ML19319C274

App 5A to Davis-Besse PSAR, Design Bases for Structures,Sys & Equipment.

ML19319C274
Person / Time
Site:	Davis Besse
Issue date:	08/01/1969
From:	TOLEDO EDISON CO.
To:
References
NUDOCS 8002110747
Download: ML19319C274 (12)

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D-B APPENDIX 5A

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DESIGN BASES FOR STRUCTURES, SYSTEMS AND EQUIPMENT 1 GENERAL The design bases for structures for normal operating conditions are governed by the applicable building codes. The design bases for specific systems and equipment are stated in the appropriate PSAR Section. The basic design cri-terion for the design basis accident and seismic conditions is that there be no loss of function if that function is related to public safety.

The design of structures and facilities conforms but is not limited to the applicable codes and specifications listed below.

1. Unifor= Building Code (UBC), 1967 Edition.

2. American Institute of Steel Construction (AISC) " Specification for the Design, Fabrication and Erection of Structural Steel for Buildings" - Sixth Edition.

3. American Iron and Steel Institute (AISI) " Specification for the Design of Light Gage Cold-formed Steel Structural Members" -

1961 Edition.

h. American Concrete Institute (ACI) " Building Code Requirements for Reinforced Concrete" - (ACI-318-63 and ACI-318-70). l8 5 American Welding Society (AWS) " Standard Code for Arc and Gas Welding in Building Construction" - (AWS D1.0-66 and AWS D12.1-61)

6. API Specification No. 620 & 650 for Welded Steel Storage Tanks.

7 American National Standards Institute, B 96.1 - 1967 "Scecification 3

for Aluminum Alloy Tanks".

8. ASME Boiler and Pressure Vessel Code,Section III, Nuclear Vessels, Class B, governs the design and fabrication of the containment vessel and penetrations.

9 AEC Publication TID 702h " Nuclear Reactor and Earthquakes" -

governs the seismic design of all Class I structures.

10. American Society of Civil Engineers (ASCE) Paper No. 3269,

" Wind Forces cn Structures" - governs vind design requirements,

11. American Association of State Higavay Officials (AASHO)

" Standard Specifications for Highway Bridges" - Ninth Edition 1965

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12. Nuclear Enerrf Frenerty Insurance Association - Mutual Atomic Enerzy Reinsurance Pool (NEPIA - MAERP), Basic Fire Protection for Nuclear Power Plants.

_ 13 American Concrete Institute (ACI) " Specification For the Design and Construction of Eeinforced Concrete Chimneys" - (ACI-307-69). 3 5A-1 Am ndment No. 8

D-B 2 CLASSES OF STRUCTURES, SYSTEMS AND EQUIPMENT CLASS I Class I structures, systems and equipment are those whose failure could cause uncontrolled release of excessive amounts of radioactivity or tnose essential for immediate and long-term operation following a design basis accident. When a system as a whole is referred to as Class I, portions not associated with loss of function of the system are designated as Class II.

The following is a table of Class I structures, their seismic analysis classification and loadings:

• General Type of Loadings Structures Seismic Analysis Earthquake Tornado Missile .

CONTAINMENT BUILDING 5

Shield Building Type I and II X X X Containment Vessel Type I and II X X Containment Penetrations Type II X X Containment Interior Type I and II X X Structures AUXILIARY BUILDING Exterior Structure Type I X X X Interior Structures Type I X X Penetration Rooms Type I and II X X X Station Control Room Type I and II X X X Spent Fuel Storage Pool Type I X X X Transfer Tubes Type I and II X Cable Spreading Room Type I X Switchgear Rooms Type I X X X -

Diesel Generator Rooms Type I X X X Station Battery Room Type I X X X Class I Equipment Supports Type II X

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IliTAKE STRUCTURE Concrete Substructure Type I and II X X Service Water Pumps Enclosure Type I X X Service Water Pipe Type I X Tunnel 5

Class I Equipment Type II X Supports YARD STRUCTURES Borated Water Storage Tank Type I X l Tank Foundation Type I and II X** X Diesel Fuel Storage Tank Type I X Tank Foundation Type I and II X** X Condensate Storage Tank Type I X**

Foundation

" Earthquake Analysis Type I - Respense Spectrum Analysis Type II - Time History Response Spectrum Analysis

• • 0nly 50% of Tornado Forces on Tank Shells The following are Class I equipment and systens:

Reactor vessel and internals including control rods and control rod drives.

Reactor coolant system components (steam-generators, pressurizer, pumps, etc.) and interconnecting piping and supports.

All piping and connections to the primary system to and including the second isolation valve.

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5A-2a Amendment No. 5 l

D-B Containment isolation valves and penetrations

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s-Main stesn and feedvater piping from generator to and including the isolation valve Atmospheric dump and main steam safety valves and associated piping Auxiliary feedvater pumps and system Fuel storage facilities including spent fuel and new fuel storage equipment 2

Diesel generator system Containment vessel crane (unloaded condition)

Station battery system .

Emergency buses and other electrical gear to and including power equipment required for safe shutdown Service water system, parts which service Class I systems Component cooling water system serving vital NSS heat exchange equipment

! Containment spray system Containment air recirculation and cooling units Lov presaure injection and residual heat removal system Core flooding system 2

Makeup system 2

High-pressure injection system Condensate storage tank (except tornado, turbine missiles and collapse of Class II structures).

5 NOTE: The figures showing the interfaces between the Class I and II systems have been submitted in answer to the question 1.3. These figures show the components of the systems and the seismic class to which they are designed. -

CLASS II Class II structures, systems and equipment are those whose failure would not I result in the release of radioectivity and would not prevent reactor shutdown.  ;

The failure of Class II structures, systems and equipment may interrupt power l generation.

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l Amendment No. 5

D-B Class I equipment and systems located in Class II structures have reinforced concrete enclosures designed to withstand the loads for Class I structures.

3 DESIGN BASES All steel structures are designed by the Working Stress Method. All major reinforced concrete structures are designed by the Ultimate Strength Method.

4 NOTATIONS U = Required ultime.te load capacity.

D = Dead load of structure and equipment plus any other permanent loads contributing stresses, such as soil or hydrostatic loads.

An allowance is also made for future pemanent loads.

L = Live load and piping loads.

R = Force or pressure on structure due to rupture of any one pipe.

T g = Themal loads due to temperature gradient through vall under operating conditions.

H = Force on structure due to thermal expansion of piIses under operating conditions.

TA= Themal loads due to temperature gradient through wall under accident conditions.

HA = Force on structure due to themal expansion of pipes under accident conditions.

E = " Maximum Probable (Smaller) Earthquake" resulting frem ground surface acceleration of 0.08g. 2 E'= " Maximum Possible (Larger) Earthquake" resulting from ground surface acceleration of 0.15g.

W = Wind load. (Wind velocity 90 mph at 30 ft above ground.) See ASCE 3269 for increase due to gusts and height.

W'=. Tornado load including differential pressure.

@ = Capacity reduction factor. (Defined in ACI-318-63 Code, Section 150h.) See Appendix 5D for discussion.

f s= A11ovable stress for structural steel. (Defined in AISC, Section 1 5)

F = Yield strength for steel.

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5A-3a Amendment No. 3

D-B 5 SEISMIC ANALYSIS For seismic loads, Class I structures and components are designed using the

" Response Spectrum Curves" shown in Figures III-5 and III-6 of Appendix 2C. Seismic accelerations are determined on the basis of dynamic analysis.

When structures or components are adequately represented by a single degree of freedom model the maximum value c' the response curve for the appropriate damping factor may be used in lieu of performing a dynamic analysis.

Complex structures and components which require multi-degree of freedom analysis for adequate representation vill be analyzed by modal techniques similar to those described in Section 5.0.2.3.8.

Damping factors to be used in determ'ning response acceleration as shown in Table 5A-1.

The damping values associated with a stress level of "0 5 times yield point"

• will be used i.T analysing the structures, components and equipments. The damping values 2% and h% for the maximum probable and maximum possible 6 earthquake will be used in reinforced concrete structures and 1% and 2%

damping values will be used for the pipings and velded steel respectively.

The damping values associated with 0.25Fy and 1.0Fy will not be used in the analysis N

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0345 Amendment No. 6 5A-h

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TABLE 5A-1 PERCENTAGE OF CRITICAL DAMPING FACTORS Type and Condition of the Structure Stress Level

,w Vital Welded Bolted and/or Reinforced Reinforced Prestressed Prestressed Piping Piping Steel riveted steel Concrete Concrete Con: rete Concrete Max. Prob. Max. Poss. Max. Prob. Max. Poss.

Earthquake Ibrthquake Earthquake Earthquake Belov 0.25 0.5 05 1.0 1.0 1.0 1.0 times yield point (no joint ( no crack-slip) ing) t2 tn 3

m About 0 50 1.0 1.0 2.0 50 2.0 h.0 2.0 times yield point (slight (consider- (slight cracking) able crack- crack-ing) ing)

At or just P0 2.0 50 10.0 70 10.0 5.0 7.0 below yield point (Partial ( no pre-prertress stress left) left)

Beyond 50 70 20.0 10.0 15 0 10.0 15 0 C.0 g3 yield point C*)

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D-B l

Class II structures are designed in accordance with design methods of referenced codes and standards, with prudent engineering practice, and in

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accordance with applicable codes. The area is in Seismic Zone No.1 (UBC- l 1967).

6 DESIGN PROCEDURES

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6.1 CLASS I STRUCTURES, SYSTEMS AND EQUIPMENT I 6.1.1 DURING NORMAL OPERATION For loads encountered during normal station operation, Class I structures, systems and equipment are designed in accordance with design methods of referenced codes and standards. Seismic design is in accordance with Section 5 6.1.1.1 Concrete Reinforced concrete structures are designed for ductile behavior, whenever  ;

possible; that is, with steel stresses controlling. '

Design of concrete structures shall satisfy the most severe loading combina-tions, based on the load factors shown below:

U = 1.5 D + 1.8 L N

! U = 1.25 (D + L + Hg + E) + 1.0 T o ,)

l U = 1.25 (D + L + Ho + W) + 1.0 To j U = 0 9 D + 1.23 (Ho + E) + 1.0 T o U = 0 9 L + 1.25 (Hg + W) + 1.0 To l In addition, for ductile moment resisting concrete space frames, shear walls l l

and braced frames: l U = 1.4 (D + L + E) + 1.0 T + 1.25 Ho l l

U = 0.9 D + 1.25 E + 1.0 To + 1.25 Ho l l

l For structural elements carrying mainly earthquake forces, such as equipment supports:

U = 1.0 D + 1.0 L + 1.8 E + 1.0 To + 1.25 H e i 6.1.1.2 Yield Cacacity Reduction Factors k The yield capacity of all load carrying structural elements vill be reduced  !

by a yield capacity reduction factor (Q) as given below. The justification )

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( for these numerical values is given in Appendix SD. This factor vill provide for the possibility that small adverse variations in material strengths, workmanship, dimensions, control, and degree of supervisien while individually within required tolerance and the limits of good practice, occasionally =ay combine to result in undercapacity.

Yield Capacity Reduction Factors:

@- = 0.90 for concrete in flerare.

= 0.85 for diagonal tension, bond, and anchorage in concrete.

= 0.75 for spirally reinforced concrete co=pression members.

= 0.70 for tied compression members.

= 0.90 for fabricated structural steel.

@ = 0.90 for reinforcing steel in tension (excluding splices).

@ = 0.90 for reinforcing steel in tension with mechanical splices.

6.1.1.3 Structural Steel Steel structures shall satisfy the following leading combinations without exceeding the specified stresses:

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a. D + L.................................... Stress Limit = fs b.

D+L+To+Ho + E...................... Stress Limit = 1.25 f s

c. D+L+T +H o + W...................... Stress Limit = 1.33 f s In addition, for structural elements, carrying mainly earthquake forces, such as struts and bracings:

D+L+To + Ho.+ E...................... Stress Limit = fs 6.1.2 DURING ACCIDENT AND MAXIMUM POSSIBLE ' LARGER)~ EARTHQUAKE CONDITIONS The Class I structures, systems and equipment are in general proportioned to maintain elastic behavior when subjected to various combinations of dead loads, thermal loads, seismic and accident loads. The upper limit of elastic behavior is considered to be the yield strength of the effective load-carrying struc-

. tural materials. The yield strength Fy for steel (including reinforcing steel) is considered to be the guaranteed minimum given in appropriate ASTM specifications. The yield strength for reinforced concrete structures is considered to be the ultimate resisting capacity as calculated from the

" Ultimate Strength Design" portion of the ACI-318-63 code.

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D-dil 6.1.2.1 Concrete M -

Concrete structures shall satisfy the most severe of the following loading combinations:

Ur 1.0 D + 1.0 L + 1.25 E + 1.0 Tg + 1.0 HA + 1.0 R 3 '

U = 1.0 D + 1.25 E + 1.0 Tg + 1.0 Hg + 1.0 R U = 1.0 D + 1.0 L + 1.0 E' + 1.0 T, + 1.25 Ho + 1.0 R U = 1.0 D + 1.0 L + 1.0 E' + 1.0 7A + 1.0 Hg e l.0 R U = 1.0 D + 1.0 L + 1.0 W' + 1.0 To + 1.25 H o 6.1.2.2 Structural Steel Steel structures shall satisfy the most severe of the following leading combinations without exceeding the specified stresses:

a.

D+L+R+To + Ho + E'.................. Stress Limit' = 1.5 fs b.

D+L+R+FA+HA + E'.................. Stress Limit' = 1.5 f, c.

D+L+I+To + Ho ....................... Stress Limit' = 1.5 f3

• Maximum alleva" stress in bending and tension is 0.9yF . M M - allowable \

stress in shesc. ,05F. j 7

Stress in some of the materials may exceed yield strength. If this is the case, an analysis shall be made to determine that the entrgy absorption capacity of the structure exceeds the energy input. The resulting deflection or distortion shall be reviewed. The containment structure and engineered safety features system components are protected by barriers- from all credible 1 l missiles erosion which might be generated from the primary system. Local yielding or of barriers is permissible due to jet or missile impact, provided there is no general failure.

The final design of the missile barrier and equipment support structures inside the containment vill be reviewed to assure that they can withstand applicable pressure loads, jet forces , pipe reactions and earthquake loads without loss of function. The deflections or deformations of structures and supports vill be checked to assure that the functions of the containment and engineered safety features equipment are not impaired.

6.2 CLASS II ST'RUCTURES, SYSTD4S AND EQUIPMENT 6.2.1 CONCRETE Load factors and combinations as specified shall apply. All other design, 1 except load factors and combinations, shall be as specifi v in the ACI Standard 318-63 Significant thermal loads shall be included. The following load factors i and combinations shall be used for ductile mcment resisting space frames and s shear valls:

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Amendment No. 3 5A-8 M 0349,

D-B U = 1.h (D + L + E) + 1.0 To + 1.25 H9 U = 0.9 D + 1.25 E + 1.0 To + 1.25 H g 6.2.2 STRUCTURAL STEEL Steel structures shall satisfy the following loading combinations without exceeding the specified stresses:

a. D + L..................................... Stress Limit = f s b.

D+L+To+Ho + E....................... Stress Liuit = 1.33 f,

c. D+L+T o +Ho + W.......... ............ Stress Limit = 1.33 r s

6.3 CLASS I SYSTFMS AND EQUIPMENT DESIGN All Class I systems and equipment are designed to the standards of the applicable Code. The loading combinations which are employed in the design of Class I systems and equipment are given in Table 5A-2.

Table 5A-2 also indicates the stress limits which are used in the design of the listed equipment for the various loading combinations.

To perform their function, i.e., allev core shutdown and cooling, the reactor vessel internals must satisfy deformation limits which are more restrictive than the stress limiu shown on Table SA-2. For this reason the reactor vessel internals are treated separately.

6.3.1 PIPING AND VESSELS The reasoning for selection of the load combinations and stress limits given in Table SA-2, is as follows: For the maximum probable (smaller) eartcquake, the nuclear steam supply system is designed to be capable of continued safe operation, i.e. , for the combination of normal loads and maximum probable (smaller) earthquake loading. Critical equipment needed for this purpose is required to operate within normal design limits.

In the case of the maximum possible (larger) earthquake, it is only necessary to ensure that critical components do not lose their capability to perform their safety function, i.e., shutdown the station and maintain it in a safe condition. This capability is ensured by maintaining the stress limits as shown in Table 5A-2.

For the extremely remote event of simultaneous occurrence of maximum possible (larger) earthquake and reactor coolant system pipe rupture, the design of ,

Class I pipe and components, excluding the broken pipe, is checkad for no loss of function, i.e. , the capability to e ntain fluid and allow fluid flow.

This is assured by limiting the various stress combinations within the limits shown in line 3 in Table'5A-2.

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D-B 6.3.2 MOVEMENT OF REACTOR COOLANT SYSTEM COMPONENTS O >

The criterien for =ovement of the reactor vessel, under the worst combination of load, i.e., normal plus the maximum possible (larger) earthquake plus reactor coolant pipe rupture loads, is that the radial movement of the reactor vessel vill not exceed the clearance between a reactor coolant pipe and the surrounding concrete to prevent excessive shear load on the reactor coolant system pipe, should this limit be more restrictive than those listed in Table 5A-2.

The realtive motions between reactor coolant system components will be controlled by the structures which are used to support the reactor vessel, the steam-generators, the pressurizer and the reactor coolant pumps in such a way that the stresses in the various components and pipes do not exceed the limits as establ ched *n Table 5A-2.

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5A-10

• ;3 TABLE 5A-2 LOADING COMBINATIONS AND STRESS LIMITS LOADING LOADING STRESS LIMITS CASE COMBINATIONS Vessels Reactor Vessel Piping Supports

__ (Ref. Section 4.0) Internals CASE I Design Loads & Pm 1 1.0 Sm Pm 1 1.0 Sm Py 1 1.2 Sh Maximum Probable Working (Smaller) Earth- Py+Pb 1 1*5 8 m Py+Pb 1158 m Py+Pb 1 1.2 Sh Stress quake CASE II Design Loads + P, 1 1.2 S, P, 1 2/3 Su Maximum Possible Pm i 1.2 Sh Within (Larger) Earth- Py+Pb 1 1.2 (1.5 S ) Py+Pb 1 2/3 S u Py+Pb 1 1 2 (l*5 Sh ) Yield quake

$ cs i-pl CASE III Design Loads + P, 1 2/3 Su Pg i 2/3 S u Pm 1 1.2 sh Deflection of

• Maximum Possible supports limited (Larger) Earth- P1+Pb 1 2/3 Su Py+Pb 1 2/3 Su Py+Pb 1 1*2 (l*5 Sh) to maintain sup-quake & Pipe ported equipment Rupture Loads within their stress limits Where P6 = primary general membrane stress; or stress intensity Py = primary local membrane stress; or stress intensity Pb = primary bending stress; or stress intensity S,= stress intensity value from ASME B & PV Code,Section III -

Sh = allowable stress from USASI B317 Code for Pressure Piping ta Cf Su = uloimate tensile strength of material at temperature

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