ML20038B922

Final Deficiency Rept Re Reactor Vessel Broken Anchor Bolt, Initially Reported 790914.Forwards 811130 Bechtel Rept.Stud Failures Caused by Excessive Hardness Due to Improper Heat Treatment

ML20038B922
Person / Time
Site:	Midland
Issue date:	12/01/1981
From:	Jackie Cook, Jackie Cook CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
10CFR-050.55E, 10CFR-50.55E, 14625, NUDOCS 8112090296
Download: ML20038B922 (5)

Text

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C00sumels POW 8r James W Cook OhfOf Vice President - Projects, Engio.eering and Construction cene,.s offices: 1945 West Pernail Ho sd, Jackson. MI 49201 + (517) 788-0453 79-10 #12 December 1, 1981 Lb / A g.V

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9 Mr J G Keppler, Regional Director 1981

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office of Inspection & Enforcement US Nuclear Regulatory Cocaission DEC7 Region III

,,a sice M o** 7 799 Roosevelt Road

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-\\$p Glen Ellyn, IL 60137 (W

MIDLAND FROJECT -

DOCKET NOS 50-329, 50-330 UNIT NO 1, REACTOR VESSEL BROKEN ANCHOR BOLT FILE:

0.h.9 35 SERIAL: 1h625

References:

1.

Consumers Power Letters to J G Keppler, Same Subject a.

Howe-267-79 dated October 12, 1979 b.

Howe-311-79 dated December lh,1979 c.

Howe-51-80 dated March 3, 1980 d.

Howe-80-80 dated April 30, 1980 e.

Serial 8971 dated May 16, 1980 f.

Serial 8809 dated August 1, 1980 g.

Serial 9330 dated July 2h, 1980 I

h.

Serial 9787 dated December 10, 1980 l

1.

Serial 1152h dated March 31, 1981 j.

Serial 12051 dated July 17, 1981 l

k.

Serial 15035 dated November 23, 1981 l

2.

J G Keppler Letter to S H Howell, Docket Nos 50-329 and 50-330 dated August 18, 1980 3

R L Tedesco Letter to J W Cook, Docket Hos 50-329 and 50-330 dated March 6,1981 4.

D S Hood Letter to Consumers Power dated July 7,1980 References 1 (a) through (k) were interim 50 55(e) reports concerning the Unit No 1 Reactor Vessel Broken Anchor B-olt problem. This letter is the final report on this subject. provides a summary of the actions which have been taken to correct this problem.

WRB/1r 8112090296 811201

.DEC -- 3 1981 yg.2 7 -

PDR ADOCK 05000329 S

P.DR

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!!o Serial lh625 2

'79-10 #12 A : MCAR 37, Final Report, " Broken Reactor Vessel Anchor Stud l

in Unit 1", dated November 30, 1981 j_

CC: Director of Office of Inspection & Enforcement (15) l Director, Office of Management, Infornation & Program Control (1)

RJCook, NRC Resident Inspector, Midland Nuclear Plant (1)

CBechhoefer, ASLB RSDecker, ASLB FPCowan, ASLB l

JHarbour, ASLB l

AS&L Appeal Panel MMCherry, Esq MSinclair BStamiris l

CRStephens, USNRC HDenton, NRC (5)

DSHood, NRC (2)

WDPaton, Esq, USNRC I

EJKelley, Esq, Attorney General SHFreeman, Esq, Asst Attornel General i

WHMarshall

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GJMerritt, Esq, TNK&J l

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l Serial 14625 79-10 #12 Bechtel Associates Professional Corporation 050403 050488

SUBJECT:

MCAR 37 (issued 12/28/79)

Broken Reactor Vessel Anchor Stud in Unit 1 FINAL REPORT DATE:

November 30, 1981 PROJECT:

Consumers Power Company budland Plant Units 1 and 2 Bechtel Job 7220 In,ttaduction The discrepancies discussed in this report concern the failed reactor pressure vessel (RPV) anchor studs in Unit 1 and the method of repair.

Background

The anchor studs in question are 2-1/2 inches in diameter and 7 feet, 4 inches long, embedded in the reinforced concrete RPV pedestal. The anchor studs were purchased from Mississippi Valley Structural Steel of St. Louis, Missouri; fabricated by Southern Bolt and Fastener of Shreve-port, Louisiana; and heat-treated by J.W. Rex of Lansdale, Pennsylvania.

These studs were received on site by Bechtel in early 1976, embedded in concrete by Bechtel in April 1977, and tensioned by Babcock & Wilcox Construction Company in late July 1979.

The first stud failure was discovered on September 14, 1979. The second and third stud failures were reported on December 20, 1979, and February 5, 1980, respectively.

Investigative Action Teledyne Engineering Services (TES) performed a metallurgical failure analysis for Bechtel. The resulting reports (References 1, 2, and 3) discuss the stud failure investigation and the use of the present studs for service.

In a separate report, (References 4 and 5) the root cause of the studs' failure was established by TES, acting for Consumers Power Company. The cause of the failures is the excessive hardness of the studs which is due to improper heat treatment.

Because of concern over the remaining 93 installed anchor studs, design modifications were proposed in Reactor Pressure Vessel Support Modification Reports 1 and 2 (References 6 and 7).

The methods of design and analysis actually used for the modifications are discussed in detail in Support Modification Report 3 (Reference 8).

The studs have been detensioned to a nominal stress of 6 ksi.

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i Bechtel Associates Professional Corporation 050403 050488 MCAR 37 Final Report November 30, 1981 Page 2 Detailed design for the modifications to the upper lateral support (ULS) brackets was completed based on preliminary loads provided by B&W (see Reference 8) for the accident condition of a combined seismic and loss-of-coolant accident (LOCA). Design drawings were issued and construction is complete. It was also determined that machining a flat surface on the reactor vessel to match a flat surface on the ULS was required. B&W determined that it was feasible to machine the vessel, and machining has been completed.

B&W completed an analysis (see Reference 8) to determine the thermal movement of the ULS relative to the vessel at temperatures experienced during operation, hot standby, and transients. A specification is in preparation describing the procedure for the gap measurement during hot functional testing.

The forecast date for issue of this specification is June 30, 1982.

The status of the B&W final analysis of the nuclear steam supply system for the reactor vessel support loads (as described in Reference 8) is as follows:

the seismic analysis has been completed; the LOCA analyses are in progress and will be completed by December 31, 1982. These loads will be reviewed by Bechtel to determine the acceptability of the design. This work will be completed by January 31, 1983.

Bechtel has contracted with Raymond Bolting Services to provide consul-ting services during anchor stud retensioning. A specification for reten-sioning the studs to less than 6 ksi (5.0 + 0.5 ksi) has been issued for use.

In addition, this specification addresses detensioning, proof testing, and recording lift-off data for the Unit 2 anchor studs. The lift-off data will be used to aid in evaluating Unit I lift-off data scatter. This evaluation is in response to a verbal NRR question on the root cause of the anchor stud failures. Detensioning and retensioning of the atuds and evaluation of the scatter of the Unit 1 lif t-of f data will be completed by_Navember 31, 1982.

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CcTcMcL Corrective Action The TES reports (References 1 through 5) address the actions identified in MCAR 37, dated December 28, 1979, Items 1 through 4.

Item 5 of this MCAR will be completed through contract with Raymond Bolting Services by October 31, 1982, as identified above.

Item 6 of the MCAR regarding pro-curement, installation, and tensioning of bolts in similar installations is being handled in MCAR 45, issued December 17, 1980.

Item 7 of MCAR 37, status reporting, resulted in two initial reports, Reactor Pressure Vessel Support Modification (References 6 and 7), and a final report (Reference 8) which supersedes the two initial reports.

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Bechtel Associates ProfessionalCorporation MCAR 37 050403 050488 Final Report November 30, 1981 Page 3 Safety Implications If uncorrected, this deficiency could have adversely affected the safety of operation of the Midland plant at any time throughout the plant's expected life.

Reportability This con.,1 tion was reported to the NRC by Consumers Power Company under 10 CFR 30.55(e) on September 14, 1979.

Submitted by:,f; I b*

Approved by: D-vb Llo(ca ta k

Concurrence by:

SS/ LED /cs

Attachment:

List of References

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050403 LIST OF REFERENCES 050488 1.

Teledyne Engineering Services Report, TR-3887-1, Rev 1, Investigation of Preservice Failure of Midland RV Anchor Studs, May 15, 1980 (CPCo Serial 8971, 5/16/80)

TeledyneEngineeringServicesReport,TR-3887-2,Rev1,kcceptability 2.

for Service of Midland RV Anchor Studs, May 20, 1980 (CPCo Scrial 8971, 5/16/80) 3.

Teledyne Engineering Services Report, TR-3887-1, Addendum 1, Investigation of Preservice Failure of Midland RV Anchor Studs, June 6, 1980 (CPCo Serial 9124, 6/12/80) 4.

Teledyne Engineering Service Report, TR-4599-1, Continued Inven,tigation of the Failure of Midland Unit 1 RV Anchor Studs - Data Report, February 11, 1981 (CPCo Serial 11524, 3/31/81) 5.

Teledyne Engineering Services Report., TR-4599-2, Continued Investigation of the Failure of M1dland Unit 1 RV Anchor Studs - Analysis Report, February 11, 1981 (CPCo Serial 11524, 3/31/81) 6.

Reactor Pressure Vessel Support Modification for Midland Nuclear Power Plant, Report 1, July 1980 (CPCo Serial 9330, 7/24/80) 7.

Reactor Pressure Vessel Support Modification for Midland Nuclear Power Plant, Report 2, December 1980 (CPCo Serial 9787, 12/10/80) 8.

Reactor Pressure Vessel Support Modification for Midland Nuclear Power Plant, Report 3, November 1981 (CPCo Serial 15035, 11/25/81)

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