05000309/LER-1997-001, :on 970109,cable Separation II Occurred Due to Train Affiliation Labeling for Cables & Cable Trays Being Less than Adequate.Corrected Cable Discrepancies

:on 970109,cable Separation II Occurred Due to Train Affiliation Labeling for Cables & Cable Trays Being Less than Adequate.Corrected Cable Discrepancies

ML20138L577
Person / Time
Site:
Issue date:	02/18/1997
From:	Hebert J, Levesque M Maine Yankee
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
JRH-97-32, LER-97-001, LER-97-1, MN-97-23, NUDOCS 9702240413
Download: ML20138L577 (6)

LER-1997-001, on 970109,cable Separation II Occurred Due to Train Affiliation Labeling for Cables & Cable Trays Being Less than Adequate.Corrected Cable Discrepancies

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(ii) 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(viii)
3091997001R00 - NRC Website

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MaineYankee RELIABLE ELECTRICITY SINCE 1972 329 BATH ROAD e BRUNSWICK, MAINE 04011 + (207) 798-4100 February 18,1997 MN-97-23 JRH-97-32 UNITED STATES NUCLEA'R REGULATORY COMMISSION Attention:

Document Control Desk l

Washington, D. C.

20555 I

Reference:

(a)

License No. DPR-36 ( Docket No. 50-309 )

Subject:

Maine Yankee Licensee Event Report 97-001, Cable Separation H j

Gentlemen:

Please find enclosed Maine Yankee Licensee Event Report 97-001. This report is submitted in accordance with 10 CFR 50.73(a)(2)(ii) and 10 CFR 50.73(a)(2)(v).

Please contact us should you have any questions regarding this matter.

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Very truly yours, f

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James R. Hebert, Manager Licensing & Engineering Support Department mwf Enclosure j

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Mr. Hubert Miller Mr. J. T. Yerokun i

Mr. D. H. Dorman Mr. Patrick J. Dostle Mr. Uldis Vanags

1. Y) l 9702240413 970218 PDR ADOCK 05000309 S

PDR

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NRC,PQRM 3p6, u.S. NUCLEAR REGULATCRY COMMISSION APPROVED BY oMB NO. 3150-0104 (4-95)

EXPIRES 04/30/98 ESTIMATED BURDEN PER RESPONSE TO COMPLY WITH THIS I

MANDATORY IfRMMATION COLLECTION REQUEST: 50.0 HRS.

LICENSEE EVENT REPORT (LER)

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FOR COMMENTS REGMIDING BURDEN ESTIMATE TO THE INFORMATION l

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De digits / characters for each block)

TO THE PAPERWORK REDUCTION PROJECT (3150-0104), OFFICE OF FACluTV NAME (1)

DOCKET NUMBER (2)

PAGE (3) i l

Maine Yankee Atomic Power Company 50-309 1OF5

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CABLE SEPARATION 11 EVENT DATE (El LER NUMaER 16) 3 REPORT DATE (7)

OTHER FACluTIES INVOLVED IS) i FACluTY NAME DOCKET NUMBER SE U AL R

N MONTH DAY YEAR MONTH DAY YEAR YEAR NU NU R

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i 09 97 97 -- 001 00 02 18 97 FACluTY NAME DOCKET NUMBER 01 THIS REMRT IS SUBMMED NRSUANMO THE REQWREWNT i OF 10 UR O Ded one Or nm) MU CPERATING 3

MODE (9) 20.2201(b) 20.2203(a)(2)(v) 50.73(aH2)(i) 50.73(a)(2)(viii)

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50 n aH2Hm 50 n aH2H4 0

LEVEL (10) 20.2203(aH2)(i) 20.2203(a)(3)(ii) 50.73(a)(2Hiii) 73.71 20.2203(aH2Hii) 20.2203(aH4) 50.73(aH2Hivl oTHER se99

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low 20.2203(a)(2)(iv) 50.36(CH2) 50.73(aH2)(vii)

UCE*8SEE CONTACT FOR THIS LER (12)

NAME TELEPHONE NUMBER (include Area Code)

Mark A. Levesque, Nuclear Safety Engineer (207)- 882-5739

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i COMPLETE ONE LINE FOR EACH COMPONENT FAILUME DESCRIBED IN THIS REFORT (13) j T

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CAUSE

SYSTEM COMPONENT MANUFACTURER

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i SUPPLEMENTAL REPORT EXPECTED (14)

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No ABSTRACT (Umit to 1400 spaces, i.e., apprOximately 15 single-spaced typewritten lines) (16)

During the week of January 9,1996, while the plant was in the cold shutdown mode of operation, Maine Yankee engineers discovered additional cable separation issues. One (1) of these issues was determined to be an original construction issue, while others involve various components affected by the design modification process. These concerns were discovered as a result of the on-going reviews of cable separation issues identified in LER 96-038.

The conditions that were determined to be outside of Maine Yankee's cable separation criteria include the following: power cables were found encroaching different tray sections l cables from different vital buses and channels were found routed together or in the wrong tray sections; numerous cables of different trains or channels do not meet original separation criteria as a

.rssult of tray configurations at transition points such as risers and T's.

The discrepancies discovered during reviews have been or are in the process of being corrected or addressed. Some of the cables have been wrapped, separated, or re-routed in the correct section. Cable separation design and walkdown teams are in the process of identifying further actions or engineenng justifications for various conditions. Plant management is assessing long i

term actions to address causal factors identified by Plant Root Cause Evalaution #214, " Root Cause Investigation of Cable Separation Problems at Maine Yankee Atomic Power Co."

NRC FORM 366 (4~9b) m,

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NRCl FORM W U.s. NUCLEAR REGULATORY CoMMISSloN l

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j LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION f

FACluTY NAME (1)

DOCKET LER NUMBER (ii)

PAGE (3)

YEA SEQUENTIAL REVISI Maine Yankee Atomic Power Company 50-309 2

OF 5

TEXT (11 more space is required, use additional copies of NRC Form 366A) (11) f l

INITIAL PLANT CONDITIONS

On January 9,1997, Maine Yankee was in the cold shutdown mode of operation.

EVENT DESCRIPTION

During the week of January 9,1997, Maine Yankee engineers discovered eight (8) cable l

separation (FA) issues as part of the ongoing cable separation inspections:

i

1) The following two (2) cable separation issues were the result of plant modifications made to the DC Battery Bus system under Plant Design Change 2-81:

i a) 125VDC Battery Bus 5 cables which supply power for P-52 and P-53, the Air Side Seal

Oil Backup and Emergency Turbine Oil Backup Pumps, were found overlapping cable

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separation barriers (FA). This configuration appears to be the result of electrical system j

modifications made in 1981-1982 which created the DC Bus 5 NNS battery system.

Loads, such as P-52/53, were removed from DC Buses 1 and 3 and were re-routed to the l

new DC Bus 5. The cable routing discrepancy apparently occurred when it was determined the cables (CAB) were too short to reach the new DC Bus, in addition to the fact that the l

proper routing was blocked by a building support. Thus the cables, identified as 1811 and 1B90, were spliced and installed in cable tray "C." in this condition, they overlapped the separation barrier between tray sections "A" and "B."

b) Cables (CAB) removed from DC Buses 1 and 3 and re-routed to DC Bus 5 were found coiled in their respective cable trays. The cables were apparently too long to terminate into DC Distribution Panel No. 5. directly without adjusting for cable slack They were found coiled in their respective cable trays, thus jeopardizing separation across the tray section

_l separation barrier.

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2) Vital Bus 1 control power cables to the COMSIP Hydrogen Analyzer were routed in the same sleeve as the trip and indication power cables for the Emergency Feedwater (EFW) trip valves, TV-1205A, B, and C, from Vital Bus 3.

3) A 125VDC Bus 4 power cable for the Microwave Equipment cabinet was routed in a DC Bus 3 tray section. Cable 18228, which was originally specified to be routed in tray C22b was actually installed in tray C22c. Additionally, review of the specific original design separation criteria for this instance revealed that the cable should have been installed in tray C22d. This issue appears to be an original construction / design issue.

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NRC Fo,RM 366A U.s. NUCLEAR REGULATORY COMMISSION uceNsts event REPORT RER)

L TEXT CONTINUATION FACluTY NAME (1)

DOCKET LER NUMBER M)

PAGE (3)

YEA SEQUENTIAL REVISI M:ine. Yankee Atomic Power Company 50-309 97 -- 01

-- 00 TEXT (11more space is required, use additional copies of NRC Form 366A) (17l

EVENT DESCRIPTION

(Continued...)

4) Cables from Vital Bus 1 and RPS Channel B were found routed together. A 125VDC Vital i

Bus 1 feed to the Controlotron Emergency Feedwater (EP.'O tiow transmitters was routed in the same sleeve as the instrument cables for the LT-1224 Steam Generator (SG) #2

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Wide Range Level Transmitter, the FT-321 Loop 2 High Pressure Safety injection (HPSI)

Flow Transmitter, and the PS-2012B Containment High Pressure Trip Signal to the Reactor j

Protective System (RPS). All of the instruments, except for EFW flow, provide input to RPS i

channel B.

5) COMSIP Hydrogen Analyzer control cables were routed in the same cable tray as the Bendix Hydrogen Analyzer. This issue appears to be the result of design modifications implemented by Engineering Design Change (EDCR) #80-06, the Comsip Installation, and EDCR #86-30, "Bendix H2 Analyzer Relocation and Material Modification."

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6) Numerous instrument cables (approximately 100) in the cable vault were found to be routed l

I in the wrong cable tray section. Channel "A" cables were found routed in the channel "D" cable tray section, channel "B" cables were found routed in the "C" section, channel "C" i

cables were found routed in the "B" section, and channel "D" cables were found in the "A" section. Apparently the instrument tray was originally loaded with redundant instrument channel cables separated by vertical barriers. At some point in the past, the tray labeling designation was reversed. As a result, cablem were loaded in the mirror-image tray sections.

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7) Numerous cables of different separated trains or channels either touch or do not meet I

separation criteria based on inadequate cable tray configurations at transition points. As a result of plant walkdowns, it was determined that separation requirements are not l

maintained at transition points such as tray to riser intersection, tray to tray intersections, tray to sleeve intersections, tray to conduit intersections, and tray "T" intersections. At these transition points, cables of one separated train or channel either touch, mingle, or do not meet minimum air separation criteria with redundant train cables. This condition was noted to exist throughout numerous plant systems.

8) LPSI flow transmitter cables were found routed in the same sleeve as the control circuit cables for the LPSI stop valves. Instrument cables for Flow Transmitters FT-312,322, and 332 were routed in the same sleeve as the control circuits for the LPSI Header Stop Valves, LSI-M-11, LSI-M-21, and LSI-M-31.

NaC FORM 366A M-95) l v.

NRC.FoSM 3664 U.S. NUCLEAR REGULATORY COMMISSloN I

UCENSEE EVENT REPORT EER)

TEXT CONTINUATION FACILITY NAME (1)

DOCKET LER NUMBER (6)

PAGE (3)

YEA SEQUENTIAL REVISI f

Maine Yankee Atomic Power Company 50-309 4

OF 5

l 97 -- 01 00 l

TEKT (If more space is required, use additional copies of NRC Form 366A) (11}

SAFETY SIGNIFICANCE

The safety significance of each specific event, taken individually, is considered low. The i

equipment mentioned in paragraphs 1 through 8 has been demonstrated over the years to perform their intended functions. However, the cables associated with the equipment did not -

i meet cable separation criteria, and, as a consequence, contributed to an increase in l

susceptibility to single / common mode failure. The functionality of the systems involved was-not impacted.

. CAUSAL FACTORS:

The root cause investigation for cable separation issues identified a number of causal factors.

These causal factors are currently being assessed and evaluated by Maine Yankee management for input in developing long term corrective actions. The stated causal factors documented in Plant Root Cause Evaluation #214 are:

a

1) Ambiguous and conflicting cable separation criteria contributed to the cable separation deficiencies which have been identified.

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2) Plant electrical drawings (FEs) contain inaccurate information.

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3) Train affiliation labeling for cables and cable trays is less than adequate.

4) Cable separation training for engineers and craft personnel is less than adequate.

5).There is a lack of clear, specific criteria to evaluate current plant configuration or prepare plant modifications.

6) Design Basis information regarding cable separation is fragmented and unclear resulting in inconsistent application during implementation of the Engineering Design Change process.

7) The Engineering Design Change process, as implemented, lacks performance based self-j assessment to provide adequate information regarding cable separation deficiencies for

.j effective corrective action.

8) Engineering human resources are not effectively managed to support the inclusion of cable j

separation criteria in the implementation of the design change process.

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9) Inconsistent and frequently changing engineering goals and priorities foster decreased sensitivity to important issues such as cable separation.

10) The root cause analysis process focussed on self-disclosing, consequential problems and events.

11) The organization practice' too high a threshold for initiating formal root cause evaluations d

12) A climate of isolation f,nd self-reliance limited appreciation and application of industry developments.

NbQMI 36'6,A U.S. NUCLEAR REGULATORY COMMISSION (4-95)

LICENSEE EVENT REPORT (LER) i TEXT CONTINUATION 5

FACILITY NAME (1)

DOCKET LER NUMBER (6)

PAGE (3)

YEA SEQUENTIAL REVISI Maine Yankee Atomic Power Company 50-309 5

OF 5

97 -- 01 00 3

TEXT (if more space is required, use additional copies of NRC Form 366A) (11}

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13) An attitude prevailed that problems should be bounded and the scope of corrective actions minimized.

14) Problem identification and root cause analysis procedures did not require systematic root i

i cause analysis methods.

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CORRECTIVE ACTIONS

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The cable discrepancies. discovered during Maine Yankee's cable separation review have been, i

1 or are in the process of being corrected or addressed. Some of the cable discrepancies identified have been corrected, while others have not yet been fully evaluated for potential corrective actions or resolution at this time. Cable separation design and walkdown teams are in the process of identifying further corrective actions or engineering justification for identified discrepancies.

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l The long term corrective actions developed to address the recommendations identified in formal ruot cause evaluation #214, " Root Cause Investigation of Cable Separation Problems at Maine Yankee Atomic Power Company", are currently bein0 assessed and evaluated by Plant i

l Management. Investigation efforts for cable separation concerns will continue at Maine Yankee. Identified issues will be discussed in response to the requirements of Confirmatory I

l Action Letter 1-96-015, dated 12/18/96, and Supplement 1 dated 1/30/97.

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PREVIOUS SIMILAR EVENTS

i The following Licensee Event Reports describe similar cable separation events:

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1)

LER 96-038, Cable Separation 2)

LER 96-034, Bendix/Comsip Cable Separation 3'

3)

LER 94-005, Reg Guide 1.97 Containment Hydrogen Monitoring Instrumentaiton Outside j

Design Basis.

4)

LER 91-004, EFW Wiring Separation j.

5). LER 90-009, Engineered Safeguards Feature Light Box Design Deficiency 6

4 4

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