ML20093C073

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Summarizes Technical Comments from ACRS Subcommittee 820429 Meeting Re Remedial Activities for Deficient Soils
ML20093C073
Person / Time
Site: Midland
Issue date: 05/04/1982
From: Adensam E
Office of Nuclear Reactor Regulation
To: Bosnak R
NRC
Shared Package
ML19258A087 List: ... further results
References
CON-BX18-035, CON-BX18-35, FOIA-84-96 NUDOCS 8205120033
Download: ML20093C073 (4)
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MAY 4 1982 I

j NOTE TO:

R. Bosnak j

G. Lear i

F. Schauer R. Jackson FROM::

Elinor G. Adensam, Chief Licensing Branch #4, DL 1

SUBJECT:

TECHNICAL COMMENTS FROM.ACRS SUBCOMMITTEE MEETING OF APRIL 29, 1982 ON MIDLAND S0ILS e

At the ACRS Subcommittee meeting on April 29, 1982, regarding remedial activities for the deficient-soils at the Midland Plant, several technical comments were made by the Subcommittee which appear to warrant further consideration during our technical review. A few of these comments are listed below:

l 1.

The day tanks within the Diesel Generator Building (DGB) are located on the second floor level and feed the diesels mounted on pedestals independent of the DGB itsel f.

What is the effect of past and future differential settlements to the lines from these day tanks? What margin is available?

How much of the margin is associated with seismic forces?

2.

A probabilistic argument could be made that structural failure during earthquakes is notj itself, a major contributor to probability of failure of the safety function of the housed equipment.

3.

The applicant's explanation why that segment of the BWST lines from the tank farm dike to the Auxiliary Building should not also be rebedded was not technically convincing. The fact that a part of the line is sleeved does not eliminate differential settlement stresses in unsleeved portions.

4.

Concerning the BWST foundations, the Subcommittee appeared to be skeptical about the use of dowels to transfer the loads from the existing ring foundation into the new adjacent ring beam. One member suggested a load distribution plate at the top of the composite ring would be advantageous.

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Dr. Siess made a strong recommendation that settlement monitoring of the i

BWST foundations over life be performed, and that differential movement of the tank itself be checked during life. This should be in addition to present strain measurement plans.

6.

The Subcommittee felt that rattlespace monitoring at piping penetrations should be measured for life. They expressed curiosity why the applicant would not elect to monitor such straight forward and simple performance indications.

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We were alerted that the Full Comittee will have interest in seismic j

margin criteria and may not fully agree with the staff that the SSRS is sufficiently conservative.

The above comments are reconstructed from notes made during the meeting,

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and are not a complete listing of significant feedback. The transcript should be available shortly, and is recommended for your further review.

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Elinor G. Adensam, Chief i

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R. Tedesco J. Knight D. Hood R. Hernan I

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SUCJECT: TECHMICAL C0".'iENTS FRO'l ACRS SUBCOWIITTEE MEETING OF APRIL 29, 1982 O!! MIDLAND SOILS t

i At the ACRS Subcomittee meeting on April 29, 1982, regarding remedial activities for the deficient-soils at the Midland Plant, several technical coments were made by the 'Subconnittee which appear to warrant further consideration during our technical review. A few of these co rents are listed below:

1.

The day tanks within the Diesel Generator Building (DGB) are located on the second floor level and feed the diesels nounted on pedestals independent of the PG9 itself. What is the effect of past and future differential settlerents to the lines fro 1 these day tanks? What cargin is available?

F.ow nuch of the cargin is associated with seismic forces?

2.

A crcbabilistic argument could be rade that structural failure during earthquakes is not itself, a najor contributor to probability of failure of the safety function of the housed equipnent.

3.

The applicant's ex)lanation why that segment of the BWST lines from the tank fara dike to the Auxiliary Building should not also be rebedded was not technically convincing. The fact that a part of the line is' sleeved does not eliminate differential settlement stresses in unsleeved portions.

4.

Concerning the BWST foundations, the Subcommittee appeared to be skeptical

' about the use of dowels to transfer the loads fron the existing ring foundation into the new adjacent ring bean. One member suggested a load distribution olate at the too of the composite ring would be advantaceous.

S.

Dr. Siess r:ade a strong recomendation that settlerent monitoring of the BNST foundations over life be perfor ed, and that differential movement of the tank itself be checked during life. This should be in addition to cresent strain measurenent plans.

6.

The S,ubcomittee felt that rattlespace nonitorino at piping penetrations should be measured for life. They expressed curiosity why the applicant would not elect to monitor such straight forward and sinple perfornar.ce indications.

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Ve ucra alerted that the Full Comittee will have interest in seismic 4

margin criteria and may not fully agree with the staff that the SSRS i

is sufficiently conservative.

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j The above coments are reconstructed from notes r.ade during the meeting' and are not a Conplete listing of significant feedback. The transcript should be available shortly, and is recommended.for your further review.

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Elinor G. Adensaa, Chief Licensing Branch #4 Division of Licensing cc:

.R. Tedesco J. Knight D. Hood R. Hernan t

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