ML19350C766

Amended & Addl Responses to NRC 801126 Interrogatories Re Plant Fill & Stress Induced in Structure Due to Settlement. Affidavits & Certificate of Svc Encl

ML19350C766
Person / Time
Site:	Midland
Issue date:	03/20/1981
From:	Ohar B, Swanberg N CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:	NRC OFFICE OF THE EXECUTIVE LEGAL DIRECTOR (OELD)
References
ISSUANCES-OL, ISSUANCES-OM, NUDOCS 8104060674
Download: ML19350C766 (14)

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f ?s" APR0 AMENDED AND ADDITIONiL RT.SPONSES TO h u.s, % 8 0 I b bII CERTAIN NRC STAFF INTERROCATORIES DATED 11/26/80 9( codd@% N Interrogatorv 4 k

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In the respouse to Question 15 of the NRC request, regarding plant fill, it is stated that, " differential settlement primarily induces additional strain, which p is a self-limiting effect and does not affect the ultimate strength of the structural m__.bers." Additional clarification of this statement is needed.

4(a) 'n'hy do you classify the resulting strains as self-li=1 ting in nature?

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Resnons e The term "self-limiting" is a shorthand expression for the behavior of a structure under strain-induced loads such as settlement in the absence of a bearing capacity failura.

Based on the charai:teristics of supporting soils and the imposed load from a l

structure, the predicted settlement of the scheture can be calculated over its its lifetime. To evaluate the effect of settlement on the structure, the settlement can be divided into the following:

(1) Uniform settlement (rigid body translationi m

(2) Dif ferential settlement (a) Tilting (rigid body rotation)

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(b) Curvature 9 Sof 6'I

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l Rigid body notion of the structure, both translation and rotation, does act cause any strain in the structure. Therefore, it is of no concern in the evaluation of structural adequacy.

i In contrast, curvature in the structure due to settlement vill cause additional strain in the structure.

Therefore, the effects of curvature induced due to settlenent need to be

investigated.

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Curvature and Stress -

When a structural element is subjected to curvature (6), tensile strain is induced in the convex side and cc=pressive strain in the concave side of the element (Figure 1) . For a concrete structural element, the

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theoretical relationship between curvature and =cment can be established based on the stress-strain relationship of concrete and reinforcing steel.

An idealired moment-curvature plot of an under-reinforced concrete section similar to those used in the Midland Diesel Generator Building is shcun l in Figure 2. As can be seen frem Figure 2, the curvature increases linearly as the moment is increased, up to the moment My, corresponding to the poinc ,

j of yielding for' thedensile steell ~ Beyond that point, any increase in t

l curvature would not increase the moment in the structural element. The

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mari== curvature that can be induced in the element' is Ou, corresponding to an ultimate concrete strain of.003.

Behavior of Structures sue $ected to Loads l

The loads applied on a structure can be divided into two categories:

(1) Externally applied forces i '

(2)' Externally applied strains l

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When structures are subjected to externally applied forces, internal forces and sc=ents =ust be induced in the structure to re.:. core static equilibrium between external and internal forces. An increase in curvature beyond 9y* is not useful in resisting such external forces, I

as no additional internal moment is mobilized due to the additional curvature.

When an externally applied strain due to settlement is applied to a l

l structure, the structure must be capable of accommodating additional l

strain imposed on it without failure. Since no net external forces are applied by that process, the induc,ed strain need not cause internal forces in the I

structure.

Therefore, even if a structure has already reached 6 7due to an externally applied force, the structure can still resist externally I More-l applied strain so long as the resultant curvature is less than 9u.

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over, the behavior of the structure vould be the same regardless of which influence- the settlement strain or the external force -is applied first.

' For example, let "Mg" be the moment induced in the structure due to ,

- external forces and A9 be the additional curvature induced due to settlement. In the elastic range, let AM be the increase in moment due to 6 8. If-(M 4 + 0M) is less than My, the additional curvature due to curvature settlement will cause the additional moment corresponding to t (A6). (risure 3)

On the other hand if (M

+ A X) is greater than My as in (Figure 4), the i

structure will see a moment equal to My with an increase in curvature equal  ;

I to 0 9. The increase in moment due to curvature in this instance (i.e.

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Figure 4) is less than it would be were the yield =cuent high

,enough such that M +A M < My. If M = My, there is no increase in menent. Since A M is not required to restore static balance, the structure vill be stable even iffM = 0, as long as the additional curvature A0 does not result in a curvature of the structure greater than Ou.

Conclusion The stress induced in a structure due to settlenent can vary from raro to a maximum of a proportionality constant

• multiplied by the induced curvature. The actual stress is assigned by the structure itself depe:x!1ng on its capacity to resist stress af ter allowing for any stress

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requirements due to external forces.

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5-4(b) How do you reconcile your statenent quoted above with your statement concerning the Service Water Pump Structure in the . Management Corrective Action Report No. 24, Interim Report 6, issued September 7, 1978 that the total design loads cannot be supported'by the =ain structure.

Response

For purposes of the underpinning design of the foundations of the service water pump structure, no credit was taken for any bearing capacity in the fill material. Under these circumstances the self-limiting analysis described in the Response to Interrogatory 4(a) does not apply, since the mechadism for producing possible strains in the structure is not limited to settlement.

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Interrogator r 1(e) and 1(f) (Amended Resoonses) 1(e) Have you factored into any re-analysis infor=atic n cer.tained in, or resulting from, a letter frem Robert Tedesco to Vice President J. Cook dated October 14, 1980, concerning seismological input data acceptable to the Staff?- ,

Response

Applicant objects on the ground that this questien goes beycud the limited jurisdiction conferred by the December 6,1979 Order, that the seismic re-analysis requested by Mr. Tedesco in the October 14, 1980 letter should be reserved for the operating license hearing, and, hence, that it is irrevelant to these proceedings. Subject to that-objection, Applicant answers as follows: The pending seismic re-analy-sis requested in the October 14, 1980 Tedesco letter has been considered in arriving at the folleving approach towards designing and analyting the remedial fixes for the auxiliary building electrical penetration area, the service water pump structure, and the berated water storage tank ring foundation: Seismic forces obtained by application of FSAR input criteria (i.e. modified Housner spectra and maximum acceleration "

, anchored at .12 g) vill be increased by a reasonable margin. Forces

, thus determined will be combined with other loads in accordance with-applicable lead combinations in arriving at design parameters for the remedial measures. In addition, with respect to the Diesel Generator Building, Bechtel is attempting to evaluate the total margin which actually exists in excess of FSAR seismic design criteria.

When discussions with the NRC Staff respecting possible redefinition of seismic criteria applicable to the entire Midland site are completed, Applicant vill evaluate the necessity for seismic re-analyses of any or all Category I Structures, including those founded partly or entirely on plant fill.

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1(f) If the answer (e) is yes, please provide copies of all docu=ents relating to that re-analysis.

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Response -

The decu=ents pertaining to the design analyses of the renedial fixes for the service water pu=p structure, the auxiliary building and the borated water storage tank ring foundatica (using the apprcach spelled out in the respense to 1(e)) vill be provided, as stated in the respense to questien (b). Applicant objects to providing documents relating to the analysis of total =argin in excess of FSAR seis=ic design criteria fer the Diesel Generater 3u11 ding, for the reasons ' stated in 'the first sentence of Applicant's respcase to questics 1(e). For the sane reason, Applicant objects to providing in this proceeding future seismic re-analyses of

. . Midland structures as requested by the October 1!.. 1980 Tedesco letter.

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- UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION g

. BEFORE THE ATOMIC SAFETY AND LICENSING 30ARD j

. ~- f' In the Matter of )

CONSUMERS POWER COMPANY ) . Docket Nos. 50-329-0M

) 50-330-0M j 50-329-OL  ;

(Midland, Units 1 and 2) )

50-329-OL  ;

)

COUNTY OF WASHTENAW)

)ss STATE OF MICHICAN )

AFFIDAVIT OF BIMAL LEAR  :

1 Bimal Dhar, being duly sworn, deposes and says that he is e= ployed by Bechtel Associates Professional Corporation,'as an Engineering Supervisor; that he is responsible for providing an answer to Censumers Power Company's Answer to E C Staff Inter ogatery No. 4 dated 11/2e/e0, and that to the ,

best of his knowledge and belief the above infornation and the answer to l

the above Interrogatory is true and correct.

pimalDhar Subscribed and sworn to before me this / .3 day of March, 1981.

et J. ' 6 /L.w Notary Public Washtenaw County, Michigan My Co= mission Expires: N.A I+vU_ 4/[(

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UNITED STATES OF AMERICA NUCLEAR REGtH ATORY COMMISSION BEFORE THE ATOMIC SAFETY AND LICENSING BOARD In the Matter of ) DOCFIT NOS. 50-329-0M CONSUMERS POWER COMPANY ) 50-330-0M

) 50-329-OL (Midland, Units 1 and 2) ) 50-329-OL

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COUNTT OF WASHTENAW)

)ss STATE OF MICHIGAN )

AFFIDAVIT OF NEAL SWANBERG Neal Swanberg, being duly sworn, deposes and says that he is enployed by Bechtel Associates Professional Corporation, as an Assistant Project Engineer; that he is responsible for providing amended responses to NRC Staff Interrogatories to Consumers Power Company Numbers 1(e) and (f) and that to the best of his knowledge and belief the above infor-mation and the answers to the above interrogatories are true and correct. ,

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l Neal Swanberg' /

l Subscribed and sworn to before me this / day of M _ri I , 1981.

._, . h.. LA u Notary Public, Washtenaw County, Michigan My Commission Expires: %%e, _ it.f.2/ / ///4 2I 2-~.? A. 5 00~ i

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UNITED STATES OF AMERICA

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.7 ny . g 4 j g g j p ,1-NUCLEAR REGULATORY COMMISSION Ci".ca of tM Set ets' 0;;... 9; & Seni:t ,

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In the Matter of )  % ,

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) Docket Nos. ~

CONSUMERS POWER COMPANY )

3 0 (Midland Plants, Units 1 and 2 2

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CERTIFICATE OF SERVICE I hereby certify that copies of Amended and Additional Respenses to Certain NRC Staff Interrogatories Dated 11/25/80, with attached affidavits, were served upon the following persons by depositing copies thereof in the United States Mail, first class postage on this 20th day of March, 1981.

Frank J. Kelley, Esq. Michael Miller, Esq.

Attorney General of the Isham, Lincoln & Beale State of Michigan One First National Plaza Stewart H. Freeman, Esq. Suite 4200 Assistant Attorney General Chicago, Illinois 60603 ,

l Gregory T. Taylor, Esq.

Assistant Attorney General Mr. Steve Gadler 720 Law Building 2120 Carter Avenue Lansing, Michigan 48913 St. Paul, Minnesota 55108 Myron M. Cherry, Esq. D. F. Judd, Sr. Proj ect Manager One IBM Plaza Babcock & Wilcox Suite 4501 P. O. Box 1260 Chicago, Illinois 60611 Lynchburg, Virginia 24505 Mr. Wendell H. Marshall Atomic Safety & Licensing Appeal Board RFD 10 U. S. Nuclear Regulatory Comission i

Midland, Michigan 48640 Washington, D. C. 20555 i

Charles Bechhoefer, Esq. Mr. C. R. Stephens, Chief Atomic Safety & Licensing Board Panel Docketing & Service Section l U.S. Nuclear Regulatory Comm. Office of the Secretary i

U. S. Nuclear Regulatory Commission Dr. Frederick P. Cowan Washington, D. C. 20555 6152 NJ Verde Trail Apt..B-125 Boca Raton, Florida 33433

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Lester Kornblith, Jr.

Atomic Safety & Licensing Board '

U. S. Nuclear Regulatory Comissica . ,

Washington, D. C. 20555 Ralph S. Decker, Esq.

Route 4 Box 1900 Cambridge, Maryland 21613 Ms. Mary Sinclair 5711 Summerset Street Midland, Michigan 48640 William D. Paton, Esq.

Counsel for the NRC Staff U. S. Nuclear Regulatory Commission Washington, D. C. 20555 Atomic Safety & Licensing Board Panel-U. S. Nuclear Regulatory Comission Washington, D. C. 20555 Barbara Stamiris 5795 North River Road Route 3 Freeland, Michigan 48623 .

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James E. Brunner Consumers Power Company 212 West Michigan Avenue Jackson, Michigan 49201 ,

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