ML20235Z524

Rev 0 to Wire & Cable Program Rept

ML20235Z524
Person / Time
Site:	Rancho Seco
Issue date:	06/30/1987
From:	Gough E, Knight S, Sandra Talley SACRAMENTO MUNICIPAL UTILITY DISTRICT
To:
Shared Package
ML20235Z500	List: ML20235Z496 ML20235Z524
References
GCA-87-090, GCA-87-90, TAC-65195, NUDOCS 8707270320
Download: ML20235Z524 (42)

Text

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To GCA 87-090 J

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WIRE AND CABLE PROGRAM REPORT

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1

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RANCHO SECO NUCLEAR GENERATING STATION 1

1 1

SACRAMENTO MUNICIPAL UTILITY DISTRICT SACRAMENTO j

i REVISION 0 JUNE 30, 1987 l

l PREPARED BY:

APPROVED:

I Yfhfjh/

4r CRTSDR0 GRAM C00RDIlirIOR

' MANAGER OF A3thtU D'EPARTMENT S.R. Talley Stu Knight

(

Ad W*)

l CRTS PROGRAM MANAGER MkflAGES OFNUCLEAR ENGINEERING l

E.J. Gough G.V. Cranston 1

h((

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2-P J

Ecciosure 2 To GCA 87-090 i

1 WIRE AND CABLE PROGRAM REPORT

)

l 1.

INTRODUCTION The Rancho Seco Nuclear Generating Station at plant turnover in 1975 had a cable population of about 14,000 cables installed mostly in ladder type cable tray and in steel conduit.

Since 1975 about 9,000 cables have been added while 3 few have been deleted.

In common with 811 large modern power plants in the United States, Rancho Seco tracks its raceway and cable data in a computerized prcgram run on a mein frame computer. The current program has an acronym of CRTS (Cable Raceway Tracking System) and perfonns some checks and calculations as well as recording and reporting data. CRTS has been in place since July of I

1980.

The orig 16a! cable population of 14,000 was installed by Bechtel Power Corporation (BPC). SPC was both designer and constructor. Until the CRTS program was put in place in 1980, the cable and raceway was tracked by a BPC Program EE-553. This program has been used for over 20 nuclear power plants.

2.

BACKGROUND DISCUSSION 2.1 INITIATING EVENTS Although some questions concerning CRTS completeness, missing CRTS l

cards and conflicting procedures were raised by resident inspectors as early as 1983, major concerns did not arise until 1985 and 1986, In 1985 questions arose concerning the degree of desigo control exercised following spurious at.tuations reported in LER 85-16.

In 1986 questions arose concerning the degree of control exercised during the installation process and the validity of 'as-built" j

information in the CRTS data base following issuance of LER 86-10.

Employee allegations regarding overfilled cable trays snd incomplete i

data in CRTS, added to the level of concern.

Identified problems are j

listed in the CRTS Action Item List [ Attachment (1)] with appropriate references.

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i To GCA 87-090 W1RE AND CABLE PROGRAM REPORT (Coatinued) 2.2 INITIAL ACTIONS Infr,fal action taken by SMUD was to initiate enhancement of the CRTS program in mid-1986 and to use the enhanced program to check for j

raceway overfills, violstions of separation criteria, intermixing of 1

instrument cables with power and control cable, and other discrepancies as listed in the Action Plan. Although a number of i

discrepancies were " bookkeeping" problems, generated by the j

enhancement, a significant number could, potentially, have been of l

real concern.

Identified discrepancies are documented in reports j

from the SMUD contractor [IMPELL] to SMUD and their (, dispositions i

described in Item 2 of the CRTS Action Item List and supported by l

calculations in SMUD files. Late in 1986 a decision was made to signal trace a significant sample of the approximately 2400 sa~Taty cables installed from 1975 through 1986 and compare the "as-built" condition with plant documents and the CRTS data base to establish a l

level of confidence in the re' liability of the data base. The signal i

tracing has found sufficient number of major defects in both Lot 1 (424 cables) and tot 4 (78 cables) to require 100% inspection of each lot.

In 1.ste Jun?, 1987 sampling is complete in Lots 2, 3 and 4.

However, in July,1987 a decision was made to sample Lot 2 to the "one-defect" level, increasing the size et Lot 2 by 35 cables.

Approximately 36" : ables remain to be checked in Lot 1.

Simply i

stated, the intent was to establish M percent confidence that the true percentage of discrepant circuit, in the sampled population is no greater than 5 percent.

Forecast completion is November 1,1987.

The current status is described in Item 1 of the CRTS Action Item List [ Attachment (1)]

I with further details provfded in the commentary.

2.3 ACTION PLAN Sf'UD has provided a document [ Appendix (2)] to the NRC which describes a five part Action Plan to consolidate the various activities of the Nuclear Engineering Department, which deal with the cable and raceway questions.

Although the scope of the plan is complete, the details and the individual actions require additional definition to enable a reviewer to easily determine the acceptability of the resolution of each item (i.e., question or issue raised).

The Wire and Cable Program Report is intended to replace the Action Flan and to provide additional definition and schedule information.

2.4 CRTS ACTION ITEM LIST AND COMMENTARY This report provides [ Attachment (1)] a listing of over fifty CRTS action items with a detailed commentary on each. This list is intended to serve as a record of all questions raf sed and of all known prob'lems.

For each item the list includes, an item number, description. Source, status and schedule for resolution, if appropriate.

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To GCA 87-090' 1

WIRE AND CABLE PROGRAM REPORT (Continued)

A commentary will be provided on each item covering chronology, generic implications, causes and corrective actions as appropriate.

This initial report only. contains commentaries on items 1, 2, 3, 4 19 and 20.

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~

l To understand the significance of each item it is necessary to read

-l the attendant commentary. The major concerns are summarized in the-J following section.

3.

MAJOR CONCERNS ISSUES CONCERNS Procedures The level of control exercised on cable installation.

Sampling Plan.

Accuracy of CRTS data on cable locations..

Data Base Completeness Omission of cables from data base.

Raceway Fill Control of. cable tray fill [ weight and ampacity questions].

Design Control Mixing of instrument cables [with power &

control] in design process, i

CRTS Discrepancies Control and entry of data.into CRTS.

Records Control of documents of record.

Miscellaneous Problems Completeness of licensee action in resolving problems.

Root Causes Identification and correction of all identified root causes.

Status of each issue is, in summary, as follows:

a 3.1 PROCEDURES i

Precedures in place during the original construction period are 6ddressed in Item 7 of.the CRTS Action Item List.

Procedures _in place from 1975 thru 1986 will be adoressed by the Incident Analysis Group [1AG] in closing Item 4 of the CRTS Action Item' List.

i 3,2 SAMPLING PLAN i

i lhis ' issue is fully addressed in the commentary to Item 1 of the CRTS Action Item List.

1 i

-3 t.

To GCA 87-090 WIRE AND CABLE PROGRAM REPORT (Continued) 3.3 DATA BASE COMPLETENESS The " completeness" issue of the CRTS data, centers on the data concerning the telephone and security cables.

This issue, although real, has no significant safety implications. The issue also includes questions concerning the verification of CRTS software.

l Items 10,11,12,13 and 14 of the CRTS Action Item List cover the completeness issue.

3.4 RACEWAY FILL The cable tray fill and weight questions have been reviewed.

Percentage fill and weights for all cable trays have been checked.

Although some relatively minor questions remain to be answered, no significant problems have been found.

Changes are planned to USAR which will reconcile differences between the USAR and Nuclear I

Engineering Procedures and will clarify design limits.

Enhancements planned to the CRTS software will, when in place, automatically prevent fill and weight limits from being exceeded.

These questions are addressed in Items 2 [ partial], 6 and 26 of the CRTS Action Item List.

l 3.5 DESIGN CONTROL l

l The design control issue is more complex than the raceway fill issue, I

but problems are limited to a relatively small number of instrument cables which mix with power and control cables and violate design criteria. No evidence has been found of a programmatic failure following a review of the original 14,000 cable population. Checking continues, but is not expected to change this current evaluation.

The question of a possible generic design problem in the original 14,000 cable population is addressed in Item 5 of the CRTS Action Item List. Other specific mix questions are addressed in Items 2

[ partial], 9, 43, 44, 45, 46, 47, 48, 49 and 50.

3.6 CRTS DISCREPANCIES The laroe number of CRTS discrepancies, listed by the SMUD contractor

[Impell: in Task #271, is another complex question. Although the large nunber is initially disquieting, upon examination none have any safety significance as detailed in the commentary on CRTS Action Item 2.

One example of this is the total of 763 reported mixes of Class I with Class 2 or 3 cables. Almost all the 763 cables are in the original cable population which permitted mixing and none violated safety criteria. All of the 1967 Class 1 discrepancies and some Class 2/3 discrepancies have been carefully analyzed, with 4

documentation, without finding any significant concerns.

The reason

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I i

To GCA 87-090 WIRE AND CABLE PROGRAM REPORT (Continued) for this, detailed in the commentary, is that the CRTS enhancements themselves generated the discrepancy lists which then had to be addressed. One benefit of the CRTS discrepancy process is that the l

total population of 23,000 cables and related raceways has been scrutinized closely and results provide additional confidence in the lack of significant safety concerns in the cable population. This issue is addressed in Item 2 of the CRTS Action Item List.

3.7 RECORDS Record control at Rancho Seco is a simpler issue. Tne customary industry documents of record for installed cable and raceway are the signed installation cards. The computer tracking system is used as a convenient source of data while the verification record is the installation card. At Rancho Seco the originals of the installation cards for the initial 14,000 cables and raceway have not yet been t

found, although facsimile record copies do exist. As discussed in the commentary to CRTS Action Item 3, we find that records for the 14,000 are apparently complete, although the clerical task of checkirq each cable and raceway card is not complete. Card records for the 9,000 cables and raceway sections installed after commercial l

operation are mostly complete. A search is being made for missing pull cards, of which 118 are safety related.

l 3.8 MISCELLANE0US PROBLEMS This issue deals with the completeness of SMUD actions in identifying and resolving all cables and raceway problems..

The CRTS Action Item List and commentary [ Attachment (1)] is the vehicle which records all questions and problems. All items with safety significance will be resolved before restart. All items with no safety significance will be resolved before the Cycle 8 outage.

l i

All items in the CRTS Action Item List will be reviewed for generic implications before resolution. When a concern has been identified, I

the basic steps taken by SMUD are:

1) Take immediate action to prevent repetition.

i

2) Identify the direct cause and take corrective action.

3) Investigate and identify the root cause, und if required, supplement the corrective action.

3.9 ROOT CAUSES Where applicable, root causes will be established for each item in the CRTS Action Item List.

The Incident Analysis Group [IAG] will

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To GCA 87-090 WIRE AND CABLE PROGRAM REPORT (Continued) establish root causes for issues identified during the investigation of problems encountered in the 9,000 cables installed 1975 through 1986. This issue is addressed in Item 15 of the CRTS Action Item List.

4.

APPENDICES 1.

Sampling Plan for Cable Raceway Tracking System Database (Impe11 Task 271, SMUD calculation No. Z-ZZZ-E0694, Revision 3 Dated March 17, 1987.)

~

2.

Rancho Seco Wire and Cable Program Description and Action Plan (District Submittal Dated April 3,1987 JEW 87-478).

5.

ATTACHMENTS 1.

CRTS Action Item List and Commentary (34 pages).

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To GCA 87-090

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ATTACHMENT 1 Page 6 of 34 ITEM LIST COMMENTARY ITEM NO. 1 i

DESCRIPTION Demonstrate that the CRTS recorded cable locations match "as-built".

COMMENTARY j

CHRONOLOGY Employee allegations and statements as early as 1983 indicated possible deficiencies in the CRTS data with the possibility of both missing and j

inaccurate information.

SMUD Nuclear Engineering Department [NED] actions were pulled together into a single Action Plan in January,1987. SMUD i

Incident Analysis Group [IAG] assumed responsibility for the root cause-I analysis of the CRTS problems and related LER's in April,1987.

In July,1986 NED authorized a contractor [Impell] to institute a review and evaluation of the CRTS program which would identify all data i

discrepancies, evaluate and document their significance and report to i

SMUD. Approximately 30,000 manhours have been expended on this effort to date and work is still continuing. Completion of this effort is Item 2 of the CRTS Action Item List.

In early December,1986, NED made a decision to signal trace a sample of safety related cables installed from 1975 through 1986.

This program is detailed in the Sample Plan [ Appendix (1)].

The plan is designed to statistically insure that the overall quality level achieves at least a 95% compliance with a 95% confidence level. A decision was also made not to signal trace a sample of the original 14,000 cables on the basis that the original designer / constructor Bechtel Power Corporation [BPC] had exercised an acceptable level of control. The supporting rationale for i

this decision is referenced in Item 7.

By late June,1987 the finding of ten major defects in Lot 1 initiated a complete inspection of all 424 cables, 360 of the 424 remain to be

checked, Sampling of Lots 2,3 and 4 is complete, except for the additional 35 cables required to bring the Lot 2 sample size to the "one-defect" level.

Population lot 4 consists of a group of 78 cables which were all signal traced. This was done because the signal tracing uncovered seven Appendix "R" cables which were documented as rerouted from Fire Area 36 to Fire Area 31, when this had not been done, as described in LER 87-13. These cables were part of the group of 28 cables installed under one ECN. This group includes the seven cables found with incorrect ' routes in LER 86-10.-

\\

To GCA 87-090 i

Pace 7 of 34 Item Noi 1 (Continued)

)

All cables in tnis group [28] have now been traced with the fourteen cables descrfoed having incorrectly recorded routes. Tne direct and root causes of the LER 86-10 and 87-13 Will be addressed by the SMUD Incident Analysis Group [IAG]. See the Item 4 commentary for the schedule.

GENERIC IMPLICATIONS l

With the completion of the Sampling Plan activity, SMUD will have established a 95 percent confidence that the CRTs data base is 95 percent accurate with respect to the location of the 2389 safe shutdown / safety 1

related cables installed from 1975 through 1986.

This is viewed by SMUD l

as acceptable and comparable with industry norms, i

The SMUD evaluation of the level of control exercised in installing the original 14,000 cables indicates a level of confidence at least equal to the 95/95 target for the 9000.

[See Item 7 of CRTS action item list].

New procedures and planned CRTS enhancements will be adequate to control the validity of CRTS "as-built" data. The " completeness" issue ccncerning i

CRTS data is a separate question and is addressed in Items 11 and 12 of i

the CRTS Action Its List.

1 CAUSES The root cause is stili under review. A factor is that over the period from 1975 through 1986, eleven years, different procedures have applied.

The IAG evaluation will address the effect of differing procedures on this item [ Item 4 of the CRTS Action Item List].

From the sampling plan results the "as-built" record appears adequate, l

CORRECTIVE ACTIONS The current process mandates that the installation of safety cables (Class I and Appendix "R") is witnessed by the QC inspector; this corrects a major deficiciency in past practice. A new procedure NEAP 4127 " Cable and Raceway Tracking System" was issued in June,1987 and controls the methods by which changes are made to the CRTS data base and the issuance and processing of all installation cards. Corrective actions will be reviewed I

after the IAG root cause analysis is completed. See the Item 4 commentary for the IAG schedule.

To GCA 87-090 Page 8 of 34 ITEM No. 2 DESCRIPTION Pesolve all CRTS data base discrepancies COMMENTARY CHRONOLOGY Since July,1986, a SMUD contractor [Impell] has been performing a review and evaluation of the CRTS data for the total population of 23,000 cables. This review has been conducted under control of the Impell QA Program and all results have been documented and submitted to SMUD for acceptance.

Progress reports have been issued, the most current of which is Report No.

20 dated May 29, 1987 The large number of discrepancies reported are not a cause for concern. Many are not real discrepancies but are

" bookkeeping" corrections.

Still others are caused by incorrectly applying current criteria to cables which were installed to older criteria. These " discrepancies" are therefore incorrectly reported end no discrepancy actually exists.

As explained in the Action Plan, SMUD will review, evaluate and disposition, with documentation, all Class 1 and Appendix "R" discrepancies prior to restart. Class 2 and Class 3 discrepancies will be dispositioned, in the same manner, after restart but before the end of the Cycle 8 outage.

GENERIC IMPLICATIONS Each discrepancy has to be evaluated separately.

The evaluations may be summarized as follows:

(Note that the Action Plan totals have, in some cases, changed as indicated.)

Class 1. Item 1.0 - Intermixing of Class 1/2/3 Cables (Total 763)

None of the 763 discrepancies are valid. The total breaks down as follows:

669 Are part of the 14,000 original cable and are correctly installed. This is because the original criteria allowed mixing, provided that no Class 2/3 cables " bridged" redundant Class I separation groups.

82 Are either deleted or are routed in "special" raceways se that no mixing occurs.

I?

Were installed post-1975 but under the original plant criteria.

All may be grouped with 669.

c

~

To GCA 87-090 Page 9 of 34 Item No.2 (Continued)

Class 1 Item 2.0 Overf111ed Trays (Power and Control) Total' 38 The 38 cable trays were reviewed to determine their fill at the time of commercial operation and their current fill with the results given below.

The 38 were checked for both ampacity derating and also for weight.

EE-553 CRTS EE-553 CRTS 10/14/75 3/9/87 10/14/75 3/9/87-Tray

,% Fill

% Fill Tray

% Fill

% Fill L43AZ3 44 42 M41F1 36 40 L44AK1 45 49 M41G1 34 38 L44AU1 41 42 M41H4 36 41 L44BF1 36 38 M41M3 42 44 L44BM2 17 40 M41P1 34 38 L44BN2 34 43 M41X1 39 40 L448Y3 47 49 M41Y1 39 40 L44CF1 45 51 M41Z1 31 40 L44P1 39 39 M43V10 47 40 L44P2 39 40 M43V11 34 37 L44V36 49 47 M44AU1 39 38 M39BA7 40 42 M44AY1 34 39 M40AM2 36 42 M44AY4 49 53-M40AQ2 37 42 M44V10 61 59 M41AA1 30 35 M44V11 36 43 H41AD1 34 39 M44V70 38 41 M41AE1 32 36 M45B1 48 45 M41AF1 32 36 M45V10 38 41 M41BD1 35 35 M45V8 48 42 An issue raised by the Resident NRC Inspector concerned the documentation of ampacity and weight checks. The specific question was "Did SMUD perf orm 10CFR50.59 reviews of overfilled trays 7" The review process for the original 14,000 cables and the later 9,000 added cables was as follows:

Original Installation Power and control cable trays filled in excess of 40% were checked to verify that the cable loading was not in excess of 50 lbs/ linear foot.

Instrumentation cable trays fified in excess of 60% were checked to verify that the cable loading was not in excess of 50 lbs/ linear foot.

Instrumentation cable tray fill between 40% and'60% was accepted based upon a generic calculation. -In addition, ampacity checks were made on all-power and control cable trays filled in excess of 40%. No documentation.

of the design checking has been found in Bechtel or SMUD files.

Retention of such documentation was not a common practice. - As detailed later in this commentary, all fills and weights have now been checked and documented.

w-e

To GCA 87-090 Page 10 of 34 Item No.2 (Continued) l Cables Installed After Commercial Operation Power and Control cable trays filled in excess of 40% were dispositioned -

l as described for the original installation, the cable loading was verified I

to be less than 50 lbs/ linear foot and the ampacity was checked. The results were not documented by calculation, and no formal reviews were I

performed to verify that weight limits were met.

Instrumentation cable I

trays filled in excess of 50% were checked to verify that the cable loading was not in excess of 50 lbs/ linear foot.

Instrumentation cable tray fill between 40% and 50% was accepted based upon a generic calculation.

The results of the instrumentation cable tray weight checks were also not documented and no fonnal 50.59 reviews were performed.

,Resul ts At this time, July 1,1987, all cable trays and conduits have been reviewed for fill and for weight problems.

Percent fill is a feature of the CRTS program.

Weight calculations were performed by a separate program run on a PC and performed on data " dumped" from the main computer.

Results are as follows:

Instrument Tray Fills The USAR limit is 40% versus the Nuclear Engineering design criteria which has a 50% fill limit for instrument cable trays. All trays have been checked for weight, regardless of fill level. No trays were found to exceed the USAR limit of 50 lbs/ linear foot.

Visual checks are being performed for " heaped" or " mounded" conditions indicating possible problems during a design basis earthquake. At this time no significant problems have been found.

The USAR fill limit will be changed to 50%.

Power and Control Tray Fills The USAR limit is 40%. All trays have been checked for weight, regardless of fill level. One Class 2 cable tray is overweight by 1.16 lbs and cables are being removed to delete the excess. No other trays have been found with "real" fills in excess of 50 lbs/ linear foot. A few " false" fills have been found which are in the process of correction.

" False" fills occur when iong tray sections include all cables in the weight calculations and exceed 50 lbs/ linear foot, even if some of the cables only run a short distance in the raceway section, whereas the weight borne between supports does not exceed 50 lbs/ linear foot.

Documentation is provided by Impe11 under Task 334.

Ampacity checks have been made on all power and control cable trays with fills in excess of 40%.

No ampacity problems have been found.

To GCA 87-090 Page 11 of 34 Item No.2 (Continued)

Summary of Overfilled Tray Review j

No significant problems have been found to dats. Final checks are I

required to check special conditions to verify that their impact is minimal:

Weight contribution from telephone / security cables.

Weight contributions fro'a fire wrapping and cable tray covers.

Causes of Overfilled Trays No significant problems have been found and there appeers to have been a j

reasonable degree of conservatism in the original design. Nevertheless, the lack of documented reviews in the period 1976 to 1986 is an omission in the design process which should not have occurred.

Enhancements j

planned for the CRTS software will, in the future, automatically block i

cable additions which exceed fill and weight limitations.

Class 1, Item 3.0 - Overfilled Conduits (Power / Control) (Total is 108 Was 107)

All 108 are either incorrectly recorded fills, because the "as-built" conduit is larger than recorded or are acceptable for other reasons (very short length). Quite obviously conduits cannot e^sily be overfilled, j

unlike trays, and all 108 have documented dispositions indicating a complete lack of either fill or ampacity problems.

Class 1, Item 4.0 - Overfilled Conduits (Instruments) (Total is 14; Was 13)

All 14 are dispositioned as false fills or similar.

No ampacity problems exist with instrument cables.

Class 1, Item 5.0 - Raceway Connections (Total is 293; Was 200)

The CRTS program established " linkages" or " nodes" to check that connecting raceways in cable vias did, in fact, connect. When nodes were missed, by designers making the drawing changes each missed node generated a discrepancy report for each cable using the via.

All missing nodes have been checked and the " bookkeeping" errors corrected.

Class 1, Item 6.0 - Duplicated Numbers (Total is 2; Was 35)

These are two " bookkeeping" errors both of which have been dispositioned as having no significance.

l l

l

)

To GCA 87-090 1

I 1

Page 12 of 34 l

Item No.2 (Continued)

I Class 1, Item 7.0 - Document Discrepancies (Total is 555; Was 551)

The 555 are a miscellany of minor data discrepancies dealing with entries l

covering equipment numbers, raceway numbers, cable codes, cable data (conductor size / number) and others. All have been checked and the data corrected as needed.

No data questions remain open.

Class 1, Item 8.0 - Tagging / Identification Discrepancy (Total is 0; Was 7)

The original seven items are now reported in the Item 5.0 totals.

Class 1, Item 9.0 - Missing / Unsigned Construction Cards (Total is 180; Was 53)

The 180 cards all exist but are missing signatures.

Three NCR's have been issued covering all 180. Dispositioning will require verification of terminations or cable / conduit locations, whichever is appropriate.

Termination and cable verifications, about 60, are complete. Conduit data will be verified prior to restart.

The following Non-Class 1 discrepancies have all been dispositioned without finding any safety problems.

Non-Class 1, Item 1.0 - Intermixing of Power / Control / Instrument Cables (Total is 400; Was 125)

The USAR wording requires separation of instrument cables from power and control cables for RPS and ESFAS. USAR does not clearly address mixing for other systems. USAR also does not address or define what constitutes l

instrument, control and power cables.

l SMUD Nuclear Engineering Procedures (NEP's, Criteria and Guides) also do l

not clearly define instrument, control and power cables. however, various types of signals (analog, digital) are discussed and digital signal cables are permitted to mix with control cables.

The NEP's will be revised to define instrument, control and power cables and explicitly detail the various service levels so that designers will l

have clear guidance on mixing.

The 400 reported Non-Class 1 mixes have been dispositioned as follows:

367 Accepted as meeting NEP's.

16 To be rerouted.

17 Which require drawing changes to clarify service level.

400 Total t

1 i

1' To GCA 87-090 l

Page 13 of 34 Item No.2 (Continued) l The original design process used twisted shielded pair (TSP) or coax /triax i

cables for all circuits considered as instrumentation. This has led to some confusion since no cable service levels are established in CRTS. A future CRTS enhancement will identify service levels for all cables.

Non-Class 1, Item 2.0 - Overf111ed Trays (Power and Control) (Total is 153 Was 131)

All trays have been checked for weight. Only one tray exceeded the 50 lbs/ linear foot USAR limit. Ampacity checks have been made on all cable trays with fills over 40%.

No ampacity problems have been found.

Non-Class 1, Item 3.0 - Overf111ed Trays (Instrument) (Total is 18 Was 19)

All trays have been checked for weight. None exceed the 50 lbs/ linear foot USAR limit.

Non-Class 1. Item 4.0 - Overfilled Conduit (Power and Control) (Total is 644 Was 639)

All 644'are either incorrectly recorded, because tne "as-built" conduit is larger than recorded in CRTS or are acceptable for other reasons. No ampacity prot,lems exist.

)

To GCA 87-090 Page 14 of 34 Item No.2 (Continued)

Resolution of Minor CRTS Data Discrepancies A number of minor Non-Class 1 data discrepancies exist. These are j

summarized below. None have any safety significance.

These data 1

discrepancies will be resolved after restart but not later than the Cycle J'

8 scheduled outage.

Non-Class 1 1.0 Overfilled Conduits (Instrument / Telephone) 151 2.0 Raceway Connections 1390 3.0 Duplicated Numbers 33 4.0 Document Discrepancy 1594 5.0 Tagging / Identification Discrepancy 130 j

6.0 Mis ing/ Unsigned Cchstruction Cards 92 l

Sub Total 4304 Securig 1

7.0 Raceway Connections 177 8.0 Duplicated Numbers 29 9.0 Documentation Discrepancy 276 10.0 Tagging / Identification Discrepancy 4

11.0 Missing / Unsigned Construction Cards 88 Total 4878 Causes of Discrepancies The enhancement of the CRTS software generated the list of discrepancies.

The discrepancies were caused by the data base conversion and errors l

entered into the data base in the 1980 to 1982 time frame.

{

The root cause of the CRTS problems will be determined by the IAG.

Both the design and installation processes will have to be examined to find out how data errors came to exist in such large numbers.

The level of control exercised is addressed in Item 4 of the CRTS Action Item List.

C_0RRECTIVE ACTIONS Major (safety related) discrepancies will be reviawed and dispositioned, 4

with documentation, prior to restart.

Minor (non-safety related) dir,crepancies will be reviewed and dispositioned, with documentation, prior to the end of the cycle 8 outage. Dispositionof each discrepancy will include verification that plant design documents, the CRTS Data Base and the "as-built" plant configuration are all in agreement.

\\

j

.m To GCA 87-090 Page 15 of 34 ITEM No. 3 DESCRIPTION Define SMbD document of record controllfug cable location.

COMMENTARY CHRONOLOGY la a January 7,1987 meeting, the Region V Electrical Inspector [Mr. Andy Hon] asked where cable pull cards are now kept and what bill be done with cable pull cerds in the future. To answer the question concerning SFlJD future actions required defining the SMUD document of record for cable locations. Answers to the two original cuestions and the additional definitions are as follows:

1.

NRC Question:

Where are cable pull cards now kept [ January, 1987]7 District Response: The cable pull cards together with equipment and raceway installation cards were kept in either locked metal card files in an office area of the "Bechtel Building",, which is a temporary on-site construction office or in boxes in trailers used as temporary offices.

2.

NRC Question:

What will be done with cable pull cards in the future [After January, 1987]?

District Response: The cable and raceway installation cards are new being kept in a " vault" in the "Bechtel Building". The record documents are a mixture of original card 3 and facsimiles when the originals cannot be found.

The vault is a secure, locked room with cement walls and a Halon Fire Protection System At this time, records are beirg checked to see how many cards are missing. When original cards are not found, facsimiles from the construction records will be substituted to create a complete record.

A duplicate record is being created on microfilm. During March and April 1987, about i

4500 cards were microfilmed and stored on the second floor of the T&R Building. Th's pror.ess 4

will continue until a complete duplic~te record a

is established.

i To GCA 87-090 l

Pace 16 of' 34 Item No. 3 (Continued)

Additional Information 1.

INSTALLATION VERIFICATION RECORDS FOR INSTALLED CABLE AND RACEWAY The Iristallation Verifict.tfon Records for installed cable and raceway I

are the " pull cards" and " raceway installation" cards respectively.

As of July 1, 1987, 118 Class I cable pull cards (originals or facsimiles) have not yet been located.

Full details of all missing cards (all types) are given in Section 4.

2.

ENGINEERING RECORDS FOR DESIGNED CABLE AND RACEWAY These records are the input documents to the CRTS program.

These are designated as "foms" and are engineering drawings by SMUD definition.

CRTS input drawings / forms are as follows:

E-1008 Raceway Input Document E-1010 Scheme Cable Input Document E-1026 Raceway Code Input Document i

E-1027 Cable Code Input Document j

E-1028 Electrical Equipment Input Document Originally new fonns were issued for changes. As of l

Jur.e 15,1987, all new cable and racsway input documents have been handled as Orawing Char;ge Notices.

Originals of input documents are being marked to show changes instead of issuing new forms.

3.

CRTS PROGRAM AND DATA BASE The function of the CRTS program and data base is two fold:

An engineering design tool which is used by the design group to a.

perform design check:: and calculations.

Currently the CRTS l

program checks for:

Raceway continuity Percentage fill Mixing of redundant separatica chhnnels Verifies raceway service levels for compatibility The CRTS is being enhanced to perform:

Weight calculations Checks on mixing of instrument cables with power and control cables i

l To GCA 87-090

{

j I

Page 17 of 34 Item No. 3 (Continued) l b.

A convenient data source which is used for engineering design infonnation. Typical uses of the CRTS generated infonnation are:

l Identification of cable routes 1

Calculation of totals of combustible materials (Btu totals) l Weight calculations for cable tray sections j

GENERIC IMPLICATIONS l

i Plant cables provide many diverse functions. The cables of safety systems i

provide both power supply and control functions as well as important indications to operators. The control and separation of redundant safety groups of cables and of all cables required for safe shutdown are l

important safety factors. The existence of reliable and accurate records I

concerning the location of the cables is essential to plant safety.

With the completion tf the Action Plan, SMUD will have established a record file of installation cards (originals and facsimiles) and a duplicate microfilm record. SMUD will also have confirmed that the CRTS data base is accurate to an acceptable confidence level.

With adequate maintenance of both records and CRTS data the necessary level of control will exist.

CAUSES Difficulties in tracing records indicate a need for greater management j

interest in record storage and an increased awareness on the part of SMUD employees of the importance of records.

l CORRECTIVE ACTIONS 1

l Replacement Cards:

Replacement cards will be generated, by CRTS, for all missing cards. The cards will be checked against the design documents.

Checked cards will be marked " Replacement Card" and the checker will sign and date the card.

Current Process: A new procedure (NEAP 4127) was issued in June, 1987.

This procedure is considered adequate to ensure that all cards are returned to CRTS.

4.

TOTAL NUMBERS OF MISSING CARDS The following are details of all missing cards as of July 1,1987:

To GCA 87-090 Page 17a of 34 ltem No. 3 (continued)

Cable Raceway Tracking System (CRTS)

ANALYSIS OF 1,800 MISSING CABLE CONSTRUCTION CARDS July 3,1987 Nuclear Nuclear Both Operation Engineering Depts.

Pre-ECN Total Missing Cards 797 - 44%

806 - 45%

61 - 3%

136 - 8%

....................m..............................-.....

' Pull' Cards 142 - 8%

177 - 11%

27 - 1%

2 - 0.1%

'From' Terminatf ore Cards 308 - 17%

146 - 8%

17 - 1%

3 - 0.2%

'To' Termination Cards 296 - 16%

193 - 10%

17 - 1%

3 - 0.2%

' Delete' Cards 51 - 3%

290 - 16%

0 - 0%

128 - 7%

...........................u..................................................

Total Cables in Data Base (CRTS Revision Level 1504) 23,218 Total Cables Having Missing Cards 1,072 Fraction of Cables Having Missing Cards 4.62%

Total Missing ' Pull' Cards 348 - 19%

Missing Class 1 ' Pull' Cards 118 -

7%

Total Missing ' Termination' Cards 923 - 55%

Total Missing ' Delete' Cards 469 - 26%

Total Missing Cable Cards 1,800 - 100%

p.

To GCA 87-090 Page 18 of 34 ITEM No. 4 DESCRIPTION Document the level of control exercised by SMUD in installing cable 1975-86 CHRONOLOGY Questions concerning the completeness of CRTS data, missing installation cards and conflicting procedures have been raised starting in 1983. The existence in 1978 of Quality Control Instruction QCI 107, which required the destruction of installation cards, raised questions concerning records.

Employee allegations and statements to the SMUD Ombudsman also tended to indicate some possible problems in controlling the installation l

process.

LER 86-10 identified 7 Appendix "R" cables which should have been relocated but were not. A SMUD Root Cause Analysis of this event is forecast for release in July, 1987. Additional analysis of the cable l

installation process is required to determine if root causes can be identified and lessons learned from them.

The SMUD Incident Analysis Group [IAG] has started their review of this item and has established a schedule cased on availability of information from the Nuclear Engineering Department.

i Forecast dates of other IAG investigations are as follows:

CRTS ACTION DESCRIPTION FURECAST ITEM 24 Determination of cause of redundant July, '87 cabling in same fire area (LER 86-10).

25 Determination of cause of redundant July, '87 instrument cables routed through l

same fire area (LER 87-13).

l l

So Description of the installation August, '87 procedures and practices used at Rancho Seco for the 9,000 cables added after commercial operation (1975-36).

55 Description of the events and LER 85-16 July, '87 circumstances leading to the LER 86-10 July, '87 misrouting of cable described in LER 87-13 July, '87 LER's LER 87-26 Aug, '87 56 Description of the events and July, '87 circumstances leading to the discrepancies discovered between the "as built" cable routes and the routes recorded in CRTS.

l l

To GCA 87-090

)

i i

Page 19 of 34

]

ITEM NO. 19 l

DESCRIPTION Provide basis for acceptability of 95/95 as sufficient assurence of safety.

j COMMENTARY CHRON0LCGY

)

The basis for 95/95 is given in the Sampling Plan [ Appendix (1)]. Cable sampling started in February 1987 and is scheduled for conipletion in

)

October, 1987.

Following a meeting with SMUD on May 6,1987 and a l

l subsequent telephone conference call on May 11, 1987 the NRC requested additional information.

SMUD RESPONSE l

The additional infctmation requested is provided in an appendix to this commentary. Once a joint agreement is established between the NRC and SMUD the Sampling Plan will be revised to reflect the agreement. The i

appendix has been prepared by a SMUD consultant [Impell] and:

i 1.

Provides information on established precedents.

1 2.

Provides additional information on the Technical Basis for the 1

l Sampling Plan and provides a comparison between the Rancho Seco I

Sampling Plan and Military Standard 10SD and related plans.

l

To GCA 87-090

. Attachment 1 Page 20 of 34 i

i APPENDIX

, ITEM NO.-19 PRIOR USE OF 95/95 ACCEPTANCE CRITERIA IN NUCLEAR POWER PLANT SAMPLING APPLICATIONS J

INVOLVING SAFETY-CLASS COMPONENTS 1

.There are nucerous prior instances where the NRC has approved the use of 95/95

)

sampling plans (i.e. plar.s which provide 95 percent confidence of 95 percent population reliability) for the sampling reinspection of safety-class J

components in U.S. nuclear power plants.

One of the earliest such precedents was provided by NRC I&E Bulletin 79-02, which permitted a 95/9G sampling plan to be used to demonstrate the adequacy of. installation of concrete expansion anchor bolts. More. recently, the NRC approved generic use of the 95/95 i

sampling plan proposed by the Nuclear Construction Issues Group in the document " Sample Plan for Visual Reinspection of Welds," (NCIG-02) Revision 2.

The following are specific plants that are known to nave employed 95/95 sampling plans w1th either NRC cone : rence or awareness:

Byron Braidwood Clinton San Onofre Unit 1 Vogtle Palo Verde South Texas Zimmer Midland Fermi Watts Bar

I To GCA 8f ORT TECHNICAL BASIS RANCHO SECO NUCLEAR GENERATING STATION, UNIT #1 SAFETY-RELATED AND SAFE SHUTDOWN CIRCUITS SAMPLING PLAN INTRODUCTION This paper describes the technical basis for the sampling plan developed to evaluate the routing of safety-related and safe shutdown electrical circuits

^

at Rancho Seco Nuclear Generating Station, Unit 1.

Subjects discussed include:

1.

The methed for determining minimum sample sizes required to satisfy pre-specified confidence itvel and circuit routing reliability.

.I criteria.

2.

Methods employed to select random samples of safety-related and safe shutdown ele:trical circuits corresponding to three different (non-overlapping) circuit populations, j

SAMPLING PLAN CHARACTERI7ATION The statistical methodology used to detennine sample sizes for three circuit populations at Ranch Seco is the likelihood density function method utilizing inspection by attributes.

This is one of several methods which can be used to

{

obtain a direct estimate of the percentage of discrepant items in a population from which a random sample has been drawn.

As described in Goodman

[ References 1 and 2], the likelihood density function is a normalized likelihood function:

f(ele) =

(Equatica 1}

)de where f(ele) =

the probability density function of the. unknown population parameter e

given observed sample evidence e, and L(ele) =

the likelihood of obtaining sample evidence e

given e In the case of sampling by attributes f rom a finite population, the likelihood function L(ele),is the hypergeometric distribution:

'N-mh l

[l-k'

(

{ Equation 2}

L(ele)=L(klm.n,N)=

n T6.GCA 87-OFJ ki m, k 5 n,.n 5 N, n-k i N-m where L(klm.n,N) = the probability of observing exactly k, discrepant k

items in a random sample of size n drawn from a population of size N that contains a total of m discrepant items.

In the case of sampling by attributes from an infinitely large population, the likelihood function L(ele) is tne binomial distribution:

In L(ele) = L(kln,p) = ik)/ Pk (3_p) n-k

{ Equation 3}

0 5 k s n, 0 5 p i l where L(kln,p) = the probability cf obtainir.g exactly k disertepant items in random sample of size n where the probability that a given item is discrepant is p.

Normalizing the likelihood functions given by Equations 2 and 3 as denoted in Equation 1, we obtain, for the finite population case,

[m)(Nd

\\ kl \\q-ki f(mlk,n,N) =

\\nl N- (n-k) i)/N-i*

[k/\\nok)

[

i i=k

[N'

\\nl 1

l N-m n-k (Equation 4}

=

% 11 l

(n+13 0 S k i n, k $ m S N - n + k, n $ N i

where c1 = the number of discrepant individuals in the population, k = the number of discrepant items observe.d in the 56mple, n = the sample size, and N = the population size 1

i

To GCA 87-090 For the binomial likelihood function L(kln.p), the corresponding likelihood density function is a beta distribution:

f(pln,k) = k!

! p (1 - p)"

, 0 $ k 5 n. 0 $ p 51

{ Equation 5)

~

n-I where n = sample size

]

k = the number of discrepant items observed in the sample, and 1

p = the f raction of discrepant items in the (infinitely large) population Using density functions 4 and 5, we can define the F fractile pp according to the formula l

PF F

f(ple)dp = F In the finite population case, this becomes "o

N - m\\

F(m 5 m,) = m=k N+1 I *o iN-n+k,

{ Equation 6) n+1./

with parameters as defined for equation 4.

In the corresponding infinite population case, P

o F(p$p)=[

_ -f, p g),p)n-k I

k dp (Equation 7) g 0

with parameters as defined for Equation 5.

4 i

~

To GCA 87-090 SAMPLE S?7E DETERMINATE,QN Equation 6 wss used to detemine sample sizes for sampling the three populations of safety-related and safe shutdown circuits at Rancho Seco Ruclear Generating Station Unit 1.

It was specified that samples should be chosen sufficiently large to provids 95 percent confidence that the true percentage of discrepant circuits in the populations f rom which samples were drawn was no greater than 5 per cent. This was achieved by:

1.

Finding the postulated number of discrepant items in the population that would be as close as possible to, but not exceed, 5 percent discrepant, i.e.,

"q $ 0.05 (m, an integer; N

l 2.

For a defined pcpulation size E and various possible values of k l

(k=0,1,2,3

-..n discrepant circuits in the sample), incrementally increase tne value of n in Equation 6 such that the computed value of 1

F(m 5 m ) comes as clase as possible to (but rever less than) the o

target value of 0.95.

This corresponds to a probability of 0.95 that j

l m

the true fraction of disefepant circuits in the population from which the sample was drawn, is no greater than 0.05.

In other words, l

l l

the sample size is chosch suf ficiently inrge to provide 95 percent f

l confidence that 95 percent cr more of tne circuits in each sampled I

population are routed properly.

1 SAMPLE SELECTION l

Random samples of circuits f rom each of tne three populations te be sampled i

were generated using a computer random nuinber gererator.

Within each population, simple random sampling without replacement was employed [ Reference 3).

Extra circuits were randomly selectea to serve as replacement samples in the event that ene or more circuits in the p'rimary samples were inaccessible or unusable.

Computerized circuit listings of the three populations to be sampled included some circuits which did nct belong to the population being sampled.

The population size provided to the computer random number generator corresponded including the to the total number of records (circuits) in the list extraneous circuits.

The extraneous circuits were manually removed from the computer-geneetted list.

All bona fide members of the population had an equal chance of being selected; the sample meets the statistical criterion of a simple random sample [ Reference 4].

I l

To~W8TM COMPARISON WITH OTHER TYPES OF SAMPLlNG PLANS The type of sampling methodology described above is different f rom (but no less technically valid than) acceptance sampling by attributes as employed in Military Standard 105D [ Reference 5).

Military Standard 1050 and related plans employ the statistical methods of hypothesis testing.

The likelihood density function method is based on the statistical method of parameter estimation.

While a

Military Standard 1050-type sampling plan is administrative 1y simple and amenable to use by persons unf ami_ liar with the underlying statistical theory, these plans were primarily intended to be used to_ help detennine a course of action -- not to estimate lot quality.

By design, such plans will end up accepting some lots with poor quality and rejecting some lots with good (even superior) quality.

Applying such a plan to an isolated population provides a simple " accept" or " reject" decision but no information whatsoever about the true lot quality.

The likelihood density f unction method, by contrast, yields a direct estimate of the lot quality, with the precision of the estimate improving as the sample size becomes larger.

It is therefore a true measure of our state-of-knowledge considering i

all of the available evidence.

A graphical representation of the likelihood density function method of determining minimum sample sizes is illustrated in two enclosed exhibits.

The 4

first exhibit, entitled " Likelihood Density Functions, Circuit Population 3",

i shows likelihood density functions for the number of discrepant circuits occurring in Population 3.

The different curves shown on the figure correspond to different sample sizes and sampling outcomes for non-replacement sampling from Population 3.

Each curve consists of data points denoted by '+'

symbols, and interconnecting lines of the same color.

The interconnecting lines are provided to aid the reader in distinguishing the general shape of the density function; however, only the '+' symbols have physical meaning since the population size is finite and the number of discrepant circuits must be an integer.

The above referenced figure illustrates how an increase in sample size increases one's state-of-knowledge about the true number of discrepant items in the population f rom which a sample has been drawn.

As the sainple size increases, the likelihood density function becomes narrower and more peaked indicating a sharpening of the precision with which the true percent discrepant in the population can be estimated.

If carried to its logical conclusion - by examining all items in the population -- the density function will continue to narrow and eventua'11y converge on the true value.

Prior to that time, the probability that the number of discrepant items in the population is less than or equal to some value m is given by integrating o

the corresponding area under the probability density function (infinite population case) or summing the individual terms of the probability mass function (finite population case).

Such cumulative probabilities for Circuit Population 3 are shown on the second exhibit.

The curves f or the dif f erent sample sizes and sampling outcomes are shown to converge at abscissa value m =9 and to pass above the 0.95 cumulative probability boundary at 5 percent o

discrepant.

Thus, all sampling outcomes (n=48, k=o; n=78, k=1;...: n=146, k=5) yield 95 percent confidence that the true percentage of discrepant cif cuits in Circuit Population 3 is 5 percent or smaller.

These com.binations form the basis for the multiple sampling plan developed for Circuit Population 3.

Equivalent procedures were used to develop the multiple sampling plans for Populations 1 and 2.

Enclo_sure 2 To GCA 87-090 SAMPLE SIZES COMPARED TO A '95/95' ACCEPTANCE SAMPLING PLAN Table 1 compares minimum sample sizes derived using the likelihood density function method and those for a single stage acceptance sampling plan designed to provide 95 percent confidence of 95 percent lot reliability.

The latter sample sizes were determined using the equation.

S Pr(acceptance) = Pr(k a lm.n,N)

{ [tk1 \\n-k1 m /N-mi an (Equation 8}

%n; k=o g

n = the acceptance number (a +1=the rejection number)

Were a n

k - the number of discrepant items in the sample (k=0,1, 2...a )

n

~

n = the sample size N = the population size m = the total number of discrepant items in the population, and m = the f raction of discrepant items in the population N

The table shows that for a single stage acceptance sampling plan with a =0, n

the required sample size is comparable to that determined using the likelihood density f unction method.

This remains true for higher values of a. as long n.

as the acceptance sampling plan consists of a single stage.

However, the two 3

methods yield divergent sample sizes when the acceptance sampling plan J

provides for two or more sampling stages.

For example, a two stage acceptance sampling plan with a =0 for the first stage, a =1 for the second stage, n

n and rejection at r =2 for both stages, will require a greater combined n

sample size than a single stage sampling plan providing for acceptance at a =1 and rejection at r =2.

This is in contrast to the likelihood density n

n function method, where the combined sample size for meeting the 95/95 acceptance criteria at either zero or one discrepant items appearing in the j

sample is identical to that for a single sample allowing one discrepancy. The dif ference between the two methods is attributable to the dif f ereate in the mathematical meaning of " confidence".

In acceptance sampling, " confidence" is the conditional probability of rejecting a lot containing

'X' percent

)

discrepant items, given that a lot of that quality has been submitted.

Using the likelihood density function method,

" confidence" is the conditional probability that the population f rom which the sample was drawn contains

'X' percent or fewer discrepant items, given the evidence available from the i

sample.

The latter is considered to be the more appropriate definition for

]

the sampling of isolated lots of installed components at nuclear power plants, and has the added benefit of allowing for multiple sampling with a smaller cumulative sample size than would be possible using acceptance sampling by i

attributes.

1 I

i To7 A 87-096 TABLE 1 COMPARISON OF '9565' MINIMUM SAMPLE SIZE'i FOR THE RACHO SECD UNIT 1 CIRCUIT POPULATIONS - LIKELIH000 DENSITY FUNCTION METHOD VER5US ACCEPTANCE SAMPLING BY ATTRIBUTES (SINGLE STAGE PLAN)

Method of Discrepancies Confidence Maxinun Percent Circuit Population Sample Size

. Allowed In Sanple Level (",)

Defective In The Population Size Detennination Sanple (a)

Size (b)

Population 1

424 Likelihood 0

52 95.081%

4.953%

Density 1

424 Acceptance 0

52 94.035%

4.953%

Sanpling 1

424 Acceptance 0

52 94.805%

5.189%

Smpling 1

424 Acceptance 0

53 94.372%

4.953%

Sanpling 1

424 Acceptance 0

53 96.112%

5.189%

Samling 2

1702 Likelihood 0

56 95.04 %

4.994%

I l

Density 2

1702 Acceptance 0

56 94.594%

4.994%

Sanoling

~

2 1702 Acceptance 0

56 94.781%

5.0535 Sanpling 2

1702 Acceptance 0

57 94.872%

4.994%

Sanoling 2

1702 Acceptance 0

57 95.053%

5.053%

Sangling 3

189 Likelihood 0

,48 95.350%

4.762%

Density 3

189 Acceptance 0-48 93.307%

4.762%

Sanpling 3

189 Acceptance 0

48 95.0925 5.291%

Smpling Notes: (a) For acceptance sanpling, this is equivalent to the acceptance ntseer; rejection would occur at 1 or more discrepant items in the sanple.

(b) For the. llPelihood density function method, " confidence level" is the conditional probability that the percent discrepant in the total population is less than or I

equal to the value shown in the last coltsnn, given the sapling evioence. For acceptance sangling, " confidence level" is the conditional probability of rejection of a lot with an incoming quality equal to the value shown in the last coltsnn, given that a lot of that quality has been sutsitted.

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1 To GCA 87-090 REFERENCES

[1] Goodman, J., 1984. " Sampling Inspection of Nuclear Power Plants."

Proceedings of tne 1984 Statistical Symposium on National Energy Issues, Seattle, Washington, October 16-18, 1984.

NUREG/CP-0063

[2] Goodman, J., 1985.

" Classification and Comparison of Sampling Procedures." Transactions of the 8th International Conference on Structural Mechanics in Reactor Technology, Brussels, Belgium, August 19-23, 1985

[3] Cocharan, W. G.,

1977.

Samplina Technicues, 3rd Edition.

John Wiley &

Sons, Inc., New York, New York, 128 p.

[4] Winkler, R. L., and W. L. Hayes,1975.

Statistics:

Probability.

Interference, and Decision, Second Edition.

Holt, Rinehart and Winston, New York, New York, 889 p. + Appendices

[5] Department of Defense, 1963.

" Military Standard-Sampling Procedures and Tables for Inspection by Attributes."

Superintendent of Documents, U.S.

Government Printing Of fice, Washington, DC.

MIL-STD-1050, 29 April 1963 4

)

I 4

i i

To GCA 87-090 l

Page 31 of 34 ITEM N0. 20 DESCRIPTION Resolve NRC concerns about possible biasing of sample.

1 COMMENTARY CHRONOLOGY Section 9.1 (3), Evaluation Process, of the Rancho Seco Sampling Plan l

concains the following statement:

)

l "If a deviation does exist oetween the CRTS database routing and the "as-built" routing, the results are first checked against existing CPR's or CON's to determine if tne devietion has already been dispositioned.

If this problem has been disoositioned by a CPR or CON, no defect for that lot exists."

The question was raised, by Mr. Faust Rosa, at the May 6, 1987 meeting as to whether the dispositioning of deviations, by CPR nr CON, introduced a bias into the sampling.

SMUD RESPONSE The response to the concern is provided in an Appendix to this commentary. The process described in Section 9.1 (3) is essentially only a correction of minor bookkeeping errors none of which impacted the cable route. Only seven cables had deviations which were dispositioned as described. All are detailed in the Appendix - and none had deviations which affected the route. No bias was introduced into the sampling by i

Section 0.1 (3). The appendix will be added to the Sample Plan in the next revision.

l i

r t

Jo GCA 87-090 APPENDIX TO ITEM #20 TABLE I

_ List of Circuit Tracing Walkdown Cables with CONS or CPRs The following list of cables are part of the CRTS circuit tracing sample cables and have CRTS problems identified as CONS (*) or CPRs(*).

Item Cable Work Request Number CON or CPR Designation 1

1GlQ886AR 108063 CON-0118 CPR-0053 2

1M1A137 C 127745 CON-0001 3

1P1A06 D

126992 CON-1018 4

1R1C260BB 128755 CPR-0865 5

1R1C469CL 127738 CPR-0031 6

1R2IR2H C 127006 CPR-0534 CPR-0672 7

111B314 A 127022 CPR-0866 o Conversion error reports (CONS) were generated for equipment, raceway, and cable problems identified from the June 1980 computer conversion error reports prepared by SMUD's contractor, Control Data j

Corporation, when Bechtel Power Corporation's EE-553 data base was converted to the present CRTS data base.

CRTS Problem Reports (CPRs) were generated for equipment, raceway, and cable problems identified after the June 1980 conversion.

~

l The following describes the problems and resolutions stated on the associated CONS /CPRs and their impact on the circuit tracing walkdown effort.

ITEM 1 Cable: 1GlQ886AR on CON-0118 and CPR-0053 Problems:

CON-0118 states that the CRTS raceway vias do not match Bechtel's EE-553 cable routing.

CPR-0053 states that the construction card's first and last vias (" red") do not match CRTS first and last vias (" white").

To GCA 87-090 l

~

)

l Table I _ (continued)

\\

Resolutions:

CON-0118 -- Junction box numbers were removed from CRTS vias and were confirmed by walkdown.

~

CPR-0053 -- Inspection verified the cable is painted with " red."

DCO has been issued to correct CRTS.

Walkdown Impact:

None on cable routing l

l ITEM 2 Cable:

1M1A137 C on CON-0001 Problem:

CON-0001 states that CRTS vias show cable tray L43V36 connecting to L39BN5, but CRTS raceway connections do not show them connecting.

Resolution:

CON-0001 -- CRTS Revision Level 1372, 02/16/87, raceway connections show Tray L43v36 connecting to L39BN5.

Walkdown Impact:

None on cable routing ITEM 3 Cable:

1P1A06 D on CON-1018 Problem:

CON-1018 states that "from" termination of cable does I

not match equipment I.D.

schedules.

l l

Resolution:

CON-1018 -

"From" termination is a section of a panel.

Panel is listed in equipment I.D.

schedule.

Walkdown Impact:

None on cable routing

)

ITEM 4 Cable:

1R1C260BB on CPR-0865 j

I Problem:

CPR-0865 states that CRTS shows the cable has a deleted status and removal of the cable is not verified.

Resolution:

CPR-0855 -- Inspection verified the cable is being spared and has been retagged to 1B1PA0101.

Walkdown Impact:

Cable is deleted.

New sample cable selected.

a

Em:losure 2 TB GCA 87-090 l

TableI (continued)

ITEM 5 Cable:

1R1C469CL on CPR-0031 Problem:

CPR-0031 states that the pull card is not signed by QC.

i Resolution:

NCR was issued and when dispositioned, the pull card will be signed by QC after inspection.

Walkdown Impact:

None on cable routing I

ITEM 6 I

Cable:

1R2IR2H C on CPR-0534 and CPR-0672 Problems:

CPR-0534 states that the cable is routed in Class 2 overfilled tray.

CPR-0672 states that the construction card has not been received and that the number of conductors does not match design drawings.

j Resolutions:

CPR-0534 -- Cables in overfilled tray were analyzed.

CPR-0672 -- Resolution of non-Class 1 problem on

)

unsigned construction cards is not completed.

Walkdown Impact:

None on cable routing 1

ITEM 7 Cabic:

111B314 A on CPR-0866 Problem:

CPR-0866 states that CRTS shows the cable has a deleted status and removal of the cable is not verified.

Resolution:

Inspection was performed and confirmed that the cable does not exist.

Walkdown Impact:

Cable is deleted.

New sample cable is selected.

l w____

.a