ML13330B286

Forwards Addl Info Re Electrical Isolation Devices to Be Used in Util SPDS Design Per Rf Dudley 870810 Request

ML13330B286
Person / Time
Site:	San Onofre
Issue date:	04/01/1988
From:	Medford M Southern California Edison Co
To:	NRC Office of Administration & Resources Management (ARM)
References
NUDOCS 8804070310
Download: ML13330B286 (13)

Text

Southern California Edison Company P. 0.

BOX 800 2244 WALNUT GROVE AVENUE ROSEMEAD, CALIFORNIA 91770 M.O.MEDFORD TELEPHONE MANAGER OF NUCLEAR ENGINEERING (818) 302-1749 AND LICENSING April 1, 1988 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555 Gentlemen:

Subject:

Docket No. 50-206 Safety Parameter Display System (SPDS)

Electrical Isolation Devices San Onofre Nuclear Generating Station Unit 1

Reference:

Letter from R. F. Dudley, (NRC) to K. P. Baskin (SCE) dated August 10, 1987 regarding SPDS Isolation Devices In response to the staff's review of SCE's submittal dated March 17, 1987 regarding the subject topic, the referenced letter requests SCE to submit additional information regarding the electrical isolation devices that will be used in the design of the San Onofre Unit 1 Safety Parameter Display System (SPDS).

The enclosure to the referenced letter identified specific information necessary to evaluate the acceptability of SPDS isolation devices. At present, SCE plans to utilize one or more of the following types of isolation devices in the design of the San Onofre Unit 1 SPDS:

1) Foxboro Voltage-to-Current Converter

2) Foxboro Contact Output Isolation Device

3) Consolidated Controls Corp Isolation Relay 8N13 The requested information for each of these isolation devices is provided in the enclosure to this letter. In the event the final design of the SPDS requires the use of isolation devices other than those listed above, the appropriate test data to demonstrate qualification will be provided to you. If you have any questions or require additional information regarding the enclosure, please let me know.

Very truly yours, 8604070310 680401f]

PDR

ADOC, 0o5000206 P

PDR Enclosure cc: J. B. Martin, Regional Administrator, NRC Region V F. R. Huey, NRC Senior Resident Inspector, San Onofre Units 1, 2 and 3

ENCLOSURE SONGS 1 SPDS ISOLATION DEVICES The following information is provided in response to the NRC's letter dated August 10, 1987. Responses to each of the questions for the three types of isolators that may be used in the SONGS I SPDS are provided below.

1. For the type of device used to accomplish electrical isolation, describe the specific testing performed to demonstrate that the device is acceptable for its application(s).

This description should include elementary diagrams when necessary to indicate the test configuration and how the maximum credible faults were applied to the devices.

1)

Foxboro Voltage-to-Current Converter part number 2AO-VAI modified per ECEP 9206 to become a Voltage-to-Voltage Converter.

Response

Three isolation tests were performed on the output of the 2AO-VAI.

All three tests were performed to ensure the 2AO-VAI would provide proper isolation during a seismic event. The three tests were:

1.

Both outputs grounded.

2. 600 VAC applied between both output leads and ground.

3. 600 VAC applied between both output leads.

See Figure 1 for test configuration.

2)

Foxboro Contact Output Isolation Device part number 2AO-L2C-R

Response

The following tests were performed on the output of the 2AO-L2C-R in conjunction with seismic tests:

Input A shorted; input D open; outputs A&D monitored with contact chatter monitors capable of detecting 100 micro-second opening or closure; both A&D outputs switched during Operating Basis Event (OBE) and Safe Shutdown Event (SSE) tests; 600 VAC applied to output B for 10 seconds during one SSE test.

See Figure 2 for test configuration.

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3)

Consolidated Controls Corp. (CCC) Isolation Relay part number 8N13

Response

During qualification of the relay to IEEE 323-1974, it was assessed that the relay had three safety-related components subject to failure due to aging. The components that were tested are socket KK251A and relays KGU431B and KGU431D.

1. Socket KK251A Test (CCC Report KAM7399/3 Sh. 3)

a. Insulation test between terminals Terminals 6 and 7 were connected together as were 1 through 5 and 8 through 12. A HYPOT voltage of 1700 VRMS was maintained between these two sets of terminals for 60 seconds. This test was conducted under room ambient conditions. No evidence of current leakage or insulation breakdown was apparent in any of the samples.

b. Insulation test from terminals to ground plane All terminals (1 through 12) were connected together and the relay socket was mounted to a sheet of steel. A HYPOT voltage of 1700 VRMS was established between the connected terminals and the steel mounting plate. This voltage was held for 60 seconds at room ambient. Again, there was no evidence of leakage or breakdown in any of the test samples.

2. Relays KGU431B and KGU431D (CCC Report KAM7399/5 Sh. 5) 1700 VRMS was applied from coil to contacts and from contacts to frame.

2. Data to verify that the maximum credible faults applied during the test were the maximum voltage/current to which the device could be exposed, and define how the maximum voltage/current was determined.

1)

Foxboro Voltage-to-Current Converter

Response

2AO-VAI Test Results

1. 2AO-VAI Output Terminals Grounded Neither channel of the 2AI-I2V Current-to-Voltage Converter which fed the 2AO-VAI Voltage-to-Current converter shifted more than 0.5% when one channel of the 2AO-VAI's output was grounded. Also both channels of the 2AO-VAI functioned properly after the test was completed. Refer to Figure 3 for oscillograph recording of 2Al-I2V outputs.

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2. 600 VAC Between Output.and Ground Both the 2AO-VAI and 2Al-I2V remained operational during this test. There was some ac feedthrough to the 2Al-I2V. Refer to Figure 4 for recordings.of outputs.

3. 600 VAC Across the Output Leads The application of 600 VAC across the output terminals of Section A of 2AO-VAI produced the following damage to the unit:

a. Circuit foil from the + output lead connection to 39 opened.

b. Circuit foil from the -

output lead connection to 314 opened.

c. Resistor R32 (402, +3%,

6 W) opened.

d. Capacitor C17 (6.8 uF tantalum) opened.

e. Capacitor Cl1 (4.0 uF polycarbonate) shorted.

f. Diodes CR19, 20, 21, and 22 (Type 1N4447) opened.

No damage occurred to Section B or to the 2Al-I2V Current-to-Voltage converter due to the application of the test voltage to Section A. Refer to Figure 5 for the 2Al-I2V output recordings.

The applied voltage, 600 VAC, exceeds the highest voltage which will be applied to the 2AO-VAI voltage-to-current converters. The converters are installed inside a seismically qualified cabinet with other logic modules.

These modules and the converters are powered from -15 VDC and

+15 VDC Foxboro power supplies. The input and output voltages do not exceed those of the power supply.

2)

Foxboro Contact Output Isolation Device

Response

2AO-L2C-R Test Results

1. Operating Basis Event (OBE) Test Did Contacts Chatter During Test Plane of Output Output Was Unit Functional Vibration A

B After Test Front-to-Back No No Yes, all outputs Back-to-Front No No Yes, all outputs Left-to-Right No No Yes, all outputs Right-to-Left No No Yes, all outputs

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2. Safe Shutdown Event (SSE) Test Did Contacts Chatter During Test Plane of Output Output Was.Unit Functional Vibration A

B After Test Right-to-Left Yes Yes Yes, all outputs Left-to-Right No No Yes, all outputs Back-to-Front No No Yes, all outputs Front-to-Back Yes Yes Yes, all outputs Although contact chatter did occur on two planes of vibration, the unit remained functional. It is also noted that the Foxboro SSE response spectra are higher than the SONGS 1 DBE response spectra. The SONGS 1 DBE response spectra are lower than the Foxboro OBE response spectra. Therefore, no contact chatter would be expected for a SONGS 1 DBE.

3. Both outputs were operated during one OBE and one SSE to ensure proper operations during seismic tests.

The applied voltage, 600 VAC, exceeds the highest voltage which will be applied to the 2AO-L2C-R contact output isolator. The isolators are installed in a seismically qualified cabinet with other logic modules.

These modules and the isolators are powered from -15 VDC and + 15 VDC Foxboro power supplies. The input voltage levels do not exceed those of the power supplies.

3)

Consolidated Controls Corp. Relay

Response

CCC Isolation Relay Test Results The components performed their required function and withstood the 1700 VRMS isolation test.

The applied voltage, 1700 VRMS, exceeds the highest voltage which will be applied to the CCC isolation relays.

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3. Data to verify that the maximum credible fault was applied to the output of the device in the transverse mode (between signal and return) and other faults were considered (i.e., open and short circuits).

1)

Foxboro Voltage-to-Current Converter

Response

The fault was applied per Item 1.1 above. This fault is the maximum credible fault which the device could be subjected to.

See Item 2.1 for test results.

2)

Foxboro Contact Output Isolation Device

Response

The fault was applied per Item 1.2 above. This fault is the maximum credible fault which the device could be subjected to. See Item 2.2 for test results.

3)

Consolidated Controls Corp. Relay

Response

The fault was applied per Item 1.3 above. This fault is the maximum credible fault which the device could be subjected to. See Item 2.3 for test results.

4. Define the pass/fail acceptance criteria for each type of device.

1)

Foxboro Voltage-to-Current Converter

Response

The 2AO-VAI performed its Class lE function during and after the tests. The acceptance criteria were that the device prevent the 600 VAC from damaging the input circuit of the module or from affecting the shared channel or power supply.

2)

Foxboro Contact Output Isolation Device

Response

The acceptance criteria were that the 2AO-L2C-R prevent the 600 VAC from damaging the input circuit of the module or from affecting the shared channels or power supply.

3)

Consolidated Controls Corp. Relay

Response

Acceptance Criteria

1. Socket KK251A

-Minimum dielectric strength of 1700 VRMS, (including margin) measured between terminals 6 and 7 (connected) and all other terminals and any terminal to a steel mounting plate. The potential shall be applied for one minute, minimum, at room ambient. The acceptance criterion was that there be no evidence of breakdown.

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2.

Relays KGU431B and KGU431D Minimum dielectric strength of 1700 VRMS, (including margin) measured between coil and contacts, and from contacts to frame. The potential shall be applied for one minute minimum,,at room ambient. The acceptance criterion was that there be no evidence of breakdown.

5. Provide a commitment that the isolation devices comply with the environment qualifications (10 CFR 50.49) and with the seismic qualifications which were the basis for plant licensing.

1) brrent Converter

Response

The Voltage-tohCurrent converter is fully qualified in accordance with IEEE Standards 323-1974 and 344-1975.

2) ot IolationDevice

Response

The 2AO-L2C-R is qualified in accordance with IEEE Standards 323-1974 and 344-1975.

3)

Consolidated Controls Cor.

Relay

Response

The isolation relay 8N13 is fully qualified in accordance with IEEE 323-1974 and IEEE 344-1975.

6. Provide a description of the measures taken to protect the safety systems from electrical interference (i.e., Electrostatic Coupling, EMI, Common Mode and Crosstalk) that may be generated by the SPDS.

1)

Foxb it Converter

Response

The 2A0-VAI modules are designed with filtering to prevent coupling of unwanted interference. The components within operate at low voltage and are designed to minimize the generation of interference. The impact circuits are designed for individual environments to minimize the effects of EMI and electrostatic coupling by proper signal shielding.

2)

FAoCotacthOtlut Isolation Device

Response

The relay outputs are unaffected by electrical interference.

3)

Consolidated Controls Cor.

Rela

Response

The relay outputs are unaffected by electrical interference.

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7. Provide information to verify that the Class 1E isolator is powered from a Class 1E source.

1)

Foxboro Voltage-to-Current Converter

Response

The 2AO-VAI is powered from Foxboro Power Distribution modules which are fully qualified in accordance with IEEE Standards 323-1974 and 344-1975, and are powered from SONGS 1 safety-related power supplies.

2)

Foxboro Contact Output Isolation Device

Response

The 2AO-L2C-R is powered from Foxboro Power Distribution modules which are fully qualified in accordance with IEEE Standards 323-1974 and 344-1975, and are powered from SONGS 1 safety-related power supplies.

3)

Consolidated Controls Corp. Relay

Response

The 8N13 isolation relays are powered from SONGS 1 safety-related power supplies.

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0 Figure 1 Seismic Test Setup 2AO-VAI ECEP 9206 Vol tage-to-Current Converter To 2 AMP 2AX4OPlO Supply

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15

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+15 INPUIT A

OUP A1 Curren Cource 2AI-12V 2A-A A

~2AO-VAI INPUT a V ac V ac

Figure 2 Seismic Test Setup 2AO-L2C-R Contact Output Isolator 00 V ac 0 -+

0 OUTPUT B ontact INPUT A OUTPUT A hatter SW 4

onitor 0

Contact SW INPUT D Chatter OUTPUT D Monitor

Figure 3 Graphs of High Voltage Test No. 1 Channel A Chart speed 5 awn/sec.

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Figure 4 Graphs of High Voltage Test No. 2 1007 Channel A a

A0Z Chart speed 5 an/sec.

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Figure 5 Graphs of High Voltage Test No. 3 Channel A 100C Chart speed 5 m/s 50s 100.-Chat pe 2 5 m/sec.

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