IR 05000341/1985045

Insp Rept 50-341/85-45 on 851008-09.No Violation or Deviation Noted.Major Areas Inspected:Failure of 30-inch Steam Bypass Line & Licensee Actions on Previous Insp Findings

ML20138N058
Person / Time
Site:	Fermi
Issue date:	10/31/1985
From:	Danielson D, Jeffrey Jacobson, Muffett J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
To:
Shared Package
ML20138N054	List: IR 05000341/1985045 ML20138N048
References
50-341-85-45, NUDOCS 8511050041
Download: ML20138N058 (3)

Text

.

4

.

U.S. NUCLEAR REGULATORY COMMISSION

REGION III

Report No. 50-341/85045(DRS)

Docket No. 50-341 License No. NPF-33

. Licensee: Detroit Edison Company

"

2000 Second Avenue Detroit, MI 48224 Facility Name: Enrico Fermi Atomic Power Plant, Unit 2

,

Inspection At: Enrico Fermi Site, Monroe, MI Inspection Conducted: October 8 and 9, 1985

- .

^Qg ) ;

.

Inspect s: Jacobso /0/3/ / ff'

Date

%@

J. Muffett to/si[g5 Dat'e /

Approved By: D. Danielson, Chief j Materials and Processes Section lo/3/

Date Inspection Summary Inspection on October 8 and 9, 1985 (Report No. 50-341/85045(DRS))

Areas Inspected: Special announced safety inspection of the 30" steam bypass line failure; and licensee actions on previous inspection finding The inspection involved 18 inspector-hours onsite by two NRC inspectors.

-

Results: No violations or deviations were identifie DR ADOCK 050003 1

,

,-,,,r,,, . - - . . . - - . _ , ,~r, , - _ . . , . . . . , - - . . - - _ . - , ~ - , - . -

-

- - - . , ~ y -- -._._-r_~ ...r,..-. , .

. . - ._ .

.

DETAILS 1. Persons Contacted Detroit Edison Company (DECO)

J. Conen, Licensing Engineer J. Mullens, Welding Engineer ,

• D. Spiers, Director, Field Engineering

• S. Noetzel, Assistant Manager

• M. Williams, Senior Engineer

• T. O'Keefe, Superintendent, Nuclear Engineering

• Denotes those attending the exit meeting on October 9, 1985

2. Licensee Action on Previous Inspection Findings (Closed) Violation (341/85038-01(DRS)): Failure to properly qualify a welding procedure in accordance with the AWS 01.1 Cod Procedures used by the electrical contractor L. K. Comstock (LKC),

,

to weld cable ~ trays and supports did not address fillet size as required by the Code for "prequalified" statu The licensee initiated DER No.85-640 to document this deficienc Per the Detroit Edison Specification 3071-128, the smallest fillet weld attaching structural steel is 3/16 of an inc In order to evaluate work previously completed by LKC, the licensee conducted weld procedure qualification tests simulating the most severe field conditions with regard to minimum size multi pass fillet welds. The The qualifications are documented in Engineering Research Report No. 83E72-40. These qualifications were performed in accordance with LKC procedure WI-000-03001 in the horizontal, vertical and overhead positions. In order to verify the adequacy of other site contractors with regard to this deficiency, a review of their

"prequalified" weld procedures was conducted by the licensee. All documentation was reviewed by the NRC inspector. This qualification testing is considered an acceptable resolution of this ite (Closed) Open Item (341/85038-02(DRS)): Linear indications on radial box beam 5028. Calculations performed by Sargent and Lundy Engineers (SLS-EF-099, Calc NP-Al and NS-E2-D23BF) to resolve NCR 84-1839 were reviewed by the NRC inspector and found to be acceptable. Based on the review of this analysis, this item is considered close . Review of Steam Bypass Line Failure The 30 inch diameter Steam Bypass Lines have experienced the development of a number of large cracks as well as damage to lugs and pipe restraint Although this line is not safety-related, due to its relative importance

r

.

.

to safe plant operations, a review of the licensee's actions concerning this problem was performed. Items reviewed during this inspection included:

• Operational history of the Steam Bypass Lines

• Licensee's evaluation of the cause of the cracking

• Results of readings from the instrumentation installed on the pipe

• Techniques used to repair the cracks

• Results of metallurgical tests conducted on a sample removed from an area of the cracked pipe The NRC inspectors concluded after this review that the Steam Bypass Lines were experiencing very acute fatigue induced failure. This is unusual in that the lines have a very short (approximately 2 months) operational history and that the unit has been limited to 5% of rated power. It appears that the fatigue problem is related to two factors. The first t'eing the large diameter thin wall configuration of the piping (30 inch diameter, 0.375 inch wall). The second being the high frequency acoustic vibrations induced by the steam bypass valves. A permanent modification to address the fatigue problem must consider both of these factor Additionally, during the NRC inspection the licensee discovered a new crack which had developed since the last repair. The NRC inspectors concluded that further failure of the lines was imminent and that continued operation represented a significant risk to safe operation of the unit. The licensee agreed to shut the unit down and initiate replacement of the damaged piping. No violations or deviations were identifie The NRC plans to review this matter furthe This is an open item (341/85045-01).

4. Exit Interview The inspectors met with licensee representatives (denoted in Persons Contacted paragraph) at the conclusion of the inspection. The inspector summarized the scope and findings of the inspections noted in this report. The inspector also discussed the likely informational content of the inspection report with regard to documents or processes reviewed by the inspector during the inspection. The licensee did not identify any such documents / processes as proprietar