ML20113D285

Forwards Info Supporting Removal of safety-related Piping & Mechanical Supports from Overinsp Program,Per 841025 Meeting Request.Concurrence W/Proposal Requested

ML20113D285
Person / Time
Site:	Clinton
Issue date:	03/29/1985
From:	Hall D ILLINOIS POWER CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
U-0828, U-828, NUDOCS 8504150194
Download: ML20113D285 (10)

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U-0828 L37-8 5 ( 0 3-2 9) -L ILLINDIS POWER COMPANY 1A.120 CLINTON POWER STATION, P.O. BOX 678. CLINTON, ILLINOIS 61727 March 29, 1985

$0' l Mr. James G. Keppler Regional-Administrator -- j slj Region III d' U. S. Nuclear Regulatory Commission  ;

799-Rooseveit Road Glen Ellyn, Illinois 60137 h{!(igb' "

Subject:

Proposed changes in the Illinois Power (IP) .

Company Overinspection Program

References:

1. Letter C. E. Norelius to W. C. Gerstner of November 21, 1984, forwarding letter for USNRC Mee ting Report No. 50-461/84-37 (DRP)

2. Letter D. P. Hall to H. R. Denton/J. G.

Keppler of February 13, 1985, forwarding letter for "Results of Quality Programs for Construction of Clinton Power Station".

Dear Mr. Keppler:

On October 25, 1984, Illinois Power met with members of your staff in your offices in Glen Ellyn, Illinois to discuss proposed changes to the IP Overinspection Program. Specifically, it was proposed that piping and mechanical supports be removed from the scope of the Overinspection Program. This proposal was based upon information resulting from program implementation which verified the quality of the piping and mechanical supports at Clinton Power Station. Therefore, continuation of the Overinspection Program for these types of items was unnecessary.

During the course of the meeting IP was requested to provide information on three additional topics to the NRC staff in order for the staff to evaluate the IP proposal. The requested infor-cation is described in notes of the meeting which were forwarded to.IP by reference 1 and is as follows:

The Overinspection Program was designed to be continu-ing activity until turnover of structures, systems and components to IPs however, criteria was not defined for termination of (re] inspections by category. Open item (461/84-37-03).

There was no information provided that showed the safety significance of the problems identified to date gugg g3gi 'APR 11985 8l#

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P during the Overinspection Program of large and small bore piping and piping supports. Such information is necessary to draw conclusions as to the safety signifi-cance of terminating the program before completing the overinspection of all lots of large and small bore piping. Open Item (461/84-37-02).

The data on page 15 of Attachment 1 was not sufficient to determine the actual percentage of total work that had been completed in any area. Open item (461/84-37-01).

This letter forwards, by attachment, the information re-quested by the NRC in support of IP's conclusion that removal of safety related piping and mechanical supports from the Overinspection Program is warranted. Attachment 1 provides the criteria for termination of inspection by category (Commodity) in response to NRC open item 461/84-37-03. Attachment 2 provides information specifically on safety related piping and mechanical supports in response to open items 461/84-37-02 and 461/84-37-01.

Attachment 3 demonstrates that these items meet the criteria in Attachment 1. It is to be noted that Sargent & Lundy performed an overall evaluation of results of the Overinspection Program, which was provided to the NRC, under cover of reference 2, as Chapter V and appendix D of the report "Results of Quality Programs for the construction of Clinton Power Station". The information and data contained in Attachments 2 and 3 to this letter is taken from that report and is a refinement and expansion of the information presented to the NRC on October 25, 1984. Attachments 2 and 3 also account for revisions made to the data presented in the report subsequent to its issue.

Your review of the attachment and your concurrence with the picposal to remove safety related piping and mechanical supports from the Overinspection Program is requested, if further information or clarification of the information already presented is necessary for evaluation of this request, please contact us at your earliest conveniance.

Sincerely yours, D. . all Vice President ATTACHMENTS JEK/skt cc: Director, Office of I&E, US NRC, Washington, DC 20555 NRC Resident Office Illinois Department of Nuclear Safety

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ATTACHMENT 1 RESPONSE TO NRC OPEN ITEM' 461/84-37-03 I. NRC Request The Overinspection Program was designed to be a.

continuing activity until turnover of structures, systems and components to IPs however, criteria was not defined for termination of [re] inspections by category.

II. IP Response IP has established the following criteria for termination of reinspections by category (commodity). These are a combination of numerical, statistical and engineering evaluation criteria and provide a high degree of confidence in decisions regarding the scope of the Overinspection Program.

III. Criteria All of the following three criteria shall be satisfied before reinspection of a safety-related commodity under the Overinspection Program is terminated.

A. A sufficient number of reinspections have been conducted to provide high confidence that the results of reinspections are representative of overall quality for a specific' commodity. This criterion will be satisfied for a commodity if at least 10,000 attributes have been reinspected for the commodity or at least 5% of the total number of items within the commodity have been inspected.

B. In the aggregate, the reinspections for a commodity did not identify a significant number of nonconforming attributes. This criterion will be satisfied if the rate of conforming attributes is at least 95%.

C. The reinspections for a commodity did not identify any nonconformance which had safety-significance with generic implications. A safety-significant nonconformance is defined as a nonconformance which, were it to have

- 7 remained unidentified by the Overinspection Program, could have resulted in the loss of

. capability of structure, system, or component to perform its intended safety function.

This criterion will be satisfied by an engineering evaluation, similar to that performed for the "Results of Quality Program,s for Construction of Clinton Power Sta tion

ATTACHMENT 2 Response to NRC Open Item 461/84-37-02 and -01 I. Open Item 461/84-37-02 A. NRC Request There was no information provided that showed the safety significance of the problems identified to date during the Overinspection Program of large and small bore piping and piping supports. Such information is necessary to draw conclusions as to the safety significance of terminating the program before completing the overinspection of all lots of large and snall bore piping.

B. IP Response IP requested Sargent & Lundy (with input from General Electric as necessary for GE designed components) to evaluate each Nonconformance Report to determine whether any of the nonconformances identified by the Overinspection Program were safety significant.

In general, S&L evaluated each nonconformance by one of three methods. First, many nonconformances on their face have little or no impact on the integrity of an item. Nonconformances in this ca tegory , for example , typically include minor documentation errors and cosmetic defects such as those arc strikes which do not reduce base metal thickness. These nonconformances can be designat-ed as having no safety significance, with no need to conduct more detailed evaluations.

Second, there are many types of nonconformances which do not adversely affect the function of an item because of the inherent conservatism of the design for the item. Many of these nonconform-ances, such as minor cases of undercut and surface slag on welds, are readily identifiable from engineering experience and knowledge of the design without the need to conduct detaile.1 calculations.

Finally, any nonconformance not falling within one of the above two categories was subject to detail-ed engineering evaluations to determine whether the nonconformance adversely affected the capabil-ity of a structure, system, or component to perform its intended safety function.

l Although S&L evaluated each nonconformance identi-fied by the Overinspection Program to determine whether it was safety significant, it should be emphasized that most of the nonconforming items u -

have been reworked in accordance with applicabic design drawings and specifications and the remaind-er have been determined to be acceptable as they are. Consequently, the evaluations below were performed to determine the safety significance of the nonconformances assuming they had been left uncorrected.

1. Piping The Overinspection Program identified 667 noncon-forming attributes on piping. As is discussed below, none of these nonconforming attributes was determined to be safety significant.

The majority (396) of the nonconforming attributes involved minor damage to pipe walls. Damage to pressure-retaining components was evaluated by considering if the reduction in the wall thickness was acceptable considering the minimum allowable wall thickness. Arc strikes constituted almost all of this ty,e of damage and were determined to be acceptable aased on the minimum allowable wall rec uirements for piping. The gouges, scratches, anc, cuts in piping also were judged to be accept-able based on minimum allowable wall thickness requirements.

Ninety-nine welding nonconformances affecting piping were evaluated. About one-fourth of the nonconformances were determined to be localized cosmetic surface defects, such as concavity, porosity, and surface slag. For more severe welding problems involving overlaps, undercut, lack of fusion, and undersized welds, localized pipe stresses were examined to determine the adequacy of the weld under all loading conditions.

In no case was the applicable code allowable stresses exceeded. There were 55 installation nonconforming attributes identified. These items were mostly small installation tolerance nonconformances that were acceptable. One hundred three documentation and procedural nonconformances were examined which required only " paper" corrections that had no impact on the physical design.

2. Mechanical (Piping) Supports A total of 4,576 nonconforming attributes were identified by the Overinspection Program in piping supports. The largest number (2,049) of noncon-forming attributes identified were in the welding

area. The next most prevalent nonconforming attributes are in the area of arc strikes (1,299) and installation nonconformances (924) .

Velding nonconformances on pipe supports primarily involved undersized welds, overlap, undercut, and slag inclusion. When the nonconforming welds could not be determined to be acceptable by other means, the nonconforming welds were evaluated by comparing the actual stresses (imposed on the weld without taking credit for damaged areas) to maximum stresses allowed by design. This comparison verified that sufficient margin existed in the nonconforming weld and the remaining welds on the support to preclude failure of the support.

Over 28% of the nonconforming attributes involved arc strikes. The majority of the remaining damage was comprised of gouges, defects caused by grind-ing, and bent component items. Arc strikes and gouges were evaluated to determine the effect of the reduction in base metal on the support's design capacity. No sup) ort was found to have sufficient reduction in aase metal to cause any piping support to fail. None of the remaining damage was determined to be safety-significant.

Installation nonconformances on pipe supports involved loose or incomplete hardware installa-tion, incorrect adjustment of supports, lack of clearance or interference, and construction tolerance nonconformances. Each nonconforming condition was evaluated to determine if the nonconformance was of a type that would be specifically examined in subsequent preoperational testing. For example, inspections that specifi-cally check for hot and cold positions of adjust-able support components would ensure that proper construction tolerances and construction complete-ness are verified prior to operation. Consequent-ly, these nonconformances were not significant because they would not have been left unidentified and uncorrected if the Overinspection Program had not been performed. For supports which are not adjustable, such as rigid or welded supports, specific preoperational programs to inspect for proper installation and fitup do not exist (other than 79-14 walkdowns conducted on plaing and support systems). In these cases, tae nonconform-ing attributes were evaluated for their impact on the structural integrity of the support. In no case was a safety-significant condition found to exist.

m Documentation-related nonconformances accounted

! for less than 2% of pipe support nonconforming attributes and typically pertained to the lack of a welder ID or hardware ID tag. Since evaluations j determined that all identifications required for safety-related hardware were recoverable from other records, there were no safety-significant nonconformances in this group.

II. Open item 461/84-37-01 ,

A. NRC Request The data on page 15 of Attachment 1 was not sufficient to determine the actual percentage of

total work that had been completed in any area.

< B. IP Response Percentage complete and number of attributes '

reinspected for safety related piping and

' mechanical supports by both BA Field Verification and IP Overinspection are tabulated below. J l

Percent Inspected Attributes Inspected FV OI FV OI i

Large Bore Pipe 13 6 19,376 7,634 Small Bore Pipe 10 10 32,114 5,938 i

Mechanical Supports 23 8 178,435 63,690 p-

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ATTACHMENT 3 Criteria For Terminating Reinspection of Commodities Piping and Mechanical Supports The information presented in this attachment demonstrates that safety-related piping and mechanical supports meet or exceed the criteria presented in Attachment 1 to this letter for termination of reinspection of commodities under the Overinspection program.

Criterion A: At least 10,000 attributes have been inspected for a commodity or at least 5% of the total number of items within the commodity have been inspected.

As is demonstrated by the table presented in attachment 2 to this letter -(NRC Open Item 461/84-37-01) large bore piping, small bore piping and mechanical supports meets or exceeds this criterion.

Criterion B: The rate of conforming attributes is at least 95%.

The following tables demonstrate compliance with this criterion in several different ways: Table 3.1 provides conformance rates based on FV data only, Table 3.2 provides conformance rates based on OI data only and Table 3.3 provides a com)arison of conformance rates for old and new wor (. Data in table 3.3 on old and new work utilizes only FV data since this is the first level of reinspection and therefore is the most conservative.

Table 3.1 Field Verification Conformance Rates Attributes Nonconforming Conformance Commodities Inspected Attributes Rates (%)

Large Bore 19,376 330 98.3 Pip e Small Bore 32,114 298 99.1 Pipe Mechanical 1 178,435 4083 97.7 Supports

1. Includes anchor plates, expansion anchors and hangers.

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Table 3.2 Overinspection Conformance Rates Attributes Nonconforming Conformance Commodities Inspected Attributes Rates (%)

Large Bore 7,634 25 99.7 Pip e Small Bore 5 ,938 14 98.8 Pipe Mechanical 1 63,690 493 99.2 Supports

1. Includes anchor plates, expansion anchors and hangers.

Table 3.3 Field Verification Conformance Rates for Old and New Work Attributes Nonconformance Conformed Commoditics Work Ins pe cte d Attributes Rates (%)

Large Bore Old 4,612 49 98.9 Pipe New 14,764 281 98.1 Small Bore Old 7,094 53 99.3 Pipe New 25,020 245 99.0 Mechanical 1 Old 18,060 597 96.7 Supports New 160,375 3486 97.8

1. Includes anchor plates, expansion anchors and hangers.

Criterion C: The reinspections for a commodity did not identify any nonconformance which had safety significance with generic implications.

As is discussed in Attachment 2 to this letter (NRC Open Item 461/84-37-02), an engineering evaluation was conducted of all nonconformances identified in safety related piping and mechanical j support. No nonconformance identified had any 1 safety significance. l 1

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