ML100271834
| ML100271834 | |
| Person / Time | |
|---|---|
| Site: | Indian Point  |
| Issue date: | 07/15/1970 |
| From: | Boston Insulated Wire & Cable Co |
| To: | |
| Shared Package | |
| ML093430851 | List: |
| References | |
| B903A, NUDOCS 8202090375 | |
| Download: ML100271834 (17) | |
Text
BOSTRAD 7 INSULATED WIRES ELECTRICAL PERFORMANCE AND FLAME RESISTANCE BEFORE AND AFTER IRRADIATION REPORT NO. B903A JULY 15, 1970 WIRE& CAOLE CO.
65 BAY STREET BOSTON, MASSACHUSETTS 02125 8202090375 920204 PDR ADOCK 05000286 PDR p
INTRODUCTION The data in this report provides istics of various insulated wires in detailed performance character response to the needs of the users.
It supplements the information provided in BIW Reports No. B9Oland B902.
The evaluation of the data presented in with the assumption that all of the performance this report should be made and cable in the containment vessel of requirements for wire a nuclear power plant must be met. The consideration of any specific the other characteristics can lead to feature independent of all of different conclusions. The perfor mance characteristics desired by the individual reviewing this data should be the deciding factor in the selection of materials.
OBJECTIVE The objective of this report is to of radiation on the electrical and 'flame study the effects of large doses resistance properties of various materials recommended for nuclear power plant applications.
CONCLUSIONS
- 1. There may be wide variation in different formulations of any one base material.
- 2. EPDM and EPM showed superior performance in all tests except flame resistance. The best insulations for flame resistance were Bostrad 7 and Bostrad 7S.
- 3. From this process of elimination,, the most desirable construction would be Bostrad 7E which maintains the balance of properties necessary to meet the require ments of the nuclear power plant containment vessel.
This evaluation was based on the testing of unjacketed wires. When used in multiconductor cables with jackets and other protective layers, the choice of single wires for use within the cable could be broader, and specific choices would depend on the particular flame test used.
SUMMARY
This report presents the performance characteristics of several compounds of CSPE, EPM and EPDM. The folowing measurements were taken before and after radiation at 1 x 10 rads:
(a) Insulation resistance (b) Insulation resistance constant (c) Mechanical water absorption (d) Capacitance stability (e) Dielectric strength (f) Dielectric constant (g) Flame tests 3
RESULTS Single Layer Extrusions -- CSPE Compounds Bostrad 7 GR 838 and GR 789 are all compounds of CSPE. GR 789 must be eliminated as a candidate construction because of the large change in capacitance when irradiated to 1 x 108 rads as well as its inability to meet the IPCEA vertical Flame Test.
Although GR 838 has better electrical stability than GR 789, its marginal performance on flame tests limits its usefulness.
Bostrad 7 exhibits reasonable stability on 14 day immersion, has reasonable insulation resistance and dielectric strength and meets the IPCEA Vertical Flame Test.
The performance of the three CSPE compounds tested are quite different and reflect the compounding art. Although the basic constituent materials are the same, the specific final compounds reflect the difference in performance.
Single Layer Extrusions -- Ethylene Propylene Both compounds, GR 853A and GR 861 exhibit excellent electrical properties and stability. The level of stability indicated by the data would make them extremely suitable as wiring for almost any application. However, their inability to meet the IPCEA Flame Test must eliminate these constructions from considera tion as well.
Two Layer Extrusions -- Bostrad 7S and Bostrad 7E The two layer constructions represented by Bostrad 7S and Bostrad 7E bring together the best properties of their constituent materials. Bostrad 7S maintains good stability with irradiation and water immersion and meets the IPCEA Flame Test. Its dielectric strength is somewhat lower than the other wires tested.
Bostrad 7E maintains the electrical stability and high insulation resistance properties of the single layer ethylene propylene materials and has the added characteristic of meeting the IPCEA Flame Test.
Bostrad Single layer - CSPE #14 - 7 strand . 150" dia.
Bostrad Two layer - silicone - CSPE #14 - 7 strand
- 161" dia.
Bostrad Two layer - EPDM - CSPE #14 - 7 strand
- 161" dia.
GR 838 Single layer - CSPE #14 solid
- 180" dia.
GR 853A Single layer - EPDM #18 solid
- 130" dia.
GR 861 Single layer - EPM #18 solid . 125" dia.
GR 789 ,Single layer - CSPE #20 - 7 strand . 123" dia.
0 0
INSULATION RESISTANCE AND INSULATION RESISTANCE CONSTANT Introduction Insulation resistance measurement were made on wires irradiated to total dose of 1 x 108 and 5 x 108 rads by a high energy electron beam. Comparative tests on unirradiated wires were also carried out.
Test Procedure Three 12 foot samples were prepared for each type of insulated wire. One sample remained unirradiated, and the other two were irradiated by a high energy electron beam to total doses of 1 x 10 8 and 5 x 108 rads. After irradiation, the central 10 feet of each sample was immersed in water at 60°F. The insulation resistance was measured after-a 1 minute application of 500 volts DC. The results are shown in Table 1. From these values, the I. R. constants were calculated and shown in Table 2.
TABLE I Typical Insulation Resistance Values for 10 Ft. Samples Values Given in Megohms Compound Radiation Dose (Rads) 0 1 x 10 8 5 x 10 8 Bostrad 7 4.4 x 10 4 2.7 x 104 2.5 x 104 Bostrad 7S 4.0 x 104 6.2 x 10 3 Bostrad 7E 2.7 x 105 2.7 x 105 2.8 x 105 GR 838 1.9 x 10 5 1.0 x 10 5 9.5 x 104 GR 861 9.5 x 10 5 9.4 x 10 5 8.9 x 105 GR 789A 5.4 x 10 3 3.4 x 10 3 GR 853A 1.0 x 10 6 3.4 x 10 5 2.3 x 104
..Not Tested
TABLE Z Insulation Resistance Constant Radiation Dose (Rads)
Compound 0 1 x 10 8 5 x 10 8 Bostrad 7 1,490 910 850 Bostrad 7S 1,280 200 Bostrad 7E 7,900 7,900 8,180 GR 838 4,560 2,400 2,280 GR 861 17,400 17,400 16,300 GR 789A 105 66 GR 853A 17,900 6,080 410
- Not Tested
WATER ABSORPTION CAPACITANCE STABILITY AND DIELECTRIC CONSTANT Introduction Water absorption tests wer,0 performed on wires irradiated to total doses of 1 x 108 and 5 x 100 rads by a high energy electron beam.
Comparative tests on unirradiated wires were also carried out.
Test Procedure Each sample consisted of a 12 foot length of wire with the central 10 feet immersed in water at 75 *C. ,The tests were conducted to IPCEA S-19-81 with capacitance measurements after 1, 7, and 14 days immersion. The insulation resistance was also recorded at these times.
Conclusions The insulation resistance measured after 1 and 14 days immersion are shown in Table 3 for 0, 1 x 108 and 5 x 108 rads. In general, irradiation had very little effect on insulation resistance.
The change in capacitance from 1 to 14 days and from 7 to 14 days is shown in Table 4. The ethylene propylene compounds were the most stable, showing virtually no change in characteristics up to 5 x 108 rads. The CSPE compounds exhibited an increase in the capacitance change with an increase in radiation level.
From the values of capacitance after 1 day immersion, the dielectric constants were calculated by the formula given in IPCEA S-19-8 1. These constants are shown in Table 5. It can be seen that radiation had no effect on the dielectric constant of any material.
10
TABLE 3 INSULATION RESISTANCE (Meg Q/M')
Compound Radiation Dose (Rads) 8 8 0 1 x 10 5 x 10 After I day After 14 days After 1 day After 14 days After I day After 14 days Bostrad 7 0.69 1.38 0.34 0.55 1.2 B Bostrad 7S 3.3 4.5 1.2 6.7 B B Bostrad 7E 460 880 1.55 700 1.5 0.8 GR 853A 1150 1150 1200 3000 2000 6700 GR 861 3000 6500 4500 3000 11000 6000 GR 838 1.11 1.69 1.25 1.2 1.25 1.4 GR 789A 0.49 1.03 0.34 0.74 A A A - No Sample B - Insulation cracked
TABLE 4 CHANGE IN CAPACITANCE Radiation Dose (Rads)
Compound 8 8 1x 10 5 x 10 0
1- 14 days 7 - 14 days I - 14 days 7 - 14 days I - 14 days 7 - 14 days Bostrad 7 +3.0% +2.2% +ZZ.6% +10.5% B B Bostrad 7S +2.5% +1.7% -3.1% +0.5% B B I
Bostrad 7E +I. 2% +1.7% +3.6% +2.3% +46.0% +11.4%
N GR 853A 0% +0.2% +3.0% +4.0% 0% +0.2%
GR 861 +0.9% -0.5% +15.5% +4.0% 0% +2.4%
GR 838 +4. 1% +0.7% +31.2% +4.1% +58.0% +11.8%
GR 789A -1.3% +2.8% +351.5% +87.5% A A A - No Sample B - Insulation cracked 0
TABLE 5 DIELECTRIC CONSTANT Radiation Dose (Rads) 0 1 x 10 8 5 x 10 8 Compound Bostrad 7 (Hypalon) 8.9 10.6 10.5 Bostrad 7S (Silicone & Hypalon) 4. Z 4.1
- Bostrad 7E (EPDM & Hypalon) 3.9 3.6 4.4 GR 853A (EPDM) 3.8 3.2 3.2 GR 861 (EPM) 2.7 2.8 2.9 GR 838 (Hypalon) 8.5 8.7 6.8 GR 789A (Hypalon) 11.7 10.7
- Not tested
D. C. BREAKDOWN OF INSULATED WIRES Introduction Three samples of each wire, 4 feet in length, were irradiated
- by a high energy electron beam to total integrated doses of 1 x 10 and 5 x 108 rads.
Test Procedure After irradiation, these samples were subjected to a d.c.
breakdown test with unirradiated samples tested for comparison.
Approximately 2 feet of each wire was immersed in water, and the voltage was raised at a rate of approximately 1 kv/sec to breakdown.
Each failure was located and examined. The cable O.D. and wall' thickness were then measured at the actual point of failure. The average stress (breakdown voltage divided by wall thickness) and maximum stress was found from the formula: Q)
E = 2V where E = maximum stress dc ln d o V = breakdown voltage dc = conductor diameter dc do = O.D. of cable Conclusions It can be seen that the breakdown stresses of most insulations dropped with increasing radiation dose. The exceptions were the two ethylene ropylene compounds which were unaffected by radiation up to 5 x 10? rads for GR 861 and 1 x 108 rads for GR 853A.
TABLE 6 D.C. BREAKDOWN OF WIRES Radiation Mean Breakdown Nominal Maximum Average Dose Voltage Wall Conductor Stress Stress Compound (Rads) (KV d. c.) (mils) (A. W. G.) (Volts/mil) (Volts/mil)
Bostrad 7 0 8 25 45 #14 995 790 1 x 108 24 45 7 Strand 940 565 5 x 108 13 45 525 415 Bostrad 7S 0 38 45 #14 1335 1065 1 x 108 44 45 7 Strand 1575 1015 5 x 108 8 45 295 190 Bostrad 7E 0 60 50 #14 2080 1275 1 x 108 32 50 7 Strand 1055 650 5 x 108 22 50 745 550 GR 838 0 8 .40 60 #14 1195 800 I x 108 30 60 Solid 935 540 5 x 10 20 60 625 370 GR 789A 0 76 40 #20 3355 1740 1x 108 53 40 7 Strand 2345 1315 5 x 10 19 40 865 480 GR 861 0 178 50 #18 7835 4185 1 x 108 182 50 Solid 7100 3710 5 X 108 190 50 7590 4100 GR 853A 0 63 45 #18 2675 1550 1 x -108 68 45 Solid 2655 1540
FLAME TESTS ON INSULATED WIRES Introduction The flame tests were carried out on single leds and twisted pairs which had been irradiated to total -doses of 1 x 10 and 5 x 108 rads by a high energy electron beam. Comparative tests on unirradiated wires were also carried out.
Tests on Single Leads and Twisted Pairs The single leads were tested to the method specified by IPCEA S-19-81. The results are summarized in Table 7.
All twisted pairs, except one, were tested to the IPCEA method with the addition of the two-lamp circuit between conductors, and in some tests the insulation resistance was also measured. The results are summarized in Table 8.
Conclusions All of those materials which passed this test in the unirradiated state also passed when irradiated; however, a slight degradation was Q noticed in that the irradiated samples burned for a longer time between flame applications. Of those materials which failed, the failures occurred in a shorter time for the irradiated wires.
The twisted pairs that were tested all showed the same trends as the single wires. The only exception was Bostrad 7E which passed this test before irradiation but failed electrically afterwards. Butyl, Silicone and cross-linked polyethylene were included here for information.
There is no doubt that electron irradiation has a deleterious effect on flame resistance of elastomeric insulation. However, this effect is very small, and virtually all specimens-which passed the flame tests before irradiation also passed after.
The wires with the best flame resistant properties were the Bostrad 7S. These leads recovered 60ro of their original I. R.
minutes after flame removal.
16
TABLE 7 SINGLE LEADS TESTED TO IPCEA S-19-81 Sample Indicator Tab Remarks Bostrad 7 irradiated Passed)
Bostrad 7 unirradiated Irradiated sample burned for longer Passed) times between flame applications.
Bostrad 7S irradiated Passed)
Bostrad 7S unirradiated Irradiated sample burned for longer Passed) times between flame applications.
Bostrad 7E irradiated Passed)
Bostrad 7E unirradiated Irradiated sample burned for longer Passed) times between flame applications.
GR 838 irradiated Passed)
GR 838 unirradiated Edges of indicator tab charred Passed) after 90 sec.
GR 789A irradiated Wire burned through after 55 sec.
GR 789A unirradiated Wire burned through after 135 sec.
GR 853A irradiated Failed after 90 sec.
GR 853A unirradiated Failed after 115 sec.
GR 861 irradiated Failed after IZ0 sec.
GR 861 unirradiated Failed after 180 sec.
GR 847C unirradiated Failed after 45 sec.
TABLE 8 TWISTED PAIRS TESTED TO IPCEA S-19-81 Sample Indicator Tab Indicator Lamps Remarks Bostrad 7 irradiated Passed Passed) Irradiated sample Bostrad 7 unirradiated Passed Passed) burned for longer times between flame applications.
Bostrad 7S irradiated Passed Passed) Irradiated sample Bostrad 7S unirradiated Passed Passed) burned for longer times between flame applications.
Bostrad 7E irradiated Passed Failed between 90 and 150 sec.
Bostrad 7E unirradiated Passed Passed GR 838 unirradiated Passed Passed GR 789A irradiated Passed Failed after 100 sec.
GR 789A unirradiated Passed Failed after 45 sec.
GR 853A unirradiated Failed after 240 sec. Failed between 30 and 60 sec.
GR 861 irradiated Failed after 250 sec. Failed between 30 and 90 sec."
GR 861 unirradiated Failed Failed after 30 sec.
GR 847C unirradiated Failed after 130 sec. Failed between 30 and 50 sec.
Silicone unirradiated Passed Failed after 40 sec.
Cross-Linked Polyethylene Failed Failed after 15 sec.
unir radiated 0