ML20115C690

Core Shroud Reinspection Plan for Unit 1 B111R1 Outage Oct 1996

ML20115C690
Person / Time
Site:	Brunswick
Issue date:	06/30/1996
From:	CAROLINA POWER & LIGHT CO.
To:
Shared Package
ML20115C689	List: BSEP-96-0245, Provides Plans for Reinspection of BSEP Unit 1 Core Shroud, Per GL 94-03.Reinspection Planned for B111R1 Refueling Outage Scheduled to Begin 961005 ML20115C690
References
PROC-960630, NUDOCS 9607120131
Download: ML20115C690 (3)

Text

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i Core Shroud

Reinspection Plan j Unit 1 l .B111R1 Outage

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i October 1996  !

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Recommended byf I /Y[._Date: I/ 2 8/ 78 Approved by: Date: d'~~30 '94, 9607120131 960705 PDR ADOCK 05000325 P pop

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, Unit 1 B111R1 Outage October 1996 INSPECTION

SUMMARY

l The scope of reinspection for the Unit I core shroud is based on the results of previous inspections l performed on both Unit I and Unit 2, guidance on shroud inspections contained in NRC Generic l Letter 94-03, BWRVIP s:mments "Guidelinesfor Reinspection ofBWR Core Shrouds" and "BWR Core ShroudInspection and Evaluation Guidelines" and continuing developments in the industry.

The inspections of the Unit I core shroud performed during the B109R1 outage (1993) met the requirements of NRC Generic Letter 94-03 of inspecting accessible areas of the shroud circumferential welds. In addition, vertical welds and several attachments welds, and other parts of l the core support structure were examined during these inspections. Specific areas on several l circumferential welds were benchmarked, so that they could be re-examined to determine the extent I l

of crack growth. A reinspection of the shroud was performed during the B110R1 outage (1995) l focusing on three objectives: (1) re-examination of selected areas to determine crack growth, (2) examination of previously inaccessible areas by use of specialized tooling and (3) examination of a  !

number of the installed clamps to verify no inservice degradation has occurred.

l For the B111R1 shroud reinspection, CP&L has developed a prioritized/ ordered inspection scheme structured to provide suflicient data such that an assessment of the structural integrity and previous cycle crack growth can be determined (see Table 1). The reinspection plan focuses on three l objectives: (1) re-examination of selected areas to determine crack growth, (2) examination of a i sample ofthe installed clamps to verify no inservice degradation has occurred and (3) application of l improved inspection techniques for welds where surfaces were not accessible with previously used inspection equipment. Specifically, as a minimum, UT examinations will be performed on the accessible areas of welds H6a, H6b and H7 (listed as Priority 1 items in the enclosed Table 1); l selected previously inspected areas on weld H5 to assess crack growth (listed as a Priority 1 item in Table 1); and three repair clamps will be VT inspected (listed as a Priority 1 item in Table 1).

Additional inspections will be performed if measurements indicate that crack growth is greater than anticipated (listed as Priority 2 items in Table 1). Predictions from crack growth models indicate that little, if any, crack growth is expected. This is consistent with predictions and actual results from the previous Unit 2 inspection.

UT inspections will be conducted utilizing pulse echo technology. Equipment and procedures for UT, l and for any supplemental VT, will be qualified in accordance with the inspection guidelines of the BWRVIP. The NDE uncertainty will be determined in qualification testing by the inspection vendor.

These qualifications will follow the BWRVIP inspection guidelines.

] An engineering evaluation of the inspection results will be performed using the flaw evaIuation i guidance issued by the BWRVIP in " Core ShroudIn.spection and Evaluation Guidelines", or other alternative industry criteria.

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. . TABLE 1 BNP UNIT 1 CORE SIIROUD REINSPECTION - B111R1 Weld Scope Priority Comments 100% of

Accessible Non-safety related weld. Inspect for crack growth and UT 2c Bottom structural margins.

(Below Ring)

I12/113 none n/a n/a Welds repaired by addition of clamps in I993.

Additional inspections will be performed if measurements indicate that crack growth is greater than anticipated.

100 %

Optionally, ifIl6a, II6b and 117 are all good for multiple i14 ofAccessible UT 2b cycles then inspect to reset evaluation baseline period.

Area (Weld can be stmeturally quahfied until B112R1 using NDE data from B109R1 and criteria from GENE-523-l 13-0894.)

As-Required UT 1 Selected previously inspected areas on weld 115 to assess crack growth Additional inspections will be performed if measurements 115 indicate that crack growth is greater than anticipated.

100 % UT 2a Optionally, ifI16a, il6b and 117 are all good for multiple l ofAccessible cycles then inspect to reset evaluation baseline period.

Area (Weld can be structurally qualified until B112R1 using NDE data from B109RI and criteria from GENE-523-113-0894.) l

". Inspect 100% of accessible area to obtain data for II6a ofAccessible UT 1 structural assessment. l Area l

i 100 %

Inspect 100% of accessible area to obtain data for i16b ofAccessible UT 1 structural assessment.

l Area 1

100 %

Inspect 100% of accessible area to obtain data for 117 of Access.ble i UT 1 structural assessment. l Area BWRVIP to develop tooling. These areas will be inspected

! 118 none n/a n/c consistent with guidance provided by the BWRVIP in the future.

i i 119 none n/a n/a Inspected during B110R1 Support none n/a n/a BWRVIP developing inspection tools / techniques.

Legs VT-3 clamps & hardware for general appearance and Repair 3 VT 1 missing parts.

Clamps VT.I integrity of tack welds.

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