IR 05000336/1987004

Insp Rept 50-336/87-04 on 870203-06.No Violations Noted. Major Areas Inspected:Eddy Current Exam of Steam Generator Tubes,License Action on Previous Insp Findings & Review of Inservice Insp Data

ML20207T351
Person / Time
Site:	Millstone
Issue date:	03/09/1987
From:	Mcbrearty R, Strosnider J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
To:
Shared Package
ML20207T325	List: IR 05000336/1987004 ML20207T324
References
50-336-87-04, 50-336-87-4, NUDOCS 8703230469
Download: ML20207T351 (4)

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U.S. NUCLEAR REGULATORY COMMISSION

REGION I

Report N /87-04 Docket N License N DPR-65 Priority Category C Licensee: Northeast Nuclear Energy Company Facility Name: Millstone Nuclear Power Station, Unit 2 Inspection At: Waterford, Connecticut Inspection Conducted: February 3-6, 1987 Inspectors: 7 p . A. McBrearty, Reactor Engineer date Approved by: //'///7 da.R.Strosnider, Chief Section, EB, DRS date terials and Processes Inspection Summary: Inspection on February 3-6, 1987 (Inspection Report No. 50-336/87-04)

Areas Inspected: A routine, unannounced inspection was conducted by one regional based inspector of activities associated with eddy current examination of steam generator tubes, licensee action on previous inspection findings, and review of ISI dat Results: No violations were identifie PDR 870316 G

ADOCK 05000336 ppg

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Details Persons Contacted Northeast Nuclear Energy Company L.D.'Baird, ISI Coordinator

R.T. Blanchard, ISI Coordinator

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F.R. Dacimo, Engineering Supervisor

8. Duffy, Assistant Engineering Supervisor

J. S. Keenan, Unit 2 Superintendent W. Rose, QA Enginee Combustion Engineering R. Maurer, ET Level III U. S. Nuclear Regulatory Commission

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'* T. A. Rebelowski, Senior. Resident Inspector

Indicates these present at the exit meetin . Licensee Action on Previous Inspection Findings (0 pen) UNR (336/86-24-04): Change T.S. to reflect plugging limit for sleeved steam generator tubes.~ The licensee has in its review process a proposed T.S. change which addresses the subject plugging limit. During this 1986 refueling outage a 20% plugging limit was used. Analysis has shown that sleeved tubes need not be plugged with less than 40% through wall flaws, and the 40% limit will be incorporated in the proposed The item will remain open pending completion of the licensee's action on the matte . Review of Inservice Inspection (ISI) Data The inspector reviewed selected ISI data representing ultrasonic, magnetic particle and liquid penetrant examinations to ascertain that the data were complete and that ASME code and regulatory requirements were met. Data associated with the following were included in the inspector's review:

Safety injection system weld BSI-C-3024 (UT)

SG-1 Cold leg to pump 1A weld P-3-C-3 (UT, MT)

SG-2 hot leg to RPV weld P-10-C-3 (UT, MT)

Loop 1 hot leg drain weld BPD-C-1015 (PT)

Loop 1 cold leg drain weld BPD-C-1025 (PT)

Safety injection system valve SI-237 (PT)

Shutdown Cooling "B" heat exchanger studs (5) (UT)

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, The. inspector reviewed ' records showing that penetrant indications were removed,-~te-examinations were performed and the related items were dispositioned based on the re-examination results. Ultrasonic examination results showing recordable indications were plotted, evaluated and'

dispositioned in accordance with applicable code requirement The "B" heat exchanger stud' examinations.were deferred from the last l outage,1985, of the first 10 year inspection interval and were done in f accordance with the ASME Code, 1974 Edition through Summer 1975 Addenda, the governing code for the interval. The performance of the stud exam-inations completed the category C-D requirements for the first 10 yea ' interva The inspector found that examination results were reviewed by the licensee

! and evaluations and dispositions were properly-documente No violations were identifie . Steam Generator Examination Activities After returning to power operation subsequent to the 1986 refueling outage-the licensee detected leakage within acceptable limits from steam generator

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1(SG-1). Eddy current examination-data were reviewed in an effort =by the L licensee to identify the leak location. The review identified a defective i

tube that was not plugged in SG-1 and this prompted the licensee to shutdown the plant. .The defect which.prompte_d the shutdown was found in cold ~ leg tube, line 136, row 42, about 3 inches above the tubesheet. ~A hydrostatic test which was performed during the' shutdown identified that SG-1 hot leg tube, line 24, row 19 was leaking within 2 inches of the tubesheet. Subsequent to detecting the leaking tube a review of previous eddy current data for the tube revealed a 31% through wall flaw at the leak lecatio Further licensee action is as follows:

SG-1

Examination of the defective portion of the leaking tube using specialized equipment which is capable of identifying the circumferential extent of the defect. The technique is quite time consuming and was used only on the leaking tub Results of the examination showed a 220* circumferential1y oriented defect with the 100% through-wall portion covering 40% of the tube circumferenc *

The leaking tube was plugge *

The previously unidentified defective tube, line 136, row 42 was plugge *

Because of problems experienced at tubes adjacent to tie rods, the licensee plugged 25 additional tubes near tie rods during the current outag .. .

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SG-2

Defective tube, line 48, row 94 was plugged. The defect was detected on the hot leg side at the top of the tubesheet during a review of eddy current tapes from the 1986 outag *

Additional tubes (12) near tie rods were plugge In addition to the above, data were reviewed which wereLoriginally analyzed by the individual responsible for the analysis of tube,'line 136, row 42 to determine whether other examples existed regarding defective tubes that_were not identified by the individual. The review performed by a Combustion Engineering Level III analyst identified 36 additional tubes (29 SG-1 tubes and >SG-2 tubes) which the licensee plans to remove from service by plugging. The licensee also has elected to stabilize (by staking) and plug five tubes surrounding the leaking SG-1 tube. No other tubes were stabilized during this outag No violations were identifie . Exit Meeting The inspector met with licensee representatives (denoted in paragraph 1)

at the conclusion of the inspection on February 6, 1987. The inspector summarized the purpose and the scope of the inspection and the finding At no time during this inspection, was written material provided by the inspector to the licensee.

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