ML20217B172
| ML20217B172 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 09/09/1997 |
| From: | Buckley B NRC (Affiliation Not Assigned) |
| To: | Langenbach J GENERAL PUBLIC UTILITIES CORP. |
| References | |
| NUDOCS 9709230252 | |
| Download: ML20217B172 (4) | |
Text
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September 9, 1997 Mr. James W. Langenbach Vice President and Director. TMI GPU Nuclear Corporation P.O. Box 480 Middletown PA -17057
SUBJECT:
THREE MILE ISLAND NUCLEAR STATION, UNIT 1 (THI-1) REQUEST FOR ADDITIONAL INFORMATION REGARDING SURVEILLANCE SPECIFICATION FOR ONCE-THROUGH STEAM GENERATOR
Dear Mr. Langenbach:
By submittal dated August 12. 1997, as supplemented August 28, 1997. you requested an amendment to the TMI-1 Technical S)ecifications (TS) to modify the surveillance specifications for once-througl steam generators inservice inspection for THI-1 Cycle 12 refueling outage.
Based on our review of the above cited submittals, we find additional information, as requested in the enclosure, is required in order to continue our review.
If you have anv questions on this matter, please call me at (301) 415-1483.
Sincerely.
Original signed by Bart C. Buckley, Senior Project Manager Project Directorate I-3 Division of Reactor Projects - I/II Office of Nuciear Reactor Regulation Docket No. 50-289
Enclosure:
Request for Additional Information cc w/ encl: See next page
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o Three Mile Island Nuclear Station, Unit No. I cc:
Michael Ross Robert B. Borsum Director, OLM, TMI B&W Nuclear Technologies GPU Nuclear Corporation Suite 525 P.O. Box 480 1700 Rockville Pike Middletown, PA 17057 Rockville, MD 20852 John C. Fornicola William Dornsife Acting Director Director, Planning and Bureau of Radiation Protection i
Regulatory Affairs Pennsylvania Department of GPU Nuclear Corporation Environmental Resources 100 Interpace Parkway P.O. Box 2063 Parsippany, NJ 07054 Harrisburg, PA 17120 Jack S. Wetmore Dr. Judith Johnsrud Manager, THI Regulatory Affairs National Energy Committee GPU Nuclear Corporation Sierra Club P.O. Box 480 433 Orlando Avenue Middletown, PA 17057 State College, PA 16803 Ernest L. Blake, Jr., Esquire Shaw, Pittman, Potts & Trowbridge 2300 N Street, NW.
Washington, DC 20037 Chairman Board of County Commissioners of Dauphin County Dauphin County Courthouse l
Harrisburg, PA 17120 i
Chairman Board of Supervisors of Londonderry Township R.D. #1, Geyers Church Road Middletown, PA 17057 Wayne L. Schmidt Senior Resident Inspector (THI-1)
U.S. Nuclear Regulatory Commission P.O. Box 311 Middletown, PA 17057 Regional Administrator, Region I U.S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA 19406
1*
TMl Amendment No. 288 -- Re==t for Additional information 1.
The proposed amendment would apply only to intergranular attack (IGA) degradation initiating from the inside diameter (ID) of a steam generator tube. This degradation was a consequence of the sodium thiosulphate intrusion in the early 1980's, and the.
licensee has concluded that its growth has arrested. Describe how these indications are tracked from outage to outage, and discuss the provisions included in the data analysis guidelines to ensure that the proposed repair criteria are only applied to those indications dating back to the original thiosulphate intrusion? Explain how new IGA degradation (i.e., not a result of thiosulphate intrusion) will be identified and dispositioned during the course of the tube examinations. Discuss whether new indications will be dispositioned using the proposed voltage / dimensional based limits and whether the tube would be counted in the classification of inspection results per TS 4.19.3.
2, Given the limitations in relying on eddy current phase angle to verify the initiation surface of tube degradation, describe the eddy current data analysis methodology used to distinguish between ID IGA and degradation initiating from the outside diameter of a tube, in addition, provide details on hcw the technique was qualified to make such a characterization.
3.
The proposed changes to TS 4.19.4.3.a include a provision to classify a tube as degraded if the voltage of an ID IGA indication is equal to or exceeds 0.5 volts.
Explain the basis for establishing a 0.5 volt degradation threshold and discuss its relationship to the existing 20 percent depth based threshold.
4.
Has a growth rate study of ID IGA indications been performed considering rotating pancake coil (RPC) data (e.g., voltage, length, width)? If so, provide the results, if not, discuss the usefulness of such a study.
5.
The information provided on the assessment of growth rate for the ID IGA degradation does not appear to address how differences in data acquisition between inspections were considered in the studies. Discuss how changes in the acquisition of eddy current data (e.g., probes, cables, testers, etc.) affcet the voltages of indications j
measured in previous inspections.
6.
The discussion on in situ pressure testing included in the submittal dated
' August 28,1997, states the criteria for tube selection for the upcoming outage. The criteria specify that tubes with the highest bobbin coil voltages coupled with the lowest dimensional extent as measured by RPC and those tubes conta!ning the indications with the highest axial and/or circumferential lengths will be considered for testing. The staff notes that, based on previous experience with in situ pressure testing, tube selection may need to address other quantitative measurements (e.g.,
RPC voltage, phase angle depth measurements) and qualitative aspects (e.g., signal quality) of the eddy current data in order to determine the best candidates for testing.
Discuss whether-such factors will be considered in the tube selection criteria during the upcoming refueling outage. If criteria other than that included in the submittal are not going to be considered for tube selection, discuss the basis for this decision.
ENCLOSURE
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7.
The proposal to use in situ pressure testing to assess the leakage integrity of tubes j
implicitly relies upon the ability of the test to adequately simulate tube losos during
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postulated accident conditions. According to the submittal dated August 28,1997, j
- (t]he in situ preseure test causes a higher principal stress in the circumferential j
direction than that caused by the MSLB load in the axial direction." Although the test j
loading for axlally oriented flaws should be conservative with respect to accident induced loads provided temperature related effects are also considered, the staff j
cannot determine whether the loading for circumferentially oriented defects will also be conservative during the in situ pressure tests. Discuss the cualification of the in situ prowJte test device and its ability to adequately simulate postulated accident tube loads.
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