ML20237B279

Rev 2 to Rept on Conformance of Nuclear Svc Electrical Bldg & Diesel Generator Bldg Electrical Installation to Reg Guide 1.75

ML20237B279
Person / Time
Site:	Rancho Seco
Issue date:	12/01/1987
From:	SACRAMENTO MUNICIPAL UTILITY DISTRICT
To:
Shared Package
ML20237B267	List: ML20237B265 ML20237B279
References
RTR-NUREG-1286, RTR-REGGD-01.075, RTR-REGGD-1.075 ERPT-E0220, ERPT-E0220-R02, ERPT-E220, ERPT-E220-R2, TAC-63030, NUDOCS 8712160146
Download: ML20237B279 (36)

Text

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ERPT E O220 DEC 0 81987 ENGINEERING REPORT ERPT-E0220 REPORT ON CONFORMANCE OF NSEB AND DG BUILDING ELECTRICAL INSTALLATION TO REGULATORY GUIDE 1.75 SACRAMENTO MUNICIPAL UTILITY DISTRICT i

l REVISION 2 December 1,1987 l 1

l 8712160146 871208 PDR P

ADOCK 05000312 PDR l

ERPT r, o2,20 TABLE OF CONTENTS PAGE I. INTRODUCTION 1 II. GENERAL REQUIREMENTS 2 III. DEFINITIONS 3 IV. EQUIPMENT SEPARATION 5 V. RACEWAY SEPARATION 6 j VI. INTERNAL SEPARATION 8 VII. RACEWAY / CIRCUIT IDENTIFICATION 9 i VIII. REFERENCES 11 APPENDICES  !

A Clarifications / interpretations of Regulatory Guide 1.75 A-1 B Analysis of Regulatory Guide 1.75 Separation Requirements B-l Based on the Tests for Another Plant LIST OF FIGURES Figure 1 Electrical Gear Layout / Separation. (2 sheets) 2 Acceptable Separation Between Conduits and Cable Trays (3 sheets) in the NSEB and D/G Building.

LIST OF ATTACHMENTS Attachments 1

1 USAR Chapter 8, Section 8.2.2.11 (5 sheets) l i

SPT E 0220 a I. INTRODUCTION The District submitted License Amendment 147 for Technical Specification changes with Reference 1. This license amendment was required to revise the Technical Specification due to modifications that were made to the Electrical Distribution System. The modifications include addition of:

. Two new TDI diesel generators

. Electrical switchgear

. Motor control centers and distribution panels

. Batteries

. Battery chargers

. 120V ac uninterruptible power supplies

. Diesel Generator Building

. Nuclear Service Electrical Building In reviewing this Technical Specification, the NRC raised questions on the separation criteria used in the design and installation of the hardware for the modifications (see Reference 2, NRC Question 16 in Enclosure 10). The separation criteria used are described and documented in this report.

l The District used the separation criteria listed in the USAR

, (Attachment 1) for modifications in existing buildings and hardware l

(installed prior to commercial operation). For new building and hardware, the District has established new criteria to meet the intent of Regulatory Guide 1.75. This document describes in detail the criteria used.

The electrical equipment and raceway for safety related systems are segregated into two redundant power load groups designated as Train "A" and Train "B", and four redundant instrumentation and control Channels "A", "B", "C", and "D".

Train "A" supplies 480V ac power to instrumentation and control Channel s "A" and "C".

Train "B" supplies 480V ac power to instrumentation and control Channel s "B" and "D".

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ERPI E 0220 j II. GENERAL REQUIREMENTS i

1. The Class 1 redundant Train "A" and "B" equipment and trays are located in rooms separated by 3-hour fire walls. Also separate underground ducts and manholes are used for each of the Trains "A" l and "B". Separation of Trains "A" and "B" exceeds the minimum J requirements of Regulatory Guide 1.75.

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2. All the cables in open raceways meet the requirements of the vertical tray flame test of IEEE 383.

3. To meet Regulatory Guide 1.75 requirements, cable splicing is I prohibited in the conduits, trays and underground ducts. .l

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4. The design basis for cable tray fill is to limit the depth of power cables, limit the total weight of cables, and prevent overflow from the tops of the trays.

5. No high energy lines are in the NSEB or the Diesel Generator Building. Furthermore, arrangement and/or protective barriers preclude locally generated forces or missile hazards from damaging redundant channels.

6. The Train "A" and "B" areas of the NSEB are served by separate Class 1 HVAC systems. In addition, each of the battery rooms has its own Class 1 exhaust system ("A" and "C" are fed from Train "A",

and "B" and "D" are fed from Train "B").

7. The Train "A" and "B" areas of the Diesel Generator Building are served by separate Class 1 ventilation systems.

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ERPT E Q Q 2 Q.

III. DEFINITIONS

1. Diesel Generator Building: Safety class structure housing Train A and B redundant TDI Diesel Generators and their auxiliaries.

2. Nuclear Service Electrical Building (NSEN: Safety class structure designed to house and protect addicional electrical power distribution equipment (switchgear, MCC, batteries, battery chargers, inverters, transformers, panels, etc.) related to Licensing Amendment 147.

3. Rigid Conduit: Rigid conduit is galvanized steel conduit. The conduit fittings and pull boxes which are a part of the rigid .

conduit system are also included. I

4. Enclosed Raceway: Enclosed raceway includes rigid conduit, liquid tight flexible metal conduit, EMT, solid bottom. cable trays where separation is required from the raceway directly below, and solid covered cable trays where separation is required from the raceway directly above.

5. Low Energy Circuits: The cables carrying only milliampere signal current, at potentials not exceeding 120V ac or 125V de, are ,

designated as low energy circuits.  !

6. Instrumentation Cables: Cables that are used for low energy ci rcuits, including:

. Coax cables

. Shielded instrumentation cables

. Fiber optic cables

7. Equipment

Enclosures:

Equipment enclosures include cubicles or compartments of control panels, cabinets, control consoles, MCC's, load centers, switchgear and terminal boxes used for electrical equipment.

8. Class 1 Group: The Class 1 group consists of two Class 1 redundant trains and four Class 1 redundant channels. Physical separation of cables, wires, and raceways belonging to redundant trains / channels is maintained. The redundant trains and channels are defined as follows:

A. Train "A" It consists of Safety Related System redundant power load group "A" and Supplies Class 1 Diesel Generator backed power to channels "A" and "C". Train "A" and Channel "A" circuits share common raceways of the same service level.

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EJIPT E 0220

8. Train "B" It consists of Safety-Related System redundant power load group "B" and Supplies Class 1 Diesel Generator backed power to Channels "B" and "D". Train "B" and Channel "B" circuits share common raceways of the same service level.

C. Channel "A" It consists of Class 1 instrumentation, control and power cable, raceway. and equipment required for DC Subsystem "A" and vital AC instrumentation and Control Channel "A". Train "A" and Channel "A" circuits share common raceways of the same service levels.

D. Channel "B" It consists of Class 1 instrumentation, control and power cable, raceway and equipment required for DC Subsystem "B" and vital AC instrumentation and Control Channel "B". Train "B" and Channel "B" circuits share common raceways of the same service levels.

E. Channel "C" It consists of Class 1 instrumentation, control and power cable, raceway and equipment required for vital AC instrumentation and Control Channel "C" or DC Subsystem "C".

I F. Channel "D" It consists of Class 1 instrumentation, control and power

' cable, raceway and equipment required for vital AC instrumentation and Control Channel "D" or DC Subsystem "D",

9. Class 2 Group: The Class 2 group includes all non-safety related (Non-Class 1) equipment, devices, cables, wires, and raceways.

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ERPI 8 02%0 l IV. EQUIPMENT SEPARATION

1. Diesel Generator Building The separation of redundant equipment in the Diesel Generator Building meets the requirements of Regulatory Guide 1.75 as described below:

The Train "A" TDI diesel generator and its auxiliaries are located in the west half of the Diesel Generator Building, separated by a 3-hour fire wall from the Train "B" TDI diesel generator and its auxiliaries. Figure 1 indicates the locations. The Train "A" equipment is cooled by the Train "A" ventilating system, and the Train "B" equipment is cooled by the Train "B" ventilating system.

2. NSEB The separation of redundant equipment in the NSEB meets the requirements of Regulatory Guide 1.75 as described below:

The Train "A" 4160 volt switchgear, 480 volt switchgear, and 480 volt MCC are located in a separate room from the Train "B" gear.

Figure 1 indicates the locations. The walls and penetrations are 3-hour rated. A separate Class 1, HVAC system is provided for each. The HVAC systems are redundant and independent.

The Class 1 battery for each of Channels "A", "B", "C", and "D" is l located in a separate room. Each room has a Class 1 exhaust fan. t The "A" and "C" batteries are served by the Class 1, Train "A" HVAC system. The "B" and "D" batteries are served by the Class 1, Train l "B" HVAC system.

The Channel "A" and "C" battery chargers, distribution panels, and inverters are located in the room containing the Train "A" I

switchgear and MCC. The Channel "B" and "D" battery chargers, distribution panels, and inverters are located in the room containing the Train "B" switchgear and MCC. Battery chargers, inverters, and distribution panels for redundant channels are at least ten feet apart, and at least three feet below the closest tray, thus meeting the Regulatory Guide 1.75 requirements. Figure 1 indicates the locations.

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ERPT E os2q V. RACEWAY SEPARATION

1. Separation Between Class 1 and Class 2 Raceways in NSEB and D/G Building A. Class 2 enclosed raceway to Class 1 raceway (tray or conduit):

1) A minimum of 1" separation is maintained between Class 1 raceways (trays and conduits) and Class 2 enclosed raceways used for power and control circuits, to meet the requirements of Regulatory Guide 1.75. (see Appendix A, Section 3 for justification)

2) In a limited number of cases, Class 1 raceways and Class 2 conduits used for instrumentation circuits are allowed to touch each other. The instrumentation circuits use shielded cables qualified per IEEE 383, carry low energy signals and are routed in instrumentation raceways (see Appendix A, Section 3 for justification).

B. Class 2 tray to Class 1 raceway:

1) Class 2 trays are separated from Class 1 raceways by a  !

minimum of 3 f t. horizontal or 5 ft. vertical distance to meet the requirements of Regulatory Guide 1.75.

2) Where above distances are not met, then one of the following measures is used:

(a) Separation barriers are installed per Figure 2, or (b) Tray covers are installed per Figure 2, or (c) Class 1 rigid conduits are wrapped with 200 percent overlap (3 layers) of Siltemp 188 CH (see Appendix A, .

Section 7.B for justification),

2. Separation Between Redundant Class 1 Raceways in NSEB and D/G )

Buildings A. Tray to tray separation - Trays of redundant Class 1 systems are installed in separate rooms with 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> fire walls to meet the requirements of Regulatory Guide 1.75.

8. Tray to enclosed raceway separation - One of the following approaches is used:

1) To meet the Separation requirements of Regulatory Guide 1.75, Class 1 trays of Train / Channel "A" are separated-from redundant enclosed raceways of Train / Channel "B" by a minimum of 3 ft. horizontal and 5 ft. vertical distance and vice versa.

2) Separation barriers are installed per Figure 2 to meet the separation requirements of Regulatory Guide 1.75.

3) Tray covers are installed per Figure 2 to meet the separation requirements of Regulatory Guide 1.75.

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ERPI E 0220 )

4) In a limited number of cases for channel separation within )

a train, Class 1 trays of Train / Channel "A" (B), when used for 480V or lower voltage circuits with cables sized #2/0 AWG or smaller, are separated from rigid conduits (carrying 480V or lower voltage circuits with cables sized 500 MCM or smaller) of Channel "C" (D) by a minimum distance of 3  !

inches (see Appendix A, Section 7. A for justification).

5) In a limited number of cases for channel separation within a train, trays and cables at least one inch apart from the redundant channel enclosed raceway, when used for 480V or lower voltage circuits with cables sized #2/0 AWG or smaller, are wrapped with 200 percent overlap (3 layers) of Siltemp 188 CH if the separation requirements of Paragraph V.2.B.4 are not maintained (see Appendix A, Section 7.B for justification).

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6) In a limited number of cases for channel separation within a train, conduit at least one inch apart from the redundant ,

channel trays or cables, when used for 480V or lower l voltage, are wrapped with 200 percent overlap (3 layers) of J l Siltemp 188 CH if the separation requirements, of Paragraph V.2.B.4 are not maintained (see Appendix A, Section 7.B for i justification). l i

7) In four special cases, a 16 inch electrical pipe duct is {

, used between the NSEB and Auxiliary Building. Two of these 9 ducts are used for Train / Channel "B" circuits and a 4 inch flexible conduit carrying Channel "D" circuits runs through 'j each of these 16 inch ducts. The other two ducts are used for Train / Channel "A" circuits and a 4 inch flexible conduit carrying Channel "C" circuits runs through each of )

these two 16 inch ducts. Two of these ducts (one for l Train / Channel "A" and second for Train / Channel "B") with I their associated flexible conduits, are used for I l instrumentation circuits only and the other two ducts with their associated flexible conduits are used for 480V power and control circuits (see Appendix A, Section 7.D for justification).

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8) In a few isolated cases for channel separation within a I train, where the separation requirements of the above Paragraph V.2.B.4 are met but larger than no. 2/0 AWG cables (no. 2/0 AWG is the maximum size allowed per Paragraph V.2.B.4) are routed through the trays. These circuits, under worst conditions of loading, will not be overloaded to such an extent that the cable insulation will ignite (see Appendix A, Section 7.E for justification).

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1 ERPT E O220 l l

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l C. Enclosed raceway to enclosed raceway separation - At least one inch separation is maintained between enclosed raceways of redundant trains / channels, except in one case a rigid conduit with Channel "D" instrumentation circuits is allowed to touch a flexible conduit with Train / Channel "B" instrumentation circuits (see Appendix A, Section 7.C for justification). '

VI. INTERNAL SEPARATION

1. Wiring Separation Within Enclosures in NSEB and D/G Buildings:

One of the followin approaches is used to meet the requirements of Regulatory Guide 1. 5 l

A. A minimum of six inch separation is maintained between j redundant channel wiring and between Class 1 and Class 2 wiring, i B. A barrier is installed to separate wiring of the redundant trains / channels from each other and from the Class 2 wiring.

C. The control and instrumentation wiring (No. 8 AWG or smaller) ,

of one of the redundant channels or Class 2 is enclosed with I 100 percent overlap (2 layers) of Siltemp 188 CH (tape or sleeving) and then wrapped with 3M Scotch 69 glass cloth tape.

The unwrapped wiring of the other redundant channel belonging to the same train (A to C or B to D) or Class 2 group is allowed to touch the wrap. The wrapping provides a barrier between separated cables when the 6 inch minimum separation distance is not maintained (see Appendix A, Section 8.8 for justification).

D. The control and instrumentation cables (No.10 AWG or smaller) of two redundant channels belonging to the same train (A to C or B to D) or Class 1 and Class 2 circuits where six inch separation cannot be maintained, are protected by installing copper braid over each conductor insulation and an additional braid over the cable jacket from the cable breakout. Then the braids are covered with fire retardant insulating tubing and the braid is grounded (See Appendix A, Section 8.C for Justification). )

1 E. In the following three types of applications at six equipment locations where the location of terminations is such that the ]

above separation requirements are very difficult to meet, the lack of separation is shown to be acceptable because the level i of energy available in each circuit is sufficiently low to i preclude the possibility of degrading the adjacent circuits.

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1) In Class 14.16 kV switchgear S4A2 and S4B2, Class 2 output j signal (4-20mA) wiring downstream of four isolating i transducers in each switchgear is touching the Class 1  !

wiring (see Appendix A, Section 8. A.1 for justification ). I REDRPT(C) 8

ERPI E 0220

2) In TDI D/G control panels H2DGA2 and H2DGB2, Class 2 output signal (+1mA) wiring downstream of five isolating transducers in each panel is touching the Class 1 wiring (see Appendix A, Section 8. A.2 for justification).

3) In multiplexer cabinets H4CDAR7 and H4CDAR9, cables carrying a number of signals for SPDS from Channels "A" (B) and "C" (D) devices are allowed to touch each other and the Class 2 output cables (see Appendix A, Section 8.A.3 for justification).

VII. RACEWAY / CIRCUIT IDENTIFICATION

1. Class 2 (non-safety related) raceways are identified as follows:

A) A number as the first character, followed by numbers and )

letters in the identification of raceway indicates that it is a power and control tray (e.g. , 740AE1, 740AD1, 743M1, etc. ).

B) A number followed only by numbers identifies power and control ,

conduits (e.g., 735740, 739116, 747177 etc. ).

C) The letter "X" followed by numbers and letters in the )

identification of a raceway indicates that it is an instrumentation tray (e.g. , X41BF3, X41CB3, X43V22 etc. ), and the first alpha character "X" followed only by numbers identifies an instrumentation conduit (e.g. , X35304, X42017, X41060, etc. ).

D) The letter "T" followed by numbers identifies a communications conduit.

2. Class 1 (safety related) raceways are identified as follows:

A) The letter A, B, C, D, L, M, P, or W as the first character in the raceway is safety related.

, B) The first letter L or M, followed by numbers and letters, ,

identifies a power and control tray (e.g. , L39L5, M35AJ1), and- 1 i the first letter L, M, P, or W followed only by numbers j l identifies a power or control conduit (e.g. , L35134, M36104, I W41211, and P41158, etc. ).

C) The first letter A or B followed by numbers and letters identifies an instrumentation tray (e.g. , A28V6, A32V2, etc.).

D) The first letter A, B, C, or D followed only by numbers identifies an instrumentation conduit (e.g., A41221, B39411, C39412, D41215, etc. ).

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ERPI E 0220 i

E) The "A" or "L" designation is used for Train / Channel A conduits or trays, "B" or "M" is for Train / Channel B conduits or trays, "C" or "P" for Channel C conduits, and "D" or "W" is for j Channel D conduits.

3. The second and third characters in tne raceway number identify the drawing on which the raceway appears. For example L39L5 appears on Drawing E-739, and 740AE1 appears on Drawing E-740.

4. Raceways and circuits are assigned the color of the related separation group and marked as follows to comply with the 4 requirements of Regulatory Guide 1.75:  ;

A) Trays are identified on the electrical layout drawings by unique identifying numbers. This number is permanently fixed to the tray at each end on both side rails (where both are i visible), at all tray to tray junctions, and on each side of )

every wall the tray penetrates (see Appendix A, Section 6. A for j I

justification).

B) Conduits are identified by affixing permanent markers to the conduits at the beginning and the end of run and where conduit )

passes through walls or floors, both sides (see Appendix A, i Section 6.B for justification).

C) Cable raceways are identified by color coded markers. Trays or conduits used for Class 1 channels have diamond shaped color spots corresponding to the channel color code. For example, a Train / Channel A tray is identified with red tray marker .

l D) The jackets of all external cables in Class 1 raceway have a stripe of the color corresponding to the protection channel they serve.

l Train / Channel-colored circuits are installed in raceways that are labeled with a color identical to that on the cables or i

wires. The following color scheme has been used for i identification of circuits and raceways, '

Trair./ Channel A - Red Train / Channel B - Yellow Channel C - Blue Channel D - Brown In addition to the above color identification of cables, every cable is identified at termination points by affix:u markers.

Markers have the cable number plus a color mark corresponding to the train / channel color. Class 2 (Non-safety related) cable markers have no color mark.

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ERPI E 024V VIII. REFERENCES

1. SMUD Letter No. JEW 86-152 to USNRC, dated October 2,1986.

2. SMUD Letter No. JEW 87-358 to USNRC, dated April 1,1987.

3. US Nuclear Regulatory Commission, Regulatory Guide 1.75, Revision 2.

4. IEEE Standard 384-1974, IEEE Trial-use Standard Criteria for Separation of Class lE Equipment and Circuits.

5. Rancho Seco NGS, Updated Safety Analysis Report, Chapter 8, Section

8. 2.2.11, Amendment No. 4,

6. Wyle Laboratory's Test Report No. 48141-02, Volumes 1 and 2, submitted to NRC with a proposed change to the Vogtle FSAR /

(Amendment 25), on July 13, 1986. NRC Docket Numbers 50-424 and 50-425.

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ERPT E 0220 APPENDIX A CLARIFICATIONS / INTERPRETATIONS OF REGULATORY GUIDE 1.75 Clarification / interpretations of IEEE 384-1974 (as endorsed by Regulatory Guide 1.75, Revision 2) for NSEB and D/G Building of Rancho Seco are as follows:

1. Section 4.5, Associated Circuits: The associated circuits as addressed in this section are not uniquely identified as such. Class 2 circuits associated with a Class 1 train / channel are treated as Class 1 up to and including isolation devices and are treated as Class 2 after the isolation devices. The circuits are treated as Class 1 or Class 2 as explained below:

A. Class 2 instrument circuits from isolation transducers in Class 1 switchgear and the TDI D/G panels run in close proximity to Class 1 circuits in the enclosure.

Justification: These circuits use shielded instrumentation cables qualified per IEEE 383, carry low energy signals (maximum of 20mA),

and are routed in dedicated instrumentation raceways. These cables cannot damage Class 1 circuits even when these are in close proximity, since these circuits are protected with grounded shield cables throughout their route through Class 2 raceways and are inherently low l energy circuits (see Section 8A for further clarification). l l

B. Functionally Class 2 circuits such as those for indicating lights in l Class 1 schemes are treated as Class 1 in all respects. l Justification: There is no increased exposure to failure of other Class 1 cables due to lack of physical separation between these I functionally Class 2 circuits and Class 1 circuits.

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2. Section 4.5(3) Analyses: The intent of Regulatory Guide 1.75 is met by making analysis per this section and recording the analysis in the form of calculations / reports that are part of the plant records.

Justification: The Regulatory Guide 1.75 requirements for such analysis to be submitted as part of the safety analysis report appears to apply to plants that are still under construction. Making all the analyses a part of the plant records will ensure that these are properly documented.  ;

3. Section 4.6.1 Separation of Class 2 from Class 1 Circuits: The intent of Regulatory Guide 1.75 is met by maintaining at least the same separation of Class 1 circuits from Class 2 power and control circuits as that maintained between redundant Class 1 circuits, as specified in the discussion of Section 5.1.4, except enclosed raceway to enclosed raceway separation distances are used when the Class 2 circuits are routed through A-1

ERPT E 0220 enclosed raceways and the Class 1 circuits are routed through open trays {

or enclosed raceways.

Justification: The redundant circuit separation listed in Section 7 of A this Appendix (covering IEEE 384 Section 5.1.4) is sufficient to ensure /I \

that a fault in a Class 1 power or control circuit cannot disable redundant circuits. The same degree cf separation will be sufficient to ensure that faults in Class 2 power and control circuits cannot disable the adjacent Class 1 circuits, since the same type of flame retardant i cable is used for both Class 1 and Class 2 cables. Tests in Reference 6 have demonstrated that one half inch [l/2"] clear air space between enclosed raceway [ Class 2] containing faulted circuits and target circuits in open air [ Class 1] is adequate to prevent damage to the target ci rcuits. Rancho Seco maintains one inch [1"] clear space or more. A Conversely, damage from faulted Class 1 circuits [in open air] to Class 2 Q2 circuits in enclosed raceway is acceptable because the Class 2 circuits have no safety function.

Additionally, raceways for Class 2 instrumentation circuits connected to transducers, RTD's and thermocouple; and Class 2 instrumentation circuits running from a multiplexer to a dedicated computer input contact are allowed to touch raceways for Class 1 circuits, without creating associated circuits.

Justification: Class 2 instrument raceways touching Class 1 raceways have circuits that carry only mil 11 ampere current even under faulted conditions. Therefore, the Class 2 instrumentation raceways are allowed to contact Class 1 raceways, since no credible faults can cause the Class 2 cables to overheat.

4 Section 5.1.1.3, Flame Retardant Cables and Raceways: All the cables in open raceways have been qualified by test to meet the requirements of IEEE 383 vertical tray flame test. Lighting and communication cables are routed only in conduits (rigid, flex and EMT) as these cables do not meet the IEEE 383 vertical tray flame test. '

5. Section 5.1.1.3, Cable S)11ces: The prohibition of cable splices in )

raceways is implemented )y prohibiting cable splicing in conduits, trays and underground ducts, and allowing cable splicing only in equipment enclosures, junction boxes and condulets when it is impractical to use terminal blocks.

Justification: Splices of equipment pigtails or other wiring in equipment enclosures, junction boxes and condulets are controlled by the drawings and procedures, and are a standard type of termination. Since these splices are not in conduits or cable trays, no individual justification is y required. I i

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6. Section 5.1.2, Identification: The intent of the requirement to mark I exposed Class 1 raceways in a distinct permanent manner at intervals not to exceed 15 feet and at points of entry to and exiting from enclosed areas, is met as follows:

A. Trays are identified on the electrical layout drawings by unique identifying numbers. Color coded markers with the tray numbers are permanently fixed to the trays at each end on both side rails (where l both are visible), at all tray to tray junctions, and on each side of I every wall the trays penetrate.

Justification: Tray runs, in general, are less than 15 feet long, j Thus marking trays on both sides, at all tray to tray junctions and on each side of every wall the trays penetrate, meets the intent of Regulatory Guide 1.75.

B. Conduits are identified by affixing permanent color coded markers with the conduit numbers to the conduits at the beginning and the end of j run and where conduit passes through walls or floors, both sides. )

Justification: Marking the conduit runs at the beginning and the end, l and on both sides where conduits pass through walls or floors,

, provides adequate identification of the conduits and meets the intent l of Regulatory Guide 1.75.

7. Section 5.1.4, Raceway Separation in General Plant Areas:

The raceway separation requirements of this section are met in all areas of NSEB and D/G Building, except in the following cases involving separation between Channels "A" and "C" and between Channels "B" and "D":

l A. In certain cases for separation between channels of a train, Class 1 rigid conduits are separated from Class 1 redundant channel raceways ,

by at least 3 inches but less than the minimum requirements of I l Regulatory Guide 1.75. The potential fault cables in these raceways i are limited to operate at 480V or less and are of sizes #2/0 AWG or smaller in open trays and 500 MCM or smaller in rigid conduits.

l Justification: A separation distance of one inch was accepted at a recently licensed nuclear power generating station, based upon tests for a similar configuration. (See Reference 6). All Class 1 power and control cables at Rancho Seco are qualified by test to meet the k requirements of IEEE 383 vertical tray flame test. However, a separation distance three times as great as the distance shown to be .

safe in those tests is being used at Rancho Seco to account for any j differences between insulation / jacketing material of the cables tested and the cables installed at Rancho Seco (see Appendix B, Section 2. A for further details). l 1

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ERPT E 0220 B. In isolated cases, where the separation between a channel enclosed raceways and redundant channel open trays belonging to the same train.

when used for 480V or lower _ voltage circuits is between one inch and three inches, one of the redundant channel raceways is wrapped in three layers (200% overlap) of silicon dioxide cloth (Siltemp 188 CH).

Justification: Tests for similar configurations were performed for another plant to show that faulted armored cables when wrapped with two layers (100 percent overlap) of siltemp 188 CH did not damage cables separated by one inch. (See Reference 6). In addition, the l/

tests showed that an open air faulted cable (non-annored) did not damage cables separated by one inch and wrapped with two layers (100 percent overlap) of Siltemp 188 CH. The approach of wrapping rigid conduit with three layers (200 percent overlap) of Siltemp 188 CH for Rancho Seco provides additional conservatism for differences in the type of insulation / jacketing materials between the tests' and actual .

installation (see Appendix B, Section 2.8 for~ further details).

C. In one case, a rigid instrument conduit with Channel "D" instrument circuits is allowed to touch a flexible liquid tight conduit with Channel "B" instrument circuits (both channels belonging to Train "B").

Justification: Both the conduits have circuits that carry only mil 11 ampere current even under faulted conditions. Therefore, the instrument conduits are allowed to touch since no credible faults can cause the instrument cables to overheat and damage cables in another conduit.

D. Four 16 inch electrical pipe ducts are used between the NSEB and l Auxiliary Building. Two of these ducts are used for Channel "B" circuits and a four inch flexible conduit carrying Channel "D" circuits runs through each of these 16 inch ducts. The other two ducts are used for Channel "A" circuits and a four inch flexible conduit carrying Channel "C" circuits runs through these two 16 inch ducts. Two of these ducts (one for Train / Channel "A" and second for Train / Channel "I") w1M their associated flexible conduits are used for instrumentation circuits only and other two ducts are used for 480V power and control circuits.

Justification for Instrumentation Ducts: Instrumentation circuits in two 16-inch duct and their associated flexible conduits carry only mil 11 ampere current even under faulted conditions. Thus no credible i faults can cause the instrumentation cables to overheat and damage the redundant channel cables separated by a flexible conduit. Therefore, 1 the instrumentation circuits in the duct are allowed to touch the flexible conduit carrying instrumentation circuits of the redundant channel belonging to the same train.

l A-4 4

EP.PT E O240 Justification for Power and Control Ducts: A flexible conduit inside each of the two power and control pipe ducts (one flexible conduit for Channel "C" inside of duct for "A" and the second for Channel "D" inside of duct for "B") carry only one power and two control circuits for an Auxiliary Feedwater isolation valve (HV20581 of Channel "C" and HV20582 of Channel "D"). Therefore, if any of the circuits in a duct (Train / Channel A or B) fails and damages the circuits in the flexible conduit by close proximity, only one of the auxiliary feedwater isolation valves will be disabled. There are two parallel paths for Auxiliary Feedwater supply to each steam generators. So due to failure of one auxiliary feedwater isolation valve, only one of the two parallel paths to a steam generator will be disabled and the second path can supply auxiliary feedwater to the steam generator.

Moreover, if the disabled valve fails in the open position, a control valve in series with this valve can provide the required auxiliary feedwater flow. On the other hand, the protection of these circuits is such that these circuits will not overheat to ignite the cable insulation even if the primary protection fails under faulted conditions. Therefore, these circuits inside the flexible conduits will not damage circuits that are inside the duct and touching the l flexible conduit.

Thus it is concluded that if the circuits in the flexible conduits for l Channels "C" or "D" are damaged, the plant can still shut down safely q under Design Basis Events. Also these circuits have energy low enough not to damage Train / Channel "A" or "B" circuits in the ducts.

E. In a few cases for channel separation within a train, where the separation between the rigid conduits of a channel is at least three '

inches from the open trays of a redundant channel, cables of 250 MCM and 350 MCM for 480V and lower voltages are routed through these trays. '

Justification: The separation of an open Class 1 tray from a redundant channel's rigid conduit by at least three inches for 480V or lower voltage circuits with cables sized #2/0 AWG and smaller in the open tray is justified in section 7.A of Appendix A. A few 120VAC uninterruptible power supply circuits for connecting the inverter and the regulating transformer to the bypass switch, the transfer switch  !

and the distribution panel, by using either 1/c-350MCM per leg or i 2-1/c 250MCM per leg are routed through the open trays. These circuits are protected by the current limiting characteristics of the inverter (150% of full load for 10 seconds and then 125% thereafter) or the voltage regulating transformer (175% of full load). By i calculating the cable temperature rise, it is concluded that these cables, even under worst loading, will not get hot enough to ignite the cable insulation and thus pose no threat to the circuits in a- I nearby conduit.

A-5 l

l 1

J

l ERPT E 0220 Another similar application is the main feed (2-1/c 350 MCM per phase) i to an MCC from a 480V switchgear. The circuits are protected by 480AT I breaker and 1000 A fuse. By calculating the temperature rise, it was I concluded that 2-1/c 350 MCM can carry 1000 A without overheating the cable to such an extent as to ignite the cable insulation. Thus these circuits pose no threat to the circuits in nearby conduits.

8. Section 5.6.2, Separation Inside Equipment

Enclosures:

The intent of internal separation requirements of this section is met by providing six inch separation between the two separation groups, providing metal barriers, or use of one of the following approaches in a limited number of cases:

A. In three types of applications at six equipment locations, wiring of two channels belonging to a train or Class 1 and Class 2, carrying low energy signal, is allowed to touch each other as described below:

1) In 4.16 kV switchgear S4A2 and S4B2, Class 2 output (4-20mA) wiring of four isolating transducers in each switchgear is allowed to touch Class 1 wiring.

Justification: The shielded instrumentation cables carrying the transducer output, are run in dedicated instrument raceways. The transducer output wiring carries only mil 11 ampere current even under faulted conditions. Therefore, the Class 2 wiring cannot get overheated and damage the adjoining Class 1 wiring.

2) In TDI diesel generator control panels H2DGA2 and H2DGB2, Class 2 output (+1mA.) wiring of five isolating transducers in each panel is allowed to touch Class 1 wiring and terminate on terminals adjacent to Class 1 terminals.

Justification: The shielded instrumentation cables carrying the transducer output, are run in dedicated instrument raceways. The transducer output wiring carries only milliampere current even under faulted conditions. Therefore, the Class 2 wiring cannot get overheated under any credible fault conditions and damage the -

adjacent Class 1 wiring.

3) In multiplexer cabinets H4CDAR7 and H4CDAR9, a number of cables carrying signals for SPDS from Channels "A" (B) and "C" (D) devices are not separated from each other and from Class 2 outputs.

Justification: An analysis was performed to show that all the cables are low energy circuits and cannot damage each other. This analysis is documented in the form of a calculation'(Calculation No. Z-SEP-E0693) and is part of the permanent project records. j l

i A-6 j l

1 1

l l

1 ERPT E 0220 B. The control and instrumentation wiring (no 8 AWG or smaller) of one of the redundant channels or Class 2 wiring is enclosed with 100 percent ,

overlap (two layers) of Siltemp 188 CH (tape or sleeving) and then 1 wrapped with 3M Scotch 69 tape. No separation is provided between the i wrap and wiring of other channel belonging to the same train or Class l 2 group.

Justification: Tests for similar configurations were performed for another plant to show that two control type cables No. 8 AWG or smaller can be mounted in contact with each other, with either cable wrapped inside a 100 percent overlap (two layers) of Siltemp 188 CH material, when the worst case electrical fault occurs in either cable. (See Reference 6). For Rancho Seco, one of the separation j group cables is wrapped with a 100 percent overlap (two layers) of siltemp (tape or sleeving) plus an outer wrap of 3M Scotch 69 (glass cloth) tape. The outer wrap of 3M Scotch 69 tape provides additional protective margin to allow for differences between the insulation / jacketing material of the cables tested and the actual cables used for Rancho Seco (sne Appendix B, Section 2.C for further detail s) .

C. The control and instrumentation cables (No.10 AWG or smaller) of- two redundant channels belonging to the same train or Class 1 and Class 2 circuits are protected by installing copper braid over each conductor insulation and an additional copper braid over the cable jacket from cable breakout up to the point where at least six inch separation is maintained. The flame retardant insulating tubing (color coded per channel) is installed over the braid of individua conductors and Raychem WCSF-N shrink tubing is installed over the braid on the cable jackets. All the braids for a cable touch each other and are grounded at one end.

Justification: All the cables to be separated are control or instrument type and are carrying only small amounts of energy. The braid covered with flame retardant insulating sleeving provides additional protection and prevents contact with other live conductors. If for any reason the conductor overheats, it would short to the grounded braid, tripping the power source before the shrinkable tubing will burn and damage the " target" cable, which is also covered with braid and outer flame retardant insulating tubing.

A-7

ERPT E 0220 APPENDIX B ANALYSIS OF REGULATORY GUIDE 1.75 SEPARATION REQUIREMENTS BASED ON THE TESTS FOR ANOTHER PLANT

1. TESTS Tests for configurations similar to those used for Rancho Seco have been performed for another plant. (See Reference 6) The selection of /

overcurrent conditions, test configurations, test initial conditions, and tests were based on the following:

A. Overcurrent Condition: All test currents were selected by assuming failure of a circuit's primary overcurrent protection, and are thus at current levels just below the pickup setting of the circuit's secondary overcurrent protection plus 10 percent. Test currents were i conservative.ly maintained at a constant value as the circuit impedance l increased due to conductor temperature rise. ,

B. Configurations: Test configurations were conservatively developed based on actual cable and raceway installations.

C. Test Initial Conditions: Actual cable operating conditions were established prior to each fault current test by energizing the fault cable and several adjacent cables.

D. Cables: All power and control test cables had EPR insulation and Hypalon jacket; instrumentation' test cables had XLP0 insulation and Hypalon jacket; and SIS switchboard wiring was used for testing separation inside the panels.

E. Screening Tests: Screening tests were performed to determine the cable which, if faulted, would have the most impact on adjacent cables. The worst case cables selected from these tests were used as the faulted cables for other testing.  !

(

2. COMPARISON The following are the various test configurations and their applicability to the actual Rancho Seco installations:

A. Two previous successful test configurations are used as the basis for establishing three inch separation of Class 1 rigid conduit from the f redundant raceways when circuits in these raceways are limited to 480V j or less and a maximum size of #2/0 AWG in open trays and 500 MCM in j the rigid conduits. '

B-1 j

O220 ERPT E l

l l The analysis is described as below:

1) A test (Test A) was performed by using 3/C 500 MCM armored fault cable mounted 3/4 inch vertically below the tray containing the target cables.

The target cables were undamaged when a test current of 2600A was impressed on the fault cable and continued until the faulted cable open circuited. Test A is Configuration No. 2, Test No. 5 in Reference 6.

l Another test (Test B) was performed between 3-1/C #2/0 AWG fault cables in free air and a cable inside flexible conduit mounted one inch vertically above the fault cable. The cable in the flexible conduit was undamaged when a test current of 2600A was impressed on the fault cable and i continued until the faulted cable open circuited. Test B is Configuration 3, Test No. 1 in Reference 6,

2) The following is the comparison of the tests with Rancho Seco's design:

ITEM TEST RANCHO SEC0 Fault cable in en- 3/C 500 MCM armored cable 1/C 500 MCM and smaller closed raceway in without additional enclo- in rigid conduit. Rigid  ;

Test A. sure. conduit provides greater i protection than armor.

Physical separa- Tray with target cables Tray is three inches away tion of target was vertically 3/4 from rigid conduit.

cables from fault inch above the fault cable in Test A. cable.

Fault cables in 3-1/C #2/0 AWG in free #2/0 AWG and smaller in Test B. air, trays.

Physical separa- Flexible conduit carry- Rigid conduit with tar-tion of target ing target cable was get cables is three cable from fault one inch vertically inches apart form the cables in Test B. above the fault cables. tray carrying fault cable. Rigid conduit  !

provides better protec-tion than flexible conduit.

Insul ation/j acket- EPR/Hypalon and meets Different combination of ing material of the requirements of insulations (EPR, XLPE) fault cables in IEEE 383 vertical tray and jacket (HYPA, NEOP, both tests. flame test. ASBE) but all meet the requirements of IEEE 383 vertical tray flame test.

B-2 l

L-__________-_________-_-_________________________________

ERPI E 0220 1

Maximum fault 2600A All circuits are pro-current in both tected by a secondary tests. backup protection of 2000A (maximum) except for a few circuits that are analyzed to show less j severe impact on the tar-get cables. {

i

3) From the above comparison it is concluded that the rigid conduit in the Rancho Seco configuration provides a substantially greater barrier between the fault cables and the target cables than that in the test configuration. In addition, the fault current of the Rancho Seco circuits is lower than the test current. However, a separation distance at least three times.as great as the distance shown to be safe in the tests is being used at Rancho Seco. This increased separation provides increased conservatism to account for differences between the insulation and jacketing material ~of-the cables tested, and the cables installed at Rancho Seco.

B. One previous test with wrapped target cables and Tests A and B from above Section 2.A.1 of this appendix are used as the basis for wrapping one of the redundant raceway groups when separation of Class 1 rigid conduit from the redundant raceways is within 1 to 3 inches.

The circuits in these raceways when wrapping conduit, are limited to a maximum size of 500 MCM at 480V or lower. If the open tray or cables 1 are wrapped, the circuits in the open raceway are limited to a maximum ,

of No. 2/0 AWG at 480 V or lower If the open tray or cables are wrapped, the circuits in the open raceway are limited to a maximum of No. 2/0 AWG at 480V or lower voltage..

The analysis is described as below:

1) A test (Test C) was performed between 3-1/C 500 MCM fault cables in free air and a number of target cables wrapped with Siltemp at a distance of.one inch vertically above the fault cable. T'1e target cables were undamaged when a fault current of 2600A was impressed on the fault cables and continued until the faulted cable open circuited. Test C is Configuration 4, Test 2 in ,

Reference 6.

2) The following is the comparison of the _ tests with the Rancho Seco design:

ITEM TEST RANCHO SECO Fault cable in Test 3/C 500 MCM amored cable 1/C 500 MCM and smaller .

A (Section 2. A.1 without additional in rigid conduit. Rigid of this appendix). enclosure. conduit provides greater protection than armor.

B-3

1

'ERPT B U2d0 Physical separa- Tray with target cables Tray is at least one inch tion of target was vertically 3/4 inch away from the rigid cables from fault above the fault cable. conduit. In addition, cable in Test A either the tray or (Section 2. A.1 of conduit with faulted the appendix) cable is wrapped with I 200 percent overlap (3 layers) of Siltemp 188 CH.

Fault cables in 3-1/c #2/0 AWG in free #2/0 AWG and smaller in test B (Section air. trays.

2-A-1 of this appendix).  !

Physical separation Flexible conduit carry- Rigid conduit with target ,

of target cable ing target cable was cables is at least one from fault cables in one inch vertically inch apart from the tray, test B. above the fault cables. In addition, either the tray with faulted cable  ;

or the conduit with  ;

target cables-is wrapped _

with 200 percent overlap 1 (3 layers) of Siltemp 188 CH.

! Fault cable in Test 3-1/c 500 MCM cables in 1/C 500 MCM and smaller 1 C. free air in trays.

l Physical separa- Target cable wrapped Cable tray with target I tion of target with Siltemp 188 CH cables is at least one ,

cable from fault (100 percent overlap) inch apart from the '

cables in Test C. material and maintained - rigid conduit carrying one inch vertically the faulted cable and above the fault cables, one of the redundant I raceways is wrapped with l Siltemp 188 CH (200 percent overlap).

material .

1 Insulation /j acket- EPR/Hypalon and meets Different combination of I ing material of the requirements of insulation (EPR, XLPE) fault cables in IEEE 383 vertical tray and jacket (HYPA, NEOP, both tests. flame test. ASBE) but all cables meet the requirements  :

of IEEE 383 vertical tray flame test.

B-4 l

\ -- - ___

ERN E v22O Maximum fault 2600A All circuits are pro-current in both tected by a secondary  ;

tests, backup protection of ,

2000A (maximum) except I a few circuits that are  !

analyzed to show less severe impact on the target cables.

3) From the above comparison it is concluded that the rigid conduit-in the Rancho Seco configuration provides' a substantially greater '

barrier between the fault cables and the target cables than that 1 in the test configuration. In addition, the fault current of the Rancho Seco circuits is lower than the test current. However, an additional layer of Siltemp 188 CH is used to wrap the conduits at Rancho Seco. This third layer provides increased conservatism to account for differences between the insulation and jacketing material of the cables tested, and the cables installed at Rancho Seco.

C. Two previous successful test configurations are used as the basis for wrapping wiring of one of the redundant channels or Class 2 wiring and allowing the wiring of the other channel to touch the wrap inside equipment enclosures. The analysis is described as below: ,

1

1) A test (Test D) was performed between a 1/C #8 AWG free air fault cable and target cables wrapped with Siltemp. The fault cable was allowed to touch the outside wrap of the target cables. The ,

target cables were undamaged when 566A test current was impressed l on the fault cable. Test D is Configuration 6, Test No.1 in l Reference 6.

Another test (Test E) was performed by wrapping 1/C #8 AWG. fault cable and allowing the free air target cables to touch the l wrapping. The target cables were undamaged when 566A test current i was impressed on the faulted cable. Test E is Configuration 6, Test No. 2 in Reference 6.

2) The following is the comparison of the tests with Rancho Seco's design ITEM TEST RANCHO SEC0 Fault cable in Test 1/C #8 AWG SIS in free #8 AWG and smaller in D. air and meets ICEA free air inside en-flame test requirements. closures. These cables meet ICEA flame test requirements.

Physical separation Target cables were wrap- Target cables are wrap-of target cables ped with 100 percent ped with 100 percent from fault cable overlap of Siltemp 188 overlap (two layers) of in Test D. CH and allowed to Siltemp 188 CH or equiv-touch fault cable. alent sleeving. In addition, an outer wrap i of 3M Scotch 69 tape is used for additional protection.

B-5

spy e 0220 Fault cable in Test 1/C #8 AWG SIS wire was #8 AWG and smaller in E. wrapped with 100 percent free air. Either fault overlap of Siltemp 188 or target cable is wrap-CH. ped with 100 percent overlap (two layers) of Siltemp 188 CH. In addition, an outer wrap a

of 3M Scotch 69 tape is used for greater protection.

Physical Separa- Target cables are al- Target cables are al-tion of target lowed to touch the Sil- lowed to touch the outer '

cables from fault temp wrap on the fault wrap of 3M Scotch 69 on cable in Test E. cable. the top of Siltemp wrap.

that contains the fault cable.

Maximum fault 566A 300A or less.

current in both tests.

3) From the above comparison, it is concluded that the configuration for Rancho Seco is comparable to the test configuration. In j addition, the fault current of Rancho Seco circuits is less than '

the test current. The outer wrap of 3M Scotch 69 tape provides additional protective margin for any difference in wiring insulation.

l i

j B-6

I ERPT E 0 2 20 l

'B'/'D' 16' D. ELECT. PIPE DUCTS AT 37'-0' g 'B' MCC l r 1 Y _ l l l V r- - '

'B' -

'o 1- 'D' l

_ .t BATTERY c' i 'B' SWCR. i,w5 BATTERY c)

Z S!

w !b i-i

.B. '-~

O 'B' LD. CTR.

g ___________ C BLE SHAFT _.I  !

D 'B' TUNNEL i i i i CLASS 2 CORRIDOR _

g 'A' TUNNEL I I I I l <C ___________

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SHAFT 5i

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X Si  !$ -

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BATTERY i. ~u- BATTERY  !

A I I J v  :

1

- ' A' /' C' EL . PIPE L ~'A' MCC l DUCTS o 37'-0' NSEB ELECTRICAL GEAR LAYOUT / SEPARATION l FIGURE I (SHEET 1 0F 2) o

ERRT E o 2 29 I

I L CLASS 2 MCC b -

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g co B' DIESEL GEN.

.B' GEN.PNL.

'B'ENG.PNL. l I L CLASS 2 MCC b ~

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'A' GEN.PNL. g

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l TDI D.G. BLDG.

ELECTRICAL GEAR LAYOUT / SEPARATION FIGURE l (SHEET 2 0F 2) l

ERPT E u 2 2 0 1 IN. ENCLOSED RACEWAY (TYPICAL)

& ~l 'A' l I,

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1 IN.

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DETAIL A I

WALL ,..' , i l 'A' l .*. l 'B' l r.

• '. I P.

DETAIL B l 8

LESSER DISTANCE IS USED ONLY .IF JUSTIFIED.

BY TEST OR ANALYSIS.  !

ALL DIMENSIONS SHOWN ARE WINIMUMS l ACCEPTABLE SEPARATION BETWEEN CONDUITS AND CABLE TRAYS IN THE NSEB AND D/G BLDG.

FIGURE 2 (SHEET 1 0F 3)

ERPT E o 220 f ,. WALL

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ENCLOSED RACEWAY DETAIL C (TYPICAL) p .D' u 1 IN.

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SOLIO 5 FT. h 'B. f COVER 1 *

-BARRIER h 'B' dY V l

- -Y --

,  ; .B' l- A 1 FT. 4 , I I 1 FT.

A A 1 IN.

• LESSER DISTANCE IS USED ONLY IF JUSTIFIED DETAIL D

_BY _ TEST OR ANALYSIS.

ALL' DIMENSIONS SHOWN ARE MINIMUMS l

ACCEPTABLE SEPARATION BETWEEN l CONDUITS AND CABLE TRAYS IN THE '

NSEB AND D/G BLDG.

FIGURE 2 (SHEET 2 0F 3) l

ERPT E O E 40-  !

ENCLOSED RACEWAY (TYPICAL) i at1 N. .

f h 'N' , /,

/- ,, BARRIER SOL 10 /,- _

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A A OR TO WALL I IN.

DETAIL E DETAIL F l

i CONTAINS ONLY 1 IN*  ;

' ~

LOW ENERGY INSTRUMENTATION

'A' 'N' CIRCUITS DETAIL G DETAIL H

• LESSER DISTANCE IS USED ONLY IF JUSTIFIED.

BY TESI QR ANALYSIS.

_ALL DIMENSl0NS SHOWN ARE MINIMUMS ACCEPTABLE SEPARATION BETWEEN CONDUITS AND CABLE TRAYS IN THE NSEB AND D/G BLDG.

(_ -

FIGURE 2 (SHEET 3 0F 3)

ERPT E o 2 20i Attachment 1, Sh. 1 of 5 l 8.2.2.11 Evaluation of the Physical Layout of Electrical Distribution System Equipment Electrical distribution system equipment is arranged to minimize the vulnerability of vital circuits to physical damage as follows:

A. The two startup transformers are outdoors, physically separated from each other. Lightning arresters have been provided on the high voltage side for surge protection. The transformers are protected by automatic deluge type fog systems to extinguish oil fires quickly and prevent the spread of fire. Transformers are isolated by fire walls to minimize their exposure to fire and mechanical damage.

B. The unit auxiliary 6900-volt switchgear, 4160-volt switchgear, 480-volt switchgear, and motor control centers are in areas where exposure to mechanical, fire, and water damage is minimized.

Equipment is coordinated electrically to operate safely under normal l and short circuit conditions.  :

C. Nuclear service 4160-volt and 480-volt switchgear are in seismic l Category I structures. Physical separation of redundant power i systems has been maintained throughout. Equipment is coordinated )

electrically to operate safely under normal and short circuit '

conditions.

D. 480-volt motor control centers are in areas of electrical load concentration. Nuclear service motor control centers are in a seismic Category I structure. Physical separation of redundant power ',

systems has been maintained throughout.

i E. Station batteries and associated chargers and inverters serving the  ;

protective systems loads are independent Class I installations housed in separate rooms within the Auxiliary Building and Nuclear Services Electrical Building, which are seismic category I structures.

F. Non-segregated, metal-enclosed 12,470 , 6900 , and 4160-volt buses are used for major bus runs where large currents are carried. The routing of these metal enclosed buses minimizes their exposure to mechanical, fire, and water damage. Silicone foam has been injected in all 480-volt, 4160-volt and 6900-volt bus ducts at all fire wall penetrations.

G. The application and routing of control, instrumentation, and power cables minimizes their vulnerability to fire. The cables have been chosen by using conservative margins with respect to their current carrying capacities, insulation properties, and mechanical construction, and are of a flame resistant construction. Power and control cable insulations for use throughout the plant have been selected to minimize the harmful effects of radiation, heat, and humidity. Appropriate instrumentation cables are shielded to minimize induced voltage and magnetic interference. Wire and cables related to safety features and reactor protective systems are routed and installed to maintain physical separation of redundant channels.

l 8.2-9 Rancho Seco USAR Amendment #4

Attachment 1, Sh. 2 of 5 Circuits, trays, conduit, and electrical equipment which are part of Class I systems are color coded (see Chapter 7) to help verify that

!- channel separation is actually achieved.

l H. The separation of redundant cables of the reactor-protection system and safety features actuation system circuits is accomplished by spatial separation in accordance with the following criteria:

1. separate cable tray conduit and penetration systems are installed for the following classes of cable: 15 kV, 5 kV, 600-volt power and control, and instrumentation cable. Class I 600-volt power and control cables of one channel are run together in trays that belong to the same channel. Class I instrumentation circuits are routed in rigid metal conduits as explained'in (2) below.

2. Reactor protection system and safety features actuation system instrumentation each have their channels routed in separate conduits and are physically separated from each other throughout the plant.

3. Reactor protection system and safety features actuation system-power and control, Channels A and B, are separated physically and have separate raceway systems. Non-safety related circuits may be run in these trays.

4. The channel separation criteria is met in both the reactor-protection system and the safety features actuation system.

, 5. Power and control circuits are not mixed with' instrumentation i l circuits in any raceway for any system.

1 1

6. The minimum horizontal distance between trays of different channels is 3 feet, O inches.

7. Paralleling trays of different channels in a vertical stack is not permitted.

8. The minimum vertical distance between trays of different-channels crossing each other is 18 inches. Additionally, at tray crossings, a 1/4 inch thick Haysite polyester board fire barrier has been installed between the trays for protection.

9. The maximum percentage fill in redundant trays is 40 percent', i and wherever possible, it is kept at a much lower value. j i 10. All electrical cables installed in cable trays are covered with flame resistant jackets.

11. Base ampacity rating of cable is as conservative as or more conservative than, that established in published IPCEA standards l and is in accordance with manufacturer's standards. Cables are Rancho Seco USAR 8.2-10

ERPIEO220 Attachment 1, Sh. 3 of 5 l

selected on the basis of 100 percent load factor. Power cables are sized for 125 percent of full load current of the equipment served. Where cable is routed through several types of installation conditions (conduit, cable tray) cable ampacity is selected for the worst condition.

12. Fire protection systems (sprinklers) are provided near the electrical penetrations outside of the containment building.

Fire protection systems (carbon dioxide) are'provided in the cable shafts. Adequate fire extinguishers are provided inside-the containment building (see Section 1.4.3).

13. In addition to the color identification of cables and raceways l as explained in Section 7.1.4, each cable is identified at l termination points by affixed markers. Markers have the cable i

number plus a color mark corresponding to the channel color. i Non-safety related cable markers have no color mark. Cable l raceways are identified by coded markers. '

Trays or conduits used for reactor protection or safety features actuation channels have diamond-shaped color spots corresponding to the channel color code. For example, a Channel A tray is identified with red tray markers and.contains only red-marked and/or white-inarked, black-jacketed cables (non-safety related c.sbles routed in safety related raceways are identified with white marking). Although cables that are not part of. reactor protection or safety features actuation channels may share a

' l

, safety related raceway, in no case will'these cables cross from i l

cne channel's raceway to another and thus form a bridge. l l

14. Protection system safety features system and Class IE electrical system components mounted on control boards, panels, and relay

i. racks are designed with physical separation between redundant j wiring and components.

]

Generally, redundant channel wiring enters the control panels in conduits. Most redundant wiring inside the control panels is separated by a steel barrier. However, wiring which is common j to two redundant channels exists. The jackets of these wires l are identified with the color of 'the channel energizing them.

Physical separation has been provided between redundant switches and wiring for Class 1 breakers 3A05, 3A21, 3B05, 3B21, 4A01, 4A09, 4A10, 4B01, 4B04, 4B05, and 4B11, and for the diesel generator speed and voltage controls on H2ES, the electrical switching panel. H2ES is a seismic Class 1 panel.

The quality assurance program defined in Chapter 1 as::ures compliance with the separation criteria during design and installation. Specific procedures have been set up by means of the computerized circuit and raceway schedule to facilitate coordination of design information in the field.

Rancho Seco USAR 8.2-11 i

ERPT E 0220 Attachment le Sh. 4 of 5 The following examples of cable identification extracted from the computerized Rancho Seco circuit schedule illustrate the differentiation made between safety related cables of different channels or trains and non-safety related cables run in safety trays:

a. Non-safety related cables run partially in safety related trays and conduits.

Scheme cable number 1A3AS484B1 connecting level switch number LSHL48413 to annunciator cabinet number H4RA is routed through the following raceways (trays and conduits):

L64002, L64018, L64075, L45191, L44CF1, 744CC1, 744CB1, 744CG1, 744GH1, 744BP1, L44AU1, 744L1, 744M1, 744T1, l 744AB1, and 744V64 The third character in the scheme cable number indicates  !

this cable is for a Quality Class 3 system. The above routing for this cable shows a run through four "L" conduits, ten non-safety related trays and two "L" trays. j A letter L, M, P, or W.as the first character in the l raceway indification number indicates that the conduit or I tray is safety related: the "L" designation is used for Channel A conduits or trays; "M" for Channel B, "P" for Channel C; and "W" for Channel D. A numeral as the first ,

character in the raceway identification number indicates l the conduit or tray is not safety related. Tray identification numbers have a combination of letters and numerals following the first character. Conduit identification numbers have only numerals following the first character.

b. Non-safety related cable run entirely in non-safety related trays and conduits.

Scheme cable number 113L2804A connecting panels SIL28 and H3CRP is routed through the following trays and conduits:

740012. 740AE1, 740AD1, 740AC1, 743N1, 743M1, 743L1, 743BE1, 743T1 and 743V75.

The third character in the scheme cable number indicates this cable is for a Quality Class 3 system. The routing for this cable shows the cable is run entirely through non-safety related conduits and trays,

c. Safety related cable run entirely in safety related trays and conduits.

Scheme cable number 121A107A connecting motor operated valve SFV26037 and motor control center S2A1 is routed through the following trays and conduit: RED L44V63, L44BU1, L,4AK1, L44AL1, L44AM1, L44CF1, L44CEl, L44V36, Rancho Seco USAR 8.2-12

EFNrr E0220 Attachment 1, Sh. 5 of 5 L43V36, L39BNS, L39BJ5, L39AX5, L39R5, L39Q5, L39P5, L39N5, L39M5, L39L5, L39G5, L39F5, and L39304 RED.

The third character in the scheme cable number indicates this cable is for a Quality Class 1 system. The routing for this cable is in safety related raceways only. For safety related circuits the routing in the circuit schedule and on the pull card starts and ends with the color of the l safety channel to which the cable belongs. In this case l (Channel A cable) red paint is used to mark a continuous '

red stripe on two sides of the cable jacket. The possum cable markers attached to both ends of the cable contain 4 the cable scheme number, to and from locations, and a red  !

color dot. Individual conductors are identified with heat shrinkable sleeves marked with the cable scheme and conductor number, with a piece of red heat shrinkable tube. After a cable is pulled, inspected and approved, the "to" and the "from" cable connection cards are used for making wiring connections. (The "to" and the "from" cable connection cards each contain the scheme cable number and the number for each conductor in the cable and corresponding color code where applicable. The markers are attached to the cable and to the individual conductors and j the cable is terminated in accordance with the connection t cards and connection drawings. The terminations are then inspected.

Electrical testing is performed to assure the integrity of all circuits and their proper connections.

8.2.3 SOURCES OF AUXILIARY POWER 1 8.2.3.1 Description of Power Sources 8.2.3.1.1 Offsite Power i

As previously described, all of the normal power supply to plant auxiliary j loads is provided through the unit auxiliary transformers connected to the i generator bus.

Power to all nuclear services auxiliary loads is provided by both startup transformers, which are connected to the 220-kV system. During normal operation, one of the 6900-volt buses is supplied by unit auxiliary transformer No. 1. The other bus is supplied by startup transformer No. 1.

The unit auxiliary transformers, as well as the startup transformers, are sized to carry full plant auxiliary loads.

Upon separation of the unit from the 220-kV system both the reactor and the turbine generator will be tripped. If power is not available from the unit auxiliary transformers, it will be obtained from the startup transformers.

One 4360-volt winding of startup transformer No. 2 is normally connected to Rancho Seco USAR 8.2-13 Amendment #4 l