ML20054J482
| ML20054J482 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 06/23/1982 |
| From: | Novak T Office of Nuclear Reactor Regulation |
| To: | Mattimoe J SACRAMENTO MUNICIPAL UTILITY DISTRICT |
| References | |
| TAC-48384, NUDOCS 8206290080 | |
| Download: ML20054J482 (3) | |
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[M] g Docket No. 50-312 ORB #4 Rdg DEisenhut 0 ELD AE0D Mr. J. J. Mattimoe IE Assistant General Manager and ACRS-10 Chief Engineer MPadovan Sacramento Municipal Utility RIngram District Gray File 6201 S Street EBlackwood P. O. Box 15830 H0rnstein Sacranento, California 95813 JKnight WJohnston
Dear Mr. Mattimoe:
TNovak
SUBJECT:
AUXILIARY FEEDWATER HEADER REPAIR - REQUEST FOR ADDITIONAL INFORMATION As a result of the discovery of damage at the Davis-Besse facility, SMUD perforned similar inspections of the once-through steam generator auxiliary feedwater headers at the Rancho Seco facility. The results of the inspections have been reported in Licensee Event Report No. 82-10.
General plans for repair have been discussed in a meeting held between you and the NRC staff on May 19, 1982 and in infomal communications subsequent to that date.
We have reviewed the available infomation regarding your planned repairs and find that additional infomation is required for our reviews. Therefore, pursuant to 10 CFR 50.54(f), we request that you provide us your responses to the following items, no later than 10 days prior to scheduled restart. Your responses must be submitted to the NRC, signed under oath or affirmation, to enable the Commission to deternine whether or not your license shall be modified, suspended, or revoked.
1.
Provide a detailed description of the repairs and modifications to the auxiliary feedwater system. Describe how the as modified systen compares to the auxiliary feedwater design used previously in other operating B&W plants. Compare the expected perfomance of the modified design to that of the original design and of earlier B&W units.
2.
Describe the program to identify and recover icose parts resulting from previous damage and those that may be produced during repair. Describe your loose parts monitoring systen(s) and discuss detection capability partic-ularly with reference to any known or potential loose parts.
If loose parts will exist after operation, evaluate the safety consequences.
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fir. J. J. Mattimoe 3.
Describe the types of pre-repair inspections performed on the steam generator shell, shroud and header and discuss the results. Supply a drawing or drawings which show the limits of each inspection performed.
Identify the criteria used to evaluate the soundness of the header and discuss, where applicable, the ability of the remote visual inspections to detect flaws with respect to the acceptance criteria.
4.
Describe the original criteria for minimum acceptable clearances between the AFU header and supports and the peripheral tubes, and relate this to the clearances that will exist after repairs are completed.
If clearances af ter repair are less than the minimum acceptable for the original design, provide the necessary analyses to justify operation under nomal, transient, and accident conditions.
5.
Discuss your criteria and procedures for plugging and stabilizing of peripheral tubes.
6.
Provide an analysis which demonstrates acceptable results when maximum expected forces are applied to the stabilized header considerina normal, transient, and accident conditions.
7.
Describe your acceptance criteria for all welds used to stabilize or reinforce the header. Describe in detail the inspection program to be followed.
8.
What inspections will be performed following the stabilization of the header to ensure that distortion from welding does not reduce clearances between tubes and the header below the minimum acceptable?
9.
Provide an analysis of AFW flow induced tube vibration for the modified AFW design.
- 10. Describe your plans for revision of the ISI/IST program to include steam generator internals on the steam side.
- 11. Describe the post-repair startup test and inspection program, including water hanner tests, to be conducted prior to the resumption of power qperations.
Since your proposed repairs include changes in the facility, which involve an un-reviewed safety question, f1RC approval will be required prior to facility operation.
The reporting requirenents contained in this letter affect fewer than ten respondents; therefore, O!!B clearance is not required under P.L. 96-sil.
Sincerely,
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Thomas it, Novak, Assistant Director OKLN' for Operating Reactors
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Present, in detail, the types of pre-repair inspections performed on the stean generator shell, shroud and header and discuss the results. Supply a drawing or drawings which show the limits of each inspection performed.
Identify the criteria used to evaluate the soundness of the header and discuss, where applicable, the ability of the renote visual inspections to detect flaws with respect to the acceptance criteria.
4.
Provide the original mininum acceptable clearances between the AFW header and supports and the peripheral tubes and relate this to the clearances that will exist after repairs are completed.
If clearances af ter repair are less than the minimun acceptable for the original design, provide the necessary analyses to justify operation under nornal, transient, and accident conditions.
5.
Discuss your plans for plugging and stabilizing of peripheral tubes including details of how any tube stabilization will be accomplished.
6.
Provide an analysis of the naximum forces on the stabilized header considering normal, transient, and accident conditions.
7.
Describe your acceptance criteria for all welds used to stabilize or reinforce the header. Describe in detail the inspection program to be followed.
8.
What inspections will be perfon.<ed following the stabilization of the header to ensure that clearances between tubes and the headcr have not been reduced below the minicun acceptable due additional distortation from welding.
9.
Provide an analysis of AFW flo.< induced tube vibration for the nodified AFU design.
- 10. Describe your plans for revision of the ISI/IST progran to include steam generator internals on the stean side.
- 11. Describe your plans for conducting water hamer tests on the nodified AFW systen.
The reporting requirenents contained in this letter affect fewer than ten respondents; therefore, Oi!B cicarance is not required under P.L.96-511.
Sincerely, Darrell G. Eisenhut, Director Division of Licensing cc: See next page g%
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