05000315/LER-1998-017, :on 980327,debris Was Found in Sample Ice from Ice Condenser Sys.Caused by Poor Work Practices.Ice Condenser Has Been Completely Thawed & Inspection,Repair & Refurbishment Activities Have Begun

:on 980327,debris Was Found in Sample Ice from Ice Condenser Sys.Caused by Poor Work Practices.Ice Condenser Has Been Completely Thawed & Inspection,Repair & Refurbishment Activities Have Begun

ML17334B808
Person / Time
Site:	Cook
Issue date:	07/01/1998
From:	Sampson J, Schoepf P AMERICAN ELECTRIC POWER CO., INC., INDIANA MICHIGAN POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-98-017, LER-98-17, NUDOCS 9807080027
Download: ML17334B808 (9)

LER-1998-017, on 980327,debris Was Found in Sample Ice from Ice Condenser Sys.Caused by Poor Work Practices.Ice Condenser Has Been Completely Thawed & Inspection,Repair & Refurbishment Activities Have Begun

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(i) 10 CFR 50.73(a)(2)(viii) 10 CFR 50.73(a)(2)(iii) 10 CFR 50.73(a)(2)(iv), System Actuation 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(x) 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded
3151998017R00 - NRC Website

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CATEGORY 1

.I REGULATORY INFORMATION DISTRIBUTION STEM (RIDS)

ACCESSION NBR:9807080027 DOC.DATE:'98/07/01 NOTARIZED: NO DOCKET FACXL:50-315 Donald C.

Cook Nuclear Power Plant, Unit 1, Indiana M

05000315 AYAH.NAME AUTHOR AFFILIATION SCHOEPF,P.

Indiana Michigan Power Co'.

SAMPSON, J.R.

Indiana Michigan Power Co.

RECIP.NAME RECIPIENT AFFILIATION

SUBJECT:

LER 98-017-01:on 980327,debris was found in sample ice from ice condenser sys.Caused by poor work practices.Ice condenser has been completely thawed

& inspection, repair tc refurbishment activities have begun.W/980701 ltr.

DISTRIBCTION CODE: IE22T COPIES RECEIVED:LTR 1

ENCL J SIZE:

TITLE: 50.73/50.9 Licensee Event Report (LER), Incident Rpt, etc.

NOTES:

RECIPIENT ID CODE/NAME PD3-3 PD INTERNAL: AEOD/SPD/RAB NRR/DRCH/HICB NRR/DRCH/HQMB NRR/DSSA/SPLB RES/DET/EIB EXTERNAL: L ST LOBBY WARD NOAC POORE,W.,

NRC PDR COPXES LTTR ENCL 1

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1 RECIPIENT ID CODE/NAME STANG,J AEOD/SPD/RRAB NRR/DE/ECGB NRR/DE/EMEB NRR/DRCH/HOHB NRR/DRPM/PECB NRR/DSSA/SRXB RGN3 FILE 01 LITCO BRYCE,J H NOAC QUEENER,DS NUDOCS FULL TXT COPIES LTTR ENCL 1

1 1

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N NOTE TO ALL "RIDS" RECIPIENTS:

PLEASE HELP US TO REDUCE WASTE. TO HAVE YOUR NAME OR ORGANIZATION REMOVED FROM DISTRIBUTION LISTS OR REDUCE THE NUMBER OF COPIES RECEIVED BY YOU OR YOUR ORGANIZATION, CONTACT THE DOCUMENT CONTROL DESK (DCD)

ON EXTENSION 415-2083 FULL TEXT CONVERSION REQUIRED TOTAL NUMBER OF COPIES REQUIRED: LTTR 23 ENCL 23

American Electric Pow~

Cook Nuclear Plant One Cook Place Bridgman, MI49106 6164655901 AMERICAN ELECTRIC POWER July 1, 1998 United States Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 Operating Licenses DPR-58 Docket No. 50-315 Document Control Manager:

'In accordance with the criteria established by 10 CFR 50.73 entitled Licensee Event

<<h fll ig i

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i<<d.'8-017-01 Sincereiy,

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J. R. Sampson Site Vice President lmbd Attachment C. J.

Paperiello (Acting), Region ill J. R.

Sampson P. A.

Barrett S. J.

Brewer R.

Whale D.

Hahn Records Center, INPO NRC Resident Inspector 9807080027 98070i PDR AGOG@ 05000$ i5 S

PDR

NRC Form 366

'I (4-95)

U.S. NUCLEAR REGULATORYCOMMISSION LICENSEE EVENT REPORT (LER)

(See reverse for required number of digits/characters for each block)

API'ROVEDSY OMB NO. M504)I04 EXPNIES OU$0III ESTNATEO BURDEN PER RESPONSE TO COMPLY WITH THIS MANDATORY INFORMATIONCOLLECTION REOUEST: 50.0 HRS. REPORTED lESSONS LEARNED ARE eCORPPORATEO UITO THE UCENSSIG PROCESS ANO FED SACK TO INDUSTRY. FORWARD COMMENTS REGARDING BURDEN ESTSIATE TO THE UIFDRMATIDNAND REcoRDs MANAGEMENTsRANcH IT4 FSS). U.s. NUclEAR REGULATORY COMMISSION. WASHNGTON.

OC

$05550001, AND 1'0 THE PAPERWORK REDUCTION PROJECT ($150010I). OFFICE OF MANAGEMENTAND BUDGET.WASHNGTOILOC $050$

FACILITYNAME(I)

TITLE(4)

Cook Nuclear Plant Unit 1 DOCKET NUMBER(3) 50-315 PAGE (3) 1 of5 Debris Recovered from Ice Condenser Represents Unanalyzed Condition EVENT DATE (5)

LER NUMBER (6)

REPORT DATE (7)

OTHER FACILITIESINVOLVED(8)

MONTH 03 DAY 27 YEAR YEAR 98 98 SEQUENTIAL NUMBER 017 REVISION NUMBER 01 MONTH DAY YEAR 07 01 98 A ILI NAM Cook - Unit 2 A ILI NAM NUMB 50-316 D

CKET NUMBER OPERATING MODE (9) 50.73(a)(2)(i) 20.2203(a)(2)(v) 20.2201 (b)

THIS REPORT IS SUBMITTEDPURSUANT TO THE REQUIREMENTS OF 10 CFR (I: (Check one or more) (11) 50.73(a)(2)(viii)

POWER LEVEL(10) 20.2203(a)(1) 20.2203(a)(2)(i) 20.2203(a)(2)(U) 20,2203(a) (2)(III) 20.2203(a)(2)(iv) 20.2203(a)(3)(i) 20.2203(a)(3)(ti) 20.2203(a)(4) 50.36(c)(1) 50.36(c)(2)

LICENSEE CONTACT FOR THIS LER (12) 5o.73(a)(2)(ii) 50.73(a)(2)(iii) 50.73(a)(2)(iv) 50.73(a)(2)(v) 50.73(a)(2)(vii) 50.73(a)(2)(x)

OTHER 73.71 Yn Aberraot below or n NRC Form 366A NAME TELEPHONE NUMBER(Indude Area Code)

Mr. Paul Schoepf, Safety Related Mechanical Engineering Superintendent 616/465-5901, x2408 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)

CAUSE

SYSTEM COMPONENT MANUFACTURER REPORTABLE TO NPRDS

CAUSE

SYSTEM COMPONENT MANUFACTURER REPORTABLE TO NPRDS SUPPLEMENTAL REPORT EXPECTED (14)

YES (IfYes, complete EXPECTED SUBMISSION DATE).

X NO EXPECTED SUBMISSION DATE (15)

N H OAY Abstract (Limitto 1400 spaces, I.e., approximately 15 single-spaced typewritten lines) (16)

On March 27, 1998, debris was found in a sample of ice from the Ice Condenser System. The Unit 1 Ice Condenser was then completely thawed and three 55-gallon drums of debris were collected. The debris could have blocked flow through Ice Condenser floor drains and Containment Recirculation Sump screens, which represents an unanalyzed condition. An ENS notification was made on March 27, 1998, in accordance with 10CFR50.72(b)(2)(i) for an unanalyzed condition, and this LER is submitted in accordance with 10CFR50.73(a)(2)(ii)(A) for an unanalyzed condition.

The root cause of debris in the Ice Condenser was determined to be poor work practices, with contributing causes of written communications and supervisory methods. To insure all debris is removed, both units'ce Condensers will be carefully inspected following the complete thaw of ice. The Ice Condenser worker training program willbe overhauled and video inspections of ice baskets willbe performed, Ice Condenser Foreign Material Exclusion and task standards will be revised, and oversight responsibility of Ice Condenser work willbe transferred from Engineering to the Maintenance Department to access a larger staff skilled in production supervision.

The quantity of debris is negligible compared to the mass of ice in the Ice Condenser, and is not a threat to Ice Condenser performance. However, taken in aggregate, the additional debris from the Ice Condenser would have exacerbated the fibrous material condition described in LER 50-315/97-024, further degrading the ability of the Containment Recirculation Sump to perform its function.

NRC FORM 366 (4-95)6 (4-95)

LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION U.S. NUCLEAR REGULATORY COMMISSION, FACILITYNAME(1)

Cook Nuclear Plant Unit 1 DOCKET NUMBER(2) 50-315 YEAR 98 LER NUMBER (6)

SEQUENTIAl NUMBER 017 REVISION NUMBER 01 PAGE (3) 2of5 TEXT (Ifmore spaceis required, use edditionel copies ofNRC Form (366A) (17)

CONDITIONS PRIOR TO EVENT

Unit 1 was in Mode 5, Cold Shutdown Unit 2 was in Mode 5, Cold Shutdown

DESCRIPTION OF EVENT

The primary function of the safety-related Ice Condenser system is the absorption of thermal energy released abruptly in the event of a Loss of Coolant Accident (LOCA) or Main Steam Line break (MSLB) inside Containment, to limitthe initial peak Containment pressure. The system consists of a completely enclosed annular compartment located around approximately 300 degrees of the perimeter of the Containment. The main part of the Ice Condenser is a mass of sodium tetraborate ice stored inside the compartment. The sodium tetraborate solution produced by the melting ice absorbs and retains iodine released during the accident and serves as a heat transfer medium and neutron poison for reactivity control following the postulated design basis incident (LOCA). The total ice mass provides sufficient heat removal capability to condense the steam released during a LOCAor a MSLB event. The Ice Condenser plays no role in the normal operation of the plant.

Accomplishment of the function of the Ice Condenser system depends upon the quantity and distribution of the ice mass within the Ice Condenser. The ice mass is contained within an array of 1944 ice baskets. Eighty-one ice baskets, arranged in a 9 by 9 grid, are located in each of the 24 bays of the Ice Condenser. The ice baskets are 48 feet tall with an approximate diameter of 12 inches. The vertical portion of the basket is substantially open to accommodate heat transfer.

The borated water from the melted ice passes through the Ice Condenser floor drains and into the Containment Recirculation Sump.

The Containment Recirculation Sump is located in the basement of the lower Containment, and collects water from the Reactor Coolant System, the Containment Spray System, and the Ice Condenser for the Emergency Core Cooling System (ECCS) pumps during the recirculation phase following a LOCA. The Recirculation Sump screen prevents debris from flowing into the ECCS pump suctions during recirculation. The vertical screen and an outer trash rack are designed to prevent missiles and other debris from entering the ECCS pump suction piping.

Inspection of a filter in the system used to melt ice obtained from a sample of 110 Unit 1 and five Unit 2 ice baskets revealed the presence of debris. The nature and volu'me of debris found from both units was such that the potential existed to block flow through the Ice Condenser floor drains and Containment Recirculation Sump screens.

Flow blockage of the Containment sump screens would reduce the amount of borated water available for long term reactor core and Containment cooling, and represents an unanalyzed condition.

The decision was made to completely thaw both units'ce Condensers to address a variety of issues, including the existence of debris in the ice bed. The thaw of the Unit 1 Ice Condenser was completed in late May, 1998, and thaw of the Unit 2 Ice Condenser is scheduled to begin in July, 1998.

I The type of debris found in the Unit 1 Ice Condenser includes a variety of materials, such as:

tape (including complete rolls) coat plastic banding ice basket coupling screws and screw heads ice basket cruciforms rope gloves plastic wrap cloth nuts 8 bolts wire rags(4-95)

LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION U.S. NUCLEAR REGULATORY COMMISSION FACILITYNAME(1)

Cook Nuclear Plant Unit 1 DOCKET NUMBER(2) 50-315 YEAR LER NUMBER (6)

SEQUENTIAL NUMBER REVISION NUMBER PAGE (3) 3of5 98 017 01 TEXT (ifmore space is required, use additional copies ofNRC Form (366A) (17)

DESCRIPTION OF EVENT (cont'd) flashlights and batteries plastic tubes from tube lights wood paper small hand tools (such as wrenches) larger tools (such as pneumatic vibrators, weigh rigs, and metal bars used to maintain the ice bed).

While some minor amounts of debris are still being removed from the Unit 1 Ice Condenser, an estimate of the volume of material was three 55-gallon drums, based on visual surveys of removed material and walk downs of the Ice Condenser.

It was further estimated that five cubic feet of material removed from the Unit 1 Ice Condenser was considered transportable to the Containment Recirculation Sump (items such as paper, tape, cloth, rope, etc). However, it should be noted that most of the material considered transportable to the Containment Recirculation Sump remained in the ice baskets following the Unit 1 Ice Condenser thaw.

The Unit 2 Ice Condenser thaw has not started, but the types and quantities of debris are expected to be similar due to

. similar maintenance practices for the two Ice Condensers.

CAUSE OF EVENT

The cause of the debris in the Ice Condenser was poor work practices. Foreign material entered the ice bed as a result of poor work practices during plant construction, initial ice load, or during subsequent surveillance and maintenance activities, which did not preclude entry of material into the ice bed.

A contributing cause was poor written communications. Strict standards and procedures did not exist to control foreign material during initial ice load or during subsequent maintenance activities on the ice bed.

Another contributing cause was poor supervisory methods resulting in ineffective contractor control. Contract personnel have historically performed most work inside the Ice Condenser under the supervision of personnel in the Engineering department. Training for contract ice crew personnel stressed the importance of Ice Condenser cleanliness, and there is evidence that workers understood this, however supervisory oversight was not effective in converting this knowledge into adequate worker performance.

ANALYSISOF EVENT On March 27, 1998, an ENS notification (EN 33975) was made in accordance with 10CFR50.72(b)(2)(i), for a condition found while the reactor was shutdown, which ifit had been found while the reactor was operating, could have resulted in the plant being in an unanalyzed condition. This LER is therefore submitted in accordance with 10CFR50.73(a)(2)(ii)(A), for an unanalyzed condition.

I The safety significance of debris in,the ice bed was considered in a 1984 Westinghouse report, which outlined the primary threats caused by debris. The significance can be summarized as, "any accumulation of debris is unacceptable ifit prevents the ice condenser system from operating at its minimum required capacity. This can happen ifdebris reduces the ice inventory below the minimum required, ifit prevents the proper flowof steam through the ice bed, or ifit unacceptably reduces the heat transfer from steam to the ice,...debris must not have an unacceptable impact on the operation of the emergency core cooling system and/or the Containment spray system."(4-95)

LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION U.s. NUCLEAR REGULATORY COMMISSION'ACILITY NAME(1)

Cook Nuclear Plant Unit 1 DOCKET NUMBER(2) 50-315 YEAR 98 LER NUMBER (6)

SEQUENTIAL NUMBER 017 REVISION NUMBER 01 PAGE (3) 4of5 TEXT (ifmote space is te quite d, use additional copies ofNRC Form (366A) (1 7)

ANALYSISOF EVENT (cont'd)

Following the melt of the Unit 1 ice, itwas confirmed that the quantity of debris in the ice was noteworthy, comprising an estimated volume of three 55-gallon drums, with an estimated 5 cubic feet of the debris being potentially transportable from the ice baskets to the Containment Recirculation Sump.

Although this quantity of material is noteworthy given plant foreign material standards, this quantity of material is negligible compared to the quantity of ice resident in the ice beds. Given the small volume and weight of the debris compared to the volume and weight of the ice, the existence of this material is not considered a significant threat to Ice Condenser thermal performance.

The quantity of material is significant, however, from the perspective of potential threats to Containment Recirculation Sump blockage. Post-melt surveys of the Unit 1 Ice Condenser indicated that most debris was resident in the ice bed, and fell to the bottom of the basket during melting. For debris in the ice bed to threaten the Recirculation Sump:

1. The blowdown forces due to an accident would have to force the debris to travel up through the ice baskets, through the upper deck grating, and over to and down the refueling cavity drains; or,

2. The debris would have to travel out of the sides or bottoms ofthe ice baskets (through the 1" mesh), through the floor drain grating (1.75 inch openings), and through 12 inch flapper valve drains to the lower Containment.

Although both paths are somewhat tortuous, and there are no models to study debris transport for this type of material, if the noted quantities of debris are present, some would likely transport to the Recirculation Sump, reducing the flow area through the Recirculation Sump screens.

A previous Licensee Event Report (LER) (LER 50-315/97-024-04), addressed degradation of the Containment Recirculation Sump due to fibrous material found in Containment, which could potentially have caused excessive blockage of the sump screen. The issue of Containment Recirculation Sump screen blockage discussed in LER 97-024-04 is relevant to this LER because, taken in aggregate, the additional debris from the Ice Condenser would have exacerbated the condition described in LER 97-024, further degrading the ability of the Recirculation Sump to perform its function.

I

CORRECTIVE ACTION

The Unit 1 Ice Condenser has been completely thawed, and inspection, repair, and refurbishment activities have begun.

The Unit 2 Ice Condenser thaw is scheduled and willalso be followed by a number of inspection, repair and refurbishment activities. The thaw of each Ice Condenser includes removal of debris from the ice baskets and flow passages.

A detailed inspection will be performed of each Ice Condenser bay for cleanliness prior to refilling ice baskets in that bay. Production

. of ice and reload of ice into each Ice Condenser willbe strictly controlled to ensure that foreign material is not introduced into the ice beds during refill.

I To improve work practices, the training program for personnel performing work in the Ice Condenser is being overhauled.

Training willprovide focused information to raise the sensitivity ofworkers to foreign material, and to inform workers of new strict controls for foreign material in the Ice Condensers.

Avideo inspection willbe performed of baskets emptied for maintenance, prior to basket refillwith ice, which willafford an opportunity to identify any foreign material remaining in baskets after emptying. Additionally, a final inspection of emptied baskets willbe performed by QC personnel just prior to refill, which willprovide a final check of ice basket cleanliness.(4-95)

LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION U.S. NUCLEAR REGULATORY COMMISSION FACILITYNAME(1)

Cook Nuclear Plant Unit 1 DOCKET NUMBER(2) 50-315 YEAR 98 LER NUMBER (6)

SEQUENTIAL NUMBER 017 REVISION NUMBER 01 PAGE (3) 5of5 TEXT (Ifmore space is required, use additional copies ofNRC Form (366A) (17)

CORRECTIVE ACTION (cont'd)

To improve written communications related to the Ice Condensers, standards for control of foreign material within the Ice Condensers are being revised to invoke strict controls to preclude the entry of foreign material into the ice bed.

To address poor supervisory methods, responsibility for oversight of Ice Condenser, production workers is being realigned from the Engineering department to the Maintenance department. The Maintenance department has more production supervisors with the skills necessary to provide thorough supervisory oversight to workers compared to the Engineering department. Therefore, this realignment of responsibilities is expected to result in improved worker performance in foreign material control.

FAILEDCOMPONENT IDENTIFICATION Not Applicable

PREVIOUS SIMILAREVENTS

LE R 50-315/97-024-04 t'

0