ML20028C128

Interim Deficiency Rept Re Increase of Investigation Scope for Small Bore/Instrumentation Piping Support Design Calculations.Initially Reported on 820902. Hold Imposed on Electrical Conduit Hanger Calculation Activities

ML20028C128
Person / Time
Site:	Clinton
Issue date:	12/21/1982
From:	Hall D ILLINOIS POWER CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
10CFR-050.55E, 10CFR-50.55E, 82-09, 82-9, U-10014, NUDOCS 8301070089
Download: ML20028C128 (5)

Text

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b/1/W 1605-L ILLIN0/8 POWER 00MPANY U-10014 CLINTON POWER STATION. P.O. BOX 678, CLINTON, ILLINOIS 61727 December 21, 1982 Docket Number 50-461 Mr. James G. Keppler Regional Administrator Region III U.S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137

Subject:

Potential Deficiency 82-09 10 CFR50. 55 (e)

Small Bore / Instrumentation Piping Support Design Calculations

Dear Mr. Keppler:

On September 2, 1982, Illinois Power notified Mr. P. Pelke, NRC Region III (ref: IP memorandum Y-13910, 1605-L, dated September 2, 1982) of a potentially reportable deficiency concerning discrepancies identified by Illinois Power in a sample of small bore / instrumenta-tion piping support design calculations performed by Sargent & Lundy (CPS Architect-Engineer). This initial notification was followed by one (1) interim report (ref: IP letter, D.P. Hall to J.G. Keppler, U-0555, 1605-L, dated October 1, 1982), wherein it was anticipated that an additional ninety (90) days would be required to complete the investigation and file a final report on the natter. Investigation by Illinois Power has identi'ied similar discrepancies in the Architect-Engineer's calculations supporting the design of electrical conduit hangers. Therefore, it is Illinois Powers' intent to increase the scope of this investigation to include these errors and to investigste other similar areas of Sargent & Lundy's design. This letter is submitted as an interim report in accordance with 10 CFR50. 55 (e) ( 3 ) and provides background information with regards to this increase of investigation scope.

Statement of Potentially Reportable Deficiency An independent review by Illinois Power Nuclear Station Engineering Department (NSED) personnel of Sargent & Lundy's calculations for small bore / instrumentation piping supports and electrical conduit hangers identified errors in the calculations.

0301070089 821221 DEC 2I E6 PDR ADOCK 05000461 S PDR

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Mr. James G. Keppler HRC Page 2 of 5 Resolution of the errors could result in changes to pipe and elec-trical conduit supports released for construction, or require the installation of additional supports. An evaluation is being per-formed to determine (1) the magnitude and significance of these errors, (2) the potential for errors in other areas of design performed by similar methods, (3) the impact on installed hardware, and, (4) the potential for adverse impact on the safety of operations of Clinton Power Station.

Background / Investigation Results As a result of previously reported calculation errors in the area of small bore piping hangers, NSED performed a review of a sample of Sargent & Lundy's conduit hanger calculations. This review was performed during the period September 14, 1982 through October 22, 1982, and included a detailed review of one hundred twenty five (125) electrical conduit hanger calculations, twenty five (25) selected from each of five (5) seismic category I buildings (auxiliary, control, diesel-generator, containment, and fuel). The results of this review were tabulated by USED as follows:

I. Calculation conservative, hanger suitable................. 68 II. Calculation discrepancy, hanger considered suitable....... 41 III. Calculation discrepancy, hanger not considered suitable.... 3 IV. Calculation discrepancy, hanger suitability indeterminate. 13 Total calculations reviewed....... ...................... 125 An evaluation of the discrepancies identified in categories II, III, and IV was completed by Sargent & Lundy and showed that, although calculation discrepancies exist, the hangers are adequate as designed. However, investigation continues in this area to determine the magnitude of these discrepancies and the potential for discrepancies in other design areas.

Investigation into calculation discrepancies associated with small bore / instrumentation piping hangers is continuing. A hold was placed by Sargent & Lundy on small bore piping support design documents until the matter was fully investigated and corrective action was implemented. Sargent & Lundy has performed a review of the 324 safety related small bore / instrumentation pipe calculations performed to date and identified 134 calculations which contain non-conservative descrepancies to the requirements of the small piping procedure, EMD-015666. The piping designs with these errors were further evaluated by Sargent & Lundy using computer analysis or detailed hand calculations, and the results showed compliance with the ASME Code. These calculations will be revised to conform with the rules of EMD-015666, which will result in some hardware changes.

Twenty five (25) calculations of small bore / instrumentation piping were found to be out of compliance with both EMD-015666 and the ASME Code. Calculation revisions will be made, and will result in hardware changes to bring the affected subsystems into compliance l

Mr. James G. KepP l er o NRC Page 3 of 5 with EMD-015666 (and the ASME Code). A Sargent & Lundy analysis of these 25 calculations has been performed, which showed that none of the discrepancies were significant and would, therefore, not affect adversely the safety of operation of CPS.

An Illinois Power Special Surveillance has been performed to veri fy adequacy of corrective action taken by Sargent & Lundy on this matter. This surveillance showed that the corrective action taken by Sargent & Lundy was adequate to prevent recurrence of the types of error detected in the small bore piping support calculations. As a result of this positive evaluation, Illinois Power authorized Sargent

& Lundy to release the hold on design documents for small bore piping supports. Illinois Power is continuing its review of the technical adequacy of the Sargent & Lundy small bore piping procedures, which includes an assessment of the re-review process, the adequacy of procedures for small bore / instrumentation pipe hanger design, and appraisal of the significance of the discrepant calculations.

Corrective Action (Interim)

Illinois Power Company has met with Sargent & Lundy Project Management to discuss and develop a course of action to fully investigate the scope of the calculation errors, root causes of the errors, and impact on installed hardware. Several interim corrective action measures have been established and are being taken by Illinois Power and Sargent & Lundy, as follows:

Conduit Supports

1. A hold (as of December 13, 1982) on electrical conduit hanger calculation activities has been imposed, until further investigation is performed and appropriate corree-tive actions have been taken and found acceptable by Illinois Power Company and Sargent & Lundy Ouality Assurance.

2. Sargent & Lundy Quality Assurance will perform an audit of electrical conduit hanger calculation activities to assess program adequacy and determine necessary corrective actions.

3. A formal retraining program in the requirements for the design of electrical conduit hangers is being developed and will be implemented.

4. Illinois Power and Sargent & Lundy Ouality Assurance will initiate audits in other areas of the Clinton design performed using procedures similar to the conduit hanger and small bore pipe hanger procedures (repetitive calculations prepared by a large group of personnel, based on simplified procedural type of analysis) to assure that similar conditions do not exist.

Hr. James G. Keppler.

URC Page 4 of 5

5. Sargent & Lundy will perform a review of electrical conduit hanger calculations performed to date, to determine the extent and nature of the errors and to assess the adequacy-of existing design documents.

6. Illinois Power Quality Assurance will perform audits / ,

surveillances of Sargent & Lundy's actions on this matter to assess adequacy in correcting the calculation errors, and effectiveness in preventing recurrence of errors.

7. Illinois Power will expand its technical review activities of Sargent & Lundy's design. The exact scope of this effort has not been established, but it will increase IP's present reviews.

Small Bore / Instrumentation Piping Supports

8. Sargent & Lundy procedures for small bore / instrumentation hanger design have been expanded and clarified to enhance the design process. These enhancements include:

instituting a checklist to be used by the independent reviewer of calculations to assure an adequate reviews locating an analyst on site to review and concur with procedural interpretations; and locating copies of piping system stress reports at the site for first-hand reference.

9. Personnel responsible for preparing and reviewing small bore / instrumentation component support calculations have been given training in the requirements of the revised procedures.

10 Calculations which contain nonconservative errors will be reconciled or revised. This action was authorized by Illinois Power to begin on December 20, 1982, and is estimated to be complete by May 31, 1983.

Safety Implications / Significance A review of calculation discrepancies in the area of electrical conduit hangers and small bore / instrumentation piping hangers is presently on-going, to determine the adequacy of the hangers. When the results of this review are complete, the identified discrepancies will he evaluated to determine impact on plant hardware and significance on plant safety. The results will also be analyzed for trends which will aid in identifying root cause and evaluating the need for additional generic corrective action. Illinnis Power intends to provide an update of the investigation and status of corrective action taken by March 21, 1983. At that time it is expected that further details as to the significance and reportability of this potential deficiency can be provided.

Mr. James G. Keppler 1 - PIRC Page 5 of 5 Ue trust that this interin letter provides sufficient informa-tion to perform a general assessment of this deficiency and overall approach to resolution of the problem, i

! Verv truly yours, i

1

. . Iall l Vice President j cc: 11.11. Livernore, tiRC Resident Inspector Director, O#fice of I&E, USNRC, Washington, D.C. 20555 '

T.llinois n#fice of fluclear Safety Director-Ouality Assurance t

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