ML20209A380

8 to Updated Final Safety Analysis Report, Chapter 8.0, Electrical Systems

ML20209A380
Person / Time
Site:	Millstone
Issue date:	06/22/2020
From:	Dominion Energy Nuclear Connecticut
To:	Office of Nuclear Reactor Regulation
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Text

Millstone Power Station Unit 2 Safety Analysis Report Chapter 8: Electrical Systems

Table of Contents tion Title Page ELECTRICAL DRAWINGS SUBMITTED TO AEC FOR REVIEW .............. 8.0-1 ELECTRIC POWER ........................................................................................... 8.1-1 1 Introduction................................................................................................. 8.1-1 1.1 Design Criteria ............................................................................................ 8.1-2 1.2 Utility Grid.................................................................................................. 8.1-2 1.3 Interconnections.......................................................................................... 8.1-3 1.4 345-kV Switchyard System at Site ............................................................. 8.1-3 2 Off Site Power System................................................................................ 8.1-3 2.1 Description.................................................................................................. 8.1-3 2.2 Analysis ...................................................................................................... 8.1-5 2.3 Extreme Contingency Events.................................................................... 8.1-10 3 Station Blackout (SBO) ............................................................................ 8.1-10 3.1 Station Blackout Duration ........................................................................ 8.1-11 3.2 Ability to Cope with a Station Blackout ................................................... 8.1-11 4160-VOLT AND 6900-VOLT SYSTEMS........................................................ 8.2-1 1 Design Bases............................................................................................... 8.2-1 1.1 Functional Requirements ............................................................................ 8.2-1 1.2 Design Criteria ............................................................................................ 8.2-1 2 System Description ..................................................................................... 8.2-1 2.1 System......................................................................................................... 8.2-1 2.2 Components ................................................................................................ 8.2-2 3 System Operation........................................................................................ 8.2-3 3.1 Normal Operations...................................................................................... 8.2-3 3.2 Abnormal Operation ................................................................................... 8.2-3 3.3 Emergency Conditions................................................................................ 8.2-5 3.4 Startup, Shutdown and Refueling ............................................................... 8.2-6 4 Availability and Reliability......................................................................... 8.2-6 4.1 Special Features .......................................................................................... 8.2-6 4.2 Tests and Inspections .................................................................................. 8.2-6

tion Title Page EMERGENCY GENERATORS ......................................................................... 8.3-1 1 Design Bases............................................................................................... 8.3-1 1.1 Functional Requirements ............................................................................ 8.3-1 1.2 Design Criteria ............................................................................................ 8.3-1 2 System Description ..................................................................................... 8.3-1 2.1 System......................................................................................................... 8.3-1 2.2 Components ................................................................................................ 8.3-2 3 System Operation........................................................................................ 8.3-6 3.1 Emergency Operation ................................................................................. 8.3-6 3.2 Abnormal Operation ................................................................................... 8.3-7 4 Availability and Reliability......................................................................... 8.3-7 4.1 Special Features .......................................................................................... 8.3-7 4.2 Tests and Inspections ................................................................................ 8.3-11 480 VOLT SYSTEM ........................................................................................... 8.4-1 1 Design Bases............................................................................................... 8.4-1 1.1 Functional Requirements ............................................................................ 8.4-1 1.2 Design Criteria ............................................................................................ 8.4-1 2 System Description ..................................................................................... 8.4-1 2.1 System......................................................................................................... 8.4-1 2.2 Components ................................................................................................ 8.4-2 3 System Operation........................................................................................ 8.4-5 3.1 Normal Operation ....................................................................................... 8.4-5 3.2 Emergency Operation ................................................................................. 8.4-5 4 Availability and Reliability......................................................................... 8.4-5 4.1 Special Features .......................................................................................... 8.4-5 4.2 Tests and Inspections .................................................................................. 8.4-6 BATTERY SYSTEM .......................................................................................... 8.5-1 1 Design Bases............................................................................................... 8.5-1 1.1 Functional Requirements ............................................................................ 8.5-1 1.2 Design Criteria ............................................................................................ 8.5-1

tion Title Page 2 System Description ..................................................................................... 8.5-1 2.1 System......................................................................................................... 8.5-1 2.2 Components ................................................................................................ 8.5-2 3 System Operation........................................................................................ 8.5-3 3.1 Normal Operation ....................................................................................... 8.5-3 3.2 Emergency Conditions................................................................................ 8.5-4 4 Availability and Reliability......................................................................... 8.5-4 4.1 Special Features .......................................................................................... 8.5-4 4.2 Tests and Inspections .................................................................................. 8.5-5 ALTERNATING CURRENT INSTRUMENTATION AND CONTROL......... 8.6-1 1 Design Bases............................................................................................... 8.6-1 1.1 Functional Requirements ............................................................................ 8.6-1 1.2 Design Criteria ............................................................................................ 8.6-1 2 System Description ..................................................................................... 8.6-1 2.1 System......................................................................................................... 8.6-1 2.2 Components ................................................................................................ 8.6-2 3 System Operation........................................................................................ 8.6-4 3.1 Normal Operation ....................................................................................... 8.6-4 3.2 Emergency Operation ................................................................................. 8.6-4 4 Availability and Reliability......................................................................... 8.6-4 4.1 Special Features .......................................................................................... 8.6-4 4.2 Tests and Inspections .................................................................................. 8.6-5 4.3 Additional Features..................................................................................... 8.6-5 WIRE, CABLE AND RACEWAY FACILITIES ............................................... 8.7-1 1 Design Bases............................................................................................... 8.7-1 1.1 Functional Requirements ............................................................................ 8.7-1 1.2 Design Criteria ............................................................................................ 8.7-1 2 System Description ..................................................................................... 8.7-1 2.1 System......................................................................................................... 8.7-1 2.2 Components ................................................................................................ 8.7-2

tion Title Page 2.3 Cable Ampacities ........................................................................................ 8.7-3 3 Availability and Reliability......................................................................... 8.7-3 3.1 Separation ................................................................................................... 8.7-3 3.2 Tests and Inspections .................................................................................. 8.7-7

List of Tables mber Title 1 Diesel Fuel Oil System Mode Analysis 2 A Emergency Diesel Generator Loading 3 B Emergency Diesel Generator Loading 1 Battery Service Profile for Batteries 201A and 201B 1 Cable Characteristics 2 Omitted 3 Omitted 4 Facility Identification

List of Figures mber Title 1A Deleted by FSARCR MP2-UCR-2016-007 1B Hunts Brook Junction 1C 345 kV Transmission Map of Connecticut and Western Massachusetts 1D 345 kV Switchyard 2 Deleted by PKG FSC MP2-UCR-2011-010 1 Main Single Line Diagram 1 Logic Diagrams Diesel Generators (Sheet A) 2 Diesel Generator Related (Sheet 0A)

-3 Not Used 4 Diesel Generator Fuel Oil System/Auxiliary Steam Condensate and Heater Index (Sheets 1)

-5 Diesel Generators' Ancillary Systems (Sheet 1A) 1 Charging Pump - Power Supply Crossover P18B 2 Service Water Strainer ML1B Power Supply Crossover Scheme 1 Single Line Diagram 125 VDC / VAC Systems (Sheet 1) 2 Reactor Trip Switchgear Circuit Breaker Control Circuitry (Sheet 1) 1 Raceway Plans (Sheet 1)

ELECTRICAL DRAWINGS SUBMITTED TO AEC FOR REVIEW

1. Bechtel Power Corporation Electrical Drawings:

A. Single Line Diagrams Drawing Number Revision Number Sheet Number Figure Number 25203-30001 8 8.2-1 25203-30002 3 25203-30005 6 25203-30006 4 25203-30008 8 25203-30009 4 25203-30024 6 B. Elementary/Schematic Wiring Diagrams Drawing Number Revision Number Sheet Number Figure Number 25203-30011 8 20 25203-30011 10 21 25203-30011 12 22 25203-30011 10 23 25203-30011 7 26 25203-30011 10 27 25203-30011 6 28 25203-30011 8 34 25203-30011 10 35 25203-30011 10 36 25203-30011 15 37 25203-30011 10 38 25203-30011 11 39

25203-30011 11 40 25203-30011 8 41 25203-30011 16 42 25203-30011 11 43 25203-30022 5 1 25203-30022 1 2 25203-30022 4 3 25203-30022 1 4 25203-30022 4 5 25203-30022 5 6 25203-30022 5 7 25203-30022 4 8 25203-30022 5 9 25203-30022 7 10 25203-30022 6 11 25203-30022 5 12 25203-30022 7 13 25203-30022 9 14 25203-30022 7 15 25203-30022 9 16 25203-30022 7 17 25203-30022 12 20 25203-30022 3 21 25203-30022 6 22 25203-30022 7 23 25203-30022 4 26 25203-30022 1 27 25203-30022 3 28 25203-30041 3 5 25203-30044 3 1 25203-30044 2 2

25203-30044 2 3 25203-30044 2 4 25203-30044 2 7 25203-30044 2 8 25203-30044 2 9 25203-30044 15 10 25203-30044 3 11 25203-30044 5 12 25203-30044 6 16 25203-30044 7 17 25203-30044 6 18 25203-30044 7 19 25203-30051 0 A 25203-30052 3 1 25203-30052 3 2 25203-30052 3 3 25203-30052 3 4 25203-30053 11 0 25203-30053 8 1 25203-30053 4 2 25203-30053 9 3 25203-30053 4 4 25203-32002 13 0 25203-32002 7 1 25203-32002 8 2 25203-32002 7 3 25203-32002 8 4 25203-32002 5 5 25203-32002 5 6 25203-32002 5 7 25203-32002 5 8

25203-32002 5 9 25203-32002 5 10 25203-32002 5 11 25203-32002 6 12 25203-32002 5 13 25203-32002 6 14 25203-32002 6 15 25203-32002 6 16 25203-32002 6 17 25203-32002 5 18 25203-32002 6 19 25203-32002 7 20 25203-32002 3 21 25203-32002 2 22 25203-32003 1 A 25203-32003 2 B 25203-32003 6 27 25203-32003 6 28 25203-32003 2 29 25203-32003 3 30 25203-32003 4 31 25203-32003 2 32 25203-32003 2 33 25203-32003 2 34 25203-32003 5 35 25203-32003 6 37 25203-32003 8 38 25203-32003 2 39 25203-32003 3 40 25203-32003 4 41 25203-32003 2 42

25203-32003 2 43 25203-32003 2 44 25203-32004 2 A 25203-32004 5 2 25203-32004 3 3 25203-32004 3 4 25203-32004 3 5 25203-32004 2 6 25203-32004 2 7 25203-32004 3 8 25203-32004 5 9 25203-32004 5 11 25203-32004 3 12 25203-32004 3 13 25203-32004 3 14 25203-32004 2 15 25203-32004 2 16 25203-32004 3 17 25203-32008 7 A 25203-32008 0 B 25203-32008 0 C 25203-32008 4 1 25203-32008 4 2 25203-32008 5 3 25203-32008 7 4 25203-32008 8 5 25203-32008 5 6 25203-32008 5 7 25203-32008 5 8 25203-32008 3 9 25203-32008 4 10

25203-32008 5 11 25203-32008 7 12 25203-32008 6 13 25203-32008 5 14 25203-32008 5 15 25203-32008 5 16 25203-32008 5 17 25203-32008 5 18 25203-32008 5 19 25203-32008 5 20 25203-32008 5 21 25203-32008 5 22 25203-32008 5 23 25203-32008 5 24 25203-32008 6 25 25203-32008 5 26 25203-32008 5 27 25203-32008 5 28 25203-32008 5 29 25203-32008 5 30 25203-32008 4 31 25203-32008 4 32 25203-32008 3 33 25203-32008 5 34 25203-32008 4 35 25203-32008 3 37 25203-32008 8 38 25203-32008 9 39 25203-32008 9 40 25203-32008 4 49 25203-32008 3 54

25203-32008 3 55 25203-32008 2 56 25203-32008 2 57 25203-32008 2 58 25203-32008 2 59 25203-32008 3 60 25203-32008 4 61 25203-32008 2 64 25203-32008 3 69 25203-32009 5 A 25203-32009 1 B 25203-32009 4 C 25203-32009 6 4 25203-32009 7 5 25203-32009 4 6 25203-32009 4 8 25203-32009 4 9 25203-32009 4 10 25203-32009 2 15 25203-32009 2 16 25203-32009 2 17 25203-32009 2 18 25203-32009 4 21 25203-32009 5 24 25203-32009 4 25 25203-32009 7 30 25203-32009 4 31 25203-32009 5 33 25203-32009 5 34 25203-32009 1 35 25203-32009 2 36

25203-32009 1 37 25203-32009 3 38 25203-32009 4 39 25203-32009 3 40 25203-32009 5 41 25203-32009 5 42 8.4-1 25203-32009 4 43 25203-32009 1 44 25203-32009 2 45 25203-32009 1 46 25203-32009 3 47 25203-32009 2 48 25203-32012 4 B 25203-32012 0 C 25203-32012 4 11 25203-32012 4 12 25203-32012 3 13 25203-32012 1 21 25203-32012 1 22 25203-32012 1 25 25203-32012 1 26 25203-32012 0 27 25203-32012 0 28 25203-32013 5 A 25203-32013 0 B 25203-32013 5 C 25203-32013 7 5 25203-32013 8 6 25203-32013 7 7 25203-32013 3 10 25203-32013 3 16

25203-32013 3 17 25203-32013 3 18 25203-32013 7 19 25203-32013 7 20 25203-32013 5 21 25203-32013 5 22 25203-32013 5 37 25203-32013 5 38 25203-32013 3 39 8.4-2 25203-32013 5 40 25203-32013 5 41 25203-32013 5 42 25203-32013 5 43 25203-32015 6 A 25203-32015 0 B 25203-32015 8 1 25203-32015 8 2 25203-32015 8 3 25203-32015 5 8 25203-32015 6 9 25203-32015 6 10 25203-32015 5 11 25203-32015 7 12 25203-32015 7 13 25203-32015 4 14 25203-32015 2 15 25203-32015 2 16 25203-32015 2 17 25203-32015 3 18 25203-32015 3 20 25203-32015 3 21

25203-32015 3 24 25203-32015 4 25 25203-32015 2 26 25203-32015 2 27 25203-32015 3 28 25203-32015 3 29 25203-32015 7 31 25203-32015 7 33 25203-32015 7 35 25203-32015 7 37 25203-32015 4 38 25203-32015 2 39 25203-32015 3 40 25203-32015 2 41 25203-32015 2 42 25203-32015 2 43 25203-32015 2 44 25203-32015 2 45 25203-32015 2 46 25203-32015 2 47 25203-32015 1 49 25203-32017 4 A 25203-32017 1 B 25203-32017 3 7 25203-32020 6 A 25203-32020 1 B 25203-32020 8 1 25203-32020 9 2 25203-32020 2 7 25203-32020 2 8 25203-32020 3 9

25203-32020 4 11 25203-32020 4 12 25203-32020 2 13 25203-32020 4 14 25203-32020 4 15 25203-32020 9 18 25203-32020 11 20 25203-32020 10 19 25203-32020 11 21 25203-32020 1 25 25203-32020 0 27 25203-32021 5 A 25203-32021 0 B 25203-32021 5 6 25203-32021 4 8 25203-32021 3 9 25203-32021 3 10 25203-32021 4 12 25203-32021 4 13 25203-32021 4 14 25203-32021 4 15 25203-32021 2 19 25203-32021 2 20 25203-32022 24 0 25203-32022 24 00 25203-32022 24 000 25203-32022 5 A 25203-32022 2 D 25203-32022 8 1 25203-32022 8 2 25203-32022 8 3

25203-32022 8 4 25203-32022 5 6 25203-32022 2 8 25203-32022 2 9 25203-32022 6 10 25203-32022 6 11 25203-32022 6 12 25203-32022 6 13 25203-32022 6 14 25203-32022 6 15 25203-32022 7 16 25203-32022 8 17 25203-32022 8 18 25203-32022 4 19 25203-32022 4 20 25203-32022 6 21 25203-32022 5 22 25203-32022 7 23 25203-32022 8 24 25203-32022 5 26 25203-32022 5 27 25203-32022 4 28 25203-32022 4 29 25203-32022 6 30 25203-32022 5 31 25203-32022 3 34 25203-32022 5 35 25203-32022 4 36 25203-32022 5 37 25203-32022 4 38 25203-32022 4 49

25203-32022 2 40 25203-32022 3 41 25203-32022 3 42 25203-32022 4 43 25203-32022 4 44 25203-32022 6 45 25203-32022 4 46 25203-32022 4 47 25203-32022 4 48 25203-32022 3 49 25203-32022 5 50 25203-32022 2 51 25203-32022 4 52 25203-32022 5 53 25203-32022 3 54 25203-32022 3 55 25203-32022 3 56 25203-32022 3 57 25203-32022 3 58 25203-32022 4 59 25203-32022 4 60 25203-32022 5 61 25203-32022 4 62 25203-32022 5 63 25203-32022 5 64 25203-32022 3 65 25203-32022 3 68 25203-32022 2 69 25203-32022 0 70 25203-32022 2 71 25203-32022 1 72

25203-32022 3 73 25203-32022 1 74 25203-32022 2 75 25203-32022 2 77 25203-32023 9 A 25203-32023 1 B 25203-32023 4 1 25203-32023 6 2 25203-32023 6 3 25203-32023 6 4 25203-32023 7 5 25203-32023 7 6 25203-32023 8 7 25203-32023 8 8 25203-32023 6 37 25203-32023 5 38 25203-32023 8 39 25203-32023 8 40 25203-32023 7 42 25203-32023 7 43 25203-32025 3 A 25203-32025 0 C 25203-32025 1 10 25203-32025 1 11 25203-32025 2 17 25203-32026 2 A 25203-32026 0 C 25203-32026 3 1 25203-32026 3 2 25203-32027 3 A 25203-32027 0 B

25203-32027 3 3 25203-32030 1 A 25203-32030 0 B 25203-32030 4 3 25203-32030 4 4 25203-32041 2 A 25203-32041 9 1 25203-32041 9 2 25203-32041 7 3 25203-32041 5 4 25203-32041 11 5 8.3-2, Sheet 5 25203-32041 7 6 8.3-2, Sheet 6 25203-32041 7 7 8.3-2, Sheet 7 25203-32041 3 8 8.3-2, Sheet 8 25203-32041 2 9 8.3-2, Sheet 9 25203-32041 5 10 8.3-2, Sheet 10 25203-32041 6 11 8.3-2, Sheet 11 25203-32041 7 14 8.3-2, Sheet 14 25203-32041 6 15 8.3-2, Sheet 15 25203-32041 5 16 8.3-2, Sheet 16 25203-32041 10 17 8.3-2, Sheet 17 25203-32041 6 18 8.3-2, Sheet 18 25203-32041 7 19 8.3-2, Sheet 19 25203-32041 3 20 8.3-2, Sheet 20 25203-32041 2 21 8.3-2, Sheet 21 25203-32041 4 22 8.3-2, Sheet 22 25203-32041 6 23 8.3-2, Sheet 23 25203-32041 7 26 8.3-2, Sheet 26 25203-32041 3 27 8.3-2, Sheet 27 25203-32041 1 28 8.3-2, Sheet 28 25203-32041 3 29 8.3-2, Sheet 29

25203-32041 1 30 8.3-2, Sheet 30 25203-32043 4 1 25203-32043 4 2 25203-32043 5 3 25203-32043 4 4 25203-32045 4 1 8.3-2, Sheet 1 25203-32045 4 2 8.5-2, Sheet 2 25203-32045 4 3 8.5-2, Sheet 3 25203-32045 4 4 8.5-2, Sheet 4 25203-32045 4 5 8.5-2, Sheet 5 25203-32045 4 6 8.5-2, Sheet 6 25203-32045 4 7 8.5-2, Sheet 7 25203-32045 4 8 8.5-2, Sheet 8 25203-32045 4 9 8.5-2, Sheet 9 25203-32045 4 10A 25203-32045 3 10B 25203-32045 3 10D 25203-32045 4 11 8.5-2, Sheet 11 25203-32045 1 12

2. Combustion Engineering Corporation Electrical Drawings:

Drawing Number Revision Number Sheet Number Figure Number D-18767-411-022 05 D-18767-411-029 02 D-18767-411-030 00 D-18767-411-031 05 D-18767-411-035 02 D-18767-411-037 02 D-18767-411-036 02 D-18767-411-038 03

D-18767-411-366 03 D-18767-414-460 NA D-18767-414-461 NA D-18767-414-469 03 D-18767-416-103 02 D-18767-416-104 02 D-18767-416-111 02 D-18767-416-112 03 D-18767-416-131 05 D-18767-416-401 03 D-18767-416-402 03 D-18767-416-451 00 D-18767-416-470 03 1 04 2 04 3 01 4 D-18767-416-472 03 D-18767-416-481 00 E-18767-411-003 04 E-18767-411-011 03 E-18767-411-012 05 1 07 2 07 3 06 4 E-18767-411-013 04 1 03 2 04 3 02 4 E-18767-411-018 02 E-18767-411-021 05 E-18767-411-024 04

E-18767-411-025 02 E-18767-411-033 03 E-18767-411-034 03 E-18767-411- 039 05 E-18767-411-040 03 E-18767-411-043 02 E-18767-411-071 05 E-18767-411-072 06 E-18767-411-084 03 E-18767-411-102 02 E-18767-411-103 02 E-18767-411-302 03 E-18767-411-310 03 E-18767-411-323 03 1 E-18767-411-323 03 2 E-18767-411-324 04 E-18767-411-325 03 E-18767-411-350 03 E-18767-411-376 02 E-18767-411-400 04 E-18767-411-401 03 E-18767-413-012

1 INTRODUCTION s chapter describes the utility grid and its interconnections to other grids and to the Millstone lear Power Station 345 kV switchyard. The on site electric system is also described.

initions used in this chapter are given below.

nsmission System transmission system includes all transmission lines coming to the Millstone Nuclear Power ion complex up to, but not including, the point of connection to the 345 kV switchyard.

Site System off-site system includes the transmission system and the 345 kV switchyard and extends up but does not include, the main transformer bank. Included in the off site system are the reserve ion service transformers, Millstone Units 2 and 3.

Site System on-site system includes the Millstone Unit 2 electric power systems out to, and including, the n transformer bank (Figure 8.2-1); this includes the normal station service transformer.

table generator connection points have been provided on several plant electrical buses. These nections are defense-in-depth features available for coping with an extended loss of AC power AP) event. The connections are shown on Figure 8.2-1, Main Single Line Diagram and ure 8.5-1, Single Line Diagram.

mal Operation mal operation is when the main generator is transmitting electrical power through the main sformer bank and when plant auxiliaries are being supplied from the normal station service sformer.

mal Power System normal power system includes that equipment required to support the main turbine generator, t systems, and equipment associated with the reactor.

ergency Power System emergency power system includes that electrical distribution equipment required to support safe shutdown and post-accident operations of Millstone Unit 2. Included in the emergency er system are the emergency 4160 V switchgear and all extensions except those going to the

ndby Power System standby power system includes the Class 1E emergency diesel generators, which are referred s the on-site emergency power supply.

erred Power System preferred off site power supply is from the 345 kV switchyard and the reserve station service sformer.

rnate Off Site Source alternate off site source is the 4160-V tie to Millstone Unit 3 via bus 34A or 34B.

1.1 Design Criteria 345 kV switchyard and the associated transmission lines provide the off site sources that are preferred power supplies, as outlined in Section 5.2.3 of IEEE Standard 308-1971 and erion 17 of Appendix A of 10 CFR Part 50. The conventional and accepted design of these lities has been shown to be conservative and reliable.

nsmission facilities connecting the Millstone generating units to the main transmission grid are gned in accordance with the Design and Operation of the Bulk Power System, developed by Northeast Power Coordinating Council (NPCC).

1.2 Utility Grid utility electrical system consists of interconnected diverse energy sources including fossil ed, hydro-electric and nuclear fueled plants supplying electric energy over a 345/115 kV smission system (Figure 8.1-1C).

-New England is the regional transmission organization which has authority over the ration of the transmission system in Connecticut. The main transmission system fed by lstone Power Station is part of the New England power system. The Connecticut Valley ctric Exchange (CONVEX) is one of the local control centers in New England and assists

-New England in running the power system in Connecticut.

electrical output of Millstone Unit 2 is delivered to the 345 kV switchyard (Figure 8.1-1D).

r 345 kV transmission lines feed power to the 345 kV system. Two of these lines feed the ern part of Connecticut by connecting respectively to the Card and Montville substations. The aining two lines feed the central part of Connecticut by connecting to the Haddam and nchester substations.

lstone Power Station is connected to the Eversource Energy, Inc. transmission system which is ely integrated with transmission systems of several other utilities and operating companies.

New England power system is part of the larger northeast interconnection power grid and is through various connections points throughout New England. These interconnections include kV, 230kV, 138kV, 115kV, 69kV, and DC lines. The New England power system is also tied to hboring grids such as New York, Hydro Quebec and New Brunswick, which are under the trol of other reliability coordinators within the NPCC region.

1.4 345-kV Switchyard System at Site 345 kV switchyard is designed in an arrangement as shown on Figure 8.1-1D. The tchyard consists of ten 345 kV breakers, four 345 kV transmission Units 2 and 3 lines, two 345 tie lines to the generator step-up transformers, and two 345 kV tie lines to the reserve station ice transformers. The Millstone 1 generator step-up transformer and reserve station service sformer are no longer in service.

breakers and motor-operated disconnect switches are controlled primarily from CONVEX the Supervisory Control and Data Acquisition System (SCADA) and from the Millstone Unit ontrol Room. Millstone 2 Operations is responsible for the switching and tagging of ipment located in the Millstone 1 Control Room. Via the Millstone Unit 1 Control Room lstone 2 Operations has primary control of breakers 8T, and 9T, as well as indication only of remaining breakers and motor-operated disconnect switches. The Millstone Units 2 and 3 trol Rooms are equipped with remote panels that show the status only of the breakers and or-operated disconnect switches in the switchyard. Through the operation of control switches, reakers can be operated at the switchyard, if necessary.

h element of the Millstone bus and associated line terminations are protected by redundant of primary and backup relays. The primary and backup relays are supplied from separate DC rces, separate current transformers, separate coupling capacitor voltage transformers, and munication channels.

DC power is supplied by two independent batteries, one primary and one backup. Each ery is equipped with its own charger and distribution panel. A manual transfer scheme is vided to allow one battery and charger to carry the DC load upon the failure of the other ery and charger.

2 OFF SITE POWER SYSTEM 2.1 Description off site power system is designed to provide reliable sources of power to the on site AC er distribution system adequate for the safe shutdown of the unit. Details of the 345 kV tchyard are shown on Figure 8.1-1D.

uits and two station service circuits. The Millstone 1 generator and station service circuits are onger in service.

four transmission line circuits terminated at the switchyard are:

a. Millstone to Haddam (Line Number 348, this line includes Line 3252)

b. Millstone to Card (Line Number 383)

c. Millstone to Montville (Line Number 371, this line includes Line 364)

d. Millstone to Manchester (Line Number 310) se circuits connect the station to the 345 kV system transmission grid and follow a common t-of-way from Millstone to Hunts Brook Junction (9.0 miles).

se four circuits are individually mounted on separate structures which are installed across a

-500 foot wide Right of Way to provide adequate physical independence of the transmission

s. The transmission towers, which support the four lines, consist of a combination of steel and den mono-pole structures, and steel and wooden H-frame structures. The towers are designed he National Electric Safety Code Part C2, and Eversource Overhead Transmission Line ndards, which have both strength and overload design factors to provide for conservative gns. The towers for all four transmission lines are periodically inspected for proper physical dition.

h four lines feeding the Millstone Switching Station in service, the offsite power source plies with GDC-17 with no reasonable failure that can affect all circuits in such a way that e of the four circuits can be returned to service in time to prevent fuel design limits or design ditions of the reactor coolant pressure boundary from being exceeded. In particular, a uence of cascading events from a particular tower falling in a specific manner, at one of only a specific locations, or a line falling at Hunts Brook Junction, the worst case would be the loss wo circuits.

four of the 345 kV lines leaving Millstone cross over two 115 kV circuits which supply the terford Substation, and constitute the off site source for Millstone Unit 1. However, the hanical failure of a single 345 kV line, and the consequential failure of the 115 kV circuits not affect the preferred source of off site power to Millstone Units 2 and 3.

Hunts Brook Junction, the four transmission line circuits diverge along three separate rights-way (Figure 8.1-1B). The 348 line turns west to the Haddam Substation, the 383 and 310 lines tinue north to the Card Street and Manchester Substations, respectively, and the 371 line turns to Montville Substation. At this junction, aerial crossover of lines exist (line 383 and line 310 s over line 371/364); however, at worst, only two of the four circuits from the Millstone tching Station would be removed from service should a structure collapse or a conductor drop.

arate structures. These circuits are supplied from different bus positions in the switchyard, so ed that no single equipment or component failure would remove both circuits from service at time.

inspection and testing of the 345 kV circuit breakers and the transmission line protective ying are done on a routine basis, without removing the transmission lines from service. The lating oil for the transformers (main step up, normal station service transformer (NSST),

rve station service transformer (RSST)) is sampled and tested on a routine basis. During these ine inspections and tests, the operability and functional performance of the electric systems verified.

2.2 Analysis possibility of power failure due to contingencies in the connections to the system and the ciated switchyard is minimized by the following arrangements:

a. The connections to the system have been designed to comply with the NPCC Design and Operation of the Bulk Power System and the ISO New England Reliability Standards for the New England Area Bulk Power Supply System.

Compliance with these criteria ensure that the supply of off-site power will not be lost following contingencies in the interconnected transmission system. Transient stability studies have been performed to verify that widespread or cascading interruptions to service will not result from these contingencies. In addition, the loss of Millstone Unit 2 or the loss of any other unit in the system will not result in cascading system outages and thus will not cause loss of off-site power to units 2 and 3.

The 345 kV circuit breakers are SF6 puffer type and are pneumatically operated.

Electrical controls are provided for both local and remote Millstone 1 control room or CONVEX operation. Each power circuit breaker has a separate pneumatic supply unit capable of operating the breaker for a minimum of three close-open operations after the loss of its pneumatic supply unit. The essential AC station service for the power circuit breaker pneumatic supply units and the other switchyard requirements is supplied by an off site 23 kV line which has transfer capability to a source from Millstone Unit 3. The circuit breakers are equipped with a closing solenoid and two independent trip solenoids. A standard anti-pump and trip-free control scheme is used.

Two 125 VDC batteries are located in the switchyard control and relay enclosure for switchyard relaying and control. Each battery has its own charger and DC distribution panel. The redundant batteries and protective relaying systems are physically and electrically separate.

switchyard main buses, surge arrestors at the transformer high voltage bushings, and rod gaps on the line terminals.

c. Each 345 kV transmission line is protected from phase to phase and phase to ground faults by two sets of diverse protective relays, one primary and one back-up, both of which are high speed schemes.

The primary line protection consists of a distance relaying package in a directional comparison blocking scheme communicating with the remote terminal over a carrier current channel.

The backup line protection consists of step-distance relays operating independently from the remote terminal. This equipment is used with a transfer trip channel to provide a high speed permissive over-reaching scheme. A second transfer trip scheme provides tripping of the breakers at the remote terminal in the event of a stuck breaker at Millstone as well as tripping Millstone breakers following the reception of a trip signal from the remote end.

Pilot wire relaying is used for primary protection of the 345 kV tie lines between the switchyard and the main step-up transformers. Backup protection consists of directional distance, single zone and directional ground overcurrent relays located in the switchyard and for transfer tripping to the plant dual channel digital teleprotection equipment is used.

Tripping of the switchyard breakers following the operation of the generator or main step-up transformer bank primary and backup relays is accomplished by the means of the transfer trip via pilot wire and digital teleprotection.

The Millstone 2 RSST 345 kV tie line is protected by two sets of protective relays, one primary and one backup. The directional distance relays detect phase-faults, and the directional ground overcurrent relays detect ground-faults. Operation of these relays will trip the appropriate 345 kV circuit breakers on the A switchyard bus, and send a transfer trip signal via digital teleprotection system with fiber optics communications medium to trip the transformers low side circuit breaker at the plant. The operation of any of the RSST transformer protective relays at the plant will trip the low side breaker, and send a transfer trip signal via digital teleprotection system with fiber optics communications medium to trip the appropriate switchyard breakers.

Primary and backup breaker failure relays are provided for each of the 345 kV circuit breakers to trip adjacent breakers in the event that the primary breaker fails to trip. The DC power for breaker failure operation is supplied from the primary and backup battery systems, respectively.

period has expired, tripping of the adjacent breaker will take place.

Phase angle sensitive impedance relays are also included in the backup protection of the main step-up transformer bank tie lines to protect the generator.

Automatic reclosing of 345 kV breakers is allowed following the protective relay tripping of the 345 kV transmission lines. The reclosing is designed for time delay reclosure from the remote ends only. At the switchyard, the breakers will close via synch-check scheme.

A synch-check scheme is also provided for each circuit breaker to supervise both manual closing and automatic reclosing of the breaker.

d. Primary and backup relaying is provided for each circuit breaker along with breaker failure protection. These provisions permit the following:

1. Any circuit can be switched under normal or fault conditions without affecting another circuit.

2. Any single circuit breaker can be isolated for maintenance without interrupting power or protection of any circuit.

3. Short circuits on any section of a bus are isolated without interrupting service to any element other than those connected to the faulty bus section.

4. The failure of any circuit breaker to trip within a set time initiates the automatic tripping of the adjacent breakers and thus may result in the loss of a line or generator for this contingency condition; however, power can be restored to the good element in less than eight hours by manually isolating the fault with appropriate disconnect switches.

mplete battery failure is considered highly unlikely since two independent 125 VDC battery ems are provided. Failure of a single battery system results only in a momentary loss of one of protective relays until the DC is manually transferred to the other battery. Therefore, no le failure could negate the effectiveness of the relaying to clear a fault.

Millstone design provides two off site circuits between the switchyard and the 4.16 kV Class buses. The immediately available off site supply is the Millstone Unit 2 RSST while the rnate supply is the Millstone Unit 3 bus 34A or 34B.

normal supply to the plant with the plant on line is the NSST. If this source is lost due to a t trip, a fast bus transfer scheme connects the plant electrical system (6.9 kV and 4.16 kV) to RSST. The second or alternate source of off site power is available by manual controls to lstone Unit 3 bus 34A or 34B for 4.16 kV power.

ultaneous failure of all power sources (reserve station service supply, standby AC emergency erators, and Millstone Unit 3 bus 34A or 34B.

345 kV transmission system supplying off site power to Millstone is normally operated at kV at Millstone. This system voltage is controlled by varying the reactive power generation the Millstone Power Station units. The Millstone Units 2 and 3 operators control the unit itation as specified by CONVEX Operation Instruction Number 6913. The unit operators are uired to balance the reactive power output of the units.

CONVEX system operator supervises the system reactive power dispatch. The CONVEX rator directs the loading of all the reactive power sources in CONVEX to balance the reactive ply. The CONVEX operator keeps the Millstone Power Station reactive power generation in nce with the Eastern Area requirements so that the effect on the system of voltage variations inimized when a unit is lost.

objective of the reactive power dispatch is to prevent the voltage at the Millstone Power ion from going below the minimum required to support actuation of the Engineered Safety tures equipment. A switchyard voltage of 345 kV will assure successful actuation and ration of all necessary safeguards loads in the unlikely event Millstone Unit 2 experiences a s-of-Coolant Accident and trips off the transmission system. CONVEX operates the system to re that this minimum voltage requirement will be met, following the loss of the unit. When in ctor Modes 5 or 6, with the auxiliary electrical system lightly loaded, Millstone Unit 2 can re successful actuation and operation of all necessary safeguards loads with a switchyard age of 335 kV. The maximum allowable voltage at Millstone Station is 362 kV based on ipment ratings.

bnormal system conditions result in voltages approaching minimum levels, system operating ructions and procedures direct the CONVEX operator to take specific corrective actions to ore voltage.

ual experience and system simulations show that the CONVEX operator is able to control the em voltages within the desired limits.

Millstone plant is connected to the transmission system by four 345 kV circuits (described in tion 8.1.2.1). Transmission operating procedures are in place to ensure that no more than the imal number of circuits would ever intentionally be taken out of service, except in an rgency, when both Millstone generating units are on-line.

oth Millstone units 2 and 3 are on line at full output, certain contingencies on the transmission em as determined by CONVEX result in procedural restrictions on the stations net output, in er to assure that system synchronous and voltage stability will be maintained.

careful design of the switchyard and protective relays, the possibility of the simultaneous loss oth units 2 and 3 at Millstone has been significantly reduced. The system has been computer

ng both on-line units simultaneously is extremely small because of the preventive measures ussed in the following paragraphs. Accordingly, the Licensee believes it is reasonable to count n on site power sources to supply the necessary station service power requirements in the very ote event that both Millstone units 2 and 3 should be lost at once accompanied by the total loss he transmission supply to the station.

rimary objective in designing the connection of the Millstone Nuclear Power Station to the kV transmission network in Connecticut has been to prevent the loss of the entire station put. The reliability criteria of NPCC and ISO New England are a fundamental part of this gn process. The most severe outage which the system has been designed to survive in order to imize the possibility of a total plant outage is as follows:

h any one of the four Millstone 345 kV transmission circuits out of service the plant remains le for any three-phase fault normally cleared (four cycles) or any one-phase fault with the yed clearing (eight cycles).

Millstone units are connected to the large interconnected transmission system in the eastern of the United States. The interconnected system frequency is maintained at 60 +/- 0.03 Hz in ordance with NPCC standards for the bulk power system. The system is designed and operated h that the loss of the largest single supply to the grid does not result in the complete loss of erred power. The system design considers the loss, through a single event, of the largest acity being supplied to the grid, removal of the largest load from the grid, or loss of the most cal transmission line. This could be the total output of a single Millstone reactor unit, the est generating unit on the grid, or possibly multiple generators as a result of the loss of a mon transmission tower, transformer, or a breaker in a switchyard or substation.

rder to ensure the interconnected system will remain stable and offsite power circuits meet C-17 requirements, the following technical requirement actions and generation output rictions will be implemented when both Millstone Power Station Unit 2 and Unit 3 are at er:

h any of the 345 kV offsite transmission lines (310, 348 (includes 3252 line), 371 (includes line), and 383) out of service or nonfunctional, the nonfunctional transmission line shall be ored to functional status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or total station output shall be reduced to 650 MWe net within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />; or, alternatively, within 7 days for Lines 310, 348/3252, 383 or 14 days for Line 371/364 with the following action requirements in place:

a. Once per shift, verify the remaining lines are functional,

b. Once per shift, perform a weather assessment,

c. Once per 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, verify the EDGs are operable and the SBO diesel is available.

put shall be reduced to < 1650 MWe net within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> to ensure the stability and ilability of the electrical grid is maintained.

h two 345 kV offsite transmission lines nonfunctional, total output shall be reduced to 650 MWe net within the next 30 minutes.

allowed outage times (AOT) for Lines 310, 348/3252, 371/364, and 383 are based on the figuration of the transmission lines at Hunts Brook Junction where Lines 383 and 310 cross r Line 371/364 and Line 348/3252 runs to the west of the crossover. With Line 348/3252, 310, 83 nonfunctional, the possibility exists that either Line 383 or 310 could drop on Line 371/364 result in three lines nonfunctional. This condition would impact grid stability and therefore, a ay AOT is allowed with the specified action requirements in place. When Line 371/364 is functional, if either Line 310 or 383 drops, two transmission lines remain functional.

refore, a 14-day AOT is allowed with the specified action requirements in place.

2.3 Extreme Contingency Events design of the switchyard protective relay schemes and circuit breaker installations is such that ost only one pole or phase of a three-phase circuit breaker will fail to clear a fault. Breakers ch are designed to meet this criteria are classified as having independent pole tripping.

ependent pole tripping is ensured by installing breakers with mechanically independent poles two separate methods of tripping the circuit breaker. These installations include two sets of ys, trip coils, and two sets of current and potential transformers. The wiring for the relay kages are installed in separate duct banks, the relay packages are physically separated in the trol house and two separate DC supplies are provided.

breaker failure schemes are physically separated in accordance with NPCC Regional iability Reference Directory #4, Bulk Power System Protection Criteria, with the exception mited legacy wire routing as permitted by Directory #4 allowance.

345 kV switchyard at Millstone is designed so that the loss of more than one transmission uit due to a failure of a breaker to trip requires at least two circuit breakers to simultaneously to operate. The failure of even one circuit breaker is very unusual. At least three circuit kers would have to fail before three transmission lines would be lost due to malfunctions in switchyard.

3 STATION BLACKOUT (SBO)

July 21, 1988, the Code of Federal Regulations 10 CFR Part 50, was amended to include tion 50.63 entitled Loss of All Alternating Current Power, (Station Blackout [SBO]). The O rule requires that each light-water-cooled nuclear power plant be able to withstand and ver from a SBO event of specified duration, requires licensees to submit information as ned in 10 CFR Part 50.63, and requires licensees to provide a plan and schedule for formance to the SBO rule. The SBO rule further requires that the baseline assumptions,

delines and Technical Bases for NUMARC Initiatives Addressing Station Blackout at Light ter Reactors; and (3) NUMARC 87-00 Supplemental Questions/Answers and Major umptions dated December 27, 1989 (issued to the industry by Nuclear Management and ources Council, Inc. [NUMARC], dated January 4, 1990).

3.1 Station Blackout Duration lstone Unit 2 has the ability to cope with a loss of preferred and emergency on-site AC power rces for up to eight hours. Unit 2 must provide decay heat removal during the event. It is med that there will be no AC power available during the first hour of the SBO except for ery backed power supplies (i.e., vital 120V AC). Within the first hour, Millstone Unit 2 will e an alternate AC power source available from Millstone Unit 3 Alternate AC (SBO) diesel erator.

lstone Units 2 and 3 each have two emergency diesel generators in addition to the Unit 3 ernate AC (SBO) diesel generator. In accordance with the SBO Rule and NUMARC 87-00, of the four emergency diesel generators would be available and a Station Blackout is tulated to occur at one unit only at any one time. In the event of a Unit 2 station blackout, the t 3 AAC diesel will be made available within one hour by Unit 3 operator action and nected to Unit 2 Bus 24E by Unit 2 operator action.

3.2 Ability to Cope with a Station Blackout ht-hour coping assessments were performed for the 1) condensate inventory available for ay heat removal, 2) Class 1E battery capacity, 3) compressed air capability, 4) effects of loss of tilation, 5) containment isolation, 6) emergency lighting, 7) communications, and 8) heat ing. The results of these assessments are summarized below.

densate Inventory Available for Decay Heat Removal alculation was performed to determine the available volume in the Condensate Storage Tank T) for decay heat removal during SBO. The necessary condensate inventory required for ay heat removal plus cooldown is less than the Technical Specification minimum requirement the CST, including consideration of required turbine driven auxiliary feedwater pump NPSH.

refore, the Millstone Unit 2 condensate inventory would be adequate for decay heat removal ng an 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> station blackout.

ss 1E Battery Capacity assessment was performed to ensure that the unit has adequate battery capacity to support uired DC loads during a SBO. It is assumed that one battery charger will be returned to service hin one hour when the alternate AC source is available. The DC power requirements for a ion blackout were calculated using the methodology of IEEE-STD-485, Recommended ctice for Sizing Large Lead Storage Batteries for Generating Stations and Substations. This

ntenance, Testing, and Replacement of Large Stationary Type Power Plant and Substation d Storage Batteries. This methodology calculates battery load requirements for various ions of time. The magnitude of DC loads for each section of time is referred to as the section

. Various section sizes are calculated in order to construct a battery duty cycle.

assessment concluded that the Class 1E batteries have adequate capacity to supply the uired DC loads for eight hours during a station blackout.

mpressed Air Capability Millstone Unit 2 air operated valves are relied on to cope with a station blackout for eight rs. Long term decay heat removal will be accomplished by manual operation of the ospheric dump valves. The auxiliary feedwater regulating valves will fail open on loss of air, auxiliary feedwater flow will be controlled by varying the speed on the auxiliary feedwater p turbine.

Effects of Loss of Ventilation ailed room heat-up calculations were performed for different areas of the unit containing ion blackout equipment which would have post-SBO 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> steady state ambient air peratures greater than 120°F. An area containing SBO equipment with a final temperature in ess of 120°F would be considered a dominant area of concern.

MARC 87-00 calculation methodologies were utilized to the maximum extent possible to litate compliance with the SBO requirements. However, in most cases different methods had be used. These methods used either a computer generated calculation of room/area peratures over time, or a manual calculation of steady state temperatures. Either method is e conservative than the NUMARC methodology.

dominant areas of concern, the SBO equipment contained in the area is either qualified for the ironment, or a reasonable assurance of operability has been provided.

tainment Isolation tainment isolation valves have been reviewed to verify that valves which must be capable of g closed or that must be operated (cycled) under SBO conditions can be positioned (with cation) independent of the Millstone Unit 2 preferred or Class 1E AC power supplies. No t modifications nor associated procedure changes were required to ensure that appropriate tainment integrity can be provided under SBO conditions.

ergency Lighting ergency lighting was evaluated to ensure that the unit has sufficient emergency lighting for onnel to safely perform the operations required for an orderly safe shutdown of the unit

s where operators maintain safe plant operations; areas where operators maintain the plant in fe shutdown conditions; and access/egress routes to accomplish these functions. The 1.5-hour d, life safety battery units provide additional portable emergency lighting for ingress / egress plant areas during a SBO Event.

mmunications assessment was performed to ensure that the unit has sufficient reliable effective munications systems available to plant personnel during SBO.

t Tracing evaluation was performed to determine the effects of a loss of electric heat tracing to systems ntial to plant shutdown during SBO and to systems that are returned to service when power is ored. Existing electric heat tracing is adequate for coping with the eight hour SBO for systems uired for safe shutdown excluding the local level instrumentation on the CST. However, an rnative method is available for determining CST level.

Figure deleted by FSARCR MP2-UCR-2016-007 FIGURE 8.1-1B HUNTS BROOK JUNCTION MASSACHUSETTS ision 3806/30/20 MPS-2 FSAR 8.1-17 Figure deleted by FSARCR MP2-UCR-2011-010 1 DESIGN BASES 1.1 Functional Requirements m either of two full capacity station service transformers, power is supplied to two 6900 volt es and to six 4160 volt station service buses. The 6900 volt switchgear feeds motors of 3000 sepower and larger. The 4160 volt switchgear feeds large (250 to less than 3000 hp) motors supplies power to 480 volt load center transformers. Additional sources of 4160 volt power from the emergency diesel generators, and from the Unit 3 reserve station service transformer nit 3 Normal Station service transformer (backfeeding).

1.2 Design Criteria e of the 6900-volt equipment is required for safety related services, but three of the 4160-volt tchgear groups are part of Class 1E systems as defined in IEEE Standard 308, 1971. The ss 1E switchgear has been designed, built and tested in accordance with Sections 4 and 5.2 of E Standard 308, 1971, Criteria 1, 2, 3, 17 and 18 of Appendix A of 10 CFR Part 50, seismic eria as defined in Sections 5.8.1 and 5.8.1.1 of this report, and Safety Guide 6.

2 SYSTEM DESCRIPTION 2.1 System 6900 volt system, shown in Figure 8.2-1, is a reliable source of power for the reactor coolant condensate pumps. The system consists of two buses, 25A (H1) and 25B (H2) each capable being fed from the 6900 volt winding of either the normal or the reserve station service sformer. The 6900 volt winding of each transformer is sized to supply the full-load uirements of both buses.

4160-volt system, shown in Figure 8.2-1, consists of five buses, 24A (A1), 24B (A2), 24C

), 24D (A4), and 24E (A5), each consisting of a metal-clad switchgear assembly with vertical air circuit breakers. The 4160-volt system provides a reliable source of power to large AC ors and to 480-volt load centers. During plant operation, power is supplied to buses 24A (A1) 24B (A2) from the normal station service transformer. Bus ties connect buses 24A (A1) and (A2) to buses 24C (A3) and 24D (A4), respectively. During other periods, such as startup and tdown when the normal station service transformer is not used, power is supplied from the rve station service transformer directly to buses 24C (A3) and 24D (A4) and via the bus ties to es 24A (A1) and 24B (A2). The 24E (A5) bus may be fed from either bus 24C (A3) or 24D

), or from Unit 3 reserve station service transformer or Unit 3 normal station service sformer (backfeeding). All auxiliary loads (other than the 6.9 kV motors detailed above) are plied from the 4.16-kV buses. Motors of 250 horsepower and larger are connected directly to 4.16 kV system; other loads are supplied at 480 volts from 4160-480 volt unit substations;

/208 volt sources are available by stepping down from 480 volts.

6900 volt switchgear for buses 25A (H1) and 25B (H2), and 4160 volt switchgear for buses (A1) through 24E (A5) and Unit 3 buses 34A and 34B consist of indoor, free standing, metal units containing vertical lift air circuit breakers and necessary auxiliaries; all located in a ss I structure. Overcurrent and motor overload protection is provided by an overcurrent relay h instantaneous attachment, and a ground fault sensor relay on each feeder.

equipment is all of General Electric Company manufacture, and its principal components are d as follows:

6900 Volts Component Amperes Continuous MVA Interrupting s 2000 eder breakers, main 2000 500 eder breakers, motor 1200 500 4160 Volts Buses 24A (A1) - 24D Bus 24E Component (A4) (A5) Buses 34A, B, C, D s (amp cont) 2000 1200 3000/2000 in feeder breakers (amp cont) 2000 1200 3000 her feeder breakers (amp cont) 1200 1200 1200 circuit breakers (MVA inter) 250 250 350 es 24C (A3), 24D (A4), and 24E (A5) are emergency buses that supply power to equipment uired for a LOCA or other transient and conform to the requirements for Class 1E equipment.

ere means exist for manually connecting together redundant load groups, interlocks are vided as directed by Safety Guide 6 to prevent an operator error that would parallel the dby power sources. In addition to electrical interlocks, a Kirk Key Interlock System is utilized he feeder breakers to bus 24E (A5). This operates on the principle that the key required to e one breaker can be removed from the second breaker only when its locking bolt is in a determined (breaker open) position. The key must be removed from one lock before another can be operated.

a. The stresses developed from combined seismic and normal loads do not exceed normal design stresses and are less than the allowable values specified in the American Institute of Steel Construction, Steel Construction Manual.

b. The deflections in structural members under combined horizontal and vertical acceleration forces are not large enough to introduce the possibility of breaker dropout.

c. The lowest natural frequency in the breaker support system is 19 hertz.

d. The breaker operating mechanism will withstand acceleration forces up to 44 g without false tripping or closing.

e. When vibrated in the frequency range of 0 to 37 hertz, door mounted LAC 66 relays tested on the factory floor were found to function normally; that is:

The contacts did not close due to vibration when the relay was not energized, and The relays operated correctly when energized above their pickup setting.

3 SYSTEM OPERATION 3.1 Normal Operations ing normal operation, the source of electric power for plant auxiliaries is from the normal ion service transformer. This transformer is a forced oil/air-cooled three-winding unit rated 45 A, with its primary connected to the generator isolated phase bus. One secondary winding s the 4160 volt system and the other supplies the 6900 volt system.

ing a normal startup the reserve station service transformer is used. After the main generator is chronized with the system, the operator will manually initiate live transfer of the auxiliary load m the reserve station service transformer to the normal station service transformer. The circuit terlocked and arranged to permit only a momentary parallel. Prior to shutdown, the operator reverse the procedure before unloading and disconnecting the main generator from the em.

3.2 Abnormal Operation reserve station service transformer is a similar 60 MVA three-winding unit with its primary directly from the 345 kV station switchyard. It is the preferred source during startup and ods when the main turbine generator is off-load.

age from the normal station service transformer and will initiate a transfer for conditions such turbine or generator trip.

transfer is high speed and considered simultaneous. It is not a supervised scheme. That is, the ondary breakers for both the normal station service transformer and reserve station service sformer receive essentially simultaneous signals to open and close, respectively. It should be ed there exists an interposing relay that provide a close permissive in the reserve station ice transformer secondary breaker closing circuit, and starts an 8 cycle timer. The timers ction is to verify that all breaker close permissives have been accomplished within the cified 8 cycle time frame. In the unlikely event that these permissives have not been met hin the allowed 8 cycle time frame, the fast transfer scheme will NOT be permitted. In the kely case that a phase displacement in excess of a predetermined value exists between the mal and alternate source voltages, PRIOR to the fast transfer signal being generated, the matic transfer is also prohibited. The transfer to the reserve station service transformer is her prohibited if there is no voltage on its secondary side, or if the source is faulted. The fast sfer scheme has been demonstrated by test to result in a total dead bus time of less than six les.

RSST has an on load tap changer (OLTC) that allows for changing the 4.16kV winding tap hout taking the transformer out of service. When the RSST connects to the plant electrical em, this allows for changing the voltage on the 4.16kV bus and maintaining design system voltage.

ervoltage protection for the emergency buses is provided via the Engineered Safety Features uation System (ESAS), which is discussed in FSAR Section 7.3. Undervoltage protection sists of two independent schemes (one for each 4160 Volt emergency bus 24C (A3) and 24D

)). Relay contacts from the ESAS undervoltage actuation logic provide outputs to control uits for automatic bus load shedding, and start of emergency diesel generators.

evel 1 undervoltage actuation (loss of voltage) provides a trip signal to the RSST supply ker to the emergency bus and the normal to emergency bus tie breaker, initiates breaker trips automatic load shedding, and provides a start signal for the emergency diesel generator ciated with that bus.

evel 2 undervoltage actuation (degraded voltage) provides a trip signal to the RSST supply ker to the bus. When a 4160 Volt emergency bus is fed from the RSST during degraded age conditions, this breaker trip results in a loss of power to the bus and a subsequent Level 1 ervoltage actuation.

evel 2 undervoltage actuation does not initiate a trip of the normal to emergency supply ker and, as such, does not isolate the power supply from the NSST. When a 4160 Volt rgency bus is fed from the NSST during degraded voltage conditions, operator actions are d to prevent damage to safety-related equipment, in accordance with operating procedures.

sformer and resistor. Both are effective low-impedance grounds which will limit ground fault ents to less than 400 and 200 amperes, respectively. All load feeders and bus feeders are vided with ground fault trip protection.

3.3 Emergency Conditions en off site power is not available, redundant emergency diesel generators are available to ply power to the emergency 4160 volt buses. A full description of this power source is given in tion 8.3.

ould be postulated that on site emergency power is being used following an accident because he lack of availability of power from the Unit 2 reserve station service transformer. To relieve diesel generator of continued post-incident operation in such a case, it is possible (by operator trol) to bring off site power to Unit 2 via Unit 3 bus 34A or 34B through the Unit 3 reserve ion service transformer, or the Unit 3 normal station service transformer (backfeeding).

160V crosstie from Unit 3 is provided to the 24E (A5) bus from the Unit 3 reserve station ice transformer or Unit 3 normal station service transformer (backfeeding). This feeder is d to provide sufficient power to place the unit in a safe shutdown condition or to provide uired minimum post accident power requirements. The 24E (A5) bus also serves as a sferable power source for spare units of emergency equipment. It supplies power for the owing components:

a. Service water pump P5B

b. Reactor building closed cooling water pump P11B

c. High-pressure safety injection pump P41B 24E (A5) bus is connected to either the 24C (A3) or 24D (A4) bus. However, both electrical mechanically operated key interlocks prevent connecting bus 24E (A5) to both bus 24C (A3) 24D (A4) simultaneously. The same interlock scheme is arranged to transfer the source of trol power so that the control power for bus 24E (A5) is from the same redundant system as control power for the bus to which it is connected. When a piece of equipment is out of service maintenance, such as the service water pump P5A, its control switch on the main control rd will be in the LOCK-OUT position (pull-to-lock), and the 24E (A5) bus will be nected to the 24C (A3) bus to allow the spare pump to be energized. The diesel generator load uencer is so enabled through interlocks with the bus 24E (A5) tie breakers that pump P5B will t on a safety injection actuation signal (SIAS) in place of pump P5A.

conditions of normal startup, shutdown, or refueling of the unit, all station auxiliary power is plied from the 345 kV network through the Unit 2 reserve station service transformer or ugh the NSST via the Main Generator Step up Transformer with the generator links removed.

4 AVAILABILITY AND RELIABILITY 4.1 Special Features ety related components are duplicated and their power supplies and distribution systems are nged to ensure that neither a failure of a bus, nor the failure of equipment connected to a bus luding the diesel generator), will prevent proper operation of the safety related systems.

normal and reserve station service transformers are physically separated. The Unit 3 reserve sformer and Unit 3 normal station service transformer are also physically isolated from the r two and are fed from different positions in the switchyard than the Unit 2 reserve sformer. When the Unit 3 RSST is out of service, the Unit 3 NSST connection must be ited as the Unit 2 alternate off site source. A single failure of breaker 13T in the 345 kV tchyard would cause simultaneous loss of both Unit 2 off site sources, and therefore breaker and associated disconnect switches must be maintained open when this situation exists.

capacity and capability of the Unit 2 immediate off site source is unaffected by this action.

interconnecting 4160 volt crosstie between Unit 3 and Unit 2 bus 24E (A5) provides an rnate power source from Unit 3 reserve station service transformer or the Unit 3 normal ion service transformer (backfeeding).

24A (A1) and 24B (A2) 4160 volt buses supply loads required for normal operations while (A3) and 24D (A4) provide power to vital equipment including vital 480 volt AC load ters necessary for emergency shutdown or for incident conditions. Buses 24C (A3) and 24D

) serve redundant systems. The vital auxiliaries supplied from either bus are sufficient under onditions to provide safety feature action or to safely shut down the plant.

4.2 Tests and Inspections 6900 and 4160 volt circuits and associated devices are given operational checks while vidual equipment is shut down or not in service. Circuit breakers are withdrawn individually he test position and their functions tested. The preventive maintenance program for switchgear kers and protective relays is performed in accordance with Maintenance Procedures, based on ustry, regulatory and vendor recommendations.

figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

1 DESIGN BASES 1.1 Functional Requirements provide a reliable onsite source of auxiliary power if the preferred source is lost, the unit has onsite emergency generators. They are redundant, independent and separate, and are used for urpose other than that described. Each is connected to a 4160 volt emergency bus as shown in ure 8.2-1.

1.2 Design Criteria emergency generators and their associated devices are designed, built, and tested in ordance with Section 5.2.4 of IEEE Standard 308 1971, Safety Guides 6 and 9, and Criteria 1,

, 17 and 18 of Appendix A of 10 CFR Part 50. Seismic criteria are defined in Sections 5.8.1 5.8.1.1 of this report.

2 SYSTEM DESCRIPTION 2.1 System o physically and electrically separate, quick starting, skid-mounted diesel generators are vided. Each diesel generator set has the capability to initiate the engineered safety features F) in rapid succession, and to supply continuously the sum of the loads needed to be powered ny one time for a loss-of-coolant accident (LOCA). Each diesel generator is rated as follows:

2750 kw Continuous 3000 kw 2000 hours0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br /> 3250 kw 300 hours0.00347 days <br />0.0833 hours <br />4.960317e-4 weeks <br />1.1415e-4 months <br /> predicted loads listed in Tables 8.3-2 and 8.3-3 indicate that the continuous rating is not eeded.

no time during the loading sequence will the frequency and voltage decrease to less than 95 ent of nominal and 75 percent of nominal, respectively. During recovery from transients sed by step load increases or resulting from the disconnection of the largest single load, the ed of the diesel generator will not exceed rated speed plus 75 percent of the difference between d speed (900 rpm) and the overspeed trip setpoint (value in the range of 1008 rpm to 1053

). Voltage is restored to within 10 percent of rated voltage and frequency is restored to within percent of 60 hertz in less than 40 percent of each load sequence time interval.

adequacy of each diesel generator to perform its functions within the guidelines of Safety de 9 has been demonstrated by preoperational tests.

a. Loss of one redundant load group (AC or DC) will not prevent the minimum safety functions from being performed.

b. Each vital AC load group can be connected to the preferred (off site) power source, or to a standby (on site) power source consisting of a diesel generator. Neither standby source can be automatically connected to any load group except the one it is normally associated with.

c. The two standby power sources cannot be automatically paralleled with each other nor with the power system.

d. One load group cannot be automatically connected to another load group.

e. Loads cannot be automatically transferred between the redundant standby power sources.

f. 4160 Volt bus A5 (see Figure 8.2-1) can be manually tied to either standby power source but only under the restrictions described in Sections 8.2.2.2 and 8.2.3.3.

2.2 Components h unit consists of a 12 cylinder 900 rpm opposed piston Fairbanks Morse diesel engine, a e 966-40 generator, a high-speed solid state exciter-regulator unit, and associated control and iliary equipment. The unit has a continuous rating of 2750 kW, defined as 8760 hours0.101 days <br />2.433 hours <br />0.0145 weeks <br />0.00333 months <br /> of ration a year with an availability equal to or greater than 95 percent. This assures the ortunity for maintenance of the offload unit during post-accident operation.

units can be started by injecting compressed air into every other cylinder between the osed pistons, but for increased reliability in starting, compressed air is injected into every nder. The starting air system is shown on Figure 8.3-5. To further ensure starting reliability, following features are incorporated in each diesel generator unit:

a. Two air flasks are provided, each having sufficient capacity for a minimum of three starts. Their characteristics are as follows:

Normal operating pressure: 150 psi (min) to 230 psi (max)

Tank design pressure: 250 psi Design Code: American Society of Mechanical Engineers (ASME) VIII (1971)

b. The air flask valving is so designed that a rupture of one flask will not depressurize the other nor affect its capability to start the engine.

c. Both the lube oil and jacket water systems are provided with stay warm heaters and circulating pumps to maintain each unit at an elevated temperature to facilitate starting. An alarm alerts the operator if the heat fails.

recharging depleted flasks in one-half hour. The depleted flask pressure is considered at 150 psig since this corresponds to the pressure in the flask after three successive starts.

e. A DC motor-driven backup starting air compressor is provided for each diesel unit, manually operated or automatically controlled on flask pressure and supplied from the 125 volt DC vital system. It is annunciated when started.

f. An activated alumina desiccant air dryer, an oil coalescing prefilter, and a particulate after filter are provided in each line between the starting air compressor header discharge and the starting air flasks to provide clean dry air. The dryer is sized to accommodate the flow of both air compressors operating simultaneously.

g. The diesel engine lube oil system is so designed that the unit may be started from the main control board without priming the lube oil system.

cket water cooler, Tubular Exchange Manufacturing Association (TEMA) R shell and tube e, is provided for each emergency diesel generator. Cooling water is circulated in a closed loop ugh the diesel engine cooling water passages and the shell side of the cooler by an engine-en jacket coolant pump. An electric motor-driven standby jacket coolant pump and a jacket lant heater are provided to keep the cooling water heated while the diesel engine is not rating. The jacket cooling water system is shown on Figure 8.3-5. The cooling medium ing through the tube side of the jacket water cooler is supplied by the service water system is shown on Figure 9.7-1. The engines are capable of operating for approximately three utes at full load without cooling water supply. This provides sufficient time for the initiation low in the service water system by pumps connected to the emergency bus. In an emergency, n service water is not available, one emergency diesel may be cooled with fire water cross-nected to the service water system from valve 2-FIRE-258.

h diesel generator, its piping, and its auxiliaries are housed in its own Class I structure within auxiliary building. Ventilation, emergency lighting, and fire protection are provided. The tilating system is described in Section 9.9.12, and the fire protection is covered in tion 9.10.

sel fuel oil for the emergency diesel generators (EDGs) is stored in a 25,000 gallon proximate capacity) above ground diesel oil storage tank (T - 148). The fuel oil is transferred m the storage tank by two 25 gpm diesel fuel oil transfer pumps to the two 13,500 gallon proximate capacity), Class I, diesel oil supply tanks (T - 48A and T - 48B) which are located in structure that houses the associate EDG. A minimum of 12,000 gallons of fuel oil is stored in h above ground diesel oil supply tank. The piping is arranged such that normally one diesel oil transfer pump supplies diesel fuel oil to one diesel oil supply tank. However, there is an rconnection in the supply piping with a locked closed valve so that each transfer pump can ply diesel fuel oil to either supply tank. Diesel fuel oil is transferred by gravity from the supply to the engine-driven diesel fuel oil pump which supplies fuel oil to the diesel engine. The ng is arranged such that normally one supply tank provides diesel fuel oil to one EDG.

h diesel oil supply tank is maintained at a level above the required Technical Specification ume by operation of the respective diesel oil transfer pump. Both diesel oil transfer pumps take ction from the above ground diesel oil storage tank.

volume of fuel oil is not expected to vary during normal plant operation because the diesel erators are in standby. When the EDGs are running, diesel oil supply tank level will go down l automatic makeup from the diesel oil storage tank occurs. Each diesel oil transfer pump is trolled by a level switch which is set above the required Technical Specification volume.

required Technical Specification volume in the diesel oil supply tanks (T-48A and T-48B) provide sufficient fuel oil for two EDGs to operate at 2750 KW for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, and then one G to continue operation at 2750 KW for a total of approximately 3.5 days, assuming the two s are cross-connected after securing one EDG. An EDG run time of approximately 3.5 days vides a significant margin of time for replenishment of EDG fuel oil. Replenishment can be omplished from the non-safety related above ground diesel oil storage tank or offsite sources.

nonseismic above ground diesel oil storage tank provides the normal makeup path for fuel oil he fuel oil supply tanks. It contains fuel oil which is fully qualified and tested regularly.

east one diesel oil transfer pump will be available to supply fuel oil from the storage tank to diesel oil supply tanks, since the pumps are supplied from vital power sources. If the volume uel oil in the above ground diesel oil storage tank is taken into consideration, the one aining EDG will be able to continue operation at 2750 KW for an additional 3.5 days. This increase the total time one EDG will be able to operate to approximately 7 days.

seismic event occurs, the fuel oil in the above ground diesel oil storage tank cannot be relied n, because the above ground diesel oil storage tank is not seismically qualified. However, enishment of fuel oil could be accomplished via an offsite source.

required Technical Specification volume of 12,000 gallons in each diesel oil supply tank (T-and T-48B) is verified by the associated Technical Specification Surveillance Requirement.

required volume of fuel oil in the above ground diesel oil storage tank is 18,106 gallons ich include EDG frequency variation effects) plus a small volume increase to compensate for sable fuel due to instrument inaccuracy and suction pipe stub height, is not required by hnical Specifications. It is required by the Technical Requirements Manual and is verified by a ilar surveillance requirement. Also, the above ground diesel oil storage tank low level alarm is above this required volume. The associated alarm response procedure provides the necessary dance to restore the required above ground tank volume.

only necessary to maintain the required volume in the above ground diesel oil storage tank n the plant is operating in Modes 1 through 4. When the plant is in Mode 5 or below, the ected EDG loading will be significantly below rated load. Therefore, the Technical cification requirement for diesel fuel oil will provide reasonable assurance that sufficient time be available to obtain diesel fuel oil from an offsite source, if the above ground tank is not ilable.

luation of the need to order additional fuel from offsite sources within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> following a CA and LNP. The Emergency Plan procedures also require the Technical Support Center staff rovide load shedding recommendations within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of a LOCA and LNP. These load dding recommendations may include securing one EDG, cross connecting the two diesel oil ply tanks, and securing any electrical loads not needed to support plant recovery. The specific mmendations will vary depending on the situation, and will be developed within the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> e period. This time is sufficient to allow the Technical Support Center staff to develop the cific load shedding recommendations, and will allow an evaluation of the likelihood of fuel oil very to Millstone Unit Number 2. If fuel oil delivery is imminent, load shedding will not be essary.

EDG fuel oil system is shown on Figure 8.3-4. A failure mode analysis of the EDG fuel oil em is given in Table 8.3-1.

h diesel engine is provided with a lubrication system which circulates lube oil through a filter, ooler, a strainer, and then through the diesel engine by means of an engine-driven lube oil

p. An electric motor driven pre-lube pump is provided to be used for lubricating the engine ore it is manually started.

electric motor-driven standby lube oil pump and lube oil heater are provided to keep the lube heated while the diesel engine is not operating. The diesel lube oil system is shown on ure 8.3-5.

h diesel generator is tied to a 4160 volt emergency bus through a circuit breaker having vision for tripping as noted in Section 8.3.4.1. When the 4160 volt system is fed exclusively m the emergency diesel generators, the system ground is provided by a resistor loaded ribution transformer between each diesel generator neutral and ground. This grounding device ts ground current to one (1) ampere.

mic calculations for the diesel generator components were completed by the Fairbanks Morse er Systems Division of Colt Industries on July 26, 1972. These calculations were made for following eight items that were judged essential for continuous operation of the diesel erator:

Engine-generator skid assembly Heat exchanger stack assembly Lube oil filter Lube oil strainer Jacket water expansion tank Air compressor skid assembly Air receiver tank

tified calculations have been submitted and independently verified, showing that the diesel erating unit and its accessories meet the seismic requirements as elsewhere defined for this ect.

a later date, a mathematical analysis was made of the overspeed governor and shutdown em, similar to the calculations for the above listed assemblies. This analysis showed that this mbly meets the seismic requirements with a safety factor of 2.3.

3 SYSTEM OPERATION 3.1 Emergency Operation discussed in Section 7.3, the diesel generator associated with a 4160 volt AC emergency bus ives an automatic start signal under either of the following conditions:

a. ESAS Level 1 Undervoltage Actuation from the associated 4160 volt AC emergency bus

b. An ESAS Safety Injection Actuation Signal (SIAS) generator field is automatically flashed by DC from the 125 volt DC vital system when the reaches 250 rpm. Within 15 seconds of the start signal, the diesel generator accelerates to 90 ent or greater of rated speed and 97 percent or greater of rated voltage.

loss of voltage occurs on a 4160 volt AC emergency bus (with or without a concurrent SIAS),

following items occur:

a. The tie between the applicable buses (bus 24A (A1) - bus 24C (A3) or bus 24B (A2) - bus 24D (A4)) and the feeder applicable breaker from the reserve station service transformer are tripped.

b. All load feeder breakers on the emergency bus except small permanently connected loads are tripped.

c. The diesel generator breaker is automatically closed.

d. The closure of the diesel generator breaker starts a load sequencer that closes load feeder breakers in discrete steps. During the application of load steps, the minimum generator voltage and frequency and the recovery time to within 10% of nominal voltage and 2% of nominal frequency are within Safety Guide 9 requirements.

SIAS occurs with no concurrent loss of voltage on a 4160 volt AC emergency bus, then the esponding diesel generator starts but does not load. Consequently, if SIAS occurs with no

ogic diagram outlining the operation of the diesel generator and its auxiliaries is shown in ure 8.3-1, and the details of the control circuitry are shown in Figure 8.3-2. The load uencers are located in the ESAS actuation cabinet, and their operation is fully described in tion 7.3.

les 8.3-2 and 8.3-3 provide a breakdown of the automatic loading sequence for EDG A and B, ectively. The B pumps on the A5 swing bus are swing pumps and can be powered from ility Z1 (bus A3) or Facility Z2 (bus A4). The A5 swing bus can only be aligned to one facility time. When the A5 bus is aligned to a facility, that facilitys ESF signal will sequence the ropriate B pump into operation if the pump breaker is not in pull-to-lock or the breaker is racked-down. By procedure, the B pump(s) are made available for service only if their esponding A or C pump(s) are not available. Additional loads, such as the instrument air pressor or auxiliary feedwater (AF) pump, may be added by operator control.

al required loads for a LOCA with only one diesel operating, as shown in Tables 8.3-2 and 8.3-ave been conservatively estimated. The values of brake horsepower (bhp) for large motors er 100 hp) are based on the maximum operating requirements of the driven equipment for all des of operation. When converting horsepower to kilowatts for these motors, the actual motor ciencies are used. Equipment loads for motors rated 100 hp and less are based on the motor load rating and motor efficiency values which are typical for the motor size and type are used.

tery charger load requirements are based on the maximum calculated output requirement.

nsformer loads for supplying low voltage, instrumentation, and emergency lighting loads are percent of the transformer full load rating, without application of a factor for diversity.

mand factors are applied for specific loads in cases where operation is controlled by process ditions, such as temperature, pressure or level.

3.2 Abnormal Operation usual mode of operation of the onsite emergency power system is for both diesels to operate, pendently supplying emergency buses A3 and A4. However, if only one diesel will start, its sequencer will operate as described in the preceding section.

4 AVAILABILITY AND RELIABILITY 4.1 Special Features diesel generator units are physically isolated and their feeders are run separately. The engines uire no outside power for starting other than 125 volt DC for control logic, field flashing, and ker control. One of the two station vital batteries supplies 125 volt DC to one diesel with the r battery supplying the second diesel via separated cable routings.

starting air solenoid valves are fail-safe. That is, a loss of DC voltage or other de-energization ither of the solenoids admits starting air to the engine.

rating experience has shown that a diesel which does not start within ten seconds is not likely tart at all. Therefore, the start is interrupted to conserve the air supply for later start attempts, sequent to a system checkout and correction.

h of the following alarm conditions of an emergency diesel generator (EDG) have a esponding annunciator in the main control room but does not have an annunciator on the local trol panel of the applicable EDG:

Diesel generator breaker trouble Diesel automatic start Diesel SIAS start Diesel generator ready to load Exciter not reset Diesel control switch in maintenance position Diesel generator auto voltage regulator not set at 4160 following alarm condition of an EDG has a specific annunciator in the main control room and plicate annunciator on the applicable local control panel:

• Generator differential current h of the following alarm conditions of an EDG has: (1) either a specific or shared annunciator he applicable local control panel, and (2) a shared common annunciator in the main control m, Diesel Generator U12 (or U13) Trouble:

• Lube oil pressure - low

• Engine overspeed Loss of unit 4160 volt auxiliary power Lube oil temperature - high - low Lube oil level - low Jacket water temperature - high - low Service water coolant - low flow Starting air pressure - low DC air compressor - start Engine start failure Fuel oil supply tank - low Generator underfrequency Generator undervoltage

Generator neutral ground fault Generator overvoltage Generator bearing temperature - high Jacket water level - low Fuel oil supply valve - shut Generator stator temperature - high Loss of 480 volt auxiliary power Loss of 125 volt DC control power Pre-lube pump running Key lock switch in slow start Jacket water pressure - low (results in trip only when on test)

Crankcase pressure - high (results in trip only when on test)

Fuel oil pressure - low (results in trip only when on test)

Reverse power flow (results in trip only when on test)

Instantaneous overcurrent (results in trip only when on test)

Core balance ground fault (results in trip only when on test)

Any auxiliary control switch not in automatic position three devices marked

• above are the only shutdown functions permitted during an rgency start. These three conditions, if allowed to continue, would rapidly result in the loss of diesel generator. Hence, it is advantageous to remove it from service when the condition is sensed and thereby minimize damage to the engine or the generator. These trip devices are all sidered essential as noted below:

a. Low Lube Oil Pressure This shutdown functions upon coincidence of two out of three signals when the normal pressure of over 20 psi has dropped to 16 psi or two out of two signals when normal pressure has dropped to 18 psi. The engine manufacturer considers this to be an essential feature.

b. Engine Overspeed A centrifugal governor shuts down the engine at about 116% of rate speed. Full load rejection can be made without actuating this trip.

c. Generator Differential Current This feature protects the generator in the event of an internal fault.

ng surveillance testing and during emergency operation. The operator has the facility to reset close the EDG breaker should the fault clear or be isolated by a load breaker.

single failure can prevent both diesel generators from functioning. Surveillance rumentation will warn the operator during normal station operation of detectable inadequacies ailures which could lead to loss of function of the diesel generator and its power supply em. Components whose correct functioning can be verified only during operation of the diesel erator system will be tested periodically. An analysis of the effects of a single failure within instrumentation or controls of one of the diesel generators under an emergency condition is n in the following:

Signal or Component Malfunction Comments and Consequences dervoltage signal or Failure to detect Undervoltage sensors are redundant tential transformer on undervoltage and arranged in two-out-of-four logic 60 volt bus so single failure will have no consequences on operation of system.

s clearing circuitry Failure to operate Failure of bus clearing circuitry will lock out corresponding diesel generator feeder breaker. However, other diesel generator will not be affected; sufficient emergency equipment will remain in operation for safe shutdown.

esel engine or generator Failure to start engine Failure of one diesel engine to start or ntrol circuitry or to close generator generator breaker to close will leave breaker one completely redundant emergency system available for operation.

fferential protection Relay and/or contact Will result in tripping diesel generator; ay failure other diesel generator will carry gine overspeed redundant load, so will not affect w lube oil pressure safety.

ltage Restraint Relay and/or contact Will result in tripping the diesel ercurrent Relay failure breaker. Indication of the fault will be provided by the DIESEL GEN 12U 913U) BKR CLOSING CIRCUIT BLOCKED alarm and DIESL GEN 12U (13U) BKR TRIP. If the fault has cleared or has been isolated the operator can attempt to reset the condition and close the breaker, otherwise, the other diesel will carry the redundant load and so safety will not be affected.

ound fault relay Relay and/or contact Indication of fault will be provided on failure local annunciator with common (diesel generator trouble) alarm in main control room. Relay and/or contact failure will initiate false alarm but will have no effect on diesel generator operation.

ad sequencer Failure to operate in Worst case will result in tripping proper sequence corresponding diesel generator. Other diesel generator will not be affected, and sufficient emergency equipment will remain in operation for safe shutdown or other emergency action.

ergency bus tie breakers Failure of electrical Mechanical interlocks will prevent interlocks to prevent paralleling of two main 4160 volt closure of tie breaker emergency buses.

C supply Loss of one station Could not open supply breakers nor battery or its shed loads; diesel generator voltage distribution system would not be established due to lack of concurrent with loss of field flashing; generator breaker would off site power not close. Because of complete separation of redundant DC supplies, other diesel generator would function as required for safe shutdown or other emergency action.

4.2 Tests and Inspections sel generator tests are designed to demonstrate that the diesel generators will provide adequate er for the operation of the equipment. They also assure that the emergency generator control

quent tests are made to identify and correct any mechanical or electrical deficiency before it result in a system failure. The fuel supply and starting circuits and controls are continuously nitored and faults are annunciated. An abnormal condition in these systems will be signaled hout having to place the diesel generators on test (see Figure 8.3-2).

verify that the emergency power system will properly respond within the required time limit n required, the following tests are performed:

a. EDG load testing, load rejection testing and start time testing is performed in accordance with Technical Specifications requirements.

b. Demonstration of the automatic sequencing equipment during normal unit operation. For details, see Section 7.3.

Monthly Surveillance Testing To minimize the mechanical stress and wear on the diesel engine, each diesel engine will be started in slow speed using the Mechanical Governor.

During the slow start procedure, a key lock switch is used to block certain full speed function (i.e., excitation, jacket water low pressure) from occurring during reduced speed.

The protective devices that function to shut down the diesel generator are checked periodically for their trip setpoints. For the overspeed device, the diesel can be forced to increase in speed until trip occurs. Crankcase and lube oil pressure switches are disconnected and an outside pressure source applied until the trips occur. Periodically, the protective relays are inspected and their setpoints checked.

A sample of the fuel oil in the above ground storage tank will be taken manually and analyzed periodically.

ision 3806/30/20 DETRIMENTAL CORRECTIVE RESULTANT PONENT FAILURE MODE MONITOR EFFECT ACTION STATUS il supply tanks Rupture of one tank Low level alarm Loss of fuel oil Isolate supply tank; Redundant diesel 48B open valve between supply tank available lines to engines er to diesel Pipe break Low level alarm Loss of fuel oil and Isolate break and Redundant diesel one diesel generator repair generator in service (1) en fuel oil pump Mechanical failure Low pressure Loss of one diesel Isolate pump and Redundant diesel ine) alarm generator repair generator in service (1) ators H7A & Loss of fuel oil for Low pressure Loss of one diesel Isolate diesel Redundant diesel other reason alarm generator generator generator in service (1)

MPS-2 FSAR l generator has adequate capacity for emergency conditions.

8.3-13

ision 3806/30/20 CONNECTED LOADS Running KW for Loads Powered from EDG A for LOCA with LNP Automatically Started Loads Post Motor Actual Load LOCA escription Rated HP BHP 0 Sec 2 Sec 8 Sec 14 Sec 20 Sec Loads rger X X ble Losses X X ated Valves X Lighting X X rmers X X PS X X oom Air X X g

us Connected X X MPS-2 FSAR SEQUENCE 1 Running KW for Loads Powered from EDG A for LOCA with LNP Motor Actual Automatically Started Loads Post LOCA scription Rated HP Load BHP 0 Sec 2 Sec 8 Sec 14 Sec 20 Sec Loads er 450 426 365 365 re Safety Injection 400 460 388 388 t Air X X n Fans (2) Scenario 8.3-14

ision 3806/30/20 SEQUENCE 2 Running KW for Loads Powered from EDG A for LOCA with LNP Automatically Started Loads Motor Actual Post LOCA Description Rated HP Load BHP 0 Sec 2 Sec 8 Sec 14 Sec 20 Sec Loads W 350 315 265 265 ng (2) 200 Scenario 388 182 SEQUENCE 3 Running KW for Loads Powered from EDG A for LOCA with LNP Automatically Started Loads Motor Actual Post LOCA Description Rated HP Load BHP 0 Sec 2 Sec 8 Sec 14 Sec 20 Sec Loads ressure Safety Injection 400 380 325 nment Spray (2) 250 230 195 195 MPS-2 FSAR Related HVAC X X SEQUENCE 4 Running KW for Loads Powered from EDG A for LOCA with LNP Automatically Started Loads Motor Actual Load Post LOCA Description Rated HP BHP 0 Sec 2 Sec 8 Sec 14 Sec 20 Sec Loads ary Feedwater 350 360 306 268 8.3-15 Related HVAC X X

ision 3806/30/20 MANUAL LOADS Running KW for Loads Powered from EDG A for LOCA with LNP Automatically Started Loads Motor Actual Load Post LOCA Description Rated HP BHP 0 Sec 2 Sec 8 Sec 14 Sec 20 Sec Loads Fuel Pool Cooling X gen Recombiner ment Air Compressor X nment Sample X cident Recirculation Fan X ncy Diesel Generator (EDG) running load is less than 2750 KW at all steps, this is the continuous rating of the EDG.

3 minutes following auto sequencing, Motor Operated Valve (MOV) loads will have reached their required position.

MPS-2 FSAR 10 minutes following auto sequence, auxiliary feedwater pump load will be at normal LOCA flow.

iliary feedwater pump BHP value is different for pump run-out (360 BHP) and required flow (315 BHP).

d modeled with EDG at Technical Specifications maximum Hz frequency value.

8.3-16

ision 3806/30/20 CONNECTED LOADS Running KW for Loads Powered from EDG A for LOCA with LNP Automatically Started Loads Post Motor Actual LOCA Description Rated HP Load BHP 0 Sec 2 Sec 8 Sec 14 Sec 20 Sec Loads rger X X ad Center Transformer X X ated Valves X Lighting X X rmers X X PS X X oom Air Conditioning X X us Connected X X MPS-2 FSAR SEQUENCE 1 Running KW for Loads Powered from EDG A for LOCA with LNP Automatically Started Loads Post Motor Actual Load LOCA escription Rated HP BHP 0 Sec 2 Sec 8 Sec 14 Sec 20 Sec Loads er 450 426 365 365 re Safety Injection 400 460 388 388 t Air Recirculation 75 Scenario X X 8.3-17

ision 3806/30/20 SEQUENCE 2 Running KW for Loads Powered from EDG A for LOCA with LNP Automatically Started Loads Motor Actual Post LOCA escription Rated HP Load BHP 0 Sec 2 Sec 8 Sec 14 Sec 20 Sec Loads 350 315 265 265

) 200 Scenario 388 182

2) 50 X X SEQUENCE 3 Running KW for Loads Powered from EDG A for LOCA with LNP Motor Actual Automatically Started Loads Post LOCA escription Rated HP Load BHP 0 Sec 2 Sec 8 Sec 14 Sec 20 Sec Loads e Safety Injection 400 380 325 t Spray (2) 250 230 195 195 MPS-2 FSAR ed HVAC X X SEQUENCE 4 Running KW for Loads Powered from EDG A for LOCA with LNP Motor Actual Automatically Started Loads Post LOCA escription Rated HP Load BHP 0 Sec 2 Sec 8 Sec 14 Sec 20 Sec Loads edwater 350 360 306 268 8.3-18 ed HVAC X X

ision 3806/30/20 MANUAL LOADS Running KW for Loads Powered from EDG A for LOCA with LNP Automatically Started Loads Motor Actual Post LOCA escription Rated HP Load BHP 0 Sec 2 Sec 8 Sec 14 Sec 20 Sec Loads ool Cooling X ecombiner Air Compressor X iliaries X t Sample X t Recirculation Fan X iesel Generator (EDG) load is less than 2750 KW, this is the continuous rating of the EDG.

MPS-2 FSAR nutes following auto sequencing, Motor Operated Valve (MOV) loads will have reached their required position.

inutes following auto sequence, auxiliary feedwater pump load will be at normal LOCA flow.

feedwater pump BHP value is different for pump run-out (360 BHP) and required flow (315 BHP).

8.3-19

figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

CONDENSATE AND HEATER INDEX (SHEETS 1) figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

CONDENSATE AND HEATER INDEX (SHEET 2) figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

CONDENSATE AND HEATER INDEX (SHEET 3) figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

1 DESIGN BASES 1.1 Functional Requirements 480 volt system provides power for unit auxiliary loads below 250 horsepower. Those iliaries required for a safe shutdown of the unit or for maintaining it in hot standby condition served by emergency load centers and emergency motor control centers. These emergency volt sources feed battery chargers for the DC system and regulating transformers for 120 volt instrumentation.

1.2 Design Criteria 480 volt system, including emergency load centers and emergency motor control centers, is gned, built and tested in accordance with Sections 4 and 5.2 of the IEEE Standard 308-1971, eria 1, 2, 3, 4, 17, and 18 of Appendix A of 10 CFR Part 50, and Safety Guide 6.

of the 480 volt equipment in safety-related services is designed for the seismic conditions cribed in Sections 5.8.1 and 5.8.1.1.

2 SYSTEM DESCRIPTION 2.1 System 480 volt system shown in Figure 8.2-1 consists of six buses; two double-ended and two le-ended load centers. The double-ended load centers supply normal station loads. Each sists of two transformers and two bus sections with a tie breaker. Each transformer is nected to a different 4160 volt bus and is sized to support the loads of both 480 volt bus ions for maintenance purposes. The double-ended load center feeder and tie breakers are rlocked to prevent simultaneous connection of both 4160 volt sources to a single bus. The rlock can be defeated through the use of sync selector switches which permit momentary lleling of load center 22A with 22B or load center 22C with 22D across the respective tie kers 22A-1T-2 or 22C-1T-2. The sequence allows: (1) paralleling across and closing of the tie ker immediately followed by the automatic opening of one of the selected feeder breakers, or paralleling across and closing of a selected feeder breaker immediately followed by the matic opening of the associated tie breaker. The two single-ended load centers (B5 and B6) h consist of a single transformer and bus section and supply loads necessary for safe shutdown ost-incident conditions.

ddition, a portable generator connection point has been provided to back feed bus 22F. This nection is a defense-in-depth feature that is available for coping with an extended loss of AC er (ELAP) event. The connection is shown on Figure 8.2-1. Main Single Line Diagram.

tor control centers, located throughout the unit, are fed from these load centers. Four of these considered emergency motor control centers (B51, B52, B61, B62), and are fed from the

mal station lighting is provided by 480-208/120 volt and 480-277 volt transformers located ughout the plant. Power for lighting of critical operating areas, such as the control room, el generator rooms, DC switchgear rooms, emergency shutdown panels and refueling areas is plied as described above but has additional backup lighting panels fed from the emergency or control centers.

a loss of all AC sources, the life safety lighting requirements for egress are satisfied by the hour rated, self-contained battery units installed throughout the station. In addition, the MP2 endix R Compliance Report, Section 6.3 credits 8-hour rated battery backed emergency ting units (ELU's) and security lighting, which illuminate outdoor access and egress routes, to e with a design basis fire. The security lighting power supply is backed by a security diesel erator. These Appendix R lighting fixtures (8-hour rated, self-contained battery units, and the urity lighting) are credited by the Station Blackout Safe Shutdown Scenario. The 1.5-hour d, life safety battery units provide additional portable emergency lighting for ingress / egress plant areas during a SBO Event.

2.2 Components 480 volt power supply and utilization equipment in safety-related services is housed in Class I ctures. These spaces are equipped with smoke and fire detection systems and portable fire nguishers.

480 volt load centers are free standing, indoor type with dripproof enclosures containing wout-type air circuit breakers, motor starters, and associated relays, instruments and fuses.

ir rating is as follows:

nsformers Transformers 1500 kVA (AA), 2000 kVA (FA)

Temperature rise 80°C (40°C ambient)

Impedance 7.59 to 8.7%

2000 amp continuous uit Breakers Main incoming feeders 3000 amp continuous 65,000 amp interrupting (without instantaneous trip)

MCC feeders and ties 42,000 amp interrupting (without instantaneous trip)

Load feeders 600 amp continuous 30,000 amp interrupting (with instantaneous trip)

Emergency MCC - short and long time elements on all phases Mag-jack M-G - instantaneous on all phases; long-time element on two phases Other feeders - instantaneous and long time elements on all phases al 480V buses 22E & 22F are equipped with class 1E voltage monitoring devices. These ices initiate an alarm in the control room if the devices respective bus voltage exceeds 516 C. This warns operators to correct the situation using plant procedures to minimize the rvoltage conditions which increase the potential for long-term equipment degradation.

est report dated July 21, 1970, from General Electric, describes the vibration and shock tests n to a prototype of this switchgear. The seismic qualification of the transformers was verified a mathematical analysis. A summary of the results of the 480 volt switchgear tests is given w:

a. GE-type AKD-5 switchgear has been vibration tested in each of the three directions at 0.5 g over the frequency spectrum of 5 to 500 hertz.

b. AKD-5 switchgear has been shock tested to 40 g on a Navy medium-weight shock machine.

c. GE-types AK-50 and AK-25 breakers have been vibration tested in each of the three directions at 0.5 g over the frequency spectrum of 5 to 500 hertz.

d. AK-50 and AK-25 breakers remained operative during shock at accelerations up to 15 g on a Navy medium-weight shock machine.

e. The AK-50 breaker has been vibration tested without loss of function during vibration at its lowest resonant frequency of 29 hertz at 5.0 g input.

f. The AK-25 breaker has been vibration tested without loss of function during vibration at its lowest resonant frequency of 44 hertz at 3.0 g input.

motor control centers are General Electric free standing types with dripproof indoor losures containing combination starters, molded case circuit breakers, individual starter trol transformers, and associated relays and fuses. Two Emergency Control Centers, B51 and

, are encapsulated in environmentally controlled enclosures due to their location in areas ch could be subject to a steam environment resulting from a high-energy line break. The ngs for the motor control centers are as follows:

Bus (main) 600 or 800 amp continuous (vertical) 300 amp continuous

rcurrent and motor overload protection are provided on each feeder as follows:

Thermal-magnetic circuit breaker Three thermal overload relays in each motor starter (except for MOV) ertification from General Electric, dated December 20, 1971, testifies that tests they made on ust 21, 1970, were on a prototype of the emergency motor control centers furnished for this ect. A summary of these tests is given.

a. The test article was swept in frequency from 5 to 500 hertz at a one-half octave per minute sweep rate at a constant 0.5 g input acceleration.

b. The equipment was vibrated in each of its three orthogonal axes; vertical, horizontal in-breadth, and horizontal fore and aft.

c. All vibration sweeps were made with a 480 volt AC, 60-hertz source connected to the control center main bus.

d. Vibration sweeps were made in two modes of functional status:

1. With each starter unit disconnect in the ON position but starter not energized.

2. With each starter energized.

e. The tests conducted indicate the equipment, as tested, is suitable for applications up to at least 0.5 g base input accelerations through a frequency band width from 5 to 500 hertz.

f. The resonant level of the equipment structure appears to be at 5 to 6 hertz, while component resonant levels are at higher frequencies.

g. Interchanging of starter units vertically within the equipment will not significantly alter the response of the individual components inasmuch as the structure is nonresonant at the frequencies at which components are resonant.

h. These tests indicate that the 7700 line motor control center is suitable to at least 0.5 g base input accelerations through a frequency band width from 5 to 500 hertz.

h of the two control element assembly drive power sustainers is connected to a 480 volt rgency load center. The control element assembly drive power sustainer system consists of ride-through flywheel motor generator sets. The motor generator sets have the ability to hold

only motors inside the containment required during a LOCA are those driving the tainment air recirculation and cooling fans and the post incident recirculation fans noted in tion 8.4.1.2. The suitability of these motors to meet the environmental and seismic shock uirements is presented in Sections 6.5.4.2 and 6.6.4.2, respectively.

3 SYSTEM OPERATION 3.1 Normal Operation mally, each emergency load center transformer is fed from a corresponding emergency 4160 bus, which in turn receives power from a station service transformer as shown in Figure 8.2-here is no way in which these two load centers can be tied together. Each of these load centers s two emergency motor control centers.

3.2 Emergency Operation er emergency conditions, there is no change in the mode of operation of these load centers motor control centers. The only changes are those associated with the means of supplying er to the 4160 volt emergency buses, as described in Sections 8.2 and 8.3.

4 AVAILABILITY AND RELIABILITY 4.1 Special Features load groups on each emergency load center and its associated motor control centers are undant to each other and separate. Hence, a complete failure of power, or failure of ponents on one channel does not affect the availability of services to care for a LOCA.

charging pump is fed from power source Z1 and one from Z2. The third charging pump can aligned with either a channel Z1 or channel Z2 source. Two power selector switches with trical and Kirk key interlocks prevent tying the two motor control center buses together, as wn in Figure 8.4-1. If one pump is out of service, the selector switches are positioned (under inistrative control) to feed the third pump from the power source redundant to that which is ing the operating pump. Thus, in case of an accident, two charging pumps are available, each from a separate and redundant power source.

noted in Section 8.2.3.3 and in Figure 8.2-1, the third service water pump is fed from 4160-bus A5, which can be energized from either a channel Z1 or Z2 source. The service water iner associated with this pump has a feeder from each of two 480 volt emergency motor trol centers fed from these two vital sources. Two power selector switches (under inistrative control) with electrical and Kirk key interlocks prevent tying the two motor control ter buses together, as shown in Figure 8.4-2. If the selector switches are not positioned to plete the supply circuit, an alarm is given on the main control board. Interlocking also assures

ays available, each with a separate and redundant power source.

tdown Cooling Suction Header Containment Isolation valve 2-SI-651 also has the capability eing supplied power from either Facility Z1 or Facility Z2. This valve is not an installed spare of emergency equipment as discussed in Section 8.2.3.3. The alternate power provides a ns to open 2-SI-651 post-LOCA for boron precipitation control and will not be utilized during mal plant operation. Therefore, this valve is not considered a Facility Z5 component. To vent placing the plant in an unanalyzed condition for separation concerns, the cross connection

-SI-651 to Facility Z2 is limited to boron precipitation control post-LOCA combined with a of power to MCC B51 or for testing purposes. Emergency operating procedures provide dance for aligning 2-SI-651 to its alternate power.

4.2 Tests and Inspections 480 volt circuit breakers, motor starters, and associated equipment are tested while individual ipment is shut down or not in service. Circuit breakers and starters are withdrawn individually their functions tested. Accidental grounds on the load center buses or feeders are monitored tinuously by ground detectors and are alarmed in the main control room.

d center transformers are periodically given an insulation resistance test either on line or ng a refueling outage in accordance with a preventive maintenance program.

figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

CROSSOVER SCHEME figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

1 DESIGN BASES 1.1 Functional Requirements tery power is needed for a variety of uses, such as trip and close of electrically operated uit breakers, certain solenoid operated valves, certain control systems, and devices used ng turbine coastdown. Through DC/AC inverters, the batteries also provide power to the tor protective system, engineered safety features actuation, and to vital instrumentation.

1.2 Design Criteria components of the battery system are designed, built, and tested in accordance with the uirements of:

Safety Guide 6 Section 5.3 of IEEE Standard 308, 1971, with the exception of the requirements for the frequencies of battery discharge tests (battery service tests) and battery charger performance tests. (These tests are required to be conducted in accordance with the Surveillance Frequency Control Program.)

Section 6.3.4 of IEEE 308, 1980 Criteria 1, 2, 3, 17, and 18 of Appendix A of 10 CFR Part 50 Section 4 of IEEE 279, 1971 IEEE 650, 1979 mic criteria are defined in Sections 5.8.1 and 5.8.1.1 of this report.

2 SYSTEM DESCRIPTION 2.1 System 25 volt DC supply system consisting of two isolated switchgear bus sections (with key rlocked tie breakers) and associated distribution panelboards is provided. Each of the two DC tchgear bus sections is supplied by a separate 60 cell battery and two 400 amp battery rgers, normally connected in parallel to form a single 800 amp charger. Figure 8.5-1, Sheet 1, strates this system. An additional battery/charger/switchgear combination is provided for vital loads associated with the turbine and its auxiliaries, and for backup of selected vital rument AC panels through DC/AC inverters. Figure 8.5-1 Sheet 2 illustrates this system.

ratings of the principal components of the main (vital) battery systems are as follows:

teries2 (C&D Type LCR-33)

Rating 8 hr (amp-hr) 2320 1 min (amp) 2240 Voltage, nominal (volts) 125 min 105 max 140 rgers2 pairs Capacity, individually (amp) 400 Capacity, total each pair (amp) 800 Voltage (volts, DC) 110-140 Regulation (%) +/-1.0 Ripple, max (%) 2.0 Current limit (%) 125 tchgear2 groups Circuit breaker s Continuous (amp) 1600 Interrupting (amp) 50,000 Bus Continuous (amp) 2000 eparate 125 volt battery system has been provided to supply power to the DC emergency oil ps associated with the main turbine and the turbine-driven feedwater pumps and to two arate nonvital DC/AC inverters for backup of the 120 VAC vital 1 and 2 instrument panels.

system consists of a 1500 amp-hr battery, two 200 ampere chargers, and a DC switchgear mbly that includes the required motor starters and 600 amp continuous, 25,000 amps rrupting air circuit breakers. A DC panelboard, fed from the turbine battery, supplies turbine erator control power.

ion battery rooms are in Class I structures and have continuous induced ventilation as cribed in Section 9.9.6.

cedure Number 543/0173/DB dated February 13, 1992, Revision A dated June 18, 1992. This program was performed on June 19, 1992, as documented in Test Report 42614-1.

test program consisted of single axis Resonance Search testing and triaxial Random ltifrequency testing. The specimen was instrumented with accelerometers, electrically ered, loaded and monitored as directed by Cyberex during the test program.

as demonstrated that the battery charger specimen possessed sufficient structural integrity to hstand, without compromise of structure or monitored functions, the prescribed simulated mic environment.

h station battery is contained in two 2-step free standing racks bolted to the floor. In the mic calculations, the lower step was omitted in calculations of natural frequency and resisting tional forces of top step cells were neglected. The system is symmetric about the mid-frame.

culations included the determination of stresses due to horizontal motion in short direction, zontal motion in longitudinal direction, vertical motion, and side rail stresses due to short ion. All checked out to indicate a conservative design.

000A fused disconnect switch is used with each station battery. The fused disconnect switches seismically qualified using the GIP-2 methodology for resolution of USI-46 as discussed in ort Number 03-0240-1367, Revision 0, dated December 14, 1995.

o LCU-33 (1) battery cells were installed in a battery rack which was attached to the table of a ation machine. The specimens were vibrated between 3.5 and 19.5 Hz along each of the two ually perpendicular horizontal axes and the vertical axis simultaneously. Acceleration was lied at an angle of 36° from the horizontal. The two cells were connected in series and the put voltage monitored during the test. There was no evidence of electrical discontinuities or hanical damage during or as a result of these dynamic exposures.

3 SYSTEM OPERATION 3.1 Normal Operation 125 volt DC vital system shown in Figure 8.5-1, sheet 1, provides a reliable power and trol source for systems required for a safe shutdown and for post-incident operation. A typical ective scheme is shown in Figure 8.5-2, Reactor Trip Switchgear schematics.

The LCR-33 replacement cells are similar to the tested LCU-33 cells. See C&D Charter Power tems, Inc., Environmental and Seismic qualification Report Number QR 163409-01, dated y 24, 1995.

vent the paralleling of the two batteries but allow either battery to feed both buses, if necessary ng cold shutdown or refueling operations. While in this alignment (one battery connected to h buses, each battery is sized to supply the total connected vital loads for one hour without rger support. In all other plant modes of operation, each battery is sized to supply the most ere postulated load conditions on its associated bus for an eight-hour duty cycle. During mal operation, the 125V DC load is supplied from the battery chargers with the batteries ting on the 125V DC bus. On loss of AC power to the battery chargers, the DC load is plied from the battery. Power is available to these DC loads for a period of 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />. After urs, it is assumed that AC power is restored to the chargers either from the system or the rgency generators.

h 400 amp of charger is able to recharge a fully discharged battery in less than 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> while porting the maximum continuous load of that battery. (A fully discharged battery is a battery re the cells are discharged to 1.75 volts per cell). Each battery/charger combination feeds its independent and separate distribution channels via a main DC switchgear assembly. Each tchgear bus supplies two independent and physically separated 125 volt DC distribution elboards for vital loads, two 125 volt DC panelboards for nonvital loads, and two separate volt DC/120 volt AC static inverters for vital instrumentation. Each of the two inverter puts is connected to an independent and physically separated 120 volt AC panelboard. Thus, separate DC feeders and two separate AC feeders (via the inverters) are available from each ery for distribution within the plant.

he event of the loss of all sources of AC, minimal lighting requirements for egress per Life ety Code (NFPA) are satisfied by 1.5-hour rated, self-contained automatically charged battery k, lighting units.

3.2 Emergency Conditions re is no change in the mode of operation of the battery system during emergency conditions ept for the loads associated with loss of offsite power. On loss of AC power, vital battery loads ude breaker tripping and closing circuits, continuous control circuits, inverters, EDG air pressors and EDG field flash current. The battery service test profile shown in Table 8.5-1 elopes the battery discharge current versus time profile for both vital batteries on loss of AC er.

4 AVAILABILITY AND RELIABILITY 4.1 Special Features h of the two 125 volt DC emergency power sources is equipped with the following rumentation in the control room to enable continual operator assessment of emergency power rce condition:

a. Direct current bus undervoltage alarm.

c. Bus current indication.

d. Charger malfunction alarm (including input AC undervoltage, output DC undervoltage and overvoltage, high temperature, low airflow, high and low output current).

e. Direct current bus voltage indication.

f. Direct current ground alarm.

undervoltage relay is designed specifically to monitor the charging supply for a station ery and to sound an alarm if this supply fails. The setting of the relay is above 125 volts, and equipment is capable of operating down to 95 volts.

125 volt switchgear circuit breakers have magnetic series trip elements for overcurrent ection as follows:

Battery charger - instantaneous, short-time and long-time elements Other feeders - short-time and long-time elements iliary spray charging header supply valve 2-CH-517 and Loop 1A charging header supply e 2-CH-519 have the capability of being supplied power from either Facility Z1 or Z2. These es are not an installed spare unit of emergency equipment as discussed in Section 8.2.3.3. The rnate power provides a means to open 2-CH-517 and close 2-CH-519 post-LOCA for boron ipitation control and will not be utilized during normal plant operations. Therefore, these es are not considered Facility Z5 components. To prevent placing the plant in an unanalyzed dition for separation concerns, the cross connection of 2-CH-517 and 2-CH-519 to Facility Z1 mited to boron precipitation control post-LOCA, coincident with a loss of normal power, bined with a loss of Facility Z2 DC power, or for testing purposes. Emergency operating cedures provide guidance for aligning 2-CH-517 and 2-CH-519 to their alternate power.

4.2 Tests and Inspections ensure battery functional capability and to assure detection of battery degradation, the owing tests and inspections are performed periodically:

a. Float voltage is measured.

b. Cells are checked for cracks or leakage.

c. The plates of cells are checked for buckling, discoloring, grid cracks and plate growth.

e. Voltage of each cell is measured.

f. Electrolyte level of each cell is checked, and all water additions are recorded.

g. Temperature and specific gravity of the electrolyte of a pilot cell are measured.

h. Battery charger alarms and battery charger voltages are checked.

i. Bottoms of cells are visually inspected for flaking buildup and for abnormal cell plate deterioration.

j. Periodically a battery charger AC supply breaker will be opened to verify the load-carrying ability of the battery. During this test an undervoltage annunciator will indicate that the battery chargers are out of service.

teries will deteriorate with time, but precipitous failure is extremely unlikely. The surveillance cified is that which has been demonstrated over the years to provide an indication of cell radation long before it fails. Battery replacement will be made when a capacity test indicates battery capacity is at or below 80 percent of the manufacturers rating.

Discharge Step Duration Nominal Test Current (DC Amperes) 1 0 to < 1 Minute 311 2 1 to < 29 Minutes 224 3 29 to < 30 Minutes 242 4 30 to < 120 Minutes 221 5 120 to < 479 Minutes 197 6 479 to < 480 Minutes 243

figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

CIRCUITRY (SHEET 1) figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

CIRCUITRY (SHEET 2) figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

CIRCUITRY (SHEET 3) figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

CIRCUITRY (SHEET 4) figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

CIRCUITRY (SHEET 5) figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

CIRCUITRY (SHEET 6) figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

CIRCUITRY (SHEET 7) figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

CIRCUITRY (SHEET 8) figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

CIRCUITRY (SHEET 9) figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

CIRCUITRY (SHEET 10A) figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

CIRCUITRY (SHEET 10B) figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

CIRCUITRY (SHEET 10C) figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

CIRCUITRY (SHEET 10D) figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

CIRCUITRY (SHEET 11) figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

CIRCUITRY (SHEET 12) figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

1 DESIGN BASES 1.1 Functional Requirements 120 volt AC instrument power for reactor protection, engineered safety features and vital rumentation is supplied by four physically isolated and electrically independent vital rument panels. Each vital instrument panel is powered by one of four physically isolated rters. Two inverters are powered by each of the two redundant batteries.

1.2 Design Criteria s power source is normally derived from the station battery system described in Section 8.5, ce the same criteria are met.

2 SYSTEM DESCRIPTION 2.1 System s special 120 volt AC power supply and distribution system is shown in Figure 8.5-1, Sheets 1

2. It consists of two separate and redundant systems composed of four essential buses for vital rumentation and control, and two regulated buses for nonvital instrumentation and control.

four vital AC buses are normally supplied from DC/AC static inverters. The 120-volt ulated AC instrument panelboards supply the nonvital instrumentation requirements.

h regulated panel is powered through a transfer switch from a normal or alternate source ch includes one Uninterruptible Power Supply (UPS) fed by a nonemergency motor control ter and one 480/208-120 volt regulating transformers fed by an emergency motor control ters. During normal operation, the transfer switch is in the normal position and power is fed m the normal MCC and UPS. Should this voltage drop to a predetermined low voltage oint, the transfer switch transfers to the alternate supply and power will be fed from the rnate MCC and regulating transformer.

ddition, portable generator connection points have been provided on 120VAC vital panels 20 and VA40. These connections are defense-in-depth features that are available for coping h an extended loss of AC power (ELAP) event. The connections are shown on Figure 8.5-1, ngle Line Diagram.

ddition, for increased flexibility during planned maintenance periods, the normal source UPS be supplied with an administratively key controlled source, an emergency MCC.

provide increased reliability, each of the four vital instrumentation panels has an alternate er supply via a zero break static transfer switch. Vital channels 1 and 2 are fed from

2.2 Components ddition to the battery system components described in Section 8.5.2.2, four DC/AC static rters with static transfer switches are required.

erters (INV2, INV4, INV6) are Cyberex, Inc. Pulse Width Modulation (PWM) style inverters Inverters (INV1, INV3, INV5) are Ametek Ferroresonant style inverters.

Inverter characteristics are as follows:

erters (INV2, INV4, INV6)

Rating 125 volts DC/120 volts AC, 15 kVA, any pf, 2 wire, ungrounded Voltage regulation (%) +/-1 Frequency stability (%) +/-0.5 Overload capability (%) 125% of continuous rating for 5 minutes at any power factor Transfer time of static switch Zero break erters (INV1,INV3, INV5)

Rating 125 volts DC/122 volts AC 10 kVA, any pf, 2 wire, undergrounded Voltage regulation (%) +/-2 Frequency stability (%) +/-0.5 Overload capability (%) 125% of continuous rating for 5 minutes at any power factor Transfer time of static switch Zero break ommon inverter trouble alarm for each Inverter and Static Switch is provided in the Control

m. The following alarms with local alarm lights, except as noted, are tied to the common erter trouble alarm:

rms - INV2/4/6 Synchronism Fail Input CB Tripped Output Undervoltage

AC Ground Fault Over Temperature (inverters only)

Reverse Polarity Low Air Flow (static switches only/no local alarm light)

Static Switch Bypassed (no local alarm light) rms - INV1/3/5 Inverter Output Overload(1)

Out of Sync(1)

Low DC Voltage(1)

Low DC Disconnect(1)

Battery Supplying Load (Local Alarm Only)

Bypass Source Failure(1)

Low AC Output Voltage(1)

Bypass Source Supplying Load (Independent Alarm to Main Control Board)

Over Temperature(1)

L1 To Ground (Local Alarm Only)

Fan Failure(1)

Common Alarm enotes input sources to the Common Alarm at Main Control Board ive and passive components of the reactor protective system, engineered safety feature circuits the emergency power system are designed to meet the seismic design requirements. The ipment and their components are designed to function before, during, and after an operating s earthquake. In addition, they can sustain a design basis earthquake without any loss of ective function.

mic qualification of the Inverter (INV2, INV4, INV6) and Static Switches was demonstrated Wyle Laboratories in their Test Report Number 42384-1: Seismic Simulation Test Program

mic Qualification Review 92-034: DC/AC Inverter Replacement. Seismic Qualification of erters (INV1, INV3, INV5) and static switches was demonstrated by National Technical tems Laboratories and documented in their Test Report Number PR036428-TP-15, Rev. 1 d 8/14/2017.

mic qualification tests were performed for five (5) Operational Basis Earthquakes (OBEs) one (1) Safe Shutdown Earthquake (SSE). The testing was performed to industry standard E 344-75, which exceeds original qualification requirements for MP2. These were described ualification to IEEE 344-71, supplemented by the requirement that simultaneous horizontal vertical motions were required during testing. As such, the seismic qualification testing for Inverter/Static Switch assembly was successfully performed in accordance with plant design uirements.

distribution panels provide feeder protection by the use of molded case circuit breakers with mal-magnetic trips. Three panelboards were tested under simulated seismic conditions; two of well-mounted type and one floor mounted. These panelboards are representative of the eight g used. One was tested in five directions, and the other two in two biaxial positions. The mic simulation was accomplished by utilizing a pulse amplitude modulated sine wave. The specimens were subjected to five such pulses at each resonant frequency and the frequencies he building resonances. The acceleration amplitudes were as required by the criteria of this ect. All specimens were found satisfactory at even higher levels. Circuit breakers and an ervoltage relay were monitored and all performed satisfactorily.

3 SYSTEM OPERATION 3.1 Normal Operation power supplied by the above sources is used for essential control systems as illustrated in ure 8.5-2.

3.2 Emergency Operation changes are required in this system to cope with any unit emergency situation.

4 AVAILABILITY AND RELIABILITY 4.1 Special Features means of a synchronizing signal, the inverter output is always in synchronism with its ciated static switch's alternate source. Under this condition, transfer to the alternate source be made at any time with no bump due to voltage difference or phase displacement. The ic switch will transfer the AC load to the alternate source under any of the following ditions:

Inverter failure 4.2 Tests and Inspections h of the four vital inverters can be removed from service for inspection of its components, and an operational test. These tests can be done individually by manually transferring the inverter (zero break) to its associated alternate source. The static switch can be removed from service a manual bypass switch. However, during this period of time, the associated alternate source is onger available.

4.3 Additional Features backup sources for inverters 1 and 2 are inverters 5 and 6, respectively. Inverters 1 and 2 are chronized to inverters 5 and 6 via static switches VS1 and VS2, respectively.

erters 3 and 4 are backed up by and synchronized to the normal source UPS or the backup 480/

-120 regulating transformers via VR11 and VR21 and static switches VS3 and VS4, ectively.

internal frequency reference is used to keep the output of the inverter at 60 Hz +/-0.5% if the rnate source is lost or out of tolerance. It is also used to prevent an out-of-synchronization sfer.

1 DESIGN BASES 1.1 Functional Requirements ddition to transmitting electric power from the proper source to the designed load device, e facilities must be of a type and be properly installed and segregated to function during all tulated accident conditions.

1.2 Design Criteria electrical loading of conductors does not exceed, and is generally less than, the ampacities mmended by American Institute of Electrical Engineers - Insulated Power Cable Engineers ociation (AIEE-IPCEA) Power Cable Ampacities, (joint publications S-135-2 and P , 1962), and in open-top cable trays without maintained spacing in between cables the acities recommended by IPCEA-Institute of Electrical and Electronics Engineers (IEEE),

t publication, IPCEA Publication Number P-54-440, and National Electrical Manufacturers ociation (NEMA) Publication Number. WC 51-1972.

percent cross-section fill of wireways is governed by the allowable cable ampacities.

physical support of wireways meet the recommendations of Chapters 2 and 3 of the National ctrical Code, 1971.

aration of conductors and of their wireways meets the requirements of Section 4 of IEEE 279, 1, Sections 4 and 5 of IEEE Standard 308, 1971, Criteria 1, 2, 3, 4, 17 and 18 of Appendix A 0 CFR Part 50. Electrical penetration assemblies conform to IEEE 317, 1971 or 1976.

2 SYSTEM DESCRIPTION 2.1 System le types required to operate inside the containment after an accident are tested in an ironment more severe than that expected in service. All cables have a sufficient degree of e resistance to obviate the need for flame retardant coating or special fire extinguishing ems.

detection is provided by a system of fire and smoke detector heads in the areas listed below.

power supply for this detector system comes from a 125 volt DC panelboard, as described in tion 8.6.2.1. In the event of smoke or flame in these areas, an annunciator in the control room lays the alarm. Additional fire protection is provided as described in Section 9.10. The areas ered by ionization type detector heads are as follows:

Computer room

Main exhaust equipment room Fuel handling area Auxiliary building and radwaste ventilating room Cable spreading room Electrical penetration rooms Cable vault Medium-voltage switchgear rooms Low-voltage switchgear rooms Cable chases 2.2 Components raceway system is made up of cable trays, conduits and underground ducts, with the electrical les contained therein.

le trays are of galvanized steel, ladder type or solid bottom, with solid covers where required.

gers for trays carrying vital circuits are designed to withstand seismic disturbances as cribed in Sections 5.8.1 and 5.8.1.1.

duits are galvanized rigid steel where embedded in reinforced concrete in building slabs. The t banks going to the intake structure are heavily reinforced and will withstand a seismic urbance, as noted in Section 5.8.2.3.

in-line splices of conductors are made only in metal enclosures such as terminal boxes and tion boxes or in designated splicing areas of the cable raceways.

le 8.7-1 lists the physical and electrical characteristics of the cables that are used, and cates the qualification tests. The certified results of such tests are available for inspection.

le from vendors and of materials other than those listed in Table 8.7-1 are used when qualified accordance with the applicable characteristics, standards, tests and the required service ditions.

electrical penetration assemblies through the wall of the containment structure form part of containment pressure boundary, as described in Section 5.2.6.1.1. The low voltage power and trol modules are mounted in a stainless steel header plate and are designed to meet or exceed requirements of IEEE Standard 317, 1976. The medium voltage power penetrations are gned to meet or exceed all requirements of IEEE Standard 317, 1971. Replacement medium age power penetration modules are designed to meet or exceed all requirements of IEEE ndard 317, 1976. A complete prototype and production test program demonstrated the ability of the assemblies for operation under the prescribed service conditions. These tests

conductors contained therein meet all criteria applying to each class of service. The high-age conductors terminate in a stress cone and lug. Low voltage power cables larger than 4/0 G terminate in lugs rigidly fixed in a terminal box at each end of the penetration assembly. All r low-voltage power, control, and instrument cables except for Class 1E instrumentation and Q required circuits are terminated on terminal blocks enclosed in the penetration boxes at both s of the penetrations. The Class 1E instrumentation and required EEQ circuits are terminated h EEQ qualified terminations at both ends of the penetrations. Incore detection cables, coaxial le, and certain special multiconductor cables are terminated in connectors mounted in terminal es at both ends of the penetration assembly. All terminal boxes are designed for NEMA IV ice.

eak rate test is performed on each penetration assembly following its installation. This test is able of detecting a leak rate of 1 x 10-2 cc/sec of dry nitrogen at ambient temperature when imum design pressure is applied across the penetration assembly barrier. To effect this test, h assembly is fitted with a gage to monitor the pressure, and is then charged with 30 psig of ogen. The assembly is so designed that all seals, including conductor seals, are monitored by gage.

2.3 Cable Ampacities maximum ampacities for cable installations at Millstone Unit 2 are based upon the following:

Conductor temperature does not exceed 90°C.

General Plant Areas are normally considered to be 50°C for ampacity analyses except specific locations (e.g., intake structure).

Standard tray fill is 35 percent. When tray fill is above 35 percent the higher tray fill number is used.

pacities for cable installations in Free Air, Conduit, Maintained Space Cable Trays, and erground Ductbanks are based upon IEEE S-135, IPCEA P-46-426, 1962. Ampacities for le installations in Random Spaced Cable Trays are based upon ICEA P-54-440, NEMA

-51, 1972. Cables with sizes or installations not identified in the standards above, have acities based on published industry papers or published vendor data.

3 AVAILABILITY AND RELIABILITY 3.1 Separation raceway systems are so designed that any one raceway channel may be physically sacrificed er accident conditions. The layout drawings in Figure 8.7-1 show typical examples of the aration of raceways serving different channels.

inst damage from external fire, missile, or other accidents.

ere these spacings between trays of redundant systems cannot be maintained (physical tructions, points of necessary convergence, crossovers, etc.), barriers are provided to preserve physical and electrical integrity of the cables.

tical stacking of separate redundant trays is avoided where possible.

ere separate redundant trays must be stacked with less than 4 feet vertical separation and/or r horizontal separation is less than 18 inches, rated fire barriers must be used. In the cable lt, where an existing automatic detection and suppression system is located, separation iers are not required.

he case of crossover of trays carrying redundant cables, there shall be a minimum separation of

. clear space between them with a barrier (equivalent to 0.5 inch of Marinite 36).

ically, rated fire barrier material employed to enhance raceway separation is one-half inch inite 36, or equivalent. Installation will be as follows:

a. Horizontal Separation. A vertical barrier, one foot above and one foot below the trays, or to the ceiling or floor.

b. Vertical Separation. A horizontal barrier between trays extending one foot each side of the tray system.

c. Cross-overs. A horizontal barrier extending out one foot from each side of each tray, and five feet along each tray from the crossover.

ieu of the above, conduit or a totally enclosed tray may be used and the two channels do not ch each other. For certain configurations, trays with ventilated covers, or cables in Sil-temp p, are considered enclosed raceways.

erally, no more than one channel of separate redundant systems is run through a compartment taining machines with flywheels. Where this cannot be avoided, each case is evaluated for itional protection. Similarly, no more than one channel is generally routed through an area taining high pressure (275 psi and over) piping. Where necessary, the redundant raceway will un at least ten feet from such piping. Where this spacing cannot be achieved, pipe restraints provided and each case is evaluated for additional protection.

ere routing is unavoidable through an area subject to a possible open accumulation of ntities (gallons) of oil or other combustible liquids as a result of rupture or leakage of a fluid em, a single separation channel only is routed through this area. Furthermore, the cables are ected from dripping liquids by conduit or covered tray.

a. 6900 volt power

b. 4160 volt power

c. 480 volt load center subfeeders

d. *480 volt power and general control

e. *Shielded control and instrumentation

(*Shielded control and instrumentation cables may be run with unshielded control and instrumentation for short distances such as risers into equipment).

hin each of these classifications, nonvital cable may be run with vital cables. However, a vital cable is never routed in raceways of more than one separation channel.

l circuits, components, and equipment are those that are safety related. That is, the safe ration and shutdown of the nuclear system is dependent on them. Vital systems meet the single ure criterion and therefore are redundant and separate.

ere indicators and other devices are not essential for the safe functioning of a vital system, ent and potential transformer secondaries or other low-energy circuits feeding such devices considered nonvital circuits.

ipment, devices, cables and raceways have an assigned number that indicates if they are in l service or not, and also indicates the channel. These designations are shown on one-line and e-line diagrams, schematics, circuit and raceway schedules, and the instrument index.

Z prefix on a cable, conduit or tray number indicates a vital system. The absence of the Z ix indicates nonvital service. The first figure of a cable, conduit or tray number designates the nnel. Such an alpha-numeric prefix is called the Facility Code, and its use is further explained able 8.7-4.

l power and control cables fall mainly into two redundancy classifications; Channel Z1 and nnel Z2. In a few cases there is also a Channel Z5, which is a system that can be transferred m one source to another, and is run as described below. Cables such as those in reactor ection service are assigned to Channels Z1, Z2, Z3 and Z4. As shown in Table 8.7-4, nonvital nnel 1 may be routed with vital Channel Z1, and Channel 2 with Channel Z2. Low level ered signal outputs from Z3 and Z4 channels of a four-channel instrument system may be run h nonvital channels 1 and 2 respectively. Where the system lacks a current limiting feature, Z3 Z4 are run separately.

h Pressure Safety Injection (HPSI) pump P41B. The power circuits and the control circuits for equipment are all transferred simultaneously to Channel Z1 or Z2 sources. Thus, their circuits routed together as Channel Z5. The Z5 control circuit and power circuit for the spare 480 volt rging pump P18B, are transferred to Z1 or Z2 sources independent of the above circuits.

ce, the Z5 charging pump circuits are routed separately from those associated with bus A-5.

vital Channel 5 circuits are those associated with instrument loops or metering circuits.

nnels 5 and Z5 circuits are routed together only where it can be demonstrated that their sfer to Channel 1 (Z1) or 2 (Z2) sources does not impair the separation of redundant safety ted circuits.

turbine driven AFP, the steam inlet valve, and speed adjuster motor have the capability of g transferred from their normal power supply Facility Z2 125VDC (Panel DV-20) to Facility 125VDC (Panel DV-10). The transfer is accomplished by switching the position of two key-ed isolation switches on panel C-05 in the event of a loss of Facility Z2 125 or a loss of DC el DV-20. The associated wiring from panel C-05 is routed in dedicated Z5 conduit to panel 1, panel C-10 and ultimately to the steam inlet valve and the speed adjuster motor.

tdown Cooling Suction Header Containment Isolation valve 2-SI-651, auxiliary spray rging header supply valve 2-CH-517 and Loop 1A charging header supply valve 2-CH-519 e the capability of being supplied power from either Facility Z1 or Z2. However, these valves not Facility Z5 components (Sections 8.4 and 8.5). The load side of the disconnect switches 2-SI-651 are routed Z1 and the load side of the transfer switches for 2-CH-517 and 2-CH-519 routed Z2. The transfer from the normal 480 volt for 2-SI-651, is accomplished through ual operation of local Kirk-keyed transfer switches which prevent tying the two motor control ter buses together. Upon transfer to Facility Z2, the control for valve 2-SI-651 will be sferred from the control room to the local control panel. The transfer from the normal VDC for 2-CH-517 and 2-CH-519 is accomplished through manual operation of key-locked ctor switches, located on panel C02, which prevent tying the two 125 VDC power sources ther. These manual transfer schemes are consistent with the requirements of Safety Guide 6.

mputer and annunciator circuits are considered nonvital. Their inputs are from nonvital nnels 1 and 2 that may be routed with vital circuits as shown in Table 8.7-4. The Channel 1 2 segregation for the nonvital circuits is lost when they enter the final raceways at the puter or the annunciator terminal cabinets. The 480 volt power supply to the computer is uced to 120 volts by an uninterruptible power supply (preferred) or a regulating transformer ernate). The internal power supply provides 36 volts (fused one-half amp) to the digital inputs, the analog inputs are 10-50 mA. The power supply to the annunciator is from two separate undant AC to DC power supply systems which isolate the annunciator DC voltage from the power sources and isolate the two AC power sources from each other.

control element drive system (CEDS), including the CEDS logic cabinets, are also sidered nonvital. Two separate feeders, one from each of the two nonvital 120 VAC instrument es, supply control power to the logic cabinets. The feeder cables are routed in separate way from the distribution panels to the cabinets, but are ultimately bundled together within a

ribution panels provide isolation between the two buses. No redundancy is intended, or uired, for the CEDS logic cabinet power supplies.

power supply equipment is identified with respect to its source. Odd first digits are assigned to nnel 1; i.e., B1, B12, etc. Even first digits are assigned to Channel 2; i.e., B2, B21, etc.

assist in verifying proper separation, the jackets of all cables are color coded. Table 8.7-4 cates the physical separation applied to cables and raceways, and the cable jacket color for h case.

rtures for entrance of redundant vital cables into control boards, panels and relay racks are arated by at least twelve inches of air space. Where this cannot be accomplished, the entrance ade with conduit or enclosed tray.

undant vital cables terminate on terminal blocks at least six inches apart. Internal wiring of undant vital circuits, and any associated devices, is separated by a minimum of six inches.

ere the minimum spatial separation of six inches is not feasible, nonflammable heat shrinkable ng, noncombustible barriers or conduit are used to provide separation. Exceptions to these eria may be permitted on an individual basis with analysis and documentation of acceptability he Electrical Separation specification. Acceptability of lesser separation should be based on ree of hazard and mitigative measures which demonstrate that the effects of lesser separation not degrade Class 1E safe shutdown circuits and equipment below an acceptable level.

eptions cannot be taken between redundant vital wires/devices inside control panels. Nonvital nnels may be wired to the same device, but their conductors are bundled separately.

enever practicable, shipping splits and structural stiffeners are utilized as natural barriers. The iers are comprised of two sheets of steel plates with a minimum of one inch air space or lating fire-resistant material in between, if devices and/or wiring are mounted on both faces of barrier. If devices and/or wiring are mounted on the barrier on only one face, a single sheet of l plate for isolation is satisfactory provided devices and/or wiring on the other side are alled at least one inch away from the barrier. The barriers are properly supported for structural ngth, and extend from top to bottom and front to back to a depth which provides a minimum of inches separation between channels.

ical layouts illustrating the separation of redundant wireways are shown in Figure 8.7-1.

3.2 Tests and Inspections various documents indicating the separate routing of redundant cables are carefully cross-cked during the design of the system. The color coded jackets of the cables permit a visual ection to verify that the separation criteria are observed.

rioration of the insulation.

pressure gages on the electrical penetration assemblies are located in the auxiliary building etration rooms and are readily accessible. These assemblies remain charged with nitrogen ughout their life, and a pressure reading will be taken and recorded periodically.

Revision 3806/30/20 TABLE 8.7-1 CABLE CHARACTERISTICS CONDUCTORS PROTOTYPE TESTS (CERTIFIED) FACTORY TESTS (CERTIFIED)

POST-ACCI-VOLTAGE INSULA- RADIATION DENT ENVI- ELECTRI- APPLICABLE TYPE RATING SERVICE TYPE STRAND TEMP TION JACKET RESISTANCE PHYSICAL ELECTRICAL FLAME RONMENT FLAME CAL OTHER STANDARDS VENDOR COMMENTS MEDIUM 8 KV 6.9 KV CU AL Class B 90C EPR/CSPE - A.O. Aged 7 Per IPCEA Per IPCEA S Passes Horiz. N/A Passes Per IPCEA Corona IPCEA General Each VOLTAGE days 121 C 5x107 S-68-516 81 Sect 6.0 AC, & Vert. Tests IPCEA S-19-81 Level & S-68-516 Cable Conductor POWER Rad Phys. Test Sect 6.0 DC, IR, PF, SIC, per SPEC, S-19-81 Sect Corona S-19-81 Shielded Elec Test Flame Tensile, Corona, Level per Passes 6.0 Factor 5 KV 4.16 KV CU AL Class B 90C EPR/CSPE - Test Elongation, AEIC No. 5 IPCEA S N/A Passes Per IPCEA Corona IPCEA General Each Aging, 81 Sect 6.19 IPCEA S-19-81 Level & S-68-516 Cable Conductor Ozone, S-19-81 Sect Corona S-19-81 Shielded Moisture 6.0 Factor Absorption LOW 1 KV 480 VAC CU Class B 90C EPR/CSPE CSPE Preaged 7 days, Per IPCEA Per IPCEA Passes Horiz. 4.9x 108 R 52 Passes Per IPCEA - IPCEA Anaconda VOLTAGE Note (1) 125 VC 121 C S-68-516 S-19-81 Sect 6.0 & Vert. Tests psig 292°F IPCEA S-19-81 S-68-516 POWER 5x107RAD Sect 6.0 per SPEC, 100% RH 11/2 S-19-81 Sect S-19-81 passes 1/2% boric 6.0 IPCEA Sect 6 acid by wt CONTROL 1 KV Note 1 125 VDC CU Class B 70C Kerite FR Kerite FR Results Available Stated HI POT & IR Tests Passes Horiz. Results Passes HI POT & IR - - Kerite Test Results 120 VAC minimum on previous cable & Vertical available IPCEA Test on each Are tensile & Tests S-19-81 Sect Length Proprietary elongation 6.0 INSTRUMENT 600 V - CU Class B - Flame Neoprene 2x108 Rad See Note (2) Passed AC hi-pot 2/C number See Note (3) Passes HI POT, IR & - IPCEA Cerro Retardant and IR tests as 16 passed per IPCEA Cdr Res on each S-66-524 XLPE specified Spec para S-19-81 Sect reel S-19-81 MPS-2 FSAR SPECIAL 600 V - CU and Class B and - Flame Neoprene 8.4.3.2 6.0 - IPCEA Cerro INCORE TC Solid Retardant S-66-524 CABLES Type K XLPE S-19-81 COAX - - - - - XLPE CSPE Results of previous tests on similar cable; 1x108 rad Available N/A Passed Per MIL-C-17D Physicals MIL-C-17D BIW min.; physical, elect. & flame test data 9/73 IPCEA HI POT Imped, per IPCEA IPCEA S-19-81, IR Cap S-66-524, S-66-524 Sect 6.0 S-19-81 S-19-81 COMMUNC 600 - CU 16 - Flame Flame - - - - - - - - - Gai-Tronics Resistant Resistant 105C PVC 105C PVC THERMO- 300 - Type E Solid - Flame CSPE N/A N/A N/A 2/C N/A Passed Per IPCEA Conductor IPCEA BIW COUPLE Retardant number16 IPCEA S-66-524 DC S-66-524 ANSI XLPE passed per S-19-81, resistant C96.1-1964 Spec para Sect 6.0 8.3.2.2 (1) In addition to the 1 kV voltage to be used for Low Voltage Power and Control Cables, it has been justified, September/October 1981 memos GEE-81-776/GEE-81-845, that 600V Insulation can also be used for new and replacement cables.

(2) Tested for tensile, elongation, aging, heat distortion, ozone and moisture absorption.

(3) Pre-aged 7 days at 121C, 2x108 Rad, 104 psig, 340°F, 2% BA, Hipot, IR, Flame Tests, also Note 2.

8.7-9

ision 3806/30/20 Facility Code Function Channel 1 Channel 3 Channel 2 Channel 4 Channel 5 Vital Z1 Z3 Z2 Z4 Z5 Nonvital 1 -- 2 -- 5 ol Vital Z1 Z3 Z2 Z4 Z5 Nonvital 1 -- 2 -- 5 nnel Instrument Vital Z1 -- Z2 -- --

Nonvital 1 -- 2 -- --

nnel Instrument Vital Z1 Z3 Z2 Z4 --

Nonvital -- -- -- -- --

esignation Vital A C B D --

MPS-2 FSAR Nonvital X -- Y -- --

Code Vital Red Green Yellow Blue Orange Nonvital Black -- White -- Gray 8.7-12

figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

INCHES (SHEET 2) figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

INCHES (SHEET 3) figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.

INCHES (SHEETS 4) figure indicated above represents an engineering controlled drawing that is Incorporated by erence in the MPS-2 FSAR. Refer to the List of Effective Figures for the related drawing ber and the controlled plant drawing for the latest revision.