ML20214R681
| ML20214R681 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 03/25/1987 |
| From: | Roberts E EG&G IDAHO, INC., IDAHO NATIONAL ENGINEERING & ENVIRONMENTAL LABORATORY |
| To: | Carrington M Office of Nuclear Reactor Regulation |
| References | |
| CON-FIN-D-6019 EWR-71-87, NUDOCS 8706080254 | |
| Download: ML20214R681 (7) | |
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/NEA Idaho Netforsel Engirseering Laborotory March 25, 1987 Mr. M. Carrington, Program Manager Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D.C.
20555 I
TRANSMITTAL OF " TECHNICAL EVALUATION REPORT (TER), SOUTH TEXAS PRCJECT, UNITS 1 AND 2, ISOLATORS' TEST REPORT,"
(FIN 6019) - EWR-71-87 i
Ref: NRC Form 189, Licensing Action Review for SER Chapter 7 Review for South Texas Project, Units 1 and 2, FIN D6019, June 25, 1986
Dear Mr. Carrington:
Transmitted herewith is the above subject TER.
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This TER documents INEL's evaluation of the applicant's submittals with regard to the isolators' test report. The isolators have been found to be l
qualified for use in Class 1E systems at the South Texas Project, Units 1 and 2.
Very truly yours, E. W. Roberts, Manager NRC Headquarters Support 9p
Enclosure:
i As Stated cc:
J. L. Mauck, NRR-PAEI i
F. Rosa, NRR-PAEI G. L. Jones, DOE-ID J. O. Zane, EG&G Idaho, Inc. (w/o Encl.)
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A PDR
i TEGNICAL EVAIUATICE RIGORP SOUIH TEXAS PinTECT, UNITS 1 AND 2 ISOIATORS TEST REPORT
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BACN3ROUND On July 17,1978 (Ref.1), Houston Light and Power (HIAP) Campany, the applicant for South Texas Project (STP), Units 1 and 2, transmitted a Final Safety Analysis Report (ESAR) to the NRC staff as part of their application for an operati:xJ license (OL). Chapter 7 of the STP ESAR hibes wiuvl and protection system inted.on.
The ESAR states that control signals are derived from protection channels that are isolated fran the cuiuvl channels by isolation amplifiers. The paragraph detailing the isolation anplifiers also hibes faults that could originate in the control dannel and states that the purpose of the isolator is to prevent these postulated faults from affecting the protection' channel.
2 The staff reviewed the STP FSAR and Me==4 the isolation anplifiers with HIAP. In a letter dated June 17,1985 (Ref. 2), HIAP agreed to provide the staff with the isolator test reports. This canmitment was rh'= anted as an Open Item of Section 7.1.4, Soecific Findinos, of the Safety Evaluation Report (SER) NUREG 0781, "Related 1
to the Operation of South Texas Project, Units 1 and 2," dated April 1
1986 (Ref. 3).
i The applicant respcudied to the Open Itsan in a letter dated October 31,1986 (Ref. 4), and included a' summary of the isolator test 1.ey.n. Ls. The NRC staff reviewed the October 1986 submittal and sent a Recuest for Mditional Information (RAI) to HIAP on January 13, 1987 (Ref. 5).
The applicant responded to the'RAI in a letter dated February 19, 1987 (Ref. 6).
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'Ihis Technical Evaluation Report (TER) addma the HL&P submittals regarding these isolators and evaluates the isolators' ability to meet General Design Criterion (GDC) 24 and IEEE Std. 279-1971 requhausait.s for isolation.
EG&G Idaho Inc. assisted the NRC staff in the review of the HL&P subnittals.
II.
DISCUSSION AND EVAIUATICN
'Ihe review criteria for the isolator test ierstG state that the transmission of signals fran Class 1E syctems (i.e., protection system) to non-Class 1E systems (i.e., control systems) shall be through isolation devices and tint these isolation devices shal2. be mvla a part of the Class 12 system. 'Ihe criteria further state that no crwlible failure at tle output (the non-Class ?.E side) of the isolators shall jeopardize the integrity of tlm Class 1E input to the isolator.
'Ihe HL&P response to the Open Item indicated that the following -
isolators w re used at STP Unit 1 and 2:
1.
Energy Incorporated (EI) - Analog Model No. 00798-XX, transformer type isolation barrier and Digital Model No. 01026-17, optical type isolation barrier; usel in the Emergency FxrTsiie Facilities j
Data Acquisition and Display System (ERGADS).
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2.
General Atcznic Ctznpany (GA) - Ccxnmunication Isolation Devices
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(CID) 0357-5200, IAC-24 and IDC-24, all optical type isolation barriers; used in the RM80 Digital Radiation Monitoring System (NMS).
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3.
Cooper Energy System (CES) - Digital isolators <=med cf solid state transmitters; receivers linked by fiber-optic cables; used in the diesel generator control panels.
All three suppliert subjected their isolators to functional and hipot-tests and to a surge withstand capability test. In addition, the isolators were qualified according to IEEE Std. 323-1974, "IEEE Standard for Qualifying Class lE Equignent for Nuclear Power Generating Stations," and IEEE Std. 344-1975, "IEEE R - nded Practices for Seismic Qualification of Class 1E Eqdment for Nuclear Power Generating Stations." 'Ihe isolators are located in a mild envimmait; therefore,10 CFR 50.49, which addresses harsh environments, does not apply.
'Ihe pass / fail criteria for the above testing are that there shall be no evidence of insulation breakdown or flashover, that the device shall maintain all isolation barrier characteristics, and that the device shall pass pre-and post-test functional tests.
Each type of isolator provirlw! by the three suppliers passed the pass / fail criteria. 'Ihis satisfies the requirement that the isolators be made a part of the claca 1E system with which they are associated.
In addition to the testing previously described, the EI and GA isolators were subjected to a maximum credible fault (MCF) test applied to the plus and minus output terminals of the isolators in the transverse mode. 'Ihe MCF voltage / current values to which the isolators could be exposed were 140VAC at a potential current of 20 amps for the EI devices and 140VDC at a potential of 35 amps for the GA devices.
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Fcr the EI devices, the MCF pass / fail criteria state that the devices shall maintain the isolation barrier before, during, and after application of the MCF. For the GA devices, which are used in the IE80 system, the MCF pass / fail criteria state that the signals 1
transmitted within the system shall remain unchanged during and after the application of MCF.
Upon the application of the MCF to the non-Class 1E output of the EI analog and digital isolation devices, the test instrumentation monitoring the Class 1E input circuits did not detect any discernible voltages on the input, indicatint; that the isolation barrier had not been breached and the isolator sm',am fully withstood the challenge of the MCF. Similarly, when MCF was applied to the output terminals of the RM80 system's isolators, no change in the IE80 system signals was detected by the test irstrumentation monitoring the signal.
'Ihe CES isolators use a fiber-optic cable to interface the Class 1E signals with the non-Class 1E systems. Because fiber-optic cables have properties that qualify them as idaal isolators, specific MCF tests are not necessat,(. 'Ihese properties are as follows:
1.
Fiber-optic cables are totally dielectric; therefore, the electrical fault voltage / current canrot propagate frm one end of i
the cable to the other end.
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2.
Fiber-optic cables are not susceptible to electrical interference; therefore, electrical noise, such as elech e tic coupling, connon mode, or crosstr.lk, cannot be induced into or propagate through the cable.
All of the isolators pasM the pass / fail criteria for the MCF tests.
'Iberefore, the requirerrent that the isolators protect the Class 1E circuitry from faults that may appear on the non-Class 1E side of the isolator is satisfied.
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In addition to the isolator test 1.v1.'w, HIAP supplied data showing that the safety systems had been protected frtxn any electrical interference that might be gena. rated att a result of using the electrical isolators. W.is protection was provirlari by using fiber-optic cables, shielded cables, and me6111c shielding and by physical separation of agiir=arit. The applicant also stated that the Class 1E t
side of the isolators is powered by a Class 1E power source, while the non-class 1E side of the isolators is powered by a non-Class 1E power source..
III. (DNCWSIGN Raw on the review of the applicant's submittals with respect to isolation devices, it is concluded,that these electrical isolation devices may be used for interfacing between Class 1E systens and non-Class 1E systems. It is also concluded that these isolation devices meet the requi1.aummh of GDC 24 and IEEE Std. 279-1971.
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- IV.
UmamuMLex 1.
Istter frm HIAP to NRC transmitting HIAP's application for license, dated July 17, 1978.
2.
Istter frm M. R. Wisenburg (HIAP) to G. W. Knighton (NRC),
"Closecut of ICSB Meeting Items," dated June 17, 1985.
3.
Safety Evaluation Report Related to the Operation at South Texas Project, Units 1 and 2, NUREG-0781, dated April 1986.
4.
Ictter tre M. R. Wisenburg (HIAP) to V. S. Noonan (NRC),
" Response to SER Open Item #7 Regarding the Electrical Isolator Test Report," dated M W 2 31, 1986.
j 5.
Istter frm N. P. Iowiambi (NRC) to J. H. Goldburg (HIAP),
" Request for Additional Information of SER Chapter 7 Items -
South Texas Project," dated January 13, 1987.
6.
Istter frun M. R. Wisenburg (HIAP) to U.S. NRC, " Additional Information Concerning Electrical Isolation Devices and Class 1F/Non-Class 1E Control Circuit Interfaces," dated February 19, 1987.
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