Characteristic Features of Radiation Resistant Flame Resistant, Chemical resistant, halogen free, low fume, Low smoke Flexible (solid) low smoke and low flame, Safety class IE Power cable/control cable /instrumentation cable Supplied to institutes at PAEC
Extensive testing was carried out on trial samples and the products delivered to institutes at PAEC to ensure our products meet international standards in terms of mechanical, thermal, electrical and radiation resistance. Outlined next is a brief account of the tests performed.
In this context rather than compare the mechanical properties of our cables with Radox 3 core wire (supplied by NCC and imported from abroad), the conformity of the 4 core produced by ASAS cables with International standards for polyolefins was sought as a goal. In Cable test reports enclosed entitled Cable test report are presented tests of mechanical properties, tensile strength at break and elongation % at break of Multi Core wires conducted at Newage cables Ltd, Quality Assurance Department under supervision of Manager Quality Assurance of the testing laboratory. All the properties are superior to the expected performance for polyolefin insulation and sheath.
Key Achievement:
The demonstrated elongation of 150 to 180% of the insulation and resultant higher flexibility was a positive shield against embrittlement induced by aggressive corrosive chemicals environment and high radiation.
The Eb demonstrated by the modified formulation was 190 to 240 % and it was envisaged that the same would permit to produce 30 core wire of the desired outer diameter, remarkable flexibility while keeping all other parameters intact. Young's Modulus is another measure of the flexibility of any wire lower the value higher the flexibility. A transition of Young's Modulus from 2.35 - 2.9 range to 1.61 has resulted from the incorporation of the new elastomer and choice of stabilizers conferring higher elasticity.
According to the supply order by NCC for the ASAS 4 core wire, the wire insulation and jacket was expected to pass Underwriter Laboratory test UL 94 V0 which necessitates that the insulation/sheath may catch fire on exposure to flame but the flame should extinguish within 30 seconds after being alight and should not drop any residue to start secondary fire.
Superior Performance:
Far superior burning behavior was displayed by ASAS 4 Core, ASAS 10 Core and ASAS 30Core (both insulation and jacket) which did not catch fire at all on exposure to flame for 15 seconds repeatedly at interval of 15 minutes. Thus these conform to international standard IEC 60332-1.
Needless to state when the wire does not catch fire, the generation of any smoke is out of question. This fire safety character speaks amply in favor of this wire as excellent choice or alternative to imported wires. Furthermore wire meets flame propagation test, circuit integrity test, smoke emission test and limit of oxygen index test. (see Annexure 2)
The wire insulation demonstrated excellent electrical properties (as recorded in Table 1) and these were in conformity with (or superior to) international standards IEC60 22/860502-1.
Detrimental influence exerted by exposure to aggressive nitric acid and corrosive TBP is a matter of critical importance and needs to be estimated to assess the long term stability of the insulation and jacket over prolonged period. Impairing of mechanical properties namely tensile strength and elongation at break before and after exposure to the attacking vapors emanating from HNO3 and TBP would be reflected by the loss of these properties. Real exposure will take long time and accelerated ageing is thus the reasonable estimate of the damage expected to occur.
Test Results:
As orally communicated from NCC lab, separately 4 Core ASAS wires and jackets were dipped in the same chemicals for 72 hours and showed no visual effects of deterioration or cracks on surface.
Conclusion: From the results it is evident that whereas mechanical properties of imported Radox 3 Core insulation and jacket are less compromised, the mechanical properties of Radox 10 Core jacket and insulation are drastically reduced. On the other hand, the properties of insulation and jacket of 4 Core ASAS showed minor loss, concluding that these were not influenced greatly by exposure and are fairly stable in the specific environment.
In general nuclear power cable and I&C wires and cables are tested for assessing any detrimental influence of radiation on wires or cables by exposing these to 50 M rads and 100 M rads successively in Japan and America. Adopting a specially designed process of exposure, designed by author of this report several years ago for giving high doses in short period of time, the wires were exposed to 100 Mrads at PARAS (certificate attached) and no visual impairment or crack on the surface of wires or jackets was observed.
Radiation Test Outcome:
The values after irradiation exhibited small increase in Tb presumably due to crosslinking a phenomenon which has been observed previously. Elongation at break percent was partially reduced but was still within the permitted level of retention of 50% of the original value.
These tests amply demonstrate the superior properties exhibited by fire resistant cables produced by us. All these tests have been conducted by Western European test labs and under conditions much are more aggressive than encountered routinely.
(Copy attached as Annexure 2)
Multicore power cables produced by ASAS cables not only meet the international standard requirement but in many aspects are also superior to the wires imported by NCC and tested along with our product. In terms of exposure to radiation, 40 years exposure to 30 or so m Sievert only culminates in accumulative exposure of 1 Mrad or so whereas our wires have been exposed to 100 Mrads and the mechanical properties tested show desired retention of these properties in accordance with the international standards.
Extraordinary flexibility and higher elongation at break permits quite rough handling and promises least embrittlement on ageing. Testing of samples at elevated doses of radiation is presently underway. Furthermore flame resistant class to which our cables belong demonstrate excellent performance of maintaining circuit integrity under fire conditions and under fire and water as described appropriately in text.
