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Safety Evaluation Supporting Environ Qualification of safety-related Electrical Instrument Cables Mfg by Continental Wire & Cable Corp
	ML18116A322
Person / Time
Site:	Surry
Issue date:	07/25/1979
From:	; Office of Nuclear Reactor Regulation
To:	;
Shared Package
ML18116A321	List: ML18116A320; ML18116A322;
References
	NUDOCS 7908140467
	Download: ML18116A322 (9)
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO THE ENVIRONMENTAL QUALIFICATION OF SAFETY RELATED CABLE USED BY THE VIRGINIA ELECTRIC AND POWER COMPANY AT SURRY POWER STATION, UNIT NOS. l AND 2 DOCKET NOS. 50-280 AND 50-281 INTRODUCTION Virginia Electric and Power Company (VEPCO) by letter dated September 29, 1978, submitted its proposed qualification test program for determining whether certain electrical instrument cables manufactured by Continental Wire and Cable Corporation will function under environ-mental conditions simulating those expected within the containment of Surry Power Station Units l and 2, during a postulated loss of coolant accident (LOCA) or during a main steam line break (MSLB).

The test program was intended to include irradiation and additional aging of the cable samples which have been in service at Surry for more than seven (7) years, exposure of the cables to a combined steam and chemical spr~y while electrically energized, and a comparison of the physical properties of the samples before and after the environmental exposures.

Separate tests were proposed to be conducted, one to simulate the LOCA conditions and a second to test the MSLB environment.

The sample cable used in the test program was 300V,.'two conductor, No. 16 AWG, stranded with cross-linked polyethylene insulation and.

hypalon jacket (see figure A for details). The test program required seven (7) test samples to be prepared - three for the LOCA test, three for the MSLB test and one for measuring initial physical and electrical properties.

The acceptance criteria for LOCA and MSLB test were established as follows:

A.

Short term for safety system initiation following an incident:

The cable shall be considered acceptable if the current measurement remains between 24 and 26 milliamps during the first five minutes of the test.

B.

Long tenn for monitoring and operator action following an incident:

The cable shall be considered acceptable if the current measurement remains between 22 and 28 milliamps throughout the test.

VEPCO by letter dated December 15, 1978, submitted the test report of the environmental qualification perfonned by Conax Corporation on the Continental Instrument Cable in accordance with the test procedure.

Additional information on the test was submitted by letter dated May 3, 1979.

The cable samples supplied by VEPCO were cut into test samples as shown in Figures Band C.

Three test samples, thermally aged for 60 hours6.944444e-4 days 0.0167 hours 9.920635e-5 weeks 2.283e-5 months at 100°C and irradiated to 20 megarads (MR), were installed in the test chamber, connected, instrumented and subjected to the LOCA environment (temperature/pressure/

chemical spray environment).

The test chamber LOCA temperature profile is shown in Figure D.

Data were collected of the measurements of voltage and current throughout the 48 hours5.555556e-4 days 0.0133 hours 7.936508e-5 weeks 1.8264e-5 months of the test.

Three test samples, thermally aged for 60 hours6.944444e-4 days 0.0167 hours 9.920635e-5 weeks 2.283e-5 months at 100°C and irradiated to 20 kilorads (KR), were installed in the test chamber and subjected to the specified MSLB test environment.

The test chamber MSLB temperature profile is shown in Figure E.

Data were also continuously collected throughout the test period of 48 hours5.555556e-4 days 0.0133 hours 7.936508e-5 weeks 1.8264e-5 months .

DISCUSSION The test procedure and the tests done for qualification of the Continental Instrument Cable followed the general guidelines of IEEE Std. 323-1974.

TEST SEQUENCE The cable samples were thermally aged, irradiated and subjected to steam pressure, temperature and chemical spray as outlined in the approved test procedure.

The test sequence was in line with the sequence of IEEE Std. 323-1974.

AGING All cable samples were subjected to accelerated aging at 60°C for 100 hours0.00116 days 0.0278 hours 1.653439e-4 weeks 3.805e-5 months equivalent to 33 years to simulate their end-of-life condition.

We have reviewed the basis provided by VEPCO letter dated May 3, 1979, for equating this 100 hour0.00116 days 0.0278 hours 1.653439e-4 weeks 3.805e-5 months elevated temperature test to 33 years of operation at expected containment temperatures (at or below 40°C or l04°F) and find the basis acceptable.

MARGIN By comparing the test data and the plant's temperature and pressure pro-files for LOCA and MSLB events, we conclude that adequate margin per IEEE Std. 323-1974 is provided.

(The temperature peak of 420°F during 20 to 90 second interval of the incident was not obtained during the test; however, the test temperature of 350°F was sustained for a period of 15 minutes to compensate for this. This deviation is provided for in the test procedure itself and is acceptable).

RADIATION The thermally aged samples were divided into two batches - one for the LOCA test and the other for the MSLB test. The samples for the LOCA test were irradiated to obtain an integrated gamma dose of 20 MR at l MR/hr_and the samples used in the MSLB test were irradiated to 20 KR at l KR/hr.

Measurements of electrical and physical properties were made in conformance with applicable industrial standards.

The data presented for the test are considered satisfactory for Surry Units l and 2 service conditions.

OPERATION.UNDER NORMAL AND ACCIDENT CONDITIONS The electrical connections made in the tests to keep the samples energized supplying simulated loads during the period when the samples were exposed to simulated environmental conditions are satisfactory.

The review of the continuous readings of the current and voltage of the samples taken during the test show that the currents were within the required limits of the acceptance criteria (one of the three samples in the MSLB test exceeded the acceptance criteria for current. However, measurements taken after the test traced this discrepancy to a decrease in resistance of a variable resistor outside the test chamber.

Conax Corporation 1 s report has conclusively establi_shed that the increased current flow in that particular test sample circuit was caused solely by the resistance decrease in that variable resistor and in no way was a result of any change in the test cable).

Based on this we conclude that all LOCA and MSLB cable samples conformed to the acceptance criteria of the test procedure.

SUMMARY

Based on our review of the test results we conclude that the Continental Wire and Cable Corporation instrumentation cable tested is qualified to perfonn its required functions before, during and following the specified abnormal environmental conditions. The acceptability is on the basis that the tests performed were generally in line with the requirements of Regulatory Guide 1.89 (IEEE Std. 323-1974).

Environmental Consideration We have determined that this action does not authorize a change in effluent types or total amounts nor an increase in power level and will not result in any significant environmental impact.

Having made this determination,

e we have further concluded that this action is insignificant from the standpoint of environmental impact and, pursuant to 10 CFR §51.5(d) (4),

that an environmental impact statement or negative declaration and env i ronmenta 1 impact apprai sa 1 need not be prepared.

Conclusion We have concluded, based on the considerations discussed above, that:

(1) because the action does not involve a significant increase in the probability or consequences of accidents previously considered and does not involve a significant decrease in a safety margin, the action does not involve a significant hazards consideration, (2) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and (3) such activities will be conducted in compliance with the Commission's regulations and will not be inimical to the common defense and security or to the health and safety of the public.

Date:

July 25, 1979

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TYPE OF CABLE:

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.. 45 ~ILS OVERALL HYPAt.ON JACKET.:38 11 OVERALL DIAMETER.

REGION:

. I) NO.IS AWG. COPPER CONDUCTOR.

2) 25 MILS (.025 11

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3) AIR SPAC 0

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4) OVERALL ALUMINUM FOIL SHIELD-2 MILS (.0020 11

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5) OVERALL HYPALON JACKET-65 MILS (.045 11

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6} ASBESTOS BINDING.TAPE 6MILS (.006 11 ).

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