ML20050C376

Sneak Circuit Analysis of ESF Loading Sequence Control Panel,June-Nov 1981.

ML20050C376
Person / Time
Site:	Summer
Issue date:	03/25/1982
From:	Gallaway J, Noss R, Jennivine Rankin BOEING SERVICES INTERNATIONAL, INC. (DIV. OF BOEING
To:
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ML20050C366	List: ML20050C365 ML20050C376
References
D2-118698-1, NUDOCS 8204080446
Download: ML20050C376 (55)

Text

l South Carolina Electric

& Gas Company I

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I FINAL REPORT

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j , . $[ Virgil C. Summer p c ) l- NUCLEAR STATION

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CKET NO. 50/395 N ,

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SNEAK CIRCUIT ANALYSIS of the

. Engineered Safety Features

, Loading Sequence Control Panel JUNE 1 - DECEMBER 1 1981 m

8204080446 B20325 PDR ADOCK 05000395 A PDR

THE COMPANY 4.

CODE IDENT. NO. 81205 NUMBER D2-118698-1 TITLE: SNEAK CIRCUIT ANALYSIS OF THE ENGINEERED SAFETY FEATURES LOADING SEQUENCE CONTROL PANEL FOR UMITATIONS IMPOSED ON THE USE OF THE INFORMATION CONTAINED IN THIS DOCUMENT AND ON THE DISTRIBUTION OF THIS DOCUMENT, SEE LIMITATIONS SHEET.

MODEL CONTRACT P.O. NLNBER 0283455 ISSUE NO. ISSUED TO:

PREPARED BY Ibww#

d. L. 6a6taway y SUPERVISED B ~ b $d APPROVED BY R. H. Nuss s

e SHEET u n .. omo../.s

D2-118696-1 .

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LIMITATIONS There are no limitations on the distribution of this docinent. However, all requests for this document to the Boeing Aerospace Company will first be cleared through South Carolina Electric & Gas Company. ,

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D2-118698-1 REVISIONS

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, D2-118698-1 ,

ABSTRACT i I

4 This report summarizes the methods and results of the Sneak Circuit Analysis of the Virgil C. Summer Nuclear Station, Engineered Safety Features Loading Sequencer cabinets. The analysis was performed under Purchase Order Number Q283455 for South Carolina Electric & Gas Company, Columbia, South Carolina.

The Sneak Circuit Analysis process produces network tree representations of electrical circuits for use in determining the presence of sneak condi-tions, design concerns, and drawing errors. The methods employed are described ir the text of this report. Final analysis of the network trees resulted in four Sneak Circuit Reports, eight Design Concern Reports, and nine Drawing Error Reports. The technical period of performance was from June 1, 1981 to December 1, 1981. Additional time was allowed for incorporation in this document of responses to each technical report issued during the effort.

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. 02-118698-1 TABLE OF CONTENTS SECTION PAGE e.

TITLE PAGE i LIMITATIONS ii REVISIONS 111 ABSTRACT iv TABLE OF CONTENTS V

1.0 INTRODUCTION

1 1.1 Background 1 2.0 SCOPE 2 3.0 TECHNICAL APPROACH 2 3.1 Input Data 3 3.2 Network Trees 3 3.3 Analysis 3 4.0 REPORT STATUS TRACKING 5 5.0 RESULTS 6

6.0 CONCLUSION

S 7 APPENDICES APPENDIX A DATA BASELINE A-1 APPENDIX B SNEAK CIRCUIT REPORTS B-1 o

APPENDIX C DESIGN CONCERN REPORTS C-1

. APPENDIX D DRAWING ERROR REPORTS D-1 APPENDIX E RESPONSES TO REPORTED ITEMS E-1 y

D2-118698-1

1.0 INTRODUCTION

This report documents the results of the Sneak Circuit Analysis performed on the Virgil C. Summer Nuclear Station, Engineered Safety Features Loading Sequencer cabinet electronics developed by Automation Industries, Inc.,

• Vitro Laboratories Division. This system was analyzed by the Boeing Aero-space Company under Purchase Order Number Q283455 for the South Carolina Electric & Gas Company. The purposes of this report are to: 1) define the scope of the analysis, 2) describe the general procedures used to de-tect sneak conditions, 3) document the accumulated results of the Sneak Analysis, and 4) show resolution of those items reported as part of the analysis.

1.1 Background The technique of a formal, systematic sneak analysis was initially developed in 1967 by the Boeing Aerospace Company in Houston, Texas, under contract to NASA. The analysis was first applied to electrical circuits and systems found on the Apollo manned spacecraft. Investigations and studies of unexpected operations and erroneous responses in aircraft and missile systems revealed cases that were believed to have been sneak circuit conditions. It was noted that few operational problems were 1

found during the design and test phases and that the sneak circuits were hidden in the circuitry or in the system operations. Sneaks conditions were found to be latent in nature and not dependent on the failure of components, although many erronous responses or failures may have initially been attributed to component failures. The sneak analysis technique was extended to identify sneak conditions in software in 1971.  ;

i 1

D2-118698-1 2.0 SCOPE The Sneak Circuit Analysis was performed on the electrical system of the

~

Virgil C. Summer Nuclear Station, Engineered Safety Features Loading Sequencer (ESFLS) to identify any potentially undesirable circuit conditions. This analysis was performed on'the ESFLS system as defined by the 'following- drawings:

Schematic Title Drawing Number Engineered Safety Features 2544-1013 Loading Sequencer Schematics Virgil C. Summer Nuclear Station Decoding Card No. 3-4 Electrical Schematic 0423-2674 Step Card No. 3-4 Electrical Schematic 0423-2679 Integrated Circuit Card No. 2 Electrical Schematic 0423-2589 Integrated Circuit Card No.1 Electrical Schematic 0423-2587 Integrated Circuit Card D Electrical Schematic 0423-2700 Component Card No. 2 Electrical Schematic 0423-2595 Clock Card Electrical Schematic 0423-2579 Lamp Driver Card Electrical Schematic 0423-2571 Time Delay-One Shot Module Electrical Schematic 0423-2637 1

l 1

3.0 TECHNICAL APPROACH

, The techniques of Sneak Circuit Analysis have been used to analyze various military, space, and commercial systems and are continuously updated to keep them current with today's technology These analysis techniques are discussed in the following sections.

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02-118698-1 3.1 Input Data The data required to perform a sneak analysis are detailed schematics, wire lists, system interconnect diagrams, selected component values, and commercial part numbers cf system components. Pertinent data useful to the analyses

. are such items as Design Specifications, Operational Descriptions, Main-tenance Procedures, and any information describing the system and its relationship to its operating environment. Upon receipt of the above material, a file is established and the data reviewed for applicability to the analysis and to identify any additional data that may be required for performance of the task. These data are then used as a baseline for the analysis. Data used in the analysis of the ESFLS were supplied to the Boeing Aerospace Company by South Carolina Electric & Gas Company, and a list of these data is included in Appendix A of this document.

3.2 Network Trees The data from the detailed schematics are converted to network trees.

This conversion is accomplished by converting the data base to a format for computer processing. To this formatted data, the automated sneak programs are applied to produce network trees. A network tree is a topological representation of a small part of the electrical / electronic system being analyzed. A network tree usually defines a completed circuit function and is drawn to show the electrical power source at the top and electrical returns at the bottom with signal flow from left to right for each figure.

3.3 Analysis A set of " Sneak Clues" is applied to each network ee to identify potential sneak conditions. Additionally, each component is checked to verify that its application is within its manufacturer's specifications.

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02-118698-1 -

3.3 Analysis (Continued)

A sneak clue is an item from a Boeing-developed checklist that defines the criteria in topological circuit representations or logic types for the identification of possible sneak conditions.

Sneak conditions are typically classified into the following four categories:

e Sneak Path - may cause data or e ergy to flow along an unexpected path, e Sneak Timing - may cause data or energy to flow at an unexpected time.

e Sneak Indications - may cause failure or ambiguous indications of system operating conditions.

e Sneak Labels - may cause incorrect stimuli or operating constraints to be initiated through operator error.

When a suspected sneak is identified, the analyst is required to verify that it is valid. The circuit is checked against the latest applicable drawings and specifications, and available operational information is reviewed. Following sneak verification, a Sneak Circuit Report is written which includes an explanation, system level impact, and a recommendation for the elimination of the sneak.

Items of concern including unnecessary circuitry, significant single failure points, improper implementation of redundancy, or improper application of canponents are reported as Design Concerns.

4

D2-118698-1 ,

In addition, discrepancies of information presented on two or more documents or discrepancies within a single document are reported as Drawing Errors.

e The Sneak Circuit Reports, Design Concern Reports, and Drawing Error Reports are normally delivered as attachments to the scheduled activity reports.

4.0 REPORT STATUS TRACKING Each -eport which was generated as a result of the Sneak Circuit Analysis was listed on the Report Status Sheets. These reports were forwarded to South Carolina Electric & Gas Company for subsequent distribution to the appropriate vendor or subsection for review and resolution. Following review of each report, a resolution was written and routed back to the Boeing Aerospace Company through South Carolina Electric & Gas Company.

The resolutton was reviewed for any additional concerns that may have been introduced and to verify that the response did, in fact, satisfy the particular reported concern. At that time the particular report was closed.

Each report was listed as "open" until such time as 'a response to a reported concern provided the rationale for closing the report. This rationale consisted of: 1) notification that the problem was corrected, without

, inclusion of change paper, 2) review of revised documentation showing how the problem was corrected, or 3) review of information provided for

' closing the report by acceptance of the condition without making a change to the design or documentation.

5

D2-118698-1 4.0 REPORT STATUS TRACKING (continued)

Upon receipt of the rationale for disposition, the type of corrective action to "close" each report was shown on the proper status sheet and was categorized as follows:

HDW - A change has been made to the hardware.

. DOC - A change has been made to the documentation.

ACC - A decision that the reported condition is acceptable as is.

The status sheets are included in Appendices B, C, and D along with the appropriate reports.

5.0 RESULTS The analysis of the ESFLS resulted in four Sneak Circuit Reports, eight Design Concern Reports, and nine Drawing Error Reports. Each of these reports have been resolved and are included in Appendices B, C, and D, respectively.

A sumary of these reports is shown as follows according to problem category and closecut action:

Report Number Problem Category Closecut Action SCR-1 Sneak Path Drawing Change SCR-2 Sneak Indication Drawing Change SCR-3 Sneak Indication Drawing Change SCh-4 Sneak Indication Document Change  ;

DCR-1 Unnecessary Circuitry No Change DCR-2 Improper Use of Logic No Change DCR-3 Unnecessary Circuitry No Change DCR-4 Improper Use of Logic No Change DCR-5 Single Failure Point Document Change ,

DCR-6 Single Failure Point No Change DCR-7 Reduced Noise Imunity No Changc DCR-S Component Damage No Change 6

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D2-118698-1

6.0 CONCLUSION

S The Engineered Safety Features Loading Sequencer has been found to be free of sneak circuits, subject only to the restrictions of data representations upon which the analysis was based and within the con-text of resolution of each technical report contained herein. All analysis findings were reported and resolved in a responsive manner, leaving no residual concerns. With appropriate resolution of each technical report as provided herein by South Carolina Electric &

Gas Company, the system is considered to be of the highest integrity of electrical / electronic design.

Each techi.ical report contained in Appendices B, C, and D provides its own detailed or technical conclusion in the CUSTOMER ACTION section.

All of these concerns are considered to be satifactorily resolved. The analytical effort has served as a reminder that flaws in equipment labeling and wiring may result from drafting errors unless the flaws are detected in documentation reviews. Any significant functional flaws that escape detection in the reviews will usually be uncovered by system testing before operations begin. However, it is possible that, in particularly complex circuitry, some alscrepancies may be undetected from testing and traditional design reviews until Sneak Circuit Analysis is performed. This is part y because complex circuitry cannot always i

, be tested in all possible modes at both the system functional le/el and the component level. Furthermore, design redundancy provisions and 7

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02-116698-1

6.0 CONCLUSION

S (Continued) reserve capacities often automatically compensate to mask detection of component deficiencies. Tested functions will then appear to be valid and the system will operate as planned. At worst, degradation of margins and reserves can result from such situations. By independently address-ing these issues, Sneak Circuit Analysis helps to assure that full capability and reliability are realized in such complex systems as the Load Sequencer.

The Design Concern Reports (Appendix C) issued during the Sneak Circuit Analysis typically dealt with methods of enhancing circuit reliability and improving documentation for subsequent uses. Also, system charac-teristics which could degrade component performance, areas of noise susceptibility,and single failure points were highlighted. These reports were resplyed as reported in the CUSTOMER ACTION resolutions.

The Drawing Error Reports (Appendix D) disclosed documentation discrepancies or ambiguities that could perhaps impede any subsequent troubleshooting of equipment problems. None of the reported discrepancies were of the type that could lead to improper manufacture of the hardware. The drawings have been corrected for future reference during South Carolina Electric &

. Gas Company's maintenance activities. Likewise, the manufacturer has been notified of all reported conditions for incorporation into future

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activities and design optimizations. The overall conclusion of the effort is to improve confidence in proper operation of the Engineered Safety Features Loading Sequencer as defined within the scope of the task.

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02-118698-1 i

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O APPEll01X A DATA BASELINE-W W

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D2-118698-1 I

Vitro Labs. No. SCE&G No. Title

. None IMS-94B-452-0 Instruction Manual for Emergency Safety Features Loading Sequence Control Panels, Virgil C. Summer

. Nuclear Station.

2544-1001 1MS-28-031-1-3 Engineered Safety Features Loading IMS-28-031-2-3 Sequencer Function Logic Diagram, IMS-28-031-3-4 Virgil C. Summer Nuclear Station.

1MS-28-031-4-4 2544-1013 1MS-28-096-1-2 Engineered Safety Features Loading IMS-28-096-2-2 Sequencer Electrical Schematics, IMS-28-096-3-3 Virgil C. Summer Nuclear Station IMS-28-096-4-2 1MS-28-096-5-2 1MS-28-096-6-5 1MS-28-096-7-2 1MS-28-096-8-5 1MS-28-096-9-2 1MS-28-096-10-4 1MS-28-096-11-4 1MS-28-096-12-3 1MS-28-096-13-3 1MS-28-096-14-4 1MS-28-096-15-5 1MS-28-096-16-1 1MS-28-096-17-1 IMS-28-096-18-1 1MS-28-096-19-1 1MS-28-096-20-3 1MS-28-096-21-2 1MS-28-096-22-1 1MS-28-096-23-1 1MS-28-096-24-1 2544-1019 1MS-28-258-0 Integrated Circuit Card No. 2B Assembly PL2544-1019 1MS-28-233-1-1 Integrated Circuit Card No. 28 Assembly IMS-28-233-2-1 0423-2699 1MS-28-290-0 Component Card B Assembly

. 0423-2693 1MS-28-291-1-A Integrated Circuit Card A Assembly 0423-2697 1MS-28-205-0 Integrated Circuit Card D Assembly

-0423-2696 1MS-28-287-0 . Integrated Circuit Card C Assembly A-2

D2-118698-1 Vitro Labs. No. SCE&G No. Title 0423-2670 1MS-28-285-0 Decoding Card No. 3 Asstably

. 0423-2674 IMS-28-254-0 Decoding Card No. 3-4 Electrical Schematic

, 0423-2675 1MS-28-295-0 Step Card No. 3 Assembly 0423-2679 1MS-28-261-0 Step Card No. 3-4 Electrical Schematic Diagram 0423-2571 1MS-28-279-0 Lamp Driver Card Electrical Schematic 0423-2570 1MS-28-278-0 Lamp Driver Card Assembly PLO423-2570 1MS-28-234-1-1 Lamp Driver Card IMS-28-234-2-1

0423-2578 IMS-28-260-0 Clock Card Assembly 0423-2579 1MS-28-277-0 Clock Card Electrical Schematic 0423-2636 1MS-28-274-0 Time Delay One Shot Module Card Assembly PLO423-2636 1MS-28-235-1-1 Time Delay One Shot Module Card IMS-28-235-2-1 Assembly 0423-2637 1MS-28-296-0 Time Delay One Shot Module Electrical Schematic Diagram 0423-2640 1MS-28-275-0 Seven Segment Dispicy Driver Card Assembly PLO423-2640 1MS-28-236-1-1 Seven Segment Display briver IMS-28-236-2-1 Card Assembly IMS-28-236-3-1 0423-2641 IMS-28-307-0 Seven Segment Display Drive"

. Module Electrical Schematic 0423-2657 1MS-28-256-0 Integrated Circuit 0423-2587 1MS-28-263-0 Integrated Circuit Card No.1 Electrical Schematic 0423-2589 1MS-28-262-0 Integrated Circuit Card No. 2 Electrical Schematic 0423-2700 1MS-28-265-0 Integrated Circuit Card D Electrical Schematic Diagram A-3

D2-118698-1 -

I Vitro Labs. No. SCE&G No. Title 0423-2595 1MS-28-276-0 Component Card No. 2 Electrical Schematic Standard Drawing 2544-1002 1MS-28-071-1-5 External Wiring Diagram ESF Loading IMS-28-071-2-5 Sequencer 1MS-28-071-3-5 0423-2644 1MS-28-268-0 Guide Switch Plunger 0423-2648 1MS-28-269-0 Bracket, Switch Mounting 2544-1018 1MS-28-257-0 Support, Pltg 2544-1016 1MS-28-266-0 Angle, End 0423-2708 IMS-28-264-0 Strap, Cable 0423-2651 IMS-28-270-0 Bar, Ground 0423-2512 1MS-28-267-0 Plate, Identification, Rigid 0423-2551 IMS-28-259-0 Rack (Two rows) 0423-2555 1MS-28-273-0 Plate, Identification Vitro Emblem 2544-1021 1MS-28-280-0 Stiffener 0423-2632 1MS-28-281-0 Strip, Marking Card File 0423-2644 1MS-28-271-0 Bracket, Cover 0423-2645 1MS-28-272-0 Digital Isolater Assembly N

'I A-4

D2-118698-1 ,

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APPENDIX B SNEAK CIRCUIT REPORTS O

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8 SNEAK CIRCUIT REPORT STATUS CORRECTIVE NO. R TITLE DATE STATUS ACTION REMARKS HDW DOC ACC 1 APPLICATION OF 115VAC T0.+15VDC DIGITAL LOGIC CIRCUITRY 9/16/81 CLOSED X 2 POSSIBLE FALSE INDICATION OF DIESEL GENERATOR BREAKER STATUS 11/4/81 CLOSED X, 3 POSSIBLE LOSS OF FAULT INDICATION DURING AUTO TEST 7 11/4/81 CLOSED X 4 POSSIBLE CONTINUOUS FAULT INDICATION SIGNAL 11/10/81 CLOSED X

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D2-118698-1 PROJECT SCE&G LOAD SEQUENCER PAGE 1 OF 2 SNEAK CIRCUlT REPORT - 1 TITLE APPLICATION OF 115 VAC TO +15 VDC DIGITAL LOGIC CIRCUITRY

. REFERENCES

1. Automation Industries, Inc., Vitro Laboratories Division, Drawing No. 2544-1013,

" Engineered Safety Features - Loading Sequencer Electrical Schematics - Virgil C. Summer Nuclear Station," sheet 5 (rev. 2), sheet'8 (rev. 5), and sheet 9 (rev. 2).

2. Automation Industries, Inc., Vitro Laboratories Division, Drawing No. 0423-2679,

" Step Card No. 3-4 Electrical Schematic Diagram ," Rev. O.

MODULE / EQUIPMENT EXPLANATION As shown in Figure 1 and the referenced drawings, 115 VAC power is applied to XA3 pin 21 (."STEF 1") when contacts 6 & 9 of relay XK21 and contacts 1 & 2 of relay K16 are closed. As a result,115 VAC is provided to +15 VDC logic within the XA3 card at pin 12 (an input) of device U17 and at pin 8 (an output) of device U15. Application of 115 VAC to these devices will cause them to fail and will result in the loss of the " STEP 1" signal.

POTENTIAL IMPACT Component damage and loss of " STEP 1" signal caused by application of 115 VAC to +15 VDC digital logic .ircuitry.

RECOMMENDATION Disconnect XA3 pin 21 from contact ? of K16. Next, determine the appropriate external connection for XA3 pin 21 and provide the necessary wiring.

REPORTED BY S. S. Burch }tdm l.bd DATE 9/16/81 CUSTOMER ACTION Vitro considers this to be a . drawing error and recomends Node 33 on sheet 5 and sheet 12 of f!eference 1 be changed to Node 125.

Boeing agrees.

B B E/ M G ^&?fe2'&M** B-3

D2-118698-1 PROJECT SCE&G LOAD SEQUENCER PAGE 2 OF 2 SNEAK CIRCUIT REPORT - 1 1

. 1 j 115 VAC NOTES:

f --S DEN 0TES CONNECTION TO XK21 OTHER CIRCUITRY 9

' DEN 0TES SNEAK CURRENT PATH 1

K16 2

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l FIGURE 1. APPLICATION OF 115 VAC TO DIGITAL LOGIC CIRCUITRY

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E D2-118698-1 PROJECT SCE&G LOAD SEQUENCER PAGE 1 OF 3 SNEAK CIRCulT REPORT - 2 TITLE POSSIBLE FALSE INDICATION OF DIESEL GENERATOR BREAKER STATUS

. REFERENCES

1. Specification SP-569-044461-000, ESF Loading Sequencer Control Panels-Virgil C. Summer Nuclear Station , January 14, 1976, 2:08.8.3 pg. 33.

2. Automation Industries, Inc. , Vitro Labs. Div., Dwg. No. 2544-1013,

" Engineered Safety Features Loading Sequencer Electrical Schematics, Virgil C. Summer Nuclear Station ," sheet 2, rev. 2.

MODULE / EQUIPMENT EXPLANATION As indicated by Reference 1, a contact closure indicates to the Loading Sequencer that the" Diesel Generator Breaker"is closed. However, as indicated by Figure 1, an excerpt from Reference 2, when the contact indicating the status of the Diesel Generator Breaker is open, relay KX27 is deenergized. In this state a " LOGIC ONE" is applied to the set input and a " LOGIC 0" to the reset input of the NAND latch making up the " Diesel Generator Breaker Closed" Input to the ESF Loading Sequencer. With this input the " Diesel Generator Breaker Closed" Lamp, A3DS7, will be illuminated 3

and the " Diesel Generator Breaker Open" Lamp, A3DS8, will be off. When the contact indicating the status of the Diesel Generator Breaker is closed, the

" Diesel Generator Breaker Closed" Lamp will be off and the Diesel Generator Breaker Open" Lamp will be illuminated.

POTENTIAL IMPACT Possible false local indication of Diesel Generator Breaker status.

RECOMMENDATION Change the label on Lamp A3DS7 from "DG BKR CLOSED" to "DG BKR OPEN" and the label on Lamp A3DS8 from "DG BKR OPEN" T0 "DG BKR CLOSED" (See Figure 2).

. REPORTED BY J. L. Gallaway . Obb DATE 11/4/81 CUSTOMER ACTION Vitro considers this to be a drawing error and recommends correcting the wire connections on Reference 2.

Boeing agrees.that the proper wire connnection designations will eliminate the problem if the device is properly wired.

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115VAC COM TRUTH TABLE d CONTACT CLOSURE INDICATING DIESEL GENERATOR STATUS 1 0 DS8 0FF DS7 ON d ONLY ONE INPUT IS IN USE 0 1 ON OFF d ONLY THOSE CONNECTIONS TO BUBBLES 5, 11, 12, & 214 RELATING TO THIS PROBLEM ARE SHOWN I

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02-118698-1 PROJECT SCE&G LOAD SEQUENCER PAGE 1 OF 2 SNEAK CIRCulT REPORT - 3 TITLE POSSIBLE LOSS OF FAULT INDICATION DURING AUTO TEST 7

- REFERENCES Automation Industries, Inc., Vitro Labs. Div.,Dwg. No. 2544-1013,

" Engineered Safety Features Loading Sequencer Electrical Schematics,

. Virgil C. Summer Nuclear Station ," sheet 20, rev. 3.

MODULE / EQUIPMENT 1MS-28-096 EXPLANATION Within the subject drawing, no match can be found for bubble 260, "AT MEM RESET"; the only connection to this bubble is the reset of device U3B XA14 (MC663 JK-FF); see Figure 1. From the signal name at this bubble and from the U3B clock signal name, it is assumed that device U38 is part of the automatic test of STEP circuits.

However, since the reset line is unconnected, device U3B cannot function in conjunction with the periodic operation of the automatic test circuits.

POTENTIAL IMPACT The unconnected reset line of device U3B may inhibit test function.

RECOMMENDATION Connect the open reset line of device U3B to the appropriate circuitry.

. REPORTED BY P. Scarlato , q ,

DATE 11/4/81 CUSTOMER ACTION Vitro recommends that the referenced schematic be changed to show a connection from bubble 160 to XA11-58.

Boeing agrees that this will correct the situation.

B O N N G $${okh%5s* B-8

2 2 PROJECT SCE&G LOAD SEQUENCER PAGE OF SNEAK CIRCUIT REPORT - 3

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D2-118698-1 1 1

PROJECT SCE8G LOAD SEQUENCER PAGE 1 OF 2 SNEAK CIRCulT REPORT - 4 l

TITLE POSSIBLE CONTINUOUS FAULT INDICATION SIGNAL l

. REFERENCES

1. Automation Industries, Inc., Vitro Labs Div., " Instruction Manual for Engineered Safety Features Loading Sequence Control Panels, Virgil C.

. Summer Nuclear Station ," June 1977.

2. Automation Industries, Inc. , Vitro Labs. Div. , Dwg. No. 2544-1013,

" Engineered Safety Features Loading Sequencer Electrical Schematics, Virgil C. Summer Nuclear Station."

MODULE / EQUIPMENT EXPLANATION Reference 1 lists relay K80 as a KUP14A15 relay with a 120VAC coil. However, on sheet 21, zone B-4 of Reference 2, relay K80 is shown energized by 24VDC (see Figure 1).

POTENTIAL IMPACT Relay K80 will not pick up and a fault indication will be given at all times.

RECOMMENDATION Replace the 120VAC coil in relay K80 with a 24V coil.

REPORTED BY J. L. Gallaway 11/10/81 DATE CUSTOMER ACTION Vitro recommends that Reference 1 be changed such that K80 is listed as the same type as K67.

Boeing agrees.

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D2-118698-1 APPENDIX C DESIGN CONCERN REPORTS l

l C-1

I DESIGN CONCERN REPORT STATUS CORRECTIVE NO. R TITLE DATE STATUS g,,]C" Acc RMME 1 1 UNNECESSARY CONNECTIONS TO PULL-UP RESISTORS 10/8/81 CLOSED X 2 POSSIBLE IMPROPER OPERATION OF MC669 4-INPUT EXPANDER CIRCUIT CARDS 11/3/81 CLOSED X 3 NONESSENTIAL DIODES 11/5/81 CLOSED X e

4 INITIATION OF SLOW TEST MAY CAUSE ADVANCE IN TEST COUNTER 11/9/81 CLOSED X 5 POSSIBLE INHIBITED INDICATION OF LOSS OF +24VDC P,0WER SUPPLY 11/30/82 CLOSED X As a result of SCR 4 6 SINGLE POINT FAILURES WITHIN LOAD SEQUENCER ELECTRONICS 11/30/81 CLOSED X 7 REDUCED SYSTEM NOISE IMMUNITY 11/30/81 CLOSED X y 8 INADVERTENT COUNTER DESTRUCTION DUE TO HUMAN ERROR 11/30/81 CLOSED

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l D2-118698-1 PROJECT SCE&G LOAD SEQUENCER PAGE 1 OF 4

! DESIGN CONCERN REPORT- 1R1 TITLE UNNECESSARY CONNECTIONS TO PULL-UP RESISTORS l REFERENCES

1. Automation Industries, Inc., Vitro Labs. Div., Dwg. No. 0423-2674, Rev. Basic, " Decoding Card No. 3-4 Electrical Schematic Diagram." l

2. Automation Industries, Inc., Vitro Labs. Div., Dwg. No. 0423-2670, a Rev. B. , " Decoding Card No. 3 Assembly."

3. Electronic Engineers Master Catalog,Vol. 2 1980-81, 23rd Edition, Page 3765.

MODULE / EQUIPMENT EXPLANATION In zones D-4 and C-4 of Reference 1, U18 and U19 are shown connected to U2 and U8 as shown in Figure 1. Also, Note 1 of Reference 1 states that Vcc is connected to pin 16 of U18 and U19. However, as indicated by References 2 and 3, U18 and U19 are Allen-Bradley 314A682 resistor networks 14 pin packages. It should also be noted that, on Reference 1, U18 implies a connection of U2, pin 9. If so, this would require U18 and U19 to be 16 pin packages. However, since U18 and U19 are 14 pin packages, the connections to U2 and V8 from pins 8, 6 & 7 to pins 10, 6 & 7, respectively, are unnecessary. The devices driving the inputs of U2 and U8 have more than sufficient drive capability and these connections only increase power dissipation and reduce reliability.

POTENTIAL IMPACT Unnecessary connections to pull-up resistors may result in reduced reliability, increased power consumption, and added maintenance time.

RECOMMENDATION Remove the connections between U18 (U19) pins 8, 6 & 7 and U2 (U8) pins 10, 6 & 7, respectively (see Figure 2). Remove U18 (U19) from the list of devices having Vcc applied to pin 16 and place U18 (019) 'n tne list of devices receiving power through pin 14 (see Figure 3).

REPORTED BY J. Gallaway _o ,I[m;-V DATE 10/8/81 CUSTOMER ACTION Vitro does not recommend a change.

Boeing agrees due to relative insignificance of the problem.

I 1

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C-3

D2-118698-1 PROJECT SCE&G LOAD SEQUENCER PAGE_2._ OF 4 l DESIGN CONCERN REPORT - 1R1 NOTE 1

. - - - - - - 1 1_4 _ _ _ _ _ _ _ _ _ _ _ _, _ _ l l U18 (U19)  ;

ALLEN-BRADLEY 314A682 I

NOTE 2 l I

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8 6 7 5

54- 3~ 2 1 13 12 T1 10~3- l

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U2 3

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MC676P 15 h

, 10 ,

14

, 9 13 '

1. a 12 ,

11 NOTES:

1. NOTE 1 0F REFERENCE 1 DOES NOT INDICATE A CONNECTION

2. ALL RESISTORS ARE 6.8K +2%. -

FIGURE 1 EXISTING CIRCUITRY B U S/N U Ri{$h5Y* C-4

D2-118698-1 PROJECT SCE&G LOAD SEQUENCER PAGE 3 op 4 DESIGN CONCERN REPORT - 1R1 NOTE 1

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I L4 7------ - - - - - _ _ _ _ _ _ _ _ _

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l U18 (U19)'  ;

ALLEN-BRADLEY 314A682 I l NOTE 2 l 1 g j l  !

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,,8 ,,6 7 5 5 4 3 2_ 1 13 12 11 109 _

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U2 3 6

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I MC676P

, 10 15 ,

14 9

, 9 13 ',

3 12 ,'

11 '

NOTES:

1. NOTE 10F REFERENCE 1 DOES NOT INDICATE A CONNECTION

2. ALL RESISTORS ARE 6.8K +2%. -

. FIGURE 2 RECOMMENDED CHANGE' 1

B U f / N G CEui{$lhLT

• C-5

02-118698-1 PROJECT SCE&G LOAD SE0VENCER PAGE 4 OF 4 DESIGN CONCERf! REPORT - 1R1

. NOTES:

1.' UNLESS OTHERWISE SPECIFIED VOLTAGE (VCC)

AND GND ARE CONijECTED TO MICRot0Lic DEVICE PINS AS FOLLOWS:

VCC PlN 14-U15, U16, U17 .-%--.--

PIN 16-U1, U2, U7, U8, U13, U14!' U18, U19 'r

' GND PIN;7 -U15, U16?iU17'

. PIN 8 - Ul, U2, 07,, U8,, U.13f U14 , . .. _,.

FIGilRE 3 EXCEP.PT FROM REFEREllCE 1, RECOMMENDED CORRECTION TO NOTE 1 S O N S N U A'S$ $ ?tuY

• C-6

D2-118698-1 PROJECT SCE&G LOAD SEQUENCER PAGE 1 OF 2 DESIGN CONCERN REPORT -2 TITLE POSSIBLE IMPROPER OPERATION OF MC669 4-INPUT EXPANDER CIRCUIT CARDS REFERENCES

1. Automation Industries, Inc., Vitro Labs. Div. Dwg.,No. 2544-1013,

, " Engineered Safety Features Loading Sequencer Electrical Schematics, Virgil C. Summer Nuclear Station ," sheet 23 & 24, rev.1.

2. Teleconference with Gene Heaveycan, Motorola Semiconductor Div.,

Phoenix, Arizona.

MODULE / EQUIPMENT 1MS-28-096 EXPLANATION Circuit cards XA17 and XA18, Part No. 0423-2693-7, do not show a circuit ground pin connection (see Reference 1); these ground circuits are therefore assumed to be floating. However, according to Reference 2, these circuit pins "...must be grounded" for proper operation of these devices.

POTENTIAL IMPACT Improper operation of 4-Input Expanders within the system.

RECOMMENDATION Connect pin 1 of circuit cards XA17 and XA18 to D.C. systems ground.

. REPORTED BY J. L. Gallaway

, M,MwT DATE 11/3/81 ,

CUSTOMER ACTION ,

. Vitro does not recommend a change.

Boeing agrees, under the assumption that Vitro has verified this with the manufacturer.and that the device has been properly tested for satisfactory operation.

B O M N G ?$?{$N'h*$

• c_7

l 02-118698-1 PROJECT SCE&G LOAD SEQUENCER PAGE OF DESIGN CONCERN REPORT- 3 i TITLE NONESSENTIAL DIODES REFERENCES Automation Industries, Inc. , Vitro Labs. Div. , Dwg. No. 2544-1013.

" Engineered Safety Features Loading Sequencer Electrical Schematics, Virgil C. Summer Nuclear Station ," sheet 18, rev.1.

MODULE / EQUIPMENT 1MS-28-096 EXPLANATION In zone SC of the subject drawing, diodes CR12 & 28 provide no useful purpose in the circuit (see Figure 1).

POTENTl/ L IMPACT Nonessential components may degrade the system's reliability.

RECOMMENDATION Remove the nonessential components from the circuit of the subject drawing; remove the connection between the outputs of devices U3B and U3C.

%4

. REPORTED BY P. Scarlato p .

DATE 11/5/81 CUSTOMER ACTION

. Vitro does not feel the removal of the diodes will add significantly to system reliability.

Boeing agrees; the influence is negligible in terms of expected re-liability ratings.

B O M N O ?<?d?{$ h*E

• C-8

D2-118698-1 PROJECT SCE&G LOAD SEQUENCER PAGE 2 OF 2 DESIGN CONCERN REPORT - 3 l

Ns i u36 - C uGs' + l1 ' * '

+ ' O'P Eg Call t NONESSENTIAL XA11

1. 1. 2# 9 COMP 0NENTS g

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xarA AM CR - XAlf FIGURE 1 70NE SC 0F THE SUBJECT. DRAWING EME/NM0ggy ht[^* C-9

02-118698-1 PROJECT SCE&G 1.0AD SEQUENCER PAGE 1 OF 2 DESIGN CONCERN REPORT -4 i

TITLE INITIATION OF SLOW TEST MAY CAUSE ADVANCE IN TEST COUNTER REFERENCES Automation Industries, Inc., Vitro Labs.Div., Dwg. No. 2544-1013,

" Engineered Safety Features Loading Sequences Electrical Schematics, Virgil C. Summer Nuclear Station ," sheet 16, rev.1, zone 6A.

MODULE / EQUIPMENT 1MS-28-096 EXPLANATION At the initiation of a " Slow" test, an oscillation may be introduced into the clock line of the test counters; this would cause the test counters to advance in counts without the use of the " MANUAL" button circuit. When a " Slow" signal is in transition, there may be enough noise through capacitor CUS-7 (see Figure 1) to cause spurious clock pulses at the output of device U1A.

POTENTIAL IMPACT During the initiation of a " Slow" test, the test counter may advance past count 00 before the " MANUAL" button is pushed due to spurious clock pulses.

RECOMMENDATION To correct the possiole introductior of spurious clock pulses, capacitor CU8-7 should be removed and the circuit should be converted into a Schmitt Trigger as shown in Figure 2.

REPORTED BY P. Scarlato ,

(f), (t ,

DATE 11/P.'81 CUSTOMER ACTION

- Vitro does not recommend a change.

Boeing agrees on the basis of the improbability of the combination of the spurious clock pulses in association with the slow rise time of the clock signals resulting in the advance of the test counter. Al so, it is recognized that this situation would only occur during mdintenance activities.

SUNNSc?bliSY5" C-10

l l l D2-118698-1 PROJECT SCE&G ' LOAD SEQUENCER 2 2 :

PAGE OF DESIGN CONCERN REPORT - 4 i

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FIGURE 2 RECOMMENDED CHANGE M ME/XM Ms!fixT,* C-11

l D2-118698-1 l PROJECT SCE&G LOAD SE0VENCER PAGE 1 OF __2_

l l DESIGN CONCERN REPORT - 5R1 TITLE POSSIBLE INHIBITED INDICATION OF LOSS OF 424VDC POWER SUPPLY REFERENCES Automation Industries, Inc., Vitro Labs. Div., Dwg. No. 2544-1013,

" Engineered Safety Features Loading Sequencer Electrical Schematics,

. " Virgil C. Summer Nuclear Station."

MODULE / EQUIPMENT EXPLANATION Should the +24VDC power supply fail open,an indication of this fault may be inhibited by current feeding from the +15VDC power supply to the +24VDC system, thus holding relay K80 in. This is based on the assumption that relay K80 has a 24 volt coil (see SCR-4). An example of the 18 paths that exist to supply current to this relay is shown in Figure 1. The current paths are those connections to bubbles 61, 64, 65, 67-71, and 73-82 (see Figure 1).

POTENTIAL IMPACT If the +24VDC power supply fails, the lead sequencer would fail to respond properly to input signals.

RECOMMENDATION Redesign as necessary such that a " Fault" output would result upon loss of the +24VDC power supply.

. REPORTED BY J. L. Gallaway .

htuc[ DATE 11/30/81 CUSTOMER ACTION

. Vitro does not recommend any circuit modification.

Boeing agrees, on the basis of the improbability of relay K32 and relay K80 remaining energized due to the change in SCR-4.

l

" N C-12

, 02-118698-1 2

PROJECT SCE&G LOAD SEQUENCER PAGE OF DESIGN CONCERN REPORT - 5 R1 j i

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+24VDC +15VDC

+24VDC

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NOTES:

@ BUBBLES AS LISTED IN BODY OF REPORT

@ FEEDBACK PATH EXISTS ONLY WHEN OUTPUT IS OFF

@ " STEP" AND "0UTPUT" RELAYS

/ DIRECTION OF CURRENT FLOW FIGURE 1: EXAMPLE FEEDBACK PATH l

l l

l X ME/N M0@/s!&uT* C-13 l

l D2-118698-1 PROJECT SCE&G LOAD SEQUENCER PAGE 1 OF 2 DESIGN CONCERN REPORT - 6 TITLE SINGLE POINT FAILURES WITHIN LOAD SEQUENCER ELECTRONICS REFERENCES Automation Industries, Inc., Vitro Labs, Div., Dwg. No. 2544-1013,

" Engineered Safety Features Loading Saquencer Electrical Schematics, Virgil C. Summer Nuclear Station."

MODULE / EQUIPMENT EXPLANATION This area of concern is the design philosophy of the interface between the electronics portion of the Load Sequencer and the relay portion.

The relay portion seems to be designed for " fail without output", while the electronics have a number of single point failures that may result in the inhibiting or initiating of an output. These single point failures may or may not be detected in the normal automated test mode of operation. An example of some of the possible failures that may result are shown in Figure 1.

POTENTIAL IMPACT Possible reduced reliability or degradation of available margins and reserves as well as possible increased maintenance requirements.

RECOMMENDATION Investigate component level single point failures and determine their impact on system level reliability and maintenance levels.

REPORTED BY -

DATE CUSTOMER ACTION Gilbert Associates, Inc.'s verbal response indicates that, should the Load

. Sequencer fail so as to initiate an undesired action, the operators will then correct the situation. Also, if the Load Sequencer fails to operate at all, a redundant Load Sequencer will be used to perform the required functions.

Boeing concurs that the issue may be resolved in this manner. However, to rely upon operator actions to protect plant equipment leaves susceptibility to human error.

BOMNG@{&*y" C-14

D2-118698-1 PROJECT SCE&G LOAD SEQUENCER PAGE 2 OF 2 DESIGN CONCERN REPORT - 6 l

115VAC

+24VDC TO TEST CIRCUITS S O % ,, 5 0 4 _

ZI 52 l

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DC RTN 1 TN DC RTN

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/ \, FAILURE OPEN RESULTS IN RELAY ENERGIZED N,'

/~'s FAILURE SHORT RESULTS IN RELAY ENERGIZED i ' -- '

8 l- ~ ~ ~l FAILURE OPEN RESULTS IN OUTPUT BEING INHIBITED.

i j NOT DETECTABLE DURING NORMAL TEST MODE i

L _ _ _ii NOTE:

@ CONTACTS OF RELAY INTERFACE WITH EXTERNAL CIRCUITRY FIGURE 1 TYPICAL LOAD SEQUENCER OUTPUT BGMNGayyy hut

• C-1s

D2-118698-1 PROJECT SCE&G LOAD SEQUENCER PAGE 1 OF 1 DESIGN CONCERN REPORT - 7 l

TITLE REDUCED SYSTEM NOISE IMMUNITY REFERENCES Automation Industries, Inc., Vitro Labs. Div., Dwg. No. 2544-1013

" Engineered Safety Features Loading Sequencer Electrical Schematics, Virgil C. Sumer Nuclear Station."

MODULE / EQUIPMENT EXPLANATION A normal design practice is to filter the power supply at each circuit card. However, the following circuit cards are not shown to have this filtering: XA7, 8, 10-13, 14-16, 20, 21, 24, 34, 35, 39, 40, 42, 43, and 45 47. Those circuit cards not listed have filter capacitors or are considered not to require them.

POTENTIAL IMPACT Increased system switching noise and decreased system noise immunity, RECOMMENDATION Consider adding a 1.2pf and a 0.1pf capacitor in parallel to the above mentioned circuit cards.

REPORTED BY J. L. Gallaway -

DATE 11/30/81 CUSTOMER ACTION Vitro does not recommend a change.

Boeing agrees. that any anticipated improvement would be minor unless field test data indicates that noise problems exist in the system or unless " noise generators" are added in the area by future installation modifications.

88MXMfcl81%C'E4^* C-16

l D2-118698-1 PROJECT SCE&G LOAD SEQUENCER PAGE 1 OF 1 DESIGN CONCERN REPORT - 8 TITLE INADVERTENT COUNTER DESTRUCTION DUE TO HUMAN ERROR l

REFERENCES Automation Industries, Inc., Vitro Labs. Div. , Dwg. No. 1544-1013,

" Engineered Safety Features Loading Sequencer Electrical Schematics, Virgil C. Summer Nuclear Station."

MODULE / EQUIPMENT EXPLANATION Switches on the Time Delay /One Shot card and the Step and Decoder cards presently allow more than one counter output to be connected together. l This may result in inadvertent damage to the Time Delay /0ne Shot counter outputs or an invalid output, as in the case of the Step and Decoder cards.

POTENTIAL IMPACT Should this occur, an invalid output may result or destruction of the counter may occur.

RECOMMENDATION Consider replacing the DIP switch paks with a switch pack on which one switch only may be closed at any one time.

REPORTED BY J. L. Gallaway 1 fli/I'""[ DATE 11/30/81

, l CUSTOMER ACTION Vitro does not recommend a change.

Boeing agrees on the basis that there are procedures to cover this situation. However, this does not preclude the introduction of human error.

88MNM$'l$y h8" c C-17

w- - -

. 02-118698-1 APPENDIX D DRAWING ERROR REPORTS I

e e

0-1

i DRAWING ERROR REPORT STATUS CORRECTIVE ACTION NO. R DWG. NO. REV. VENDOR DATE STATUS REMARKS HDW DOC ACC 1 2544-1013 3/5 VITRO LABS. 8/26/81 CLOSED X 1MS-28-096-13,15 Shts - 13 & 15 2 2544-1013 3 VITRO LABS. 8/26/81 CLOSED X IM3-28-096-12 Sht. 12

< 3 0423-2637 A VITRO LABS. 8/26/81 CLOSED X IMS-28-296-0 4 0423-2579 A VITRO LABS. 8/26/81 CLOSED X 1MS-28-277-0 5 2544-1013 VITRO LABS. 11/5/81 CLOSED X 1MS-28-254 6 2544-1013 VITRO LABS. 11/5/81 CLOSED X IMS-28-254 i

7 SP-569-044461-000 JAN/7f SCE&G 11/6/81 CLOSED X 8 ,

8 0423-2674 0 VITRO LABS. 11/5/81 CLOSED X IMS-28-254 3 9 IMS-94B-452 JUN/7: VITRO LABS. 11/6/81 CLOSED X y*

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4

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D2-118698-1 PROJECT SCE&G LOAD SEQUENCER PAGE 1 OF 1 DRAWING ERROR REPORT _1

. < ' DOCUMENT NUMBER REV VENDOR MODULE / EQUIPMENT 2544-1013' 3/5 VITRO LABS. 1MS-28-096-13,15 DOCUMEN T . TITLE ENGINEERED SAFETY FEATURES LOADING SEQUENCER ELECTRICAL SCHEMATICS ,

\

REFERENCES l DISCREPANCY l In zone.3B of sheet 13 and 3D of sheet 15, bubble 72 is labeled as "115 VAC." However, sheets 11, 12, 14 of the same drawing show bubble 72 labeled as "115 VAC COM."

ASSUMED CORRECTION Change the label on bubble 72 to "115 VAC COM" on sheets 13 and 15.

f

' ** O M""- 8/26/81

. REPORTED BY DATE CUSTOMER ACTION 1

- Nitro agrees with the recommended correction.

i i

MM((MM N u D-3

~

D2-118698-1 PROJECT SCE&G LOAD SEOUENCER PAGE 1 OF 1 DRAWING ERROR REPORT -2 DOCUMENT NUMBER REV VENDOR MODULE / EQUIPMENT 2544-1013 3 VITR0 LABS. 1MS-28-096-12 DOCUMENT TITLE

~

ENGINEERED SAFETY FEATURES LOADING SEQUENCER ELECTRICAL SCHEMATICS REFERENCES DISCREPANCY The subject drawing indicates that the function of the connection to node 24 on sheet 12 is " STEP 1." However, sheets 5 and 11 of the same drawing show the connection labeled as " STEP 1."

ASSUMED CORRECTION Add an inversion bar to " STEP 1" on sheet 12 of the subject drawing.

• REPORTED BY C. Lee CC h b DATE 8/26/81 CUSTOMER ACTION Correct as stands. Due to changes made by SCR-1.

i I

D2-118698-1 PROJECT SCE&G LOAD SE0VENCER PAGE 1 OF 1 DRAWING ERROR REPORT - 3 l

DOCUMENT NUMBER REV VENDOR MODULE / EQUIPMENT l 0423-2637 A VITR0 LABS. l- 1MS-28-296-0 DOCUMENT TITLE

~

TIME DELAY-ONE SHOT REFERENCES CMOS Integrated Circuits, Motorola Inc.,1978, Page 7-54.

DISCREPANCY The subject document shows connections to U2, U3, U5, U6, U8, and 09, MC14017, decade counter / dividers, and identif.ies pin 13 of each device as the inverse of " CLOCK EN." However, the reference data book indicates that pin 13 of the devices is the inverse of " CLOCK EN."

ASSUMED CORRECTION Delete the inversion bubble or remove the inversion bar from pin 13 of U2, U3, US, U6, U8, and U9.

l REPORTED BY DATE CUSTOMER ACTION

- Vitro agrees with the recommended correction.

B D E/N D ls?&?%*M^* 9.s i -

D2-118698-1 PROJECT SCEAG LOAD SEQUENCER PAGE 1 OF 1 DRAWING ERROR REPORT - 4 DOCUMENT NUMBER REV VENDOR MODULE / EQUIPMENT 0423-2579 A VITRO LABS. 1MS-28-277-0 DOCUMENT TITLE

~

CLOCK CARD REFERENCES VSMF Design Engineering Series, Cartridge 2449, Frame 1445, Excerpt from Motorola MHTL MC660 series Data Bock, 1974.

DISCREPANCY

1. The subject document shows connections made to U15-U19, MC663 Type, Dual J-K Flip Flops, and identifies pins 3 and 11 as the inverse of "R." However, the reference data book indicates that pins 3 and 11 of these devices are the inverse of "R ."

2. The device U4-07, a MC684, decade counter, of the subject document does not include inversion bubbles to pins 1, 2, 5, 10 and 14. However, the reference data book shows the inversion bubbles to pins 1, 2, 5, 10, and 14.

ASSUMED CORRECTION

1. Delete inversion bubbles or the inversion bar from pins 3 and 11 of U15-U19.

2. Add inversion bubbles to pins 1, 2, 5,10, and 14 of U4-07.

• REPORTED BY C Lee ON DATE _ 8/26/81 CUSTOMER ACTION Vitro agrees with the recommended correction.

E M E / X M fcljfr E E d '

• D-6

D2-118698-1 PROJECT SCE&G LOAD SE0VEllCER PAGE 1 OF 1 DRAWING ERROR REPORT -5 DOCUMENT NUMBER REV VENDOR MODULE / EQUIPMENT 2544-1013 VITR0 LABS. , IMS-28-254 DOCUMENT TITLE E.S.F. LOADIf1G SEQUEflCER ELECTRICAL SCHEMATIC, VIRGIL C. SUMMER f1VCLEAR STATI0tl

, REFERENCES DISCREPANCY Within the subject document, a nuraber of bubble signal name discrepancies were noted. Table 1 is a list of these discrepancies and the assumed corrections.

ASSUMED CORRECTION Table 1 Bubble # Sheet # Revision Existing Label Assumed Correction 56 3,5 3,2 SEQ ST-8 STEP 8 86 18 1 ATO-26 (SEQ 1HZ) ATO-26/(SEQ 1HZ) 222 19 1 1 + 11 01

• REF'ORTED BY P. Scarlato k cag[ ,

DATE 11/5/81 CUSTOMER ACTION Vitro agrees with the recommended corrections.

B D E/ N G M,y &M** o.7

l D2-118698-1 PROJECT SCE&G LOAD SEQUENCER PAGE I OF I DRAWING ERROR REPORT- 6 DOCUMENT NUMBER REV VENDOR MODULE / EQUIPMENT 2544-1013 VITR0 LABS. 1MS-28 254 DOCUMENT TITLE E.S.F. LOADING SEQUENCER ELECTRICAL SCHEMATIC, VIRGIL C. SUMMER NUCLEAR STATION

,, REFERENCES DISCREPANCY

. In the analysis of circuit functions, it has become apparent that the signal names for bubbles 52 & 208 are unprecise (52 = "PWR ON CLR" &

208 = "AT PWR ON CLR"). 1.) Bubble 52 is part of the automatic test fault reset circuit and should be labeled so as to correspond to an I automatic test reset. 2.) Bubble 208 is part of the power on clear circuit which is not a function of the automatic test circuits. Therefore, the signal name on bubble 208 should not contain the "AT" reference.

ASSUMED CORRECTION In the subject drawing:

1.) Relabel bubble 52 on sheets 3, 4, 8, & 22-example AT FR/P0C 2.) Delete the "AT" from bubble 108 on sheets 17, 21, & 22.

e REPORTED BY P. Scarlato ,d' - 4*/[' DATE 11/5'81'

/

CUSTOMER ACTION

~

Vitro agrees with the reconmended corrections.

B D M N G L9ss'hn'* o.a

D2-118698-1 PROJECT SCE&G LOAD SEQUENCER PAGE 1 OF 1 DRAWING ERROR REPORT - 7 DOCUMENT NUMBER REV VENDOR MODULE / EQUIPMENT SP-569-044461-000 JAN/14/76 SCE&G

-DOCUMENT TITLE

~

E.S.F LOADING SEQUENCE CONTROL PANELS, VIRGIL C. SUMMER NUCLEAR STATION

, REFERENCES Automation Industries Inc., Vitro Labs Div., Dwg. No. 2544-1013,

" Engineered Safety Features Loading Sequencer Electrical Schematics, Virgil C. Summer Nuclear Station ."

DISCREPANCY Parts of section 2:06.3 of the subject specification do not agree with the functions being perfonned by the referenced schematic. An example of this being in paragraph 4 of the above mentioned section, states that " Steps 2 and 8 are not initiated by the blockout sequence signal."

However, circuitry that would perform this, blocking function cannot be found in the referenced electrical schematic.

ASSUMED CORRECTION The referenced schematic is assumed to be correct and the subject document is assumed not to iiave been kept current with changes.

REPORTED BY J. L. Gallaway ,[, Mb4g DATE 11/6/81 CUSTOMER ACTION

. South Carolina Electric & Gas Company has indicated that the above referenced specification is in fact a preliminary document. Further, the document detennining the load sequences actual form fit and function was the Bill of Materials Specification, which was not provided to Boeing until after this report was submitted.

i l

88MNE$ eel $ME7 D-9

D2-118698-1 PROJECT SCE&G LOAD SEQUENCE,: PAGE 1 OF 1 DRAWING ERROR REPORT - 8 DOCUMENT NUMBER REV VENDOR MODULE / EQUIPMENT 0423-2674 0 VITRO LABS. 1MS-28-254 DOCUMENT TITLE

~

DECODING CARD NO. 3-4 ELECTRICAL SCHEMATIC DIAGRAM ,

REFERENCES Motorola Semiconductor Products Inc., Data Sheet for the MHTL MC684 Decade Counter.

DISCREPANCY In the subject drawing, device U1, U7, U13 & U14 (MC684) show the Carry-Out (CO) as pin 13. However, the referenced data sheet indicates that the Carry Out should be pin 12.

ASSUMED CORRECTION Relabel the subject drawing to show the Carry Out of devices U1, U7, U13 &

U14 to be pin 12.

• REPORTED BY P. Scarlato 43 ,

, IC(' '

DATE 11/5/81 CUSTOMER ACTION Vitro does not recommend a change on the basis that (CO) is a signal name and not a pin label.

Boeing agrees. but recognizes that this signal convention may introduce confusion in future design updates.

B D E/ N G 85?fe5'%M*" 9_39

D2-118698-1 PROJECT SCE&G LCAD SE0VENCER PAGE I OF 1 DRAWING ERROR REPORT - 9 DOCUMENT NUMBER REV VENDOR MODULE / EQUIPMENT 1MS-94B-452-0 JUNE /1977 VITRO LABS. IMS-28-254 DOCUMENT TITLE INSTRUCTION MANUAL FOR EMERGENCY SAFETY FEATURES LOADING SEQUENCER CONTROL' PANELS, VIRGIL C. SUMMER NUCLEAR STATION y REFERENCES Automation Industries, Inc. , Vitro Labs. Div. , Dwg. No. 2544-1013,

" Engineered Safety Features Loading Sequencer Electrical Schematics, Virgil C. Sumer Nuclear Station ," sheet 1-3 and 21-2.

DISCREPANCY In the analysis of the function of the TIf1E DELAYS /0NC SH0TS, it was observed that Table 2 of the subject document is in conflict with the referenced drawing; these conflicts are listed in the table below.

TD/OS TIME ADJ - CORRECTIONS -( j Function Slot No. TDC Close PC SW Time Delay I Base BOS RESET DELAY 38 2 9 <*_2.7_SEC 3.0 SEC G7.0 SEC',

PASS LAMP DURATION 22 2 2.0 SEC 1.0 SEC AUTO TEST 4'2.>

23 3 3 g 3Q0_.Q dSEC,_ _10.0_.0 fS_E.Q

' 2_4Q.0. ESEE

, 60 0. MSEC.>

ASSUMED CORRECTION Revise Table 2 of the subject document with the corrections indicated above.

• REPORTED BY P. Scarlato (L 4 .

DATE 11/6/81 CUSTOMER ACTION Vitro agrees with the recommended corrections.

I 88MNEESEl$EE* D-11

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02-118698-1 1

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f APPENDIX E i

RESPONSES TO REPORTED ITEMS 3

(as received by Boeing from South Carolina Electric & Gas Co.)

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4 AUTOMATION INDUSTRIES,lNC. VL-cS-T-101 VITRO LABORATORIES DIVISION (Job 02544) uococsonc!A AVE * -

$!tVER SPR:NG f *.ARYLAf40 20910 (30tJ 8717200 August 25, 1981 6

Hr. James A. Uactor Director, Electrical /I&C Engineering South Carolina Electric and Cas Company Post Office Box 764 Columbia, South Carolina 29218 V. C. Summer Nuclear Station ESF LOAD SEQUENCER Sneak Circuit Analysis File: 16.621 .

D, tar Hr. Uactor:

Vitro Laboratories Division is in rece'ipt of yc . IcttL v~T Au sust 17, 1981 and the attached " Design Concern Report No. 1". The design is as intended,-and no action is required.

The design intent was to provide " pull-up resistors" on pins 1 . , -

through 5 and 11 through 15 of the 11C676P packages. The assembly method utilized 1.s commonly referred to as " piggy-back"; that being, one inte-grated circuit package nounted on top of another. In this case, the resistor package U18(U19) is mounted on top of the IC package U2(U8) in such a manner that pins 1 and 14 of U18(U19) correspond to pins 1 and 16 cf U2 (US) . Pin numbers for U18(U19) are id,entified with respect to the pin numbers of U2(U8). The resistors connected to pins 6, 7, and 10 are there only as a result of the assembly method used, and not intended to have any effect on circuit operation.

If you have any need for further technical information concerning this matter, please feel free to contact !!r. James J. !!oran at (301) 871-2560.

o Very truly you'rs,

.h. r<.

, C. E. Suer Department head CS, Department JJH:Im

._Di s t ri bu t i on SCE!,C/J AWac to r E-2 '

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@ AUTOMATION INDUSTRIES,INC. VL-CS-T-109(81) drP VITRO LABORATORIES DIVISION (Job 02544)

J.) 3-' 14000 GEORGIA AVE t' SILVERSPRING MARYLANO20910 October 20, 1981 LL (301)871 7200 er Mr. James A. Wactor, Director Electrical /I&C Engineer South Carolina Electric and Gas Company Post Office Box 764 Columbia, South Carolina 29218 V. C. Summer Nuclear Station ESF LOAD SEQUENCER SNEAK CIRCUIT ANALYSIS P.O. SN10214-SR File 16.621

Dear Mr. Wactor:

In response to your letter of September 29, 1981 concerning Boeing

' Aerospace Company Drawing Error Reports Nos.1 through 4 and Sneak Circ.uit Analysis Report No.1, please be advised of the following:

4 (a) Drawing Error Reports Nos. 1, 3, and 4 Vitro agrees that the typographical errors deecribed exist, and concurs that the recommended corrective actions should be imp?emented in accordance with the first paragraph of your letter.

(b) Drawing Error Report No. 2 Vitro disagrees with the discrepancy as described. The node on Sheet 12 is Node 33 and not Node 24. The node was identified as Node 24 and labeled as Step 1 on Comment Issue 1 of the schematics, but was later changed to Node 33 and labeled Step 1 and appears this way on the "as-built" drawings. See Comment (c).

(c) Sneak Circuit Report No. 1

, The electrical connection between Circuit Card XA3-Pin 21 and the 115 y a.c. does not exist and there is no danger of equipment damage. The error was the assignment of 33 to the nodes connect-

~

ing XA3-Pin 21 on Sheet 5 to XA41- Pins 16 and 26 on Sheet 12.

(The change referenced in (b) above.)

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n D2-118698-1 AUTOMATION INDUSTRIES.INC. VL-CS-T-109(81)

.y VITRO LABORATORIES DIVISION (Job 02544) w 3

October 20, 1981 The node numbers are used for computer generation of wire lists from the schematics during initial equipment design. Diagnostic routines are employed to assure that the initial schematics do not contain errors which would cause incorrect wiring such as described in the Sneak Circuit Report.

Changes occurring during equipment test are documented by hand for indi-vidual drawings. These changes are not recycled through the computer to correct the schematics or wire lists. The schematics and wirc lists are individually corrected by hand. The possibility exists therefore that an error could be made in correcting the schematic which would appear as a wiring error. This error would not exist in the equipment. Additionally the equipment necessarily is completely tested prior to delivery thereby eliminating the possibility of a delivered wiring error.

Assignment of node numbers is arbitrary. Therefore Vitro suggests that Node 33 on Sheet 5 and Sheet 12 be changed to Node 125, which appears to be an available and presently unused number.

South Carolina Electric and Gas Company she.uld provide their vendors such as Boeing Aerospace Company with the latest drawings to preclude erroneous reports such as DER-2 and SCR-1.

If you have any need for further technical information concerning these matters, please feel free to contact Mr. James J. Moran at (301) 871-2580. -

m Very truly yours, C. E. Suer Department Head CS Department JJM:hmm Distribution SCE6G/JAWactor b

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D2-118698-1

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O AUTOMATIONINDUSTRIES,INC. vt-CS-T-2(82)

Z VITRO LABORATORIES DIVISION (Job 02544)

-// ?4000 GEORGIA AVE SILVER SPRING. MARYLANO 20910 January 12, 1982 w (301)a717200 Mr. James A. Wactor Director Electrical /I&C Engineering South Carolina Electric and Gas Company Post Office Box 764 Columbia, South Carolina 29218 V. C. Summer Nuclear Station ESF LOAD SEQUENCER SNEAK CIRCUIT ANALYSIS P.O. SN-10214-SR ,

File 16.621

Dear Mr. Wactor:

Vitro Laboratories Division has received a copy of the Preliminary Sneak Circuit Analysis Final Report sent by South Carolina Electric and Cas Company, and has the following comments on this report. 'In' addition to DER No. 7 Sections 6.0, 7.0, 8.0-a and 8.0-d, and ^^" "- ' -1s:

appear to be outside Vitro's scope of legitimate comment and, therefore, are not addressed. Additionally, comments to SCR No. 1, DCR No. 1,and DERs Nos. 1, 2, 3 and 4 have been transmitted in VL-CS-T-109(81) on October 20, 1981, and also are not addressed.

Sections 8.0-b and 8.0-c The practices suggested are common for digital systems utilizing high-speed logic families such as TTL where speed of operation is a primary design goal. The. Load Sequencers use MHTL which is a relatively slow logic family designed primarily to provide a high level of noise immunity. Additionally, Vitro's design practices provide resistor-capacitor noise filters throughout the logic and multiple path power supply wiring to enhance the system's noise immunity for this type of slow-speed system in l the same manner as the suggested practices do for a high-speed system. l Section 8.0-e e

The circuit condition described is correct. A caution note concern-ing the possible occurrence of a redundant time delay setting is contained on pages 25 and 28 of the Instruction Manual. Any change in the switch l settings must be followed by a verification test to verify the new settings. i E-5

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D2-118698-1 l ," OD l -:.

9 AUTOMATION INDUSTRIES,1NC. VL-CS-T-2(82)

VITRO LABORATORIES DIVISION (Job 02544) d Janu.ary 12, 1982 l i

SCE&G/J. A. Wactor l

- Section 8.0-f The circuit condition described is correct. Any input from the plcat is considered to be an abnormal condition with respect to the Automatic Test Features. Also, annunciation of abnormal equipment conditions occur-ring while the equipment is performing its safety function is beyond tiie c ope of the Automatic Test Features.

SCR-2 Vitro disagrees that a sneak circuit exists, but rather considers this to be a drawing error on Sheet 2, Zone 3A, of Vitro Drawing 2544-1013.

The actual driver connections to the BKR Status Indicators are reversed-from those shown on the drawing. The actual connections are J3-C to XA42-41 and J3-D to XA42-27, as shown in Nets 1010 and 1020 of the Card File Wire List, Vitro Drawing WL 2544-1007. Vitro recommends that Drawing 2544-1013 be corrected by correcting the wire connections. Vitro.recom= ends against changing the labels, as this would make Drawing 2544-1013 disagree with the actual control panel labels and reference designations as they

. exist on the cabinets.

SCR-3 The circuit condition described appears to be the result of a Gilbert and/or SCE&G drawing change error. The connection point for Bubble 260 is at XA11-58 shown at Zone C7 on Sheet 20 of Vitro Drawing 2544-1013. Vitro E.O. 41341 dated July 30, 1980 and incorporated by Gilbert and/or SCE6G, made a change in Zone D7 of Sheet 20 but did not eliminate the signal source of Bubble 260. Electrically, the connection exists and no wire changes are required. Vitro recommends thet Vitro Drawing 2544-1013 be corrected.

SCR-4 -

Relay K80 is incorrectly listed in the Instruction Manual spare parts list as a 120 v a.c. relay. Vitro recommends that the listing be changed to show K80 to be the same as K67, a Potter /Brumfield KUP14D15-24VDC, 3-pole relay. This will make the same spare parts list in the manual consistent with the parts list on ESF Loading Sequencer Control Panel Assembly Draw-iag, Vitro No. 2544-1005, Sheet 3. The correct relay is installed in the equipment and a part change is not required.

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'. AUTOMATION INDUSTRIES,1NC.

VL-CS-T-2 (82)

~7 VITRO LABORATORIES DIVISION (Job 02544) 4 January 12, 1962 e

SCE&G/J. A. Wactor DCR-2 4

Motorola's published literature does not carry any information concerning the necessity for connecting the four-input expander package common pin to circuit common. The literature does indicate that these diode array circuits can be used in the same manner as discrete diodes, observing of course, proper voltage and current limitations. It is in this manner that they are used in the Load Sequencer design. Vitro does not recommend a change.

DCR-3 The diodes were originally part of the Automatic Test circuitry, but later Purchaser-initiated functional design changes obviated them.

They were not removed to minimize the wire changes necessar~ to imple-ment a required field design change. Vitro does not feel tueir removal would add significance to system reliability. ,

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DCR-4 -

Capacitor CU8-7 is sized with respect to the digital circuit's switch'ing speeds to preclude spurious clock pulses. Vitro does not recommend a change.

DCR-5 This design concern report is incomplete because it does not demon-strate quantitatively that the +13 v d.c. power supply circuits can pro-vide the power required to maintain relay K80 in the energized state should the +24 v d.c. power supply fail. Also, if the system will not respond to normal inputs, as stated under the potential impact statement, neither will it respond to auto test inputs which will result in relay K80 being deenergized by the auto test fault circuits and immediately annunciating a cabinet malfunction. Hence, Vitro does not recommend any circuit modification of the system unless the results of a more detailed system operation / circuit analysis verify the validity of this design concern report.

DER-5, 6, 7, and 9 o

Vitro agrees with the drawing corrections as shown on these four Drawing Error Reports.

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.VL-CS-T-2(82) ,

VITRO LABORATORIES DIVISION (Job 02544)

January 12, 1982 SCE&G/J. A. Wactor .

l DER-8 4

The reference drawing is not in error and no change should be made.

The component pin brought to the card edge connector is Pin 13, not Pin

12. The label (CO) identifies the output as it is used within Vitro's building block scheme of system design.

Vitro recognizes that the documentation changes required by SCR-2 and SCh-4 are Vitro's responsibility and will make the changes. The corrected documentation will be sent to SCE&G in accordance with the original contract requirements for type and distribution of the "as-built" documentation. _

With your receipt of this letter, Vitro has fulfilled its responsi-bility as the equipment supplier in supporting the Sneak Circuit Analysis on the ESF Load Sequencer. Vitro would be pleased to provide a quotation for any additional engit. . * . ... . *.es .2 quired by SCE&G concerning the Load Sequencers. Technical information concerning the design, operation, maintenance, or troubleshooting of the equipment is of course, always available via telephone inquiry.

If you have any need for further technical information concerning Vitro's comments to the ESF Load Sequencer Sneak Circuit Analysis Report, please feel free to contact Mr. James J. Moran at (301) 871-2580.

Very truly yours,

, .)

C. E. Suer Department Head ,

CS Department

, JJM:fm Distribution SCE&G/JAWactor l

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[ Gilbert / Commonwealth engineers and consuttants GILBERT ASSOCIATES. INC. P. 0 Box 1498. Reading. PA 19603. Tet 215 775-2600< Cable Gilasoc/Teles 836 431 March 22, 1932

, CGGS - 26783 4

Mr. C. A. Price, Manager Nuclear Engineering '

South Carolina Electric and Gas Company Post Office Box 764 Columbia, South Carolina 29218 Re: Virgil C. Summer Mucicar Station Unit #1 ESF Load Sequencer Sneak Circuit Analysis File Code: 15.RK

~

Response Code: NRR Ref: (1) CGSG-10093 (2).CGGS-25453 (3) CGGS-26688

Dear Mr. Price:

. 2 .

The sneak circuit analysis performed on the ESF Load Sequencer raised several questions that require GAI comments.' The. referenced Boeing

• reports and our comments are as follows: .

1. DER #7 This report notes a discrepancy between the system design and the specification. The system was purchased and operates as required. Since specifications are not design documents, they have not been revised and are not required to be kept up-to-date.

2. DCR'#6 This report states that a single point failure could result in the inhibiting or initiating of an output. Any fault that results in an output would be detected by the operator via instrument indications and alarms. The operator would then determine if the output was due to a fault and take the o

necessary action. A failure that prevents an output does not degrado plant safety since two redundant Class lE cabinct's are provided. It is not postulated that the same fa' ult' would o occur in both cabinets at the same time. Sufficient redundancy is provided for the safety related systems such that a failure of any one train does not affect plant safety. Therefore. any sin::le point f ailure in the Load Sequencer does not degrade the safe operation of the plant.

5?5 tance,ter Asense. Re.edg PA Wsgantame pas erres R% Acadq PA Ft5 Il$ ?Gil

?tfl(s.4 esJ.e.qton A.rvn.e am a an, WI S11 ihi .sul t0 P.ce f.trut kw Twt. hv ."t? Au? t>DC E-9 .

D2-1186.98-1 Mr. C. ,A. Price SCE&G CCCS-26783

[ilbotdCe.. . _.. . alth mv w e March 22, 1982

• maar a:socarn = e o e == s n a r. n m.w c %, .

page 2 Reports DER #9 and SCR #4 require changes in the equipment instruction manual (CAI 1MS-94B-452-0). SCE&G is advised'to make these revisions in their instruction manuals as the manuals will not be revised and reissued.

O All other drawing changes required by the sneak circuit analysis have been issued and transmitted by references 2 and 3.

Very truly yours,

.1J-. J c 6 G -

E. J. Siegel I & C Engineer G. . Braddick Project Manager

- EJS:GJB:mic ec: C. A. Price (2) ,

V. C. Summer E. H. Crews, Jr.

NPCF/h'hitaker -

D. R. Moore O. S. Bradham G. J. Braddick H. A. Hanning C. C. Kramer J. Galloway (Boeing)

E. J. Siegel e

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