ML19210D968

Forwards Calculations Re Ampacity of Power Cable Trays Which Disagree W/Fsar Table 8.3-18.OL Should Not Be Granted Until Util Determines Ampacity of Cable Trays

ML19210D968
Person / Time
Site:	Zimmer
Issue date:	11/09/1979
From:	Gillman D MIAMI VALLEY POWER PROJECT
To:	Atomic Safety and Licensing Board Panel
Shared Package
ML19210D967	List: ML19210D966 ML19210D968
References
NUDOCS 7911290104
Download: ML19210D968 (4)

Text

.

November 9, 1979 Chai=,

.,. ,, an, Atenic Safety and Licensing 3 card Panel

<2 4%7 gs

p .. $ v e

' hy,I

~ '

$ '$'ing $E, D.C. 20555 l' q q).ap q

Dear Sir:

g&

wf The enclosed calculations have made me suspect of Table 8 3-18 of the Zimmer Power Station, Unit 1 FSAR. These calculations are based on ICEA P-54-4 0. Furthermore, there will be significant lengths of pcwer cable trays which will be covered by fire retardant insulation thus creating a differential of slightly greater heat accumulation within the power cable trays.

This would not ordinarily be a cencern if Sargeant and Lundy (architect-engineer for ZPS-1) had included the operating amperage of each cable at ZPS-1 on the cable pull-card tabulation which is computer assisted information. The lack of a central information bank which could easily determine the ampacity of every power cable tray at ZPS-1 is negligence. The cable routing pull-cards could have easily had the additional information of operating amperage load.

Given the lack of centralized cable tray ampacity calculating ability, the design specifications of ZPS-1 FSAR Table 8 3-18 deserve whatever attentien available.

I do net believe that.in light of the San Onofre fires and the information handlirg capacity of modern ecmputers, any nuclear power station should be granted an operating license without knowledge of the ampacity of every pcwer cable tray in that station.

Sincere'y, l Y' Loug G4 '7-$n 772 Red Bud Ave.

Cincinnati, CH 45229 1434 113 7911290\ M

Calculations Cc= paring Zi:mer Power Station Unit i FSAR Table 8 3-18 with ICEA-NEMA Standards Publication (ICEA P-54 440/ NEMA WC 51-1975)

A=pacities in Open-top Cable Trays Section 8 3 313 of the ZPS-1 FSAR states an allowable cross sectional area of cables to be no = ore than 60% of the cross sectional area of the cable tray.

All of these calculations take the conservative figure of 55C of a cable tray of di=ensiens 6 inches by 24 inches. 6"x24"x0 55= 79 2 sq. in.

For a given cable size the area of the cable is calculated from the given diameter by finding the radius, squaring and multiplying by pi. This cable area is then divided into the 55< area figure, or 79 2 sq. in. This ce=putation gives the nunber of cables comprising a 554 fill. The number of cables is u. sed in the equation on page i of the ICEA Publication P-54 440 to arrive at what this publication calls the " calculated depth of cables in trays". This number becomes a colunn heading in the use of the tables in this publication. The P-54 440 a=pacity is compared with the power cable ampacities in Table 8 3-18 as a percent ratio of their difference over the P-54 440 a=pacity. This percentage is then interpreted as the a=ount of underrating or overrating by the utility. The clai= by the utility that it has derated its a=pacities does not agree with the calculatiens which are based en open-top cable trays which have the advantage of circulating air to cool the cables. ICEA P-54 440 is based on the work cf J. Stolpe who first investigated cable tray ampacities in response to the San Cnofre cable hi tray fires since he was employed by the utility that cwns San Onofre. Stolpe's original calculations appeared in the " San Onofre Nuclear Generating Statien, Unit 1, Report en Cable Failures,1968" before he published his paper, L .:.2. Paper 70 TP 557-PWR, "A=pacities for Cables in Rande=ly Filled Trays."

6A'73, ikv, t /c -

0.D. (everall diameter of cable)= 0 31 in. (data from Anaconda) r= .155 in.

79 2 sq. in./(pi( .1551n.)2)= 1049 cables Calculated Depth of Cables in Trays (CDCT)=10E9(.311n)2/24 = 4.2 in.

Table 10 (P-54 h40): 18 amp.

FSAo TAPLE 8 3-18: 21 amp (21-18)/18 = 164 over-rated 6AWG, ikv, 3/c 0.D.= 0.54 in. (data fras Anixter-Cleveland) r= 0.42 in.

79 2 sq. in./(pi(.42in.)2)= 142 cables CDCT = 142( 841n.)2/24 in. = 4.2 in.

' Table 12 (P-54 Ah0): 28 a=p.

FSAR Table 8 3-18: 30 a=p.

(30-23)/28 = 76 cver-rated EAWG, ikv, ?/c 0.D. = .99 in. ( Anixter-Cleveland) r = .495 in.

79 W =2102( sq. in./(pi(2/241n.

.99tn) - 4.16 in..495in.)2) = 102 cables Table 9 (?-54 N ): 39 a=c.

FSAR table 3 3-18: 43 amp". l4)4 l}k 43-39/39= 1C4 over-rated

Page 3 4/0 AWG, Slet, 1/c 0.D. - 1 99 in. (Anixter-Cleveland) r .995 in.

79 2 sq.in./(pi( .905 in.)2) - 25 cables CDCT - 25(1991n.)2/24 in. - 4 12 in.

Table 16 (P-54-Ah0): 169 amp.

FSAR Table 8 3-1S: 204 amp.

204-169/169 - 2d over-rated 250 MC:t.11ei.1/e O.D. .77 in. (Anaconda) r .385 in.

79 2 sq.in./(pi(.3 CDCT-17C(.771n.)[5in.)2)-170

/24in. - 4 19 in. cables

• Table 10 (P-54 4h0): 136 amp.

FSAR Table 8 3-18: 159 amp.

159-136/136 = 1M over-rated 250 mci, tier, 9/c O.D. - 1 90 ( Anixter-Cleveland) r - 95 in.

79 2 sq.in./(pi(.951n.)2) - 27 cables CDCT - 27(1 90in.)2/24 in. - 4.06 in.

Table 12 (P-54 440): 190 amp.

FSE Table 8 3-18: 212 amo.

212-190/190-11% over-rated 9<0 ':Ct. ikr, 3/c 0.D. = 2 14 in. ( Anixter-Cleveland) r = 1 07 in.

79 2 sq.in./(pi(1 07 in.)2) - 22 cables CDC" - 22(2 14 in.)2/24in.=4.19in.

Table 12 (P-5h ALO): 250 amp.

FSE Table 8 3-18: 278 amp.

278-250/250-11% over-rated Unfortunately, ICEA P-54 440 does not include a column S 4 inch ' calculated depth of cables in trays'.

However, if the reviewer belisves that using a 554 cable tray fill is not conservatire enough, the reviewer is advised to use a 504 (6" x 24" x .50 - 72 sq. in.) criterien.

The reviewer will find that that using a 50% eriterien reduces the ' calculated depth of cables in trays' frem a little more than E inch a to around 3i inches and the same column in the tables (the 3" column) will again be used for 50% tray fill calculaticns, leaving the over-rating percentages for each type of pcwer cable unchanced.

ICEA P-54 hA0 (E!A WC 51-1975) (ICEA-E'A Standards Publication, Ampacities, Cables in Open-top Cable Trays) is avai.!.able frcm: Standards Pablications Editer, National Electrical Manufacturers Association, 2101 L. St., N.W. , Washing cn, D.C. 20037 1434 115

Page 2 2AWG. iki, 3/c 0.D. - 1 14 in. (Anixter-Cleveland) r .57 in.

792sq.in./(pi(.5 CDCT-77(1141n.)}in.)2)-77eables

/24in.-4.16in. ~

Table 12 (P-54 440): 55 an.

FSAR Table 8 3-18: 61 amp.

61-55/55-10% over-rated 1/0 AWG, iki. 1/c 0.D. .541n. ( Anac~via) r= .271n 79 2 sq.in./(pi( .2 CDC-$5(.541n.)}in.)2)-$5

/241n. - 4.19 in. cables Table 10 (P-54 440): 61 a p.

FSAR Table 8 3-18: 72 a=p.

72-61/61-18% over-rated 1/0 AWG, iki, 3/c 0.D.= 1 361n. ( Anixter-Cleveland) r= .681n.

79 2sq.in./(pi( .68 .)2) - 54 cables CDCT-54(1361n.)p/24in.-4.16in.

Table 12 (P-54 kh0): 86 amp.

FSAR Table 8 3-18: 96 amp.

96-86/86=11% over-rated 2/0 AWG, Ski, 3/c 0.D.- 1 70in. (Anixter-Cleveland) r .851n.

79 2 sq.in./(pi(,8 CDCT-34(170in.)}in.)2)=34

/241n. = 4.09 in. cables Table 16 (P-54 440): 108 amp.

FSAR Table 8 3-18: th4 amp.

144-108/108 - 33% over-rated 3/0 AWG, iki, 3/c 0.D. - 1 55 in. (Anixter-Cleveland) r= .775 in.

79 2sq.in./(pi( .7751n.)2) , gg eg31,3 CDCT h1(1 551n.)I/24 in. 4.10 in.

Table 12 (P-54 440): 124 amp.

FSAR Table 8 3-18: 138 anp.

138-124/124 - li$ ever-rated h/0 NelG, i ki, 3/c 0.D. - 1 69 in. (Anixter-Cleveland) r = .8h5 in.

79 2 sq.in./(pi( .8h51n.)2) - 35 cables CDCT - 35(1.691n.)2/241n. - 4.16 in. }434 i}b Table 12 (P-54 kh0): 156 a=p.

FSAR Table 8 3-18: 167 a=p.

167-156/156 - 7% over-rated