ML20205R049

Forwards Safety Evaluation Supporting 861216 & 19 Requests for Relief,Until Next Refueling Outage,From Certain ASME Code Hoop Stress Requirements.Relief Granted to Repair Flaw in Base Metal of Steam Generator Main Steam Line 12

ML20205R049
Person / Time
Site:	Calvert Cliffs
Issue date:	03/26/1987
From:	Thadani A Office of Nuclear Reactor Regulation
To:	Tiernan J BALTIMORE GAS & ELECTRIC CO.
Shared Package
ML20205R051	List: ML20205R049 ML20205R706
References
NUDOCS 8704060188
Download: ML20205R049 (4)

Text

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Docket No. 50-317 Mr. J. A. Tiernan Vice President-Nuclear Energy Baltimore Gas & Electric Company P. O. Box 1475 Baltimore, MD 21203

SUBJECT:

FINAL APPROVAL OF AND SAFETY EVALUATION CONCERNING ASME CODE UPDATE AND RELIEF FOR MAIN STEAM PIPING FLAW AT CALVERT CLIFFS UNIT 1 The Commission staff has completed their review of your requests for ASME Code .

relief and update as provided in your submittals dated December 16, 1986 and December 19, 1986. These requests for ASME Code update and relief were necessitated by your determination of an existing flaw in the base metal of i the #12 steam generator main steam line adjacent to and downstream of weld l #EB-01-1005-05. This weld is located at the second elbow downstream from the l flow restricter. The existing flaw consisted of reduced wall thickness readings as low as 0.86" (minimum required wall thickness is 0.95") in a 1/2" wide bank extending 24" along the circumference of the pipe. This length is

.approximately 22.5% of the pipe's circumference. The pipe is 34" in diameter.

l You are currently required by 10 CFR 50.55a(g)(4)(i) to meet the requirements of Section XI of the 1974 Edition and Addenda through the Summer of 1975 of the ASME Boiler and Pressure Vessel Code.Section XI, Article IWA-3000,

" Standards for Examination Evaluations" requires this type of material and weld flaw (type C-F) be evaluated by comparison to the original construction requirements as provided in ANSI B31.1 - 1967. This flaw does not meet the original construction requirements of a minimum wall thickness of 0.95".

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Your submittal of December 19, 1986 requested to update in accordanca with 10 CFR 50.35a(g)(4)(iv) the ASME Code Section XI requirements for this flaw from  ;

the currently required edition to the 1983 Edition with Addenda through Summer l 1983. This was primarily due to the fact that Article IWB-3600 of the 1983 i Edition provides analytical evaluation techniques superior to those prescribed l l by the 1974 Edition but also because during this cycle (in April 1987) you are.

l required by 10 CFR 50.55a(g)(4)(ii) to update to the 1983 Edition of the ASME l Code,Section XI.

To facilitate this update, a flaw evaluation analysis was provided to satisfy l the requirements of Article IWB-3610(a) of the 1983 Edition of the ASME Code.

In addition, you requested relief until the next Unit 1 refueling outage from the Article IWB-3610(b) requirement that you meet the' primary stress limits of NB-3000. Currently, you do not meet the hoop stress requirement for this l l piping due to the wall thickness being below the minimum specification.

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Mr. J. A. Tiernan The Comission letter of December 19, 1986 provided interim approval of your request to update the above identified #12 steam generator main steam line flaw to the requirements of the 1983 Edition with Addenda through Sumer 1983 of Section XI of the ASME Boiler and Pressure Vessel Code. In addition, this letter provided interim relief for this flaw only from the 1983 Edition Section XI Article IWB-3610(b) requirements for primary stress limits.

The Commission has determined that your requests, for this main steam piping flaw only,1) to update the ASME Code Section XI requirements to the 1983 Edition with Addenda through Summer 1983 and 2) to provide relief from the requirements of Article IWB-3610(b), are acceptable as set forth below.

The Commission approves this update request to the 1983 with Addenda through Summer 1983 to Section XI of the ASME Code for this flaw. Furthermore, relief is granted for this flaw from the requirements of IWB-3610(b) until the next Unit I refueling outage. The staff has determined that the requirements of the code are impractical and that pursuant to 50.55a(g)(6)(1), the relief is authorized by law and will not endanger life or property or the commen defense and security and is otherwise in the public interest, giving due consideration to the burden upon the licensee that could result if the requirements were imposed on the facility. The basis for the approval of these requests is that

1) the affected pipe retains adequate fracture toughness, 2) a limit load analysis shows sufficient wall thickness remains to prevent yielding, 3) the affected pipe will be replaced or repaired at the next refueling outage, and

4) the affected pipe is an isolated case.

Our Safety Evaluation is enclosed.

Sincerely, Ori61nal signed by Ashok Thadani Ashok C. Thadani, Director PWR Project Directorate #8 Division of PWR Licensing-B

Enclosure:

Safety Evaluation i cc w/ enclosure:

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Mr. J. A. Tiernan The Comission letter of December 19, 1986 provided interim approval of your request o update the above identified #12 steam generator main steam line flaw to t requirements of the 1983 Edition with Addenda through Summer 1983 of Section of the ASME Boiler and Pressure Vessel Code. In addition, this letter provi d interim relief for this flaw only from the 1983 Edition Section XI Art le IWB-3610(b) requirements for primary stress limits.

The Commission ha determined that your requests, for this main steam piping flaw only, 1) to up ate the ASME Code Section XI requirements to the 1983 Edition with Addenda through Summer 1983 and 2) to provide relief from the requirements of Artic IWB-3610(b), are acceptable.

The Commission approves is update request to the 1983 with Addenda through Summer 1983 to Section XI f the ASME Code for this flaw. Furthermore, relief is granted for this flaw from the requirements of IWB-3610(b) until the next Unit 1 refueling outage. Thh basis for the approval of these requests is that

1) the affected pipe retains adequate fracture toughness, 2) a limit load analysis shows sufficient wall hickness remains to prevent yielding, 3) the affected pipe will be replaced o repaired at the next refueling outage, and

4) the affected pipe is an isolat case.

Our Safety Evaluation is enclosed.

Sincerely, 4

Ort Air /24 Pt Frin~kJ. iraglia, Director Division o PWR Licensing-B Office of N lear Reactor Regulation

Enclosure:

Safety Evaluation cc w/ enclosure:

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,1 Mr. J. A. Tiernan l Baltimore Gas & Electric Company Calvert Cliffs Nuclear P.ower Plant cc:

Mr. William T. Bowen, President Regional A&inistrator, Region I Calvert County Board of U.S.-Nuclear Regulatory Commission Commissioners Office of Executive Director Prince Frederick, Maryland 20768 for Operations 631 Park Avenue D. A. Brune, Esq. '

King of Prussia, Pennys1vania 19406 General Counsel Baltimore Gas and Electric Company P. O. Box 1475 Baltimore, Maryland 21203 Jay E. Silberg Shaw, Pittman, Potts and Trowbridge 2300 N Street, N.W.

3. Washington, DC 20037 Mr. M. E. Bowman, General Supervisor Technical Services Engineering Calvert Cliffs Nuclear Power Plant MD Rts 2 & 4, P. O. Box 1535 Lusby, Maryland 20657-0073 Resident Inspector c/o U.S. Nuclear Regulatory Commission P. O. Box 437 7

Lusby, Maryland 20657-0073 8echtel Power Corporation ATTN: Mr. D. E. Stewart Calvert Cliffs Project Engineer 15740 Shady Grove Road Gaithersburg, Maryland 20760 Combustion Engineering, Inc.

ATTN: Mr. W. R. Horlacher, III ,

Project Manager P. O. Box 500 1000 Prospect Hill Road Windsor, Connecticut 06095-0500 Department of Natural Resources Energy Administration, Power Plant Siting Program ATTN: Mr. T. Magette l Tawes State Office Building Annapolis, Maryland 21204 l

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