ML17199F910
| ML17199F910 | |
| Person / Time | |
|---|---|
| Site: | Dresden, Quad Cities, 05000000, 05000256 |
| Issue date: | 08/25/1986 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML17199F909 | List: |
| References | |
| NUDOCS 8609040352 | |
| Download: ML17199F910 (2) | |
Text
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 ENCLOSURE SAFETY EVALUATION RY THE OFFICE OF NUCLEAR REACTOR REGULATION SPDS ISOLATOR APPROVAL AND CO~PLETION OF SPDS REVIEW COMMONWEALTH EDISON COMPANY IOWA-ILLINOIS GAS ANO ELECTRIC COMPANY DRESDEN NUCLEAR POWER STATION, UNIT NOS. 2 AND 3 QUAD CITIES NUCLEAR POWER STATION, UNJT NOS. 1 AND 2 DOCKET NOS. 50-237/249/254/265
1.0 INTRODUCTION
In order to satisfy the NRC requirements cnncerninq the Safety Parameter Display System (SPDS), Commonwealth Edison Company (the licensee) suhmitted a Safety Analysis Report b.v letter dated December 29, 1983.
The report provided a description and a safety analysis of the SPDS at the Dresden Station, Units 2 and 3 and at the Quad Cities Station, Units 1 and 2. This report did not address the requirement that the SPDS must be isolated from eouipment and sensors that are used in safety systems to prevent electrical and electronic interference.
On June 22, 1984, a letter was sent to CECn which approved continued implemen-tation of the SPDS program but which also included specific questions on isolation devices.
The requested information was received by letters dated August 30, 1984, and October 17, 1984.
The staff held telephone conferences with the licensee on February 27, 1985, November 26, 1985, and on June 19, 1986. These telecons resulted in August 26, '1985, June 4 and 25, 1986 submftta 1 s.
This evaluation addresses the qualification and documentation of the isolators '
used at Dresden and Quad Cities as acceptable interface devices between the Class lE safety-related instrumentation systems and the SPOS *.
2.0 EVALUATION The SPDS at Dresden and Quad Cities is a software packaoe incorporated into the plant computer.
The system orovides the operators,-in a sinnle location, the value of the safety-related variables which directly indicate the status of plant safety functions.
The plant computer is a non-safety-related system and has been isolated from safety-related process inputs by the use of. Acromaq Inc., Series 700 electrical isolation devices.
These isolators have been subjected to 1000 VAC dielectric strenqth tests, have a common mode* noise rejection of 130 dB at 60 Hz, and are enclosed in a sheet metal enclosure which minimizes the effects of externally qenerated interference. The isolators have also passed a seismic qualification test.
They are located in a mild environment, and no further environmental qualification testing is required.
- l ** 't***-
- In addition to the above tests, the Acromag isolators were subjecte~ to the maximum credible fault (MCF) test. The MCF conditions for Dresden and Quad Cities were determined to be 120 VAC (60 Hz) at 15 amps.
This was the maximum amount of both the voltage anrl the current available in the rack that houses the isolator card caqe.
The pass/fail criteria stated that there would be no effect on the input signal as a result of the application of the MCF.
The MCF was applied to the output of the isolator in the transverse mode between output signal plus (+) and minus (*). A recorder with a response time of 1 milli-second was used to monitor the Class lE input of the isolator.
Upon the application of the MCF, the recorder did not indicate any fluctuatibn in the input signal, thus demonstrating the ability of the isolator to iuccessfully isolate output from input.
The Acromaq models were Model 712-L and Model 722-TL-Y.
The plants also used Model 712-H.
A comparison of the electrical schematics of the 712-l and 712-H indicate that the Model 712-H would offer similar isolation capability between signal input and output circuits.
3.0 CONCLUSION
Based on an audit of the information supplied by the licensee with respect to the electrical isolation devices used on the SPOS, the staff has concluded that the Acromaq Series 700 isolators are aoproved devices for isolating the safety-related data channels from the SPOS.
The staff al~o concludes that~
with the above approval of. the isolators, the Dresden and Quad Cities SPDS meet the Co1T1TT1ission's requirements of NUREG-0737, Supolement 1.
4.0 REFERENCES
- 1.
letter dated 12/29/83, E.D. Swartz, CE Co., to H. R. Denton, NRC.
- 2.
Letter dated 6/22/84, D.M. Crutchfield, NRC to D.L. Farrar, CE Co.
- 3.
letter dated 8/30/84, J.G. Marshall, CE Co., to H.R. Denton, NRC~
- 4.
letter elated 10/17 /84, R. Ryback, CE Co., *to H. R. Denton, NRC.
- 5.
Letter dated 8/26/85, J.R. Wojnarowski, CE Co., to H.R. Denton, NRC.
- 6.
letter dated 6/4/86, J.R. Wojnarowski, CE Co., to H.R. Denton, NRC.
- 7.
letter dated 6/25/86, J.R. Wojnarowski, CE Co., to H.R. Denton, NRC.
Principal Contributor:
R. Eckenrode Dated:
Augu~t 25, 1986