ML20247N745

Safety Evaluation Concluding That Isolation Devices Acceptable for Use in Spds,Contingent on Licensee Submittal of Followup Evaluation Verifying That Failure of RIC SC-1302 Was Randomly Deficient Device Prior to Testing

ML20247N745
Person / Time
Site:	Arkansas Nuclear
Issue date:	07/31/1989
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20247N736	List: ML20247N730 ML20247N745
References
NUDOCS 8908030136
Download: ML20247N745 (2)

Text

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                                  %c                                    UNITED STATES
                      !-               n NUCLEAR REGULATORY COMMISSION q                  -{            ; ,E                               WASHINGTON, D. C. 20555
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO THE SAFETY PARAMETER DISPLAY SYSTEM (SPDS) DESIGN ARKANSAS POWER AND LIGHT COMPANY ARKANSAS NUCLEAR ONE, UNIT NOS. 1 AND 2 DOCKET NOS. 50-313 AND 50-368

1.0 BACKGROUND

The Commission's requirements for the SPDS is defined in Supplement I to NUREG-0737, " Requirements for Emergency Response Capability," transmitted in NRC Generic Letter (GL) No. 82-33. Regional workshops on GL 82-33 were held during March 1983. In those workshops, the staff discussed the SPDS requirements and the reviews of.the SPDS. In 1984, the licensee provided_ a safety analysis and description of the SPDS for both units. Since the original submittals did not describe the devices to be used for electrical isolation the staff requested additional information and had several discussions with the licensee in 1985 and 1986. Additional discussions and a meeting were held in 1988. By letter dated June 30, 1988 the licensee responded to a request for additional information and committed L to evaluate the manufacturers' (Rochester Instrument Systems) testing for L applicability to Arkansas Nuclear One (ANO) and perform additional testing if necessary. By letter dated February 28, 1989 the licensee submitted their SPDS isolation device test results. l This evaluation addresses the qualification and documentation of the isolators as acceptable interface devices between Class IE instrumentation and the l Hon-Class 1E SPDS at ANO. 2.0 EVALUATION 1 The SPDS is a Non-Class 1E computer based system that performs data acquisition and signal processing for normal and abnormal plant monitoring. Inputs are a provided from Class IE systems and therefore must be isolated to prevent a i fault in the Non-Class 1E system from propagating to the IE system. The licensee identified three devices that are used for SPDS Isolation: Energy Incorporated Model 993-4 ) Foxboro Model 2AO-VAI Rochester Instrument Systems 50-1302 l For ANO, the licensee has determined that the maximum credible fault (MCF) is 120VAC 9 20 amps. The Energy Incorporated 993-4 was tested to 480VAC 9 10 amps. The staff finds-that the testing encompasses the maximum credible fault and is acceptable. The Foxboro 2AO-VAI has been tested in excess of 120VAC 9 20 amps and is acceptable. e90soso136 890731 3 DR ADOC.K 0500

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t The Rochester Instrument Systems SC-1302 required testing to demonstrate that it could withstand the MCF. In- the testing results submitted in the February 28, 1989 letter the licensee concluded that the testing demonstrated that this device is suitable for use in.the SPDS isolation. When the MCF was applied in the transverse mode to the Non-Class 1E output the voltage excursion on the Class IE side was within acceptable limits and the isolation integrity of the device was maintained. Internal fuses were jumpered. The result of the MCF on the power supply input was also measured. Of the four units tested three had no significant current change while one unit had a significant change which kept increasing until it blew a two amp fuse (71ma initial pretest value) after one and one-half hours. The licensee found that the initial current draw was significantly larger (50%) than the other devices and was probably a faulty device. An evaluation of the applications by the licensee indicated that this larger current draw would not impact any other circuits. The licensee is performing a follow-up evaluation and has verbally committed to provide the results to the staff.

3.0 CONCLUSION

S Based on the staff's review of the licensee's submittals, including testing results, the staff finds these devices to be acceptable for use in the AND SPDS. This finding is contingent upon the licensee submittal of the follow-up evaluation of the RIS 50-1302 which clearly demonstrates that the device which failed was a randomly deficient device prior to testing. Dated: July 31, 1989 Principal Contributor: J. Stewart i i l ___-__ -}}