ML18054A947

Forwards Palisades Nuclear Plant 1989 MIZ-18 Eddy Current Sys Qualification, Per 890731 Commitment

ML18054A947
Person / Time
Site:	Palisades
Issue date:	08/30/1989
From:	Frisch R CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML18054A948	List: ML18054A947 ML18054A949
References
TAC-69344, NUDOCS 8909060069
Download: ML18054A947 (5)

Text

I c-ansumers Power l'DWERINli MIC.HlliAN'S l'ROliRESS General Offices: 1945 West Parnell Road, Jackson,' Ml 49201 * (517) 788-0550 August 30, 1989 Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 DOCKET 50-255 - LICENSE DPR PALISADES PLANT -

MIZ-18 QUALIFICATION STATU~ UPDA~E (TAC NO. 69344)

By letter dated July 31, 1989, Consumers Power Company committed to provide the NRC with the results to date and status of the Miz-18 qualification project. Since this submittal, Consumers Power Company has completed a large portion of the statistical analysis necessary to assess the capabilities of the 580 bobbin, 540 bobbin, 4C4F, 8Xl and MRPC probes. Table 1 provides the status of this work for each technique and defect type.

Statistical analysis has been completed for those techniques and defect types that are of most importance to the eddy current inspection planned for the October 1989 outage. Statistical analysis that has not been completed will be performed as time permits prior to or following the October inspection.

Statistical analysis which is deemed unnecessary based on the initial results will not be performed. Table 1 also provides a summary of these conclusions.

Enclosed is the Miz-18 Eddy Current System Qualification Report which contains a complete description of the qualification process and all of the results known to date. Table 2 provides a summary of the results obtained for each completed section.

Conclusions based on the qualification project are as follows:

1. The 580 bobbin probe characterizes wastage type degradation more accurately and consistently than the 540 bobbin probe. Both techniques have a tendency to overcall the depth of the defect by approximately 3%.

The qualification results for the 580 and 540 bobbin probes in conjunction with the Miz-18 tester are superior to that of the Miz-12 tester in both dented and nondented regions.

2. The 580 bobbin probe has a tendency to undercall the average IGA front by approximately 4%, however, it provides much more consistent characteriza-tion than either the 4C4F or 8Xl pancake probes. Taking both the mean and (

OC0889-0178AA-NL04 ID\

A CMS NERGY COMPANY

Palisades Plant Nuciear Regulatory Commission Miz-18 Qualification Status Update August 30, 19"89

• 2 standard deviation into account the 580 bobbin probe provides the best overall characterization of IGA. None of the three probes accurately size the IGA maximum penetration depth.

3. The 8Xl pancake probe and the MRPC have crack detection capabilities which are superior to the 4C4F pancake probe. Both the 8Xl and MRPC are able to consistently detect cracks at 35% through wall versus 50% for the 4C4F.

4. Neither the 8Xl pancake probe, the MRPC or the 4C4F pancake probe are capable of consistently sizing the depth of cracks.

The results of this investigation will be employed in future eddy current inspections of the current Palisades steam generators. As was committed in our July 31, 1989 submittal, Consumers Power Company will inform the NRC of the final eddy current inspection scope, including which specific techniques will be used, prior to the start of the October 1989 outage.

r;<t\lfk~~cL Ralph R Frisch Senior Licensing Analyst CC Administrator, Region III, USNRC NRC Resident Inspector - Palisades Attachments OC0889-0178AA-NL04

TABLE 1 MIZ-18 QUALIFICATION STATUS THROUGH AUGUST 21, 1989 Defect

.Technique Type Statistical Analysis Status 580 Bobbin Wastage Complete IGA Complete Crack Not complete (completion unnecessary) 540 Bobbin Wastage Complete IGA Not complete (completion intended)

Crack Not complete (completion unnecessary) 4C4F Wastage Not complete (completion unnecessary)

IGA Complete Crack Complete 8Xl Wastage Not complete (completion unnecessary)

IGA Complete Crack Complete MRPC Wastage Not complete (completion intended)

IGA Not complete (completion intended)

Crack Complete Axial Wound Wastage Not complete (completion unnecessary)

Rotational IGA Not complete (completion unnecessary)

Crack Not complete (completion unnecessary)

Sleeve Not complete (completion intended)

OC0889-0178AA-NL04 J

TABLE 2 STATISTICAL ANALYSIS

SUMMARY

(Based on All Data Points Bounded by the Given Defect Depth and Dent Size)

Dent Defect Detection Defect Size Standard Technique Type Limit (%) Depth (%) it!!hl Mean Deviation 580 Bobbin Wastage 20 > 20 < 8 2.95 8.03 540 Bobbin Wastage 20 > 20 < 8 3.27 8.55 580 Bobbin IGA - 30 > 30 < 10 -4.18 8.39 Average Front

!GA - 30 > 30 < 10 -25.19 15.19 Maximum Penetration 8Xl Pancake IGA - 30 > 30 < 10 -2.62 18.78 Average Front IGA - 30 > 30 < 10 -23.64 22.25 Maximum Penetration 4C4F Pancake IGA - 30-38 > 30 < 10 -0.52 14.67 Average Front IGA - 30-38 > 30 < 10 -22.70 18.81 Maximum Penetration 8Xl Pancake Crack 35 > 52 < 10 0.51 12.54 4C4F Pancake Crack 50 > 52 < 10 5.73 12.53 MRPC Crack 35 > 52 < 10 -11.30 11.89 MI0889-01691AAA-TC01

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ATTACHMENT Consumers Power Company Palisades Plant Docket 50-255 MIZ-18 EDDY CURRENT SYSTEM QUALIFICATION REPORT August 30, 1989 334 Pages OC0889-0178AA-NL04