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t. ATOMIC ENERGY COMMISSION* 2]* b * | WASHINGTON. O.C. 20545

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Docket No. 50-312 pg 10 9

Sacramento Municipal Utilities DistrictPost Office Box 15830Sacramento, California

Attention: Mr. E. K. DavisGeneral Counsel

Gentlemen:

Our letter of March 21, 1968 requested information on your application fora construction permit for the Rancho Seco Nuclear Generating Station. Thatrequest 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 |

facility, we have found many areas where the information was insufficient forour needs. During the course of meetings with your representatives, we haveadvised them in some detail of the nature of our concerns. In general, itwill be necessary for you to provide information relating to the basicdefinitions for the different categories of structures, provide lists ofstructures in each category, provide information on the proposed design ofall essential foundations and structures, including information on loads,load combinations, allowable atress and deformation limits, methods ofstatic and dynamic analysis, selection of materials, corrosion protectivemeasures, quality assurance And control requirements, and testing andsurveillance 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. Examplesof the kind of information needed are given in Enclosure No. 1. We wouldbe glad to discuss further any uncertainties you may have as to the typeand extent of the material required.

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Since meeting with you on March 1,1968, ue have continued discussions withour consultants on your application. Questions which have been identifiedsince our last meeting are included in Enclosure No. 2.

Sincerely yours,

cr'ef'n! rr,w yI'st:r 4. *Joms

Peter A. Morris, DirectorDivision of Reactor Licensing

Enclosures:1. Request for Information -

Supplement No. 12. Request for Information -

Supplement No. 2

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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.

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5.1.2 Describe the protection which will be provided to Class I equipmentwhich are not located in, or supported by, Class I structures.

5.1.3 State how the earthquake loads for these Class I components willbe 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 containmentand other structures will rest on layers of sands, gravels,silts, and silty clays. It is not stated whether these materialsare insensitive to accelerated weathering, or whether they expandwhen exposed to the atmosphere, during construction. Provideinformation 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 betweenexcavating and installing of foundations; how they will beprotected;

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(c) What the shape of the excavation will be; how the excavationwill be drained;

(d) The provisions that will be made to accommodate differentialsettlements during earthquakes.

5.1.7 Justify the 1 cad factors used for Class I structures other thanthe containment. Indicate design methods. Provide a list ofcodes, standards & specifications on which the design & construc-tion will be based.- Where applicable consider transient thermalgradients instead of steady state gradients.

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5.2 Containment Structural Desian

5.2.1 In certain circumstances the containment structure base may belocated below water level. It. appears that no layer of porousconcrete and no membrane water-proofing exists between the soiland the containment. Consider the possibility of cracking of theconcrete in the base mat, in the cylindrical vall and in theprestressing gallery. Ground water may reach the liner and theprestressing tendon anchors. The effect on the stability of theliner and possible corrosion of liner and tendons should beinvestigated. Explain drainage provisions at the containmentlower section.

5.2.2 Provide the following:

(a) A preliminary design drawing of the containment, presentingdetails of the base slab, done ring beam, cylinder-slab ljuncture, vertical buttresses and inspection gallery; showingreinforcing, prestressing, and liner features, includingliner anchors;

(b) Scaled load plots for moment, shear, deflection, longitudinalforce, and hoop tension, in order that an appraisal can bemade of the significance of the various loadings whichinfluence the containment design; Provide these plots as afunction 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 thermalgradients to be used in the design of the containment fortypical winter and typical summer day;

(d) The transient and staady state thermal gradients throughthe containment envelope during the design basis accident

i for typical winter and typical summer day.

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5.2.3 The thermal load from the liner is a function of the stiffness ofthe encasing concrete and its deformations. It is thereforenecessary 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- |Ieforced concrete structure. L anq,(/c fore i

ldifferent elevations and explain their use in the design of theconcrete shell and in thermal liner loading computations. Includethe effect of shrinkage and creep.

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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 linersteel. Thh thickness of the two adjacent liner plates may vary,

' by as such as 10%. In addition, only the minimum yield point isindicated in PSAR, but not the maximum yield point, which maydiffer from the minimum by as much as 25% - 30%. Explain howthe variations of thickness and yield point are considered inthe 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, consideringthat the structure is not axisynetric (buttresses);

(b) The considerations given to, and the analytical proceduresfor determining discontinuity stresses at the base, at thedone (ring girder), and at the buttresses; the assumptions I

with regard to structural stiffness that form the basis forthese stress determinations; the variations of E ande econsidered.

5.2.6 It is not clear whether the computer program which is used forthe design will take into account the cracking of concrete, and

the resulting variation of E anq,6( e. Should not the programealso be able to handle loadings that are not axisynetric whichact 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 justificationfor this approach.

5.2.8 Indicate whether the following has been considered:

(a) Possible reversal of stresses, due to creep during coldshut down;

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(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 thewall.

5.2.9 For the loadings of the base slab, describe the analytical proced-ures used to arrive at the forces, moments, and shears, consideringloading 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 stresslimits by describing the extent to which liner participation isrelied 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 effecton the liner. Consider possible cracking of concrete.

5.2.12 Explain whether one-third increase in allowable stresses will beused. This increase in allowable stresses is not considered inkeeping with its usage in normal practice, particularly withrespect to the D + L + S t T loadf.ng. Discuss this problem andprovide a criterion that consides biaxial and triaxial loading ,

|effects. Justify the values of shear (as a measure of beam strengthin diagonal tension) for a structure of this type. Discuss your |design criteria in this area, keeping in mind possible biaxialtension stresses, and two-dimensional cracking.

5.2.13 Under incident conditions concrete may be cracked and the crack l

pattern may be two-dimensional. Explain how, under this condition, i

the radial, vertical, and tangential shears are transferred I

through the section.

5.2.14 The reinforcing steel may be stressed to the yield point. "Thisstress 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, tothermal stresses and during an accident, the problem,of adequatebar 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 discontinuitystresses, some diagonal bars,. bars connecting the buttresses tomain shell, bars under prestressing anchors, etc? i

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!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 |

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at a loading distribution on the containment structure.,

(b) The order of magnitude of lateral earth pressure under seismicloading and indicate how such loading will be factored intothe containment design.

(c) The manner in which damping will be considered in thestructural design. In this description, justify the dampingvalues 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 howthe corresponding damping values will be included. Describe

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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 theEl Centro spectrum. Indicata the degree to which this scalingwas 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 toliner buckling, and the safety factors provided. Includethe influence of large tangential strains due to possibleopening and closing of cracks in concrete;

(b) The geometrical pattern, type, and spacing of liner accach-ments; and the analysis procedures, boundary conditions, andresults with respect to buckling under the loads cited above;

(c) Tolerance on liner plate thickness and liner yield strengthvariation and their bases;

(d) The possibility of both types of buckling; elastic andinelastic . In this study, discuss the influence of allpertinent 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);

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Ground water infiltration, and back pressure, earthquake,temperature loading, vacuur loading; and

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5.2.19 Provide information on:

(a) The stress and strain limits used for the liner, the basesfor these 10mits, and the extent to which these limits relateto liner leakage;

(b) The type, character, and magnitude of cyclic loads for whichthe containment liner will be designed, including a discussionof earthquake cycling;

(c) The analytical procedures and techniques to be used in lineranchorage design, including sample calculations; and

(d) The failure mode and failure propagation characteristics ofanchorages. Discuss the extent to which these character-istics influenca leak tightness integrity. What designprovisions will be incorporated to prevent anchorage failuresfrom jeopardizing leaktight integrity?

5.2.20 Por the design of the anchors, elastic and inelastic buckling ofthe liner should be considered as well as the different modes ofbuckling of adjacent plates. Consider, for the design of theanchors, the possibility of unbalanced loads acting on severalanchors. The study should prove that no chain reaction canoccur 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 withoutcracking?

5.2.22 Describe the design approach that will bn av>.J where loadings mustbe transferred through the liner such as at crane brackets ormachinery equipment rounts; provide typical design details andcomputations.

5.2.23 It is noted that the bottom liner is not accessible for inspectionduring the life of the plant. It is therefore vary important toavoid any unrecessary stresses and strains in the bottom liner.The arrangement for load transfer through the liner under thebottom of the interior structure should provide for transferof shears carallel to the liner. Indicate how the shears,especially those due to thermal expansion and earthquake, willbe accammodated. *

5.2.24 Provide the latsat liner arrangement to be used at the base-cylinder to liner juncture, the strain limits imposed at'thejuncture, and an analysis of the capability of the chosen linercrrangement to absorb these strains under the design basisaccident and earthquake conditions. Discuss the influence oflocal cracking on liner anchors.

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5.2.25 Describe the analytical procedures for analysis of liner stressesaround openings. Also, provide the method of liner design toaccommodate these stresses and the related stress limits. Justifythe proposed thickening of the liner at penetrations. Discussthe liner anchors at this location.

5.2.26 A general statement that all penetrations will be anchored intothe concrete wall and that the anchorage will develop at leasttne plastic strength of the penetration sleeve would not besatisfactory if not followed by an explanation what plasticstrength is meant. Provide this explanation in terms of thetension, bending, shear, and combined components.

5.2.27 With regard to penetration design, describe:

(a) The design criteria to be applied to ensure that pipingloads under the postulated design basis accident whichcould result in pipe rupture or relative displacement ofthe internal systems relative to the containment, asubsequent pipe rupture due to torsional, axial, bending,or shear, will not cause a breach of the containment.Also, include the detailed design criteria with respectto pipe rupture between the penetration and containmentisolation valves. These piping sections represent anextension of the containment boundary under a conditionwhen isolation is required. What codes will be used?Provide typical designs to illustrate how the criteriaare applied.

(b) The extent to which the penetrations and their surroundingliner regions will be subjected to vibratory loading frommachinery attached to the piping systems. Indicate how theseloads 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

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loss of thermal protection would have on the containment's i

structural and leak-tightness characteristics. What jtherpal gradients are used?

(d) The manner in which axial stresses, hoop stresses, shearstresses, bending stresses (in two directions) and shearstresses 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 '

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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-PowerPiping, B31.1.0-1967 will be used for all loading cases. Willfactored load combinations be used with this code?

5.2.28 Provide criteria with regard to opening sizes that constitutelar5e Openings; hence, meriting special design consideration.List the number and indicate the size of the large openings forthe containment.

5.2.29 Add the following information:

(a) For all penetrations, indicate the criteria for the bendingof reinforcing bars which have to clear the openings.Maximum slope and minimum bending radius to avoid localcrushing of concrete should be shown.

(b) For penetrations greater than about 9 inches and up to andincluding about 4 feet, explain how normal, shear, bending,and torsional stresses are covered by the prestressing andby the reinforcing bars.

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(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 biaxialtension, and cracked in two directions.

5.2.30 With respect to large opening design, describe:

(a) The primary, secondary, and thermal loads that will beconsidered in the design of the openings, and how they were4

established;

(b) The stress analysis procedures that will be used in design;

(c) The method that will be followed for the design; the workingstress design method or the ultimate strength design method,or both; If the ultimate strength design method is used, thefactored load combinations should be given together withcorresponding capacity reduction factors;

(d) How the existence of biaxial tension in concrete (cracking)will be taken care of in the design; How the normal andshear stresses due to prestressing, to axial load, two-directional shear, and torsion, will be combined; Clarifythese points and establish criteria for the design of thethickened part of the wall around the opening (ring girder).

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. Reference to recent pressure tests of similar openings would

| . not be conclusive, since the thermal sad earthquake loadswere not applied during tests, and since these tests have notestablished 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 partof the shell, around large openings and its effect on theshell; Include prestressing, creep and shrinkage. Thecomparison with stresses in a circular flat plate would notbe convincing, since it eliminates one of the most importanteffects, i.e. the effect of torsion. Present a method whichchecks torsional stresses.

(f) Additional information on reinforcing pattern,. i.e. , rebersize and spacing, and prestressing pattera that will beused around large openings;

(g) The safety factor provided in design at Isrge openings;Sample computations should be provided, listing all thecriteria and analyzing the effect of all pertinent factorssuch as prestressing, cracking, etc.

5.2.31 List the spectrum of external missiles that the containment willbe designed to withstand and the procedures to be used in checkingthe containment design to withstand such missile hazards.

5.2.32 If insulation is required, present a detailed study of it. Designrequirements and performance specifications should be included toprovide confidence that the insulating qualities will be achieved

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under accident conditions. Hence, provide a description of:

(a) The specified and tolerable temperature rise in the linerand the design safety factor provided on insulatingperformance;

(b) Means provided for fastening the insulating material to thebacking liner and for precluding steam channeling in back'

of the insulation (from the top or through joints) and statewhether the insulating panels be removable;,

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(c) An analysis of the consequences of one or more insulationpanels being displaced from the liner during, or as aconsequence of, an accident situation;

(d) The consideration given to increased conductivity due to:

! humidity and compression during accident pressure transientsand precompression from structural and leakage testing;

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(e) The consideration that will be given to the compatibility ofthe insulation and liner.

5.2.33 Provida a description of the procedures used for analyzing anchoragezones and provide typical results of such analyses. Includeconsideration of biaxial tension in concrete.

5.2.34 Provide typical details of anchorage zone reinforcing. Provideinformation that support its adequacy to resist the imposedanchorage 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 providedin the containment shell for crack control, considering possiblereversal of stresses during cold shut-down.

5.3 MATg11ALS

5.3.1 Justify the type cement to be used, explain the bas,is for itsselection, and describe the user verification testing to beperformed.

5.3.2 Indicate the specifications to be used for the concrete aggregateand indicate the testing to be performed to assure the suitabilityof the selected aggregate. Indicate the specifications to beapplied 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 andextent of testing of trial mixes. Indicate the type and extentof admixtures which may be used. Describe their purposes, theirextent of compliance to ASTM specifications, and their testing.Describe the choice of slump values and list them. |

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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 willbe made by welding. State the location of these welds.

5.3.6 Add the description of the " splicing" of inclined bars, orhorizontal stirrups provided to take the radial shears in thewalls, with the vertical bars. If the " splicing" is done bylapping the diagonal bar with a vertical bar, or by bendingthe stirrup around a vertical bar, demonstrate that, despitebiaxial tensile stresses in concrete and vertical and horizontalcrack pattern, the load in the diagonal bars or stirrups can

| safely be transmitted to the vertical bars.!

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5.3.7 Specify quality control for the strength welds of reinforcing barsto structural elements such as plates, rings, sleeves, and foroccasional 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.

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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 forthe 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 consideredand is being provided. State whether soil resistivity surveys havebeen conducted'and, if so, provide the results.

5.4.3 Discuss the extent to which protective coatings will be appliedto 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 concretelocated at base. Also no provision has been made for a porouslayer at the cylindrical wall of the containment. Justify theomission 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, whichgenerate tensile stresses in the outside concrete layers andincrease 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 thecontainment construction.

5.5.3 Indicate where and to what extent ACI 301 standard practics forconstruction will be exceeded, met, or not followed.

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|! 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 mayi

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. . Forexample, they do rot cover local curvature deviations. Establisha comprehensive set of erection tolerance standards for the liner,-

| specifying all inaccuracies likely to occur during erection.

5.5.7 Describe in more detail the general construction procedures andsequence that will be used in construction of the containment.

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; 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 bearingof the liner on concrete below. State if grouting will be resorted4

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 andstaggered.,

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5.5.12 Give a detailed description of the placing of concrete in thedone, especially near the center portion of the done.

5.5.13 - Indicate how concrete will' be placed in zones with congestedreinforcing pattern. |

|5.5.14 Describe the extent of concrete compression and slump testing to |

be used. Include the statistical basis for the proposed programand the standards for batch rejection and pour removal.

|5.5.15 Indicate tne planned program for user testing of reinforcing steel I

for strength and ductility. Include the statistical basis for the ;

program and the basis for reinforcing steel shipment rejection. |!

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'5.5.16 Indicate the controls that will be provided to ensure that the

proper specification reinforcing bars are received, at the siteand, if different grades of steel are used, how errors will beavoided during construction.

5.5.17 Describe the reinforcing bar welding procedures and associatedquality. control to be used in performing reinforcing bar strengthwelds. Include bar preparation, user verification testing forthe reinforcing steel composition, maximum permissible alloy4

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 bechecked by welding inspector, using nondestructive inspectionmethods (X-raying, dye penetrant test, etc. ).

5.5.1 - Describe the general sequence of liner erection and testing inrelationship to the structural concrete construction.

5.5.20 Indicate the controls to be employed in reference to liner plateout-of-roundness and local bulges.

5.5.21 Indicate the extent of user verification testing of certified linerNDTT properties, liner thickness, ductility, weldability, etc.

5.5.22 Indicate the applicable ASME or API code sections that will beadhered to in liner erection.

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5.5.23 Indicate the procedures and criteria for control of seas weldporosity.

5.5.24 Indicate the requirements that will be placed on seas and anchorwelds to assure ductility.

5.5.25 Discuss the seem weld radin;raphy program. Also, provide anevaluation of the liner radiography with respect to providingassurance that flaws which may develop into positive leakage

! paths under design basia accident conditions do not, in fact,exist.

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5.5.26 Describe the quality control procedures for liner angle and studwelding.

5.5.27 Describe those quality control procedures and standards for fieldwelding of the liner plate that differ from the general proceduresand standards, include welder qualifications, velding procedures,

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post wela heat treatment, visual inspection, magnetic particleinspection, 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 productionmaterials will meet design requirements and specifications.

5.5.29 Describe the corrosion protection that will be given to theprostressing 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 waxor grease will be tested to ensure that no substances deleteriousto the tendons are present.

5.5.31 Indicate the scope and extent of quality control testing ofanchorage components and production anchorage assemblies,

j 5.6 CONSTRUCTION INSPECTION|

5.6.1 Indicate the degree to which material preparation and constructionactivities will be subject to inspector surveillance.

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5.6.2 Discuss the manner in which records of quality control and I;

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 beinstrumented;

(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, consideringthe interval between instrument installation and its use.

5.7.3 Evaluate the extent to which the test pressure will simulate designbasis accident conditions by comparing tha stresses under varioustest pressures with those in the structure under: (a) accidentpressure plus temperature gradient, and (b) accident pressure plus

i temperature gradient, plus earthque.ke, (or other combinations, if

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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 thecorresponding concrete stresses.

5.7.4 By comparing stresses and strains which are experienced by thestructural elements under test loadings with those calculated toexist under design basis accident loadiug, provide a discuscion insupport of the selected test pressures. Include in this discussionthe extent to which increased test pressure or design modificationsmight be considered in an effort to obtain closer test verificationof structural integrity.

5.7.5 Provide a table that compares the computed stresses for two differentpressure test conditions with the computed stresses due to theincident alone, and to the earthquake plus incident. The informationshould be sufficient to evaluate the reliability of the stresscomputations. Explain in detail the methods used in the preparationof this table, the physical constants employed, etc. The followingpoints should be carefully covered:

(a) Thermal stresses at large openings; evaluation of temperaturegradients, stress computations for concrete and reinforcingsteel, methods of combining stressed due to normal, tangential,bending, and torsional load, assumptions on cracking, stressedin 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 doesoc' cur; and

(g) Influence of transient thermal gradients.

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|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 maximumearthquake) for the Rancho Seco site should correspond to a maximum hori-zontal ground acceleration of at less 0.25g. The basis for this conclusionstems from the possibility that historical evidence may underestimate themaximum earthquake likely to occur in this province and from a need toprovide both for the possible occurrence of local faults that may be unknownin this region because of the great depth of overburden and for the possibleamplification in the alluvium in this geological region. You are asked toconsider this basis for the design basis earthquake for the Rancho Seco site.

5.9 Provide the elevations of the proposed foundations for the containment I

structure, turbine buildings, and auxiliary buildings, in order that theycan be compared with the boring data provided in the PSAR.

5.10 From the preliminary plans presented in the PSAR it appears that therecould be relative motions between the various structures of the Rancho |Seco facility. What are the calculated magnitudes of the possible relativemotions between buildings and what provisions are made in the design toaccommodate these relative motions in both horizontal and verticaldirections ?

5.11 It is indicated on page 5.1-3 of the PSAR that the ratio of vertical tohorizontal earthquake excitation will be one-half. Provide justificationfor the selection of this value for this particular site.

5.12 No mention is found in the PSAR as to how the vertical and horizontalearthquake 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 andhorizontal earthquake excitation will be added linearly and directly toother 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 depthof embedment be such that it will be necessary to consider the interactionof ground and structure under seismic loadings ? If so, what proceduresfor handling this interaction will be employed?

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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 whichwill not be less restrictive than that required by standard applicablecodes or by the requirements of the Uniform Building Code. Furtheramplification on the procedures to be employed for the design of Class II

j structures, systems, and equipment is required; and if a building codesuch as the Uniform Building Code is to be employed, the applicable seismiczone should be identified as well as other applicable factors relatingto the design of these items.

5.15 With regard to the containment liner, it is noted that the maximum strainin the liner will be limited to one-half percent under the maximum or ,

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most severe loading conditions. It is also indicated that the bucklingstrength will be greater than the proportional limit. For purposes ofclarification, provide the calculations leading to the buckling strength I

based on the proposed liner thickness and anchorage spacing to supportthis value. Describe the status with regard to buckling at strains ashigh as one-half percent. Provide the details of fastening the liner

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to the anchor angles as well as a description of the provisions that '

are taken to insure that, under loading conditions involving accidentand seismic effects, rupture or tearing of the angle is not likely.

5.16 The load combination equaticus to be employed in the design of thecontainment 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 1

which of these expressions will be controlling for design of various jcomponents on the basis of the design made to date. In particular, under I

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 isnoted that the strain in the liner will not exceed one-half percent.

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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 jthe structure at less than yield. 1

5.18 It is noced in Section 5.1.4.6 that principal concrete tension resultingfrom combined membrane tension, membrane shear, and flexural tension dueto _ bending moments where thermal gradients exist, will be limited to

64 ff . Provide information which will illustrate the relationship ofthis criterion to the criterion that the yield strength will not beexceeded in the structure under.the design load conditions.

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; 5.19 The reactor building crane must be designed to resist dislodgement duringI 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

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cranes.

5.20 The design of the piping, reactor internals, vessels, supports and othercritical equipment for seismic loading receives little attention in thePSAR. On page 4.1-6 of the PSAR it is stated that the reactor coolantsystem components are designated as Class I equipment and are to bedesigned to maintain functional integrity during earthquake, and thatthe basic design guide ,will be AEC Publication TID-7024. Provide theloading and loading combinations applicable to the design of theseelements as well as the allowable deformations for the various loadingcombinations. The presentation should be made in such a way that themargin of safety is clearly indicated for the various loading conditionsand 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 surviveseismic motions. Provide the design criteria for these items includingan evaluation of the ability of the instruments to function underconditions of tilt as well as normal seismic loadings.

5.22 The design of the on-site reservoir is described in Appendix 2G is notedto be a Class I item. Additional information is requested as to themanner 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 inAppendix 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 jdesign criteria for those parts,of the cooling system which are Class Icomponents.

5.24 In the sketches presented in the PSAR it appears that at least one ofthe personnel hatches protrudes significantly beyond the containment

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building shell. Describe the procedures which will be incorporated in '

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the design to insure that this structural element can not be damagedduring an earthquake or otherwise cause damage to the containment system.

5.25 Describe, so far as possible at this time, the long-term surveillanceprogram that is contemplated for this plant.

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