ML19337A637

Deficiency Rept Re High Energy Line Break Analysis of Pipe Whip Restraint Designs.Caused by Misinterpretation of BN-TOP-2.Affected Restraints re-evaluated.Next Rept by 801121

ML19337A637
Person / Time
Site:	Midland
Issue date:	09/19/1980
From:	Jackie Cook CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
10CFR-050.55E, 10CFR-50.55E, 8830, NUDOCS 8009290360
Download: ML19337A637 (6)

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f,eneral Of f scos: 194'., West Parnali fload, Jackson, Michigan 49201 *(517) 788 0040 September 19, 1980 Mr J G Keppler, Regional Director Office of Inspection & Enforcement US Huclear Ragulatory Commission Region III 799 Roosevelt Road Glen Ellyn, IL 60137 MIDLAND HUCLEAR PLANT UNIT NO 1, DOCKE" no 50-329 UNIT NO 2, DOCKET NO 50-330 HELBA RESTRAINT DESIGN FILE: 0.1.9.11 UFI: 73*10*01 SERIAL:

4 4 8830 This letter confirms the 50.55(e) item concerning HELBA Restraint Design, reported by telephone call to R Knop, USNRC Region III, Glen Ellyn, IL, on August 21, 1980.

The attachments to this letter describe the conditions and actions taken concerning this item.

Another report, either interim or final, vill be sent on or before December 1, 1980.

WRB/lr

Attachment:

1) Management Corrective Action Report (MCAR-1), Report No 10, 4 dated August 21, 1980

2) MCAR 140, Interim R'eport 1, High Energy Line Break Analysis (HELBA), Pipe Whip Restraint Designs, dated September 11, 1980 CC: Director of Office of Inspection & Enforcement Att Mr Victor Stelio, USNRC (15)

Director of Office of Management Information and Prcgrnm Control, USNRC (1)

R Cook, USNRC Reninent Inspector

- Midland Nuclear Plant (1) l 8009200860 $

QUALITY ASSURANCE PROGRAM Attachment 1 MANAGEMEfJT CORRECTIVE ACTION REPORT Serial: 8830 MCAR1 REPORT NO.'

722R1 13.0_L ONO.: 1.io2 03,e 8/21/ 80 JOB NO.: __

l DESCRIPTION * (including Rcterences):

Contrary to the requirements of FSAR 3.6.2.2 and the referenced sections of BN-TOP-2, steady state rather than peak thrust forces were used in the design of Q-listed pipe whip restraints. Design documents have been release 1 for construction /

fabrication purposes and most of the restraints have been installed.

SECOMMENDED ACTION * (Optional):

't . The high energy line break analysis (llELBA) group to develop and provide the civil and plant design disciplines with data necessary to perform a reanalysis of the pipe whip restraint designs to assure t.hcir compliance with FSAR subsection 3.6.2.2.

REFERRED TO: DC Engineering O Constru:: tion O OA Management O ISSUED BY:  ?

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td/'(l PGA_E, lPotentially 11 REPORTABLE DEFICIENCY: l Reportable NOTIFIED CLIENT: .f

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CORRECTIVE ACTION TAKEN:

AUTHORIZED BY:

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'Descrite in sp. ice provided and attach reference document Pro,cc e on t eg nee, on umom Section Number Page of

!! CAR 40

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• REC 0!e!E!!DED AO'l013 04tinued

2. The plant design discipline to develop and provide plastic hinge lengths for the reanalysis of the pipe whip restraint designs.

3 The civil discipline to review affected pipe whip restraint design documents, considering the peak thrust forces, to assure that they shall perform adequately during a high energy pipe . rupture.

If necessary revise design documents.

4. Ibvc the cognizant Chief Engineers office review the IIELBA group assumptions and work processes to determine if other similar potential prob 1 cms exist.

5 If thru the review process certain pipe whip restraints are identified as requiring ' modification, notify Construction, Quality Control and the PQAE.

This notification should be provided as soon as practical after the necessary modification is identified.

6. Investigate and identify the root cause and provide corrective action to preclude recu::rence.

7. Develop and submit a written report to the PQAE for coordination with Consumers Power Compa,ny containing available information on or before 9/11/80.

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Attachment 2

,. ,. Serial 8830 Bechtel Associates Professional Corporation 0iI9I8

SUBJECT:

MCAR 40 (issued 8/21/80)

High-Energy Line Break Analysis (HELBA),

Pipe Whip Restraint Designs INTERIM REPORT I DATE: September 11, 1980 PROJECT: Consumers Power Company Midland Plant Units 1 and 2 Bechtel Job 7220 Introduction This report is submitted regarding the interim status and actions pursuant to the subject MCAR.

Description of Discrepancy FSAR Section 3.6.2.2 states that the analysis of the thrust forces which result in the event of a pipe rupture is described in BN-TOP-2. Con-trary to the intent of BN-TOP-2, the steady-state thrust forces rather than the transient peak thrust forces were used in the energy balance techniques for the design of HELBA pipe whip restraints (see attachment, Figure B). Design documents have been released for construction /fabri-cation and most of the restraints have been installed.

Cause The c9use of this discrepancy has been identified as a misinterpretation of the req;irecents of BN-TOP-2.

Safety Implication The safety-related function of a pipe whip restraint is to limit pipe movement following a high-energy line break to prevent unacceptable damage to essential systems or components. Designing the restraint using the steady-state thrust force instead of the higher transient thrust force could compromise this safety function. The size of the restraints may be inadequate for the increased loads, and/or their location may be inadequate as a higher thrust force may cause the plastic hinge length to decrease outside the range of the restraint. This deficiency, were it to have remained uncorrected, may have adversely affected the safety of operations at the Hidland plant if certain types of accidents were to occur.

Analytical Reevaluation Action The affected restraints are being reevaluated using conservative thrust l force time-histories input to energy balance and/or time history methods as described in BN-TOP-2.

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Bechtel Associates Professional Corporation 0i1918 MCAR 40 Interim Report 1 September 11, 1980 Page 2 Corrective Action Corrective action depends upon the results of the analytical reeva)uation.

Forecast Dates The next interim report is scheduled to be issued by November 21, 1980.

Reportability This condition was reported by Consumers Power Company to the NRC as a potential 10 CFR 50.55(e) reportable condition on August 21, 1980.

A 30-day report is due to be sent to the NRC on September 20, 1980.

Submitted by:

Approved by: 1 J [NO,B.PS Concurrence by: / q_

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