ML20147D972
| ML20147D972 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 02/26/1988 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20147D868 | List: |
| References | |
| RTR-NUREG-0737, RTR-NUREG-737 NUDOCS 8803040215 | |
| Download: ML20147D972 (2) | |
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SUPPLEMENTAL SAFETY EVALVATION THREE MILE ISLAND NUCLEAR STATION, UNIT 1 SAFETY PARAMETER DISPLAY SYSTFM RACKGD.0VND To satisfy NRC requirements concernino the Safety Parameter Display System (SPDS),GPitNuclearCorporation(GPUN),thelicenseefortheThreeMileIsland Nuclear Staticn Unit 1 (TMI-I), submitted a Safety Analysis Report (SAR) by letter dated April 30, 1984 (Ref. 1).
Based on an analysis of the SAR and on additional requests for infomation, a Safety Evaluation Report (SER) was issued by the staff on December 23, 1985 (Pef. 2).
In this SER, the staff approved the isolators used at TMI-1, with the exception of the Rochester Instrument Systems (RIS) Model 5C-1302 isolator.
This isolation device had not been tested by applying the maximum credible fault (MCF) to the output of the isolator in the transverse mode.
The staff also requested GPUN to provide an updated list of the Class 1E interfaces with the SPOS.
The cualification of the RIS isolator is stated to be an open item in Section i
III-E in the December 1985 SER. The licencee comitted to address the adequacy i
of the isolator by testing for MCFs applied to the output of the isolator in the transverse mode.
II. DISCUSSION AND EVALUATION In response to the request made in the SER, the licensee forwarded an updated list of the Class 1E si April 25,1986 (Ref. 3)gnals that interface with the SPDS by letter dated The submittal listed the SPDS paraneters and the type of isolation device used to isolate the parameters from the SPDS. The void fraction instrumentation was also listed. This instrumentation is isolated from the SPDS by RIS Model 1302 isolators located in the pump power monitoring system.
By letters dated March 9, 1987 (Ref 4) and August 18,1987 (Ref. 5), GPUN forwarded a test report and a clarification that addressed the test procedure, configuration, acceptance criteria, and results of the tests performed on the RIS Model 130? isolation devices. The tast report contained a sketch of the i
j reactor coolant pump power monitor circuit that showed the actual usage of the RIS Model 1302.
The test report stated that the MCF voltage / current conditions for this isolator were 120 VAC at a potential of 20 amps.
The MCF was applied to the non-Class-1E output terminals of the isolatnr and ground and to the output of 2
i the isolator in the transverse mode, that is, directly between the plus and minus output terminals of the isolator.
4 P
l
I' 2
l The test instrumentation monitoring the Class 1E input of the isolator l
detected voltage spikes on the input of very low magnitudes (65 millivolts and l
1ess) and of very low durations (670 micro-seconds or less) when the MCF was applied between the output terminals and ground. These spikes were not of any significance and did not have any effect on the Class 1E input circuitry.
Upon application of the fault to the output of the device in the transverse mode, the test circuitry instrumentation did not detect any AC voltage procaqating through the isolation barrier. This indicated that the barrier had withstood the challenge of the MCF and had protected the Class 1E input from faults that could develop on the non-Class 1E side of the device.
The input resistor was damaged by the heat from the MCF, however, the change in resistance value had no effect on the Class IE circuitry for this specific application.
r III. CONCLUSION The test performed by the licensee demonstrated the ability of the RIS Model i
50-1302 isolation devices to effectively stop the propagation of the MCF from output to input and to adequately protect the Class IE inputs for the specific applications at THI-1.
The staff concludes that these devices may be used as electrical isolation devices between Class IE sionals and the SPDS.
The staff also concludes that this requirement meets the Comission's requirements in NUREG-0737, Supplement 1.
This resolves the SPDS confirmatory item with respect to the RIS Mode 50-1302 isolation devices, as described in the SER for the TMI, Unit 1 SPDS.
IV.
REFERENCES 1.
Letter, H. D. Hukill (GPUN) to D. G. Eisenhut (NRC), "Safety Parameter Display Systen NUREG-0737 (Item I.D.?)," April 30, 1984 2.
Letter, J. F. Stolz (NRC) to H. D. Hukill (GPUN) Three Mile Island Unit 1 Safety Parameter Display System," December 23, 1985.
3.
Letter, H. D. Hukill (GPUN) to J. F. Stoir (NRC)
"TMI-1 Safety Parameter Display Systen - Response to NRC Concerns," April 25, 1986.
4 Letter, H. D. Hukill (GPUN) to U. S. HRC, "Safety Parameter Display System - Isolation Device Test Pesults " March 9,1987.
5.
Letter H. D. Fukill (r, PUN) tn U. S. NRC, "Safety Parameter Display System Isolation Device - Reactor Coolant Pump Power Monitors,"
August 18, 1987.
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