TXX-4254, Forwards Summaries of Two Addl Biw Cable Environ Qualification Repts,Per 840719 Request to Address Concerns Resulting from NRC Insp.Cable Adequately Qualified
| ML20094N650 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 08/10/1984 |
| From: | Schmidt H TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC) |
| To: | Youngblood B Office of Nuclear Reactor Regulation |
| References | |
| TXX-4254, NUDOCS 8408160330 | |
| Download: ML20094N650 (16) | |
Text
..
TEXAS UTILITIES GENERATING COMPANY -
Log # TXX-4254 unywAr rowen. oo. von 1x ouve ramer 1,.B. M. DAM.AN, TeXAM WO!
File # 10010 903.11 clo August 10, 1984 Director of Nuclear Reactor Regulation Attention: Mr. B. J. Youngblood, Chief Licensing Branch No. l' Division of Licensing U. S. Nuclear Regulatory Commission Washington, D.C.
20555 4
SUBJECT:
COMANCHE PEAK STEAM ELECTRIC STATION DOCKET NOS. 50-445 AND 50-446 ENVIRONMENTAL QUALIFICATION OF BIW CABLE REF:
B.J. Youngblood letter to M.D. Spence dated July 19, 1984.
Dear Sir:
The referenced letter request that Texas Utilities address certain concerns that resulted from an NRC inspection of the qualification report of BIW silicone insulated cable. As an alternative to addressing these concerns directly, summaries of two additional qualification reports are attached. These summaries when considered in concert with the original report should make the concerns moot and show that the cable is adequately qualified for use as the Comanche Peak Steam Electric Station.
spectfully, H.C.
chmidt DRW/gj Attachment Original + 5 copies 8408160330 840810
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Qualification of Prefabricated 600V Single and Multiconductor 81W Cables with Silicone Rubber Insulation G&H Specification 3232-ES-130 CPSES P.O. CP-0465-4 TESTS PERFORMED
-The Franklin Institute Research Laboratories (FIRL) Test Report F-C4497 Qualification Tests of Electric Cables Under Simulated Reactor Containment-Service Conditions Including Loss-of-Coolant Accident, date March 1977, documents results of tests made for General Electric Company on GE supplied speciments of Silicone insulated electric cables. GE supplies the silicone rubber insulation materials to BIW for fabrication of cables supplied to CPSES.
However, there is no additional information available to verify that the cables tested by FIRL are fabricated similarily to the cables BIW supplied to Comanche Peak.
Included within the FIRL Report is a section from BIW's qualification Report 761039 - Cable Tray Fire Propagation Test With Vertical Tray Flame Test Data.
This test specimen, Type No. LSS-1989B, was for cable constructed of:
Conductors
- 2/C #16 AWG 7/0.0192" tinned copper Insulation
- Flame retardant silicone rubber, 30 mil wall Binder Type
- Flame retardant Shield
- Aluminum / Polyester tape with #18 AWG drain wire Outer Jacket
- Flame retardant silicone rubber, 45 mil wall Also included in the report was a statement to the effect that the cables for Report F-C4497-4 were furnished to Franklin Institute Research Laboratories by the supplier of the silicone rubber insulation and are similar to those which will be supplied by BIW to CPSES.
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-s
/These reports were reviewed by G&H 'and TUGCO and judged acceptable for qualifying prefabricated 600V single and multiconductor. cables with silicone. rubber insulation to be used to transmit control signals to Class 1E equipment located outside and inside the CPSES containment.
l To further substan'tiate that BIW silicone rubber insulated cables are acceptable for safety related application, reference is now made to other testing, for both inside and outside containment use, that has
~
been performed on sections of BIW silicone rubber insulated cables-associated with the qualification testing of Litton electric connectors to connect control and power cables-(also obtained under specification ES-13D).
Tests were performed by both BIW and by the Veam Division of the Litton System.
The following pages provide' summaries of these tests.-
l u
l, 8-
_3.
I.
BIW Report #82E080-TU, Rev. 1 - In-Containment Prefabricated j
Cables Assemblies l
-A.
INTRODUCTION Two (2) assemblies consisting of 3 conductor #16 AWG cable, BIW Part No. 14329-8003 in 15'7" of American 80A 3/4" flexible conduit, with a Litton CIR-00-PV-20-33P plug on each end were connected to mating Litton CIR-06-PV-20-335 receptacles mounted in the wall of the autoclave. (At CPSES all silicone rubber cables are installed in conduit.) The cable has silicone rubber insulation, aluminum-polyester tape shield with drain wire and silicone rubber outer jacket. The silicone rubber insulation and jacket have glass braid covering.
This assembly was subjected to the LOCA cycle defined in the table below.
TABLE 1 - TEST CYCLE TEMPERATURE PRESSURE TIME (OF)
(psio) 0-10 seconds Room Temp - 370 0-155 10 seconds - 4 minutes 370 155 4 minutes - 10 minutes 350 120 10 minutes - 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> 300 55 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> - 5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> 300 - 140 55-0 5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> - 5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> 10 seconds 140 - 370 0-155 5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> 10 seconds - 5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> 4 minutes 370 155 5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> 4 minutes - 5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> 10 minutes 350 120 5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> 10 minutes - 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> 300 55 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> - 30 days 300 55 30 days - 30 days 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> 300 - 100 55-0
' 4_
A 1
~
The samples tested were aged 750 hours0.00868 days <br />0.208 hours <br />0.00124 weeks <br />2.85375e-4 months <br /> at 1600C followed by 50 megarads gamma radiation!(Cobalt 60). Aging and irra-diation were performed prior to the LOCA cycle.. The thermal aging'was performed in circulating air ovens and is equiva-l lent-to 40 years at 900F, A comparison of these conditions and Specification 2323-ES-13D, Paragraph 3.4.3 environmental conditions is given in Figure I.
B.
PROCEDURE The sample of 15'7" with connector couplings at each end was placed in an autoclave chamber with the Litton CIR connectors mounted into a stainless steel flange. An additional length of cable outside the autoclave chamber was fastened to the Litton CIR connectors for purposes of test measurements.
The sample was exposed to the LOCA cycle as described in Table 1.
STEP 1: After 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> the samples were removed and subjected to a post-LOCA test consisting of (1) bend around a 50X mandrel after which a 750 VAC potential was applied to each conductor for 5 minutes.
STEP 2:. Remaining 29 days of cycle.
L
' FIGURE I ANALYTICAL' COMPARISON OF SPECIFICATION 2323-ES-130 AND SECTION A LOCA ENVIRONMENTAL CYCLES Using the Arrhenius technique, analysis may be used for a comparison of the Specification 2323-ES-130 LOCA with the profile of Section A.
Referring to Figure VIIIC for a similar (not identical) General Electric silicone rubber compound, it is seen that for every 8.50C (15.30p) change in temperature the aging time is either halved or doubled (Line A). Mathematically this can be expressed as follows:
T2 Where:
T1 = time at temperature ti T1 =
T2 = time at temperature t2 l
fti-t)
T1 and t2 are in 0F 2
(15.3'/
l t
2 For convenience the elapsed times at each temperature may be related to an equivalent exposure at 1500F (the long term temperature in Specification 2323-ES-13D, Paragraph 3.4.3usingtheaboveequation).
1 Example: Calculation for 30 minutes (0.5 hr.) at 2800F 0.5 T1*lr150-280}=
0.5 0.5
= 180.5 hrs.
=
2' 15.3 '
?.(-3.497)
.00277 Specification 2323-ES-130 Profile (Section 3.4.3) 0.5 hr at 2800F is equivalent to 180.5 hr at 1500F 9.5 hr at 2400F 558.8 "
1500F 86 hr at 2000F 826.9 a 1500F 8664 hr at 1500F 8664.0 "
1500F Total is equivalent to 10230.2 hr at 1500F
g Qualification of Prefabricated 600V Single and Multiconductor BIW Cables'with Silicone Rubber Insulation G&H Specification 3232-ES-130' CPSES P.O. CP-0465-4 TESTS PERFORMED -
The Franklin. Inst!itute Research Laboratories' (FIRL). Test Report F-C4497 Qualification Tests of Electric Cables Under Simulated
' Reactor Containment Service Conditions Including Loss-of-Coolant-Accident, date March-1977, documents results of tests made for General Electric Company on GE supplied speciments of Silicone insulated electric cables. GE supplies the silicone rubber insulation materials to BIW for fabrication of cables supplied to CPSES. 'However, there is no additional information available to verify that the cables tested by FIRL are fabricated similarily to the cables BIW supplied to Comanche Peak.
Included within the FIRL Report is a section from BIW's qualification Report 761039 - Cable Tray Fire Propagation Test With Vertical Tray Flame Test' Data.
This test specimen, Type No. LSS-19898, was for cable constructed of:
Conductors
- 2/C #16 AWG 7/0.0192" tinned copper Insulation
- Flame retardant silicone rubber, 30 mil wall Binder Type
- Flame retardant Shield
- Aluminum / Polyester tape with #18 AWG drain wire Outer. Jacket
- Flame retardant silicone rubber, 45 mil wall Also included in the report was a statement to the effect that the cables for-Report.F-C4497-4 were. furnished to Franklin Institute Research Laboratories by the supplier of the silicone rubber insulation and are similar to those which will be supplied by BIW to CPSES.
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!Section A Profile *
.063'8 hr._(3.83 min) at 370 F is equivalent to 1360.3 hr. at 150 F 0
-0.1 hr. (6 min) at 350 F "
862.1 150 F U
2.83 hr. -
at 300 F "
2526.8 150 F
.0638'-hr. (3.83 min) at-370 F "
U 1360.3 150 F 0.1-hr. (6 min)
- at 350 F " '
862.1 150 F U
18.83 hr.
at 300 F "
16182.5 150 F Total is equivalent to 23784.1 hr. at 150 F(1) 0 696.0 hr. (29. days) at 300 F is equivalent to 621428.6 hr. at 150 F(2)
Total for 30 days is equivalent to 645212.7 hr. at 150 F
- 10 second' heat-up times an'd 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> cooldown times are omitted from this comparison and consequently provide additional margin.
(1)
.The assemblies passed the post-LOCA test after a equivalency of 23,784.1 hours1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> at'150 F, exceeding the Specification 2323-ES-130 profile equivalency of 10,320.2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> at 150 F by a margin of over 100%. The higher pressures in the Section A profile compared with the Specification 2323-ES-130 requirements provide additional margin.
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]
(2)
The equivalency of 621,428.6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> at 150 F after the post-LOCA i
test provides additional margin.
Except during those intervals when insulation resistance was-being measured, the samples were energized at 600 volts RMS conductor to conductor with a current of 1 amphere flowing through each.
The samples were sprayed with a chemical solution consisting of 6,200 PPM Boron mixed with 50 PPM Hydrazine.
This solution was recir-culated for the duration of the test with its pH being maintained between 8.6 and 10 by the addition of trisodium phosphate.
The 4
2 spray rate was 0.15 (gal / min)/ft.
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. 3, C.
MEASUREMENTS The insulation resistance was measured using a General Radio Model 1862C Megohmeter at'a potential of-500 VDC.
POST LOCA TEST
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Upon their removal from the autoclave, each sample was subjected
'to a post-LOCA test consisting of the following:
1.
I bend around a 50X material.
2.
750 VAC conductor to conductor and drain wire for 5 minutes.
Results as follows:
SAMPLE #1 Conductor A (Black) - Pass Conductor B (White) - Pass Conductor C (Red)
- Pass SAMPLE #2 Conductor A (Black) - Pass Conductor 8 (White) - Pass conductor C (Red)
- Pass TEST RESULTS Sample #1 and #2 held 600 volts RMS conductor to conductor with a current of 1 ampere flowing through each conductor throughout the 30 day test cycle. Pass-fail criteria are based on the ability to function electrically by holding rated voltage and carrying rated current throughout the LOCA environmental cycle in accordance with
(
IEEE 383-1974, Section 2.4.3.2.
The assemblies passed this requirement.
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II.
Qualification Test of Electric Connectors Under A Simulated LOCA/DBE By Sequential Exposure to Environments of Thermal Aging, Background Radiation, Containments Pressurization, Vibration, Radiation (Accident level), Steam and Chemical-Spray - Performed for Litton Precision Products by Component Testing Division of Isomedix, Inc., dated November 1978 Description - Test Sample #BC1/BC2 The sample connector set was assembled by Boston Insulation Wire and Cable ~ Co. utilizing silicone rubber jacketed single conductor of their own manufacturer.
Cable: BIW Type LSS 2182A - Similar to the type LSS-19898 for which cable tray fire propagation and vertical tray test were performed and documented in BIW report 761039.
SECTION 3.
TEST PROCEDURES 3.1 Purpose The purpose of the program is to provide qualification tests on electrical connectors in accordance with the suggestions contained in IEEE 323-1974, "IEEE Standard for Qualifying Class 1E Equipment for Nuclear Power Generating Stations", IEEE 383-1974, "IEEE Standard for Type Test of Class 1E Electric Cables, Field Splices, and Connections for Nuclear Power Generating Stations",
and IEEE 344-1975, "IEEE Recommended Practices for Seismic Qualification of Class 1E Equipment for Nuclear Power Generating Stations".
SECTION 4.
CONNECTOR PREPARATION AND ELECTRICAL TESTING 4.1 Connector and Cable Mounting The connector a'nd associated cable were coiled, suspended and secured inside the pressure vessel. Wire was used to support and secure the sample in place.
The ends of the cable were brought through the vessel hed penetrations and connected to the energizing lead wires.
The terminating stainless steel tubing (housing the cable) was secured to the vessel by standard tube fittings.
4.2 Electrical Energizing and Interconnections The cable-ends were secured to terminal blocks mounted on the vessel head. Lead wires were used to connect the energizing switch box with the samples' cable.
The switch box consisted of two knife switches arranged so that the four conductors of the cable and connector could be monitored, removed from the circuit if failure occurred, or isolated during measurements of insulation resistance.
During the LOCA simulation the four conductors were energized at 600 Vac and 20 amperes.
4.3 Measurements of Insulation Resistance (IR)
IR measuremerits were made periodically during the test program as a means of monitoring the relative performance of the test sample.
Specifically, IR measurements were made at the following times during the program, 1.
Upon receipt at Isomedix.
2.
At the middle and end of Phase I - Thermal Aging.
3.
At the end of Phase II - Radiation Aging.
4.
At the end of Phase III - Containment Pressurization.
5.
Upon reciept at Isomedix after Phase IV - Vibration J
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Endurance / Seismic Simulation.
6.
At the end of Phase V - Accident Radiation.
- 7.
At each dwell during the high temperature phases of the steam / chemical-spray exposure period.
8.
Once each day during the four-day dwell.
9.
Twice weekly during the' balance of the 30-day steam / chemical-spray exposure period.
10..
At the conclusion of the LOCA exposure cycle.
The measurements werc made after application of 500 Vdc for one minute, by reading between the conductor and ground.
During the LOCA simulation, when IR measurements were taken, prior to actually making the measurments, the current and voltage potential load were removed from the conductors. At the conclusion of the IR measurements, the conductors were put back into the circuit.
4.4 High Voltage Withstand Tests (HI-P0T)
At the conclusion of the exposure period, the sample was removed from the vessel, the cable straightened and wound into a coil 40 times its diameter. The sample was submersed in water and each conductor, in turn, was subjected to a potential relative to that conductor and the other conductors connected to ground.
The potential applied was 2200 volts ac (twice the rated voltage plus 1000).
J SECTION 5.
ACTUAL TEST CONDITIONS i
5.1 Phase I - Thermal Aging The sample was thermally aged at 1600C for a period of 15 days simulating an ambient temperature of 1400F over the 40 year design life. A forced air circulating oven as used to age the sample.
The heater controls on the oven were adjusted to automatically maintain the temperature at 1600C.
The measurements of. insulation resistance were made at the middle and end of the thermal exposure at room ambient conditions.
5.2 Phase II - Background Radiation Aging For radiation aging,.the mated pair, with its associated lead _ wire, was placed'in a radiation facility and subjected to a Cobalt-60 source of gamma radiation at an exposure rate of 0.58 megarads per hour. The sample was removed after it had recieved an accumulated dose of 70 megarads.
At the conclusion of this phase, insulation resistance measurements were made at room ambient conditions.
5.3 Phase III - Containment Pressurization The mated pair connector was placed in a pressure vessel and the vessel sealed. Air was admitted to the vessel to raise the pressure inside the vessel to 65 psig.
This pressure was maintained for five minutes before being reduced to atmospheric pressure.
The pressure inside the vessel was raised and lowered in this manner for a total of 15 cycles.
At the end of the 15th cycle, the mated pair was removed from the vessel and insulation resistance measurements were taken.
.4 Phase IV - Vibration Endurance /Sesimic~ Simulation (Applicable to Connector only).
5.5 Phase V - Accident Radiation The mated pair connector, with its lead wire, was placed in a radiation facility and subjected to a Cobalt-60 source of gamma radiation at an exposure rate of approximately 0.3 megarads per hour. The sample was removed from the radiation facility after it had received an accumulated dose of 40 megarads.
Insulation resistance measurements were made on the connector at room ambient conditions.
I 5.6.
Phase VI - Loss-of-Coolant Accident'(LOCA) Simulation The sample connector was placed in a vertical pressure vessel for exposure to steam and chemical-spray.
The lead wires of the connector were electrically energized at 600 volts ac and 20 amperes prior to'the start'of the exposure.
To initiate the exposure, steam was rapidly admitted into-the vessel, raising the temperature and pressure to-3400F/105 psig. These conditions were maintained for one hour before being reduced to 1350F at 0 psig over a one hour period.
This temperature and pressure (1350F/0 psig) were maintained for a one hour period.
For the initiation of the second transient, steam was rapidly admitted into the chamber raising the temperature and pressure to 3400F/105 psig.
The temperature and pressure were held at this point for a period of three hours. At that time, the conditions were reduced to 3200F at 75 psig and maintained for three hours. After this time period, the temperature and pressure were reduced to 3000F/55 psig and maintained for four hours.
At this time, the temperature and pressure were reduced to 2500F/15 psig and held at this point for the remainder of four days. After the four-day period, the temperature and pressure were reduced to 2000F at 0 psig and held for the remainder of the 30-day exposure.
Approximately 50 seconds after initiating the steam exposure, a chemical solution consisting of 3000 ppm baron as boric acid in solution with 0.064 molar sodium thiosulfate buffered with sodium hydroxide to a pH of 10 at room temperature was continuously sprayed into the vessel at a rate of 2 gpm.
The-chemical-spray solution pH was maintained between 9.5 and 10.5 throughout the simulation period.
The spray remained on throughout the entire LOCA exposure.
At the total test time of 30 days, the entire system was shutdown and the connector removed from the vessel.
a
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~,l L5.7. ' Post-LOCA' Tests-
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Atithe conclusion of the simulated LOCA event, insulation
~
resistance' measurements were made. LThen the sample's-lead wires
.were. straightened and recoiled-into a coil of 40 times-the cable diameter.-:While so wound, the connector and cable w'ere submersed in water and subjected to'a high voltage. withstand test at 2200 volts a.c. for a period of five minutes.
SECTION 6.-
TEST RESULTS'AND DATA 6.1 Insulation. Resistance Measurements Measuremen', of IR were made at the times previously mentioned in Section'3, and the results were all acceptable.
6.2 High_ Voltage Withstand Test (HI-P0T)
Table 4-represents the results of the HI-P0T test performed at the conclusion of the test program.
TABLE 4 RESULTS OF HIGH VOLTAGE WITHSTAND TEST PERFORMED AT CONCLUSION OF 30-DAY LOCA SIMULATION CONNECTION TIME V0LTAGE APPLIED AC LEAKAGE CURRENT
.(conductor)
HELD (Minutes)
VOLTAGE (Volts)
(MA)* IN WATER A
5 2200
<1 B.
5 2200
<1 C
5 2200
<1 0
5 2200
<1
- No meter movement observed.
1
r.
g SECTION 7.
CONCLUSION Connector sample BC1/BC2 successfully completed the 30-day LOCA simulation after exposure to a total accumulated' dose of 110 megarads of Cobalt-60 gamma radiation, 15 days thermal aging at t-
{
1600C,15 cycles of pressurization at a maximum of 65 psig pressure, and vibration endurance / seismic simulation.
Also, the sample held the post-exposure high voltage withstand potential'of 2200 volts-ac for five minutes.
SUMMARY
The three test reports discussed above and the type' tests asso-ciated with these reports properly demonstrate the qualification of BIW silicone rubber insulted cables at CPSES.
Any concerns or questions that might arise from examining only one report are satisfied by considering all three reports together.
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