ML20062H303

QA Program Mgt Corrective Action Rept 33:tendons in Containment Bldg Found to Have Unknown Wire Lengths.Caused by Manufacturer & QA Program Errors.Production Equipment & QA Procedures Being Corrected

ML20062H303
Person / Time
Site:	Midland
Issue date:	07/27/1979
From:	CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:
Shared Package
ML19291B162	List: ML19291B161 ML20062H303
References
HOWE-226-79, NUDOCS 7908290567
Download: ML20062H303 (4)

Text

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buALITY AUSUilANCE l'ROGilAM At.tachment 1-

., f.1ANAGEf.1ENT COHOECTIVE ACTION HEPORT H we-226-79 MCAR 1 .

REPORT NO. 33 JOB NO. _2220 0 NO. 1.1n7 DATE_ July 27, 1979 i ' DESCRIPTION (including rebronces):

1 Section 3.8.1.6.3.2 of the Midland Units 1 and 2 FSAR states in part "The differential l 1ength of any tuo wires in the sc=e tendon up to 100 feet wirc length is i 1/16 inch

and i 1/8 inch for wires longer than 100 feet. Cutting tolerances for overall tendon ,

icngth is i 1/2 inch up to 100 feet and 1 ine.h over 100 feet." These require =ents are reficcted in Inryco Post Tensioning Precedure PT 5.1 (Fabrication Tendons).

Contrary to this requirement tendons were produced with varying unknown uire icngths.

Some tendons were accepted by Inryco QC and 17 tendons were shipped to the Jobsite (Continued on page 2)

• RECOMMENDED ACTION (Optional)

Actions to be acccmplished by supplier. Availabic data to be provided to Bechtel '

Project Engineer on or before August 8, 1979. At that t.lue a schedule for caswering other questions will be provided.

1. Detemine the extent of the hardware probica.

a) Ecv was problem detected.

b) Detemine which tendons are acceptabic for use and provide data and rationale to substantiate. (Continued on page 2)

REFERRED TO O ENGINEERING O CONSTRUCTION OOA MANAGEMENT O CI PROCUREMENT 1

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ISSUED BY . D'a sA1 Project OA Eng.neer Date ,

I il REPORTABLE DEFICIENCY Potentially reportable N IFIED CLIENT O NO l

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Pro;ect Manager

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IWIAGl:Ml:NT CORRECTIVE ACTIO:i REPORT

• ' REPORT 1;0. 33 -

Page 2

, DESCRIPTIO:1 Continued (7 verticals and 10 horizontals). Of the tendons chipped to the Site the 7 verticals ucre inserted into the contain=ent (#2).NCR 2373 was issued placing the tendons at the

, Site on hold. Shipment frca the Florida facility have been placed on hold.

REC 02 ENDED ACTION Continued c) Is the problen limited to those tendons produced at the Ulrc Mill facility in Florida or are the tendons produced at Inryce, Melrose Park,'Ill. also ,

questionabic.

d) If the Melrose Park tendons are considered satisfactory what is the basis for this conclusion.

2. Provide disposition instructions for tendons determined to be bad or questionable.

3. Remedial action to the manufacturing process to prevent similar problems in the future.

I a) Include complete evaluation of manufacturing process.

b) Correction of any deficiencies.

c) Proof of effectiveness of corrective actions.

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4. Remedial action regarding the quality pregram to prevent similar probiccs in the future.

i a) Evaluation of Quality Program.

j b) Correction of deficiencies.

c) Proof of effectiveness of corrective action.

PROJECT ENGINEERINO

1. To evaluate responses from vendor and issue Interim Report on August 10, 1979 to Quality Assurance.

2. Also, determine reportability under 10 CFR 50.55(e) and identify in the l

Interim Report.

a w w--- v- w e w' ~ ' " w -- w-+ y -g n &

' ' Attachm:nb 2 Bechtel Associates Professional Corporation

SUBJECT:

MCAR 33 (Issued 7/27/79)

Differential Wire Length of Containment Building Prestressing Tendons INTERIM REPORT 1 DATE: August 10, 1979 PROJECT: Consumers Power Company Midland Plant Units 1 and 2 Bechtel Job 7220 Introduction This report summarizes project engineering's actions and evaluation to date regarding the differential laagth of prestressing tendons.

Description of Deficiency On July 20, 1979, Inryco, the post-tensioning vendor, informed Bechtel construction that it was placing all tendons manufactured at the Wiremil facility in Florida on hold, due to tendons being manufactured to unknown wire lengths. This is in violation of the Inryco Post Tensioning Procedure PT 5.1, Fabrication-Tendens, and the Midland Plant Units 1 and 2 FSAR Subsection 3.8.1.6.3.2. The commitnent stated that the differential wire length for any two wires in a tendon is + 1/8 inch for tendons over 100 feet. And the cutting tolerances for overall tendon length is 1 1 inch for tendons over 100 feet. There were 17 tendons shipped to the site that uere manufactured in Wiremil. Out of the 17 tendons, 7 are verticala and they have been installed into the sheaths. The remainder are horizontals and they have not been installed. NCR 2373 was issued placing the tendens at the site on hold.

Investinatien An investigation was initiated, with both the Wiremil and Melrose Park facilities being enamined by Ecchtel and CPCo personnel. The finding is that only the tendons produced at the Wiremil facility are of differential wire lengths (33 tendons total). The review of the manufacture /inspectica processes at Melrose Park revealed no irdications that the tendons delivered f rem the Mel rose Park f acility are not in compliance with the FSAR.

The disposition of the 33 tendons in question has not been finalized.

A meeting was held on August 9, 1979, at Melrose Park to discuss the questions presented in MCAR 33 and the draft remedial procedures to correct the deficiencies. The infornation gathered is being evaluated and 10, 1979.

will be included in the nent' report scheduled to be issued on September

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Bechtel Associates ProfessionalCorporation MCAR 33 Interim Report 1 August 10, 1979 Page 2 Safety Implications Project engineering's investigation indicates that the quality assurance program used at the Wiremil facility broke doun. The differential wire lengths in a tendon will cause wire stresses in excess of the design values. The safety margin of the containment structure is'thus reduced from the design conditions as stated in the FSAR. Therefore, the deficiency is considered reportable under 10 CFR 50.55(e). Ilowever, the situation probably would not have adverse effect on plant safety for the following reasons:

1) A tendon is subjected to the maximum stress during the initial prestressing operation, when they are stressed to 80% of the ultimate strength. Therefore, if a tendon can withstand the initial prestressing force, it will not fail during any design condition.

2) Since a tendon experiences the highest stress level during the initial prestressing operation, wires that are overstressed may break. The condition would have been detected as a part of speci-fication requirencnts for broken wire.

3) During the prestressing operation, the jacking force is monitored with calibrated gages and the tendon elongations are checked against calculated values. Any abnormality would be detected and corrective measures vill be made.

Corrective Action At present, the ten horizontal tendons not installed are being shipped back to the Jircmil facility. The disposition ef the seven installed vertical tendons, as proposed by Inryco, is being revicued. Wircmil has ,

initiated corrections to the production equipment to eliminate the source of the length variation problem. A wire length verification procedure is being formulated by Inryco. If the procedure is approved by Ucchtel and CPCo, the shipment of tendons to the site will commence.

Submitted by:

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of Approved by: Y- % - - M'~I<

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- Concurrence hy: [, f d'_ h-n f ' ,/

ER/pd u-8/9/15 ,