ML20128A667
| ML20128A667 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 01/28/1993 |
| From: | William Cahill, Walker R TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| TXX-93061, NUDOCS 9302020280 | |
| Download: ML20128A667 (9) | |
Text
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r File # 10010 TUELEC7RIC Ref.
50.48 January 28, 1993 William J. cablP. Jr.
o,mwe r,,,ua,r U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555
SUBJECT:
COMANCHE PEAK STEAM ELECTRIC STATION (CPSES)
DOCKET NO. 50-446 RESPONSES TO REQUEST FOR ADDITIONAL INFORMATION FOR CPSES UNIT 2 REF:
1)
TU Electric letter logged TXX-93038 from Mr. William J. Cahill, Jr. to the USNRC dated January 19, 1993 2)
TV Electric letter logged TXX-93023 from Mr. William J. Cahill, Jr. to the USNRC dated January 19, 1993 3)
TV Electric letter logged TXX-93060 from Mr. William J. Cahill, Jr. to the USNRC dated January 25, 1993 Gentlemen:
During teleconferences on January 25 through 28, 1993, with your Staff.
TU Electric committed to provide additional clarification for the following:
a)
Test Scheme 1 During the January 25 teleconference, the NRC raised a concern regarding the' acceptability of Scheme 1 (36 inch wide cable tray). TV Electric in it's response to previous guestions has fully described the justification for acceptability of this Test Scheme within the Unit 2 Ther'no-Lag qualification basis (reference 3. TXX-93060).
The specific con' the NRC raised, pertains to the Omega Point Laboratories (OP sort. On page 16 of the test report, under
.iie observation column states that; "[T]he
" Post-Test Examir.u i v..
panel was burned through to the stress skin in 2-3 inch diameter areas at many locations across the bend area". TV Electric reviewed this statement during it's review of the Test Reports and based on actual test observations had not identified this wording as an issue of n 'i n -s 4 hg// O 9302020200 930128 I
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TXX-93061 Page 2 of 5 concern. TV Electric's conclusions are supported by the statement on page 15 of the Test Report (Scheme 1), which states that; "[P]rior to the hose stream test, no openings or other severe damage was noticed on the specimen".
In addition, subsequent review of the photograahs on pages 419 and 422 show the area of the test assembly and the bacc side of-the p'anel in question. These photographs do not reveal that~"burnthrough occurred.
Therefore TU Electric reconfirms that no "burnthrough" occurred and the test yielded acceptable results.
Notwithstanding. TV Electric requested Omega Point Laboratories to interpret the observation as documented in the test report. Their letter clarifying this observation is attached as attachment 1 to this
- letter, b)
Conduit Support Modifications To clarify our previous response to question 23, of reference 2 (TXX-93023, attachment 2),thedesignmodificationsassociatedwith conduit supports have been verified for design adequacy and are
- complete, c)
Use of Test Scheme 9-3 Results TU Electric has reviewed the NRC Staff's questions relative to this test and offers the following clarification.
The results of Test Scheme 9-3 which included 3/4 inch, 1-1/2-inch and ( inch diameter conduits were r
included with all other test reports submitted by reference 3 (TXX-93023)_forcompleteness. We do not utilize this test as part of s
the-qualification basis for Unit 2 Thermo-Lag configurations.
Reference i
to this test was included in ER-ME-082, " Evaluation.of Unit 2 Thermo-LagConfigurations"(attachment 5toreference3)onlyasoneofseveral supporting factors for the acceptability of minor deviations from tested conduit configurations.
Therefore, since reliance on this test is not-required, ER-ME-082 will be revised accordingly.
d)
ASTM-E-119 In response to your Staff's request, TU Electric maintains that the methodology and criteria utilized during our Thermo-Lag fire test program for assuring adequate cure of-the test assemblies satisfies the moisture content provisions of ASTM-E-119, section 11. Each of the test reports. include a " Moisture Content Log" documenting such activities.
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1 TXX-93061 i
Page 3 of 5 e)
Scheme 11-1 1.
Cable Installation:
The cable conditions observed during the 11-1 fire test was not jacket charring due to elevated temperatures. During the fabrication of the cable specimen for the air drop assembly, the cables were bundled together by ty-wrapping, after installation of the thermocouples.
The bundling is necessary to assure that the thermocouple locations are maintained.
Bundling effectively creates one cable mass and may result i
in stresses being introduced on individual cables during the installation process when the cable mass is fed through a sleeve.
As the cables were heated during the fire test, relaxation occurred within the cable jackets which had been stressed during the installation process. This allowed the cable jacket to balloon and conthet the Thermo-Lag 330-660 "flext-blanket".
It should be noted that-blistering caused in this manner will be limited
'f to the outer surface of the jackets (this is supported by visual inspectionoftheconditionsobservedonthetestsamples)andcable operability will not be effected.
Cables installed at CPSES are not subjected to the stresses experien "<l during assembly of the fire test specimen, because of the following installation practices:
1)
Cables are not ty-wrapped together during pulling activities.
2)
Cables installed in conduit utilize cable pulling lubricate.
3)
Cable bending radius requirements are adhered to during cable pulling.
4)
Cable sidewall bearing pressure limits are not exceeded during cable pulls.
5)
Cables are configured in a manner which will allow smooth installation into the raceway.
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i TXX-93061 Page 4 of 5 All of these factors will allow cables to freely move during the pull, and the binding experienced during the fire test assemblies can not OCCUR.
2.
Test Report Data:
Several inconsistencies in the test report have been brought to our attention. TU Electric has forwarded these to Omega Point Laboratories.
A 10tter clarifying these inconsistencies is attached as attachment 2 to this letter.
Aoditionally, TU Electric will revise it's Engineering Report ER-ME-067 accordingly, f)
Box Enclosure ( nfiaurations for specific plant configurations, notably cable air drops entering single and multiple cable trays through embedded sleeves and air drops between two cable trays in close proximity, TV Electric has utilized Thermo-Lag " box enclosure" designs. These designs are based on and consistent with wide cable tray configuration tests.
For these unique configurations, the protective envelope for the cable tray (s),
consisting of Thermo-Lag 330-1 panels, is extended to effectively enclose the entering cables. Where these configurations are located adjacent to walls, floors or ceilings,-the structural integrity of the assemblies are generally enhanced by direct attachment to the concrete structure with mechanical fasteners, such as anchor bolts.
All joints and seams associated with these assemblies are reinforced with methods qualified by wide cable tray tests. The thermal characteristics of these configurations have been evaluated based on successful tests of protective envelopes installed on single cable trays of various sizes which contain significantly less mass and as such are more thermally challenging to the 'nrrier. Also, where these configurations are moun.>d directly against concrete structures, one or more sides of the asserrelies are shielded by the strccture and hence prevent potential fire exposure. Finally, the concrete structure has heat sink properties which result in reduced temperatures inside the enclosures.
TU Electric understands the NRC Staff has concerns relative to qualification of these configurations by test.
In light of these concerns, appropriate compensatory measures (i.e., fire watches) will be implemented as described below, where such " box design" configurations are located. There measures will remain in place until such time that this issue is resolved with the NRC Staff.
g)
Carnpensatory Measures TU Electric offers the following in response to the NRC Staff's question regarding compensatory measures (reference 3, attachment 1). Areas that contair, fire-safe shutdown conduits or cable trays, of all sizes l
TXX-93061 Page 5 of 5 he 30 day cure time will protected by Thermo-Lag, which do not r.no require fire watches as compensatory mes e, a in accordance with the Fire Protection Plan.
TV Electric will remove the fire watches when 30 day cure time has been met.
Should you have any questions or need additional information please contact Obaid Bhatty at (817) 897-5839.
Sincerely,
'1 William J. Cahill, Jr.
M By:
~
Roger D. Walker Manager of Regulatory Affairs for NEO OB/tg : Clarification from OPL 2:
Clarification of Test Report inconsistencies from OPL c-Mr. J. L. Milhoan, Region IV Mr. T. A. Bergman, NRR Mr. B. E. Holian, NRR Resident Inspectors, CPSES (2) f!
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_ to TXX-93061 Page 1 of 2
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o January 26,1993 TU Electric-CPSES Farm Rond 56 P.O. Box 1006 Clen Rose, Texas 76043 ATTN:
Ruudy Huoten Re:
Project No.12340 93543b Schemo 1, Assembly 2
Dear Mr. Hooten:
This letter will servo to explain my use of the term "Imrood through"in the pont.-
test observation of the condition of the panellocated on the outside curved portion of the 24" radius 00* (see page 16, Report No. 13340 03543b, September 9,1992).
The Thermo-Lag panel across the ouWide of the 90* bend contained a thin layer of
~
unreacted Thermo Lag material, except for several areas where the Thermo-Lag was " browned clear through." By this, I do not mean to indicate that there was exposed stress-skin. I simply mean to relay that the remaining material covering the stress-skin at those locations was brown and not white. The Thermo Lag material contains fibers which tend to keep it in place over the stress skin, unless very severely burned.
Examining the photographs, it can be seen that after the fire test and before the hose stream Wat (page 414, bottom photo) there was still an unbroken layer of ash over the 90 bend. Following the hose stream test, the photograph (page 419, bottom photo) shows no exposed stress-skin. Removing the Thermo-Lag panel from the bend area (pag'e 421, bottom photo) showed no heat 4nduced damage to-the cables. The back ot the Thermo-Lag panel which covered the 90' bend (page 422, tnp photo) shows several locations where the material has " browned" deeper than the rest. These are what I termed %urned through."
sS68 Alamo Downs Parkway San Antonio Texas 78238 612 / 647-8253 TELEX: 9102400828 SWCS UO FAX: 512 / B47-0015
_ _ _ _ _ _ _ _ _ _ _ _ _ _ to TXX-93061 Page 2 of 2 TU Electrie January 26,1933 Randy "coten Poco 2 I realize that the use of the words " burned through" was an unfortunate one, sinco others consider thnt in mean that the material had a hole in it I npningize for any inconvenience that may have caused you, and will gladly discuss the issue with anyone who would care to call me.
Sincerely,
/
I Deggary/
N. Priest President
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to TXX-93061 Page 1 of 2
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4 January 28,1993 TU Electric - CPSES Parm Road 56 P.O. Bar 1006 Glen Rose, Texaw 76043 ATTN:
Randy Hooton Re:
Project No.12340-94367e Schema 11 1
Dear Mr. Hooton:
This letter serves tu addren cumments and concerns regarding Reputt No.12340-94367e as listed in your letter of January 27,1993.
Examining the graphical data (pages 204 207) and the respective tabular data (pages 275 278), it can be seen that thermocouples #193 (3 conduit steel), #194 (2" conduit steel) and #196 and #197 (1" conduit stoeD suffered from the condensate saturation anomaly. The anomaly did not occur in the 5" conduit. The " dagger" annotation abr the phrase "5 in. Conduit Steel" in the table on page 24 of Report No.12340-94367e should not be there. The annotation is correct in all other occurrences, although the explanation of this annotation abould read "Some or all conduit steel temperatures were affected by condensate aaturation." The paragraph on page 22, discussing the saturation problem, should also have -
addressed these conduits.
The condensate saturation anomaly manifests itself as fluctuating temperature readings followed by sudden, sharp temperature reading increases and/or decreases. Reintive to the statement "Early in the test,.. " on page 22, there is no way of knowing at what point in time the thermocouple lead wires actually became naturated and began reading erroneously. The peak in temperature readings of affected channels near the end of the test is the earmark of the water being driven out uf the coudeusate, uut the beginning of the erroneous readings.
Experience has shown that this anomaly causes thermocouples to register temperature readings that are higher than actual surface temperatures. The conclusion drawn in Report No. 12340-94367e is, therefore, valid. Even though the temperatures listed in the tabular data for these affected thermocouple channels may be erroneous, they represent erroneously high temperatures and are still well within the bounds of allowable limits.
G868 Alamo Downe Parkway San Antonio, Texas 78238 512 / S47-5253 TELEX: 9102400028 SWCS UQ FAX: 512 / o47oo1G
_ _ _ _ _ - to TXX-93061 Page 2 of 2 R1 l'lcetric January 28, AM3 Page 2 Randy Hooton It has also been found that the length of affected thermocouple lead wire greatly affects the degree to which this anomaly occurs due to saturation by the condensate. In the case of the thennocuuple lead wires attached to the 1",2",8" and 5*"* conduit stubs, the length of wire exposed to the possibility of this unomaly was less than l'. It can be concluded therefore, that while the anomaly t
manifesteditselfin several of the thermocouples en the surfaces of these conduit stubs, it did so to a very slight degree in comparison with previously affected test articlea. % temperature " swings" would therefore, be expected to be smaller than in previous tests.
I hope that thin clears up any ambiguity surrounding thia test report. if any further questinus, comments or concerna should arise regarding this, or any utber report,, feel Lw to call sue. I apologize for any inconvenience that this may have caused you, and will gladly discuss the issue with anyone who would care to call me.
Sincerely,
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Herbert W. Stansberry II Senior Laboratory Technician HWS/dbm oh-iQ,$%
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