ML17226A144

River Bend Station, Unit 1, Revision 25 to the Updated Safety Analysis Report, Chapter 8, Section 8.1 Through 8.3

ML17226A144
Person / Time
Site:	River Bend
Issue date:	07/28/2017
From:	Entergy Operations
To:	Office of Nuclear Reactor Regulation, Office of Nuclear Material Safety and Safeguards
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References
RBG-47776, RBF1-17-0089
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Text

RBS USAR Revision 11 8.1-1 October 1998 CHAPTER 8 ELECTRIC POWER

8.1 INTRODUCTION

8.1.1 Utility

Grid Description The Gulf States Utilities Company (GSU) electrical system consists of interconnected fossil fuel plants and future plants

supplying electric energy over a 500/230/138-kV transmission

system (Fig. 8.1-1 through 8.1-3). 11GSU, a member of the Southeastern Electric Reliability Council, is interconnected with Arkansas Power and Light Company (AP&L),

Mississippi Power and Light Company (MP&L), Louisiana Power and Light Company (LP&L), and Central Louisiana Electric Company (CLECo). Prior to January 1, 1998, GSU was a member of the

Southwest Power Pool.

11The River Bend Station Unit 1 main generator is rated 1,151 MVA, 0.9 pf, 22-kV, 1,800 rpm, three-phase, 60 Hz.

The output of the station is delivered to Fancy Point Substation, a 230/500-kV substation (Fig. 8.1-4 and 8.1-5) via a 230-kV line.

This substation consists of 230-kV bays and 500-kV bays.

Transmission lines at 230-kV feed power to the GSU 230-kV system, the central part of Baton Rouge area by connecting to the Enjay Substation, the eastern part by connecting to the Coly Substation, and the northern part by connecting to the Port Hudson Substation. Power is also fed at 500-kV to the GSU system and to the power pool. The 500-kV, 230-kV, and 138-kV systems

are interconnected at various locations.

8.1.2 Interconnections

11The transmission system from GSU's generation facilities is closely integrated with those of other utilities in the Southwest Power Pool and the Southeastern Electric Reliability Council. As of the year 1984, GSU expects to have 11 interconnections to CLECo at 138-kV and 230-kV; 8 interconnections to Middle South System (MSS) at 115-kV, 138-kV, 230-kV, and 500-kV voltage

levels; 1 interconnection at 345-kV to the Southwestern Electric Power Company (SWEPCo); and 3 interconnections at 230-kV and 500-kV to the Cajun Electric Power Cooperative, Incorporated (CEPCo).

Table 8.1-1 is a listing of the tie lines, voltage levels of

interconnected buses, and utilities, which are projected for the year 1984. In 11 RBS USAR Revision 22 8.1-2 addition to the listed interconnections, new transmission lines are expected to be placed in service with installation of future

units.

8.1.3 Transmission

System at Site

Section 8.2.1, along with Fig. 8.1-4 through 8.1-7, and 8.2-2, describes the transmission system at the site.

8.1.4 Onsite

AC Systems 6 4 River Bend Station is provided power from the 230-kV bays of the Fancy Point Substation via two physically and electrically independent lines. Each 230-kV line is terminated at a transformer yard. The two transformer yards, designated yard 1 and yard 2A, are physically separated from each other.

Transformer yard 1 is located adjacent to the east wall of the turbine building, while transformer yard 2A is located outside the security fence, southwest of the turbine building.

Transformer yard 1 contains three normal station service transformers, 1STX-XNS1A, 1STX-XNS1B and 1STX-XNS1C, and two preferred station service transformers, 1RTX-XSR1C and 1RTX-XSR1E, in addition to the two main stepup transformers 1MTX-XM1 and 1MTX-XM2. Transformer yard 2A contains two preferred station service transformers, 1RTX-XSR1F and 1RTX-XSR1D. The transformers in both transformer yards support the normal operation and safe shutdown of River Bend Station. See Fig. 8.2-

2 for the configuration of the two transformer yards.

4 6 The main generator leads of River Bend Station are connected by means of isolated phase bus duct to two 518.6/788.5 MVA, 65°C, FOA, 21.45-kV delta 150-kV BIL to 230-kV grounded wye 750-kV BIL, three-phase, 60 Hz main stepup transformers, 1MTX-XM1 and 1MTX-XM2. These two half-size transformers are paralleled on both the low (input) and high (output) sides. Disconnecting means are provided to allow the removal of one transformer from service, thus permitting the unit to continue generating power. The single 230-kV output circuit has bundled conductors, and is routed on a double circuit steel tower line to the 230-kV bays of the Fancy Point Substation approximately 4,000 ft southwest of

the plant.

The main generator leads of River Bend Station are also connected

by means of isolated phase bus duct to three normal station

service transformers with the following ratings:

RBS USAR Revision 22 8.1-3 1. Normal station service transformer s 1STX-XNS1A and 1STX-XNS1B are rated 47.5 MVA, 65°C, FOA, 22-kV delta 150-kV BIL to 13.8-kV delta 110-kV BIL, three-phase, 60 Hz.

2. Normal station service transformer 1STX-XNS1C is rated 16 MVA, 65°C, FOA, 22-kV delta, 150-kV BIL primary with two secondary windings each rated 8 MVA with 4.16-kV

resistance grounded wye 75-kV BIL, three-phase, 60 Hz.

All three normal station service transformers are paralleled on their high (input) sides while their low (output) sides are routed to their separate 13.8-kV and 4.16-kV buses.

Preferred plant ac station service power is provided by two physically and electrically independent 230-kV lines originating

in the 230-kV bays of the Fancy Point Substation and terminating at transformer yards 1 and 2A. These 230-kV lines are installed on double circuit transmission towers, as shown in Fig. 8.2-1, with the station service power circuits located adjacent to the generator output circuits. Their function is to provide all power requirements when normal power is unavailable. Preferred

station service transformers are rated as follows: 13 6 4 1. Preferred station service transformer 1RTX-XSR1E is rated 51/68/85 MVA, 55°C OA/FOA/FOA 230-kV Delta 750-kV BIL to 13.8-kV ground wye 110-kV BIL, three-phase, 60 Hz and

1RTX-XSR1F is rated 51/68/85 MVA, 55°C OA/FOA/FOA 230-kV delta 750-kV BIL to 13.8 kV grounded wye 110-kV BIL, three-phase, 60Hz.

4 6 13 2. Preferred station service transformers 1RTX-XSR1C and 1RTX-XSR1D are rated 10/12.5 MVA, 65° C OA/FA, 230-kV grounded wye 750-kV BIL to 4.16-kV resistance grounded

wye 75-kV BIL, three-phase, 60 Hz.

The arrangement of the preferred and normal station service transformers is shown on Fig. 8.1-8 and 8.1-9. Each transformer is provided with its own fire barrier and a separate deluge valve and water spray fire protection line. Separate oil pits and

retaining curbs are provided for the groups of transformers.

Oil pits and associated retention curbs have been sized to hold

the oil from the largest transformer draining into the pit plus

the water from the operation of fire protection systems of two

transformers for 10 minutes.

RBS USAR Revision 22 8.1-4 This design prevents a fire or oil spill associated with one transformer from affecting the operability of other transformers.

Fire barriers are designed utilizing guidance from applicable

NFPA requirements.

The secondaries of transformers located in both transformer yards

are connected to 13.8-kV and 4.16-kV buses via cables installed

in concrete-encased ductlines in the yard and cable tray inside the power plant. Fig. 8.1-4 and 8.1-6 illustrate the station

service electrical system.

The two double-circuit tower lines from the Fancy Point

Substation to the power plant are of the steel pole, H-frame structure design on the same right-of-way. These 230-kV tower structures are so designed and physically spaced that failure of

one does not jeopardize the operation of the other (Fig. 8.2-1). 7 6 Each section of the 13.8-KV and 4.16-KV buses has access to the assigned normal and assigned preferred station transformers which are connected to the buses by circuit breakers controlled from the main control room. In addition, if the unit auxiliary loads

are being supplied through the normal transformers, automated throw-over from normal to preferred source occurs (as described in Section 8.3.1.1.3) after unit trip or upon loss of normal power. Each of the two 13.8-kV buses, 1NPS-SWG1A and 1NPS-SWG1B, and each of the 4.16-kV buses, 1NNS-SWG1A and 1NNS-SWG1B, support redundant equipment. 13.8-kV buses 1NPS-SWG1C and 1NPS-SWG1D have access to the assigned preferred station service transformers 1RTX-XSR1E and 1RTX-XSR1F respectively, which are connected to the buses by circuit breakers controlled from the

main control room.

6 Each of the two primary 4.16-kV in-station normal buses, 1NNS-SWG1A and 1NNS-SWG1B, can be energized via the dual secondaries of normal station service transformer 1STX-XNS1C. NNS-SWG1A can also be energized from preferred station transformer 1RTX-XSR1C and NNS-SWG1B can also be energized from preferred station transformer 1RTX-XSR1D. A third 4.16-kV in-station normal swing bus, 1NNS-SWG1C, is subordinate to one or the other of the above

4.16-kV normal buses.

7 Two of the standby 4.16-kV buses, 1ENS*SWG1A and 1ENS*SWG1B, are connected to preferred station service transformers, 1RTX-XSR1C and 1RTX-XSR1D, respectively. The standby 4.16-kV bus, 1E22*S004, is normally connected to the 4.16-kV in-station normal swing bus 1NNS-SWG1C. Each of these standby buses has a standby

diesel generator capable of supporting it upon loss of normal and preferred power. Switching allows each of the 4.16-kV standby buses to have access to one of the two 4.16-kV in-station normal

buses while the 4.16-kV standby bus 1E22*S004 is subordinate to the 4.16-kV in-station swing bus 1NNS-SWG1C. The 4.16-kV standby buses serve redundant loads and are electrically isolated from

each other.

RBS USAR Revision 20 8.1-5 8.1.5 Onsite DC Systems 6The onsite dc power systems provide power for control, instrumentation, indication, valve operators, solenoid valves, uninterruptible power supplies, and essential dc motors. There are three physically and electrically independent standby 125-V

dc systems (including buses 1ENB*SWG01A, 1ENB*SWG01B, and 1E22*S001, which supply power to the standby diesel auxiliary

loads) and seven normal 125-V dc systems, including buses 1BYS-SWG01A, 1BYS-SWG01B, and 1IHS-SWG01D, and 125 VDC panels 1BYS-PNL01, 1BYS-PNL04, 1BYS-PNL06, and 1BXY-PNL01 which supply power

to nonsafety-related loads as shown on Fig. 8.3-6.

68.1.6 Identification of Safety-Related Systems 8.1.6.1 System Functions Sections 8.3.1.1.2.1 and 8.3.1.3, and Table 8.3-1 identify safety-related systems and their functions. 8.1.6.2 Power Supply Sources Power supply sources to safety-related systems, as shown in Fig. 8.1-4, consist of the main generator through one three-

winding normal station service transformer, the two redundant offsite 230-kV transmission lines through two preferred station service transformers, two standby ac diesel generators, and a high pressure core spray (HPCS) ac diesel generator. Standby

power is not connected to or influenced by the 13.8-kV system. 13Each of the three diesel generators 1EGS*EG1A, 1EGS*EG1B, and 1E22*S001G1C is connected to 4.16-kV standby buses 1ENS*SWG1A, 1ENS*SWG1B, and 1E22*S004, respectively. Electric power to the safety-related systems from the normal and preferred station service transformers is supplied as follows. The dual secondaries of normal station service transformer 1STX-XNS1C can be connected to two normal 4.16-kV buses 1NNS-SWG1A and 1NNS-SWG1B through normally open breakers. The two normal 4.16-kV buses are connected to the preferred station service transformers through normally closed breakers. The normal 4.16-kV swing bus 1NNS-SWG1C is subordinate to one or the other of the above normal 4.16-kV buses. The normal 4.16-kV bus 1NNS-SWG1A has a normally

open tie to standby 4.16-kV bus 1ENS*SWG1B at the standby bus

.Normal 4.16-kV bus 1NNS-SWG1B has a normally open tie to standby 4.16-kV bus 1ENS*SWG1A at the standby bus. Normal 4.16-kV swing bus 1NNS-SWG1C has two 4.16-kV sources of power from either normal 4.16-kV bus 1NNS-SWG1Bor normal 4.16-kV bus 1NNS-SWG1A which is controlled by station operating procedure. Normal 4.16-kV 13 RBS USAR 8.1-6 August 1987 swing bus 1NNS-SWG1C has a 4.16-kV tie to standby bus 1E22*S004.

Standby 4.16-kV buses 1ENS*SWG1A and 1ENS*SWG1B are energized from the preferred station service transformers at all times via normally closed switchgear circuit breakers connected to the

secondaries of the preferred station service transformers. 8.1.7 Identification of Safety Criteria 8.1.7.1 General Functional Design Basis Chapter 3 outlines the general engineering criteria for nuclear plant design and delineates several areas of general

classification and/or conformance which are applicable to the electrical power systems and equipment. Further clarification of some specific standards and criteria related to electrical systems is given in Chapter 7. Section 7.1.2 outlines various standards and criteria for systems which may include electrical

functions similar to electrical power systems. Specific requirements for electrical power systems and equipment are given in the following paragraphs. 8.1.7.2 Design Basis

General Design CriteriaThe conformance discussion provided in Section 3.1 for the General Design Criteria (GDC) applies to the electrical systems

in Chapter 8, as identified in Table 8.1-2.

Branch Technical Positions The conformance discussion for the Branch Technical Positions (BTPs) is referenced in Table 8.1-3.

USNRC Regulatory GuidesThe following Regulatory Guides are specifically cited as applying to the safety-related electrical power systems and equipment. Safety-related systems and equipment are designed in

accordance with the referenced Regulatory Guides as described in

Section 1.8.

RBS USAR 8.1-7 August 1987 Regulatory Guide Title 1.6 Independence Between Redundant Standby (Onsite)

Power Sources and Between their Distribution

Systems 1.9 Selection, Design and Qualification of Diesel-Generator Units Used as Standby (Onsite) Electric

Power Systems at Nuclear Power Plants 1.22 Periodic Testing of Protection System Actuation Functions 1.29 Seismic Design Classification 1.30 Quality Assurance Requirements for the Installation, Inspection, and Testing of

Instrumentation and Electric Equipment 1.32 Criteria for Electric Power Systems for Nuclear Safety-Related Power Plants 1.40 Qualification Tests of Continuous-Duty Motors Installed Inside the Containment of Water-Cooled

Nuclear Power Plant 1.41 Preoperational Testing of Redundant Onsite Electric Power Systems to Verify Proper Load Group

Assignments 1.47 Bypassed and Inoperable Status Indication for Nuclear Power Plant Safety Systems 1.53 Application of Single Failure Criterion to Nuclear Power Plant Protection Systems 1.62 Manual Initiation of Protective Action 1.63 Electric Penetration Assemblies in Containment Structures for Light-Water-Cooled Nuclear Power

Plants 1.68 Initial Test Programs for Water-Cooled Nuclear Power Plants RBS USAR 8.1-8 August 1987 Regulatory Guide Title 1.70 Standard Format and Content of Safety Analysis Reports for Nuclear Power Plants 1.73 Qualification Tests of Electric Valve Operators Installed Inside the Containment of Nuclear Power

Plants 1.75 Physical Independence of Electric Systems 1.81 Shared Emergency and Shutdown Electric Systems for Multi-Unit Nuclear Power Plants 1.89 Qualification of Class 1E Equipment for Nuclear Power Plants 1.93 Availability of Electric Power Sources 1.100 Seismic Qualification of Electric Equipment for Nuclear Power Plants 1.106 Thermal Overload Protection for Electric Motors on Motor-Operated Valves 1.108 Periodic Testing of Diesel Generator Units Used as Onsite Electric Power Systems at Nuclear Power

Plants 1.118 Periodic Testing of Electric Power and Protection Systems 1.120 Fire Protection Guidelines for Nuclear Power Plants 1.128 Installation Design and Installation of Large Lead Storage Batteries for Nuclear Power Plants 1.129 Maintenance, Testing, and Replacement of Large Lead Storage Batteries for Nuclear Power Plants RBS USAR

• Applies to Division III HPCS diesel generator only.

• • Conformance with IEEE 323-1974 is described in Section 3.11. 8.1-9 August 1987 Regulatory Guide Title 1.131 Qualification Test of Electric Cables, Field Splices, and Connections for Light-Water-Cooled

Nuclear Power Plants IEEE Standards Electrical power systems and equipment comply with the following standards of the Institute of Electrical and Electronics

Engineers (IEEE):

IEEE Standard Title279-1971 Criterion for Protection Systems for Nuclear Power Generating Stations 308-1974 Criteria for Class 1E Electric Systems Nuclear 1971* Power Generating Stations 317-1976 Electrical Penetration Assemblies in Containment Structures for Nuclear Fueled Power Generating

Stations323-1974** General Guide for Qualifying Class I Electrical Equipment for Nuclear Powered Generating Stations 334-1974 Type Test of Continuous Duty Class 1E Motors for Nuclear-Power Generating Stations 336-1971 Installation, Inspection, and Testing Requirements for Instrumentation and Requirements

for Instrumentation and Electric Equipment During

the Construction of Nuclear Power Generating

Stations338-1977 Criteria for the Periodic Testing of Nuclear 1971* Power Generating Station Protection Systems RBS USAR

• Applies to Division III HPCS diesel generator only.

• • Conformance with IEEE 323-1975 is described in Section 3.10. 8.1-10 August 1987 IEEE Standard Title344-1975** Seismic Qualification of Class I Electric Equipment for Nuclear Power Generating Stations 379-1977 Trial Use Guide for the Application of the Single 1972* Failure Criterion to Nuclear Power Generating Station Protection Systems 382-1972 Trial-Use Guide for the Type Test of Class I Electric Valve Operators for Nuclear Power

Generating Stations 383-1974 Type Test of Class 1E Electric Cable Field Splices, and Connections for Nuclear Power

Generating Station384-1974 Criteria for Separation of Class 1E Equipment and Circuits387-1977 Criteria for Diesel-Generator Units Applied as 1972* Standby Power Supplies for Nuclear Power Generating Stations 415-1976 Planning of Preoperational Testing Programs for Class 1E Power Systems for Nuclear Power

Generating Stations 420-1973 Trial Use Guide for Class 1E Control Switchboards for Nuclear Power Generating Stations 450-1975 Recommended Practice for Maintenance, Testing, and Replacement of Large Stationary Type Power

Plant and Substation Lead Storage Batteries 484-1975 Installation Design and Installation of Large Lead Storage Batteries for Generating Stations

and Substations RBS USAR 8.1-11 August 1987 Additional StandardsRelevant standards, codes, etc, are referenced in text whenever special considerations warrant. These are not generally

applicable to electrical power systems and are not listed here.

RBS USAR Revision 22 8.2-1 8.2 OFFSITE POWER SYSTEM

8.2.1 Description

8.2.1.1 Transmission System and Switchyard 16 7 The offsite power system is designed to provide reliable and redundant sources of power for starting, operation, and safe shutdown of Unit 1 in accordance with General Design Criterion (GDC) No. 17, Electric Power Systems (Table 8.1-2 and Section 3.1.2.17) and GDC No. 18, Inspection and Testing of Electric Power Systems. The offsite power system is shown in the

following figures:

7 16 1. Fig. 8.1-1 December 31, 1985, Utility Grid 2. Fig. 8.1-3 January 1, 1987, Power Pool Map

3. Fig. 8.1-4 Fancy Point Substation - 230-kV Bays and Peripheral Loads 4. Fig. 8.1-5 Fancy Point Substation - 230-kV Bays

5. Fig. 8.1-6 Station Service - One Line Diagram

6. Fig. 8.1-7 Fancy Point Substation - 500-kV Bays

7. Fig. 8.2-1 Transmission Towers to 230-kV Switchyard from the Station 8. Fig. 8.2-2 Connection of Onsite 13.8-kV and 4.16-kV Distribution System to the Preferred

Power Supply 9. Fig. 8.2-3 Transmission System

10. Figs. 8.2-4 Transmission Route Segments through 8.2-35

11. Fig. 8.2-36 Fancy Point 500-kV and 230-kV Switchyard One-Line Diagram

8.2.1.1.1 230/500-kV Switchyard

The 230-kV bays of the substation, Fig. 8.1-4 and 8.1-5, consist of two buses and positions for thirty 230-kV circuit breakers (OCB) in a breaker-and-a-half scheme, with each of the two buses being capable of carrying the total connected load. Voltage on the bus is a nominal 230 kV, with a maximum rating of 242 kV and

a minimum rating of 224.25 kV. There are three 230-kV lines serving Unit 1 along the right-of-way shown in Fig. 8.2-1, and one line connecting the 230-kV bays to the 500-kV bays via

transformers.

The 230-kV tie to the 500-kV switchyard consists of one 230-kV

line of one span, strung between the transformer bay steel and the associated A-frame structure in the 230-kV switchyard. These

230-kV leads connect the 230-kV bays to a

RBS USAR Revision 19 8.2-2 15bank of three single phase stepup transformers at the 500-kV bays. The 500-kV bays of the substation, Fig. 8.1-7, consists of

two buses and positions for six 500-kV gas circuit breakers (GCB) in a folded breaker-and-a-half configuration. The two-bus 500-kV bays located on the northwest side of and adjacent to the 230-kV bays are initially constructed as a three-breaker ring bus and are to be developed into a breaker-and-a-half scheme with the installation of future power plant units. Each bus is capable of

carrying the total connected load.

1516The two 230-kV lines previously described in Section 8.1 provide two physically and electrically independent sources of offsite power to the preferred station service transformers at the

station from the 230-kV bay of the Fancy Point Substation. The 230-kV bays are constructed with rigid aluminum tubing supported on insulators and galvanized steel towers and pedestals. The breakers are 230-kV dead tank,circuit breakers, using the breaker-and-a-half scheme. The layout of the 230-kV bays of the substation is shown in Fig. 8.1-5. The buses are constructed at 17-ft and 29-ft heights above ground. The buses

are designed to withstand a maximum fault on any section with Unit 1 operating. This is the maximum force-loading to which the buses are expected to be subjected. Similar designs have been used in the past and have proven to be adequate under all electrical fault and environmental conditions. The breaker-and-a-half design provides for the isolation of any faulted line without affecting the operation of any other line. This scheme also provides for the isolation of any one breaker in the 230-kV bus for inspection or maintenance without affecting the operation of any of the connecting lines or any other connection to the buses. The buses have adequate capacity to carry their loads under any postulated switching sequences. The design provides for the isolation of any breaker connecting Unit 1 to the

switchyard buses without limiting the operation of any line connecting to the 230-kV power grid. Either 230-kV offsite source circuit breaker can be isolated, inspected, and maintained as needed without affecting any line or unit input. Either of the 230-kV offsite source lines can be taken out of service for inspection or maintenance without jeopardizing the operation of

the other 230-kV source of offsite power.

16 RBS USAR Revision 25 8.2-3 A fault of any section of the 230-kV bus is cleared by the adjacent breakers and does not interrupt operation of any of the

remaining parts of the 230-kV switchyard bus. Only that element

connected to the faulted section is interrupted.

The 500-kV bays of the substation are located northwest of and adjacent to the 230-kV bays and are constructed of SF 6 components. The 500-kV bays are arranged in a folded breaker-and-a-half scheme, consisting of six 500-kV GCB positions. The initial installation for Unit 1 consists of three circuit breakers and three 500-kV lines in a ring bus configuration.

Fig. 8.1-7 illustrates the initial and final 500-kV configurations. There are two separate SF 6 charging systems for the 500-kV bays: one to serve the 500-kV SF 6 circuit breakers, and one to serve the 500-kV SF 6 buses, disconnecting switches, and air bushings. The initial ring bus configuration provides for the isolation of any faulted line without affecting the operation of any other line. It also provides for the isolation of any one breaker in the 500-kV SF 6 bus for inspection or maintenance without affecting the operation of any of the connecting lines or any other connections to the buses. The 500-kv buses terminate at the 500-kv SF 6 air bushings. Connections are made to the 500-kV grid and to the 230-500-kV transformers

via air-insulated, outdoor-constructed bus work and overhead

lines from these air bushings. 7 The ac auxiliary power requirements of the 230-kV and 500-kV bays are provided by two 750-kVA, 13.8-kV to 480-V oil-filled

transformers supplied from onsite 13.8-kV buses 1NPS-SWG1A and

1NPS-SWG1B.

7 The dc requirements for the Fancy Point Substation relay and control systems are provided by two 125-V batteries. Each battery system is supported by its own charger which is provided

power from the auxiliary ac power system and by an existing

source external to River Bend Station.

RBS USAR Revision 25 8.2-4 16 Control functions between the plant and the substation are provided by two diverse methods. Control cables are routed in a concrete-

encased duct bank to the substation control house. Routing within the substation between the various relay panels and control equipment is accomplished via a protected cable trench. An optic

cable underbuilt on the reserve station service steel pole lines provides another diverse method of transmitting control functions and information between the plant and substation. The optical

information is decoded at the substation and forwarded to the appropriate piece of equipment via control cables routed in a cable trench or raceway that is physically separated by 5 ft or more from

the other trench or raceway described herein. The routing separation is maintained over the route length except at termination

points where the cables route to the same piece of equipment.

16 The 125-V battery system furnishes the control power for circuit breakers in both the 500-kV and 230-kV switchyard bays. A complete loss of both 125-V battery systems, including the battery charger, prevents the operation of all circuit breakers in the switchyard.

The loss of the battery system in conjunction with a fault in the switchyard or any incoming line would require the operation of backup relaying elsewhere within the grid to clear the fault.

Offsite power will be manually restored by isolating one of the reserve station service lines to an unfaulted line in the event of severe battery damage. The estimated time to perform the subject

operation is 15 min after personnel arrive at the switchyard.

16 The battery systems are monitored remotely using a SCADA (Supervisory Control and Data Acquisition) system which provides a

low-voltage alarm to the Southwest-Transmission Operation Center (SWTOC) dispatcher in the event of malfunction. Additionally, the batteries receive a visual inspection weekly and a complete

inspection for operability to manufacturer's specifications each 6 months. The weekly inspection consists of checking the

electrolyte levels, the battery voltage, and the charge rate. The 6-month inspection includes checking the voltage and specific gravity of each cell, cleaning and retorquing the battery

connectors, and if needed, the application of an equalize charge for about 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. A form containing each of the above-mentioned items

is filled out for each inspection. Completed inspection forms are

kept on file at the Baton Rouge Substation Department.

16 All 230-kV circuit breakers are equipped with two independent trip coils and breaker failure protection for redundant power circuit protection. All of the protective relay systems for the 230-kV bays

are redundant. These systems are overlapping so that each high-voltage component is covered by at least two sets of protective relays. The primary and the backup relay systems are supplied from separate current inputs, separate dc circuits from each 125-V

battery, and are connected to separate trip coils of

RBS USAR Revision 18 8.2-5 the power circuit breakers. Cross tripping between the trip coils is used. The potentials for the primary and backup relay systems associated with the three 230-kV lines serving Unit 1 are

provided from one set of potential transformers on the north 230-

kV bus (primary) or one set of potential transformers on the south 230-kV bus (alternate). A potential transfer scheme is provided between the primary potentials and the alternate potentials. The potentials for the primary and backup relay systems associated with the other 230-kV lines are provided from one set of coupling capacitor voltage transformers on each line terminal. The potentials for the 500 to 230-kV transformer backup relaying (230 kV) are provided from one set of coupling

capacitors on the 230-kV side of the transformer.

The primary relay system for each of the three 230-kV lines serving Unit 1 is apilot wire system over a primary pilot wire circuit. The backup relay system for each of the three 230-kV

lines is a multiple-zone distance phase with directional overcurrent ground relay system over a backup pilot wire circuit. Transfer tripping of switchyard breakers for in-plant relay operations useseither the primary or backup pilot wire circuits.

The redundant pilot wire circuits are monitored

.The primary relay system for each of the other 230-kV lines is a permissive, overreaching transfer trip system

. The backup system for each of the other 230-kV lines is a three-zone distance phase and ground relay system that initiates local tripping. 16 The north and south 230-kV buses are protected with a primary restraint bus differential system and a backup restraint bus

differential system.

16The 500 to 230-kV transformer is protected on the 230-kV side by single-zone distance phase with directional overcurrent ground

relaying that initiates local tripping. All 500-kV circuit breakers are equipped with two independent trip coils and breaker-failure protection for redundant power circuit protection. All of the protective relay systems for the 500-kV bays are redundant. These systems are overlapping so that each switchyard high-voltage component is covered by at least two

sets of protective RBS USAR Revision 25 8.2-6 relays. The electromechanical backup relay system has separate current inputs and receives its power from one of the redundant 125-V battery systems. Cross tripping between the trip coils is

used. The potentials for the primary and backup relay systems

associated with the 500-kV lines are provided from one set of coupling capacitor voltage transformers on each line terminal.

The secondary potentials are separated into two systems of junction boxes in the switchyard and are treated as redundant systems from this point. The potentials for the 500 to 230-kV transformer backup relaying (500 kV) are provided from one set of

bushing potential devices on the 500-kV side of the transformer.

The primary relay systems for the two 500-kV lines are: 1) phase comparison relaying over a CS26 power line carrier channel; and

2) directional comparison tripping with phase and ground distance

relays using a frequency shift audio tone, modulated on a

microwave channel. The backup relay system for the two 500-kV

lines is a three-zone distance phase and ground relay system that

initiates local tripping. 16 16 The primary relay system for the 500-kV line to the 500 to 230-kV transformer is a separate restraint bus differential system. The

primary relay system for the 500 to 230-kV transformer is a separate restraint transformer differential system. The backup relay system (500 kV) for the 500 to 230-kV transformer is a

single zone distance phase with directional overcurrent ground

relaying that initiates local tripping.

RBS USAR Revision 198.2-716 The 230-kV and 500-kV circuit breakers can be operated either manually from the switchyard control house or remotely by either

the Southwest-Transmission Operation Center dispatcher or the River Bend Station operator. Those remotely operable by the Southwest-Transmission Operation Center dispatcher areCBs 20650, 20660, 20735, 20740, 20745

, 20765, 20770, and 20775. Those remotely operable by the River Bend Station operator areCBs 20610, 20620, 20635, 20640, 20670, and 20665.

The 500-kV circuit breakers have compressed air actuated mechanisms with stored capacity for three open and three close operations. The operations are contingent upon normal auxiliary power to the breaker during the 30 min preceding the initial operation. Switching operations from local stations upon loss of

control or motive power require that the trip or close lever

located directly on the GCB control cabinet be manually operated.

16A mimic board of the Fancy Point Substation is located in the main control room to provide remote breaker status indication.

Physical separation of the offsite power sources to include the 230-kV bays through the preferred station transformers of the onsite Class 1E power system is maintained for all credible

events.The offsite power sources are non-Class 1E with all equipment manufactured to the accepted industrial standards. This design is considered to meet the requirements of GDC 1 as evoked for the

offsite (preferred) power system. In satisfaction of GDC 3, the two offsite power systems have either spatial separation or totally enclosed raceways over their

entire length. In satisfaction of GDC 4, the two offsite power sources are routed in such a manner as to permit continuous operation of one

230-kV offsite power line during a malfunction of the second 230-

kV line. 8.2.1.1.2 Transmission System River Bend Station is connected to GSU's load demand area by a system of 230-kV and 500-kV overhead transmission lines. These lines were installed and erected from the River Bend Station's

Fancy Point Substation to the Webre Substation, RBS USAR 8.2-8 August 1987 Jaguar Bulk Substation, and McKnight Switching Station via three physically separate rights-of-way. These three rights-of-way, designated Routes I, II, and III, provide the means to integrate River Bend Station into the existing GSU electrical system. Electric output from the station is transmitted to the electrical system via these three routes

during normal plant operation. Route I runs west from the Fancy Point Substation to the Big Cajun No. 2 Power Station switchyard and continues south to Webre

Substation near Rosedale, Louisiana. Route I is 29.20 mi long. Route II, 23.75 mi long, runs southeast and south from the Fancy Point Substation to the Jaguar Bulk Substation in Scotlandville, Louisiana.Route III runs 27.20 mi east from the Fancy Point Substation to Point U, the McKnight Switching Station in McKnight, Louisiana.

The three transmission line routes are scheduled for completion

as follows:

Route I - November 1980 (completed)

Route II - May 1981 (completed)

Route III - July 1983 (completed) These transmission line routes are illustrated in Fig. 8.2-3. There are no crossovers of the 230-kV or 500-kV transmission

lines at any point along the three rights-of-way. The 230-kV transmission lines run from the 230-kV bays along Routes I and II, as follows: 1. 230-kV; Fancy Point Substation to Port Hudson, 2 lines (Route II) 2. 230-kV; Fancy Point Substation to Enjay, 1 line (Route II) 3. 230-kV; Fancy Point Substation to Cajun Electric Power Cooperative, 1 line (Route II)4. Future line, 7 lines (Routes I and II)

RBS USAR 8.2-9 August 1987 As shown on Fig. 8.1-5, there are additional 230-kV transmission lines associated with future units. All the new 230-kV lines are of the steel pole, H-frame structure design except that portion of Route II along Highway 19 which is a single-pole, steel, double-circuit structure. The 230-kV power conductors primarily consist of two conductor bundles of 649.5 kCMIL aluminum conductor, alloy reinforced (ACAR), cable spaced 45.7 cm (18 in) on center, with a nominal power capacity of 750 MVA. The 230-kV lines 351 and 352, from the Fancy Point Substation to the Jaguar Bulk Substation, utilize two 1,650 kCMIL ACAR cables per phase with a nominal power capacity of 1,200 MVA.

The minimum design phase-to-phase spacing on the 230-kV transmission line system is 4.9 m (16 ft). Two static lines are provided on each 230-kV transmission tower and consist of 5/16-in

extra high strength (EHS) steel cable. The 500-kV transmission lines run from the 500-kV bays along Routes I and III as follows:1. 500-kV; Fancy Point Substation to McKnight Substation, 1 line (Route III)2. 500-kV; Fancy Point Substation to Big Cajun No. 2, 1 line (Route I)3. 500-kV; Fancy Point Substation to 500-kV/230-kV transformers, 2 lines4. Future lines, 4 lines All 500-kV transmission lines are of the steel, lattice-type design.Two configurations of power conductors are used at the 500-kV level. Three conductor bundles of 1,024.5 kCMIL ACAR per phase spaced 45.7 cm (18 in) on center are used along Routes I and III with a nominal power capacity of 2,500 MVA. The Route I Mississippi River crossing utilizes one 3,075 kCMIL aluminum conductor steel reinforced (ACSR) cable per phase with a nominal power capacity of 2,500 MVA. The minimum phase-to-phase spacing on the 500-kV transmission line system is 11.0 m (30 ft). Two

7/16-in EHS steel cable static lines are used on each 500-kV transmission tower, with the exception of the 19 static lines used on the Mississippi River crossing which are No. 9 alumoweld

cables.

RBS USAR Revision 16 8.2-10 March 2003 All transmission lines of 230-kV and 500-kV associated with the Fancy Point Substation and River Bend Station are designed for medium loading conditions and high thunderstorm occurrence rate.

There are no unusual features of these lines. The terrain in the

Gulf States system area is flat to gently sloping. 8.2.1.1.2.1 Route Descriptions Fig. 8.2-3 illustrates the three transmission line routes and identifies the route segments referenced below.

Route IRoute I extends 29.2 mi from the Fancy Point Substation to the Webre Substation, and consists of lattice steel towers for 500-kV service with provisions for 230-kV underbuild lines, and steel

pole H-frame 230-kV towers. The 500-kV line 746 runs west from the switchyard to the Big Cajun No. 2 Power Station switchyard on twelve 500-kV lattice towers. From there, 500-kV line 745 proceeds south to the Webre Substation on 131 500-kV lattice towers with provisions for

either one or two 230-kV underbuild circuits. 16 An existing 230-kV line 715 runs southwest to the Cajun Electric Power Company Substation near the False River cutoff, and from

there to the Addis Substation with existing 230-kV line 731.

16Segment A to B originates at the substation and continues south-southwest 1.07 mi. The segment shares the same right-of-way with the first part of Route II, and provides for seven

230-kV lines on four H-frame structures and one 500-kV line 746 on lattice steel towers with provisions for two 230-kV underbuild lines. The 500-kV line and four 230-kV lines on three H-frame structures are shown on Fig. 8.2-4. Facilities for the seven 230-kV lines and one 500-kV line were constructed in 1980.

Additional 230-kV lines will be installed at a later date when

they are needed for additional capacity to support load growth in

the Gulf States service area. Segment B to C is 1.80 mi long and runs west to Point C, the Big Cajun No. 2 Power Plant switchyard. Since this segment crosses

pasture land and water, different types of towers for 500-kV line 746 have been constructed. A typical tower is shown on Fig. 8.2-

5.

RBS USAR 8.2-11 August 1987 From the switchyard at Big Cajun No. 2 (Point C) segment C to D of Route I extends 1.83 mi west and south to Point D carrying

single circuit 500-kV line 745 (Fig. 8.2-6). Segment D to E runs from Point D south and southeast to Point E. The corridor is 7.22 mi long and runs parallel to an existing right-of-way. The right-of-way on this segment carries the one existing 230-kV line 731 constructed on 230-kV single circuit wood H-frame towers and the 500-kV line 745 with provisions for a

future 230-kV underbuild line as shown on Fig. 8.2-7. Segment E to F is 9.65 mi long and extends southwest and south parallel to existing rights-of-way. This right-of-way carries 500-kV line 745 with provisions for a future 230-kV underbuild

line as shown on Fig. 8.2-8. Segment F to G is 7.22 mi long and also runs parallel to an existing right-of-way. The 500-kV line 745 tower has provisions

for two future 230-kV underbuild lines (Fig. 8.2-9 and 8.2-10). Segment G to H of Route I is 0.41 mi long and extends south parallel to the Texas and Pacific Railroad terminating at Webre Substation, Point H. This segment carries the new 500-kV line 745 with provisions for two future 230-kV underbuild lines (Fig. 8.2-11).

Route IIRoute II extends 23.75 mi from the Fancy Point Substation to the Jaguar Bulk Substation and consists of 129 230-kV steel pole H-frame towers and 47 230-kV single steel pole towers for 230-kV lines 351, 352, and 354. Each tower has provisions for carrying

two 230-kV circuits.Line Route II begins at the substation, Point A, and runs southeast to Point Q, Jaguar Bulk Substation in Scotlandville, Louisiana. The total route length is 23.75 mi and is divided

into 10 segments.Segment A to B of Route II is shared with Segment A to B of Route I and has been previously discussed in this section.Segment B to I is adjacent to an existing transmission corridor running south-southeast. The 0.71 mi segment has provisions for seven 230-kV lines on four H-frame structures, an existing 69-kV and future 230-kV lines on a fifth H-frame structure (Fig. 8.2-

12).

RBS USAR 8.2-12 August 1987 Segment I to J is 1.0 mi long. It runs northeast adjacent to an existing pipeline right-of-way and consists of five 230-kV lines and existing 69-kV line 723 on four H-frame structures (Fig. 8.2-

13).Segment J to K is 1.76 mi long. It begins at Point J and runs southeast to a point 0.19 mi south of Thompson Creek. This segment is divided into three sections (0.86 mi, 0.68 mi, and 0.19 mi) with tower configurations shown on Fig. 8.2-14 through 8.2-16. This segment accommodates four H-frame structures which carry existing 230-, 138-, 69-kV lines, and three future 230-kV

lines.Segment K to L of Route II is 2.75 mi long and is divided in two sections (Fig. 8.2-17 and 8.2-18). Segment L to M runs for 4.2 mi south and west from Point L to Port Hudson Bulk Substation, Point M. This segment consists of two double circuit and one single circuit H-frame structures

accommodating five 230-kV circuits (Fig. 8.2-19 through 8.2-24). Segment M to N (Fig. 8.2-25) is 4.83 mi in length. The segment consists of two H-frame double circuit and one H-frame single circuit structures accommodating 69-kV line 700, 230-kV lines 352 and 712, future 230-kV line 353, and a future 138-kV or 230-kV

line.Segment N to O (Fig. 8.2-26) is 0.22 mi long and consists of one H-frame tower accommodating 230-kV line 352 and one future 230-kV

line.Segment O to P runs for 1.67 mi parallel to the right-of-way of the Illinois Central Gulf Railroad and State Highway 19. It accommodates one single-pole structure for 230-kV line 352 and

one future 230-kV line (Fig. 8.2-27 and 8.2-28). Segment P to Q is 5.68 mi long, runs parallel to the Illinois Central Gulf Railroad and State Highway 19, and terminates at Point Q, the Jaguar Bulk Substation. The right-of-way accommodates 230-kV line 352, which becomes 230-kV line 351, and a future 230-kV line on a one-pole tower structure (Fig. 8.2-29

through 8.2-31).

Route IIIRoute III extends 27.2 mi from the Fancy Point Substation to the McKnight Switching Station, and consists of an estimated 132 500-

kV lattice steel towers accommodating 500-kV line RBS USAR 8.2-13 August 1987 752. These towers can also accommodate either one or two 230-kV underbuild circuits. Segment A to R starts at the substation and runs east-southeast 2.21 mi to Point R. The segment carries the 500-kV line 752 on a steel lattice tower with provisions for two future 230-kV

underbuild lines (Fig. 8.2-32). Segment R to S is 2.5 mi long, zigzagging northeast and east alongside of a pipeline right-of-way. The right-of-way accommodates the 500-kV line 752 with provisions for two future

230-kV underbuild lines (Fig. 8.2-33). Segment S to T is 8.0 mi in length and consists of lattice steel towers accommodating 500-kV line 752 with provisions for the future addition of two 230-kV underbuild lines, as shown on

Fig. 8.2-34. Segment T to U is 14.51 mi long and follows a railroad right-of-way. This segment consists of a lattice steel tower accommodating 500-kV line 752 with provisions for the future

addition of two 230-kV underbuild lines (Fig. 8.2-35).

8.2.1.1.3 Summary

All features of the offsite power supply are designed to provide maximum practical reliability and redundancy in servicing the station safety load groups. Compliance with GDC 17 is demonstrated by supplying the substation with offsite ac power by means of two 500-kV and four 230-kV physically independent circuits along two separate rights-of-way. Furthermore, the offsite power sources to the preferred station service transformers are then brought in by two physically independent circuits from this substation. Physical separation, the breaker-and-a-half switching configuration, redundant substation protection systems, and transmission system are designed on load flow and stability studies so as to minimize simultaneous failure

of all offsite power sources.8.2.1.2 Compliance with Design Criteria and Standards 8.2.1.2.1 General Design Criteria

Criterion 17The offsite power system conforms to the requirements of this criterion as follows.

RBS USAR Revision 16 8.2-14 March 2003 Two physically and electrically independent 230-kV circuits, providing two sources of power, are brought into the plant as

shown in Fig. 8.1-4 and 8.2-2. 16Either of the two 230-kV circuits provides sufficient offsite capacity and capability to ensure operation of all safety-related loads for the unit following a design basis accident with loss of normal (generator) power supply. With offsite power available, the standby 4.16-kV buses 1ENS*SWG1A and 1ENS*SWG1B are energized

at all times, and are unaffected by loss of the normal (generator) power supply.

16The normal 4.16-kV swing bus 1NNS-SWG1C, which has a normally closed tie to the standby 4.16-kV bus 1E22*S004, has access to the preferred sources via either normal 4.16-kV bus 1NNS-SWG1A or

1NNS-SWG1B upon loss of normal (generator) power supply. 8.2.1.2.2 Regulatory Guides

Regulatory Guide 1.32Conformance of the offsite power system with specific requirements delineated in Regulatory Guide 1.32 is as follows.

Two circuits from the transmission network are available to the safety systems. Offsite preferred power circuits are connected via normally closed breakers to standby 4.16-kV buses 1ENS*SWG1A and 1ENS*SWG1B at all times. Loss of normal plant auxiliary

supply does not influence or affect the tie circuits of standby

4.16-kV buses 1ENS*SWG1A and 1ENS*SWG1B from the offsite sources. 16 Standby 4.16-kV bus 1E22*S004 is fed from NNS-SWGIC that can be fed from one of the two normal 4.16-kV buses INNS-SWG1A or INNS-SWG1B, which provides access (Section 8.3.1.1.3) to one of the offsite circuits (Fig. 8.1-4), via the preferred station service

transformers, IRTX-XSRIC or IRTX-XSRID, respectively.

168.2.1.2.3 IEEE Standards IEEE Standard 308The offsite power system conforms to the requirements of this standard (Fig. 8.1-3 and 8.1-4). Requirements of Section 5.2.3 of IEEE Standard 308 are met by having two physically and electrically independent, and

continuously available circuits from the transmission RBS USAR Revision 8 8.2-15 August 1996 network to the Class 1E power system. Each of these circuits is capable of starting and operating all safety-related loads and is

monitored in the main control room to verify its availability. 8.2.1.2.4 Additional Standards

National Electrical Safety Code (NESC) - 1977The offsite power system meets or exceeds the NESC requirements for a high density transmission system, Grade B. 8.2.1.3 Testing, Quality Assurance, and System Operability Surveillance Tests and InspectionsThe preoperational and initial startup test programs for the preferred power system is in accordance with Regulatory Guides 1.41 and 1.68 and GDC 1. The test program capabilities

consider GDC 18 and 21 as discussed in Section 3.1.2. During the preoperational stage, all components of the preferred power system are installed, tested, and inspected to demonstrate that all components are correct and properly mounted. All connections are verified as being correct and continuous, and all components as operational. All metering and protective devices

are properly calibrated and adjusted. These tests are described

in Section 14. Following satisfactory checkout of all components of a system as previously described, the initial system tests are performed according to the technical specifications with all components installed. The initial system tests include operational tests conducted to demonstrate that the equipment operates within

design limits and that the system is operational and meets its

performance specifications. 8 The technical specifications/requirements include in-service test and surveillance requirements for the preferred power system following the preoperational and initial system tests and inspections. The particular tests and the frequency of these tests depend upon the specific components installed, their function and environment. These tests are directed at detecting deterioration of the system toward an unacceptable condition and

demonstrating that standby components are operable.

8 RBS USAR Revision 16 8.2-16 March 2003 Circuit breakers and associated devices can be tested when their associated loads or systems are shut down or not in service.

Protective relays are tested under a simulated overload or fault condition, and their calibration is verified. The breaker opening and closing can also be demonstrated. Availability of

power is indicated by breaker position lights. The capability of the preferred power system to transmit sufficient energy to start and operate all required safety-

related loads is confirmed during periodic tests.

These tests also confirm the capability of the supply breakers to operate and transmit the required energy upon receipt of a

control input. These tests are performed at scheduled intervals and verify the ability of the preferred power system to furnish electrical energy for the shutdown of the plant and for the operation of

safety-related systems and engineered safety features.

Quality AssuranceQuality Assurance for the offsite power system is based on industry standards applicable to normal systems. It considers IEEE 336 and Regulatory Guide 1.30, where applicable, to non-Class 1E systems, to meet GDC 1 for equipment

requirements.

System Operability Surveillance16 Surveillance and status of the offsite power system operability are provided by automatic system indication in the main control room. A panel located in front of the principal plant control

console provides a positive indication of breaker positions for the offsite switchyard. Inoperability of offsite power supplies

either by event or deliberate action is annunciated to alert main control room operators to anomalies on the system grid.

Additionally, main control room operators have voice

communication systems to contact the S outhwest-Transmission Operation Center to ascertain system grid status.

16Offsite Power System Monitoring and Surveillance5 The transmission lines of GSU are inspected periodically by aerial patrol.

5 RBS USAR 8.2-17 August 1987 Routine maintenance of substation batteries includes a weekly visual inspection of charge rate and voltage level and a quarterly test of the batteries' ability to maintain voltage

under normal station load. Routine maintenance on power circuit breakers is performed as required to verify that all design criteria for operation are not

exceeded.Control and protective breakers are separated to the maximum extent possible to ensure that failure of any item does not

impair system protection.

8.2.2 Analysis

8.2.2.1 Availability Considerations The 500-kV and 230-kV transmission lines and their associated structures, interconnecting the substation with the system, are

designed to withstand the environmental loading conditions for the area with regard to wind, temperature, lightning, and

flooding.The transmission lines approach the substation on separate rights-of-way on the southeast and southwest sides of the substation. Due to this separation, failure of one line on one

right-of-way does not cause failure of another line on the second

right-of-way.Two independent and redundant transmission lines are provided as offsite power sources for the power plant safety load groups which, as shown in Section 8.3, remain independent down to the lowest voltage level of distribution. These 230-kV sources supply the two 4.16-kV preferred transformers as shown in

Fig. 8.1-6. The 230-kV bays have a breaker-and-a-half configuration with breaker failure backup protection. Substation reliability and

operating flexibility are achieved as follows: 1. Any transmission line can be cleared under normal or fault conditions without affecting any other

transmission line. 2. Any system circuit breaker can be isolated for maintenance without interrupting the power or

protection to any circuit.

RBS USAR Revision 16 8.2-18 March 2003 3. Short circuits on a section of a bus are isolated without interrupting service to any circuit other than

that connected to the faulted bus section. The two independent circuits from the substation to the preferred transformers are routed separately as shown in Fig. 8.2-1. Due to this separation, a failure of one circuit does not cause the

failure of the other circuit. Therefore, these two circuits provide separate and redundant sources to safety load groups.

While it is improbable that all transmission lines could be out of service simultaneously, such an event would not jeopardize a safe shutdown of the station because the onsite standby diesel

generators would be able to supply the necessary power to systems required for safe shutdown or LOCA. The onsite power system, including automatic startup and load sequencing, is described in

Section 8.3. 16 With any single line in service under its design condition of operation, sufficient offsite power would be available to handle

a LOCA and safe shutdown of the unit.

16Outage data on the 230-kV and 500-kV lines in GSU transmission of current experience is given in Tables 8.2-1, 8.2-2, 8.2-4, and

8.2-5.8.2.2.2 Stability Considerations The design and operation of interconnected power systems must be such that they remain stable following severe faults. This is essential to avoid widespread or cascading interruptions to

service, and requires that various stability studies be carried out using mathematical models for the components of electrical

power systems. 11A transient stability study (analysis of conditions within 1 sec after the fault) in compliance with the criteria of the Southwest Power Pool Coordination Council, which is comparable with Southeastern Electric Reliability Council criteria, was performed on River Bend Station Unit 1 using the 1984 summer peak as the base case. The generators were represented as constant voltages behind transient reactance, with no exciter-regulator and no turbine governor, so that conservative results were obtained.

Studies have also been performed (including consideration of

regulation, excitation, and governor action) which verify that the system is dynamically stable. Stability of the interconnected utilities, when Unit 1 goes online, was

investigated under the following conditions:

11 RBS USAR 8.2-19 August 1987 1. Three-phase fault on GSU's Fancy Point Substation 230-kV bus, with a subsequent clearing of the fault in 6

cycles and tripping of River Bend Station Unit 1. 2. Three-phase fault on CEPCO's Big Cajun 500-kV bus, with a subsequent clearing of the fault in 4.5 cycles and

tripping of Big Cajun Unit No. 3. 3. Three-phase fault on Grand Gulf Nuclear Station 500-kV bus, with a subsequent clearing of the fault in 4.5 cycles and tripping of Grand Gulf Unit No. 2

(1,250 MW). 4. Three-phase fault on Arkansas Nuclear One 500-kV bus, with a subsequent clearing of the fault in 4.5 cycles and tripping of Arkansas Nuclear One Unit No. 2

(950 MW). 5. Three-phase fault on Tennessee Valley Authority's Brown's Ferry Station 500-kV bus, with a subsequent clearing of the fault in 4.5 cycles and tripping of

Brown's Ferry Station Unit No. 3 (1,050 MW). 6. Three-phase fault on GSU's Willow Glen 230-kV bus, with a subsequent clearing of the fault in 6 cycles and

tripping of Willow Glen Unit No. 4 (540 MW). 7. Three-phase fault on the 230-kV line from the Fancy Point Substation to Enjay at the River Bend Station

end, with a subsequent opening of the line at both ends

in 6 cycles. 8. Three-phase fault on the 230-kV line from the Fancy Point Substation to Port Hudson at the River Bend Station end, with a subsequent opening of the line at

both ends in 6 cycles. 9. Three-phase fault on the 230-kV line from the Fancy Point Substation to Cajun No. 1 at the River Bend

Station end, with a subsequent clearing of the line at

both ends in 6 cycles. 10. Three-phase fault on the 500-kV line from the Fancy Point Substation to Big Cajun at the River Bend Station end, with a subsequent clearing of the line at both

ends in 4 cycles. 11. Three-phase fault on the 500-kV line from the Fancy Point Substation to McKnight at the River Bend RBS USAR 8.2-20 August 1987 Station end, with a subsequent clearing of the line at both ends in 4 cycles. 12. Three-phase fault on the 230-kV line from the Fancy Point Substation to Enjay at the River Bend Station

end, with a subsequent clearing of the Enjay end in 6

cycles and the Fancy Point Substation end in 12 cycles (stuck breaker). 13. Three-phase fault on the 230-kV line from the Fancy Point Substation to Port Hudson at the River Bend Station end, with a subsequent clearing of the Port

Hudson end in 6 cycles and the River Bend Station end

in 12 cycles (stuck breaker). 14. Three-phase fault on GSU's Enjay 230-kV bus, with a subsequent clearing of the fault in 6 cycles and

tripping of 160 MW of load. 15. Three-phase fault on GSU's Esso 230-kV bus, with a subsequent clearing of the fault in 6 cycles and

tripping of 350 MW of load. The listed cases are conservative with respect to other unlisted less severe faults. Therefore a fault of any kind (loss of the River Bend Station Unit 1, loss of critical loads, loss of EHV

transmission lines, or loss of a large unit inside GSU's system as well as neighboring systems) with successful clearing does not

cause system instability or result in loss of offsite power to safety-related systems. In addition, load flow contingency analyses (Table 8.2-3) show that any line or 500 to 230-kV transformer outage in the Fancy Point Substation does not result

in loss of offsite power supply.Physical separation of the 230-kV offsite power sources, substation protection, redundancy, and transmission system design

based on load flow and stability analysis minimizes the possibility of simultaneous failure of power sources (normal station service supply, preferred station service supply, and

standby ac diesel generators).

This complies with the last paragraph of GDC 17.

RBSUSAR8.3-1August19878.3ONSITEPOWERSYSTEMS8.3.1ACPowerSystems 8.3.1.1Description 8.3.1.1.1General TheonsiteacpowersystemsforRiverBendStationarethosesystemswhichincludeelectricalequipmentandconnections requiredtodistributepowertostationauxiliariesandservice loadsduringallmodesofplantoperation.Theirobjectiveisto providereliableacpowerrequiredduringanormalstartup, operation,andshutdown,orduringanemergencyshutdown.Theac powersystemmusthaveadequateindependence,redundancy, capacity,andtestabilitytoensureitscapabilityforperforming thefunctionsrequiredoftheengineeredsafetyfeatures(ESF) andotherreactorprotectionsystems.Theonsiteelectricalpowersystems(Fig.8.1-4,8.1-6,8.3-1,and8.3-2)extendfromtheonsiteterminationofincominglines uptoandincludingtheelectricalpowerutilizationdevices.

Theseconsistofpowersources(networkinterconnections,onsite standbypowersourcesandtheirauxiliaries,uninterruptible powersources,andbatterysystems),distributionequipment (transformers,circuitbreakers,buses,andinterconnecting cables),instrumentationandcontrols(surveillance instrumentation,protectivecircuitry,andcontrolcircuitry),

andutilizationdevices(motors,solenoids,andheaters).ThephysicalarrangementoftheonsiteelectricalsafetysystemsisdesignedtopreservetheindependenceofredundantESFs.

Physicalseparation,achievedbydistanceorbarriers,is providedbetweensimilarcomponentsofredundantelectrical systems.Inaddition,separationisprovidedbetweenredundant power,instrumentation,andcontrolcircuitryservingorbeing servedfromthesecomponents.Thesafety-relatedelectrical systemsarephysicallyindependentandarelocatedwithinSeismic CategoryIstructuresorportionsofstructuresdesignedtomeet SeismicCategoryIcriteria.Thecontinuityandintegrityofloadfunctionsaremaintainedbyredundantequipmentsuppliedfromseparatesourcesviaseparate cable,cabletray,andconduitsystems.Transformersaresizedforanticipatedmaximumnormalloadplusthosenormalloadswhichmaybetransferredtothemby RBSUSAR8.3-2August1987theswing-busorsectionsofsplit-busunitsubstationloadcenters,byclosureofthetiebreakers.Thesetransformersare notintendedtosupporttotalconnectedload.Motorsaresized tocarryfullloadwithoutencroachmentontheservicefactor margin,and"runout"overloads,suchasthosecausedbybreaks inpipesdownstreamfrompumps,withoutexceedingtheservice factorload.Thedieselgeneratorsaresizedtoacceptfull standbyrequirementsandtoensurefrequencyandvoltage stabilityduringstartingperiodsinaccordancewithRegulatory Guide1.9,exceptfortheHPCSdieselwhichisdescribedin Section8.3.1.2.2.2.Motorsaresizedforanticipatedmaximumloadatagivenspeedwithconsiderationgiventotorquerequirements.Motorinsulation ischosenbytakingintoconsiderationtheenvironmentinwhich themotoristooperate.Theseconsiderationsincludebutare notlimitedtoambienttemperature,humidity,radiationlevel, seismicrequirements,andvoltagelevelofoperation.Theinterruptingcapacityofswitchgear,loadcenters,motorcontrolcenters,anddistributionpanelsisbaseduponstudiesof theelectricalsystem.Thesestudiesconsider,asaminimum,the sizeoftheconnectedload,motorstartingload,motorstarting current,andsystemandconnectedloadcontributionsunder faultedconditions.8.3.1.1.2SystemsIdentification 8.3.1.1.2.1Safety-RelatedSystemsandIdentification TheseClass1Eacpowersystemsofthenuclearplantprovidefunctionsassociatedwithmitigatingtheeffectsofaccidentsor providingforsafeplantshutdown.Thesesystemsaredivided intothreephysicallyandelectricallyindependentdivisions whichareidentifiedbydistinctmeans.Thethreedivisionsare identifiedasfollows:DivisionI-RedDivisionII-Blue DivisionIII-OrangeSeeSection8.3.1.3foradditionalidentificationofthesesafety-relateddivisions.TheClass1Eacpowersystemdivisions andtheirassociatedstandbyswitchgearsandloadcentersare delineatedinFig.8.1-4and8.1-6.

RBSUSAR8.3-3August1987Thesesystemsinclude,butarenotnecessarilylimitedto,the following:1.Emergencycorecoolingsystems(ECCS) 2.Standbyservicewater(SSW)system 3.Standbygastreatmentsystem(SGTS) 4.Coolingsystemsa.Maincontrolroomair-conditioning b.Standbyswitchgearandstandbybatteryroomsventilationandcoolingc.Safeguardequipmentintheauxiliarybuildingventilationd.Standbydieselgeneratorrooms ventilation5.Containmentandreactorvesselisolationcontrolsystem(CRVICS)6.Standbylightingsystem 7.InstrumentationandcontrolfortheRPSandESF functions.LoadsconnectedtotheseClass1Esafety-relatedsystemsarelistedinTable8.3-1.8.3.1.1.2.2Nonsafety-RelatedPowerGenerationSystems Thesesystemsofthenuclearplantarethosewhicharenotessentialforsafeshutdown.Electricalfailureofthese systemscannotresultinthereleaseorfailuretominimize releaseofradioactivematerial.Thesenormalnon-Class1Eac systemsarenonsafety-relatedandthereforenondivisional.They areidentifiedasbeingpartoftheblacksystemorarenotgiven coloridentificationasdescribedinSection8.3.1.3.These systemsinclude,butarenotnecessarilylimitedto,the

following:1.Maincondensatesystem 2.Reactorfeedwatersystem 3.Condensatemakeupsystem RBS USAR Revision 22 8.3-4 6 4. Turbine plant component cooling water system

5. Reactor plant component cooling water system

6. Plant ventilation system

7. Normal service water system

8. Circulating water system

9. Reactor water cleanup system

10. Service water cooling system.

6 8.3.1.1.3 Power Supplies and Buses

8.3.1.1.3.1 Station Service Transformers 13 7 The normal ac power supply can provide electrical power for all station auxiliary loads when the main generator is operating.

It consists of three normal station service transformers 1STX-X NS1A, 1STX-XNS1B and 1STX-XNS1C, electric power through STX-XNS1C is not used, energized by isolated phase bus duct from the generator

terminals, as shown in Fig. 8.1-4.

13 6 4 The preferred ac power supply can provide for all station auxiliary loads. This includes the maximum operational combination of full load power, startup power, hot standby maintenance power, shutdown power, and the safety-related loads.

Preferred power is taken from two physically and electrically independent 230-kV lines originating in the onsite 230-kV substation. The 230-kV line terminating at transformer yard 1 energizes transformers 1RTX-XSR1E and 1RTX-XSR1C. The 230-kV line

terminating at the transformer yard 2A energizes transformers 1RTX-XSR1F and 1RTX-XSR1D. These preferred station service

transformers have the following ratings:

7 1. 1RTX-XSR1E 230-13.8 KV, 51/68/85 MVA OA/FOA/FOA

2. 1RTX-XSR1F 230-13.8 kV, 51/68/85 MVA OA/FOA/FOA

3. 1RTX-XSR1C and 1RTX-XSR1D, 230-4.16 kV, 10/12.5 MVA, OA/FA 4 6 RBSUSARRevision78.3-4aJanuary1995Thesecondariesofnormalandpreferredstationservicetransformersareroutedintotheplantviacablesrunin reinforcedconcreteductlinesandcabletrayswithintheplantto theirassociatedmediumvoltageswitchgearbusesassubsequently

described.

7 RBS USARRevision68.3-4bAugust1993THISPAGELEFTINTENTIONALLYBLANK RBS USAR Revision 22 8.3-5 8.3.1.1.3.2 13.8-kV Systems (750-MVA Interrupting Capability) 7 6 4 RBS has two independent 13.8-kV buses, 1NPS-SWG1A and 1NPS-SWG1B, supporting most of the station auxiliary motor and transformer loads. Each bus supports half the load and has a manually

controlled air circuit breaker (ACB) for access to its normal

source transformers, 1STX-SNX1A and 1STX-XNS1B respectively, and an automatically or manually controlled ACB for access to its preferred source transformers 1RTX-XSR1E and 1RTX-XSR1F, respectively. The 13.8-kV bus 1NPS-SWG1A takes preferred power from transformer 1RTX-XSR1E located at transformer yard 1, while 13.8-kV bus 1NPS-SWG1B takes preferred power from transformer

1RTX-XSR1F located at transformer yard 2A.

4 6 7 Opening the normal supply breaker initiates closing the preferred supply breaker, subject to the following restrictions which

prevent the breaker from closing:

1. Overcurrent or ground fault trip of the normal breaker

2. Manual trip of the normal breaker

3. Loss of voltage of the preferred supply

4. Preferred supply breaker locked-out. 7 A fast automatic transfer scheme and a slow automatic transfer scheme are provided. Unit protective relays initiate opening the normal supply breaker. Time delay contacts from the unit protective relays will block fast transfer if the transfer does not take place within 10 cycles. Manually opening the main

generator output breakers at Fancy Point and/or from the Main Control Room will also block a fast transfer. If the fast

transfer is unsuccessful, all motor breakers and normal supply breakers are automatically tripped. The slow transfer scheme is then initiated and permitted only when residual voltage on the

bus reaches 25 percent or less of the rated voltage.

Return to the normal supply after an automatic throwover can only be done manually. Normal and preferred supply breakers are paralleled for a short period of time during manual throwover.

During manual throwover, the plant operator closes the normal supply breaker and immediately opens the preferred supply breaker. Closing both breakers alarms after a short time delay

in the main control room.

7 RBS USAR Revision 20 8.3-6Offsitepowerenergizingstandby4.16-kVbusesviathepreferredstationservicetransformersarenotjeopardizedduringmanual throwover.Boththenormalandpreferredsupplybreakerstothe normal4.16-kVbuseseffectivelyisolatefaultsonthenormalbus toprotecttheoffsitesourcesofpowertothestandby4.16-kV

buses.

The13.8-kVfeedersfromseparatesourcesareroutedtothe followingperipheralareas,asshowninFig.8.1-6:1.Coolingtowerandwatertreatmentareas-Fourfeeders,twooneach13.8-kVbus,areusedtoservicethesix double-endednormal480-Vloadcenters.Feeder1NPS-ACB06from13.8-kVbus1NPS-SWG1Aprovidespowertotwo 1,000/1,150-kVAtransformers,1NJS-X2Eand1NJS-X2G,at coolingtowers1Band1Dandone500-kVAtransformer, 1NJS-X3A,attheclarifierarea.Thesecondfeeder 1NPS-ACB05,from13.8-kVbus1NPS-SWG1Aprovidespower totwo1,000/1,150-kVAtransformers,1NJS-X2Aand1NJS-X2C,atcoolingtowers1Aand1Candone750-kVA transformer1NJS-X3Catthehypochloritearea.Feeder 1NPS-ACB21from13.8-kVbus1NPS-SWG1Bprovidespower totwo1000/1150-kVAtransformers,1NJS-X2Fand1NJS-X2H,atcoolingtowers1Band1Dandone500-kVA transformer,1NJS-X3B,attheclarifierarea.The secondfeeder1NPS-ACB22from13.8-kVbus1NPS-SWG1B providespowertotwo1000/1150-kVAtransformers,1NJS-X2Band1NJS-X2D,atcoolingtowers1Aand1Candone 750-kVAtransformer,1NJS-X3D,atthehypochlorite

area.2.Circulatingwaterpumparea-Two13.8-kVfeeders,onefromeach13.8-kVbus,providepowertoa4.16-kVsplit bus.Feeder1NPS-ACB07,from13.8-kVbus1NPS-SWG1A, providespowerto10/12.5-MVAtransformer1STX-XS2A whichisconnectedto4.16-kVbus1NNS-SWG2A.Bus 1NNS-SWG2Asupportstwocirculatingwaterpumpsandtwo servicewaterpumps.Thesecondfeeder1NPS-ACB23, from13.8-kVbus1NPS-SWG1B,providespowerto1 0/1 2.5-MVAtransformer1STX-XS2Bwhichisconnectedto4.16-kV bus1NNS-SWG2B.Bus1NNS-SWG2Bsupportstwo circulatingwaterpumpsandoneservicewaterpump.3.The230-kVand500-kVswitchyardsandthemakeupwaterintakestructure-Two13.8-kVfeeders,onefromeach 13.8-kVbus,providepowertothe230-kVand500-kV switchyardsandtheriveredgemakeup RBS USAR Revision 25 8.3-7 pumps. Feeder 1NPS-ACB10, from 13.8-kV bus 1NPS-SWG1A, is run to disconnecting switch 1YWC-SW2 at the switchyard where it is connected to a 750-kVA

transformer, and then run to 2.5/3.125-MVA transformer 1STX-XS3A feeding 4.16-kV bus 1NNS-SWG3A, and 500-kVA

transformer 1STX-XS4A feeding 480-V motor control center 1NHS-MCC12A. The second feeder 1NPS-ACB26, from 13.8-kV bus 1NPS-SWG1B, is run to disconnecting switch 1YWC-SW1 at the switchyard where it is connected to a 750-kVA transformer, and then run to

2.5/3.125-MVA transformer 1STX-XS3B feeding 4.16-kV bus

1NNS-SWG3B, and 288.5-kVA transformer 1STX-XS4B feeding 480-V motor control center 1NHS-MCC12B.

1 6 4. Service Water Cooling Area - Two 13.8-kV feeders one each from 1NPS-SWG1C and 1NPS-SWG1D provide power to a 4.16-kV split bus. Feeder 1NPS-ACB43 from 1NPS-SWG1C provides power to 7.5 MVA OA transformer 1STX-XS5A which is connected to 1NNS-SWG6A. Bus 1NNS-SWG6A supports two service water cooling pumps and feeder to 1NJS-X4A. The second feeder 1NPS-ACB44 provides power to 7.5 MVA transformer 1STX-XS5B which is connected to 4.16-kV bus 1NNS-SWG6B. Bus 1NNS-SWG6B supports one

service water cooling pump and feeder to 1NJS-X4B.

6 8.3.1.1.3.3 4.16-kV Systems (250-MVA Interrupting Capability) 13 7 Each of the two normal in-station 4.16-kV buses NNS-SWG1A and NNS-SWG1B are fed from either the normal station service transformer STX-XNS1C, which has dual secondary windings, one connected to each bus or from their associated preferred station service transformers, RTX-XSR1C and RTX-XSR1D, respectively. The above transformers have been sized for all load conditions on

buses NNS-SWG1A and NNS-SWG1B.

13 For buses NNS-SWG1A, NNS-SWG1B, and NNS-SWG1C the control logic is identical to that described for buses NPS-SWG1A and NPS-SWG1B, except as noted below for bus NNS-SWG1C and the fast transfer is blocked on the NNS-SWG1A/B bus feeding bus NNS-SWG1C and E22-S004 when HPCS pump, E22-PC001, or the Division III standby service

water pump, SWP-P2C, is running. For bus NNS-SWG1C only, a manual transfer capability is provided. When a sustained

undervoltage on the bus is sensed, all motor circuit breakers are tripped. No automatic transfer of NNS-SWG1C alone is provided, it will fast transfer with NNS-SWG1A or NNS-SWG1B from the normal service transformer to the preferred station service transformer

unless blocked as described above.

7 RBS USARRevision138.3-7aSeptember200013A4.16-kVsplitbusanda4.16-kVswingbusareenergizedfrom thenormal4.16-kVbuses.4.16-kVsplitbuses1NNS-SWG4Aand 1NNS-SWG4Bareconnectedtoprimarynormalbuses1NNS-SWG1Aand 1NNS-SWG1B,respectively.4.16-kVswingbus1NNS-SWG1Cis connectedto1NNS-SWG1Bvianormallyclosedcircuitbreakersand to1NNS-SWG1Avianormallyopencircuitbreakers.

13Therearethreestandby4.16-kVbuses:1ENS*SWG1A,1ENS*SWG1Band 1E22*S004.Buses1ENS*SWG1Aand1ENS*SWG1Bareenergizedfrom thepreferredstationservicetransformers1RTX-XSR1Cand1RTX-XSR1D,respectively.Standbybuses1ENS*SWG1Aand1ENS*SWG1Balso

have manual RBS USARRevision68.3-7bAugust1993THISPAGELEFTINTENTIONALLYBLANK RBSUSARRevision138.3-8September2000accesstonormalprimarybuses1NNS-SWG1Band1NNS-SWG1A,respectively,ifrequiredduringlossofpreferredpower.There isnoautomaticfastorslowtransferfromthepreferred transformerstothenormalbusesforeither1ENS*SWG1Aor 1ENS*SWG1B.Thethirdstandby4.16-kVbus1E22*S004isenergized fromthenormal4.16-kVswingbus1NNS-SWG1C.

7*13Eachofthesestandby4.16-kVbuseshasastandby4.16-kVdiesel generatorcapableofsupportingitsrespectivedesignloadupon lossofpreferredpower.Thedieselgenerator1EGS*EG1Asupports standby4.16-kVbus1ENS*SWG1Aanddieselgenerator1EGS*EG1B supportsstandby4.16-kVbus1ENS*SWG1B.TheHPCSsystemdiesel generator1E22*S001G1Csupportsstandby4.16-kVbus1E22*S004.

Eachstandbydieselgeneratorisphysicallyseparatedfromthe othersandislocatedintheSeismicCategoryIdieselgenerator building.Failureofonedieselwillnotimpedetheoperationof theothertwodieselgenerators.

13Standby4.16-kVbus1ENS*SWG1Aandnormal4.16-kVbus1NNS-SWG1A maybefedfromthepreferredstationservicetransformer1RTX-XSRICsimultaneously.Ifanundervoltageconditionweretooccur concurrentlyonbothbuses,atripsignalwouldbegiventothe normalsupplybreakeron1NNS-SWG1Aandtothemotorfeeder breakersonthatbus.Ifpropervoltageisnotavailable,atrip signalwouldbegiventothepreferredsupplybreakeron 1ENS*SWG1Aandthestandbydieselgeneratorwouldstartandwould energizethestandby4.16-kVbus.Division2equipmentfollows thesameoperation.Reference2providesadescriptionofthe standbybustransfersandtrippingunderlossofpower

conditions.Thestandby4.16-kVstandbybusesareelectricallyindependentandphysicallyisolatedfromoneanother.Theirloadsare redundantasrequiredandconsistofstandbymotorsandstandby 480-Vloadcenters.Anexceptionisthestandbyservicewater system.ThetrainApumpsarepoweredby1ENS*SWG1Aand 1E22*S004(onepumponeachbus).ThetrainBpumpsareboth poweredby1ENS*SWG1B.Dccontrolpowerforthestandby4.16-kV switchgearandfor1NNS-SWG1A,1NNS-SWG1B,and1NNS-SWG1Cis suppliedasshowninTable8.3-8.4.16-kVswitchgearassemblies1NNS-SWG2Aand1NNS-SWG2Batthecirculatingwaterpumpareaand1NNS-SWG3Aand1NNS-SWG3Batthe coolingtowermakeuppumpareaand RBSUSARRevision68.3-9August199361NNS-SWG4Aand1NNS-SWG4Battheradwastebuildingand1NNS-SWG6A and1NNS-SWG6Battheservicewatercoolingswitchgearbuilding areofthesplit-busdesign.Undernormalconditionsthesupply breakeroneachbusisclosedandthebustiebreakerisopen.

Noautomaticclosingofthetiebreakertakesplaceafter trippingeithersupplybreaker.Closingallbreakersisby manualcontrol.Whenthesupplybreakersandbustiebreakeraretobeclosedtoparalleltwosourcesforashortperiodoftime duringthrowover,closingofthelastbreakerissupervisedbya synchronizingcheckrelay.Closureofthefourtiebreakers initiatesanalarm.

68.3.1.1.3.4480-VSystemsAllnormalloadcentersfornonsafety-relatedservicearethesplit-busdesign.Twoloadcentertransformersofeachload centerareenergizedfromnormal13.8-kVbuses1NPS-SWG1Aand 1NPS-SWG1B.Inturn,loadcentertransformerssupplyopposite sidesofthesplitbus.Thesebusescanbeconnectedbyclosing thetiebreaker.Thereisnoautomatictransferbetweenthetwo loadcenter480-Vpowersources.Nointerlocksareprovidedto preventparallelingofthetwoloadcenter480-Vpowersources.

Closingthetwoloadcentersupplymainbreakersandthesplit-bustiebreakerisindicatedinthemaincontrolroom.61NJS-LDC4Aand1NJS-LDC4B480VACload-centersareofthesame splitdesignastheothernon-safetyrelatedloadcenters.

Servicewatercoolingload-centertransformersareenergizedfrom normal4.16-kVbuses1NNS-SWG6Aand1NNS-SWG6B.Inturn,load centertransformerssupplyoppositesidesofthesplitbus.

Thesebusescanbeconnectedbyclosingthetiebreaker.There isnoautomatictransferbetweenthetwoloadcenter480-Vpower sources.Nointerlocksareprovidedtopreventparallelingofthe twoloadcenter480-Vpowersources.Closingthetwoloadcenter supplymainbreakersandthesplit-bustiebreakerisindicated inthemaincontrolroom.

6Thestandby480-Vloadcentersaresingle-endedandhavecircuit breakerswithaninterruptingcapabilityofnotlessthan30,000 ampsymmetrical.Thesestandbyloadcentersarefedfromthe standby4.16-kVbuses.Standby4.16-kVbus1ENS*SWG1Aprovides powerforstandby480-Vloadcenters1EJS*LDC1Aand1EJS*LDC2A.

Standby4.16-kVbus1ENS*SWG1Bprovidespowerforstandby480-V loadcenters1EJS*LDC1Band1EJS*LDC2B.DCcontrolpoweris suppliedasshowninTable8.3-8.Standby480-Vloadcenter loadsareredundant RBSUSARRevision68.3-9aAugust1993andincludestandbymotorsandstandbymotorcontrolcenters.Thereareseveralnormalloadsconnectedtothestandby loadcentersidentifiedinTable8.3-7andwhicharetrippedoff thebusduringaLOCA.Thestandby480-Vloadcentersof DivisionIareelectricallyindependentfromthoseofDivisionII andarephysicallyisolatedfromoneanother.Moldedcasecircuitbreakersofbothnormalandstandbymotorcontrolcentershaveaninterruptingcapabilityof25,000amp symmetrical.StandbymotorcontrolcentersofDivisionIare electricallyindependentandphysicallyisolatedfromthoseof DivisionII.Normalloadsconnectedtothestandbymotorcontrol centersandwhicharetrippedoffthebusduringLOCAare identifiedinTable8.3-7.

RBSUSARRevision68.3-9bAugust1993THISPAGELEFTINTENTIONALLYBLANK RBS USAR Revision 16 8.3-10 March 2003 8.3.1.1.3.5 Low Voltage Systems The instrumentation and control supply system consists of a 125-V dc system (Fig. 8.3-6), 120-V ac safety-related uninterruptible power supply systems (Fig. 8.3-2), 120-V ac normal uninterruptible power supply systems (Fig. 8.3-1), and 120-V ac regulated power supplies. The 125-V dc systems provide dc power

for dc loads, uninterruptible power supplies, backup instrumentation and control, and are described in Section 8.3.2.

The 120-V ac uninterruptible power supplies provide ac power for

security, control, and instrumentation systems for the nonsafety-related and engineered safeguard systems (Section 8.3.1.1.3.7).

The 120-V ac regulated power supplies provide ac power for

instrumentation, security, and communication systems for the

nonsafety-related and engineered safeguard systems. The instrumentation and status indications of Class 1E switchgear aforementioned are described in Section 7. 8.3.1.1.3.6 Standby Electrical Power Systems

The standby electrical power systems are designed to provide redundant sources of onsite ac electric power which are self-

contained within the unit and which are not dependent on the normal and preferred sources of supply. The standby electrical

power systems are capable of supplying ac power for electrical

loads which are required for a safe shutdown of the reactor. 16 The standby system ac distribution buses are rated at 4.16-kV and 480-V. There are three standby 4.16-kV ac buses and four standby 480-V ac load centers. The bus configuration (Fig. 8.1-6) is described in Sections 8.3.1.1.3.3 and 8.3.1.1.3.4. Upon loss of

voltage on associated standby 4.16-kV buses, or a LOCA signal

initiated by an abnormally low water level in the reactor vessel or a high drywell pressure, or a manual start signal, the generators are started and brought up to rated frequency and voltage. If, at this time, the two redundant supply power lines

to the buses are open, the standby generator breakers automatically close on their associated dead buses. The diesel

generators are not automatically connected to their respective

standby 4.16-kV buses if the buses are still connected to either

the preferred or normal station service transformers.

16Unit 1 reactor has three diesel generators: 1EGS*EG1A, 1EGS*EG1B, and 1E22*S001G1C. Diesels 1EGS*EG1A and 1EGS*EG1B are devoted to

safety-related equipment as shown RBS USAR Revision 12 8.3-11 December 1999 in Fig. 8.1-6. Diesel 1E22*S001G1C energizes the HPCS system as described in Section 8.3.1.1.3.6.2. 8.3.1.1.3.6.1 Standby Diesel Generators

8.3.1.1.3.6.1.1 Description Each standby diesel generator is physically independent, located in a building structure designed to withstand earthquakes and to protect the standby diesel generators against tornadoes, floods, hurricanes, and tornado-generated missiles (Section 3.8). Within

the protected structure, each standby diesel generator, including

its associated starting equipment and other auxiliaries, is installed in a separate room of a Seismic Category I building so that an incident at one generator will not physically or electrically involve the others. Each standby diesel generator

is provided with a separate missile-protected combustion air intake, room air intake and discharge, and diesel engine exhaust

opening.Seismic qualification of the standby diesel generators and associated equipment is discussed in Sections 3.9.2.2A and 3.10A.

In addition, the standby diesel generators can provide full rated

load when subjected to extreme atmospheric conditions, e.g., due

to a hurricane or tornado. The probability of a tornado striking a point on the site is low, about once in 3,415 yrs (Section 2.3.1.2.4).

Each standby diesel generator is provided with an independent fuel oil system consisting of a day tank with fuel capacity for 1-hr minimum operation at required load, and one 100 percent capacity Class 1E fuel oil transfer pump for automatically filling the day tank from its respective storage tank. One fuel oil storage tank for each standby diesel generator supplies fuel for continuous operation at its rated capacity for 7 days (Section 9.5.4). 12Each standby diesel generator unit is provided with two independent and redundant air starting systems with separately

powered air compressors to furnish air for automatic and manual starting and for control air. The starting systems for each

standby diesel generator includes electrically driven

compressors, primary air tanks, reserve air tanks, and necessary gears and valves for cranking the engine. The two starting

systems (the HPCS diesel's air compressors are described in Section 8.3.1.1.3.6.2) are arranged so that failure of one will not jeopardize proper operation of the other. Each train of the starting system is capable of at least eight cranking cycles

without the assistance of 12 RBS USAR Revision 16 8.3-12 March 2003 16outside power. The time required by each air compressor to recharge its tank from minimum starting air pressure to operating air pressure is approximately 30 minutes. Each standby diesel

engine is provided with cooling by means of a shell and tube heat exchanger cooled by water from the SSW system. Each generator is a self-cooled air-ventilated unit. All necessary auxiliaries

directly associated with each standby diesel-generator unit, such as ventilating fans, battery chargers, fuel oil transfer pump, etc, are powered from their associated standby buses. Electrical

power for starting and control is supplied from the 125-V dc

system associated with that generator.

1611 The standby diesels for 1EGS*EG1A and 1EGS*EG1B are Transamerica Delaval, Inc. type DSR 48 and provide 4869 bhp in continuous duty. However, special requirements are imposed by the Facility Operating License for continuous operation of these two standby diesels above 4197 bhp (3130 KW). The synchronous generators

were manufactured by Parsons Peebles Electric Products, Inc.

11The rating of each standby diesel generator is determined from plant design and power requirements and has the capability to ensure proper starting and operation of all required motor loads without excessive frequency or voltage drop. The rating of each of the standby diesel generators is adequate for the maximum required coincident loads during the unit design basis accident (DBA) in accordance with Regulatory Guide 1.9, except for the HPCS diesel. The philosophy applicable to the sizing of the HPCS

diesel is defined in Section 8.3.1.1.3.6.2.

The nameplate ratings of the standby diesel generator sets are as follows: Standby Standby Diesel Generator Diesel Generator Time 1EGS*EG1A 1EGS*EG1B (hr) 3,500 kW 3,500 kW 8,760 3,850 kW 3,850 kW 2 The 8,760-hr rating is on continuous duty under normal maintenance.

The standby diesel generators are specified to provide their rated output for combustion air temperatures ranging from 2°F to

110°F.No derating is required for ambient atmospheric pressures down to 20.58 inches Hg - absolute (10.1 psia). Humidity RBS USAR Revision 16 8.3-13 March 2003 extremes are not expected to affect the operation of the standby diesel generators since the intake air is compressed and heated

in the turbochargers prior to entering the engines. 168The standby generator and the 4.16-kV preferred station service system are manually synchronized during periodic testing or upon restoration of preferred power. A synchronous check relay is

provided to prevent breaker closure during synchronizing operations unless the busses are synchronized within the tolerances of the relay. A synchronous check relay is provided

to prevent breaker closure during synchronizing operations unless the busses are synchronized within the tolerances of the relay.

If any safety-related switching equipment fails to operate

automatically, manual operation is possible, remotely in the main control room or at the standby diesel generator control room.

Except for sensors and other equipment that must be directly mounted on the engine or associated piping, the controls and

monitoring instrumentation are installed on free-standing floor-

mounted panels located in a vibration-free floor area.

8 168.3.1.1.3.6.1.2 Starting and Loading 13The standby diesel generator sets are designed for independent operation, but they may be operated in parallel with the plant auxiliary system for exercising and test purposes. Standby buses 1ENS*SWG1A and 1ENS*SWG1B are normally continuously energized from the preferred station service transformers. Standby bus

1E22*S004 is also normally continuously energized from the preferred station service system. The standby diesel generators are started upon receipt of an undervoltage signal from the

standby bus source, upon receipt of a LOCA signal or on manual

signal. The automatic transfer of each standby bus to its standby generator is done only on loss of voltage measured on the standby 4.16-kV bus. Transfer is accomplished by opening both the normal

and preferred station service transformer supply circuit breakers

and closing the standby generator's circuit breaker when the

generator is at proper voltage and frequency.

13Low voltage on a standby bus automatically disconnects all 4.16-kV motor loads on the bus. Sequencing of loads supplied from the standby diesel generators is required to prevent exceeding the

motor starting and load pickup capability of the standby diesel generator. Provisions are made for automatic sequencing of all loads in accordance with Table 8.3-2. Other loads may be

connected by the station operators (by manually controlled breakers) when load conditions permit. There is no automatic load shedding of the standby 4.16-kV buses when power is

furnished by the standby diesel generator.

RBS USAR Revision 22 8.3-14 The load sequencing control for the onsite and offsite power sources for River Bend Station utilizes individual timers and

permissive circuitry for individual feeder breakers being sequenced on standby buses. Although there is a logic which ties

the operation of the entire load sequencing scheme together, failure of one or more breaker timers or permissive circuits to

operate does not prevent other breaker timers and permissives from performing their intended functions. Timers and permissives are located in qualified switchgear and relay panel enclosures for the breakers they control. There are no credible sneak

circuits or common failure modes in the sequencing design that could render either the onsite or offsite power sources

unavailable.

An emergency demand start signal overrides all other operating

modes including test and returns control of the diesel-generator

unit to the automatic load sequencing system.

The standby diesel generator incorporates two modes of control, OPERATIONAL and MAINTENANCE.

a. In the OPERATIONAL mode the diesel starts and comes up to speed when either of the following conditions is present:

1) A MANUAL START SIGNAL generated from the local control panel and the units entire protective system is reset.

A Manual Start Signal, starts the diesel generator in the "slow start" mode of operation. This "slow start,"

which is recommended by the manufacturer, extends the

starting time of the diesel to minimize the aging

effects associated with fast starts. 16 2) An EMERGENCY START SIGNAL generated by either a LOCA signal or a sustained bus undervoltage or by depressing

emergency START push button in the main control room or

by pressing the emergency start button on the control

panel. The emergency start overrides all conditions and returns the unit to rated speed. (Refer to Section 3.1.1.4.1) Emergency start overrides all conditions such as: Slow Start Manual Running Test Tripping on fault conditions except for the following: 1.Overspeed 2.Generator Differential 3.Lube and Jacket Water h igh temperature trips unless the emergency start comes from a LOCA signal or the trips are bypassed by a local control switch (Applicable to EGS-EG1A and EGS-EG1B ONLY)

. 16 b. In the MAINTENANCE mode only the engine ROLL pushbutton on the local panel is operative. This feature permits cranking

the diesel without effecting a start.

c. The standby diesel generators may be tested while in the operational mode by manually starting the engines and

manually closing the circuit breakers connecting RBS USAR Revision 16 8.3-15 March 2003 the standby diesel generators to the bus. In this manner, the standby diesel generators can be tested under load while

in parallel with the grid. Should the grid go to an undervoltage or underfrequency condition, the circuit breakers in the Fancy Point

Substation trip and deenergize the circuit feeding the preferred station service transformers. The pilot wire

system also initiates a trip of the 4.16-kV circuit breaker

between the preferred station service transformer and the bus. With the preferred or alternate supply breakers in the open position, the generator setting would switch from the

parallel operation mode to the isochronous mode, and the

standby diesel generator picks up the entire load of the

standby 4.16-kV bus sequentially. The standby diesel generators are capable of running unloaded for 7 days without degrading the performance or reliability of the engine. The manufacturer has demonstrated this

capability with a special no load endurance test. 8.3.1.1.3.6.2 High Pressure Core Spray Power Supply System

8.3.1.1.3.6.2.1 Description Fig. 8.3-3 shows the HPCS power system (Division III) simplified one-line diagram electrical arrangement, power distribution, protective relaying, and instrumentation for the HPCS power

system.The HPCS power supply system is self-contained except for the initiation signal source and access to the preferred source of offsite power through the plant ac power distribution system. It has a dedicated diesel generator, 1E22*S001G1C and is operable as an isolated system independent of electrical connection to any

other system. 16The HPCS diesel 1E22*S001G1C is a Stewart and Stevenson EMD 20645-E4, 20-cylinder vee type. It provides 3600 bhp in continuous duty. The synchronous generator was manufactured by

Ideal. This SM-100 model has a 2,000-hr rating of 2850 kW.

16Seismic qualification of the HPCS diesel generator and associated equipment is discussed in Section 3.9.2.2B and 3.10B. In addition, the HPCS diesel generator can provide full-rated load when subjected to extreme atmospheric conditions. No derating is

required for operation in RBSUSARRevision88.3-16August1996ambienttemperaturesupto120°F,arelativehumidityof90percent,andanatmosphericpressuredownto28.25inchesHg.

Lowcombustionairtemperaturesdonotaffecttheoperabilityof theHPCSdieselgeneratorsincetheintakeairiscompressedand heatedintheturbochargerpriortoenteringtheengine.84Thestandbyauxiliaryequipmentsuchasheatersandbattery chargeraresuppliedfromthesamepowersourceastheHPCS motor.Thenon-safetyrelatedHPCSDGaircompressorsare suppliedfromnon-safetyrelatedpowersources.

84VoltageandfrequencyoftheHPCSdieselgeneratoriscompatiblewiththatavailablefromtheplantacpowersystem.8TheHPCSdieselgeneratorhasthecapabilitytorestorepower quicklytotheHPCSbusintheeventoffsitepowerisunavailable andtoprovideallrequiredpowerforthestartupandoperation oftheHPCSsystem,onestandbyservicewaterpumpmotor,and miscellaneousauxiliariesassociatedwithit.TheHPCSdiesel generatorstartsautomaticallyonaLOCAsignalfromtheplant protectionsystemorundervoltageontheHPCS4.16-kVbus (1E22*S004),andwillbeautomaticallyconnectedtotheHPCSbus whentheplantpreferredacpowersupplyisnotavailable.The failureofthisunitwillnotnegatethecapabilityofother powersources.Thereisnoprovisionforautomaticparalleling oftheHPCSdieselgeneratorwiththeauxiliarypowerorwith standbypowersources.Provisionsformanualparallelingwith normalpowersourcesaremadeforloadingthedieselgenerator duringtheexercisemode.Asynchronouscheckrelayisprovided topreventbreakerclosureduringparallelingunlessthebusses aresynchornizedwithinthetolerancesoftherelay.IfaLOCA signaloccurswhiletheHPCSdieselgeneratorisrunningin parallelwiththenormalbus,thedieselgeneratorbreakerwill automaticallytrip.Atleastoneinterlockisprovidedtoavoid accidentalparalleling.ThereisnosharingoftheHPCSpower systemwithotherstandbydieselgenerators.8TheHPCSpowersystemloadsconsistoftheHPCSpump/motorand associatedauxiliaries,motor-operatedvalves,onestandby servicewaterpump,andmiscellaneousauxiliaryloads.

Table8.3-3showstheDivisionIIIloads.TheHPCSpumpmotorisaGeneralElectric4-kVverticalinductionmotorratedat2500hp.Theverticalpumpwasmanufacturedby theBorg-WarnerByron-JacksonPumpDivision.Itisratedat 5,125gpmwith945ftofheadanditsmotorhasamaximum shaftbhpof2,500at1,780rpm.TheHPCSelectricsystemiscapableofperformingitsfunctionwhensubjectedtotheeffectsofdesignbases RBSUSARRevision88.3-17August1996naturalphenomena.ItisdesignedinaccordancewithSeismicCategoryIandhousedinaSeismicCategoryIstructure.ThedetaileddescriptionofthefueloilstorageandtransfersystemassociatedwiththeHPCSdieselgeneratorunitis describedinSection9.5.4.FuelfortheHPCSdieselengineis providedinaseparatedaytankandinastoragetank.Theday tankpermitsaminimumof1hrofoperationatratedload.The combinedcapacityofthedaytankandthestoragetankpermits theHPCSdieselenginetooperateatcontinuousratedload conditionsforatleast7days.8Theengineairstartingsystemcontainstwocompletesetsof startingcomponents,eitherofwhichiscapableofstartingthe engine.However,tofurtherensurestartingwithinthetime requirements,bothsetsareutilizedsimultaneouslytocrankthe engine.Eachsetofcomponentsconsistsofdualairstart motors,airrelayvalve,solenoidvalve,airreceivers,andair compressorassembly.Bothcompressorsarecapableofautomatic startandstopandarecontrolledbypressureswitchesto maintainrequiredpressureintheairreceivers.Thetwoair startingsystemsareredundant,independent,andarrangedsothat failuretostartinonesystemwillnotjeopardizestartingof thedieselgeneratorbytheothersystem.

8Manualcontrolsareprovidedtopermittheoperatortoselectthemostsuitabledistributionpathfromthepowersupplytothe load.Anautomaticstartsignaloverridestheexercisemode.

Provisionsaremadeforcontrolfromthemaincontrolroomand externaltothemaincontrolroomfromanHPCSdieselgenerator controlpanellocatedexternaltothemaincontrolroominthe dieselgeneratorbuildingasshowninFigure8.3-11.Thecontrol panelincludesfacilitiesforbreakercontrolofincomingfeeder andHPCSgeneratorbreakertogetherwithfrequencymeter, synchroscope,bus,andincomingvoltmetersandenginespeed controldevice.Exceptforsensorsandotherequipmentthatmustbedirectlymountedontheengineorassociatedpiping,thecontrolsand monitoringinstrumentationareinstalledonfree-standingfloor-mountedpanelslocatedinavibration-freefloorarea.ControlpowerfortheHPCSdieselgeneratorunitissuppliedfromitsown125-Vbatterysystem,whichconsistsofa RBS USARRevision 218.3-18battery with its own battery charger. The charger is designedto carry the continuous load in addition to normal battery charging current. Section 8.3.2.2 provides a discussion of the HPCS 125-V dc system. Tables 8.3-3 and 8.3-6 show the HPCS

diesel generator size and the 125-V dc load requirements.8.3.1.1.3.6.2.2 Starting and Loading A loss of normal potential at the HPCS bus is one of the threeinitiating signals which automatically starts the HPCS diesel generator. The other two signals are accident signals of reactor low water level and high drywell pressure which are described in detail in Section 7.3.1. On receipt of a start signal or HPCS supply bus undervoltage, the HPCS diesel

generator will start and accelerate to operating voltage and frequency as standby power supply for the HPCS system. On

reaching rated speed and voltage, the generator is automatically connected to the HPCS bus if ac power is not available at the bus. Once the diesel generator has been energized, the unit will continue to operate until manually deenergized or until the

protective devices of the HPCS diesel generator cause a trip.The HPCS diesel generator is capable of running unloaded for4.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> without degrading the performance or reliability of the engine, after which, it must be run at a minimum of 40

percent of nameplate rating for 30 minutes.The HPCS diesel generator has the capacity to start all motorsas required by the design basis so that the main pump is at rated speed and all required valve operations are completed within the time requirements described in Sections 6.3 and 9.2.7. All HPCS loads associated with the DBA are started

concurrently, except the DG room vent fan, the standby service water pump

, and its associated motor-operated valve 1SWP*MOV40C, which are sequenced to start as noted in Table 8.3-3.

An emergency demand start signal overrides all other operatingmodes including tests and then returns control to the sequencing system. Refer to Section 5 of NEDO 10905 for a description of

control and protection of the HPCS diesel generator.

8.3.1.1.3.7 120-Volt AC Uninterruptible Power Supply System The 120-V ac uninterruptible power supply system suppliescontrol power to vital computer and instrumentation loads for which power interruption must be avoided. These RBS USAR Revision 20 8.3-19 services are necessary for the normal operation of the plant.

Power from the uninterruptible power supplies is free from extraneous voltage spikes, switching surges, and momentary interruptions, and satisfies the voltage and frequency variation limits of the station computers and instrumentation systems. A high degree of power continuity is provided, with the uninterruptible power supply being able to switch automatically between two independent sources of input

power, or to transfer to an independent alternate source of regulated ac power with sufficient speed so the operation of the computer and

instrumentation is not affected. 13 Normally the uninterruptible power supply inverter (Figure 8.3-1 and 8.3-2) receives dc power from a 480-V ac motor control center (MCC) feeding an ac-to-dc rectifier, with a second source of dc power coming from the 125-V dc station battery. Any failure of the MCC feeding the rectifier results in the station battery carrying the uninterruptible power supply load without interruption. Malfunctions of both of the two dc sources of power to the inverter or the inverter itself causes

the static switch to automatically transfer the power source to an independent alternate source fed from a 480-V ac MCC feeder through a

voltage regulating transformer in all uninterruptible power supplies.

1BYS-INV06 furnishes power to DRMS, ERIS, and other support service loads. A make-before-break manual bypass switch enables maintenance, inspection, and testing of the uninterruptible power supply components

to be safely performed while feeding the loads from the alternate

source voltage regulating transformer.

13 15 1 There are a total of eleven uninterruptible power supply systems in the plant.

ENB-INV01A and ENB-INV01A1 are associated with Division I, ENB-INV01B and ENB-INV01B1 are associated with Division II and the

remainder (BYS-INV01A, BYS-INV01B, BYS-INV02, BYS-INV04, BYS-INV06, and IHS-INV01) are connected to normal buses. BYS-INV03 is a

nonsafety-related swing inverter which supplies 120 VAC power to distribution panel. Through switches near the local inverter, BYS-INV03 may be utilized to supply backup power to the loads of BYS-

INV01A or BYS-INV01B.

Either ENB-INV01A (01B) or ENB-INV01A1 (01B1) (but not both simultaneously) may be selected to supply power to VBS-PNL01A (01B) through the use of manual transfer switch VBS-TRS02A (02B). Either unit may be in-service at any given time, with the other unit de-energized and available as a backup. Upon failure of the in-service UPS, the backup unit is energized and placed in service via operation of VBS-TRS02A (02B). This allows a rapid method of in service via operation of VBS-TRS02B. This allows a rapid method of restoring power to the Division I (II) 120 Volt AC Vital Bus in the event of a failure of the in-service UPS. The ac sources for the uninterruptible power supplies associated with the standby systems are derived from the standby diesel generators feeding buses 1ENS*SWG1A and 1ENS*SWG1B.

All uninterruptible power supplies and their associated distribution panels are completely independent (by division). Those panels associated with standby systems serve redundant safety-related

equipment. The distribution 1 15 RBSUSARRevision88.3-20August1996panelscontainfuseddisconnectswitchesforbranchcircuitprotection.Manualorautomaticdevicesforswitchingto interconnecttheredundantsafety-relateduninterruptiblepower suppliesarenotprovided.8.3.1.1.3.8ReactorProtectionSystem(RPS)PowerSystem 8.3.1.1.3.8.1General TheRPSpowersystemisdesignedtoprovidepowertothelogicsystemthatispartofthereactorprotectionsystem.Itprevents auxiliarypowersystemswitchingtransientsfromcausingan inadvertentreactorscramduetoatransientdisturbanceofpower tothereactorscramlogic.TheprincipalelementsoftheRPSpowersystemincludetwohighinertia,alternatingcurrent,motorgeneratorsetsand distributionequipment.Eachmotorgeneratorsetsuppliespowerforthenuclearsteamsupplyshutoffsystem,neutronmonitoringsystem,partsof processradiationmonitoringsystem,andreactorprotectiontrip system.TheRPSpowerisclassifiedasnonessentialbecause failureofthepowersupplycausesareactorscramandisolation.

However,thepowerfeedstoredundantlogicsarephysically separatedbyrunninginseparateconduits.RPSsafety-relatedsignalcables,powercables,andracewaysareidentifiedbynameplatesand/orcolorcodestodistinguishfrom nonsafety-relatedequipmentandtodistinguishbetweenredundant, safety-relatedequipment.RPSsafety-relatedinstrumentpanelsareidentifiedbycolorcodednameplatestodistinguishfromnonsafety-relatedequipment andtodistinguishamongredundant,safety-relatedequipment.RBSprovidesprotectionofRPSbusesAandBfromvoltageandfrequencyanomalieswhichcoulddamageRPScomponentsandthus precludeimproperoperationoftheRPS.Theprotectionis affordedbytheuseofelectricalprotectionassemblies(EPAs) whichareClass1E.TheEPAsprovideredundantprotectiontothe busesbyactingtodisconnectthebusesfromthepowersources notwithindesignspecifications.8TheEPA(Figure7.2-1)consistsofacircuitbreakerwithatrip coilcontrolledbythreeindividualsolidstaterelayswhich senselinevoltageandfrequencyandtripthebreakeropenon8 RBS USAR Revision 25 8.3-21 the conditions of overvoltage, undervoltage, and under-frequency.

Provision is made for setpoint verification, calibration, and

adjustment under administrative control. After tripping, the circuit breaker must be reset manually. Trip setpoints are based on providing 115-V ac, 60-Hz power at the RPS logic cabinets.

The protective circuit functional range is `10 percent of nominal

ac voltage and -5 percent of nominal frequency.

The four EPA enclosures for each RPS bus are mounted on a Seismic Category I structure separately from the motor generator sets and separate from the four EPAs of the other RPS bus. Two EPAs are

installed in series between each of the two RPS motor-generator

sets and the RPS buses and between the auxiliary power sources and RPS buses. Figure 7.2-1 provides an overview of the eight EPA

units and their connections between the power sources and the RPS buses. The EPA is designed as a Class 1E electrical component.

It is designed and fabricated to meet the quality assurance

requirements of 10CFR50 Appendix B.

8.3.1.1.3.8.2 Components

Each of these high inertia motor generator sets has a voltage regulator which is designed to respond to a step load change of 50 percent of rated load with an output voltage change of not more than 15 percent. High inertia is provided by a flywheel.

The inertia is sufficient to maintain the voltage and frequency of generated voltage within 5 percent of the rated values for a minimum of 1 sec following a total loss of power to the drive

motor.

8.3.1.1.3.8.3 Sources

The power to each of the RPS buses is supplied from two 120-V ac

sources. The primary source of power is the motor generator sets. The alternate source of 120-V ac power is Class 1E and

redundant, and consists of a 480-120-V voltage-regulating transformer. The two motor generator sets are supplied from

separate 480-V motor control centers normally energized from the normal station service transformers, and which also are connectable to the preferred station service transformers via the non-Class 1E distribution system. Indicating lights are provided in the main control room to monitor the status of both the motor

generator sets and the instrument buses.

RBS USAR Revision 25 8.3-22 8.3.1.1.3.8.4 Operating Configuration During operation, the reactor protection system buses are energized by their respective motor generator sets. Either motor

generator set can be taken out of service by manually operating

the power source selector switch which disconnects the motor generator set and connects the respective RPS bus to its alternate power source. Only one RPS bus may be placed on alternate power when in Modes 1 OR 2 except for limited emergent plant situations which require both RPS buses to be connected to their alternate supplies for short periods. Alignment of both RPS buses to their alternate supplies is not the normal line up because of increased vulnerability to grid perturbations that could result in inadvertent trip of both divisions of RPS connected loads. Short periods are not to exceed the time required to correct the limited emergent plant situation(s) to restore at least one RPS bus to normal power supply. A loss of power to either motor generator set is monitored in the main control room (white indicating lamp goes off) where the operator, on detecting such a condition, can switch over to the alternate power source. A loss of power to one motor generator set results in a single RPS trip system trip. A persistent loss of electrical power to both motor generator sets (1 sec minimum)

results in a scram. 8.3.1.1.3.9 Adequacy of Electrical Distribution System Voltages 16 Two completely separate schemes of undervoltage protection are provided on the Division I and II Class 1E buses at the 4.16-kV level. The selection of undervoltage and time delay setpoints has been determined from an analysis of the voltage requirements of the Class 1E loads. These setpoints are verified during

surveillance testing.

16 The first undervoltage scheme detects loss of power at the Class 1E buses. This undervoltage setpoint is set below any anticipated transient voltage condition, with a time delay of

approximately 3 seconds. The second level of undervoltage protection is set at approximately 90 percent and utilizes two separate time delays

based on the following conditions:

1.The first time delay is approximately 5 sec, which establishes a sustained degraded voltage condition (i.e., something longer than a motor starting transient).

Following this delay, an alarm in the main control room alerts the operator to the degraded condition.

The subsequent occurrence of a LOCA signal immediately separates the Class 1E distribution system RBS USAR Revision 25 8.3-22a from the offsite power system, starts load shed logic and load sequence timers, starts the diesel generator, and permits auto-close of the diesel generator breaker. 13 2.The second time delay is approximately 60 sec, which ensures that permanently connected Class 1E loads will

not be damaged. Following this time 13 RBSUSAR8.3-23August1987delay,iftheoperatorhasfailedtorestoreadequatevoltages,theClass1Esystemisautomatically separatedfromtheoffsitepowersystem,theloadshed logicandloadsequencetimersstart,andthediesel generatorstartsandpermitsauto-closeofthediesel generatorbreaker.Undervoltageprotectionisaffordedtotheacdistributionsystemdowntoandincludingthe480-Vmotorcontrolcenters(MCCs) level.Thetrippingofthe4.16-kVaircircuitbreakers(ACBs) discussedabovealsoresultsinnovoltageatthe480-Vload centersandMCCswhich,inturn,willcausemotorfeederACBsand contactstoopencircuit.Subsequentenergizationofthe4.16-kV busesbythedieselgeneratorresultsinthere-energizationof MCCmotorloadswiththeclosingoftheircontactsat approximately70percentvoltage.Thevoltagesensorsaredesignedtosatisfythefollowingapplicablerequirements:1.Class1EequipmentisutilizedandisphysicallylocatedatandelectricallyconnectedtotheClass1E

switchgear.2.AnindependentschemeisprovidedforDivisionIandIIoftheClass1Epowersystem.3.Theundervoltageprotectionincludescoincidencelogic(2outof3)onaper-busbasistoprecludespurious tripsoftheoffsitepowersource.4.Thevoltagesensorsautomaticallyinitiatethedisconnectionofoffsitepowersourceswheneverthe voltagesetpointandtimedelaylimitshavebeen

exceeded.5.Capabilityfortestandcalibrationduringpoweroperationisprovided.Undervoltagerelaysettingson theClass1E4.16-kVbusescanbecheckedduringplant operationbytestingonesingle-phaseundervoltage relayatatime.Disconnectingonephaseofthethree-phasesystemdoesnotimpairtheoperationofthe switchgear.Normallyatwo-out-of-threelogic,the removalofonerelayresultsinaneffectiveone-out-of-twologic,i.e.,anundervoltagedetectedbyanyone ofthetworemainingrelaysstillinthecircuitwould initiateanundervoltagetrippingsequence.The removedrelaycanthenbecheckedagainsta RBSUSARRevision68.3-24August1993variablevoltagetestinputtoverifyitsintended setpoint.6.Annunciationisprovidedinthecontrolroombyanybypassesincorporatedinthedesign.TheClass1Ebusloadsheddingschemeautomaticallypreventssheddingduringsequencingoftheemergencyloadstothebus.

Theloadsheddingfeatureisreinstateduponcompletionofthe loadsequencingaction.Thevoltagelevelsatthesafety-relatedbusesareoptimizedforthemaximumandminimumloadconditionsthatareexpected throughouttheanticipatedrangeofvoltagevariationsofthe offsitepowersources.Thetripsettingsselectedarebasedon ananalysisofthevoltageattheterminalsoftheClass1E loads.Theanalysesperformedtodetermineminimumoperating voltagesconsidermaximumunitsteadystateandtransientloads foreventssuchasaunittrip,lossofcoolantaccident, startup,orshutdown,withtheoffsitepowersupply(grid)at minimumanticipatedvoltageandonlytheoffsitesourcebeing consideredavailable.Maximumvoltagesareanalyzedwiththe offsitepowersupplyatmaximumexpectedvoltageconcurrentwith minimumunitloads.1Theanalyticaltechniquesandassumptionsusedinthevoltage analysiswereverifiedbyactualmeasurement.Theverification andtestwereperformedpriortoinitialfull-powerreactor operationonallsourcesofoffsitepowerby:

11.Loadingthestationdistributionbuses,includingallClass1Ebusesdowntothe120/240Vlevel,toatleast 30percent.2.RecordingtheexistinggridandClass1Ebusvoltagesandbusloadingdowntothe120/240Vlevelatsteady stateconditionsandduringthestartingofbotha largeClass1Eandnon-Class1Emotor(not

concurrently).63.Usingtheanalyticaltechniquesandassumptionsofthevoltageanalysisabove,andthemeasuredexistinggrid voltageandbuslosingconditionsrecordedduring conductofthetest,anewsetofvoltagesforallthe Class1Ebusesdowntothe120/240Vlevelwas

calculated.

6 RBS USAR Revision 17 8.3-25 6 4. The analytically derived voltage values were compared against the test results.

6Two completely separate schemes of undervoltage protection are provided on the Division III Class 1E HPCS bus at the 4.16-kV level. The selection of undervoltage and time delay setpoints has been determined from an analysis of the voltage requirements of the Class 1E loads. These setpoints will be verified during the actual system testing. The first and second level

undervoltage protection scheme senses voltage at the incoming

side of the normal supply breaker. 13The first level undervoltage setpoint is set below any anticipated transient voltage condition, with a time delay of

approximately 3 sec.

The second level of undervoltage protection is set at approximately 90 percent of normal voltage and utilizes two

separate time delays based on the following conditions: 1. The first time delay is approximately 5 sec and establishes a sustained degraded voltage condition (i.e., something longer than a motor starting transient). Following this delay, an alarm in the main

control room alerts the operator to the degraded condition. The subsequent occurrence of a LOCA signal immediately separates the Division III HPCS bus from the offsite power system. The Division III HPCS bus

will experience a loss of voltage and the primary

undervoltage relays and control circuit will start load shed logic, start the diesel generator, and permit

auto-close of the diesel generator breaker when the

diesel generator attains its rated speed, voltage, and

frequency.

132. The second time delay is approximately 60 sec and is set to ensure that permanently connected Class 1E loads will not be damaged. Following this time delay, if the operator has failed to restore adequate voltages, the Division III HPCS bus is automatically separated from the offsite power system. The Division III HPCS bus

will experience a loss of voltage and the primary

undervoltage relays and control circuit will start the

load shed logic, start the diesel generator, and permit

auto-close of the diesel generator breaker when the

diesel generator attains its rated speed, voltage, and

frequency.

RBSUSAR8.3-26August1987Undervoltageprotectionisaffordedtotheacdistributionsystemdowntoandincludingthe480-Vmotorcontrolcenter(MCC)level.

Thetrippingofthe4.16-kVoffsitepowersupplycircuitbreaker discussedabovealsoresultsinnovoltageatthe480-VMCCbus which,inturn,willcausemotorfeedercontactorstodropout.

Subsequentenergizationofthe4.16-kVHPCSbusbythediesel generatorresultsinthereenergizationof480-VMCCbus.Auto-closerinterlockswilloperatethecontactorsatapproximately 70percentvoltagetoenergizethemotorloads.Thevoltagesensorsaredesignedtosatisfythefollowingapplicablerequirements:1.Class1EequipmentisutilizedandisphysicallylocatedatandelectricallyconnectedtotheClass1E

switchgear.2.AnindependentschemeisprovidedfortheDivisionIIIClass1EHPCSpowersystem.3.Thesecondlevelofundervoltageprotectionincludescoincidencelogic(2outof2)toprecludespurious tripsoftheoffsitepowersource.4.Thevoltagesensorsautomaticallyinitiatethedisconnectionofoffsitepowersourceswheneverthe voltagesetpointandtimedelaylimitshavebeen

exceeded.5.Capabilityfortestandcalibrationduringpoweroperationisprovided.6.Annunciationisprovidedinthecontrolroombyanybypassesincorporatedinthedesign.TheClass1EHPCSbusloadsheddingschemeautomaticallypreventssheddingduringsequencingoftheemergencyloadstothebus.

Theloadsheddingfeatureisreinstateduponcompletionofthe loadsequencingaction.ThevoltagelevelsattheHPCSbusareoptimizedforthemaximumandminimumloadconditionsthatareexpectedthroughoutthe anticipatedrangeorvoltagevariationsoftheoffsitepower sources.Thetripsettingsselectedarebasedonananalysisof thevoltageattheterminalsoftheClass1Eloads.Theanalyses performedtodetermineminimumoperatingvoltagesconsider maximumunitsteadystateandtransientloadsforeventssuchas unittrip,lossofcoolantaccident,startup,orshutdown,with

the offsite RBSUSARRevision98.3-27November1997powersupply(grid)atminimumanticipatedvoltageandonlytheoffsitesourcebeingconsideredavailable.Maximumvoltagesare analyzedwiththeoffsitepowersupplyatmaximumexpected voltageconcurrentwithminimumunitloads.6Theanalyticaltechniquesandassumptionsusedinthevoltage analysiswereverifiedbyactualmeasurement.Theverification andtestwillbeperformedpriortoinitialfull-powerreactor operationonallsourcesofoffsitepowerby:

61.Loadingthestationdistributionbuses,includingallClass1Ebusesdowntothe120-Vlevel,toatleast30

percent.2.RecordingtheexistinggridandClass1Ebusvoltagesandbusloadingdowntothe120-Vlevelatsteady-state conditionsandduringthestartingofalargeClass1E HPCSpumpmotor.63.Usingtheanalyticaltechniquesandassumptionsofthevoltageanalysisabove,andthemeasuredexistinggrid voltageandbusloadingconditionsrecordedduring conductofthetest,anewsetofvoltagesforthe Class1EHPCSbusdowntothe120-Vlevelwas

calculated.4.Theanalyticallyderivedvoltagevalueswerecomparedagainstthetestresults.

68.3.1.1.3.10ControlInterlocksforACElectricalCircuitsControlcircuitsofall4.16-kVcircuitbreakersand480-Vloadcenterbreakersinsafety-relatedsystemswerereviewedto determineifinadvertentoperationofothercomponentsinthe sameorothersystemsresultedwhenthecircuitbreakerfora particularcomponentwasrackedouttothetestpositionor operatedinthetestposition.Theresultsofthisreviewhave beensummarizedandverifythatthepresentdesignofelectrical controlcircuitryforRBSdoesnotresultinanyinadvertent

operations.91.Inthecaseof4.16-kVcircuitbreakers,interlocktoothercomponentsisachievedusingbreakerauxiliary switchcontacts.Theoperationoftheinterlocked circuitryiscontrolledadministrativelywhenthe circuitbreakerisoperatedinthetestposition.

9 RBSUSAR8.3-28August19872.Inthecaseof480-Vloadcenterbreakers,interlocktoothercomponentsisachievedusingthecontactsofan auxiliaryrelayinthebreakercontrolcircuit.A breakerhousinglimitswitchcontactisusedtolock outthisrelayintherackedoutpositionofthe

breaker.3.13.8kVcircuitbreakersarenotusedtocontrolpowertoanysafety-relatedsystemsorcomponents.4.Inthecaseofmotorcontrolcenters,interlocktoothersystemcomponentsisachievedusingauxiliary relaysintheircontrolcircuits.Testingofmotor controlcentersdoesnotresultinanyinadvertent operationofothersystemcomponents.5.120-Vac/dccircuitbreakersdonotprovideanyinterlockstoothersystemcomponents.8.3.1.1.4SystemProtectionandSurveillance Transformerswiththeirlowvoltagewindingatorabove4.16kV,except1STX-XS3Aand1STX-XS3Batthemakeupwaterarea,have differentialprotection.All4.16-kVand13.8-kVacmotorcircuitshavephasetimeovercurrentrelayswithinstantaneoustripssetabovelocked rotorlevels.Also,4.16-kVand13.8-kVmotorshavetimeover-currentgroundrelaying.Thereactorfeedpumpmotorsandthe reactorrecirculatingpumpmotorswiththeirdedicated transformershavedifferentialprotection.Circuitrelaysare coordinatedwiththoseatthesource.Breakersatthe480-Vlevelhavetime-overcurrenttripping.Allmoldedcasebreakersinmotorcontrolcentersandthededicated motorsupplybreakersin480-Vloadcentershaveinstantaneous shortcircuittrippingdevicessetabovemotorinrushcurrent level.Breakersin480-Vloadcentersservingmotorcontrol centershaveminimumtimedelayonshortcircuits;thoseusedin bus-tieservicehaveintermediatetimedelay;andthoseinmain supplyservicehavemaximumtimedelayonshortcircuits.Load centersinstandbyservicehave480-Vbreakersinthemain supply.Thetrippingselectivityoutlinedandappropriatechoice ofrelaysandthermaltrippingdevicesfacilitateapplicationof therequiredcoordinationofprotection.

RBSUSAR8.3-29August19878.3.1.1.4.1StandbyDieselGeneratorsTheprotectionsystemofstandbydieselgeneratorsisdescribedasfollows(seelogicdiagrams,Figure7.3-23,sheets17through

28):1.Thestandbydieselgeneratorisrenderedincapableofrespondingtoanemergencyautostartsignalduringany dieselgeneratoroperationalcondition(including testingandoperationfromthelocalcontrolpanel)by thefollowingconditions:a.Dieselcontrolpanellossofcontrolpower b.Startingairpressurelow c.Stopsolenoid1EGS*SOV24Aor1EGS*SOV24B,for1EGS*EG1Aor1EGS*EG1B,respectively,energized.

Thedieselgeneratorstopsolenoidisenergized andsealedinwheneverthemanualstoppushbuttons areoperatedorthedieselgeneratorprimaryor backupprotectionrelaysaretripped.Thestop solenoidissealedintopreventanautomatic dieselgeneratoremergencystartoccurringbefore allthedieselgeneratorcontrolsandprotection devicesareresettonormaloperatingconditions.

Thelocalcontrolroomormaincontrolroom operatorcandeenergizethedieselgeneratorstop solenoidbyoperatingtheSTOPRESETpushbutton provided,oneineachcontrolroom.d.Dieselinthemaintenancemode(includesbarringdeviceengaged)e.Overspeedtripdeviceactuated f.Generatorbackupprotectionlockoutrelaytripped g.Generatorprimaryprotectionlockoutrelaytripped2.Thestandbydieselgeneratorunitistrippedunderthefollowingconditionsduringbothnormalandemergency

operation:

a.Engineoverspeed RBS USAR Revision 22 8.3-30 16 b. Both STOP pushbuttons manually operated. For each standby diesel generator unit, two pushbuttons are

located at both the main control room and at the

local control panel. The two pushbuttons are

arranged such that the operator must use both hands

to simultaneously operate both pushbuttons in the main control room. The operator can operate both

pushbuttons with one hand at the local panel.

16 c. Generator differential relay trip

d. Extreme high jacket water temperature and high lube oil temperature trips are active unless a LOCA signal is present or manually bypassed by a local control switch (Applicable to EGS-EG1A and EGS-EG1B ONLY). 3. The standby diesel generator unit is tripped under the following conditions during normal operation only.

a. Generator voltage controlled - inverse time phase overcurrent

b. Generator reverse power

c. Generator loss of field

d. Extreme high jacket water temperature trip

e. High bearing temperature trip

f. Extreme low jacket water pressure trip

g. High crankcase pressure trip

h. Trip low turbo oil pressure

i. Trip high vibration

j. Trip high temperature lube oil

k. Low lube oil pressure trip

l. Generator ground overcurrent

4. Protective functions of each standby diesel generator are annunciated locally in each of the standby diesel

generator control rooms.

The following alarms are separated into subsystem groups. Each subsystem group is provided with a "first

out" indication as per Regulatory Guide 1.9.

RBS USAR Revision 16 8.3-31 March 2003 a. Diesel engine lube oil subsystem (see Figure 7.3-17)(1) Lube oil filter differential pressure high (2) Lube oil strainer differential pressure high (3) Turbo oil pressure low (4) Lube oil pressure low (5) Turbo oil low pressure - TRIP (6) Lube oil low pressure - TRIP (7) Crankcase high pressure - TRIP (8) Lube oil outlet temperature high (9) Lube oil inlet temperature high (10) Lube oil outlet temperature low (11) Lube oil inlet temperature low (12) Lube oil tank level high (13) Lube oil tank level low (14) Lube oil outlet high temperature - TRIP 16(15) Bearing oil high temperature - TRIP 16b. Diesel engine fuel oil subsystem (see Figure 7.3-15)(1) Fuel oil storage tank level low (2) Diesel engine strainer differential pressure high(3) Fuel oil day tank level extreme low (4) Fuel oil day tank level extreme high (5) Fuel oil filter differential pressure high (6) Fuel oil pump overspeed drive failure RBS USAR Revision 16 8.3-32 March 2003 (7) Fuel oil pressure low 1614c. Diesel engine jacket water subsystem (see Figure 7.3-23) 14 16(1) Jacket water pressure low (2) Jacket water extreme low pressure - TRIP (3) Jacket water outlet temperature extreme high - TRIP (4) Jacket water outlet temperature high (5) Jacket water inlet temperature high (6) Jacket water outlet temperature low (7) Jacket water inlet temperature low (8) Jacket water level low d. Diesel engine air start subsystem (see Figure 7.3-16) (1) Start air receiver pressure low (2) Control air pressure low (3) Diesel start air pressure low e. Diesel generator subsystem (see Figure 7.3-23, Sheets 22 and 28) (1) Standby generator differential - TRIP (2) Standby generator fault - TRIP (3) Standby generator ground fault (4) Standby generator loss of field The following standby diesel generator protective functions are annunciated individually: 15 a. DELETED

b. DELETED 15c. Emergency exhaust fan trouble RBS USAR Revision 22 8.3-33 d. Auxiliary systems not in auto 16 e. Bearing high temperature - TRIP 16 f. Fuel oil strainer differential pressure high

g. Fuel oil dc pump running

h. After cooler water inlet temperature high

i. Barring device engaged

j. Diesel start air pressure high

k. Unit start failure

l. Vibration - TRIP

m. Overspeed - TRIP

n. 4160 Standby bus distribution breakers auto -TRIP

o. Diesel generator potential circuit blown fuse

p. 4160 Standby bus undervoltage

In addition to the above-listed annunciators, the

following standby diesel generator conditions are also

indicated in each diesel generator control room: 14 a. Unit available emergency status - white light on

b. AC control power - white light on

c. DC control power - white light on

d. Ready to load - white light on

e. Unit tripped - amber light on 14 f. At synchronous speed - red light on

g. Starting - red light on

h. Shutdown system active - red light on

i. High t emperature bypass switch, o perate - white light on, Bypass - amber light on (Applicable to EGS-EG1A and EGS-EG1B ONLY).

5. The following remote annunciation is provided in the main control room for each standby diesel RBS USAR Revision 16 8.3-34 March 2003 8 generator (1EGS*EG1A and 1EGS*EG1B). Window engraving for the cited condition is exact wording. The events

which cause the window to annunciate are also listed.

8a. "STANDBY DIESEL GENERATOR 1EGS*EG1A INOPERATIVE" 16 Actuated by the following conditions. These conditions are also provided with individual amber lights in the main control room (except for items 8 and 10 which have system level input only). The following describes the wording

engraved on the associated amber light window and

the failed or inoperative condition.

16(1) "LOSS OF CONT. PWR. FWD/REAR ST. CKT." -Both forward and rear air start 125-V dc control

power failed.(2) "LOSS OF FORWARD AND REAR ST. AIR" - Both forward and rear starting air failure.(3) "MAINT. MODE L.O. SOL. ENERGIZED" - Local control room maintenance mode selector switch

and main control room diesel engine mode

selector switch in the MAINTENANCE position.(4) "DSL. ENG. OVERSPEED TRIP" - Diesel engine overspeed device actuated.(5) "STBY GEN. DIFF./FAULT TRIP" - Diesel generator primary or backup protection

lockout relays tripped.(6) "DSL ENG. STOP SOLENOID ENERGIZED" -Manual stop pushbuttons operated, or diesel

generator primary, or backup protection

relays tripped. 1 1 RBS USAR 8.3-35 August 1988 1(7) "GEN/EXC. LOSS OF DC CONT. POWER" - Loss of the diesel generator exciter and regulator

125-V dc control circuit. (8) "LOSS OF EXCITER FIELD DC PWR." - Loss of 125-V dc power to the diesel generator field

winding.(9) "DIESEL GEN. MANUALLY BYPASSED" -Manually-operated switch, operated whenever any diesel

generator system controls or protection

devices are deliberately bypassed. (10) "AUX. CKT. LOSS OF CONTROL POWER" - Loss of 125-V dc to the diesel generator inoperative

annunciator control circuit.

1b. "DIESEL GEN. 1A PT BLOWN FUSE" - Actuated when the diesel generator breaker is closed, and the backup

protection lockout relay is reset, and any one of

the diesel generator potential transformer primary

fuses are blown.c. "4160-V STANDBY BUS DISTR. BREAKER INOPERATIVE" -

This annunciator window is a common alarm point actuated by any one of the following conditions.

These conditions also actuate a common inoperative amber light titled, "4.16 STBY. BUS DISTR. BREAKER

INOPERATIVE." The conditions are: (1) Loss of 125-V dc control power.

(2) Loss of breaker control circuit blown fuse.

(3) Breaker not in operate position.

(4) Breaker lockout relay tripped.

The 4160-V standby bus distribution breakers associated with this common alarm point are: (1) 4.16-kV Bus 1A Normal Supply RBS USAR Revision 16 8.3-36 March 2003 (2) 4.16-kV Bus 1A Alternate Supply (3) 4.16-kV Bus 1A Generator Supply (4) 4.16-kV Bus 1A Generator Neutral Breaker (5) 480 V LDC 1A Supply (6) 480 V LDC 2A Supply d. "4160-V STANDBY BUS DISTR. BREAKER AUTO TRIP" - This annunciator window is a common

alarm actuated when the local or remote

breaker control switch is in the AFTER START

position and the breaker is automatically

tripped open.This condition also actuates the amber light associated with each breaker control switch.

The 4160-V standby bus distribution breakers are listed in Section 8.3.1.1.4.1, Item 5c

above.1615e. "STBY DIESEL GEN. TROUBLE" - This annunciator window is a common alarm actuated by the conditions listed in Section 8.3.1.1.4.1, Items 4.a.1 through 4.a.14, Item 4.b.2, Items 4.b.5 through 4.b.7, Items 4.c.1 through 4.c.8, Items 4.d.1 through

4.d.3, Items 4.e.1 through 4.e.4, plus items e

through m of the protective functions listed as

annunciated individually.

15 161f. "DIESEL FUEL OIL STORAGE TANK LEVEL LOW" 1g. "DIESEL FUEL OIL DAY TANK EXTREME LOW LEVEL" -This annunciator window is actuated from a switch receiving an input signal from the fuel oil day

tank level transmitter.h. "4 kV STBY BUS NORMAL & ALT SUPPLY BKRS CLOSED" -

This annunciator is actuated when 15 sec after both normal and alternative supply breakers close on 4-

kV standby bus.i. "4 kV STBY BUS DISTR BKR AUTO TRIP" - This annunciator is actuated when diesel generator

breaker trips automatically.

RBS USAR Revision 22 8.3-37 j. "4 kV STBY DSL GEN. NEUTRAL BKR AUT TRIP" -This annunciator is actuated when diesel generator

neutral breaker trips automatically.

k. "DSL. GEN BACKUP PROT. ACTIVATED" - This annunciator is actuated on reverse power, ground

overcurrent, controlled-inverse time phase

overcurrent, and loss-of-field faults (when diesel

generator breaker is closed).

l. "DSL GEN PROT CKT LOSS OF CONT. PWR" - This annunciator is actuated when control power of

diesel generator protection circuit is lost.

m. "STBY DIESEL GEN HIGH TEMP TRIPS MAN BYPASSED" is actuated when the local bypass switch is in the "BYPASS" position (Applicable to EGS-EG1A and EGS-EG1B ONLY).

6. Each standby diesel generator set is capable of being emergency started in the operational mode from the main control room as well as the standby diesel generator control room near the engines. There is no transfer

scheme between these two locations, since the emergency start controls are in parallel. Normal start controls

are on the local engine control panel only in the

standby diesel generator control room near the engines (Fig. 8.3-11).

7. All standby diesel generator parameters that are bypassed under accident conditions are annunciated in each standby diesel generator control room. These

annunciators are located on the associated standby

diesel engine control panel.

8. All conditions that render the standby diesel generator incapable of responding to an automatic start signal

are annunciated in the main control room.

8.3.1.1.4.1.1 Qualification Testing

In accordance with Branch Technical Position EICSB-2, Diesel

Generator Reliability Qualification Testing, the standby diesel

generator manufacturer, Delaval Engine and Compressor Division, has performed a series of qualification tests to verify

compliance with the requirements of the above-referenced NRC BTP.

Surveillance instrumentation is provided to monitor the status of the power supply and starting equipment of each standby generator. Instrumentation and control are essential

requirements in the design, installation, testing, operation, and maintenance of the standby generator. All RBSUSAR8.3-38August1987conditionswhichcanaffectperformanceorindicateunavailabilityofeachstandbygeneratorareannunciatedinthe maincontrolroom.Localindicatorsandcontrolsofeachdiesel generatorarelocatedwithintheirrespectiverooms.Remote indicatorsandcontrolsarelocatedinthemaincontrolroomon separatesectionsofthecontrolboard.Additionalinformationon instrumentationandcontrolsispresentedinSection7.3.1.The controlsandinstrumentcablesareroutedtopreventcommon failure.Allcontrolswitchesonthemaincontrolboardare clearlyidentifiedastotheequipmentthateachswitchcontrols (Section7.1.2.3).FactorytestingofthestandbyacpowersystemswasperformedasdefinedinIEEE-387,CriteriaforDiesel-GeneratorUnitsApplied asStandbyPowerSuppliesforNuclearPowerGeneratingStations.Standbydieselgenerator1EGS*EG1Awasgiven37startqualificationtestsinaccordancewithIEEE387andIEEE323at theTDIfactory.Eachstartverificationtestwasperformedfrom astandbytemperatureof150°F-10°Fandincludedpickupof 1,750kWwithin10secofthestartsignal(therewerenostart failures).VariousadditionalTDIfactoryqualificationtests wereperformedforbothstandbydieselgeneratorsasdiscussedin Item2ofReference3.Inaddition,qualificationtestswere performedatRiverBendStationinaccordancewithRegulatory Guide1.9,ParagraphsC.13andC.14,andRegulatoryGuide1.108, asdiscussedinSection8.3.1.1.5.2.8.3.1.1.4.2HighPressureCoreSprayPowerSupplySystem TheprotectionsystemoftheHPCSdieselgeneratorisdescribedasfollows:1.ThefollowingconditionsrendertheHPCSdieselgeneratorincapableofrespondingtoanautomatic emergencystartsignal:a.Dieselgeneratorlockoutrelaysnotreset.

b.Dieselenginemodeswitchnotin"AUTO"position(modeswitchin"MAINTENANCE"or"TEST"position).c.Dieselgeneratoroutputbreakerclosedbeforestartofdiesel.

RBSUSAR8.3-39August1987d.Dieselgeneratoroutputbreakerinracked-out position.e.Dieselgeneratorregulatormodeswitchnotin"AUTO"position.f.Insufficientstartingairpressure.

g.Lossofdcpowertodieselgeneratorcontrolsorthe4,160Vswitchgear.h.Dieselenginetrip/lockoutrelaynotreset.

i.Lowfueloillevelindaytank.

Itemseandidonotelectricallyblockdieselgeneratorfromemergencystarting;however,these conditionsarechecked,andcorrectedifnecessary, priortoallowingdieselgeneratortorespondtoan automaticemergencystartsignal.2.Thefollowingalarmsareprovidedatthemaincontrolroomannunciatorforabove-listedconditions.a.Itemsa,b(modeswitchin"TEST"),d,e,f,andgareannunciatedas"HPCSSYSTEMNOTREADYFORAUTO

START".b.Itemcisindicatedbymeansofbreakerstatuslight(RED).c.Itemb(modeswitchin"MAINTENANCE")isannunciatedas"DIESELENGINEINMAINTENANCE."d.Itemhisannunciatedas"DIESELENGINETRIP" alarm.e.Itemiisannunciatedas"DIESELENGINETROUBLE"alarm(commonalarm).3.ThefollowingHPCSdieselgeneratoremergencyconditionsareannunciatedlocallyonthediesel generatorcontrolpanelandasacommon"DIESELENGINE TROUBLE"alarminthecontrolroom:a.Enginefailuretostart/run b.Engineoverspeed RBSUSAR8.3-40August1987c.Lowfuelleveld.Crankcasepressurehigh e.Highlubeoiltemperature f.Highwatertemperature g.Chargerfailure h.Enginetripped i.Mainfuelpumpfailure j.Lowlubeoiltemperature k.Lowexpansiontankwaterlevel l.Highstatortemperature m.Reservefuelpumpfailure n.Lowlubeoilpressure o.Lowcoolingwaterpressure p.Lowturbochargerlubeoilpressure q.Restrictedfueloilfilter r.Restrictedlubeoilfilter s.Lowstartingairpressure t.Controlpowerfailure u.DCturbolubeoilpumprunning v.DCcirculatinglubeoilpumprunning.4.Thefollowingadditionalalarmsalsoareprovidedinthecontrolroom:a.HPCS4-kVbusautotrip b.HPCSsystemundervoltage c.HPCSpumpmotorovercurrent d.Dieselenginerunning RBSUSAR8.3-41August1987e.125-Vdcsystemtroublef.HPCSbatterychargertrouble g.Generatortrip/lockout h.Dieselenginegeneratorovercurrent i.HPCSsystemground j.HPCS480-Vsystemundervoltage k.DivisionIIIdegradedvoltage l.Dieselengineoverspeed m.HPCScontrolpowerfailureorbreakerinlower positionn.Remoteshutdowntransferswitchinemergency position.WhentheHPCSdieselgeneratoriscalledupontooperateunderaccidentconditions,theonlyprotectivedevicesusedarethe generatordifferentialrelaysandengineoverspeedtripdevice.

Theengineoverspeedtripdeviceismechanicalandtripsthe enginedirectly.Thetripsareannunciatedinthemaincontrol room.Otherprotectiverelays,suchaslossofexcitation,anti-motoring(reversepower),overcurrentwithvoltagerestraint, highjacketwatertemperature,andlowlubeoilpressure,are usedtoprotectthemachinewhenitisoperatingduringperiodic tests.Theserelaysareautomaticallyremovedfromthetripping circuitsunderaccidentconditions.Inadditiontothese protectiverelays,anormaltimedelayovercurrentrelaysenses generatoroverloadandcausesanalarminthemaincontrolroom.

Thegeneratordifferentialrelaysandoverspeedtripdeviceare retainedunderaccidentconditionstoprotectagainstwhatcanbe majorfaultswhichcouldcausesignificantdamage.Allthe bypassedprotectivedevicescausealarmsinthemaincontrolroom andtheoperatorthenhassufficientinformationtotake necessarycorrectiveaction.Becauseduringaccidentconditions theHPCSdieselgeneratorisperformingasafety-related function,theseprotectivedevicesareinsignificantsofaras theengineconditionisconcerned.Theengineiscapableof operatingundertheseabnormalconditions,anditislefttothe operator'sjudgmentwhethertooperatetheengineortripit

manually.

RBS USAR Revision 16 8.3-42 March 2003 8.3.1.1.4.2.1 Qualification Testing A prototype test has been performed to establish the adequacy of the diesel generator unit to successfully accelerate the HPCS pump and system loads. The test consists of starting an HPCS

system in an actual HPCS pump loop test (HPCS system in

condensate to condensate test mode) with auxiliary loads several times within the design time requirement. A topical report on

HPCS power system unit, NEDO-10905, and subsequent amendments describe and show theoretical and experimental evidence as to the adequacy of the design. The topical report has been further

amended to include the results of the prototype qualification

test cited above. 16 In order to comply with the requirements, the tests described in NEDO-10905, Section 6.6 have been performed.

16Start and Load Reliability Test 1. Prior to initial fuel loading of the reactor unit, a series of tests will be conducted to establish the

capability of the HPCS diesel generator unit to

consistently start and load within the required time. 2. With the exception of those diesel engine/generator designs that are identical (minor changes may be

justified by analysis) to the diesel generator unit(s)

which have been previously qualified for the HPCS

application, all other different diesel engine/generator combinations will be individually

qualified for reliable start and load acceptance

requirements.3. An acceptable start and load reliability test is defined as follows: A total of 69/n (where n is the number of diesels, 1) valid start and loading tests

with no failure or 128/n valid start and loading tests with a single failure will be performed. Failure of

the unit to successfully complete this series of tests

as prescribed will require a review of the system

design adequacy, the cause of the failure to be corrected, and the tests continued until 128 valid tests are achieved without exceeding the one failure.

The start and load tests will be conducted for 69 cold

fast starts.

RBSUSAR8.3-43August1987Thefaststartsareconductedwiththeengineinareadystandbystatusandincludealoadingtoatleast 50percentofthecontinuousloadandoperationatthis loadforatleast1hr.Duringand/orfollowingthis testing,someindividualcomponentsofthediesel generatororitssupportsystemsmayrequire maintenanceand/orreplacement.Thismaintenanceand/or replacementduetoweardoesnotrequireretesting.Ifthecauseforfailuretostartoracceptloadinaccordancewiththeprecedingsequencefallsunderany ofthefollowingcategories,thatparticulartestmay bedisregarded,andthetestsequenceresumedwithout penaltyfollowingidentificationofthecauseforthe unsuccessfulattempt:a.Unsuccessfulstartattemptswhichcandefinitelybeattributedtooperatorerrorincludingsetting ofalignmentcontrolswitches,rheostats, potentiometers,orotheradjustmentsthatmayhave beenchangedinadvertentlypriortothat particularstarttest.b.Astartingand/orloadingtestperformedduringroutinemaintenanceortrouble-shooting.All maintenanceproceduresaredefinedpriorto conductingthestartandloadacceptance qualificationtestsandbecomeapartofthe normalmaintenancescheduleafterinstallation.c.Failureofanyofthetemporaryservicesystemssuchasdcpowersource,outputcircuitbreaker, load,interconnectingpiping,andanyother temporarysetupwhichwillnotbepartofthe permanentinstallation.d.FailuretocarryloadwhichcanbedefinitelyattributedtoloadingsinexcessoftheHPCS dieselgeneratorrating.e.Unsuccessfulstartattemptswhichwereconductedwiththeintentofeventualfailure,e.g.,the lastattemptwhendeterminingcapacityoftheair startsystem.

RBSUSAR8.3-44August19878.3.1.1.4.3ContainmentElectricalPenetrationProtectionElectriccircuitspenetratingtheprimarycontainmentthroughClass1Eelectricalpenetrationsareclassifiedasfollows:1.Mediumvoltagepower4.16-kV,three-phase 2.Lowvoltagepower:a.480-Vthree-phasefeedersfromloadcentersb.480-Vthree-phasefeedersfrommotorcontrol centersc.120/240-Vsingle-phasefeedersfromlightinganddistributiontransformers.3.Lowvoltagecontrolandsignalpower:a.120-Vsingle-phase b.125-Vdc4.InstrumentationcircuitsContainmentelectricalpenetrationassembliesaredesignedtowithstand,withoutlossofmechanicalintegrity,themaximum faultcurrentversustimeconditionwhichcouldoccurbecauseof singlerandomfailureofcircuitoverloadprotectivedevices.No singlefailurecausesexcessivecurrentinpenetrationconductors whichdegradepenetrationseals.Allprotectivedevices automaticallydisconnectpowertothepenetrationconductorswhen currentsthroughtheconductorsexceedtheestablishedprotection limits.Mediumvoltagepower(4.16kV)penetrationsareprotected againstoverloadbytworedundantbreakers.Thesebreakersare qualifiedfortheirserviceenvironmentandreceivetripping signalsfromtwoindependentchannels,physicallyseparatedand poweredbyseparatesources.Shortcircuitprotectionis providedforlow-voltagepowerpenetrationsbytwodevices-a primaryprotectivedeviceandabackupprotectivedevice-with theelectricalpenetrationratedforthemostseveredutyofthe twodevices.Bothprotectivedevicesarequalifiedfortheir serviceenvironment.Whentheelectricalpenetrationisratedto carrytheavailableshortcircuitcontinuously,nobackup protectiondeviceisrequired,e.g.,inaninstrumentcircuit whichinherentlyhashighimpedanceandissubjectedtolowshort circuitcurrents.

RBSUSARRevision108.3-45April1998Electricalpenetrationscontainingpowercircuitslistedin2aand2babovearenominallyratedtocarry180percentoffull loadcurrentcontinuouslywithallothercircuitsinthesame penetrationoperatingatfullload.Overloadprotectionofelectricalpenetration480-Vmotorcontrolcenterpowercircuitsisprovidedbyaseries-connectedmolded casecircuitbreakerandfuse,eachratedtoopenthecircuit duringoverloadconditions,thusprovidingredundantprotection.

Penetrationprotectionfor120-Vaclightinganddistribution panelsareprovidedbyseries-connectedmoldedcasecircuit breakerslocatedbetweenthelightingordistributiontransformer secondaryandtheelectricalpenetration.Noredundant protectionisprovidedforneutronmonitorSRMandIRMmotor moduleloadsfedfrom1NHS-MCC2Csincethepenetrationassembly isdesignedtocarrythemaximumavailablefaultcurrent

continuously.10480-Vloadcenterloadcircuitsareprotectedbyredundant protectiondevicesasinthecaseofthepolarcrane.Redundant protectionconsistsofeitherthefeederbreakerbackedupbythe secondarymainbreaker(viatimeovercurrentrelaylogic tripping)forthecontainmentunitcoolercircuits,or,ofa powersupplyfusebackedupbythefeederbreaker,asforthe hydrogenrecombinercircuits.

10Low-voltagecontrolcircuitsevaluatedfallintooneofthe followingcategories:1.Thecircuitisself-protectingduetothelimitedavailableshort-circuitcurrentatthepenetration beinglessthanthecontinuousratingofthe

penetration.2.Backupprotectionisprovided.

3.Thecircuithasbeenanalyzedandithasbeendeterminedthatbackupprotectionisnotwarranted (i.e.,CTleadsondifferentialcircuit,tripcoil

circuits).

• 104.Administrativelydeenergizingthecircuitryduringplantoperation(i.e.,ERFsystem,spaceheatersfor motors,andLScompartments).

10 RBSUSAR8.3-46August19878.3.1.1.5MaintenanceandTesting8.3.1.1.5.1AuxiliaryElectricalPowerSupplySystems Maintenanceandtestingofauxiliaryelectricalpowersystemequipmentareconductedtoensurethatallcomponentsare operationalwithintheirdesignlimits.Maintenanceandtesting areperformedperiodicallythroughoutstationlifeinaccordance withnormalstationoperatingproceduresto:1.Detectthedeteriorationofthecomponentsofthesystemtowardanunacceptableconditionandtotake correctiveactionasrequiredtobringthecomponents toanacceptablecondition.2.Demonstratethecapabilityofthecomponentswhichwillnormallybedeenergizedtoperformproperlywhen

energized.Theinherentredundancyofthestandbyelectricalsystemspermitssupportoffullfunctionaltestingofsystemsorsubsystems.

Componentsofthestandbysystemscanbemadeinoperablefor shorttimetestpurposeswithoutimpairingtheultimate capabilityofthesystemsandthesubsystemswhichtheysupport.

Informationconcerningtheabilityofthepowersystemsimportant tosafetytomeettherequirementsofGDC18isgivenin Section3.1.2.18.Thecapabilityfortestingandcalibratingallactuationdevices,circuits,electricalprotectiverelays,andrelated instrumentationduringnormaloperationisdesignedintothe powersystemsimportanttosafetyandinaccordancewiththe recommendationsofRegulatoryGuide1.22.Provisionstoperform nondestructivetestsundersimulatedfaultconditionsare provided.Thisincludesbutisnotlimitedtotheabilityofthe protectionsystemtoinitiatetheoperationoftheactuated

equipment.8.3.1.1.5.2StandbyElectricalPowerSupplySystemsMaintenanceandtestingofthestandbydieselgeneratorsareconductedtoensurethatallcomponentsandauxiliariesare operationalwithintheirdesignlimits.Inadditiontothequalificationtestsconductedoneachdieselgeneratorsetattheenginemanufacturer'sfactory,thestandby dieselgeneratorsaresubjectedto69/n(wherenisthenumberof diesels,2)startandloadtestswithnosinglefailureor128/n startandloadtestswithasinglefailure.Failureofadiesel tocompletethisseriesof RBSUSARRevision88.3-47August1996testswillrequireareviewofsystemdesignadequacy,thecauseoffailuretobecorrected,andthetestscontinueduntil128/n validtestsareachievedwithoutexceedingtheonefailure criterion.Thestartandloadtestsareconductedwiththe engineinthereadystandbystatusandincludealoadingtoat least50percentofthecontinuousloadandoperationatthis loadforatleast1hr.Eachdieselgeneratorsetwasgivenaloadcapabilitytestattheirratedloadof3,500kWfor24hr.However,thestandby dieselgeneratorswillnotbeloadedabovetheloadsindicatedin Tables8.3-2aand8.3-2b.Therefore,the24-hr,3,500-kWload capabilitytestmorethansatisfiesthe110percentoverload requirementofparagraphC.2.a(3)ofRegulatoryGuide1.108when appliedtothequalifiedload.ThefollowingtestswereperformedinaccordancewithIEEE-387aftercompleteinstallationofthestandbydieselgenerator systematRiverBendStation.a.Startingtest b.Loadacceptancetest c.Ratedloadtests d.Designloadtests e.Loadrejectiontests f.Electricaltests g.Subsystemtests8Periodictestsareperformedtoverifythatsystemsand componentsofthestandbydieselgeneratorsperform satisfactorilyandtoensurethatthestandbydieselgenerator systemsmeettheiravailabilityrequirements.Thesetestsare performedduringnuclearplantoperationaccordingtoRegulatoryGuide1.108andaredescribedintheTechnicalSpecifications/

Requirements.

8Testingproceduresindicatethatno-loadandlight-loadconditionsaretobeavoidedandtestingshouldbeaccomplished withaminimumloadingof25percentofratedload.Some exceptionstothisareallowedsuchastimestartcheckswhen otherequipmentisfoundinoperable.Thenormalmaintenanceand surveillancescheduleprovidessufficientloadedrunningtimeto minimizedetrimentaleffectsoftheseexceptions.

RBSUSARRevision88.3-48August1996Emergencydieselgeneratorequipmentfailuresarerepairedpromptly,andanevaluationastothecauseofthefailureis performedanddocumentedinequipmenthistory.Administrative proceduresprovideapprovedmethodsfordesignchangesor replacementofequipmentwithhighfailurerates.Aftermajormaintenanceorextendedoutageofthediesel,acompletesystemlineupperthesystemoperatingprocedureis performedpriortoastartattempt.Thisincludesvalve, electrical,instrument,andcontrolboardlineupsaswellasa visualinspectionofthedieselgeneratoranditsauxiliaries.

Inaddition,compliancewiththeprotectivetaggingandtemporary alterationsproceduresalongwithsystemrestorationsectionsof maintenanceandsurveillanceproceduresensuresystemreadiness.Uponcompletionofanymanual,test,orautostartofthediesel,theoperatorisdirectedbythesurveillanceorsystemoperating proceduretoplacethedieselinanautomaticstandbyreadiness

condition.CompliancewithTechnicalSpecifications,administrativeandsystemoperatingprocedures,andthepreventivemaintenanceand surveillancetestingscheduleensuresoptimumequipmentreadiness andavailabilityupondemand.8.3.1.1.5.3HighPressureCoreSprayPowerSupplySystem8ReadinessoftheHPCSdieselgeneratorisdemonstratedby periodictestingaccordingtoRegulatoryGuide1.108andis describedintheTechnicalSpecifications/Requirements.The testingprogramisdesignedtotesttheabilitytostartand accepttheHPCSdieselgeneratordesignloadsconnectedtobus 1E22*S004.TheHPCSdieselgeneratorisrunfor24hratits continuousratingof2,600kW,2hrofwhichitissubjectedtoa 110-percentoverloadtest(seeTable8.3-3).Thisensuresthat coolingandlubricationareadequateforextendedperiodsof operation.Fullfunctionaltestsoftheautomaticcontrol circuitryareconductedonaperiodicbasistodemonstrate correctoperation(Section7.3.2).

8Meansareprovidedforperiodicallytestingthechainofsystemelementsfromsensingdevicesthroughdrivenequipmenttoassure thattheHPCSpowersupplyisfunctioninginaccordancewith designrequirements.Thedrawoutfeatureofprotectiverelays allowsreplacementrelaystobeinstalledwhiletherelaythatis removedisbenchtestedandcalibrated.

RBS USAR Revision 23 8.3-49 Startup of onsite power units can be initiated by simulation of LOCA signal or loss of power to the plant auxiliary power system.

Connection of the HPCS diesel generator to the HPCS bus takes

place automatically on loss of plant auxiliary power to the HPCS bus (HPCS bus low voltage). The HPCS diesel generator bus

directional overcurrent, ground overcurrent, and phase overcurrent protective relaying provides a trip to the offsite power feeder breaker in case of loss of offsite power while the

diesel generator is in the test mode operation.

8.3.1.1.5.4 Uninterruptible Power Supply Systems 13 Maintenance and testing are conducted to ensure that all components of the 120-V ac uninterruptible power supply systems are operational within their design ratings, and the testing can be performed without disconnecting the loads from their power sources by use of the manual bypass switch. Maintenance and testing of equipment and systems are conducted periodically to detect deterioration of equipment toward an unacceptable

condition and to take corrective action as required to bring the components to an acceptable condition. Preoperational and periodic testing complies with IEEE-308, Criteria for Class 1E

Electrical Systems for Nuclear Power Generating Stations.

8.3.1.1.5.5 Testability of Offsite/Onsite Power Systems 6 Testing the transfer from onsite power, of the main generator 1GMS-G1, through normal station service transformers, to offsite power, via the preferred station service transformers, can be performed when the reactor power is at a low load condition. The transfer from onsite power to offsite power is performed with

buses loaded and is limited to 13.8-kV buses 1NPS-SWG1A and 1NPS-

SWG1B as well as 4.16-kV buses 1NNS-SWG1A and 1NNS-SWG1B. Since 1NNS-SWG1C and E22-S004 are powered from either 1NNS-SWG1A or 1NNS-SWG1B, they will also transfer from onsite to offsite power as a result of the transfer of the bus it is aligned to (1NNS-SWG1A or 1NNS-SWG1B). Standby 4.16-kV buses 1ENS*SWG1A and 1ENS*SWG1B are always connected to preferred offsite power circuits and are therefore not affected in the transfer test.

Normal 13.8-kV buses 1NPS-SWG1C and 1NPS-SWG1D are always connected to preferred offsite power circuits and therefore not

affected in the transfer test.

13 7 4 Offsite power can be connected to 13.8-kV bus 1NPS-SWG1A via preferred transformer 1RTX-XSR1E and circuit breaker 1NPS-ACB11, and to 13.8-kV bus 1NPS-SWG1B via preferred transformer 1RTX-

XSR1F and circuit breaker 1NPS-ACB27.

4 6 7 RBS USAR Revision 23 8.3-49a 7 4 Onsite power can be connected to 13.8-kV bus 1NPS-SWG1A via normal transformer 1STX-XNS1A and circuit breaker 1NPS-ACB09, and to 13.8-kV bus 1NPS-SWG1B via normal transformer 1STX-XNS1B and circuit breaker 1NPS-ACB25.

Offsite power can be connected to 4.16-kV bus 1NNS-SWG1A via preferred transformer 1RTX-XSR1C and circuit breaker 1NNS-ACB07, and to 4.16-kV bus 1NNS-SWG1B via preferred transformer 1RTX-XSR1D and circuit breaker 1NNS-ACB15. Onsite power can be connected to 4.16-kV buses 1NNS-SWG1A and 1NNS-SWG1B via normal transformer 1STX-XNS1C and circuit breakers 1NNS-ACB06 and 1NNS-ACB14, respectively.

The logic that 4 7 RBSUSARRevision68.3-49bAugust1993THISPAGELEFTINTENTIONALLYBLANK RBS USAR Revision 23 8.3-50 automatically transfers a 13.8-kV or 4.16-kV bus from onsite to offsite power is the loss of voltage on the respective 13.8-kV or 4.16-kV bus. The test is performed by manually tripping the 13.8-kV or 4.16-kV breaker from the normal transformer. The voltage loss causes the 13.8-kV or 4.16-kV breaker from the preferred transformer to close onto the respective 13.8-kV or 4.16-kV bus. During the fast transfer, the outage is of such short duration that the motors remain running and the power system remains

intact. 6 Offsite power is connected to 13.8-kV bus 1NPS-SWG1C via preferred transformer 1RTX-XSR1E and normally closed circuit breaker 1NPS-ACB43 and to 13.8-kV bus 1NPS-SWG1D via preferred transformer 1RTX-XSR1F and normally closed circuit breaker 1NPS-ACB44. 13.8-kV switchgear 1NPS-SWG1C and 1NPS-SWG1D do not have

a back up source of power or transfer to another source.

6 13 7 7 Standby 4.16-kV bus 1ENS*SWG1A is connected to preferred transformer 1RTX-XSR1C via normally closed circuit breaker 1ENS*ACB06, to normal 4.16-kV bus 1NNS-SWG1B via normally open circuit breakers, and to standby diesel generator 1EGS*EG1A via

normally open circuit breaker 1ENS*ACB07. Standby 4.16-kV bus 1ENS*SWG1B is connected to preferred transformer 1RTX-XSR1D via normally closed circuit breaker 1ENS*ACB26, to normal 4.16-kV bus 1NNS-SWG1A via normally open circuit breakers, and to standby diesel generator 1EGS*EG1B via normally open circuit breaker 1ENS*ACB27. The transfer test is performed for each bus as

follows: 13 RBSUSARRevision138.3-50aSeptember2000THISPAGELEFTINTENTIONALLYBLANK RBSUSARRevision68.3-50bTHISPAGELEFTBLANKINTENTIONALLY RBS USAR Revision 20 8.3-51 813 The loading of a standby diesel generator is performed manually during testing while the reactor is in normal operation. The standby diesel generator is manually synchronized onto the standby bus and then carries selected standby loads. A synchronous check relay is provided to

prevent breaker closure during synchronizing operations unless the busses are synchronized within the tolerances of the relay. By opening the breaker from the preferred stat

ion service transformer and closing the breaker connecting

the standby 4.16-kV bus to the normal 4.16-kV bus, the

standby diesel generator load can be simulated to its

approximate qualified load. Selected motors are running on

the standby bus during the test.

8 138.3.1.1.5.6 Procedural Control of Jumpers and Other Temporary Forms of Bypassing Use of jumpers or other temporary forms of bypassing is controlled through implementation of the following procedures: 1. Surveillance Test Procedures - These are written so that in the body of the procedure specific steps direct

altering the system to accomplish testing; once testing is complete, specific steps also direct returning the system to the original condition. To ensure this is done properly, a second signoff by a qualified

individual is required to verify normal conditions.

2.The Temporary Modifications (Alterations)p rocedure establish es the requirements and methods for controlling activities that temporarily altered the design function of a system or component. The

requirements of this procedure applied to all activities that temporarily altered the design function

of any component or system after the

Preoperational/Acceptance Test Phase and the system or

component had been turned over to the plant operating

staff.8 The changes covered were as follows: a change that inhibited or altered the intended operation of a plant component or system such as electrical jumpers, lifted

wires, open links, piping blocks and bypasses, papered

contacts, or temporary set points that were intended to

be returned to normal or permanently incorporated at

some later date and not otherwise covered by an

approved procedure which returned the system back to

normal.8 RBS USAR Revision 24 8.3-52 8 8 3. The maintenance work process uses several procedures that establish administrative controls for identifying, controlling, and documenting maintenance and

maintenance-related activities. These procedures

provides step-by-step instructions to ensure that troubleshooting and/or maintenance is accomplished properly. It also provides for testing by use of

approved surveillance test procedures to ensure the system or component has been properly repaired and

returned to service. 14 7 The S hift Manager has complete control of all activities that might alter or prevent a system from

performing as it is designed.

7 14 8.3.1.1.6 Safety-Related Systems Design Criteria

8.3.1.1.6.1 Electric Motors and Torque Considerations

Motors employed for Class 1E service are designed and constructed

to IEEE-323, -334, and -344 as well as all applicable industry standards in effect at the time of their purchase (Sections 3.9

and 3.11).

Motors are matched to the driven equipment so as to produce sufficient accelerating torque to successfully start the

equipment at minimum available motor terminal voltage. A start

is considered successful if rated speed can be obtained in less than 5 sec, and within the allowed motor heating curve. This has been generally achieved by requiring a minimum of 10 percent difference between the instantaneous available driver torque and

driven equipment demand torque.

8.3.1.1.6.2 Temperature Monitoring and Circuit Protection

The nature of Class 1E electrical equipment is such that protection of the equipment is secondary to accident mitigation and safe shutdown of the plant. Temperature monitors and overload heaters are set only to alarm on

overload/overtemperature conditions during LOCA operation of Class 1E MOVs. Trip circuits actuate only to prevent

catastrophic failure which could augment rather than mitigate an undesirable circumstance. Coordination calculations show that protective devices actuate at the lowest level necessary to isolate a fault. All protective devices are set for a minimum of 125 percent of the full load current rating of the equipment at

all Class 1E voltage RBSUSAR8.3-53August1987levels.Nocascadingofprotectivedeviceshasbeenemployed.SeealsoSection8.3.1.1.4.2regardingHPCScircuitprotection.TheRiverBendStationdesignhasbeenreviewedtoidentifyanylargehorsepower(rated100hpormore)safety-relatedmotor/pump combinationsthathavepressureswitchesorotherpermissive devicesincorporatedintothefinalactuationcontrolcircuitry.

Thesemotorsandpermissivedevices,alongwiththeredundancy anddiversityprovidedforsuchdevices,arediscussedinthe followingparagraphs.1.High-PressureCoreSpraySystem(E22)RedundantundervoltagedevicesmonitorbusvoltagesothatfailureofonedevicetodetectavailableHPCSpoweronthe busdoesnotpreventthemotorfromstarting.However,ifa lossofbusvoltageissensedbymorethanonechannelof undervoltagerelays,theHPCSpumpisinhibitedfrom

starting.CertainprotectivetripscaninhibitaHPCSDGstartundertestconditions;however,allbuttwooftheDGtripsare bypassedinthepresenceofanemergencystartsignal.The twoexceptionsaretheoverspeedtripandthegenerator differentialdevicetripwhichprotectsthedieselgenerator.

Thesedevicesarecapableofbeingtestedduringnormal

operations.AlthoughredundancyofcertaincomponentsisappliedwithinHPCSinordertoimprovereliability,theoverspeedand differentialtripsarenotredundantbycomponent.TheECCS networkisredundantbysystem.2.ResidualHeatRemovalSystem(E12)TherearenopressureswitchescapableofinhibitingamanualorautomaticstartoftheRHRsystem.TheRHRpumpmotor switchgearreceivesastopsignalifeitherthe1E12*MOVF004B or1E12*VF066Bvalveisfullopenandthevalve 1E12*MOVF006B,1E12*MOVF009,or1E12*MOVF008isnotfully open.Limitswitcheswhichsensethefullopenvalve positionandgenerateappropriatefullopenpermissiveare notredundant.TheECCSnetworkisredundantbysystemand cantoleratelossofanentireRHRtrain.

RBSUSAR8.3-54August19873.ServiceWaterSystem(SWP)Emergencystartofservicewaterpumps1SWP*P2A,1SWP*P2B,1SWP*P2C,and1SWP*P2Disinhibitediftherespective dischargevalveisnotfullyclosedorthestandbyservice waterinitiationsignalisnotpresent.Thelimitswitchsensingthefullclosedvalvepositiontogeneratetheappropriatefullclosedpermissiveisnot redundant.However,redundancydoesexistatthesystem level.Thestandbyservicewaterinitiationsignaliseither reactorplantcomponentcoolingwaterlooplossofpressure ornormalstandbyservicewaterlooplossofpressure.Each loopisprovidedwithfourpressuresensors.One-out-of-two-taken-twicelogicisusedingeneratingthestartpermissive, thusprovidingadequateredundancy.Theabilityofthestandbyservicewatersystemtoaccommodateanysinglecomponentfailurewithoutaffecting safeshutdownorcooldownorpost-accidentheatdissipation isdetailedinSection9.2.7.3andtheFMEA.Asforcommon modefailures,thesedevicesarequalifiedinaccordancewith RegulatoryGuide1.89.Duringshutdown,eachpumpcanbe verifiedtostartautomatically,onapressuretestsignalto thepressuretransmitters,tomaintainservicewaterpressure greaterthantechnicalspecificationrequirements.8.3.1.1.6.3InterruptingCapacityofSwitchgearandOtherProtectiveDevicesFaultcurrentavailableatallvoltagelevelshasbeenrestrictedtovalueswithinthecertifiedratingoftheinterrupting devicesemployedatthatlevel.Allpossiblesourcesoffault currentcontributionshavebeenconsidered,includingabnormal sourcessuchasanemergencydieselgeneratorontest.

Calculationsofavailableshortcircuitcurrentsarein accordancewithANSIC37.00-1964.8.3.1.1.6.4Grounding Thebalance-of-plantandClass1EDivisionsIandII,bothonsiteandoffsite,powerdistributionsystemsarelow-resistance

grounded.DiscussionofgroundingontheHPCSpowersupply(ESFDivisionIII)iscoveredinSection8.3.1.1.4.2.

RBSUSARRevision138.3-55September20008.3.1.2Analysis8.3.1.2.1GeneralFunctionalDesignBases 8.3.1.2.1.1AuxiliaryElectricalPowerSupplySystems Theauxiliaryelectricalpowersupplysystemsprovideacpowerrequiredfornormalplantoperation,shuttingdownthereactor safely,maintainingasafeshutdowncondition,andoperatingall auxiliariesrequiredforpublicsafetyunderallnormal, transient,andaccidentconditions.Thefollowinggeneral functionaldesignbasesapply:1.Thestandbyauxiliaryelectricalpowersupplysystemsdistributepowertoallloadswhichareessentialfor publicsafety.2.Thenormalandstandbyportionsoftheauxiliaryelectricalpowersupplysystemsarearrangedsothata singlefailuredoesnotpreventsafety-relatedsystems fromperformingtheirintendedsafetyfunctions.133.Thestandby4.16-kVbusesarearrangedsothattheycanbesuppliedfrompreferredorstandbypowersources.4.Sufficientinstrumentationisprovidedtoensureastateofreadinessandperformanceofthestandbyac powersystem.8.3.1.2.1.2StandbyElectricalPowerSupplySystemsThestandbyelectricalpowersupplysystemsaredesignedwithsufficientcapacityandcapabilitytoensurethattheyare capableto,insufficienttime,restoreacpowerintheevent thatthepreferredpowersupplybecomesunavailable.Theyhave theabilitytoreliablysupplytherequiredacloaddemandsof engineeredsafeguardequipmentandcontrolsforpost-accidentas wellassafeandorderlyshutdownoperationssothatthereactor coreiscooledandcontainmentintegrityandothervital functionsaremaintained.Thefollowinggeneralfunctional designbasesapply:

131.StandbyacdieselgeneratorsarehousedinaSeismicCategoryIstructurewithSeismicCategoryIwalls separatingthemsothatanaccidentinvolvingonedoes notinvolveanyothers.Eachfueloiltankiscontained inaseparate RBSUSARRevision138.3-56September2000SeismicCategoryIroom,filledwithsandtoreducethechanceoffirearoundtheoiltank.2.Eachstandbyacdieselgeneratorproducesacpoweratthesamevoltageandfrequencyastheassociated standbystationserviceacpowerdistributionsystem.

Eachiscapableofautomaticstartatanytimeandof continuousoperationatqualifiedload,voltage,and frequencyuntilmanuallystopped.133.Eachstandbyacdieselgeneratoriscapableofbeingmanuallyparalleledwithpreferredstationserviceac powersourceundernormalconditions.Provisionsare madeinthedesigntopreventtheelectrical interconnectionoftheredundantstandbyacdiesel

generators.4.Eachfueloilsystemhasastoragecapacitysuitableforoperatingeachstandbydieselsystematitsmaximum requiredpost-accidentloadconditionsforaminimumof 7days.Thefueloilsystemandstorageistornadoand earthquakeprotected.5.Controlpowerrequiredfortheoperationofeachstandbyacdieselgeneratorissuppliedfromits divisionalstandby125-Vbatterysystem.Standby auxiliaries,suchasfuelpumpsandventilation systems,necessaryforcontinuousoperationofstandby acdieselgeneratorsaresuppliedfromtheirassociated standbybuses.6.Uponlossofpreferredacpowersupplies,eachofthestandbybusesisisolatedfromitspreferredsources, andthestandbyacdieselgeneratorsstart automaticallyandarereadytoacceptloadwithin 10sec.Controls,bothlocalandinthemaincontrol room,areprovidedformanualstartandstopofeach standbyacdieselgenerator.Theoutputofeach standbydieselgeneratorismonitored,andabnormal conditionsarealarmedinthemaincontrolroom.

137.Theacdieselgeneratorsystemisdesignedsothatwithlossofanyoneofthreedieselgeneratorsthe remaininggeneratorsarecapableofsupplyingpowerto sufficientequipmentforasafeshutdownoftheunit undernormaloraccidentconditions.

RBS USAR Revision 16 8.3-57 March 2003 8. Standby bus voltage does not dip below 75 percent of motor-rated voltage at any time during the loading

sequence, and recovers to 90 percent of motor-rated voltage within 40 percent of each load sequence time interval. The ac diesel generator associated with the HPCS does not comply with this portion of Regulatory Guide 1.9; however, its voltage recovery

characteristics are operationally acceptable when

starting its loads (Section 8.3.1.2.2.2). 9. All Class 1E motors, except as noted below, are capable of starting and accelerating their driven equipment with 70 percent of motor nameplate voltage applied to

motor terminals without affecting performance or

equipment life. 16128 The exceptions to this are certain motor-operated valves, motor-operated dampers, Division I and II diesel generator starting air compressors EGA-C4A, EGA-C4B, EGA-C5A and EGA-C5B, 1HVR*UC5, and the motors

driving air compressors 1LSV*C3A and 1LSV*C3B. These

LSV compressors have been environmentally qualified

consistent with IEEE-323 and are capable of starting at 80 percent of motor nameplate voltage. Calculations

have determined, however, that the minimum starting

voltage available at the motor terminals will be 89.63 percent, well in excess of the motors'

capabilities.

16 These Class 1E motor-operated valves, motor-operated dampers, Division I and II diesel generator starting

air compressors EGA-C4A, EGA-C4B, EGA-C5A and EGA-C5B, and unit coolers are capable of starting and accelerating with 80 percent of motor nameplate voltage applied to motor terminals. Calculations have

determined that the minimum starting voltage available

at the motor terminals during the period required for

operation is in excess of the required starting

voltage.8 125 To ensure proper motor-operated valve function under design conditions, an analysis is performed to

determine the torque or thrust that must be delivered

to the valve stem by the motor operator under degraded

voltage conditions (the calculated minimum starting

voltage available).

5 10. All Class 1E motors are capable of continuous operation with 90 percent of motor nameplate voltage applied to

motor terminals.

RBSUSARRevision58.3-57aAugust1992511.Thestandbyacdieselgeneratorsetswillnotbeusedforthepurposeofsupplyingadditionalpowertothe utilitypowersystem(peaking).12.Table8.3-7identifiesnon-Class1Ecircuits(loads)poweredfromClass1Ebusesthataretrippedoffthe busesduringLOCA.Alsoidentifiedarenon-Class1E loadswhichhavebeenevaluatednottoadverselyaffect theClass1Ebusestowhich 5

RBSUSARRevision58.3-57bAugust1992THISPAGELEFTINTENTIONALLYBLANK RBS USAR Revision 17 8.3-58 they are connected should a fault occur at the non-Class 1E load. This will ensure that the Class 1E systems are maintained at an acceptable level with

respect to the requirements of IEEE-308. 8.3.1.2.1.3 Standby Uninterruptible Power Supply Systems (120-V ac) 15 Each of the four (ENB-INV01A, ENB-INV01A1, ENB-INV01B, and ENB-INV01B1) standby 120-V ac uninterruptible power supply systems has two standby alternating current sources and a standby direct current source of power. A standby 125-V dc station battery, the dc source, is a backup to the primary ac source. The primary and alternate ac sources can be selected by an automatic static transfer switch or a manually operated make-before-break bypass switch. The primary ac source is rectified into direct current

which in turn is paralleled with the 125-V dc station battery source. The resultant dc is conducted to an inverter where it is changed to 120-V 60-Hz ac, and then conducted to a static switch.

The inverter frequency is synchronized with the alternate ac

source, but it has its own internal frequency standard which it

uses when the alternate ac source goes beyond normal frequency tolerance. The alternate ac source originates on a 480-V 60-Hz standby bus and is transformed and regulated to 120-V ac. It is then brought to the static switch, and also fed to the manual

bypass switch. The output of the static switch and the alternate ac source are the two inputs to the manual bypass switch (Fig. 8.3-1 and 8.3-

2).The static switch provides a high speed transfer upon loss of inverter power. The manual bypass switch allows the removal of

the inverter or the static transfer switch for maintenance or

testing.15The following general functional design bases apply: 1. The 120-V ac uninterruptible power supply systems consist of independent and redundant power sources, with adequate capacity to supply all essential loads.

The loss of any one source will not affect the bus. 2. The standby 120-V ac uninterruptible power supply systems are structurally designed in accordance with Seismic Category I criteria and are located in Seismic

Category I structures.

RBS USAR Revision 17 8.3-59 3. The standby 120-V ac uninterruptible power supply systems are designed to operate continuously without

anomaly during and after the maximum seismic

accelerations expected for the site. 151 4. Standby 120-V ac uninterruptible power supply systems ENB*INV01A , ENB-INV01A1, and ENB*INV01B (or ENB-INV01B1) are physically and electrically independent (by division) and support redundant loads. It is not possible to parallel the outputs of these systems.

1 158.3.1.2.2 Design Criteria and Standards 8.3.1.2.2.1 ESF Divisions I and II

Criterion 17 The ESF system is designed with sufficient capacity, independence, and redundancy to assure that core cooling, containment integrity, and other vital safety functions are performed in the event of postulated accidents, assuming a single failure. The design of the onsite and offsite electrical power

systems provides compatible independence and redundancy to ensure an available source of power to the ESF loads. Electrical power

from the 230-kV switchyard to the 230/13.8-kV and 230/4.16-kV preferred station service transformers is provided by physically and electrically independent transmission lines. This provides

two independent offsite sources of power to the 4.16-kV standby

buses.Offsite preferred power circuits are connected via normally closed breakers to standby 4.16-kV buses 1ENS*SWG1A and 1ENS*SWG1B (Divisions I and II) at all times. Loss of normal

plant auxiliary supply does not influence or affect the normal 4.16-kV buses 1NNS-SWG1A and 1NNS-SWG1B tie circuits to standby

4.16-kV buses 1ENS*SWG1A and 1ENS*SWG1B. 13The standby 4.16-kV bus 1E22*S004 (Division III) is connected to one of the offsite circuits (Fig. 8.1-4). Loss of all offsite power from the network, although highly unlikely, would result in automatic starting and connection of diesel generator set

1E22*S001G1C to the associated bus within 13 sec.

13The degree of reliability of the power sources required for safe shutdown is very high due to independence and redundancy; it

equals or exceeds all the requirements of Criterion 17.

RBSUSAR8.3-60August1987Criterion18Theauxiliaryelectricalsystemisdesignedtopermitinspectionandtestingofallimportantareasandfeatures,especiallythose whichhaveastandbyfunctionandwhoseoperationisnot normallydemonstrated.AsdetailedintheTechnical Specifications,periodiccomponenttestsaresupplementedby extensivefunctionaltestsduringrefuelingoutages(thelatter basedonsimulationofactionaccidentconditions).These demonstratetheoperabilityofdieselgeneratorsets,battery systemcomponents,andlogicsystems,thusverifyingthe continuityofthesystemsandtheoperationofthecomponents.A completepreoperationaltestoftheonsiteESFpowerdistribution systemisaprerequisitetoinitialfuelloading.RegulatoryGuide1.6ThethreestandbyacpowersystemdivisionseachconsistofadieselgeneratorsetfeedingitsownESFdivisionloadgroup.

Eachloadgrouphasitsowndcpowersystem,energizedbya batteryandbatterychargers.Thethreeloadgroupspossess completeindependence.Thestandbypowersystemredundancyis basedonthecapabilityofanytwoofthethreeloadgroupsto providetheminimumsafetyfunctionsnecessarytoshutdownthe unitandmaintainitinthesafeshutdowncondition.Inadditiontotheprohibitionofsharingstandbypowersystemcomponentsbetweenloadgroups,thereisalsonosharingof dieselgeneratorpowersourcesbetweenunits.EachDivisionIandIIstandbypowersourceiscomposedofasinglegeneratordrivenbyasingledieselenginehavingfast-startcharacteristicsandsizedinaccordancewithRegulatory Guide1.9.ThedesignofthestandbypowersystemisthereforeincompletecompliancewiththeregulationsofRegulatoryGuide1.6.RegulatoryGuide1.9InaccordancewithRegulatoryGuide1.9,theratingsofstandydieselgenerators1EGS*EG1Aand1EGS*EG1Barecontinuousload ratingof3,500kWeach,anda2-hourratingof3,850kWeach, whichexceedsthesumoftheloadsrequired.

RBSUSAR8.3-61August1987Thesequencingoflargeloadsatpredeterminedintervals(Table8.3-2)ensuresthatlargemotorswillhavereachedrated speedandthatvoltageandfrequencywillhavestabilizedbefore thesucceedingloadsareapplied.Thedecreaseinfrequencyand voltagehasbeenverifiedtobewithin95and80percentof nominal,respectively.Recoveryofvoltageandfrequencytowithin10percentand2percentofnominal,respectively,hasbeenverifiedtobe accomplishedwithin40percentofthesequencingintervalof 5sec.Steploadinganddisconnectionofthetotaldiesel generatornameplate-ratingloaddoesnotcausethestandbydiesel generatortoexceed110percentofnormalspeed,thusprecluding aninadvertentoverspeedtrip.Thereliabilityofthestandbydieselgeneratorshasbeensubstantiatedbyanextensivetestprogram.Thetestsverifythe followingdieselfunctions:1.Dieselfaststartcapabilities 2.Loadcarryingcapabilities 3.Loadsheddingcapabilities 4.Abilityofthesystemtoacceptandcarrytheappliedloadsuptoitsratedcapacity5.Long-termnoloadrunningofthedieselunitwithoutanydetrimentaleffects.Thereliabilityofthesystemtostartandacceptloadsinaprescribedtimeintervalhasbeendemonstratedbyprototype qualificationtestdataaugumentedbyanalysistoverifythe abilityoftheRiverBendStationstandbydieselgeneratorsto performtheirintendedfunction,andhasbeenfurtherverifiedby preoperationaltests.Thepreoperationaltestsdescribedin Section8.3.1.1.5.2verifyreliabilityafterplantinstallation.

Full-loadtestshavebeenperformedduringpreoperationaltesting attheRiverBendStationoneachdieselgeneratorsetto demonstratethestartandloadcapabilityoftheunitswithinthe designrequirements.Threehundredvalidstartandloadtests havebeenperformedattheShorehamIunitwithnofailures.A validstartandloadtestisdefinedasastartfromnormal standbytemperatureconditionswithloadingtoatleast 50percentofcontinuousratingwithintherequiredsequencing timeintervals,andcontinuedoperationuntiloperating temperaturesarereached.Thefaststartteststoverifythe dieselreliabilitywereconductedinthefactory.They RBSUSAR8.3-62August1987aredocumentedintheQA/QCverificationdatapackage,togetherwiththeresultsofothertestsdescribed,andprovidea permanent,onsitequalificationrecord.(RefertoNEDO10905 May1973,forreliabilityanalysisoftheHPCSstandbypower

supply.)RegulatoryGuide1.32Thedesignofthepreferredpowercircuitsprovidesfortwoimmediatelyaccessiblecircuitsfromthetransmissionnetworkto theonsitepowerdistributionsystem.ThesizingofClass1Ebatterychargersisbasedontheirabilitytorechargethebatterywithin24hrafterdischargetoadesign minimumlevelof105Vwhilesupplyingthemaximumsteady-state loadwhichoccursinthepost-accidentperiod.Thisisin accordancewiththeregulatorypositionofRegulatoryGuide1.32.

IEEE-308AllelectricalsystemcomponentssupplyingpowertoClass1E electricalequipmentaredesignedtomeettheirfunctional requirementsundertheconditionsproducedbythedesignbasis events.Allredundantequipmentisphysicallyseparatedto maintainindependenceandeliminatethepossibilityofcommon modefailure.AllClass1EequipmentislocatedinSeismic CategoryIstructures.Class1Eequipmentisuniquelyidentifiedbycolorcodingofallcomponentsaccordingtothedivisiontowhichitisassigned,as detailedinSection8.3.1.3.1.

SurveillanceofClass1Eelectricsystemsisincompliancewith IEEE-308,asareallotheraspectsapplicabletothestation design.ThissurveillanceisdetailedintheTechnical

Specifications.

IEEE-323ConformancewithIEEE-323isdescribedinSection3.11.8.3.1.2.2.2HighPressureCoreSprayPowerSupplySystem-DivisionIIICriterion17TheClass1Esystemisdesignedwithsufficientcapacity,independence,andredundancytoensurethatcorecooling, containmentintegrity,andothervitalfunctionsare RBSUSAR8.3-63August1987maintainedintheeventofapostulatedaccident.Thedesignoftheonsiteandoffsiteelectricalpowersystemsprovides compatibleindependenceandredundancytoensureanavailable sourceofpowertotheHPCSsystemanditssupporting

auxiliaries.Electricalpowerfromthetransmissionnetworktothestationisprovidedbytwophysicallyandelectricallyindependent230-kV circuitsasrequiredbythecriterion.Thelossofalloffsite powerfromthenetwork,althoughhighlyunlikely,resultsinan automaticstartingandconnectionoftheHPCSdieselgenerator settotheHPCSbus.Thedegreeofreliabilityofthepowersourcesrequiredforsafeshutdownishigh,becauseoftheindependenceandredundancy,and equalsorexceedsrequirementsofthecriterion.Criterion18Theauxiliaryelectricalsystemisdesignedtopermitinspectionandtestingofallimportantareasandfeatures,especially thosethathaveastandbyfunctionandwhoseoperationisnot normallydemonstrated.AsdetailedintheTechnical Specifications,periodiccomponenttestsaresupplementedby extensivefunctionaltestsduringtherefuelingoutage,the latterbasedonsimulationofactualaccidentconditions.These testsdemonstratetheoperabilityofdieselgeneratorsets, batterysystemcomponents,andlogicsystemsandtherebyverify thecontinuityofthesystemsandtheoperabilityofthe

components.Becausethedieselgeneratorisastandbyunit,readinessisofprimeimportance.Readinessisdemonstratedbyperiodictesting.

ThetestingprogramisdesignedtotesttheabilityoftheHPCS dieselgeneratorsettostartaswellastorununderequivalent loadasrequiredbyRegulatoryGuide1.108.Thisensuresthat coolingandlubricationareadequateforextendedperiodsof operation.Fullfunctionaltestsoftheautomaticcontrol circuitryareconductedinaccordancewiththeTechnical Specificationonaperiodicbasistodemonstratecorrect

operation.Criterion21TheprotectionsystemoftheHPCSpowersupplyisdesignedtobehighlyreliableandtestableduringreactoroperation.TheHPCS dieselgeneratorisonlypartofthehighpressurecorespray system.Ifitfails,theredundantautomatic RBSUSAR8.3-64August1987depressurizationsystemreducesthereactorpressuresothatflowfromLPCIandLPCSsystemsentersthereactorvesselintimeto coolthecoreandlimitfuelcladdingtemperature.RegulatoryGuide1.6TheHPCSdieselgeneratorunitsuppliespowerfortheHPCSandotherauxiliariesasshowninTable8.3-3;therefore,failureof anysinglecomponentoftheHPCSdieselgeneratordoesnot preventthestartupandoperationofanyotherstandbypower supply.Thefailureofanyotherstandbydieselgeneratordoes notimpedetheoperationoftheHPCSdieselgeneratorandits loadgroup,thusmeetingtherequirementsofRegulatory Guide1.6.RegulatoryGuide1.6,Position1ConformanceTheHPCSClass1Eloadsareassignedtoasingledivisionoftheloadgroups.Theassignmentisdeterminedbythenuclearsafety functionalredundancyoftheloadssuchthatthelossofanyone divisiondoesnotpreventtheminimumsafetyfunctionsfrombeing

performed.RegulatoryGuide1.6,Position2ConformanceTheHPCSbus(DivisionIIIoftheacloadgroups)isconnectabletotwodifferent(preferred)offsitepowersources.TheHPCSbus isalsoconnectabletotheHPCSdieselgeneratorasthestandby onsitepowersource(Fig.8.3-3).TheHPCSdieselgeneratorbreakercanbeclosedautomaticallyonlyifallothersourcebreakerstotheHPCSbusareopen.

Thereisnoautomaticconnectiontoanyotherdivisionload

group.RegulatoryGuide1.6,Position3ConformanceThereisnoautomaticormanualconnectionoftheHPCSsystemdcloadgrouptoanyotherdivisionloadgroup.RegulatoryGuide1.6,Position4Conformance1.Thedieselgeneratorsconnectedtotheotherdivisionsoftheloadgroupsarephysicallyandelectrically independentofeachother.Thedieselgenerator connectedtotheHPCSdivisionloadgroupcannotbe automaticallyparalleledwiththedieselgeneratorthat isconnectedtoanotherdivisionloadgroup.

RBSUSAR8.3-65August19872.TheHPCSdieselgeneratorisconnectedtooneindependentdivision.Nomeansexistforautomatically connectingtheHPCSloadgroupwithanyother.3.TheHPCSloadgroupisfedfromonlyonedieselgenerator,asshowninFig.8.3-3.Nomeansare providedfortransferringitsloadstoanyotherdiesel

generator.4.NomeansexistformanuallyconnectingtheHPCSloadgrouptothoseofanotherdivision.TheHPCSload groupisphysicallyandelectricallyindependentofall

others.RegulatoryGuide1.6,Position5ConformanceTheHPCSdieselgeneratorcomprisesofasinglegeneratordrivenbyasingleengine.Thisdieselgeneratorsetneitheroperates inparallelwithanyotherdieselgeneratorsetnorhastandom enginesdrivingthesinglegenerator.RegulatoryGuide1.9ConformancewithRegulatoryGuide1.9isdescribedinthefollowingsubsectionsforeachregulatorypositionofParagraphC oftheguide.RegulatoryGuide1.9,Position1ConformanceTable8.3-3showsthatthecontinuousratingofthediesel generatorisgreaterthanthemaximumcoincidentalsteady-state loadsrequiringpoweratanytime.Intermittentloadssuchas motor-operatedvalvesarenotconsideredforlong-termloads.RegulatoryGuide1.9,Position2ConformanceThelong-termsteady-stateloadshowninTable8.3-3iswithinthecontinuousratingofthedieselgenerator.RegulatoryGuide1.9,Position3ConformanceTheloadrequirementswereverifiedduringthepreoperationaltestsdescribedinSections14.2.12.1.8and14.2.12.1.44.

RBSUSAR8.3-66August1987RegulatoryGuide1.9,Position4ConformanceThedesignfunctionoftheHPCSdieselgeneratorunitisconsideredtobeajustifiabledeparturefromstrictconformance toRegulatoryGuide1.9,regardingvoltageandfrequencylimits duringtheinitialloadingtransient.TheHPCSdieselgenerator loadsconsistofonelargepumpandmotorcombination (approximately2,500hp),onemediumsizepump(450hp),and othermiscellaneousloads;consequently,limitingthemomentary voltagedropto25percentandthemomentaryfrequencydropto 5percentwouldnotsignificantlyenhancethereliabilityofHPCS operation.Tomeettheseregulatoryguiderequirements,adiesel generatorunitapproximatelytwotothreetimesaslargeasthat requiredtocarrythecontinuousfullloadwouldbenecessary.

However,thefrequencyandvoltageovershootrequirementsof RegulatoryGuide1.9aremet.Afactorytestingprogramona prototypeunithasverifiedthefollowingfunctions:1.Systemfast-startcapabilities 2.Loadcarryingcapability 3.Loadrejectioncapability 4.Abilityofthesystemtoacceptandcarrytherequired loads5.Themechanicalintegrityofthediesel-enginegeneratorunitandallmajorsystemauxiliaries.AdetaileddiscussionofthecalculatedvoltageandfrequencytransientresponseisgiveninChapter3oftheGELicensing TopicalReportNEDO10905(HPCSPowerSupplyTopicalReport NEDO10905,Section6,describesprototypeandreliabilitytest

requirements).ThedesignoftheHPCSdieselgeneratorconformswiththeapplicablesectionsofIEEEcriteriaforClass1Eelectrical systemsfornuclearpowergenerationstations(IEEE-308).In addition,aprototypetesthasbeenperformed.Thegeneratorhasthecapabilityofprovidingpowerforstartingtherequiredloadswithoperationallyacceptablevoltageand frequencyrecoverycharacteristics.Apartialorcompleteload rejectiondoesnotcausethedieselenginetotriponoverspeed.

RBSUSAR8.3-67August1987RegulatoryGuide1.29TheHPCSelectricsystemiscapableofperformingitsfunctionwhensubjectedtotheeffectsofdesignbasesnaturalphenomena atitslocation.Inparticular,itisdesignedinaccordance withtheSeismicCategoryIcriteriaandishousedinaSeismic CategoryIstructure.RegulatoryGuide1.32ThedesignoftheHPCSpowersupplysystemconformswiththeapplicablesectionsofIEEEcriteriaforClass1Eelectrical systemsfornuclearpowergenerationstationsIEEE-308.Note:GELicensingTopicalReportNEDO-10905describesprototypeandreliabilitytestrequirements.RegulatoryGuide1.47AllthebypassedtripdevicesprovidealarmsinthemaincontrolroomsothatconditionswhichcanrendertheHPCSdiesel generatorsystemunavailableforautomaticstartare automaticallyannunciatedatthesystemlevelinthemaincontrol room.SeeNEDO10905,Amendment1,p20.RegulatoryGuide1.62ManualcontrolsareprovidedtopermittheoperatortoselectthemostsuitabledistributionpathfromthepowersupplytotheHPCS load.Anautomaticstartsignaloverridesthetestmode.

Provisionismadeforcontrolofthesystemfromthemaincontrol roomaswellasfromanexternallocation.RegulatoryGuide1.75TheHPCSdieselgeneratorisaDivisionIIIdeviceandisseparatedfromequipmentofotherdivisions.Itismarkedwitha DivisionIIInametag.RegulatoryGuide1.100AllClass1EequipmentoftheHPCSsystemisseismicallyqualifiedtotherequirementsofIEEE-344-1971whichwasthe plantrequirementforthisequipment.Are-evaluationtothe requirementsofIEEE344-1975andRegulatoryGuide1.100isin progressandwillbereporteduponcompletion.

RBSUSAR8.3-68August1987RegulatoryGuide1.106Electricmotorsonmotor-operatedvalveshavebeenidentifiedasasignificantintermittentloadonthegeneralacpowersystem.

Thisregulatoryguidedescribesacceptablemethodsofdisabling thermalprotectivedevicesonmotor-operatedvalvemotors.

Thermaloverloaddevicesnormallyinforceduringnormalplant operationarebypassedunderaccidentconditions.RegulatoryGuide1.118Thisregulatoryguidedescribesacceptablemeansforperiodicallytestingthefunctionalperformanceandresponsesoftheelectric powerandprotectionsystems.Therequirementsofthis regulatoryguidearemetwiththefollowingclarifications:PositionC.6-TripofanassociatedprotectivechanneloractuationofanassociatedClass1Eloadgroupisrequiredon removaloffusesoropeningofabreakeronlyforthepurpose ofdeactivatinginstrumentationorcontrolcircuit.

IEEE-279TheHPCSdieselgeneratoranditssupportingauxiliariesconformtoallrequirementsofIEEE-279whichareapplicabletosingular diverseelementsofaredundantset.

IEEE-308AlltheelectricsystemcomponentssupplyingpowertotheHPCS systemconsistofClass1Eelectricequipmentandaredesignedto meettheirfunctionalrequirementsundertheconditionsproduced bythedesignbasisevents.Alltheredundantequipmentis physicallyseparatedtomaintainindependenceandtominimizethe possibilityofacommonmodefailure.AllClass1Eequipmentis locatedinSeismicCategoryIstructures.TheHPCSClass1Eequipmentisuniquelyidentifiedbycolorcodingofthecomponentsaccordingtothedivisiontowhichitis assigned,asdetailedinSection8.3.1.3.1.SurveillanceoftheClass1Eelectricsystemsisincompliancewiththestandard,asareallotheraspectsapplicabletothe stationdesign.

RBSUSARRevision88.3-69August1996 IEEE-323ConformancewithIEEE-323isdescribedinSection3.11.

IEEE-344ConformancewithIEEE-344isdescribedinSection3.10.

IEEE-387TheHPCSpowersupplyunitiscompletelyindependentofotherstandbypowersupplyunitsandmeetstheapplicablerequirements ofIEEE-387.TheHPCSdieselgeneratorunitisdesignedto:1.Operateinitsserviceenvironmentduringandafteranydesignbasiseventwithoutsupportfromthepreferred powersupply.2.Start,accelerate,andbeloadedwiththedesignloadwithinanacceptabletime:a.Fromthenormalstandbycondition, b.Withnocoolingavailable,foratimeequivalenttothatrequiredtobringthecoolingequipmentinto servicewithenergyfromthedieselgeneratorunit,c.Onarestartwithaninitialenginetemperatureequaltothecontinuousrating,fullloadengine

temperature.3.Carrythelong-termsteady-stateloadcontinuously.

4.Maintainvoltageandfrequencywithinlimitsthatwillnotdegradetheperformanceofanyoftheloads composingthedesignloadbelowtheirminimum requirements,includingthedurationoftransients causedbyloadapplicationorloadremoval.85.Withstandanyanticipatedvibrationandoverspeedconditions.Thegeneratorandexciteraredesignedto withstand25percentoverspeedwithoutdamage.

8 RBSUSARRevision88.3-70August19968TheHPCSdieselgeneratorhascontinuousandshort-termratingsconsistentwiththerequirementsofIEEE-387,Section5.1.

88.3.1.2.3ConformanceWithAppropriateQualityAssurance StandardsThequalityassuranceprogramoutlinedinChapter17conformswithRegulatoryGuide1.30,QualityAssuranceRequirementsfor theInstallation,Inspection,andTestingofInstrumentationand ElectricEquipment.TheprogramoutlinedinChapter17includesacomprehensivesystemtoensurethatthepurchasedmaterial,manufacture, fabrication,testing,andqualitycontroloftheequipmentinthe standbyelectricpowersystemconformstotheevaluationofthe standbyelectricpowersystemequipmentvendorqualityassurance programsandpreparationofprocurementspecifications incorporatingqualityassurancerequirements.Theadministrative responsibilityandcontrolprovidedarealsodescribedin Chapter17.Thesequalityassurancerequirementsincludeanappropriatevendorqualityassuranceprogramandorganization,purchaser surveillanceasrequired,vendorpreparationandmaintenanceof appropriatetestandinspectionrecords,certificatesandother qualityassurancedocumentation,andvendorsubmittalofquality controlrecordsconsiderednecessaryforpurchaserretentionto verifyqualityofcompletedwork.Anecessaryconditionforreceipt,installation,andplacingofequipmentinservicehasbeenthesightingandauditingofQA/QC verificationdataandtheplacingofthisdatainpermanent onsitestoragefiles.8.3.1.2.4EnvironmentalQualificationforElectricalEquipmentLocatedinaHarshEnvironmentSeeSection3.11.

RBS USAR (1)T = cable tray; C = conduit Revision 17 8.3-71 8.3.1.3 Physical Identification of Safety-Related Equipment 8.3.1.3.1 Color Coding

Color coded identification is provided for all safety-related equipment including cables, cable raceway, motors, panelboards, motor control centers, load centers, and switchgear. This

identification may be by means of a letter, nameplate, paint, nondeteriorating self-adhesive tapes, permanently affixed tags, or similar means. Nonsafety-related equipment has no color

identification.

Color coding is in accordance with the following:

Equipment and Identification Cable Function Color Letter Raceway Type (1)Nonsafety-Related None (or black) N T or C Safety-RelatedDiv. I Red R T or C Div. II Blue B T or C Div. III Orange O T or C Reactor Protection System

a. Input Channels (Sensors and Logic)

Channel A Red/Yellow S C Channel B Blue/Yellow T C Channel C Orange/Yellow U C Channel D Purple/Yellow V C b. Output Trip Logic Group 1 Red/Green I C Group 2 Blue/Green J C Group 3 Orange/Green K C Group 4 Purple/Green L C 8.3.1.3.2 Equipment Identification

Each piece of equipment, each scheduled tray or conduit, and each scheduled cable, both safety-related and nonsafety-related, has an alphanumeric identification. A code, RBS USAR Revision 17 8.3-72 has been created to identify equipment items.8 The equipment code format for mark numbers explained below is for historical purpose only. The mark numbers created by the

equipment code format have been changed to e quipme nt numbers in the Equipm ent Data Base (EDB). The mark numbers are cross-referenced to the equipm ent numbers in the EDB. The asterisk (*)

was previously used in this equipment code format to indicate safety related. The equipm ent numbers have a separator which is a dash (-), however, this has no significance in relation to its safety classification. Refer to the E DB for the proper equipm ent number and safety classification.

8The equipment code has the following format: X XXX -(or)* XXXXXXXXXXX Unit System QA Category Equipment Code Classification Item identification Example: 1CWS-MOV104 1 - Unit CWS - System code (circulating water system)

- - equipment so designated is Quality Assurance Category II or III MOV - Equipment (motor-operated valve) 104 - Identification Example: 1ENS*SWG1A 1 - Unit ENS - System code (standby 4.160-V switchgear)

• - Equipment so designated is Quality Assurance Category I SWG - Equipment (switchgear) 1A - Identification Safety-related equipment and nonsafety-related equipment other than for the communications system are identified by nameplates which are permanently attached. The nameplates are made of

laminated plastic or metal and engraved with the equipment identification number. The master nameplate for safety-related equipment is color coded. Communications system equipment is identified by stenciling the identification on or adjacent to the

equipment.The cable identification for scheduled cables has the following format: X XXX X X X XXX Unit System Part Color Service Number Code Unit - Identifies the station's unit number.

System Code - Three characters identifying the system.

RBSUSARRevision88.3-73August1996Part-Onesymbolwhichcanbeeitheranalphaoranumericdesignator,e.g.,anMCCcubicle sectionoronepumpofagroup(A,B,C,etc).Color-Analphasymbolindicatingwhetherthecableissafety-relatedornonsafety-related.Service-Analphacharacterindicatingthetypeofserviceforwhichthecablewillbeutilized.Number-Threecharactersassignedtospecifyeachindividualcablenumber.Example:1ENSARH307Allscheduledcablesareidentifiedbypermanentcoloredmarkersattachedtothecableateachendadjacenttothecable alphanumericidentificationmarker.Thebackgroundcolorofthe alphanumericidentificationmarkermaybeusedasthepermanent coloredmarker.Exceptforthecablesrunentirelyinconduit,colorcodeidentificationofacircuitiseitherbythecolorcodedjacket ofthecableorbypaintingthecablejacketwiththeproper coloratintervalsnotexceeding5ft.Cableswithred-orblue-coloredjacketsmaybeusedonunschedulednon-Class1Ecircuitsthatrunexclusivelyin conduit,onlywhenthefollowingmandatoryconditionshavebeen implemented:1.Neutraltagsindicatingnon-Class1Ecircuitsarepermanentlyattachedateachendofthecablerunand whereverthecableisexposed,andfieldquality controlhasverified100percentthatthiscondition hasbeenmet.2.Nocolor-jacketedcableusedforunschedulednon-Class1Eapplicationisallowedtobeterminatedinor passthroughanenclosure(pullbox,junctionbox, cabinet)containingdivisionalClass1Ecircuits.8Cableswithred-orblue-coloredjacketsmayalsobeusedfor directburialcableinstallationsandforthefollowing applications,invarioustypesofraceways,wherethereareonly nonsafety-relatedcircuits:a.Insidethemakeupwaterintakestructure b.Onthesanitarywasteanddisposalsystem8 RBS USAR 8________________

• The closed loop service water site includes all Service Water Cooling (SWC) and Normal Service Water (SWP) cables located

outside the protected area throughout the entire cable length.

8Revision 17 8.3-748c. On the closed loop service water site

• d. Leading Edge Flow Meter (LEFM) transducer cables in the Turbine Building.

At these locations there are no safety-related Category I circuits. No safety-related circuits are installed in direct

burial cable trenches. 8 The raceway identification has the following format: X X X XXX X X X Unit Type Service Number Color Condu/A Condu/N Unit - Identifies the station's unit number.

Type - Character indicating the type of raceway.

Service - An alpha symbol which indicates the service of cable to be carried in the designated raceway. Number - Three numbers assigned to specify the individual raceway.Color - An alpha symbol which identifies the cable to be carried in the designated raceway, safety-related

or nonsafety-related. Condu/A - Conduit identifier. It is a letter or blank when not used. When used for sleeves or duct, it is

numeric or blank when not used. All scheduled cable trays and conduits are identified by raceway identification numbers at each end, and at entries to and exits from enclosed areas. Tray sections longer than 50 ft have an

additional raceway identification number at midspan and at intervals not exceeding 50 ft, while tray sections 15 ft or less have a raceway identification number at midspan. Exposed conduits 8 ft or less have a raceway identification number at

midspan except that for those short sections of conduit where the

identification will not fit in midspan, the conduit is color-coded only (e.g., a short nipple from a junction box to a piece of equipment). Color-coded markers are provided for all Class 1E raceways adjacent to each raceway identification number, or the

numbers themselves may be painted in the appropriate color and at

intervals not exceeding 15 ft.

RBSUSARRevision138.3-75September20008.3.1.4IndependenceOfRedundantSystems8.3.1.4.1General13Therearethreebasicsafety-relatedpowersupplydivisionsthat originateatthe4,160-Vlevel.TheDivisionsI,IIandIII safety-relatedpowersupplysystemscanbeenergizedfrom preferredpowersourceandfromtheirowndieselgenerator.The systemsserveequipmentatthe4,160-V,480-V,and120/240-Vac levels,andthroughinterveningequipmenttheypowerthe125-Vdc

system.13Adedicateddieselgeneratorserveseachdivision.Eachdiesel generatorwithitssupportingauxiliariesisinaseparateroom, asshowninFig.8.3-11.The4160-kVswitchgear,480-Vload centers,480-Vmotorcontrolcenters,abatterychargerforeach battery,125-Vbatteries,anduninterruptiblepowersuppliesare locatedinswitchgearroomswithinthecontrolbuildingandare separatedbydivisionasillustratedbyFig.8.3-9and8.3-10.

Safety-related4.16-kVmotorloads,a480-Vloadcenter,480-V motorcontrolcenters,andloadssubordinatetothe480-Vacand 125-Vdcsourcesarelocatedwithintheauxiliarybuilding,and areseparatedbydivisiontoensureindependenceofsafety-relateddivisions.Additionalsafety-relatedloadsarewithin thecontainmentstructureandatthestandbycoolingtowers, whereseparationbetweendivisionsisalsomaintained.AlltheprecedingequipmentitemsarelocatedwithinSeismicCategoryIstructures.Fireextinguishingsystemsareidentified inChapter9.8.3.1.4.2Class1EElectricEquipmentArrangement RedundantelectricalequipmentandwiringfortheRPS,nuclearsteamsupplyshutoffsystem(NSSSS),andtheESFfunctionsare physicallyseparated,electricallyindependent,andarelocated suchthatnosinglecredibleeventiscapableofdisabling redundantequipmentwhichwouldpreventreactorshutdown,removal ofdecayheatfromthecore,norwhichwouldpreventisolationof thecontainmentintheeventofanaccident.Separation requirementswereappliedtocontrol,power,andinstrumentation forallsystemsconcerned.Rulesgoverningseparationapplyfor Class1EtoClass1E,andforClass1Etonon-Class1Esystems.

Inaddition,thedistancebetweentheelectricalportionsofthe HPCSandRCICsystemsismaximizedwithinthespaceavailableto

ensure the RBS USAR Revision 16 8.3-76 March 2003functional availability of high pressure water for core cooling immediately following a transient. Arrangement and/or protective barriers are such that no locally generated force or missile can destroy any redundant RPS, NSSSS, or ESF functions. Arrangement and/or separation barriers are

provided to ensure that such disturbances do not affect both HPCS

and RCIC. 16Arrangement of wiring/cabling is such as to eliminate, insofar as practical, all potential for fire damage to redundant cables and

to separate the RPS, NSSSS, and ESF divisions so that fire within one division will not damage another division. In addition, approved fire protection features separate wiring and cabling of

the HPCS and RCIC systems from ADS and RHR in the LCPI mode so

that one train of these redundant systems remain free from damage

such that safe shutdown can be achieved as described in chapter

9. The following general rules were followed:

16 1. Routing of Class 1E control, power, and instrumentation cables through rooms or spaces where there is potential for accumulation of large quantities (gallons) of oil

or other combustible fluids through leakage or rupture of lube oil or cooling systems is avoided. Where such routing is unavoidable, only one division of Class 1E

cabling is allowed in any such space. 2. In any room or compartment, other than the cable chases, in which the primary source of fire is of an

electrical nature, cable trays of redundant systems have a minimum horizontal separation of 3 ft if no

physical barrier exists between trays. If a horizontal separation of 3 ft is unattainable, a fire-resistant barrier is installed, extending at least 1 ft above (or to the ceiling) and 1 ft below (or to the floor) line-

of-site communication between the two trays. Totally

enclosed metallic raceway is occasionally used in lieu of barriers at least 1 inch under open cable trays, to

a point where the minimum separation is again maintained. Totally enclosed metallic raceway of

redundant systems maintains a minimum separation

distance of 1 in. 3. In any room or compartment, other than the cable chases, in which the primary source of fire is of an

electrical nature, cable trays of redundant systems have a minimum vertical separation of 5 ft between

vertically stacked trays of different divisions, or

trays of different divisions one RBSUSAR8.3-77August1987abovetheother;however,verticalorcrossstackingoftraysisavoidedwhereverpossible.Incaseswherethe redundanttraysmustbestackedorcrossedonestack abovetheother,andwhenthetraysdonotmeetthe5-ftverticalseparationrequirement,afirebarrieris installedbetweentheredundanttrays.Thebarrier extendsbeyondeithersideofthetraysystem,in accordancewithIEEE-384.Occasionally,totally enclosedmetallicraceway(e.g.,conduit)isusedin lieuofbarriersinthefollowingcases:a.Class1Eladdertypecabletraysarefittedwithprotectivecoverswherever480Vacnon-Class1E cablingor480VacClass1Ecablingofa differentdivisionthanthesubjecttraysis routedinconduitwithin1in.ofthesubject

trays.b.Lowvoltage(120V)power,control,andinstrumentationcabling,whenroutedinclose proximitytoClass1Eladdertypecabletrays,is routedinconduitandmaintainsatleast1-in.

separation.c.TotallyenclosedmetallicracewayofdifferentClass1Edivisionsmaintainsaminimumseparation distanceof1in.Conduitscontainingcablesof differentClass1Edivisionswhichperformthe sameredundantsafeshutdownfunctionsarenot routedincloseproximitytooneanother.4.Anyopeningsinfired-ratedfloorsorwallsforverticalorhorizontalrunsofClass1Ecablingare sealedwithfire-resistantmaterialofequalfire

rating.Theminimumhorizontalandverticalseparationand/orbarrierrequirementsinthecablechasesareasfollows(NOTE:Thereare nocablespreadingroomsinRBS):1.Wherecablesofdifferentdivisionsapproachthesameoradjacentcontrolpanelswithverticalspacingless thanthe3-ftminimum,atleastonedivision'scircuit isrunintotallyenclosedmetallicracewayora barrierisprovidedtoapointwhere3ftofseparation

exists.

RBSUSAR8.3-78August19872.Aminimumhorizontalseparationof1ftismaintainedbetweentrayscontainingcablesofdifferentdivisions wherenophysicalbarrierexistsbetweentrays.Where ahorizontalseparationof1ftisnotattainable, eitherafire-resistantbarrierisinstalledextending atleast1ftabove(ortotheceiling)and1ftbelow (ortothefloor)line-of-sightcommunicationbetween thetwotraysortotallyenclosedmetallicracewayis utilizedtomeetseparationrequirements.3.Verticalstackingorcrossingoftrayscarryingcablesofdifferentdivisionsisavoidedwhereverpossible.

Wherethisisnotpossible,however,thereisaminimum verticalseparationofnotlessthan3ftbetweentrays ofredundantsystems.4.Ifverticalstackingorcrossingofredundanttraysisnecessaryandtheminimum3-ftverticalseparation cannotbemaintained,afirebarrierisinstalled betweentheredundanttrays.Thebarrierextends1ft oneachsideofthetraysystem.Totallyenclosed metallicracewayisusedinlieuofthebarrier,with opencabletray,toapointwheretheminimum separationismaintained.Totallyenclosedmetallic racewaysofredundantsystemsmaintainaminimum separationof1in.WherespatialseparationdistancesarelessthanthosespecifiedaboveinaccordancewithIEEE-384,RBSplant-specific configurationsweretestedandanalysesperformedtojustify reducedseparation.Thetestprogrammethodologyandresultsare documentedinWyleTestReportNo.47618-3.Spatialseparation andbarrierrequirementsareshownondesigndrawingswhichare referencedinSection1.7.TheminimumallowableseparationdistancesarederivedfromthetestedconfigurationsasshowninTable8.3-9.Thefollowing summarizesandevaluatestestresultswhichvalidatetheminimum separationcriteria.InordertoperformatestprogramtoverifytheadequacyofRBSracewayseparationitwasnecessarytodefinetheworstcase electricalfailurethatcouldbepostulatedtooccurina raceway.TheRBSracewayseparationtestprogramwasbasedon thefollowingfailuremodeassumptions:

RBSUSAR8.3-79August19871.Thecableorequipmentinthecircuitdevelopsafaultthatisnotclearedduetothefailureoftheprimary protectivedevices.2.Theworstcaseelectricalfaultisthemostseverecredibleelectricalfaultthatcouldoccur.Theworst-casecurrentisthelesseroflockedrotorcurrent (6XFLA)orthefaultcurrentjustbelowthelongtime tripofthebackupcircuitbreaker.Anadditional10-percentcurrentisaddedtoallowforvarious inaccuraciesoftheinvolveddevices.Theworstcase cableexhibitsthehighesttemperatureforthelongest

duration.3.Forsustainedoverloads,theimpedanceofthefaultadjustsitselfautomaticallytomaintainthefault currentmagnitudeataconstantlevelastheresistance ofthewirechangesduetoheating.4.Theoverloadedcableinitsoverheatedconditionstaysundetectedprecludinganycorrectiveoperatoraction.5.Theworstcaseeffectonnearbyracewaysisestablishedbyacombinationoftemperatureandthefaultduration.Thefaultcurrentmagnitudeof440amperes(400amperes+10percentofuncertainty)usedinthetestprogramwasbasedon thefailuremodeassumptionsdiscussedabove.Thisassumesthat anovercurrentlockedrotorconditionoccursonacablebetweena 480-VacMCCanda480-Vload.Theprimaryovercurrent protectivedevicewhichisamoldedcasecircuitbreakeratthe MCCisassumedtofailtotrip.Thenexthigherlevel(upstream) overcurrentdeviceistheloadcentercircuitbreaker.This currentvaluewasusedforalltestsinvolvingcablesincable racewaysandinfreeair.Inordertoselectthesizeofcableto beusedforconfigurationtests,screeningtestswereperformed todeterminewhichsizecablewhenfaultedwoulddeliverthemost intensetemperatureriseforthelongestdurationtoadjacent cables.Thetestsshowedthatthe#2AWGtriplexcoppercable wastheworstcasecable.TheRBSMCCscontainmoldedcasebreakerswhichprovideoverloadand/orshort-circuitprotectionforeachloaddependinguponthe application.Theloadcenters(LDC)containaircircuitbreakers withsolid-statetripdevices.Thesolid-statetripdevices provideincreasedaccuracyandrepeatabilityoverconventional tripdevices.Theload RBSUSAR8.3-80August1987centerbreakersprovidebothlongandshorttimeovercurrentandinstantaneousshort-circuitprotection.BreakersoftheMCCand LDCaremaintainedonaperiodicbasis.Thismaintenanceensures thatthelikelihoodofacoincidentalfailureoftwoovercurrent devicesinseriesonthesamefeederlineisextremelysmall.Duringeachconfigurationtest,thetargetcableswereenergizedattheirratedcurrentandvoltage.Atthecompletionofeach configurationtest,insulationresistancetestandhighpotential testwereperformedforthetargetcables.Thetargetcables passedtheabovementionedfunctionaltestsinaccordancewith thespecifiedcriteria.Thetestprogramwithaboveassumptionsandinputsforthetargetcablesgeneratedthefollowingresults.600-Vcableinstalledinopenairtraysorconduitsandfaultedwiththeworstcaseinternalfault(440amperes)donotaffect functionability(ampacityorinsulationresistance)ofanytype ofcablesseparatedinaccordancewiththetestconfigurations.

Cablesweretestedinstalledinhorizontaland/orvertical raceways(includingbothcabletrayandconduits)andinfree air.Table8.3-9depictstestedseparationbetweencabletrays, conduits,andcablesinfreeair.Thistablealsoreflectsthe minimumacceptablespatialseparation,withoutuseofbarriers, usedatRBS.Theallowedspatialseparationincludesamarginin termsofdistanceand/ortemperature.AnindependentracewaysystemisprovidedforeachClass1Edivision.Thetraysarearrangedtoptobottombasedonthe cableratedvoltage.1.4.16-kVpower(5,000-Vinsulationclass) 2.Large480-Vpower(600-Vinsulationclass) 3.480-Vpower(600-Vinsulationclass) 4.Control(600-Vand300-Vinsulationclass) 5.Instrumentationcables(300-Vinsulationclass)Nonsafety-related,non-Class1Eelectricsystemsgenerallyhavethesamearrangementofcabletrayswiththeadditionofacable traypositionfor13.8-kVpower(15,000-Vinsulationclass) occupyingtheuppermosttrayposition.

RBSUSAR8.3-81August19878.3.1.4.3ControlofComplianceWithSeparationCriteriaDuringDesignandInstallationCompliancewiththecriteriawhichpreserveindependenceofredundantsystemsisasupervisoryresponsibilityduringboththe designandinstallationphases.Theresponsibilityisdischarged

by:1.Identifyingapplicablecriteria 2.Issuingworkingprocedurestoimplementthesecriteria3.Modifyingprocedurestokeepthemcurrentandworkable4.Checkingmanufacturerdrawingsandspecificationstoensurecompliancewithprocedures5.Controllinginstallationandprocurementtoassurecompliancewithapprovedandissueddrawingsand

specifications.ThenomenclatureusedforequipmentattheRiverBendStationistheprimarymechanismforensuringproperseparation.AllClass1Eelectricalequipmenthasanattachednameplateinscribedwiththeequipmentidentificationandcolor identificationofitsdivision.OtherClass1Epowersystemcomponents,suchascablesandraceways,haveuniquecolorassignmenttoidentifysafety-related systems.Thesecolorsarereadilyapparenttotheoperatorsor maintenancecraftsmensothesafety-relatedcable,raceways,or equipmentcanbeidentified.Nonsafetysystemcircuitsnot associatedwiththesafetycircuitsareeithercolorcodedblack orhavenocoloridentification.Ineverycaseitispossibletodeterminethequalitygroupandseparationclassificationofequipmentfromtheconstruction drawingsandspecifications.Nonessentialequipmenthasbeenseparatedwhereitwasdesiredtoenhancepowergenerationreliability,butsuchseparationisnot asafetyconsideration.Thiswasaccomplishedby administrativelydirectinguseofracewaysystemstoseparate criticalcompanionBOPinstallations,suchasthecondensate

pumps.

RBSUSAR8.3-82August1987Wherethesafety-relatedequipmenthasbeenidentifiedasanessentialsafetydivision,thenomenclatureindicatesa characteristiccolorforpositivevisualidentification.

Likewise,allancillaryequipment,cable,andracewaysmatchthe nomenclatureofthesystemwhichtheysupport.Therearecertainexceptionstotheabovewhereequipmentwhichisnotsafety-relatedisconnectedtoessentialpowersourcesfor functionaldesignreasons.Thesecircuitsareidentifiedin Table8.3-7.Cableusedtoconnectnonsafety-relatedequipment tosafety-relatedsourcesofpowerissafetygradeandqualified androutedasanonsafety-relatedcircuitafterfirsthavingbeen connectedtoaClass1Eprotectivedevice.Ithasnocolor assignment.Thisequipmentisdisconnectedandlockedoutduring anaccidentbyaLOCAsignal,orprotectedbytwoqualified isolationdevices.8.3.1.4.4CableDesign,Analysis,andRoutingofCircuits 8.3.1.4.4.1GeneralFunctionalDesignBases Theproperselectionofcablesandracewayspreservesthereliabilityofredundantsafety-relatedsystemsandconformsto thefollowingdesignbases:1.Thenormalcurrentloadingofallinsulatedconductorsislimitedtothatcontinuousvaluewhichdoesnot causeinsulationdeteriorationfromheating.Selection ofconductorsizesisbasedon"PowerCableAmpacities" and"Ampacities-CablesinOpen-topCableTrays" publishedbytheInsulatedPowerCableEngineers Association(IPCEAPublicationsP-46-426andP-54-440, respectively).Formaintainedspacingofcablesin cabletrays,plant-specifictestsandevaluationshave beenconductedtodemonstratethatspacinglessthan thatspecifiedintheIPCEApublicationsisacceptable aslongasrequiredspacingismaintainedatcabletie-pointintervalsof3ft.Thesetestsandevaluations demonstratedadequatecableampacityandtemperature consistentwithIPCEAguidelines.Forthesmallsizes notcoveredbythepreceding,theNationalElectric Code(NEC)ormorestringentregulationsshallgovern.2.Allcabletraysandsupportsaredesignedtocarrythecablesrequiredwithoutexceedingtheallowable deflectionandyieldstrengthofthematerialsusedin thetraysandtheirsupports.

RBS USAR Revision 22 8.3-83 All cable trays carrying cables for safeguard services are designed to meet Seismic Category I criteria. All raceways installed in Seismic Category I areas are

seismically supported.

3. Cables are specified with consideration of the optimum combination of insulation, fire-resistant, and

radiation-resistant characteristics.

4. Cables are sized and installed so as to limit the temperature rise of conductors to within the

temperature ratings of the cable for any expected overload condition. All power cables are sized and

installed to carry short circuit current until the

first protective device disconnects the source feeding

the short circuit.

8.3.1.4.4.2 Electrical Cable Arrangement

Physical separation is provided between similar components of redundant electrical systems and between power and control circuitry serving or being served from these components.

Redundant protective power and control cables are run on

physically separate cable trays or conduits and follow different routes to and from power sources to loads, and from sensors and

controllers to protective devices. Therefore, an event which

might damage the cables in one set of cable trays or conduit does not affect the redundant cables in the other set of cable trays

or conduit.

Power cables for 15-kV and 5-kV service are stranded copper conductors. Power cables No. 2/0 AWG and larger for 600-V service are stranded aluminum or copper conductors. Smaller power cables and control cables have copper conductors. All cables, where required, are constructed with a radiation-

resistant, 90°C thermosetting-type insulation and an overall

flame-retardant, radiation-resistant jacket.

Cable trays used for 13.8-kV service are identified as "J" trays and those for 4.16-kV are identified as "H" trays. The "J" and the "H" trays are separate from one another. Trays for 600-V or

lower voltage large power cables and some low power cables are

designated "L." Trays for 600-V or lower voltage small power

cables and some control cables are designated "K." Control cables of 120-V ac or 125-V dc, are run in "C" trays or conduit. Low

level analog or digital instrumentation cables are run in "X" trays or in conduit.

In the Drywell, non-divisional, Augmented Quality (but not safety-related), analog instrumentation cables for the main steam line strain gauges are routed both in flexible stainless steel conduit and external to conduit. In the Containment building, the cables are routed in cable tray and rigid conduit.

Segregation in conduit is in a comparable fashion to that employed for trays.

RBSUSAR8.3-84August1987Cablesofredundantsafety-relatedsystemsareisolatedfromeachotherandfromnonsafety-relatedcables.Therearenomedium-orhigh-voltage(480-Vandabove)powercablesinthecontrolbuildingcablechases.ElectricalcablesfortheRPSandothersafety-relatedsystemslocatedinsidethecontainmentstructurearedesignedsothatthe cableisoperablefortherequiredperiodofusageduringall postulatedaccidentenvironments.Cablesinhazardous environmentsareprotectedfromtheenvironmentandagainst physicalorfiredamagetotheextentrequiredfortheservice eitherbyselectionofcableorbychoiceofraceway(e.g.,cable trayswithcovers,metallicconduit).CablesarederatedforgroupingandspacinginaccordancewithIPCEArecommendations.Mediumvoltagecabletraysdonothave morethanasinglelayerofcables.480-Vpowercontroland instrumentationcables,whenroutedincabletrays,areinstalled inaccordancewiththeapplicablecableampacityfactorsandin CategoryIareasdonotextendabovethesiderailsunlessthey areenclosedbyanextendedtraycoveroranengineeringanalysis hasdemonstratedthatelectricalseparationrequirementsarenot compromised.Galvanizedsteel,nonconductingsleevesorblockouts inwallsareusedtotransportcablesthroughconcretewalls.Firedetectionandprotectionsystems,eithermanuallyorautomaticallyinitiated,areprovidedinthoseareasrequiredto preservetheintegrityofthecircuitsforsafety-related services(Section9.5.1).

Theelectricalpenetrations,throughthereactorcontainment vessel,arearrangedingroupstomaintainseparationof electricalcablesandtocomplywiththesingle-failurecriteria.

Thedesignandfabricationofeachtypeofpenetrationassembly isinaccordancewithIEEE-317forElectricalPenetration AssembliesinContainmentStructuresforNuclearFueledPower GeneratingStations.Eachelectricalpenetrationisdesignedto withstandtheenvironmentconditionsatitslocationduringall postulatedDBAs.ConnectionsbetweenfieldwiresandpenetrationassemblyconductorsaremadeinsideSeismicCategoryItermination cabinetsdesignedtowithstandtheenvironmentalconditionsat itslocationduringallpostulatedDBAs.

RBSUSARRevision38.3-85August19903Wiresplicesinsidethereactorbuildingaremadeonlywhere necessaryandareprimarilymadeintheelectricalpenetration terminalcabinets.Allsplicesarequalifiedfortheirintended useasdescribedinSection3.11.Allsplicesaremadein accordancewiththemanufacturer'srecommendedproceduresor approvedequivalentinstructions,andaretestedafter installationbycontinuitymeasurements,andpowercablesplicesareadditionallytestedbyinsulationresistancemeasurements.

Therearenosplicesmadeincabletrays.

3Controlandinstrumentationcableconnectionsforsafety-related CategoryIsystemsandequipmentaremadeonterminatingdevices orbyspliceswhichhavebeenqualifiedfortheirintended functionpursuanttoIEEE-323.8.3.1.4.4.3CableandRacewayScheduling Cableroutingandracewaydesignisaccomplishedmanually.Acomputerprogramwasusedtoassistintheengineering,design, installation,andcontrolofcablerouting,identification,tray, andracewayfill.Themainfunctionsofthisprogramare:1.Thecomputationofallcablelengthsandtotalizingofcabletypes.2.Thecomputationofracewayfillandoverfill indication.3.Toavoidduplication,indicatenumberofrevisionsonaspecificitemandtocheckinformationwithrespectto system,service,andredundancy.4.Toprovideoutputtothefieldintheformofpullandinstallationticketswhichsuppliedallthenecessary informationforinstallationofcablesandracewayand weredesignedtoserveasQualityControl(QC)

documents.5.Toprovidefeedbackfromthefieldthroughsystemstatusinformationwhichalloweddesignerstorevise systemsasrequiredwithaminimumofreworkinthe

field.6.Toprovidestatusofanysystemwithregardtothenumberofcablepullsandtheoveralljobstatus.

RBS USAR Revision 16 8.3-86 March 20038.3.2 DC Power Systems 168.3.2.1 Description - Divisions I and II, Nonsafety 8.3.2.1.1 General 14Station service dc power is available at 125 V and 48 V. There are three ungrounded Class 1E safety-related 125-V dc systems, including Division III discussed in Section 8.3.2.2. There are also six non-Class 1E nonsafety-related ungrounded 125-V systems and one non-Class 1E nonsafety-related ungrounded 48-V system.

Fig. 8.3-6 illustrates these eight 125-V dc and one 48-V dc

systems.14Each system includes a 480-V ac to 125-V dc or 120-V ac to 48-V dc static battery charger with a control panel. Safety-related

chargers are powered from the standby system of their own division. Nonsafety-related chargers are also powered from

safety-related systems to obtain a more reliable source of power

during normal plant conditions, but are tripped on LOCA, with the following exceptions, which are furnished ac power from available

nonsafety-related sources: a. One 480-V ac to 125-V dc battery charger located in the circulating water switchgear house b. One 480-V ac to 125-V dc battery charger located in the services building c. One 120-V ac to 48-V battery charger located in the makeup water switchgear house d. One 480-V ac to 125-V dc battery charger located in the service water cooling switch gear house.

16The 125-V dc systems include a battery charger, a lead acid battery, a 125-V dc distribution switchgear energized from a

battery distribution panel, local and control room instrumentation, and alarm facilities. The battery system

surrenders the identity of its feeders to that of the controlled

equipment or supported system at the first termination after

leaving the distribution switchboard or panel. 7A separate battery charger procured and qualified to IEEE-323 requirements and powered from either a nonsafety-related (black)

power source or a portable diesel generator is provided as a backup battery charger for the Division I, II and III safety-related and three of the nonsafety-related battery chargers.

The backup battery charger's rating is equal to the largest capacity battery charger which it must replace. When the backup

battery charger is to be used, the breaker of the battery 7

RBS USAR Revision 24 8.3-87 charger being removed from service is tripped, removed and placed in the backup charger position. The backup charger breaker is taken from its storage position and placed in the position on its

bus which feeds the bus of the battery charger removed from

service. Manual closing of the two charger breaker completes the

charging circuit.

The backup battery charger breaker's position is monitored in the

main control room, and is tripped upon receipt of a LOCA signal.

Operation of the backup battery charger is under strict administrative control. Credit is taken for this charger in mitigating the consequences of an accident, when used as a

substitute for a Division I or II safety-related battery charger.

Where there is an electrical interface between safety-related switchgear and nonsafety-related equipment, such as chargers and switchgear, automatic breaker tripping by a LOCA signal at the

safety-related switchgear is provided. 12 In the event of an Extended Loss of Alternating current Power (ELAP), at the distribution switchgear for the backup charger, a second breaker that is stored in a normal storage position is used to cross-tie Division I and Division II.

Operation of this breaker and the cross-tying of the Divisions are under strict administrative control. This includes bypassing the LOCA signal to enable closing of the breakers.

The Duty Cycle requirements for the standby batteries are identified in Tables 8.3-4, 8.3-5, and 8.3-6. All dc equipment

is rated to operate between 101 and 140 V dc.

12 The batteries, chargers, distribution switchgear, and certain subordinate equipment such as uninterruptible power supply systems are in separate ventilated enclosures. The enclosures for safety-related equipment are seismic Category I. The other electrical equipment in the room is safety-related and of the

same division.

Those portions of Section 8.3.1.1.1 referring to the physical arrangement, continuity, and integrity of load function is

applicable to the dc systems as well.

8.3.2.1.2 Function

The objective of the safety-related 125-V dc systems (Fig. 8.3-6) is to provide a highly reliable source of dc power and control power for necessary dc loads, such as pumps, valves, relays, control devices, circuit breaker operating mechanisms, inverters of the uninterruptible power supply systems, and similar equipment requiring dc power. The preceding safety-related

devices are required for safe operation of the station and for

safe reactor shutdown under any DBA condition.

Three of the nonsafety-related 125-V dc systems support normal 13.8-kV, 4.16-kV, and 480-V switchgear, uninterruptible power

supply systems, valves, and solenoids.

RBSUSARRevision138.3-88September2000Afourthnonsafety-related125-Vdcsystemsupportstheinformationhandlingsystem,whilethe48-Vdcsystemsupports normal4.16-kVswitchgearandaremotesupervisorycabinet.8.3.2.1.3SystemCapabilities1213Eachsafety-relateddcsystemhasabatterychargerwhichis sizedtosupplyallnormalcontinuoussteady-stateloadsandto restoresimultaneouslyabatteryfromitsendofdutycycle conditiontothefullychargedconditionin24hr.Thebattery chargershaveanequalizingchargevoltageof139Vnominal.The stabilityofthebatterychargeroutputisnotloaddependent.

Eachbatterysystemissizedinconformancewithprinciplesset outinIEEE-308andIEEE-485.BatterycapacitiesforDivisionsI andIIare2100or2150AHeach.Standbybatteries1ENB*BATO1A and1ENB*BATO1BhavetheabilitytosupplyallDBAloadsandall otherloadsnotautomaticallytrippedonaLOCAsignalfor 4hoursandhavesufficientcapacityremainingtoperformthe switchingoperationsnecessarytorestorenormalacanddcpower withthechargerinoperable.

1213Standbybatteries1ENB*BAT01Aand1ENB*BAT01Bfurnishcontrol powertostandby4.16-kVswitchgear,480-Vloadcenters,125-Vdc switchgear,standbydieselgenerators,andstandbyinstrument

buses.131 131Eachnonsafety-relatedsystemhasachargerwithabilitiesas describedintheprecedingparagraphs.Eachbatteryhasthe abilitytosupplyforaminimumof2hrnormalcontinuousloads includinguninterruptiblepowersupplysystemsandallessential dcloadsassociatedwithturbinegeneratorshutdownwithout offsitepower.Thebatterychargershavetheability,upon returnofoffsitepreferredpower,toperformthenecessary switchingoperationtomakethatpoweravailabletotheunit.8.3.2.1.4SupportofBatterySystems Thefacilitiesavailablefornormaloperationofthe125-Vdcsafety-relatedsystemsareshowninFig.8.3-6.Eachsystemhas itsownbatterychargerfornormalsupport,its RBS USAR Revision 24 8.3-89 battery for preferred support, and access to a backup battery charger. The following paragraph is applicable to normal design basis conditions but may be procedurally changed as described i n Section 8.3.2.1.1 in the event of an Extended Loss of Alternating current Pow er (ELAP) A procedural configuration that maintains at least two empty circuit breaker cubicles or an empty cubicle and open circuit breaker is provided to prevent cross-connections between

independent battery systems through the backup battery charger switchgear 1BYS-SWG01D. No single failure can jeopardize the

safety of redundant loads. The 125-V dc nonsafety-related systems are arranged similarly to the 125-V dc safety-related systems and are shown in Fig. 8.3-6.

8.3.2.1.5 Ventilation 8 Each battery associated with the Division I and II standby diesels is located in its own independently ventilated room to keep the gases produced due to the charging of batteries below an explosive concentration, and to keep the room temperature to a level that allows the battery to supply its required current.

The ratings of the batteries were initially established based on

a 24-hour average electrolyte temperature of 77°F.

8 8.3.2.1.6 Instrumentation and Alarm Important system components are either alarmed on failure or capable of being tested during service to detect faults.

Indicators are provided to monitor their status in the main

control room. The station operating procedures provide for system status checks at every shift change that include the

charging status of batteries in the unlikely event that a battery charger should fail without annunciating the condition in the

control room.

Control of the battery chargers and the distribution switchgear is local. The Division I and II dc power system includes the

following monitors and alarms: 1.Main Control Room Annunciation and Monitors a.Battery current (ammeter-charge/discharge)b.Dc bus voltage (voltmeter) c.Dc bus voltage low alarm (set above the open circuit voltage) d.Dc bus voltage low-low alarme.Dc bus ground fault alarm (for ungrounded systems)

RBSUSARRevision88.3-90August1996f.DcBusbatterybreakeropenalarmg.DcBusbatterychargeroutputbreakeropenalarm h.Batterychargertroublealarm i.Backupchargerbreakeropenalarm j.Supplyordistributionbreakerovercurrenttrip alarm6k.Voltagetogroundforbothpolaritiesatswitchgear 62.LocalAnnunciationandMonitorsa.Batterychargeroutputcurrent(ammeter) b.Batterycurrent(ammeter-charger/discharger) c.Batteryvoltage(voltmeter) d.Batterychargeroutputvoltage(voltmeter) e.Batterychargerovervoltage f.Batterychargerlowacsupplyvoltage g.Batterychargerovercurrent h.Batterychargertemperaturehigh63.Local(RemoteShutdownPanel)a.(1)WhiteindicatinglightforlocalENB 6TheNon-Class1Edcpowersystemincludesthefollowingmonitors andalarms:81."125Vdcbatterychargertrouble"alarmlocatedinthemaincontrolroomandlocalsupervisorycontrolpanel (1BYS-CHGR1C)annunciatesintheeventofactuationof localalarmsonthebatterycharger.8 RBSUSARRevision108.3-91April199888102.TheBatterychargerBXY-CHGR1provides"48-Vdcbatterychargertrouble"alarmlocatedinthemaincontrolroomand localsupervisorycontrolpanel63.TheBatterychargersBYS-CHGR1A,1BandIHS-CHGR1Dprovide"Batterychargertrouble"alarmlocatedinthemaincontrol

room.6106"125-Vdcbatterytrouble"alarmlocatedinthemaincontrolroom annunciateintheeventofthefollowingconditionson

1BYS*CHGR1D:1.460-Vacinputundervoltage 2.125-Vchargerovervoltage 3.Chargercabinettemperaturehigh 4.Chargeroutputovercurrent 5.INJS-ACB453breakerintestposition 6Uninterruptiblepowersupplieshavebeenspecifiedtoinclude protectivecircuitrywhichprotectsinternalcomponentsfromdc inputvoltagespikeswhichmayhaveoriginatedonthedcpower

system.8.3.2.1.7MaintenanceandTesting Thestationbatteriesandotherequipmentassociatedwiththe125-Vdcsystemsareeasilyaccessibleformaintenanceand testing.Thebatterieswillbeperiodicallycheckedforspecific gravityandindividualcellvoltages.Anequalizing (overvoltage)charge,whererecommendedbythebattery manufacturer,isappliedtobringallcellsuptoanequal voltage.Overaperiodoftime,theabove-mentionedtestswill revealaweakorweakeningtrendinanycellandreplacementis madeifnecessary.Periodically,thebatterychargeris disconnectedandtheabilityoftheunitbatterytomaintain voltageandassumethedcloadisverified.Thistestuncovers anyhigh-resistanceconnectionsorcellinternalmalfunctions.

Thenormalstationbatteriesandthestandbybatteriesfor DivisionsI,II,andIIIhaveaccesstoabatteryloadtester,as showninFig.8.3-6.Testing RBS USAR Revision 16 8.3-92 March 2003 16complies with IEEE-308, Criteria for Class 1E Electrical Systems for Nuclear Power Generating Stations. Periodic testing

requirements of each safety related battery system during normal

or accident periods of operation are described in the Technical

Specifications.

16The battery chargers may be operated with the battery disconnected since the charger's stability is not load dependent.

With the battery disconnected the charger's regulation is

0.5 percent

from no load to full load and ripple does not exceed

105 millivolts (rms).

The only foreseen mode of electrical operation during which the battery chargers would supply power to the dc switchgear loads

without the batteries also being connected to the dc switchgear

load would occur during periodic battery discharge tests. 8.3.2.2 Description - Division III (HPCS)

8.3.2.2.1 General The objective of the 125-V dc power system (Division III) is to provide a reliable, continuous, and independent 125-V dc power

source of control and motive power as required for the HPCS

system logic, HPCS diesel generator set control and protection, and all Division III related control. A Class 1E battery charger is provided for the battery. The 125-V dc system is classified as Class 1E. The Division III 125-V dc

system is independent of all other divisional batteries and there is no manual or automatic connection to any other battery system.

The battery is not shared with any other unit. 8.3.2.2.2 HPCS DC Loads 12The 125-V dc power is required for HPCS diesel generator field flashing, control logic, and for the control and switching function of breakers. The Duty Cycle requirements for the

Division III battery are identified in Table 8.3-6. 8.3.2.2.3 Battery and Battery Charger 14The 125-V dc system for the HPCS power supply has a 60 cell lead acid battery (825 AH at 8 hr), one battery charger and a distribution panel with molded case circuit breakers. The HPCS battery charger output capability is at least 50-A dc at a minimum float voltage of 130.2 Vdc. Independent calculations

verify that the HPCS battery charger has the capability to supply

all normal continuous steady-state 12 14 RBSUSARRevision138.3-93September20001312loadsandsimultaneouslyrestoretheDivisionIIIbatteryfrom itsendofDutyCycleconditiontothefullychargedconditionin 8hours.1312The125-VdcsystemequipmentisdesignedasClass1Ein accordancewithapplicableclausesofIEEE-308.Itisdesigned sothatnosinglefailureinthesystemwillresultinconditions thatpreventsafeshutdownoftheplant.Theplantdesignand circuitlayoutfromthedcsystemsprovidesphysicalseparation oftheequipment,cabling,andinstrumentationessentialtoplant

safety.AsshowninFig.8.3-6,thebatteryisassociatedwithitschargersanddistributionpanel.Thebatteryislocatedinits ownventilatedroom.Allthecomponentsofthedcsystemsare housedinaSeismicCategoryIstructure.8.3.2.2.4125-VDCSystemsIdentification Fig.8.3-6showsthe125-Vdcsystems.ThebatteryfeedsintodistributionpaneltoservethevariousdcloadsfortheHPCS system.Thebatterychargerisfedfromthe480-Vacengineered safetyfeaturesmotorcontrolcenterwhichissuppliedbythe HPCSdieselgeneratorbus.8.3.2.2.5BatteryCapacity12Theampere-hourcapacityandshorttimeratingofthebatteryis inaccordancewithcriteriagiveninIEEE-308andIEEE-485,and isadequatetosupplyallelectricalloadsrequireduntilac powerisrestoredfortheoperationofthebatterychargers.The batteryhassufficientstoredenergytooperaterequired connectedessentialloadsforaslongaseachmaybeneeded duringalossoftheacbussupplyingthebatterychargersunder normaloremergencyconditions.Capacityislargeenoughtocope withLOCAconditionsoranyotheremergencyshutdown.Each distributioncircuitiscapableoftransmittingsufficientenergy tostartandoperateallrequiredloadsinthatcircuit.

128.3.2.2.6ChargingTheClass1Echarger1E22*S001CGRfortheHPCSdcsystemisfedfromtheHPCSmotorcontrolcenter(MCC)andiscapableof carryingthenormaldirect-currentsystemloadand,atthesame time,keepingthebatteryinafullychargedcondition.The sizingofthebatterychargermeetsIEEE-308.

RBSUSARRevision148.3-94September2001 14ThemaximumequalizingchargevoltagefortheHPCSbatteryis limitedbythemaximumoperatingvoltageoftheconnected equipmentto140Vdc.Performanceofanequalizingchargeat maximumvoltagewillresultinnodamagetoconnectedequipment.

14*7AseparatebatterychargerprocuredandqualifiedtoIEEE-323 requirementsandpoweredfromeitheranon-safety-related(black) powersourceoraportabledieselgeneratorisprovidedasa backupbatterychargerfortheDivisionI,IIandIIIsafety-relatedandthreeofthenonsafety-relatedbatterychargers.The backupbatterycharger'sratingisequaltothelargestcapacity batterychargerwhichitmustreplace.Whenthebackupbattery chargeristobeused,thebreakerofthebatterychargerbeing removedfromserviceistripped,removedandplacedinthebackup chargerposition.Thebackupchargerbreakersistakenfromits storagepositionandplacedinthepositiononitsbuswhich feedsthebusofthebatterychargerremovedfromservice.

Manualclosingofthetwochargerbreakerscompletesthecharging

circuit.Thebackupbatterychargerbreaker'spositionismonitoredinthemaincontrolroom,andistrippeduponreceiptofaLOCAsignal.Operationofthebackupbatterychargerisunderstrictadministrativecontrol.Nocreditwastakenforthischargerin mitigatingtheconsequencesofanaccident.Wherethereisanelectricalinterfacebetweensafety-relatedswitchgearandnonsafety-relatedequipment,suchaschargersand switchgear,automaticbreakertrippingbyaLOCAsignalatthe safety-relatedswitchgearisprovided.12TheDutyCyclerequirementsforthestandbybatteriesare identifiedinTables8.3-4,8.3-5,and8.3-6.Alldcequipment isratedtooperatebetween101and140Vdc.

12Thebatteries,chargers,distributionswitchgear,andcertain subordinateequipmentsuchasuninterruptiblepowersupply systemsareinseparateventilatedenclosures.Theenclosures forsafety-relatedequipmentareseismicCategoryI.Theother electricalequipmentintheroomissafety-relatedandofthe samedivision.ThoseportionsofSection8.3.1.1.1referringtothephysicalarrangement,continuity,andintegrityofloadfunctionis applicabletothedcsystemsaswell.

7 RBSUSARRevision128.3-94aDecember19998.3.2.2.7VentilationThebatteryroomisindependentlyventilatedtokeepthegasesproducedduetothechargingofthebatterybelowanexplosive

concentration.8.3.2.2.8MaintenanceandTesting Designandinstallationofthe125-Vdcsystemfacilitatesperiodicmaintenanceteststodeterminetheconditionofeach individualcell.Cellscanbecheckedforliquidlevel,specific gravity,andcellvoltage.Performancedischargetestscanbe conductedasrequired.Batterychargersarealsoperiodically checkedbyvisualinspectionandperformancetests.TestingoftheDivisionIII125-Vdcbatteriesincludesthe following:1.Thespecificgravity,voltage,andtemperatureofthepilotcellofeachbatteryaremeasuredandloggedin accordancewiththetechnicalspecification.122.Every3months,voltagemeasurementsofeachcelltothenearest0.01V,specificgravityofeachcell,and temperatureofrepresentative(atleastoneoutofsix connectedasdiscussedinTSSRBases3.8.6.3)cells aremade.Thesemeasurementsarelogged.

123.Onceeachrefuelingcycle,thebatteriesaresubjectedtoaservicetest.Thespecificgravityandvoltageof eachcellaremeasuredafterdischargeandlogged.8.3.2.2.9TestRequirementsofStationBatteries ProvisionsaremadeinthedcpowersystemsothatsurveillanceandservicetestscanbeperformedinaccordancewithIEEE-450.8.3.2.2.10InstrumentationandAlarm Importantsystemfunctionsareeitheralarmedonfailureorcapableofbeingtestedduringservicetodetectfaults.

RBSUSARRevision78.3-94bJanuary1995THISPAGEINTENTIONALLYLEFTBLANK RBS USAR Revision 16 8.3-95 March 2003 Indicators for critical parameters are provided to monitor their status in the main control room.Additionally, station operating procedures provide for system status monitoring at every shift change that will include a check of the charging status of the battery in the unlikely event that

the battery charger fails in a manner which is not alarmed in the

control room.

Main control room instrumentation includes a voltmeter, and an ammeter for each dc system. Control of the battery chargers and the distribution switchgear is local. The dc power system

includes the following alarms and monitors: 1. "125 V dc System Trouble" alarm located in the main control room annunciates in the event of: a. Battery output breaker trip

b. 125 V dc bus ground, or

c. 125 V dc bus undervoltage.

2. "HPCS Battery Charger Trouble" alarm located in the main control room annunciates in the event of: a. Battery charger output breaker trip

b. Battery charger high output voltage, or

c. Battery charger loss of ac power supply.

3. "Battery Trouble" alarm located on the local diesel-generator control panel annunciates in the event of: a. 125 V dc bus ground, or

b. 125-V dc bus undervoltage.

4. The following voltmeters are provided to monitor 125 V dc supply voltage: a. 125 V dc voltmeter in the main control room 16 b. 125 V dc voltmeter locally at battery charger 16 RBS USAR Revision 16 8.3-96 March 200316 c. 125 V dc voltmeter at local diesel-generator control panel.

16 5. The following ammeters are provided to monitor 125 V dc system load current: a. Ammeter in the main control room

b. Ammeter at local diesel-generator control panel

c. Ammeter locally at battery charger.

8.3.2.3 Analysis - Divisions I and II

8.3.2.3.1 Compliance 8.3.2.3.1.1 General Functional Design Requirements 13During normal operation, the 125-V dc loads (Fig. 8.3-6) are fed from the battery chargers, with the batteries floating on the 125-V dc system. Upon loss of ac power to the battery chargers, the entire dc load is supported from the batteries until ac power

is restored from the preferred transformers or standby diesel generators, to energize the battery chargers. The 125-V dc

systems are designed on the following general functional bases:

13 1. The 125-V dc systems are designed to meet the single failure criterion in which failure of any single

component of the system does not result in a failure

which could prevent any safety-related system from performing its function. This is accomplished by

providing a separate battery, distribution panel, and

battery charger for each system. 2. Each battery serving a standby 4.16-kV ac bus is designed in accordance with Seismic Category I

criteria. 3. Batteries serving standby 4.16-kV ac buses are housed in a Seismic Category I structure with Seismic Category I walls separating them. Allowances are made

for proper ventilation of the battery rooms. 4. There are no nonsafety-related loads on safety-related 125-V dc systems.

RBSUSAR8.3-97August19878.3.2.3.1.2DesignCriteriaandStandardsCriterion17TheClass1Edcpowersystemisdesignedtopermitthefunctioningofstructures,systems,andcomponentsimportantto safety.Inaddition,thedcpowersourcesandthedc distributionsystemhavesufficientindependence,redundancy,and testabilitytoperformtheirsafetyfunctions,assumingasingle failure,tomeettherequirementsofGDC17.Criterion18TheClass1Edcpowersystemisdesignedtopermitperiodicinspectionandtestingtoassesstheconditionofthesystem's componentsandtheircapabilitytoperformtheirintended functionsinordertomeettherequirementsofGDC18.RegulatoryGuide1.6TheClass1Edcpowersystemconsistsofthreeredundantandindependentdcsystems,eachconsistingofabatterywithitsown chargeranddistributionsystem.TheClass1Edcredundantload groupshavenoautomaticconnectiontoanyotherloadgroupand noprovisionsforautomaticallytransferringloadsbetweenthese redundantloadgroups.Abackupbatterychargerisredundantto theoperatingchargersdescribedinSection8.3.2.1.1and supplies125-Vdcpowerrequirementsduringmaintenanceperiods.

ThedesignmeetstheindependencerequirementsofRegulatory Guide1.6.RegulatoryGuide1.32TheClass1Edcsystemisoperatedatanormalfloatchargevoltageleveltomaintainthebatteriesinafullycharged condition.Thebatterychargersassociatedwitheachstandby batteryareratedtosupplythelargestcombineddemandsofthe varioussteady-stateloadsandthechargingcapacitytorestore thebatteryfromthedesignminimumchargedstatetothefully chargedstateirrespectiveofthestatusoftheplantwhenthese demandsoccur,inordertomeettherequirementsofRegulatory Guide1.32.BothDivisionIandIIbatteriesaresizedtocarry safetyloadsforatleast4hrfollowinglossofallacpower.

Eachbatteryvoltageleveliscontinuouslymonitoredand displayedinthemaincontrolroom.Lowvoltageandlowcharging currentarealarmedinthemaincontrolroom.

RBS USAR Revision 22 8.3-98 IEEE-450 The reliability of the dc supplies are assured by periodic

discharge tests of the batteries, as described in IEEE-450. An exception has been taken to IEEE-450, in that, the specified maximum interval of 18 months between battery service tests has been extended to 30 months.

8.3.2.3.1.3 Conformance With Appropriate Quality Assurance Standards

See Section 8.3.1.2.3.

8.3.2.3.2 Independence of Redundant Systems

See Section 8.3.1.4.

8.3.2.3.3 Physical Identification of Equipment

See Section 8.3.1.3.

8.3.2.3.4 Test Documentation to Qualify Electrical Equipment

See Section 8.3.1.2.4.

8.3.2.4 Analysis

8.3.2.4.1 General DC Power System

8.3.2.4.1.1 Compliance With General Design Criteria and Regulatory Guides

The design of the 125-V dc system for the engineered safety features provided for this plant are based on the criteria

described in IEEE-308 and Regulatory Guide 1.32.

The 125-V dc systems, including the power supply, distribution system, and load groups, are arranged to provide dc electric power for control and switching of the components of Class 1E

systems.

Batteries consist of industrial-type storage cells designed for the type of service in which they are to be used. Ample capacity is available to serve the loads connected to the system for the

duration of the time the alternating current is not available to the battery charger. Each division of Class 1E equipment is provided with a separate 125-V dc system, so as to avoid a single

failure involving more than one system.

Each battery charger has enough power output capacity for the

steady-state operation of connected loads required RBSUSAR8.3-99August1987duringnormaloremergencyoperation(whicheverislarger),whilemaintainingitsbatteryinafullychargedstate.Eachbattery chargersupplyhasenoughcapacitytorestorethebatteryfrom thedesignminimumchargetoitsfullychargedstatewhile supplyingnormalsteady-stateloads.Thenormalbatterycharger supplyisfromengineeredsafetyfeaturebuses.Thebackup batterychargerissuppliedfromanon-ESFsource.Sincethedc powersystemsareoperatedungrounded,agrounddetectionfeature isprovided.Indicatorsareprovidedtomonitorthestatusofthe batterychargersupply.Thisinstrumentationincludesindication ofoutputvoltages,outputcurrent,batterygroundstatus,and maincircuitbreakerposition.Busundervoltageisannunciated inthemaincontrolroom.Batterychargersareprovidedwith disconnectingmeansandfeedbackprotection.Periodictestsare performedtoassurethereadinessofthesystemtodeliverthe powerrequired.8.3.2.4.2HPCS-DivisionIII-ESFDCSystem The480-VacfeedtotheClass1EbatterychargerisfromtheHPCSmotorcontrolcentertomaintainfunctionalassociationsuch thatthebatterycancarrytheHPCSdcloadfor2hr.

Probabilityofasystemfailureresultinginprolongedlossofdc powerisextremelylow.Importantsystemcomponentsareeither self-alarmingonfailureorcapableofbeingtestedduring servicetodetectfaults.Thebatteryislocatedinitsown ventilatedbatteryroom.Allabnormalconditionsofselected systemparametersimportanttosurveillanceofthesystem annunciateinthemaincontrolroom.Automaticcrossconnections betweentheHPCS125-Vdcsystemsandotherdcsystemsarenot provided.ControlpowerforthebreakersintheHPCSswitchgear isfromtheHPCSbatteryensuringthefollowing:1.TheunlikelylossofHPCSdcpowersupplywillnotjeopardizethesupplyofoffsiteoronsitepowerto otherengineeredsafetyfeaturebuses.2.ThedifferentialrelaysandalltheinterlocksassociatedwithHPCSarefromtheHPCS125-Vdcsystem only,therebyeliminatinganycrossconnectionsbetween theredundantdcsystems.8.3.3FireProtectionforCableSystemsThebasicconceptoffireprotectionforcablesystemsisthatitshouldbedesignedintotheinstallationratherthanaddedonto thefinishedproduct.Accordingly,thepertinentfeatureshave beenpreviouslydiscussedunderthe RBSUSAR8.3-100August1987analysisconductedtodetermineifthepowersystemdesignmetapplicablecriteria(Section8.3.1.4.4).Byuseoffire-resistantcablesandconservativeapplicationasregardsampacityandcarefulrouting,bothwithregardtopath andracewayconstruction,fireresistanceisbuiltintothecable systems.Externalfireprotectionanddetectionisdiscussedin Section9.5.1.

RBSUSAR8.3-101August1987References-8.31.Henrie,D.K.andSubramanian,C.V.,SeismicQualificationReviewTeam(SQRT),TechnicalApproachforRe-Evaluationof Equipment,NEDE-24788-2,December1982.2.LetterfromJ.E.Booker,GulfStatesUtilitiesCompany,Beaumont,Texas,toH.R.Denton,U.S.NuclearRegulatory Commission,Washington,DC,February10,1984.3.LetterfromJ.E.Booker,GulfStatesUtilitiesCompany,Beaumont,Texas,toH.R.Denton,U.S.Nuclear RegulatoryCommission,Washington,DC,April11,1985(GSU LetterNo.RBG-20684).