ML20070M074

Forwards Addl Info Re Steam Generator NDE & Reactor Vessel Core Support Cone Structural Integrity, in Response to Questions Raised at NRC 821208 & 1122-24 & ACRS 820818 Meetings

ML20070M074
Person / Time
Site:	Clinch River
Issue date:	01/11/1983
From:	Longenecker J ENERGY, DEPT. OF
To:	Check P Office of Nuclear Reactor Regulation
Shared Package
ML20070M075	List: ML20070M074 ML20070M080
References
HQ:S:83:181, NUDOCS 8301120257
Download: ML20070M074 (3)

Text

Department of Energy Washington, D.C. 20545 Docket No. 50-537 HQ:S:83:181 JAtt J J 1993 Mr. Paul S. Check, Director CRBR Program Office Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D.C. 20555

Dear Mr. Check:

ADDITIONAL INFORMATION ON STEAM GENERATOR NON-DESTRUCTIVE EXAMINATIONS (NDE)

AND REACTOR VESSEL (RV) CORE SUPPORT CONE STRUCTURAL INTEGRITY Enclosure 1 to this letter provides additional infomation concerning NDE of the Clinch River-Breeder Reactor Plant (CRBRP) steam generator. This infor-mation responds to questions raised at the December 8,1982, project / Nuclear Regulatory Commission meeting regarding in-service inspection of the steam generator module.

Enclosure 2 to this letter provides a report on CRBRP RV core support cone structural integrity. This information responds to questions raised at the August 18, 1982, Advisory Committee on Reactor Safeguards subcommittee meeting and the project / Mechanical Engineering Branch meeting of November 22-24, 1982.

Questions regarding the enclosures may be addressed to Mr. R. Spear (FTS 626-6098) of the Project Office Oak Ridge staff.

Sincerely, b.

J kn R. Longene er Acting Director, Office of Breeder Demonstration Projects Office of Nuclear Energy 2 Enclosures cc: Service List l Standard Distribution  !

Licensing Distribution 8301120257 830111 PDR ADOCK 05000537 of)

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~ Enclosure 1 t

Non-destructive Examination of the Steam Generator Steam Generator Shell and Tube-Sheet-To ensureJ the integrity of the water and/or ' sodium boundary -

in the CRBRP steam generator, the following inspections will be performed during fabrication:

a. Pressure boundary welds will be double volumetrically inspected with . a radiographic' examination before Post Weld Heat Treated .(PWHT) and an ultrasonic examination after PWHT in accordance with Code Case 1594-3. The

, surface of-the welds will be inspected either by magnetic particle or liquid penetrant-inspection per the Code,

b. The tubesheets will be ultrasonically inspected 1005'to an acceptance criteria based on a calibration to a 1/2" diameter Flat Bottom' Hole (FBH) and the portion which will be involved in the tube to tubesheet welds will be calibrated to a 1/16" dia. FBH. External machined .

surfaces will be liquid penetrant inspected.

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c. Tube /tubesheet welds are radiographed using the micro-focus rod-anode examination equipment and  ;

penetrant examined on the' exterior surface of the weld zone. The' weld thickness, concavity and convexity are '

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examined ultrasonically and visually.. The welds are also subjected to a Helium leak test both individually i and as a completed module. t The CRBRP program for inservice inspection ~of the steam

• generator shell welds is continuous monitoring leak  :

detection and periodic visual examinations as defined in PSAR Appendix G. The' Project does not consider 3 additional supplementary UT examination of shell welds 1 to be-necessary.

Steam Generator Tubes 4 r

a. During fabrication, the steam generator tubes were 100%

ultrasonically and liquid penetrant examined.

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b. CRBRP steam- generator tube inservice inspection will be by means of ultrasonic scanning of ~ the interior surface

'for detection of wall thinning, corrosion, pitting, or.

other flaws.in.the tube wall along the entire length.

The detectable flaw sizes and wall thinning are as given below:

Wall Thickness -

Wall thinning of greater than .001 in./ year. Measurement of wall thickness shall have repeat precision of no more than A 0.1 millimeters (.004 in.) where precision is defined as three times the standard deviation. Determine if end-of-life tube wall thickness is .077 in. or greater.

Flaws - Flaw sizes equivalent to a 5% notch in the wall or less, a through wall hole of

.005 in. or less, or both.

The wall thickness measurement uses an ultrasonic probe with a rotating beam. The beam is transmitted axially before impinging on a mirror which diverts the beam radially to the tube wall. Tube diameter is determined by beam reflection from the inner surface.

Shear wave ultrasonic techniques are used for the detection of tube wall flaws. The sound pulses are emitted axially onto a reflector which diverts the sound back into the tube wall as an angle beam shear wave. Detected flaws will reflect the sound back to the transducer.

In accordance with PSAR Appendix G, 3% of the tubes in each evaporator /superheater in each module will be examined during the first inspection interval (10 years). During each successive inspection interval, 1-1/2% of the tubes in a module will be inspected.

The following reports provide the status of the CRBRP ultrasonic testing program for the steam generator tubes.

a. Day, R. A. and Kerr, D. S., " Ultrasonic Testing of the Clinch River Breeder Reactor Steam Generator Tubing,"

Materials Evaluation, Vol. 39, January 1981.

b. R. W. McClung, et al, " Techniques for Inservice Inspection of Heat Transfer Tubes in Steam Generators",

Second Joint U.S./ Japan LMFBR Steam Generator Seminar, Conf. - 810615, Rev. 1, Vol. 1, UC-79TK, June 1981.

A final report of UT capabilities from the development program will be forwarded upon completion in December 1983.

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