ML20198G098
| ML20198G098 | |
| Person / Time | |
|---|---|
| Site: | Washington Public Power Supply System |
| Issue date: | 11/04/1974 |
| From: | Maccary R US ATOMIC ENERGY COMMISSION (AEC) |
| To: | Moore V US ATOMIC ENERGY COMMISSION (AEC) |
| References | |
| CON-WNP-1009 NUDOCS 8605290234 | |
| Download: ML20198G098 (11) | |
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DistEibution:
l NOV 0 41974 Occket File:
50-460 y
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SEB RF Docket No. 50-460
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l Voss A. Moore, Assistant Director l
for Light Water Reactors Directorate of Licensing WASHINGTON PUBLIC POWER SUPPLY SYSTEM - WPPSS NUCLEAR PROJECT NO.1, SAFETY EVALUATION REPORT OF THE PSAR l
Plant Name: WPPSS Nuclear Project No.1 Licensing Stage: 'PSAR-SER Docket Number: 50-460 Responsible Branch and Project Manager: LWR 2-3, T. Cox Requested Completion Date: November 4, 1971 Applicant's Response Date Necessary for Cor.pletion of Next Action Planned on Project: Unknown Description of Response: Report l
Review Status: Complete The PSAR submitted by the applicant has been reviewed and evaluated by the Structural Engineering Branch, Directorate of Licensing. Our sections of the Safety Evaluation Report are enclosed. This report is based on infomation provided by the applicant through Amendment No. 11 dated October 16, 1974 i
R. R. Maccary, Assistant Director for Engineering j
Directorate of Licensing
Enclosure:
Structural Engineering Branch i '
Safety Evaluation Report cc w/o enc 1:
cc w/ enc 1:
S. Varga. L y
I A. Giambusso, L S. H. Hanauer, DRTA T. Cox, L eg[,f I
W. G. Mcdonald, L F. Schroeder, L L. Shao, L I
K. Goller, L I. Sihweil, L A. Schwencer, L C. P. Tan, L I
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NUCLEAR PROJECT f!0. 1 DOCKET fl0. 50-460 STRUCTURAL ErlGIf1EERIfiG BRAf1CH SAFETY EVALUATI0ft REPORT 3.3 WIl!D AND TORffADO LOADIflGS 3.3.1 Wind Leadings All the plant seismic Category I structures listed in Table 3.2.2 of Section 3.2.1 of the PSAR will be designed to withstand the effects of the design wind.
Seismic Category I systems and com-ponents which are housed within these structures will thereby be protected from its effects.
For seismic Category I systems and components exposed to the wind, they will be designed to withstand its effects.
The design wind specified for the plant has a velocity of 100 mph at an elevation of. 30 feet above grade.
This wind velocity is greater than the maximum velocity of 85 mph determined on the badis of A5CE Paper lio. 3269 for a 100 year period of recurrence.
Chapter 2 of this report presents the basis for establishing this design wind parameter.
The velocity profile, the conversion of wind velocity into equivalent pressure load and the computation of the average wind pressure, on projected areas of a structure are in accordance with ASCE Paper flo. 3269. A gust factor of 1.1 is used in determining all wind loads. ASCE Paper flo. 3269 has been used in previous applications, and has been accepted for use by the Regulatory staff.
3.3.2 Tornado Loadings All Category I structures will be designed to withstand tornado effects.
Therefore all safety-related systems and components located within these structures will be protected from these ef fects.
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The design tornado criteria confona to AEC Regulatory Guide 1.76 for Region III. The tornado has a tangentia~1 velocity of 190 mph, a translational velocity of 50 mph and an associated pressure drop of 1.5 psi at the rate of 0.6 psi per second.
In addition an appropriate spectrum of tornado generated missiles is also postulated.
The tornado velocities will be converted into equivalent pressures on the structures on the basis of ASCE Paper No. 3269 by using a resultant velocity of 240 mph.
The equivalent pressures thus obtained together with the pressure drop and the. tornado i$issile 4
impact will be taken into consideration in the design of Category I structures. As a result the tornado loads will. include wind effects, associated pressure drop and the tornado-generated missile impact load. The tornado loads will be combined with other applicable loads as,will be discussed in Section 3.8 of this report.
The possible failure of non-Category. I structures which are in the vicinity of Category I structures and are not designed to resist tornado loads will be taken into consideration in the design of Category I structures.
3.3.3 Conclusion It is staff's conclusion that the procedures to be used in deter-mining the wind and tornado loadings on Category I structures 4
provide a reasonably conservative basis for engineering design of these structures and are therefore acceptable. The use of these procedures provides reasonable assurance that, in the event of a design wind or a design tornado, the integrity of these structures will not be impaired. Consequently safety-related systems and components located within these structures are adequately protected and will perform their intended safety functions if needed. Con-formance with these procedures is an acceptable basis for satisfying
. in part-the requirement of general design criteria #2.
3.4 WATER LEVEL (FLOOD) DESIGN The plant finished grade ele.vation around the containment and general services building will be EL.466.0 which is well above the flood elevation of 424.5 feet MSL used.in the design of all Category I structures. A detailed discussion on the establish:r,ent of the flood elevation is contained in Section 2.4 of this report.
Since the lower portions of the Category I structures are below the flood elevation, all Category I structures are designed to resist the hydrostatic forces and checked for uplift or overturning considering the buoyant forces. They will be made watertight through the use of water-tight concrete walls and foundation mats covered with waterproofing membrane, and waterstops end' sealants in wall joints.
In addition accesses to all structures will be located above the flood level.
It is concluded that this procedure of design for protection against the effects of water and flood is acceptable.
It provides reasonable assur-ance that in the event of floods, the integrity of Category I struc-tures will not be imoaired.
Ther.efore Category I systems and components located within these structures are adequately protected and will perform their intended safety function if needed. Conformance with this design procedure constituteran acceptable basis for satisfying in part the requirements of general design criterion #2.
- 3. 5 MISSILE PROTECTION 1 s.1 Missilo Barriers Structures, shields and barriers that will be designed to withstand the effects of the various postulated missiles are listed in Table 3.5-1 of the PSAR. The missiles that can potentially impact these structures, shields and barriers are classified into missiles internal to the containment and tornado-generated missiles. They are identified respectively in Tables 3.5-2 and 3.5-3.
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- 3. 5. 2 Missile Selection To be written by APCSA 3.5.3 Selected Missiles To be written by AAB 3.5.4 Barrier Desion Procedure The structures, shields and barriers will be designed to withstand the local effects and overall effects of missile impact.
The most significant local offect of missile impact is perforation of the missile. The concrete barrier thickness required to prevent perforation will be determined by using the Modified Petry formula.
In addition where spalling of concrete might be considered a hazard to personnel or safety-related equipment, the design of the barrier will preclude spalling or additional protection will be provided.
The overall structural response of the barrier due to missile impact will be dctcrained by using established methods of impactive dynamics analysis.
In the analysis various simplifying yet conservative assunptions are to be made.
The missile impact load will be combined with other applicable loads as will be discussed in Section 3.8 of this report.
3.5.5 Conclusions It is concluded that the design procedures to be used to determine the effects of missile impact on structures, shields or barricts are acceptable. These procedures will provide reasonable assurance that the structures, shields or barriers can resist the effects of missile impact without compromising their integrity. Safety-related systems and components located within these structures or behind these shields or barriers are, therefore adequately protected.Conformance with those procedures is an acceptable basis for satisfying in part the requirements of general design criteria #2 and /!4.
. 3.7 SEISMIC DESIGN 3.7.1 Seisraic Input The seismic input design response spectra and damping values to be applied in the design of Seismic Category I structures, systems, and components, comply with the requirements of AEC Regulatory Guide #1.60, " Design Response Spectra for Nuclear Power Plants"
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and Regulatory Guide #1.61, " Damping Values for Seismic Analysis of Nuclear Power Plants."
The synthetic time history to be used for seismic design of Category I plant equipment is adjusted in amplitude and frequency to envelop the design response spectra specified for the site.
Conformance with the quide requirements provides reasonable assurance that, for an earthquake of 0.1259 peak acceleration for 1/2 SSE or 0.25g for the SSE, the resulting accelerations and displacements to be imposed on Category I structures, systems and components are adequately defined to assure a conservative basis for the design of such structures, systems and components to withstand the consequent seismic loadings.
Soil-structure interaction will be considered in the seismic analysis of all Category I structures using the lumped mass and soil spring
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approach.
We conclude that the seismic input criteria proposed by t!'e appli-cant are acceptable for seismic design.
3.7.2 Seismic System Analysis 3.7.3 Seismic Subsysten Analysis Modal response spectrum and time history methods for rulti-degree-of-freedom systems will form the bases for analyses of all Category I structures, systems and components. Governing modal response para-meters will be combined by the square root of the sum of the squares method to obtain the maximum response, when the modal response spec-trum method is used.
Three components of seismic' motion will be considered:
two borizontal and one vertical. The total response of the three components will be obtained by the square root of the sum of the squcres method.
Floor spectra inputs to be used for design and test verification of systems and components will be generated from the time histery raet-hod. Dynamic analysis of vertical seismic systems will be employed for all structures, systems end components where structural cmplifi-cations in the-vertical direction are significant. System and subsystem analyses will be performed on an elastic basis.
Effects on floar response spectra of expected variations'of stru?tural properties and damping will be accounted for by widening the response spectra peaks by at least + 10%.
We conclude that the dynamic methods and prc:edures for seismic sys-tems proposed by the applicant provide on acceptable basis for seismic s
design.
3.7.4 Seismieinstrowntntynprngnm The type.nunter, location and utilization of strong notion accelero-graphs to record seismic events and to provide data on the frecuency, amplitude and phase relationship of the seismic response of Category I structures wl11 correspond to the recom.r.endations of Regulatery Guide 1.12.
Supporting instrumentaf.fon will be installed on Category I structurcs, systems and components in order to provide data for verification of the seismic responses determined analytically for such Category I items.
We conclude that the Seismic Instrumentation Program prcposed by the applicant is acceptable.
3.8 0F. SIGN OF CATEGORY I STRUCTURES 3.8.1 Concrete Containment The nuclear steam supply systein will be completely enclosed by a seismic Category I contair. ment structure. The coritainment structure will be 'n the form of a right cylinder with a hentspherical deme and wjtn t
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approximate internal dimensions of 150 feet in diameter and 235 feet from the top of slab to dome apex. The base slab, the cylinder wall and dome for the containment will be reinforced concrete. The
' cylindrical wall thickness will be a nominal 4'-6" while the dome thickness will vary from 4'-6" at the spring line to 3'-6" at the crown.
A welded steel liner will be attached to the interior of l
the containment to form a leak tight barrier. The functional performance of the containment is discussed in Section 6.2 of this report.
j The containment structure will be designed in accordance with the design criteria as outlined in the Article CC-3000 of the Proposed Standard Code for Concrete Reactor Vessels and Containmer% ACI-l ASME 359,1973 edition, with modifications as requi, red by the staff.
l The containment will be designed to resist various combinations of dead and live loads; test pressure and test temperature, environmental loads including those due to. wind, tornados, and the operating basis and sate shutaown earthquakes; and loads generated by the design basis accident including pressure, temperature and associated pipe rupture effec ts. The static analysis for the whole containment vessel will l
l be accomplished by using the finite elcment method and assuming the containment vessel as axisymmetric with elastic material properties.
l In addition, local areas around large openings such as equipment l
hatch and main personnel lock will be analyzed independently using three-l dimensional finite element idealization. The steel liner analysis will be performed by taking a circumferential strip of unit width of liner cxtending approximately (20) anchors with one panel buckled and sub-jected to forces due to various loading combinations.
This ideal-ized liner system will be analyzed by using a nonlinear finite elcment computer program.
i liaterials of construction, construction methods, quality assurance and quality contrcl measures to be used are adequately covered in the apprcpriate sections of the PSAR.
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. 9 Prior to plant operation,. the containment will be subjected to a structural acceptance test in accordance with Reculatory Guide 1.18.
For the test the internal pressure will be 1.15 times the containment design pressure of 46.4 psig.
The applicant has itemized, in Section 3.8.1.2 of the PSAR, those regu-
.lations, codes, standards, and regulatory guidos that will serve as the basis for the design and construction of the containment.
The use of these criteria in defining:
(1) the applicable codes and specification, (2) the loads and loading combinations, (3) the design and analysis procedures, and (4) the materials, quality control and testing, provides reasonable assurance that the containment structure can with-stand the specified design loads without impairment of its structural integrity and safety function. We conclude that conformance with those criteria constitutas an acceptehle basis for satisfyit:; the requirements of AEC General Cosign Criteria 2, 4,16, and 50.
3.8.2 Steel Containment This section does not apply to this plant.
3.8.3 Concreto and Steel Internal Structures The seismic Category I internal structures consist of a concrete primary shield wall surrounding the reactor, secondary shield walls surrounding the reactor, secondary shield walls surrounding the remainder of the nuclear steam supply system, and refueling canal and operating and intermediate floors, and platforms.
The shield walls will be designed to provide structural support for the nuclear steam supply system as well as shielding. The internal structures will be built of reinforced concrete or structural steel. They will be designed in accordance with the ACI-318 Code,1971 edition for reinforced concrete and AISC specification for stru::tural steel.
The applicant will consider all
. the loads that rray act on the structures during plant lifetime such as daad and live leads, accident induced loads including pressure an'd jet loads, and seismic i
- The load combinations used will cover all cases likely to occur and will include all loads that may act simultaneously.
Design loads for the internal structures are listed and described in paragraph 3.8.3.3 of the PSAR.
The structural design of the internal structures will be evolved through two design stages.
In the first stage of design, the structural components of tne internal structures will be designed individually for various governing loading conditions with simplified assumptions of geometry and the boundary conditions.
In a subsequent state of the design analyses, the interior structure will b;2 analyzed in rare detail through the use of finite clement cethod.
Calculated deflections or deformations of the structures and supports will be checked to assure that the functions of the containment and safety feature systens will not be, impaired.
The use of these design procedures and criteria provides reasonable assurance that the seismic Category I cantainment internal structures will withstand all the specified design loads (including those due to earthquakes and various postulated accid.nts occurring within the containment) without impain.unt of their structural integrity. and safety function. 1le conclude that conformance with these criteria constitutes an acceptable basis for' satisfying the requirements of AEC General Design Criteria 2, 4,16, and 50.
3.8.4 Other Catecary I_ Structures Category I structures other than the containment end its interior structures will be built either from structural steel or from rein-forced ennerete or a combination of the two.
The structural corponents will consist of slabs, walls, beams and columns.
The design criteria for reinforced concrete will follow those specified la the AIC-318
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Code. Structural steel components will be designed in accordance with the AISC specifications.
The various conditions used in the design of these Category I structures will include an appropriate combination of loads likely to occur during normal operation or shutdoun, and during postulated accidents and earthquakes.
The use of these design criteria will provide reasonable assurance that the Category I structures outside containment will withstand all the specified loads without impairment of their structural inte-grity cnd safety functions. We conclude that conformance with these requirements constitutes an acceptable basis for satisfying the require-ments of AEC General Design Criteria 2 and 4.
3.8.5 Foundations and Concrete Supports The foundation of the containment will be a reinforced concrete cir-cular mat, 200 feet in diameter and 18 to 20 feet in thickness.
It will ho analy7ed to deternine the effects of various combinations of loads expected during the life span of the plant. The analysis will be accomplished by means of a computer program taking into account the bending moments, shears, and soil pressures for a synmetrically loaded circular plate on an elastic foundation.
Foundations of other ma.ior structures, such as the fuel building, the auxiliary building and the main control area in the service building also will consist of rectangular reinforced concrete mats.
The foundations will be designed in accordance with the ACI-318 Code.
We conclude that use of the above design and analytical methods for foundations constitutes an acceptable basis 1or satisfying the require-ments of AEC General Design Criteria 2 and 4.
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