ML20042G983

Forwards Safety Evaluation Concluding That Repair or Replacement of Portions of Piping W/Main Steam Line Flaw Not Required.Confirms Util Commitment to Subj Piping W/Flaws to NDE at Each Refueling Outage

ML20042G983
Person / Time
Site:	Calvert Cliffs
Issue date:	05/08/1990
From:	Mcdonald D Office of Nuclear Reactor Regulation
To:	Creel G BALTIMORE GAS & ELECTRIC CO.
Shared Package
ML20042G984	List: ML20042G983 ML20042G985
References
TAC-66454, NUDOCS 9005160371
Download: ML20042G983 (4)

Text

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WASHINGTON, D, C. 20656 k....* p May 8,1990-Docket No. 50-317 Mr. G. C. Creel Vice' President - Nuclear Energy Baltimore Gas and Electric Company Calvert Cliffs Nuclear Power Plant MD Rts.'2 & 4 P. O. Box 1535 Lusby, Maryland:20657

SUBJECT:

JUSTIFICATION OF NON-REPAIR OF A MAIN STEAM LINE FLAW CALVERT CLIFFS NUCLEAR POWER PLANT, UNIT NO. 1

REFERENCE:

TAC Number 66454 By letter dated December 16, 1986, Baltimore' Gas and Electric Company. reported the discovery of a flaw in a main steam'line of Unit 1 consisting-of a smaller wall thickness than allowed by the or.iginal construction-code, ANSI-B31.1-1967.

4Property "ANSI code" (as page type) with input value "ANSI-B31.1-1967.</br></br>4" contains invalid characters or is incomplete and therefore can cause unexpected results during a query or annotation process. To justify continuing operation,until the next refueling outage,' March 1988, you' requested the use of ASME Code'Section XI.-IWB-3600, 1983 Edition 583, which provides for an analytical eyaluation of the flaw to determine its-acceptability for continuini operation.

Your evaluation showed that all relevant criteria were meti exceps for IWB-3610(b) for which relief was. requested.-

This section requires that the prin;ary stress -limits be: met. 'The primary longitudinal stress limit was; met,' but the primary-hoop stress limit was not met. You further comitted to prcdde assurance that' theiaffected piping would meet all applicable requirements of Section XI, 1983, with1S83 addenda. The i

staff granted the'reques a d relief-and ASME code update by letter dated March g

26, 1987, which required you repair or replace the affected pipe at the next' refueling outage.

lo By letter dated September 30,1987, you indicated-that relief from the requirement 1

of'ASME Section,XI 1WB-3610(b) was no longer needed for the' flaw. -A detailed

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finite element analysis of theinffected pipe, which demonstrated that the primary stress limits were being met:under design pressure and dead weight loading as-required by 'lWB-3610(a) was provided as the basis for your conclusion.

1 Additiona1' supporting documentation on the finite element analysis was also' provided by _ letters dated May 4'and June 6,1988. On'this basis, you stated' i

that the requirement that the affected pipe be repaired or replaced was no longer necessary nor applicable.

Your initial submittals also provided-the reselts of~a linear elastic fracture i

mechanics analysis-to demonstrate that an adequate margin ~of safety existed' while operating with the flaw. This, analysis supported the temporary j

relief. By letter dated November 15, 1989, you withdrew the fracture.

mechanics analysis based on the final results of the finite element analysis.

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Mr.'G. C. Creel :

which demonstrates that the intent of the original construction code is met.

Your letter also addressed our concerns relating to procedures to prevent steam line over-pressurization due to steam generator' tube ruptures.

O The staff has reviewed your finite element analysis in relation to the -

f requirements of IWB-3610(b) of the ASME Code,Section XI. The details and results of our review are included in the enclosed Safety Evaluation.

Based on our review, we have determined that the analysis is. acceptable and have concluded that you have reasonably demonstrated that the intent of-ASME B31.1, 1967, and the requirements of IWB 3610(b) have been met, i.e., the.

primary stresses in the affected pipe with the reduced wall thickness satisfy,

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the primary stress limits. We, therefore, conclude that the repair or-replacement of the effected portion of the Main Steam Line is not required.

- However, as indicated in your letter dated April 13,'1990,Lyou have stated that.

the portion of the pipe with the flaw will be subjected to non-destructive

. examination at each refueling outage due to the natureLand location of=the flaw. We consider this prudent and will provide enhanced assurance of the structural integrity of the pipe. You-also indicated that we would be notified of any changes that you may propose to this inspection. requirement in the future.

This completes our activities related te the referenced TAC Number.

Sincerely, ORIGINAL $1GNED BY, Daniel G. Mcdonald, Senior Project Manager Project Directorate 1-1 Division of Reactor Projects - 1/II Office of Nuclear Reactor Regulation

Enclosure:

Safety Evaluation cc w/ enclosure:

See next page DISTRIBUTION Docket Tilt CVogan NRC & Local PDRs DMcDonald PDI-1 Rdg OGC

. SVarga EJordan BBoger ACRS (10)

RCapra ~-

TMarsh MHartzman

• See previous concurrences LA:PD-1 PM:P3-1 EMED D:PD-1 CVogan*

DMcDonald:mes*

LMarsh*

RCapra 4/26/90 4/27/90 4/30/90 5 / 8 /90 b b b k h P b TO CREEL TAC 65454

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Mr." G. C. Creel.

which demonstrates that the intent of the original construction code is met.

Your letter also addressed our. concerns relating to procedures to prevent steam line over-pressurization due to steam generator tube ruptures.

The staff has reviewed your finite element analysis in relation to the requirements of IWB-3610(b) of the ASME Code,Section XI. The details and-results of our review are included in the enclosed Safety Evaluation.

Based'on our review, we have_ determined that the analysis is acceptable and a

have concluded that you have reasonably demonstrated that the intent of ASME B31.1, 1967, and the requirements of.iWB 3610(b) have been met, i.e., the primary stresses in the affected pipe with the reduced wall thickness satisfy the primary stress limits. We, therefore, conclude that the repair or replacement of the effected portion of the Mair. Steam line is not required.

However, as indicated in your letter dated April 13, 1990 you have stated that.

the portion of the pipe with the flaw will be subjected to non-destructive examination at each refueling outage due to the nature and-location of the flaw. We consider this prudent and will provide enhanced assurance of the structural integrity of the pipe. You also indicated that we would be notified of any changes that you may. propose to this inspection requirement in the future.

This completes our activities related to the raferenced TAC Number, q

- S_incerely,

t ORIGINAL S GNED BY:

Daniel G. Mcdonald, Senior Project Manager!

I Project Directorate I-I Division of Reactor Projects - 1/II a

Office of Nuclear Reactor Regulation j

Enclosure:

Safety Evaluation cc w/ enclosure:

See next page-DISTRIBUTION Docket File __

CVogan

- NRC & Local PDRs DMcDonald PDI-1 Rdg OGC SVarga EJordan l

BBoger ACRS (10)

RCapra TMarsh MHartzman

• See previous concurrences i

LA:PD-1 PM:PD-I EMEB D:PD-I CVogan*

0 Mcdonald:mes*

LMarsh*

RCapra 4/26/90 4/27/90 4/30/90 5 / 8 /90 b

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M TO CREEL TAC 65454

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.Mr. G. C. Creel Baltimore' Gas &~ Electric Company Calvert Cliffs Nuclear Power Plant ec:.

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i Mr. William T. Bowen, President Mr. Joseph H. Walter Calvert County Board of Engineering Division 4

Commissioners Prince Frederick, Maryland 20678.

Public Service Commission of Maryland American Building,

231 E. Baltimore Street Baltimore, Maryland D. A. Brune, ESq..

21202-3486

_i General Counsel Baltimore-Gas and Electric Company Ms..Kirsten A. Burger, Esq.

P. O. Box 1475 Maryland People's Counsel Baltimore, Maryland 21203 AmericaniBuilding, 9th Floor 231 E. Baltimore Street' Mr. Jay E. Silberg, Esq.

Baltimore, Maryland 21202 Shaw, Pittman, Potts and Trowbridge 2300 N Street, NW Ms. Patricia Birnie Washington, DC 20037 Co-Director Maryland safe Energy Coalition.

P. O. Box 902 Ms. G. L. Adams, Licensing Columbia, Maryland 21044, Calvert Cliffs Nuclear Power Plant MD Rts 2 & 4, P. O. Box 1535 Lusby, Maryland 20657-Resident ^1nspector c/o U.S. Nuclear Regulatory Commission P. O. Box 437 Lusby, Maryland 20657 i

l Mr. Thomas Magette Administrator --Nuclear Evaluations Department of Natural Resources 580 Taylor Avenue L

Tawes State Office Building l-PPER B3 l

Annapolis, Maryland. 21401 r

Regional Administrator, Region I'.

l U.S. Nuclear Regulatory Commission 475 Allendale Road l

King of Prussia, Pennsylvania 19406 k

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