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Page 1 of 12 DSAR-8.5 Electrical Systems Initial Cable Installation Design Criteria Rev 0 Safety Classification: Usage Level:
Safety Information Change No.: EC 69283 Reason for Change: This section is being updated to reflect the permanent cessation of operations of Fort Calhoun Station. The contents of this section have been changed to remove any information which is not applicable during decommissioning.
Preparer: T. McDonald Fort Calhoun Station ARCHIVED TEXT*
- DSAR pages labeled as "ARCHIVED TEXT" are pages with text which is not revised or updated. Information on "ARCHIVED TEXT" pages is A) of historical nature significant to the original licensing basis of the plant OR B) not meaningful to update.
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Table of Contents 8.5 Initial Cable Installation Design Criteria ........................................................................ 4 8.5.1 Cable Separation Criteria ................................................................................. 4 8.5.2 Cable Protection Against Missiles .................................................................... 7 8.5.3 Electrical Penetration Separation Criteria for the Containment Building ........... 8 8.5.4 Cables .............................................................................................................. 9 8.5.5 Fire Protection Requirements for Cables ........................................................ 11 8.5.6 Process Instrumentation Inside Containment Building ................................... 12
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List of Figures The following figures are controlled drawings and can be viewed and printed from the listed aperture card.
Figure No. Title Aperture Card 8.5-1, Sheet 1 Cable and Conduit Schedule Notes .................................................. 36569 8.5-1, Sheet 2 Cable and Conduit Schedule Notes .................................................. 45962 8.5-1, Sheet 3 Cable and Conduit Schedule Notes .................................................. 45963 8.5-1, Sheet 4 Cable and Conduit Schedule Notes .................................................. 45964 8.5-1, Sheet 5 Cable and Conduit Schedule Notes .................................................. 45965 8.5-1, Sheet 6 Cable and Conduit Schedule Notes .................................................. 45966 8.5-1, Sheet 7 Cable and Conduit Schedule Notes .................................................. 45967 8.5-2 Cable Room Tray and Conduit Layout Plan, Elevation 1025' 0" and Sections. ........................................................................................... 12309
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8.5 Initial Cable Installation Design Criteria The following summarizes the cable installation design criteria intended to preserve the independence of redundant Reactor Protective systems and of those systems designed as Engineered Safeguards and other safety related systems. The Cable and Conduit Schedule Notes, Figure 8.5-1, provides the standard design criteria for cables and conduits. Deviation from the standard criteria is acceptable provided an analysis has been completed which justified the deviation.
8.5.1 Cable Separation Criteria Cable separation criteria of redundant Reactor Protective and Engineered Safeguards circuits are as follows:
- a. Redundant Reactor Protective and Engineered Safeguard circuits are routed from their sensors to the cable room in separate cable trays, conduits, containment penetrations and junction boxes.
- b. Cables are identified according to the notes shown in Figure 8.5-1.
These notes ensure segregation of redundant circuits with special emphasis placed on Reactor Protective and Engineered Safeguard circuits. See notes numbers 2, 5, 7, and 15 of Figure 8.5-1.
- c. Redundant Reactor Protective and Engineered Safeguard instruments are identified by tag numbers prefixed A, B, C, or D followed by a slash (/) in agreement with the cable prefix.
- d. The auxiliary and containment building cable trays are divided into four basic systems. These systems are identified on the drawings as EA, EB, EC, and ED. These designations agree with the cable numbering system as stated in Figure 8.5-1.
Two tray systems are assigned to each floor with a minimum horizontal separation of 2-3". Where this minimum horizontal separation can not be maintained suitable metallic barriers are installed.
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The cable tray systems are assigned as follows:
Location Floor Elevation Tray Systems Auxiliary Building 971' EA, EB Auxiliary Building 989' EA, EB Auxiliary Building 1007' to 1013' EC, ED Auxiliary Building 1025' EA, EB Auxiliary Building 1036' EC, ED Containment Building 994' A - North half EB - South half Containment Building 1013' C - South half ED - North half Containment Building 1045' o cable trays Cables to Reactor Protective and Engineered Safeguard equipment whose prefix differs from that of the nearest tray system are routed separately to the matching tray system.
- e. The cable spreading room contains the cable tray, conduit, and junction\box system for the routing of cables to the control boards, auxiliary instrument panels and the ERF computer. In addition, the cable spreading room contains items to support the operation of the plant including such items as fire extinguishers, fire detectors and panels, fire suppression (Halon) for both room 70 and control room walk-in cabinet, emergency lighting and Gaitronics communication, control room sanitary drain, control room air conditioner room floor drains, mechanical equipment drain line and isolation valve, ventilation dampers, 800 mhz radio system junction box JB-622a, electrical power receptacles, condenser vacuum gauge lines, cables abandoned in place, control room delta pressure sensor, and lighting including panel LP-7.
The cable tray system in the cable room does not have covers since the installation consists mainly of instrument and control cables, basically 120V AC, 125V DC, or low energy signal and computer control circuits.
The LP-7 120/208 VAC supply is run in conduit in the cable spreading room.
There are no 4160V or 480V power cables installed in cable trays in the cable spreading room.
The cable tray and conduit arrangement is shown on Figure 8.5-2. All trays are run in vertical banks with a nominal vertical separation of 12 inches from the bottom of one tray to the bottom of the next tray.
Engineered Safeguard cables are separated by metallic barriers right up to the control boards in accordance with note number 7 of Figure 8.5-1.
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- f. The E prefixed cables inside the screenhouse and between the plant building and screenhouse are routed in separate conduits, tray sections, or in separate duct bank conduits (plastic tubes embedded in concrete).
The pull box and manhole layout is as follows:
- 1. Pull boxes There are two pull boxes along the outside of the south auxiliary building wall. The pull boxes are divided in sections by asbestos - cement compound plates. One pull box contains EA and EC cables in separate sections, and the other pull box contains EB and ED cables, also in separate sections. In conformance with Note 22 of Figure 8.5-1, a metallic barrier is placed inside each section containing E prefixed cables in order to segregate them from the non-E prefixed cables.
- 2. Manholes There are two manholes between the pull boxes and the screen house. The cables are in cable trays and the routing is in conformance with the Cable and Conduit Schedule Notes (Figure 8.5-1). There is a 6" thick concrete wall separating cable trays with EA and EC cables from cable trays holding EB and ED cables.
- g. The criteria governing the separation of power cables from those used for control and instrumentation are stated in notes number 10, 11, 12 and 13 of Figure 8.5-1. In general these cables are grouped in separate trays and the notes in Figure 8.5-1 apply to those areas where physical limitations, etc., preclude this.
- h. The intermixing of non-vital cables with Reactor Protective or Engineered Safeguard cables is prohibited by note number 22 of Figure 8.5-1.
- i. The cable for each redundant sensor of a protection channel is assigned a different prefix (EA, EB, EC, or ED) and is routed separately in accordance with the notes on Figure 8.5-1. If cables of two different protection channels are located in the same area, note number 7 of Figure 8.5-1 ensures that only those cables with the same prefix will be grouped together.
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- j. Cable separation criteria do not apply to non-safety related fiber optic cable constructed 100% of non-metallic (electrically nonconductive) materials. There is not EMI/RFI interaction with fiber optic cabling.
There is no possibility of propagating a fault between circuits due to the exclusive use of non-metallic materials so the purpose of cable separation is maintained.
8.5.2 Cable Protection Against Missiles The cable installation design criteria described in DSAR Sections 8.5.1, 8.5.3, and 0 along with the following summary comprise the methods used to ensure that in areas containing high pressure piping or where mechanical damage is possible, such as from missiles generated by rotating equipment, no single credible incident could damage more than one cable raceway of a redundant system. Redundant circuits referred to in this summary are those associated with Reactor Protective and Engineered Safeguards systems.
The methods employed for the protection of these cables are as follows:
- a. Each redundant channel is routed in a separate cable tray system.
- b. Each redundant channel is routed in separate conduits and junction boxes.
- c. Each redundant channel is routed through a separate containment penetration.
- d. Only two out of the four redundant cable tray systems are assigned to each floor elevation and these are horizontally separated.
- e. Cable trays are installed with covers where required (See USAR Appendix M Section 4).
- f. In the auxiliary building main cable tray systems are located in corridors where the amount of rotating equipment is at a minimum.
- g. In the containment cable trays are located in protected areas (see DSAR Section 5.8.1). When a redundant electrical component is located inside the shield walls surrounding the reactor coolant loops, conduit is used.
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8.5.3 Electrical Penetration Separation Criteria for the Containment Building The separation criteria for the electrical penetrations in the containment building are as follows:
Electrical penetrations are of the canister type. A description of the canister is included in the USAR Section 5.9.3. An arrangement drawing showing the spacing and service of each canister is shown on Figure 5.9-16. This figure shows that separate canisters are assigned for the following class cables and is in accordance with Figure 8.5-1. The platform and floor shown on Figure 5.9-16 exists on both sides of the containment wall.
4160V AC Power A 4160V AC Power B 4160V AC Power C 4160V AC Power D Power EA (480V, 120/208V and 125 DC)
Power EB (480V, 120/208V and 125 DC)
Power EC (480V, 120/208V and 125 DC)
Power ED (480V, 120/208V and 125 DC)
Power A and C (480V, 120/208V and 125 DC)
Power B and D (480V, 120/208V and 125 DC)
Control EA (125V DC and 120V AC)
Control EB (125V DC and 120V AC)
Control EC (125V DC and 120V AC)
Control ED (125V DC and 120V AC)
Control A and C (125V DC and 120V AC)
Instrumentation EA Instrumentation EB Instrumentation EC Control B and D (125V DC and 120V AC)
Instrumentation EA Instrumentation EB Instrumentation EC Instrumentation ED Instrumentation A and C Instrumentation B and D Coax EA Coax EB Coax EC Coax ED
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Reactor Protective and Engineered Safeguard cables with different prefixes are routed through separate canisters. Cables are routed from the canister in separate tray or conduit in accordance with the cable separation criteria stated in DSAR Section 8.5.1.
8.5.4 Cables Cable criteria are as follows:
- a. Cable tray loading is in accordance with notes numbers 17, 18, and 20 of Figure 8.5-1. Note number 17 applies to 5 kV power cable only. Note number 20 is further described as follows:
- 1. 600 Volt Class E Prefixed Power Cable The fill in cable trays shall generally not exceed 40 percent of the rectangular area derived from the height of the cable tray side times the cable tray width. Fill exceeding 40 percent shall be justified by analysis.
The 40 percent fill is defined as the sum of the cross-sectional areas of all cables in the tray. For triplexed cable only, the cross-sectional area includes the spaces between the three conductors as enclosed in an encompassing circle.
- 2. 600 Volt Class Non-E Prefixed Power Cable In general the same criteria as for E prefixed cable shall apply.
- 3. 600 Volt Class E and Non-E Prefixed Control Cable Used For 125 Volt DC and 120 Volt AC Control Circuits The fills in cable trays shall generally not exceed a maximum of 50 percent of the rectangular area derived from the height of the cable tray side times the cable tray width. Fill exceeding 50 percent shall be justified by analysis.
The 50 percent fill is defined as the sum of the cross-sectional areas of all cables in the tray.
- b. Cable environmental qualification is summarized in the EEQ Manual.
- c. Cable splicing in cable trays is used only for connection of incoming and outgoing cables with containment electrical penetration conductors.
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- d. Cable ampacity derating is in accordance with established methods as described in IEEE Publication No. S-135 Insulated Power Cable Engineers Association (IPCEA) (currently ICEA) Publication No. 426, titled, Power Cable Ampacities, Volume I - Copper Conductors.
An ambient temperature of 50° C. is assumed for exposed conduit and cable tray and an ambient temperature of 20° C. is assumed for underground ducts. The maximum allowable continuous conductor temperature is 90° C. Cable ampacity can then be determined by using the assumed ambient and allowed conductor temperature limit to adjust the rated cable ampacity at its rated ambient and conductor temperature.
- e. As part of the electrical system's design, power cables have been oversized to ensure equipment operability. In general, a 125% full load current criteria per National Electric Code Article 430-22 and derating procedures outlined in "d" above were used.
- f. Cable and wireway markings
- 1. Generally, whenever a conduit enters or leaves a box or tray, it is marked on each side of the box or at the tray, in accordance with the Cable and Conduit Schedule, with the identifying number of the cable or cables in the conduit run to which they are attached.
- 2. Cables are identified with suitable markers in accordance with the identifying number assigned in the Cable and Conduit Schedule.
Engineered Safeguards cables are a subset of Safety Related cables which are identified by an "E" prefix and are separated for easy identification by their distinctive colored jacket or jacket banded with colored tape every three feet as listed below:
Cable Number Prefix Jacket Color EA Red EB Green EC Yellow ED Blue
- 3. Wires are identified by individual wire numbers or letters at both ends of wires and at terminal boards. Wire identification corresponds to that shown on the elementary and connection diagrams.
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8.5.5 Fire Protection Requirements for Cables
- a. Flame resistance qualifications The flame resistance qualification of cables originally installed in trays generally complies with IEEE 383-1974 (for the purposes of flame testing). Currently, any new cable installed in cable trays is purchased as IEEE Standard 383 certified.
The NRC stated in its SER dated August 23, 1978, Item 4.8, Electric Cables, that "Although IEEE Standard 383 was not in existence at the time Fort Calhoun cabling was purchased and installed, manufacturers which supplied most of the cables have subsequently certified that these cables are capable of passing the test outlined in IEEE 383-1974. In addition, the licensee has successfully conducted tests on the control and power cables, generally following the provisions for alternate test method described in IEEE Standard 383-1974. We find that the electrical cables adequately comply with IEEE Standard 383-1974 and meet BTP 9.5-1."
- b. Temperature monitoring of cables The conservative approach of cable tray loading and derating procedures, outlined in DSAR Section 8.5.4, precludes the necessity of monitoring cable temperatures in trays.
- c. Fire detection and alarm system, which alerts control room operators of a fire, is described in DSAR Sections 9.11.4.1 and 9.11.4.2.
- d. Fire stops There are fire stops for slots and openings in walls and floors through which cable trays pass.
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8.5.6 Process Instrumentation Inside Containment Building The criteria for the process instrumentation inside the Containment Building were as follows:
- a. Process instruments within the containment are located in shielded areas accessible for maintenance.
Redundant instruments for safety instrumentation are identified by tag numbers prefixed by a capital letter A, B, C, or D followed by a slash(/).
Sensing lines to these redundant instruments are run from separate sensing points. Redundant instruments within the containment for a safety channel are located on physically separate racks or on a common rack. However, where these instruments are located on a common rack metal barrier plates are provided to maintain separation between all A/,
B/, C/, and D/ instruments and lines. Redundant instrument racks were not placed closer than three feet from each other unless they were separated by a wall or furnished with a metallic plate on their sides.
Redundant instrument sensing lines were not placed closer than three feet from each other unless they are separated by an adequate shield (steel plate, steel channel, concrete wall, etc.) to protect the lines against mechanical injury. In the case where two redundant sensing lines cross each other the mechanical separation was provided for a radius of at least two feet from the point of crossing.
- b. All cable trays in the containment containing redundant instrumentation leads are located in a protected area. This area is outside the concrete shield walls surrounding the reactor coolant loops (see DSAR Section 5.8.1). When thermocouples or RTD's are located inside these walls, their cables are routed in conduit.
Cables of redundant instruments are identified in accordance with Figure 8.5-1. To maintain separation, these cables are generally routed in the following manner to the penetration area.
Cables prefixed EA - Routed counterclockwise above floor elevation 994' Cables prefixed EB - Routed clockwise above floor elevation 994' Cables prefixed EC - Routed clockwise above floor elevation 1013' Cables prefixed ED - Routed counterclockwise above floor elevation 1013'