ML17334B619

Responds to 961202 RAI to Resolve Concerns Re thermo-lag Related Ampacity Derating Issues

ML17334B619
Person / Time
Site:	Cook
Issue date:	03/20/1997
From:	Fitzpatrick E INDIANA MICHIGAN POWER CO. (FORMERLY INDIANA & MICHIG
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML17333A823	List: ML17333A822 ML17334B619
References
AEP:NRC:0692DL, AEP:NRC:692DL, TAC-M85538, TAC-M85539, NUDOCS 9703260168
Download: ML17334B619 (40)

Text

CATEGORY j.

REGULAT INF RMATION DISTRIBUTION STEM (RIDS)

ACCESSION,'NBR:9703260168 DOC.DATE: 97/03/20 NOTARIZED: NO DOCKET FACIL':50-315 Donald C. Cook Nuclear Power Plant, Unit 1, Indiana M 05000315 50-316 Donald C. Cook Nuclear Power Plant, Unit 2, Indiana M 05000316 AUTH. NAME AUTHOR AFFILIATION FITZPATRICK,E.E Indiana Michigan Power Co. (formerly Indiana 6 Michigan Ele RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)

SUBJECT:

Responds to 961202 RAI to resolve concerns re thermo-lag related ampacity derating issues.

DZSTRZBUTZON CODE: A029D COPZES RECEZVED:LTR I ENCL I SZEE! +Zg TITLE: Generic Letter 92-008 Thermo-Lag 330 Fire Barrier NOTES:

RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD3-3 LA 1 0 PD3-3 PD 1 1 HICKMAN,J 1 1 INTER . RELIC 1 1 NRR/DE/EELB 1 '

NRR/DRPW/PD3-1 1 1 NRR/DSSA/SPLB 1 1 RGN3 FILE 1 1 EXTERNAL: NOAC 1 1 NRC PDR 1 1 NOTE TO ALL "RIDS" RECIPIENTS:

PLEASE HELP US TO REDUCE WASTE! CONTACT THE DOCUMENT CONTROL DESKI ROOM OWFN SD-5(EXT. 415-2083) TO ELIMINATE YOUR NAME FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEED!

TOTAL NUMBER OF COPIES REQUIRED: LTTR 10 ENCL 9

Indiana Michigan Power Company 500 Circle Drive Buchanan, MI 49107 1395 INDIANA NICIIIGAN PQWM March 20, 1997 AEP:NRC:0692DL Docket Nos ~: 50-315 50-316 U. S . Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D C ~ ~ 20555 Gentlemen:

Donald C. Cook Nuclear Plant Units 1 and 2 ADDITIONAL INFORMATION REGARDING THERMO-LAG RELATED AMPACZTY DERATING ISSUES (TAC NOS. M85538 AND M85539)

IN RESPONSE TO A REQUEST FOR ADDITIONAL INFORMATION

References:

1. Letter AEP:NRC:0692CV, RAI regarding generic letter 92-08, "Thermo-Lag 330-1,Fire Barriers", ED E. Fitzpatrick to USNRC Document Control Desk, February 4, 1994.

2. Letter AEP:NRC:0692DA, follow-up to RAZ regarding generic

. letter 92-08, ",Thermo;Lag 330-1 Fire Barriers",

E. E. Fitzpatrick to USNRC Document Control Desk, December 21, 1994 '

~ Letter AEP:NRC:0692DD, response to follow-up to RAI regarding generic letter 92-08, "Thermo-Lag 330-1 Fire Barriers",

ED ED Fitzpatrick to USNRC Document Control Desk, March 29, 1995 4 ~ AEP:NRC:0692DF,

'etter additional information regarding thermo-lag related ampacity derating calculations, TAC nos ~ M85538 and M85539, ED ED Fitzpatrick to USNRC Document Control Desk, May 12, 1995 your letter of December 2, 1996, we were requested to supply

'y additional information needed to resolve concerns regarding the ampacity derating factor determinations for Cook Nuclear Plant units 1 and 2. These concerns are addressed in the six attachments to this letter.

Attachment 1 provides responses to your requests'ttachment 2 provides a table that depicts the correlation between the predicted and measured ampacities ~ Attachment 3 provides the model computer code. Attachment 4 provides test report CL-492, "Ampacity Test for Power Cables in Randomly Filled Trays" ~ Attachment 5 contains comparison tables that provide base information regarding trays and 01 68 S 70320 PDR Ao<<K 0S0003gg pLg I I POR n( OOJO HiHIIIHIIHHHIIHIIH!iH!lHIHlHHIII

U. S. Nuclear Regulatory Commission AEP: NRC: 0692DL Page 2 conduits, cable full load amperes, and comparison of calculated ampacities vs ICEA ampacities. Attachment 6 provides an "Ampacity vs Depth of Fill Plot for 812 AWG Copper Wire".

Sincerely, p~

E. E. Fitzpatrick Vice President vlb Attachments CC A. A. Blind

,A. B. Beach MDEQ - DW Ec RDP NRC Resident Inspector J. R. Padgett

ATTACHMENT 1 TO AEP:NRC:0692DL RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING

'HERMO-LAG RELATED AMPACITY DERATING ISSUES FOR COOK NUCLEAR PLANT (TAC NOS. M85538 and M85539)

AEP:NRC:0692DL Res onse to NRC Re est for Additional Information

1.0 BACKGROUND

The initial Request for Additional Information (RAZ) response, AEP:NRC:0692CV, Attachment 2, inclu'ded a list of Appendix R safe shutdown cables covered with Thermo-Lag 330-1 Barriers (Thermo-Lag) at Cook Nuclear Plant (CNP). This cable population was comprised of control, instrumentation, and power cables.

The focus of the ampacity derating analysis presented in this response has b en reduced to strictly power cables. Control and instrumentation cables would have to be derated 73-. or more in order for their loadings to be a concern, therefore they are, not considered as part of this derating analysis.

Additionally, junction boxes and tray junction pans are not considered as part of this derating analysis due to the large enclosure surface areas available for heat dissipation compared to the raceways that carry these same cables.

Also listed in AEP:NRC:0692CV, Attachment 2 were six installations where four inch conduit is embedded in= concrete forming a vertical conduit bank. This bank is attached to a wall and the outer sides are covered with Thermo-Lag. Based on a review, of each cable in these banks, including a comparison between each circuit Full Load Amperes (FLA) versus maximum ampacity of the cable (per design guidelines), a minimum margin of 25% was identified. We believe this margin is sufficient for any derating due to installation of Thermo-Lag on the vertical conduit banks. Therefore these installations have also been excluded from this derating analysis.

AEP:NRC:0692DL Attachment 1 Page 1 of 21

iaaf The following is a list of raceways that contain the power cables that are considered in this derating analysis. These power cables are identified in Attachment 5.

A endix R Racewa s Trays Conduits 1-AX-P1 8003R-1 1-AI-P2 8004R-1 1-AI-P4 8004G-1 1-AZ-P8 8026R-1 1-AZ-P9 8505R-1 1-A-P20 8506R-1 2-AZ-P3 8003R-2 8004R-2 8004G-2 8154G-2 8155G-2 8744R-2 Non-A endix R Tra s 2-A-P2 2-AZ-P10 "Non-Appendix R Trays" are defined as those power trays (containing non-Appendix R cables) that are commonly wrapped with Appendix R control trays.

2.0 QUESTIONS 2.1 General modeling concerns 2.1.1 Request Although the licensee submitted the results of its analysis for one cable tray and several conduits, there was no overall summary provided to assess the full range of fire barrier configurations installed at CNP. The licensee is requested'o provide a summary of all ampacity derating assessment results for all Thermo-Lag enclosed raceway configurations (e.g. tray, conduit, air drop) installed at CNP.

AEP:NRC:0692DL Attachment 1 Page 2 of 21

Response

Summary ampacity derating assessment results for all the Thermo-Lag enclosed raceway configurations listed above are provided in Attachment 5. This attachment lists the ampacity derating of each cable within these raceways as the difference between FLA and ICEA ampacities as a percentage of the ICEA ampacity (0 margin). As a verification that- the loaded raceway generates less heat (watts per foot w/ft) than what would be required to r'each the cable qualification temperature, modelled and actual w/ft values are also listed.

It is our position that the cables listed in Attachment 5 have been appropriately derated given the large margins and the differences between the predicted and actual heat values. Information on the development of is provided in sections 2.3.2, 2.4.7 and 2.4.8.

Reques t The level of documentation provided is not adequate to complete a full evaluation of your ampacity assessments.

In general, there is no discussion of how the two parts of the licensee analysis methodology are made to work together, the example calculations do not provide enough information to verify the calculations, and the experiments purported to support validation of the thermal models are either not provided, or no direct one-to-one comparison of the experiments to modeling results is provided. The licensee is requested to provide further documentation in the areas stated above.

Response

A description of how the analysis methodology works is provided in section 2.3.2. Additionally, Attachment 2 demonstrates how the CNP thermal model was applied to a representative tray and conduit from the 1983 AEP Canton Test Lab tests. Applying the thermal model to tested raceways allowed for direct one-to-one comparisons to be made between predicted and actual values. The results of the comparisons demonstrated that there is a correlation between the predicted and actual calculated heat generated (w/ft) for both tray and conduit. Details of the comparison are provided both in section 2.3.2 and .

AEP:NRC:0692DL Attachment 1 Page 3 of 21'

2.1.3 t I ~ ~ Reques No discussion was provided as to how in-plant cable service loads were determined, which cables have been considered in the analysis, and the basis for the elimination of other cables from consideration. The licensee is requested to clarify how the above information was treated in its analysis.

Response

In-plant cable service loads are determined from the nameplate rating of the service load itself.

The cables considered in tnis derating analysis are listed, by their raceway, in Attachment 5. The "Background" section of this submittal contains the basis for the elimination of other cables from consideration.

2.2 Part 1 Analysis, Appendix A of Attachment 4 2.2.1 Recgxest The staff agrees with its contractor, SNL, that the information provided to date does not provide an adequate basis for validation of its assumption that the overall heat rejection capacity of a sparsely loaded cable tray can be partitioned to individual cables in proportion to the cable diameter. The limited information provided by the licensee (one plot with no supporting data and no indicated units) is unconvincing given the potential for minor errors in the calculation could lead to larger error in the final estimation of ampacity limits. The licensee has cited a set of experiments as the basis for this plot, and hence, for the validation of this methodology (see reference of Appendix C in Attachment 4). However, this documentation of these experiments was not provided for staff review. The licensee is requested to provide Appendix C as well as any other documentation to support the validation of the experiments cited in the licensee analysis.

AEP:NRC:0692DL Attachment 1 Page 4 of 21

Response

AEP test report NCL-492 is included as Attachment 4 of this letter. This test report is the Appendix C identified in AEP: NRC: 0692DF, Attachment 4. A detailed physical description of the test and testing protocol. can be found in section III "Test Method" of the attached test report gCL-492. The summary is included in section IV "Test Results" as well as the test data section, Appendix A, of test report NCL-492.

The purpose of the test was to determine the ampacity of power cables in randomly filled trays and show the relation of I vs. (d/Rac) / for various tray configurations. Figure A-1 (AEP:NRC:0692DF, Attachment

4) was plotted using the results of three tested tray configurations. The Y axis represents current, in amperes, for the cables tested in earth tray configuration. The X axis represents (d/R>c) d is diameter of each cable and Rac ~s I,

the where

a. c.

resistance.

2.3 Part 2, Analysis, Appendix B of Attachment 4 2.3.1 Request The assumption of equivalent annular regions appears to give inadequate treatment to the importance of surface area in heat transfer calculations. The actual rates of heat transfer are directly proportional to surface area; hence it is important that the thermal model use actual available surface areas in its formulation. The licensee should provide examples which encompass all raceway types installed to illustrate the effective heat transfer areas assum .d for each of the layers in its modeling and compare those assumed areas to the actual heat transfer areas available in the physical system.

Response

All raceways considered in this assessment are either conduit or 12" x 6" ventilated, open top tray. These raceways are covered with 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> rated Thermo-Lag. Each raceway has been modelled in its equivalent circular form. When modelling tray, the tray itself is not considered as a thermal layer since an open top.

it is ventilated with Therefore the only non-circular thermal layer modelled in the CNP raceway system is the Thermo-Lag that encases tray. This thermal layer is treated as circular by calculating its equivalent circular diameter.

AEP:NRC:0692DL Attachment 1 Page 5 of 21

Therefore, a 12" x 6" thermal layer would be modeled as a cylinder of diameter d = 2 x (h + w) /II or 11.46".

Modelling with such equivalent diameters does not change the actual surface areas in the physical system. This approach has been supported for CNP applications by the correlations noted between the thermal model and the 1983 Canton Test Lab data, described in section 2.3.2 and .

It should be noted. that 12" x 6" ventilated tray is the only type utilized at CNP for power cable applications.

Cable derating standards assume more "plate-like" tray (24" x 4") construction.

Regues t The analysis as provided in the submittal dated May 12, 1995, provided no meaningful validation of its analysis method for calculating cable ampacity limits and cable tray limiting heat rejection capacities. The licensee should provide for the direct comparison of predicted cable ampacity limits to those measured in experiments on the corresponding system in order to validate its calculations.

Response

Validation of model In applying the thermal model to tested raceways representative of those considered in this assessment, a w/ft value that is below what is calculated to be the actual w/ft of the tested raceway. This is considered conservat've since this predicted value establishes the "limit" for which other identical raceways must be below to be considered acceptable. Candidate raceways having a total heat value less than this "limit" ensures that the heat generated is less than the heat corresponding to a known temperature for actual loadings that is less than 90 C AEP:NRC:0692DL Attachment 1 Page 6 of 21

The CNP thermal model algorithm (Attachment 3) has been used to model a tray and conduit tested in 1983 at the AEP Canton Test Lab. Having applied this thermal model to previously tested raceways has validated that the model generates conservative results for CNP a lications. The conclusion that the model generates conservative results is based on the rationale described in the previous paragraph applied to the modelling results provided in Attachment 2. Specifically what has values that are below the calculated actual w/ft values that correspond to known temperatures for actual loadings that a"e less than the cable qualification temperature of 90oC Xt is important to note where modelled (predicted) ampacities and corresponding heat values are listed, that they correspond to a particular tray fill given cable size using only a single layer of width of a fill.

Therefore, care must be taken when comparing modelled ampacities with those published in national standards.

Further, the ampacity and w/ft values generated by the computer model should not be interpreted as derating values endorsed by CNP design standards. Rather they are calculated values that would be required for a given width, of a particular size cable, to generate the fill maximum qualified cable temperature (90'C) . Such values are used only for review and acceptance purposes.

Application of model in the review of raceways The model algorithm is used to predict a heat generated value (w/ft) that corresponds to a given conductor temperature rise, for a given set of cables, '.'. a given raceway. This value can be used as a "limit" for which other identical raceways can be compared to for acceptance (i.e. those identical candidate raceways must have a total heat value less than this limit thereby ensuring that the heat generated is less than the heat corresponding to a known temperature).

For those raceway configurations where there is only one size cable (e.g. conduit), the predicted w/ft may be taken directly from the program output. This w/ft value is then compared to the actual total w/ft for the subject raceway for review and acceptance purposes.

AEP:NRC:0692DL Attachment 1 Page 7 of 21

For those raceway configurations where there is more than one size cable (e.g. tray), che program is to be run for each different size cable with the number of cables specified as (actual fill width  : subject cable diameter) . The program will return a modelled ampacity (per conductor) and a corresponding modelled w/ft value (for entire tray) based on the tray loaded excl'usively with the subject cable size. This process is repeated for each different size cable contained within the tray.

The lowest modelled w/ft value is conservatively selected as the limit for which the actual total w/ft will be compared to for review and acceptance purposes.

Selecting the lowest modelled w/ft value is considered conservative as it is less than the sum that could be calculated to accurately account for cables of varying size.

For each raceway considered in this ampacity derating assessment, the predicted and actual w/ft values are listed are listed in Attachment S. Inspection of th se values for each raceway shows that the actual heat generated for each raceway is less than 50'; of the predicted heat generated.

Reques t The thermal model for the subject analysis is based on heat "ransfer correlations which were originally published in the 1929-1933 time frame. These correlations are badly dated, and the impact of using more modern correlations in the model should be assessed by the licensee.

Response

Given the correlation between the CNP thermal model and the 1983 AEP Canton Test Lab test results, as discussed in section 2.3.2, we do not believe that using more modern correlations would prove to be effective.

AEP:NRC:0692DL Attachment 1.

Page 8 of 21

Reques t It is stated of by the submittal AEP:NRC:0692DF, in the correlation for heat transfer from the development " the thermal cables to the surrounding air gap, that resistance per conductor will be the total number of conductors divided by the total thermal conductance" (see the first sentence in the paragraph immediately preceding Equation 20 of the licensee analysis). The licensee should further explain and clarify the basis, intent, and impact of this statement.

Response

The basis for implementing equation 20 listed in AEP:NRC:0692DF, is that this equation is performed on cables of identical diameter. This prevents anomalies from being introduced by analyzing more than one cable size at a time.

The intent of implementing equation 20, listed in AEP:NRC:0692DF, is to account for the contribution of the raceway airspace in the overall partitioning of total thermal resistance to individual conductors. This permits conductor ampacity for a group of cables, with a given fill width and size, to be calculated.

ampacity is then used to calculate the predicted heat This generated (w/ft) for the entire tray.

Recpxest Directly related to the comment regarding the heat transfer correlation from the cables to the surrounding air gap, the correlations for " the thermal resistance through relatively thin cylinders (i.e., cable jacket, tray, fire barrier)" (Equation 16 per the licensee Analysis) and for the "thermal resistance from the last surface to ambient" (Equation 21 per the licensee Analysis) each include a factor (n' described as " the number. of conductors within the section." This would appear to be, in effect, a thermal partitioning factor which is based on a simple conductor count and, as such, may be in direct conflict with the stated assumptions of the model described in "Appendix A" of Licensee AEP:NRC:0692DL Attachment 1 Page 9 of 21

Attachm nt 4 (where it is assumed that surface area will be the basis for thermal partitioning). The licensee should clarify the basis, intent, and implementation of this factor (n' as it is applied to each of these two equations and how this factor is applied when cables of different physical dimensions are present in a common cable trays.

Response

The basis for implementing equations 16 and 21, listed in AEP:NRC:0692DF, is that these equations are performed on cables of identical diameter. This prevents anomalies from being introduced by analyzing more than one cable size at a time.

The intent of implementing equations 16 and 21, listed in AEP:NRC:0692DF, is to account for the contribution of the material thermal layers in the overall partitioning of total thermal resistance to individual conductors. This permits conductor ampacity for a group of cables, with a given fill width and size, to be calculated.

ampacity is then used to calculate the predicted heat This generated (w/ft) for the entire tray.

Request The subject analysis treats all cable tray systems using a model based on circular geometries. This practice is said to have been validated based on the " excellent correlation between computer data and test data."

However, no evidence of such validation has been provided in the subject submittal. The licensee is requested to provide the technical jus"ification which validates its assumptions in this regard.

Response

Section 2.3.2 and Attachment 2 provide test results and calculations which validate the correlation between the computer data (thermal model) and the test data (1983 AEP Canton Test Lab data). This has been demonstrated for a typical tray and conduit configuration at CNP. Therefore we believe that modelling cable tray systems using the circular geometry approach detailed in section 2.3,1 is appropriate for CNP applications.

AEP:NRC:0692DL Attachment 1 Page 10 of 21

Request The correlation cited for the thermal resistance between the outer surface of the barrier and the ambient environment (Licensee Equation 21) applies only to pipes.

These correlations should not be applied to flat plate surfaces such as those which would be experienced around a cable tray.

Response

Given the geometry of our tray, the single layer practices and the correlation between the thermal model fill and test data, the adequacy of modeling our 12" x 6" tray in its equivalent circular form has been demonstrated to be appropriate for CNP applications. This has been demonstrated in section 2.3.2 and Attachment 2, where the predicted heat generated in a cable tray was found to be less than the actual calculated heat generated.

Reques t The analysis model provides no treatment of the effects of spacing on the radiative heat transfer behavior of the cables. Reduced view factors due to cable proximity might significantly reduce the predicted rates of radiant heat transfer. The licensee is requested to address how the effects of spacing should be accounted for in the radiative heat transfer correlations.

Response

No credit is taken for space between cables when implementing the CNP thermal model. In each run of the thermal model, the mass of cables.

fill width is assumed to l a solid That is to say, that for a tray with a total fill width of 4.2" that is comprised of cables of 0.2" O.D., the tray would have 4.2"/0.2" or 21 cables with no spaces between them.

Reques t The licensee is requested to provide information on the specific inputs used in any example case as well as any computer code which process the subject calculations.

AEP:NRC:0692DL Attachment 1 Page 11 of 21

Response

The code and inputs for example raceways are included as Attachments 3 and 2 respectively.

The computer program requires the following as input:

a. ambient temperature number of heat transfer layers equivalent outside diameter of layer thickness of layer dead airspace outside layer emissivity of surface thermal resistivity of layer number of cables temperature rating electrical resistivity of conductor specific inductive capacitance of insulation power factor of insulation thickne'ss of jacket thermal resistance of jacket number of conductors per cable circular inch area of conductor conductor diameter insulation diameter thermal resistivity of insulation AC/DC ratio emissivity of cable surface diameter of cable line to line voltage (KV) inferred temperature of zero resistance af conductor The ampacities and w/ft values generated by the computer

~ model should not be interpreted as derating values endorsed by CNP design standards. Rather they are predicted values that would be required for a given width, of a particular size cable, to generate the fill maximum qualified cable temperature (90'C) .

AEP:NRC.0692DL Attachment 1 Page 12 of 21

2.3.10 Request The licensee has apparently applied one or both of its thermal models to the analysis of cables in conduits as well as those in trays. The applicability of both licensee analysis models to conduits needs to be further clarified by the licensee. Specifically, the thermal model for cable trays is based on the unique configuration of "maintained spacing" for its power cables in cable trays. This same factor cannot generally be assumed to exist for cables in condui(:s. The licensee should provide an explicit discussion of the applicability of its two thermal models (the "Appendix A" surface area based heat load partitioning model and the "Appendix 8" direct thermal analysis model) to conduits, and should discuss how these models were implemented for conduit analyses.

Response

The thermal model is based on current carrying conductors housed in cylindrical raceways. As explained in 2.3.7, cable tray is treated as a cylindrical raceway, therefore the thermal model is directly applicable to both cables housed in conduit and cable trays.

The design standard for conduit at CNP is such that only one power cable may be run in any conduit, therefore the matter of maintaining separation between cables is not a concern with respect to conduit.

2.4 Attachment 5, Representative Calculation Results 2.4.1 Request A nominal comparison between the licensee ampacity predictions and those obtained using more conventional approaches to the ampacity assessment showed that the CNP estimated ampacity limits were non-conservative. In the case of the conduits, the licensee estimated ampacity limits including derating for the fire barrier system which were in excess of the tabulated ampacity limits for cables in conduits without a fire barrier as set forth in the NBC tables, even given the most generous interpretation of the conduit loadings (only a single cable per conduit with no more than three conductors) .

These results indicate that the subject thermal model may be generating unrealistic and non-conservative estimates of actual cable ampacity limits. The licensee is requested to address these discrepancies.

AEP:NRC:0692DL Attachment 1 Page 13 of 21

Response

A nominal comparison between CNP modelled ampacities, FLA and the tabulated ampacity limits for cables in conduits without a fire barrier, as set forth in the IPCEA/NEC tables, is provided in a table on page 10 of Attachment S. An inspection of this table indicates that the CNP modelled ampacities and FLA are 'less than the limit values in the tables identified in the request. These ZPCEA and NEC ampacity limits were chosen as they correspond to the triplex and 3TC non-jacketed cables used at CNP for power cable applications. As a result of our modelled ampacities being less than those depicted in national standards, we do not believe that our model is generating non-conservative estimates, therefore no discrepancies are believed to exist.

The ampacities and w/ft values generated by the computer model should not be interpreted as values endorsed by CNP design standards. Rather they are predicted values that would be required for a given fill width, of a particular size cable, to generate the maximum qualified cable temperature (90'C).

Request As a part of the validation process, the licensee should provide a direct comparison of its own modeling results to the results obtained using more conventional ampacity derating approaches.

Response

Given the correlation between our thermal model and the 1983 test results (discussed in section 2.3.2, with supporting calculations provided in Attachment 2), we do not believe that using more conventional ampacity derating approaches (for raceways enclosed in a thermal barrier) would prove to be useful.

The ampacities and w/ft values generated by the computer model should not be interpreted as derating values endorsed by CNP design standards'ather they are predicted values that would be required for a given width, of a particular size cable, to generate the fill maximum qualified cable temperature (90'C) .

AEP:NRC:0692DL Attachment 1 Page 14 of 21

2.4.3 'equest In any future submittal, the licensee should also provide a sufficient base of information (i.e. more detailed descriptions of the physical characteristics of each system, and the characteristics of the installed fire barrier system) regarding specific applications.

Response

We agree that a more sufficient base of information should have been previously provided. In this submittal, Attachment 5 provides base information on the physical characteristics of each raceway system considered in this derating analysis. This information includes number of cables per tray, size of cables, cable material, FLA, and rating of fire barrier.

2.4.4 Request The example results for conduits predicted the exact same ampacity limits down to'four significant figures (25.85A) for a 3/C gl2AWG cable in both a l/2" conduit (cable 8026R) and a 1" conduit (cable 8505R for example). While the ampacity tables would not distinguish between these two cases, given the differences in the physical configurations, the thermal model certainly should provide different results. This licensee is requested to identify the source of, and resolve, this discrepancy.

Response

The noted discrepancy was attributed to the physical parameters used to model the 1/2" conduit. Provided in Attachment 5 are the ampacities of the A'.;. pendix R conduits as they are reflected in the latest revision of the Appendix R conduit ampacity calculations. As noted in the request, a difference does exist between the modelled ampacities for a 3/C N12AWG cable in a l/2" conduit (24.38 amperes) and a 1" conduit (26.01 amperes) .

AEP:NRC:0692DL Attachment 1 Page 15 of 21

Reques t The full load amperes (FLA) for the equipment as shown appears low.

Motor Voltage FLA FLA Per NEC Table 430-150 2hp 460 V 2.6 3.4 3hp 460 V 3.8 4.8 15hp 460 V 16 21 20hp 460 V 20 27 Provide the basis for the full load current projections.

The nameplate FLA which is at rated voltage and rated load is acceptable provided the loads are not operating at an overload condition or at a service factor greater than one and the rated voltage is maintained at the load terminals. Provide a discussion about the impact of overload conditions, the service factor of the load and the voltage availability at the load terminals given the stated ampacity derating margins.

Response

The identification of the ampacities, as outlined in NEC Table 430-150, is correct for a distribution voltage of 480 (nominal), however the distribution voltage at CNP is 600 (nominal). Listed below are the same horsepower values and a comparison of the ampere values used vs. NEC Table 430-150.

Motor Voltage FLA FLA Per NEC Table 430-150 2hp 575 V 2.6 2.7 3hp 575 V 3.8 3.9 15hp 575 V 16 17 20hp 575 V 20 22 The small differences between the FLA used and Table 430-150 of the NEC can be attributed to the actual nameplate ampacity. We do not design motor installations to operate the motor either in an overload condition or into the service factor. Cables are sized to 125% of their FLA to account for any short term overload or low voltage condition.

AEP:NRC:0692DL Attachment 1 Page 16 of 21

I I>>

Reques t The allowable ampacity as calculated for g12AWG in Appendix R trays is extremely high. ICEA Standard P 440, "Ampacity of Cables in Open-Top Cable Trays'llows only 15 A (maximum) for 1. 0" depth of f ill and cable diameter of 0.49". The cable used in this calculation has a diameter of 0.32". For 0..32" diameter cable, the allowed ampacity per ICEA Standard P-54-440 will be (0.32/0.49) x 15 = 9.79 amps. This amperes would be reduced further due to fire wrap materi.'al (Thermo-Lag).

Response

The prorating of ampacities, using the ICEA derating tables, for different fill depths as well as different cable diameters cannot be applied in direct proportion as identified in the request.

For example, per section 2.2 of ICEA-54-440 standard, the total number of gl2 AWG installed cables for a 12" wide tray with 1" fill will be:

1 x 12 n

dXd for a 0.49" diameter cable n= 49 cables for a 0.32" diameter cable n= 117 cables However, per AEP design guidelines, only one layer of power cables are placed in a tray up to a maximum 75%

width of the tray, therefore the maximum number of cables installed for the same scenario above would be:

12 d X 1.33 for a 0.49" diameter cable n= 18 cables for a 0.32" diameter cable n= 28 cables As shown, CNP design guidelines limit the loading to less than 28/117 or 24% for the example presented in the request, therefore the proportional conversion suggested is not appropriate.

AEP:NRC:0692DL Attachment 1 Page 17 of 21

For comparison purposes, a graphical representation using ICEA-54-440 table 3.6, "Cable Ampacity Data For a 512 AWG Cable", is shown in Attachment 6. The plot is projected to accommodate CNP design for a 1/2" tray depicts the projected ampacity for 1/2" tray fill.fill The plot to be approximately 20.5 amperes. CNP design guidelines applied to this configuration result in a more conservative loading as they allow a maximum design ampacity of 15 amperes for a fully loaded tray (75% of its width). Therefore we believe that our design standards for a tray of this configuration are not extremely high as stated.

The ampacities and w/ft values generated by the computer model should not be interpreted as derating values endorsed by our design standards. Rather they are predicted values that would be required for a given width, of a particular size cable, to generate the fill maximum qualified cable temperature (90'C) .

Reques t Provide a comparison of the calculated allowable ampacity for Appendix R trays versus the allowed ampacity without the Thermo-Lag as published in ICEA P-54-440 for ~o en-to

~tra considering cable diameter and depth of adjustments. The staff believes that the calculated fill ampacity for wrapped trays must be less than that obtained from ICEA Standard P-54-440. The licensee should provide adequate justification for ampacity values exceeding ICEA Standard P-54-440.

Response

For each tray, Attachment 5 provides a comparison of FLA, modelled ampacity and the allowed ampacity without the Thermo-Lag as published in ICEA P-54-440 for open-top tray (considering cable diameter and depth of adjustments).

fill This attachment also lists the ampacity derat'ng margin available of each cable within these trays as the difference between FLA and ICEA ampacities as a percentage of the ICEA ampacity (~ margin) . In all cases, the FLA and the modelled ampacity were found to be less than the adjusted allowable ICEA amoacities.

AEP:NRC 0692DL Attachment 1 Page 18 of 21

The ampacities and w/ft values generated by the computer model should not be interpreted as derating values endorsed by CNP design standards. Rather. they are predicted width, of values a

that would particular be size required cable, for a given to fill generate the maximum qualified cable temperature (90'C) .

The open tray ampacity values listed in Attachment 5 were adjusted using equation 9 and figure 4 from the Stolpe paper (70-TP 557-PWR). This paper is the basis for the ICEA P-54-440 ampacity tables. The ICEA ampacity calculations were developed using a minimal 10%

value (the lower limit of the plot contained in Stolpe fill paper, figure 4), with adjustments made to reflect actual tray fill conditions. The actual fill for all trays except one (1AI-P2) is less than 10'-., however a 10'; ICEA fill value was used for most cases as a conservative comparison.

All trays at CNP are 12" wide x, 6" deep and are installed horizontally as well as vertically. Each tray is individually wrapped with 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> rated Thermo-Lag except three trays (1AI-P1, 1AI-P2 and 1AI-P4) which are wrapped with an adjacent control tray (side by side proximity) in a common enclosure. These adjacent control trays do not contribute significant heat loads. On the contrary, they significantly increase surface area for heat dissipation (CNP pcwer cable trays are ventilated).

The following is a per t=ay discussion on how the ICEA ampacity limits were adjusted cable diameter and depth of fill(if adjusted at all) for Tray ¹ 1AI-P1 The calculated allowable ampacities for all cal"es in the tray are found to be lower than the calculated ICEA allowed ampacities. The actual tray fill is only 3.95';,

which provides additional margin for ICEA calculated ampacities.

Tray ¹1AI-P2 The calculated allowable ampacities for all cables in the tray are found to be lower than the calculated ICEA allowed ampacities.

AEP.NRC:0692DL Attachment 1 Page 19 of 21

Tray ¹ 1AI-P4 The calculated allowable ampacities for all cables in the tray are found to be lower than the calculated ICEA allowed ampacities. This particular tray carries three (3) cables only. Two cables, size 3TC ¹12 CU, carry a connected load of 0.4 amperes each and the third cable, 3TC¹ 6AL, is used for a welding receptacle circuit with a switch rating of 60 amperes. Connected load for the ¹ 6 AL cable is much smaller and non- continuous type.

Purther, the actual tray Therefore, a 4'-. fill fill is found to be only 0.95%.

criterion is used in calculating the ICEA ampacities for 3TC ¹12 CU cable.

Tray ¹ 2AZ-P3 The calculated allowable ampacities for all cables in the tray are found to be lower than the ICEA allowed ampacities. The ICEA ampacities are based on 9% tray fill. Although motor operated valve load is considered in the analysis, this load does not contribute to any heat load with respect to the long-time cable degrading issue due to short stroke time for valve operation.

Tray ¹ 1AZ-PS The calculated allowable ampacities for all cables in the tray are found to be lower than the ICEA allowed ampacities.

therefore, a 4-.

The actual fill fill is found to be 2.62%,

criterion is used in calculating the ICEA ampacities for 3TC ¹12 CU cable. Although motor operated valve load is considered in the analysis, this load does not contribute to any heat load with respect to the long-time cable derating issue due to short stroke time for valve operation.

Tray ¹ 1AZ-P9 The calculated allowable ampacities for all cables .'n the tray are found to be lower than the ICEA allowed ampacities. The actual Therefore, a 4'-. fill fill is found to be 3.60%.

criterion is used in calculating the ICEA ampacities for 3TC ¹12 CU cable.

Tray ¹ 1A-P20 The calculated allowable ampacities for all cables in the tray are found to be lower than the ICEA allowed ampacities. The ICEA amprcities are based on 9-. trav fill except as noted.

AEP:NRC:0692DL Attachment 1 Page 20 of 21

Tray ¹ 2AZ-P10 The calculated allowable ampacities for all cables in the tray are found to be lower than the ICEA allowed ampacities.

Tray ¹ 2A-P2 The calculated allowable ampacities for all cables in the tray are found to be lower" than the ICEA allowed ampacities. The actual Therefore, a 4% fill fill is found to be 2.48%.

criterion is used in calculating the ICEA allowed ampacities for 3TC ¹12 CU 'cable.

Request Provide a comparison of calculated allowed ampacity in Appendix R conduit versus allowed ampacity in conduit as published in ICEA Standard P-46-426 (including factors for the number of conductors, grouping factors for cables in exposed or enclosed conduit in air, etc.). Provide sufficient details (cable type, cable diameter, number of conductors, etc.) to conduit size, percent assess fill, temperature, ampacity rating for the example cases.

The staff believes that the calculated ampacity for wrapped conduits must be less than that obtained from ICEA Standard P-46-426. The licensee should provide adequate justification for ampacity values exceeding ICEA Standard P-46-426.

Response

A nominal comparison between FLA, modelled ampacities and ampacity limits for cables in conduits, as set forth in IPCEA P-46-426 and the NEC tables, is tabulated in . This table includes cable type, cable diame"er, number of conductors and conduit size. An inspection of this table indicates that the FLA and modelled ampacities are below the limit values provided in IPCEA P-46-426 and the NEC. These IPCEA and NEC ampacity limits were chosen as they correspond to the triplex and 3TC non-jacketed cables used at CNP for power cable applications.

The ampacities and w/ft values generated by the computer model should not be interpreted as values endorsed by CNP design standards. Rather they are predicted values that would be required for a given fill width, of a particular size cable, to generate the maximum qualif ied cable temperature (90'C).2 AEP:NRC:0692DL Attachment 1 Page 21 of 21

ATTACHMENT 2 TO AEP:NRC:0692DL TABLE DEPICTING CORRELATION BETWEEN THE PREDICTED AND MEASURED AMPACITIES

~atettt;<tint< t<t an <mrt tt<e eerifiraltna nt'he NP Thermal Mori i a lied o tra Test Cable 'I'ype Test No. of,Runs Highest Predicted Predicted (Fill (l)launctcr) Loading (Contributing Measured Ampacity Watts/Ft Width) (A) Width) Temperature (A) (w/ft)

('C) 3TC¹12CU (0.32") 3.8 7 (2.24") 45.6 6.96 (4.12") 3TC¹12CU (0.32") 20.0 3 (0.96") 59.7 13.41 13.01 3TC¹2AL (0.92") 60.0 1 (0.92") 55.7 49.58 9.87

~ Predicted values are based on thc highest mcasurcd tcmpcraturc as the conductor temperature. Predicted values are also based on thc fill width being comprised totally of the respective cable type.

Calculated heat generated pcr conductor by rcsistivc heating = ¹ of conductors x I x R~,

where I = conncctcd load (A)

R~ = AC rcsistancc (0/ft)

Applied to thc modelling of Test 1 using thc prcdictcd ampacitics, the modelled heat generated is:

3TC¹12CU = 21 x 6.96" x '~77.SE-5 = 1.81 AV/ft 3TC¹12CU = 9 x 13.41 x 184.27E-5 = 2.98 W/ft 3TC¹2AL 3 x 49.58" x 29.84E-5 = 2.2 iV/ft Total modelled heat gcncratcd = 6.99 KV/ft Applied to thc actual loading in Test 1 above, thc total actual heat generated is:

3TC¹12CU = 21 x 3.8" x 177.8E-5 = 0.5391 W/ft 3TC¹12CU = 9 x 202 x 184.27E-5 = 6.634 W/ft 3TC¹2AL = 3 x 60 x 29.84E-5 = 3.223 W/ft.

Total actual heat gcncratcd = 10.4 W/ft Resistances have been adjusted to corrcspond to their rcspcctive measured temperatures Usted above A comparison of thc predicted heat gcncratctl (6.99 W/ft) and thc actual heat generated (10.4 W/ft) for the given test case above dcmonstratcs that thc CNP thermal modelling approach is conservative. This is considcrcd conservative since this cstablishcs thc "limit." I'or which other identical raceways can be compared to for acccptancc (i.c. - those identical candidate raceways must have a total heat value less than this limit thcrcby ensuring that thc heat gcncratcd is less than thc heat corresponding to a known tcmpcraturc).

AEP:NRC:0692DL Attachment 2 Page 1 of 4

'The predicted values listed in Test 1 have bccn gcncratcd from the computer model using the following input:

INPUTS 3TC¹12CU 3TC¹12CU 3TC¹2AL

¹ of cables* 12.875 12.875

¹ of thermal layers o.d. of layer I (inches) 13.34 13.34 thickness of layer I (inches) 0.5 0.5 0.5 dead alf space outside la)'cl I cmmisivity of layer I 0.9 0.9 0.9 thermal resistivity of layer I ('C cm/lV) 578.03 578.03 578.03 conductor tcmpcrature ('C) 45.6 59.7 55.7 ambient tcmpcraturc ('C) 40 electrical resistivity of conductor (circ mil 0/ft Qn20'C) 10.371 10371 17.002 inferred tcmpcraturc ot'zero rcsistancc ol'ond.('C) 234.5 228.1 linc to linc voltage (1<V) 0.6 0.6 0.6 specific inductive capacitance ol'nsulation 2.3 2.3 2.3 power factor of insulation 0.035 0.035 0.035 thickness of jacket (inches) thermal resistance ol'acket ('C cm/lV)

¹ of conductors pcr cable circular inch area of contluctor 0.00653 0.00653 0.06636 conductor diamctcr (inches) 0.092 0.092 0.292 insulation diameter (inches) 0.1488 0.1488 0.4279

'thermal resistivity ol'nsulation ('C cm/lV) 450 450 450 AC/DC ratio emmisivity of cable surface diamctcr of cable (inches) 0.32 0.32 0.92

~

¹ of cables = lill width + cable diamctcr AEP:NRC:0692DL Attachment 2 Page 2 of 4

I~

The predicted values listed in Test I 5 have bccn

~

~t I gcncratcd from thc computer model using the following I~

input:

INPUTS 3TC¹2AL

¹ of cables

¹ of thermal layers o.d. of layer I (inches) 4.5/6 thickness of layer I (inches) 0.237/0.5 dead air space outside layer I 0.25/1 cmmisivity of layer I 0.055/0.9 thermal resistivity of iayct I ('C cm/lV) 2.2/578.03 conductor tempcraturc (' 65 ambient tcmpcraturc 40 resistivity of comluctor (circ mil 0/ft Qn20'C)

('C,'lcctrical 17.002 inferred tcmpcraturc of zero rcsistancc ol'ond.('C) 228.1 linc to linc voltage (KV) specific inductive capacitance of insulation 2.3 power factor of insulation 0.035 thickness of jacket (inches) 0.02 thermal resistance of j acket {'C cm/~V) 450

¹ of conductors pcr cable circular inch area of conductor 0.06636 conductor diamctcr (inches) 0.292 insulation diamctcr (inches) 0.530 thermal resistivity of insulation ('C cm/lV) 450 AC/DC ratio cmmisivity of cable surface diameter of cable (inches) 1.14 AEP:NRC:0692DL Attachment 2 Page 4 of 4

4 ~ t ATTACHMENT 3 TO AEP:NRC:0692DL MODEL COMPUTER CODE

~>

1~0 REM'**4'************************~************************jq 20 REM ****** DXSPLAY PROGRAM DESCRXPTION AND PROMPT USER ***

30 REM ***+** FOR INPUTS. ***

40 REM *4'*4**************************************************

CLS INPUT Q9$

80 IF Q9$ =<<Y<< THEN 580 90 PRXNT <<FXRE BARRIER AMPACITY DERATING-IX (FBAD2)<<

100 PRXNT <<DO YOU NEED HELPS (Y OR N)<<

110 INPUT Q18 120 XF Q1$ =<<Y<< THEN 140 130 GOTO 620 140 PRXNT 150 PRINT "THIS PROGRAM IS DESIGNED TO CALCULATE THE AMPACXTY OF" 160 PRXNT <<CABLES IN RACEWAY ENCLOSED IN FXRE BARRXER MATERIAL 170 PRXNT " THE MODEL USED TO DEVELOP THIS PROGRAM APPROXIMATES" 180 PRXNT " THE THERMAL CHARACTERXSTICS OF VARXOUS RACEWAY AND<<

190 PRXNT " FIRE BARRXER CONFIGURATIONS BY USXNG THE EQUATXONS OF<<

200 PRINT " HEAT FLOW THROUGH CYLINDRICAL SURFACES DEVELOPED" 210 PRXNT " BY NEHER AND MCGRATH IN THEXR 1957 AXEE PAPER."

220 PRXNT 230 PRXNT <<SXNCE HEAT TRANSFER IS LARGELY DEPENDENT ON THE SURFACE 240 PRXNT AREA OF THE TRANSFER MEDIUMS THE EQUXVALENT DIAMETER 250 PRXNT " OF NON-CIRCULAR RACEWAY (X.E., TRAY AND FIRE BARRXER<<

260 PRINT " SYSTEMS SHOULD BE DETERMINED BY USXNG THE PERIMETER 270 PRINT " NOT THE X-SECTIONAL AREA OF THE ENCLOSING MATERIAL."

280 PRXNT " IN OTHER WORDS THE EQUIVALENT DIAMETER OF A 12 INCH BY 290 PRINT " 6 XNCH TRAY SHOULD BE 2x(H+W)/3.14 OR 11.46 XNCHES.<<

300 PRINT RINT "PLEASE NOTE THAT THIS PROGRAM IS VALID ONLY IF TRAY FILL" RXNT "DOES NOT VXOLATE THE AEP'S CRXTERXA FOR POWER TRAY (X.E.-<<

33 PRINT <<754 OF TRAY WIDTH AND 1 LAYER DEEP)."

340 PRINT 350 PRXNT "WHEN ENTERING N, THE NUMBER OF HEAT TRANSFER LAYERS 360 PRINT " DO NOT XNCLUDE THE CABLE INSULATXON OR JACKET AS A 370 PRXNT " LAYER. THXS WILL BE DONE BY THE PROGRAM."

380 PRINT 390 PRINT <<DO YOU NEED HELP ENTERXNG THE DATA+ (Y OR N)<<

400 INPUT Q29 410 IF Q2$ <<Y<< THEN 430 420 GOTO 620 430 PRINT 440 PRINT 450 PRXNT "DATA SHALL BE INDICATED AS BELOW<<

460 PRXNT 470 PRINT <<DO YOU WANT A PRINT OUT OF DEFXNXTXONS. (Y OR N)<<

480 INPUT Q4$

490 XF Q4$ =<<Y<< THEN 510 500 GOTO 530 510 N=1 520 GOTO 1890 530 PRINT 540 PRINT <<DO YOU WANT TO ENTER DATA'Y OR N)<<

550 INPUT Q5$

5 Q5$ =<<Y<< THEN 1880 5 TO 620 58 F Q9$ <><<Y<< THEN 620 AEP:NRC:0692DL 590 PRXNT "OUTPUT?" Attachment 3 600 XNPUT Q3$ Page 1 of 5

'610 GOTO 640 6'20 PRINT "DO YOU WANT A LONG FORM OF THE OUTPUT? (Y OR N)"

630 INPUT Q3$

640 PRXNT PRINT i>ENTER THE TYPE OF CABLE TO BE RUN INPUT B$

PRXNT 680 PRINT XNPUT Y9 AND Z9~ THE LXMXTS OF CABLES 690 INPUT Y9 700 XNPUT Z9 71P REM A****************************************************A*

720 REM ********* READS DATA XN *******************************

73P REM *******************************************************

740 DXM D9 (5), T (5) g S (5) g E9 (5) P9 (5) p g CP (5) g M (5) g A9 (5) g Z8 (5) g Y8 (5) g Q99 (5) I9 (20) g 760 READ N 770 FOR X=1 TO N 780 READ D9 (I) T(I) gS(I) gE9 (I) gP9 (I) g 790 Cl=C1+2 800 XF S(X)>0 THEN 820 810 Cl=cl-1 820 NEXT I 830 READ Tlg T2gP~ TpgV/ El Fl 840 READ T5,P5 850 READ Nl ~ Cg DO g Dl g Pl g Ag E5 J D5 860 XF Q9$ ii Yii THEN 880 870 IF Q3$ ="Y" THEN 1890 880 Cl=C1+3 890 IF T5>0 THEN 910 900 Cl=cl-1 T3=(Tl-T2)/Cl Cl=p 9 REM ***********DC RESXSTANCE 940 R=l.02*P/C*(TO+Tl)/(TO+20) 950 REM ***********DIELECTRIC LOSS 960 XZZ=LOG(D1/DO)/LOG(10) 970 W=.00276*(V/1.73205)"2*El*F1/XZZ 980 IJK=O 990 FOR J=Y9 TO Z9 1000 XF IJK=1 THEN 1750 1010 Q=l 1020 REM ***********NUMBER OF CONDUCTORS 1030 N3=J*N1 1040 REM ***********THERMAL RESISTANCE OF INSULATXON 1050 R1=.012*Pl*LOG(Dl/DO)/LOG(10) 1060 C2=1 1070 IF T5=0 THEN 1110 1080 REM ************************THERMAL RESISTANCE OF JACKET 1090 C5=.0104*P5*N1*T5/(D5-T5) 1100 C2=C2+1 1110 C5=0 1120 REM ************************FILL WIDTH 1130 D5=D5*J 1140 REM **************************AXRSPACE 1150 S5=D9 (1) -T(1) -D5 1 M5=T1- (C2*T3+T3/2) 1 C2=C2+2 1 REM **************************THERMAL RESXSTANCE OF AIRSPACE 1190 A5=N3/(.092*D5".75*T3".25/(1.39+D5/(D5+S5))+.0213/(LOG((D5+55)/D5)/LOG(10)

)+.102*D5*E5*(1+.0167*M5))

Attachment 3 Page 2 of 5

f200 REM +************THERMAL RESISTANCE OF XNSUL, JACKET AND AIRSPACE 1210 RO=R1+C5+A5 1220 REM ***************THERMAL LAYER RESXSTANCES 1230 FOR X=1 TO N CP (I) =. 0104*P9 (I) *N3*T(X)/ (D9 (I) -T(I) )

NEXT I

• • • • • • • • • • • • • • • • THERMAL 0 REM RESISTANCE OF AIRSPACE BETWEEN THERMAL LAYERS 1270 IF N<2 THEN 1390 1280 FOR I=1 TO N-1 1290 XF S (I) >0 THEN 1320 1300 C2=C2+1 1310 GOTO 1380 1320 E=l/ (1/E9 (I) +D9 (I) /D9 (1+I) *(1/E9 (I+1) -1) )

1330 IF Q>1 THEN 1360 1340 M(I)=Tl-(C2*T3+T3/2) 1350 Q99 (I) =T3 1360 A9 (I) =N3/ (. 092*D9 (I) 75*Q99 (I) 25/ (1 39+D9 (I) / (D9 (I) +S (I) ) ) +

~ ~ 0213/LOG( (D9 (I)+S (I) ) /D9 (I) ) /LOG (10) +. 102*D9 (I) *E*(1+.0167*M(X) ) )

1370 C2=C2+2 1380 NEXT I 1390 IF Q>l THEN 1420 1400 M(N)=T1-(C2*T3+T3/2) 1410 Q99 (N) =T3 1420 A9 (N) =15 ~ 6*N3/ (D9 (N) *( (Q99 (N) /D9 (N) ) ~ 25+1 6*E9 (N) *(1+ 0167*M(N) )

~ ~ ) )

1430 REM *************SUM ALL RESISTANCES 1440 FOR X=1 TO N 1450 R O=RO+CP (I) +A9 (I) 1460 N EXT I 1470 R EM *************CALCULATE RESULTS 14 D =W*(RO-Rl/2)

I9 =SQR((T1 (T2+D) /(R*A*RO)) *1000 (Q) )

0 Wl=N3*I9 (Q) "2*R*A/1000000!

1510 IF Q=l THEN 153 0 1520 XF ABS ( (I9 (Q) -X9 (Q-l) ) /X9 (Q) ) <. 000001 THEN 1690 153.0 T9=T1-(Rl+C5)*W1/N3 1540 T8=T1-(Rl+C5+A5)*W1/N3 1550 T3=T9-T8 1560 KS=O 1570 K9=0 1580 FOR I=1 TO N 1590 K9=KS+CP(I) 1600 KS=K9+A9 (I) 1610 Z8(I)=T1-(Rl+C5+A5+K9)*W1/N3 1620 Y8(I)=T1-(Rl+C5+A5+KS)*W1/N3 1630 M(X) = (ZS (I) +Y8 (I) ) /2 1640 Q99 (I) =ZS (I) -YS (I) 1650 NEXT I 1660 M5=(T9+TS)/2 1670 Q=Q+1 1680 GOTO 1190 1690 Xl=I9 (Q) 1700 F Q3$ ="Y" THEN 2170 1710 PRXNT 1720 CLS 1730 PRINT 1 PRXNT 1 PRINT "NUMBER OF CABLES=" J 17 PRINT "NUMBER OF CONDUCTORS=",N3 1770 PRINT ALLOWABLE AMPACITY=" Xl AEP:NRC:0692DL 1780 PRXNT "WATTS PER FOOT OF RACEWAY=" Wl

Attachment:

3 page 3 of 5

4 Y790 PRINT 1800 LPRINT 1810 PRINT 1820 PRXNT 0 D5=D5/J C2=0 0 RO=O

.1860 NEXT J 1870 LIST 2410-2450 1880 STOP 1890 PRINT N, "=N, THE NUMBER OF CABLE ENCLOSURE LAYERS" 1900 FOR I=1 TO N 1910 PRXNT D9(X),"=EQUXVALENT OUTSXDE DIAMETER OF LAYER I" I"

~

1920 PRINT T(X),"=T(I), THICKNESS OF LAYER 1930 PRINT S(I)I S(X)I DEAD AXR SPACE X9 (1 FOR AMBIENT 1940 PRINT E9 (I) r E9 (I) r EMISSXVITY OF SURFACE I I" 1950 PRXNT Pb(I) ".=P9(X), THERMAL RESISTXVXTY OF LAYER 1960 NEXT I 1970 I PR NT T 1 r T 1 ~ CONDUCTOR TEMPERATURE 1980 PRINT T2 "=T2, AMBXENT TEMPERATURE" 1990 PRINT P,"=P, ELECTRICAL RESISTIVXTY OF CONDUCTOR" 2000 PRINT TO,"=TO, INFERRED TEMP OF ZERO RESISTANCE OF CONDUCTOR" 2010 PRINT V,"=V, LINE TO LINE VOLTAGE IN KV" 2020 PRI NT E 1 r E 1 r SPECI FXC INDUCTXVE CAPACITANCE OF INSULATION 2030 PRINT Fl,"=F1, POWER FACTOR OF INSULATION" 2040 PRINT T5 T5r THICKNESS OF JACKET 2050 PRXNT P5,"=P5, THERMAL RESXSTANCE OF JACKET" 2060 PRINT Nlr =Nlr NUMBER OF CONDUCTORS PER CABLE 2070 PRINT C,"=C, CXRCULAR INCH AREA OF CONDUCTOR" 20 0 PRINT DO >> DOr THE CONDUCTOR DIAMETERrr PRINT Dlr Dlr THE INSULATION DIAMETER PRINT Plirr-Plr THERMAL RESXSTIVITY OF INSULATION 2110 PRINT AI Ar THE AC(DC RATIO 2120 PRINT E5rrr E5~ EMXSSXVXTY OF THE CABLE SURFACE 2130 PRINT D5,"=D5, DXAMETER OF THE CABLE" 2140 PRXNT 2150 IF Q3$ ="Y" THEN 880 2160 GOTO 530 2170 PRINT R,"=R, DC RESXSTANCE 2180 PRINT W,"=W, DIELECTRXC LOSSES" 2190 PRINT Dr Dg DELTA T DXELECTRIC 2200 PRINT Rl,"=Rl, THERMAL RESXSTANCE OF XNSULATION" 2210 PRINT C5,"=C5, THERMAL RESXSTANCE OF JACKET" 2220 PRINT A5,"=A5, THERMAL RESXSTANCE FROM CABLE TO RACEWAY" 2230 PRINT M5r M5r MEAN TEMP OF AIR IN RACEWAY 2240 PRINT T3rrr-T3r TEMP AT SURFACE OF CABLE GROUP 2250 PRXNT T9r T9I TEMP AT SURFACE OF CABLE GROUP

~

2260 PRINT T8,"=T8, TEMP. AT INNER SURFACE OF RACEWAY" 2270 FOR X=1 TO N 2280 I I I PRINT CP ( ) I CP ( ) r THERMAL RES STANCE OF LAYER I I" 2290 PRXNT A9(I),"=A9(X), THERMAL RESISTANCE OF AXR SPACE 2300 PRINT M(X),"=M(X), MEAN TEMP. OF AIR SPACE I" 2310 PRINT Q99(I),"=Q99(I), TEMP. DROP THROUGH AIR SPACE X" 2320 PRINT Z8(I),"=Z8(I), TEMP. AT OUTER SURFACE OF LAYER I" 2330 I I PRINT Y8 ( ) r Y8 ( ) r OUTER TEMP OF AIR SPACE I 2 EXT I 2 RXNT ROirr-ROi TOTAL THERMAL RESISTANCE 23 PRINT AEP:NRC:0692DL 2370 PRXNT Attachment 3 2380 IJK=1 Page 4 of 5

I 2390 GOTO 990 2400 REM ***************DATA SECTION 0 DATA 1 DATA 13 ~ 34 I 0 5 ~ 1 I 0 9 I 578 03

~

0 DATA 90g40I 10371~234 ~ 5~06/2 3 I 0035 2440 DATA 0, 0 2450 DATA 3 I 0 00653 I 0 092I 0 ~ 1488 I 450I 1 I 1I 0 32

~

2460 END AEP:NRC:0692DL Attachment 3 Page 5 of 5