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MEMORANDUM FOR: James P. Knight, Assistant Director for Components and Structures Engineering Division of Engineering FROM:
Pao-Tsin Kuo, Section Leader Structural Engineering Section B Structural and Geotechnical Engineering Branch Division of Engineering, ONRR
SUBJECT:
REPORT ON THE REVIEW 0F THE DIESEL GENERATOR BUILDING AT MIDLAND
References:
1.
Memo from R. F. Wanick, Region III to D. G. Eisenhut NRR/DE, " Evaluation of Dr. Landsman's Concerns Regarding the Diesel Generator Building at Midland," dated July 21, 1983.
2.
Memo from R. H. Vollmer, DE to D. G. Eisenhut, DL
" Evaluation of Dr. Landsman's Concerns Regarding Diesel Generator Building at Midland," dated July 21, 1983.
Pursuant to Reference 2 above, a task group, consisting of three members of the Structural Engineering staff and a consultant team of Brookhaven National Laboratory, was famed to re-evaluate the structural design and construction adequacy of the Midland Diesel Generator Building (DGB).
The group, heaaed by P. T. Kuo, reviewed the design review documents and the construction reports; physically inspected the building; interviewed concerned individuals, including Dr. Landsman; and prepared a final report on the adequacy of the Midland NPP Diesel Generator Building.
The final report on the adequacy of the Midland DGB is enclosed.
The task group's conclusions and recommendations are summarized as follows:
1.
The r,ettlement data indicate that the fill under the DGB is well into the secondary consolidation phase so that large additional settlements are not anticipated; 2.
It is iudged that there is reasonable assurance that the structural integrity of the DGB will be maintained and its functional requirement
. ful filled. However, it is difficult to show that the stresses in the DGB can meet the criteria of the FSAR. The stresses due to settlement were either underestimated or overestimated by the Applicant's previous analyses; g g6 g 97 840517 g, g 3 g g g RICE 84-96 PDR
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James P. Knight 4 3.
The most reasonable estimate of stresses due to settlement is based on the crack width data. However, the calculations that have been done in this area need to be completely documented; 4.
There is evidence that the number of cracks in the DGB is continuing to grow.
It is essential that a more accurate and reliable crac!:
monitoring program be established; and 5.
The monitoring program should specify an upset crack width level that would reflect a sufficient stress margin available to resist critical load combinations. The monitoring program should mandate structural repairs if the Alert Limit (in crack width) were exceeded.
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w w-o-Tsin Kuo, Section Leader tructural Engineering Section B Structural and Geotechnical Engineering Branch Division of Engineering
Enclosure:
As stated cc:
H. Denton D. Eisenhut R. Vollmer G. Lear E. Adensam D. Hood N. Romney C. Tan R. Landsman, R III F. Rinaldi J. Kans l
l CONTACTS:
C. P. Tan, SGEB x28424 N. D. Romney, SGEB x28987 l
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