ML20195G354
| ML20195G354 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 06/16/1988 |
| From: | Bailey J GEORGIA POWER CO. |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| GN-1459, NUDOCS 8806270306 | |
| Download: ML20195G354 (14) | |
Text
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Geova Powir Company Post Off>cs Box 282 Waynesboro, G;orgia 3083o a
Telephee 404 554-9961 404 724,d114 Southern Company Services, Inc.
Post Office Box 2625 8vmingham, Alabama 35202 re,epaoes as s' ""
Vogtle Project June 16, 1988 U. S. Nuclear Regulatory Commission ATTN:
Document Control Desk File:
X7BC35 Washington, D. C.
20555 Log:
GN-1459 PLANT V0GTLE - UNITS 1 & 2 NRC DOCKETS 50-424, 50-425 OPERATING LICENSE NPF-68, CONSTRUCTION PERMIT CPPR-109 ELECTRICAL SEPARATION CRITERIA
Reference:
Letter GN-1434 from J. A. Bailey to NRC, dated March 14, 1983 Gentlemen:
In the referenced letter, Georgia Power Company informed the NRC of proposed changes to the FSAR establishing reduced separation distances for cable and raceway configurations not previously tested or analyzed.
These reduced separation distances are based on testing conducted by the same laboratory and in accordance with the same criteria as the previous tests conducted in May 1986, and approved in SSER 4.
Attachment A to this letcer provides our written response to your questions which were discussed in the May 25, 1988, telephone conference call on this :;ubject.
These questions concerned worst case orientation, peak temperatures, and insulation resistance.
i Also mentioned were certain minor corrections and clarifications to be made to the proposed FSAR page changes submitted in the referenced letter.
Attachment B to this letter provides these changes, as well as brief explanations or justifications for the changes.
Should you have any further questions, please advise.
Sincerely,
'N-J. A. Bailey Project Licensing Manager JAB /wkl Attachments 8806270306 000616 l
f DR ADOCK 0500 4
u j
File: X7BC35 Log: GN-1459 Page two xc:
NRC Regional Administrator NRC Resident Inspector P.
D. Rice L.
T. Gucwa R.
A. Thomas J.
E. Joiner, Esquire J.
B. Hopkins (2)
G.
Bockhold, Jr.
R.
Goddard, Esquire B.
W. Churchill, Esquire R.
W. McManus Vogtle Project File 1
i
O 4
ATTACHMENT A RESPONSE TO NRC QUESTIONS i
l ATDODENP A Responses to IRC Questions Ibte References to "Attach ents" refer to attachnents to letter GIF1434 dated 14 arch 14,1988 1.
In many cases, the tested configuration involved a fault cable located cnly vertically below the target cables, yet the separation distance criteria allows the cables to be located horizontally at the same distance. Please clarify.
During the selecticn of tie test configuraticns, the project attspted to select arrangments that are tre rest conserva-tive and that would best envelcpe the conditions that could exist in the field. Typically, this resulted in placing the fault cable directly belcw the selected target cables such that the ccovective heat frm the faulted cable would directly inpinge on the target cables. 'Ihis is considered the worst case ccndition and would envelcpe any other target 1.ocation relat.ive to the fault cable at the given separatico distance. This consideration is documented in FSAR Table 8.3.1-4, sheet 1, note b.
2 With regard to Attachent B, page 1, the tested separaticn distance is shown as 3/4" vertical and horizmtal for config-uraticn 1, test 1 (test 1/2). 'Ibe asscx: lated test report (Attachment C) shows that the tested ccnfiguraticn wcs cnly in a vertical directicn. Please clarify.
We believe your concern arises due to the fact that Attach-nent B inadvertently ircluded the wrd "Tested" in t}e fcurth colunn title cn page 1.
The intent of this colven in Attach-nent B is to describe the required separation distance as a result of the test, not to describe the tested condition itself. The columns are correctly titled on Attachrent B, page 2.
3.
With regard to Attachsgt C, test 4/2 has a ccnduit crossing free air cables at a 77 angle. How is this test ecnfiguraticn inplanented in the field?
Field corditions typically have raceways installed in essen-tially perpendicular or parallel configurations. 'Ihe test configuration was selected to envelcre expected variations in therelativeposigionofcablesandraceways. A minimum angle limit of 30 has been inposed as irdicated in FSAR Table 8.3.1-4, paragraph 15. Testing was corducted at 27 to provide nargin beyond specified requirments. Presently, the Constnction Specificatica does tot allcw the use of this relaxed criteria (free air cables tcuching ccrduits) howver, it is available as a basis for Engineering to accept as built conditicos that do not otherwise satisfy the present ccostructicn specification requirenents in X3AR01-E8, Attachment B.
Page 1 of 4
If raceways /cabits wre fouy to exist in the plant at rslative angles its2 than 30, the project would revert back to the separation criteria for cables / raceways that are parallel with each other (e.g. FSAR Table 8.3.1-4, paragraph
- 5).
4.
In Attactinent C, test 4/3 has tarperature neaaurunents indfc-ating that the peak taperature of the fault conduit. (316 F) is lower the peak tenperature of the fire air target cable (332
) that is in cmtact with the fault ecodult.
'Ihis does not seen possible. Please clarify.
As docunented in Attachment C,Section VI, varicus quantities of thernoccuples (T/Cs) are installed on the fault cables, target cables, fault conduits, target ecoduits and on otler 1ccations as apprcpriate (within the lirrits of the test facility). These T/Cs are allocated to 1ccations in proportion to their criticality. The T/Cs are then approxinately evenly spaced along the length of the test specinen. This results in scrre 1ccaticms being nere closely nonitored than other.s.
This ccodition can lead to the ccoditico identified in the question. The follcwing table portrays the T/C arrangenent for test 4/3:
Fault Fault Free Air Cable Corriuit Target Cable
- T/Cs Spacing
- T/Cs Spacing
- T/Cs gycing 8
16" 3
36" 8
12" As can be seen by this table, the target cable tmperature is mcnitored on 12" centers whereas the fault conduit is noni-tored cn 36" centers. 'Ihis allcus the possibility that the target cable taperature is mcnitored closer to the hottest point cn the fault cable (such as the point of slert circuit in the fault cable). The result wuld be that the neasured tenperature of the tottest spot cn the target cable is higher than the reasured tsperature of the lettest spot on the fault ccnduit, such as is the case in this instu.:e.
It shculd be noted that the target cable is exposed to the fault cable over the entire length of the test specinen (to the extent possible or as appropriate for the physical con-figuration) and is therefore subjected to wMtever degrada-tico nay result fran the wrst case taperature location.
The post cuercurrent electrical tests are irpcced on the l
entire length of the target cable thus detecting any unaccep-table degradation of th target cable. Therefore, the possibility that the T/C Iccaticn cn the fault cable ray not i
be precisely located to reasure the hottest spot on the fault cable or its asscciated raceway dces not affect the resu.ts of the test.
Page 2 of 4 l
5.
During c review of the insulatico resistance test data, it ms noticed that there seems to be a.ather wide variaticn (as such as three orders of negnitude) in the values cbtained, even for the sane cable types. Please clarify why this occurs.
'Ihe cables used in the separation test program wre the same types of fully qualified class 1E cables used at the plant.
Therefore the cause of the IR variaticn is not considered to be attributable to any defects or variation in the cable insulatico itself.
'Ihere are several possible reasons for variaticns in the readings.
Althrgh no records of lab humidity were kcpt, the w tential effects of humidity, tcuperature, and other envircomental factors on the test results is an irdustw-recognized con. sideration in the interpretatico of insulation resistance test results.i
'Ihe effe a well defined parameter.gts of tctrperature cn IR readings is However, the effects of humidity are highly variable and difficult to quantify. If the measurenents are taken with the equipient belcw the dew point, the possibility of noisture cordensatico on the cable insulation neg W mt lea 6 can Mw an effect on 3
the readings l
1/ "Electrical Equiprent Testing ard Maintenarce" by A. S. Gill, copyright 1982. Pages 16 ard 17. (The author is currently a mcsber of the ?bclear Regulatory Ccnmission staff.)
2/ Ibid, page 150.
3/ "A Stitch in Time...", A Manual on Electrical Insulatico
' ~
'Ibsting by Biddle Instrunents, d' nufacturer of Electrical a
'Ibsting and Precision Measuring Instnrents, Ccpyright 1982.
Page 30.
Page 3 of 4
A thirti potential factor for the IR variation is partial contamination of p test leads or exposed portions of the cable insulation. This surface ecntamination, possibly in conjunction with the presence of moisture condensation frcin the atnesphere, provides a leakage path resulting in 1cwer IR readings. At the high levels of resistance being neasured in the test (>1000 megohns at 1000 volts de), slight leakage paths can have significant effects on the measurments.
Further corrtboraticn of these factors effects on IR measure-ments is provided by IEEE Standard 43-1974, page 8 Although this standard is specifically for t}e testing of rotating machinery, the concepts regarding IR measurements are considered valid for other equipnen also.
Although the IR readings taken during the test did exhibit scoe variatico, the fact that all of them exceeded the pass /-
fail criteria of the test program by nearly two orders of magnittxie satisfies the purpose for which the measurements were intended.
1 l
l l
)
I 4/ Ibid.
Page 4 of 4
ATTACHMENT B FSAR PAGE CHANGES AND JUSTIFICATIONS TO ATTACHMENT A 0F LETTER GN-1434 DATED MARCH 14, 1988 i
l
- orsv s Lf cd. /s n'.3 Minimum Sp_et_ici Conf _iguration/Sncvico Loval Soperation 01stanco 2.
Cables in crd S --^- --; (r tray with cover 3/4 in.
on che bottom /'from non-Class 1E cables in tray or free air (the non-Class 1E cables are limited to 480V or lower voltage and size #2/0 AWG or smallerWnd located below or aloney side c.tcas.1E.tc.g),
at 5tt s OmIV 3.
Cables in b
trayA unning either vertically, or 1 in, horizontally (side-by-side) from horizontal non-Class 1E cable in tray :- ' ::
c' #(the non-Class 1E cables are limited to 480V or lower voltage and size #2/0 AWG or smaller).
caMe 3a f e s in + ray or hee. air-4-
f 2
r-5 re running either vertically, or 1-3/4 in.
horizontally (side-by-side) from horizontal non-Class 1E cable in t :, :If ree air (the non-Class 1E cables are limited to 480V or lower voltage and size #2/0 AWG or smaller).
4.
Tray (c) or free air cables to a non-Class 1E Contact rigid steel conduit carrying cables of 480V or lower voltage and sizes #2/0 AWG or smaller.
4a. Tray or free air cables to a non-Class 1E 3/4 in.
rigid steel conduit carrying cables of 400V or lower voltage and sizes #3/0 AWG through 500MCM.
- 5. Tray or free air cables to a rigid steel 1/2 in.
conduit (the free air cables, cables in the tray, and in the conduit are limited to 480V or lower voltage and size #2/0 AWG or smaller).
Sa. Cables in tray to a rigid steel conduit routed Coatect below or beside the tray (the cables in the tray, and in the conduit are limited to 480V or lower voltage and size 22/0 AWG or smaller).
- 6. Tray or free air cables to a non-Class 1E 1 in, flexible conduit (the non-Class 1E cables are limited to 480V or lower voltage and size #2/0 AWG or smaller).
Sa. Tray or free air cables to a non-Class 1E Contact stripped flexible conduit (the non-Clars 1E cables are limited to 480V or lower voltage and size #2/0 AWG or smaller).
- 7. Trey or free air cables to a flexible conduit 1 in.
j (the free air cables, cables in the tray and in l
the conduit are limited to 480V or lower voltage i
and size 22/0 AWG or smaller).
- 8. Tray or free air cables to e non-Class 1E 1 in, aluminum sheathed cable of size 28 AWG or smaller C. fM TW AM*Mr of 7nnwt, 7M* wif*s w 7Mer M m Ed W rMsW oW CkvDM"D 7)**f" f*&rr A$
cMgrdf5 N /9ffF-A/A sMf TW M"W "
h" t l
7MY #9A'I O/R M rly 4,% M"f2>
7D F),w" W gfkneenrac;> Ay 7ht* fA/M 7X2>
CAnfW # W 'fNfMf Ot M 7N4f 7A497* /r*r9W bcF~M A M <s,4cs),
h76 ex t ' Af l SA. 2o f l Minimum Spatial Confiouretion/Scrvico L0vol S a p o.t ? t i o n Dictanco i
or non-Class 1E electrical metallic tubing (EMT)
((APEC C)n)g I
carrying cables of sizes 28 AWG or smaller, f), (_p (Limited to lighting, communications, and fire hgg detection cables) 9.
Tray or free air cables to a non-Class 1E 3/4 in.
metal-clad ceblo (type MC) of size #8 AWG or smaller.
- 10. Tray or free air cables to a non-Class 1E 3/4 in.
steel-armored 480V cable (500 MCM or smaller).
10a. Tray or free air cables (480V or lower 3/4 in.
voltage and size #2/0 AWG or smaller) to steel-armored 480V cable (500 MCM or smaller).
- 11. Cables in flexible conduit to cables in 1 in.
flexible conduit (the cables are limited to 480V or lower voltage and size 500MCM or smaller).
11a. Cables in stripped flexible conduit to non-Contact Class 1E cables in stripped flexible conduit (the non-Class 1E cables are limited to 480V or lower voltage and size #2/0 AWG or smaller).
116. Cables in stripped flexible conduit to cables Contact in stripped flexibla conduit (the cables are limited to 480V or lower voltage and size #2/0 AWG or smaller).
j
- 12. Cables in flexible conduit to non-Class 1E Contact cables in rigid steel conduit (the non-Class 1E cables are limited to 480V or lower voltage and size #2/0 AWG or smaller).
- 13. Between two rigid steel conduits (the cables Contact in the conduits are limited to 480V or lower voltage and size #2/0 AWG or smaller).
l' 13a. Cables in rigid steel conduit to non-Class 1E Convact cables in rigid steel conduit-(the non-Cless 1E cables are limited to 480V or lower voltage and i
size #2/0 AWG or smaller),
14 Between perpendicular rigid steel conduits 1/8 in, carrying cables of 480V or lower volenge and sizea
- 3/0 AWG through 500MCM.
- 15. Cables in rigid steel conduit crossing non-Contact Class 1E cables in tray or free air (the non-Class 1E cables are limited to 480V or lower voltage and size #2/0 AWG or smaller).
The angle of cr'ossing shall be 300 or greater.
- 16. Free air cables to free air cables, where one 6 in.
4
- 1
^ ^
^
^
^
' 4 :,q x t y
/
e SA.
J<.
Minimum Spatial Configuration /Sarvico Lovol Soperation Dista_nco s
of the groups is wrapped in three layers (2Cs%
overlap) of silicon dioxide cloth (Siltemp 188 CH).
Service voltage is limited to 480V or lower voltage and sizes of 500MCM or smaller, h80V er low er V**lingC and ii L 4. of SCO MCM or small R F j
- 17. Free air cablesAto f r(e air control or 1 in.
instrumentation cables (28 AWG or smaller).
The control or instrumentation cables are wrapped in two layers (100% overlap) of silicon dioxide cloth (Siltemp 188 CH).
16 a.
From non C ia.ss a s f r e e o i r e.a.bles A Bov G in or lower va t+ag e an d s i t.e of soo M cM s ma1\\en w re ppeb A +k %re e. lay s.rs, or
(,2 co % e.v erlap ) o P s i l i co n A,i o w i d e c.t oth (, S i l + e.m p, I 88 c. H) fo c.l a 33 16 free.
o.ie co.bles,
a b
VEGF-FSAR-8 1
TABLE 8.3.1-4 (SLEET 4 OF 6) 3C Configuration / Service Level Minimum Spatial Separation Distance 18 13y Between free air instrumentation or 1 in.
control cables of 125-V de or 120-V ac or lower, sizes number 8 AWG or smaller.
l 9 14, Between free air instrumentation or In contact control cables (125-V de or 120-V ac or lower sizes number 8 AWG or smaller) with either group of cables wrapped in two layers (100% overlap) of silicon dioxide cloth (siltemp 188 CH).
Ao M.
Where raceways of different separation groups are brought to a single enclosure and:
The lower separation group (i.e.,
6 in.
a.
separation group installed below the other separation group),
wrapped in three layers (200%
25 overlap) ;* silicon dioxide cloth (siltemp 198 CH).
The cables are limited to 480 V or lower voltage of sizes 500 MCM or smaller.
1 (n % AWG o< smaller) b.
Oneseparationgroupikcontrolor 1 in.
instrumentation.cableM and is wrapped in two layers (100% overlap of silicon dioxide cloth.
Cables of the other separation group are limited to 480 V or lower voltage of sizes 500 MCM or smaller.
Iht.
Th; 2pp:
- p:ratien gecup-(i.e.,
1 in.
Fr e M e.pu =ste greup i==tetlee seve -
C 4.la 5 s J E' c.ble(s) the ;th;
- per
- ti
- . greup),
ggg, e er ene
____..u__
YCAnon
- Cl*38 2 6 EEEEihEEEEiEE'ikfwrappedintwo 4_ _ _
w.
Ccbksv;M Ac layers (100% overlap) of silicon Class f./ ca ble(s) dioxide cloth.
The4 cables are limited to 480 V or lower voltage of sizes 500 MCM or smaller.
ho A-CICLSS 16I Amend. 25 9/86 Amend. 30 12/86
i Page 1 of 2 Justification for changes to Table 8.3.1.4 Item 1 Paragraph 2 mistakenly equated solid bottom trays to trays with punched bottoms and bottom covers.
In solid bottom trays, the cables are in contact with the bottom of the tray.
In punched bottom trays with bottom covers, the bottom cover is set off the bottom of the tray by a lip.
This provides an air space between the cables and the bottom cover.
Solid bottom has been deleted from paragraph 2.
In addition, this paragraph did not include the restriction that the non IE fault cables be located selow or along side the class IE target tray.
This restriction reflects the actual test configuration in the Wyle testing.
Paragraphs 3 and 3a' mistakenly transposed wording.
This has been corrected to indicate that the target cables are in trays or free air.
Item 2 Paragraph 16 addresses free air to free air cables, with one cable wrapped in three layers (200% overlap) of silicon dioxide cloth (Siltemp 188), service voltage 480V or lower, size 500 MCM or smaller.
Wyle test 48141 02 configuration 4,
test la, was conducted with the fault cable wrapped and the target cable unwrapped.
Target cables do not require voltage or size limitations, since the test used the most conservative cable as the target cable.
Paragraph 16a has been added to remove the voltage restrictions of the target cable.
L
).
Page 2 of 2 Justification for changes to Table 8.3.1.4 (Continued)
Item 3 Paragraph 17 addresses free air cables to free air control or instrument cables (#8 AWG or smaller).
Wyle test 48141 02 configuration 4, test 2, was conducted with a target
(
cable wrapped in two layers (100% overlap) of silicon dioxide cloth (Siltemp 188), and a faulted cable. 480V or lower, size 500 MCM or smaller, unwrapped.
The voltage restriction of the faulted cable was inadvertantly left out of the previous change.
Item 4 Wyle test 48141 02 configuration 4 tests la and 2 were conducted with approximately 4 feet of fault cable in free air, outside of an enclosure.
Ta rget cables were routed over the fault cable.
The free air portion of the tested cables was long enough to be applicable to any configuration of cables in free air.
The cables being brought to an enclosure have no bearing on the application of the test results.
Therefore, the separation criteria restriction of paragraph 20 has been deleted.
When this change is made, paragraphs 20a and 20b are redundant to paragraphs 16 and 17.
Therefore, paragraphs 20a and 20b have been deleted.
Paragraph 20c has been renumbered to paragraph 20.
The renumbered paragraph 20 addresses free air to free air cables, with the target cable wrapped in two layers (100% overlap) of silicon dioxide cloth (Siltemp 188),
and the fault cable, 480V or lower, size 500 MCM or smaller, unwrapped.
Wyle test 48141 02 configuration 4, test 2, was conducted with a target cable wrapped in two layers (100% overlap) of silicon dioxide cloth (Sfitemp 188),
and a faulted cable, 480V or lower, size 500 MCM or smaller, unwrapped.
Target cables do not require voltage or size limitations, since the test used the most conservative cable as the target cable.
Paragraph 20 has been revised to remove the voltage restric.'ons of the target cable.
\\
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