ML19248A743
| ML19248A743 | |
| Person / Time | |
|---|---|
| Site: | Fermi  |
| Issue date: | 08/11/1981 |
| From: | Tan C Office of Nuclear Reactor Regulation |
| To: | Schauer F Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML19248A744 | List: |
| References | |
| NUDOCS 8108210207 | |
| Download: ML19248A743 (3) | |
Text
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T, DISTRIBUTION AUG 11 1931 Central File SEB Reading File
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P MEMORANDUM FOR:
Franz P. Schauer, Chief
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Structural Engineering Branch
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Divisicn of Engineering 1 I 1331 "' O THRU:
Pao-Tsin Kuo, Section Leader B Structural Engineering Branch
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Division of Engineering V
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Chen P. Tan 4_ i g O Structural Engineering Branch Division of Engineering
SUBJECT:
SUMMARY
OF JULY 21-22, 1981 MEETING REGARDING OPERATING LICENSE REVIEW OF FERMI 2 The purpose of the meeting was to conduct a limited audit of Fermi 2 seismic reassessment of Category I structures. The audit was conducted at Fermi 2 A/E firm. Sargent and Lundy, in Chicago. The two appendicies A 4.1 and A 4.2 to Enrico Fermi Atomic Power Plant Unit 2 Report No. EF 2-53332 were the bases of the audit.
A list of attendees is Enclosed.
The following are the highlights of the audit:
1.
The first item discussed was the combination of responses of structures to three components of earthquake since there is no statement in the FSAR in this respect.
A. K. Singh of S & L stated that the responses of the structures to the two horizontal components were determined using the time history method and inputting simultaneously two statistically independent acceleration time histories. The resultant horizontal component was combined with the vertical component by the SRSS rule. The staff accepts this procedure for combination of responses. The applicant will include the description of such a procedure in a future amendment to the FSAR.
2.
For the reassessment of buried pipes and duct runs, the staff required that the ground particle velocity should be obtained from the acceleration time histories used to generate response spectra to envelop the site-specific response spectra as specified.
S & L computed the ground particle-velocity and found it to be imaller than the 7.2 in/sec. value originally used.
Therefore tt.e original design is still valid. The staff requested that the section on buried pipe should be amended to reflect what was actually dor,e.
CONTACT:
C. P. Tan, SEB, x29468 emerh ums) 8108210207 810911 CF ADOCK 05000341 ran )
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Franz P. Schauer 3.
The staff had a number of concerns on the reassessment of the seismic Category I structures.
However, after discussion with S & L design engineers, the staff had a better understanding of what was done, the rationale behind their conclusion and bases of their acceptance criteria.
Therefore, most of the staff's original concerns were resolved. A large number of hangers for cable tray were originally found to be highly overstressed.
However, by using the actual dead load instead of the assumed the stresses in the hangers with the exception of one hanger have been found to be within the allowable.
The staff had concerns on the high concrete shear stresses in the foundation mat as indicated by the analysis.
By using a more realistic fomula to calculate the allowable shear stresses, the calculated shear stresses are found to be within the allowable.
For the reactor building mat foundation the original capability of the mat to resist the torus uplift of 2000k per support was reduced to 1370k.
It is to be confimed that this reduced torus uplift capacity is larger than that detemined from the Mark I Long Tem Program.
4.
The analysis showed that the calaculated stresses in the main structures were well below yield. Therefore, the staff questioned the appro-priateness of using 7% damping in the structural analysis.
Because of the low stress level, a 5% damping should be used instead.
Even though the final results for structures may not be affected by such a change in damping values, it is believed that such a change may affect the equipment seismic qualification.
The staff expressed this concern to the applicant and his A/E.
On the basis of the results of audit it is concluded that the outstanding issues in structural area have been resolved. This conclusion will be documented in our Supplement 1 to the SER.
Chen P. Tan Structural Engineering Branch Division of Engineering CC:
R. Vollmer J. Knight R. Tedesco B. Youngblood P. Kuo H. Pol k c.oa p DE:SEBgf-[
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OFFICIAL RECORD COPY
LIST OF ATTENDEES N;f STAFF P. T. Kuo H. Poll C. P. Tan DETROIT EDISON PER5DN!?EL Walter M. Street Yogi Anand SATGENT AND LU!;DY PERSONNEL Robert Witt Marty Tatosian A. K. Singh N. V. Hingaain S. Dutta M. Khayyata Dav T. Le C. N. Krishnaswamy