ML17325B522

LER 99-001-00:on 960610,degraded Component Cooling Water Flow to Containment Main Steam Line Penetrations,Identified on 990226.Caused by Inadequate Understanding of Design Basis.Additional Investigations Ongoing

ML17325B522
Person / Time
Site:	Cook
Issue date:	03/29/1999
From:	Berry L INDIANA MICHIGAN POWER CO.
To:
Shared Package
ML17325B521	List: ML17325B519 ML17325B522
References
LER-99-001, LER-99-1, NUDOCS 9904090204
Download: ML17325B522 (1)

Text

NRC Forn 366 U.S. NUCLEAR REGULATORY COMMiSSION APPROVEO BY OMB No. 3160 0104 EXP(RES 06130I2001 (6-1998) fSTSIIATED BURDEN PER RESPONSE TO COMPLY WITH T)SS MANDATORY WfORMATIONCOLLECTION REOUESTI 50 0 HRS. REPORTED LESSONS LEARNED ARE WCORPORATED WTO THE LICENSING PROCESS JJIO FEO BACK TO eeUSTRY.

LICENSEE EYENT REPORT (LER) fORWARD COMMENTS REGA)CING BURDEN ESTIMATE TO THE SP'ORMATION ANO RECORDS MANAGEMENT BRANCH ITS F55). U.S. NUCLEAR REGIAATORY COMMISSION. WAS)eNGTON. DC 205554ool. At TO THE PAPERWORK RECUCTION PROJECT (M500101), CFFCE Of MANAGEMENT AND BUDGET. WASHINGTON. DC (See reverse for required number of 205OS digits/characters for each block)

FACILITYNAME (1) DOCKET NUMBER (2) PAGE (3)

Cook Nuclear Plant Unit 2 05000-316 1of1 TITLE (4)

Degraded Component Cooling Water Flow to Containment Main Steam Line Penetrations EVENT DATE (5) LER NUMBER (6) REPORT DATE (7) OTHER FACILITIES INVOLVED(8)

A ILI NAM MONTH DAY YEAR YEAR SEQUENTIAL NUMBER

'EVISIONNUMBER MONTH DAY YEAR Cook Plant Unit 1 05000-315 A ILI Y HAM K NUM 06 10 1996, 1999 001 00 03 29 1999 OPERATING THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR (): (Check one or more) (11)

MODE (9) 20.2201 (b) 20,2203(a)(2)(v} 50.73(a)(2)(i) 50.73(a}(2)(viii)

POWER 20.2203(a)(1) 20.2203(a)(3)(i) 50.73(a)(2)(ii) 50.73(a)(2)(x)

LEVEL (10) 100 73.71 20.2203(a)(2)(i) 20.2203(a)(3)(ii) 50.73(a)(2)(iii) 20.2203(a)(2)(ii) 20.2203(a)(4) 50.73(a)(2)(iv) OTHER 20.2203(a)(2)(iii) 50.36(c)(1 } 50.73(a)(2)(v)

Speorry in Aberrso( below 20.2203(a)(2)(iv) 50.36(c)(2) 50.73(a)(2)(vii) or n NRC Form 366A LICENSEE CONTACT FOR THIS LER (12)

TELEPHONE NUMBER (Inc@de Aree Code)

Lyle R. Berry, Regulatory Compliance Engineer (616) 465-5901 x2637 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)

PP,,

REPORTABLE d. REPORTABLE TO CAUSE SYSTEM COMPONENT MANUFACTURER TO EPIX S CAUSE SYSTEM COMPONENT MANUFACTURER EPIX SUPPLEMENTAL REPORT EXPECTED (14) EXPECTED MONTH DAY X YES SUBMISSION 06 25 1999 (If Yes, complete EXPECTED SUBMISSION DATE) NO DATE (15 Abstract (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines) (18)

On February 26, 1999, during an engineering review of the Unit 2 Component Cooling Water System (CCW), it was identified that power operation was permitted in June 1996 with degraded CCW flow to the coolers for containment penetrations 2-CPN-3 and 2-CPN-4. The main steam headers for steam generators 22 and 23 pass through these penetrations. Operating with the degraded CCW to these coolers may have resulted in excessive thermal stress on the penetration sleeves/liners.

The Updated Final Safety Analysis Report (UFSAR) credits the penetration coolers for maintaining the temperature of adjacent concrete less than 150 degrees F. At the time of the event, containment exterior surface concrete temperatures were measured at a maximum of 155 degrees F. Operability determinations performed at the time of the event, to justify continued operation with degraded CCW flow to the main steam line penetrations, have been re-evaluated and found to be inadequate. This event was reported via a 4'hour non-emergency Emergency Notification System (ENS) report on February 27, 1999, pursuant to the requirements of 10CFR50.72(b)(2)(i). This LER is being submitted pursuant to the requirements of 10CFR50.73(a)(2)(ii)(B) as an event or condition that resulted in the nuclear power plant being in a condition that was outside the design basis of the plant.

Initial investigations indicate that the cause for this event was an inadequate understanding of the design basis for the containment penetration coolers. Additional investigations to assess potential degradation to the concrete, liners and sleeves at these penetrations are ongoing. The results of those investigations, including identified root cause(s),

preventive actions and safety significance will be provided when completed.

9'T)04090c)04 '))903c)9 PDR ADOCIJL 050003i6 8 PDR