ML20134L261

Forwards Request for Addl Info Re Review of Masonry Wall Design (IE Bulletin 80-11) Submitted w/840229 Ltr.Info Requested within 30 Days of Ltr Receipt

ML20134L261
Person / Time
Site:	Crystal River
Issue date:	08/26/1985
From:	Stolz J Office of Nuclear Reactor Regulation
To:	Wilgus W FLORIDA POWER CORP.
References
IEB-80-11, NUDOCS 8509030165
Download: ML20134L261 (6)

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• August 25, 1985 Docket No. 50-302 DISTRIBUTION (DecRet File?

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• ACRS-10 NRC PDR RIngram L PDR HSilver Mr. Walter S. Wilgus ORB #4 Rdg BMozafari Vice President, Nuclear Operations HThompson Gray File Florida Power Corporation OELD EBrach ATTN: Manager, Nuclear Licensing EJordan H0rnstein

& Fuel Management BGrimes WPaulson P. O. Box 14042; M.A.C. H-3 JPartlow GEdison St. Petersburg, Florida 33733 CTrammel

Dear Mr. Wilgus:

We have reviewed the information on masonry wall design (IE Bulletin 80-11) for Crystal River Unit 3 submitted with your letter dated February 29, 1984, and find that additional information is still needed in order to complete our review of this matter. The requested information is contained in the enclosure.

Please provide.the information requested within 30 days of receipt of this letter.

Sincerely,

%u aus w.a .,a Jow J. sivtJ.'

John F. Stolz, Chief Operating Reactors Branch #4 Division of Licensing

Enclosure:

As Stated cc w/ enclosure:

See next page ORBN:DL ORB . 'm4:DL HSilver;cr JStolz 8@5 8/n /85 8509030165 850826 PDR ADOCM 05000302 G PDR

REQUEST FOR ADDITIONAL INFORMATION MASONRY WALL DESIGN, IE BULLETIN 80-11 '

CRYSTAL RIVER UNIT 3 , -

DOCKET NO. 50-302

- STRUCTURAL AND GE0 TECHNICAL ENGINEERING BRANCH STRUCTURAL ENGINEERING SECTION A 1.

According to Section 1.2.3 of Reference 1, a portion of wall I has been removed to eliminate the wall's possible effect on safety-related equipment (see Figure 4. Ref.1). Explain how this modification removes the safety concern of wall collapse on equipment near wall 1.

2. According to Reference 1, walls 2 and 3 exceed ACI 531-79 alloweble stresses by 50% to 60*; however, according to the cover 4 letter of Reference 1, a recent inspection has shown that the collapse of walls 2 and 3 would not have an adverse effect on safety-related equipment in the area. Indicate the recent findings that have permited these walls to be considered differently and 3inasthe than original eval'uation (Reference 2), which presented wall 2 safety-related. Also, provide the documentation of the evaluation of these walls that, according to the cover letter of Reference 1, was dut by April 30, 1984 but has not yet been provided.

3.

The response to Item 4 in Reference 1 indicates that for the five control ccmplex walls, a " fixed" boundary condition is assumed for nortared joints at masonry wall bases, top edges along a support slab, andwall.

masonry side edges where'the corner is integral with another No dcwels, anchcrs, or other boundary reinforcements are present. Provide the justification for the assumption typical connectionof fixed in ccnditions detail. for mortared joints by examining a on calculated results. Indicate the effect of joint flexibility 4

With respect to Section 3.1.2 of Reference 1, walls 1, 4, and 5 do not meet the ACI minimum requirements for 3hickness, so the ACI 531-79 formula, Fa = 0.255 f'm [1 - (h/4C4 ], for allowable axial ccmpressicn becomes negative.

the Southern Standard Building Code (SSBC) compression stressThese allowable of 70 psi. Also, fixed side boundary conditions in walls 4 and 5 were relaxed to allow for a redistribution of moment, which helped to keep stresses within allowable limits.

the reasons for accepting these walls as meeting the SGEC criteria, Provide s

5.

With respect to the seismic analysis of the instrument room walls in the turbine buildir.g, Section 3.2 in Reference I indicates that the effect of the first nede of vibration was increased by 5" to account for higher modes. Indicate why these walls were not checked control with an eight mode analysis as were the five walls in the complex. i Indicate whether there are other differences in

the criteria between the control complex walls and the instrument reem walls. Also, Figures 22 and 23 show " knife edge" boundary conditions for walls in the turbine building. Indicate whether these conditions were changed to " fixed" or " free" as in the control complex walls, and specify the physical boundary connections.

The staff cces not accept the use of arching or wedging action at boundary c'onnections in qualifying masonry walls (the staff position is attached).

REFERENCES

1. G.R. Westafer Letter

Subject:

with Attachment to J. R. Stolz (NRC)

Crystal River Unit 3 IE Bulletin 80-11, Request for Additional Information . '

Florida Power Corporation 29-Feb-84 .

2. P. Y. Baynard Letter to J. P. O'Reilly (NRC)

Subject:

Crystal River Unit 3, IE Bulletin 80-11, Masonry Wall Design Florida Power Corporation 17-Nov-80 6

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ATTACNENT

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SGEB Staff Position on Use of Arching Action Theory to Qualify Unreinforced Masonry Walls 1 ,

in Nuclear Power Plants a

INTP.00UCTION -

Unreinforced hollow block masonry walls have a very limited capacity under the action of out-of plane loads. Higher resistance could be i) -

ifeVeToped by' c9 eating large in-plane efamping forces 'thereby for61ng a ,

three hinged arch mechanism after mid-span and support flexural cracking j has occurred. The most important conditions'for the arching mechanism to develop are the existence of rotational restraint at the boundaries  !

and the prevention of gross sliding of the wall at support sections.  !

1 Some of the licensees have relied on the development of this arching .

j mechanism (referred to herein as ' arching action theory') to qualify i

unreinforced masonry walls in their plants.

The staff and their consultants have reviewed the basis provided by licensees to justify the use of arching action theory to qualify the ,

unreinforced masonry walls. The staff met with a group of licensees i .,

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representing approximately eleven utilities and twenty two units on I I

Novemoer 3,1982 and January 20, 1983 to discuss this issue. Further, a ,

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site visit and detailed review'of design calculations were conduc'ted by the staff and consultants to gain first-hand knowledge of field conditions and the application of arching action theory in qualifying in-place masonry walls. Based on the information gained through the above activities, the staff has formulated the following position on the

, acceptability of the use of arching action theo,ry to qualify unreinforced masonry walls in operating nuclear power plants. The staff's technical basis for the position is discussed in the attached repor't. .

i POSITION The use of a'rching action theory to qualify unreinforced masonry block '

walls is not acceptable. Therefore, the licensee shall fix the walls

. currently qualified by the use of arching action theory such that they meet the staff acceptance criteria based on the working stress approach.

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/ EVAI,UATION OF AEEING TEEORY IN UNREINFCEED MASONRY MAILS IN NUCLEAR POWER PLANTS 9

Prepared by

• Ahmed A. Bamid Barry G. Barris Vu Con e

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1. Department of Civil Engineering, Drexel University

2. Nuclear Engineering Department, Franklin Research Center

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In, response to IE Bulletin 80- M , a total of 16 nuclear power plants have indicated that the arching action technique has been employed to qualify some unreinforced masonry walls. Based on the review of submittals provided by the

licensees and published literature, Franklin Research Center (FE) staff and FRC consultants have concluded that the available data in the literature do not give enough insight for understanding the mechanics and performance of l unreinforced ansonry walls under cyclic, fully reversed dynamic loading. As a j

i result, a meeting with representatives of the affected plants was held.at the

NBC on November 3,1982 so that the NBC, FRC staff, and FRC consultants could I

explain why the applicability of arching theory to masonry walls in nuclear

{ power plants is questionable [1]. In a subsequent meeting on January 20, i

1983, consultants of utility companies presented their rebuttals (2] and

! requested that they should be treated on a plant-by-plant basis. In accordance with their requests, the NBC staff has started the process of I evaluating each plant on an individual basis. In this process, the NBC, FPC l

staff, and consultants have initiated visits to various nuclear plants to j

examine the field conditions of unreinforced masonry walls in the plants and to gain first-hand knowledge on how the arching theory is applied to actual walls.

Key calculations have been reviewed with regard to the arching theory.

1 EVALUATION OF AERING TEZCar 4

Test of unreinforced concrete masonry walls were recently conducted by Agbabian Associates, S. B. Barnes and Associates, and Kariotis and Associates l [3] (this joint venture work is designated as ARK) . Based on the visit to

! Oconee Nuclear Station, the results of the AEK tests, and all relevant A

information submitted by the licensees including the rebuttals given by the licensees in the January 20, 1983 meeting, the NE, FE staff, and consultants

! have made the following evaluations:

1 j 1. The design methodology used at various nbclear plants was developed 1

by McDowell et al. [4] in 1956 for solid brick walls under static j sonotonic loading. No test data are available to check the adequacy of hollow block ansonry under cyclic, fully reversed dynamic loading.

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n e only dynamic test data for arched masonry wa n s are the URS tests

{ 15] for blast loading. This type of loading is noti a true represen-N tation of earthquake loading because it is not fully reversed and has ,

a decayed nature. Under very short-duration blast loaoing, masonry walls, which have auch lower natural frequencies, would not fully respond to the applied load. In addition, only two wans were tested

{ under cyclic blast loading at URS for arched masonry wan s.

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Extrapolation is questionable.

of test data from solid masonry to hollow block ansonry i

Recent test data [6] of eccentricany loaded ansonry assemblages showed that the failure mechanism, strain ,

j distribution, and overan behavior of honow ansonry are quite different from those of solid or grouted masonry.

4. Ec uow block masonry walls are more susceptible to premature j

i wet >-shear failure or crushing compression failure. Precluding these types of failure is neccesary for the development of the arching mechanism. No data are available at the present time to determine the safety factors against these brittle failures under seismic l loading.

5.

i ascent ARK dymanic tests [3] showed that unreinforced block masonry j walls did fail (conapse) under earthquake loads with ground i

acceleration (effective peak acceleration) of about 0.3g to 0.4g, which is typical for nuclear plants. Also, some wan s experienced

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local crushing at the base before failure by instability, which emphasizes walls.

the possibility of premature compression failure of arched i

It must be noted, however, that the AEK test wans were not j restrained at top to develop arching. The effect of boundary conditions could be significant and cannot be evaluated without further testing. l 4

6.

' Unreinforced block masonry walls are extremely brittle, and flexural j

failure occurs without warning. The sensitivity of unreinforced i evident. toAlso, aasonry crack development due to temperature and shrinkage is the inherent strength variability indicates the necessity of different safety indexes in ultimate failure analysis.

7. Masonry wan s in nuclear plants usuan y have openings and j attachments.

Their effects on wall stability under seismic loading i

are unknown and cannot be rationally evaluated without testing.

j 8. No test data are available for gapped arching block wans under

! cyclic loading. In some cases, restrainers are provided around the gap to prevent gross sliding; this repair' measure does not necessarily change the wall behavior from gapped arch to rigid arch.

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- ,y CONCLCSICH A review and evaluation of the available information on the applicability of arching theory to unreinforced masonry walls in nuclear power plants has been presented.

NIC, FRC staff, and consultants are firmly convinced that their original position expressed to the licensees in the November 3,1983 meeting is still valid. It is evident that test data are needed to quantitatively determine the effects of different wall geometries, material properties, and boundary conditions on unreinforced block masonry walls'

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resistance to earthquake loading. It is recommended that a confirmatory ,

• testing program be performed to investigate the applicability of arching theory to unreinforced block masonry walls in nuclear > power plants.

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mr.rFJENCES

1. Basid, A. A. and Barris, E. G., " Applicability of Arching Theory to Unreinforced Block Masonry Walls Under Earthquake Loading," l'ranklin Research Center, Philadelphia, PA '

August 1982

2. ' Rebuttal to Applicability of Arching Theory to Unreinforced Block 1 Masonry Walls Under Earthquake Loading,' Computsch Engineering Services, Inc., URS/J. A. Blume & Associates and Bechtel Power ,

Corporation, January 1983 l

3. ' Methodology of Mitigation of Seismic Eazards in Existing Unreinforced Masonry Buildings: Wall Testing, out-of-Plane,"

i ARK report, El Segundo, CA i 1981

4. McDowell, E. L. , McKee, M. E. , and Sevin, E. , " Arching Action Theory of Masonry Walls," ASCE Proceedings, Journal of the Structural

! E17.111ED,ST2.

March 1956 t

5. Gabrielsen, B. , Wilton, C. , and Kaplan, K. , " Response of Arching Walls and Debris from Interior Walls caused by Blast Loading," Report i No. 7030-23, URS Research Company, San Mateo, CA i Pobruary 1975 j 6. Drysdale, R. G. and Hamid, A. A., " Capacity of Concrete Block Masonry l Prisons Under Eccentric Compressive Loading," ACI Journal, 1

Proceedings, Vol. 80 March-April 1983 i

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Mr. W. S. Wilgus Crystal River Unit No. 3 Nuclear Florida Power Corporation Generating Plant cc: l Mr. R. W. Neiser Bureau of Intergovernmental Relations i Senior Vice President 660 Apalachee Parkway and General Counsel Tallahassee, Florida 32304 Florida Power Corporation P. O. Box 14042 Mr. Wilbur Langely, Chairman St Petersburg, Florida 33733 Board of County Commissioners Citrus County Nuclear Plant Manager . Inverness, Florida 36250 Florida Power Corporation P. O. Box 219 Crystal River, Florida 32629 Mr. Robert G. Borsum Babcock & Wilcox Nuclear Power Generation Division Suite 220, 7910 Woodmont Avenue Bethesda, Maryland 20814 Resident Inspector U.S. Nuclear Regulatory Commission Route #3, Box 717 Crystal River, Florida 32629 Regional Administrator, Revion II U.S. Nuclear Regulatory Commission 101 Marietta Street, Suite 3100 Atlanta, Georgia 30303 Mr. Ulray Clark, Administrator Radiological Health Services Department of Health and Rehabilitative Services 1323 Winewood Blvd.

Tallahassee, Florida 32301 Administrator Department of Environmental Regulation Power Plant Siting Section State of Florida 2600 Blair Stone Road Tallahassee, Florida 32301 Attorney General Department of Legal Affairs The Capitol Tallahassee, Florida 32304

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