ML19317G715
| ML19317G715 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 04/10/1968 |
| From: | Morris P US ATOMIC ENERGY COMMISSION (AEC) |
| To: | Davis E SACRAMENTO MUNICIPAL UTILITY DISTRICT |
| References | |
| NUDOCS 8003270691 | |
| Download: ML19317G715 (20) | |
Text
{{#Wiki_filter:. SUPPLU S!TAL UNITED STATES i bvi l' t. ATOMIC ENERGY COMMISSION
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- l WASHINGTON. O.C.
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- o,,,,, s' Docket No. 50-312 pg 10 9 Sacramento Municipal Utilities District Post Office Box 15830 Sacramento, California Attention:
Mr. E. K. Davis General Counsel Gentlemen: Our letter of March 21, 1968 requested information on your application for a construction permit for the Rancho Seco Nuclear Generating Station. That request for information did not relate to Sections 2.5 and 5.0 of your PSAR. i In our review of the information submitted on proposed structures for the l facility, we have found many areas where the information was insufficient for our needs. During the course of meetings with your representatives, we have advised them in some detail of the nature of our concerns. In general, it will be necessary for you to provide information relating to the basic definitions for the different categories of structures, provide lists of structures in each category, provide information on the proposed design of all essential foundations and structures, including information on loads, load combinations, allowable atress and deformation limits, methods of static and dynamic analysis, selection of materials, corrosion protective measures, quality assurance And control requirements, and testing and surveillance specifications. The need for information in these areas was discussed with your representa-tives during their visit to our Bethesda office on March 1, 1968. Examples of the kind of information needed are given in Enclosure No. 1. We would be glad to discuss further any uncertainties you may have as to the type and extent of the material required. [ 8003270 V
Sacramento Municipal Utilities District. Since meeting with you on March 1,1968, ue have continued discussions with our consultants on your application. Questions which have been identified since our last meeting are included in Enclosure No. 2. Sincerely yours, cr'ef'n! rr,w y I'st:r 4. *Joms Peter A. Morris, Director Division of Reactor Licensing
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Request for Information - Supplement No. 1 Sacramento Municipal Utilities District (Docket No. 50-312) April 5, 1968 5. CONTAINMENT SYSTEM 5.1 Methods and criteria 5.1.1 Provide complete lists of all: (a) Class I Structures,, (b) Class I Components, 1 (c) Class II Structures, ) (d) Class II Components, (e) Combined structures, i.e., structures consisting simulta-neously of Class I and Class II elements, and (f) Class I equipment housed in or adjacent to, or supported by, Class II structures. 5.1.2 Describe the protection which will be provided to Class I equipment which are not located in, or supported by, Class I structures. 5.1.3 State how the earthquake loads for these Class I components will be established, since they are not supported by Class I structures. 5.1.4 Describe the design methods used for combined (Class I and Class II) structures. 5.1.5 For plant structures and equipment rated other than Class I, indicate in detail the design criteria for seismic loading. 5.1.6 It appears from the PSAR that the foundations of the containment and other structures will rest on layers of sands, gravels, silts, and silty clays. It is not stated whether these materials are insensitive to accelerated weathering, or whether they expand when exposed to the atmosphere, during construction. Provide information on: (a) The extent to which the above are true; (b) The construction procedure that will be used to avoid damage to these materials during the time interval between excavating and installing of foundations; how they will be protected; l%
+ ~ a , (c) What the shape of the excavation will be; how the excavation will be drained; (d) The provisions that will be made to accommodate differential settlements during earthquakes. 5.1.7 Justify the 1 cad factors used for Class I structures other than the containment. Indicate design methods. Provide a list of codes, standards & specifications on which the design & construc-tion will be based.- Where applicable consider transient thermal gradients instead of steady state gradients. 5.2 Containment Structural Desian 5.2.1 In certain circumstances the containment structure base may be located below water level. It. appears that no layer of porous concrete and no membrane water-proofing exists between the soil and the containment. Consider the possibility of cracking of the concrete in the base mat, in the cylindrical vall and in the prestressing gallery. Ground water may reach the liner and the prestressing tendon anchors. The effect on the stability of the liner and possible corrosion of liner and tendons should be investigated. Explain drainage provisions at the containment lower section. 5.2.2 Provide the following: (a) A preliminary design drawing of the containment, presenting details of the base slab, done ring beam, cylinder-slab juncture, vertical buttresses and inspection gallery; showing reinforcing, prestressing, and liner features, including liner anchors; (b) Scaled load plots for moment, shear, deflection, longitudinal force, and hoop tension, in order that an appraisal can be made of the significance of the various loadings which influence the containment design; Provide these plots as a function of containment height for prestress, dead, pressure, design earthquake, wind, liner thermal (normal and accident) and concrete thermal (normal and accident) loading; (c) The normal operating transient and steady state thermal gradients to be used in the design of the containment for typical winter and typical summer day; (d) The transient and staady state thermal gradients through the containment envelope during the design basis accident i for typical winter and typical summer day. l i L l
i . 5.2.3 The thermal load from the liner is a function of the stiffness of the encasing concrete and its deformations. It is therefore necessary to define and to justify the values of the Young's modulus and of the Poisson's ratio,ist the values of E , L( e for cracked and uncracked rein-Ie forced concrete structure. L anq,(/c for e i l different elevations and explain their use in the design of the concrete shell and in thermal liner loading computations. Include the effect of shrinkage and creep. ~ 5.2.4 The thermal load from the liner is also a function of the thick-ness of the liner plates, and of the yield point of the liner steel. Thh thickness of the two adjacent liner plates may vary by as such as 10%. In addition, only the minimum yield point is indicated in PSAR, but not the maximum yield point, which may differ from the minimum by as much as 25% - 30%. Explain how the variations of thickness and yield point are considered in the design. 5.2.5 Por the loadings of the containment structure wall and dome, describe: (a) The analytical procedures used for arriving at the forces, shears, and moments in the structural shell, considering that the structure is not axisynetric (buttresses); (b) The considerations given to, and the analytical procedures for determining discontinuity stresses at the base, at the done (ring girder), and at the buttresses; the assumptions with regard to structural stiffness that form the basis for these stress determinations; the variations of E and e e considered. 5.2.6 It is not clear whether the computer program which is used for the design will take into account the cracking of concrete, and the resulting variation of E anq,6( e. Should not the program e also be able to handle loadings that are not axisynetric which act on structures that are not axisynetric2 5.2.7 If the effect of temperature rise in the liner will be repre-seated by a uniform pressure increase, provide a justification for this approach. 5.2.8 Indicate whether the following has been considered: (a) Possible reversal of stresses, due to creep during cold shut down;
r " F (b) Cracking of the cylindrical wall, which makes it more flexible j than the uncracked mat; (c) Capacity of the ground around to restrain deformations of the wall. 5.2.9 For the loadings of the base slab, describe the analytical proced-ures used to arrive at the forces, moments, and shears, considering loading that is not axisymetric and deformations of the mat. State whether you considered transient thermal gradients. 5.2.10 What were the elastic properties of the soil ussd for design of the mat? 5.2.11 Provide some clarification of the design procedures and stress limits by describing the extent to which liner participation is relied upon to provide resistance to lateral (earthquake) shear; If liner participation is not included, describe hc.w the corre-sponding strains are transmitted to the liner and their effect on the liner. Consider possible cracking of concrete. 5.2.12 Explain whether one-third increase in allowable stresses will be used. This increase in allowable stresses is not considered in keeping with its usage in normal practice, particularly with respect to the D + L + S t T loadf.ng. Discuss this problem and provide a criterion that consides biaxial and triaxial loading effects. Justify the values of shear (as a measure of beam strength in diagonal tension) for a structure of this type. Discuss your design criteria in this area, keeping in mind possible biaxial tension stresses, and two-dimensional cracking. 5.2.13 Under incident conditions concrete may be cracked and the crack pattern may be two-dimensional. Explain how, under this condition, i the radial, vertical, and tangential shears are transferred through the section. 5.2.14 The reinforcing steel may be stressed to the yield point. "This stress is larger than the guaranteed minimum yield point of the ) liner which is 30,000 psi. Does this mean, that, under certain conditions, the liner say be stressed beyond the yield point in shear? Clarify this point. 5.2.15 Because of cracking of concrete due to shrinkage, to testing, to thermal stresses and during an accident, the problem,of adequate bar anchorage is of special concern. Provide information on how i the reinforcing bars are anchored at certain critical points, such as: center of done, at intermediate terminal points of radial bars in the done, bars provided to take discontinuity stresses, some diagonal bars,. bars connecting the buttresses to main shell, bars under prestressing anchors, etc? i l i
e f~ 5.2.16 With respect to seismic design of the containment, please describe: (a) The general analytical model for the containment including mass determination and distribution, stiffness coefficients, modes of vibration, and analytical procedures for arriving at a loading distribution on the containment structure. (b) The order of magnitude of lateral earth pressure under seismic loading and indicate how such loading will be factored into the containment design. (c) The manner in which damping will be considered in the structural design. In this description, justify the damping values employed for the various components of the structure, considering possible cracking and different modes. (d) The exteot and manner in which the horizontal, vertical, and rocking motions will be considered in the design, and how the corresponding damping values will be included. Describe the motion of the structure with respect to ground using the above three components of motion. 5.2.17 The design spectra shown in the PSAR, have been scaled from the El Centro spectrum. Indicata the degree to which this scaling was examined in connection with the Rancho Seco site. 5.2.18 With respect to liner design, describe: (a) Types and combinations of loading :onsidered with regard to liner buckling, and the safety factors provided. Include the influence of large tangential strains due to possible opening and closing of cracks in concrete; (b) The geometrical pattern, type, and spacing of liner accach-ments; and the analysis procedures, boundary conditions, and results with respect to buckling under the loads cited above; (c) Tolerance on liner plate thickness and liner yield strength variation and their bases; (d) The possibility of both types of buckling; elastic and inelastic. In this study, discuss the influence of all pertinent parameters, such as: Variation of plate thickness; Variation of yield point of liner steel; Influence of variation of Poisson's ratio; Erection inaccuracies (local bulges, offsets at seems, wrong anchor location); Prestressing; Shrinkage of concrete; Creep of concrete; Variation of Young's modulus and Poisson's ratio for cracked and uncracked concrete, and as a function of stress level in concrete (elastic and plastic); l, Ground water infiltration, and back pressure, earthquake, temperature loading, vacuur loading; and l Furnish sample calculations. l l l .m-.
c . 5.2.19 Provide information on: (a) The stress and strain limits used for the liner, the bases for these 10mits, and the extent to which these limits relate to liner leakage; (b) The type, character, and magnitude of cyclic loads for which the containment liner will be designed, including a discussion of earthquake cycling; (c) The analytical procedures and techniques to be used in liner anchorage design, including sample calculations; and (d) The failure mode and failure propagation characteristics of anchorages. Discuss the extent to which these character-istics influenca leak tightness integrity. What design provisions will be incorporated to prevent anchorage failures from jeopardizing leaktight integrity? 5.2.20 Por the design of the anchors, elastic and inelastic buckling of the liner should be considered as well as the different modes of buckling of adjacent plates. Consider, for the design of the anchors, the possibility of unbalanced loads acting on several anchors. The study should prove that no chain reaction can occur and that the possibility of massive buckling of the liner, and mass failure of anchors is excluded. 5.2.21 What plasti; strains can the liner material accommodate without cracking? 5.2.22 Describe the design approach that will bn av>.J where loadings must be transferred through the liner such as at crane brackets or machinery equipment rounts; provide typical design details and computations. 5.2.23 It is noted that the bottom liner is not accessible for inspection during the life of the plant. It is therefore vary important to avoid any unrecessary stresses and strains in the bottom liner. The arrangement for load transfer through the liner under the bottom of the interior structure should provide for transfer of shears carallel to the liner. Indicate how the shears, especially those due to thermal expansion and earthquake, will be accammodated. 5.2.24 Provide the latsat liner arrangement to be used at the base-cylinder to liner juncture, the strain limits imposed at'the juncture, and an analysis of the capability of the chosen liner crrangement to absorb these strains under the design basis accident and earthquake conditions. Discuss the influence of local cracking on liner anchors. 1 -m
~ . 5.2.25 Describe the analytical procedures for analysis of liner stresses around openings. Also, provide the method of liner design to accommodate these stresses and the related stress limits. Justify the proposed thickening of the liner at penetrations. Discuss the liner anchors at this location. 5.2.26 A general statement that all penetrations will be anchored into the concrete wall and that the anchorage will develop at least tne plastic strength of the penetration sleeve would not be satisfactory if not followed by an explanation what plastic strength is meant. Provide this explanation in terms of the tension, bending, shear, and combined components. 5.2.27 With regard to penetration design, describe: (a) The design criteria to be applied to ensure that piping loads under the postulated design basis accident which could result in pipe rupture or relative displacement of the internal systems relative to the containment, a subsequent pipe rupture due to torsional, axial, bending, or shear, will not cause a breach of the containment. Also, include the detailed design criteria with respect to pipe rupture between the penetration and containment isolation valves. These piping sections represent an extension of the containment boundary under a condition when isolation is required. What codes will be used? Provide typical designs to illustrate how the criteria are applied. (b) The extent to which the penetrations and their surrounding liner regions will be subjected to vibratory loading from machinery attached to the piping systems. Indicate how these loads will be treated in design. (c) The criteria for concrete thermal protection at penetrations; include the temperature rise permitted in the concrete under operating conditions and the (time dependent) effect that loss of thermal protection would have on the containment's i structural and leak-tightness characteristics. What j therpal gradients are used? (d) The manner in which axial stresses, hoop stresses, shear stresses, bending stresses (in two directions) and shear stresses due to torsion are combined in the plastic domain, if the full plastic strength of a pipe with regard to i torsion, bending.and shear is to be used. What failure criterion is used? Indicate how the exterior loads are =. __..
n combined, including jet forces. Give factored loading combi-nations for all loads and all cases considered in the design. Explain how the Standard Code for Pressure Piping-Power Piping, B31.1.0-1967 will be used for all loading cases. Will factored load combinations be used with this code? 5.2.28 Provide criteria with regard to opening sizes that constitute lar5e Openings; hence, meriting special design consideration. List the number and indicate the size of the large openings for the containment. 5.2.29 Add the following information: (a) For all penetrations, indicate the criteria for the bending of reinforcing bars which have to clear the openings. Maximum slope and minimum bending radius to avoid local crushing of concrete should be shown. (b) For penetrations greater than about 9 inches and up to and including about 4 feet, explain how normal, shear, bending, and torsional stresses are covered by the prestressing and by the reinforcing bars. (c) Justify the length required to anchor the bars in cracked concrete, and the use of ACI code 318 or any other code to determine anchorage requirements for concrete under biaxial tension, and cracked in two directions. 5.2.30 With respect to large opening design, describe: (a) The primary, secondary, and thermal loads that will be considered in the design of the openings, and how they were 4 established; (b) The stress analysis procedures that will be used in design; (c) The method that will be followed for the design; the working stress design method or the ultimate strength design method, or both; If the ultimate strength design method is used, the factored load combinations should be given together with corresponding capacity reduction factors; (d) How the existence of biaxial tension in concrete (cracking) will be taken care of in the design; How the normal and shear stresses due to prestressing, to axial load, two-directional shear, and torsion, will be combined; Clarify these points and establish criteria for the design of the thickened part of the wall around the opening (ring girder).
= R. Reference to recent pressure tests of similar openings would l. not be conclusive, since the thermal sad earthquake loads were not applied during tests, and since these tests have not established the safety factor provided in the structure (tests have not been continued till failure occurred). (e) The method to check the design of the thickened stiff part of the shell, around large openings and its effect on the shell; Include prestressing, creep and shrinkage. The comparison with stresses in a circular flat plate would not be convincing, since it eliminates one of the most important effects, i.e. the effect of torsion. Present a method which checks torsional stresses. (f) Additional information on reinforcing pattern,. i.e., reber size and spacing, and prestressing pattera that will be used around large openings; (g) The safety factor provided in design at Isrge openings; Sample computations should be provided, listing all the criteria and analyzing the effect of all pertinent factors such as prestressing, cracking, etc. 5.2.31 List the spectrum of external missiles that the containment will be designed to withstand and the procedures to be used in checking the containment design to withstand such missile hazards. 5.2.32 If insulation is required, present a detailed study of it. Design requirements and performance specifications should be included to provide confidence that the insulating qualities will be achieved ~ under accident conditions. Hence, provide a description of: (a) The specified and tolerable temperature rise in the liner and the design safety factor provided on insulating performance; (b) Means provided for fastening the insulating material to the backing liner and for precluding steam channeling in back of the insulation (from the top or through joints) and state whether the insulating panels be removable; (c) An analysis of the consequences of one or more insulation panels being displaced from the liner during, or as a consequence of, an accident situation; (d) The consideration given to increased conductivity due to humidity and compression during accident pressure transients and precompression from structural and leakage testing; L
_ (e) The consideration that will be given to the compatibility of the insulation and liner. 5.2.33 Provida a description of the procedures used for analyzing anchorage zones and provide typical results of such analyses. Include consideration of biaxial tension in concrete. 5.2.34 Provide typical details of anchorage zone reinforcing. Provide information that support its adequacy to resist the imposed anchorage loading (particularly under long-term loading). Justify bond values used for anchorage of reinforcing bars. 5.2.35 Indicate the criteria by which reinforcing steel will be provided in the containment shell for crack control, considering possible reversal of stresses during cold shut-down. 5.3 MATg11ALS 5.3.1 Justify the type cement to be used, explain the bas,is for its selection, and describe the user verification testing to be performed. 5.3.2 Indicate the specifications to be used for the concrete aggregate and indicate the testing to be performed to assure the suitability of the selected aggregate. Indicate the specifications to be applied to the mixing water and the limits to be prescribed on i agents which may attack prestressing tendons. 5.3.3 Describe the concrete mix procedures and indicate the scope and extent of testing of trial mixes. Indicate the type and extent of admixtures which may be used. Describe their purposes, their extent of compliance to ASTM specifications, and their testing. Describe the choice of slump values and list them. 5.3.4 Indicate, in detail, the extent to which splice stagger will be achieved. i 5.3.5 Indicate the extent to which splicing Of reinforcing steel will be made by welding. State the location of these welds. 5.3.6 Add the description of the " splicing" of inclined bars, or horizontal stirrups provided to take the radial shears in the walls, with the vertical bars. If the " splicing" is done by lapping the diagonal bar with a vertical bar, or by bending the stirrup around a vertical bar, demonstrate that, despite biaxial tensile stresses in concrete and vertical and horizontal crack pattern, the load in the diagonal bars or stirrups can l safely be transmitted to the vertical bars. l l l l
) - l 5.3.7 Specify quality control for the strength welds of reinforcing bars to structural elements such as plates, rings, sleeves, and for occasional strength weld splicing of heavy reinforcing bars. 5.3.8 Provida the detailed material selections for containment penetra-tions, listing the corresponding ASTM specifications and indicating the NDTT considerations in their selection. 5.3.9 Provide a detailed description of the prestressing materials and hardware selected. Justify the prestressing system selection. This should include data with regard to ultimate tendon strength, elongation, anchorage strength, hardware dynamic petformance, conduits, etc. 5.4 CORa0SION PROTECTION _ 5.4.1 Describe the concrete cover provisions for reinforcing steel for the dome, slab, and cylinder. Include, for comparison, the minimum ACI 318-63 code requirements. 5.4.2 Discuss the extent to which cathodic protection has been considered and is being provided. State whether soil resistivity surveys have been conducted'and, if so, provide the results. 5.4.3 Discuss the extent to which protective coatings will be applied to the liner. 5.4.4 Discuss the corrosion protection of the prestressing system. 5.4.5 Drainage provisions do not include a layer of porous concrete located at base. Also no provision has been made for a porous layer at the cylindrical wall of the containment. Justify the omission of drainage at such a critical location. Consider that, ccatrary to normal foundation work, the containment structure is continuously subjected to the effect of thermal gradients, which generate tensile stresses in the outside concrete layers and increase the danger of cracking. 5.5 CONSTRUCTION 5.5.1 Present s preliminary construction schedule. 5.5.2 Indicate the codes of practice that will be followed in the containment construction. 5.5.3 Indicate where and to what extent ACI 301 standard practics for construction will be exceeded, met, or not followed. l
t l l 5.5.4 Indicate the specific extent to which ASME fabrication standards will be adhered to in liner manufacturing. 5.5.5 The listing of codes should be supplemented with an additional list of codes covering items which are not covered in listed codes (Army Engineers, Bureau of Reclamation, AWS, etc.) but which may i be used as basis for applicant's specifications to contractors. i State the basis on which these supplementary, mandatory require-ments for the contractors will be prepared. 5.5.6 ASME Standards define erection tolerances in a way that is not j sufficient to ensure a satisfactory erection of the liner.. For example, they do rot cover local curvature deviations. Establish a comprehensive set of erection tolerance standards for the liner, l specifying all inaccuracies likely to occur during erection. 5.5.7 Describe in more detail the general construction procedures and sequence that will be used in construction of the containment. Include excavation, ground water control, base slab construction, I liner erection and testing, concrete construction in cylinder j and does regions, prestressing systems erection and prestressing sequence. 5.5.8 Provide a detailed description of the erection of the bottom liner. Describe the provisions that will be made to ensure a good bearing of the liner on concrete below. State if grouting will be resorted 4 to and how the liner plates will be fitted to the embedded anchors. 5.5.9 Describe the procedures for concrete placing and curing. 5.5.10 Describe the procedures for bonding between lifts. 5.5.11 Indicate the manner in which concrete lif ts will be placed and staggered. 5.5.12 Give a detailed description of the placing of concrete in the done, especially near the center portion of the done. 5.5.13 - Indicate how concrete will' be placed in zones with congested reinforcing pattern. 5.5.14 Describe the extent of concrete compression and slump testing to be used. Include the statistical basis for the proposed program and the standards for batch rejection and pour removal. 5.5.15 Indicate tne planned program for user testing of reinforcing steel for strength and ductility. Include the statistical basis for the program and the basis for reinforcing steel shipment rejection.
-13 5.5.16 Indicate the controls that will be provided to ensure that the proper specification reinforcing bars are received, at the site and, if different grades of steel are used, how errors will be avoided during construction. 5.5.17 Describe the reinforcing bar welding procedures and associated quality. control to be used in performing reinforcing bar strength welds. Include bar preparation, user verification testing for the reinforcing steel composition, maximum permissible alloy 4 specifications, temperature control provisions, radiographic and strength testing requirements, and the basis for welded splice rejection and cut-out. Will any tack welding of reinforcing steel be permitted? 5.5.18 Indicate the minimum percentage of reinforcing splices to be checked by welding inspector, using nondestructive inspection methods (X-raying, dye penetrant test, etc. ). 5.5.1 - Describe the general sequence of liner erection and testing in relationship to the structural concrete construction. 5.5.20 Indicate the controls to be employed in reference to liner plate out-of-roundness and local bulges. 5.5.21 Indicate the extent of user verification testing of certified liner NDTT properties, liner thickness, ductility, weldability, etc. 5.5.22 Indicate the applicable ASME or API code sections that will be adhered to in liner erection. i 5.5.23 Indicate the procedures and criteria for control of seas weld porosity. 5.5.24 Indicate the requirements that will be placed on seas and anchor welds to assure ductility. 5.5.25 Discuss the seem weld radin;raphy program. Also, provide an evaluation of the liner radiography with respect to providing assurance that flaws which may develop into positive leakage paths under design basia accident conditions do not, in fact, exist. 4 5.5.26 Describe the quality control procedures for liner angle and stud welding. 5.5.27 Describe those quality control procedures and standards for field welding of the liner plate that differ from the general procedures and standards, include welder qualifications, velding procedures, i i I l (~
post wela heat treatment, visual inspection, magnetic particle inspection, liquid penetrant inspection, and construction records. 5.5.28 Indicate the factory quality control requirements that will be imposed on the prestrassing system to ensure that production materials will meet design requirements and specifications. 5.5.29 Describe the corrosion protection that will be given to the prostressing wire or strand at the factory, through transportation, and in the structure prior to prestressing. 5.5.30 Describe the extent to which the tendon corrosion inhibiting wax or grease will be tested to ensure that no substances deleterious to the tendons are present. 5.5.31 Indicate the scope and extent of quality control testing of anchorage components and production anchorage assemblies, j 5.6 CONSTRUCTION INSPECTION l 5.6.1 Indicate the degree to which material preparation and construction activities will be subject to inspector surveillance. 5.6.2 Discuss the manner in which records of quality control and inspection will be kept. 5.7 TESTING AND IN-SERVICE SURVEILLANCE 5.7.1 Describe the sequence for structural testing. i 5.7.2 Describe the instrumentation program for structural testing, including: (a) Identification of structural, and liner areas to be instrumented; (b) Purpose, type, expected accuracy, and redundancy of instru-mentation; (c) The range of strains and deformations expected; (d) The protective measures that will be taken to ensure instrument performance during structural testing, considering the interval between instrument installation and its use. 5.7.3 Evaluate the extent to which the test pressure will simulate design basis accident conditions by comparing tha stresses under various test pressures with those in the structure under: (a) accident pressure plus temperature gradient, and (b) accident pressure plus i temperature gradient, plus earthque.ke, (or other combinations, if
. governing), for the following structural elements: (a) circumfer-ential reinforcing and prestressing; (b) axial (longitudinal) reinforcing and prestressing; (c) done reinforcing and prestressing; (d) base slab reinforcing; and (e) large openings. Indicate the corresponding concrete stresses. 5.7.4 By comparing stresses and strains which are experienced by the structural elements under test loadings with those calculated to exist under design basis accident loadiug, provide a discuscion in support of the selected test pressures. Include in this discussion the extent to which increased test pressure or design modifications might be considered in an effort to obtain closer test verification of structural integrity. 5.7.5 Provide a table that compares the computed stresses for two different pressure test conditions with the computed stresses due to the incident alone, and to the earthquake plus incident. The information should be sufficient to evaluate the reliability of the stress computations. Explain in detail the methods used in the preparation of this table, the physical constants employed, etc. The following points should be carefully covered: (a) Thermal stresses at large openings; evaluation of temperature gradients, stress computations for concrete and reinforcing steel, methods of combining stressed due to normal, tangential, bending, and torsional load, assumptions on cracking, stressed in stirrups, etc; (b) Prestressing; (c) Influence of shrinkage; (d) Creep; (e) Influence of liner deformations (elastic and plastic); (f) Stresses in the liner before cracking of concrete does oc' cur; and (g) Influence of transient thermal gradients.
Request for Information - Supplement No. 2 4 Sacramento Municipal Utilities District (Docket No. 50-312) April 5, 1968 5.8 Our current review indicates that the design basis earthquake (The maximum earthquake) for the Rancho Seco site should correspond to a maximum hori-zontal ground acceleration of at less 0.25g. The basis for this conclusion stems from the possibility that historical evidence may underestimate the maximum earthquake likely to occur in this province and from a need to provide both for the possible occurrence of local faults that may be unknown in this region because of the great depth of overburden and for the possible amplification in the alluvium in this geological region. You are asked to consider this basis for the design basis earthquake for the Rancho Seco site. 5.9 Provide the elevations of the proposed foundations for the containment structure, turbine buildings, and auxiliary buildings, in order that they can be compared with the boring data provided in the PSAR. 5.10 From the preliminary plans presented in the PSAR it appears that there could be relative motions between the various structures of the Rancho Seco facility. What are the calculated magnitudes of the possible relative motions between buildings and what provisions are made in the design to accommodate these relative motions in both horizontal and vertical directions ? 5.11 It is indicated on page 5.1-3 of the PSAR that the ratio of vertical to horizontal earthquake excitation will be one-half. Provide justification for the selection of this value for this particular site. 5.12 No mention is found in the PSAR as to how the vertical and horizontal earthquake stresses will be combin2d with the dead load, live load, operating loads, and accident loads. It can be inferred from statements in several sections of the PSAR that the stresses from the vertical and horizontal earthquake excitation will be added linearly and directly to other applicable loadings, but confirmation of this fact is requested. 5.13 It is noted that the containment structure will be embedded in the ground, although the depth of embedment is not precisely stated. Will the depth of embedment be such that it will be necessary to consider the interaction of ground and structure under seismic loadings ? If so, what procedures for handling this interaction will be employed? t -- v y w's w-y p-f 191 1-e
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== 5.14 It is indicated on page SA-5 of the PSAR that all Class II structures, systems, and equipment will be designed in accordance with practices which will not be less restrictive than that required by standard applicable codes or by the requirements of the Uniform Building Code. Further amplification on the procedures to be employed for the design of Class II j structures, systems, and equipment is required; and if a building code such as the Uniform Building Code is to be employed, the applicable seismic zone should be identified as well as other applicable factors relating to the design of these items. 5.15 With regard to the containment liner, it is noted that the maximum strain in the liner will be limited to one-half percent under the maximum or most severe loading conditions. It is also indicated that the buckling strength will be greater than the proportional limit. For purposes of clarification, provide the calculations leading to the buckling strength I based on the proposed liner thickness and anchorage spacing to support this value. Describe the status with regard to buckling at strains as high as one-half percent. Provide the details of fastening the liner to the anchor angles as well as a description of the provisions that are taken to insure that, under loading conditions involving accident and seismic effects, rupture or tearing of the angle is not likely. 5.16 The load combination equaticus to be employed in the design of the containment structure are listed on page 5.1-14 of the PSAR. With regard to load cochinations (b), (c), (d), and (e), provide information as to which of these expressions will be controlling for design of various j components on the basis of the design made to date. In particular, under what conditions, or alternatively at what locations, will load condition (e) control the design? 5.17 It is indicatea in the first full paragraph on page 5.1-16 of the PSAR j that the stresses from the maxioma loading condition, considering the l load factors presented, will not exceed yield strength. Further on it is noted that the strain in the liner will not exceed one-half percent. Since the wall of the structure and the liner must act together, clarifi-I cation is required as to the conditions under which the strain in the liner could approach one-half percent and still maintain the remainder of j the structure at less than yield. 1 5.18 It is noced in Section 5.1.4.6 that principal concrete tension resulting from combined membrane tension, membrane shear, and flexural tension due to _ bending moments where thermal gradients exist, will be limited to 64 ff. Provide information which will illustrate the relationship of this criterion to the criterion that the yield strength will not be exceeded in the structure under.the design load conditions. l l l i
^ 1 4 / 3 5.19 The reactor building crane must be designed to resist dislodgement during I an earthquake and, moreover, designed in such a manner as to preclude damage to any critical items that would prevent safe plant shutdown. Provide information concerning the oesign criteria selected for these cranes. 5.20 The design of the piping, reactor internals, vessels, supports and other critical equipment for seismic loading receives little attention in the PSAR. On page 4.1-6 of the PSAR it is stated that the reactor coolant system components are designated as Class I equipment and are to be designed to maintain functional integrity during earthquake, and that the basic design guide,will be AEC Publication TID-7024. Provide the loading and loading combinations applicable to the design of these elements as well as the allowable deformations for the various loading combinations. The presentation should be made in such a way that the margin of safety is clearly indicated for the various loading conditions and stresses or deformation criteria. 5.21 There are many elements of the control room instrumentation, batteries, battery racks, etc., which are Class I items and which must survive seismic motions. Provide the design criteria for these items including an evaluation of the ability of the instruments to function under conditions of tilt as well as normal seismic loadings. 5.22 The design of the on-site reservoir is described in Appendix 2G is noted to be a Class I item. Additional information is requested as to the manner in which the seismic analysis is to be made for the embankment. 5.23 From the list of Class I structures, systems, and equipment presented in Appendix 5A it is not clear whether the cooling towers or the water basins associated therewith are Class I structures and components. Provide a clarification of this point. Provide a description of the j design criteria for those parts,of the cooling system which are Class I components. 5.24 In the sketches presented in the PSAR it appears that at least one of the personnel hatches protrudes significantly beyond the containment building shell. Describe the procedures which will be incorporated in the design to insure that this structural element can not be damaged during an earthquake or otherwise cause damage to the containment system. 5.25 Describe, so far as possible at this time, the long-term surveillance program that is contemplated for this plant. _m_._,}}