1 Rev 4

San Onofre 2&3 UFSAR (DSAR)

ENGINEERED SAFETY FEATURES 6.3 HABITABILITY SYSTEMS In the permanently defueled condition, the Habitability Systems no longer provide an Engineered Safety Feature function. Many of the Habitability System functions are still available and the operational information is included in the UFSAR (DSAR). Specifically, the lighting systems are discussed in Chapter 9, the ventilation and air conditioning equipment is discussed in Chapter 9, and elevation and plan drawings showing building dimensions and locations are listed in Chapter 1.

The Control Room/Command Center isolation automatic response to emergency conditions is not required to support permanent plant shutdown or defueled operations. The Chapter 15 Safety Analyses do not take credit for protection of the operators. However, it can be operated manually.

6.3.1 MANUAL OPERATION The Habitability Systems for the Control Room/Command Center are located in the Control Building. The Control Building Chillers are installed on the Control Building Roof at 85 ft elevation and Unit-2 Intake Structure Roof 40 ft elevation.

November 2018 6-2 Rev 4