IR 05000245/1980025
| ML19348A034 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 03/27/1981 |
| From: | Sanders W, Lester Tripp NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | |
| Shared Package | |
| ML19348A031 | List: |
| References | |
| 50-245-80-25, IEB-80-07, IEB-80-13, IEB-80-17, IEB-80-17-S4, IEB-80-7, NUDOCS 8105280292 | |
| Download: ML19348A034 (5) | |
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O tr-U.S. NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT
REGION I
Report No.
50-245/80-25 Docket No.
50-245 License No.
DPR-21 Priority Category C
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Licensee:
Northea'st Nuclear Energy Company P. O. Box 270 Hartford, Connecticut 06101 Facility Name:
Millstone Nuclear Power Station. Unit #1 Inspection at:
Waterford, Connecticut Inspection conducted: December 15-18, 1980; January 27-30'and March 3-6, 1981 Inspector: J.'9I Cr
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-~; - 4 W. F. Sanders, Reactor Inspector date signed Approved by:
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L. E. Tripp, Chief, Materials and Processes date signed Section, Engineering Inspection Branch
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Insoection Summary:
Inspections on December 15-18, 1980, January 27-30 and March 3-6, 1981 (Report No. 50-245/80-25)
Areas Inspected:
Routine inspection of the inservice inspection program '
and core spray sparger inspection per IE Bulletin 80-13, Examination of Jet Pump Beam Examination Per IE Bulletin 80-07 and inspection and repair of Isolation Condenser piping.
An inspection was also made on the Scram Discharge Volume header continuous monitor of water level by Ultra Sonic, IE Bulletin 80-17 Supplement 4.
The inspection involved 52 inspector-hours on site by one regional-based inspector.
Results: No items of noncompliance or deviations were identified.
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DETAILS 1.
Persons Contacted Northeast Utilities Service Comoany E. Mroczka, Station Services Superintendent
- R. Herbert, Superintendent, Unit 1
'E.
Farrell, Superintendent, Unit 2
- E. Debarbera, Generation Mechanical Engineer E. Georgian, Engineer J. Leason, ISI Coordinator
- R. Palmieri, Engineering Supervisor W. Romberg, Operations Supervisor S. Sikorski, NDE Level II
- K. Thomas, Plant Test Engineer 2.
General This inspection report describes the inspection activities for three (3)
inspections and is part of six (6) inspections performed by the Engineering Support Section of the Reactor Construction Branch.
The first three (3)
inspections, documented in Inspection Report 50-245/80-22, document the inspection results for the routine inspection of the inservice inspection program, Torus modifications, Core Spray Sparger inspection, feedwater sparger replacement, Core Spray Line replacement, CRD line modification, main steam line restraint and Isolation Condenser line examinations.
The second (2) set of inspections document the follow up inspection on the Isolation Condenser lines, Jet Pump Beam Supports, and Scram Discharge Header instrumentation to monitor water volume and is documented in this report.
3.
Isolation Condenser The problem was initially identified when a liquid penetrant examination was performed on the inside surface of the supply line of the isolation condenser.
This NDE technique was used as an alternate to volumetric
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examination due to these welds being encapsulated in a guard pipe and unacccessible from the outside.
This examination disclosed circumferential cracking on both sides of the weld in the heat affected zone (HAZ) which has been classified as Intergranular Stress Corrosion cracking.
In addition to this failure mode, transgranular cracking was also evident.
All accessible welds in the isolation condenser supply and return lines were inspected using ultrasonic testing techniques specifically developed for the detection of intergranular stress corrosion cracking (IGSCC).
In addition, welds on other service sensitive piping were reinspected using this technique to confirm and/or evaluate reflectors identified during the
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Inservice Inspection Program.
Defective sections of the systems were repaired or replaced in accordance with ASME Section III and Section XI of the ASME Boiler and pressure vessel code and NRC NUREG 0313, Revision-1.
The following sections of the isolati.:n condenser piping were replaced:
Supply piping at the isolation concenser, both nozzle safe ends-and
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piping up to and including the first elbow.
Supply piping from the reacter vessel nozzle safe end to the containment
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Supply piping from the containment penetration to the second isolation valve.
Return line segment, removed to internally inspect adjacent welds.
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Process pipe to flued head weld on the isolation condenser supply
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containment penetration was repaired.
This weld contained linear indications revealed by dye penetrant inspection which was subsequently removed by grinding 360 degrees around the weld. A weld metal overlay was deposited over the root of the weld and continued to the end of the penetration thus covering the ID of the flued head forging with low carbon weld metal.
An inspection was made of the material test certifications for the pipe and elbow material that was used for the replacement sections described in LER 80-19/1x-1 (update report).
GE Product Quality Certification, P. O. Box 205xC872, 12" Shd. 80 S.S.
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Pipe.
GE Spec B504P166A1G-K, Rev. 2, HT. No. 38268-1A Lot 086, SN 9-74582P.
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Chemical Analysis, Mechanical Tests, Heat Treatment, NDE Exe.nination
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Verifications for Radiography, Ultrasor
ASME Section III Division 1, code data report NMI, Rolled and Welded-
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Sa. 240 Plate T316.
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No items of noncompliance were identified.
4.
Jet Pump Beam Examination, IE Bulletin 80-07 An additional inspection was performed on the Jet Pump Beams which had been examined in compliance with IE Bulletin 80-07 and designated as an unresolved item pending further review by the licensee (80-22-01). This item remains open.
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This item was considered unresolved pending resolution of nine questionable beams that had similar ultra sonic responses to the five that were rejected and repiaced. An acceptable method of evaluating and resolving the nine questionable beams was based on dye penetrant examinations of the five rejected beams after removal, to correlate visual indications with the ultrasonic responses. After removal of the defective beams a survey revealed radiation levels of 100R on contact, which caused the inspection program to be modified by substituting visuti inspection using an underwater camera with the capability of resolving a line.001" wide.
This inspection was considered inconclusive due to the inability to position the camera for a direct view of the interest area.
The next approach used involved the use
- of a water laser under water to remove corrosion scale and possibly reduce the radiation level sufficiently to perform a direct surface or visual examination. Although th's reduced the radiation level to 300 MR/hr on contact in approximately 12" water, the visual examination had to be performed with a fibre optics borescope. This inspection was also considered incon-clusive.
The licensee's planned action includes the following:
Package the one block, which has been determined to be the most severely
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cracked and send to a hot lab for decontamination and flaw sizing.
The start up would not be contingent upon completing this work.
Operate in the present condition until next outage and replace at
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least the nine (9) questionable beams.
A program of monitoring the pressure differential to determine heam
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failure is described in an operating procedure SP 638.1-Revision 3,
" Jet Pump Check" dated May 7, 1980, which verifies that the recirculation loop flow correlates to recirculation pump speed and that the total core flow correlates to core power.
The individual jet pump diffusar
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to lower plenum differential pressure is recorded and its ratio to average differential pressure is plotted daily and recorded in the operations log and shift surveillance OPS 10.10.
The licensee considers these actions to be adequate to identify a defective jet onmp beam in a timely manner. Within.i.he scope of the inspection, no items of noncom-pliance or deviations were identified.
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5.
Core Spray Spargers, IE Bulletin 80-13 A visual inspection of the Core Spray Spargers and the segment of piping between the inlet nozzle and the vessel shroud was performed using a remute underwater TV camera made by Westinghouse. The camera used was demonstrated to be capable of resolving a line.001 wide. The demonstration for suitable
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resolution and the examinations were recorded on video tape and could be reviewed on a TV monitor.
The examination was very sensitive and the areas were sufficiently lighted to see any surface abrasions. All of the images
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of a linear nature were reexamined and subsequently resolved as non-relevant. The inspector considered the examination to be capable of identi-fying any cracking or problem areas and considered the examinations to comply with the action requirements of the bulletin.
No items of noncompliance were identified.
6.
Exit Interview The inspector met with licensee representatives (asterisked in paragraph 1)
at the conclusion of the inspection on March 6, 1981. The inspector summarized the purpose, scope and findings of the inspection as discussed herein.
The licensee representatives acknowledged the inspector's summarization.
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