ML19289F444
| ML19289F444 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 04/24/1979 |
| From: | Gilleland J TENNESSEE VALLEY AUTHORITY |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| NUDOCS 7906070378 | |
| Download: ML19289F444 (3) | |
Text
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TENNESSEE VALLEY AbYHORITY Sb'M gde CH ATTANOOGA. TENNESSEE 374o1 500C. Chestnut Street Tower II IS AFil2G n g: 15
_APR 2 4 1979 Mr. James P. O'Reilly, Director Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Region II - Suite 3100 101 Marietta Street Atlanta, Georgia 30303
Dear Mr. O'Reilly:
OFFICE OF INSPECTION AND ENFORCEMENT BULLETIN 79 RII:JP0 50-259, 260, -296 - BRORNS FERRY NUCLEAR PLANT UNITS 1, 2, AND 3 In response to your April 14, 1979, letter which transmitted IE Bulletin 79-07, we are enclosing the results of our investigations at Browns Ferry Very truly yours, J. E. Gilleland Assistant Manager of Power Enclosure cc: Office of Inspection and Enforcement (Enclosure)
Division of Reactor Operations Inspection U.S. Nuclear Regulatory Commission Washington, DC 20555 2231 350 79060703W r80p 0 0
prr1CIAL C010 An Equal Opportunity Employer
d RESPONSE TO IE BULLETIN 79-07 DATED APRIL 14, 1979, FOR BROWNS FERRY NUCLEAR PLANT SEISMIC STRESS ANALYSIS OF SAFETY-RELATED PIPING Item 1 Identify which, if any, of the methods specified below were employed or were used in computer codes.for the seismic analysis of safety related J
piping in your plant ard provide a list of safety sys. ems (or portions thereof) affected:
Response Spectrum Model Analysis:
Algebraic (considering signs) summation of the codirectional spatial a.
component.- (f.e., algebraic summation of the maximum values of the co-directional responses caused by each of the components of earthquake motion at a particular point in the mathematical model).
4 b.
Algebraic (considering signs) summation of the codirectional inter model responses (i.e., for the number of e-des considered, the maximum values of response for each mode surmed algebraically).
Time History Analysis:
Algebraic summation of the codirectional maximum or the time a.
dependent responses due to each of the components of earthquake motion action simultaneously when the earthquake directional motions are not statistically independent.
Response to Item 1 TVA has thoroughly investigated all non-NSSS systems and has found that no analysis was performed using the Response Spectrum Model Analysis or Time liistory Analysis.
General Electric (GE) has thoroughly investigated all safety-related NSSS systems (recirculation piping and steam piping) and has found that no analysis was performed using the Response Spectrum Model Analysis or Time History Analysis. The subvendor under GE for the feedwater system piping has stated that based upon their review to date, none of the methods identified above were utilized in their computer codes.
J s Item 2 Provide complete computer program listings for the dynamic response analysis portions for the codes shich employed the techniques, identified in item 1 above.
Response to Item 2 As noted in the response to Item 1, TVA or General Electric used neither of the questioned analysis methods.
I t em 3 Verify that all piping computer programs were checked against either piping benchmark problems or compared to other piping computer programs. You are requested to identify the benchmark problems and/or the computer programs that were used for FMCh verifications or describe in detail how it was determined that these p;ograms yielded appropriate results (i.e.,
gave results which corresponda 3 to the correct performance of their intended methodology).
Response to Item 3 The computer code PISOLIA owned by EDS Nuclear Corporation was used to check the non-NSSS analysis. Sequoyah FSAR section 3.9.2.5.3 references this program and gives a further description with methods of verification.
The response to this item for the NSSS systems provided by GE are being prepared by the subvendors that performed those analyses. This response will be submitted to NRC as soon as the subvendor makes it available to TVA.
Item 4 If any of the methods listed in item 1 are identified, submit a plan of action and an estimated schedule for the re-evaluation of the safety related piping, supports, and equipment af fected by these analysis techniques. Also provide an estimate of the degree to which the capability of the plant to safely withstand a seismic event in the interim is impacted.
Response to Item 4 This question is not applicable !as a result of responses to Item 1 and 2.
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