ML20072F309

Interim Deficiency Rept 82-10 Re Violation of Min Wall Thickness for safety-related Piping.Initially Reported on 821007.Sargent & Lundy Reviewing Piping Design.Piping Lines 1LP21A4 & 1LP21B4 Modified.Next Rept within 90 Days

ML20072F309
Person / Time
Site:	Clinton
Issue date:	06/17/1983
From:	Hall D ILLINOIS POWER CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
10CFR-050.55E, 10CFR-50.55E, 1605-L, 82-10, U-10063, NUDOCS 8306270334
Download: ML20072F309 (4)

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ILLIN0/S POWER COMPANY 1605-L jfj[I U-10063 CLINTON POWER STATION, P.O. BOX 678, CLINTON, ILLINOIS 61727 Docket No. 50-461 June 17, 1983 Mr. James G. Keppler Regional Administrator Region III U. S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137

Subject:

Deficiency 82-10 10CFR50.55(e)

Safety Related Piping Minimum Wall Thickness Violations

Dear Mr. Keppler:

On October 7, 1982, Illinois Power verbally notified Mr. P.

Pelke, NRC Region III of a potentially reportable deficiency per 10CFR50.55(e) concerning possible minimum wall thickness violations for safety related piping. This initial notification was followed by two (2) interim reports (letter U-10009, D. P.

Hall to J. G. Keppler dated November 12, 1982, and letter U-10027, D. P. Hall to J. G. Keppler dated February 10, 1983).

This letter presents an update of our investigation and status of corrective actions, and is submitted as an interim report on this reportable deficiency.

STATEMENT OF REPORTABLE DEFICIENCY Two (2) cases have been identified where piping with less than minimum allowable pipe wall thickness was installed in ASME Class 2 piping systems:

a.) In the Residual Heat Removal (RHR) system, line number 1RH03BB12, pipe of 0.375 inch (nominal) wall thickness was installed; design documents dictated the use of pipe of 0.843 inch (nominal, schedule 100) wall thickness.

b.) In the Low Pressure Core Spray (LP) system, line numbers lLP21A4 and lLP21B4, pipe of 0.237 inch (nominal, schedule 40) wall thickness was installed; design documents dictated the use of pipe of 0.337 inch (nominal, schedule 80) wall thickness.

This condition has been determined to be a significant deficiency in final design and construction and therefore is reportable under 10CFR50.55(e).

vc 8306270334 8306'17 JUN 2 01983 PDR ADOCK 05000461 S PDR

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. J..G. Kappler June 17, 1983 BACKGROUND / INVESTIGATION RESULTS As part of the preservice inspection program, certain welds were being ultrasonically examined for weld thickness by Baldwin Associates (Illinois Power Contractor). These examinations found

that the wall thickness of the pipe at several welds in the RHR

. system was less than required by applicable piping installation documentation. Nonconformance Report (NCR) 7618 was written to document this problem.. Evaluation of this NCR' determined that the measured wall thickness (0.305 inch) at the weld was not only less than specified in the installation documents (0.375 inch),

but the installation documents did not correspond to the design information (0.'406 inch) supplied by-Sargent & Lundy (CPS Archi-tect/ Engineer). Further investigation showed that the various

design documents supplied by Sargent & Lundy to the. Piping Fabricator (Southwest Fabricating and Welding) contained incon-sistencies. Conservative design information for this pipeline required a nominal wall thickness of 0.843 inch (Schedule 100).

Nonconformance Report 7833 was written to document this problem.

Investigation found that several errors led to this occur-rence. When the pipe was detailed and fabricated, the Sargent &

Lundy piping line list correctly specified schedule 100 (0.843 inch nominal wall thickness) for pipeline IRH03BB12. However,

.the associated Sargent & Lundy piping and instrument diagram and

! the single line piping drawing for this pipe erroneously l specified schedule 40 (0.406 inch nominal wall thickness). _The

-fabrication isometric drawing and spool piece details drawing produced by Southwest Fabricating and Welding erroneously specified standard wall thickness for this line (0.375 inch nominal). As a result, the pipe was fabricated and installed as

-standard wall pipe, in accordance with the incorrect isometric j and spool piece detail drawings.

In reviewing the. design history of this pipeline, it was determined that the original design was properly performed and all design. documents were consistent. However, in late 1978 and j early 1979, new loads adequacy evaluation had proceeded to the l , point that suppression pool swell-loads on the pipe required that

! pipe. wall thickness for certain lines be increased. This required wall thickness increase was not properly transferred to all affected design documents.

. Investigation of other piping affected by this external load has 'shown that one :(1) additional system, line numbers 1LP21A4 and'lLP21B4, has wall thickness problems. In this case, the L piping line list and P&ID specified schedule'80 (0.337 inch nominal wall thickness), but the piping drawing specified schedule 40 (0.237 inch nominal wall thickness), and the isometric drawing shows schedule 40. Schedule 40 pipe was subsequently installed. Nonconformance Report 8201 was written to; document this problem.

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J. G. Keppler June 17, 1983 Similar cases of this problem were identified with line numbers ICC57C4'and 1CY28B6. In these cases, the fabricator's isometric drawings specified schedule 40 pipe, but the associated design drawings specified schedule 80 for portions of the lines.

Schedule 40 pipe was subsequently provided to Baldwin Associates for installation. These errors were discovered in early 1981 prior to pipe installation and were corrected.

CORRECTIVE ACTION Illinois Power is taking the following steps to correct identified deficiencies and to prevent recurrence:

1. Sargent & Lundy is reviewing their design information for safety-related piping subject to external loading to ensure that the design documents are consistent and adequate. This review is substantially complete and has identified no inconsistencies other than those noted in this report.

2. Sargent & Lundy is reviewing and statusing safety related, augmented D, and Fire Protection related process piping isometric drawings to ensure that the correct wall thickness has been specified for fabrica-tion and installation. This review also includes a comparison of various S&L design documents for consis-tency. This review is substantially complete. Through the end of May, 1983, 1066 drawings had been reviewed.

No additional cases of wall thickness violations have been identified, although other minor problems have been found and are being corrected (e.g. addition of flow arrows, minor dimensional inconsistencies, missing notes, etc.).

3. Remedial action has been determined for lines 1LP21A4 and ILP21B4. The lines will be used as installed, but a penetration sleeve will be modified to shield the pipe from the external loads. This sleeve modification will require a pipe support configuation change.

4. Remedial action for line 1RH03BB12 is being determined.

This action could require external protection of the i pipe, additional hangers, replacement of the pipe, or a i combination of the above.

l 5. Sargent & Lundy is presently, or will be reviewing

! certain contractor's drawings that were previously used l for installation and inspection without a Sargent &

l Lundy review. This review includes, but is not limited to, the following areas:

1. Small bore piping isometric drawings.

2. Instrumentation line isometric drawings.

3. Penetration sleeve drawings.

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.- J. G. Keppler June 17, 1983

4. Penetration head fitting drawings.

5. Thermo-well installation drawings.

6. To reduce the potential for errors in future work, Sargent & Lundy has changed their practice of identify-ing piping wall thickness on the Piping Line List.

7. Illinois Power is conducting a program of technical reviews of S&L's large bore piping design of selected piping subsystems. Three (3) reviews have been conducted to date, with others planned in the future.

It should be noted that a recurrence of this problem is largely precluded by the fact that large bore piping design and fabrication is essentially complete for Clinton.

SAFETY IMPLICATIONS / SIGNIFICANCE The pipelines in question are subject to pool swell impact which produces additional external loads on the piping. Failure of the RHR piping could potentially result in less emergency core cooling flow to the reactor than required by design. Failure of the LP piping in question could result in degraded containment integrity. Although additional investigation and analysis are necessary to evaluate identified problems and to determine remedial action, this deficiency does present an adverse impact on the safety of CPS operations and is considered reportable under 10CFR50.55(e).

It is anticipated that our investigation and analysis will be completed in approximately ninety (90) days. We trust that this interim letter provides sufficient information to perform a general assessment of this deficiency, and adequately describes our overall approach to resolve the problem.

rg) yours,

. . Hall Vice President REC /lf i

cc: Director, Office of I&E, US NRC, Washington, DC 20555 NRC Resident Inspector Illinois Office of Nuclear Safety Manager-Quality Assurance INPO Records Center