ML20033B784

Forwards Safety Evaluation & Technical Evaluation of Review of Instrument & Station Ground Grid Sys.Info Submitted Re Noise & Isolation Testing of Reactor Protection Sys Acceptable

ML20033B784
Person / Time
Site:	Davis Besse
Issue date:	10/29/1981
From:	Stolz J Office of Nuclear Reactor Regulation
To:	Crouse R TOLEDO EDISON CO.
References
NUDOCS 8112020136
Download: ML20033B784 (3)

Text

e' October 29, 1981

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!!r. Richard P. Crouse IE-3 3-g

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Vice President, fluclear ACRS-10 3

Toledo Edison Company TED

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Dear ifr. Crouse:

EBlackwood H0rn3tein By letters dated January 11, 1973, htvember 10, 1980 and liarch E4,1981, you submitted information coteerning noise and isolation testing of the Davis-Besse reactor p.otection system as required by license condition 2.C.(3)(k). We have complated our review of this information and findl your actions acceptable. Our Safety Evaluation Report (SER) and-its associated contractor Te:hni al Evaluation l Report (TER) are provided as Enclosure 1.

By letter dated flovember 4,1980, you-provide [results of your aulysis and testing for inadvertent ground ties betwpan the'imtrument and station ground gr~id systems.' This was in rasponse to Cur request dated Septenber 26, 19777 We find your submittQs to acceptably resolve our concerns in this area. Our SER and associated contractor 'TER are l

provided as Enclosure 2.

Based upon our SER's, we consider that the above mentioned-subjsets are closed.

Sincerely,

'03ICIAL SICE7

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i John F. Stolz, Chief Operating Reactors Branch #4 Division of Licensing t

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0.S. Nuclear Reg'ulatory Commission Resident Inspector's Office The ClevelandxElectric v

111uminatingNompand 5503 N. State Route 2-a i

Oak Harbor, Ohio 43449 P. O. Box 5000 x.-

Cleveland, Ohio 44101

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,, 7;i-Mrs. Julia Baldwin, Librarian Gerald Charnoff,',-Eg.

Government Doctaents Collection.

Shaw,7 Pittman,Potts l

William Carlson Library University of Toledo.

and Trowbridge 4

1800 M Street, N.W.

2801 W. Bancroft Avenue Washington, D. C.

20036 Toledo, Ohio 43606

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Leslie Henry, Esq.

Fuller, Seney, Henry and Hedge 300 Madison Avenue Toledo, Ohio 43604 Regional Radiation Representative.

EPA Region V.

230 South Dearborn Street Mr. Robert B. Borsum s

Babcock-& Wilcox Chicago, Illinois 60604 Nuclear Power Generatio~n Division Suite 420,'7735 Old Georgetown Road Bethesda,Naryland -20014 Ohio Department of Health

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ATTN: Radiological Health 4

Program Director P. O. Box 118 i

President, Board of Cou ColurcSus, Ohio 43216 Co nissioners of Ottawa Cour.ty

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Attorney General a

Departcent of Attorney General 30 East Broad Street

.i Columeus, Ohio 43215 Harold Kahn, Staff Scientist Power Siting Commission 1

361 East Broad Street

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Columbus, Ohio 43216 Mr. Rick Jagger Industrial Commission State of Ohio 2323 West 5th Avenue Columbus, Ohio 43216 Mr. Ted Myers Manager, Nuclear Licensing Toledo Edi' son Company Edison Plaza 300 Madison Avenue

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x to ltr. dtd.10/29/81-SAFETY EVALUATION PEPORT INSTRUMENT AND STATION GROUND GRID SYSTEMS q

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Introduction In 'a letter dated September 26, 1977, we requested Toledo Edison Company to analyze and test the instrumentation systems at the Davis Besse Nuclear Power Station, Unit 1, to identify and correct.

y anyjinadvertent ties between the instrument and stat on ground grid i

systems and also to report any abnormalities during normal instru-nuntation monitoring.

By letter dated November 4,1980, Tolede Edison Company submitted the results of their analysis and testing for inadvertent ground ties.

I Eval ua tion Tests were conducted to meet the NRC criteria with concentration on the safety systems.

Initial tests indicated several ground ties were present. Suppleraental tests were then conducted to isolate and correct the ground ties.

The inadvertent ties present were in nne channel of the safety features actuation system (SFAS) and in the four channels of the reactor protection' system (RPS). Supplemental tests on each channel isolated.the ground tie so as to determine whether the tie was in accordance with the design criteria or not. An. individual maintenance

. work order (MW0) was the generated to correct each inadvertent ground tie which did not meet the des'gn criteria.

We find the above analysis and testing to be acceptable.-

i Conclusion Based on the information submitted by Toledo Edison Company for the Davis Besse Nuclear Power Station, Unit 1, we conclude that:

l (1) An analysis and tcsting of the groud grid systems has l

been conducted per NRC criteria.

c (2) The ground ties found in the ground grid systems which do not meet design criteria have been isolated and I

corrected.

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JNTERIM REPORT IIRC TAC No(S)._10996

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REPORT No.

UCID - xxxx C0hTRACT PROGRAM OR PR(1)ECT TITLE:

ELECTRICAL, INSTRUMENTATION, AND CONTROL SYSTEM SUPPORT SU3 JECT OF THIS DOC TENT:

TECHNICAL EVALUATION OF THE STATION AND INSTRUMENT GROUND GRID SYSTEMS AT THE DAVIS BESSE NUCLEAR POWER STATION, UNIT 1.

IYPE OF DOCUMENT:

INFORMAL REPORT AUTHOR (S):

J/JiES C. SELAN DATE OF DOCUMENT:

JUNE 29, 1981 RESPONSIBLE NRC It0IVIDUAL AND NRC OFFICE OR DIVISION:

l PAUL SHEMANSKI - ONRR This doew:ent uas prepared primarity for prclininary or internat use.

It has not received fuit review and approvat. Since there may be substantive l

cr:anges, this docw:ent should not be considered finat.

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Prepared for the U.S. Nuclear Regulatory Comission l

Washington, D.C.

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,9 Under DOE Contract No. BLR201904031 yuk (y

NRC TIN No. 0250

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INTERIM REPORT unumr eicuom.

La wrence Liverr~ ore National Lavoratory P. O. Bo t 4 $

MZrCary, Nevada 89023

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SELECTED ISSUES PROGRAM TECHNICAL EVALUATION OF TIJE STATION AND INSTRUMENT GROUND CRID SYSTEMS AT THE DAVIS RESSE NUCLEAR POWER STATION UNIT 1 (Docket No. 50-346)

June 29, 1981 By James C. Selan Lawrence Livermore National Laboratory, Nevada

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ABSTRACT Tftisreportdocumentsthetechnicalevaluationofthestation I

and instrument ground grid systems at the Davis Besse Nuclear Power Station, j

i Unit 1.

The evaluation is to determine that there are no inadvertent ties I

between the instrunent and station ground grid systems and that any identified inadvertent ties be corrected and to assure that the installation meets design criteria.

The information submitted by the liebnsee indicates that there are

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no inadvertent ties between the station and instrument ground grid systems and that the installation meets design criteria, l

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FOREWORD This report is supplied as part of the Selected Electrical, Instrumentation, and Control Systems Issues Program being conducted for the U. S. Nuclear Regulatory Commission, Office of Nuclear Reactor Regulation, Division of Operating Reactors, by Lawrence Livermore National Laboratory, Engineering Research Division of the' Electronics Engineering Department.

The U. S. Nuclear Regulatory Commission funded the work under the authorization entitled " Electrical, Instrumentation and Control System Support," B&R 20 19 04 031, FIN A-0250.

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n TABLE OF CONTENTS Page 1

1.

INTRODUCTION.

1 2.

EVALUATION 1

2.1 Testing 2

2.2 Analysis 2

3.

CONCLUSION

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TECHNICAL EVALUATION OF THE STATION AND INSTRUMENT GROUND CRID SYSTEMS AT THE DAVIS BESSE NUCLEAR POUER STATION UNIT l' I

I (Docket No. Su-346)

James C. Solan Lawrence Livermore National Laboratory, Nevada j

1.

INTRODUCTION

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In a letter dated September 26, 1977 [Ref. 1], the Nuclear Regulatory

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Commission (NRC) requested Toledo Edisen Company, the licensee, to analyze and.

test the instrumentation systems at the Davis Besse Nuclear Power Station, Unit 1, to identify and correct any inadvertent ties between the instrument and station ground grid systems and also to report any abnormalities during normal instrumentation monitoring.

By letter dated November 4, 1980 [Ref. 2], Toledo Edison Company submitted the results of their analysis and testing for inadvertent ground ties.

The purpose of this report is to evaluate the licensee's submittal with respect to the NRC criteria and present the reviewer's conclusion on the acceptance of the installation systems to meet design criteria.

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EVALUATION 2.1 TESTING l

Tests were conducted to meet the NRC criteria with concentration

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on the safety systems.

Initial tests indicated several ground ties were,.

present.

Supplemental tests were then conducted to isolate and correct the ground ties.

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2.2 ANALYSIS

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The inadvertent ties present were in one channel of the safety features actuation system (SFAS) and in the four channels of the reactor protection system (RPS) [Ref. 2).

Supplemental tests on each channel isolated the ground tie so as to determine whether the tie was in accordance with the design criteria or not.

An individual maintenance work order (MWO)

[Ref. 1] was then generated to correct each inadvertent ground tie which did not meet the design criteria.

3.

CONCLUSION Based on the information submitted by Toledo Edison Company for the Davis Besse Nuclear Power Station, Unit 1, it is concluded that:

(1)

An analysis and testing of the ground grid systems has been conducted per NRC criteria.

(2)

The ground ties found in the ground grid systems which do not meet design criteria have been isolated and corrected.

Accordingly, I recommend that the NRC accept the analysis and testing on the instrument and station ground grid systems to isolate and correct any inadvertent ties in the safety systems of the facility.

REFERENCES 1

NRC letter (D. B. Vassallo) to Toledo Edison Company (Lowell E. Roe),

dated September 26, 1977.

l 2.

Toledo Edison Ceepany (R. P. Crouse) to NRC (R. W. Reid), dated November 4, 1980.

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Based on the above, we find that the isolation noise testing performed on the RPS and SFAS is acceptable.

Conclusion

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Based on the information provided by the Toledo Edison Company for the Davis Besse Nuclear Power Station, Unit 1, the reactor protection system has adequately demonstrated its capability to perform the Class lE protective functions when subjected to electrostatic, electro-magnetic, isolation and noise level tests. The above tests were performed to NRC approved test methods and MIL-N-19900B as required and accordingly, we recommend approval of the isolation and noise testing of the reactor protection system to meet License Condition 2.c.(3)(k).

Also, based on the information submitted by Toledo Edison Company for the Davis Besse Nuclear Power Station, Unit 1, and the review of the test procedures, specifications, and test results, it is concluded that:

(1) No significant degradation to the Class lE circuitry occurred as a result of the fault tests.

(2) No spurious trips or resets of the relays occurred as a result of the fault tests.

(3) No spurious trips, resets, or reactions of the SFA system occurred as a result of the fault tests.

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TECHNICAL EVALUATION OF THE NOISE AND ISOLATION TESTING OF THE REACTOR PROTECTION SYSTEM FOR THE DAVIS BESSE NUCLEAR POWER STATION UNIT 1 t

(Docket No. 50-346)

James C. Selan Lawrence Livermore National Laboratory

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INTRODUCTION In a letter dated January 11, 1979 [Ref. 1], the Toledo Edison Company submitted test results from noise and isolation testing of the Davis Besse Nuclear Power Station's reactor protection. system (RPS).

The tests were required by Amendment No. 7 to the License Condition 2.c.(3)(k) which the NRC issued November 9,1977.

The purpose of the tests was to demonstrate that faults and interfert.tce noise on non-Class lE circuits would not propagate to Class IE s

circuits and degrade them below acceptable levels and to determine that selected system devices are immune to interference no'ise.

The testing was to be done in accordance with Section 4.6.11. " Susceptibility," of MIL-N-199008

[Ref. 2] and plant test methods previously submitted and approved by the NRC.

The purpose of this report is to evaluate the licensee's submittal,'

with respect to the NRC requirements.

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EVALUATION 9

t 2.1 TEST DESCRIPTION Thereactorprotectionsystem(880NI/RPS) was subjected to electromagnetic, electrostatic, and noise level tests.

Also, system isolation tests were performed on selected devices of the RPS.

A complete test description (test parameters, schematics, equipment list, procedures, and specifications) for each test was submitted by Toledo Edison Co.

[Ref. 1].

Each test consisted of four basic parts:

type of test, acceptance 1

criteria, pretest values, and post-test values.

Af ter the system or device was subjected to a selected type of test, the test values were analyzed to determine if the system or device failed to meet the acceptance criteria.

2.2 ANALYSIS This section presents a synopsis of the tests conducted and the results of the tests.

2.2.1 Isolation Capability Tests i

One bistable module and one fan failure de,t,ector were subjected to the isolation test to demonstrate the electrical isolation capability of the digite? isolation devices used in the reactor protection system.

6' The licensee states, and my analysis confirms, that both devices

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tested either met or exceeded the acceptance criteria with the exception of the j'.

insulation resistance test.

The resistance values obtained were influenced

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However, the absolute value of the insulation resistance readings were at least two orders of magnitude above I

the manufacturer's specifications, and this is determined to be acceptable.

2.2.2 Module Basis Electromagnetic Interference (EMI) Susceptibility Tests One contact-monitoring channel and one analog pressure channel were subjected to the EMI test to demonstrate the capability of the reactor protection system to perform Class 1E protective functions in the presence of electro-nagnetic and electrostatic interferences.

The licensee states, and my analysis confirms, that both devices tested cet all of the acceptance criteria.

o 2.2.3 Electrostatic Fault Tests The reactor protection system was subjected to electrostatic fault

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tests to demonstrate its capability to perform Class lE protective functions in the presence of transient signals.

These signals are capacitively coupled.

from fault voltages appearing on non-Class lE signal output leads.

The licensee states, and my analysis confirms, that the system j

tested met all of the acceptance criteria.

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2.2.4 Electromagnetic Fault Tests z"

l The reactor protection system was subjected to electromagnetic fault tests to demonstrate its capability to perforn Class 1E protective functions in the presence of electromag:. tic interference signals.

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nals are generated by fault currents flowing in non-Class lE signal output leads.-

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the licensee states, and my analysis confirms, that the system tested met all of the acceptance criteria.

2.2.5 Electromagnetic Interference (EMI) Susceptibility Tests The reactor protection system was tested to demonstrate the system's capability to perform its protective functions in the presence of electromagnetic

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and electrostatic interference signals that may appear on the non-Class 1E output signal cables outside the protection system cabinets.

A component failure during post-test recalibration should be noted.

One buffer amplifier could not be zeroed (exhibited a drift) in the checkout pcocedure. The component failure, as stated by the licensee, was random in nature and was not directly or indirectly induced by the testing procedure.

The licensee states that the component failure (dr.'ft) did not contribute an error of enough significance to invalidate the test results.

My analysis of the test rasults confirms the system tested met all of the acceptance criteria.

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CONCLUSION Based on the information provided by the Toledo Edison Company for the Davis Besse Nuclear Power Station,. Unit 1, the reactor protection system has adequately demonstrated its capability to perform the Class lE protective. functions when subjected *o electrostatic, electronagnetic, isolation and noise level tests.

The above tests were performed to NRC approved test methods and MIL-N-19900B as required.

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4 Accordingly, 1 recommend that the NRC approve the isolation and noise te. sting of the reactor protection system to meet License Condition 2.c.(3)(k).

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Toledo Edison Company letter and attachments to NRC (R. N. Reid),

dated January 11, 1979.

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Military Specification, Nuclear Propulsion Control and Instrumentation of Equipment, General Requirements (MIL-N-19900B), Section 4.6.11,

" Susceptibility."

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TECHNICAL EVALUATION OF THE

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NOISE AND ISOLATION TESTING OF THE SAFETY FEATURES ACTUATION SYSTEM AT THE DAVIS BESSE NUCLEAR POWER STATION UNIT 1 (Docket No. 50-346)

James C. Selan Lawrence Livermore National Laboratory 1.

INTRODUCTION y

By letters dated November 10, 1980 [Ref. 1], and March 4, 1981

[Ref. 2], the Toledo Edison Company submitted test results from noise and isolation testing of the Davis Besse Nuclear Power Station's safety features actuation system (SFAS).

The tests were required by Amendment No. 7 to the License Condition 2.c.(3)(k) which the NRC issued November 9,1977.

The purpose of the tests was to demonstrate that faults and inter-ference noise on non-Class lE circuits would not propagate to the Class lE circuits and degrade them below acceptable levels and to determine that selected system isolations devices will withstand _the interference noise.

The testing was done in accordance with plant test methods previously submitted and approved by the NRC.

The purpose of this report is to evaluate the licencee's submittal with respect to the NRC requirements.

2.

EVALUATION 2.1 Test Description The scope of the testing is to demonstrate that the isolation capability of the digital and analog isolation devices are not degraded to unacceptable levels following the inadvertent application of postulated 7Q qCO t

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electrical faults in excess of nor=al operating currents.- Also, that due to the intermix of non-Class 1E and Class lE signal wiring, postulated electrical

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faults appearing on the non-Class lE circuitry will not produce unacceptable effects in the Class lE circuitry by means of mutual inductance and/or capacitive coupling.

The isolation' device testing consisted of testing one of each type of device used in the SFAS Class lE to non-Class lE circuitry, while system

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testing consisted of utilizing one complete channel of the SFAS.

The licensee submitted complete test procedures, specifications, and test data for the tests conducted [Refs. 1 and 2].

2.2 Analysis This section presents a synopsis of the tests conducted and the results of the tests.

2.2.1 Digital Isolation Device Testing

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The three isolation devices subjected to the tests were the Clare Relay (KEL4318), the 6N81 bistable module, and the 6N83 output module. The results of the tests are as follows [Ref. 2]:

(1)

Clare Relay The licensee states that the application of either fault voltage or current to the relay contacts pro-duced no discernable effect on the Class lE (coil) side of the relay.

The input / output dielectric strength was not degraded below the system specifica-tion due to the fault application.

The relay was tested to failure which produced no effect on the Class lE circuitry or dielectric strength.

(2) 6N81 Bistable Module The licensee states that the application of the postulated faults t'o the output contacts of the 6h81 relay caused no inadvertent trips or resets of the bistable module.

(3) 6N83 Output Module The licensee states that the application of the postulated faults to the output (non-Class lE) contacts of the 6N83 relay caused no inadvertent r

trips or resets of the output module or relay.

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The device subjected to the tests was a KD978 Fischer Porter I/I, current to current isolator. The licensee states that the application of the postulated faults to the isolated (non-Class 1E) output produced no increase in noise on the. input 4-20ma loop when the loop is supplied by a

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constant current source.

2.2.3 SFAS Noise and Isolation Testing The containment pressure and reactor coolant systems modules were subjected to analog and digital electrical faults (current and voltage). The licensee states that the application of either fault voltage or current to the non-Class 1E output signal wiring caused no inadvertent trips, resets, or reactions of the system modules.

1 CONCLUSION Based on the information submitted by Toledo Edison Company for the Davis Besse Nuclear Power Station, Unit 1, and my review of the test procedures, specifications, and test results, it is concluded that:

(1) No significant degradation to the Class lE circuitry occurred as a result of the fault tests.

(2) No spurious trips or resets of the relays occurred as a result of the fault tests.

(3) No spurious trips, resets, or reactions of the SFAS system occurred as a result of the fault tests.

Accordingly, I recommend that the NRC approve the isolation and testing of the SFAS, which demonstrates that electrical faults on the non-Class 1E eircuits do not propagate to the Class lE circuits and degrade them i

l below acceptable levels nor affect the system's ability to perform its protec-l tive functions. This testing meets the requirements oftLicense Condition 2.c.(3)(k).

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e REFERENCES 1.

Toledo Edison Company letter (R.P. Crouse) to NRC (R. W. Reid), dated.

November 10, 1980.

2.

Toledo Edison Company letter and attachments (R.P. Crouse) to NRC (John F. Stolz), dated March 24, 1981.

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