ML19220B424
| ML19220B424 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 02/04/1976 |
| From: | Maccary R Office of Nuclear Reactor Regulation |
| To: | Deyoung R Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 7904260016 | |
| Download: ML19220B424 (22) | |
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Di s tribution:
Docket File: 50-320 NRR-Rdg SE3-Rdg Cccket No.
50-320
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MS 24-13
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R. C. DeYoung Assistant Director for Light Watar Reactors Division of Project Management METRCPOLITAN EDISON CD. - THREE MILE ISLA'iD NUCLEAR STATION UNIT v2 FSAR-OL REVIEW SAFETY EVAL"ATION RE. CRT (STRUCTURAL)
Plant Nam: Three Mile Island, Unit 12 Licensing Stage:
FSAR - OL Review Docket Nt.mber: 50-320 Responsible Branch and Project Manager: LWR 2-2; Harley Silver Requested Completion Date: January 30, 1976 Applicant's Response Date Necessary for Completion of Next Action Planned on Project: As Scheduled Description of Response: Report Review Status: Corr.plete The FSAR submitted by the applicant has been reviewed and evalva*2d by the StnJctural Engineering Brtnch, Division of Systems Safe'.y.
Our sections of the safety evaluation are enclosed. This evaivation is based on infon ation provided by the applicant through Amcndmnt No. 37 dated January 20, 1976.
R. R. Maccary, Assistant Director for Engineering Division of Systems Safety
Enclosure:
Structural Evaluation for Three Mile Island, Unit f2 e
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R. Boyd, PM R. Heineman, SS H. Silver, PM W. McDcnald, MIPC S. Va rga, N A. Gluckmann, SS K. Kniel W X. Kapur, SS I. Sihweil, SS C. Tan, SS DSS:SEB DSS:SEB DSS:SEB DSS:SES gD:
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THREE MILE ISLAND, UNIT #2 STRUCTURAL ENGINEERING BRANCH FSAR SAFETY EVALUATION REPORT 3.3 Wind and Tornado Loadines All the Category I structures exposed to wind were designed for a wind velocity of 80 mph. Studies by the Weather Bureau indicate that th'is velocity is slightly larger than the velocity of 70 mph which may be exceeded once in 100 years. Wind pressures, shape factors, gust factors, and variations of wind velocities with height mere determined in accordance with the American Society of Civil Engineers, Paper No. 3269, " Wind Forces on Structures."
All Category I structures were designed to resist a tornado of 300 mph tangential wind velocity and a 60 mph translational wind velocity.
The simultaneous atmospheric pressure drcp was assumed to be 3 psi in 3 seconds in the design of the Reactor Building which must remain sealed through the tornado event. All other Categc;y I structures are proviced either with adequate areas of openings to relieve the differential pressure of 3 psi in 3 seconds or are designed to with-stand a differential pressure of 3 psi.
The tornado forces have been applied uniformly irrespective of the height of the structure above grade considering a gust factor of 1.0.
The pressure distribution and forces are computed in the manner similar to that described in ASCE Paper #3269.
Furthermore appropriate tor-rmdo missiles have also been postulated in the design.
Tne use of these loading criteria provides reasonable assurance that, in the event of wind or tornados, the structural integrity and safety function of Seismic Category I structurer will not be impaired by the specified environmental forces. Conformance with these criteria is an acceptacle basis for satisfying the requirements of General Design Criterion #2.
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O 3.4 Wate,.evel (Flood) Desicn The design flood level resulting from that condition or combination of conditions, such as the maximum probable flood with coincident wind wave action and other natural phenomena, that produce the maximum water level of the site is discussed in Section 2.4, Hydrol-ogy.
Unit #2 design is based on a water elevation of 300'-0" under flood condition. Structures containing Engineered Safety Features are sealed against entry of flood water to an elevation of 312'-0".
Complete protection has been provided at the exterior faces of these structures. The waterstops between adjacent building walls and mats are capable of withstanding a maximum water head of 45 feet which is in excess 'f maximum head for the flood level. The exterior sliding doors and flood panels are provided with watertight seals. The vital equipment in the R'ver Water Pump House is located above elevation 312 ' -0". Additior,al flood protection measures are discussed in 2.4.10.
The maximum water level considered is 2'-0" higher than the PMF elevation expected around the station facilities.
The foundation mats, exposed walls and flood panels of Category I structures are designed to withstand the hydrostatic pressures corres-pending to a water level of 311'-0".
Static forces on the flood panels and vertical walls are calculated considering hydrostatic pressures. The buoyancy forces on the mats are calculated considering the uplift due to the height of water above the botto,n of the mats.
The use of these design loading criteria provides reasonable assurance that, in the event of flooding, the Seismic Category I structures can be expected to withstand the specified environmental forces without impairment of their structural integrity and safety function. Co nfo r-mance with these criteria is an accr.ptable basis for satisfying the
9 requi ren er '.: :f General C ria #2 and #4 as related to environ-mental desi.
basie for a 1c' t es.
38 Miss P _1-tection Criteria i t.: plant 1.17
. structures and components were shielded from, or designed f:-
tne various postulated missiles including airplane impact. Mir.iles considered in the design of these structures and components
- iude tornado generr.ced missiles and various containment internal mi _ les, such as those associated with a loss-of-coolant accident at
.;rbine failure. The design of structures for missile impact was
- crmed using the most conservative results of computa-tions basc:
- the following formulas and considerations:
a.
Modific etry Formula b.
Army Cs of Engineers c.
Ballist Research Laboratory d.
The dcs.
for airplane impact is presented in Appendix 3A.
The missilt 33umed to have been generated by the tornado event are listed in,
'e 3.3-1.
They include items such as siding panel, pipe, steel plat.
tc., which could be detached from non-Category I structures under torr.
associated loadings. Their effects on the Category I buildings considered together with the effects of loadings described
.3.2.1.
Thus, the ability of Category I buildings to perform wi at be jeopardized 7.s a result of flying objects from the non-C:-
ry I structures under a tornado event.
The use o'
- e criteria for protection frca postulated missiles provides <
- able assurance that resulting loads and effects will not impai-structural integrity of Category I structures, or result in loss of function of Safety related systems and comoon-ents conc:
in such structures. We have concluded that conformance with thest
- eria is an acceptable basis for saticfying General Design Cr'
' #2 and #4.
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3.7 Seismic Desien 3.7.1 Seismic Inout The seismic design response spectra curves and damping values were presented in the PSAR and approved prior to the issuance of the construction permit for the Three Mile Island, Unit 2.
The modified earthquake time histories used for component equip-ment design are adjusted in amplitude ~and frequency to envelope the response spectra specified for the site. We conclude that the seismic input criteria proposed by the applicant provides an acceptable basis for seisric design.
3.7.2 Seismic System Analysis 3.7.3 Seismic Subsystem Analysis Modal response spectrum multi-degree-of-freedom and normal mode-time history methods are used for the analysis of all Category I structures, systems and components. The vibratory motions and the associated mathematical models account for the soil structure interaction and the coupling of all coupled Category I structures and plant equipment. Governing response parameters have been com-bined by the square root of the sum of the squares to obtain the modal maximums when the modal response spectrum method is used.
The absolute sum of resconses is used for closely spaced frequencies.
Horizontal and vertical floor spectra inputs used for design and test verification of structures, systems and components were generated by the normal mode-time history method. Torsional loads have been adequately accounted for in the seismic analysis of the Category I structures. Vertical ground accelerations were assumed to be 2/3 of the horizontal ground acceleration and the horizontal and vertical effects were combined simultaneously.
Constant vertical load factors were employed only where saalysis showed sufficient vertical rigidity to preclude significant vertical amplifications in the seismic system being analyzed.
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O O We have reviewed the FSAR and applicable amendments and find the seismic system and subsystem dynamic analysis methods and pro-cedures proposed by the applicant to be acceptable.
3.7.4 Seismic Instrumentation Program The type, number, location and utilization of strong motion accelerographs to record seismic events and to provide data on the frequent.y, amplitude and phase relationship of the seismic response of the containment structure corresponds to the reco-
=mendations of Reculatory Guide 1.12.
Supporting instrumentation will be installed on Category I structures, sys6 ems, and components in order to provice data for the verification of the seismic respor.ses determined analytic-ally for such Category I items.
We conclude that the Seismic Instrumentation Program proposed by the applicant is acceptable.
3.8.1 Concrete Containment The containment is a reinforced concrete. structure composed of a cylindrical wall with a flat foundatian mat and an ellipsoidal dome.
The foundation slab is reinforced with conventional reinforcement.
The cylindrical wall is prestressed in the vertical and hoop direc-tions. The dome is prestressed utilizing a three-way post-tensioning system. The inside surface of the containment is lined with a carbon steel liner. The lir.er plate thickness is 3/8 in. for the cylinder, 1/2 in. for the dome and 1/4 in, for the mat.
The foundation mat is bearing on rock and is 11 ft. 6 in. thick with a 2 ft. thick concrete slab above the base liner plate. The cylinder has an inside diameter of 130 ft., a wall thickness of a ft. and a height of 157 ft. from the top of the foundation slab to the spring line. The roof is a shallcw dome having a large radius of 110 ft.,
a transition radius of 20 ft. 6 in and a thickness of 3 ft. 6 in.
- /G-040
Q e The S/H 54-5 tendon-anchorage system, as developed by Stressteel Corporation (see Appendix 3C), has been used to prestress the shell.
The ultimate capacity of the system is 2230 kips. The configuration of the tendons in the dome is based on a three-way tendon system consisting of three groups of tendons critated at 60 with respect to each other. These tendons are curved in the horizontal plane (as necessary) near the ring girder to make their alignment radial at the anchorages. The cylindrical portion of the wall is pre-stressed with a system of vertit.11 and hcop tendons. The hoop-tendon system consists of a series of remi-circular rings teruinating alternately at pairs of the four buttresses which are used to anchor the rings.
The prostressing system is similar to the prestressing system used in Unit #1. The applicant has provided all the information needed to justify the modifications incorporated into the Unit 42 system as compared with the Unit #1 system.
The tendons are grouted to protect them against corrosion.
The static analysis 'or the containment was based on the thin shell theory with elastic material behavior. Results frca the base slao analysis were used as boundary conditions for the analysis of the shell.
The choice of the materials, the arrangement of the structures, the design criteria and design methods are similar to those evaluated for previously licensed plants.
The stresses computed by the applicant are below the code allowables.
Materials, construction methods, quality assurance and quality con-trol measures were adequately covered in the FSAR and, in general, are similar to those used for previously accepted facilities.
The applicant is ccamitted to perform periodic structural proof test during the 2nd,10th and 20th years after the start of the commercial operation of the plant as a means to cemonstrate the continued integrity of the containment.
Mi-C A. i
_ The Regulatory Guide which has been applied in the construction or testing of the structural parts of the plant is R. G. #1.15:
Testing of Reinforced Sars for Concrete Structures.
The foundation of the containment system is a circular mat a.id was analyzed to determine the effects of various combinations of loads expected during the life span of the plant. Analysis has been accomplished by means of a digital computer taking into account the bending moments, sheai s, and soil pressures for circular plate.
The use of these design criteria defining the applicable codes, the loads and loading combinations; the design and analysis procedures, the materials, quality contrei and the testing provide reasonable assurance that, in the event of winds, tornados, earthquakes and various postulated accidents occurring within the containment, the Seismic Category I containment structure will withstand the specified conditions without impairment of its structural integrity and safety function. Conformance with these criteria constitutes an acceptable basis for satisfying the requirements of General Design Criteria #2,
- 4, !16 and #50.
3.8.3 Concrete and Structural Steel Internal Structures cf Concrete Containment The containment interior structures consist of a shield wall around the reuctor, secondary shield wall and other interior walls, compart-ments and floors.
The interior structures were designed in accordance with the ACI-318 Code for concrete, and the f.ISC specifications for structural steel, and the PSAR.
The applicant has considered all the loads which may act on the structure during its lifetime, such as dead and live loads, accident induced loads including pressure and jet loads, and seismic loads.
'it, 042
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. The load combinations used cover all cases likely to occur and include all loads which may act simultaneously.
In the design of concrete interior structures, the working stress and the ultimate strength methods were used for all load conditions.
The use of these design procedures and criteria provides reasonable assurance that the Category I containment internal structure will withstand all the specified design loads (including those due to earthquakes and various postulated accidents occurring within the containment) without impairment of the structural integrity and safety function. Conformance with these criteria constitutes an acceptable basis for satisfying the requirements of General Design Criteria 12, #4, fl6 and #50.
3.8.4 Other Catecary I Structurle Category _I structures other than containrent and its interior were built frca structural steel and reinforced concrete members. The structural components consist of slabs, walls, beams and columns. The design method for reinforced concrete followed that specified in the ACI-318 Code. Structural steel comoonents were designed in accordance with the AISC specification.
The various conditions used in the design of Category I structures include an appropriate combination of loads likely to occur during normal operation or shutdown, during postulated accidents and earthquakes. These combinations are similar to those accepted in the past.
We have concluded that conformance with these criteria, codes and specif' cations in designing Category I structures other than the contair:nent structure constitutes an acceptable basis for satis-fying the requirements of criteria 2 2nd 4 of the General Design Criteria.
3.8.5 Foundations and Concrete Succorts The foundations of major structures, such as fuel building, auxiliary building consist of reinforced concrete mats.
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The foundations were designed in accordance with the ACI-318 Code.
The use of the above design and analytical cethods constitutes an acceptable basis for satisfying the requirements of General Design Criteria #2 and #4.
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Bibliocrachv Section 3.3 Wind and Tornado Loadings 3.3-1
" Wind Forces on Structures," Final Report of the Task Cc==1ttee on Wind Forces of the Cc= ittee on Load and Stresses of the Structural Division, Transactions of the American Socie.. of Civil En;ineers, 345 East 47th Street, New York, N. Y. 1C017, Paper No 3269, Vol. 126, Part II, 1961, p. 1134-1198.
Section 3.5 Missile Protection 3.5-1 A Amirikian, " Design of Protective Structures," Bureau of Yards and Docks, Pcblication No. NAVECCKS P-51, De-part=ent of the Navy, Washington, D.
C., August I?30.
3.5-2 R. C. Cwaltney " Missile Generation and Protection in Light Water Reactors," CRNL-NSIC-22 Oak Ridge National Laboratory, March ', 1967.
Section 3.7 Seismic Design 3.7-1 USAEC Regulator i Guide 1.60 " Design Response Spectra for Nuclear Powe; ?lants."
3.7-2 USAEC Regulatory Guide 1.o. " Damping Values for S.ciscic Analysis of Nuclaar Pouer Plants."
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3.7-3 USAEC Regulatory Guide 1.12 " Instrumentation for Earthquakes.'I 3.7-4 Kapur, Kanuar K., "Seis=ic Instrumentation for Nucicar Power Plants," Topical Meeting on Water-Reactor Safety, Salt Lake City, Utah, March 1973, A=crican "uclear Society.
Section 3.8 Design of Category I Structures 3.8-1 A=crican Ins titute of Steel Constructica, "Specifica:ica for Design, Fabrication & Erection of Strue: ural Secci for Buildings, 101 Park Avenue, New York, N.Y. 10017, 1963 3.8-2 A=crican Concrete Institue, "Suilding Code Require = cats for Reinforced Concrete (ACI 313-1963)," P.O. Sox 4 754, Redford Station, Detroit, Michigan 48219.
3.8-3 Accrican Society cf Mechanical Engineers, "AS:3 Boiler
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and Pressure Vessel Code,"Section II, Section III, and Addenda, and Sections VIII & IX, United Engineering Center, 345 East 47th Street, New fori, N.Y. ICC17.
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